JP2007278788A - Pressure detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent increase in pressure in a pressure-receiving chamber in the assembled state, in a pressure detecting device wherein a medium is filled into the pressure-receiving chamber, facing one surface of a diaphragm and a semiconductor pressure-sensitive element, having a support member that has a through hole, a semiconductor pressure sensor formed by including the semiconductor pressure-sensitive element into a housing, having a pressure introduction pipe inserted fluid-tightly into the through hole, and the diaphragm covering the other end side of the through hole, whose edge part is supported by the support member. <P>SOLUTION: A step part 10b facing outward is formed on one end of the through hole 10; and a large-diameter hole part 10a is provided; and a ring-shaped elastic seal member 11, having an inside diameter larger than the outside diameter of the pressure inlet pipe 5a in the natural state is inserted into the large-diameter hole part 10a, and in a state where the pressure inlet pipe 5a is inserted into the through hole 10, the elastic seal member 11 is pinched in between the pressure introduction pipe 5a and the step part 10b, and a seal pinching member 25, for bringing the inner circumference of the elastic seal member 11 close to the outer circumference of the pressure inlet pipe 5a over the whole circumference, is mounted on the support member 9. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention provides a semiconductor pressure sensor in which a semiconductor pressure-sensitive element is built in a housing having a support member having a through-hole, a pressure introduction pipe fitted fluid-tightly into the through-hole from one end thereof, and the through-hole A diaphragm that covers the other end of the hole and has a peripheral edge supported by the support member, and a pressure receiving pressure formed between the support member, the housing, and the diaphragm so as to face one surface of the diaphragm and the semiconductor pressure-sensitive element The present invention relates to a pressure detection device in which a chamber is filled with a medium.

Such a pressure detection device is already known from, for example, Patent Document 1, in which a pressure introduction tube is provided on the inner periphery of the elastic seal member in a state where the elastic seal member is attached to one end of the through hole. The pressure introducing tube is fitted into the through hole while the outer periphery is in sliding contact.
JP 2003-50172 A

  However, in the above-mentioned conventional one, since the inner periphery of the elastic seal member is in sliding contact with the outer periphery of the pressure introduction tube when the pressure introduction tube is assembled to the support member, the volume of the pressure receiving chamber in a liquid-tightly sealed state is reduced. The pressure introducing pipe is fitted into the support member in such a manner that the pressure is reduced, and the pressure in the pressure receiving chamber increases in the assembled state of the pressure introducing pipe, and the lower limit value of the detectable pressure is limited.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a pressure detection device that prevents the pressure in the pressure receiving chamber from increasing in the assembled state.

  To achieve the above object, according to the present invention, a semiconductor pressure sensitive element is incorporated in a housing having a support member having a through hole and a pressure introducing pipe fitted fluid-tightly into the through hole from one end side thereof. A semiconductor pressure sensor comprising: a diaphragm that covers the other end of the through-hole and has a peripheral edge supported by the support member; one surface of the diaphragm and the semiconductor pressure-sensitive element facing the support member, the housing, and In the pressure detection device in which a pressure receiving chamber formed between the diaphragms is filled with a medium, a large-diameter hole portion is formed at one end of the through hole by forming a stepped portion facing outward. An annular elastic seal member having an inner diameter larger than the outer diameter of the pressure introduction pipe and a part protruding outward from the support member is inserted into the large diameter hole, and the pressure introduction pipe is fitted into the through hole. A seal pinching member is attached to the support member so that the elastic seal member is pinched between the stepped portion and the inner periphery of the elastic seal member is in close contact with the outer periphery of the pressure introduction pipe over the entire circumference. It is characterized by being able to.

  In addition, the nut 25 of an Example respond | corresponds to the seal clamping member of this invention.

  According to the above configuration of the present invention, when the pressure introducing tube is fitted into the through hole, the elastic seal member inserted in the large diameter hole at one end of the through hole is in contact with the outer periphery of the pressure introducing tube. There is no seal between the pressure introducing tube and the support member. Therefore, even if the volume of the pressure receiving chamber decreases due to the insertion of the pressure introducing pipe, the pressure in the pressure receiving chamber does not increase. After the fitting of the pressure introducing pipe is completed, the seal clamping member is attached to the support member to Since the periphery of the pressure introducing tube is in close contact with the outer periphery of the pressure introducing tube, the sealing performance of the pressure receiving chamber is maintained, so that the pressure in the pressure receiving chamber can be prevented from increasing in the assembled state.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

  1 and FIG. 2 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of the pressure detecting device, and FIG. 2 is a longitudinal sectional view of a main portion of the pressure detecting device sequentially showing an assembling process.

  First, in FIG. 1, this pressure detection device is for detecting the pressure of a pressure medium having corrosiveness with respect to a semiconductor pressure-sensitive element 2 provided in the semiconductor pressure sensor 1 using the semiconductor pressure sensor 1. It is connected to a pipe line 3 through which a pressure medium flows through a T-shaped joint 4.

  The semiconductor pressure sensor 1 has a pressure introduction pipe 5a and a semiconductor pressure sensitive element 2 built in a housing 5 formed of a synthetic resin. A piezoresistor is formed on the surface of a diaphragm made of a thin silicone wafer. The formed semiconductor pressure-sensitive element 2 is bonded to the inner surface of the housing 5 so as to face the proximal end opening of the pressure introducing tube 5a. Further, a plurality of terminals 6, 6. Moreover, the outer ends of the respective terminals 6, 6... Are connected to a sensor module 7, which is a separate body from the housing 5, and the sensor module 7 is arranged at a position sandwiching the sensor module 7 with the semiconductor pressure sensor 1. The substrate 8 is supported.

  The semiconductor pressure sensor 1 is attached to one side of the support member 9. This support member 9 is integrally formed with a disk portion 9a and a cylindrical portion 9b that protrudes coaxially from the central portion of one side of the disk portion 9a, and is formed of a metal such as brass, for example. A through hole 10 is provided at the center of the member 9.

  A large-diameter hole portion 10a having one end opened to the outside is coaxially provided at one end portion of the through hole 10 so as to form an annular step portion 10b facing outward. An annular elastic seal member 11 is interposed between the pressure introduction pipe 5a included in the inner diameter 5 and the inner surface of the large-diameter hole 10a. The pressure introduction pipe 5a is fluid-tightly fitted into the through-hole 10 from one end thereof. Will be.

  On the other side of the support member 9, a peripheral portion of a diaphragm 12 made of metal, for example, stainless steel, covering the other end of the through hole 10 is supported. A pressure receiving chamber 13 is formed between the support member 9, the housing 5 and the diaphragm 12 so as to face one surface of the diaphragm 12 and the semiconductor pressure sensitive element 2, and at least a part of the pressure receiving chamber 13 is compressible. In this embodiment, the whole amount of the medium is air.

  On the outer peripheral portion of the disk portion 9a in the support member 9, the entire outer peripheral portion of the holding member 14 formed in a dish shape with metal, for example, stainless steel, holds the peripheral portion of the diaphragm 12 between the disk portion 9a. In this way, they are caulked and combined. Thus, ring-shaped seal members 15 and 16 are sandwiched between the outer peripheral surface of the diaphragm 12 and the disk portion 9a and the clamping member 14. A connecting tube portion 14a that protrudes on the opposite side of the diaphragm 12 is integrally formed at the center of the clamping member 14, and the joint 4 is connected to the connecting tube portion 14a by screwing or the like.

  By the way, a surface 17 facing one surface of the diaphragm 12 in the disk portion 9a of the support member 9 is formed in a tapered shape having a smaller diameter as the distance from the diaphragm 12 increases. The other end of the through hole 10 is formed at the center of the surface 17. However, when the pressure acting on the other surface of the diaphragm 12 exceeds a predetermined value, the central portion of one surface of the diaphragm 12 is brought into contact with the peripheral edge at the other end of the through hole 10. The small-diameter throttle hole 10d formed so as to have a smaller diameter than the outer diameter of the pressure introducing pipe 5a is formed with an annular receiving step portion 10c facing the opposite side of the diaphragm 12 near the other end of the through-hole 10. To be provided.

  A male screw 24 is engraved on the outer periphery of the cylindrical portion 9 b of the support member 9, and a nut 25, which is a seal clamping member, is in contact with the support plate 19 at the periphery of the insertion hole 18. Screwed together. One end of the nut 25 is integrally provided with a pinching collar portion 25a that projects inward in the radial direction.

  The cylindrical portion 9 b, the nut 25, the semiconductor pressure sensor 1, the sensor module 7, and the substrate 8 in the support member 9 are covered with a bottomed cylindrical cover 22 that makes the opening end abut on the disk portion 9 a of the support member 9. . Screw members 21 are screwed into a plurality of locations in the circumferential direction of the cover 22, and an annular groove 20 is provided on the outer periphery of the nut 25 to abut and engage the tips of the screw members 21.

  Incidentally, the elastic seal member 11 interposed between the pressure introduction pipe 5a of the housing 5 and the support member 9 has an inner diameter larger than the outer diameter of the pressure introduction pipe 5a in a natural state. In the state where the nut 25 is loosened, the elastic seal member 11 is inserted into the large-diameter hole portion 10a of the through hole 10 so that a part of the elastic seal member 11 protrudes from the cylindrical portion 9b. In this state, even if the pressure introducing tube 5a is fitted into the through hole 10 until it abuts against the stepped portion 10c, the inner periphery of the elastic seal member 11 does not contact the outer periphery of the pressure introducing tube 5a.

  Thus, as shown in FIG. 2B, when the nut 25 is tightened with the pressure introduction pipe 5 a being fitted into the through hole 10, the pinching flange 25 a included in the nut 25 is removed from the support member 9. When the nut 25 is further tightened by coming into contact with the protruding portion of the elastic seal member 11, the elastic seal member 11 is pinched between the pinching collar portion 25 a and the step portion 10 b, and the inner periphery of the elastic seal member 11 is the pressure introduction pipe. The outer periphery of the elastic seal member 11 is in close contact with the inner periphery of the large-diameter hole 10a over the entire periphery.

  Next, the operation of this embodiment will be described. At the end of the through-hole 10 provided in the support member 9 on the diaphragm 12 side, one surface of the diaphragm 12 according to the pressure acting on the diaphragm 12 exceeds a predetermined value. A small-diameter throttle hole 10d that abuts the central portion against the peripheral portion is provided with a smaller diameter than the outer diameter of the pressure introducing tube 5a, and faces the one surface of the diaphragm 12 and the semiconductor pressure-sensitive element 2 to support the member 9, The pressure receiving chamber 13 formed between the housing 5 and the diaphragm 12 is filled with a medium (a medium in which the entire amount is air in this embodiment) having at least a part as a compressive fluid.

  In other words, the inner diameter of the other end of the through hole 10 is made relatively small by providing a small-diameter throttle hole 10d that is smaller than the outer diameter of the pressure introducing tube 5a, and the diaphragm 12 is excessively larger than the set pressure. Even if the pressure further increases after the central portion of one surface of the diaphragm 12 comes into contact with the peripheral edge of the other end of the through hole 10 due to the pressure, the deformation amount of the diaphragm 12 in the other end of the through hole 10 is relatively small. Can be kept small. In addition, since at least a part of the medium filled in the pressure receiving chamber 13 is a compressive fluid, a pressure increase corresponding to the volume reduction corresponding to the deformation of the diaphragm 12 in the other end of the through hole 10 occurs in the pressure receiving chamber 13. Only.

  In this way, it is possible to prevent an excessive force from acting on the semiconductor pressure sensitive element 2 facing the pressure receiving chamber 13, and a failure of the semiconductor pressure sensitive element 2 occurs even if an excessive pressure action is applied to the diaphragm 12. This can be prevented.

  Moreover, a stepped portion 10b facing outward is formed at one end of the through-hole 10, and a large-diameter hole portion 10a is provided. In a natural state, the inner diameter is larger than the outer diameter of the pressure introducing tube 5a and a part thereof is supported. An annular elastic seal member 11 that protrudes outward from the member 9 is inserted into the large-diameter hole portion 10a, and the elastic seal member 11 is placed between the step portion 10b and the pressure introduction pipe 5a inserted in the through-hole 10. A nut 25 is attached to the support member 9 so that the inner periphery of the elastic seal member 11 is in close contact with the outer periphery of the pressure introducing tube 5a over the entire periphery.

  That is, when the pressure introduction pipe 5a is fitted into the through hole 10 with the nut 25 loosened, the elastic seal member 11 inserted into the large diameter hole 10a does not contact the outer periphery of the pressure introduction pipe 5a. In addition, the space between the pressure introducing pipe 5a and the support member 9 is not sealed. Therefore, even if the volume of the pressure receiving chamber 13 decreases due to the insertion of the pressure introducing pipe 5a, the pressure in the pressure receiving chamber 13 does not increase. After the fitting of the pressure introducing pipe 5a is completed, the nut 25 is attached to the support member 9 to provide an elastic seal. Since the sealing performance of the pressure receiving chamber 13 is maintained when the inner periphery of the member 11 is in close contact with the outer periphery of the pressure introducing pipe 5a, the pressure of the pressure receiving chamber 13 increases in the assembled state. Can be prevented.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.

It is a longitudinal cross-sectional view of a pressure detection apparatus. It is a principal part longitudinal cross-sectional view of the pressure detection apparatus which shows an assembly | attachment process sequentially.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Semiconductor pressure sensor 2 ... Semiconductor pressure sensitive element 5 ... Housing 5a ... Pressure introduction pipe 9 ... Support member 10 ... Through-hole 10a ... Large diameter hole part 10b ... Step 11 ... Elastic seal member 12 ... Diaphragm 13 ... Pressure receiving chamber 25 ... Nut which is a seal clamping member

Claims (1)

  A semiconductor pressure sensitive element (9) in a housing (5) having a support member (9) having a through hole (10) and a pressure introducing pipe (5a) fitted into the through hole (10) from one end thereof in a fluid-tight manner. 2) a semiconductor pressure sensor (1) having a built-in structure, a diaphragm (12) covering the other end of the through hole (10) and having a peripheral edge supported by the support member (9), and the diaphragm ( 12) and a pressure receiving chamber (13) formed between the support member (9), the housing (5), and the diaphragm (12) with the semiconductor pressure-sensitive element (2) facing each other, are filled with a medium. In the pressure detecting device, a step portion (10b) facing outward is formed at one end of the through hole (10) to provide a large diameter hole portion (10a). ) Has an inner diameter larger than the outer diameter An annular elastic seal member (11) that partially protrudes outward from the support member (9) is inserted into the large-diameter hole (10a), and the pressure introducing pipe (5a) is inserted into the through-hole (10). The elastic seal member (11) is clamped between the stepped portion (10b) in the inserted state, and the inner periphery of the elastic seal member (11) is extended to the outer periphery of the pressure introducing pipe (5a). A pressure detecting device, wherein a sealing pinching member (25) to be in close contact is attached to the support member (9).

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