JP5221844B2 - Manufacturing method of pressure transducer - Google Patents

Description

The present invention, the pressure-receiving surface and a method of manufacturing the standing distortion diaphragm that converts into an electric signal by using a strain gauge provided on the back pressure transducer deformation of the strain the diaphragm in response to the pressure difference between the the back.

A conventional pressure transducer is configured to convert deformation of a strain-generating diaphragm due to a pressure difference between a pressure-receiving surface and its back surface into an electrical signal using a strain gauge attached to the back surface of the strain-generating diaphragm. Depending on the back pressure type of strain diaphragm,
(A) an open-air type in which a back pressure chamber covering the back surface of the strain-generating diaphragm is opened to the atmosphere;
(B) an air-sealed type that seals in a state where the back pressure chamber covering the back space of the strain-generating diaphragm is filled with air;
(C) an inert gas sealing type in which an inert gas is filled and sealed in a back pressure chamber covering the back space of the strain-generating diaphragm;
(D) There is a vacuum-sealed type in which the back pressure chamber covering the back space of the strain-generating diaphragm is evacuated and sealed.

  FIG. 6 is a cross-sectional view showing a configuration example of a conventional pressure transducer of an inert gas sealing type among the back pressure types of the above-described four strain generating diaphragms. The pressure introducing portion 1 is made of a metal such as stainless steel and has a coupling portion 1a composed of a male screw coupled to a portion to be measured such as a gas insulated switchgear (not shown). A pressure introduction path 2 for introducing the fluid pressure to be measured is formed through the central shaft portion of the pressure introduction portion 1. A cylindrical portion 3a having rigidity integrated with a strain-generating diaphragm 3 made of a metal such as stainless steel is airtightly fixed to an end portion of the pressure introducing portion 1 opposite to the coupling portion 1a by welding or the like. A pressure receiving chamber 4 in which a fluid to be measured introduced through the pressure introduction path 2 is stored is formed between the inner surface of 3 and the end face of the pressure introduction portion 1. On the back side opposite to the pressure receiving surface of the strain generating diaphragm 3 forming a part of the pressure receiving chamber 4, there is a strain gauge 5 for converting the deformation of the strain generating diaphragm 3 due to the pressure difference between the pressure receiving surface and the back surface into an electric signal. It is attached by adhesion, vapor deposition, sputtering, welding, or other means.

Cylindrical members 7 are arranged concentrically so as to cover the outer periphery of the strain generating diaphragm 3 with a constant interval. One end edge of the cylindrical member 7 is airtightly fixed to the pressure introducing portion 1 by welding or the like, and an airtight terminal 8 is fitted into the other end opening. The peripheral edge of the metal lid member 8a constituting the hermetic terminal 8 is hermetically fixed to the cylindrical member 7 by welding or the like. The cylindrical member 7 and the airtight terminal 8 form a reference pressure chamber 9 on the back side of the strain generating diaphragm 3. In addition, a plurality of pin terminals 10 are penetrated and supported by an insulating sealing material 11 such as glass in the plurality of holes 8b formed in the lid member 8a. Each other end of the gauge lead 6 is connected. Further, the exhaust pipe 12 is fixed to the airtight terminal 8 in an airtight manner by welding or the like.
When sealing the reference pressure chamber 9, for example, in a vacuum chamber of 10 mmHg or less, the pressure converter is heated to a temperature of 120 ° C. to 140 ° C., and the reference pressure chamber is passed through the hollow exhaust pipe 12. A vacuum baking process is performed for about 40 to 50 hours in a state where the vacuum chamber 9 and the vacuum chamber are in communication with each other, and this adheres to the inner wall surface of the reference pressure chamber 9 and the surface of the strain generating diaphragm 3 that cause outgassing. After depositing and organic matter (for example, adhesive, coating agent, soldering part flux, etc.) present in the reference pressure chamber 9 is gasified and discharged out of the reference pressure chamber 9, dry nitrogen, argon gas, etc. An appropriate amount of active gas is injected from the exhaust pipe 12.

Next, the intermediate portion 12b of the outward projecting portion of the exhaust pipe 12, which is essentially a tubular shape, is crushed and sealed from the outer peripheral side, and then a molten solder (not shown) is filled into the tip opening 12a of the exhaust pipe 12. The exhaust pipe 12 is completely sealed. The exhaust pipe 12 is thus crushed to prevent solder flux from flowing into the reference pressure chamber 9 through the exhaust pipe 12 when the tip opening 12a of the exhaust pipe 12 is solder-sealed. The above-described conventional technique is disclosed in, for example, Patent Document 1 (Japanese Patent Laid-Open No. 8-202201). Hereinafter, this technique is referred to as a first conventional example.
Next, FIG. 7 is a cross-sectional view showing another configuration example of a vacuum-sealed conventional pressure transducer. The pressure introducing portion 21 is made of a metal such as stainless steel and has a coupling portion 21a composed of a male screw coupled to a portion to be measured such as a gas insulated switchgear (not shown). A pressure introduction path 22 through which the fluid pressure to be measured is introduced is formed through the central shaft portion of the pressure introduction portion 21. A cylindrical portion 23a having rigidity integrated with a strain-generating diaphragm 23 made of a metal such as stainless steel is airtightly fixed to the end portion of the pressure introducing portion 21 opposite to the coupling portion 21a by welding or the like. A pressure receiving chamber 24 in which a fluid to be measured introduced through the pressure introduction path 22 is stored is formed between the inner surface of 23 and the end face of the pressure introduction portion 21.

On the back side opposite to the pressure receiving surface of the strain generating diaphragm 23 forming a part of the pressure receiving chamber 24, there is a strain gauge 25 for converting the deformation of the strain generating diaphragm 23 due to the pressure difference between the pressure receiving surface and the back surface into an electric signal. It is attached by adhesion, vapor deposition, sputtering, welding, or other means. Both ends of the gauge resistor are integrally connected to two gauge tabs (not shown). And although not shown in figure, the gold | metal layer with favorable solderability is formed in the surface of each gauge tab by sputtering, vapor deposition, etc. One end of each of the two gauge leads 26 made of gold or the like is connected to the gold layer by solder.
Cylindrical portions 27a of the airtight terminals 27 are concentrically arranged so as to cover the outer periphery of the strain generating diaphragm 23 at a predetermined interval. The hermetic terminal 27 is made of an alloy (for example, Kovar (trade name)) made of nickel, cobalt, and iron. As shown in FIG. 8, the cylindrical portion 27a and the cylindrical portion 27a at one end edge of the cylindrical portion 27a The airtight terminal 27 forms a first vacuum chamber 28 on the back side of the strain generating diaphragm 23. This is shown as A in FIG. The outer edge of the other end of the cylindrical portion 27a is formed with a substantially V-shaped groove 27aa as shown in an enlarged view in FIG. 9A, and its tip is scraped off. 21 is hermetically fixed by welding or the like.

In addition, as shown in FIG. 8, a substantially L-shaped pin terminal 29 is penetrated and supported by an insulating sealing material 30 such as glass in the two holes 27ba formed in the terminal mounting portion 27b. Each other end of the gauge lead 26 is connected to the pin terminal 29. The outer edge of the cylindrical rising portion 27bb shown as B in FIG. 8 formed on the back surface side of the terminal mounting portion 27b is a cylindrical extending portion formed in a taper shape as shown in FIG. 9B. The inner edge of 27bb and the machining surface 27bc are cut so as to form an acute angle, and the end of the cylindrical extension 27bb is cut off.
Further, in FIG. 8, a sealing fitting 31 made of a metal such as stainless steel is fitted to the inner edge of the cylindrical extension portion 27bb and then hermetically fixed by welding or the like. As shown in FIG. 10B, the sealing fitting 31 is configured by integrally forming a disk portion 31a, an outer cylindrical portion 31b, and an inner cylindrical portion 31c. A communication hole 31aa that communicates with the inner cylindrical portion 31c is formed at the center of the disk portion 31a.

  Further, the inner edge of one end of the outer cylindrical portion 31b shown as C in FIG. 10B is cut so that the inner edge of one end of the outer cylindrical portion 31b and the machining surface 31ba form an acute angle as shown in an enlarged view in FIG. And the tip is scraped off. As described above, the outer edge of the cylindrical extension 27bb of the terminal mounting portion 27b shown as B in FIG. 8 is processed to be enlarged as shown in FIG. 9B, and as C in FIG. 10B. Since the inner edge of one end of the outer cylindrical portion 31b shown in FIG. 11 is processed to be enlarged and shown in FIG. 11, welding is performed after the sealing metal fitting 31 is fitted to the inner edge of the cylindrical extension portion 27bb of the terminal mounting portion 27b. Airtightness can be ensured by fixing by, for example. On the other hand, as shown in FIG. 10A, a vapor deposition preventing plate 32 made of a metal such as stainless steel is fixed to the inner surface of the disk portion 31a of the sealing fitting 31 by spot welding or the like. The vapor deposition prevention plate 32 is for protecting important parts such as the strain gauge 25 from the welding gas or the like when the first welding sealing is performed on the tip of the inner cylindrical portion 31c of the sealing fitting 31.

  In FIG. 7, cylindrical terminal pipes 33 are concentrically arranged so as to cover the outer periphery of the airtight terminal 27 at a predetermined interval. The terminal pipe 33 is made of, for example, a metal such as stainless steel, and the outer edges of both ends thereof are indicated by A in FIG. 12 and enlarged in FIG. The tip is scraped off. One end outer edge of the terminal pipe 33 is airtightly fixed to the pressure introducing portion 21 by welding or the like in FIG. Further, a circular hole 33b is formed at a position away from one end of the terminal pipe 33, and after the tip end 34a of the welding rod (sealing rod) 34 shown in FIG. A second weld seal is made. The circular hole 33b is formed at a position away from a wiring terminal 37 attached to an airtight terminal 35 fitted to the other end opening of the terminal pipe 33, which will be described later. Further, an airtight terminal 35 is fitted into the other end opening of the terminal pipe 33. The peripheral edge of the airtight terminal 35 is airtightly fixed to the opening of the other end of the terminal pipe 33 by welding or the like. The terminal pipe 33 and another hermetic terminal 35 form a second vacuum chamber 36 on the back side of the sealing fitting 31. In addition, the wiring terminals 37 are penetrated and supported by holes 35a formed in the airtight terminals 35 by an insulating sealing material 38 such as glass. It is connected.

Further, a cylindrical case 40 is concentrically arranged so as to cover the outer periphery of the terminal pipe 33 at a predetermined interval. The case 40 is made of, for example, a metal such as stainless steel, and an outer edge of one end thereof is airtightly fixed to the pressure introducing portion 21 by welding or the like. On the other hand, a cord holder 42 that penetrates and holds the cord 41 is fitted into the other end opening of the case 40. Each one end of the conducting wire 43 constituting the cord 41 is connected to the corresponding wiring terminal 37 by soldering.
Next, a method for assembling the pressure transducer having the above configuration will be described with reference to FIGS. 15 and 16.
(1) First, the strain-generating diaphragm 23 in which the strain gauge 25 is formed, the pressure introducing portion 21, and the airtight terminal 27 having the cylindrical portion 27a are assembled in advance by welding or the like.
(2) Next, from the opening of the cylindrical extension portion 27bb of the terminal mounting portion 27b constituting the hermetic terminal 27, the gauge tab (not shown) of the strain gauge 25 and the hole 27ba formed in the terminal mounting portion 27b are insulated. A pin lead 29 that is supported by penetration by the sealing material 30 is connected by a gauge lead 26.

(3) Next, after fitting the sealing fitting 31 to which the vapor deposition prevention plate 32 is fixed to the inner edge of the cylindrical extension 27bb of the terminal mounting portion 27b constituting the airtight terminal 27, the cylindrical extension 27bb Are fixed to each other by welding or the like.
(4) Then, using the first beam sealing device shown in FIG. 15, the first welding sealing is performed on the tip of the inner cylindrical portion 31 c of the sealing fitting 31. In the first beam sealing device shown in FIG. 15, a mounting base 55 bent at a predetermined angle on a substantially rectangular support plate 51 is bolted 57 via a substantially rectangular spacer 56 at predetermined intervals. It is attached using. Each mounting base 55 is attached with a bolt 54 using a receiving jig 53 into which the assembling product 52 that has undergone the steps (1) to (3) described above is inserted. In FIG. 15, the assembling product 52 is attached to the receiving jig 53 only on the center mounting base 55. The first beam sealing device is placed in a chamber (not shown) kept in a vacuum. After inserting the pressure introducing part 21 of the intermediate product 52 into the receiving jig 53, the intermediate product 52 is protected in order to protect the portion other than the tip of the inner cylindrical portion 31c of the sealing metal fitting 31 constituting the intermediate product 52. A cover 58 is attached. Next, by driving an electron beam welding apparatus (not shown) and irradiating the tip of the inner cylindrical portion 31c of the sealing metal fitting 31 with the electron beam emitted from the electron gun as indicated by an arrow in the figure, the inner cylindrical portion 31c. The first vacuum chamber 28 is formed between the airtight terminal 27 and the back surface of the strain-generating diaphragm 23.

(5) Next, one end outer edge of the terminal pipe 33 is fixed by welding or the like to the pressure introducing portion 21 of the product in the process of assembly (1) to (4).
(6) Next, each end of the wiring terminal 37 supported by an insulating sealing material 38 such as glass in the hole 35a formed in the airtight terminal 35 and the above-described steps (1) to (5). One end of each pin terminal 29 in the middle of assembly is connected by a lead wire 39.
(7) Next, the peripheral edge of the airtight terminal 35 is fixed to the other end opening of the terminal pipe 33 of the intermediate product that has undergone the steps (1) to (6) described above by welding or the like.
(8) And after fitting the front-end | tip part 34a (refer FIG. 14) of the welding rod (sealing rod) 34 to the circular hole 33b of the terminal pipe 33, using the 2nd beam sealing instrument shown in FIG. A second weld seal is formed. The second beam sealing device shown in FIG. 16 is placed on a table 61 installed in a chamber kept in a vacuum, and is an assembled product that has undergone the above-described steps (1) to (7). It comprises a holding jig 62 that holds the pressure introducing portion 21 up and down and holds the above-mentioned assembled product horizontally, a leaf spring 63, and a screw 64. The holding jig 62 includes a lower holding portion 62a and an upper holding portion 62b. A plate spring 63 for urging the above-mentioned assembled product downward is attached by screws 64 from the side surface to the lower surface of the upper holding portion 62b. Yes.
As shown in FIG. 16, in the state where the above-mentioned assembled product is held, an electron beam welding apparatus (not shown) is driven to irradiate the welding rod 34 with an electron beam emitted from an electron gun as indicated by an arrow in the figure. Thus, the welding rod 34 is welded and sealed, and a second vacuum chamber 36 is formed between the terminal pipe 33, the airtight terminal 27, and the airtight terminal 35. Hereinafter, this technique is referred to as a second conventional example.
JP-A-8-202201

In the first conventional example described in Patent Document 1 described above, since the organic substance gasified through the exhaust pipe 12 is discharged or an inert gas is injected, the exhaust pipe 12 is other than the airtight terminal 8. There is a problem in that it cannot be attached, has a positional limitation in structure, and has a low degree of freedom in design. In order to reduce the pressure transducer, the exhaust pipe 12 also needs to be reduced in size. However, when the exhaust pipe 12 is reduced in size, it becomes difficult to fill the exhaust pipe 12 with a small diameter with molten solder, If this filling is incomplete, there is a problem that the inert gas may leak.
On the other hand, in the above-described second conventional example, when the sealing metal fitting 31 is easily welded or when the first welding sealing is performed on the tip of the inner cylindrical portion 31c of the sealing metal fitting 31, the sputter or welding gas is used. In order to protect important parts such as the strain gauge 25, there has been a problem that the vapor deposition prevention plate 32 must be provided. In the second conventional example described above, the circular hole 33b of the terminal pipe 33 where the second welding sealing is performed must be provided at a position away from the wiring terminal 37 in order to form the second vacuum chamber 36. In addition, there is still a problem that there is a positional restriction in terms of structure, and the degree of freedom in design is small.

  Therefore, according to the first and second conventional examples described above, many parts are required only for vacuum sealing, and a strain gauge 25 such as a welding process for vacuum sealing or a vapor deposition prevention plate 32 is used. There is a problem that an assembling process of protective parts is necessary to protect important parts such as these. Further, according to the first and second conventional examples described above, there is a problem that the structure and dimensions of the pressure transducer are limited, and the degree of freedom in design is small. As a result, there are problems that the price of the completed pressure transducer is high and that it is difficult to assemble.

The present invention has been made in view of the above circumstances, an object of claim 1 in its, in particular, only opening for only parts and openings, the vacuum seal for exhausting gas from the vacuum chamber It is possible to reduce the number of parts or only for protecting important parts, thereby enabling the reduction of the manufacturing process and mounting process of each of the above parts and the sealing process of each of the above parts, and the structure. It is possible to improve the design freedom in terms of upper and dimensions, reduce costs, enable vacuum sealing with a simple method, facilitate assembly, improve reliability, and easily An object of the present invention is to provide a method of manufacturing a pressure transducer that can be miniaturized.
The object of claim 2 of the present invention is to exhaust gas reliably from the vacuum chamber, in particular, without providing parts or openings for exhausting the gas from the vacuum chamber, or openings only for vacuum sealing. An object of the present invention is to provide a method of manufacturing a pressure transducer that can be used.
The object of the third aspect of the present invention is to provide a method of manufacturing a pressure transducer that makes it possible to appropriately adjust the degree of vacuum in a vacuum chamber.

In order to achieve the above-described object, the pressure transducer manufacturing method according to the invention described in claim 1
A pressure transducer that converts a deformation of a diaphragm due to a pressure difference between a pressure receiving surface and a back surface thereof into an electrical signal using a strain gauge attached to the back surface of the diaphragm,
An airtight terminal is fitted into the second hollow portion of the body having first and second hollow portions having different diameters therein and at least one end opened, and the second hollow portion of the body is fitted. An airtight terminal adhering step for adhering airtightly to the part,
The rigid body portion of the diaphragm having a rigid body portion and a flange portion is fitted to the first hollow portion from the opening portion of the body with a small gap, and the flange portion is fitted to the opening portion of the body. A diaphragm mounting step for contacting with
Under vacuum conditions, the opening of the body and the flange of the diaphragm are sealed by welding or brazing, and the back surface of the diaphragm, the first hollow portion of the body, and the inner surface of the hermetic terminal A diaphragm fixing step for forming a vacuum chamber in a region surrounded by
It is characterized by assembling.

A pressure transducer according to the invention described in claim 2 is a method of manufacturing the pressure transducer of claim 1 ,
In the diaphragm fixing step, the vacuum chamber is vacuum-baked by evacuating the vacuum chamber from the abutment surface of the diaphragm and the body while heating the intermediate product after the diaphragm mounting step at a predetermined temperature. It is characterized by having a vacuum baking process for discharging outgas and moisture released from organic matter and deposits in the room.
The method for manufacturing a pressure transducer according to the invention described in claim 3 is the method for manufacturing the pressure transducer according to claim 2 ,
The diaphragm adhering step is a process of taking out the assembled product that has undergone the vacuum baking step to a predetermined temperature in a vacuum, and then taking it out to the atmosphere.
A vacuum in which the vacuum chamber is formed by performing a predetermined vacuum state again before cooling the assembled product that has undergone the removal step to room temperature, holding the vacuum state for a predetermined time, and then sealing by welding or brazing. And a chamber forming process.

  In addition, since there are few places to be welded, there is less risk of gas leakage due to work defects and the like, thereby improving reliability. Further, the microscopic gap between the butted surfaces of the strain-generating diaphragm and the hollow portion of the body serves as an opening for discharging a gas composed of air, organic matter, or the like when evacuating. Since this microscopic gap is smaller than the opening of the inner cylindrical portion constituting the sealing metal fitting of the second conventional example described above, the amount of welding gas entering the vacuum chamber during welding sealing is reduced, and the vacuum The degree of vacuum of the chamber can be increased as compared with the conventional case, and the amount of metal deposited on the internal part by the welding gas is reduced, so that failures caused by the metal deposited on the internal part can be reduced. In addition, the gap in the spigot part in which the strain-generating diaphragm is inserted into the hollow part of the body plays a role of protecting important parts such as a strain gauge from spatter and welding gas. Therefore, unlike the second conventional example described above, there is no need to provide a vapor deposition prevention plate only for protecting important parts such as strain gauges from spatter and welding gas, and the number of parts can be reduced accordingly. Moreover, the process of assembling a vapor deposition prevention board and the process of welding a vapor deposition prevention board to a sealing metal fitting can also be reduced.

According to the pressure transducer manufacturing method of the first aspect of the present invention, the pressure conversion for converting the deformation of the diaphragm due to the pressure difference between the pressure receiving surface and the back surface thereof into an electrical signal using the strain gauge attached to the back surface of the diaphragm. A method for manufacturing a container, comprising first and second hollow portions having different diameters therein, and being fitted into the second hollow portion of the body having at least one end opened, An airtight terminal adhering step for adhering airtightly to the second hollow portion, and the rigid body portion of the diaphragm having a rigid body portion and a flange portion are provided with a minute gap from the opening of the body to the first hollow portion. And a diaphragm mounting step for bringing the flange portion into contact with the opening portion of the body, and the opening portion of the body and the flange portion of the diaphragm under vacuum conditions. A diaphragm fixing step of forming a vacuum chamber in a region surrounded by the back surface of the diaphragm, the first hollow portion of the body and the inner surface of the airtight terminal, by welding or brazing, By assembling, it is possible to reduce the number of parts and openings only for discharging gas from the vacuum chamber, openings for vacuum sealing, or parts only for protecting important parts. This makes it possible to reduce the manufacturing process and mounting process for each of the above parts, and the sealing process for each of the above parts, as well as increase the degree of design freedom in terms of structure and dimensions, thereby reducing costs. Thus, vacuum sealing by a simple method is possible, assembly is easy and reliability can be improved, and an easy miniaturization is possible.

According to the pressure transducer manufacturing method of the second aspect of the present invention, in the pressure transducer manufacturing method according to the first aspect , the diaphragm fixing step may be performed such that an intermediate product that has undergone the diaphragm mounting step is subjected to a predetermined temperature. A vacuum baking process for discharging outgas and moisture released from organic substances and deposits in the vacuum chamber by evacuating the vacuum chamber from the abutment surface of the diaphragm and the body while heating at a vacuum. By having a vacuum baking process for discharging outgas and moisture released from organic substances and deposits in the vacuum chamber, parts and openings for discharging gas from the vacuum chamber, and vacuum sealing are provided. This makes it possible to discharge the gas from the vacuum chamber without providing an opening only for this purpose.
According to the method for manufacturing a pressure transducer of claim 3 of the present invention, the method for manufacturing the pressure transducer according to claim 2 , wherein the diaphragm fixing step is a step of assembling the product after the vacuum baking step. After cooling to a predetermined temperature in a vacuum, taking out to the atmosphere, and after the assembly process that has undergone the taking out step is again set to a predetermined vacuum state before cooling to room temperature, and holding the vacuum state for a predetermined time And a vacuum chamber forming treatment step of forming the vacuum chamber by performing sealing by welding or brazing, so that the surface roughness of the cylindrical portion of the strain-generating diaphragm and the surface roughness of the hollow portion of the body or vacuum sealing If the holding time of the vacuum state in the process is adjusted, the degree of vacuum in the vacuum chamber can be adjusted appropriately.
For example, the degree of vacuum of the vacuum chamber can be increased by increasing the surface roughness, increasing the holding time, or both.

Hereinafter, based on the embodiment concerning the present invention, with reference to drawings, the pressure transducer of the present invention and the manufacturing method for the same are explained in detail.
FIG. 1 shows a cross-sectional configuration of a pressure transducer according to one embodiment of the present invention. The body 71 is made of a metal such as stainless steel, and has, for example, a coupling portion 71a composed of a male screw coupled to a portion to be measured such as a gas insulated switchgear (not shown). It has parts 71b-71e. End 71 ₁ of the outer edge of the hollow portion 71b, along with a substantially V-shaped groove is formed, the tip is made cut in a plane perpendicular to the central axis. On the other hand, also the end portion 71 ₂ of the outer edge of the hollow portion 71e, with a substantially V-shaped groove is formed, the tip is made cut in a plane perpendicular to the central axis. The hollow portion 71b which comes into contact with the end portion 71 ₁ of the coupling portion 71a side of the body 71, as shown in FIG. 1, the cylindrical portion having a rigidity which is integral with the strain-generating diaphragm 72 made of a metal such as stainless steel (rigid portion) 72a Are vacuum-tightly fixed by welding or the like, and a vacuum chamber 73 is formed in a region surrounded by the back surface of the strain-generating diaphragm 72, the hollow portion 71c of the body 71, and the inner surface of an airtight terminal 76 described later.

  As shown in FIG. 3, a substantially V-shaped groove is formed at a corner near the cylindrical portion 72a of the flange portion 72b constituting the strain generating diaphragm 72, and the tip is a surface perpendicular to the central axis. It has been trimmed to become. A strain gauge 74 that converts deformation of the strain-generating diaphragm 72 due to a pressure difference between the pressure-receiving surface and the back surface into an electrical signal is attached to the back surface of the strain-generating diaphragm 72 that forms a part of the vacuum chamber 73, vapor deposition, sputtering, and welding. It is attached by other means. Although not shown, the strain gauge 74 has a thickness of several μm on a gauge base made of, for example, epoxy resin, phenol resin, polyimide resin or the like having excellent electrical insulation, and is made of copper / nickel alloy or nickel / chromium. It is made of an alloy and has a meandering foil-like gauge resistance. Both ends of the gauge resistor are integrally connected to a plurality of gauge tabs (not shown). And each one end of the some copper foil pattern formed on the flexible connection board | substrate 75 which consists of polyimide resin etc. with each gauge tab by solder is connected, respectively.

  An airtight terminal 76 is airtightly fixed to a portion of the hollow portion 71d of the body 71 connected to the hollow portion 71c by soldering using high-temperature solder or the like. The airtight terminal 76 has a cylindrical portion that fits into the hollow portion 71 d of the body 71. Inside the airtight terminal 76, a plurality of rod-shaped pin terminals 77 are supported by an insulating sealing material (not shown) such as glass, and each of the pin terminals 77 has a flexible connection board as described above. The other ends of the plurality of copper foil patterns formed on 75 are connected to each other. Further, in the portion of the hollow portion 71e of the body 71 that is in contact with the hollow portion 71d, the other ends of the plurality of pin terminals 77 constituting the airtight terminal 76 protrude from the back side of the spacer 78, and each pin terminal One end of each of a plurality of copper foil patterns formed on a flexible short circuit board 79 made of polyimide resin or the like is connected to each other end of 77 by solder.

On the other hand, the coupling portion 71a of the body 71 in the hollow portion 71e in contact with the end portion 71 ₂ of the opposite, a metal such as stainless steel, is substantially cylindrical cable gland 80 is fitted, it is fixed to the hermetically by welding ing. The hollow cable gland 80, with cable 81 shielded is inserted, between the outer periphery of the cable 81, in order toward the right from the end in contact with the end portion 71 ₂ of the body 71, an epoxy A filling adhesive 82 made of a synthetic resin such as a resin, a retaining ring 83 and a protective bushing 84 made of Viton rubber or the like are inserted. Further, a reinforcing plate 85 made of glass epoxy resin or the like is attached to the inner surface of the cable gland 80 inserted into the hollow portion 71e of the body 71, and each one end of the plurality of conducting wires 81a constituting the cable 81 is It is held through. Each one end of each conducting wire 81a is connected to each other end of a plurality of copper foil patterns formed on the flexible short circuit board 79. The hollow portion 71e of the body 71 is filled with a filler 86 made of silicon gel or the like.

Next, an assembly method, that is, a manufacturing method of the pressure transducer having the above configuration will be described with reference to FIGS.
(1) First, the hermetic terminal 76 is inserted from the end portion 71 ₁ side to the body 71, the cylindrical portion of the hermetic terminal 76 to the hollow portion 71d of the body 71, the left end portion of the hermetic terminal 76 and the hollow portion 71c of the body 71 It fits so that it may correspond to the step part which exists in the boundary with the hollow part 71d. Next, the cylindrical portion of the airtight terminal 76 is airtightly fixed to the hollow portion 71d of the body 71 by soldering or the like. This process is referred to as an “airtight terminal fixing process”.
(2) Next, each of the other ends of the plurality of copper foil patterns formed on the flexible connection board 75 is connected to each one end of each pin terminal 77 that is penetrated and supported inside the hermetic terminal 76, and strain is generated. One end of each of the plurality of copper foil patterns formed on the flexible connection board 75 is connected to each gauge tab of a strain gauge 74 attached to the back side of the diaphragm 72.
(3) Next, the cylindrical portion 72 a of the strain-generating diaphragm 72 is fitted into the hollow portion 71 b of the body 71. This process is referred to as a “diaphragm attachment process”.

(4) Next, welded sealed as follows with respect to the flange portion 72b of the end portion 71 ₁ and the strain generating diaphragm 72 of the above-mentioned (1) to process the assembled middle products passing through the (3) Body 71 Stop.
(I) First, a vacuum baking process is performed on an intermediate product that has undergone the steps (1) to (3). In this case, an exhaust path for exhausting a gas composed of air, organic matter, or the like from a vacuum chamber 73 formed in a region surrounded by the back surface of the strain generating diaphragm 72, the hollow portion 71c of the body 71, and the inner surface of the airtight terminal 76. Is a microscopic gap between the fitting portion of the cylindrical portion 72a of the strain-generating diaphragm 72 and the hollow portion 71b of the body 71 and the butted surface. This process is referred to as a “vacuum baking process”.

(Ii) Next, the assembled product that has undergone the step (i) described above is cooled in a vacuum and then taken out to the atmosphere. This step is referred to as a “removal processing step”.
(Iii) Next, as shown in FIG. 4, the body of the intermediate product 91 is assembled in a vacuum before the intermediate product 91 having undergone the steps (i) to (ii) is cooled to room temperature. The fixing fitting 92 is fitted into the hollow portion 71e of the 71, and the cooling fitting 93 is fitted to the pressure receiving surface side of the strain-generating diaphragm 72 of the assembling product 91.
(Iv) Next, after maintaining the vacuum state in the step (iii) for a certain period of time, an electron beam welding apparatus (not shown) is driven, and the electron beam emitted from the electron gun is subjected to strain generation of the structure shown in FIG. the abutting portion of the end portion 71 ₁ of the end face and the body 71 of the flange portion 72b of the diaphragm 72, by irradiating, as shown by the enlarged arrow in Figure 5, the end portion 71 ₁ and the strain generating diaphragm 72 of the body 71 The flange portion 72 b is welded and sealed, and a vacuum chamber 73 is formed in a region surrounded by the back surface of the strain-generating diaphragm 72, the hollow portion 71 c of the body 71 and the inner surface of the airtight terminal 76.

In this case, the gap of the spigot portion 94 (see FIG. 5) in which the cylindrical portion 72a of the strain-generating diaphragm 72 is inserted into the hollow portion 71b of the body 71 serves to protect important components such as the strain gauge 72 from spatter and welding gas. At the same time, it also functions as an exhaust path when evacuating. This process is referred to as a “vacuum chamber forming process”.
(V) Next, after removing the fixing metal fitting 92 and the cooling metal fitting 93 from the structure shown in FIG. 4 that has undergone the above-described steps (i) to (iv), the welded state of the welded part of the intermediate product 91 is examined with a microscope. Inspect with. The process (4) described above is referred to as a “diaphragm fixing process”.
(5) Next, one end of each of the plurality of copper foil patterns formed on the flexible short circuit board 79 is connected to each other end of the plurality of pin terminals 77 constituting the airtight terminal 76.

(6) Next, a cable gland 80 to which a cable 81, a filling adhesive 82, a retaining ring 83, a protective bush 84, and a reinforcing plate 85 are attached is prepared, and the cable that is penetrated and held by the reinforcing plate 85 of this structure. One end of each of the plurality 81 of conductive wires 81a and each other end of the plurality of copper foil patterns formed on the flexible short-circuit board 79 that is an intermediate product that has undergone the steps (1) to (5) described above. Connecting.
(7) Next, after filling the hollow portion 71e of the body 71 with the filler 86, the cable gland 80 of the structure that has undergone the step (6) is fitted into the hollow portion 71e of the body 71, and the cable gland 80 And the body 71 are fixed by welding or the like.
As described above, according to the above-described embodiment of the present invention, the air from the vacuum chamber 73 formed in the region surrounded by the back surface of the strain-generating diaphragm 72, the hollow portion 71c of the body 71, and the inner surface of the airtight terminal 76 is obtained. And an opening (exhaust passage) for discharging a gas made of organic matter or the like includes a fitting portion between the cylindrical portion 72a of the strain-generating diaphragm 72 and the hollow portion 71b of the body 71 and a side surface of the collar portion 72b of the strain-generating diaphragm 72. and a microscopic gap butting surface of the end portion 71 ₁ of the body 71. This microscopic gap is inevitably formed by abutting surfaces having surface roughness inevitable in processing.

  Therefore, unlike the first conventional example described in Patent Document 1 described above, it is not necessary to provide the exhaust pipe 12 only for exhaust, and the number of parts can be reduced correspondingly, and the exhaust pipe 12 is manufactured. Cost reduction because the process of attaching, exhaust pipe 12, the process of crushing and sealing exhaust pipe 12, and the process of filling molten solder into tip opening 12 a of exhaust pipe 12 can be reduced. In addition, there are no structural restrictions on the position and the degree of freedom in design is great. Further, even when the pressure transducer is downsized, there is no need for parts only for exhaust, and it is only necessary to downsize each part. The accompanying inconvenience does not occur. In addition, since the microscopic gap also serves as an opening for vacuum sealing, as in the second conventional example described above, sealing that is easy to weld only for vacuum sealing There is no need to provide the metal fitting 31, and the number of parts can be reduced by that amount, and the steps for producing the sealing metal fitting 31, the step for attaching the sealing metal fitting 31, and the step for sealing the sealing metal fitting 31 by welding are reduced. Therefore, the cost can be reduced, and there is no positional restriction in terms of structure, and the degree of freedom in design is great.

In addition, since there are few places to be welded, there is less risk of gas leakage due to work defects and the like, thereby improving reliability. Further, since the microscopic gap is smaller than the opening of the inner cylindrical portion 31c constituting the sealing metal fitting 31 of the second conventional example, the amount of welding gas that enters the vacuum chamber 73 during welding sealing. As a result, the degree of vacuum in the vacuum chamber 73 can be increased more than before, and the amount of metal deposition on the internal parts due to the welding gas can be reduced, so that failures caused by the metal deposited on the internal parts can be reduced. .
Further, according to the present embodiment, the gap of the spigot portion 94 (see FIG. 5) in which the cylindrical portion 72a of the strain-generating diaphragm 72 is inserted into the hollow portion 71b of the body 71 is important for the strain gauge 72 and the like from spatter and welding gas. It plays the role of protecting the parts. Therefore, according to the present embodiment, unlike the second conventional example described above, it is not necessary to provide the deposition preventing plate 32 only for protecting important parts such as strain gauges from spatter and welding gas. The number of parts can be reduced. Moreover, the process of assembling the vapor deposition prevention plate 32 and the process of welding the vapor deposition prevention plate 32 to the sealing metal fitting 31 can be reduced. Thereby, cost reduction can be aimed at.

In addition, according to the present embodiment, the surface roughness of the cylindrical portion 72a of the strain-generating diaphragm 72 and the surface roughness of the hollow portion 71b of the body 71 and the vacuum state maintained in the vacuum sealing step (4) (iv) described above. By adjusting the time, the degree of vacuum in the vacuum chamber 73 can be adjusted appropriately. For example, the degree of vacuum of the vacuum chamber 73 can be increased by increasing the surface roughness, increasing the holding time, or both.
As described above, according to the present embodiment, the number of parts and processes can be reduced, the degree of design freedom in terms of structure and dimensions is improved, and it is inexpensive and easy to assemble. Highly reliable pressure transducer can be assembled.
Although the present embodiment has been described in detail with reference to the drawings, the specific configuration is not limited to the present embodiment, and various modifications can be made without departing from the scope of the present invention. Of course you can.

For example, in the above-described embodiment, an example in which the present invention is applied to a vacuum-sealed pressure transducer has been shown. However, the present invention is not limited to this, and the present invention is not limited to an air-sealed pressure transducer or an inert gas transducer. You may apply to a gas-sealed pressure transducer.
Further, in the above-described embodiment, the example in which the pressure receiving surface of the strain-generating diaphragm 72 is exposed has been described. However, the present invention is not limited to this, and as in the first and second conventional examples described above, the portion to be measured A pressure introducing path for introducing the fluid pressure to be measured may be formed between the pressure receiving surface of the strain generating diaphragm 72 and the pressure receiving surface. Moreover, in embodiment mentioned above, although the body 71 showed the example which has the hollow parts 71b-71e from which diameter differs, respectively, it is not limited to this, The diameters of the hollow parts 71b-71e may all be equal, The shape of the hollow portion is not limited to a circular shape, and may be a quadrangular shape or a polygonal shape that is a pentagon or more.
Further, in the above embodiment, although an example of using an electron beam welding apparatus to weld sealing the flange portion 72b of the end portion 71 ₁ and the strain generating diaphragm 72 of the body 71 is not limited to this An apparatus capable of welding the opening in vacuum, for example, a vacuum brazing apparatus may be used. In the above-described embodiment, an example in which the present invention is applied to a pressure transducer having a vacuum chamber has been described. However, the present invention is not limited to this, and the present invention is not limited to a load transducer or a general hermetic container. You may apply when sealing.

It is sectional drawing which shows the structure of the pressure converter which concerns on one embodiment of this invention. It is sectional drawing which shows the structure of the body which comprises the pressure converter shown in FIG. It is sectional drawing which shows the structure of the strain generating diaphragm which comprises the pressure converter shown in FIG. It is sectional drawing for demonstrating the welding sealing process at the time of assembling the pressure converter shown in FIG. It is the elements on larger scale of FIG. It is sectional drawing which shows the structure of the pressure converter in a 1st prior art example. It is sectional drawing which shows the structure of the pressure converter in a 2nd prior art example. It is sectional drawing which shows the structure of the airtight terminal and pin terminal which are used for the pressure converter shown in FIG. (A), (b) of this figure is each a fragmentary sectional view of the airtight terminal of FIG. (A) and (b) of this figure are the top view and sectional drawing which show the structure of the sealing metal fitting and vapor deposition prevention board which are used for the pressure converter shown in FIG. It is the elements on larger scale of FIG.10 (b). It is an expanded sectional view of the terminal pipe of the pressure converter in the 2nd prior art example shown in FIG. It is the elements on larger scale of FIG. (A) And (b) of this figure is the top view and right view which show the structure of the welding rod used for the pressure transducer in the 2nd prior art example shown in FIG. It is the schematic for demonstrating the 1st welding sealing process among the assembly methods of the pressure converter in a 2nd prior art example. It is the schematic for demonstrating the 2nd welding sealing process among the assembly methods of the pressure converter in a 2nd prior art example.

Explanation of symbols

71 Body 71a Connecting portion 71b to 71e Hollow portion 71 ₁ , 71 ₂ End portion 72 Strain diaphragm 72a Cylindrical portion 72b Collar portion 73 Vacuum chamber 74 Strain gauge 75 Flexible connection substrate 76 Airtight terminal 77 Pin terminal 79 Flexible short circuit board 80 Cable ground 81 Cable 82 Filling adhesive 83 Retaining ring 84 Protective bushing 85 Reinforcement plate 86 Filling agent 91 Assembly part 92 Fixing fitting 93 Cooling fitting 94 Inlay part

Claims (3)

A pressure transducer that converts a deformation of a diaphragm due to a pressure difference between a pressure receiving surface and a back surface thereof into an electrical signal using a strain gauge attached to the back surface of the diaphragm,
The body has first and second hollow portions with different diameters, and an airtight terminal is fitted into the second hollow portion of the body having at least one end opened, and the second hollow portion of the body An airtight terminal adhering process for adhering airtightly,
The rigid body portion of the diaphragm having a rigid body portion and a flange portion is fitted to the first hollow portion from the opening portion of the body with a small gap, and the flange portion is fitted to the opening portion of the body. A diaphragm mounting step for contacting with
Under vacuum conditions, the opening of the body and the flange of the diaphragm are sealed by welding or brazing, and the back surface of the diaphragm, the first hollow portion of the body, and the inner surface of the hermetic terminal A diaphragm fixing step for forming a vacuum chamber in a region surrounded by
The manufacturing method of the pressure transducer characterized by being assembled by this. In the diaphragm fixing step, the vacuum chamber is vacuum-baked by evacuating the vacuum chamber from the abutment surface of the diaphragm and the body while heating the intermediate product after the diaphragm mounting step at a predetermined temperature. 2. The method of manufacturing a pressure transducer according to claim 1, further comprising a vacuum baking step for discharging outgas and moisture released from the organic matter and deposits in the room. The diaphragm adhering step is a process of taking out the assembled product that has undergone the vacuum baking step to a predetermined temperature in a vacuum, and then taking it out to the atmosphere.
A vacuum in which the vacuum chamber is formed by performing a predetermined vacuum state again before cooling the assembled product that has undergone the removal step to room temperature, holding the vacuum state for a predetermined time, and then sealing by welding or brazing. The method for manufacturing a pressure transducer according to claim 2 , further comprising a chamber forming process.

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