CN104458112B - Pressure detection device and intake pressure measurement device using the pressure detection device - Google Patents

Abstract

The invention provides a pressure detection device with a structure that the pressure value detected by a pressure sensor is not easily affected by the adhesion of moisture, and an air inlet pressure measuring device using the pressure detection device. In a pressure detection device (10) provided in an intake pressure measurement device, a detection space (15) surrounded by an outer wall portion (14) is formed in a housing (11), a sensor housing portion (17) is formed above the detection space (15), and a pressure sensor (21) is housed in the sensor housing portion (17). An escape space (18) is formed below the sensor housing section (17), and the escape space (18) is formed in an escape recess recessed rearward. Moisture entering the detection space (15) or moisture generated in the detection space (15) is guided to the retreat space (18), and the moisture can be prevented from adhering to the sensor housing section (17).

Description

Pressure detection device and intake pressure measurement device using the pressure detection device

technical field

The present invention relates to a pressure detection device and an intake pressure measurement device for detecting the intake pressure of an internal combustion engine using the pressure detection device.

Background technique

Patent Document 1 discloses an intake pressure measuring device for measuring an intake air amount of an internal combustion engine.

In this intake air pressure measuring device, an element portion as a pressure detecting device is provided inside an air chamber formed in a casing. A chip having a Si diaphragm is mounted on the element portion. An inlet hole is formed in the case, and intake pressure of the internal combustion engine is introduced into the air chamber through the inlet hole, and the pressure is detected by a chip mounted on the element portion. A convex portion serving as a weir is formed around the opening of the introduction hole in the housing.

When the intake pressure measuring device is used in winter or in a cold region, moisture condensed in the air chamber is blocked by the protrusion, and the moisture can be prevented from entering the inlet hole.

[Patent Document 1] Japanese Patent Laid-Open No. 2000-186969

In the intake air pressure measuring device described in Patent Document 1, a convex portion that prevents moisture from entering the inlet hole is formed on the housing side, but no countermeasure against moisture is taken in the element portion as the pressure detection device.

The element part described in FIG. 1 and FIG. 2 of Patent Document 1 has a structure in which a recess is formed on the surface and a chip for detecting a pressure signal is accommodated in the recess. Only the recessed part for housing the chip is formed in the element part, and the surface other than the recessed part is a flat surface. Since no measures are taken to guide the moisture adhering to the surface of the element portion to regions other than the concave portion, the moisture adhering to the element portion side tends to adhere to the surface of the chip in the concave portion.

In particular, in the technology described in Patent Document 1, the surface of the chip in the concave portion is arranged downward toward the direction of gravity, so moisture continues to accumulate on the surface of the chip until it grows to a size that can fall due to its own weight. Therefore, it is difficult to remove moisture adhering to the surface of the chip.

When moisture adheres to the chip, the mass of the moisture acts on the diaphragm of the chip, making it impossible to measure the intake air pressure accurately.

Contents of the invention

The present invention was made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a pressure detection device having a structure in which moisture does not easily adhere to a sensor housing portion in which a pressure sensor is housed, and an intake air pressure measurement device using the pressure detection device.

In the pressure detection device according to the present invention, a pressure sensor is held in a housing. The pressure detection device is characterized in that a detection space surrounded by an outer wall is formed in the housing, and the detection space is concavely formed inside. A sensor accommodating portion is formed in which the pressure sensor is accommodated, and a retreat space is formed in a region other than the sensor accommodating portion inside the detection space.

In the pressure detection device of the present invention, a concave sensor housing and a retreat space at a position deviated from the sensor housing are formed in the detection space surrounded by the outer wall. The moisture entering the detection space or the moisture generated in the internal space is easily transferred to the retreat space, and the possibility of the influence of the moisture directly acting on the pressure sensor accommodated in the sensor housing portion can be reduced.

In the present invention, the pressure sensor may be covered with an elastic body in the sensor housing portion. Furthermore, it is preferable that the surface of the elastic body is a concave curved surface, and the surface of the elastic body is formed up to the edge of the opening of the sensor housing part.

When the surface of the elastic body is a concave curved surface and the surface is formed to be continuous with the edge of the opening, the moisture adhering to the surface of the elastic body tends to flow into the retreat space, and the moisture is less likely to remain on the surface of the elastic body.

In the present invention, it is preferable that the retreat space is located on the lower side in the direction of gravity than the sensor housing portion.

Here, "the lower side toward the gravitational direction" refers to the lower side in the gravitational direction and the lower side in the gravitational direction. In the detection space surrounded by the outer wall portion, by arranging the retreat space below the sensor accommodating portion, moisture in the detection space can be guided to the retreat space.

In the present invention, the evacuation space may be formed in a evacuation recess that is recessed toward the rear relative to a front end portion of an inner wall portion that defines the evacuation space and the sensor housing portion.

In this case, it is preferable that the front end of the inner wall is positioned behind the front end of the outer wall.

By forming the above-mentioned evacuation recessed portion, moisture flowing from the surface of the sensor accommodating portion can be easily retained in the evacuation space.

Alternatively, in the present invention, a circuit arrangement portion is formed at a position deviated from the sensor accommodating portion of the housing, and the retreat space is formed in front of the circuit arrangement portion.

Furthermore, the intake air pressure measuring device of the present invention is characterized in that a frame for holding the pressure detection device is provided, and an intake air port for introducing the intake air pressure of the internal combustion engine into the detection space is formed on the frame. hole.

【Invention effect】

The present invention guides moisture entering or generated in the detection space to the retreat space in, for example, a pressure detection device mounted on an intake air pressure measurement device, thereby easily preventing moisture from directly adhering to the sensor housing.

Since the pressure detection device is provided with a countermeasure to evacuate moisture from the pressure sensor, it is easier to directly prevent moisture than the conventional technique of implementing a countermeasure to evacuate moisture to the housing of the intake pressure measuring device equipped with the pressure detection device. When reaching the sensor storage section where the pressure sensor is stored.

Therefore, it is difficult to cause false operation of pressure detection due to moisture, and high-precision pressure detection can be realized.

Description of drawings

FIG. 1 is a perspective view of a pressure detection device according to a first embodiment of the present invention.

Fig. 2 is a front view of the pressure detection device of the first embodiment.

3 is a cross-sectional view of the pressure detection device according to the first embodiment taken along line III-III in FIG. 2 , and is a cross-sectional view showing a state in which the pressure detection device is held by the housing of the intake pressure measurement device.

Fig. 4 is a front view of a pressure detection device according to a second embodiment of the present invention.

Fig. 5 is a cross-sectional view of the pressure detection device according to the second embodiment, taken along line V-V in Fig. 4 .

【Symbol Description】

1 Intake pressure measuring device

2 frames

4 Air intake holes

10 Pressure detection device

11 housing

12 terminal block

14 Outer wall

14a front end

15 Detection space

16 inner wall

16a front end

16b right end

16c left end

17 Sensor Storage Section

18 retreat space

21 pressure sensor

22 IC packages

23 elastomers

110 pressure detection device

111 shell

114 Outer wall

116 inner wall

117 Sensor Storage Section

118 retreat space

119 Circuit configuration department

detailed description

1 to 3 show a pressure detection device 10 according to a first embodiment of the present invention, and FIG. 3 shows a part of an intake air pressure measurement device 1 equipped with the pressure detection device 10 . In each drawing, the X1 direction is forward, the X2 direction is rearward, the Y1 direction is rightward, the Y2 direction is leftward, the Z1 direction is upward, and the Z2 direction is downward.

The intake air pressure measuring device 1 shown in FIG. 3 is attached to an internal combustion engine mounted on a motorcycle, and a pressure detecting device 10 and a throttle opening sensor are mounted together on a housing 2 . An intake pipe 3 is integrally formed on the housing 2 , and the intake pressure of the internal combustion engine is applied to the pressure detection device 10 from the intake hole 4 inside the intake pipe 3 .

As shown in FIGS. 1 to 3 , a housing 11 is provided in the pressure detection device 10 . The housing 11 is formed of PPS (polyphenylene sulfide) resin. Three terminal plates 12 and two plate portions 13 are embedded in the housing 11 . The terminal plate 12 and the plate portion 13 are copper plates.

The case 11, the terminal plate 12, and the plate portion 13 are integrated by so-called insert molding. In this forming method, terminal plates 12 are formed at fixed intervals on a first hoop material continuous in the Y direction, and on a second hoop material extending in the Y direction in parallel with the first hoop material. The plate portions 13 are formed at regular intervals. The terminal board 12 and the plate part 13 are set in the cavity of the molding die, and the molten resin of PPS is injected into the cavity to form the housing 11 and integrate the housing 11 , the terminal board 12 and the board part 13 . Thereafter, the terminal plate 12 and the plate portion 13 are respectively separated from the strip.

As shown in FIG. 1 , an outer wall portion 14 protruding forward (X1 direction) is integrally formed on the housing 11 . The outer wall portion 14 is formed in a cylindrical shape, and in the housing 11 , an inner region surrounded by the outer wall portion 14 serves as a detection space 15 . As shown in Figure 3, in the intake pressure measuring device 1, a printed wiring board 6 is arranged inside the frame body 2, and the terminal board 12 of the pressure detection device 10 passes through the through hole of the printed wiring board 6, and passes through the Solder fillet 7 is fixed to a land portion on the surface of printed wiring board 6 . Furthermore, the front end surface 14 a of the outer wall portion 14 is in close contact with the concave portion 5 on the inner surface of the frame body 2 , and the intake air pressure passing through the intake hole 4 is applied to the detection space 15 .

As shown in FIGS. 1 and 2 , an inner wall portion 16 is formed inside the detection space 15 . The front end surface 16 a of the inner wall portion 16 is set back toward the rear side (bottom side of the detection space 15 ) than the front end surface 14 a of the outer wall portion 14 . As shown in FIG. 2 , the inner wall portion 16 is formed by bending into a cylindrical shape, the right end portion 16 b is connected to the outer wall portion 14 , and the left end portion 16 c is continuous with the outer wall portion 14 . Between the right end portion 16b and the left end portion 16c (range α), the inner wall portion 16 and the outer wall portion 14 are integrated, and the actual inner wall portion 16 is limited to a region other than the range α, that is, the range β.

In the housing 11 , a sensor accommodating portion 17 is formed in a concave shape in a region surrounded by the inner wall portion 16 . As shown in FIG. 2 , the opening shape of the sensor housing portion 17 is circular when viewed from the front. As also shown in FIG. 3 , a pressure sensor 21 and an IC package 22 incorporating an integrated circuit (ASIC) are fixed to the bottom of the sensor housing portion 17 .

The pressure sensor 21 has a MEMS (Micro Electro Mechanical Systems) structure, and has a diaphragm receiving pressure, and a strain detection element such as a piezoresistive element or a piezoelectric element that detects deformation of the diaphragm. The integrated circuit in the IC package 22 incorporates an amplifier for amplifying the detection output from the pressure sensor 21 , a temperature sensor, a temperature compensation circuit for performing temperature compensation based on the temperature measured by the temperature sensor, and the like. The pressure sensor 21 and the IC package 22 are wired by wire bonding, and illustration of the wire bonding is omitted in each figure.

In the sensor housing portion 17, the IC package 22 is located on the upper side (Z1 side), and the pressure sensor 21 is located on the lower side (Z2 side). In the sensor housing portion 17 , the pressure sensor 21 is arranged at a position close to the inner surface of the inner wall portion 16 . On the center line O passing through the center of the pressure sensor 21, when the opening dimension of the sensor housing 17 is L1 and the distance between the pressure sensor 21 and the inner wall 16 is L2, the ratio (L2/L1) becomes 1/3 or less.

As shown in FIG. 3 , the pressure sensor 21 and the IC package 22 fixed to the bottom of the sensor housing portion 17 are covered with an elastic body 23 . The elastic body 23 is a gel-like viscoelastic body, such as a gel-like silicone resin or fluororesin. Since the elastic body 23 is formed by supplying a liquid resin material to the concave portion of the sensor accommodating portion 17 and then curing the resin material, the surface 23 a thereof becomes a concavely curved surface.

In the process of supplying and curing the liquid resin material to the inside of the sensor housing part 17, the surface of the resin material continues to the edge of the opening of the sensor housing part 17 (inside the front end surface 16a of the inner wall part 16) due to surface tension. edge or corner). Therefore, as shown in part E of FIG. 3 , the concavely curved surface 23 a of the elastic body 23 is formed continuously to the opening edge of the sensor housing part 17 (inner edge or corner of the front end surface 16 a of the inner wall part 16 ). That is, the front surface 23a and the front end surface 16a are continuous so that no step is formed at the boundary portion.

Therefore, the moisture adhering to the surface 23a of the elastic body 23 easily flows out toward the front end surface 16a.

Inside the detection space 15 of the casing 11 , a retreat space 18 is formed in a region other than the sensor housing portion 17 . As shown in FIG. 3 , the evacuation space 18 is formed in a evacuation recess recessed toward the rear (X2 direction) than the front end surface 16a of the inner wall portion 16 forming the sensor housing portion 17 (demarcating the sensor housing portion 17). As shown in FIG. 2 , the retreat space 18 is formed between the outer wall portion 14 and the inner wall portion 16 , and is formed in a range from a right end portion 16 b connecting the inner wall portion 16 and the outer wall portion 14 to a left end portion 16 c.

As shown in FIG. 2 , the range β from the right end 16 b to the left end 16 c of the inner wall 16 is formed within a range of 180 degrees or more relative to the center of the cylindrical inner wall 16 , that is, the center of the sensor housing 17 .

As shown in FIGS. 1 to 3 , when the intake air pressure measurement device 1 is installed in an internal combustion engine such as a motorcycle, in the pressure detection device 10, the terminal plate 12 is provided facing upward (towards the Z1 direction), and the outer wall portion In the detection space 15 surrounded by 14, the sensor housing part 17 is located on the upper side (Z1 side), and the retreat space 18 is located on the lower side (Z2 side) than the sensor housing part 17 toward the gravity side.

In the intake pressure measuring device 1 , the intake pressure of the internal combustion engine is introduced from the intake hole 4 of the housing 2 , and the intake pressure is applied to the detection space 15 of the pressure detection device 10 . The intake air pressure is detected by the pressure sensor 21 via the gel-like elastic body 23 , and the detected output is electrically processed by the integrated circuit in the IC package 22 .

Moisture contained in the intake air of the internal combustion engine, dew condensation due to a temperature difference, and the like may adhere to the inside of the detection space 15 . Since the surface 23a of the elastic body 23 is a concave curved surface, even if the moisture adheres to the surface 23a of the elastic body 23 of the sensor housing part 17, it will fall along the surface 23a due to its own weight, so that the moisture easily enters the retreat space 18. Since the surface 23a of the elastic body 23 is continuous with the front end 16a of the inner wall 16 without a difference in height, the moisture adhering to the surface 23a flows on the surface 23a to reach the front end 16a, and can be evacuated into the retreat space 18.

Furthermore, since the retreat space 18 is formed in the retreat recess recessed backward from the front end surface 16 a of the inner wall portion 16 , moisture entering the retreat space 18 does not flow back toward the surface 23 a of the elastic body 23 .

As shown in FIG. 2 , the retreat space 18 is formed in a range β of 180 degrees or more on the lower side of the cylindrical inner wall portion 16 . Therefore, a sufficiently large volume of the retreat space 18 in the detection space 15 can be ensured, so that moisture entering the detection space 15 or generated in the detection space 15 can easily stay in the lower area not in contact with the sensor housing portion 17 . As a result, moisture is less likely to adhere to the front surface 23a of the elastic body 23, and it is easy to prevent the pressure sensor 21 from being subjected to the pressure of moisture to cause an error in the pressure value that should be detected.

The pressure detecting device 110 according to the second embodiment of the present invention shown in FIGS. 4 and 5 is fixed in the housing 2 of the intake pressure measuring device 1 with the terminal board 112 facing downward. A cylindrical outer wall portion 114 is formed integrally with the casing 111 of the pressure detection device 110 facing forward, thereby forming a detection space 115 surrounded by the outer wall portion 114 .

A sensor accommodating portion 117 is formed in an upper portion of the detection space 115 . The sensor accommodating portion 117 is formed in a concave shape, and the pressure sensor 21 is fixed to the bottom of the sensor accommodating portion 117 . The sensor housing portion 117 is filled with a gel-like elastic body 23 covering the pressure sensor 21, and the surface 23a of the elastic body 23 is a concave curved surface. Also in this case, the surface 23a of the elastic body 23 is continuous with the front end surface 116a of the inner wall portion 116 due to surface tension without forming a level difference.

As shown in FIGS. 4 and 5 , a circuit arrangement portion 119 is formed on the housing 111 at a position that is lower than the sensor housing portion 117 in the direction of gravity. As shown in FIG. 5 , the circuit arrangement part 119 is formed in a concave shape at the bottom of the detection space 115 , and the IC package 22 is fixed to the bottom of the circuit arrangement part 119 . In addition, the concave portion in which the IC package 22 is accommodated is closed with the resin material 119b.

The front surface 119a of the circuit arrangement part 119 has a substantially planar shape. The front surface 119 a is located on substantially the same plane as the front end surface 116 a of the inner wall portion 116 defining the sensor housing portion 117 .

In the detection space 115 surrounded by the outer wall portion 114, the pressure sensor 21 is arranged above, and the circuit arrangement portion 119 in which the IC package 22 is housed is formed on the lower side. The area in front of the front is formed with a retreat space 118 with a large inner volume.

As shown in FIG. 5 , the retreat space 118 is formed within the range of the distance Lb from the lower edge of the sensor housing portion 117 to the lowermost end of the inner surface of the outer wall portion 114 . The ratio (Lc/La) of the distance Lc between the center of the pressure sensor 21 and the uppermost end of the inner surface of the outer wall portion 114 and the upper and lower opening dimensions La of the detection space 115 is 1/4 or less, and the ratio of the distance Lc to the distance Lb (Lc/Lb) is 1/3 or less.

In the pressure detection device 110 according to the second embodiment, the retreat space 118 with a large internal volume is formed in front of the circuit arrangement part 119 in which the IC package 22 is accommodated, so moisture entering the detection space 115 may The moisture generated at 115 is guided to the retreat space 118 , and the moisture is less likely to adhere to the front surface 23 a of the elastic body 23 .

Since only the pressure sensor 21 is housed in the sensor housing part 117, the area occupied by the sensor housing part 117 is reduced, and a retreat space with a large internal capacity is formed in a region other than the sensor housing part 117 inside the detection space 115. 118.

Moisture adhering to the sensor housing portion 117 flows from the concave curved surface of the surface 23a of the elastic body 23 to the front end portion 116a of the inner wall portion 116, and directly flows out into the retreat space 118, so the moisture is less likely to remain on the front surface 23a of the elastic body 23.

Therefore, it is easy to prevent the pressure value detected by the pressure sensor 21 from becoming an erroneous value due to the presence of moisture.

Claims (8)

1. A pressure detection device, which maintains a pressure sensor in the housing, The pressure detection device is characterized in that, A detection space surrounded by an outer wall portion is formed in the casing, a sensor storage portion is formed in a concave shape inside the detection space, and the pressure sensor is stored in the sensor storage portion, Inside the detection space, a retreat space is formed in a region other than the sensor housing portion, In the sensor housing part, the pressure sensor is covered with an elastic body, The surface of the elastic body is a concave curved surface, and the surface of the elastic body is formed to the edge of the opening of the sensor housing part, The retreat space is located on the lower side in the direction of gravity than the sensor housing portion, A surface of the elastic body is continuous with a front end surface of an inner wall portion defining the retreat space and the sensor housing portion without a difference in height. 2. The pressure detecting device according to claim 1, wherein, A circuit arrangement portion is formed at a position deviated from the sensor accommodating portion of the case, and the retreat space is formed in front of the circuit arrangement portion. 3. The pressure detection device according to claim 1, wherein, The retreat space is formed in a range of 180 degrees or more on the lower side of the inner wall portion, and the inner wall portion has a cylindrical shape. 4. A pressure detection device, which maintains a pressure sensor in the housing, The pressure detection device is characterized in that, A detection space surrounded by an outer wall portion is formed in the casing, a sensor storage portion is formed in a concave shape inside the detection space, and the pressure sensor is stored in the sensor storage portion, Inside the detection space, a retreat space is formed in a region other than the sensor housing portion, The evacuation space is formed in a evacuation recess in which a front end portion of an inner wall portion defining the evacuation space and the sensor housing portion is recessed toward the rear, In the sensor housing part, the pressure sensor is covered with an elastic body, The surface of the elastic body is a concave curved surface, and the surface of the elastic body is formed to the edge of the opening of the sensor housing part, The surface of the elastic body is continuous with the front end surface of the inner wall without a difference in height. 5. The pressure detection device according to claim 4, wherein, A front end portion of the inner wall portion is located behind a front end portion of the outer wall portion. 6. The pressure detecting device according to claim 4, wherein, A circuit arrangement portion is formed at a position deviated from the sensor accommodating portion of the case, and the retreat space is formed in front of the circuit arrangement portion. 7. The pressure detection device according to claim 4, wherein, The inner wall portion has a cylindrical shape, and the retreat space is formed in a range of 180 degrees or more on a lower side of the inner wall portion. 8. A device for measuring intake air pressure, characterized in that, A frame for holding the pressure detection device according to claim 1 is provided, and an air intake hole for introducing an intake air pressure of an internal combustion engine into the detection space is formed in the frame.