JP4574324B2 - Strain generating body, physical quantity / electric quantity converter, and method of manufacturing strain generating body - Google Patents

Description

  The present invention includes a strain generating body that generates strain upon receiving physical quantities such as acceleration, pressure, load, displacement, and the like, the strain generating body, and a resistance change corresponding to the strain that is attached to the strain generating section of the strain generating body. The present invention relates to a physical quantity / electric quantity converter such as an acceleration converter, a pressure converter, a load converter, a displacement converter, etc. for converting the physical quantity into an electric quantity and a method for producing a strain generating body.

An acceleration converter, which is one of the physical quantity / electric quantity converters, performs crash tests and steering stability tests on automobiles, measures the impact strength of structures, and measures acceleration waveforms in vibrations generated in structures. It is used over a wide range, such as when performing analysis. Some conventional acceleration transducers used in this way have the following structure.
That is, the strain-generating body constituting the acceleration transducer is, for example, a cross-beam-fixed end-fixed type, and its peripheral portion is fixed to a driven portion that moves integrally with the object to be measured, and in the central portion. A weight portion is attached, and the weight portion relatively displaces the position of the central portion with respect to the peripheral portion of the strain body by the acceleration motion of the object to be measured. Between the peripheral part and the central part of the strain generating body, it is formed in a beam shape, and among the parts made into the beam shape, two strain generating parts near the peripheral part and two strain generating parts near the central part are formed. The four strain gauges are attached by bonding or other means, and the back side portion corresponding to the portion to which each strain gauge of each strain generating portion is attached has a concave groove having a semicircular cross section. Two strips are turned in a ring shape around the axis of the strain body. That is, the strained portion is thinned by forming these concave grooves.

  When the strain generating body receives acceleration from the measurement target due to vibration or shock of the measured object, the central portion of the strain generating body is displaced and distortion occurs in the beam-shaped portion. For example, when the central part of the strain generating body bends downward, the two strain generating parts near the peripheral part generate tensile strain, and the strain output of the strain gauge attached thereto becomes a positive value, The two strain generating portions generate compressive strain, and the strain output of the strain gauge attached thereto has a negative value (see, for example, Patent Document 1).

JP-A-60-256066 (page 4, lower left column, line 16 to page 5, lower left column, line 8, line 2)

  As shown schematically in FIG. 16, the acceleration converter described in Patent Document 1 described above is such that when the acceleration in the vertical direction is applied to the driven unit 1 due to vibration, impact, etc. of the measured object, FIG. 16 vibrates as indicated by the solid line arrow. Accordingly, compressive strain or tensile strain based on the vertical movement of the weight portion 2 is generated in the beam-shaped portion 3. However, the vibration of the object to be measured may include not only the vertical direction but also the acceleration in the oblique direction. In such a case, as shown by the arc-shaped broken line arrow in FIG. A compressive strain or a tensile strain based on the left-right movement (swing) of the portion 2 occurs. Therefore, the strain gauge outputs not only a value based on the strain corresponding to the vertical acceleration to be detected but also a value based on the strain corresponding to the complex deformation of the beam-like portion 3. This phenomenon is called “interference”. Note that FIG. 16 does not faithfully represent the actual behavior of the weight portion 2, but exaggeratedly expresses it to give a specific image.

Therefore, in some conventional acceleration transducers, strain gauges are attached to both the front and back surfaces of the beam-like portion 3, and these strain gauges are assembled into a bridge, and the resistance value obtained from each strain gauge is changed. In some cases, the influence of the interference is removed by electrically processing the. However, the movement of the weight portion 2 is not simple, and the deformation of the beam-like portion 3 according to the movement of the weight portion 2 is not simple. However, there is a case where the influence of the interference cannot be completely removed even if the processing is performed, and the reliability of the obtained data cannot be said to be high. Further, not limited to the good Una form of the acceleration transducer of FIG. 16, the weight portion 2 is one side of the beam-shaped part 3, for example, there are also similar problems in the form provided only on the lower side.
Further, in the acceleration converter described in Patent Document 1, the vibration mode is not stable, and it is difficult to obtain good frequency characteristics.

In recent years, there has been a demand for further downsizing of the acceleration converter due to various factors such as downsizing of the object to be measured and the tendency of structure miniaturization / complication. However, in the acceleration converter described in Patent Document 1 described above, a strain gauge formed by bonding a resistor element to a gauge base is bonded to a strain generating portion. In this process, the strain gauge bonding surface is polished. A process, a step of degreasing and cleaning the strain gauge bonding surface, a step of applying an adhesive to one or both of the back surface of the strain gauge and the strain gauge bonding surface, and the strain gauge bonding surface until the adhesive is cured. The process must be performed manually by the operator. Therefore, the more strain gauges become smaller and the strain gauges become smaller as the acceleration transducers become smaller, the more care must be taken to process each process. There was a problem that it took much time to assemble the acceleration transducer.
Moreover, since the acceleration converter described in Patent Document 1 is assembled with machined parts machined by a machine, there is a limit to downsizing the acceleration converter. In particular, the strain-generating portion is made thin by forming a concave groove having a semicircular cross section in the back side portion of the beam-like portion, but in order to reduce the size of the acceleration converter, the strain-generating portion is made thinner. Although it is necessary, there is a limit to thinning by machining. Even if each part can be miniaturized, the shape of each part is miniaturized, so there is a risk that a large initial strain may occur during assembly and further damage may occur, resulting in poor yield. is there.

The problems described above are in other physical quantity / electric quantity converters such as a pressure converter that converts pressure into an electric quantity, a load converter that converts a load into an electric quantity, and a displacement converter that converts displacement into an electric quantity. Is almost true.
The present invention has been made in view of the above-described circumstances, can suppress displacement in a direction other than the direction of the physical quantity to be measured, can extremely reduce interference, and has a good yield during manufacturing. A strain generating body that can shorten the manufacturing time, can be mass-produced at low cost, has good durability, has good frequency characteristics, has good responsiveness, and can be downsized. It is an object of the present invention to provide an electric quantity converter, a method for producing a strain generating body, and a method for producing a physical quantity / electric quantity converter.
The object of claim 1 of the present invention is particularly good in that the displacement in the direction other than the direction of the physical quantity to be measured can be suppressed, the coherence can be extremely reduced, the response frequency range is wide and wide. Frequency characteristics can be obtained, miniaturization and high output can be achieved, and furthermore, the yield during manufacturing is good, the manufacturing time can be shortened, mass production can be performed at low cost, and durability Another object of the present invention is to provide a physical quantity / electric quantity converter that is good, has good responsiveness, and can realize low cost.

The purpose of the second aspect of the present invention, in particular, with stable damping characteristics can be obtained is to provide a good responsive physical quantity / electric quantity converters.

The object of claim 3 of the present invention is that, in particular, the displacement in a direction other than the direction of the physical quantity to be measured can be extremely reduced, the coherence can be extremely reduced, the production yield is good, and the production A method for producing a strain generating body capable of reducing time and mass production at low cost, having good durability, obtaining good frequency characteristics, good responsiveness, and realizing downsizing. It is to provide.
An object of claim 4 of the present invention is to provide a manufacturing method of a strain generating body having the above-mentioned characteristics by applying various processing methods.
The object of the fifth aspect of the present invention is to provide a method for producing a strain generating body that can be mass-produced at low cost.
An object of claim 6 of the present invention is to provide a method for producing a strain generating body having the above-described characteristics, in particular, using various removal methods .

In order to achieve the above-described object, the strain body according to the present invention described in claim 1
A pair of strain-generating plates made of a thin metal plate and having a strain-generating portion that receives a physical quantity and generates strain;
A plurality of weight plates made of a thin metal plate and constituting a weight portion supported by the strain plate by being integrated,
It consists of a thin plate of metal, and consists of a spacer plate inserted between the pair of strain-generating plates and the weight plate,
The two strain generating plates, the two spacer plates, and the plurality of weight plates are integrated in a stacked state so that the acceleration applied to the strain generating body can be detected. configuration was the cause Ibitsutai,
A plurality of strain gauges attached to the strain-generating portion of the strain-generating body;
A power supply electrode formed in the vicinity of the strain-generating portion of the strain-generating body, connected to each of the plurality of strain gauges to constitute a Wheatstone bridge circuit, and for supplying a bridge voltage to the Wheatstone bridge circuit, and the Wheatstone A bridge pattern having an output electrode for extracting an output voltage from the bridge circuit;
A substrate on which a plurality of electrodes connected to the power supply electrode and the output electrode constituting the bridge pattern and a pattern for connecting the plurality of electrodes and a plurality of metal wires constituting a cable are formed, respectively. ,
A one-end opening type casing in which a female screw is formed on the inner periphery in the vicinity of the opening;
A base fitted into the inner periphery of the casing and having a first O-ring fitted in a groove formed in the inner bottom surface;
An inner lid in which a second O-ring is fitted in a concave groove formed on the lower surface;
A ring nut screwed into the female screw of the casing;
A casing lid,
The plurality of strain gauges and the bridge pattern are formed in the base, and the strain body in which the substrate is connected to the bridge pattern is accommodated, and the inner lid is formed on the strain body and the substrate. The strain nut is fixed in the casing by screwing the ring nut into the female screw of the casing, and the strain body is cut off from the outside by fixing the casing lid. It is characterized by sealing .

The physical quantity / electric quantity converter according to the present invention described in claim 2 is the physical quantity / electric quantity converter according to claim 3,
The strain body is characterized in that the weight portion is formed in the center portion with a gap between the fixed portion on the periphery and the space of the strain body is filled with a viscous fluid. .
In order to achieve the above-described object, the manufacturing method of the strain body according to the present invention described in claim 3
With a thin metal plate, an annular part is arranged on the outer peripheral side, a small disk part is arranged in the center part, and four beams narrower than the diameter of the small disk part between the annular part and the small disk part A strain plate in which the portions are arranged in a cross shape, and a strain generating portion that receives a physical quantity at the inner end and the outer end of each beam portion and generates strain is integrally formed;
A large disk part that constitutes a weight part supported by the strain-generating plate by being integrated with a thin metal plate is disposed in the center, and an annular part on the outer peripheral side of the large disk part A narrow connecting portion is disposed at an angular position between the annular portion and the large disc portion so as not to overlap the cross-shaped beam portion of the strain plate. A plurality of integrally formed weight plates;
With a thin metal plate, a small disk portion as a space holding portion for holding the space between the strain generating plate and the weight portion is disposed on the center side, and an annular portion is disposed on the outer peripheral side, Spacers formed between the annular portion and the small disc portion, each having a narrow connecting portion at an angular position that does not overlap with the cross-shaped beam portion of the strain plate, and are integrally formed. Processing steps to produce each plate,
A joining step in which the strain plates are respectively arranged on both end sides of the plurality of weight plates via the spacer plates and integrated with each other;
Of the connecting portion between the large disc portion and the annular portion of the weight plate and the connecting portion between the small disc portion and the annular portion of the spacer plate, portions close to the annular portion are respectively removed. And a connecting portion removing step .

Method for producing a flexure element according to the present invention described in claim 4 is the method of claim 3, wherein the processing step, etching, laser processing, that produced by either machining It is a feature.
The method for producing a strain body according to the present invention described in claim 5 is the method according to claim 3 , wherein the joining step is any one of diffusion joining, brazing, electron beam welding, and laser welding. It is characterized by use.
Method for producing a flexure element according to the present invention described in claim 6 is the method of claim 3, wherein the connecting portion removal step, either a wire electric discharge machining, Les chromatography The processing and machining It is characterized by using.

According to the present invention, the displacement in a direction other than the direction of the physical quantity to be measured can be suppressed, interference can be extremely reduced, the manufacturing yield can be improved, and the manufacturing time can be shortened. Mass production at low cost, good durability, good frequency characteristics, good responsiveness, miniaturization can be realized, strain-generating body, physical quantity / electric quantity converter, strain-generating body A manufacturing method and a manufacturing method of a physical quantity / electric quantity converter can be provided.
That is, according to the strain generating body of claim 1 of the present invention, a pair of strain generating plates that are made of a thin metal plate and have a strain generating portion that receives a physical quantity and generates strain,
A plurality of weight plates made of a thin metal plate and constituting a weight portion supported by the strain plate by being integrated,
It consists of a thin plate of metal, and consists of a spacer plate inserted between the pair of strain-generating plates and the weight plate,
The two strain generating plates, the two spacer plates, and the plurality of weight plates are integrated in a stacked state so that the acceleration applied to the strain generating body can be detected. configuration was the cause Ibitsutai,
A plurality of strain gauges attached to the strain-generating portion of the strain-generating body;
A power supply electrode formed in the vicinity of the strain-generating portion of the strain-generating body, connected to each of the plurality of strain gauges to constitute a Wheatstone bridge circuit, and for supplying a bridge voltage to the Wheatstone bridge circuit, and the Wheatstone A bridge pattern having an output electrode for extracting an output voltage from the bridge circuit;
A substrate on which a plurality of electrodes connected to the power supply electrode and the output electrode constituting the bridge pattern and a pattern for connecting the plurality of electrodes and a plurality of metal wires constituting a cable are formed, respectively. ,
A one-end opening type casing in which a female screw is formed on the inner periphery in the vicinity of the opening;
A base fitted into the inner periphery of the casing and having a first O-ring fitted in a groove formed in the inner bottom surface;
An inner lid in which a second O-ring is fitted in a concave groove formed on the lower surface;
A ring nut screwed into the female screw of the casing;
A casing lid,
The plurality of strain gauges and the bridge pattern are formed in the base, and the strain body in which the substrate is connected to the bridge pattern is accommodated, and the inner lid is formed on the strain body and the substrate. The strain nut is fixed in the casing by screwing the ring nut into the female screw of the casing, and the strain body is cut off from the outside by fixing the casing lid. in by the sealing, it can be extremely small displacement in the direction other than the direction to be measured acceleration can be extremely reduced coherence, it is wide and extensive and good frequency characteristic response frequency range the resulting, it is possible to realize miniaturization and high output, good yield during manufacture, be mass-produced inexpensively and be able to shorten the production time It can, durability is good, can be realized cost reduction.

According to the physical quantity / electric quantity converter of claim 2 of the present invention, it is the converter of claim 1, wherein the strain generating body is placed in the central portion with a gap between the fixed portion and the peripheral fixed portion. A weight part is formed, and the space of the strain generating body is filled with a viscous fluid, so that a stable attenuation characteristic can be obtained and a responsive physical quantity / electric quantity converter may be realized. .
According to the manufacturing method of the strain body of claim 3 of the present invention, the annular portion is disposed on the outer peripheral side and the small disc portion is disposed in the central portion with a thin metal plate, and the annular portion and the small portion are disposed. Four beam parts narrower than the diameter of the small disk part are arranged between the disk parts in a cross shape, and a strain generating part that generates a strain by receiving physical quantities at the inner and outer ends of each beam part is provided. A strain plate formed integrally with each other;
A large disk part that constitutes a weight part supported by the strain-generating plate by being integrated with a thin metal plate is disposed in the center, and an annular part on the outer peripheral side of the large disk part A narrow connecting portion is disposed at an angular position between the annular portion and the large disc portion so as not to overlap the cross-shaped beam portion of the strain plate. A plurality of weight plates formed on,
With a thin metal plate, a small disk portion as a space holding portion for holding the space between the strain generating plate and the weight portion is disposed on the center side, and an annular portion is disposed on the outer peripheral side, Spacers formed between the annular portion and the small disc portion, each having a narrow connecting portion at an angular position that does not overlap with the cross-shaped beam portion of the strain plate, and are integrally formed. Processing steps to produce each plate,
A joining step in which the strain plates are respectively arranged on both end sides of the plurality of weight plates via the spacer plates and integrated with each other;
Of the connecting portion between the large disc portion and the annular portion of the weight plate and the connecting portion between the small disc portion and the annular portion of the spacer plate, portions close to the annular portion are respectively removed. The joint removal step , the displacement in the direction other than the direction of the physical quantity to be measured can be extremely reduced, the interference can be extremely reduced, the manufacturing yield is good, and the manufacturing time is improved. Can be manufactured at low cost, and can be mass-produced at low cost, with good durability, good frequency characteristics, good response, and downsizing.

According to the method for manufacturing a strain-generating body according to claim 4 of the present invention, it is possible to provide a method for manufacturing a strain-generating body having the characteristics described above, particularly by applying various processing methods.
According to the method for manufacturing a strain-generating body of claim 5 of the present invention, it is possible to provide a method for manufacturing a strain-generating body that can be mass-produced particularly at low cost.
According to the method for manufacturing a strain-generating body of claim 6 of the present invention, it is possible to provide a method for manufacturing a strain-generating body having the characteristics described above, particularly using various removal methods .

Hereinafter, based on the embodiment concerning the present invention, the physical quantity / quantity-of-electricity converter of the present invention is explained in detail with reference to drawings.
FIG. 1 is an enlarged cross-sectional view showing the external configuration of the acceleration converter according to the first embodiment of the present invention, and FIG. 2 is a plan view of the acceleration converter shown in FIG. A casing 11 of this acceleration converter is formed by integrally forming a main body portion 11a that has a rectangular parallelepiped shape (substantially square hook shape) with an upper end opening, and an overhang portion 11b that has a long rectangular cross section. Four (or two) attachment screw holes (attachment screw insertion holes) 11c are formed in the four corners of the casing 11, respectively. The mounting screws (not shown) inserted through the four (or two) screw holes 11c are screwed into the four (or two) female screw holes formed in the object to be measured. An acceleration transducer can be attached to the object to be measured. A base 12 having a cylindrical shape lower than the casing 11 is fitted to the inner periphery of the main body 11a. An O-ring 13 is fitted in the concave groove 12 a formed on the inner bottom surface of the base 12. Inside the base 12 is accommodated a strain generating body 14 whose overall shape is substantially cylindrical via an O-ring 13 between the bottom surface thereof. The detailed structure of the strain body 14 will be described later.

  As shown in FIG. 3, eight strain gauges SG1 to SG8 and a bridge pattern BP are formed on the upper surface of the strain generating body 14, respectively. The bridge pattern BP connects the strain gauges SG1 to SG8 so as to constitute the Wheatstone bridge circuit shown in FIG. The strain gauges SG1 to SG8 and the bridge pattern BP are formed on the upper surface of the strain generating body 14 by physical vapor deposition (PVD) such as sputtering or vacuum vapor deposition, and specific formation positions will be described later.

  The corresponding five electrodes P21 to P25 of the flexible substrate (or flexible printed circuit board) 15 shown in FIG. 5 are connected to the five electrodes P11 to P15 of the bridge pattern BP shown in FIG. 3 by soldering, respectively. 3 and 4, electrodes P11 and P14 are a + power supply electrode and a − power supply electrode for supplying a bridge voltage BV to the Wheatstone bridge circuit, and electrodes P15 and P12 are for extracting an output voltage eo from the Wheatstone bridge circuit. The + output electrode, the −output electrode, and the electrode P13 are ground electrodes. Five flexible foil patterns CP1 to CP5 are respectively formed on the flexible substrate 15, and electrodes P21 to P25 are respectively formed at one ends of the respective copper foil patterns CP1 to CP5, and the respective copper foil patterns CP1, CP2, Lands L11 and L12, L21 and L22, L31, L41, L42 and L51 are formed at the other ends of CP3, CP4 and CP5, respectively. As shown in FIG. 1, the flexible substrate 15 extends to the vicinity of the opening 11ba of the overhanging portion 11b. Although not shown in FIG. 1, the lands L11, L12, L21, L22, L31, L41, L42 and L51 is connected to each end of a plurality of metal wires (core wires) and shield wires protruding from the tip of the cable 22. The outer periphery of the overhang portion 11 b and the outer periphery of the tip end portion of the cable 22 are covered with a rubber cap 23.

  In FIG. 1, an inner lid 16 having a substantially ring shape is provided on the upper surface of the strain body 14. An O-ring 17 is fitted in the concave groove 16 a formed on the lower surface of the inner lid 16. In addition, a substantially circular through hole 16b is formed in a substantially central portion of the inner lid 16, and a sealing rubber 18 is fitted therein. The through hole 16b is for injecting a liquid such as silicon oil or an inert gas such as argon or nitrogen (both not shown) that fills the gap AP formed in the strain body 14 and functions as a damper. Is.

  A female thread is formed on the inner periphery of the casing 11 in the vicinity of the opening end, and a ring nut 19 is screwed together. The ring nut 19 is provided with circular through holes 19a and 19b in the axial direction, and two cylindrical fastening jig pins (not shown) are fitted in the circular through holes 19a or 19b. Thus, the ring nut 19 is tightened more firmly by turning. A pressing plate 20 having a substantially disc shape is placed on the upper surface of the sealing rubber 18, and a pressing plate is formed by firmly fixing a circular casing lid 21 to the upper end of the casing 11 with an adhesive. 20 presses the sealing rubber 18 and the confidentiality around the strain generating body 14 is maintained. As shown in FIG. 2, four circular through holes 21 a are formed at the four corners of the casing lid 21.

  Next, the detailed structure of the strain body 14 will be described. 6 is an enlarged plan view of the strain-generating body 14, FIG. 7 is an enlarged cross-sectional view of the strain-generating body 14, and FIG. 8 is an exploded perspective view of a state in which the strain-generating body 14 is joined. . Prior to joining, as shown in FIG. 8, the strain generating body 14 is composed of two strain generating plates 31, which are formed in a cross beam shape with a metal such as stainless steel, a spacer plate 32, and a plurality of weight plates. 33 is formed separately and then joined together. After joining, the strain-generating plate 31 has an annular portion 31a disposed on the outer peripheral side which is fixed with high rigidity, a small disc portion 31b disposed at the center portion, an annular portion 31a and a small annular portion 31a. Four beam portions 31c disposed between the disk portion 31b, and four strain generating portions 31d that are connected in a constricted state with the inner peripheral portion of the annular portion 31a and the outer end of each beam portion 31c. In addition, four strain-generating portions 31e are formed integrally with each other so that the inner end of each beam portion 31c and the small disk portion 31b are constricted. The width of each beam portion 31c is slightly narrower than the diameter of the small disk portion 31b. Each beam portion 31c is provided at an interval of 90 degrees with respect to the center of the small disk portion 31b.

  Of the two upper and lower strain generating plates 31, on the surface of each strain generating portion 31d and each strain generating portion 31e of the upper strain generating plate 31, as shown in FIG. The strain gauges SG1 to SG8 described above for detecting the bending strain of 31e are attached. Further, the bridge pattern BP connecting the strain gauges SG1 to SG8 has an annular portion 31a in which the portion opposite to the portion facing the flexible substrate 15 shown in FIG. In each of the beam portions 31c, the small disc portion 31b covers the central portion and the left and right directions in FIG. 3 so that the small disc portion 31b is covered in a substantially fan shape. Each is formed so as to cover almost the entire surface, leaving both ends in the direction. Two notches 31ab are formed at positions symmetrical with respect to the center of the small disk portion 31b of the annular portion 31a.

FIG. 8 is an exploded perspective view showing the strain-generating plate 31 formed by a method described later in a disassembled state.
In FIG. 8, the spacer plate 32 is a symmetric position with respect to the center of the annular portion 32a disposed on the outer peripheral side, the small disk portion 32b disposed in the center portion, and the small disk portion 32b. The inner end is connected to the outer periphery of the small disk portion 32b, and the outer end has two connecting portions 32c extending to the vicinity of the inner periphery of the annular portion 32a. Cutout portions 32ab are formed at positions that are symmetrical (180 degree intervals) with respect to the center of the small disk portion 32b of the annular portion 32a. The spacer plate 32 is provided in order to prevent the spacer plate 32 from colliding with the strain-generating plate 31 even if the weight portion W formed by joining a plurality of large disk portions 33b has a large amplitude. That is, a gap that does not prevent the weight portion W from being displaced by acceleration is provided. The weight plate 33 has an annular part 33a disposed on the outer peripheral side and a large disk part 33b disposed in the center. A gap AP is provided between the annular portion 33a and the large disc portion 33b on the same plane. Cutout portions 33ab are formed at positions (180 degree intervals) that are symmetrical with respect to the center of the large disk portion 33b of each annular portion 33a.

Next, a method for manufacturing the deformable portion T, the weight portion W, the fixed portion F, the spacer portion S, and the strain plate 14 constituting the strain body 14 for detecting acceleration will be described with reference to FIGS. 9 and 10. To do.
(1) First, a stainless steel plate having a thickness of 100 μm manufactured by cold rolling is formed into a thin plate having an arbitrary thickness by polishing.
(2) Next, the thin plate 41 is subjected to pretreatment (for example, alkaline degreasing, pickling, water washing and drying). Alkaline degreasing is a process for removing rolling oil and other contaminants attached to the surface of the thin plate 41. As shown in FIG. 9A, the pickling is a process of immersing the thin plate 41 in the pickling solution 43 filled in the liquid tank 42, neutralizing the alkali content remaining on the surface of the thin plate 41, and The purpose is to enhance the adhesion between the surface of the thin plate 41 and the organic resin by dissolving the oxide film and activating the surface of the thin plate 41. As the pickling solution 43, an aqueous solution containing one or more of hydrochloric acid, sulfuric acid, nitric acid and hydrofluoric acid is often used.

(3) Next, as shown in FIG. 9B, photoresist films 44a and 44b previously formed into a film shape are attached to the front surface 41a and the back surface 41b of the thin plate 41, respectively. The photoresist films 44a and 44b are, for example, casein or acrylic photosensitive organic resin.
(4) Next, as shown in FIG. 9C, on the photoresist films 44a and 44b, the annular portion 31a, the small disc portion 31b, and the four beam portions 31c of the strain plate 31 shown in FIG. After the exposure masks 45a and 45b for leaving the eight strain generating portions 31d and 31e are overlaid, ultraviolet rays are irradiated by the ultraviolet lamps 46a and 46b.
(5) Next, the intermediate processed product that has undergone the above-described steps (1) to (4) is developed by being immersed in a developer. As a result, the portions of the photoresist films 44a and 44b that have not been irradiated with the ultraviolet rays are melted and removed, and the portion of the thin plate 41 is exposed. As shown in FIG. 9D, the front surface 41a and the back surface of the thin plate 41 are exposed. Photoresist patterns 47a and 47b having the same planar shape as the exposure masks 45a and 45b are formed on 41b.

(6) Next, as shown in FIG. 10A, an etching solution 48 such as a ferric chloride solution is sprayed on the front surface 41a and the back surface 41b of the thin plate 41 on which the photoresist patterns 47a and 47b are formed. The intermediate workpiece 50 is obtained by performing spray etching processing by spraying more and dissolving the exposed portion of the thin plate 41.
(7) Next, as shown in FIG. 10B, the intermediate workpiece 50 is immersed in a stripping solution 51 to remove the photoresist patterns 47a and 47b, thereby obtaining an etched workpiece 52. In the case of this embodiment, the etched workpiece 52 is not a single strain plate 31 but an overall planar shape as shown in FIG. (In the example of FIG. 11, ten strain generating plates 31 are formed to be connected to the peripheral portion and the wire cutting scheduled portion 52a, and through holes 52b that are positioning holes in diffusion bonding described later are formed at the four corners. ing. In addition, about the manufacturing method of the spacer board 32 and the weight board 33 which comprise the strain body 14, it is the above except that the shape which each etching processed material should form differs, and the above-mentioned process (1) is not performed. Since it is the same as the manufacturing method of the distorted plate 31 performed, the description is omitted. The details of the etching process of stainless steel are disclosed in, for example, Japanese Patent Application Laid-Open Nos. 8-225960 and 2002-275541. This process is referred to as an “etching process”.

  Etched workpiece 52 as strain generating plate 31 obtained through steps (1) to (7) described above, and spacer plate obtained through steps (2) to (7) described above. The etched workpiece 53 as 32 and the etched workpiece 54 as the weight plate 33 are etched into the etched workpiece 52 as the strain plate 31 and the spacer plate 32 from below as shown in FIG. The workpiece 53, the plurality of etched workpieces 54 as the weight plate 33, the etched workpiece 53 as the spacer plate 32, and the etched workpiece 52 as the strain generating plate 31 are formed in the respective etched workpieces 52 to 54 in this order. Stack them so that the through-holes match. FIG. 12A is a plan view of a state in which the etched workpieces 52 to 54 are stacked, and FIG. 12B is a front view of a state in which the etched workpieces 52 to 54 are stacked. It should be noted that each of the etched workpieces 52 to 54 shown in FIG. 12A has a vertical dimension and a horizontal scale, and each of the etched workpieces 52 to 54 shown in FIG. Is not the same.

  FIG. 13 is a perspective view showing the order of stacking the semi-finished products 55 to 57 in a state where each of the etched workpieces 52 to 54 is configured and divided into a single piece. However, as can be seen by comparing FIG. 8 and FIG. 13, each semi-finished product 55 to 57 has a notch formed in each of the strain generating plate 31, the spacer plate 32 and the weight plate 33 in FIG. 8. 31ab, 32ab and 33ab are not formed. In the semi-finished product 56, the two connecting portions 32c are connected to the inner periphery of the annular portion 32a via two wire cut scheduled portions 56a. On the other hand, in the semi-finished product 57, the large disk part 33b is connected to the inner periphery of the annular part 33a via two wire cut scheduled parts 57a. In addition, each semi-finished product 55-57 shown in FIG. 13 is corresponded to what was obtained by excising the wire cut scheduled part 52a from the etching processed products 52-54 shown in FIG.

  Next, as shown in FIG. 14, diffusion-bonded apparatuses 52 to 54, which are stacked as shown in FIG. 12, and etched workpieces 52 to 54 in which cylindrical rods for positioning (not shown) are inserted into the matched through holes, are shown. The vacuum furnace 61 is placed in a vacuum furnace 61, and a predetermined vacuum degree is taken for a predetermined time, and then the temperature in the vacuum furnace 61 is heated to a solution temperature of stainless steel (for example, about 1050 ° C.) Pressurization is performed so that a predetermined pressure is applied to the bonding surfaces of the adjacent etched workpieces 52 to 54. Thereby, joining is performed by the diffusion of the elements between the adjacent etched workpieces 52 to 54 on the bonding surfaces of the adjacent etched workpieces 52 to 54. The details of stainless steel diffusion bonding are disclosed in, for example, Japanese Patent Application Laid-Open No. 62-199277. This process is referred to as a “diffusion bonding process”.

  Next, a method for forming a strain gauge and a bridge pattern will be described. After the diffusion bonding step is completed, in the upper surface of the etched workpieces 52 to 54 that are integrally bonded, a region other than a portion (see FIG. 3) where the electrode P13 of the semi-finished product 55 is to be formed is formed, for example, An insulating film such as a silicon film is formed. Next, the strain gauges SG1 to SG8 and the bridge pattern BP shown in FIG. 3 are formed on the insulating film (for the electrode P13 on the semi-finished product 55) by PVD such as sputtering or vacuum deposition. That is, for example, an etching processed product 52 to 54 in which an insulating film is formed on a fixing jig and integrally joined to a bell jar of a sputtering apparatus is attached, and after the inside of the bell jar is evacuated to a predetermined vacuum degree, The bonded etched workpieces 52 to 54 are heated to a predetermined temperature.

  In this state, the target is sputtered, and a thin film having a predetermined thickness is attached and formed as a resistor on the insulating film. Next, metal electrodes are sequentially formed on the thin film-formed insulating film by vacuum deposition. Thereafter, strain gauges SG1 to SG8 and electrodes P11 to P15 are attached and formed by a wet etching method. If necessary, the resistance values of the strain gauges SG1 to SG8 are adjusted by heat treatment or laser trimming. The details of the methods for forming the strain gauges SG1 to SG8 and the bridge pattern BP are disclosed in, for example, Japanese Patent Laid-Open No. 6-137804. This process is referred to as a “physical vapor deposition process”.

Next, regarding the etched workpieces 52 to 54 (hereinafter referred to as “workpieces”) in which the strain gauges SG1 to SG8 and the bridge pattern BP are formed on the upper surface of the etched workpiece 52, the wires are joined together. subjected to electric discharge machining, is narrow connecting portion having a width which is outer end of the narrow connecting portion 32c (a portion close to the annular portion 32a) 2 one wire cutting scheduled portion 56a and the workpiece 57 in the workpiece 56 By removing (cutting) the two scheduled wire cut portions 57a, an air gap AP is formed, and the outer end portion of the connecting portion 32c that connects the small disk portion 32b and the annular portion 32a, that is, the annular portion 32a. The portion close to is cut and separated, and the connecting portion between the large disc portion 33b and the annular portion 33a is cut and separated. Further, the ten strain generating bodies 14 are separated by removing (cutting) the wire cut scheduled portion 52a shown in FIG. That is, a thin wire such as brass, copper, tungsten, molybdenum, or stainless steel (usually about φ0.2 mm) is used as an electrode wire, and a machining liquid (high purity water) is supplied to the discharge site, and voltage is applied to the electrode wire and workpiece. Is applied, and a pulsed discharge is repeatedly generated in the machining fluid between the workpiece and the electrode wire while continuously running in a state where tension is applied to the electrode wire. After removing 57a to form the gap AP, notches 31ab, 32ab and 33ab shown in FIG. 6 are formed to separate the ten strain bodies 14 from the workpiece. The details of wire electric discharge machining are disclosed in, for example, Japanese Patent Laid-Open No. 9-103922. This process is referred to as a “joint part removing process”.

Next, a method for assembling the acceleration transducer will be described with reference to FIGS. First, the base 12 in which the O-ring 13 is fitted in the concave groove 12a is fitted to the inner periphery of the main body 11a constituting the casing 11. Next, after accommodating the strain generating body 14 in the base 12 via the O-ring 13, the five electrodes P11 to P15 constituting the bridge pattern BP formed on the top surface of the strain generating body 14, and the flexible substrate Fifteen corresponding five electrodes P21 to P25 are respectively connected by soldering.
Next, after placing the inner lid 16 in which the O-ring 17 is fitted in the concave groove 16 a on the upper surface of the strain generating body 14, the ring nut 19 is screwed into the female screw formed on the inner periphery near the upper end of the casing 11. Combine. Next, a cylindrical tightening jig pin (not shown) is fitted into the circular through hole 19a or 19b drilled in the ring nut 19, and the ring nut 19 is further tightened by rotating the pin. . Thereby, the strain body 14 is firmly fixed to the casing 11 by the contact portion with the base 12 and the contact portion with the inner lid 16 and is sealed by the O-rings 13 and 17. Next, silicon oil (not shown) that fills the gap AP formed in the strain body 14 and functions as a damper from the through hole 16b formed in the substantially central portion of the inner lid 16 is injected, and then the through hole 16b. The sealing rubber 18 is fitted into the. It should be noted that the damping ratio can be reduced to about 0.7 by adjusting the viscosity of the gap AP or silicon oil.

Next, after the pressing plate 20 is placed on the upper surface of the sealing rubber 18, the casing lid 21 is firmly fixed to the upper end of the casing 11 with an adhesive. Thereby, the presser plate 20 presses the sealing rubber 18, and the confidentiality of the casing 11 is maintained. On the other hand, after connecting each end of a plurality of metal wires (core wires) protruding from the tip of the cable 22 to the lands L11, L12, L21, L22, L31, L41, L42 and L51 formed on the flexible substrate 15, respectively. The outer periphery of the overhang portion 11 b and the outer periphery of the tip end portion of the cable 22 are covered with a rubber cap 23.
The acceleration transducer assembled as described above was inserted into four circular through holes 21a drilled in the four corners of the casing lid 21 by inserting four mounting screws (not shown) into the four corners of the casing 11. It is attached by being inserted into four attachment screw holes (not shown) and screwed into female screw holes formed in the object to be measured.

  As schematically shown in FIG. 15, when the acceleration is applied to the casing 11 due to the vibration, impact, etc. of the object to be measured and the casing 11 performs an acceleration motion, a weight formed by integrally joining a plurality of large disk portions 33b. Since the portion W is connected to the two upper and lower strain generating plates 31, the portion W is displaced relative to the casing 11 along the central axis of the weight portion W to form the upper strain generating plate 31. Strain is generated in the strain generating portions 31d and 31e. Therefore, the strain gauges SG1 to SG8 attached to the surfaces of the strain generating portions 31d and 31e are only strains generated by the deformation of the strain generating portions 31d and 31e by the acceleration acting along the central axis direction of the weight portion 62. Is detected without interference, and its resistance value changes, so that the acceleration received from the object to be measured can be detected with high accuracy.

  Thus, according to the above-described embodiment of the present invention, the pair of upper and lower strain generating plates 31 having the strain generating portions 31d and 31e that generate strain upon receiving acceleration are interposed between the pair of upper and lower spacer plates 32. Since the strain generating body 14 is formed by sandwiching the weight constituting portion as the weight portion W and integrating them by diffusion bonding, the size can be extremely reduced, and the strain generating body 14 can be realized. Strain gauges SG1 to SG8 are sputtered on the strain generating portions 31d and 31e, respectively, and a Wheatstone bridge circuit is configured with eight strain gauges SG1 to SG8 in the vicinity of the strain generating portions 31d and 31e of the strain generating body 14. Therefore, a bridge pattern BP having power supply electrodes P11 and P14, output electrodes P12 and P15, and a ground electrode P13 is formed.

  Therefore, as shown schematically in FIG. 15, the acceleration converter according to this embodiment has a weight portion W that is equal to the weight W even if acceleration in the vertical direction is applied due to vibration, impact, etc. of the object to be measured. The upper and lower strain-generating plates 31 and the lower strain-generating plate 31 almost suppress the swinging in the left-right direction. For this reason, the strain generating portions 31d and 31e of the upper strain generating plate 31 include a small compressive strain based on the lateral movement of the weight portion 62 in addition to a compressive strain or a tensile strain based on the vertical motion of the weight portion 62. Although it cannot be said that there is no possibility of tensile strain, it is very slight. Therefore, the values output from the strain gauges SG1 to SG8 are values based on the strain corresponding to the vertical acceleration to be detected by most, and interference can be effectively suppressed. As a result, as in the conventional acceleration transducer, the strain gauge is attached on the strain generating portions 31d and 31e of the lower strain generating plate 31, and is attached on the strain generating portions 31d and 31e of the upper strain generating plate 31. Data with high reliability without electrical processing of resistance value changes obtained from the strain gauges and the strain gauges attached to the strain-generating portions 31d and 31e of the lower strain-generating plate 31 Is obtained. If the strain gauges are attached to the strain generating portions 31d and 31e of the upper and lower strain generating plates 31, and the resistance value change obtained from each strain gauge is electrically processed, the reliability is further improved. Of course, data can be obtained. Therefore, a bridge circuit as shown in FIG. 3 can be configured in one plane (in this case, the upper surface), wiring processing is easy, and cost reduction can be realized.

In the acceleration converter according to this embodiment, the vibration mode of the weight portion W is dominated by the vibration mode in the vertical direction, which is the sensitivity direction. The characteristics can be obtained and the light weight part W and the ultra-thin deformed part T can be combined to expand the frequency response range.
In addition, according to the above-described embodiment of the present invention, after the etched workpieces 52 to 54 for the strain generating plate 31, the spacer plate 32, and the weight plate 33 are manufactured by etching, the etched workpieces 52 to 54 are integrated by diffusion bonding, and strain gauges SG1 to SG8 and a bridge pattern BP are formed by physical vapor deposition on the upper surfaces of the etched workpieces 52 to 54 that are integrally bonded. Accordingly, the weight portion 62 having a minute mass (for example, about 0.1 g) is vertically moved by the strain plate 31 having a thickness (about 0.1 mm) that is difficult to manufacture by conventional machining (limit of about 0.2 mm). The strain body 14 having an integrated structure to be sandwiched can be manufactured.

  That is, the acceleration transducer can be easily downsized. As an example, in the conventional acceleration transducer, the vertical dimension is about 16 mm, the horizontal dimension is about 16 mm, and the thickness dimension is about 16 mm. However, in the acceleration transducer of this embodiment, the vertical dimension is about 10 mm. The lateral dimension can be about 10 mm and the thickness dimension can be about 5 mm. Further, since the etching process, the diffusion bonding process, and the physical vapor deposition process can all be batch-processed, it can be manufactured at a low cost. Furthermore, since parts are manufactured by etching with a high degree of freedom in processing shape, acceleration converters having a low capacity to a large capacity (for example, 1G to 100G) can be manufactured. In this case, since the gap AP can be finely adjusted, a desired damping ratio can be obtained. In addition, when oil damping is performed with silicon oil, there is little variation in the distance between the viscous friction surfaces, and stable damping characteristics can be obtained. As an application of this acceleration converter, for example, it can be attached to a location of an object to be measured that has not been able to be measured, for example, a narrow space location, such as an automobile crash test, steering stability test, vibration measurement, and the like.

  Further, according to the above-described embodiment of the present invention, as shown in FIG. 1, the acceleration converter has the base 12 fitted to the inner periphery of the main body 11 a of the casing 11, and the base 12 has the O After accommodating the strain generating body 14 via the ring 13, the inner lid 16 fitted with the O-ring 17 in a state where the flexible substrate 15 is sandwiched between the upper surface of the strain generating body 14 and the inner lid 16 is used as the ring. The nut 19 is tightened and pressed, pressed by the sealing rubber 18, the pressing plate 20, and the case-singing lid 21, and the casing lid 21 is sealed with an adhesive, so that the periphery of the strain body 14 is tightly sealed. On the other hand, after connecting each end of a plurality of metal wires (core wires) protruding from the tip of the cable 22 to the lands L11, L12, L21, L22, L31, L41, L42 and L51 formed on the flexible substrate 15, respectively. The outer periphery of the overhang 11b and the outer periphery of the tip of the cable 22 are covered with a rubber cap 23. Therefore, unlike the conventional acceleration converter, a complicated, bulky, and expensive cable gland and an airtight terminal are unnecessary, so that the acceleration converter can be downsized and reduced in cost.

The embodiment has been described in detail with reference to the drawings. However, the specific configuration is not limited to the embodiment, and various modifications may be made without departing from the scope of the invention. Of course you can.
For example, in the above-described embodiment, the example in which the present invention is applied to the acceleration converter accommodated in the casing 11 is shown, but the present invention is not limited to this. That is, a material obtained by physically depositing strain gauges SG1 to SG8 and the bridge pattern BP on either one or both of the upper surface and the lower surface of the strain generating body 14 may be used alone. In this case, in order to prevent deterioration of the strain gauge, it is desirable to use the surface of the strain gauge and the bridge pattern BP with a coating such as an antioxidant film.
In addition, when the present invention is applied to a pressure transducer, a peripheral portion of a diaphragm made of a metal such as a thin stainless steel is etched by diffusion bonding with a main body (rigid body) of the pressure transducer. After the integration, a strain gauge and a bridge pattern BP may be attached to the surface of the diaphragm by sputtering. When the present invention is applied to a load transducer, a force transmission rod is formed with the weight portion W of the acceleration transducer shown in FIG. 1 as a small diameter, and a cylindrical load is introduced into the central portion of the upper deformation portion T. The thin plates may be sequentially overlapped and integrated by diffusion bonding so as to further add a portion.

Further, after the peripheral portions of the two diaphragms and the main body of the load transducer are integrated by diffusion bonding, a strain gauge and a bridge pattern BP are manufactured by physical vapor deposition on the surface of the diaphragm. By producing the pressure transducer and the load transducer in this way, the generation of thermal strain can be reduced compared to the case where the tire frame is fixed to the main body of the pressure transducer or the main body of the load transducer by welding. Therefore, the initial strain can be reduced.
Moreover, although the example which forms eight strain gauges SG1-SG8 in the surface of the cross beam 31 was shown in embodiment mentioned above, it is not limited to this, Four strain gauges SG8, SG1, SG5 shown in FIG. And SG4 or only four strain gauges SG3, SG2, SG6 and SG7 may be formed.
In the above-described embodiment, the strain generating body 14 is made of a metal such as stainless steel. However, the present invention is not limited to this. For example, the elastic body has a wide elastic limit, high strength, good rust prevention, and etching. Any material can be used as long as it is suitable for use as a strain generating body, such as easy to process, and can be diffusion bonded. Examples of such a material include beryllium (Be) and copper (Cu).

In the above-described embodiment, the strain generating body 14 shows an example in which the etching processed products 52 to 54 for the strain generating plate 31, the spacer plate 32, and the weight plate 33 are integrated by diffusion bonding. However, the present invention is not limited to this, and brazing or electron beam welding may be used, or the annular portions 31a, 32a and 33a may be laser welded together.
Further, the present invention can be applied not only to a small physical quantity / electric quantity converter but also to a large physical quantity / electric quantity converter. The advantages obtained can be obtained as they are. Further, a large physical quantity / electric quantity converter is not limited to a sputter gauge.
In the present invention, the strain plate, the weight plate, and the spacer plate are integrated by diffusion bonding. However, in addition to diffusion bonding, brazing, electron beam welding is used as an integration bonding means. Either laser welding or spot welding can be used. However, integration by diffusion bonding is excellent in that it can be manufactured at low cost with high accuracy, small initial strain, good yield.

Moreover, although this invention illustrated about the etching process in the manufacturing process of the said strain generating board, a spacer board, and a weight board, for example, in addition to an etching process, any of laser processing and machining are also possible. Here, the machining includes cutting and polishing.
However, the strain-generating plate, the weight plate, and the spacer plate obtained by the etching process can form a very thin strain gauge and can also greatly increase the gauge factor.
Moreover, the said connection part removal process is good also by any of laser processing and machining other than wire electrical discharge machining. In the case of wire discharge, the cutting and separation can be easily and beautifully performed.
Moreover, it is desirable to fill a void around the strain generating body with a viscous fluid such as silicon oil or an inert gas .

It is an expanded sectional view showing the appearance composition of the acceleration converter concerning a 1st embodiment of the present invention. It is a top view of the acceleration converter shown in FIG. It is a top view which shows the external appearance structure of the strain gauges SG1-SG8 and bridge | bridging pattern BP which were formed in the upper surface of the strain body which comprises the acceleration converter of FIG. It is a circuit diagram which shows the circuit structure of the Wheatstone bridge circuit comprised by the strain gauges SG1-SG8 and bridge pattern BP shown in FIG. It is a top view which shows the external appearance structure of the flexible substrate connected with the electrodes P11-P15 which comprise the bridge pattern BP shown in FIG. FIG. 2 is an enlarged plan view of a strain generating body constituting the acceleration converter shown in FIG. 1. It is an expanded sectional view of the strain body shown in FIG. It is a disassembled perspective view of the strain body shown in FIG. (A)-(d) of this figure is a manufacturing-process figure of the strain generating board which comprises the strain generating body shown in FIG. (A), (b) of this figure is a manufacturing-process figure of the strain generating board which comprises the strain generating body of FIG. It is a top view which shows the structure of the etching processed material in which many strain generating plates were formed in FIG. (A) And (b) of this figure is the top view and front view for demonstrating the manufacturing method of the strain body shown in FIG. It is a perspective view for demonstrating the manufacturing method of the strain body shown in FIG. It is a conceptual diagram for demonstrating the method of carrying out the diffusion bonding of each etching processed material about a strain generating board, a spacer, and an intermediate part. It is a figure which shows the typical structure of the acceleration converter shown in FIG. It is a figure which shows an example of the typical structure of the conventional acceleration converter, and the shaking of the weight part which comprises this acceleration converter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Casing 11a Main-body part 11b Overhang | projection part 11ba Opening part 12 Base 12a, 16a Groove | groove 13, 17 O ring 14 Strain body 15 Flexible board 16 Inner lid 16b Through-hole 18 Sealing rubber 19 Ring nut 19a, 19b, 21a Circular Through hole 20 Presser plate 21 Casing lid 22 Cable 23 Rubber cap 31 Strain plate 31a, 32a, 33a Ring part 31ab, 32ab, 33ab Notch part 31b, 32b Small disk part 33b Large disk part 31c Beam part 31d, 31e Portion 32 Spacer plates 32c, 33c Connection portion 33 Weight plate 41 Thin plate 41a Front surface 41b Back surface 42 Liquid tank 43 Pickling solutions 44a, 44b Photoresist films 45a, 45b Exposure masks 46a, 46b Ultraviolet lamps 47a, 47b Photoresist pattern 48 Etching solution 49 spray Nozzle 50 Intermediate workpiece 51 Stripping solution 52-54 Etched workpieces 52a, 56a, 57a Wire cut scheduled portion 52b Through hole 55-57 Semi-finished product 61 Vacuum furnace W Weight portion T Deformed portion AP Space S Spacer portion BP Bridge pattern BV Bridge voltage CP1 to CP5 Copper foil pattern eo Output voltage L11, L12, L21, L22, L31, L41, L42, L51 Lands P11 to P15, P21 to P25 Electrodes SG1 to SG8 Strain gauge

Claims (6)

A pair of strain-generating plates made of a thin metal plate and having a strain-generating portion that receives a physical quantity and generates strain;
A plurality of weight plates made of a thin metal plate and constituting a weight portion supported by the strain plate by being integrated,
It consists of a thin plate of metal, and consists of a spacer plate inserted between the pair of strain-generating plates and the weight plate,
The two strain generating plates, the two spacer plates, and the plurality of weight plates are integrated in a stacked state so that the acceleration applied to the strain generating body can be detected. A strain generating body,
A plurality of strain gauges attached to the strain-generating portion of the strain-generating body;
A power supply electrode formed in the vicinity of the strain-generating portion of the strain-generating body, connected to each of the plurality of strain gauges to constitute a Wheatstone bridge circuit, and for supplying a bridge voltage to the Wheatstone bridge circuit, and the Wheatstone A bridge pattern having an output electrode for extracting an output voltage from the bridge circuit;
A substrate on which a plurality of electrodes connected to the power supply electrode and the output electrode constituting the bridge pattern and a pattern for connecting the plurality of electrodes and a plurality of metal wires constituting a cable are formed, respectively. ,
A one-end opening type casing in which a female screw is formed on the inner periphery in the vicinity of the opening;
A base fitted into the inner periphery of the casing and having a first O-ring fitted in a groove formed in the inner bottom surface;
An inner lid in which a second O-ring is fitted in a concave groove formed on the lower surface;
A ring nut screwed into the female screw of the casing;
A casing lid,
The plurality of strain gauges and the bridge pattern are formed in the base, and the strain body in which the substrate is connected to the bridge pattern is accommodated, and the inner lid is formed on the strain body and the substrate. The strain nut is fixed in the casing by screwing the ring nut into the female screw of the casing, and the strain body is cut off from the outside by fixing the casing lid. A physical quantity / electric quantity converter characterized by being sealed.   The strain body is formed such that the weight portion is formed in the central portion with a gap between the periphery and the fixed portion, and the void of the strain body is filled with a viscous fluid. The physical quantity / electric quantity converter according to claim 1. With a thin metal plate, an annular part is arranged on the outer peripheral side, a small disk part is arranged in the center part, and four beams narrower than the diameter of the small disk part between the annular part and the small disk part A strain plate in which the portions are arranged in a cross shape, and a strain generating portion that receives a physical quantity at the inner end and the outer end of each beam portion and generates strain is integrally formed;
A large disk part that constitutes a weight part supported by the strain-generating plate by being integrated with a thin metal plate is disposed in the center, and an annular part on the outer peripheral side of the large disk part A narrow connecting portion is disposed at an angular position between the annular portion and the large disc portion so as not to overlap the cross-shaped beam portion of the strain plate. A plurality of integrally formed weight plates;
With a thin metal plate, a small disk portion as a space holding portion for holding the space between the strain generating plate and the weight portion is disposed on the center side, and an annular portion is disposed on the outer peripheral side, Spacers formed between the annular portion and the small disc portion, each having a narrow connecting portion at an angular position that does not overlap with the cross-shaped beam portion of the strain plate, and are integrally formed. Processing steps to produce each plate,
A joining step in which the strain plates are respectively arranged on both end sides of the plurality of weight plates via the spacer plates and integrated with each other;
Of the connecting portion between the large disc portion and the annular portion of the weight plate and the connecting portion between the small disc portion and the annular portion of the spacer plate, portions close to the annular portion are respectively removed. And a connecting part removing step .   The manufacturing method of the strain body according to claim 3, wherein the processing step is manufactured by any one of etching processing, laser processing, and machining.   The method for producing a strain generating body according to claim 3, wherein the joining step uses any one of diffusion joining, brazing, electron beam welding, and laser welding. The method for manufacturing a strain generating body according to claim 3, wherein the connecting portion removing step uses any one of wire electric discharge machining, laser machining, and machining.

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