JP7077210B2 - Manufacturing method of pressure detector, circuit built-in member, pressure detector - Google Patents

Description

The present invention relates to a pressure detection device, a circuit built-in member, and a method for manufacturing the pressure detection device.

For example, in a device such as an automobile having an internal combustion engine, a plurality of detection devices for detecting pressure, temperature, and the like are mounted in the device. Then, based on the detection result by these detection devices, a control device called an ECU (Engine Control Unit) controls the operation of the internal combustion engine and the like.

Patent Document 1 has a piezoelectric element that detects a change in pressure, a circuit board that is connected to the positive electrode side of the piezoelectric element and is provided with a processing circuit that processes the output signal of the piezoelectric element, and has conductivity. Moreover, the accommodating member arranged so as to cover the circuit board, connected to the negative electrode side of the piezoelectric element, and connected to the ground of the processing circuit via the ground plate provided on the circuit board side, the piezoelectric element, the circuit board, and the accommodating member. Described is a pressure detector that houses the accommodating member internally and includes a detection element, a circuit board, and a housing that is electrically insulated from the accommodating member.

Japanese Unexamined Patent Publication No. 2017-173122

Here, when a configuration is adopted in which the accommodating member and the ground plate provided on the circuit board side are simply brought into contact with each other, for example, when an impact is applied to the pressure detection device from the outside, the accommodating member and the accommodating member Was separated, and there was a risk that the electrical path would be cut off.
An object of the present invention is to improve the reliability of the electrical connection between the piezoelectric element and the processing circuit.

The pressure detection device of the present invention has a piezoelectric element that outputs an electric signal corresponding to a pressure received from the outside, an accommodating member having conductivity to which one end of the piezoelectric element is connected, and the other end of the piezoelectric element. A processing circuit that is connected and processes the electrical signal, a sealing portion that has insulation and seals the processing circuit, and a conductive and conductive one that is connected to the processing circuit and the other. Has a conductive portion exposed to the outside of the side surface of the sealing portion, and includes a circuit built-in member in which the conductive portion abuts on the accommodating member by being accommodated in the accommodating member.
In such a pressure detecting device, the conductive portion in the circuit built-in member can be characterized by being composed of a leaf spring having a restoring force from the side surface of the sealing portion toward the accommodating member.
Further, the sealing portion in the circuit built-in member may be provided behind the conductive portion and may have a protrusion protruding from the side surface of the sealing portion toward the accommodating member.
Further, the sealing portion in the circuit built-in member is provided on the back side of the protrusion in the sealing portion, and further has another protrusion protruding from the side surface of the sealing portion toward the accommodating member. Can be a feature.
Further, the accommodating member is provided with a hole penetrating the inner surface and the outer surface of the accommodating member, and the conductive portion provided in the circuit built-in member is arranged at the hole forming portion to form the hole. It can be characterized in that the accommodating member and the conductive portion are joined at a portion.
Further, the piezoelectric element is housed inside the accommodating member, has conductivity, is accommodated inside the accommodating member, and is connected to the piezoelectric element and the processing circuit to transmit the electric signal. It further has a conduction member that conducts to the processing circuit, and one pole side of the piezoelectric element is connected to the conduction member, and the other pole side of the piezoelectric element is connected to the accommodation member. can do.
Further, the accommodation member may be accommodated inside, and a housing portion electrically insulated from the accommodation member may be further provided.
From another point of view, the circuit built-in member of the present invention includes a processing circuit to which one end of a piezoelectric element that outputs an electric signal corresponding to a pressure received from the outside is connected and a processing circuit that processes the electric signal. It has a sealing portion that has insulating properties and seals the processing circuit, and a conductive portion that has conductivity and one of which is connected to the processing circuit and the other is exposed on the side surface of the sealing portion. is doing.
From another point of view, the method for manufacturing the pressure detection device of the present invention has a processing circuit that processes an electric signal supplied from one pole side of the piezoelectric element, and has insulation property and the processing circuit. A step of preparing a circuit built-in member having a sealing portion for sealing and a conductive portion having conductivity and one of which is connected to the processing circuit and the other of which is exposed to the outside of the side surface of the sealing portion. And, the step of accommodating the circuit built-in member with respect to the accommodating member which has conductivity and is connected to the other pole side of the piezoelectric element is included.
In the method of manufacturing such a pressure detecting device, the conductive portion in the circuit built-in member is characterized by being formed of a leaf spring having a restoring force from the side surface of the sealing portion toward the accommodating member. be able to.
Further, the sealing portion in the circuit built-in member may be provided behind the conductive portion and may have a protrusion protruding from the side surface of the sealing portion toward the accommodating member.
Further, the sealing portion in the circuit built-in member is provided on the back side of the protrusion in the sealing portion, and further has another protrusion protruding from the side surface of the sealing portion toward the accommodating member. Can be a feature.
Further, the accommodating member is provided with a hole penetrating the inner surface and the outer surface of the accommodating member, and the conductive portion provided in the circuit built-in member is arranged at the forming portion of the hole, and the accommodating member is provided. It is possible to further include a step of joining the accommodating member and the conductive portion at the hole forming portion after accommodating the circuit built-in member in the member.

According to the present invention, the reliability of the electrical connection between the piezoelectric element and the processing circuit can be improved.

It is a schematic block diagram of the pressure detection system which concerns on embodiment. It is a side view of the pressure detection device. It is sectional drawing (III-III sectional view of FIG. 2) of the pressure detection apparatus. It is an enlarged sectional view of the tip side (IV region of FIG. 3) of a pressure detection device. It is an exploded sectional view of the 1st internal housing, the 2nd internal housing, the pressurizing member, the 1st insulating member and the 2nd insulating member constituting the pressure detection device. (A) is a perspective view of the first accommodating member provided in the pressure detecting device, and (b) is a perspective view of the second accommodating member provided in the pressure detecting device. It is a perspective view of the circuit built-in member provided in the pressure detection device. It is a perspective view of the circuit built-in member before the metal plate is bent. It is sectional drawing (IX-IX sectional drawing of FIG. 7) of the circuit built-in member. It is a schematic block diagram of the circuit board provided in the circuit built-in member.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[Composition of pressure detection system]
FIG. 1 is a schematic configuration diagram of a pressure detection system 1 according to an embodiment.
The pressure detection system 1 supplies power to the pressure detection device 20 for detecting the pressure (combustion pressure) in the combustion chamber C in the internal combustion engine 10 and the pressure detection device 20, and is based on the pressure detected by the pressure detection device 20. It includes a control device 100 that controls the operation of the internal combustion engine 10, and a connection cable 80 that electrically connects the pressure detection device 20 and the control device 100.

Here, the internal combustion engine 10 whose pressure is to be detected includes a cylinder block 11 in which a cylinder is formed, a piston 12 that reciprocates in the cylinder, and a combustion chamber C that is fastened to the cylinder block 11 together with the piston 12 and the like. It has a cylinder head 13 constituting the above. Further, the cylinder head 13 is provided with a communication hole 13a for communicating the combustion chamber C with the outside. Then, the pressure detecting device 20 is attached to the internal combustion engine 10 by inserting the tip side of the pressure detecting device 20 into the communication hole 13a and fixing the pressure detecting device 20 to the cylinder head 13. Here, the cylinder block 11, the piston 12, and the cylinder head 13 constituting the internal combustion engine 10 are made of a conductive metal material such as cast iron or aluminum.

[Composition of pressure detector]
FIG. 2 is a side view of the pressure detecting device 20. Further, FIG. 3 is a cross-sectional view of the pressure detection device 20 (Cross-sectional view of III-III in FIG. 2). Further, FIG. 4 is an enlarged cross-sectional view of the tip end side (IV region in FIG. 3) of the pressure detecting device 20. Furthermore, FIG. 5 shows a first internal housing 35, a second internal housing 36, a pressure member 49, a first insulating member 51, and a second insulating member 52 (for details of each), which constitutes the pressure detection device 20. It is an exploded sectional view of) (which will be described later).

The pressure detecting device 20 includes a housing portion 30 which has a tubular shape as a whole and is provided so as to be exposed to the outside, and various mechanisms for detecting pressure, and almost the entire pressure detecting device 20 is housed inside the housing portion 30. It also has a detection mechanism portion 40 provided so that a part thereof is exposed to the outside, and a seal portion 70 attached to the outer peripheral surface of the housing portion 30. Then, in the pressure detecting device 20, the left side in FIG. 2 faces the combustion chamber C (lower side in FIG. 1) and the right side in FIG. 2 faces the outside (upper side in FIG. 1) with respect to the internal combustion engine 10 shown in FIG. It is installed so that it faces. In the following description, in FIG. 2, the side toward the left in the figure is referred to as the “tip side” of the pressure detection device 20, and the side toward the right in the figure is referred to as the “rear end side” of the pressure detection device 20. Further, in the following description, the direction of the center line of the pressure detecting device 20 shown by the alternate long and short dash line in FIG. 2 and the like is simply referred to as “center line direction”.

(Structure of housing)
The housing portion 30 includes a tip outer housing 31, a diaphragm head 32 attached to the tip side of the tip outer housing 31, and an intermediate outer housing 33 attached to the rear end side of the tip outer housing 31. It is provided with a rear end external housing 34 attached to the rear end side of the intermediate external housing 33. Further, the housing portion 30 is the first inner housing 35 inside the tip outer housing 31 and attached to the rear end side of the diaphragm head 32, and the first inside inside the tip outer housing 31. It further includes a second internal housing 36 attached to the rear end side of the housing 35.

[External tip housing]
The tip outer housing 31 is a member having a hollow structure and having a cylindrical shape as a whole. The tip outer housing 31 is made of a metal material such as stainless steel, which has conductivity and high heat resistance and acid resistance.

[Diaphragm head]
The diaphragm head 32 is a member having a disk shape as a whole. The diaphragm head 32 is made of a metal material such as stainless steel, which has conductivity and high heat resistance and acid resistance. In this example, the diaphragm head 32 and the tip outer housing 31 are made of the same material.

As shown in FIG. 4, the diaphragm head 32 has a surface center recess 32b formed in the central portion on the tip side, and a pressure receiving surface (surface) that receives pressure by being exposed to the outside (combustion chamber C side). It has 32a. Further, the diaphragm head 32 has a back surface annular recess 32c formed by cutting out the back surface of the pressure receiving surface 32a in an annular shape, and the presence of the back surface annular recess 32c results in a central portion of the pressure receiving surface 32a. It has a back surface central convex portion 32d that protrudes toward the rear end side from the front surface central concave portion 32b formation portion). Further, the diaphragm head 32 has a back surface annular flat portion 32e formed by cutting out the peripheral edge portion on the back surface of the pressure receiving surface 32a in an annular shape, and the back surface annular concave portion 32c and the back surface annular flat portion 32e as a result. It has a back surface annular convex portion 32f protruding from the periphery of the central convex portion 32d toward the rear end side.

The diaphragm head 32 is provided so as to close the opening on the tip side of the tip outer housing 31. More specifically, the tip end side of the tip outer housing 31 abuts on the back surface annular flat portion 32e of the diaphragm head 32. Then, laser welding is applied to the boundary portion between the diaphragm head 32 and the tip outer housing 31 over one circumference of the outer peripheral surface.

[Intermediate external housing]
The intermediate outer housing 33 is a member having a hollow structure and having a cylindrical shape as a whole. The intermediate outer housing 33 is made of a metal material such as stainless steel, which has conductivity and high heat resistance and acid resistance.

The tip end side of the intermediate outer housing 33 is fitted into the rear end side of the tip outer housing 31. Then, laser welding is applied to the boundary portion between the intermediate outer housing 33 and the tip outer housing 31 over the entire circumference of the outer peripheral surface.

[Rear end external housing]
The rear end outer housing 34 is a member having a hollow structure and having a cylindrical shape as a whole. The rear end outer housing 34 is made of a metal material such as stainless steel, which has conductivity and high heat resistance and acid resistance.

The front end side of the rear end outer housing 34 is fitted into the rear end side of the intermediate outer housing 33. Laser welding is not applied to the boundary between the rear end outer housing 34 and the intermediate outer housing 33.

[First internal housing]
The first internal housing 35 is a member having a hollow structure and having a cylindrical shape as a whole. The first internal housing 35 is made of a metal material such as stainless steel, which has conductivity and high heat resistance and acid resistance.

As shown in FIG. 5, the first internal housing 35 has a first tip cylindrical portion 351 located at the most distal end side and a first rear end cylinder located at the rear end side of the first tip tubular portion 351. It has a shaped portion 352. In the first internal housing 35, the outer diameter of the first rear end cylindrical portion 352 is larger than that of the first tip cylindrical portion 351 and the first outer step portion 353 is provided at the boundary between the two. ing. Further, the through hole provided inside the first internal housing 35 has an inner diameter that gradually increases from the front end side to the rear end side, and is inside the first rear end cylindrical portion 352. A first inner step portion 354 is provided at the portion to be.

The tip end side of the first internal housing 35 abuts on the rear end side of the diaphragm head 32. More specifically, the surface on the tip end side of the first outer step portion 353 in the first inner housing 35 abuts on the surface on the rear end side of the back surface annular convex portion 32f in the diaphragm head 32. At this time, the first tip cylindrical portion 351 in the first internal housing 35 is located inside the back surface annular recess 32c in the diaphragm head 32. Then, laser welding is applied to the boundary portion between the first internal housing 35 and the diaphragm head 32 over the entire circumference of the outer peripheral surface.

[Second internal housing]
The second internal housing 36 is a member having a hollow structure and having a cylindrical shape as a whole. The second inner housing 36 is made of a metal material such as stainless steel, which has conductivity and high heat resistance and acid resistance.

As shown in FIG. 5, the second internal housing 36 has a second tip cylindrical portion 361 located on the most tip side and a second rear end cylinder located on the rear end side of the second tip tubular portion 361. It has a shape portion 362 and a shape portion 362. In the second internal housing 36, the outer diameter of the second rear end cylindrical portion 362 is larger than that of the second tip tubular portion 361, and a second outer step portion 363 is formed at the boundary between the two. ing. Further, the inner diameter of the through hole provided inside the first internal housing 35 is substantially constant.

The tip end side of the second inner housing 36, that is, the tip end side of the second tip cylindrical portion 361 is accommodated inside the first rear end cylindrical portion 352 of the first inner housing 35. Further, the surface on the front end side of the second internal housing 36 abuts on the surface on the rear end side of the second insulating member 52 (details will be described later). At this time, the rear end side of the second tip cylindrical portion 361 and the second rear end cylindrical portion 362 are exposed to the rear end side of the first inner housing 35. Then, laser welding is applied to the boundary portion between the second inner housing 36 and the first inner housing 35 over one circumference of the outer peripheral surface.

(Structure of detection mechanism)
The detection mechanism unit 40 includes a piezoelectric element 41, a tip electrode member 42, a tip insulating member 43, a rear end electrode member 44, and a rear end insulating member 45. Further, the detection mechanism unit 40 includes a first coil spring 46, a conduction member 47, a holding member 48, a pressure member 49, and an insulating pipe 50. Further, the detection mechanism unit 40 includes a first insulating member 51, a second insulating member 52, a support member 53, and a second coil spring 54. Furthermore, the detection mechanism unit 40 includes a first accommodating member 55, a second accommodating member 56, a circuit built-in member 57, a connecting member 58, a closing member 59, and a third insulating member 60.

〔Piezoelectric element〕
The piezoelectric element 41 is a member that exhibits a columnar shape as a whole. The piezoelectric element 41 includes a piezoelectric body that exhibits a piezoelectric action of the piezoelectric vertical effect. The piezoelectric element 41 is arranged inside the tip outer housing 31 (and the first inner housing 35).

Here, the piezoelectric vertical effect means that when an external force is applied to a stress application axis in the same direction as the charge generation axis of the piezoelectric body, charge is generated on the surface of the piezoelectric body in the charge generation axis direction. Therefore, in this example, a signal (charge signal) due to the generated charge is output to the front end side surface and the rear end side surface of the piezoelectric element 41 in response to the change in pressure along the center line direction. Become.

Next, a case where the piezoelectric lateral effect is used for the piezoelectric element 41 will be illustrated. The piezoelectric lateral effect means that when an external force is applied to a stress application axis located at a position orthogonal to the charge generation axis of the piezoelectric body, a charge is generated on the surface of the piezoelectric body in the direction of the charge generation axis. A plurality of piezoelectric bodies formed thinly in the shape of a thin plate may be laminated, and by laminating in this way, the electric charge generated in the piezoelectric body can be efficiently collected and the sensitivity of the sensor can be increased. Examples of the piezoelectric material that can be used in the piezoelectric element 41 include langasite crystals (langasite, langateite, langanite, LTGA) having a piezoelectric longitudinal effect and a piezoelectric lateral effect, crystals, gallium phosphate, and the like. can do.

[Tip electrode member]
The tip electrode member 42 is a member that exhibits a columnar shape as a whole. The tip electrode member 42 is made of a metal material such as stainless steel, which has high conductivity and high heat resistance. The tip electrode member 42 is arranged inside the tip outer housing 31 and on the tip side of the piezoelectric element 41 so that the surface on the rear end side of the tip electrode member 42 comes into contact with the surface on the tip side of the piezoelectric element 41. It has become. Further, the outer diameter of the tip electrode member 42 is larger than the outer diameter of the piezoelectric element 41.

[Tip insulation member]
The tip insulating member 43 is a member that exhibits a columnar shape as a whole. The tip insulating member 43 is made of a ceramic material such as alumina, which has insulating properties and high heat resistance. The tip insulating member 43 is arranged inside the tip outer housing 31 and on the tip side of the tip electrode member 42, and the surface on the rear end side of the tip insulating member 43 comes into contact with the surface on the tip side of the tip electrode member 42. It is designed to do. On the other hand, the surface on the tip side of the tip insulating member 43 comes into contact with the surface on the rear end side of the back surface central convex portion 32d provided on the diaphragm head 32. Further, the outer diameter of the tip insulating member 43 is smaller than the outer diameter of the tip electrode member 42, and is larger than the outer diameter of the back surface center convex portion 32d in the diaphragm head 32.

[Rear end electrode member]
The rear end electrode member 44 is a member that exhibits a columnar shape as a whole. The rear end electrode member 44 is made of a metal material such as stainless steel, which has high conductivity and high heat resistance. The rear end electrode member 44 is arranged inside the front end outer housing 31 and on the rear end side of the piezoelectric element 41, and the front end side surface of the rear end electrode member 44 is the rear end side surface of the piezoelectric element 41. It is designed to come into contact. Further, the outer diameter of the rear end electrode member 44 is larger than the outer diameter of the piezoelectric element 41.

[Rear end insulation member]
The rear end insulating member 45 is a member having a hollow structure and exhibiting an annular shape (cylindrical shape) as a whole. The rear end insulating member 45 is made of a ceramic material such as alumina, which has insulating properties and high heat resistance. The rear end insulating member 45 is arranged inside the front end outer housing 31 and on the rear end side of the rear end electrode member 44, and the surface of the rear end insulating member 45 on the front end side is the rear end of the rear end electrode member 44. It is designed to come into contact with the side surface. Further, the outer diameter of the rear end insulating member 45 is larger than the outer diameters of the piezoelectric element 41, the tip electrode member 42, and the rear end electrode member 44.

[1st coil spring]
The first coil spring 46 is a member that exhibits a spiral shape as a whole, and is adapted to expand and contract in the center line direction. The first coil spring 46 is made of a conductive metal material such as brass, and its surface is gold-plated. The first coil spring 46 is arranged inside the tip outer housing 31. More specifically, the tip end side of the first coil spring 46 is arranged inside the through hole provided in the rear end insulating member 45, and the tip end thereof is the surface on the rear end side of the rear end electrode member 44. It is designed to come into contact with. On the other hand, the rear end side of the first coil spring 46 protrudes to the rear end side of the rear end insulating member 45. Further, the outer diameter of the first coil spring 46 is smaller than the inner diameter of the through hole provided in the rear end insulating member 45.

[Conduction member]
The conduction member 47 is a member having a rod shape as a whole. The conductive member 47 is made of a conductive metal material such as brass, and its surface is gold-plated. The conduction member 47 includes a tip rod-shaped portion 471 located on the most tip side, an intermediate rod-shaped portion 472 located on the rear end side of the tip rod-shaped portion 471, and a rear end rod-shaped portion 473 located on the rear end side of the intermediate rod-shaped portion 472. And have. Further, in the conduction member 47, the outer diameter increases in the order of the tip rod-shaped portion 471, the intermediate rod-shaped portion 472, and the rear end rod-shaped portion 473. The conduction member 47 is arranged inside the tip outer housing 31. More specifically, the tip end side of the conduction member 47, that is, the tip end side of the tip rod-shaped portion 471 is inserted into the rear end side of the first coil spring 46 and is arranged inside the rear end insulating member 45. However, unlike the first coil spring 46, the tip of the tip rod-shaped portion 471 is not in contact with the surface on the rear end side of the rear end electrode member 44. At this time, the rear end of the first coil spring 46 abuts on the boundary portion (step portion) between the tip rod-shaped portion 471 and the intermediate rod-shaped portion 472 in the conduction member 47. As a result, the first coil spring 46 is sandwiched between the rear end electrode member 44 and the conduction member 47, so that the first coil spring 46 is compressed in the center line direction. On the other hand, the intermediate rod-shaped portion 472 and the rear end rod-shaped portion 473 of the conduction member 47 protrude to the rear end side of the rear end insulating member 45. Further, the outer diameter of the tip rod-shaped portion 471 is smaller than the inner diameter of the first coil spring 46, and the outer diameter of the intermediate rod-shaped portion 472 is larger than the inner diameter of the first coil spring 46.

[Holding member]
The holding member 48 is a member having a hollow structure and having a cylindrical shape as a whole. The holding member 48 is made of a synthetic resin material such as PPT (Polypropylene Terephthalate) having insulating properties. The holding member 48 has a tip portion located on the most tip side, an intermediate portion located on the rear end side of the tip portion, and a rear end portion located on the rear end side of the middle portion. In the holding member 48, the outer diameter increases in the order of the tip portion, the middle portion, and the rear end portion. The holding member 48 is arranged so as to straddle the inside of the tip outer housing 31 and the inside of the intermediate outer housing 33. The conduction member 47 is housed and held inside the holding member 48. More specifically, the holding member 48 houses the rear end side of the conduction member 47, that is, the rear end side of the rear end rod-shaped portion 473. As a result, of the conduction member 47, the tip rod-shaped portion 471 and the intermediate rod-shaped portion 472 and the tip end side of the rear end rod-shaped portion 473 protrude to the tip end side of the holding member 48. On the other hand, a recess is formed at the rear end of the holding member 48 from the rear end side to the front end side. Further, the inner diameter of the hole provided in the holding member 48 is slightly larger than the outer diameter of the rear end rod-shaped portion 473 of the conductive member 47, and the conductive member 47 and the holding member 48 are press-fitted ( clearance fit). ) Is integrated.

[Pressurized member]
The pressurizing member 49 is a member having a hollow structure and having a cylindrical shape as a whole. The pressure member 49 is made of a metal material such as stainless steel, which has high conductivity and high heat resistance. The pressurizing member 49 is inside the tip outer housing 31, and is arranged so as to straddle the inside of the first inner housing 35 and the inside of the second inner housing 36.

As shown in FIG. 5, the pressure member 49 includes a first tubular portion 491 located on the most distal end side, a second tubular portion 492 located on the rear end side of the first tubular portion 491, and the first tubular portion 49. It has a third tubular portion 493 located on the rear end side of the two tubular portions 492 and a fourth tubular portion 494 located on the rear end side of the third tubular portion 493. In the pressure member 49, the outer diameter of the second tubular portion 492 is larger than that of the first tubular portion 491, and the first step portion 495 is formed at the boundary between the two. Further, the outer diameter of the third tubular portion 493 is larger than that of the second tubular portion 492, and a second step portion 496 is formed at the boundary between the two. Further, the outer diameter of the fourth tubular portion 494 is smaller than that of the third tubular portion 493, and a third step portion 497 is formed at the boundary between the two. In this example, the outer diameters of the second cylindrical portion 492 and the fourth tubular portion 494 are set to be substantially the same. Further, the through hole provided inside the pressurizing member 49 has an inner diameter that gradually increases from the front end side to the rear end side, and is located inside the first tubular portion 491. Is provided with a fourth step portion 498.

A piezoelectric element 41, a tip electrode member 42, a rear end electrode member 44, a rear end insulating member 45, a first coil spring 46, and the like are housed inside a through hole provided in the pressurizing member 49. Then, the surface on the rear end side of the fourth step portion 498 provided on the pressure member 49 comes into contact with the surface on the tip end side of the tip electrode member 42. Further, the tip insulating member 43 is arranged in the opening on the tip side of the through hole provided in the pressurizing member 49.

The outer diameter of the first tubular portion 491 of the pressurizing member 49 is smaller than the inner diameter of the tip end side of the first inner step portion 354 of the first inner housing 35. Further, the outer diameters of the second cylindrical portion 492, the third tubular portion 493, and the fourth tubular portion 494 are larger than the inner diameter on the rear end side of the first inner step portion 354 of the first inner housing 35. It's getting smaller. Further, the outer diameter of the fourth tubular portion 494 is smaller than the inner diameter of the second inner housing 36.

On the other hand, the inner diameter of the through hole provided in the pressurizing member 49 is larger than the outer diameter of each of the piezoelectric element 41, the tip electrode member 42, the rear end electrode member 44, and the rear end insulating member 45. Further, the inner diameter of the opening on the tip end side of the through hole provided in the pressure member 49 is larger than the outer diameter of the tip insulating member 43.

[Insulated pipe]
The insulating pipe 50 is a member having a hollow structure and having a cylindrical shape as a whole. The insulating pipe 50 is made of a synthetic resin material such as LCP (Liquid Crystal Polymer) having insulating properties. The insulating pipe 50 is located inside the tip outer housing 31 and inside the pressurizing member 49. Then, the surface on the tip end side of the insulating pipe 50 comes into contact with the surface on the rear end side of the fourth step portion 498 provided on the pressurizing member 49. Inside the insulating pipe 50, a piezoelectric element 41, a front end electrode member 42, a rear end electrode member 44, and a front end side of the rear end insulating member 45 are housed. The outer diameter of the insulating pipe 50 is smaller than the inner diameter of the through hole provided in the pressurizing member 49, and is larger than the inner diameter of the opening provided on the tip end side of the through hole. Further, the inner diameter of the insulating pipe 50 is larger than the outer diameters of the piezoelectric element 41, the tip electrode member 42, the rear end electrode member 44, and the rear end insulating member 45.

[First insulating member]
The first insulating member 51 is a member that exhibits an annular shape as a whole. The first insulating member 51 is made of a ceramic material such as alumina, which has insulating properties and high heat resistance. The first insulating member 51 is located inside the tip outer housing 31, inside the first inner housing 35, and outside the pressurizing member 49. Then, the surface on the tip end side of the first insulating member 51 comes into contact with the surface on the rear end side of the first inner step portion 354 in the first inner housing 35, and the surface on the rear end side of the first insulating member 51 becomes. The pressure member 49 comes into contact with the surface on the tip end side of the second step portion 496. The outer diameter of the first insulating member 51 is smaller than the inner diameter on the rear end side of the first inner step portion 354 of the first inner housing 35. Further, the inner diameter of the first insulating member 51 is larger than the outer diameter of the second tubular portion 492 of the pressure member 49.

[Second insulating member]
The second insulating member 52 is a member that exhibits an annular shape as a whole. Like the first insulating member 51, the second insulating member 52 is made of a ceramic material such as alumina, which has insulating properties and high heat resistance. The second insulating member 52 is located inside the tip outer housing 31, inside the first inner housing 35, and outside the pressurizing member 49. Further, the second insulating member 52 is arranged on the rear end side of the first insulating member 51. Then, the surface on the front end side of the second insulating member 52 comes into contact with the surface on the rear end side of the third step portion 497 of the pressure member 49, and the surface on the rear end side of the second insulating member 52 is inside the second. It comes into contact with the surface of the housing 36 on the tip end side of the second tip cylindrical portion 361. The outer diameter of the second insulating member 52 is smaller than the inner diameter on the rear end side of the first inner step portion 354 of the first inner housing 35. Further, the inner diameter of the second insulating member 52 is larger than the outer diameter of the fourth tubular portion 494 of the pressure member 49. In this embodiment, the second insulating member 52 has the same dimensions as the first insulating member 51.

[Support member]
The support member 53 is a member having a hollow structure and having a cylindrical shape as a whole. The support member 53 is made of a metal material such as stainless steel, which has high conductivity and high heat resistance. The support member 53 is inside the tip outer housing 31, and the tip side thereof is arranged inside the pressurizing member 49. However, the rear end side of the support member 53 is in a state of protruding from the rear end of the pressure member 49. Then, the surface on the front end side of the support member 53 comes into contact with the surface on the rear end side of the rear end insulating member 45. Further, the boundary portion between the support member 53 and the pressurizing member 49 is laser welded over one circumference of the outer peripheral surface. Inside the support member 53, the rear end side of the first coil spring 46 and the tip end sides of the conduction member 47 and the holding member 48 are housed. The outer diameter of the support member 53 is slightly smaller than the inner diameter of the through hole provided in the pressure member 49. Further, the inner diameter of the through hole provided in the support member 53 is slightly larger than the outer diameter of the tip portion of the holding member 48.

[Second coil spring]
The second coil spring 54 is a member that exhibits a spiral shape as a whole, and is adapted to expand and contract in the center line direction. The second coil spring 54 is made of a metal material such as stainless steel, which has high conductivity and high heat resistance, and its surface is gold-plated. As described above, in the present embodiment, the materials of the first coil spring 46 and the second coil spring 54 are different. The second coil spring 54 is arranged inside the tip outer housing 31. More specifically, the tip end side of the second coil spring 54 is arranged on the rear end side of the support member 53 and outside the outer peripheral surface, and the tip end thereof is the fourth tubular portion 494 of the pressurizing member 49. It comes into contact with the surface on the rear end side. Inside the second coil spring 54, a conduction member 47, a holding member 48, a support member 53, and a tip end side of the first accommodating member 55 are arranged. The outer diameter of the second coil spring 54 is smaller than the inner diameter of the tip outer housing 31. Further, the inner diameter of the second coil spring 54 is larger than the outer diameter of the support member 53.

[First accommodating member]
FIG. 6A shows a perspective view of the first accommodating member 55 provided in the pressure detecting device 20. In FIG. 6A, the lower left side in the figure is the front end side, and the upper right side in the figure is the rear end side. Here, the first accommodating member 55 will be described with reference to FIG. 6A in addition to FIGS. 2 to 5.

The first accommodating member 55 is a member having a hollow structure and having a cylindrical shape as a whole. The first accommodating member 55 is made of a conductive metal material such as brass or stainless steel, and its surface is gold-plated.

The first accommodating member 55 is located on the rear end side of the first tip portion 551 located on the most tip side, the first intermediate portion 552 located on the rear end side of the first tip portion 551, and the first intermediate portion 552. It has a first rear end portion 553 and the like. In the first accommodating member 55, the outer diameter of the first intermediate portion 552 is larger than that of the first tip portion 551, and the first tip step portion 554 is formed at the boundary between the two. Further, the outer diameter of the first rear end portion 553 is larger than that of the first intermediate portion 552, and the first rear end step portion 555 is formed at the boundary between the two. The first accommodating member 55 is arranged inside the tip outer housing 31. More specifically, the tip end side of the first accommodating member 55, that is, the tip end side of the first tip end portion 551 faces the rear end side of the support member 53, and is on the outside of the outer peripheral surface of the first tip end portion 551. The second coil spring 54 is facing each other. The rear end of the second coil spring 54 abuts on the surface of the first accommodating member 55 on the tip end side of the first tip step portion 554. As a result, the second coil spring 54 is sandwiched between the pressurizing member 49 and the first accommodating member 55, so that the second coil spring 54 is compressed in the center line direction. The tips of the conducting member 47 and the holding member 48 are accommodated inside the through hole provided in the first accommodating member 55. The outer diameters of the first tip portion 551, the first intermediate portion 552, and the first rear end portion 553 in the first accommodating member 55 are smaller than the inner diameter of the tip outer housing 31. Further, the outer diameter of the first tip portion 551 is smaller than the inner diameter of the second coil spring 54, and the outer diameter of the first intermediate portion 552 is larger than the inner diameter of the second coil spring 54. Further, the inner diameter of the first accommodating member 55 is larger than the outer diameter of the holding member 48.

[Second accommodating member]
FIG. 6B shows a perspective view of the second accommodating member 56 provided in the pressure detecting device 20. In FIG. 6B, the lower left side in the figure is the front end side, and the upper right side in the figure is the rear end side. Here, the second accommodating member 56 will be described with reference to FIG. 6 (b) in addition to FIGS. 2 to 5.

The second accommodating member 56 is a member having a hollow structure and having a cylindrical shape as a whole. Like the first accommodating member 55, the second accommodating member 56 is made of a conductive metal material such as brass or stainless steel, and its surface is gold-plated.

The second accommodating member 56 is located on the rear end side of the second tip portion 561 located on the most tip side, the second intermediate portion 562 located on the rear end side of the second tip portion 561, and the second intermediate portion 562. It has a second rear end portion 563. In the second accommodating member 56, the outer diameter of the second intermediate portion 562 is larger than that of the second tip portion 561, and the second tip step portion 564 is formed at the boundary between the two. Further, the outer diameter of the second rear end portion 563 is larger than that of the second intermediate portion 562, and the second rear end step portion 565 is formed at the boundary between the two. Further, the second rear end portion 563 is formed with a circular round hole 566 (an example of a hole) penetrating the outer peripheral surface (an example of an outer surface) and the inner peripheral surface (an example of an inner surface). The second accommodating member 56 is arranged so as to straddle the inside of the tip outer housing 31 and the inside of the intermediate outer housing 33. More specifically, the tip end side of the second accommodating member 56, that is, the tip end side of the second tip portion 561 is accommodated in the first rear end portion 553 of the first accommodating member 55, and the second tip step portion. The front end side surface of 564 comes into contact with the rear end side surface of the first rear end portion 553. Further, an intermediate portion and a rear end portion of the holding member 48 are accommodated inside the through hole provided in the second accommodating member 56. The outer diameters of the second tip portion 561, the second intermediate portion 562, and the second rear end portion 563 of the second accommodating member 56 are smaller than the inner diameters of the tip outer housing 31 and the intermediate outer housing 33 facing each other. It has become. Further, the inner diameter of the second accommodating member 56 is larger than the outer diameter of the holding member 48. Further, the outer diameter of the second tip portion 561 of the second accommodating member 56 is slightly larger than the inner diameter of the first rear end portion 553 of the first accommodating member 55, and the first accommodating member 55 and the second accommodating member 55 and the second accommodating member 55. The member 56 is integrated with the member 56 by press fitting. The second accommodating member 56 may function alone as an accommodating member, or may function as an accommodating member together with the first accommodating member 55.

[Circuit built-in member]
As shown in FIG. 3, the circuit board built-in member 57 internally accommodates a circuit board 91 and a circuit board 91 that perform various processing using an electronic circuit on an electric signal due to a weak electric charge output by the piezoelectric element 41. Therefore, it is provided with a sealing portion 92 for sealing the circuit board 91. The circuit built-in member 57 is inside the intermediate outer housing 33, and almost the entire area except for a part on the rear end side is arranged inside the second accommodating member 56. Further, the tip end side of the circuit built-in member 57 is fitted into a recess provided on the rear end side of the holding member 48. A metal plate (details will be described later) provided on the tip end side of the circuit built-in member 57 comes into contact with the rear end side of the conduction member 47. Further, a metal plate (details will be described later) provided on the outer peripheral surface of the circuit built-in member 57 comes into contact with the inner peripheral surface of the second accommodating member 56. The details of the circuit built-in member 57 will be described later.

[Connecting member]
The connecting member 58 is a member that exhibits a columnar shape as a whole. The connecting member 58 includes a base material made of a synthetic resin material such as PPT having insulating properties, wiring and terminals made of a metal material such as copper having conductivity, and the like. The connecting member 58 is arranged so as to straddle the inside of the intermediate outer housing 33 and the inside of the rear end outer housing 34. The portion (outer peripheral surface) of the connecting member 58 facing the intermediate outer housing 33 or the rear end outer housing 34 is made of a synthetic resin material so that the metal material is not exposed to this portion. There is. The rear end side of the circuit built-in member 57 faces the front end side of the connection member 58, and the metal plate (details will be described later) provided in the circuit built-in member 57 is fitted into the terminal provided in the connection member 58. It is designed to be used. Further, on the rear end side of the connection member 58, each conductor portion exposed on the tip side of the power supply line 81, the signal line 82, and the ground line 83 (the details of which will be described later) constituting the connection cable 80 is inserted. ing. The outer diameter of the connecting member 58 is slightly larger than the inner diameter of the rear end side of the intermediate outer housing 33, and the intermediate outer housing 33 and the connecting member 58 are integrated by press fitting (tightening). There is.

[Blocking member]
The blocking member 59 is a member that exhibits a columnar shape as a whole. However, the closing member 59 is formed with three through holes along the center line direction. The closing member 59 is made of an insulating rubber material. The front end side of the closing member 59 is arranged inside the rear end outer housing 34, and the rear end side protrudes outside the rear end of the rear end outer housing 34. The tip end side of the closing member 59 faces the rear end side of the connecting member 58. Further, the power line 81, the signal line 82, and the grounding line 83 described above are inserted into the three through holes provided in the closing member 59. The outer diameter of the closing member 59 is slightly larger than the inner diameter of the rear end outer housing 34 on the rear end side, and the rear end outer housing 34 and the closing member 59 are integrated by press fitting. It has become.

[Third insulating member]
The third insulating member 60 is a member having a hollow structure and having a cylindrical shape as a whole. However, the third insulating member 60 has a structure in which a cylindrical portion provided on the front end side and a portion of the annular portion provided on the rear end side are integrated. The third insulating member 60 is made of a ceramic material such as alumina, which has insulating properties and high heat resistance. The third insulating member 60 is arranged so as to straddle the inside of the tip outer housing 31 and the inside of the intermediate outer housing 33. More specifically, the tip end side of the third insulating member 60 is arranged inside the tip outer housing 31, and the rear end side of the third insulating member 60 is arranged inside the intermediate outer housing 33. Has been done. The outer peripheral surface of the cylindrical portion of the third insulating member 60 faces the inner peripheral surface on the rear end side of the tip outer housing 31. Further, the surface on the tip end side of the annular portion of the third insulating member 60 comes into contact with the surface on the rear end side of the tip outer housing 31. On the other hand, the inner peripheral surface of the cylindrical portion of the third insulating member 60 is the outer peripheral surface of the first rear end portion 553 of the first accommodating member 55 and the outer peripheral surface of the second intermediate portion 562 of the second accommodating member 56. Is confronting. Further, the surface on the rear end side of the annular portion of the third insulating member 60 comes into contact with the surface on the tip end side of the second rear end step portion 565 of the second accommodating member 56. The outer diameter of the cylindrical portion of the third insulating member 60 is smaller than the inner diameter of the rear end side of the tip outer housing 31. Further, the outer diameter of the annular portion of the third insulating member 60 is smaller than the inner diameter on the tip end side of the intermediate outer housing 33. On the other hand, the inner diameter of the cylindrical portion of the third insulating member 60 is larger than the outer diameter of the first rear end portion 553 of the first accommodating member 55 and the outer diameter of the second intermediate portion 562 of the second accommodating member 56. ing. Further, the inner diameter of the annular portion of the third insulating member 60 is larger than the outer diameter of the second intermediate portion 562 of the second accommodating member 56.

(Structure of seal part)
As shown in FIGS. 2 and 3, the seal portion 70 includes a first seal member 71 relatively located on the front end side and a second seal member 72 relatively located on the rear end side. ..

[First seal member]
The first seal member 71 is a member that exhibits an annular shape as a whole, and in this example, it is composed of a square ring having a rectangular cross section. The first sealing member 71 is made of a synthetic resin material such as PTFE, which has insulating properties and high heat resistance and acid resistance. The first seal member 71 is attached to the outer peripheral surface of the tip outer housing 31 constituting the housing portion 30.

[Second seal member]
The second seal member 72 is a member that exhibits an annular shape as a whole, and in this example, it is composed of an O-ring having a circular cross section. The second seal member 72 is also made of a synthetic resin material such as PTFE, which has insulating properties and high heat resistance and acid resistance. The second seal member 72 is attached to the outer peripheral surface of the rear end outer housing 34 constituting the housing portion 30.

[Connection cable configuration]
The connection cable 80 includes a twisted power supply line 81, a signal line 82, and a ground wire 83, and a covering member (not shown) that covers the outer periphery of the power supply line 81, the signal line 82, and the ground wire 83. .. Here, the power supply line 81, the signal line 82, and the ground wire 83 are each made of a conductor portion made of tin-plated annealed copper stranded wire, silicon rubber, or the like, and are insulated by covering and insulating the outer periphery of the conductor portion. Has a part. Further, the covering member is made of a rubber material or a resin material having an insulating property. If necessary, the connection cable 80 may be provided with a shield that shields the power line 81, the signal line 82, and the ground line 83.

[Structure of circuit built-in member]
Next, the details of the circuit built-in member 57 described above will be described.
FIG. 7 is a perspective view of a circuit built-in member 57 provided in the pressure detection device 20. Further, FIG. 8 is a perspective view of the circuit built-in member 57 before the metal plate is bent (details will be described later). Further, FIG. 9 is a cross-sectional view of the circuit built-in member 57 (IX-IX cross-sectional view of FIG. 7). In FIGS. 7 and 8, the lower left side in the figure is the front end side, and the upper right side in the figure is the rear end side. Further, in FIG. 9, the left side in the figure is the front end side, and the right side in the figure is the rear end side.

As described above, the circuit built-in member 57 includes a circuit board 91 and a sealing portion 92. Further, the circuit built-in member 57 further includes an input signal plate 93, an input grounding plate 94, a power receiving plate 95, an output signal plate 96, and an output grounding plate 97.

(Circuit board)
FIG. 10 is a schematic configuration diagram of a circuit board 91 provided on the circuit built-in member 57. However, FIG. 10 also shows the connection relationship between the circuit board 91 and the input signal plate 93, the input grounding plate 94, the power receiving plate 95, the output signal plate 96, and the output grounding plate 97.

The circuit board 91 is a member having a rectangular plate shape as a whole. The circuit board 91 has a printed wiring board 911 on which a wiring pattern for mounting various electronic components (circuit elements) is formed, and a processing circuit 912 mounted on the printed wiring board 911.

In this embodiment, a so-called glass epoxy board based on a glass cloth base epoxy resin is used as the printed wiring board 911. The printed wiring board 911 is provided with an input signal terminal 91a, an input grounding terminal 91b, a power receiving terminal 91c, an output signal terminal 91d, and an output grounding terminal 91e as input / output terminals.

Here, a positive path (details will be described later) in the pressure detection device 20 is connected to the input signal terminal 91a via the input signal plate 93, and the input ground terminal 91b is connected to the input ground terminal 91b via the input ground plate 94. , Negative paths in the pressure detector 20 (details below) are connected. On the other hand, the power supply line 81 is connected to the power receiving terminal 91c via the power receiving plate 95, the signal line 82 is connected to the output signal terminal 91d via the output signal plate 96, and the output ground terminal 91e is connected to the power line 82. , The ground wire 83 is connected via the output ground plate 97. In the printed wiring board 911, the input ground terminal 91b and the output ground terminal 91e are internally connected.

Further, the processing circuit 912 includes an amplifier circuit 912a that integrates the charge signal input from the piezoelectric element 41 via the input signal terminal 91a and converts it into a voltage signal, and an output signal terminal that amplifies the converted voltage signal. It has an amplifier circuit 912b that outputs to 91d. Here, the integrator circuit 912a and the amplifier circuit 912b are supplied with a power supply voltage for operating them via the power receiving terminal 91c. Further, the ground of the integrator circuit 912a and the amplifier circuit 912b is connected to the input ground terminal 91b and the output ground terminal 91e. In this example, the processing circuit 912 is composed of a so-called integrated circuit (IC).

(Sealing part)
The sealing portion 92 is a member having a columnar shape as a whole. The sealing portion 92 is made of a synthetic resin material such as epoxy having an insulating property. The sealing portion 92 includes a small diameter portion 921 located on the most advanced side, a medium diameter portion 922 located on the rear end side of the small diameter portion 921, and a large diameter portion 923 located on the rear end side of the medium diameter portion 922. I have. In the sealing portion 92, the outer diameter increases in the order of the small diameter portion 921, the medium diameter portion 922, and the large diameter portion 923. Further, the small diameter portion 921, the medium diameter portion 922, and the large diameter portion 923 each have a polygonal (for example, octagonal) cross-sectional shape. Here, in the present embodiment, the circuit board 91 is housed inside the medium diameter portion 922 of the sealing portion 92.

Further, the medium diameter portion 922 is provided with a front surface 922a and a back surface 922b located on the back side of the front surface 922a. Here, the front surface 922a and the back surface 922b have a positional relationship substantially parallel to the front surface and the back surface of the printed wiring board 911 in the circuit board 91. Then, on the rear end side of the surface 922a, a surface protrusion group 924 formed by connecting a plurality of protrusions is provided. On the other hand, a back surface protrusion group 925 formed by connecting a plurality of protrusions is also provided on the rear end side of the back surface 922b. The surface protrusion group 924 includes a surface first protrusion 924a (an example of the protrusion) and a surface second protrusion 924b located on the rear end side of the surface first protrusion 924a. Further, the back surface projection group 925 includes a back surface first projection 925a (an example of another projection) and a back surface second projection 925b located on the rear end side of the back surface first projection 925a. Here, the back surface first projection 925a is located on the back side of the front surface first projection 924a, and the back surface second projection 925b is located on the back side of the front surface second projection 924b. The front surface first projection 924a, the front surface second projection 924b, the back surface first projection 925a, and the back surface second projection 925b each have an inclined surface that is inclined so as to increase the outer diameter from the front end side to the rear end side. On the rear end side of the inclined surface, it has a shape in which a flat surface having a constant outer diameter is connected from the front end side to the rear end side. Here, the heights of the front surface first projection 924a and the front surface second projection 924b with respect to the front surface 922a and the heights of the back surface first projection 925a and the back surface second projection 925b with respect to the back surface 922b are set to be the same size. .. The size of the outer diameter from the front surface second protrusion 924b to the back surface second protrusion 925b in the middle diameter portion 922 is smaller than the outer diameter of the large diameter portion 923. Further, the size of each outer diameter on the tip side in the small diameter portion 921 and the middle diameter portion 922 is smaller than the size of the inner diameter of the second rear end portion 563 in the second accommodating member 56. Further, the size of the outer diameter from the front surface first protrusion 924a to the back surface first protrusion 925a in the middle diameter portion 922 is also smaller than the size of the inner diameter of the second rear end portion 563. On the other hand, the size of the outer diameter of the large diameter portion 923 is slightly larger than the size of the inner diameter of the second rear end portion 563.

(Input signal board)
The input signal plate 93 is a member having a plate shape (strip shape) as a whole. The input signal plate 93 is made of a metallic material such as brass having conductivity and elasticity, and its surface is gold-plated. The input signal plate 93 is arranged so as to project from the front end side surface of the small diameter portion 921 of the sealing portion 92 toward the tip end side. However, the rear end side of the input signal plate 93 is arranged inside the sealing portion 92 and is fixed by using the sealing portion 92. The tip end side of the input signal plate 93 is bent so as to face upward in FIG. 7. The input signal plate 93 comes into contact with the rear end side of the conduction member 47.

(Input ground plate)
The input ground plate 94 as an example of the conductive portion is a member having a plate shape (F shape) as a whole. The input ground plate 94 is also made of a metallic material such as brass having conductivity and elasticity, and its surface is gold-plated. The input ground plate 94 includes a first protruding portion 941 and a second protruding portion 942, which are provided so as to project laterally from the outer peripheral surface (other than the front surface 922a and the back surface 922b) of the medium diameter portion 922 in the sealing portion 92, respectively. It includes a first protruding portion 941 and a main body portion 943 connected to the second protruding portion 942. However, one end side of each of the first protruding portion 941 and the second protruding portion 942 is arranged inside the sealing portion 92 and is fixed by using the sealing portion 92. Here, the second protruding portion 942 is arranged on the rear end side of the first protruding portion 941. Further, the main body portion 943 has a strip-shaped shape extending from the front end side toward the rear end side. The first protruding portion 941 and the second protruding portion 942 are bent upward in FIG. 7 along the shape of the outer peripheral surface of the medium diameter portion 922, and the main body portion 943 is provided on the surface 922a. It is designed to confront the surface protrusion group 924. Here, the size of the outer diameter in which the thickness of the main body portion 943 in the input ground plate 94 is added to the outer diameter from the front surface first protrusion 924a to the back surface first protrusion 925a in the middle diameter portion 922 is the second accommodating member. It is slightly larger than the size of the inner diameter of the second rear end portion 563 in 56. Further, in this example, in the processing circuit 912 shown in FIG. 10, the grounding system related to the power supply and the grounding system related to the signal are actually separated, and the grounding system related to the power supply is connected to the first protrusion 941 for a signal. The grounding system is connected to the second protrusion 942, respectively. The main body 943 of the input ground plate 94 comes into contact with the inner peripheral surface of the second accommodating member 56.

(Power receiving plate)
The power receiving plate 95 is a member having a plate shape (strip shape) as a whole. The power receiving plate 95 is also made of a metallic material such as brass having conductivity and elasticity, and its surface is gold-plated. The power receiving plate 95 is arranged so as to project from the surface of the sealing portion 92 on the rear end side of the large diameter portion 923 toward the rear end side. However, the tip end side of the power receiving plate 95 is arranged inside the sealing portion 92 and is fixed by using the sealing portion 92. The rear end side of the power receiving plate 95 is bent so as to face upward in FIG. 7. The power receiving plate 95 is connected to the power supply line 81 via the connecting member 58.

(Output signal board)
The output signal plate 96 is a member having a plate shape (strip shape) as a whole. The output signal plate 96 is also made of a metallic material such as brass having conductivity and elasticity, and its surface is gold-plated. The output signal plate 96 is arranged so as to project from the surface of the sealing portion 92 on the rear end side of the large diameter portion 923 toward the rear end side. However, the tip end side of the output signal plate 96 is arranged inside the sealing portion 92 and is fixed by using the sealing portion 92. Further, the output signal plate 96 is arranged adjacent to the power receiving plate 95. The rear end side of the output signal plate 96 is bent so as to face downward in FIG. 7. The output signal plate 96 is connected to the signal line 82 via the connecting member 58.

(Output ground plate)
The output ground plate 97 is a member having a plate shape (strip shape) as a whole. The output ground plate 97 is also made of a metallic material such as brass having conductivity and elasticity, and its surface is gold-plated. The output ground plate 97 is arranged so as to project from the surface of the sealing portion 92 on the rear end side of the large diameter portion 923 toward the rear end side. However, the tip end side of the output ground plate 97 is arranged inside the sealing portion 92 and is fixed by using the sealing portion 92. Further, the output ground plate 97 is arranged adjacent to the output signal plate 96. The rear end side of the output ground plate 97 is bent so as to face upward in FIG. 7. The output grounding plate 97 is connected to the grounding wire 83 via the connecting member 58.

[Electrical connection structure in pressure detector]
Here, the electrical connection structure of the pressure detection device 20 will be described.
(Positive route)
In the pressure detection device 20, the end face (positive electrode: an example of one pole) on the rear end side of the piezoelectric element 41 is electrically connected to the rear end electrode member 44, the first coil spring 46, and the conduction member 47. Further, the conduction member 47 is electrically connected to the input signal plate 93 provided in the circuit built-in member 57. Then, the input signal board 93 is electrically connected to the input signal terminal 91a of the circuit board 91 provided in the same circuit built-in member 57. In the following, the electrical electrical from the rear end side surface of the piezoelectric element 41 to the input signal terminal 91a of the circuit board 91 via the rear end electrode member 44, the first coil spring 46, the conduction member 47, and the input signal plate 93. The route is referred to as a "positive route".

(Negative route)
On the other hand, in the pressure detection device 20, the end face (negative electrode: an example of the other pole) on the tip end side of the piezoelectric element 41 is electrically connected to the tip electrode member 42, the pressurizing member 49, and the support member 53. Further, the pressurizing member 49 is electrically connected to the input ground plate 94 provided on the second coil spring 54, the first accommodating member 55, the second accommodating member 56, and the circuit built-in member 57. Then, the input grounding plate 94 is electrically connected to the input grounding terminal 91b of the circuit board 91 provided in the same circuit built-in member 57. In the following, from the front end side surface of the piezoelectric element 41, the tip electrode member 42, the pressurizing member 49, the support member 53, the second coil spring 54, the first accommodating member 55, the second accommodating member 56, and the input grounding plate 94 are interposed. The electrical path leading to the input ground terminal 91b of the circuit board 91 is referred to as a "negative path".

(Case route)
On the other hand, in the pressure detecting device 20, the diaphragm head 32 is electrically connected to the front end outer housing 31, the intermediate outer housing 33, and the rear end outer housing 34. Further, the diaphragm head 32 is electrically connected to the first internal housing 35 and the second internal housing 36. In the following, the electrical path from the second inner housing 36 to the first inner housing 35, the diaphragm head 32, the tip outer housing 31, the intermediate outer housing 33, and the rear end outer housing 34 will be referred to as “housing”. It is called "body pathway". When the pressure detecting device 20 is attached to the cylinder head 13 of the internal combustion engine 10 shown in FIG. 1, for example, the tip outer housing 31 comes into contact with the inner peripheral surface of the communication hole 13a. At this time, the cylinder head 13 (and the cylinder block 11) and the housing path have substantially the same potential.

(Relationship between positive and negative paths)
Here, in the pressure detection device 20 of the present embodiment, a negative path exists outside the positive path. In other words, the positive path is contained inside the negative path. The positive path and the negative path are electrically insulated by the rear end insulating member 45, the holding member 48, the insulating pipe 50, and the air gap formed between the two paths.

(Relationship between negative route and housing route)
Further, in the pressure detecting device 20, the housing path exists outside the negative path. In other words, a negative path is housed inside the housing path. The negative path and the housing path are electrically connected by the tip insulating member 43, the first insulating member 51, the second insulating member 52, the third insulating member 60, and the air gap formed between both paths. It is insulated.

(Relationship between chassis path and positive path)
Further, in the pressure detection device 20, as a result, the housing path exists outside the positive path. In other words, the positive path is housed inside the housing path. Then, as described above, the positive path and the negative path are electrically isolated, and the negative path and the housing path are electrically insulated, so that the housing path and the positive path are obtained. However, it is electrically isolated.

[Manufacturing procedure for circuit built-in parts]
Then, the manufacturing procedure of the circuit built-in member 57 will be described with reference to FIGS. 7 to 9.
First, the input signal plate 93, the input grounding plate 94, the power receiving plate 95, the output signal plate 96, and the output grounding plate 97 are positioned and connected to the circuit board 91 to obtain a connector.

Next, the connection body is set in the transfer mold device, and the transfer mold is performed with an insulating synthetic resin material (here, epoxy resin) to form the sealing portion 92, and then from the transfer mold device. Take it out. The circuit built-in member 57 taken out from the transfer mold device is in the state shown in FIG. 8, and each end of the input signal plate 93, the input grounding plate 94, the power receiving plate 95, the output signal plate 96, and the output grounding plate 97. However, it protrudes from the sealing portion 92 in a flat state.

Subsequently, among the circuit built-in members 57 shown in FIG. 8, for each of the input signal plate 93, the input grounding plate 94, the power receiving plate 95, the output signal plate 96, and the output grounding plate 97 protruding from the sealing portion 92. Bend it. As a result, the circuit built-in member 57 shown in FIG. 7 and the like can be obtained.

[Manufacturing procedure of pressure detector]
Subsequently, the manufacturing procedure of the pressure detecting device 20 described above will be described with reference to FIGS. 2 to 10.
(Assembly of the first structure)
First, the insulating pipe 50 is inserted from the rear end side into the pressurizing member 49 having the first tubular portion 491 as the front end side and the fourth tubular portion 494 as the rear end side. At this time, the surface on the tip end side of the insulating pipe 50 abuts on the surface on the rear end side of the fourth step portion 498 provided inside the pressurizing member 49. As a result, the outer peripheral surface of the insulating pipe 50 faces the inner peripheral surface of the pressurizing member 49.

Next, the front end electrode member 42, the piezoelectric element 41, the rear end electrode member 44, and the rear end insulating member 45 are inserted into the pressure member 49 in this order from the rear end side. At this time, the surface on the tip end side of the tip electrode member 42 abuts on the surface on the rear end side of the fourth step portion 498 provided inside the pressurizing member 49. Further, the front end side surface of the piezoelectric element 41 is on the rear end side surface of the front end electrode member 42, and the front end side surface of the rear end electrode member 44 is on the rear end side surface of the piezoelectric element 41. The front end side surface of the rear end insulating member 45 abuts on the rear end side surface of the member 44, respectively. As a result, the outer peripheral surfaces of the front end electrode member 42, the piezoelectric element 41, the rear end electrode member 44, and the rear end insulating member 45 face each other with the inner peripheral surface of the insulating pipe 50.

Subsequently, the support member 53 is inserted into the pressure member 49 from the rear end side. At this time, the surface on the front end side of the support member 53 abuts on the surface on the rear end side of the rear end insulating member 45. As a result, the outer peripheral surface on the tip end side of the support member 53 faces the inner peripheral surface of the pressure member 49. Further, the rear end side of the support member 53 protrudes to the outside (rear end side) from the rear end of the pressure member 49.

Next, by moving (advancing / retreating) the support member 53 with respect to the pressurizing member 49 along the direction of the center line, the load applied to the piezoelectric element 41 via each member is adjusted. Then, with the load adjusted, laser welding is performed on the boundary portion between the pressure member 49 and the support member 53 over one circumference to obtain a first structure.

(Assembly of the second structure)
Further, in a process different from the manufacturing of the first structure, the back surface of the diaphragm head 32, that is, the rear end side, and the front end side of the first internal housing 35 are opposed to each other. Subsequently, the front end side surface of the first outer step portion 353 of the first inner housing 35 is abutted against the rear end side surface of the back surface annular convex portion 32f of the diaphragm head 32. Along with this, the first tip cylindrical portion 351 of the first internal housing 35 is arranged in the back surface annular recess 32c of the diaphragm head 32. Then, in this state, the second structure is obtained by performing laser welding on the boundary portion between the diaphragm head 32 and the first internal housing 35 over one circumference.

(Assembly of the third structure)
Next, the tip insulating member 43 is inserted into the first internal housing 35 of the second structure from the rear end side. At this time, the surface on the tip side of the tip insulating member 43 abuts on the surface on the rear end side of the back surface center convex portion 32d of the diaphragm head 32.

Subsequently, the first insulating member 51 is inserted into the first internal housing 35 of the second structure from the rear end side. At this time, the surface on the tip end side of the first insulating member 51 abuts on the surface on the rear end side of the first inner step portion 354 in the first inner housing 35. As a result, the outer peripheral surface of the first insulating member 51 faces the inner peripheral surface on the rear end side of the first inner housing 35.

Next, the first structure is inserted into the first internal housing 35 of the second structure from the rear end side with the tip electrode member 42 as the tip side. At this time, the surface on the tip end side of the tip electrode member 42 abuts on the surface on the rear end side of the tip insulating member 43, and the second step in the pressurizing member 49 hits the surface on the rear end side of the first insulating member 51. The surface on the tip side of the portion 496 abuts. As a result, the outer peripheral surface of the second tubular portion 492 of the pressure member 49 faces the inner peripheral surface of the first insulating member 51. At this time, an air gap is formed between the outer peripheral surface of the pressure member 49 on the distal end side (first tubular portion 491 side) and the inner peripheral surface of the diaphragm head 32 and the first internal housing 35. Will be done. Further, at this time, an air gap is also formed between the surface on the tip end side of the first step portion 495 in the pressurizing member 49 and the surface on the rear end side of the first inner step portion 354 in the first inner housing 35. It is formed. Further, at this time, an air gap is also formed between the outer peripheral surface of the third tubular portion 493 of the pressurizing member 49 and the inner peripheral surface of the first inner housing 35. Furthermore, at this time, the rear end side of the fourth cylindrical portion 494 of the pressurizing member 49 protrudes to the outside (rear end side) from the rear end of the first inner housing 35.

Then, the second insulating member 52 is inserted into the first internal housing 35 of the second structure from the rear end side. At this time, the surface on the tip end side of the second insulating member 52 abuts on the surface on the rear end side of the third step portion 497 in the pressure member 49. As a result, the inner peripheral surface of the second insulating member 52 faces the outer peripheral surface of the fourth tubular portion 494 of the pressure member 49. Further, the outer peripheral surface of the second insulating member 52 faces the inner peripheral surface of the first inner housing 35.

Next, the second inner housing 36 is inserted into the first inner housing 35 of the second structure from the rear end side with the second tip cylindrical portion 361 as the tip side. At this time, the surface on the tip side of the second tip cylindrical portion 361 in the second inner housing 36 abuts on the surface on the rear end side of the second insulating member 52. As a result, the inner peripheral surface of the second inner housing 36 faces the outer peripheral surface of the fourth cylindrical portion 494 of the pressurizing member 49 via the air gap. Further, the outer peripheral surface on the front end side of the second inner housing 36 faces the inner peripheral surface on the rear end side of the first inner housing 35. Further, the second rear end cylindrical portion 362 of the second inner housing 36 protrudes to the outside (rear end side) from the rear end of the first inner housing 35. As a result, the surface on the tip end side of the second outer step portion 363 in the second inner housing 36 is the surface on the rear end side of the first rear end cylindrical portion 352 in the first inner housing 35 via the air gap. Face each other.

Subsequently, the second internal housing 36 is moved (advanced and retreated) along the center line direction with respect to the first internal housing 35 to adjust the load applied to the piezoelectric element 41 via each member. Then, with the load adjusted, laser welding is performed on the boundary between the first internal housing 35 and the second internal housing 36 over one circumference to obtain a third structure.

(Assembly of the 4th structure)
Next, the tip outer housing 31 is inserted into the third structure from the rear end side. At this time, the front end side surface of the front end outer housing 31 abuts on the rear end side surface of the back surface annular flat portion 32e of the diaphragm head 32. At this time, each component other than the diaphragm head 32 in the third structure is housed inside the tip outer housing 31. Further, at this time, the diaphragm head 32 constituting the third structure is exposed to the outside together with the tip outer housing 31 with the pressure receiving surface 32a and the surface center recess 32b facing outward. Then, in this state, the fourth structure is obtained by performing laser welding on the boundary portion between the tip outer housing 31 and the diaphragm head 32 over one circumference.

(Assembly of the 5th structure)
Further, in a process different from the manufacturing of the fourth structure, the conduction member 47 is inserted into the holding member 48 from the rear end side with the tip rod-shaped portion 471 as the tip side. At this time, the tip rod-shaped portion 471 and the intermediate rod-shaped portion 472 of the conduction member 47 and the tip end side of the rear end rod-shaped portion 473 are made to protrude toward the tip end side of the holding member 48. As a result, the rear end side of the rear end rod-shaped portion 473 of the conduction member 47 faces the inner peripheral surface of the holding member 48. Subsequently, the circuit built-in member 57 is fitted into the recess provided on the rear end side of the holding member 48 from the rear end side with the small diameter portion 921 of the sealing portion 92 as the tip end side to obtain a fifth structure. .. At this time, the input signal plate 93 provided in the circuit built-in member 57 comes into contact with the rear end of the rear end rod-shaped portion 473 of the conduction member 47.

(Assembly of the 6th structure)
Next, the third insulating member 60 is inserted into the front end outer housing 31 of the fourth structure from the rear end side. At this time, the surface on the tip end side of the portion of the annular portion provided on the rear end side of the third insulating member 60 abuts on the surface on the rear end side of the tip outer housing 31. As a result, the outer peripheral surface of the cylindrical portion provided on the tip end side of the third insulating member 60 faces the inner peripheral surface of the tip outer housing 31.

Subsequently, the second coil spring 54 is inserted into the tip outer housing 31 of the fourth structure from the rear end side, and the first accommodating member 55 is inserted with the first tip portion 551 as the tip side. At this time, the tip of the second coil spring 54 abuts on the surface of the pressurizing member 49 on the rear end side of the fourth tubular portion 494. Further, the first tip portion 551 of the first accommodating member 55 is housed inside the rear end side of the second coil spring 54, and the rear end of the second coil spring 54 is housed on the tip end side surface of the first tip step portion 554. bump into. Along with this, the second coil spring 54 is compressed in the center line direction. Further, as a result, the outer peripheral surfaces of the second coil spring 54 and the first accommodating member 55 face the inner peripheral surface of the tip outer housing 31 via the air gap. However, the outer peripheral surface of the first rear end portion 553 of the first accommodating member 55 faces the inner peripheral surface of the tip outer housing 31 via the third insulating member 60.

Next, the second accommodating member 56 is inserted into the tip outer housing 31 of the fourth structure from the rear end side with the second tip portion 561 as the tip side. At this time, the second tip portion 561 located on the tip end side of the second housing member 56 fits inside the first rear end portion 553 provided on the rear end side of the first housing member 55. Further, at this time, the surface on the tip end side of the second rear end step portion 565 of the second accommodating member 56 abuts on the surface on the rear end side of the annular portion of the third insulating member 60. As a result, the outer peripheral surface of the second intermediate portion 562 of the second accommodating member 56 faces the inner peripheral surface of the cylindrical portion portion of the third insulating member 60.

Next, the first coil spring 46 is inserted into the tip outer housing 31 of the fourth structure from the rear end side. At this time, the tip of the first coil spring 46 abuts on the rear end side surface of the rear end electrode member 44 via the through hole provided in the rear end insulating member 45.

Subsequently, the fifth structure is inserted into the tip outer housing 31 of the fourth structure from the rear end side with the tip rod-shaped portion 471 of the conduction member 47 as the tip side.

At this time, the conduction member 47 exposed on the tip end side of the fifth structure is housed in the support member 53. However, the tip rod-shaped portion 471 of the conduction member 47 protrudes toward the tip side of the support member 53 and is accommodated in the first coil spring 46. At this time, the surface on the tip end side of the stepped portion between the tip rod-shaped portion 471 and the intermediate rod-shaped portion 472 provided on the conduction member 47 abuts on the rear end of the first coil spring 46. Along with this, the first coil spring 46 is compressed in the center line direction. As a result, the tip end side of the conduction member 47 faces the support member 53 via the air gap.

Further, the holding member 48 located on the intermediate side of the fifth structure is accommodated straddling the support member 53, the first accommodating member 55, and the second accommodating member 56. At this time, one step portion provided on the holding member 48 abuts on the step provided on the back side of the first rear end step portion 555 in the first accommodating member 55, and is provided on the rear end side of the step portion. The other step portion abuts on the step provided on the back side of the second rear end step portion 565 of the second accommodating member 56. As a result, the outer peripheral surface of the holding member 48 faces the inner peripheral surfaces of the support member 53, the first accommodating member 55, and the second accommodating member 56.

Further, in the circuit built-in member 57 located on the rear end side of the fifth structure, the small diameter portion 921 and the medium diameter portion 922 of the sealing portion 92 are accommodated in the second accommodating member 56, while the large diameter portion 922 is on the rearmost end side. The diameter portion 923 protrudes to the outside (rear end side) from the rear end of the second accommodating member 56.

Here, the procedure for attaching the circuit built-in member 57 to the second accommodating member 56 will be described more specifically.
When the fifth structure is inserted into the fourth structure, the circuit built-in member 57 is inserted or pushed into the second accommodating member 56 from the rear end side with the small diameter portion 921 as the front end side. At this time, the circuit built-in member 57 is accommodated inside the second rear end portion 563 of the second accommodating member 56 in the order of the small diameter portion 921 and the medium diameter portion 922. Further, the input ground plate 94 attached to the outer peripheral surface of the middle diameter portion 922 of the circuit built-in member 57 is also housed inside the second rear end portion 563 together with the middle diameter portion 922.

Then, the outer peripheral surface of the holding member 48 constituting the fifth structure together with the circuit built-in member 57 abuts on the inner peripheral surface of the second accommodating member 56 as described above, so that the circuit is built into the second accommodating member 56. The member 57 cannot be pushed in any further. At this time, the small diameter portion 921 and the medium diameter portion 922 (including the input grounding plate 94) of the circuit built-in member 57 are housed inside the second rear end portion 563 of the second accommodating member 56, while the large diameter portion 923. Pops out to the outside (rear end side) of the rear end of the second rear end portion 563. However, each rearmost end portion of the middle diameter portion 922 and the main body portion 943 may slightly protrude to the outside (rear end side) from the rear end portion of the second rear end portion 563.

When the circuit built-in member 57 is inserted into the second accommodating member 56, the main body portion 943 of the input ground plate 94 has a surface first projection 924a and a surface first protrusion 924a provided on the surface 922a of the medium diameter portion 922 located behind the main body portion 943. The shape of the surface second protrusion 924b (inclined surface on the tip side and flat surface on the rear end side of each) guides the surface smoothly. Further, when the circuit built-in member 57 is inserted into the second accommodating member 56, the back surface first projection 925a and the back surface second projection 925b provided on the back surface 922b of the medium diameter portion 922 also have their shapes (each tip side). The inclined surface and the flat surface on the rear end side) make it difficult to prevent the insertion of the circuit built-in member 57.

Further, when the circuit built-in member 57 is inserted into the second accommodating member 56, the input ground plate 94 having an F-shaped shape is pulled toward the rear end side due to friction with the second accommodating member 56. At this time, the rear end of the main body portion 943 provided on the input ground plate 94 abuts on the step formed between the medium diameter portion 922 and the large diameter portion 923 so as not to be pulled further toward the rear end side. It has become. The surface second protrusion 924b provided on the medium diameter portion 922 is the rear end of the main body portion 943 provided on the input ground plate 94 with respect to the step formed between the medium diameter portion 922 and the large diameter portion 923. Assists in the thrusting. As a result, when the circuit built-in member 57 is inserted into the second accommodating member 56, the main body portion 913 of the input ground plate 94 is twisted by contact with the inner peripheral surface of the second accommodating member 56, and the first protruding portion is formed. The input ground plate 94 is suppressed from being cut by the 941 or the second protruding portion 942.

In a state where the input ground plate 94 constituting the circuit built-in member 57 is housed in the second rear end portion 563 of the second housing member 56, the surface protrusion group 924 provided on the surface 922a of the medium diameter portion 922 is input. The main body portion 943 of the ground plate 94 is pushed toward the inner peripheral surface of the second rear end portion 563 of the second accommodating member 56. At this time, the back surface protrusion group 925 provided directly behind the front surface protrusion group 924, that is, the back surface protrusion group 922b, abuts on the inner peripheral surface of the second rear end portion 563 of the second accommodating member 56, and the surface protrusion group 924 causes a second. 2 The main body portion 943 is pressed against the inner peripheral surface of the second rear end portion 563 of the accommodating member 56. Further, the first projecting portion 941 and the second projecting portion 942 constituting the input grounding plate 94 together with the main body portion 943 themselves function as leaf springs, so that the main body portion 943 is used as the second housing member 56. Push toward the inner peripheral surface of the rear end portion 563. Further, the size of the outer diameter obtained by adding the thickness of the main body portion 943 of the input ground plate 94 to the outer diameter from the front surface first protrusion 924a to the back surface first protrusion 925a in the middle diameter portion 922 is the second accommodating member 56. It is slightly larger than the size of the inner diameter of the inner peripheral surface of the second rear end portion 563 in. Therefore, the outer peripheral surface of the main body portion 943 of the input grounding plate 94 provided in the circuit built-in member 57 is pressed against the inner peripheral surface of the second rear end portion 563 of the second accommodating member 56 with a certain pressure. It will come into contact in the state.

Further, the main body portion 943 provided in the input grounding plate 94 with the medium diameter portion 922 of the circuit built-in member 57 and the input grounding plate 94 accommodated inside the second rear end portion 563 of the second accommodating member 56. Confronts the round hole 566 provided in the second rear end portion 563. That is, the round hole 566 provided in the second rear end portion 563 of the second accommodating member 56 and the main body portion 943 provided in the input grounding plate 94 of the circuit built-in member 57 are overlapped with each other. In other words, the main body portion 943 provided in the input grounding plate 94 of the circuit built-in member 57 can be seen from the round hole 566 provided in the second rear end portion 563 of the second accommodating member 56. At this time, the flat surface of the surface first protrusion 924a provided on the surface 922a of the medium diameter portion 922 is located behind the portion of the main body portion 943 that can be seen from the round hole 566. Further, behind the flat surface of the front surface first protrusion 924a, the flat surface of the back surface first protrusion 925a provided on the back surface 922b of the medium diameter portion 922 is located. As a result, the portion of the main body portion 943 that can be seen from the round hole 566 has a higher pressure than the portion that cannot be seen from the round hole 566, and the inner peripheral surface of the second rear end portion 563 of the second accommodating member 56. Will be pressed against.

Then, in this state, at the forming portion of the round hole 566, the second rear end portion 563 of the second accommodating member 56 (more specifically, the inner peripheral surface of the round hole 566) is formed through the round hole 566. , The sixth structure is obtained by soldering the main body portion 943 of the input ground plate 94. At this time, the surface first projection 924a provided on the medium diameter portion 922 of the circuit built-in member 57 has the input ground plate 94 on the back side (sealing portion) when the input ground plate 94 is pushed by a soldering iron or the like. By pulling it to the 92 side), it is possible to prevent soldering from being hindered. In the case where the rearmost end portion of the main body portion 943 of the input grounding plate 94 slightly protrudes to the outside (rear end side) of the rear end portion of the second rear end portion 563 of the second accommodating member 56. In this portion, the second accommodating member 56 and the main body portion 943 of the input grounding plate 94 may be further soldered. Here, the reason why the second accommodating member 56 and the input ground plate 94 of the circuit built-in member 57 are joined (soldered) is that the mounting target of the pressure detection device 20 vibrates with the operation of the internal combustion engine 10. It is due to the fact that.

(Assembly of the 7th structure)
Next, the intermediate outer housing 33 is inserted into the front end outer housing 31 of the sixth structure from the rear end side. At this time, the front end side surface of the intermediate outer housing 33 abuts on the rear end side surface of the front end outer housing 31. Then, a seventh structure is obtained by performing laser welding on the boundary portion between the tip outer housing 31 and the intermediate outer housing 33 over one circumference.

(Assembly of the 8th structure)
Although detailed description is omitted here, the connection and connection of the rear end external housing 34, the connecting member 58, the closing member 59, the second seal member 72, and the connecting cable 80 (power line 81, signal line 82, and grounding line 83) and Assemble to obtain the eighth structure.

(Assembly of 9th structure)
The ninth structure is obtained by inserting the eighth structure into the intermediate outer housing 33 of the seventh structure from the rear end side. At this time, the rear end side of the intermediate outer housing 33 is housed in the front end side of the rear end outer housing 34. Further, at this time, the power receiving plate 95 provided in the circuit built-in member 57 is inserted into the terminal connected to the power supply line 81 in the connecting member 58, and the terminal connected to the signal line 82 in the connecting member 58. Is inserted into the output signal plate 96 provided in the circuit built-in member 57, and the output grounding plate 97 provided in the circuit built-in member 57 is inserted into the terminal connected to the ground wire 83 in the connecting member 58. ..

(Assembly of pressure detector)
Finally, the first seal member 71 is inserted into the tip outer housing 31 of the ninth structure from the tip side. At this time, the surface on the rear end side of the first seal member 71 abuts on the surface on the front end side of the step portion provided on the rear end side of the front end outer housing 31. As a result, the inner peripheral surface of the first seal member 71 faces the outer peripheral surface of the tip outer housing 31.
From the above, the pressure detection device 20 integrated with the connection cable 80 can be obtained.

[Pressure detection operation by pressure detector]
Then, the pressure detection operation by the pressure detection device 20 will be described.
When the internal combustion engine 10 is operating, the pressure (combustion pressure) generated in the combustion chamber C is applied to the pressure receiving surface 32a of the diaphragm head 32. In the diaphragm head 32, the pressure received by the pressure receiving surface 32a is transmitted to the back surface central convex portion 32d on the back side, and further transmitted from the back surface center convex portion 32d to the tip electrode member 42 via the tip insulating member 43. Then, the pressure transmitted to the front end electrode member 42 acts on the piezoelectric element 41 sandwiched between the front end electrode member 42 and the rear end electrode member 44, and the piezoelectric element 41 generates an electric charge according to the received pressure. The electric charge generated in the piezoelectric element 41 is supplied as an electric charge signal to the input signal terminal 91a and the input ground terminal 91b of the circuit board 91 via a positive path and a negative path. The charge signal supplied to the circuit board 91 becomes an output signal by being subjected to various processes by the processing circuit 912 mounted on the circuit board 91. Then, the output signal output from the output signal terminal 91d of the circuit board 91 is transmitted to the control device 100 via the connection member 58 and the connection cable 80.

[Effect of this embodiment]
In the pressure detection device 20 of the present embodiment, the circuit board 91 including the processing circuit 912 connected to the positive electrode side of the piezoelectric element 41 is built in the sealing portion 92 and is sealed. Was used. Further, an input grounding plate 94 for connecting to the negative electrode side of the piezoelectric element 41 is provided on the side surface of the sealing portion 92 of the circuit built-in member 57. Then, as the circuit built-in member 57 is inserted into the tubular second accommodating member 56 connected to the negative electrode side of the piezoelectric element 41, the circuit built-in member 57 is placed on the inner peripheral surface of the second accommodating member 56. The input ground plate 94 provided on the outer peripheral surface is abutted against the input ground plate 94. Thereby, for example, even when an impact is applied to the pressure detecting device 20 from the outside, the separation between the second accommodating member 56 and the input grounding plate 94 can be suppressed. Therefore, the reliability of the electrical connection between the piezoelectric element 41 and the processing circuit 912 in the pressure detection device 20 can be improved.

Further, in the present embodiment, the input ground plate 94 is connected to the first protruding portion 941 and the second protruding portion 942 protruding from the side surface of the sealing portion 92, and the first protruding portion 941 and the second protruding portion 942. It was composed of a main body portion 943. Then, the first protruding portion 941 and the second protruding portion 942 are bent along the outer peripheral surface of the sealing portion 92. As a result, the first protruding portion 941 and the second protruding portion 942 function as leaf springs, and the inner circumference of the second accommodating member 56 is compared with the case where the input ground plate 94 does not have the function of a leaf spring. The main body portion 943 of the input ground plate 94 can be abutted against the surface with a larger pressing force.

Further, in the present embodiment, a surface protrusion group 924 (surface first protrusion 924a and surface second protrusion 924b) protruding laterally is provided on the back surface side of the input ground plate 94 in the sealing portion 92. As a result, the main body portion 943 of the input ground plate 94 can be abutted against the inner peripheral surface of the second accommodating member 56 with a larger pressing force as compared with the case where the surface protrusion group 924 is not provided. ..

Further, in the present embodiment, the back surface projection group 925 (rear surface first projection 925a and back surface second projection 925b) protruding laterally is provided on the back side of the front surface projection group 924 in the sealing portion 92. As a result, the main body portion 943 of the input ground plate 94 can be abutted against the inner peripheral surface of the second accommodating member 56 with a larger pressing force as compared with the case where the back surface protrusion group 925 is not provided. ..

Further, in the present embodiment, a round hole 566 is provided on the side surface of the second accommodating member 56 for accommodating the circuit built-in member 57, and an input ground plate provided on the circuit built-in member 57 is provided at the position where the round hole 566 is formed. The main body part 943 of 94 was arranged. Then, the second accommodating member 56 and the main body portion 943 of the input ground plate 94 are joined by soldering through the round hole 566 provided in the second accommodating member 56. As a result, the joint strength between the second accommodating member 56 and the input grounding plate 94 can be increased as compared with the case where the second accommodating member 56 and the input grounding plate 94 are not soldered. The separation from 94 can be further suppressed.

Further, in the present embodiment, the piezoelectric element 41 and the processing circuit 912 provided on the circuit board 91 are provided inside the first accommodating member 55 connected to the second accommodating member 56 and the second accommodating member 56. It is connected via the conductive member 47. Then, in the pressure detecting device 20, the first accommodating member 55 and the second accommodating member 56 are accommodated inside, and the housing portion 30 electrically insulated from the first accommodating member 55 and the second accommodating member 56 is provided. Provided. As a result, for example, when the pressure detection device 20 is attached to the internal combustion engine 10, various noises that enter the housing portion 30 (housing path) from the internal combustion engine 10 are transferred to the electric path (positive path) of the piezoelectric element 41. And negative routes) can be suppressed.

[others]
In the present embodiment, the second accommodating member 56 and the main body portion 943 provided on the input grounding plate 94 of the circuit built-in member 57 are joined by soldering, but the present invention is not limited to this. For example, a joining method such as laser welding may be used.

Further, in the present embodiment, the negative route and the housing route are separated, but the present invention is not limited to this, and the housing route may be made to function as a negative route. In this case, for example, the diaphragm head 32 and the tip electrode member 42 are brought into direct contact with each other, and the outer peripheral surface of the input grounding plate 94 provided in the circuit built-in member 57 is formed on the inner peripheral surface of the intermediate outer housing 33. You just have to hit it. In this case, for example, the first accommodating member 55 and the second accommodating member 56 become unnecessary.

1 ... Pressure detection system, 10 ... Internal engine, 20 ... Pressure detection device, 30 ... Housing, 31 ... Tip external housing, 32 ... Diaphragm head, 33 ... Intermediate external housing, 34 ... Rear end external housing, 35 ... 1st internal housing, 36 ... 2nd internal housing, 40 ... Detection mechanism, 41 ... Piezoelectric element, 42 ... Tip electrode member, 43 ... Tip insulation member, 44 ... Rear end electrode member, 45 ... Rear end Insulating member, 46 ... 1st coil spring, 47 ... Conducting member, 48 ... Holding member, 49 ... Pressurizing member, 50 ... Insulated pipe, 51 ... First insulating member, 52 ... Second insulating member, 53 ... Support member, 54 ... 2nd coil spring, 55 ... 1st accommodating member, 56 ... 2nd accommodating member, 57 ... circuit built-in member, 58 ... connecting member, 59 ... closing member, 60 ... third insulating member, 70 ... sealing part, 80 ... connection Cable, 91 ... Circuit board, 92 ... Sealing part, 93 ... Input signal plate, 94 ... Input ground plate, 95 ... Power receiving plate, 96 ... Output signal plate, 97 ... Output ground plate, 100 ... Control device

Claims (13)

Piezoelectric elements that output electrical signals according to the pressure received from the outside,
An accommodating member having conductivity and to which one end of the piezoelectric element is connected,
A processing circuit to which the other end of the piezoelectric element is connected and processing the electric signal, a sealing portion having insulation and sealing the processing circuit, and a processing circuit having conductivity and one of which are conductive. The other has a conductive portion exposed to the outside of the side surface of the sealing portion, and the pressure includes a circuit built-in member in which the conductive portion abuts on the accommodating member by being accommodated in the accommodating member. Detection device. The pressure detecting device according to claim 1, wherein the conductive portion in the circuit built-in member is composed of a leaf spring having a restoring force from the side surface of the sealing portion toward the accommodating member. The first or second aspect of the circuit built-in member, wherein the sealing portion is provided behind the conductive portion and has a protrusion protruding from the side surface of the sealing portion toward the accommodating member. Pressure detector. The sealing portion in the circuit built-in member is provided on the back side of the protrusion in the sealing portion, and further has another protrusion protruding from the side surface of the sealing portion toward the accommodating member. 3. The pressure detecting device according to claim 3. The accommodating member is provided with a hole penetrating the inner surface and the outer surface of the accommodating member, and the conductive portion provided in the circuit built-in member is arranged at the hole forming portion, and the hole forming portion is provided. The pressure detecting device according to any one of claims 1 to 4, wherein the accommodating member and the conductive portion are joined to each other. The piezoelectric element is housed inside the housing member and is housed inside the housing member.
Further having a conductive member having conductivity and being accommodated inside the accommodating member and being connected to the piezoelectric element and the processing circuit, further having a conducting member for conducting the electric signal to the processing circuit.
One pole side of the piezoelectric element is connected to the conduction member.
The pressure detecting device according to any one of claims 1 to 5, wherein the other pole side of the piezoelectric element is connected to the accommodating member. The pressure detecting device according to claim 6, wherein the accommodating member is accommodated therein, and a housing portion electrically insulated from the accommodating member is further provided. A processing circuit that is connected to one end of a piezoelectric element that outputs an electrical signal according to the pressure received from the outside and processes the electrical signal.
A sealing portion that has insulating properties and seals the processing circuit,
A circuit-embedded member having conductivity, one connected to the processing circuit and the other having a conductive portion exposed on the side surface of the sealing portion. A processing circuit that processes an electric signal supplied from one pole side of a piezoelectric element, a sealing portion that has insulation and seals the processing circuit, and a processing circuit that has conductivity and one is A step of preparing a circuit-embedded member having a conductive portion connected to and exposed to the outside of the side surface of the sealing portion.
A method for manufacturing a pressure detecting device, comprising a step of accommodating a member having a built-in circuit with respect to an accommodating member having conductivity and connected to the other pole side of the piezoelectric element. The method for manufacturing a pressure detecting device according to claim 9, wherein the conductive portion in the circuit built-in member is composed of a leaf spring having a restoring force from the side surface of the sealing portion toward the accommodating member. .. 9. How to manufacture a pressure detector. The sealing portion in the circuit built-in member is provided on the back side of the protrusion in the sealing portion, and further has another protrusion protruding from the side surface of the sealing portion toward the accommodating member. 11. The method of manufacturing a pressure detecting device according to claim 11. The accommodating member is provided with a hole penetrating the inner surface and the outer surface of the accommodating member, and the conductive portion provided in the circuit built-in member is arranged at a portion where the hole is formed.
One of claims 9 to 12, further comprising a step of joining the accommodating member and the conductive portion at the hole forming portion after accommodating the circuit built-in member in the accommodating member. The method of manufacturing a pressure detector according to the description.

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