Pressure detection device

Abstract

The present invention relates to a pressure detection device. Incomplete combustion products attached to a temperature reduction member can be easily removed even when the sealing performance between the temperature reduction member and the pressure-receiving member is improved. In a pressure detection device (1) having a housing portion that can be mounted on a connecting hole provided in an internal combustion engine, a diaphragm head (32) provided on one end thereof and bearing the pressure of the combustion gas from the internal combustion engine, and a buffer member (80) disposed on the diaphragm head (32) and supplying the combustion gas to the diaphragm head (32) while reducing the temperature of the combustion gas, an internal thread of a first buffer member (81) formed on the buffer member (80) is screwed into an external thread of a second buffer member (82) formed on the buffer member (80).

Description

Technical Field

[0001] The invention relates to a pressure detection device. Background Art

[0002] There is a known device for detecting the pressure of a fluid from an internal combustion engine (for example, Patent Document 1). After such a device has been used for a certain period of time, incomplete combustion products will accumulate on the temperature reduction member that reduces the temperature of the fluid and supplies it to the pressure-receiving member. The accumulation of incomplete combustion products becomes a factor that hinders accurate pressure measurement, and therefore, it is necessary to regularly remove the incomplete combustion products attached to the temperature reduction member.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-056119 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, it is difficult to remove incomplete combustion products from the temperature reducing member in a state where the temperature reducing member and the pressure receiving member are joined by laser welding or the like or are integrally formed so that the temperature reducing member and the pressure receiving member are firmly connected.

[0008] An object of the present invention is to easily remove incomplete combustion products adhering to a temperature lowering member even in a state where the temperature lowering member and the pressure receiving member are firmly connected.

[0009] Means for solving problems

[0010] The pressure detecting device of the present invention for achieving the above-mentioned purpose is characterized in that it comprises: a body capable of being installed in a hole provided in an internal combustion engine, a pressure-receiving member provided at one end side of the body and bearing the pressure of the fluid from the internal combustion engine, and a temperature reducing member arranged on the pressure-receiving member at the front end of the one end side of the body and supplying the fluid to the pressure-receiving member while lowering the temperature of the fluid, the pressure-receiving member comprising a pressure-receiving portion displaced by bearing the pressure, and a pressure-receiving supporting portion joined or integrated with a first member, the first member being joined or integrated with the pressure-receiving member and having an inner circumferential surface, the temperature reducing member comprising the first member and a second member having an outer circumferential surface opposite to the inner circumferential surface, the internal thread formed on the inner circumferential surface of the first member being screwed together (threaded engagement) with the external thread formed on the outer circumferential surface of the second member.

[0011] Here, the first member may be integrally formed with the pressure receiving support portion.

[0012] Furthermore, the second member may be provided with a plurality of communication holes capable of supplying the fluid to the pressure receiving portion.

[0013] Furthermore, the second member screwed to the first member may be arranged at a position not in contact with the pressure receiving member.

[0014] Furthermore, a fixing mechanism for fixing the second member screwed to the first member may be provided.

[0015] Furthermore, the fixing mechanism may be a combination of a threaded hole formed in a threaded portion between the first member and the second member, and a screw threadedly engaged with the threaded hole.

[0016] Furthermore, the threaded hole may be formed in the axial direction of the first member and the second member, and the first member may be provided with a notch portion that fits with a part of the head of the screw screwed into the threaded hole.

[0017] Furthermore, the head of the screw may be cylindrical in shape.

[0018] Furthermore, the threaded hole may be formed in a direction perpendicular to the axial directions of the first member and the second member.

[0019] Furthermore, the head of the screw screwed into the threaded hole may not protrude to the outside from the entrance of the threaded hole.

[0020] Furthermore, one or more linear grooves may be provided on the front end surface of the second member.

[0021] Furthermore, the second member may be divisible into a plurality of members, and the plurality of divided members may be assembled.

[0022] Furthermore, each of the plurality of divided members may be provided with a concave portion and a convex portion that fit together during assembly.

[0023] Effects of the Invention

[0024] According to the present invention, even in a state where the temperature lowering member and the pressure receiving member are firmly connected, the incomplete combustion product adhering to the temperature lowering member can be easily removed. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a side view of the pressure detection device involved in this embodiment.

[0026] Figure 2 This is a schematic configuration diagram showing a state where the pressure detection device is mounted on an internal combustion engine.

[0027] Figure 3 is a cross-sectional view of the pressure detection device ( Figure 1 III-III sectional view).

[0028] Figure 4 It is the front end side of the pressure detection device ( Figure 3 IV region) in an enlarged cross-sectional view.

[0029] Figure 5 (A) is a diagram showing a state where incomplete combustion products are accumulated on the buffer member of the pressure detection device. Figure 5 (B) is a diagram showing a state in which the second buffer member is removed from the pressure detection device.

[0030] Figure 6 This is a perspective view showing an example of the external appearance structure of a buffer member having a screw for fixing a second buffer member screwed into the first buffer member to the first buffer member.

[0031] Figure 7 (A) is to Figure 6 A three-dimensional view of a cross section of a buffer member cut in a radial direction. Figure 7 (B) is to Figure 6 A cross-sectional view of the buffer member cut in the radial direction. Figure 7 (C) to (F) are diagrams showing deformation of the shape of the screw head.

[0032] Figure 8 (A) is a perspective view showing an example of the appearance configuration of a buffer member having a screw for fixing a second buffer member screwed into the first buffer member to the first buffer member. Figure 8 (B) shows Figure 8 (A) is a front view of an example of the appearance structure of the buffer member. Figure 8 (C) is to Figure 8 (A) is a cross-sectional view of the buffer member cut in the radial direction.

[0033] Fig. 9 (A) and (B) are perspective views showing an example of the appearance configuration of the second cushioning member that can be rotated using a jig.

[0034] Fig.10 (A) and (B) are perspective views showing an example of the external appearance structure of a second shock absorbing member which can be divided into a plurality of members and the plurality of divided members can be assembled.

[0035] Description of Reference Numerals

[0036] 1...pressure detection device, 10...internal combustion engine, 32...diaphragm head, 80...buffer member, 81...first buffer member, 82...second buffer member, 82-1 to 82-4...members, 83, 84...screws, 814...inner peripheral surface, 815...notch, 816...threaded hole, 823...outer peripheral surface, 824...through hole, 825...notch, 826...groove, 827...joining surface, 900...tool, 1000...sediment DETAILED DESCRIPTION

[0037] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0038] [Composition of the pressure detection device]

[0039] Figure 1 It is a side view of the pressure detection device 1 according to the present embodiment. Figure 2 1 is a schematic configuration diagram showing a state in which the pressure detection device 1 is mounted on the internal combustion engine 10 . Figure 3 is a cross-sectional view of the pressure detection device 1 ( Figure 1 III-III sectional view). Figure 4 The front end side of the pressure detection device 1 ( Figure 3 IV region) in an enlarged cross-sectional view.

[0040] The pressure detection device 1 according to the present embodiment is a device for detecting the pressure (combustion pressure) in the combustion chamber C of the internal combustion engine 10. After the pressure detection device 1 detects the pressure in the combustion chamber C, a control device (not shown) controls the operation of the internal combustion engine 10 based on the detected pressure. The pressure detection device 1 and the control device are electrically connected via a connection cable 90.

[0041] The pressure detection device 1 comprises: a housing portion 30 which is cylindrical as a whole and is provided in a manner of being exposed to the outside; a detection mechanism portion 40 which includes various mechanisms for detecting pressure and is substantially entirely accommodated in the interior of the housing portion 30 and is provided in a manner of being partially exposed to the outside; a sealing portion 70 which is mounted on the outer peripheral surface of the housing portion 30; and a sealing portion 70 which is mounted on one end side of the housing portion 30 (at the Figure 1 The buffer member 80 is located on the left side of the housing portion 30.

[0042] Here, the structure of the internal combustion engine 10 that is the detection object of the pressure of the pressure detection device 1 is described. The internal combustion engine 10 includes a cylinder block 11 in which a cylinder is formed, a piston 12 that reciprocates in the cylinder, and a cylinder head 13 that is fastened to the cylinder block 11 and forms a combustion chamber C together with the piston 12 and the like. In addition, a connecting hole 13a that connects the combustion chamber C with the outside is provided in the cylinder head 13. The connecting hole 13a includes a step portion 13c located in the middle thereof and a step portion 13b located on the combustion chamber C side relative to the step portion 13c. The connecting hole 13a includes: a small diameter portion located on the combustion chamber C side relative to the step portion 13b and having a smaller inner diameter; a middle diameter portion located on the outer side relative to the step portion 13b and on the combustion chamber C side relative to the step portion 13c and having a larger inner diameter than the small diameter portion; and a large diameter portion located on the outer side relative to the step portion 13c and having a larger inner diameter than the middle diameter portion. Then, the pressure detection device 1 is installed on the internal combustion engine 10 by inserting the front end side of the pressure detection device 1 into the communication hole 13a and fixing the pressure detection device 1 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.

[0043] For the internal combustion engine 10 of such a configuration, the pressure detection device 1 is Figure 1 The left side (the buffer member 80 side) in the combustion chamber C ( Figure 2 The middle is the lower side) and Figure 1 The right side (connection cable 90 side) faces the outside ( Figure 2 In addition, in the following description, Figure 1 In the figure, the left side is referred to as the "front end side" of the pressure detection device 1, and the right side is referred to as the "rear end side" of the pressure detection device 1. In addition, the direction along the axis of the center line is referred to as the "axial direction". In addition, the direction indicating the radius of the pressure detection device 1 is referred to as the "radial direction". In addition, when referring to the radial direction, the direction toward Figure 1 The direction of the center line of the pressure detection device 1 shown by the single-dot chain line is called the "inside", and the direction away from the center line is called the "outside". In addition, in this embodiment, the "front end side" corresponds to the "one end side", and the "rear end side" corresponds to the "other end side".

[0044] (Configuration of the Housing)

[0045] The housing portion 30 as an example of a body includes a front end external housing 31, a diaphragm head 32 mounted on the front end side of the front end external housing 31, an intermediate external housing 33 mounted on the rear end side of the front end external housing 31, and a rear end external housing 34 mounted on the rear end side of the intermediate external housing 33. In addition, the housing portion 30 further includes a first internal housing 35 mounted on the inner side of the front end external housing 31 and on the rear end side of the diaphragm head 32, and a second internal housing 36 mounted on the inner side of the front end external housing 31 and on the rear end side of the first internal housing 35.

[0046] 〔Front end external housing〕

[0047] The front end outer shell 31 is a member having a hollow structure and being cylindrical as a whole. The front end outer shell 31 is made of a metal material such as stainless steel having electrical conductivity and high heat resistance and acid resistance. As such a metal material, SUS630 known as precipitation hardening stainless steel, for example, SUH660 known as austenitic heat-resistant steel (heat-resistant alloy) can be exemplified. However, as long as the required characteristics are met, various metals or various alloys (various stainless steels, various heat-resistant steels or various heat-resistant alloys) can be used.

[0048] The outer diameter of the portion of the front end outer housing 31 inserted into the communication hole 13a of the cylinder head 13 is substantially consistent with the inner diameter of the small diameter portion of the communication hole 13a on the combustion chamber C side, and an extension portion 311 having an outer diameter larger than the inner diameter of the communication hole 13a is provided on the rear end side. After the pressure detection device 1 is mounted on the cylinder head 13, the extension portion 311 of the front end outer housing 31 abuts against the step portion 13c in the communication hole 13a via the first sealing member 71. The surface on the front end side of the extension portion 311 is referred to as a seat surface 312.

[0049] Here, an external thread (not shown) is formed on the outer peripheral surface of the front end outer shell 31. Figure 2 The inner wall of the connecting hole 13a of the cylinder head 13 shown is provided with an internal thread (not shown) that can be screwed with the external thread provided on the front end outer housing 31. In addition, a step portion (not shown) is provided in the connecting hole 13a, which is closer to the front end side than the portion provided with the internal thread, and against which the front end (buffer member 80) of the pressure detection device 1 abuts.

[0050] 〔Diaphragm head〕

[0051] The diaphragm head 32, which is an example of a pressure-bearing member, is a member that is disk-shaped as a whole. The diaphragm head 32 is made of a metal material such as stainless steel that is conductive and has high heat resistance and acid resistance. As such a metal material, there can be exemplified SUS630 known as a precipitation hardening stainless steel, and SUH660 known as an austenitic heat-resistant steel (heat-resistant alloy). However, as long as the required properties can be met, various metals or various alloys (various stainless steels, various heat-resistant steels or various heat-resistant alloys, etc.) other than these can also be used. In addition, in this example, the diaphragm head 32 is made of the same material as the front end external housing 31 (for example, SUS630).

[0052] The diaphragm head 32 has, as an example of a pressure receiving portion, a pressure film 32a that is exposed to the outside (combustion chamber C side) and displaced in accordance with the pressure, and a surface central recess 32b at the center of the front end side. In addition, the diaphragm head 32 has a back annular recess 32c formed by forming a notch in an annular shape on the back side that will become the back (inner) side of the pressure film 32a, and a back central protrusion 32d that protrudes from the center of the pressure film 32a (the portion where the surface central recess 32b is formed) toward the rear end side as a result of the presence of the back annular recess 32c.

[0053] Moreover, the diaphragm head 32 has a back annular convex portion 32e and a surface annular convex portion 32g as an example of a pressure-bearing support portion protruding from the entire circumference of the pressure membrane 32a to the front end side at the rear end side of the peripheral portion of the pressure membrane 32a. The surface annular convex portion 32g is located at a position on the opposite side (front side) of the back annular convex portion 32e. The surface annular convex portion 32g is joined to a part of the first buffer member 81 of the buffer member 80 described later or is formed integrally with the first buffer member 81. In addition, from another point of view, the front end side of the diaphragm head 32 can also be regarded as having a surface annular convex portion 32g formed by forming a notch in a circular shape in its central portion, and a pressure membrane 32a, and a surface central concave portion 32b formed by further forming a notch in the central portion of the pressure membrane 32a.

[0054] The diaphragm head 32 is provided in a manner to block the opening of the front end side in the front end external housing 31. To be more specific, a portion of the front end side of the front end external housing 31 abuts against the back annular convex portion 32e of the diaphragm head 32. In addition, laser welding is performed on the boundary between the diaphragm head 32 and the front end external housing 31 over the entire periphery of the outer surface. The diaphragm head 32 of this embodiment functions as a spring by displacing the periphery of the back annular concave portion 32c, which is the thinnest part, in accordance with the external force. In addition, the diaphragm head 32 vibrates as it receives pressure (external pressure) from the combustion chamber C or the like.

[0055] 〔Intermediate outer shell〕

[0056] The intermediate outer shell 33 is a member having a hollow structure and being cylindrical as a whole. The intermediate outer shell 33 is made of a metal material such as stainless steel having electrical conductivity and high heat resistance and acid resistance. As such a metal material, SUS430LX known as ferritic stainless steel can be exemplified. However, as long as the required properties are met, various metals or various alloys (various stainless steels, various heat-resistant steels or various heat-resistant alloys) can be used in addition to this. In addition, in this example, the intermediate outer shell 33 is made of a material different from that of the front end outer shell 31 (for example, SUS430LX). The front end side of the intermediate outer shell 33 is embedded in the rear end side of the front end outer shell 31. Then, laser welding is performed on the boundary between the intermediate outer shell 33 and the front end outer shell 31 all around the outer circumference.

[0057] 〔Rear end outer shell〕

[0058] The rear end outer shell 34 is a member having a hollow structure and being cylindrical as a whole. The rear end outer shell 34 is made of a metal material such as stainless steel having electrical conductivity and high heat resistance and acid resistance. As such a metal material, SUS430LX known as ferritic stainless steel can be exemplified. However, as long as the required properties are met, various metals or various alloys other than these (various stainless steels, various heat-resistant steels or various heat-resistant alloys, etc.) can be used. In addition, in this example, the rear end outer shell 34 is made of the same material as the middle outer shell 33 (for example, SUS430LX). The front end side of the rear end outer shell 34 is embedded in the rear end side of the middle outer shell 33. In addition, laser welding is performed on the boundary between the rear end outer shell 34 and the middle outer shell 33 all around the outer circumference.

[0059] (Composition of the detection mechanism)

[0060] The detection mechanism 40 includes a conducting member 47, a holding member 48, a second coil spring 54, a first receiving member 55, a second receiving member 56, a circuit built-in member 57, a connecting member 58, a sealing member 59, and a third insulating member 60. In addition, the detection mechanism 40 includes: a piezoelectric element 41 having a piezoelectric body with a piezoelectric effect showing a longitudinal piezoelectric effect; a front electrode member 42, a rear electrode member 44, and a supporting member 53 made of a conductive metal material; and a front insulating member 43, a rear insulating member 45, a first insulating member 51, and a second insulating member 52 made of an insulating ceramic material.

[0061] In addition, the detection mechanism portion 40 includes: a first coil spring 46 that expands and contracts in the axial direction; a pressurizing member 49 that functions as a spring by expanding and contracting the side portion on the front end side, which is the thinnest part, in accordance with the external force; and an insulating tube 50 that has the function of integrating (modularizing) the front end electrode member 42, the piezoelectric element 41, the rear end electrode member 44 and the rear end insulating member 45 with the insulating tube 50 by accommodating them inside the insulating tube 50 and fixing them while making contact with them.

[0062] 〔Conduction components〕

[0063] The conductive member 47 is a member that is rod-shaped as a whole and is arranged inside the front end external housing 31. The conductive member 47 is made of a conductive metal material such as brass, and gold plating is applied to its surface. The conductive member 47 has a front end rod-shaped portion 471 located at the front end side, an intermediate rod-shaped portion 472 located at the rear end side of the front end rod-shaped portion, and a rear end rod-shaped portion 473 located at the rear end side of the intermediate rod-shaped portion. In addition, in the conductive member 47, the outer diameter increases in the order of the front end rod-shaped portion 471, the intermediate rod-shaped portion 472, and the rear end rod-shaped portion 473.

[0064] 〔Retaining member〕

[0065] The retaining member 48 is a member having a hollow structure and being cylindrical as a whole. The retaining member 48 is made of a synthetic resin material such as PPS (Polyphenylenesulfide) or PPT (Polypropylene Terephthalate) having insulating properties. The retaining member 48 has a front end portion located at the front end side, a middle portion located at the rear end side of the front end portion, and a rear end portion located at the rear end side of the middle portion. In the retaining member 48, the outer diameter increases in the order of the front end portion, the middle portion, and the rear end portion. The retaining member 48 is configured to span the inner side of the front end external shell 31 and the inner side of the middle external shell 33. In addition, the above-mentioned conduction member 47 is accommodated and retained inside the retaining member 48.

[0066] [Second coil spring]

[0067] The second coil spring 54 is a member that is spiral-shaped as a whole and expands and contracts in the center line direction. The second coil spring 54 is made of a metal material such as phosphor bronze that has electrical conductivity and high heat resistance, and gold plating is applied to its surface. In addition, in this example, the second coil spring 54 is made of the same material (for example, phosphor bronze) as the first coil spring. The second coil spring 54 is arranged on the inner side of the front end outer housing 31.

[0068] [First storage member]

[0069] The first receiving member 55 is a member having a hollow structure and a cylindrical shape as a whole. The first receiving member 55 is made of a conductive metal material such as brass or stainless steel, and gold-plated on its surface. The first receiving member 55 is arranged inside the front end external housing 31 .

[0070] [Second storage member]

[0071] The second receiving member 56 is a member having a hollow structure and a cylindrical shape as a whole. The second receiving member 56 is made of a conductive metal material such as brass or stainless steel, and gold plating is applied to its surface, similarly to the first receiving member 55. The second receiving member 56 is arranged across the inner side of the front outer housing 31 and the inner side of the middle outer housing 33.

[0072] 〔Circuit built-in components〕

[0073] like Figure 3 As shown in FIG. 1 , the built-in circuit member 57 includes: a circuit substrate 571 for performing various processes using an electronic circuit on an electric signal generated by a weak charge outputted from the piezoelectric element 41; and a sealing portion 572 for sealing the circuit substrate 571 by accommodating the circuit substrate 571 inside. The built-in circuit member 57 is disposed inside the second accommodating member 56 in a substantially entire region except for a portion on the rear end side inside the intermediate outer housing 33. In particular, the entire region of the circuit substrate 571 is disposed inside the second accommodating member 56. In addition, the front end side of the built-in circuit member 57 is embedded in a recess provided on the rear end side of the holding member 48. Furthermore, a metal plate (electrode terminal) provided on the front end side of the built-in circuit member 57 is connected to the rear end side of the conducting member 47. In addition, a metal plate (electrode terminal) provided on the outer peripheral surface of the built-in circuit member 57 is in contact with the inner peripheral surface of the second accommodating member 56.

[0074] 〔Connecting components〕

[0075] The connecting member 58 is a member that is columnar as a whole. The connecting member 58 includes: a base material made of a synthetic resin material such as PPS or PPT having insulation, and wiring and terminals made of a metal material such as copper having conductivity. The connecting member 58 is arranged to span the inner side of the middle outer housing 33 and the inner side of the rear outer housing 34. In addition, the portion (outer peripheral surface) of the connecting member 58 that faces (opposes) the middle outer housing 33 or the rear outer housing 34 is made of a synthetic resin material, and the metal material is not exposed in this portion. The rear end side of the built-in circuit member 57 faces the front end side of the connecting member 58, and the metal plate (electrode terminal) provided on the built-in circuit member 57 is embedded in the terminal provided on the connecting member 58. In addition, on the rear end side of the connecting member 58, the respective conductor portions exposed on the front end side of the power line 91, the signal line 92, and the ground line 93 (the details of which will be described later) constituting the connection cable 90 are inserted. Furthermore, the intermediate outer housing 33 and the connecting member 58 are integrated by press-fitting (interference fitting).

[0076] 〔Closed component〕

[0077] The closing member 59 is a member that is columnar as a whole. However, three through holes are formed in the closing member 59 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 on the inner side of the rear end external shell 34, and the rear end side of the closing member 59 protrudes outward from the rear end of the rear end external shell 34. The front end side of the closing member 59 is opposite to the rear end side of the connecting member 58. In addition, the above-mentioned power line 91, signal line 92 and ground line 93 are inserted into the three through holes provided in the closing member 59. Furthermore, the rear end external shell 34 and the closing member 59 are integrated by press-fitting (interference fit).

[0078] [Third insulating member]

[0079] The third insulating member 60 is a member having a hollow structure and being cylindrical as a whole. However, the third insulating member 60 has a structure in which a cylindrical portion provided at the front end side and a circular annular portion provided at the rear end side are integrated. The third insulating member 60 is made of a synthetic resin material such as PPS having insulating properties. The third insulating member 60 is arranged across the inner side of the front end outer housing 31 and the inner side of the middle outer housing 33.

[0080] (Configuration of the sealing portion)

[0081] like Figure 1 As shown, the sealing portion 70 includes a first sealing member 71 located relatively on the front end side and a second sealing member 72 located relatively on the rear end side.

[0082] [First sealing member]

[0083] The first sealing member 71 is a member that is annular as a whole, and in this example, is composed of a square ring with a quadrilateral cross section. The first sealing member 71 is composed of a copper material that has high heat resistance and acid resistance and is tin-plated on the surface. In addition, the first sealing member 71 is mounted on the outer peripheral surface of the front end external housing 31 that constitutes the housing portion 30. In further detail, the first sealing member 71 is mounted on the outer peripheral surface of the front end external housing 31 in a manner that is in contact with the seat surface 312 of the extension portion 311. Since the seat surface 312 is a surface on the front end side of the extension portion 311, after the pressure detection device 1 is installed on the cylinder head 13 in a state where the first sealing member 71 is installed, the seat surface 312 is opposite to the step portion 13c of the connecting hole 13a across the first sealing member 71.

[0084] [Second sealing member]

[0085] The second sealing member 72 is a member that is annular as a whole, and in this example, is composed of an O-ring with a circular cross-section. The second sealing member 72 is composed of a synthetic rubber material such as fluororubber with high mechanical resilience. In addition, the second sealing member 72 is installed on the outer peripheral surface of the rear end external housing 34 that constitutes the housing portion 30. The second sealing member 72 has the function of a sealing member that prevents water and the like from invading from the outside of the internal combustion engine 10, and also has the function of a vibration-proof member that prevents: the pressure detection device 1 from vibrating and colliding with the inner surface of the connecting hole 13a in the cylinder head 13 due to the vibration of the internal combustion engine 10 and the vibration of the installation environment. Therefore, among materials with high mechanical resilience, fluororubber materials with high resilience and heat resistance and a long life of vibration suppression are suitable for the second sealing member 72.

[0086] (Configuration of Buffer Member)

[0087] The buffer member 80 as an example of a temperature reduction member is a member that is cylindrical as a whole and is arranged at the front end of the pressure detection device 1. The buffer member 80 is a member composed of a first buffer member 81 as an example of a first member and a second buffer member 82 as an example of a second member that is detachably joined to the first member. After the pressure detection device 1 is mounted on the cylinder head 13, the buffer member 80 abuts against the step portion 13b in the communication hole 13a. More specifically, a surface 811 of the first buffer member 81 described later in the buffer member 80 abuts against the step portion 13b in the communication hole 13a.

[0088] [First buffer member]

[0089] The first buffer member 81 is a member composed of a wall that is hollow cylindrical as a whole. The first buffer member 81 has an annular surface 811 on the front end side, and an annular back surface 812 on the rear end side. In addition, the first buffer member 81 has an outer peripheral surface 813 and an inner peripheral surface 814 formed with an internal thread. The inner peripheral surface 814 has a notch 8141 with an inner diameter larger than the inner diameter of the internal thread at one end that is closer to the front end side than the internal thread formed on the inner peripheral surface 814 and connected to the surface 811.

[0090] The first buffer member 81 is made of a metal material (superheat-resistant alloy) having electrical conductivity and higher heat resistance than the diaphragm head 32. As such a metal material, an example can be an iron-based alloy system and a γ' (Gamma prime) precipitation-strengthened superheat-resistant alloy. However, as long as the required properties are met, various superheat-resistant alloys other than this can be used. In addition, as the superheat-resistant alloy that can be used, matrix-strengthened superheat-resistant alloys, carbide precipitation-strengthened superheat-resistant alloys, and γ' precipitation-strengthened superheat-resistant alloys can be cited. In addition, the superheat-resistant alloy that can be used can also be any one of an iron-based alloy system, a nickel-based alloy system, and a cobalt alloy system. In addition, the first buffer member 81 can be made of a copper alloy material with high thermal conductivity such as beryllium copper alloy (JIS C172, hereinafter referred to as BeCu). In addition to BeCu, you can choose admiralty brass (JIS C4430), aluminum brass (JIS C6870), naval brass (JISC4640), etc.

[0091] [Second buffer member]

[0092] The second buffer member 82 is a member that is cylindrical as a whole. The second buffer member 82 has a circular surface 821 on the front end side and a circular back surface 822 on the rear end side. In addition, the second buffer member 82 has an outer peripheral surface 823 formed with an external thread. In addition, the outer peripheral surface 823 of the second buffer member 82 has a boss portion 8231 whose outer shape is larger than the external thread formed on the outer peripheral surface 823. The boss portion 8231 functions as a thread head of the external thread structure provided on the outer peripheral surface 823 described later. The second buffer member 82 has a plurality of cylindrical through holes 824 that pass from the surface 821 that becomes the front end side to the back surface 822 that becomes the rear end side. The through hole 824 is an example of a connecting hole that allows the combustion gas (an example of a fluid) generated in the combustion chamber C to pass through and be supplied to the pressure membrane 32a of the diaphragm head 32.

[0093] The second buffer member 82 is similar to the first buffer member 81, and is composed of a metal material (superheat-resistant alloy) having electrical conductivity and higher heat resistance than the diaphragm head 32. As such a metal material, an example can be given as an iron-based alloy system and a γ' precipitation-strengthened superheat-resistant alloy. However, as long as the required characteristics are met, various superheat-resistant alloys other than this can be used. In addition, as the superheat-resistant alloy that can be used, matrix-strengthened superheat-resistant alloys, carbide precipitation-strengthened superheat-resistant alloys, and γ' precipitation-strengthened superheat-resistant alloys can be cited. In addition, the superheat-resistant alloy that can be used can be any one of an iron-based alloy system, a nickel-based alloy system, and a cobalt alloy system. In addition, the second buffer member 82 can be composed of a copper alloy material having a high thermal conductivity, such as beryllium copper alloy (JISC172, hereinafter referred to as BeCu). Other than BeCu, admiral brass (JIS C4430), aluminum brass (JIS C6870), naval brass (JIS C4640), etc. can be selected. The material constituting the first buffer member 81 and the material constituting the second buffer member 82 may be the same or different.

[0094] [Attachment and removal of the second buffer member]

[0095] As described above, the first buffer member 81 and the second buffer member 82 constituting the buffer member 80 have an internal thread formed on the inner peripheral surface 814 of the first buffer member 81, and an external thread screwed therewith is formed on the outer peripheral surface 823 of the second buffer member 82. This screw mechanism can separate the second buffer member 82 from the first buffer member 81, and can screw the separated second buffer member 82 to the first buffer member 81 again (i.e., attach and detach).

[0096] In the state where the first buffer member 81 and the second buffer member 82 are screwed together, the surface 811 of the first buffer member 81 is located closer to the front end side than the surface 821 of the second buffer member 82, and the central portion formed by the second buffer member 82 on the surface of the buffer member 80 on the front end side is circular and concave, and the peripheral portion formed by the first buffer member 81 is annular and convex throughout the entire circumference. In addition, the central portion formed by the second buffer member 82 on the back side of the buffer member 80 on the rear end side is circular and concave, and the peripheral portion formed by the first buffer member 81 is annular and convex throughout the entire circumference.

[0097] In addition, although not shown in the figure, the central portion formed by the second buffer member 82 in the surface of the front end side of the buffer member 80 obtained by screwing the first buffer member 81 and the second buffer member 82 may be set to a non-concave configuration, that is, a configuration in which the central portion and the peripheral portion of the surface of the front end side of the buffer member 80 are on the same plane, or a configuration in which the central portion is convex and the peripheral portion is concave. Here, whether the central portion formed by the second buffer member 82 in the surface of the front end side of the buffer member 80 obtained by screwing the first buffer member 81 and the second buffer member 82 is set to a concave configuration, set to be on the same plane, or set to a convex configuration is determined by the axial position of the second buffer member 82 screwed to the first buffer member 81. That is, it is determined by the axial position at which the second buffer member 82 screwed into the first buffer member 81 is fixed. The fixing of the second buffer member 82 screwed into the first buffer member 81 will be described later.

[0098] (Relationship between the buffer member and the diaphragm head)

[0099] In this embodiment, the back side 812 of the rear end side of the first buffer member 81 of the buffer member 80 is brought into contact with the surface annular protrusion 32g in the diaphragm head 32, and the boundary portion of the back side 812 and the surface annular protrusion 32g is laser welded all around the outer circumference to integrate them. Therefore, in this example, the diaphragm head 32 and the first buffer member 81 are fixed (welded) in a contacting state. However, the back side 822 of the rear end side of the second buffer member 82 constituting the buffer member 80, and the pressure membrane 32a and the surface central concave portion 32b provided on the front end side of the diaphragm head 32 are confronted with each other across a space.

[0100] In the pressure detection device 1, the back surface 822 of the second buffer member 82 of the buffer member 80 is made to face the pressure membrane 32a and the surface central concave portion 32b of the diaphragm head 32 at a predetermined interval. Therefore, the first buffer member 81 is provided with a notch portion 8141, and the second buffer member 82 is provided with a convex shoulder portion 8231. With such a structure, when the second buffer member 82 is screwed into the first buffer member 81, the convex shoulder portion 8231 abuts against the notch portion 8141, thereby limiting the advancement of the screwing of the second buffer member 82. As a result, the diaphragm head 32 and the second buffer member 82 can be made to face each other at a predetermined interval. As a result, the decline in the function of the diaphragm head 32 caused by the contact between the second buffer member 82 and the diaphragm head 32 can be prevented.

[0101] Furthermore, when the pressure detection device 1 is mounted on the cylinder head 13, the first buffer member 81 contacts the inner wall of the communicating hole 13a. In addition, by screwing the external thread provided on the front end external housing 31 of the pressure detection device 1 into the internal thread of the communicating hole 13a, the side wall of the front end external housing 31 contacts the inner wall of the communicating hole 13a. In addition, even when the central portion formed by the second buffer member 82 in the surface of the front end side of the buffer member 80 obtained by screwing the first buffer member 81 and the second buffer member 82 is configured not to be concave, the side wall of the front end external housing 31 contacts the inner wall of the communicating hole 13a.

[0102] Here, the relationship between the material constituting the buffer member 80 and the material constituting the diaphragm head 32 is described. In the present embodiment, the buffer member 80 and the diaphragm head 32 are both made of alloy materials. However, the buffer member 80 and the diaphragm head 32 are made of different alloy materials. In addition, it is preferable to use an iron-based alloy (steel) for the buffer member 80 and the diaphragm head 32. For the diaphragm head 32, it is preferable to use stainless steel containing 10.5% or more of Cr. On the other hand, for the buffer member 80, it is preferable to use an iron-based alloy (super heat-resistant alloy) that is not stainless steel. In addition, a copper alloy may also be used for the buffer member 80.

[0103] In addition, the alloy material constituting the buffer member 80 preferably has a thermal expansion coefficient close to, and more preferably consistent with, that of the alloy material constituting the diaphragm head 32. In addition, by using a material having a high thermal conductivity such as a copper alloy as the alloy material constituting the buffer member 80, although it is difficult to obtain uniformity in thermal expansion coefficients, on the contrary, it can be expected that a heat absorbing characteristic with a high response to a rapid temperature change of the combustion gas will be exhibited.

[0104] [Connection cable configuration]

[0105] like Figure 1 As shown, the connection cable 90 includes a twisted power line 91, a signal line 92 and a ground line 93, and a sheathing member (not shown) covering the periphery of the power line 91, the signal line 92 and the ground line 93. Here, the power line 91, the signal line 92 and the ground line 93 each have: a conductor portion composed of tinned soft copper strands, and an insulating portion composed of polyethylene (cross-linked polyethylene) or the like whose cross-linking structure is strengthened by electron beams or the like and which covers the periphery of the conductor portion and insulates. In addition, the sheathing member is made of an insulating rubber material or resin material. In addition, in the connection cable 90, a shielding body for shielding the power line 91, the signal line 92 and the ground line 93 may also be provided as needed.

[0106] [Installation steps of pressure detection device to internal combustion engine]

[0107] Here, use Figure 2, the steps for mounting the pressure detection device 1 having the above-mentioned structure on the internal combustion engine 10 are described. First, the pressure detection device 1 is arranged in a communication hole 13a provided in the cylinder head 13 of the internal combustion engine 10 so that its front end side, that is, the buffer member 80 side, faces from the outside of the internal combustion engine 10. Next, the front end side of the pressure detection device 1 is inserted into the inside of the communication hole 13a.

[0108] Next, the pressure detection device 1 is rotated clockwise relative to the axial direction with respect to the cylinder head 13 of the internal combustion engine 10. In addition, this operation is preferably performed using a torque wrench. Accompanying this, the internal thread of the inner peripheral surface of the communication hole 13a provided in the cylinder head 13 is meshed with the external thread provided on the outer peripheral surface of the front end external housing 31 of the pressure detection device 1, and the pressure detection device 1 is screwed into the cylinder head 13. As a result, the buffer member 80 provided on the front end side of the pressure detection device 1 moves toward the combustion chamber C provided in the internal combustion engine 10.

[0109] In addition, as the screwing is performed, the surface 811 of the front end side of the first buffer member 81 provided in the buffer member 80 of the pressure detection device 1 abuts against the step portion 13b in the communication hole 13a of the cylinder head 13 provided in the internal combustion engine 10. In addition, the seat surface 312 of the extension portion 311 provided in the front end external housing 31 of the pressure detection device 1 abuts against the step portion 13c in the communication hole 13a via the first sealing member 71. With this, although the pressure detection device 1 is basically in a state where it is not screwed in further, it is tightened by using a torque wrench, thereby achieving a state where a predetermined axial force (axial force) (tightening and connecting axial force) is applied to the pressure detection device 1 and the cylinder head 13 in the axial direction.

[0110] In the pressure detection device 1 of the present embodiment, the first sealing member 71 is made of a material having greater elasticity than the buffer member 80, and thus deforms when the step portion 13c contacts the pressure detection device 1. Therefore, the position of the pressure detection device 1 relative to the communication hole 13a is determined by the contact between the step portion 13b and the buffer member 80. In addition, in the state where the first buffer member 81 and the second buffer member 82 are screwed together, the buffer member 80 is configured such that the surface 811 of the first buffer member 81 is located at the front end side of the surface 821 of the second buffer member 82. Therefore, the buffer member 80 that contacts the communication hole 13a is only the first buffer member 81. Therefore, the axial force for attaching the pressure detection device 1 to the internal combustion engine 10 is not applied to the second buffer member 82 constituting the buffer member 80. In addition, in the case where the cylinder head 13 is configured without a step, the axial force is applied by the seat surface 312 of the protruding portion 311 and the threaded portion. Through the above, the mounting of the pressure detection device 1 to the internal combustion engine 10, in other words, the fastening and connection of the pressure detection device 1 to the cylinder head 13 is completed.

[0111] [Pressure detection operation by pressure detection device]

[0112] Next, the pressure detection operation performed by the pressure detection device 1 is described. When the internal combustion engine 10 is operating, the pressure (combustion pressure) generated in the combustion chamber C is applied to the pressure film 32a of the diaphragm head 32. Here, in the pressure detection device 1 of the present embodiment, a buffer member 80 is provided on the front end side of the diaphragm head 32, and the combustion gas generated in the combustion chamber C reaches the pressure receiving part (pressure film 32a and surface center concave portion 32b) of the diaphragm head 32 after passing through the through hole 824 of the second buffer member 82 provided in the buffer member 80. In other words, the buffer member 80 receives the combustion gas, and the combustion gas passes through the through hole 824 to reduce the temperature, and the combustion gas with reduced temperature is supplied to the diaphragm head 32.

[0113] Thus, in the diaphragm head 32, the pressure received by the pressure receiving portion is transmitted to the back central convex portion 32d on the back side, and further transmitted from the back central convex portion 32d to the front electrode member 42 via the front insulating member 43. Furthermore, the pressure transmitted to the front electrode member 42 acts on the piezoelectric element 41 sandwiched between the front electrode member 42 and the rear electrode member 44, and an electric charge corresponding to the pressure received is generated in the piezoelectric element 41. The electric charge generated in the piezoelectric element 41 is supplied as a charge signal from the front electrode member 42 or the rear electrode member 44 via the conductive member 47 or the second coil spring 54 and other conductive members to the circuit substrate 571. The charge signal supplied to the circuit substrate 571 is subjected to various processing by a processing circuit (not shown) mounted on the circuit substrate 571 to become an output signal. Furthermore, the output signal output from the circuit substrate 571 is sent to the control device via the wiring and terminals of the connecting member 58 and the connecting cable 90.

[0114] While the combustion gas generated in the combustion chamber C passes through the through hole 824 of the second buffer member 82 provided in the buffer member 80, the buffer member 80 takes away heat, so the temperature of the combustion gas after passing through the buffer member 80 is lower than that of the combustion gas before passing through. Specifically, compared with the case where the buffer member 80 is not provided in the pressure detection device 1, the temperature of the combustion gas reaching the pressure receiving part of the diaphragm head 32 can be reduced by, for example, 100° C. or more.

[0115] [About sediment accumulation]

[0116] Figure 5 (A) is a diagram showing a state where incomplete combustion products (hereinafter referred to as “deposits”) are accumulated on the buffer member 80 of the pressure detection device 1 . Figure 5 (B) is a diagram showing a state in which the second buffer member 82 is removed from the pressure detection device 1 .

[0117] When the pressure detection device 1 is used for a certain period of time, deposits 1000 are deposited on the surface of the buffer member 80 and the pressure receiving portion (pressure film 32a and surface central concave portion 32b) of the diaphragm head 32. In particular, deposits are easily deposited on and around the through hole 824 through which the combustion gas generated in the combustion chamber C passes. If the deposits 1000 are deposited, they will become a factor that hinders the accurate pressure measurement of the pressure detection device 1, and therefore, the operator removes them regularly.

[0118] As described above, the pressure detection device 1 according to the present embodiment can be loaded and unloaded with the second buffer member 82 having the through hole 824 on which the deposit 1000 is easily accumulated. Therefore, the operator periodically removes only the second buffer member 82 from the pressure detection device 1. Specifically, the operator removes the second buffer member 82 screwed to the first buffer member 81 by rotating it in the direction of loosening the screw in the circumferential direction, and washes away the deposit 1000 attached to the second buffer member 82. Then, the operator installs the second buffer member 82 after the deposit is removed to the pressure detection device 1. Specifically, the operator screws the second buffer member 82 by rotating it in the direction of tightening the screw in the circumferential direction by making the external thread of the outer peripheral surface 823 of the second buffer member 82 and the internal thread of the inner peripheral surface 814 of the first buffer member 81 to screw it. Then, the operator installs the pressure detection device 1 to the cylinder head 13 in the above-mentioned manner.

[0119] [Modification 1]

[0120] Depending on how the pressure detection device 1 is used, in the buffer member 80, there is a case where the second buffer member 82 screwed to the first buffer member 81 is accidentally rotated in the circumferential direction of the screw loosening due to some reason. In this case, since the axial position of the second buffer member 82 is offset relative to the first buffer member 81, the second buffer member 82 may fall off from the first buffer member 81. Therefore, a fixing mechanism for fixing the second buffer member 82 screwed to the first buffer member 81 may be provided in the buffer member 80.

[0121] Figure 6 This is a perspective view showing an example of the external appearance configuration of the buffer member 80 including screws 83 for fixing the second buffer member 82 screwed into the first buffer member 81 to the first buffer member 81 . Figure 7 (A) is to Figure 6 The buffer member 80 is a three-dimensional view of a cross section obtained by cutting in the radial direction. Figure 6 In the example with two screws 83, Figure 7 In (A), one of the two screws 83 is not shown in the figure for easy understanding of the description. Figure 7(B) is to Figure 6 80 is a cross-sectional view obtained by cutting the buffer member 80 in the radial direction.

[0122] exist Figure 6 as well as Figure 7 The buffer member 80 shown in (A) and (B) is an example of a fixing mechanism for fixing the second buffer member 82 screwed to the first buffer member 81, and is provided with: a combination of a threaded hole formed in the screwing portion of the first buffer member 81 and the second buffer member 82, and a screw 83 screwed into the threaded hole.

[0123] The threaded hole for screwing the screw 83 is formed in the axial direction of the first buffer member 81 and the second buffer member 82. Specifically, the threaded hole extending in the axial direction is formed in the portion including the surface 811 and the inner peripheral surface 814 of the front end side of the first buffer member 81 and the portion of the second buffer member 82. Among them, the portion of the threaded hole formed on the first buffer member 81 side is formed with a notch portion 815 that fits with a portion of the head 831 of the screw 83 screwed into the threaded hole.

[0124] When the screw 83 for fixing the second buffer member 82 is screwed into the portion where the first buffer member 81 and the second buffer member 82 are threaded together, a portion of the head 831 of the screw 83 is engaged with the notch 815, and the threaded portion 832 of the screw 83 is arranged across the first buffer member 81 and the second buffer member 82. Thus, the head 831 of the screw 83 engaged with the notch 815 and the threaded portion 832 arranged across the first buffer member 81 and the second buffer member 82 act as a wedge to suppress accidental circumferential rotation of the second buffer member 82. As a result, it is possible to suppress the axial position change of the second buffer member 82 and suppress the second buffer member 82 from falling off. In addition, in Figure 6 In the example shown, two fixing mechanisms consisting of a screw 83 and a threaded hole for screwing the screw 83 are arranged at positions opposite to each other across the center line. The fixing mechanism is not limited to two as in this example, and one or more than two fixing mechanisms may be provided. In the case of providing a plurality of fixing mechanisms, it is preferred that they are arranged symmetrically with respect to the central axis of the second buffer member 82. For example, in the case of providing three fixing mechanisms, each fixing mechanism is arranged at intervals of 120 degrees in the circumferential direction of the buffer member 80 with the central axis as the center. In addition, in the case of providing four fixing mechanisms, each fixing mechanism is arranged at intervals of 90 degrees in the circumferential direction of the buffer member 80 with the central axis as the center.

[0125] Figure 7 (C) to (F) are diagrams showing deformation of the shape of the head 831 of the screw 83 .

[0126] The above Figure 7 The screw 83 shown in (A) and (B) is a screw that is cylindrical as a whole and has a disc-shaped head 831. However, as long as the characteristics required as a fixing mechanism for fixing the second buffer member 82 screwed to the first buffer member 81 are satisfied, screws of other shapes may also be used.

[0127] For example, in Figure 7 In (C) and (D), a top view and a front view are respectively shown showing an example of the appearance structure of a screw 83 having a cylindrical head 831. Figure 7 (E) and (F) of FIG. 8 show a top view and a front view, respectively, of an example of the appearance of a screw 83 in which the shape of the head 831 has an edge inclined relative to the length direction of the screw 83. When the screw 83 in which the head 831 is cylindrical is used as the fixing mechanism, the shape of the head 831 is cylindrical, and therefore, compared with the case in which the shape of the head 831 of the screw 83 has an edge inclined relative to the length direction of the screw 83, it is possible to suppress the intrusion of combustion gas into the threaded hole and prevent the screw 83 from being attached and fixed.

[0128] [Modification 2]

[0129] Figure 8 (A) is a perspective view showing an example of the external appearance configuration of the buffer member 80 including a screw 84 for fixing the second buffer member 82 screwed into the first buffer member 81 to the first buffer member 81 . Figure 8 (B) shows Figure 8 (A) is a front view of an example of the appearance structure of the buffer member 80. Figure 8 (C) is to Figure 8 (A) is a cross-sectional view of the buffer member 80 cut in the radial direction.

[0130] exist Figure 8 The buffer member 80 shown in (A) to (C) is an example of a fixing mechanism for fixing the second buffer member 82 screwed to the first buffer member 81, and is provided with a combination of a threaded hole formed in the screwing portion of the first buffer member 81 and the second buffer member 82, and a screw 84 screwed into the threaded hole.

[0131] The threaded hole for screwing the screw 84 is formed in a direction perpendicular to the axial direction of the first buffer member 81 and the second buffer member 82. Specifically, a threaded hole 816 extending in the radial direction of the axial direction is formed in a portion including a portion of each of the outer circumferential surface 813 and the inner circumferential surface 814 of the first buffer member 81 and a portion of the outer circumferential surface 823 of the second buffer member 82. Among them, a portion of the threaded hole 816 formed on the inner circumferential surface 814 of the first buffer member 81 is formed with a notch portion 817 that fits with a portion of the screw 84 screwed into the threaded hole 816. In addition, a portion of the threaded hole 816 formed on the second buffer member 82 side is formed with a notch portion 825 that fits with a portion of the screw 84 screwed into the threaded hole 816.

[0132] In addition, Figure 8 In the example shown, two fixing mechanisms consisting of a screw 84 and a threaded hole 816 for screwing the screw 84 are arranged at positions facing each other across a predetermined surface that is parallel to and includes the center line, but the fixing mechanism is not limited to two as in this example, and one or more than two fixing mechanisms may be provided. For example, in the case of providing three fixing mechanisms, the threaded holes 816 are provided at positions where the outer peripheral surface 813 of the first buffer member 81 is divided into three parts in the circumferential direction. In addition, it is preferred that in the case of providing four fixing mechanisms, the threaded holes 816 are provided at positions where the outer peripheral surface 813 of the first buffer member 81 is divided into four parts in the circumferential direction to arrange the fixing mechanisms.

[0133] When the screw 84 for fixing the second buffer member 82 is screwed into the portion where the first buffer member 81 and the second buffer member 82 are threaded together, a portion of the screw 84 engages with the notch 817 on the first buffer member 81 side and the notch 825 on the second buffer member 82 side. Thus, the portion of the screw 84 that engages with the notch 817 on the first buffer member 81 side and the notch 825 on the second buffer member 82 side acts as a wedge to suppress the accidental circumferential rotation of the second buffer member 82. As a result, it is possible to suppress the accidental circumferential rotation of the second buffer member 82 and the fall-off. In addition, in the case where the threaded hole 816 is provided in a direction orthogonal to the axial direction, as described above, Figure 6 Compared to the case where a threaded hole is provided in the axial direction as in the example, since the threaded hole 816 is provided at a position away from the combustion chamber C of the internal combustion engine 10, the threaded hole is not directly exposed to the combustion gas from the combustion chamber C, and the risk of deformation and / or breakage caused by repeated thermal expansion and thermal contraction of the screw 84 and / or the accumulation of deposits in the threaded hole 816 can be suppressed.

[0134] in addition, Figure 8The screw 84 shown in (A) to (C) is a so-called headless set screw that is cylindrical in shape and whose head and body are not clearly distinguished. The screw 84 has a surface 841 on one end side in the longitudinal direction for engaging a tool such as a hexagonal wrench, and a surface 842 on the other end side in the longitudinal direction. In addition, the screw 84 has an outer peripheral surface 843. In addition, an external thread (not shown) is formed on the outer peripheral surface 843. In addition, an internal thread (not shown) that can be screwed with the above-mentioned external thread provided on the outer peripheral surface 843 is formed on the inner wall of the threaded hole 816.

[0135] In addition, the screw 84 is screwed into the threaded hole 816 as a whole, and there is no portion protruding from the entrance of the threaded hole 816 to the outside. Therefore, when the pressure detection device 1 is installed on the internal combustion engine 10, it is possible to prevent the head of the screw protruding from the outer peripheral surface 813 of the first buffer member 81 from damaging the inner wall of the connecting hole 13a of the internal combustion engine 10. Figure 8 Since the threaded hole 816 is provided on the outer peripheral surface 813 of the first buffer member 81, the Figure 6-7 Compared with the example of the screw with a head as in the modified example 1 shown, there is a risk of disadvantage in the sealing between the screw 84 and the threaded hole 816, but the risk of sealing can be reduced by adopting a headless set screw with a small diameter as the screw 84.

[0136] [Variation 3]

[0137] As described above, according to the present embodiment, since the second buffer member 82 can be attached and detached, it is possible to efficiently remove the deposits attached to the second buffer member 82. However, depending on the situation, there is a case where the deposits attached to the second buffer member 82 are accumulated and fixed, and the second buffer member 82 cannot be smoothly rotated in the direction of loosening the screw in the circumferential direction.

[0138] Fig. 9 (A) and (B) are perspective views showing an example of the external appearance configuration of the buffer member 80 in which the second buffer member 82 can be rotated using a tool.

[0139] exist Fig. 9 The surface 821 of the front end side of the second buffer member 82 of the buffer member 80 shown in (A) and (B) has two straight grooves 826 extending in the radial direction arranged orthogonally. The groove 826 can be engaged with a tool 900 such as a flat-blade screwdriver. The operator uses the tool 900 to dig out the sediment until the groove 826 is exposed, and the tool 900 is engaged with the exposed groove 826. Thus, the second buffer member 82 can be easily rotated in the circumferential direction.

[0140] [Variation 4]

[0141] As described above, according to the present embodiment, since the second buffer member 82 can be attached and detached, it is possible to efficiently remove the deposits attached to the second buffer member 82. However, even when the second buffer member 82 is removed from the first buffer member 81, there is a case where the deposits clog the through hole 824 and cannot be removed smoothly even by cleaning, depending on the situation.

[0142] Fig.10 (A) and (B) are perspective views showing an example of the external appearance structure of the second buffer member 82 which can be divided into a plurality of components and the divided plurality of components can be assembled.

[0143] exist Fig.10 (A) shows a second buffer member 82 formed by combining a plurality of members. Fig.10 (B) shows the second buffer member 82 in a state of being divided into a plurality of members.

[0144] Fig.10 The second buffer member 82 shown in (A) is formed by members 82-1 to 82-4 that can be combined. Specifically, member 82-1 is combined with members 82-2 and 82-4 via a joint surface 827, and member 82-2 is combined with members 82-1 and 82-3 via a joint surface 827. In addition, member 82-3 is combined with members 82-2 and 82-4 via a joint surface 827, and member 82-4 is combined with members 82-1 and 82-3 via a joint surface 827. As a result of these combinations, the second buffer member 82 is formed.

[0145] The joint surface 827 is a surface formed by the components 82-1 to 82-4, and is provided with a concave portion 827a and a convex portion 827b that fit together during assembly. When assembling the divided multiple components, the concave portion 827a and the convex portion 827b fit together, so that the assembly can be performed without causing deviation. In addition, the assembly can be performed regardless of the arrangement of the multiple components.

[0146] so, Fig.10 The second buffer member 82 shown in (A) can be divided into members 82-1 to 82-4, so that the deposits attached to the second buffer member 82 can be easily removed. In addition, since the divided members 82-1 to 82-4 can be assembled via the joint surface 827, after being divided into members 82-1 to 82-4 and removing the deposits, the members 82-1 to 82-4 can be assembled and used again as the second buffer member 82. In addition, the members 82-1 to 82-4 can each be set to the same shape. In this case, it is not necessary to consider the object of assembly during assembly. In addition, replacement due to damage or the like also becomes easy.

[0147] As described above, the pressure detection device 1 to which the present invention is applied only needs to have the following configuration, and various embodiments can be adopted.

[0148] That is, the pressure detection device 1 to which the present invention is applied is the following pressure detection device, characterized in that it comprises: a body (housing portion 30) that can be mounted on the connecting hole 13a provided in the internal combustion engine 10; a pressure-receiving member (diaphragm head 32) provided on one end side of the body and receiving the pressure of the fluid (combustion gas) from the internal combustion engine 10; and a temperature-reducing member (buffer member 80) arranged on the pressure-receiving member at the front end of one end side of the body and supplying the fluid to the pressure-receiving member while reducing the temperature of the fluid, the pressure-receiving member comprising: The temperature reducing member comprises a pressure-bearing portion (pressure membrane (surface) 32a and a central recess 32b on the surface), and a pressure-bearing supporting portion (surface annular protrusion 32g) screwed together or integrally formed with the first member (first buffer member 81), the first member being joined to or integrated with the pressure-bearing member and having an inner circumferential surface 814, the temperature reducing member comprising the first member and a second member (second buffer member 82) having an outer circumferential surface 823 opposite to the inner circumferential surface 814, the internal thread formed on the inner circumferential surface 814 of the first member being screwed together with the external thread formed on the outer circumferential surface 823 of the second member.

[0149] The temperature reduction member for supplying the fluid from the internal combustion engine 10 to the pressure-receiving member is composed of a first member joined to or integrally formed with the pressure-receiving member and a second member screwed to the first member, so that the second member can be attached and detached. Thus, it is possible to facilitate the removal of the deposit 1000 attached to the temperature reduction member. In addition, in the configuration in which no axial force is applied to the second member when the second member is screwed to the first member, the influence of the attachment and detachment of the second member on the sealing performance of the pressure detection device and the internal combustion engine can be reduced.

[0150] Here, the first member and the pressure-receiving support portion may be integrally formed.

[0151] Since the first member and the pressure-receiving member are integrally formed, the sealing performance between the first member and the pressure-receiving member is improved.

[0152] In addition, a plurality of communication holes (through holes 824 ) that can supply the fluid to the pressure receiving portion may be provided in the second member.

[0153] Since the deposits 1000 are easily accumulated in the communicating holes of the second member that can be attached and detached by the screw mechanism, the deposits can be efficiently removed by removing the second member and washing it.

[0154] In addition, the second member screwed to the first member may be arranged at a position not in contact with the pressure-receiving member.

[0155] Since the second member screwed to the first member is fixed at a position not in contact with the pressure-receiving member, it is possible to prevent the function of the pressure-receiving member from being deteriorated due to the contact between the second member and the pressure-receiving member.

[0156] In addition, a fixing mechanism for fixing the second member screwed to the first member may be provided.

[0157] Since the second member screwed to the first member is fixed, it is possible to prevent the second member from accidentally falling off.

[0158] In addition, the fixing mechanism may be a combination of a threaded hole formed in the threaded engagement portion between the first member and the second member, and a screw (for example, screws 83 and 84 ) threadedly engaged with the threaded hole.

[0159] Since the screw for fixing the second member is screwed into the threaded portion between the first member and the second member, it is possible to suppress the second member from coming off due to unintentional rotation of the second member.

[0160] Alternatively, the threaded holes may be formed in the axial direction of the first member and the second member, and the first member may be provided with a notch that fits with a portion of the head 831 of a screw (eg, screw 83) screwed into the threaded hole.

[0161] Since the first member is provided with the notch portion into which a part of the head portion 831 of the screw of the fixing mechanism fits, it is possible to suppress the second member from falling off due to unintended rotation of the second member.

[0162] In addition, the shape of the screw head 831 can be cylindrical (for example, Figure 7 (C) and (D) screws 83).

[0163] Since the head 831 of the screw as the fixing mechanism is cylindrical in shape, the head 831 of the screw has a side inclined with respect to the length direction of the screw (for example, Figure 7 Compared with the screws 83 of (E) and (F), the supplied fluid can be prevented from intruding into the threaded hole.

[0164] In addition, the threaded hole may be formed in a direction perpendicular to the axial direction of the first member and the second member (for example, Figure 8 (A) threaded hole 816).

[0165] Since the threaded holes of the fixing mechanism are provided in a direction perpendicular to the axial direction of the first member and the second member, the fixing mechanism can be provided with a plurality of threaded holes in the axial direction of the first member and the second member. Figure 6Compared with the threaded hole into which the screw 83 is screwed, the threaded hole is provided at a position away from the combustion chamber of the internal combustion engine. Therefore, the risk of deformation and / or breakage caused by repeated thermal expansion and thermal contraction of the screw and / or the accumulation of deposits in the threaded hole can be suppressed.

[0166] In addition, the head of the screw screwed into the threaded hole (e.g. Figure 8 The screw 84 of (A) may not be threaded from the threaded hole (for example, Figure 8 The entrance of the threaded hole (A) 816) protrudes to the outside.

[0167] Since the head of the screw screwed into the threaded hole of the fixing mechanism does not protrude from the entrance of the threaded hole, it is possible to prevent the head of the screw from damaging the inner wall of the hole of the internal combustion engine when the pressure detection device is mounted on the internal combustion engine.

[0168] In addition, one or more linear grooves 826 may be provided on the front end surface of the second member.

[0169] Since the linear groove 826 is provided on the front end surface of the second member to which the deposit 1000 is likely to adhere, the deposit 1000 can be easily removed by inserting the tool 900 into the groove 826 .

[0170] Alternatively, the second member may be divisible into a plurality of members (eg, members 82 - 1 to 82 - 4 ), and the plurality of divided members may be assembled.

[0171] Since the second member can be divided into a plurality of members, it is possible to facilitate the removal of the deposit 1000 attached to the second member. In addition, since the divided plurality of members can be assembled, the divided plurality of members can be reassembled after the deposit 1000 is removed and used again as the second member.

[0172] In addition, each of the plurality of divided components may be provided with a concave portion and a convex portion (for example, Fig.10 (A) bonding surface 827).

[0173] When assembling the divided multiple components, the concave portion and the convex portion are fitted together, so that the components can be assembled without causing any deviation. In addition, the components can be assembled without considering the arrangement of the multiple components.

[0174] [other]

[0175] In the above-mentioned embodiment, the second buffer member 82 of the buffer member 80 is provided with 19 cylindrical through holes 824, but the present invention is not limited thereto. That is, as long as the temperature of the combustion gas can be lowered by passing the combustion gas through the buffer member 80, the shape, number, size, and arrangement of the through holes 824 may be appropriately changed.

[0176] In addition, Figure 6 In the embodiment, the cross screws as the screws 83 are arranged at two positions opposite to each other across the center line, but the present invention is not limited to this. That is, as long as the screws 83 function as a fixing mechanism, the shape, size, arrangement, etc. may be appropriately changed. For example, instead of a cross screw, a headless set screw with a hexagonal hole may be used. In the case of a headless set screw with a hexagonal hole, the head diameter of the screw can be reduced.

[0177] In addition, Fig.10 , the second buffer member 82 is divided into four parts, but the present invention is not limited thereto. That is, any second buffer member 82 can be divided into n parts (n is an integer greater than 2) and assembled.

[0178] In addition, in the above-mentioned embodiment, the central portion formed by the second buffer member 82 on the back surface of the rear end side of the buffer member 80 obtained by screwing the first buffer member 81 and the second buffer member 82 is set to be a concave configuration, but the present invention is not limited thereto. That is, it is also possible to set the central portion formed by the second buffer member 82 on the back surface of the rear end side of the buffer member 80 obtained by screwing the first buffer member 81 and the second buffer member 82 to be a non-concave configuration, that is, the central portion and the peripheral portion of the surface of the rear end side of the buffer member 80 are on the same plane.

[0179] The present embodiment has been described above, but the technical scope of the present invention is not limited to the above-mentioned embodiment. Various changes and substitutions of the configuration that do not deviate from the scope of the technical idea of ​​the present invention are included in the present invention. In the above-mentioned embodiment, the case where the piezoelectric element 41 is adopted for the detection mechanism part 40 of the pressure detection device 1 is described, but the configuration of the detection mechanism part 40 can be replaced with various forms of detection mechanisms known in the past. For example, a strain gauge or the like can be used instead of the piezoelectric element 41. When a strain gauge is used, in addition to the above-mentioned embodiment, it is necessary to set a power supply path for the power supply to the strain gauge in the pressure detection device.

Claims

1. A pressure detection device, characterized in that: The invention comprises: a body that can be mounted on a hole provided in an internal combustion engine; a pressure-receiving member provided on one end side of the body and receiving the pressure of a fluid from the internal combustion engine; and a temperature-reducing member disposed on the pressure-receiving member at the front end of the one end side of the body and supplying the fluid to the pressure-receiving member while reducing the temperature of the fluid. The pressure-receiving member includes a pressure-receiving portion that is displaced by receiving pressure and a pressure-receiving support portion that is joined or integrated with a first member, wherein the first member is joined or integrated with the pressure-receiving member and has an inner peripheral surface. The temperature lowering member includes the first member and a second member having an outer peripheral surface facing the inner peripheral surface. The internal thread formed on the inner peripheral surface of the first member is threadedly engaged with the external thread formed on the outer peripheral surface of the second member. The pressure detection device is provided with a fixing mechanism for fixing the second member screwed to the first member. The fixing mechanism is a combination of a threaded hole formed in a threaded engagement portion between the first member and the second member and a screw threadedly engaged with the threaded hole.

2. The pressure detection device according to claim 1, characterized in that: The first member is formed integrally with the pressure receiving support portion.

3. The pressure detection device according to claim 1, characterized in that: The second member is provided with a plurality of communication holes capable of supplying the fluid to the pressure receiving portion.

4. The pressure detection device according to claim 1, characterized in that: The second member screwed to the first member is arranged at a position not in contact with the pressure receiving member.

5. The pressure detection device according to claim 1, characterized in that: The threaded hole is formed in the axial direction of the first member and the second member. The first member is provided with a notch portion into which a part of the head of the screw screwed into the threaded hole is fitted.

6. The pressure detection device according to claim 5, characterized in that: The head of the screw is cylindrical in shape.

7. The pressure detection device according to claim 1, characterized in that: The threaded hole is formed in a direction perpendicular to the axial directions of the first member and the second member.

8. The pressure detection device according to claim 7, characterized in that: The head of the screw screwed into the threaded hole does not protrude to the outside from the entrance of the threaded hole.

9. The pressure detection device according to claim 1, characterized in that: One or more linear grooves are provided on the front end surface of the second member.

10. A pressure detection device, characterized in that: The invention comprises: a body that can be mounted on a hole provided in an internal combustion engine; a pressure-receiving member provided on one end side of the body and receiving the pressure of a fluid from the internal combustion engine; and a temperature-reducing member disposed on the pressure-receiving member at the front end of the one end side of the body and supplying the fluid to the pressure-receiving member while reducing the temperature of the fluid. The pressure-receiving member includes a pressure-receiving portion that is displaced by receiving pressure and a pressure-receiving support portion that is joined or integrated with a first member, wherein the first member is joined or integrated with the pressure-receiving member and has an inner peripheral surface. The temperature lowering member includes the first member and a second member having an outer peripheral surface facing the inner peripheral surface. The internal thread formed on the inner peripheral surface of the first member is threadedly engaged with the external thread formed on the outer peripheral surface of the second member. The second member can be divided into a plurality of members, and the plurality of divided members can be assembled. Each of the plurality of divided members is provided with a concave portion and a convex portion that fit together during assembly.

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