WO2014203647A1

WO2014203647A1 - Pressure detector

Info

Publication number: WO2014203647A1
Application number: PCT/JP2014/062547
Authority: WO
Inventors: 真之日尾; 風間　敦; 準二小野塚; 彰夫保川
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2013-06-20
Filing date: 2014-05-12
Publication date: 2014-12-24
Also published as: JP6147110B2; JP2015004566A

Abstract

To provide a pressure detector capable of reducing strain in the y-axis direction and enhancing the output sensitivity of a strain-detecting element, in a pressure measurement device (100) having a strain-generating body (25) that has pressure introduced from a pressure introduction hole (12ha) via a diaphragm (14) applied thereto and generates strain in accordance with the pressure and a strain-detecting element (16) joined to the surface of the strain-generating body (25) opposite from the pressure-receiving surface of the strain-generating body (25), on the surface of the diaphragm (14) side of the strain-generating body (25), a rib (25L1) formed along the y-axis direction in the center in the x-axis direction and a protrusion (30) in the center thereof are provided and ribs (25L2a, 25L2b) formed along the y-axis direction on both ends in the x-axis direction are provided and on the strain-detecting element (16) side of the strain-generating body (25), a plurality of electronic components (28) are provided, via a substrate (17), so as to be symmetrical around the central axis. The ribs (25L1, 25L2a, 25L2b) reduce the y-axis strain of the strain-generating body (25) and make it possible to maximize the output sensitivity of the strain-detecting element (16).

Description

Pressure detection device

The present invention relates to a pressure detection device mounted on various devices to be measured to detect pressure.

FIG. 8 shows an example of a conventional pressure detection device having a strain generating element that generates strain by receiving pressure from a pressure medium, and a strain detection element that detects strain generated by the strain generating body. The pressure measurement device 200 of FIG. 8 is configured as, for example, a high pressure sensor mounted on a vehicle, and is used to measure the fuel pressure of the engine, the brake hydraulic pressure, various gas pressures, and the like.

In the pressure measuring device 200 of FIG. 8, 11 is a pressure port into which pressure is introduced. The pressure port 11 has a hollow cylindrical pressure introducing portion 12 in which a pressure introducing port 12a is formed at one end in the axial direction, and a cylindrical flange, for example, formed at the other axial end (upper portion) of the pressure introducing portion 12 13 and a diaphragm 14 erected at a central portion of the flange 13.

The pressure introducing hole 12ha of the pressure introducing portion 12 is continuously bored to a portion slightly lower than the central portion of the flange 13 and the upper surface of the diaphragm 14.

On the upper surface of the diaphragm 14, a rectangular flat plate shaped strain generating body 15 which is deformed and distorted by the pressure introduced through the pressure introducing hole 12ha is disposed. A plurality of strain resistance bridges that output electric signals according to the deformation (strain) of the strain generating body 15 are provided at substantially the center of the surface opposite to the pressure receiving surface (the surface on the diaphragm 14 side) of the strain generating body 15. The distortion detection element 16 is joined.

The strain detection element 16 is configured as, for example, a semiconductor chip in which a plurality of strain resistance bridges are provided on one chip, and outputs a difference between strain in the x-axis direction and strain in the y-axis direction.

A substrate 17 is provided on a portion other than the strain detection element 16 on the surface opposite to the pressure receiving surface of the strain generating body 15. On the substrate 17, a circuit for amplifying and processing each detection signal output from the strain detection element 16, various electronic components, a capacitor 18 and the like are mounted.

On the upper surface of the outer peripheral portion of the flange 13, the peripheral edge of one open end of the cover 19 covering the diaphragm 14, the strain generating body 15, the strain detection element 16, the substrate 17 and the capacitor 18 is fixed. .

A predetermined diameter range from the center of the closing plate 19a closing the other axial direction of the cover 19 is notched, and the notched portion is formed of, for example, a resin and detected by the pressure measuring device 200 A connector 20 for outputting the pressure value to the outside is inserted.

One end of the connector 20 is fixed to the cover 19 in the cover 19, and the other end of the connector 20 is exposed to the outside from the cover 19.

Inside the connector 20, for example, a rod-like terminal 21 inserted by insert molding is provided. The terminal 21 comprises, for example, three terminals for power supply, grounding, and signal output, one end of each terminal 21 is connected to the substrate 17 and the other end is connected to an external connector (not shown). Is electrically connected to the ECU or the like of the automobile via the wiring member.

Further, FIG. 9 shows another example of the conventional pressure detection device, and the same parts as FIG. 8 are indicated by the same reference numerals. In FIG. 9, the strain detection element 16 is directly bonded to the diaphragm 24 provided with a rectangular groove without using the strain generating body 15 of FIG. 8, and the other parts are configured in the same manner as FIG. There is.

That is, the tip portion 12hbt of the pressure introducing hole of the pressure introducing portion 12 facing the strain sensing element 16 on the diaphragm 24 side is formed identical to the rectangular groove shape of the diaphragm 24 and the diaphragm 24 facing the tip portion 12hbt The strain detection element 16 is disposed directly on the upper surface.

In the configuration of FIG. 9, the rectangular groove of the diaphragm 24 causes a distortion difference in the x direction −y direction in the diaphragm 24. Further, since the diaphragm 24 is provided with a rectangular groove, it takes time and effort for forming.

Moreover, as a conventional pressure detection apparatus, the thing of patent document 1, 2 is proposed, for example.

In Patent Document 1, “a diaphragm provided on the main body and a strain gauge provided on one surface of the insulating substrate, and the diaphragm is deformed with the diaphragm on the side opposite to the pressure receiving side opposite to the pressure receiving side. A pressure sensor comprising a gauge substrate mounted to

Further, in Patent Document 2, “a load sensor having a thin plate-like sensor plate and a plurality of strain gauges attached to the sensor plate, the sensor plate has both ends in one axial direction of the sensor plate The fixed part is fixed to an arbitrary object, while the central point thereof is a transmission part for transmitting displacement or load to the sensor plate, and the strain gauge is positioned in point symmetry with respect to the central point. Strain gauges arranged at a point symmetrical position are electrically connected in parallel or in series to form a gauge pair, and each gauge pair is electrically connected in series, and these strain gauges are used. A load sensor characterized in that a bridge circuit is configured.

JP-A-8-62075 Re-issued patent WO2006 / 006677

In the conventional pressure detection devices including Patent Documents 1 and 2, the output sensitivity of the strain detection element determined by the difference between the x-axis direction strain and the y-axis direction strain is poor due to the influence of the strain in the y-axis direction.

The present invention solves the above problem, and an object thereof is to provide a pressure detection device capable of reducing the strain in the y-axis direction to improve the output sensitivity of the strain detection element.

In order to solve the above problems, for example, the configuration described in the claims is adopted. Although the present application includes a plurality of means for solving the above problems, one example is “a pressure detection device mounted on a device to be measured, in which the pressure of the pressure medium is applied through a diaphragm, In a pressure detection device having a strain generating element that generates strain according to pressure and a strain detection element joined to a surface opposite to the pressure receiving surface of the strain generating body,
The strain generating body is formed in a rectangular shape having a plane formed by the x axis and the y axis, and a rib is formed along the y axis on the pressure receiving surface of the strain generating body.

According to the present invention, the strain in the y-axis direction of the strain generating body is reduced by the rib, and the output sensitivity of the strain detection element can be maximized. Configurations and effects other than those described above will be apparent from the following description of the embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS The cross-sectional block diagram of the whole pressure measurement apparatus by one Embodiment of this invention. FIG. 2 is a perspective view of a strain generating body which is a main part of FIG. 1; Fig. 2 shows the joined state of the strain-generating body and the diaphragm, which are the main parts of Fig. 1, (a) is a perspective view of the main parts, (b) is a cross-sectional view of the embodiment of surface bonding, (c) is the embodiment of point bonding Cross section. Explanatory drawing which shows a deformation | transformation body being deformed by received pressure in embodiment of this invention. The initial state by the rib height in a pressure detection device is represented, and (a) is an essential part sectional view in the case of rib height on the center side> rib height on both sides in the embodiment of the present invention, (b) is the center Principal part sectional drawing in case of rib height of the side <rib height of the both ends side. The distortion detection element which is the principal part of FIG. 1, distortion-generating body, and a diaphragm are represented, (a) is a principal part perspective view, (b) is sectional drawing at the time of pressurization. The distortion detection element in the other embodiment example of this invention, an elastic body, and a diaphragm are represented, (a) is a principal part perspective view, (b) is sectional drawing at the time of pressurization. The whole block diagram which shows an example of the conventional pressure measurement apparatus. The other example of the conventional pressure measuring device is shown, (a) is a principal part top view, (b) is DD sectional drawing of (a).

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. FIG. 1 shows the entire configuration of a pressure measuring device 100 in an embodiment in which the present invention is applied to the pressure measuring device of FIG. 8, and the same parts as FIG. 8 are indicated by the same reference numerals.

On an upper surface of the diaphragm 14, a straining body 25 in which ribs 25 L 1, 25 L 2 a, 25 L 2 b and a projection 30 are formed is provided. The strain detection element 16 is joined to the center of the surface of the strain generating body 25 opposite to the diaphragm 14, and a plurality of electronic components 28 are arranged symmetrically from the central axis around the strain detection element 16 via the substrate 17. It is set up.

The strain generating body 25 is deformed by the pressure introduced through the pressure introducing hole 12ha to cause distortion, and the strain detection element 16 outputs a plurality of strains that output electric signals according to the deformation (strain) of the strain generating body 25. It has a resistive bridge.

The strain generating body 25 is formed in a rectangular shape having a plane by the x axis and the y axis as shown in FIG. 2 which is shown upside down with respect to FIG. 1, and the x axis direction center of the surface on the diaphragm 14 side. The rib 25L1 is formed along the y-axis, and the ribs 25L2a and 25L2b are formed along the y-axis at both ends in the x-axis direction. A protrusion 30 is provided at the center of the central rib 25L1 in the y-axis direction.

Therefore, in the strain generating body 25, the end portion (end point) of the protrusion 30 protruding from the central rib 25 L 1 and the end surface of the ribs 25 L 2 a and 25 L 2 b on both sides facing the diaphragm 14 are the diaphragm 14. In contact, only the central rib 25L1 (the protrusion 30) is welded, for example, by metal. Not limited to this, the end faces of the ribs 25L2a and 25L2b at both ends may also be welded to the diaphragm 14.

The ribs 25L1, 25L2a, 25L2b provided along the y-axis direction of the strain-generating body 25 reduce the strain in the y-axis direction of the strain-generating body 25 when deformation occurs due to pressure, The output sensitivity of the distortion detection element 16 determined by the difference in y-axis direction distortion can be maximized.

The output sensitivity of the strain detection element 16 can be adjusted by changing the length of the ribs 25L1, 25L2a, 25L2b. In addition, the air gap between the ribs 25L1 and 25L2a and the air gap between the ribs 25L1 and 25L2b are easily distorted.

Further, since the joint between the projection 30 provided at the central portion of the central rib 25L1 and the diaphragm 14 is a point joint, the strain-generating body 25 is easily distorted, and a large amount of displacement can be obtained. The output sensitivity of 16 is enhanced.

The projection 30 may not be provided on the central rib 25L1. In this case, the end face of the central rib 25L1 is metal welded to the diaphragm 14, for example.

FIG. 3 shows the bonding of the diaphragm 14 and the strain generating body 25. When the projection 30 is not provided on the rib 25L1, the end face of the rib 25L1 and the diaphragm 14 are surface-bonded as shown in FIG. When the projection 30 is provided, the projection 30 and the diaphragm 14 are point-joined as shown in FIG. 3 (c). In FIG. 3, the substrate 17 on the strain generating body 25, the electronic component 28 and the like are not shown. In the case of the surface bonding of FIG. 3 (b), the displacement amount of the strain generating body 25 at the time of pressure application is smaller than in the case of the point bonding of FIG. 3 (c).

By arranging the plurality of electronic components 28 symmetrically on the straining body 25 from the central axis, the stress distribution of the straining body 25 at the time of pressing is kept uniform as shown in FIG. Be FIG. 4 shows the deformation of the strain generating body 25 at the time of pressing, and the protrusion 30 at the tip of the rib 25L1 on the center side and the substrate 17 between the strain generating body 25 and the electronic component 28 are not shown. There is.

By arranging the electronic components 28 symmetrically with respect to the central axis in this manner, the electronic components 28 and the strain generating body 25 can be integrated, and the productivity is improved.

The height relationship between the central rib 25L1 and the ribs 25L2a (b) on both ends is set as follows: rib 25L1 height> rib 25L2a (b) height, as shown in FIG. 5 (a). FIG. 5 shows the initial state according to the rib height, and only the diaphragm 14, the strain generating body 25 and the strain detection element 16 are illustrated.

By setting as shown in FIG. 5A, tension can be generated in advance in the strain detection element 16 in the initial stage before pressurization (preload can be applied), and strain can be detected even by pressurization. The output of the element 16 can be stabilized.

On the other hand, when the rib 25L1 height <the rib 25L2a (b) height is set as shown in FIG. 5B, an inflection point at which the strain detection element 16 becomes compression → tension by applying pressure. As a result, the output becomes unstable at that inflection point.

Further, the ribs may be provided only on the central side rib 25L1, and the ribs 25L2a and 25L2b on both end sides may not be provided. Even in this case, a large amount of displacement is obtained in the strain generating body 25, and the output sensitivity of the strain detection element 16 is high.

FIG. 6 shows the deformation of the strain-generating body 25 under pressure when the ribs 25L2a and 25L2b are respectively provided at both ends of the strain-producing body 25 in the x-axis direction and one rib 25L1 is provided at the center side. The portion 30, the substrate 17, the electronic component 28, and the like are not shown.

As shown in FIG. 6B, in the case where there is one rib 25L1 on the center side in the x-axis direction, a three-point bending state is obtained at the time of pressure application, and a large amount of displacement can be obtained in the strain generating body 25. The number of ribs provided along the y-axis direction of the strain generating body 25 may be four or more. For example, as shown in FIG. 7 showing the deformation of the strain generating body 25 at the time of pressure application, the ribs provided on the center side in the x-axis direction may be two ribs 25L1a and 25L1b separated by a predetermined distance. In FIG. 7, the protrusion 30, the substrate 17, the electronic component 28 and the like are not shown.

In the case of FIG. 7 (b), a four-point bending state occurs at the time of pressurization, and stress concentration is reduced. In addition, there is robustness against positional displacement of the strain detection element 16 disposed on the strain generating body 25. If more than four ribs are provided, the ribs on the center side in the x-axis direction (25L1a and 25L1b in FIG. 7B) are divided, so the total number of ribs is an even number (even bending) And). As described above, by setting the number of ribs provided on the strain generating body 25 to an even number of four or more, stress concentration is further reduced.

11 Pressure port 12 Pressure introduction portion 12a Pressure introduction port 12ha Pressure introduction hole 12h bt Tip portion 13 Flange 14 Diaphragm 15, distortion body 16 Strain detection element 17 Substrate 18 Capacitor 19 cover 19a: Blocking plate 20: Connector 21: Terminal 25L1, 25L1a, 25L1b, 25L2a, 25L2b: Rib 28: Electronic part 30: Protrusion part 100, 200: Pressure measurement device

Claims

A pressure detection device mounted on a device to be measured, wherein a pressure medium of a pressure medium is applied through a diaphragm, and a strain generating body that generates a strain according to the pressure and a pressure receiving surface opposite to the pressure receiving surface of the strain generating body A pressure sensing device having a strain sensing element bonded to the surface,
The pressure detecting device is characterized in that the strain generating body is formed in a rectangular shape having a plane formed by the x axis and the y axis, and a rib along the y axis is formed on a pressure receiving surface of the strain generating body.
The pressure detection device according to claim 1, wherein the rib is provided at the center of the strain generating body in the x-axis direction.
The pressure detection device according to claim 2, wherein the rib is also provided on both ends of the strain generating body in the x-axis direction.
The pressure detection device according to claim 3, wherein the height of the rib in the center in the x-axis direction is formed higher than the height of the ribs in both ends in the x-axis direction.
The pressure detection device according to any one of claims 2 to 4, wherein a protrusion is provided at the center in the y-axis direction of the rib at the center in the x-axis direction.
The pressure detection device according to any one of claims 1 to 5, wherein four or more even-numbered ribs are provided.
7. The electronic apparatus according to claim 1, wherein a plurality of electronic components are disposed symmetrically with respect to the central axis around the strain detection element on the strain detection element bonding surface of the strain generating body. Pressure detector as described.