JP2024178848A - Measuring device, diagnostic device and filter device - Google Patents

Abstract

[Problem] The amount of moisture contained in oil can be measured with a measuring device attached to a filter. [Solution] A measuring device attached to a filter device having a filter medium for filtering oil comprises a housing attached to the filter device, and a moisture-in-oil meter attached to the housing for measuring the moisture contained in the oil. The moisture-in-oil meter is attached to the housing, and the columnar tip of the housing is disposed inside the filter device, and the moisture-in-oil meter is attached to the tip of the housing so as to come into contact with the oil. [Selected Figure] Figure 1

Description

The present invention relates to a measuring device, a diagnostic device, and a filter device.

Patent Document 1 discloses a filter device in which a metal head is provided to cover the opening of a filter case, a cylindrical filter medium is provided in the internal space formed by the filter case and the head, an IC tag is provided between the filter medium and the plate, and an antenna unit is provided on the head having an antenna portion including an antenna capable of communicating with the IC tag. In this filter device, the antenna unit has a substantially columnar case at least a portion of which is inserted into the head, the antenna portion is provided adjacent to a first end which is one end of the case, the case is provided on the head such that the antenna portion is exposed when the head is viewed from the filter case side, and a metal plate is provided near the opening of the filter case, and the plate has a hole for exposing the IC tag.

In addition, Non-Patent Document 1 discloses that the amount of water contained in oil for vapor deposition can be electrically measured based on the dielectric properties of the oil.

JP 2021-074675 A Tomokazu Arai and Bunjiro Ichijo, "Research on Capacitive Electric Moisture Meter for Oil," Journal of the Institute of Electrical Engineers of Japan, September 1959, Vol. 79, No. 852, pp. 1146-1150

The antenna unit described in Patent Document 1 has a measuring unit that measures the pressure or temperature in the space formed by the filter case and the head, so that the measuring unit and antenna can be provided in the filter device simply by attaching the antenna unit to the head. The measuring unit measures the pressure and temperature, making it possible to detect whether the filter medium in the filter device has become clogged beyond a predetermined amount.

In recent years, there has been a demand to monitor not only the clogging of filter media, but also the deterioration status of the oil filtered by the filter media. As shown in Non-Patent Document 1, it is also known that the deterioration status of oil can be estimated by measuring the amount of moisture contained in the oil. However, it is difficult to measure the amount of moisture contained in oil with the antenna unit described in Patent Document 1.

The present invention was made in consideration of these circumstances, and aims to provide a measuring device that is attached to a filter and is capable of measuring the amount of moisture contained in oil, and a diagnostic device equipped with said measuring device. It also aims to provide a filter device equipped with a small measuring device that can measure the amount of moisture contained in oil.

In order to solve the above problem, the measuring device according to the present invention is, for example, a measuring device provided in a filter device having a filter medium for filtering oil, and includes a housing attached to the filter device, and a moisture-in-oil meter provided in the housing for measuring the moisture contained in the oil, the housing having a columnar tip disposed inside the filter device, and the moisture-in-oil meter provided at the tip of the housing so as to come into contact with the oil.

In order to solve the above problem, the filter device according to the present invention includes, for example, the above-mentioned measuring device, a filter case having a substantially bottomed cylindrical case with an open upper end and a head provided on the case so as to cover the upper end of the case, and a filter element provided in the internal space of the filter case, the filter element having a cylindrical filter medium, and the measuring device is provided on the filter case so that the tip portion is exposed to the space formed by the filter case and the filter element.

According to the measuring device and filter device equipped with said measuring device of the present invention, a housing of the measuring device is attached to a filter device equipped with a filter case and a filter element (having a cylindrical filter material) provided in the internal space of the filter case, and the housing is provided with a moisture-in-oil meter that measures the moisture contained in the oil filtered by the filter material. The columnar tip of the housing is disposed inside the filter device, and the moisture-in-oil meter is provided at the tip of the housing so as to be in contact with the oil. This makes it possible to measure the amount of moisture contained in the oil using the measuring device attached to the filter.

The present invention may also be a diagnostic device that includes the above-mentioned measurement device and a control unit that determines the deterioration of the oil based on the measurement results of the moisture-in-oil meter.

The moisture meter in oil has a capacitor having two metal plate-shaped members, and the housing has a cavity provided at the tip and a hole that connects the cavity to the outside of the housing and allows the oil to flow into the cavity, the capacitor is provided in the cavity, and the plate-shaped members may be provided along a plane that is approximately perpendicular to the central axis of the tip. By providing the moisture meter in oil in a cavity provided near the tip arranged inside the filter device and providing a hole in the housing that connects the cavity to the outside of the housing, the moisture meter in oil can come into contact with the oil and measure the amount of moisture contained in the oil with the moisture meter in oil. In addition, by arranging the plate-shaped members along a plane that is approximately perpendicular to the central axis of the tip, the surface area of the plate-shaped members 72a is increased. Therefore, the accuracy of measuring the dielectric constant by the moisture meter in oil can be improved.

The moisture-in-oil meter may have a plurality of the capacitors, and all of the plate-like members may be arranged in parallel and adjacent to each other. By having the moisture-in-oil meter have a plurality of capacitors, the surface area of the moisture-in-oil meter can be increased, and the measurement accuracy of the dielectric constant can be improved. Also, by arranging all of the plate-like members in parallel and adjacent to each other, many capacitors can be provided in a narrow cavity.

The filter device may further include at least one of a viscosity sensor provided on a plate-shaped substrate for measuring the viscosity of the oil, a differential pressure detection unit for detecting the differential pressure between the pressure upstream and downstream of the filter medium of the filter device, or a temperature sensor for measuring the temperature of the oil. Since the measurement unit has at least one of a viscosity sensor, a differential pressure detection unit, or a temperature sensor, the estimation accuracy of the deterioration state of the oil is higher than that based only on the moisture-in-oil meter.

The plate-like substrate may have a vibrator with a double spiral structure in which a first member and a second member, each of which is formed by winding a columnar member in a spiral shape, are arranged opposite each other, and a driving unit including a piezoelectric element arranged on the first member. This prevents the viscosity sensor from protruding from the plate-like substrate, and allows the viscosity sensor to be arranged in a narrow space.

A viscosity sensor for measuring the viscosity of the oil, comprising a plate-shaped plate-shaped substrate provided with a vibrator having a double spiral structure in which a first member and a second member formed by spirally winding a columnar member are provided opposite each other, and a driving unit including a piezoelectric element provided on the first member, the plate-shaped substrate having a first conductive pattern connected to the piezoelectric element and a second conductive pattern provided adjacent to the vibrator, the moisture-in-oil meter including the second conductive pattern, the second conductive pattern may include a capacitor having a pair of third and fourth conductive patterns provided adjacent to each other. In this way, by providing a viscosity sensor having a vibrator and a piezoelectric element having a double spiral structure and the second conductive pattern of the moisture-in-oil meter on the same plate-shaped substrate, the sensor unit 70 can be made thinner (smaller) and the tip of the housing can be made smaller. This reduces the amount of protrusion of the measurement unit into the filter device, and increases the freedom of arrangement of the measurement unit.

The housing has a hollow portion provided in the tip portion and a hole that connects the hollow portion to the outside of the housing, and the plate-like substrate is provided in the hollow portion, and the plate-like substrate may be provided along a plane that is approximately perpendicular to the central axis of the tip portion. By providing the plate-like substrate along a plane that is approximately perpendicular to the central axis of the tip portion, the hollow portion can be narrowed and the tip portion of the housing can be made smaller. This reduces the amount of protrusion of the measurement unit into the filter device, and increases the freedom of positioning of the measurement unit.

The moisture-in-oil meter has a flexible sheet member made of an organic material, and the sheet member may include a capacitor having a pair of fifth and sixth conductive patterns formed by carbonizing the surface of the sheet member. By using a moisture-in-oil meter made of a flexible sheet member made of an organic material, the moisture-in-oil meter can be attached to the side of a housing that is not flat. This increases the freedom of positioning the moisture-in-oil meter. In addition, because the moisture-in-oil meter is compact, the tip of the measurement unit can be made smaller, increasing the freedom of positioning in the filter device.

According to the present invention, the amount of water contained in oil can be measured using a measuring device attached to the filter.

1 is a cross-sectional view showing an outline of a filter device 1 and a measuring unit 2. FIG. 2 is a cross-sectional view showing an outline of a measuring unit 2. FIG. FIG. 2 is a side view (partially enlarged) showing an outline of the measurement unit 2. FIG. 2 is a cross-sectional view (partially enlarged) showing an outline of a measurement unit 2. FIG. 2 is a block diagram showing the electrical configuration of a control unit 100. 2 is a cross-sectional view showing an outline of a measuring unit 3. FIG. FIG. 2 is a cross-sectional view (partially enlarged) showing an outline of a measurement unit 3. FIG. 2 is a plan view (as viewed from the z direction) showing an outline of a sensor unit 70A. FIG. 4 is a diagram showing an outline of a viscosity sensor 74. FIG. 2 is a block diagram showing the electrical configuration of a control unit 100A. 2 is a cross-sectional view showing an outline of a measuring unit 4. FIG. 1A and 1B are diagrams showing an outline of a moisture-in-oil meter 75, in which FIG. 1A is an exploded perspective view, and FIG. FIG. 2 is a cross-sectional view showing an outline of a measuring unit 4A.

The embodiment of the present invention will be described in detail below with reference to the drawings. The filter device of the present invention is for removing dust and other particles contained in oil, such as oil and fuel. Various filters such as fuel filters and return filters can be used in the filter device of this embodiment. The filter device will be described below using a return filter as an example. The measuring device of the present invention is provided in the filter device and measures the amount of water contained in the oil filtered by the filter device.

First Embodiment
Fig. 1 is a cross-sectional view showing an outline of a filter device 1 and a measuring unit 2. In Fig. 1, some hatching indicating a cross section is omitted.

The filter device 1 mainly comprises a case 10, a filter element 20, a head 30, and an IC tag 40. The measurement unit 2 is attached to the filter device 1 when in use. The IC tag 40 is a small electronic component that can communicate with an antenna 90 (described in detail later) provided in the measurement unit 2, and uses radio waves received from the antenna 90 to read and write data in a built-in memory in a non-contact manner. Note that the IC tag 40 and the antenna 90 are not essential.

The case 10 is made of a highly corrosion-resistant metal (e.g., stainless steel) and is provided so as to protrude from the top surface of the tank 120 into the interior of the tank 120. Note that, although the case 10 is integrated with the tank 120 in FIG. 1, the case 10 may be formed as a separate part from the tank 120.

The case 10 is cylindrical with a bottom and an open top surface. The case 10 is hollow inside, and a head 30 is provided to cover the opening at the top end. The filter element 20 and other components are provided inside the case 10 and head 30 (corresponding to the filter case of the present invention).

The case 10 has a bottom surface 11. An outflow section 12 is provided so as to penetrate the bottom surface 11. The outflow section 12 communicates between the space inside the filter element 20 (space S2) and the space outside the case 10.

An inlet 13 is provided on the side of the case 10. The inlet 13 allows oil to flow into the space (space S1) formed by the filter case (here, the case 10) and the filter element 20.

The positions of the outlet section 12 and the inlet section 13 are not limited to this. In addition, the outlet section 12 and the inlet section 13 may be provided in the filter case, for example, in the head 30.

The filter element 20 is a tubular (here, cylindrical) member and is provided in the internal space formed by the case 10 and the head 30. The filter element 20 mainly has a filter medium 21, an inner tube 22, a plate 24, and a plate 25.

The filter material 21 is a member for filtering oil, and is a tubular (here, cylindrical) member with openings at both ends. The filter material 21 is formed by pleating filter paper made of synthetic resin, paper, etc., and connecting both ends of the pleated filter paper to form a cylinder. An inner tube 22 is provided inside the filter material 21, and has holes formed over almost the entire area through which oil can pass. Note that the inner tube 22 is not essential. Also, an outer tube may be provided outside the filter material 21, and has holes formed over almost the entire area through which oil can pass.

A resin plate 24 is provided at the upper end of the filter medium 21. The plate 24 covers the upper end surfaces of the filter medium 21 and the inner tube 22. The plate 24 and the filter medium 21 are bonded together with an adhesive. Various types of organic adhesives whose main material is resin, rubber, or elastomer can be used as the adhesive.

The filter material contacts the underside of the plate 24, and the head 30 is inserted into the inner peripheral surface. The plate 24 also has a protrusion 24a that protrudes upward (toward the opposite side to the filter material 21), and an IC tag 40 is provided on the protrusion 24a.

A plate 25 is provided at the lower end of the filter medium 21. The plate 25 is a generally hollow disk-shaped member that covers the filter medium 21 and the lower end surface of the inner tube 22. A recess 25a into which the filter medium 21 is inserted is formed on the upper surface of the plate 25. The recess 25a and the filter medium 21 are bonded with an adhesive.

The outflow part 12 is inserted into the hole 25b formed in the approximate center of the plate 25. The hole 25b and the outflow part 12 are sealed by a sealing member (e.g., an O-ring) 91.

The head 30 is attached to the case 10 and the plate 24 so as to cover the opening on the upper end surface of the case 10.

The head 30 is formed from a highly corrosion-resistant metal (e.g., stainless steel). The head 30 mainly has a tubular portion 31, a cover 32, and an attachment portion 33. The tubular portion 31 is tubular (here, cylindrical) and is fixed to the case 10. The cover 32 is a plate-shaped member and is provided on the upper side (+z side) of the tubular portion 31 so as to cover the hollow portion of the tubular portion 31. The cover 32 is detachable from the tubular portion 31. The cover 32 and the tubular portion 31 are sealed by a seal member (e.g., an O-ring) 93.

The cover 32 is provided with an attachment portion 33. The attachment portion 33 is a cylindrical member that protrudes downward from the cover 32. A valve 47 is provided at the tip of the attachment portion 33 (the end on the bottom surface 11 side). The attachment portion 33 is inserted into the hollow portion of the plate 24, and the valve 47 is inserted into the space S2. The attachment portion 33 and the plate 24 are sealed by a seal member (e.g., an O-ring) 92. Normally, the valve 47 is closed, but when the filter medium 21 becomes clogged and the pressure inside the case 10 increases, the valve 47 opens and oil flows from the space S1 to the space S2, preventing damage to the filter device 1. The valve 47 is already known, so a description thereof will be omitted.

The inner diameter of the cylindrical portion 31 is larger than the outer diameter of the plate 24. A hole 31a is formed in the side of the cylindrical portion 31, penetrating the side. The measurement unit 2 is provided in the cylindrical portion 31 by inserting and fixing the measurement unit 2 into the hole 31a, and the tip of the measurement unit 2 is disposed inside the filter device (here, space S1). The cylindrical portion 31 (hole 31a) and the measurement unit 2 are sealed by sealing members (e.g., O-rings) 94 and 95.

The head 30 is provided with a flow path 35 that connects the space S2 to the hole 31a. One end of the flow path 35 opens into the space S2, and the other end opens into the side of the hole 31a.

Next, the measurement unit 2 will be described. FIG. 2 is a cross-sectional view showing an outline of the measurement unit 2. FIG. 3 is a side view showing an outline of the measurement unit 2, and an enlarged view of a portion of the measurement unit 2. FIG. 4 is a cross-sectional view showing an outline of the measurement unit 2, and an enlarged view of a portion of the measurement unit 2. Some of the hatching showing the cross section has been omitted in FIGS. 2 and 4.

The measurement unit 2 mainly has a housing 50, a differential pressure detection section 60, a sensor section 70, and an antenna 90. Hereinafter, the longitudinal direction of the housing 50 is referred to as the z direction, and the two directions perpendicular to the z direction are referred to as the x direction and the y direction. In addition, the x direction and the y direction are perpendicular to each other.

The housing 50 mainly comprises a case 51, covers 52 and 53, an insert member 54, and a fixing member 55. The case 51 has columnar portions 51v and 51w that are attached to the filter device 1 (see FIG. 2). The columnar portion 51v has a male thread 51x formed on the outer circumferential surface, and the male thread 51x is screwed into a female thread (not shown) formed in the hole 31a, thereby attaching the housing 50 to the hole 31a, and the tip of the housing 50 (here, at least a part of the cover 53 including the bottom surface 53c) is disposed inside the filter device 1 (here, space S1, see FIG. 1).

The covers 52 and 53 are cylindrical with bottoms, and are provided on both ends of the case 51. The cover 52 is provided to cover one end (+z side) of the case 51, and the cover 53 is provided to cover the other end (-z side) of the case 51. The case 51 and the cover 52 are sealed by a sealing member (e.g., an O-ring) 96, and the case 51 and the cover 53 are sealed by a sealing member (e.g., an O-ring) 97.

Case 51 has holes 51a, 51b, 51c, 51d, groove 51e, 51f, and 51k. Both ends of case 51 are end faces 51m and 51n, respectively.

Hole 51a, hole 51b, and hole 51d are integrated, and hole 51d opens to end face 51n. Hole 51b is provided closer to end face 51m (+z side) than hole 51d, and hole 51a is provided closer to end face 51m than hole 51b. The diameter of hole 51b is larger than the diameter of hole 51a, and the diameter of hole 51d is larger than the diameter of hole 51b. One end of hole 51c opens to the bottom face of hole 51b, and the other end opens to end face 51n. Hole 51k opens to end face 51m.

A groove 51e is provided in the hole 51d. An insert member 54 is provided in the hole 51d and the hole 51b, and a fixing member 55 is provided in the groove 51e. The insert member 54 has a small diameter portion 54a and a large diameter portion 54b having a diameter larger than that of the small diameter portion 54a. The large diameter portion 54b is inserted into the hole 51d, and the small diameter portion 54a is inserted into the hole 51b. By attaching the fixing member 55 to the groove 51e with the insert member 54 inserted into the hole 51d and the hole 51b, the end of the hole 51a on the end face 51n side is covered. As a result, a hollow portion S3 with both ends covered is provided inside the columnar portions 51v and 51w.

The hollow section S3 is provided with a differential pressure detection section 60 that detects the differential pressure between the pressure on the upstream side and the pressure on the downstream side of the filter medium 21. The differential pressure detection section 60 mainly has a detection unit 61, a spool 62, a magnet 63, and an elastic member 64.

The spool 62 has a cylindrical shape and is movable in the z direction inside the hollow portion S3. The outer peripheral surface 62b slides along the hole 51b, causing the spool 62 to move in the z direction.

The spool 62 divides the hollow portion S3 into a space S4 and a space S5. One end of the hole 51f opens into the space S5. The case 51 and the insert member 54 are sealed by a sealing member (e.g., an O-ring) 98.

The hole 51f penetrates the side surface of the columnar portion 51v in the radial direction (here, the x direction), and the other end of the hole 51f opens to the outer peripheral surface of the columnar portion 51v. As a result, the hole 51f communicates with the space S5 and the space S1 (the upstream side of the filter medium 21, see FIG. 1). In addition, a hole (not shown) that penetrates the side surface of the columnar portion 51v in the radial direction communicates with the space S4 and the space S2 (the downstream side of the filter medium 21, see FIG. 1) together with the flow path 35.

The elastic member 64 is, for example, a coil spring, with one end attached to the spool 62 and the other end attached to the bottom surface of the hole 51b. The elastic member 64 exerts a force in the -z direction on the spool 62. The magnet 63 is provided on the surface of the spool 62 facing the bottom surface of the hole 51a, i.e., on the surface of the spool 62 on the end surface 51m side.

The detection unit 61 is provided inside the hole 51k. The position of the detection unit 61 in the z direction is adjustable.

The detection unit 61 is provided with a magnetic field detection element 61a. The magnetic field detection element 61a detects changes in the magnetic field generated by the magnet 63. The magnetic field detection element 61a may be a reed switch, a Hall element, or the like. The detection result of the magnetic field detection element 61a is output to the outside of the measurement unit 2 via a signal line (not shown). The reed switch and the Hall element are already known, so a description thereof will be omitted.

The cover 53 is provided on the outside of the columnar portion 51v. At least a portion of the cover 53 corresponds to the tip of the measurement unit 2. The cover 53 is generally columnar.

Since the cover 53 has a configuration in which one end of the cylindrical portion 53d is covered by the bottom surface 53c, providing the cover 53 to the case 51 forms a space S6 (corresponding to the hollow portion of the present invention) at the tip of the housing 50. The sensor unit 70 and the antenna 90 are provided in this space S6. The sensor unit 70 and the differential pressure detection unit 60 are provided on the case 51 side relative to the antenna 90.

The cover 53 has holes 53a and 53b that penetrate the side surface of the cover 53 in the radial direction. Since the cover 53 is disposed inside the filter device 1 (space S1, see FIG. 1), the holes 53a and 53b communicate between the space S1 and the space S6.

The antenna 90 is provided along the bottom surface 53c of the cover 53. That is, the antenna 90 is provided in the space S6, i.e., at the tip of the measurement unit 2. The antenna 90 includes a wiring pattern (antenna coil pattern) formed on one surface of the antenna 90 (e.g., the surface facing the bottom surface 53c). The antenna 90 is covered with resin (not shown) while provided on the bottom surface 53c. Therefore, the antenna 90 does not come into contact with oil.

A sensor unit 70 is also provided in the space S6. The sensor unit 70 has a temperature sensor 71 that measures the temperature of the oil and a moisture meter 72 in the oil.

The temperature sensor 71 is, for example, a plate-shaped substrate on which a thermocouple is mounted. The temperature sensor 71 is provided along a plane that is approximately perpendicular to the central axis of the space S6 (here, the central axis ax of the cover 53).

The moisture-in-oil meter 72 has multiple (here, two) capacitors 72b each having two metal plate-shaped members 72a. In this embodiment, the moisture-in-oil meter 72 has four plate-shaped members 72a. The moisture-in-oil meter 72 can measure the dielectric constant of the oil by applying a DC voltage between the plate-shaped members 72a (electrodes) and measuring the amount of accumulated charge (capacitance).

The plate-like members 72a are arranged along a plane that is approximately perpendicular to the central axis ax. Furthermore, all the plate-like members 72a are arranged parallel to each other and adjacent to each other. By arranging the plate-like members 72a in this manner, the surface area of the plate-like members 72a is increased, and the measurement accuracy of the dielectric constant is improved.

The temperature sensor 71 and the moisture-in-oil meter 72 are provided adjacent to each other. In this embodiment, the temperature sensor 71 is provided closer to the columnar portion 51v (in the +z direction) than the moisture-in-oil meter 72, but the arrangement of the temperature sensor 71 and the moisture-in-oil meter 72 is not limited to this. For example, the moisture-in-oil meter 72 may be provided closer to the columnar portion 51v than the temperature sensor 71.

The temperature sensor 71 and the moisture-in-oil meter 72 may be located apart. However, in order to accurately grasp the condition of the oil, it is desirable to place the temperature sensor 71 and the moisture-in-oil meter 72 in close proximity (for example, adjacent to each other).

A lead wire 81 is connected to the temperature sensor 71, and a lead wire 82 is connected to the moisture in oil meter 72 (plate-shaped member 72a). An antenna wire 83 is connected to the antenna coil pattern of the antenna 90. A hole 51c is provided in the case 51 along the central axis ax, and the lead wires 81, 82 and antenna wire 83 pass through the inside of the hole 51c and are attached to the substrate 85 at their ends.

An IC chip (not shown) and the like are mounted on the substrate 85. When radio waves are received from the IC tag 40, a received signal is generated on the substrate 85 via an antenna line, and the signal is output to the outside of the measurement unit 2 via a signal line (not shown). Similarly, the measurement results of the temperature sensor 71 and the moisture in oil meter 72 are also transmitted to the substrate 85.

The substrate 85 has a control unit 100 that performs processing. FIG. 5 is a block diagram showing the electrical configuration of the control unit 100. Functionally, the control unit 100 mainly has a measurement data acquisition unit 101, a deterioration estimation unit 102, and a memory unit 103.

The functional components of the control unit 100 may be further classified into more components depending on the processing content, or one component may execute the processing of multiple components.

The measurement data acquisition unit 101 acquires measurement results from the temperature sensor 71 and the in-oil moisture meter 72 of the sensor unit 70. The measurement results from the temperature sensor 71 and the in-oil moisture meter 72 are output from the measurement data acquisition unit 101 to the deterioration estimation unit 102. The deterioration estimation unit 102 acquires the oil temperature based on the measurement results from the temperature sensor 71, and acquires the dielectric constant based on the measurement results from the in-oil moisture meter 72. The method of acquiring the temperature and dielectric constant from the measurement results from the temperature sensor 71 and the in-oil moisture meter 72 is well known, so a description thereof will be omitted.

The memory unit 103 stores information related to the dielectric constant, including the temperature characteristics of the dielectric constant of the oil (the relationship between temperature and dielectric constant), the relationship between the dielectric constant and the moisture content, and the relationship between the moisture content, dielectric constant, and oil deterioration. The deterioration estimation unit 102 acquires information related to the dielectric constant from the memory unit 103 and estimates the degree of deterioration of the oil based on this information and the measurement results of the temperature sensor 71 and the moisture meter in oil 72. As various known techniques can be used as a method for determining deterioration of the oil based on the dielectric constant, etc., a description thereof will be omitted. The deterioration estimation unit 102 outputs the estimation result to the outside of the measurement unit 2 via a signal line (not shown).

For example, the control unit 100 can be configured with an IC mounted on the substrate 85. The control unit 100 may also be configured with a computer system including an arithmetic device such as a CPU (Central Processing Unit) for executing information processing, and a storage device such as a RAM (Random Access Memory) or a ROM (Read Only Memory). For example, the measurement results of the temperature sensor 71 and the moisture content in oil meter 72 may be output to an external computer system via a signal line (not shown), and the deterioration state of the oil may be estimated by the computer system.

Next, the functions of the filter device 1 and measurement unit 2 configured in this manner will be explained using Figures 1 to 5.

When the engine of the work machine is running, oil flows into space S1 inside the case 10, as shown by the dashed double-dashed arrow in Figure 1. The oil that flows into space S1 flows from the outside to the inside of the filter material 21, and dust and other particles in the oil are removed by the filter material 21. The filtered oil flows out into space S2. The filtered oil then flows out of the outflow section 12 into the inside of the tank.

When the case 10 is filled with oil, the differential pressure detection section 60 of the measurement unit 2 shown in Figure 2 detects the differential pressure between the pressure on the upstream side (space S1) and the pressure on the downstream side (space S2) of the filter medium 21.

When the filter material 21 is not clogged and the pressure in the spaces S1 and S5 is low, the spool 62 is pushed toward the insertion member 54 by the biasing force of the elastic member 64, and the magnet 63 is located at the farthest position from the bottom surface of the hole 51a.

When the pressure in the space S1 increases due to clogging of the filter medium 21, the spool 62 moves toward the bottom side of the hole 50a against the biasing force of the elastic member 64. The detection unit 61 detects the change in the magnetic field caused by the movement of the magnet 63 and transmits the detection result to an external device.

Since clogging of the filter medium 21 is roughly proportional to the operating time of the filter element 20, the operating time of the filter element 20 is measured by the IC tag 40, the antenna 90 reads the IC tag 40, and the reading result is transmitted from the measurement unit 2 to the external device. Furthermore, if a counterfeit product not provided with the IC tag 40 is used as the replaced filter element, the IC tag 40 cannot be read, and the external device can display an error or prevent the filter device from operating. Furthermore, for example, by reading the IC tag 40 provided on the replaced filter element 20, the external device can determine that a filter element other than the specified filter element has been installed.

In addition, oil flows into the space S6 through the holes 53a and 53b, so that the oil comes into contact with the temperature sensor 71 and the moisture-in-oil meter 72. This allows the sensor section 70 of the measurement unit 2 to measure the temperature and dielectric constant of the oil. Since the dielectric constant is temperature-dependent, the deterioration estimation section 102 corrects the measurement result of the dielectric constant in the moisture-in-oil meter 72 based on the measurement result in the temperature sensor 71, and estimates the degree of deterioration of the oil based on the corrected result and information on the dielectric constant. In addition, the differential pressure detected by the differential pressure detection section 60 changes when the filter material 21 becomes clogged with dust or the like caused by deterioration of the oil, or when the viscosity of the oil increases due to deterioration of the oil. Therefore, the deterioration estimation section 102 uses the measurement result in the differential pressure detection section 60 to finally estimate the degree of deterioration of the oil.

According to this embodiment, by providing the filter device 1 with a measurement unit 2 having a moisture meter 72 in oil, the amount of moisture contained in the oil filtered by the filter medium 21 can be measured. As a result, the control unit 100 can estimate the deterioration state of the oil. In addition, by using the measurement results of the temperature sensor 71, the accuracy of estimating the deterioration state of the oil can be improved.

In addition, according to this embodiment, the cover 53 is placed inside the filter device 1 (space S1), a space S6 is formed inside the cover 53, and a hole 53a is provided in the cover 53 that connects the outside of the housing 50 (space S1) with the space S6, so that the moisture-in-oil meter 72 can be provided in the measurement unit 2 (here, space S6) so as to come into contact with the oil. This makes it possible to measure the amount of moisture contained in the oil simply by including the moisture-in-oil meter 72 in the measurement unit 2 and providing the measurement unit 2 in the filter device 1. Similarly, the temperature of the oil can be measured simply by including a temperature sensor 71 in the measurement unit 2 and providing the measurement unit 2 in the filter device 1.

In addition, according to this embodiment, the plate-shaped member 72a is arranged along a plane that is approximately perpendicular to the central axis ax, so that the surface area of the plate-shaped member 72a is increased, and the measurement accuracy of the dielectric constant can be improved. In addition, since the moisture-in-oil meter 72 has multiple capacitors 72b, the measurement accuracy of the dielectric constant can be improved.

In addition, according to this embodiment, by arranging all the plate-like members 72a in parallel and adjacent to each other, the cover 53, i.e., the tip of the measurement unit 2, can be made smaller (thinner). Also, many capacitors 72b can be provided in the narrow cavity (space S6).

In this embodiment, the differential pressure detection unit 60 is provided inside the case 51, but the differential pressure detection unit 60 is not essential. The temperature sensor 71 is also not essential. The measurement unit 2 only needs to be provided with at least the moisture in oil meter 72. The sensor unit 70 may include sensors other than the temperature sensor 71 and the moisture in oil meter 72. For example, the sensor unit 70 may further include a viscosity sensor that measures the viscosity of oil. The viscosity sensor is provided on a plate-shaped substrate, and the plate-shaped substrate and the moisture in oil meter 72 are provided adjacent to each other, so that the cover 53 can be made smaller (thinner). The viscosity sensor can be an actuator such as MEMS (Micro Electro Mechanical Systems) or QCM (Quartz Crystal Microbalance). In addition, by using a vibrator with a double spiral structure and a drive unit including a piezoelectric element for the viscosity sensor (see the viscosity sensor 74 described in detail later), the viscosity sensor can be made thinner and the viscosity sensor can be prevented from protruding from the plate-shaped substrate. As a result, the viscosity sensor can be provided in a narrow space.

In addition, in this embodiment, the moisture-in-oil meter 72 has two capacitors 72b, but the number of capacitors 72b that the moisture-in-oil meter 72 has is not limited to this. The moisture-in-oil meter 72 may have only one capacitor 72b. However, since the surface area increases with each increase in the number of capacitors 72b, and the measurement accuracy of the dielectric constant increases, it is desirable for the moisture-in-oil meter 72 to have multiple capacitors 72b.

Second Embodiment
The second embodiment of the present invention is an embodiment in which the moisture-in-oil meter is different from the measurement unit 2. The measurement unit 3 according to the second embodiment will be described below. Note that the same parts as those in the first embodiment are given the same reference numerals and the description will be omitted. Also, the measurement unit 3 according to the second embodiment is attached to the filter device 1 in the same manner as in the first embodiment, and therefore the description will be omitted.

Figures 6 and 7 are cross-sectional views showing an outline of the measurement unit 3. Figure 7 shows an enlarged view of a portion of Figure 6. The measurement unit 3 mainly includes a housing 50A, a differential pressure detection unit 60, a sensor unit 70A, and an antenna 90.

The housing 50A mainly comprises a case 51, covers 52 and 53A, an insert member 54, and a fixing member 55. The cover 53A is provided on the outside of the columnar portion 51v so as to cover the end of the case 51 on the -z side. Therefore, at least a portion of the cover 53A corresponds to the tip of the housing 50A. The cover 53A is generally columnar. By providing the cover 53A to the case 51, a space S7 (corresponding to the hollow portion of the present invention) is formed at the tip of the housing 50A. The space S7 has a lower height (distance in the z direction) and a smaller volume than the space S6. In addition, a hole 53a (not shown) is formed in the cover 53A.

A sensor unit 70A and an antenna 90 are provided in the space S7. The antenna 90 is provided along the bottom surface 53c, and the sensor unit 70A is provided closer to the case 51 than the antenna 90. The sensor unit 70A is provided along a plane that is approximately perpendicular to the central axis of the space S7 (here, the central axis ax of the cover 53A). One end of a lead wire 84 is provided to the sensor unit 70A. The lead wire 84 and the antenna wire 83 pass through the inside of the hole 51c, and the other end is provided to the substrate 85.

Figure 8 is a plan view (viewed from the +z direction) showing an outline of the sensor unit 70A. The sensor unit 70A is a plate-shaped substrate 70a on which a moisture-in-oil meter 73 and a viscosity sensor 74 are provided. The lead wire 84 has two lead wires, one of which is connected to the moisture-in-oil meter 73 and the other is connected to the viscosity sensor 74.

The moisture-in-oil meter 73 has two electrode patterns 73a and 73b (corresponding to the second conductive pattern of the present invention) provided on a plate-shaped substrate 70a. The electrode patterns 73a and 73b each have a pattern 73c (corresponding to the third conductive pattern of the present invention) and a pattern 73d (corresponding to the fourth conductive pattern of the present invention). The patterns 73c and 73d are provided adjacent to each other. One end of a lead wire 84 is provided on each of the patterns 73c and 73d.

Patterns 73c and 73d are included in a capacitor. When a DC voltage is applied to patterns 73c and 73d via lead wire 84 and electrode patterns 73a and 73b, an electric charge accumulates between patterns 73c and 73d. By measuring the amount of this electric charge (capacitance), the dielectric constant of the oil can be measured.

The viscosity sensor 74 measures the viscosity of the oil. The viscosity sensor 74 mainly has an oscillator 741 and a pattern 742 (corresponding to the first conductive pattern of the present invention). The pattern 742 is provided adjacent to the oscillator 741, and one end of a lead wire 84 is provided on the pattern 742.

In this embodiment, the moisture-in-oil meter 73 and the pattern 742 are provided on the +z surface of the plate-shaped substrate 70a, but the moisture-in-oil meter 73 and the pattern 742 may be provided on the -z surface of the plate-shaped substrate 70a.

Figure 9 is a diagram showing an outline of the viscosity sensor 74. The vibrator 741 has a vibrating body 74a (corresponding to the first member of the present invention) and a force sensor 74b (corresponding to the second member of the present invention) which are made by winding a rod-shaped member in a spiral shape. The vibrator 741 has a double spiral structure in which the vibrating body 74a and the force sensor 74b are arranged opposite each other. A gap of several μm to several hundred μm is provided between the vibrating body 74a and the force sensor 74b. The ends located at the outermost periphery (outer ends 74c, 74d) of the vibrating body 74a and the force sensor 74b are fixed to a substrate or the like, and the ends in the center (center ends 11e, 12f) are freely movable.

The oscillator 741 has a driving unit 743 and a displacement measuring unit 744. The oscillator 741 can be moved by the driving unit 743 in the z direction (the direction perpendicular to the paper surface of FIG. 9), i.e., along the central axis of the oscillator 741.

The driving unit 743 mainly has a plurality of piezoelectric elements 74g and a connecting portion 74h that connects the piezoelectric elements 74g. The connecting portion 74h is connected to the pattern 73c. The piezoelectric elements 74g are connected to a power source via the connecting portion 74h.

The connecting portion 74h extends along the longitudinal direction of the vibrating body 74a. Each of the piezoelectric elements 74g is inclined at approximately 45 degrees with respect to the longitudinal direction of the vibrating body 74a. The piezoelectric elements 74g are arranged side by side along the longitudinal direction of the vibrating body 74a. The piezoelectric elements 74g generate a torsional deformation in the vibrating body 74a, and the central end 11e of the vibrating body 74a is greatly deformed in the z direction.

The displacement measuring unit 744 is a piezoelectric thin film provided on the surface of the vibrating body 74a and the force sensing body 74b. The displacement measuring unit 744 mainly has a plurality of displacement sensors 74i and a connecting portion 74j that connects the displacement sensors 74i. The connecting portion 74j is connected to the pattern 73d.

The connecting portion 74j extends along the longitudinal direction of the vibrating body 74a or the force sensor 74b. The displacement sensor 74i is inclined at approximately 45 degrees with respect to the longitudinal direction of the vibrating body 74a or the force sensor 74b. The multiple displacement sensors 74i are arranged side by side along the longitudinal direction of the vibrating body 74a or the force sensor 74b. Since the deformation due to the twisting of the piezoelectric element 74g is in the longitudinal direction of the vibrating body 74a, by arranging the displacement sensor 74i at an angle of approximately 45 degrees with respect to the direction of deformation of the vibrating body 74a, the amount of deformation at the position where the displacement sensor 74i of the vibrating body 74a is provided can be efficiently measured by each displacement sensor 74i.

Returning to the explanation of Figure 8, the transducer 741 and patterns 73c and 73d are provided adjacent to each other. This allows the viscosity and water content to be measured using oil in a similar environment.

The substrate 85 has a control unit 100A that performs processing. FIG. 10 is a block diagram showing the electrical configuration of the control unit 100A. Functionally, the control unit 100A mainly has a measurement data acquisition unit 101A, a deterioration estimation unit 102A, and a memory unit 103A. Note that the functional components of the control unit 100A may be further classified into more components depending on the processing content, or one component may perform the processing of multiple components.

The measurement data acquisition unit 101A acquires measurement results from the moisture-in-oil meter 73 and viscosity sensor 74 of the sensor unit 70A. The measurement results from the moisture-in-oil meter 73 and viscosity sensor 74 are output from the measurement data acquisition unit 101A to the deterioration estimation unit 102A. The deterioration estimation unit 102A acquires the dielectric constant from the measurement results of the moisture-in-oil meter 73, and acquires the oil viscosity from the measurement results of the viscosity sensor 74. The method of acquiring the viscosity from the measurement results of the viscosity sensor 74 is well known, so a description thereof will be omitted.

The memory unit 103A stores information on the relationship between the dielectric constant of the oil and the moisture content, information on the dielectric constant including the relationship between the moisture content and dielectric constant and the deterioration of the oil, and information on the viscosity including the relationship between the deterioration of the viscous oil. The deterioration estimation unit 102A obtains information on the dielectric constant and viscosity from the memory unit 103A and detects the degree of deterioration of the oil based on this information and the measurement results of the sensor unit 70A. Various known techniques can be used as a method for determining deterioration of the oil based on the dielectric constant, viscosity, etc., so a description thereof will be omitted. The deterioration estimation unit 102A outputs the estimation result to the outside of the measurement unit 2 via a signal line (not shown).

For example, the control unit 100A can be configured with an IC mounted on the substrate 85. The control unit 100A may also be configured with a computer system including an arithmetic device such as a CPU (Central Processing Unit) for executing information processing, and a storage device such as a RAM (Random Access Memory) or a ROM (Read Only Memory). For example, the measurement results of the moisture-in-oil meter 73 and the viscosity sensor 74 may be output to an external computer system via a signal line (not shown), and the deterioration state of the oil may be estimated by the computer system.

Next, the functions of the filter device 1 and the measurement unit 3 thus configured will be described. When the engine of the work machine is running and oil is filling the case 10, the differential pressure detection section 60 of the measurement unit 3 detects the differential pressure between the pressure on the upstream side (space S1) and the downstream side (space S2) of the filter medium 21. When the pressure in space S1 increases due to clogging of the filter medium 21, the spool 62 moves to the bottom side of the hole 50a against the biasing force of the elastic member 64. The detection unit 61 detects the change in the magnetic field caused by the movement of the magnet 63 and transmits the detection result to an external device. In addition, the IC tag 40 measures the operating time of the filter element 20, the antenna 90 reads the IC tag 40, and the measurement unit 2 can transmit the reading result to an external device.

The sensor unit 70A measures the dielectric constant and viscosity of the oil. As the oil flows into the space S7 through the hole 53a, the oil comes into contact with the sensor unit 70A. This allows the control unit 100A to measure the dielectric constant and viscosity of the oil based on the measurement results of the sensor unit 70A, and the deterioration status of the oil can be estimated. In addition, because the sensor unit 70A has an actuator (vibrator 741), it becomes even easier for the oil to flow into and out of the space S7. As a result, the oil present in the space S7 is successively replaced, and the dielectric constant and viscosity of the oil at the current time can be measured.

The deterioration estimation unit 102A estimates the degree of deterioration of the oil based on the measurement results from the moisture-in-oil meter 73. In addition, because the viscosity of the oil increases as the oil oxidizes and deteriorates, the deterioration estimation unit 102A estimates the degree of deterioration of the oil based on the measurement results from the viscosity sensor 74. The deterioration estimation unit 102A then corrects the measurement results from the moisture-in-oil meter 73 using the measurement results from the viscosity sensor 74 to finally estimate the degree of deterioration of the oil.

According to this embodiment, by providing the filter device 1 with a measurement unit 3 having a moisture-in-oil meter 73, the amount of moisture contained in the oil filtered by the filter medium 21 can be measured. As a result, the control unit 100A can estimate the deterioration state of the oil. Furthermore, since the measurement unit 3 has a viscosity sensor 74, the estimation accuracy is higher than that of an estimation of the deterioration state of the oil based only on the measurement results of the moisture-in-oil meter 73.

In addition, according to this embodiment, the moisture-in-oil meter 73 and the viscosity sensor 74 are provided on the plate-shaped substrate 70a, and the sensor section 70A is made thin (small), so the space S7, i.e., the cover 53A, can be made small. This reduces the amount of protrusion of the measurement unit 3 into the filter device 1, and increases the freedom of positioning of the measurement unit 3. For example, it becomes possible to position the tip (at least a part of the cover 53A) in a narrow space, and the measurement unit 3 can be positioned in a variety of locations.

In addition, according to this embodiment, the viscosity sensor 74 is used, which has a double spiral structure vibrator and a driving unit including a piezoelectric element, so that the viscosity sensor 74 does not protrude from the plate-shaped substrate 70a. As a result, the viscosity sensor 74 can be provided in a narrow space S7.

In this embodiment, the sensor unit 70A has the moisture meter 73 in oil and the viscosity sensor 74, but the configuration of the sensor unit 70A is not limited to this. For example, the sensor unit 70A may have a temperature sensor that measures the temperature of the oil. Since the viscosity changes with temperature (for example, the viscosity decreases when the defoaming agent deteriorates), if the sensor unit 70A has a temperature sensor, the deterioration of the oil can be estimated more accurately. In addition, the viscosity sensor 74 may be composed of an actuator other than the vibrator 741 (for example, a MEMS). In addition, in this embodiment, as in the measurement unit 2, the differential pressure detection unit 60 is not essential.

Third Embodiment
The third embodiment of the present invention is an embodiment in which the moisture-in-oil meter is different from the filter device 1. A measurement unit 4 according to the third embodiment will be described below. Note that the same parts as those in the first embodiment are given the same reference numerals and their description will be omitted. Also, the measurement unit 4 according to the third embodiment is attached to the filter device 1 in the same manner as in the first embodiment, and therefore its description will be omitted.

Figure 11 is a cross-sectional view showing an outline of the measurement unit 4. The measurement unit 4 mainly has a housing 50B, a differential pressure detection unit 60, a sensor unit 70B, and an antenna 90.

The housing 50B mainly comprises a case 51, covers 52 and 53B, an insert member 54, and a fixing member 55. The cover 53B is provided on the outside of the columnar portion 51v so as to cover the end of the case 51 on the -z side. Therefore, at least a part of the cover 53B corresponds to the tip of the housing 50B. The cover 53B is generally columnar. By providing the cover 53B on the case 51, a space S8 (corresponding to the hollow portion of the present invention) is formed inside the tip (here, the cover 53B). The space S8 has a lower height (distance in the z direction) and a smaller volume than the space S6. In addition, a hole 53a (not shown) is formed in the cover 53B.

A sensor unit 70B and an antenna 90 are provided in the space S8. The antenna 90 is provided along the bottom surface 53c, and the sensor unit 70B is provided closer to the case 51 than the antenna 90. The sensor unit 70B mainly has a temperature sensor 71 and a moisture-in-oil meter 75. One end of a lead wire 82 is provided to the moisture-in-oil meter 75.

The moisture-in-oil meter 75 is flexible and is provided along the inner peripheral surface of the cover 53B. Figure 12 shows an outline of the moisture-in-oil meter 75, where (a) is an exploded perspective view and (b) is a view showing the exterior.

The moisture-in-oil meter 75 is a flexible sheet member made of an organic material. In this embodiment, the moisture-in-oil meter 75 mainly has an organic substrate 75a and a film 75b. However, the film 75b is not essential.

The organic substrate 75a and the film 75b are each formed of an organic material. Various materials can be used as the organic material, but in this embodiment, polyimide is used for the organic substrate 75a and acrylic is used for the film 75b. In addition, the organic substrate 75a and the film 75b are formed in a sheet shape to provide flexibility. In this embodiment, the organic substrate 75a is 50 μm thick and the film 75b is 100 μm thick, but the thickness is not limited to these.

A pair of conductive patterns 75c (corresponding to the fifth conductive pattern of the present invention) and conductive pattern 75d (corresponding to the sixth conductive pattern of the present invention) are formed on the organic substrate 75a. The conductive patterns 75c and 75d are formed by carbonizing the surface of the organic substrate 75a. One end of a lead wire 82 is provided on the conductive patterns 75c and 75d.

The conductive patterns 75c and 75d are adjacent to each other and are included in a capacitor. When a DC voltage is applied to the conductive patterns 75c and 75d via the lead wire 82, an electric charge is accumulated between the conductive patterns 75c and 75d. By measuring the amount of this electric charge (capacitance), the dielectric constant of the oil can be measured.

The substrate 85 has a control unit 100 that performs processing. In the control unit 100, the measurement data acquisition unit 101 acquires the measurement results from the temperature sensor 71 and the moisture-in-oil meter 75, and the deterioration estimation unit 102 acquires the oil temperature from the measurement results of the temperature sensor 71 and the dielectric constant from the measurement results of the moisture-in-oil meter 75, and estimates the deterioration of the oil based on this information and the information stored in the memory unit 103.

Next, the functions of the filter device 1 and the measurement unit 4 thus configured will be described. When the engine of the work machine is running and oil is filled in the case 10, the differential pressure detection section 60 of the measurement unit 4 detects the differential pressure between the pressure on the upstream side (space S1) and the downstream side (space S2) of the filter medium 21. When the pressure in space S1 increases due to clogging of the filter medium 21, the spool 62 moves to the bottom side of the hole 50a against the biasing force of the elastic member 64. The detection unit 61 detects the change in the magnetic field caused by the movement of the magnet 63 and transmits the detection result to an external device. In addition, the IC tag 40 measures the operating time of the filter element 20, the antenna 90 reads the IC tag 40, and the measurement unit 2 can transmit the reading result to an external device.

The sensor unit 70B measures the temperature and dielectric constant of the oil. Because oil flows into the space S8 through the hole 53a, the oil comes into contact with the sensor unit 70B. As a result, the control unit 100 measures the temperature and dielectric constant of the oil based on the measurement results of the sensor unit 70B, and the deterioration status of the oil can be estimated.

According to this embodiment, by providing the filter device 1 with a measurement unit 4 having a moisture meter 75 in oil, the amount of moisture contained in the oil filtered by the filter medium 21 can be measured. As a result, the control unit 100 can estimate the deterioration state of the oil.

In addition, according to this embodiment, since the moisture-in-oil meter 75 is flexible, the moisture-in-oil meter 75 can be curved along the wall surface of the cover 53B. By providing the moisture-in-oil meter 75 on the wall surface of the cover 53B, the space S8, i.e., the cover 53B, can be made smaller. This reduces the amount that the measurement unit 4 protrudes into the filter device 1, making it possible to place the measurement unit 4 in various locations on the filter device 1.

In this embodiment, the moisture-in-oil meter 75 is provided on the wall surface of the cover 53B, but the arrangement of the moisture-in-oil meter 75 is not limited to this. FIG. 13 is a cross-sectional view showing an outline of a measurement unit 4A according to a modified example. The only differences between the measurement unit 4 and the measurement unit 4A are the position of the moisture-in-oil meter 75 and the size of the cover 53C of the housing 50C.

The antenna 90 is covered with resin 91 while attached to the bottom surface 53c of the cover 53C to protect the antenna coil pattern, etc. The moisture-in-oil meter 75 is attached to the surface 91a of the resin 91. Because the moisture-in-oil meter 75 is flexible, the moisture-in-oil meter 75 can be attached to the surface 91a even if the surface 91a is not flat.

In addition, because the moisture-in-oil meter 75 is thin, the space in which the sensor unit 70B is provided, i.e., the height of the cover 53C, can be made thinner (smaller) than the cover 53B. As a result, the housing 50C can be made even smaller. In addition, the amount by which the measurement unit 4A protrudes into the filter device 1 is reduced, making it easier to position the measurement unit 4A.

Furthermore, in the measurement units 4 and 4A according to this embodiment and the modified example, like the measurement unit 2, the differential pressure detection unit 60 and the temperature sensor 71 are not essential. Furthermore, the sensor unit 70B may include sensors other than the temperature sensor 71 and the moisture in oil meter 75.

Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes within the scope of the gist of the present invention are also included. For example, the above examples have been described in detail to clearly explain the present invention, and are not necessarily limited to those having all of the configurations described. In addition, it is possible to replace part of the configuration of an embodiment with the configuration of another embodiment, and it is also possible to add, delete, or replace other configurations to the configuration of an embodiment.

The term "approximately" does not only refer to cases where something is strictly the same, but also includes errors and deformations that do not cause loss of identity. For example, "cylindrical" is not limited to cases where something is strictly cylindrical, but is a concept that includes cases where something can be regarded as the same as a cylinder. For example, when expressing something as simply perpendicular, parallel, coincident, etc., it includes not only cases where something is strictly perpendicular, parallel, coincident, etc., but also cases where something is approximately parallel, approximately perpendicular, approximately coincident, etc.

In addition, "nearby" means including a certain range (which can be determined arbitrarily) near a reference position. For example, "near an end" is a concept that indicates a certain range of area near the end, which may or may not include the end.

1: Filter device 2, 3, 4, 4A: Measuring unit 10: Case 11: Bottom surface 11e: Center end 12: Outlet portion 12f: Center end 13: Inlet portion 20: Filter element 21: Filter medium 22: Inner cylinder 24, 25: Plate 24a: Convex portion 25a: Concave portion 25b: Hole 30: Head 31: Cylindrical portion 31a: Hole 32: Cover 33: Mounting portion 35: Flow path 40: IC tag 47: Valve 50, 50A, 50B, 50C: Housing 51: Case 52, 53, 53A, 53B, 53C: Cover 50a, 51a, 51b, 51d, 51k: Hole 51c, 51f, 53a, 53b: Hole 51e : Groove 51m, 51n: End surface 51v, 51w: Columnar portion 51x: Male thread 53d: Cylindrical portion 53c: Bottom surface 54: Insertion member 54a: Small diameter portion 54b: Large diameter portion 55: Fixing member 60: Differential pressure detection portion 61: Detection unit 61a: Magnetic field detection element 62: Spool 62b: Outer circumferential surface 63: Magnet 64: Elastic member 70, 70A, 70B: Sensor portion 70a: Plate-shaped substrate 71: Temperature sensor 72: Moisture-in-oil meter 72a: Plate-shaped member 72b: Capacitor 73: Moisture-in-oil meter 73a, 73b: Electrode pattern 73c: Pattern 73d: Pattern 74: Viscosity sensor 74a: Vibration body 74b: Force-sensing body 74c, 74d: Outer end 74g: Piezoelectric element 74h : Connection portion 74i : Displacement sensor 74j : Connection portion 75 : Moisture meter in oil 75a : Organic substrate 75b : Film 75c, 75d : Conductive patterns 81, 82, 84 : Lead wire 83 : Antenna wire 85 : Substrate 90 : Antenna 91 : Resin 91a : Surface 100, 100A : Control portion 101, 101A : Measurement data acquisition portion 102, 102A : Deterioration estimation portion 103 : Memory portion 103A : Memory portion 120 : Tank 741 : Transducer 742 : Pattern 743 : Driving portion 744 : Displacement measurement portion

Claims (9)

A measuring device provided in a filter device having a filter medium for filtering oil,
A housing attached to the filter device;
a moisture meter in oil that is provided in the housing and measures moisture contained in the oil;
The housing has a tip portion disposed inside the filter device,
The moisture-in-oil meter is provided at the tip of the housing so as to come into contact with the oil. The moisture-in-oil meter includes a capacitor having two metal plate members,
The housing has a cavity provided at the tip portion, and a hole that communicates the cavity with the outside of the housing and allows the oil to flow into the cavity,
The capacitor is provided in the cavity,
The measuring device according to claim 1 , wherein the plate-like member is provided along a plane substantially perpendicular to a central axis of the tip portion. The moisture-in-oil meter includes a plurality of the capacitors,
3. The measuring device according to claim 2, wherein all of the plate-like members are provided in parallel and adjacent to each other. The measuring device according to any one of claims 1 to 3, further comprising at least one of a viscosity sensor for measuring the viscosity of the oil, a differential pressure detection unit for detecting the differential pressure between the upstream pressure and the downstream pressure of the filter medium of the filter device, or a temperature sensor for measuring the temperature of the oil. a plate-shaped substrate provided with a vibrator having a double spiral structure in which a first member and a second member formed by spirally winding a columnar member are provided opposite to each other; and a driving unit including a piezoelectric element provided on the first member, the viscosity sensor including the oil measuring device measuring the viscosity of the oil;
the plate-like substrate has a first conductive pattern connected to the piezoelectric element and a second conductive pattern provided adjacent to the vibrator,
The moisture-in-oil meter includes the second conductive pattern,
The measuring device according to claim 1 , wherein the second conductive pattern includes a capacitor having a pair of third and fourth conductive patterns disposed adjacent to each other. the housing has a cavity provided at the tip portion and a hole communicating the cavity with the outside of the housing,
The plate-shaped substrate is provided in the hollow portion,
The measuring device according to claim 5 , wherein the plate-like substrate is provided along a plane substantially perpendicular to a central axis of the tip portion. The moisture-in-oil meter has a flexible sheet member made of an organic material,
The measuring device according to claim 1 , wherein the sheet member includes a capacitor having a pair of fifth and sixth conductive patterns formed by carbonizing a surface of the sheet member. A measuring device according to any one of claims 1 to 7,
A control unit that calculates the electrical conductivity of the oil based on the measurement result of the oil moisture meter and determines the deterioration of the oil based on the electrical conductivity;
A diagnostic device comprising: A measuring device according to any one of claims 1 to 7,
A filter case including a substantially cylindrical case having an open upper end and a head provided on the case so as to cover the upper end of the case;
A filter element provided in the internal space of the filter case, the filter element having a cylindrical filter material;
Equipped with
The filter device, wherein the measuring device is provided on the filter case such that the tip portion is exposed to a space formed by the filter case and the filter element.

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