JP6362497B2 - Pressure sensor - Google Patents

Description

  The present invention relates to a pressure sensor, and more particularly to a pressure sensor in which a liquid is sealed in a pressure receiving space in which a pressure detection element is accommodated.

  Conventionally, liquid (oil) is sealed in a pressure detection chamber (pressure receiving space) in which a semiconductor pressure detection element is accommodated, and the pressure of a refrigerant or the like applied from the outside to the pressure detection chamber is transferred to the semiconductor pressure via the liquid. Various pressure sensors that output a voltage signal corresponding to pressure from the pressure detection element by transmitting the detection element to the detection element have been proposed.

  As such a pressure sensor, for example, a diaphragm, a pressure receiving space in which oil is sealed between the diaphragm and a base in which a semiconductor pressure detecting element is provided in the pressure receiving space, and the diaphragm A flow pipe connecting member provided opposite to the base and connected to a fluid inflow pipe and having a pressure introduction space between the diaphragm and pressure introduced through the fluid inflow pipe; A pressure sensor that is drawn out from the back of the base and includes a lead pin connected to the bonding pad (terminal) of the semiconductor pressure detection element via a bonding wire and a lead wire connected to the lead pin, and the pressure detection unit is accommodated And a resin cover that is formed by dividing the inside of the cover by the pressure detection unit. Resin (adhesive) is sealed in the first space that accommodates the lead pin and the lead wire, and the second space formed between the flow tube connecting member side of the pressure detection unit and the cover, and the lead pin Is known that is attached and sealed to the base by a hermetic seal using glass (see Patent Document 1).

JP 2012-68105 A

The pressure sensor has a structure in which a through hole is provided in a base made of stainless steel or the like, a lead pin is passed through this, and sealed with a hermetic seal made of glass.
Since the base does not melt at the time of sealing, the glass of the hermetic seal part and the metal of the base are not integrated. For this reason, a high pressure is applied in the pressure receiving space, and this is repeated, or the pressure sensor is alternately exposed to both a high temperature atmosphere and a low temperature atmosphere due to a change in the outside air temperature or the like. When a strong impact is applied to the pressure sensor, there is a concern that the hermetic seal part will crack, or that there will be a gap at the interface between the hermetic seal part and the base, and in some cases the hermetic seal part will come off the base. It was.
When the hermetic seal part is damaged, the oil sealed in the pressure receiving space leaks from the damaged part, and as a result, the pressure of the fluid such as a refrigerant to be detected when the pressure sensor is operated is directly applied to the diaphragm without passing through the oil. In addition, the diaphragm may be damaged. In this case, a liquid such as a refrigerant whose pressure is to be detected leaks to the outside through the pressure sensor.

  Therefore, an object of the present invention is to provide a pressure sensor that can suppress the damage of the diaphragm even when oil leakage from the hermetic seal portion occurs.

In order to solve the above problems, a pressure sensor according to the present invention includes a diaphragm, a base in which a pressure receiving space in which oil is sealed is formed between the diaphragm, and a pressure detection element provided in the pressure receiving space; A receiving member provided opposite to the base with a diaphragm interposed therebetween and connected to a fluid inflow pipe, and a pressurizing space in which pressure is introduced through the fluid inflow pipe between the diaphragm and the diaphragm; A pressure detection part integrally joined, and a lead pin connected to the pressure detection part is sealed by a hermetic seal part with respect to a through-hole provided in the base, and pressure received between the diaphragm and the base in the space, the deformation being deformation suppressing member further arrangement with suppressing the contact surface of the diaphragm, the base, the top wall and the peripheral of the top wall And a upright flange portion, the deformation suppressing member has its outer peripheral portion is in contact freely inside surface sliding of the collar portion.
The deformation suppressing member may have at least one through hole, groove, or mesh portion.

In an embodiment of a pressure sensor according to the present invention, the deformation suppressing member, Ru is configured so that its outer periphery is joined pinched between said receiving member and said base.

In still another embodiment of the pressure sensor according to the present invention, the deformation suppressing member is configured such that an outer peripheral portion thereof is directly joined to an inner surface of the base.
At this time, the said deformation | transformation suppression member may be comprised by the plate-shaped part which comprises the said contact surface, and the leg part arrange | positioned on the outer periphery of the said plate-shaped part.
In this case, a recess may be provided in the leg portion, and the recess may be configured to face the hermetic seal portion.

The pressure sensor according to the present invention can prevent the diaphragm from being damaged even if oil leakage from the hermetic seal portion occurs by providing the deformation detecting member in the pressure detecting portion.
Moreover, a pressure detection part can be manufactured with a simple process by selecting suitably the shape and structure of the said deformation | transformation suppression member.

It is a longitudinal section showing an outline of pressure sensor 100 of the 1st example of the present invention. It is a top view which shows the outline | summary of the deformation | transformation suppression member 5 applied to the 1st Example of this invention. FIGS. 3A and 3B are diagrams showing a pressure detection unit 210 and components in the vicinity thereof in a second embodiment of the present invention, FIG. 3A is a longitudinal sectional view of the pressure detection unit 210, and FIG. Is a sectional view taken along line XX. It is a figure which shows the outline | summary of the deformation | transformation suppression member 50 applied to the 2nd Example of this invention, FIG. 4 (A) is a top view of the deformation | transformation suppression member 50, FIG.4 (B) is FIG. It is sectional drawing in a YY line. It is a longitudinal cross-sectional view of the pressure detection part 310 in the 3rd Example of this invention, and the component of the vicinity. It is a longitudinal cross-sectional view of the pressure detection part 10 in the 4th Example of this invention, and the component of the vicinity. It is a top view which shows the modification of the deformation | transformation suppression member 5 applied to the pressure sensor 100 of 1st Example of this invention.

FIG. 1 is a longitudinal sectional view showing a first embodiment of a pressure sensor according to the present invention.
As shown in FIG. 1, the pressure sensor 100 includes a pressure detection unit 110 provided with a pressure detection element 41 therein and connected to the fluid inflow pipe 11, and covers the pressure detection unit 110 and is connected to the pressure detection element 41. The connector connection part 120 which accommodated the board | substrate 45 and the lead wire 47 was provided.

The pressure detection unit 110 includes a base 1, a receiving member 2 disposed so as to face the base 1, a diaphragm 3 sandwiched between the base 1 and the receiving member 2, and between the base 1 and the diaphragm 3. And a deformation suppressing member 5 sandwiched between the two.
The receiving member 2 plays a role as a flow tube connecting member to which the fluid inflow tube 11 is connected at the center. A pressure receiving space 31 in which oil is enclosed is formed between the base 1 and the diaphragm 3. As shown in FIG. 1, the deformation suppressing member 5 is provided in the pressure receiving space 31 so as to face the diaphragm 3. In this state, the diaphragm 3 and the deformation suppressing member 5 are sandwiched and attached to the base 1 and the receiving member 2.
On the other hand, a pressurizing space 12 as a pressure introducing space is formed between the receiving member 2 and the diaphragm 3, and a fluid inflow pipe 11 communicates with the pressurizing space 12. A fluid (such as a refrigerant in a refrigeration cycle) whose pressure is to be detected is introduced into the pressurized space 12 through the fluid inflow pipe 11. Here, the base 1, the receiving member 2, the diaphragm 3, and the deformation suppressing member 5 are preferably made of metal such as stainless steel. Moreover, since the diaphragm 3 has a function of propagating the fluid pressure to be detected on the pressurized space 12 side to the pressure receiving space 31 side, the diaphragm 3 is desirably thin.

The base 1 is formed in a lid shape having a flange 1a at the periphery, and the pressure detection element 41 is attached to the inner surface of the top wall 1b of the lid. The receiving member 2 is formed in the shape of a dish whose periphery rises and is a flat flange 2a. An opening 2b is formed at the center of the receiving member 2, and the fluid inflow pipe 11 is brazed and fixed to the opening 2b.
The diaphragm 3 and the deformation suppressing member 5 sandwiched between the base 1 and the receiving member 2 are sandwiched between the flange portion 1 a of the base 1 and the flange portion 2 a of the receiving member 2. . These four members are circumferentially welded simultaneously by a welded portion 4 such as laser welding at their outer peripheral edge portions, and are integrally connected and fixed as a pressure detecting portion 110.

The pressure detection element 41 attached to the inner surface of the top wall 1b of the base 1 can be, for example, a piezo element. A piezo element is a kind of ferroelectric substance and is also called a piezoelectric element, and is an element having a characteristic of generating a voltage when a force such as vibration or pressure is applied, and conversely expanding and contracting when a voltage is applied.
Bonding pads (terminals: not shown) of the pressure detection element 41 are electrically connected by lead wires 43 extending through through holes 42 formed in the base 1 and bonding wires 48, and the lead pins 43 are connected to the substrate 45. Has been. The through hole 42 of the base 1 is sealed so that there is no oil leakage by a hermetic seal portion 44 using glass.
The connector 46 is attached to the substrate 45, and power is supplied from the outside to the pressure detection element 41 through the bonding wire 48, the lead pin 43, the substrate 45, the connector 46 and the lead wire 47, and pressure detection is performed. A pressure signal output from the element 41 is extracted to the outside.

  The lead pin 43 and the lead wire 47 are offset in a direction intersecting with the drawing direction. Therefore, the connection between the lead pin 43 and the lead wire 47 is made through the substrate 45. By connecting with the substrate 45, the lead wire 47 can be drawn out to the central axis of the pressure sensor 100. That is, handling of the pressure sensor 100 can be facilitated regardless of the installation angle of the pressure sensor 100.

The connector connecting portion 120 includes a cover 60 that accommodates the pressure detecting portion 110 so as to be fitted to the base 1 from the outside and cover the side of the receiving member 2. The cover 60 also serves as a connector case that covers the substrate 45 and the connector 46.
The cover 60 is a member made of synthetic resin such as PPE, for example, and the end portion (upper end portion) on the side covering the connector 46 is reduced in diameter so as to surround the lead wire 47 to become a small diameter end portion 61. ing. On the other hand, an end portion side that accommodates the pressure detection unit 110 is formed with a large-diameter end portion 63 that has an increased inner diameter and extends in a cylindrical skirt shape.
After the outer peripheral portion of the pressure detection unit 110 is brought into contact with the stepped portion provided on the inner wall of the cover 60, both end openings of the cover 60 (opening end A on the small diameter end portion 61 side and opening on the large diameter end portion 63 side). Resin is filled and solidified from the end B), whereby the pressure detector 110 is fixed inside the cover 60, and at the same time, both end sides A and B of the cover 60 are sealed. By these things, the pressure detection part 110 can be made into a waterproof structure.

As described above, the deformation suppressing member 5 that suppresses excessive deformation of the diaphragm 3 is provided in the pressure receiving space 31, but the deformation suppressing member 5 contacts before the diaphragm 3 is excessively deformed and broken. Thus, the diaphragm 3 is disposed at a position where damage to the diaphragm 3 can be prevented.
With such a configuration, the pressure sensor 100 according to the present invention, even if oil leaks from the hermetic seal portion 44 that seals the pressure receiving space 31 of the pressure detection unit 110 and the oil in the pressure receiving space 31 is insufficient, When the deformation suppressing member 5 suppresses excessive deformation of the diaphragm 3, it is possible to prevent the diaphragm 3 from being damaged.

FIG. 2 is a plan view of the deformation suppressing member 5 applied to the pressure sensor 100 according to the first embodiment of the present invention.
As shown in FIGS. 1 and 2, the deformation suppressing member 5 includes a plate-like portion (plate-like member) 51, and one or a plurality of through holes 52 are formed in the central portion of the plate-like portion 51. These one or more through holes 52 are two spaces (a space on the diaphragm 3 side and a pressure detection element 41 side on the deformation suppression member 5 bordered by the deformation suppression member 5 when arranged in the pressure receiving space 31). By communicating the (space), it has a function of transmitting the pressure to the oil in the pressure receiving space 31 added from the diaphragm 3 to the pressure detecting element 41.
The plate-like portion 51 has a shape in which a concave surface is formed in a cross section by a saddle-like region near the outer periphery, an inclined region inside the saddle-like region, and a flat region further inside the inclined region (see FIG. 1). . Further, in the first embodiment, the deformation suppressing member 5 is integrated by being welded with the flange-shaped region of the outer peripheral portion sandwiched between the base 1 and the receiving member 2 together with the diaphragm 3.
Here, although FIGS. 1 and 2 show the case where there is one inclined region, a plurality of inclined regions may be formed to form the concave surface. The flat region may be a curved surface as well as a flat surface.
The deformation suppressing member 5 applied to the pressure sensor 100 of the present invention has the above-described configuration, so that when the diaphragm 3 is deformed by being loaded with the fluid pressure introduced into the pressurized space 12, no load is applied. The diaphragm 3 is deformed along the concave surface arranged at a predetermined position or distance from the state, and excessive deformation can be suppressed to prevent breakage.

Next, the outline of the pressure sensor according to the second embodiment of the present invention will be described with reference to FIGS.
Here, FIG. 3 is a diagram showing the pressure detection unit 210 in the second embodiment, FIG. 3A is a longitudinal sectional view of the pressure detection unit 210, and FIG. 3B is a diagram of FIG. It is sectional drawing in XX. FIG. 4 is a view showing an outline of the deformation suppressing member 50 applied to the second embodiment, FIG. 4 (A) is a plan view of the deformation suppressing member 50, and FIG. 4 (B) is FIG. 4 (A). It is sectional drawing in the YY line of FIG.

As shown in FIGS. 3 and 4, the deformation suppressing member 50 includes a plate-like portion (plate-like member) 501 and an annular leg portion 503 provided on the outer peripheral portion of the plate-like portion 501. Further, one or a plurality of (four in this example) through-holes 502 are formed in the central portion of the plate-like portion 501, and the leg portion 503 has an end portion on the opposite side to the diaphragm 3 of the leg portion 503. A plurality of cutout portions 504 are formed by cutting out a part thereof. In short, the annular leg portion 503 has a flat surface on the side fixed to the plate-shaped portion 501, but the surface opposite to the surface fixed to the plate-shaped portion 501 has an uneven shape. Yes.
In the second embodiment, the leg portion 503 of the deformation suppressing member 50 is attached to the top wall 1b of the base 1 by welding or bonding. At that time, the deformation suppressing member 50 is arranged so that the notch portion 504 faces the hermetic seal portion 44 formed in the base 1, so that the leg portion 503 does not interfere with the hermetic seal portion 44. Yes. That is, the deformation suppressing member 50 is disposed and fixed in the pressure receiving space without increasing the area of the top wall 1b of the base 1 by forming the notch portion 504 and facing the hermetic seal portion 44. Is possible.
Further, the height of the deformation suppressing member 50 is such that when the unloaded diaphragm 3 is deformed by the fluid pressure introduced into the pressurized space 12, the plate-like portion 501 can contact the diaphragm 3 without breaking. It is set to become.
Here, as shown in FIGS. 3 and 4, in the second embodiment, the plate-like portion 501 and the leg portion 503 are illustrated as separate members integrated, but a single member is used. The plate-like portion 501 and the leg portion 503 may be formed by bending. Further, the plate-like portion 501 and the leg portion 503 may be made of the same material or different materials. In particular, if the leg portion 503 is formed of a material such as resin and is bonded to the base 1, the weight of the deformation suppressing member 50 and the pressure sensor as a whole can be reduced as compared with the case where the leg portion 503 is formed of a material such as metal. .
A pressure sensor is configured using the pressure detection unit 210, the substrate 45, the connector 46, the lead wire 47, the resin cover 60, and the like as shown in FIG. The same applies to pressure detectors 310 and 410 described later.

According to the second embodiment, the diameter of the deformation suppressing member 50 can be reduced. Further, since the deformation suppressing member 5 is directly attached to the top wall 1 b of the base 1, it is necessary to position the deformation suppressing member 50 between the base 1 and the receiving member 2 when assembling the pressure detection unit 210. In addition, the construction of circumferential welding can be simplified.
Although it has been described that one or a plurality of through holes 502 are provided in the central portion of the plate-like portion 501, the space inside and outside the deformation suppressing member 50 can be communicated via the notch portion 504. The through hole 502 may be omitted.
Further, if the leg portion 503 is arranged outside the hermetic seal portion 44, only the through hole 502 can be formed, and the notch portion 504 can be omitted.

FIG. 5 is a vertical cross-sectional view of the pressure detection unit 310 and the components in the vicinity thereof in the third embodiment of the present invention.
As shown in FIG. 5, the deformation suppressing member 60 is formed into a plate shape by, for example, stainless steel, and has a bowl-shaped area near the outer periphery thereof, an inclined area inside the bowl-shaped area, and a flat area further inside the inclined area. Thus, a concave surface is formed in the cross section. One or a plurality of through holes as shown in FIG. 2 are formed in the flat region. On the other hand, an annular step portion 1c is formed at the intermediate portion of the flange portion 1a on the base 1x of the pressure detection portion 310, and the flange-shaped region of the deformation suppressing member 60 is brought into contact with the step portion 1c, for example, welding Etc. are joined.
In the third embodiment, the flat region of the deformation suppressing member 60 is flat when the unloaded diaphragm 3 is deformed by being loaded with fluid pressure introduced into the pressurized space 12. It is set so that the region can be touched.
According to the third example, since the deformation suppressing member 60 can be welded to the step 1c of the base 1x in advance and then the base 1x, the receiving member 2, and the diaphragm 3 can be welded, the pressure detection unit 310 is assembled. At this time, it is not necessary to position the deformation suppressing member 60 between the base 1x and the receiving member 2 and the circumferential welding work can be simplified.
Further, since the labor for positioning the flange-shaped region of the deformation suppressing member 60 when joining the stepped portion 1c of the base 1x can be saved, the entire assembly operation of the pressure detecting unit 310 can be simplified.

FIG. 6 is a vertical cross-sectional view of the pressure detection unit 410 and components in the vicinity thereof in the fourth embodiment of the present invention.
As shown in FIG. 6, the deformation suppressing member 70 includes a plate-like portion (plate-like member) and leg portions 71 provided on the outer peripheral portion of the plate-like portion, and has a plate shape as a whole. Although not shown, one or a plurality of through holes as shown in FIG. 2 are formed in the central portion of the plate-like portion.
In the fourth embodiment, the leg portion 71 of the deformation suppressing member 70 is formed so that the outer diameter of the end portion thereof is substantially the same as the inner diameter of the flange portion 1a of the base 1, and the end portion of the leg portion is formed. Is not bonded (fixed) to the base 1. That is, the deformation suppressing member 5 is slidably in contact with the flange 1a in the pressure receiving space 31 of the pressure detection unit 110 so as to be freely movable in the vertical direction in FIG. 6 (the central axis direction of the pressure detection unit 410). It is configured. Further, the height of the leg portion 71 is such that when the diaphragm 3 in an unloaded state is deformed by the fluid pressure introduced into the pressurizing space 12, the diaphragm 3 does not break and the plate-like portion can come into contact with it. It is set to be.
According to the fourth embodiment, since it is not necessary to join and fix the deformation suppressing member 70 to the base 1, the assembly process of the pressure detection unit 410 can be simplified.

7A to 7C are plan views showing modifications of the deformation suppressing member 5 applied to the pressure sensor 100 according to the first embodiment of the present invention.
In FIG. 2, although the through-hole 52 formed in the deformation | transformation suppression member 5 illustrated what was formed as four circular through-holes in the center part of the flat area | region of the plate-shaped part 51, FIG. As shown to a), you may arrange | position the shape of the four through-holes 52a radially as an ellipse or an ellipse. Further, as shown in FIG. 7 (b) or FIG. 7 (c), five or more small-diameter through holes 52b may be arranged, or large-diameter through holes 52c may be formed in the central portion. Good.
Note that the through holes 52a to 52c shown in FIGS. 7A to 7C are merely examples, and as described above, the deformation suppressing member 5 applied to the present invention suppresses excessive deformation of the diaphragm 3. Any shape, size, number and arrangement of the through holes 52 can be adopted as long as the function of transmitting pressure to the pressure detecting element 41 in the pressure receiving space 31 can be achieved.
Similarly, in the embodiments shown in FIGS. 3 to 6, the shape and the number of through holes can be changed as appropriate.

The pressure sensor of the present invention has the structure as described above, but various modifications are possible as long as it has the configuration described in the claims of the present invention.
For example, the deformation suppressing member has been described as being provided with through holes 52, 52a to 52c, 502 in order to communicate two spaces partitioned by the deformation suppressing member when arranged in the pressure receiving space 31. The present invention is not particularly limited to this mode, and a band-shaped cut is made from the outer peripheral portion of the plate-like deformation suppressing member, and the space on the diaphragm 3 side of the pressure receiving space 31 and the pressure detection element through the cut. The space on the 41 side may be communicated.
Further, a lattice-shaped opening or a wire mesh (hereinafter referred to as “mesh shape”) portion may be provided in a part of the deformation suppressing member, and the entire deformation suppressing member may be mesh-shaped.
Further, the cover may be formed in a multi-stage shape with steps, and the whole can be inclined in a tapered shape. On the other hand, regarding the specific shapes of the base and the receiving member, it is obvious that various modifications can be made to the shape and the like as long as the function as the pressure detection unit is not impaired and the fixing strength with the cover is not impaired. .

1, 1x base 1a collar 1b top wall 1c step 2 receiving member (flow pipe connecting member)
2a ridge part 3 diaphragm 4 welded part 5, 50, 60, 70 deformation suppressing member 11 fluid inflow pipe 12 pressure space 31 pressure receiving space 41 pressure detecting element 42 through hole 43 lead pin 44 hermetic seal part 45 substrate 46 connector 47 lead wire 51 Plate-like part 52, 52a-52c, 502 Through-hole 53 Leg part 60 Cover 61 Small diameter end part 63 Large diameter end part 100 Pressure sensor 110, 210, 310, 410 Pressure detection part 120 Connector connection part

Claims (2)

A pressure receiving space in which oil is enclosed is formed between the diaphragm and the diaphragm, and a pressure detection element is provided in the pressure receiving space, and a fluid inflow is provided to face the base with the diaphragm interposed therebetween. A pressure detection unit integrally connected to a receiving member in which a pressurizing space is formed between the diaphragm and the diaphragm through which the pressure is introduced through the fluid inflow pipe, and the pressure detection unit In a pressure sensor in which a lead pin connected to the base is sealed by a hermetic seal portion with respect to a through hole provided in the base,
In the pressure receiving space between the diaphragm and the base, a deformation suppressing member having a contact surface that suppresses deformation of the diaphragm is further arranged ,
The base includes a top wall and a collar that stands around the top wall,
The deformation suppression member is slidably in contact with the inner surface of the flange portion,
A pressure sensor characterized by that. The pressure sensor according to claim 1, wherein the deformation suppressing member has at least one through hole, groove, or mesh portion.

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