Pressure Sensors for Evaporative Fuel Leak Detectors

Abstract

A pressure sensor (1) for an evaporative fuel leak detector is used to check for leaks in a fuel tank and a canister. The pressure sensor includes a sensor unit (2), a housing (3) and a sealing resin (4). The sensor unit (2) has a pressure receiving portion (21), a plurality of conductive terminals (213) and a molded resin portion (22). The housing has a fluid flow path (31) and a housing recess (32). Each remaining inner wall surface (323B) of the housing recess, except for the inner wall surface (323A) on the conductive terminal side, is provided with an inclined surface (327) and a vertical surface (328) in a cross section along an axial direction L perpendicular to a pressure receiving surface (210) of the sensor unit. The inclined surface is inclined inwardly as it moves toward the pressure receiving side L1. The vertical surface extends from an end portion on the pressure receiving side L1 of the inclined surface to define a filling gap (34) filled with sealing resin between a side surface (222) of the molded resin portion (22) and the vertical surface.

Description

Technical Field

[0001] The present disclosure relates to a pressure sensor for an evaporative fuel leak detector. Background Art

[0002] In a vehicle having an internal combustion engine, hydrocarbon fuels such as gasoline, high octane, and light oil used as liquid fuel in the internal combustion engine are stored in a fuel tank. Evaporated fuel is generated in the fuel tank. In order not to release the evaporated fuel to the outside, an evaporated fuel processing device having a canister capable of adsorbing the evaporated fuel is used.

[0003] In an evaporative fuel processing device, an evaporative fuel leak detector for checking the airtightness of a fuel tank and a canister is used. The evaporative fuel leak detector is provided with: a pressure reducing pump for reducing the pressure inside the fuel tank and inside the canister; a solenoid valve configured to switch the connection of the gas phase of the canister to the atmosphere or the pressure reducing pump; and a pressure sensor provided in a first pipe between the pressure reducing pump and the solenoid valve to detect the pressure in the first pipe reduced by the pressure reducing pump.

[0004] In addition, a bypass pipe is connected to the first pipe and the second pipe between the canister and the solenoid valve to bypass (or bypass) the solenoid valve so that a predetermined leakage state is formed by an orifice provided in the bypass pipe. Then, it is determined whether a fuel tank and a canister are leaking based on the leakage state from the orifice provided in the bypass pipe. The evaporative fuel leak detector is described in Patent Document 1, for example.

[0005] Prior art literature

[0006] Patent Literature

[0007] [Patent Document 1] JP 2015-169129A Summary of the invention

[0008] The pressure sensor shown in Patent Document 1 and the like includes a sensor unit having a pressure receiving portion, a housing, and a sealing resin, wherein a fluid flow path for accommodating a first pipe and a housing recess of the sensor unit are formed in the housing, and the sealing resin is arranged in a gap of the housing recess accommodating the sensor unit. The sensor unit is fixed to the housing recess, and the periphery of the sensor unit is sealed by the sealing resin, so that the pressure applied from the fluid flow path to the pressure receiving surface of the pressure receiving portion of the sensor unit is detected. The pressure receiving portion of the sensor unit converts the pressure applied to the pressure receiving surface into strain, and detects a voltage change caused by the strain.

[0009] Since the sealing resin arranged in the housing recess fixes the sensor unit to the housing, the sealing resin is arranged so as not to reach the rear side of the sensor unit on the opposite side of the pressure receiving surface of the pressure receiving portion. In addition, in a conventional pressure sensor, in order to guide the arrangement of the sensor unit into the housing recess and facilitate the injection of the sealing resin into the housing recess, an inclined surface is formed in the inner wall surface of the housing recess until a position facing the side surface of the sensor unit. The housing recess is filled with sealing resin along the inclined surface of the housing recess, and the thickness of the filling resin facing the side surface of the sensor unit becomes thinner as it goes toward the pressure receiving surface of the pressure receiving portion (i.e., toward the bottom side of the housing recess).

[0010] Due to such a structure of the sealing resin, when the pressure sensor is heated or cooled, the thermal stress applied from the sealing resin to the sensor unit increases as the thickness of the sealing resin increases. Since the thermal stress applied from the sealing resin to the sensor unit is non-uniform, the sensor unit may be deformed non-uniformly and stress is also generated in the pressure receiving portion, so that an error may occur in pressure detection of the pressure sensor.

[0011] The present disclosure has been made in view of the above-mentioned problems, and provides a pressure sensor for an evaporated fuel leak detector in which an error in pressure detection can be effectively reduced.

[0012] According to an example of the present disclosure, a pressure sensor is used for an evaporative fuel leak detector, which is configured to detect leakage of evaporative fuel in an evaporative fuel processing device, the evaporative fuel processing device including a fuel tank and a canister for adsorbing evaporative fuel discharged from the fuel tank. The pressure sensor includes a sensor unit, a housing, and a sealing resin. The sensor unit includes a pressure receiving portion configured to detect the pressure of a fluid applied to a pressure receiving surface, a plurality of conductive terminals arranged at the pressure receiving portion and made of a conductive material, and a molded resin portion covering the outer surface of the pressure receiving portion except the pressure receiving surface. The housing is provided with a fluid flow path and a housing recess, wherein a fluid is introduced to the pressure receiving surface through the fluid flow path, and the housing recess accommodates the sensor unit therein and is connected to the fluid flow path. The sealing resin is filled into the housing recess accommodating the sensor unit to cover the surface of the molded resin portion arranged in the housing recess. The shell has an annular inner wall surface that defines the shell recess and surrounds the side surface of the molded resin portion, and the annular inner wall surface of the shell includes a first inner wall surface and a plurality of second inner wall surfaces that intersect with each other, wherein the first inner wall surface is located on the conductive terminal side where a plurality of conductive terminals are arranged.

[0013] When the pressure receiving surface of the shell recess is arranged so that the direction exposed from the shell recess is the pressure receiving side and the direction opposite to the pressure receiving side of the shell recess is the rear side, in a cross section along a direction perpendicular to the pressure receiving surface, the second inner wall surface has an inclined surface inclined inwardly toward the pressure receiving side, and a vertical surface adjacent to the pressure receiving side of the inclined surface, and the vertical surface extends in a direction perpendicular to the pressure receiving surface to define a gap filled with sealing resin between the side surface of the molded resin portion and the vertical surface.

[0014] In the pressure sensor of the evaporative fuel leak detector according to the example, the sealing resin filled in the housing recess covers the surface of the molded resin portion arranged in the housing recess. With this configuration, electromagnetic noise or heat generated from the motor of the step-down pump and solenoid noise of the solenoid valve arranged around the pressure sensor of the step-down leak check module are difficult to reach the sensor unit from the rear side of the sensor unit.

[0015] In a cross section along the axial direction L perpendicular to the pressure receiving surface, each second inner wall surface of the housing recess of this example is provided with an inclined surface and a vertical surface. The inclined surface is inclined inwardly as it approaches the pressure receiving side. The vertical surface extends from the end of the pressure receiving side of the inclined surface to define a filling gap filled with sealing resin between the side surface of the molded resin portion and the vertical surface. With this configuration, the thickness of the sealing resin filled in the filling gap between the side surface of the molded resin portion and the vertical surface of the housing recess can be substantially uniform in the axial direction L.

[0016] Due to this structure of the sealing resin, when the pressure sensor is heated, the thermal stress applied from the sealing resin to the pressure receiving portion of the sensor unit becomes more uniform. Therefore, the pressure detection of the pressure receiving portion is less affected by the thermal stress.

[0017] Therefore, the pressure sensor of the evaporated fuel leak detector according to the present example can reduce the error of pressure detection and can improve the accuracy of pressure detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other objects, features and advantages of the present disclosure will be more clearly understood through the following detailed description with reference to the accompanying drawings.

[0019] Figure 1 is a diagram showing a configuration of a depressurization leak check module using a pressure sensor and an evaporated fuel processing device according to a first embodiment;

[0020] Figure 2 is a diagram showing the first embodiment of the present invention. Figure 4 A schematic cross-sectional view of a pressure sensor taken along cross section II-II;

[0021] Figure 3 is a diagram showing the first embodiment of the present invention. Figure 4 A schematic cross-sectional view of the pressure sensor taken at cross section III-III;

[0022] Figure 4 is a plan view showing the pressure sensor according to the first embodiment in a state where a sealing resin is not filled;

[0023] Figure 5 is a diagram showing the second embodiment of the present invention. Figure 7 A schematic cross-sectional view of the pressure sensor taken at a cross-section VV;

[0024] Figure 6 is a diagram showing the second embodiment of the present invention. Figure 7 A schematic cross-sectional view of the pressure sensor taken along cross section VI-VI;

[0025] Figure 7 is a plan view showing a pressure sensor according to a second embodiment in a state where a sealing resin is not filled;

[0026] Figure 8 is a diagram showing a method according to the second embodiment Figure 5 an enlarged view of a portion of;

[0027] Fig. 9 is an enlarged view showing another pressure sensor according to the second embodiment;

[0028] Fig.10 is an enlarged view showing another pressure sensor according to the second embodiment;

[0029] Fig.11 is a diagram showing the method according to the third embodiment. Fig.13 A schematic cross-sectional view of the pressure sensor taken along the cross section XI-XI;

[0030] Fig.12 is a diagram showing the method according to the third embodiment. Fig.13 A schematic cross-sectional view of the pressure sensor taken along the cross section XII-XII;

[0031] Fig.13 is a plan view showing a pressure sensor according to a third embodiment in a state where a sealing resin is not filled;

[0032] Fig.14 is a diagram showing a method according to the third embodiment Fig.11 an enlarged view of a portion of;

[0033] Fig.15 is a diagram showing the fourth embodiment of the present invention. Fig.17 A schematic cross-sectional view of the pressure sensor taken along the cross section XV-XV;

[0034] Fig.16 is a diagram showing the fourth embodiment of the present invention. Fig.17 A schematic cross-sectional view of the pressure sensor taken along the cross section XVI-XVI;

[0035] Fig.17 is a plan view showing a pressure sensor according to a fourth embodiment in a state where a sealing resin is not filled;

[0036] Fig.18 is a plan view showing the pressure sensor according to the fourth embodiment in a state where a sensor unit and a sealing resin are not filled. DETAILED DESCRIPTION

[0037] Preferred embodiments of the pressure sensor of the evaporated fuel leak detector will be described with reference to the accompanying drawings.

[0038] <First Embodiment>

[0039] like Figure 1 As shown, the pressure sensor 1 for the evaporated fuel leak detector of the present embodiment (hereinafter simply referred to as "pressure sensor 1") is used for the evaporated fuel processing device 6, which includes a fuel tank 61 and a canister 62 configured to adsorb evaporated fuel discharged from the fuel tank 61. The evaporated fuel leak detector detects the evaporated fuel leak in the device including the fuel tank 61 and the canister 62 by leak checking. In other words, the evaporated fuel leak detector is configured to determine whether there is a possibility of the evaporated fuel leak by using the leak check.

[0040] like Figures 2 to 4 As shown, the pressure sensor 1 includes a sensor unit 2, a housing 3 and a sealing resin 4. The sensor unit 2 includes: a pressure receiving portion 21 for detecting the pressure of a fluid R applied to a pressure receiving surface 210; and a mold resin portion 22 that covers the surface of the pressure receiving portion 21 other than the pressure receiving surface 210. The housing 3 includes a fluid flow path 31 for introducing the fluid R to the pressure receiving surface 210, and a housing recess 32 connected to the fluid flow path 31. The sensor unit 2 is accommodated in the housing recess 32 of the housing 3. The sealing resin 4 is arranged in the housing recess 32 and is configured to cover at least a rear surface 223 of the mold resin portion 22 located on the opposite side of the pressure receiving surface 210.

[0041] The pressure sensor 1 of this embodiment will be described in detail below. The step-down leak check module 10 will now be described.

[0042] like Figure 1 As shown, the pressure sensor 1 is attached to the vehicle evaporative fuel treatment device 6 having the fuel tank 61 and the canister 62, and is a part of the depressurization leak check module (ELCM) 10, which is configured as an evaporative fuel leak detector to check for leaks in the fuel tank 61 and the canister 62. The depressurization leak check module 10 is provided with: a depressurization pump 51 for depressurizing the inside of the fuel tank 61 and the inside of the canister 62 to a depressurized state; a solenoid valve 52 configured to switch the connection of the canister 62 to be connected to the atmospheric pipe 55 open to the atmosphere or to the depressurization pump 51; and a pressure sensor 1, which is configured to detect the pressure in the first pipe 53A. The inside of the first pipe 53A is depressurized by the depressurization pump 51.

[0043] The pressure reducing pump 51, the solenoid valve 52, the pressure sensor 1, etc. are electrically connected to the controller 8. The pressure sensor 1 is arranged in a first pipe 53A connecting the pressure reducing pump 51 and the solenoid valve 52. The canister 62 and the solenoid valve 52 are connected through a second pipe 53B. A bypass pipe 54 bypassing the solenoid valve 52 is connected to the first pipe 53A and the second pipe 53B. An orifice 541 is provided in the bypass pipe 54.

[0044] The fuel tank 61 and the canister 62 are connected through a vapor pipe 63, and the evaporated fuel is discharged through the vapor pipe 63. The vapor pipe 63 may be provided with a sealing valve 631, and when the evaporated fuel in the fuel tank 61 is discharged to the canister 62, the sealing valve 631 opens the vapor pipe 63. The canister 62 and the intake pipe 71 of the engine (internal combustion engine) 7 are connected through a purge pipe 64. A purge valve 641 is provided in the purge pipe 64. When the fuel components are discharged from the canister 62 to the intake pipe 71, the purge valve 641 opens the purge pipe 64.

[0045] The pressure reducing pump 51 is also called a vacuum pump, and can evacuate the canister 62, the fuel tank 61, the first pipe 53A, the second pipe 53B, and the bypass pipe 54. When the fuel tank 61, the canister 62, etc. are evacuated by the pressure reducing pump 51, the discharge valve 641 of the discharge pipe 64 is closed.

[0046] The solenoid valve 52 is made of an electromagnetic valve. The solenoid valve 52 can be switched between an open position 521 that opens the interior of the canister 62 to the atmosphere and a pressure reducing position 522 that connects the interior of the canister 62 to the pressure reducing pump 51. When the solenoid valve 52 is switched to the pressure reducing position 522, the first pipe 53A and the second pipe 53B are connected to each other via the solenoid valve 52, so that the first pipe 53A, the second pipe 53B and the bypass pipe 54 are connected to each other.

[0047] The orifice 541 provided in the bypass pipe 54 is used to simulate a predetermined leakage state, which indicates the upper limit value of the permissible range of leakage in the path of the air pumped by the pressure reducing pump 51. The orifice 541 of the present embodiment simulates the state of forming a hole with a diameter of 0.5 mm in the path of the air pumping. When a pseudo-leakage state is formed by the orifice 541, the solenoid valve 52 is in the open position 521, and the path circulating from the pressure reducing pump 51 through the first pipe 53A, the solenoid valve 52 and the bypass pipe 54 passing through the orifice 541 is evacuated. Therefore, the pressure is detected by the pressure sensor 1. In this state, the pressure detected by the pressure sensor 1 becomes the pressure of the leakage allowable reference value.

[0048] On the other hand, when leak detection is performed, the solenoid valve 52 is located at the pressure reducing position 522, so that the pressure reducing pump 51 evacuates the inside of the fuel tank 61, the canister 62, etc. At this time, if the pressure detected by the pressure sensor 1 is equal to or less than the leakage allowable reference value, it is determined that there is no leakage, and if the pressure detected by the pressure sensor 1 exceeds the leakage allowable reference value, it is determined that there is a leakage.

[0049] The solenoid valve 52 is normally located in the open position 521 , and the interior of the canister 62 can be maintained at atmospheric pressure under normal conditions.

[0050] Next, the evaporated fuel processing device 6 will be described.

[0051] like Figure 1 As shown, in the vehicle, the evaporated fuel processing device 6 is used so that the evaporated fuel as a part of the gas in the fuel tank 61 is not released into the atmosphere. The evaporated fuel in the fuel tank 61 is stored in the canister 62 and then discharged to the intake pipe 71 of the engine 7, or bypasses the canister 62 and is discharged to the intake pipe 71 of the engine 7. Then, the fuel component of the evaporated fuel is used for combustion in the engine 7.

[0052] The flow rate of combustion air A supplied from the intake pipe 71 to the engine 7 is adjusted by operating a throttle valve 72 arranged in the intake pipe 71. The engine 7 is provided with a fuel injection device (not shown) that injects fuel F supplied from the fuel tank 61.

[0053] Next, the fuel tank 61 will be described.

[0054] like Figure 1 As shown, the fuel tank 61 stores the fuel F used for the combustion operation of the engine 7. The fuel tank 61 includes a fuel supply port 611, a vapor port 612, and a fuel pump (not shown). The fuel supply port 611 is used to receive the fuel F filled into the fuel tank 61 from the outside. The vapor port 612 is connected to the vapor pipe 63. The fuel pump is used when supplying the fuel F to the fuel injection device of the engine 7. The fuel pump supplies the liquid-phase fuel F of the fuel tank 61 to the fuel injection device.

[0055] The fuel cap 613 is provided at the fuel supply port 611 of the fuel tank 61, and closes the fuel supply port 611 during normal operation. The fuel cap 613 is removed during refueling to open the fuel supply port 611. In addition, the vehicle is provided with a fuel lid (not shown) that covers the fuel cap 613 during normal operation. The fuel lid enables an operation of removing / attaching the fuel cap 613 during refueling.

[0056] The canister 62 will be described.

[0057] like Figure 1 As shown, the canister 62 includes a canister housing 621 and an adsorbent 622 such as activated carbon. The adsorbent 622 is disposed in the canister housing 621 and adsorbs evaporated fuel (i.e., fuel vapor). The canister housing 621 of the canister 62 includes an inlet 623, an outlet 624, and a pressure release port 625. The inlet 623 is connected to the vapor pipe 63 and allows gas to enter. The outlet 624 is connected to the drain pipe 64 and allows fuel components to leave. The pressure release port 625 is connected to the second pipe 53B and the solenoid valve 52 so as to open to the atmosphere. When the evaporated fuel (i.e., gaseous fuel) is discharged from the gas phase of the fuel tank 61 to the canister 62, and when the solenoid valve 52 is in the open position 521, the pressure release port 625 is opened to the atmosphere through the atmospheric pipe 55. In the canister 62, the fuel component in the evaporated fuel is adsorbed by the adsorbent 622, and the pressure in the canister 62 becomes equal to the atmospheric pressure.

[0058] The fuel components adsorbed by the adsorbent 622 of the canister 62 pass through the purge pipe 64 and are discharged to the intake pipe 71 of the engine 7. At this time, the solenoid valve 52 is in the open position 521, the pressure release port 625 of the canister 62 is opened to the atmosphere, and the purge pipe 64 is opened by the purge valve 641. The fuel components adsorbed by the adsorbent 622 are discharged to the intake pipe 71 of the engine 7 by the airflow caused by the pressure difference between the pressure of the atmosphere entering the canister 62 through the pressure release port 625 and the negative pressure in the intake pipe 71.

[0059] Next, the sensor unit 2 of the pressure sensor 1 will be described.

[0060] like Figure 2 and Figure 3 As shown, the pressure receiving portion 21 of the sensor unit 2 is constructed by using a piezoresistive semiconductor. The piezoresistive semiconductor utilizes the piezoresistive effect, which is a phenomenon in which resistance changes when a substance is subjected to stress. The pressure receiving portion 21 includes a circuit portion 211 and an insulating gel 212 surrounding the circuit portion 211, and a detection circuit such as a Wheatstone bridge is formed in the circuit portion 211. The sensor terminal is led out from the circuit portion 211 to the outside of the gel 212 and the molding resin.

[0061] In the present embodiment, in the axial direction L of the housing 3, the side where the pressure receiving surface 210 of the pressure receiving portion 21 is located is referred to as the pressure receiving side L1, and the side opposite to the pressure receiving surface 210 is referred to as the rear side L2. In other words, the side of the housing recess 32 where the pressure receiving surface 210 of the pressure receiving portion 21 is arranged is referred to as the pressure receiving side L1, and the side of the housing recess 32 opposite to the pressure receiving side L1 is referred to as the rear side L2.

[0062] The molded resin portion 22 of the sensor unit 2 is made of a thermoplastic resin or the like having excellent heat resistance. The pressure receiving surface 210 of the pressure receiving portion 21 is formed as a front surface of the pressure receiving portion 21, which is not covered by the molded resin portion 22. The pressure receiving surface 210 is located at a position recessed toward the rear side L2 from the surface of the molded resin portion 22. The molded resin portion 22 covers a portion of the pressure receiving portion 21 except for the front surface where the pressure receiving surface 210 is located.

[0063] like Figure 2 and 3 As shown, the molded resin portion 22 of the present embodiment includes a noise removal capacitor 23, which is configured to remove noise (electromagnetic noise) that affects the pressure detection of the sensor unit 2. The capacitor 23 is made of a single ceramic capacitor or the like in which a plurality of electrodes and a dielectric are laminated. The capacitor 23 has a characteristic of blocking a direct current while allowing an alternating current to pass. The capacitor 23 is configured to remove an alternating current component superimposed on the circuit unit 211 by grounding the circuit portion 211 of the pressure receiving portion 21 or the like. The wiring of the circuit unit 211, the capacitor 23, etc. is electrically connected to a plurality of conductive terminals 213.

[0064] Next, the housing 3 of the pressure sensor 1 will be described in detail.

[0065] like Figure 2 and Figure 3 As shown, the housing 3 of the pressure sensor 1 accommodates the sensor unit 2 and is configured to introduce the fluid R into the pressure receiving portion 21 of the sensor unit 2. The housing 3 is provided in the depressurization leakage inspection module 10, as shown in FIG. Figure 1 As shown, the depressurization leakage check module 10 includes a depressurization pump 51, a solenoid valve 52, etc. The fluid flow path 31 of the housing 3 is formed along the axial direction L of the housing 3. The axial direction L of the housing 3 is a direction perpendicular to the pressure receiving surface 210 of the pressure receiving portion 21 of the sensor unit 2. The pressure of the fluid R flowing through the fluid flow path 31 is vertically applied from the fluid flow path 31 to the pressure receiving surface 210 of the pressure receiving portion 21.

[0066] The housing recess 32 of the case 3 is formed to a size that accommodates the sensor unit 2. The housing recess 32 has a fitting portion 321 into which the pressure receiving portion 222A of the molded resin portion 22 of the sensor unit 2 is fitted, and a filling portion 322 connected to the fitting portion 321 to be filled with the sealing resin 4. In addition, an expanded flow path portion 311 is formed between the fitting portion 321 and the fluid flow path 31, in which the flow of the fluid R flowing from the fluid flow path 31 to the pressure receiving surface 210 of the pressure receiving portion 21 is expanded.

[0067] The pressure receiving portion 222A positioned on the side surface 222 of the molded resin portion 22, closer to the side where the pressure receiving surface 210 is located, is fitted into the fitting portion 321 of the housing recess 32. Because the molded resin portion 22 of the sensor unit 2 is fitted into the fitting portion 321, when the sealing resin 4 is filled in the filling portion 322 of the housing recess 32, the sealing resin 4 is prevented from entering the fluid flow path 31.

[0068] like Figure 3 and Figure 4 As shown, the inner wall surface 323 of the filling portion 322 defining the housing recess 32 is made of an inner wall surface 323A on the conductive terminal side and a remaining inner wall surface 323B other than the inner wall surface 323A on the conductive terminal side. The inner wall surface 323A on the conductive terminal side is arranged in one direction of the housing recess 32 in a plane parallel to the pressure receiving surface 210 of the pressure receiving portion 21, and the remaining inner wall surface 323B is arranged in the remaining three directions in the plane. At the end of the pressure receiving side L1 of the inner wall surface 323A on the conductive terminal side, a bottom surface 324 parallel to the pressure receiving surface 210 is formed in a cross section along the axial direction L perpendicular to the pressure receiving surface 210. As shown in FIG. Figure 3 As shown, the bottom surface 324 is located between the side surface 222 of the molded resin portion 22 of the sensor unit 2 and the inner wall surface 323A on the conductive terminal side.

[0069] The housing 3 is provided with a plurality of housing side terminals 33, which are in contact with and conduct electricity with the plurality of conductive terminals 213. The plurality of conductive terminals 213 of the pressure receiving portion 21 of the sensor unit 2 are electrically connected to a power source, a controller 8, etc. arranged outside the step-down leakage check module 10 via the plurality of housing side terminals 33.

[0070] like Figure 4 As shown in FIG. 1 , in the molded resin portion 22 of the sensor unit 2, chamfered portions 225 or curved surface portions 226 are formed at four corner portions in a plane parallel to the pressure receiving surface 210 of the pressure receiving portion 21. The inner wall surface 323 of the housing recess 32 of the housing 3 is formed in a shape corresponding to the shape of the sensor unit 2 in a plane parallel to the pressure receiving surface 210. Chamfered portions 323C or curved surface portions 323D are formed at corner portions of three remaining inner wall surfaces 323B on the inner wall surface 323 in a plane parallel to the pressure receiving surface 210. The remaining inner wall surface 323B is provided with the chamfered portion 323C and the curved surface portion 323D.

[0071] The sealing resin 4 will be described.

[0072] like Figure 2 and 3As shown, the sealing resin 4 is made of a thermosetting resin such as epoxy resin. The sealing resin 4 is used to fix the sensor unit 2 to the housing 3 and to seal the periphery of the sensor unit 2. After the sensor unit 2 is assembled in the assembly portion 321 of the housing recess 32 of the housing 3, the sealing resin 4 is filled in the filling portion 322 of the housing recess 32. The sensor unit 2 is completely covered with the sealing resin 4 filled in the filling portion 322 of the housing recess 32. In other words, when the sensor unit 2 is arranged in the housing recess 32, the molded resin portion 22 of the sensor unit 2 is exposed in the filling portion 322 of the housing recess 32, and then the surface of the molded resin portion 22 is covered and sealed by the sealing resin 4.

[0073] The sealing resin 4 is filled in the filling portion 322 of the housing recess 32 to cover the rear side portion 222B and the entire rear surface 223 of the side surface 222 of the molded resin portion 22 of the sensor unit 2 except for the pressure receiving side portion 222A. With this configuration, electromagnetic noise, heat, and the like generated from the equipment arranged around the pressure sensor 1 are difficult to reach the pressure receiving portion 21 of the sensor unit 2.

[0074] The material of the pressure sensor 1 will be described.

[0075] In a comparative pressure sensor, the rear surface of the sensor unit is exposed to the outside without being covered by a sealing resin. In this comparative pressure sensor, there may be two factors that make it difficult to ensure airtightness: peeling at the interface between the molded resin portion of the sensor unit and the sealing resin, and peeling at the interface between the housing and the sealing resin. In addition, peeling can easily occur due to these two types of interfaces.

[0076] like Figure 2 and Figure 3 As shown, in the vicinity of the sensor unit 2 of the pressure sensor 1 of the present embodiment, since the sealing resin 4 covers and seals the entire molded resin portion 22, the interface between the molded resin portion 22 and the sealing resin 4 is not exposed to the outside around the sensor unit 2. In this case, only the interface between the housing 3 and the sealing resin 4 is exposed to the outside around the sensor unit 2. Therefore, the factor for ensuring the airtightness of the pressure sensor 1 due to peeling is only the interface between the housing 3 and the sealing resin 4.

[0077] In the present embodiment, since the capacitor 23 is incorporated into the molded resin portion 22, a resin material having a small linear expansion coefficient is intentionally used so as to be close to the linear expansion coefficient of the capacitor 23. In addition, the sealing resin 4 of the present embodiment is prepared by adding a filler as an inorganic material to a curable resin material, thereby intentionally reducing the linear expansion coefficient. In other words, the sealing resin 4 of the present embodiment contains a curable resin material and a filler as an inorganic material added to the resin material. The filler content in the sealing resin 4 is in the range of 40% to 90%.

[0078] When the content ratio of the filler in the sealing resin 4 increases, the linear expansion coefficient becomes lower. For example, when the mass content of the filler in the sealing resin 4 is 40% or more, the linear expansion coefficient can be effectively reduced. On the other hand, if the mass content of the filler in the sealing resin 4 exceeds 90%, the content of the filler becomes too large, and the adhesiveness of the sealing resin 4 may deteriorate.

[0079] (Functions and Effects)

[0080] The pressure sensor 1 of the vaporized fuel leak detector of the present embodiment is used for the step-down leak check module 10. In the pressure sensor 1, the sealing resin 4 arranged in the housing recess 32 covers the rear side portion 222B of the side surface 222 of the molded resin portion 22 of the sensor unit 2 and all of the rear surface 223 of the molded resin portion 22. With this configuration, it is difficult for the electromagnetic noise generated from the motor of the step-down pump 51 and the solenoid noise of the solenoid valve 52 arranged around the pressure sensor 1 of the step-down leak check module 10 to reach the sensor unit 2 from the rear side L2 of the sensor unit 2. In addition, it is possible to prevent the heat generated from the motor of the step-down pump 51, the solenoid of the solenoid valve 52, etc. from reaching the sensor unit 2 from the rear side L2 of the sensor unit 2. Therefore, the pressure sensor 1 is less susceptible to the influence of the electromagnetic noise and the heat, and the factors causing the detection error in the pressure sensor 1 can be effectively reduced.

[0081] Therefore, according to the pressure sensor 1 of the evaporated fuel leak detector of the present embodiment, it is possible to improve the pressure detection accuracy.

[0082] <Second Embodiment>

[0083] The pressure sensor 1 of this embodiment is different from the pressure sensor 1 of the first embodiment, especially the shape of the housing 3. Figures 5 to 7As shown, the pressure sensor 1 of the second embodiment also includes a sensor unit 2, a housing 3, and a sealing resin 4. The sensor unit 2 includes a pressure receiving portion 21 configured to detect the pressure of a fluid R applied to a pressure receiving surface 210, a plurality of conductive terminals 213 provided at the pressure receiving portion 21 and made of a conductive material, and a molded resin portion 22 covering the outer surface of the pressure receiving portion 21 except the pressure receiving surface 210. The basic configuration of the housing 3 and the sealing resin 4 is similar to that of the first embodiment, and the explanation of the same parts is partially or entirely omitted.

[0084] The annular inner wall surface 323 surrounding the side surface 222 of the molded resin portion 22 and defining the housing recess 32 is made of a conductive terminal side inner wall surface 323A and a remaining inner wall surface 323B, similar to the structure of the first embodiment. When the remaining inner wall surface 323B is viewed in a cross section along the axial direction L perpendicular to the pressure receiving surface 210, the remaining inner wall surface 323B is provided with a parallel step surface 326 parallel to the pressure receiving surface 210, as shown in FIG. Figure 8 shown.

[0085] like Figure 8 As shown, the parallel step surface 326 is configured to prevent the peeling occurring at the exposed position of the rear side L2 of the interface between the remaining inner wall surface 323B of the housing recess 32 and the sealing resin 4 from further extending to the pressure receiving side L1. Figure 7 and Figure 8 As shown, parallel step surfaces 326 are formed on the remaining inner wall surfaces 323B arranged in three directions in a plane parallel to the pressure receiving surface 210 in the inner wall surface 323 of the housing recess 32. The parallel step surfaces 326 of each remaining inner wall surface 323B are formed parallel to the pressure receiving surface 210.

[0086] like Figure 5 and Figure 6 As shown, all the parallel step surfaces 326 of each remaining inner wall surface 323B are positioned on the rear side L2 compared to the tip end of the rear surface 223 positioned on the rear side L2 in the molded resin portion 22. In addition, the sealing resin 4 is filled to a position exceeding the parallel step surfaces 326 of each remaining inner wall surface 323B in the case recess 32 up to the rear side L2. In other words, the surface 41 of the rear side L2 of the sealing resin 4 exceeds the parallel step surfaces 326 of each remaining inner wall surface 323B on the rear side L2.

[0087] The thickness of the sealing resin 4 arranged on the rear side L2 of the molded resin portion 22 can be made equal to or greater than a specific thickness by filling the sealing resin 4 to a position beyond the parallel step surface 326 on the rear side L2. If the parallel step surface 326 is used as a mark of the filling position of the sealing resin 4 and the entire parallel step surface 326 is buried in the sealing resin 4, the thickness of the sealing resin 4 can be set to a specific thickness or greater.

[0088] like Figure 8 As shown, in the cross section along the axial direction L perpendicular to the pressure receiving surface 210, the remaining inner wall surface 323B of the present embodiment is provided with a first vertical surface 325, a parallel step surface 326, an inclined surface 327, and a second vertical surface 328 in order from the opening side of the housing recess 32. The opening side of the housing recess 32 corresponds to the rear side L2 in the axial direction L. The first vertical surface 325 is located on the rearmost side L2 of each remaining inner wall surface 323B and is formed perpendicular to the pressure receiving surface 210. The parallel step surface 326 is formed adjacent to the end of the pressure receiving side L1 of the first vertical surface 325 in each remaining inner wall surface 323B.

[0089] The inclined surface 327 is formed adjacent to the end of the parallel step surface 326 of each remaining inner wall surface 323B and is located inwardly toward the pressure receiving side L1, as shown in FIG. Figure 8 As shown. Inward means the center side of the housing recess 32 in the plane of the pressure receiving surface 210. When the sensor unit 2 is fitted into the fitting portion 321 of the housing recess 32, the inclined surface 327 serves as a guide surface. The inclined surface 327 can be formed in a short range, such as Figure 8 As shown, or may be formed to appropriately guide the size of the assembly of the sensor unit 2, such as Fig. 9 shown.

[0090] like Figure 8 and Fig. 9 As shown, in each of the remaining inner wall surfaces 323B, a second vertical surface 328 is formed perpendicular to the pressure receiving surface 210, adjacent to the end of the pressure receiving side L1 of the inclined surface 327. The second vertical surface 328 is provided to define a filling gap 34 filled with the sealing resin 4 between the second vertical surface 328 and the side surface 222 of the molded resin portion 22. In other words, the filling gap 34 filled with the sealing resin 4 is formed between the second vertical surface 328 and the side surface 222 of the molded resin portion 22. In addition, as Figure 6 As shown, the inner wall surface 323A on the conductive terminal side is formed, for example, perpendicular to the pressure receiving surface 210 without a step portion.

[0091] (Functions and Effects)

[0092] In the pressure sensor 1 of the evaporated fuel leak detector of the present embodiment, the sealing resin 4 filled in the housing recess 32 covers the surface portion of the molded resin portion 22 arranged in the housing recess 32. That is, the sealing resin 4 completely covers the rear side portion 222B of the side surface 222 of the molded resin portion 22 and the rear surface 223 of the molded resin portion 22. With this configuration, in the periphery of the sensor unit 2, the interface between the molded resin portion 22 of the sensor unit 2 and the sealing resin 4 is not exposed to the outside, and only the interface between the housing 3 and the sealing resin 4 is exposed to the outside.

[0093] The parallel step surfaces 326 are formed on the three remaining inner wall surfaces 323B other than the inner wall surface 323A on the conductive terminal side, the remaining inner wall surfaces 323B forming the case recess 32 to surround the side surface 222 of the molded resin portion 22 of the sensor unit 2. With this configuration, even if peeling occurs at the interface between the first vertical surface 325 of the remaining inner wall surface 323B of the housing 3 and the sealing resin 4 facing the first vertical surface 325, the parallel step surfaces 326 can prevent such peeling from being extended.

[0094] exist Figure 8 , the situation where peeling occurs at the interface between the first vertical surface 325 and the sealing resin 4 is shown by the alternating long and short dashed lines X. In this case, although the sealing resin 4 is separated from the first vertical surface 325 by peeling, the amount of the sealing resin 4 separated from the first vertical surface 325 becomes smaller as it moves toward the pressure receiving side L1. When the sealing resin 4 attempts to separate from the first vertical surface 325 in a direction parallel to the pressure receiving surface 210 of the pressure receiving portion 21 (i.e., a direction perpendicular to the axial direction L), the sealing resin 4 facing the parallel step surface 326 is in a state where it is difficult to separate from the parallel step surface 326. Therefore, even if peeling occurs between the first vertical surface 325 and the sealing resin 4, the extension of the peeling can be prevented by the parallel step surface 326.

[0095] Therefore, the pressure sensor 1 of the evaporated fuel leak detector according to the present embodiment can prevent the spread of peeling at the interface between the first vertical surface 325 and the sealing resin 4 , and can sufficiently improve the airtightness of the pressure sensor 1 .

[0096] Next, we will describe Fig.10 The inclined step surface 326X shown in FIG.

[0097] exist Fig.10 In the example shown, instead of Figure 8The parallel step surfaces 326 on each of the remaining inner wall surfaces 323B may form an inclined step surface 326X having an inner angle θ that is less than 90 degrees inclined relative to the pressure receiving surface 210. The inner angle θ is an angle between the first vertical surface 325 and the inclined step surface 326X. Since an acute inner angle θ is formed between the first vertical surface 325 and the inclined step surface 326X, peeling generated between the first vertical surface 325 and the sealing resin 4 can be prevented from advancing toward the pressure receiving side L1 as in the parallel step surfaces 326.

[0098] In each of the remaining inner wall surfaces 323B of the housing recess 32, the inclined surface 327 may not be formed between the first vertical surface 325 and the parallel step surface 326. For example, the first vertical surface 325, the parallel step surface 326, and the second vertical surface 328 may be formed in this order from the rear side L2 of the housing recess 32. Even in this case, the effect of preventing the extension of the peeling caused by the parallel step surface 326 can be obtained. In addition, an inclined step surface 326X may be used instead of the parallel step surface 326.

[0099] In addition, the parallel step surface 326 or the inclined step surface 326X may be formed in the inner wall surface 323A on the conductive terminal side. Therefore, even when peeling occurs at the interface between the inner wall surface 323A on the conductive terminal side and the sealing resin 4, extension of the peeling can be prevented by the parallel step surface 326 or the inclined step surface 326X. The parallel step surface 326 or the inclined step surface 326X may be formed only in a portion of the remaining inner wall surface 323B.

[0100] The other configuration, functions and effects of evaporated fuel processing device 1 of this embodiment are the same as those of the first embodiment. In this embodiment, components denoted by the same reference numerals as those in the first embodiment are the same as those in the first embodiment.

[0101] <Third Embodiment>

[0102] The pressure sensor 1 of the third embodiment is different from the pressure sensor of the first embodiment or the second embodiment, especially in the shape of the housing 3. Figures 11 to 13As shown, the pressure sensor 1 of the third embodiment also includes a sensor unit 2, a housing 3 and a sealing resin 4. Each remaining inner wall surface 323B of the housing recess 32 of the present embodiment is sequentially provided with a first vertical surface 325, an inclined surface 327 and a second vertical surface 328 in a cross section along the axial direction L perpendicular to the pressure receiving surface 210. The inclined surface 327 is inclined inwardly as it moves toward the pressure receiving side L1. The second vertical surface 328 extends from the end of the pressure receiving side L1 of the inclined surface 327 to define a filling gap 34 in which the sealing resin 4 is filled between the side surface 222 of the molded resin portion 22 and the second vertical surface 328. The inclined surface 327 and the second vertical surface 328 are formed on a plurality of remaining inner wall surfaces 323B that intersect each other.

[0103] The filling gap 34 may be formed to have a regular thickness within a distance in the axial direction L between the pressure receiving side L1 and the rear side L2 such that the thickness variation is within a range of, for example, 0.5 mm.

[0104] In this embodiment, if Fig.14 As shown in FIG. 1 , in a cross section along the axial direction L perpendicular to the pressure receiving surface 210, an end portion 327A of the inclined surface 327 on the pressure receiving side L1 is positioned at a rear side L2 of the outer edge portion 224 of the pressure receiving surface 210 of the molded resin portion 22 in parallel with the axial direction L. The difference between the positions of the end portion 327A and the outer edge portion 224 in the axial direction L is indicated by a reference symbol S. As a result, when the molded resin portion 22 of the sensor unit 2 is fitted into the fitting portion 321 of the housing recess 32, the molded resin portion 22 is fitted into the fitting portion 321 after being guided to the standard fitting position by the inclined surface 327.

[0105] The sealing resin 4 is filled up to the end 327B on the rear side L2 of the inclined surface 327 exceeding each remaining inner wall surface 323B on the rear side L2. In other words, the outer surface of the sealing resin 4 is located on the rear side L2 beyond the end 327B on the rear side L2 of the inclined surface 327. The entire inclined surface 327 of each remaining inner wall surface 323B is embedded in the sealing resin 4.

[0106] In addition, if Fig.11 and 12As shown, the sealing resin 4 covers the entire rear surface 223 of the molded resin portion 22 and the entire rear side portion 222B of the side surface 222 of the molded resin portion 22, except for the pressure receiving side portion 222A in the side surface 222 of the molded resin portion 22. By filling the sealing resin 4 to a position exceeding the inclined surface of the rear side L2, the thickness of the sealing resin 4 arranged on the rear side L2 of the molded resin portion 22 can be made equal to or greater than a specific thickness.

[0107] like Fig.14 As shown, in the cross section along the axial direction L perpendicular to the pressure receiving surface 210, the remaining inner wall surface 323B of the receiving recess 32 of the present embodiment is provided with a first vertical surface 325, an inclined surface 327, and a second vertical surface 328 in sequence from the rear side L2 of the receiving recess 32. The configuration of the first vertical surface 325, the inclined surface 327, and the second vertical surface 328 is similar to that of the second embodiment. However, a parallel step surface 326 or an inclined step surface 326X may be formed between the first vertical surface 325 and the inclined surface 327, as in Figures 8 to 10 In the example shown in .

[0108] (Functions and Effects)

[0109] In the pressure sensor 1 of the evaporated fuel leak detector of the present embodiment, the sealing resin 4 filled in the housing recess 32 covers the surface portion of the molded resin portion 22 arranged in the housing recess 32. That is, the sealing resin 4 completely covers the rear side portion 222B of the side surface 222 of the molded resin portion 22 and the rear surface 223 of the molded resin portion 22. With this configuration, it is difficult for electromagnetic noise or heat generated from the motor of the pressure-reducing pump 51 and the solenoid noise of the solenoid valve 52 arranged around the pressure sensor 1 of the pressure-reducing leak check module 10 to reach the sensor unit 2 from the rear side L2 of the sensor unit 2.

[0110] Each remaining inner wall surface 323B of the housing recess 32 of the present embodiment is provided with a first vertical surface 325, an inclined surface 327, and a second vertical surface 328 in sequence in a cross section along the axial direction L perpendicular to the pressure receiving surface 210. The inclined surface 327 is inclined inwardly as it approaches the pressure receiving side L1. The second vertical surface 328 extends from the end of the pressure receiving side L1 of the inclined surface 327 to define a filling gap 34 in which the sealing resin 4 is filled between the side surface 222 of the molded resin portion 22 and the second vertical surface 328. With this configuration, the thickness of the sealing resin 4 filled in the filling gap 34 between the side surface 222 of the molded resin portion 22 and the second vertical surface 328 is substantially uniform between the pressure receiving side L1 and the rear side L2 in the axial direction L.

[0111] exist Fig.14In the embodiment, due to the tapered shape of the rear portion 222B of the side surface 222 of the molded resin portion 22, the thickness of the sealing resin 4 filled in the filling gap 34 slightly changes in the axial direction L. However, in this case, due to the inclination angle of the inclined surface 327, the amount of change in the thickness of the sealing resin 4 filled in the filling gap 34 is smaller than the amount of change in the width of the sealing resin 4.

[0112] Due to the basically uniform thickness of the sealing resin 4 filled in the filling gap 34, when the pressure sensor 1 is heated or cooled, the thermal stress applied from the sealing resin 4 to the sensor unit 2 in a direction perpendicular to the axial direction L is basically uniform at each portion in the axial direction L.

[0113] In the present embodiment, the linear expansion coefficient of the sealing resin 4 is made larger than the linear expansion coefficient of the molded resin portion 22 of the sensor unit 2. When the pressure sensor 1 is heated, the amount of expansion of the sealing resin 4 becomes larger than the amount of expansion of the molded resin portion 22, so that thermal stress is applied from the sealing resin 4 filled in the filling gap 34 to the sensor unit 2 including the pressure receiving portion 21 and the molded resin portion 22. At this time, the thermal stress is proportional to the thickness of the sealing resin 4. However, in the present embodiment, by making the thickness of the sealing resin 4 filled in the filling gap 34 substantially uniform, the thermal stress acting on the sensor unit 2 from the sealing resin 4 can be made substantially uniform. In this way, since the thermal stress applied to the sensor unit 2 becomes substantially uniform, it is possible to prevent uneven deformation from being generated in the sensor unit 2.

[0114] Therefore, according to the pressure sensor 1 of the evaporated fuel leak detector of the present embodiment, the stress acting on the pressure receiving unit 21 due to the deformation of the sensor unit 2 can be reduced, and the pressure detection at the pressure receiving unit 21 can be accurately performed.

[0115] In addition, the inclined surface 327 and the vertical surface 328 may be formed at least on the two remaining inner wall surfaces 323B perpendicular to each other, so as to effectively guide the sensor unit 2 into the fitting portion 321 of the housing recess 32 using the inclined surface 327. If the two inclined surfaces 327 are provided in the remaining inner wall surfaces 323B perpendicular to each other, the position of the sensor unit 2 relative to the fitting portion 321 can be adjusted to be positioned in a plane parallel to the pressure receiving surface 210.

[0116] The other configurations, functions and effects of the pressure sensor 1 of this embodiment are similar to those of the first embodiment or the second embodiment. In the third embodiment above, the components indicated by the same reference numerals as those in the first embodiment or the second embodiment may have the same structure as those in the first embodiment or the second embodiment.

[0117] <Fourth Embodiment>

[0118] The pressure sensor 1 of the fourth embodiment is different from the pressure sensors of the first and third embodiments, especially in the shape of the housing 3. Figures 15 to 18 As shown, the pressure sensor 1 of the fourth embodiment also includes a sensor unit 2, a housing 3, and a sealing resin 4. A buffer recess 35 having an outer shape larger than the outer shape of the pressure receiving surface 210 is formed at the pressure receiving side L1 of the bottom of the housing recess 32 of the present embodiment. The buffer recess 35 is continuously formed at the pressure receiving side L1 of the housing recess 32, and is arranged on the pressure receiving side L1 instead of the sensor unit 2 in a state where the sensor unit 2 is assembled in the assembly portion 321 of the housing recess 32.

[0119] like Fig.15 , 16 As shown in FIGS. 1 and 18, a protruding cylindrical portion 36 is formed at the outer edge of the opening end of the fluid flow path 31 on the rear side L2 to protrude into the buffer recess 35 toward the rear side L2. The buffer recess 35 is formed in an annular shape around the protruding cylindrical portion 36. The housing recess 32 may be deeply formed to be more deeply recessed on the pressure receiving side L1 to have the buffer recess 35, thereby forming the protruding cylindrical portion 36 on the outer edge of the opening end of the fluid flow path 31 on the rear side L2. The protruding cylindrical portion 36 has a tubular shape, and the fluid flow path 31 is formed longer on the rear side L2 by the amount of the protruding cylindrical portion 36 formed.

[0120] like Fig.15 and Fig.18 As shown, a bottom surface 351 facing the molded resin portion 22 of the sensor unit 2 is formed at a bottom position of the pressure receiving side L1 of the housing recess 32 where the buffer recess 35 is not formed. The buffer recess 35 may be formed in various shapes around the protruding cylindrical portion 36.

[0121] like Fig.15 and 16 As shown in FIG. 1 , the pressure receiving surface 210 of the pressure receiving portion 21 of the sensor unit 2 is positioned on the rear side L2 from the end surface 221 of the pressure receiving side L1 of the molded resin portion 22. Then, the pressure receiving surface 210 of the pressure receiving portion 21 is in a state of being pulled toward the rear side L2 and recessed into the molded resin portion 22. In addition, the pressure receiving portion 21 is surrounded and protected by the molded resin portion 22.

[0122] A fluid passage gap 37 through which the fluid "R" passes is formed between the end portion of the rear side L2 of the protruding cylindrical portion 36 and the end surface 221 of the pressure receiving side L1 of the sensor unit 2. Due to the formation of the protruding cylindrical portion 36, the dimension (i.e., width) of the fluid passage gap 37 in the axial direction L is smaller than the depth from the end surface 221 of the pressure receiving side L1 of the molded resin portion 22 to the bottom surface of the pressure receiving side L1 of the buffer recess 35.

[0123] As in this embodiment Figures 15 to 17 As shown, an assembly gap 39 is provided between the periphery of the end portion of the pressure receiving side L1 of the molded resin portion 22 and the remaining inner wall surface 323B in three directions of the housing recess 32. The pressure receiving side portion 222A of the molded resin portion 22 is guided by the protruding portion 38 formed in the fitting portion 321 of the housing recess 32, and is fitted into the fitting portion 321 of the housing recess 32. The shape of the protruding portion 38 is easily changed by adjusting the shape of the molding die used to mold the housing 3. Therefore, the size of the assembly gap 39 can be easily adjusted.

[0124] (Functions and Effects)

[0125] In the pressure sensor 1 of the evaporated fuel leak detector of the present embodiment, the buffer recess 35 is formed at the pressure receiving side L1 of the bottom of the housing recess 32 and is positioned between the housing recess 32 and the fluid flow path 31. In addition, a protruding cylindrical portion 36 protruding into the buffer recess 35 toward the rear side L2 is formed at the outer edge of the opening end of the fluid flow path 31 on the rear side L2.

[0126] When the sealing resin 4 is filled in the housing recess 32 in which the sensor unit 2 is arranged, a part of the sealing resin 4 may flow from the housing recess 32 toward the fluid flow path 31 through the assembly gap 39. Even in this case, a part of the sealing resin 4 is blocked by the protruding cylindrical portion 36, and a part of the sealing resin 4 can be stored in the buffer recess 35. Therefore, a part of the sealing resin 4 can be prevented from flowing out to the fluid flow path 31.

[0127] If a portion of the sealing resin 4 flows into the fluid flow path 31, the air flow resistance of the fluid flow path 31 increases, and the responsiveness detected by the pressure sensor 1 may decrease. In addition, in this case, the orifice 541 may be blocked by a portion of the sealing resin 4. Therefore, the detection accuracy of the leakage check of the step-down leakage check module 10 may decrease.

[0128] In the present embodiment, since the sealing resin 4 can be stored in the buffer recess 35, the detection accuracy of the leakage check of the step-down leakage check module 10 can be effectively improved. The orifice 541 can be prevented from being blocked by the sealing resin 4 flowing from the receiving recess 32 toward the fluid flow path 31, and the sealing resin can be prevented from adhering to the pressure receiving surface 210 of the pressure receiving portion 21. As a result, the responsiveness of the pressure sensor 1 can be improved, and the detection error of the pressure sensor 1 can be effectively prevented. Therefore, the detection accuracy of the leakage check of the step-down leakage check module 10 can be improved. In addition, since the sealing resin 4 can be stored in the buffer recess 35, a certain amount of the sealing resin 4 can be allowed to flow out from the housing recess 32 to one side of the fluid flow path 31.

[0129] In the present embodiment, since the pressure receiving side portion 222A in the side surface 222 of the molded resin portion 22 is fitted into the housing recess 32, it is not necessary to use a concave-convex fitting structure between the molded resin portion 22 and the housing recess 32. Therefore, damage to the molded resin portion 22 can be effectively prevented.

[0130] Therefore, according to the pressure sensor 1 of the evaporated fuel leak detector of the present embodiment, the mold resin portion 22 of the sensor unit 2 can be protected, and the pressure can be accurately detected even when the sealing resin 4 flows out from the case recess 32 .

[0131] The other configurations, functions and effects of the pressure sensor 1 of this embodiment are similar to those of the first to third embodiments. In the fourth embodiment above, components indicated by the same reference numerals as those in the first to third embodiments may have the same structures as those in the first to third embodiments.

[0132] In the first to fourth embodiments, the pressure sensor 1 is applied to the depressurized leak check module 10. In addition, the pressure sensor 1 may be applied to a positive-pressure leak check module that performs a leak check in a pressurized state.

[0133] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. The modifications or changes made by those skilled in the art to these specific examples are also included in the scope of the present disclosure if appropriate, as long as they have the characteristics of the present disclosure. Each element included in the above-mentioned corresponding specific examples, and the arrangement, conditions, shape, etc. of these elements are not limited to those illustrated, and can be changed as appropriate. The corresponding elements included in the above-mentioned specific examples can be appropriately combined together, as long as there is no technical contradiction between them.

Claims

1. A pressure sensor for an evaporated fuel leak detector configured to detect leakage of evaporated fuel in an evaporated fuel processing device (6), the evaporated fuel processing device (6) comprising a fuel tank (61) and a canister (62) for adsorbing evaporated fuel discharged from the fuel tank, the pressure sensor comprising: A sensor unit (2) comprising a pressure receiving portion (21) configured to detect the pressure of a fluid applied to a pressure receiving surface (210), a plurality of conductive terminals (213) provided at the pressure receiving portion and made of a conductive material, and a molded resin portion (22) covering an outer surface of the pressure receiving portion except for the pressure receiving surface (210); a housing (3) provided with a fluid flow path (31) through which a fluid is introduced to the pressure receiving surface, and a housing recess (32) which accommodates the sensor unit therein and is connected to the fluid flow path; and A sealing resin (4) is filled in the housing recess accommodating the sensor unit to cover a surface of the molded resin portion arranged in the housing recess, wherein: The housing has an annular inner wall surface (323) defining the housing recess and surrounding the side surface (222) of the molded resin portion, and the annular inner wall surface of the housing includes a first inner wall surface (323A) on the conductive terminal side where a plurality of conductive terminals are arranged and a plurality of second inner wall surfaces (323B) intersecting with each other, and When the pressure receiving surface of the shell recess is arranged so that the direction exposed from the shell recess is the pressure receiving side (L1) and the direction opposite to the pressure receiving side of the shell recess is the rear side (L2), in a cross section along a direction perpendicular to the pressure receiving surface, the second inner wall surface has an inclined surface (327) inclined inwardly toward the pressure receiving side, and a vertical surface (328) adjacent to the pressure receiving side of the inclined surface, and the vertical surface (328) extends in a direction perpendicular to the pressure receiving surface to define a gap (34) filled with sealing resin between the side surface of the molded resin portion and the vertical surface.

2. The pressure sensor according to claim 1, wherein: In a cross section along a direction perpendicular to the pressure receiving surface, an end portion of the inclined surface on the pressure receiving side is positioned on the rear side beyond an outer edge portion (224) of the molded resin portion in a plane parallel to the pressure receiving surface, The side surface (222) of the molded resin portion has a pressure receiving side portion (222A) adjacent to the pressure receiving surface and a rear side portion (222B) excluding the pressure receiving side portion, The pressure receiving side portion of the side surface of the molded resin portion is fitted into the housing recess, and The sealing resin is filled in the case recess to a position beyond the rear side from the inclined surface to cover all the rear surface of the molded resin portion and the rear side portion (222B) of the molded resin portion except the pressure receiving side portion.

3. The pressure sensor according to claim 1 or 2, wherein: The inclined surface and the vertical surface are provided on at least two second inner wall surfaces that are perpendicular to each other.

Images