JP7369519B2 - Solenoid proportional valve and directional valve - Google Patents

Description

The present disclosure relates to electromagnetic proportional valves.

2. Description of the Related Art Electromagnetic proportional valves are known that adjust control pressure supplied to hydraulic equipment to be controlled according to excitation current applied to a solenoid coil. A conventional electromagnetic proportional valve includes a valve body that accommodates an axially movable spool, and a drive device that drives the spool. In such an electromagnetic proportional valve, by switching the position of the spool in the axial direction, a control pressure corresponding to the position of the spool can be supplied to the hydraulic equipment to be controlled.

The electromagnetic proportional valve is used as a pilot valve in a directional switching valve, as disclosed in Japanese Patent Laid-Open No. 2005-188707 (Patent Document 1). In the direction switching valve described in the publication, the spool position of the main spool is switched by control pressure supplied from an electromagnetic proportional valve.

Feedback control may be performed in which the stroke amount of the main spool of the directional switching valve is detected and the control pressure supplied from the electromagnetic proportional valve is controlled based on the detected stroke amount. A stroke sensor is used to detect the stroke amount of the main spool of the direction switching valve. Linear variable differential transformers (LVDTs) are widely used as stroke sensors.

Japanese Patent Application Publication No. 2005-188707

In order to detect the stroke amount of the main spool of the direction switching valve with a stroke sensor such as an LVDT, the stroke sensor and the main spool must be coaxially arranged. An electromagnetic proportional valve that supplies control pressure is also connected to the directional switching valve. Due to restrictions regarding the placement of the stroke sensor, it is considered that the electromagnetic proportional valve cannot be placed coaxially with the main spool. If the electromagnetic proportional valve is arranged at a position shifted in the radial direction from the axis of the main spool, the connecting block that connects the valve structure housing the main spool and the electromagnetic proportional valve becomes larger. Furthermore, in the connection block, the structure of the flow path for supplying pilot oil from the electromagnetic proportional valve to the valve structure becomes complicated. For example, in the device described in Patent Document 1, the connection block between the electromagnetic proportional valve and the valve structure includes a flow path extending in the axial direction of the main spool, a flow path extending in the horizontal direction, and a flow path extending in the inclined direction. A road is provided.

It is an objective of the present disclosure to alleviate or solve at least some of the conventional problems mentioned above. One specific objective of the present disclosure is to realize detection of the stroke amount of a valve structure operated by control pressure from an electromagnetic proportional valve using a simpler mechanism. One of the specific objects of the present disclosure is to connect an electromagnetic proportional valve and a valve structure operated by control pressure from the electromagnetic proportional valve to a measuring rod for detecting the stroke amount of a spool of the valve structure. They should be placed on the same axis. Other objects of the present disclosure will become apparent throughout the description.

An electromagnetic proportional valve according to an embodiment of the present invention has a through hole, and is disposed on one side of the through hole to face a counterpart member, and is arranged to face the counterpart member in response to an excitation current applied to a solenoid coil. and a control port for supplying a control pressure. The electromagnetic proportional valve further includes a measuring rod that moves through the through hole of the main body and moves in accordance with the stroke amount of the counterpart member, and is arranged to face the other side of the through hole of the main body, and the A stroke sensor that detects the stroke amount of the measurement rod.

In one embodiment of the invention, the body includes a spool that is moved by the excitation current applied to the solenoid coil and has the control port.

In one embodiment of the present invention, the other side of the through hole of the main body is arranged to face the stroke sensor.

In one embodiment of the invention, the through hole extends from one side of the body to the other side.

In one embodiment of the invention, the counterpart member is a valve structure.

An electromagnetic proportional valve according to an embodiment of the present invention includes a valve unit including a spool and a control port, and moves the spool in response to movement of a plunger driven by a solenoid coil to which an exciting current is applied, and the control port a drive device for supplying control pressure to the valve unit, and a main body having a through hole extending in the axial direction through the valve unit and the drive device. The electromagnetic proportional valve further includes a measuring rod that moves through the through hole of the main body according to a stroke amount of a mating member that faces one side of the main body in the axial direction, and a measuring rod that moves through the through hole of the main body in accordance with the stroke amount of a counterpart member that faces one side of the main body in the axial direction. and a stroke sensor that can be attached.

In one embodiment of the present invention, the drive device includes a drive unit and a drive unit housing that accommodates the drive unit, and the stroke sensor is provided in a sensor housing that is integrated with the drive unit housing.

A directional switching valve according to an embodiment of the present invention includes a valve unit including a spool and a control port, and moves the spool in response to movement of a plunger driven by a solenoid coil to which an excitation current is applied, and the control port a drive device that supplies control pressure to the valve unit, a main body having a through hole extending in the axial direction through the valve unit and the drive device, and a valve structure facing one side of the main body in the axial direction; A stroke sensor is provided on the other side of the main body in the axial direction, and has a measurement rod that moves through the through hole of the main body according to the stroke amount of the valve structure .

According to the embodiments of the present invention, detection of the stroke amount of the valve structure operated by the control pressure from the electromagnetic proportional valve can be realized with a simpler mechanism.

1 is a diagram schematically showing the appearance of an electromagnetic proportional valve according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the electromagnetic proportional valve of FIG. 1; In FIG. 2, the spool is in a neutral position. FIG. 2 is a longitudinal sectional view of the electromagnetic proportional valve of FIG. 1; In FIG. 3 , the spool is in the feeding position. FIG. 2 is a longitudinal sectional view of the electromagnetic proportional valve of FIG. 1; In Figure 4 , the spool is in the ejection position. FIG. 2 is a block diagram illustrating a directional switching valve including the electromagnetic proportional valve of FIG. 1. FIG. FIG. 6 is a block diagram illustrating a construction machine including the direction switching valve of FIG. 5. FIG.

Hereinafter, various embodiments of the present invention will be described with reference to the drawings as appropriate. Note that common constituent elements in the plurality of drawings are given the same reference numerals throughout the plurality of drawings. It should be noted that the drawings are not necessarily drawn to scale for illustrative purposes. In each drawing, some components may be omitted for convenience of explanation.

An electromagnetic proportional valve 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG. 1 is a diagram schematically showing the appearance of an electromagnetic proportional valve 1 according to an embodiment of the present invention, and FIGS. 2 to 4 are longitudinal cross-sectional views of the electromagnetic proportional valve 1.

As illustrated, the electromagnetic proportional valve 1 includes a main body 5. The main body 5 includes a drive device 10 and a valve unit 30. The drive device 10 and the valve unit 30 are arranged along the central axis A. In this specification, the direction along the central axis A is sometimes simply referred to as the "axial direction." In this specification, when referring to front and rear in the axial direction, the front and rear directions shown in FIGS. 1 to 4 are referred to, unless the context clearly dictates otherwise. Therefore, in the main body 5, the valve unit 30 is arranged in front of the drive device 10. The front end of the main body 5 faces the valve structure 2, and the rear end of the main body 5 faces the stroke amount detection unit 50. In this case, the valve structure 2, the electromagnetic proportional valve 1, and the stroke amount detection unit 50 are arranged coaxially (on the central axis A).

The valve unit 30 includes a hollow valve body 40 extending in the axial direction, and a spool 70 provided in the valve body 40 so as to be movable in the axial direction.

The electromagnetic proportional valve 1 is connected to a valve structure 2 operated by control pressure supplied from the electromagnetic proportional valve 1 through an oil passage (not shown). This oil passage is provided so as to extend along the central axis A within the connection block between the electromagnetic proportional valve 1 and the valve structure 2. The valve structure 2 includes a spool 2a. This spool 2a is provided in the valve structure 2 so as to be movable along the central axis A. The valve structure 2 has an oil chamber into which the control pressure output from the electromagnetic proportional valve 1 is introduced. The spool 2a of the valve structure 2 can be moved in the axial direction along the central axis A by the control pressure supplied from the electromagnetic proportional valve 1 to the oil chamber. One end of a measuring rod 91 is attached to the spool 2a. The measuring rod 91 axially penetrates the main body 5 of the electromagnetic proportional valve 1, as explained below.

A stroke amount detection unit 50 is provided at the rear of the main body 5 in the axial direction. In the illustrated embodiment, the stroke amount detection unit 50 includes a cup-shaped sensor housing 51 and a stroke sensor 52 provided within the sensor housing 51. In the illustrated embodiment, stroke sensor 52 is a linear variable differential transformer (LVDT). Differential transformers of types other than LVDTs can also be used as the stroke sensor 52.

The stroke sensor 52 includes an outer case 53 provided inside the sensor housing 51, an inner case 54 provided inside the outer case 53, a primary coil (not shown), and a set of secondary coils (not shown). ) and has. Both the outer case 53 and the inner case 54 have a cylindrical shape with a bottom and open toward the front in the axial direction. The primary coil and the secondary coil are held between an inner case 54 and an outer case 53, respectively. These coils are arranged along the central axis A in the order of a first secondary coil, a primary coil, and a second secondary coil.

A core 92 provided at the tip of a measuring rod 91 is arranged in an internal space inside the inner case 54 in the radial direction. The core 92 moves in the axial direction as the measuring rod 91 moves in the axial direction (that is, as the spool 2a moves in the axial direction). core 92
has a cylindrical shape. The core 92 is displaced together with the measurement rod 91 in the axial direction.
The core 92 is made of, for example, permalloy, electromagnetic soft iron, or other magnetic material.

The primary coil is energized by an alternating input voltage. The secondary coil is magnetically coupled to the primary coil via core 92. Therefore, when the primary coil is excited, an induced voltage is generated in the set of secondary coils.

In the stroke sensor 52, when the core 92 moves in the axial direction in response to the axial displacement of the spool 2a of the valve structure 2, the core 92 moves relative to the primary coil and the secondary coil. When the position of the core 92 with respect to the primary coil and a set of secondary coils changes while the primary coil is excited in the stroke sensor 52, an induced voltage generated in one of the set of secondary coils and an induced voltage in the other of the set of secondary coils change. Since the differential voltage that is the difference with the generated induced voltage changes, the position of the core 92 with respect to the reference position, that is, the stroke amount, is detected based on this differential voltage. The reference position of the core 92 is the position of the core 92 at the null point where the differential voltage becomes zero. Since the core 92 moves together with the spool 2a, the stroke amount of the spool 2a can be detected based on the differential voltage. The differential voltage is output to the controller .

The drive device 10 drives the spool 70 and controls the position of the spool 70 in the axial direction. The drive device 10 includes a hollow drive unit housing 11, a solenoid coil 23, a fixed core 24, a plunger 26, and a drive rod 27 provided in the plunger 26.

The drive unit housing 11 has a cylindrical shape extending along the central axis A direction. The drive unit housing 11 includes a peripheral wall 11a that partitions an internal space and an external space, a guide wall 11b provided on the radially inner side of the peripheral wall 11a, and a disk-shaped rear wall 11b provided at the rear end of the peripheral wall 11a in the axial direction. It has a wall 11c. The peripheral wall 11a has a cylindrical shape. The guide wall 11b has a cylindrical shape that is concentric with the peripheral wall 11a and has a smaller diameter than the peripheral wall 11a. The guide wall 11b is provided at a position spaced apart from the peripheral wall 11a in the radial direction. Thereby, a space is defined between the peripheral wall 11a and the guide wall 11b. A solenoid coil 23 is provided in the space between the peripheral wall 11a and the guide wall 11b. The rear wall 11c has a through hole 11d extending in the axial direction at its radial center. The through hole 11d may be referred to as a third through hole.

The drive unit housing 11 is hollow, and its internal space is open to the front and back of the drive unit housing 11. The front opening of the drive unit housing 11 is sealed by a fixed iron core 24 . The rear opening of the drive unit housing 11 is sealed by a position detector 50.

In the illustrated embodiment, the sensor housing 51 is a separate member from the drive housing 11. The sensor housing 51, which is a separate member from the drive unit housing 11, is assembled to the rear wall 11c of the drive unit housing 11. If it is not necessary to detect the stroke amount of the spool 2a, the through hole 11d of the drive unit housing 11 may be sealed with a plug member separate from the sensor housing 51. In this case, the electromagnetic proportional valve 1 does not include the stroke sensor 52. In other embodiments, the sensor housing 51 and the drive housing 11 may have an integral one-piece construction. In this case, the stroke sensor 52 is built into the electromagnetic proportional valve 1. In this way, the electromagnetic proportional valve 1 may be provided with the stroke sensor 52 or may not be provided with the stroke sensor 52.

Both the plunger 26 and the drive rod 27 are arranged on the central axis A in a cylindrical space defined by the guide wall 11b. Both the plunger 26 and the drive rod 27 are provided so as to be movable back and forth along the central axis A. Plunger 26 and drive rod 27 may have an integral one-piece construction. Drive rod 27 extends axially forward from plunger 26 . In the illustrated embodiment, drive rod 27 projects slightly axially rearwardly from plunger 26 . The drive rod 27 is a rod-shaped member that extends along the central axis A. The drive rod 27 has a through hole 27a extending in the axial direction. The through hole 27a extends in the axial direction on the same axis as the through hole 11d. For example, the through hole 27a and the through hole 11d both extend in the axial direction on the central axis A. The through hole 27a may be called a second through hole.

At least a portion of the plunger 26 is made of a magnetic material. At least a portion of the plunger 26 is disposed inside the solenoid coil 23 in the radial direction.

The internal space of the drive unit housing 11 is defined by a plunger 26 . Specifically, the internal section of the drive unit housing 11 includes a first solenoid chamber 14a located on the rear side of the plunger 26 in the axial direction, and a second solenoid chamber 14b located on the front side of the plunger 26 in the axial direction. , is divided into . The first solenoid chamber 14a and the second solenoid chamber 14b are connected by a first connection passage cp1 extending in the axial direction.

The solenoid coil 23 is excited based on a control signal input from a controller (not shown). The controller includes a processor that performs various calculation processes, a memory that stores various programs and data, and a device interface. The device interface is connected to the solenoid coil 23, the stroke sensor 52, and other devices. The controller drives the plunger 26 and the drive rod 27 by outputting a control signal (control pulse) to the solenoid coil 23, thereby switching the position of the spool 70. The controller 10 may control a control pressure output to a control port ap, which will be described later, based on a detection signal from the stroke sensor 52.

The fixed core 24 has a generally cylindrical shape. The fixed core 24 has a through hole extending in the axial direction at its radial center. A drive rod 27 is inserted into this through hole. The drive rod 27 can enter the internal space of the valve unit 30 from the fixed core 24 . The tip (front end) of the drive rod 27 is in contact with the base end (rear end) of the spool 70 .

The fixed iron core 24 has a second connection passage cp2 extending in the axial direction at a position shifted radially outward from the central axis A. The second connection channel cp2 is provided at a position facing the first connection channel cp1. The second solenoid chamber 14b and a preliminary chamber 41, which will be described later, are connected by a second connection flow path cp2.

Plunger 26 is driven by solenoid coil 23. That is, the plunger 26 can be moved in the axial direction by being driven by the solenoid coil 23. Specifically, when an excitation current is applied to the solenoid coil 23, the plunger 26 is attracted to the fixed iron core 24, thereby causing the plunger 26 and the drive rod 27 to move forward in the axial direction. When the drive rod 27 moves axially forward, the spool 70 is pushed axially forward by the drive rod 27 . In this way, the spool 70 is driven by the drive section including the solenoid coil 23, the fixed iron core 24, the plunger 26, and the drive rod 27. This drive unit can change the control pressure output to the control port ap by driving the spool 70 and moving its position in the axial direction.

Next, the valve unit 30 will be explained. As described above, the valve unit 30 includes the valve body 40 and the spool 70 movably provided on the valve body 40. The valve body 40 has a through hole 40a extending in the axial direction. The through hole 40a extends in the axial direction from the front end 40c of the valve body 40 to the rear end. The valve body 40 has a recess 40b in the radial center of the rear end. A preliminary chamber 41 is defined by the upper surface (rear surface) of the valve body 40 defining the recess 40b, the front surface of the fixed iron core 24, the drive rod 27, and the spool 70.

The valve body 40 has a pressure source port pp connected to the pressure source P, a tank port tp connected to the tank T, and a control port ap to which a control pressure is output. The control port ap is defined by a region near the front end of the through hole 40a. The control port ap is connected to the valve structure 2 to be controlled via a flow path (not shown). Control pressure supplied to the valve structure 2 is output to the control port ap.

The spool 70 has a shaft shape extending in the axial direction. The spool 70 is provided within the through hole 40a so as to be movable in the axial direction. The rear end of the spool 70 is in contact with the tip of the drive rod 27. The spool 70 has a through hole 70a extending along the central axis A. The through hole 70a extends in the axial direction from the front end 70b to the rear end 70c of the spool. The through hole 70a extends in the axial direction on the same axis as the through hole 11d and the through hole 27a. For example, the through hole 27a, the through hole 11d, and the through hole 70a all extend on the central axis A in the axial direction. The through hole 70a may be called a first through hole. In this way, the through hole 70a, the through hole 27a, and the through hole 11d penetrate each member of the main body 5 from the front to the rear in the axial direction on the central axis A. The through hole 70a, the through hole 27a, and the through hole 11d constitute a through hole that penetrates the main body 5 from its front end to its rear end. In this specification, a through hole that penetrates the main body 5 from its front end to its rear end may be referred to as a main through hole. Since the main through hole passes through the main body 5 from its front end to its rear end, the valve structure 2 is disposed facing the front end of the main through hole of the main body 5, and the stroke amount detection unit 50 is It is arranged opposite to the rear end of the main through hole No. 5. In other words, the main body 5 has a main through hole extending in the axial direction from its front end to its rear end. This main through hole includes a through hole 70a, a through hole 27a, and a through hole 11d. The main through-hole may include through-holes other than the through-hole 70a, the through-hole 27a, and the through-hole 11d. For example, in the section from the front end 40c of the valve body 40 to the front end 70b of the spool 70, a through section 40a of the valve body 40 exists. Since the through hole 40a extends in the axial direction on the central axis A, the main through hole may include a section of the through hole 40a from the front end 40c of the valve body 40 to the front end 70b of the spool 70.

The measurement rod 91 passes through the main body 5 through this main through hole. The measurement rod 91 protrudes from the front of the main body 5 and extends to the spool 2a of the valve structure 2, and also protrudes from the rear of the main body 5 and extends into the stroke sensor 52. Each of the through holes included in the main through hole has an inner diameter larger than the outer diameter of the measurement rod 91.

The spool 70 has a plurality of channels through which hydraulic oil flows. In the illustrated embodiment, the through hole 70a of the spool 70 defines a main flow path mp through which hydraulic oil flows. The main flow path mp extends from the front end 70b to the rear end 70c of the spool. Therefore, the main channel mp opens to the control port ap. The spool 70 also has a first branch channel bp1 and a second branch channel bp2 extending from the main channel mp to the outer surface of the spool 70. The spool 70 has a third connecting flow path cp3 that connects the main flow path mp and the preliminary chamber 41 near the rear end in the axial direction.

The valve unit 30 has a biasing member 80 disposed within the valve body 40. The biasing member 80 biases the spool 70 toward the drive rod 27. In other words, the biasing member 80 biases the spool 70 rearward along the central axis A. The biasing member 80 is, for example, a compression spring.

Due to the axial rearward biasing force received from the biasing member 80, the spool 70 is moved toward the drive rod 2.
I am in constant contact with 7. Therefore, when the drive rod 27 moves forward along the central axis A,
Due to the thrust from the drive rod 27, the spool 70 also moves forward along the central axis relative to the valve body 40. Conversely, when the drive rod 27 moves rearward along the central axis A, the spool 70 moves rearward along the central axis A while contacting the drive rod 27 due to the urging force from the urging member 80. The thrust force acting on the spool 70 from the drive rod 27 has a magnitude corresponding to the excitation current of the solenoid coil 23. Therefore, by adjusting the magnitude of the excitation current applied to the solenoid coil 23, the position of the spool 70 in the axial direction can be controlled.

The spool 70 is switched to at least one of a neutral position, a supply position, or a discharge position. Figure 2 shows the solenoid proportional valve 1 with the spool 70 in the neutral position, Figure 3 shows the solenoid proportional valve 1 with the spool 70 in the supply position, and Figure 4 shows the solenoid proportional valve 1 with the spool 70 in the discharge position. 1 is shown.

When spool 70 is in the neutral position shown in FIG. 2, each port pp, tp, ap is isolated from each other. In this case, hydraulic oil is not supplied to or discharged from the hydraulic equipment connected to the control port ap.

When the spool 70 is located in the supply position shown in FIG. It is cut off from pp and ap. Thereby, hydraulic oil is supplied from the pressure source P to the hydraulic equipment. Further, the control port ap is connected to the first solenoid chamber via the main flow path mp, the third connection flow path CP3, the preliminary chamber 41, the second connection flow path CP2, the second solenoid chamber 14b, and the first connection flow path CP1. 14a, so when the spool 70 is in the supply position, the first solenoid chamber 14a is maintained at the control pressure, which is the pressure of the hydraulic fluid in the control port ap. As a result, the pressure in the second solenoid chamber 14b in front of the plunger 26 and the pressure in the first solenoid chamber 14a in the rear become equal. That is, the first solenoid chamber 14a and the second solenoid chamber 14b have equal pressure.

When the spool 70 is in the discharge position shown in FIG. 4, the control port ap is connected to the tank port tp via the main flow path mp and the first branch flow path bp1, and the pressure source port pp It is blocked from ports tp and ap. As a result, oil is discharged from the hydraulic equipment to the tank T.

Next, the operation of the electromagnetic proportional valve 1 will be explained. When solenoid coil 23 is not energized, the biasing force of biasing member 80 maintains spool 70 in the ejection position shown in FIG. At this time, as described above, the flow path from the control port ap to the tank port tp via the main flow path mp of the spool 70 and the second branch flow path bp2 is opened. Therefore, oil is collected from the hydraulic equipment connected to the control port ap to the tank T connected to the tank port tp.

From this state, when the solenoid coil 23 is excited, the plunger 26 is driven, and the plunger 26 moves axially forward together with the drive rod 27 against the biasing force from the biasing member 80 . At this time, since the front end of the drive rod 27 is in contact with the spool 70, a forward thrust in the axial direction acts on the spool 70. This thrust causes the spool 70 to reach the neutral position shown in FIG. 2 from the discharge position. When the spool 70 is located at the neutral position, the connection between the first branch flow path bp1 and the pressure source port pp is cut off, and the connection between the second branch flow path bp2 and the tank port tp is also cut off. Therefore, when the spool 70 is located at the neutral position, oil is not discharged from the hydraulic equipment connected to the control port ap and no oil is supplied to the hydraulic equipment.

When a larger excitation current is applied to the solenoid coil 23, the plunger 26 and the drive rod 27 move further forward in the axial direction. This thrust received from drive rod 27 causes spool 70 to reach the feeding position shown in FIG. When the spool 70 is located at the supply position, a flow path from the control port ap to the pressure source port pp via the main flow path mp of the spool 70 and the first branch flow path bp1 is opened. Thereby, oil is supplied from the pressure source P connected to the pressure source port pp to the hydraulic equipment connected to the control port ap. The amount of oil supplied from the pressure source P to the hydraulic equipment when the spool 70 is located at the supply position is determined by the area where the first branch flow path bp1 and the pressure source port pp overlap, that is, the amount of oil supplied from the pressure source P to the hydraulic equipment. It changes depending on the amount of overlap with port pp. More specifically, as the excitation current flow increases, the amount of overlap between the first branch flow path bp1 and the pressure source port pp increases, and more oil flows from the pressure source port pp to the control port ap. Therefore, the greater the excitation current flow, the greater the control pressure output to the control port ap.

As described above, the control port ap is connected to the main flow path mp, the third connection flow path CP3, the preliminary chamber 41, the second connection flow path CP2, the second solenoid chamber 14b, and the first connection flow path CP1. 1 solenoid chamber 14a. Therefore, while the spool 70 is in the supply position, both the first solenoid chamber 14a and the second solenoid chamber 14b are maintained at the control pressure of the control port ap.

When the control pressure is output from the control port ap to the valve structure 2, the control pressure is introduced into the oil chamber of the valve structure 2. In the valve structure 2, the spool 2a moves along the axial direction by the control pressure. Since a measuring rod is attached to the spool 2a, the measuring rod 91 and core 92 also move in the axial direction as the spool 2a moves. Therefore, the measuring rod 91 moves in the axial direction according to the stroke amount of the spool 2a. The stroke amount of this core 92 is detected by the stroke sensor 52. The stroke amount detected by the stroke sensor 52 is output to the controller as a detection signal. The controller determines the stroke amount of the core 92 (equal to the stroke amount of the spool 2a) based on the detection signal obtained from the stroke sensor 52, and performs control according to the determined stroke amount.

Next, an example of an application of the electromagnetic proportional valve 1 will be described with reference to FIGS. 5 and 6. FIG. 5 is a block diagram illustrating the direction switching valve 100 including the electromagnetic proportional valve 1. As shown in FIG. As illustrated, the directional switching valve 100 includes an electromagnetic proportional valve 1 and a valve structure 2 operated by control pressure supplied from the electromagnetic proportional valve 1. The valve structure 2 includes a spool 2a, and adjusts the amount of hydraulic fluid supplied to a hydraulic cylinder (not shown) by switching the position of the spool 2a using the control pressure output from the electromagnetic proportional valve 1.

FIG. 6 is a block diagram illustrating a construction machine 200 including the direction switching valve 100. The construction machine 200 includes a direction switching valve 100. The construction machine is, for example, a hydraulic excavator operated by hydraulic pressure. Construction machine 200 includes various hydraulic cylinders. The hydraulic cylinders included in the construction machine 200 include a boom cylinder that drives a boom, an arm cylinder that drives an arm, a bucket cylinder that drives a bucket, and other hydraulic cylinders. The direction switching valve 100 controls the amount of hydraulic oil supplied to a hydraulic cylinder provided in the construction machine 200.

Next, the effects of the above embodiment will be explained. The electromagnetic proportional valve 1 according to the embodiment described above includes a main body 5 that extends in the axial direction from its front end to its rear end, and a control port ap provided at the front end of the main body 5. A control pressure supplied to the valve structure 2 to be controlled is output to the control port ap. The main body 5 has a main through hole extending in the axial direction from its front end to its rear end. This main through hole includes a through hole 70a, a through hole 27a, and a through hole 11d. The main through hole has an inner diameter through which a measuring rod 91 for detecting the stroke amount of the spool 2a of the valve structure 2 can pass. Thereby, the electromagnetic proportional valve 1 and the spool 2a driven by the electromagnetic proportional valve 1 can be arranged coaxially with the measuring rod 91. Thereby, the stroke amount of the spool 2a of the valve structure 2 operated by the control pressure from the electromagnetic proportional valve 1 can be detected using a simple mechanism in which each member is arranged on the same axis. Thereby, compared to the case where the potential proportional valve 1 is provided at a position shifted in the radial direction from the measurement rod 91, the connection block that connects the valve structure 2 and the electromagnetic proportional valve 1 can be made smaller.

In the embodiment described above, the main body 5 is arranged such that its front end faces the valve structure 2. Thereby, the control pressure output from the control port provided at the front end of the main body 5 can be easily introduced into the valve structure 2.

In the embodiment described above, the main body 5 has a drive housing 11 that houses a drive unit that drives the spool 70, and the stroke sensor is provided within the sensor housing 51 that is integrated with the drive housing 11. Thereby, the stroke sensor can be built into the electromagnetic proportional valve 1. Therefore, the stroke amount of the spool 2a of the valve structure 2 can be detected with a more compact mechanism.

The dimensions, materials, and arrangement of each component described herein are not limited to those explicitly described in the embodiments, and each component may be any number that may fall within the scope of the present invention. dimensions, materials, and arrangements. Further, components not explicitly described in this specification can be added to the described embodiments, or some of the components described in each embodiment can be omitted.

The specific shapes, arrangements, functions, and materials of the components of the drive device 10 and the valve unit 30 shown in this specification and the accompanying drawings are merely examples. The shape, arrangement, function, and material of each component of the drive device 10 and the valve unit 30 may be changed as appropriate without departing from the spirit of the present invention. For example, the drive device 10 may drive the drive rod so that the drive rod 27 moves rearward in the axial direction when the excitation current is applied to the solenoid coil 23 .

The valve structure 2 driven by the control pressure from the electromagnetic proportional valve 1 is not limited to the one illustrated in this specification. As the valve structure 2, various hydraulic devices including movable members that are moved by control pressure from the electromagnetic proportional valve 1 can be used.

1 Electromagnetic proportional valve 10 Drive device 11 Drive unit housing 14a First solenoid chamber 14a
14b Second solenoid chamber 14b
23 Solenoid coil 24 Fixed iron core 26 Plunger 27 Drive rod 30 Valve unit 40 Valve body 50 Stroke amount detection unit 52 Stroke sensor 70 Spool 80 Biasing member 91 Measuring rod 92 Core P Pressure source T Tank ap Control port pp Pressure source port tp Tank port mp Main flow path cp1 First connection flow path cp2 Second connection flow path cp3 Third connection flow path

Claims (8)

A through hole extending along the central axis, and an excitation current applied to the solenoid coil are arranged on one side of the through hole on the central axis so as to face a counterpart member on the central axis. a control port for supplying control pressure to the mating member in response;
a measurement rod that moves along the central axis through the through hole of the main body and moves according to the stroke amount of the counterpart member;
a stroke sensor that is arranged on the central axis to face the other side of the through hole of the main body and detects a stroke amount of the measurement rod;
A solenoid proportional valve. The electromagnetic proportional valve according to claim 1, wherein the main body includes a spool that moves by the exciting current applied to the solenoid coil. The electromagnetic proportional valve according to claim 1, wherein the through hole extends from one side of the main body to the other side. The electromagnetic proportional valve according to claim 1, wherein the counterpart member is a valve structure. A valve unit including a spool and a control port, and a drive device that moves the spool in response to movement of a plunger driven by a solenoid coil to which an excitation current is applied and supplies control pressure to the control port. , a main body having a through hole extending axially through the valve unit and the drive device;
a measuring rod that moves through the through hole of the main body according to a stroke amount of a counterpart member facing one side in the axial direction of the main body;
a stroke sensor attached to the other side of the main body in the axial direction;
A solenoid proportional valve. The drive device includes a drive section and a drive section housing that accommodates the drive section,
The electromagnetic proportional valve according to claim 5, wherein the stroke sensor is provided in a sensor housing that is integrated with the drive unit housing. The electromagnetic proportional valve according to claim 5 or 6, wherein the counterpart member is a valve structure. A valve unit including a spool and a control port, and a drive device that moves the spool in response to movement of a plunger driven by a solenoid coil to which an excitation current is applied and supplies control pressure to the control port. , a main body having a through hole extending axially through the valve unit and the drive device;
a valve structure facing one side of the main body in the axial direction;
a stroke sensor that has a measurement rod that moves through the through hole of the main body according to the stroke amount of the valve structure, and is attached to the other side of the main body in the axial direction;
A directional valve equipped with a.

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