JP3702626B2 - Pressure sensor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pressure sensor.
[0002]
[Prior art]
Various pressure sensors have been conventionally provided. FIGS. 10 and 11 are a perspective view and a side sectional view showing an example of a conventional pressure sensor for detecting the pressure of a fluid such as gas or liquid. This pressure sensor A ′ has a sensor part 2 for converting the pressure of a fluid to be detected into an electric signal stored in the body 1 and a pressure introduction pipe 3 for introducing the fluid is provided in the body 1. . The sensor unit 2 includes a sensor chip in which a semiconductor substrate is processed to form a thin film diaphragm unit (not shown) and a detection element (such as a piezoresistor) that detects distortion due to pressure in the diaphragm unit. The container 1 is composed of a synthetic resin body 1a and a cover 1b, and a metal pressure introduction pipe 3 formed in a substantially cylindrical shape protrudes from the bottom of the substantially box-shaped body 1a by insert molding. I'm allowed. A plurality of terminals 4 are implanted in the body 1a in order to extract an electrical signal from the sensor unit 2 to the outside, and the distal ends of these terminals 4 are connected to the sensor unit 2 by wires 6 made of gold, aluminum, or the like. ing.
[0003]
On the other hand, the sensor unit 2 is attached to the end portion of the pressure introducing tube 3 by a glass pedestal 5, and the pressure of the pressure detection fluid such as gas or liquid introduced from the outside through the pressure introducing tube 3 is the above diaphragm. Applied to the part. The plurality of terminals 4 are projected in two directions from both side surfaces of the container body 1 so as to be easily mounted on a printed board.
[0004]
[Problems to be solved by the invention]
By the way, the pressure sensor A ′ as described above may be used to detect the oil pressure in the control of the automobile automatic transmission. However, the surge pressure is instantaneously increased during the pressure operation in which the oil pressure is repeatedly applied and released. If the surge pressure is larger than the breaking strength of the sensor unit 2, the sensor unit 2 is broken.
[0005]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a pressure sensor capable of preventing the sensor portion from being destroyed by the surge pressure of the pressure detection fluid.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is a pressure sensor in which a sensor part for converting pressure into an electrical signal is accommodated in the container, and a pressure introducing pipe for introducing a pressure detection fluid is provided in the container. in the communicating pipe Rutotomoni provided a filter for surge pressure relaxation to relieve surge pressure applied to the sensor unit by the fluid pressure introducing tube, is the pressure introduction pipe to the end portion is inserted, the pressure introduction pipe A deviation bush that has a deviation hole that deviates from the central axis of the pipe and that is fitted to the other end of the communication pipe and that has at least a distal end abutting against the filter . The sensor part can be prevented from being destroyed by the surge pressure of the fluid to be detected. In addition, the deviation bush can prevent the filter from coming off from the pressure introducing pipe and can fix the filter to obtain a stable surge pressure mitigating effect. Moreover, since the flow path from the deviation hole of the deviation bush to the pressure introduction pipe inserted into the communication pipe is bent, the surge pressure can be reduced even when the fluid particles collide with the wall and decelerate.
[0007]
According to a second aspect of the invention, in the invention of claim 1, the filter for the surge pressure relaxation, the metallic particles is characterized by that will be formed by sintering, of the pressure detection fluid when the surge pressure is generated Since the particles collide with the filter and the filter acts as a resistance and the fluid particles are decelerated, the surge pressure applied to the sensor unit is relaxed, and the sensor unit can be prevented from being destroyed.
[0008]
The invention according to claim 3, characterized in that in the invention of claim 1, the filter for the surge pressure relaxation, characterized by comprising knurling mesh is applied to the surface of the metal bar, the when the surge pressure is generated Since the particles of the pressure detection fluid collide with the filter and the filter acts as a resistance and the fluid particles are decelerated, the surge pressure applied to the sensor unit is relaxed, and the sensor unit can be prevented from being destroyed.
[0009]
The invention according to claim 4, characterized in that in the invention of claim 1, the filter for the surge pressure relaxation, characterized by comprising is formed with a plurality of longitudinal grooves in the surface of the metal bar, the when the surge pressure is generated Since the particles of the pressure detection fluid collide with the filter and the filter acts as a resistance and the fluid particles are decelerated, the surge pressure applied to the sensor unit is relaxed, and the sensor unit can be prevented from being destroyed.
[0010]
According to a fifth aspect of the present invention, in the first aspect of the invention, the surge pressure reducing filter is characterized in that a thread is formed on the surface of the metal rod, and the pressure detection is performed when a surge pressure is generated. Since the fluid particles collide with the filter and the filter acts as a resistance and the fluid particles are decelerated, the surge pressure applied to the sensor portion is alleviated and the sensor portion can be prevented from being destroyed.
[0011]
The invention of claim 6 is the invention of claim 1, the filter for the surge pressure relaxation, characterized by comprising a bar-shaped by compressing rounded metal net, when the surge pressure is generated Since the particles of the pressure detection fluid collide with the filter and the filter acts as a resistance and the fluid particles are decelerated, the surge pressure applied to the sensor unit is relaxed, and the sensor unit can be prevented from being destroyed. In addition, the filter particles are narrowed, so that the fluid particles can be more effectively decelerated and the degree of relaxation of the surge pressure can be adjusted according to the compression state.
[0012]
Invention 請 Motomeko 7, in any one of the claims 1 to 6, the insertion hole of the pressure introduction pipe to OsameSo the device body casing is inserted is provided on the case, the insertion hole The tip of the pressure introducing pipe is welded to the case over the entire circumference at the opening, and the pressure introducing pipe and the case are directly and airtightly fixed, so that a separate sealing material or the like Can be eliminated, and the structure can be simplified and the assemblability can be improved .
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Figure 1 is a side sectional view showing an embodiment of the present invention, a pressure inlet pipe 3 for introducing the accommodated and the fluid in Utsuwatai 1 a sensor unit 2 for converting the pressure of the pressure detection fluid into an electrical signal A pressure sensor element B provided in the body 1, a case 20 in which the pressure sensor element B is mounted, and a connector housing in which a terminal block (described later) is mounted and attached to the rear end of the case 20 30 and a pressure sensor A that detects the pressure of a fluid such as oil. Note that the basic configuration of the pressure sensor A (especially the pressure sensor element B) in this embodiment is almost the same as that of the conventional example, and therefore, common portions are denoted by the same reference numerals and description thereof is omitted. Only the part which becomes will be described.
[0014]
That is, in this embodiment, the metal filter 7 serving as a surge pressure reducing means for reducing an instantaneous surge pressure generated in a pressure detection fluid (hereinafter simply referred to as “fluid”) such as oil introduces pressure. It is characterized in that it is inserted into the tube 3.
As shown in FIG. 2, the filter 7 is formed into a substantially rod shape by sintering metal particles such as stainless steel and copper, and is inserted into the pressure introducing tube 3 of the pressure sensor element B. That is, the filter 7 is porous, and the fluid is introduced into the sensor portion 2 of the pressure sensor element B through the inside of the filter 7, but when a high surge pressure is momentarily generated, the fluid particles are filtered. When it passes through the inside of 7, it collides with the inner wall. As a result, since the filter 7 acts as a resistance and the fluid particles are decelerated, the surge pressure that passes through the filter 7 and reaches the sensor unit 2 is alleviated, and the sensor unit 2 is prevented from being destroyed by the surge pressure. Can do.
[0015]
By the way, the configuration of the filter 7 is not limited to that described above, and various configurations can be considered. For example, as shown in FIG. 3, the surface along the circumferential direction of the metal rod is knurled to form a large number of small irregularities, or as shown in FIG. 4, along the circumferential direction of the metal rod. The filter 7 may be formed with a plurality of longitudinal grooves 7a formed along the axial direction on the surface, or with a thread 7b formed along the circumferential direction on the surface of the metal rod as shown in FIG. . In these filters 7, the fluid collides with the knurls or the like when the fluid passes through the gap between the knurls (unevenness) or the vertical grooves 7 a or the threads 7 b formed on the surface of the metal rod and the inner wall of the pressure introducing pipe 3. It becomes a resistance and the surge pressure is relieved.
[0016]
Further, a metal net (hereinafter referred to as “metal mesh”) n as shown in FIG. 6 is rounded into a rod shape as shown in FIG. 7, and compressed into the pressure introducing pipe 3 as shown in FIG. Alternatively, the filter 7 may be configured by being inserted. Thus, in the filter 7, when the fluid passes through the inside of the filter 7, it collides with the metal mesh n and becomes a resistance, thereby reducing the surge pressure. In addition, according to the filter 7 made of the metal mesh n as described above, since the filter 7 becomes narrower, the fluid particles can be decelerated more effectively, and the degree of relaxation of the surge pressure can be reduced according to the compression state. There is an advantage that it is possible to adjust.
[0017]
On the other hand, the pressure sensor element B configured as described above is mounted on a ceramic circuit board 9 together with an electronic component 8 such as a signal amplification IC and is housed inside the case 20. A fixing screw 21 that holds the pressure introduction pipe 3 of the pressure sensor element B and fixes the pressure sensor element B to the case 20 is fitted to the tapered tip 20a of the case 20 so as to prevent rotation. An outer peripheral edge a (see FIG. 1) of the fixing screw 21 is fixed to the tip 20a of the case 20 by laser welding. The fixing screw 21 is provided with a through hole 21a along the axial direction, and an external fluid is guided into the pressure introducing pipe 3 through the through hole 21a. That is, in the present embodiment, the fixed screw 21 constitutes a communication pipe.
[0018]
The pressure introducing tube 3 is inserted from the inside of the case 20 into the insertion hole 20 b of the distal end portion 20 a, and an O-ring 22 is formed in the gap between the opening peripheral edge of the insertion hole 20 b and the base portion of the pressure introducing tube 3. Is interposed and sealed. A peripheral wall 20c projects from the rear end of the case 20, and a connector housing 30 in which the terminal block 31 is housed is fitted inside the peripheral wall 20c.
[0019]
The connector housing 30 has a substantially bottomed cylindrical base portion 30a and a connector portion 30b protruding from the rear end side of the base portion 30a. A terminal block 31 is accommodated in the base portion 30a. The terminal block 31 has a structure in which three connector pins 32 are press-fitted into a fixing portion 31a made of a synthetic resin molded product, and the fixing portion 31a and the connector pin 32 are fixed with an adhesive 33 and sealed at the press-fitting location. Have. Each connector pin 32 protruding from the fixed portion 31a of the terminal block 31 is inserted into a through hole 30c provided in the bottom portion of the connector portion 30b and protrudes inside the connector portion 30b. Here, a seal rubber 35 is fitted around the fixed portion 31a at the bottom of the base portion 30a, and the seal performance between the connector portion 30b and the terminal block 31 can be improved by the seal rubber 35.
[0020]
A shield plate 36 is attached to the opening end of the base portion 30a, and the base end portion of each connector pin 32 protruding from the fixing portion 31a toward the shield plate 36 penetrates the printed board 37 made of glass epoxy resin. It penetrates through the hole 37a and is soldered.
On the other hand, a plurality of connection pins 10 project from the opposite mounting surface of the circuit board 9 accommodated in the case 20, and these connection pins 10 pass through the shield plate 36 through the printed circuit board 37. The connector pin 32 is electrically connected.
[0021]
Then, the base portion 30 a of the connector housing 30 is fitted inside the peripheral wall 20 c at the rear end of the case 20, and the connector housing 30 is fitted to the case 20 by caulking the end edge portion of the peripheral wall 20 c. Further, a groove 23 is provided on the outer peripheral surface of the base portion 30a that is in contact with the peripheral wall 20c of the case 20 over substantially the entire circumference, and a sealing O-ring 24 is accommodated in the groove 23. Therefore, the gap between the case 20 and the connector housing 30 is sealed by the O-ring 24 housed in the groove 23.
[0022]
By the way, a deviation bush 40 made of metal (for example, SS41) is fitted into the through hole 21a of the fixing screw (communication pipe) 21 fixed to the tip portion 20a of the case 20 from the opening end side. As shown in FIG. 9, the deviation bush 40 includes a columnar main portion 40a and a contact portion 40b protruding from one end surface of the main portion 40a and having a diameter smaller than that of the main portion 40a. A pair of deviation holes 40c that deviate from the central axis of the pressure introducing pipe 3 are formed in the peripheral surface of the portion 40a.
[0023]
Thus, as shown in FIG. 1, when the deviation bush 40 is fitted into the through hole 21 a of the fixing screw 21 from the opening end side, the tip of the abutting portion 40 b comes into contact with the filter 7. Therefore, the filter 7 can be prevented from coming off from the pressure introducing pipe 3, and the filter 7 can be fixed to obtain a stable surge pressure mitigating effect. Further, the fixing screw 21 is inserted to the inside of the insertion hole 20b, and the end portion on the opening end side of the fixing screw 21 to which the deviation bush 40 is fitted is formed to be slightly wider, thereby opening the insertion hole 20b. The flow path from the end to the sensor portion 2 of the pressure sensor element B through the deviation hole 40c of the deviation bush 40 and the through hole 21a of the fixing screw 21 is bent. That is, since the fluid particles introduced through the deviation hole 40c of the deviation bush 40 collide with the opening end portion of the fixing screw 21 and the step portion 21b of the inner wall and are decelerated, this can also reduce the surge pressure. Is .
[0024]
【The invention's effect】
The invention according to claim 1 is a pressure sensor in which a sensor part for converting pressure into an electrical signal is housed in the body, and a pressure introduction pipe for introducing a pressure detection fluid is provided in the body. Rutotomoni provided a filter for surge pressure relaxation to relieve surge pressure applied to the pressure introducing tube, and a communicating pipe the pressure introducing tube is inserted into one end, a deviation hole deviation from the central axis of the pressure introduction pipe And a deviation bush that is fitted to the other end of the communication pipe and at least the tip of the communication pipe abuts against the filter . destruction can be prevented, also, this to obtain the relaxation effect of that filter is fixed stable surge pressure with attained the retaining filter from the pressure inlet pipe deviation bushing Moreover, since the flow path from the deviation hole of the deviation bush to the pressure introduction pipe inserted into the communication pipe is bent, the surge pressure can be reduced even if the fluid particles collide with the wall and decelerate. there is an effect that is Ru can.
[0025]
A second aspect of the present invention, filters for the surge pressure relaxation, since the metal particles Ru is formed by sintering, particles of the pressure detection fluid impinges on the filter when a surge pressure occurs, the filter resistance Since the fluid particles are decelerated, the surge pressure applied to the sensor unit is relaxed, and the sensor unit can be prevented from being destroyed.
[0026]
A third aspect of the present invention, filters for the surge pressure relaxation, so formed by knurling mesh is applied to the surface of the metal bar, particles of the pressure detection fluid impinges on the filter when a surge pressure occurs Since the fluid particles are decelerated by the resistance of the filter, the surge pressure applied to the sensor unit is relaxed, and the sensor unit can be prevented from being destroyed.
[0027]
A fourth aspect of the present invention, filters for the surge pressure relaxation, since a plurality of longitudinal grooves in the surface of the metal bar formed by forming the particles of the pressure detection fluid impinges on the filter when a surge pressure occurs Since the fluid particles are decelerated by the resistance of the filter, the surge pressure applied to the sensor unit is relaxed, and the sensor unit can be prevented from being destroyed.
[0028]
The invention of claim 5, the filter for the surge pressure relaxation, since threaded surface of the metal bar is formed by forming the particles of the pressure detection fluid impinges on the filter when a surge pressure is generated, the filter Since the fluid particles are decelerated due to the resistance, the surge pressure applied to the sensor unit is relaxed, and the sensor unit can be prevented from being destroyed.
[0029]
The invention of claim 6, the filter for the surge pressure relaxation, so compresses rounded metal net formed by a rod shape, the particles of the pressure detection fluid is a clash filter when a surge pressure occurs In addition, since the fluid particles are decelerated due to the resistance of the filter, the surge pressure applied to the sensor unit can be relaxed to prevent the sensor unit from being destroyed, and the filter particles are narrowed. It is possible to decelerate more effectively and to adjust the degree of relaxation of surge pressure according to the compression state.
[0030]
Invention 請 Motomeko 7, an insertion hole of the pressure introduction pipe to OsameSo the device body casing is inserted is provided on the case, the leading end of the pressure introduction pipe in the openings of the insertion hole Since it is welded to the case over almost the entire circumference, the pressure introducing tube and the case are directly and airtightly fixed, so no additional sealing material is required, and the structure can be simplified and the assembly can be improved. There is an effect .
[Brief description of the drawings]
FIG. 1 is a side sectional view showing an embodiment.
FIG. 2 is a perspective view of the filter in the same as above.
FIG. 3 is a perspective view of another filter in the same as above.
FIG. 4 is a perspective view of still another filter in the same as above.
FIG. 5 is a perspective view of still another filter according to the above.
FIG. 6 is a perspective view of a metal mesh constituting another filter in the same as above.
FIG. 7 is a perspective view showing a state in which the metal mesh is rolled up.
FIG. 8 is a cross-sectional side view of a main part showing a state in which the metal mesh is pressed into a pressure introducing pipe.
FIGS. 9A and 9B show the deviation bush, wherein FIG. 9A is a side view and FIG. 9B is a bottom view.
FIG. 10 is a perspective view showing a conventional example.
FIG. 11 is a side sectional view of the above.
[Explanation of symbols]
A Pressure sensor B Pressure sensor element 1 Body 2 Sensor part 3 Pressure introduction pipe 7 Filter 20 Case 30 Connector housing 40 Deviation bush

Claims (7)

A pressure sensor that houses a sensor part that converts pressure into an electrical signal and that has a pressure introduction pipe that introduces a fluid to be detected is provided in the body, reducing the surge pressure applied to the sensor part by the fluid. Rutotomoni provided a filter for surge pressure relaxation of the pressure introducing tube, and a communicating pipe the pressure introducing tube is inserted into one end, it has a deviation hole deviation from the central axis of the pressure inlet pipe of the communicating pipe A pressure sensor, comprising: a deviation bush that is fitted to the other end and has at least a tip abutting against the filter . Filters for the surge pressure relieving a pressure sensor according to claim 1, wherein the metal particles Ru is formed by sintering. Filters for the surge pressure relieving a pressure sensor according to claim 1, characterized by comprising been decorated with knurling mesh on the surface of the metal bar. Filters for the surge pressure relieving a pressure sensor according to claim 1, wherein the composed is formed with a plurality of longitudinal grooves in the surface of the metal bar. Filters for the surge pressure relieving a pressure sensor according to claim 1, wherein the composed is formed threads on the surface of the metal bar. Filters for the surge pressure relieving a pressure sensor according to claim 1, wherein the formed by a rod shape by compressing rounded metal net. The case is installed in the case, and an insertion hole into which the pressure introduction tube is inserted is provided in the case, and the tip portion of the pressure introduction tube is provided over the entire circumference at the opening of the insertion hole. The pressure sensor according to claim 1, wherein the pressure sensor is welded to the pressure sensor .

Images