WO2020039740A1 - Pressure sensor - Google Patents

Abstract

[Problem] To enhance detection precision even when a pressure wave including transverse wave oscillation is received. [Solution] A pressure sensor 1 is provided with a diaphragm 2, a pressure transmission rod 3 having an element installation part 3b and a pressure transmission part 3a, and a pressure sensing part 5 provided in an installation position of the element installation part 3b. In a position in the axial direction of the pressure transmission rod 3 that differs from the installation position at which the pressure sensing part 5 is installed, the axial direction being the center axis O in the pressure transmission direction, the pressure transmission rod 3 has an asymmetrical rigid part 3d for increasing the resonance frequency of oscillation caused in the pressure transmission rod 3 by a pressure wave transmitted via the diaphragm 2.

Description

Pressure sensor

The present invention relates to a pressure sensor.

As a pressure sensor used for detecting the combustion pressure of an internal combustion engine for a vehicle, the pressure applied to the diaphragm is transmitted to a sensor plate having a sensor unit, and a sensor signal corresponding to the pressure of the measurement medium is output from the sensor unit. What is known is. In this pressure sensor, the sensor plate is slightly bent in a bow shape in advance, and further bent according to the pressure to apply a strain to the sensor unit (for example, see Patent Document 1).

Japanese Patent Application Laid-Open No. 2009-128036

た め In Patent Document 1, since the detection is performed by bending the sensor plate, a transverse wave vibration is generated when a pulse-like pressure wave is received. Generally, the vibration of the shear wave has a low natural frequency, and when a pressure wave including a high frequency component such as knocking is received, the vibration is induced and the detection accuracy is reduced.

A pressure sensor according to one aspect of the present invention includes a pressure-receiving diaphragm, an element installation section, and a pressure transmission rod having a pressure transmission section provided between the diaphragm and the element installation section. A pressure detection unit provided at the installation position of the element installation unit, and detects and outputs distortion generated within a range including the installation position of the pressure detection unit according to a compressive force received from the diaphragm. A sensor, wherein the pressure transmission rod is transmitted via the diaphragm to a position different from the installation position where the pressure detection unit is installed in an axial direction of the pressure transmission rod, which is a central axis in a pressure transmission direction. An asymmetric rigid portion for increasing the resonance frequency of vibration generated in the pressure transmission rod due to the pressure wave.

According to the present invention, it is possible to provide a pressure sensor having improved detection accuracy.

FIG. 1 is an external perspective view of a first embodiment of the pressure sensor of the present invention. FIG. 2 is an exploded perspective view of the pressure sensor shown in FIG. FIG. 3 is a longitudinal sectional view of the pressure sensor shown in FIG. FIG. 4 is a sectional view of an essential part of the pressure sensor shown in FIG. FIG. 5A is a diagram illustrating one region of each of the element installation portion and the asymmetric rigid portion in FIG. 4, and FIG. 5B is a diagram with respect to the central axis of the pressure transmission rod in a region IIb of FIG. FIG. 5C is a schematic diagram illustrating a high rigidity side and a low rigidity side, and FIG. 5C is a schematic diagram illustrating a high rigidity side and a low rigidity side with respect to a center axis of the pressure transmission rod in a region IIc of FIG. FIG. 6A is a diagram illustrating a deformed state of the pressure transmitting rod in the pressure receiving state of the comparative product having no asymmetric rigid portion, and FIG. 6B is a diagram illustrating the deformation of the pressure transmitting rod in the pressure receiving state of the present embodiment. The figure which shows a state. 7A and 7B show the amount of strain detected when a pressure wave (20 kHz) is applied. FIG. 7A is a response characteristic diagram of a comparative product, and FIG. 7B is a response characteristic of the present embodiment. FIG. 8A and 8B show a pressure sensor according to a second embodiment of the present invention. FIG. 8A is a sectional view of a main part including an element installation part and an asymmetric rigid part, and FIG. 8C is a schematic diagram showing the high rigidity side and the low rigidity side of the region VIIIb, and FIG. 8C is a schematic diagram showing the high rigidity side and the low rigidity side of the region VIIIc in FIG. 9A and 9B show a third embodiment of the pressure sensor of the present invention. FIG. 9A is a cross-sectional view of a main part including an element installation part and an asymmetric rigid part, and FIG. 9B is FIG. FIG. 9C is a schematic diagram showing the high rigidity side and the low rigidity side of the region IXb in FIG. 9A. FIG. 9C is a schematic diagram showing the high rigidity side and the low rigidity side of the region IXc in FIG. FIG. 10 shows a fourth embodiment of the pressure sensor of the present invention. FIG. 10 (a) is a sectional view of a main part including an element installation portion and an asymmetric rigid portion, and FIG. 10 (b) is FIG. 10 (a). 10C is a schematic diagram showing the high rigidity side and the low rigidity side of the region Xb, and FIG. 10C is a schematic diagram showing the high rigidity side and the low rigidity side of the region Xc in FIG. 11A and 11B show a fifth embodiment of the pressure sensor of the present invention. FIG. 11A is a sectional view of a main part including an element installation part and an asymmetric rigid part, and FIG. 11B is FIG. 11C is a schematic diagram showing the high rigidity side and the low rigidity side of the region XIb, and FIG. 11C is a schematic diagram showing the high rigidity side and the low rigidity side of the region XIc in FIG. FIG. 12 shows a sixth embodiment of the pressure sensor of the present invention. FIG. 12 (a) is a sectional view of a main part including an element installation part and an asymmetric rigid part, and FIG. 12 (b) is FIG. 12C is a schematic diagram showing a high rigidity side and a low rigidity side of a region XIIb, and FIG. 12C is a schematic diagram showing a high rigidity side and a low rigidity side of a region XIIc in FIG. FIG. 13 shows a seventh embodiment of the pressure sensor of the present invention. FIG. 13 (a) is a sectional view of a main part including an element installation part and an asymmetric rigid part, and FIG. 13 (b) is FIG. 13 (a). 13C is a schematic diagram showing a high rigidity side and a low rigidity side of a region XIIIb, and FIG. 13C is a schematic diagram showing a high rigidity side and a low rigidity side of a region XIIIc in FIG. FIG. 14 shows an eighth embodiment of the pressure sensor of the present invention. FIG. 14 (a) is a sectional view of a main part including an element installation part and an asymmetric rigid part, and FIG. 14 (b) is FIG. 14 (a). 14C is a schematic diagram showing the high rigidity side and the low rigidity side of the region XIVb, and FIG. 14C is a schematic diagram showing the high rigidity side and the low rigidity side of the region XIVc in FIG. FIG. 15 shows a ninth embodiment of the pressure sensor of the present invention. FIG. 15 (a) is a sectional view of a main part including an element installation part and an asymmetric rigid part, and FIG. 15 (b) is FIG. 15C is a schematic diagram showing the high rigidity side and the low rigidity side of the region XVb, FIG. 15C is a schematic diagram showing the high rigidity side and the low rigidity side of the region XVc in FIG. 15A, and FIG. FIG. 16 is a schematic diagram showing a high rigidity side and a low rigidity side of a region XVd in FIG. 16A and 16B show a pressure sensor according to a tenth embodiment of the present invention. FIG. 16A is a sectional view of a main part including an element installation part and an asymmetric rigid part, and FIG. 16B is FIG. 16C is a schematic diagram showing a high rigidity side and a low rigidity side of a region XVIb, and FIG. 16C is a schematic diagram showing a high rigidity side and a low rigidity side of a region XVIc in FIG. FIG. 17 is a diagram showing a deformed state of the pressure transmission rod in the pressure receiving state shown in FIG. 16.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description and drawings are exemplifications for describing the present invention, and are omitted and simplified as appropriate for clarification of the description. The present invention can be implemented in other various forms. Unless otherwise specified, each component may be singular or plural.
The position, size, shape, range, and the like of each component illustrated in the drawings may not necessarily represent the actual position, size, shape, range, or the like, in order to facilitate understanding of the present invention. Therefore, the present invention is not necessarily limited to the position, size, shape, range, and the like disclosed in the drawings.
When there are a plurality of components having the same or similar functions, the same reference numerals may be given different subscripts for explanation. However, when it is not necessary to distinguish between these components, the description may be omitted with suffixes omitted.

-First embodiment-
FIG. 1 is an external perspective view of a first embodiment of the pressure sensor of the present invention, FIG. 2 is an exploded perspective view of the pressure sensor shown in FIG. 1, and FIG. 3 is a perspective view of the pressure sensor shown in FIG. It is a longitudinal cross-sectional view.
The pressure sensor 1 is attached to, for example, an engine that is an internal combustion engine such as a vehicle, detects a combustion pressure of the internal combustion engine, and outputs a sensor output corresponding to the combustion pressure to the outside.
As shown in FIG. 1, the pressure sensor 1 includes a housing 6, a diaphragm 2, a cover 4, and a terminal 7. The housing 6 is formed in a substantially cylindrical shape having a hollow portion penetrating in the axial direction. The housing 6 includes a male thread portion 10 for fastening the pressure sensor 1 to a female thread portion provided on the engine body, a small-diameter portion 6a, a large-diameter portion 6b, and a contact portion 9 that comes into contact with a sensor mounting portion of the engine body. Having.
For convenience of explanation, the upper part of FIG. 1 is defined as the upper side in the axial direction of the pressure sensor 1, and the lower part of FIG. 1 is defined as the lower side in the axial direction. Therefore, the male screw portion 10 is provided on the upper side of the housing 6 in the axial direction, and the contact portion 9 is provided on the lower side of the housing 6 in the axial direction. As shown, the contact portion 9 is an inclined surface that tapers downward in the axial direction from the large-diameter portion 6b toward the small-diameter portion 6a.

The cover 4 is formed to have substantially the same diameter as the small-diameter portion 6a of the housing 6, and has a cylindrical shape having a hollow portion penetrating in the axial direction inside. The cover 4 is a member that holds the high-rigidity fixing portion 3c of the pressure transmission rod 3 at the distal end of the housing 6 on the lower side in the axial direction. The pressure transmission rod 3 (see FIGS. 2 and 3) is accommodated in substantially the entire area in the longitudinal direction of the cover 4 and in the small diameter portion 6a of the housing 6.
The diaphragm 2 is attached to an end of the cover 4 on the opposite side to the housing 6 in the axial direction, that is, to an axially lower end of the cover 4. A hole through which the tip of the lower side in the axial direction passes is provided. The diaphragm 2 is formed of, for example, a metal such as Inconel or SUS630.
The terminal portion 7 is attached to an end of the housing 6 opposite to the side of the diaphragm 2 in the axial direction, in other words, to an upper end of the housing 6 in the axial direction. The terminal unit 7 is provided with a terminal unit (not shown) for connecting the pressure sensor 1 to an external electronic device. The terminal unit 7 is supplied with a sensor output output from the pressure detection unit 5. The signal line 8 (see FIG. 3) is connected.

先端 The distal end of the pressure transmission rod 3 at the lower end in the axial direction is fixed to the inner wall of the axially lower through hole of the diaphragm 2 by welding or the like. The diaphragm 2 receives a combustion pressure of the engine, deforms a portion between the fixed portion with the cover 4 and the fixed portion with the pressure transmission rod 3, and applies a compressive force to the pressure transmission rod 3; A function of preventing internal combustion gas from entering the pressure sensor 1.

A pressure detection unit 5 is provided on the pressure transmission rod 3. The pressure transmission rod 3 generates distortion within a range including the installation position of the pressure detection unit 5 according to the compression force received from the diaphragm 2. The distortion of the pressure transmission rod 3 is detected by the pressure detection unit 5. That is, the pressure transmission rod 3 functions as a pressure transmission mechanism that transmits the combustion pressure of the engine to the pressure detection unit 5. The pressure detector 5 is configured using, for example, a strain gauge or the like. The pressure detection unit 5 detects the combustion pressure of the engine by detecting the distortion of the pressure transmission rod 3, and outputs a pressure signal according to the detection result to the terminal unit 7 via the signal line 8. This pressure signal is output from the terminal section 7 to the outside of the pressure sensor 1 as a sensor output.
Note that the pressure detection unit 5 may include a circuit unit that performs analog amplification or digital conversion of a weak signal obtained from a strain gauge or the like, or detects temperature and performs temperature correction. Further, a circuit that generates a sensor output by performing signal processing such as output adjustment on the pressure signal obtained from the pressure detection unit 5 and outputs the sensor output to the outside may be provided in the terminal unit 7.

FIG. 4 is a sectional view of a main part of the pressure sensor shown in FIG.
The pressure transmitting rod 3 includes a pressure transmitting section 3a, an element installation section 3b, a high rigidity fixing section 3c, and an asymmetric rigid section 3d.
The pressure transmitting section 3a is provided at a position located inside the engine with respect to the element installation section 3b and the high rigidity fixing section 3c when the pressure sensor 1 is attached to the engine. The pressure transmitting rod 3, that is, the pressure transmitting portion 3a has a central axis O in the pressure transmitting direction, and transmits the compressive force received from the diaphragm 2 to the element installation portion 3b. That is, the high rigidity fixing portion 3c of the pressure transmission rod 3 is restrained by the housing 6, and functions as a load bearing portion that bears a load due to the combustion pressure. The pressure transmitting rod 3 is deformed by the axial force received by the pressure transmitting section 3a, for example, as shown in FIG. 6, and the output of the pressure detecting section 5 of the element installation section 3b fluctuates according to the amount of deformation. Calibration data of the pressure in the combustion chamber and the output of the pressure detector 5 is created in advance, and the pressure can be detected from the output of the pressure detector 5.
In the following description, the direction orthogonal to the central axis O of the pressure transmitting rod 3 (hereinafter, also simply referred to as “central axis O”) is referred to as x direction, and as shown in FIG. The right side is the + x direction, and the left side of the center axis O is the −x direction.

The element mounting portion 3b has a lower rigidity than the high-rigidity fixing portion 3c, and is a portion that generates a strain according to the compressive force transmitted from the pressure transmitting portion 3a. As shown in FIG. 5B, in the embodiment, the element mounting portion 3b is formed in a semicircular cross-sectional shape in which a part of the pressure transmitting portion 3a having a circular cross section is cut, and the element mounting portion 3b has a flat surface. Is formed. The element installation surface 21 extends in parallel with the central axis O of the pressure transmission rod 3. The pressure detector 5 is fixed on the element installation surface 21. The amount of distortion of the installation part of the pressure detection part 5 in the element installation part 3b is detected by the pressure detection part 5. The amount of distortion is a value corresponding to the combustion pressure of the engine. Although the element mounting surface 21 is illustrated in FIG. 4 as a configuration arranged on the same plane as the central axis O of the pressure transmitting rod 3, the element mounting surface 21 is The plane may be a plane parallel to the central axis O further deviated in the + x direction side, or may be a plane extending in the −x direction side similarly.

The high-rigidity fixing portion 3c has a cross-sectional area of a plane perpendicular to the axial direction which is the central axis O of the pressure transmission direction set to be larger than the element installation portion 3b, and has higher rigidity than the element installation portion 3b. The high rigidity fixing portion 3c has a function of receiving the compressive force transmitted from the pressure transmitting portion 3a and maximizing the amount of distortion in the element installation portion 3b. A through hole 22 that penetrates in the axial direction of the central axis O of the pressure transmitting rod 3 (hereinafter, may be simply referred to as “axial direction”) is formed at the center side of the high rigidity fixing portion 3c. The signal line 8 connected to the pressure detection unit 5 extends through the through hole 22 of the high rigidity fixing unit 3 c and is connected to the terminal unit 7.
The high-rigidity fixing portion 3c includes a large-diameter portion 23 sandwiched between the housing 6 and the cover 4, a small-diameter portion 23a fitted to the housing 6, and a small-diameter portion 23b fitted to the cover 4. . The high-rigidity fixing portion 3 c is configured such that the upper surface of the outer peripheral edge of the large-diameter portion 23 is in contact with the lower end of the housing 6, and the lower surface of the large-diameter portion 23 is in contact with the upper end of the cover 4. Held between.

The asymmetric rigid portion 3d is deviated by a predetermined amount toward the + x direction side from the center axis O by cutting a part of an outer peripheral side of the pressure transmitting portion 3a provided at a position located inside the engine with respect to the pressure detecting portion 5. It is recessed so as to form a plane parallel to the central axis O at the specified position. The asymmetric rigid part 3d makes the rigidity of the pressure transmitting part 3a with respect to the central axis O asymmetric.

FIG. 5A is a diagram illustrating one region of each of the element installation portion and the asymmetric rigid portion in FIG. 4, and FIG. 5B is a diagram with respect to the central axis of the pressure transmission rod in a region IIb of FIG. FIG. 5C is a schematic diagram illustrating a high rigidity side and a low rigidity side, and FIG. 5C is a schematic diagram illustrating a high rigidity side and a low rigidity side with respect to a center axis of the pressure transmission rod in a region IIc of FIG. .
The element mounting portion 3b is cut on the −x side with respect to the central axis O. For this reason, as shown in FIG. 5B, the rigidity of the element mounting portion 3b is greater on the + x direction side of the central axis O than on the −x direction side of the central axis O. In other words, the element installation section 3b has a high rigidity side on the + x direction side from the central axis O and a low rigidity side on the −x direction side from the central axis O.
The pressure transmitting portion 3a is cut on the + x side with respect to the central axis O. For this reason, as shown in FIG. 5C, the pressure transmitting portion 3a has greater rigidity on the −x direction side than the central axis O than on the x direction side of the central axis O. In other words, the pressure transmitting portion 3a has a high rigidity side on the −x direction side from the central axis O and a low rigidity side on the + x direction side from the central axis O. Therefore, the relative arrangement of the high rigidity side and the low rigidity side of the asymmetric rigid part 3d in the direction orthogonal to the axial direction of the pressure transmitting rod 3 is based on the pressure transmission on the high rigidity side and the low rigidity side of the element installation part 3b. The relative arrangement in the direction orthogonal to the axial direction of the rod 3 is opposite to the center axis O of the pressure transmission rod 3.

FIG. 6A is a diagram illustrating a deformed state of the pressure transmission rod in a pressure receiving state of a comparative product having no asymmetric rigid portion, and FIG. 6B is a diagram illustrating a pressure receiving rod of the first embodiment of the present invention. FIG. 4 is a diagram illustrating a deformed state of the pressure transmission rod in the state.
In the pressure transmitting rod 3R without the asymmetric rigid portion 3d shown in FIG. 6A, the element installation portion 3b has the high rigidity side on the + x side and the low rigidity side on the -x side with respect to the center axis O. is there. Therefore, the pressure transmitting portion 3a of the pressure transmitting rod 3R is bent such that the element mounting portion 3b is located inside. When receiving a pulse-like pressure wave of a frequency of about 20 kHz, such as knocking, the pressure transmitting rod 3R deforms as shown in FIG. 6A, and then the state before deformation due to the elasticity of the pressure transmitting portion 3a. Try to return to When the frequency of the pressure wave is close to the natural frequency of the pressure transmission rod 3R, vibration occurs. As shown in FIG. 6A, the vibration induced in the pressure transmitting rod 3R causes the connecting portion 31 between the string formed by the pressure transmitting portion 3a and the element installation portion 3b and the high rigidity fixing portion 3c to be connected. This is a transverse wave vibration mode with the antinode in the vicinity of the center of the pressure transmitting portion 3a. This vibration mode has a low natural frequency, and when receiving a pressure wave including a high frequency component such as knocking, the vibration is induced to cause a measurement error.

In the pressure transmitting rod 3 according to the first embodiment of the present invention shown in FIG. 6B, an asymmetric rigid portion 3d is provided on the pressure transmitting portion 3a connected in the axial direction of the central axis O of the element installation portion 3b. Have been. The pressure transmission rod 3 can be regarded as a beam inserted between the high rigidity fixed portion 3c and the tip of the pressure transmission portion 3a that receives pressure from the diaphragm 2. In the cross section of the pressure transmitting portion 3a where the asymmetric rigid portion 3d is provided, the -x side with respect to the central axis O is the high rigidity side, and the + x side is the low rigidity side. For this reason, the pressure transmitting portion 3a provided with the asymmetric rigid portion 3d bends so as to bend with the asymmetric rigid portion 3d inside. For this reason, the pressure transmission rod 3 is deformed such that the element installation surface 21 of the element installation section 3b is curved inside and the asymmetric rigid portion 3d of the pressure transmission section 3a is curved inside. That is, as shown in FIG. 6B, a vibration mode having two antinodes near the element installation part 3b and near the asymmetric rigid part 3d is induced in the pressure transmission rod 3. This vibration mode has a shorter natural wavelength than the vibration mode induced by the structure of FIG. As a result, even when receiving a pulse pressure of a pressure wave including a high-frequency component such as knocking, vibration is hardly induced, and detection accuracy can be improved.

FIG. 7 shows the amount of strain detected when a pressure wave (20 kHz) is applied. FIG. 7 (a) shows the response of a comparative product having no asymmetrical rigid portion shown in FIG. 6 (a). FIG. 7B is a characteristic diagram, and FIG. 7B is a response characteristic diagram of the present embodiment.
In the pressure transmission rod 3R of the comparative example having no asymmetric rigid portion shown in FIG. 6A, when receiving a pressure wave of 20 kHz generated by knocking or the like, the distortion amount is as shown in FIG. 7A. It appears as a vibration waveform having a relatively large amplitude, and this vibration continues even if it exceeds 500 μs.
On the other hand, in the pressure transmitting rod 3 according to the first embodiment of the present invention, the amplitude of the vibration immediately after receiving the pressure wave of 20 kHz is, as shown in FIG. It is smaller than 3R, and attenuates to an almost negligible size in about 300 μs after receiving the pressure. Thus, it was confirmed that the pressure transmission rod 3 of the first embodiment of the present invention can reduce the vibration after receiving the pressure wave of 20 kHz as compared with the pressure transmission rod 3R of the comparative product. . Thus, it was confirmed that the pressure sensor according to the first embodiment of the present invention reduces measurement errors due to vibration of a transverse wave generated when receiving a pressure wave, and improves detection accuracy.
The resonance frequency of the pressure transmission rod 3R of the comparative product was approximately 20 KHz, but the resonance frequency of the pressure transmission rod 3 according to the first embodiment was about 60 KHz, which is sufficiently higher than 20 KHz.

According to the first embodiment, the following effects can be obtained.
(1) The pressure sensor 1 includes a diaphragm 2, a pressure transmission rod 3 having an element installation part 3b and a pressure transmission part 3a, and a pressure detection part 5 provided at an installation position of the element installation part 3b. The pressure transmission rod 3 is pressed by a pressure wave transmitted through the diaphragm 2 at a position different from the installation position where the pressure detection unit 5 is installed in the axial direction of the pressure transmission rod 3 which is the central axis O of the pressure transmission direction. The transmission rod 3 has an asymmetrical rigid portion 3d for increasing the resonance frequency of the vibration generated. For this reason, even if a pressure wave containing a high-frequency component is transmitted to the pressure transmission rod 3, vibration is less likely to be induced, and detection accuracy can be improved.

(2) The cross section of the pressure transmitting rod 3 where the element installation portion 3b and the asymmetric rigid portion 3d are provided respectively has a high rigidity side and a low rigidity side, and the high rigidity side and the low rigidity of the asymmetric rigid portion 3d. The relative arrangement in the direction orthogonal to the axial direction of the pressure transmitting rod 3 is relatively high in the direction orthogonal to the axial direction of the pressure transmitting rod 3 on the high rigidity side and the low rigidity side of the element installation portion 3b. The arrangement is opposite to the central axis O of the pressure transmission rod 3. Such an asymmetric rigid portion 3d can be formed by cutting a part of the pressure transmission rod 3, for example, and can be efficiently produced.

In the first embodiment, the asymmetric rigid portion 3d is exemplified as a structure formed by cutting a part of the pressure transmitting portion 3a. However, there are various methods and structures other than those described above for forming the asymmetric rigid portion 3d. Hereinafter, those embodiments will be described.

-Second embodiment-
FIG. 8 shows a second embodiment of the pressure sensor of the present invention. FIG. 8A is a cross-sectional view of a main part including an element installation part and an asymmetric rigid part, and FIG. 8A is a schematic diagram illustrating a high rigidity side and a low rigidity side of a region VIIIb, and FIG. 8C is a schematic diagram illustrating a high rigidity side and a low rigidity side of a region VIIIc in FIG.
In the second embodiment, as shown in FIG. 8A, the asymmetric rigid portion 3d of the pressure transmitting rod 3 has a structure provided on the −x side with respect to the central axis O. The pressure transmitting portion 3a according to the second embodiment has the diameter of the pressure transmitting portion 3a of the first embodiment shown in FIG. 5 reduced throughout the longitudinal direction, and a projection called an asymmetric rigid portion 3d having a small outer peripheral surface. In the predetermined axial direction region. By adopting such a shape, as in the first embodiment, asymmetry of rigidity in the axial direction of the pressure transmitting rod 3 is realized.

In the second embodiment, the asymmetric rigid portion 3d is formed integrally with the pressure transmitting portion 3a, and is formed as a projecting portion that further projects in the −x direction from the −x side surface of the pressure transmitting portion 3a. Have been. Therefore, in the direction orthogonal to the central axis O, the pressure transmitting portion 3a has a cross-sectional area of the region where the asymmetric rigid portion 3d on the −x side of the central axis O is provided, in other words, the rigidity is + x more than the central axis O. The cross-sectional area of the region where the side asymmetric rigid portion 3d is not provided, in other words, is larger than the rigidity. That is, the asymmetric rigid part 3d makes the rigidity of the pressure transmitting part 3a with respect to the central axis O asymmetric.

As shown in FIG. 8B, the element mounting portion 3b has a high rigidity side on the + x direction side from the central axis O and a low rigidity side on the −x direction side from the central axis O, as in the first embodiment. is there.
As shown in FIG. 8C, the pressure transmitting portion 3a is provided with an asymmetrical rigid portion 3d on the −x side with respect to the central axis O to increase the sectional area from the central axis O. Therefore, the pressure transmitting portion 3a has a greater rigidity on the −x direction side than the central axis O than on the + x direction side of the central axis O. In other words, the asymmetric rigid portion 3d makes the rigidity of the pressure transmitting portion 3a with respect to the central axis O asymmetric. In the cross section where the asymmetric rigid portion 3d of the pressure transmitting portion 3a is provided, the -x direction side of the central axis O is closer to the -x direction. It is on the high rigidity side, and the + x direction side from the center axis O is the low rigidity side.

Therefore, also in the second embodiment, the relative arrangement in the direction orthogonal to the axial direction of the pressure transmission rod 3 on the high rigidity side and the low rigidity side in the cross section where the asymmetric rigid part 3d of the pressure transmitting part 3a is provided. Is opposite to the relative arrangement of the high rigidity side and the low rigidity side of the element installation portion 3b in the direction orthogonal to the axial direction of the pressure transmission rod 3 with respect to the center axis O of the pressure transmission rod 3. Therefore, as in the first embodiment, a vibration mode with two antinodes near the element installation part 3b and near the asymmetric rigid part 3d is induced in the pressure transmission rod 3. This vibration mode has a shorter natural wavelength than the vibration mode induced in the pressure transmission rod 3 having no asymmetric rigid portion 3d, and thus has a higher natural frequency.
Other configurations in the second embodiment are the same as those in the first embodiment.
Therefore, the second embodiment also has the same effect (1) as the first embodiment. Further, the asymmetric rigid portion 3d in the second embodiment can be formed by integral molding together with the pressure transmitting portion 3a, and has the same effect (2) as the first embodiment. In the second embodiment, the pressure transmitting portion 3a is cut to form the asymmetric rigid portion 3d. The pressure transmitting portion 3a is cut to form the asymmetric rigid portion 3d. The manufacturing cost is higher than in the first embodiment. Can be expected to be further reduced.

-Third embodiment-
9A and 9B show a third embodiment of the pressure sensor of the present invention. FIG. 9A is a sectional view of a main part including an element installation part and an asymmetric rigid part, and FIG. 9B is a sectional view of FIG. 9A is a schematic diagram illustrating a high rigidity side and a low rigidity side of a region IXb, and FIG. 9C is a schematic diagram illustrating a high rigidity side and a low rigidity side of a region IXc in FIG.
In the third embodiment, the asymmetric rigid portion 3d is formed as a low rigidity region in which a part of the pressure transmitting portion 3a of the pressure transmitting rod 3 is formed of a low rigidity material.
As shown in FIG. 9A, the asymmetric rigid portion 3d is formed on the + x direction side of the central axis O. In the third embodiment, the pressure transmitting portion 3a is formed by quenching the entirety of the pressure transmitting portion 3a except for the asymmetric rigid portion 3d, and performing a process of not quenching only the asymmetric rigid portion 3d.
That is, in order to quench the pressure transmitting portion 3a, the entire pressure transmitting portion 3a is heated to an appropriate temperature. At this time, the region where the asymmetric rigid portion 3d is formed is quenched by taking measures such as cooling. Keep below temperature. In this state, when the entire pressure transmitting portion 3a is rapidly cooled and quenched, only the asymmetric rigid portion 3d is not quenched, and has a lower rigidity than other regions of the pressure transmitting portion 3a. Note that, for example, SUS630 or the like can be used as a material of the pressure transmitting unit 3a that performs quenching.

As shown in FIG. 9B, in the element installation part 3b, as in the first embodiment, the + x direction side from the center axis O is on the high rigidity side, and the −x direction side from the center axis O is on the low rigidity side. is there.
The pressure transmitting portion 3a is provided with a non-hardened asymmetric rigid portion 3d on the + x side from the center axis O. Therefore, in the cross section of the pressure transmitting portion 3a where the asymmetric rigid portion 3d is provided, as shown in FIG. 9C, the rigidity on the −x direction side from the central axis O is higher than the + x direction side on the central axis O. large. In other words, the asymmetric rigid portion 3d makes the rigidity of the pressure transmitting portion 3a with respect to the central axis O asymmetric, and the cross section of the pressure transmitting portion 3a where the asymmetric rigid portion 3d is provided is on the −x direction side of the central axis O. It is on the high rigidity side, and the + x direction side from the center axis O is the low rigidity side.

Therefore, also in the third embodiment, the relative positions in the direction orthogonal to the axial direction of the pressure transmission rod 3 on the high rigidity side and the low rigidity side in the cross section where the asymmetric rigid part 3d is provided in the pressure transmitting part 3a. The arrangement is opposite to the central arrangement O of the pressure transmission rod 3 on the high rigidity side and the low rigidity side of the element installation part 3b in the direction orthogonal to the axial direction of the pressure transmission rod 3. . Therefore, as in the first embodiment, a vibration mode with two antinodes near the element installation part 3b and near the asymmetric rigid part 3d is induced in the pressure transmission rod 3. This vibration mode has a shorter natural wavelength than the vibration mode induced in the pressure transmission rod 3 having no asymmetric rigid portion 3d, and thus has a higher natural frequency.

In the above, the step of heating the pressure transmitting unit 3a to the quenching temperature except for a part of the pressure transmitting unit 3a may be such that the pressure transmitting unit 3a is selectively heated using a laser. In the above description, the structure in which only the asymmetric rigid portion 3d which is a part of the pressure transmitting portion 3a is not quenched, but the remaining portion of the pressure transmitting portion 3a is quenched. However, the asymmetric rigid portion 3d may be formed by quenching the entire pressure transmitting portion 3a and then selectively tempering using a laser or the like.

Other configurations in the third embodiment are the same as those in the first embodiment.
Therefore, the third embodiment also has the same effect (1) as the first embodiment. Further, the asymmetric rigid portion 3d in the third embodiment can be formed by not selectively quenching the pressure transmitting portion 3a, and has the same effect (2) as in the first embodiment. ). In the first embodiment, the pressure transmitting portion 3a is cut to form the asymmetric rigid portion 3d. However, in the third embodiment, the asymmetric rigid portion 3d is formed only by locally providing quenching selectivity. Can be formed. For this reason, it can be expected that the manufacturing cost is further reduced as compared with the first embodiment.

-Fourth embodiment-
FIG. 10 shows a fourth embodiment of the pressure sensor of the present invention. FIG. 10 (a) is a sectional view of a main part including an element installation part and an asymmetric rigid part, and FIG. 10 (b) is a sectional view of FIG. 10A is a schematic diagram illustrating a high rigidity side and a low rigidity side of a region Xb, and FIG. 10C is a schematic diagram illustrating a high rigidity side and a low rigidity side of a region Xc in FIG.
In the fourth embodiment, the asymmetric rigid portion 3d is formed such that a part of the pressure transmitting portion 3a of the pressure transmitting rod 3 is a high rigid region formed of a high rigid material.
As shown in FIG. 10A, the asymmetric rigid portion 3d is formed on the −x direction side of the central axis O. In order to increase the rigidity of a part of the pressure transmitting portion 3a, the pressure transmitting portion 3a is locally quenched using, for example, a laser to form an asymmetric rigid portion 3d.

As shown in FIG. 10B, the element installation portion 3b has the high rigidity side on the + x direction side from the central axis O and the low rigidity side on the −x direction side from the central axis O, as in the first embodiment. is there.
The pressure transmitting portion 3a is provided with a hardened asymmetric rigid portion 3d on the −x side from the center axis O. Therefore, in the cross section of the pressure transmitting portion 3a where the asymmetric rigid portion 3d is provided, as shown in FIG. 10 (c), the rigidity on the −x direction side from the central axis O is higher than the + x direction side on the central axis O. large. In other words, the asymmetric rigid portion 3d makes the rigidity of the pressure transmitting portion 3a with respect to the central axis O asymmetric. In the cross section where the asymmetric rigid portion 3d of the pressure transmitting portion 3a is provided, the -x direction side of the central axis O is closer to the -x direction. It is on the high rigidity side, and the + x direction side from the center axis O is the low rigidity side.

Therefore, also in the fourth embodiment, the relative arrangement in the direction orthogonal to the axial direction of the pressure transmission rod 3 on the high rigidity side and the low rigidity side in the cross section where the asymmetric rigid part 3d is provided in the pressure transmitting part 3a. Is opposite to the relative arrangement in the direction orthogonal to the axial direction of the pressure transmitting rod 3 on the high rigidity side and the low rigidity side of the element installation portion 3b with respect to the central axis O of the pressure transmitting rod 3. Therefore, as in the first embodiment, a vibration mode with two antinodes near the element installation part 3b and near the asymmetric rigid part 3d is induced in the pressure transmission rod 3. This vibration mode has a shorter natural wavelength than the vibration mode induced in the pressure transmission rod 3 having no asymmetric rigid portion 3d, and thus has a higher natural frequency.
Other configurations in the fourth embodiment are the same as those in the first embodiment.
Therefore, the fourth embodiment also has the same effect (1) as the first embodiment. Further, the asymmetric rigid portion 3d in the fourth embodiment can be formed by quenching the entire pressure transmitting portion 3a and then selectively tempering the same, and has the same effect as that of the first embodiment ( Perform 2). In the first embodiment, the pressure transmitting portion 3a is cut to form the asymmetric rigid portion 3d. However, in the fourth embodiment, the asymmetric rigid portion is formed only by locally giving temper selectivity. 3d can be formed. For this reason, it can be expected that the manufacturing cost is further reduced as compared with the first embodiment.

-Fifth embodiment-
FIG. 11 shows a fifth embodiment of the pressure sensor of the present invention. FIG. 11A is a cross-sectional view of a main part including an element installation part and an asymmetric rigid part, and FIG. 11A is a schematic diagram illustrating a high rigidity side and a low rigidity side of a region XIb, and FIG. 11C is a schematic diagram illustrating a high rigidity side and a low rigidity side of a region XIc in FIG.
In the fifth embodiment, as shown in FIG. 11A, similarly to the second embodiment shown in FIG. 8A, the asymmetric rigid portion 3d of the pressure transmission rod 3 is connected to the center axis O with respect to the center axis O. It has a structure provided on the x side. However, the asymmetric rigid portion 3d is not a structure integrally formed with the pressure transmitting portion 3a shown in the second embodiment, but a pressure transmitting portion in which the pressure transmitting portion 3a has the same small diameter as in the third embodiment. The portion 3a is provided with a member (hereinafter, referred to as a rigidity improving material) that exerts a rigidity improving function as a separate member. The rigidity improving material may be any material that can be fixed to the pressure transmitting portion 3a and substantially increases the rigidity of the pressure transmitting portion 3a, such as glass, ceramics, and metal.
The rigidity improving material is a semi-annular member provided on a half circumference of the outer peripheral surface of the small diameter pressure transmitting portion 3a.
In the fifth embodiment, the asymmetric rigid portion 3d includes a rigidity improving material fixed to the pressure transmitting portion 3a, and the rigidity improving material has a small diameter in the −x direction on the outer peripheral surface of the pressure transmitting portion 3a. It is formed as a semi-ring-shaped protrusion that protrudes further in the −x direction from the outer peripheral surface. Therefore, in the cross section where the asymmetric rigid portion 3d is provided in the pressure transmitting portion 3a, the cross-sectional area of the region where the asymmetric rigid portion 3d is provided on the −x side of the central axis O in the direction orthogonal to the central axis O is paraphrased. In this case, the rigidity is greater than the rigidity, in other words, the sectional area of the region on the + x side of the central axis O where the asymmetric rigid portion 3d is not provided. That is, the asymmetric rigidity portion 3d including the rigidity improving material and the rigidity with respect to the central axis O of the pressure transmitting portion 3a are made asymmetrical.

As shown in FIG. 11B, the element mounting portion 3b has a high rigidity side on the + x direction side from the central axis O and a low rigidity side on the −x direction side from the central axis O, as in the first embodiment. is there.
As shown in FIG. 11 (c), the pressure transmitting portion 3a is provided with an asymmetric rigid portion 3d including a rigidity improving material for increasing the cross-sectional area from the central axis O on the −x side from the central axis O. I have. For this reason, in the cross section of the pressure transmitting portion 3a where the asymmetric rigid portion 3d is provided, the rigidity on the −x direction side from the central axis O is higher than the + x direction side on the central axis O, as shown in FIG. large. In other words, the asymmetric rigid portion 3d makes the rigidity of the pressure transmitting portion 3a with respect to the central axis O asymmetric. In the cross section where the asymmetric rigid portion 3d of the pressure transmitting portion 3a is provided, the -x direction side of the central axis O is closer to the -x direction. It is on the high rigidity side, and the + x direction side from the center axis O is the low rigidity side.

Therefore, also in the fifth embodiment, the relative positions in the direction orthogonal to the axial direction of the pressure transmission rod 3 on the high rigidity side and the low rigidity side in the cross section where the asymmetric rigid portion 3d is provided in the pressure transmitting portion 3a. The arrangement is opposite to the central arrangement O of the pressure transmission rod 3 on the high rigidity side and the low rigidity side of the element installation part 3b in the direction orthogonal to the axial direction of the pressure transmission rod 3. . Therefore, as in the first embodiment, a vibration mode with two antinodes near the element installation part 3b and near the asymmetric rigid part 3d is induced in the pressure transmission rod 3. This vibration mode has a shorter natural wavelength than the vibration mode induced in the pressure transmission rod 3 having no asymmetric rigid portion 3d, and thus has a higher natural frequency.
Other configurations in the fifth embodiment are the same as those in the first embodiment.
Therefore, the fifth embodiment also has the same effect (1) as the first embodiment. Further, the asymmetric rigid portion 3d in the fifth embodiment can be manufactured only by fixing the rigidity improving material to the pressure transmitting portion 3a. For this reason, the same effect (2) as in the first embodiment is achieved. In the fifth embodiment, the pressure transmitting portion 3a is cut to form an asymmetric rigid portion 3d. The pressure transmitting portion 3a is cut to form an asymmetric rigid portion 3d. The manufacturing cost is higher than in the first embodiment. Can be expected to be further reduced.

-Sixth embodiment-
FIG. 12 shows a sixth embodiment of the pressure sensor of the present invention. FIG. 12 (a) is a sectional view of a main part including an element installation part and an asymmetric rigid part, and FIG. 12 (b) is a sectional view of FIG. 12A is a schematic diagram illustrating a high rigidity side and a low rigidity side of a region XIIb, and FIG. 12C is a schematic diagram illustrating a high rigidity side and a low rigidity side of a region XIIc in FIG.
In the sixth embodiment, the central axis O ₁ of the contact portion of the pressure transmitting portion 3a with the diaphragm 2 is shifted in the −x direction from the central axis O of the entire pressure transmitting portion 3a, and this is defined as an asymmetric rigid portion 3d. .
In this structure, the central axis O ₁ of the contact portion where the pressure transmitting portion 3a contacts the diaphragm 2 is shifted from the central axis O of the entire pressure transmitting portion 3a toward the −x direction, that is, toward the pressure detecting portion 5. As a result, when pressure is applied, the asymmetric rigid portion 3d is deformed so as to be curved with the side opposite to the pressure detecting portion 5 inside as viewed from the central axis of the entire pressure transmitting portion 3a.

As shown in FIG. 12 (b), the element installation portion 3b has a high rigidity side on the + x direction side from the central axis O and a low rigidity side on the −x direction side from the central axis O, as in the first embodiment. is there.
The central axis O ₁ of the contact portion of the pressure transmitting portion 3a with the diaphragm 2 is shifted by a predetermined amount from the central axis O of the entire pressure transmitting portion 3a toward the −x direction. Compressive force in the combustion pressure transmitting portion 3a through the diaphragm 2 is receiving is transmitted to the pressure transmitting portion 3a as an axial force around the center axis O ₁ of the contact portion between the diaphragm 2 of the pressure transmitting portion 3a . For this reason, as shown in FIG. 12C, the rigidity with respect to the central axis O is -x direction side from the central axis O where the central axis O ₁ of the contact portion of the pressure transmitting portion 3a with the diaphragm 2 is set. Is larger than the central axis O on the + x direction side. In other words, in the sixth embodiment, the center axis O ₁ of the contact portion between the diaphragm 2 of the pressure transmitting portion 3a, by deviating from the center axis O of the total pressure transmitting portion 3a, asymmetric rigid portion 3d is constituted . Therefore, also in the sixth embodiment, the asymmetric rigid portion 3d makes the rigidity of the pressure transmitting portion 3a with respect to the central axis O asymmetric. In the structure shown in FIG. 12, the pressure transmitting portion 3a has a high rigidity side on the −x direction side from the central axis O and a low rigidity side on the + x direction side from the central axis O.

As described above, also in the sixth embodiment, the portion that functions as the asymmetric rigid portion 3d in the pressure transmission rod 3 is located on the apparent high rigidity side and low rigidity side in the cross section in the axial direction of the pressure transmission rod 3. The relative arrangement in the direction orthogonal to the relative arrangement in the direction orthogonal to the axial direction of the pressure transmission rod 3 on the high rigidity side and the low rigidity side of the element installation portion 3b is the central axis of the pressure transmission rod 3. The opposite is true for O. Therefore, as in the first embodiment, a vibration mode with two antinodes near the element installation part 3b and near the asymmetric rigid part 3d is induced in the pressure transmission rod 3. This vibration mode has a shorter natural wavelength than the vibration mode induced in the pressure transmission rod 3 having no asymmetric rigid portion 3d, and thus has a higher natural frequency.
Other configurations in the sixth embodiment are the same as those in the first embodiment.
Therefore, the sixth embodiment also has the same effect (1) as the first embodiment. Further, in the sixth embodiment, the center axis O ₁ of the contact portion between the diaphragm 2 of the pressure transmitting portion 3a, asymmetric rigid portion 3d only shifted in the pressure detecting portion 5 side from the center axis O of the total pressure transmitting portion 3a Can be formed. Therefore, the sixth embodiment also has the same effect (2) as the first embodiment. In the sixth embodiment, since it is not necessary to cut the pressure transmitting portion 3a, the pressure transmitting portion 3a that forms the asymmetric rigid portion 3d by cutting the pressure transmitting portion 3a is formed by cutting the pressure transmitting portion 3a. It can be expected that the manufacturing cost is further reduced as compared with the first embodiment in which 3d is formed.

-Seventh embodiment-
FIG. 13 shows a seventh embodiment of the pressure sensor of the present invention. FIG. 13 (a) is a sectional view of a main part including an element installation part and an asymmetric rigid part, and FIG. 13 (b) is a sectional view of FIG. 13A is a schematic diagram illustrating a high rigidity side and a low rigidity side of a region XIIIb, and FIG. 13C is a schematic diagram illustrating a high rigidity side and a low rigidity side of a region XIIIc in FIG.
In the seventh embodiment, the asymmetric rigid portion 3d has a structure provided in the high rigidity fixing portion 3c.
The asymmetric rigid portion 3d is provided on the + x direction side of the central axis O of the high rigidity fixing portion 3c. The asymmetric rigid portion 3d is provided by cutting a part on the outer peripheral side of the high rigidity fixing portion 3c on the −x side with respect to the central axis O. That is, the asymmetric rigid part 3d makes the rigidity of the high rigidity fixing part 3c with respect to the central axis O asymmetric.

As shown in FIG. 13 (b), the element installation part 3b has a high rigidity side on the + x direction side from the central axis O and a low rigidity side on the −x direction side from the central axis O, as in the first embodiment. is there.
As shown in FIG. 13C, the high rigidity fixing portion 3c is cut on the + x side with respect to the central axis O. Therefore, in the section where the asymmetric rigid portion 3d is provided in the high rigidity fixing portion 3c, as shown in FIG. 13C, the −x direction side from the central axis O is more rigid than the x direction side from the central axis O. Is big. In other words, in the high rigidity fixing portion 3c, the −x direction side from the central axis O is the high rigidity side, and the + x direction side from the central axis O is the low rigidity side. Accordingly, the relative arrangement of the high rigidity side and the low rigidity side of the section provided with the asymmetric rigid portion 3d in the high rigidity fixing portion 3c in the direction orthogonal to the axial direction of the pressure transmission rod 3 is the same as that of the element installation portion 3b. The relative arrangement of the high rigidity side and the low rigidity side in the direction orthogonal to the axial direction of the pressure transmitting rod 3 is opposite to the center axis O of the pressure transmitting rod 3.

For this reason, in the pressure transmission rod 3, as in the first embodiment, a vibration mode with two antinodes near the element installation part 3b and near the asymmetric rigid part 3d provided on the high rigidity fixing part 3c is induced. Is done. This vibration mode has a shorter natural wavelength than the vibration mode induced in the pressure transmission rod 3 having no asymmetric rigid portion 3d, and thus has a higher natural frequency.
Other configurations in the seventh embodiment are the same as those in the first embodiment.
Therefore, the seventh embodiment also has the same effect (1) as the first embodiment. Further, the asymmetric rigid portion 3d in the seventh embodiment can be formed by cutting a part of the high rigidity fixing portion 3c. Therefore, the seventh embodiment also has the same effect (2) as the first embodiment.

In the first to sixth embodiments, inside the engine body, the pressure detecting unit 5 is provided closer to the outside of the engine body than the asymmetric rigid part 3d provided in the pressure transmitting unit 3a. On the other hand, in the seventh embodiment, inside the engine body, the pressure detector 5 is provided closer to the engine combustion chamber than the asymmetric rigid portion 3d provided in the high rigidity fixing portion 3c. For this reason, in the seventh embodiment, the length from the contact portion of the pressure transmission rod 3 with the diaphragm 2 to the pressure detection portion 5 where the compressive force is transmitted as compared with the first to sixth embodiments, that is, , The transmission path length becomes shorter. Therefore, the transmission loss of the compressive force in the transmission path can be reduced. Thus, the seventh embodiment also has an effect that the pressure detection sensitivity can be improved as compared with the first to sixth embodiments. Further, since the length of the transmission path through which the compressive force of the diaphragm 2 is transmitted to the pressure detection unit 5 is reduced, the effect of improving the responsiveness is also achieved.

However, in the seventh embodiment, since the pressure detection unit 5 is close to the engine combustion chamber, heat inside the engine is easily transmitted to the pressure detection unit 5. For this reason, the temperature rise of the pressure detection unit 5 increases, and the possibility of output fluctuation, damage to the pressure detection element, and the like increases. That is, in the seventh embodiment and the first to sixth embodiments, there is a trade-off relationship between the pressure detection sensitivity and the responsiveness and the temperature rise of the pressure detection unit. It is preferable to select according to the situation.

-Eighth embodiment-
FIG. 14 shows an eighth embodiment of the pressure sensor of the present invention. FIG. 14 (a) is a cross-sectional view of a main part including an element installation part and an asymmetric rigid part, and FIG. 14 (b) is a sectional view of FIG. 14A is a schematic diagram illustrating a high rigidity side and a low rigidity side of a region XIVb, and FIG. 14C is a schematic diagram illustrating a high rigidity side and a low rigidity side of a region XIVc of FIG.
In the eighth embodiment, a structure in which an element installation surface 21 of the element installation unit 3b on which the pressure detection unit 5 is installed and one surface 24 of the pressure transmitting unit 3a are flush with each other in a direction orthogonal to the central axis O. Having.
The element installation surface 21 of the element installation part 3b and one surface 24 of the pressure transmitting part 3a are located on the −x side of the central axis O. A surface of the element installation portion 3b opposite to the element installation surface 21 is partially cut to form a groove 3f. That is, the groove 3f is provided on the + x side of the central axis O. The bottom surface of the groove 3f is provided near the same plane as the central axis O. However, the position of the bottom surface of the groove 3f may be shifted to the + x side or the -x side from the center axis O. The asymmetric rigid portion 3d is provided on the −x side of the central axis O by cutting a part of the pressure transmitting portion 3a.

The element installation portion 3b is cut on the + x side with respect to the central axis O, and a groove 3f is formed. Therefore, as shown in FIG. 14B, the element installation section 3b has a high rigidity side on the −x direction side from the central axis O and a low rigidity side on the + x direction side from the central axis O, as shown in FIG.
The pressure transmitting portion 3a has an asymmetric rigid portion 3d in which the -x side is cut with respect to the central axis O. Therefore, in the cross section of the pressure transmitting portion 3a where the asymmetric rigid portion 3d is provided, as shown in FIG. 14C, the + x direction side from the central axis O is the high rigidity side, and the − direction side from the central axis O is the negative side. On the low rigidity side. Therefore, the relative arrangement of the high rigidity side and the low rigidity side in the cross section of the pressure transmitting portion 3a where the asymmetric rigid portion 3d is provided in the direction orthogonal to the axial direction of the pressure transmitting rod 3 is the height of the element installation portion 3b. The relative arrangement of the rigid side and the low rigidity side in the direction orthogonal to the axial direction of the pressure transmitting rod 3 is opposite to the center axis O of the pressure transmitting rod 3.

Other configurations in the eighth embodiment are the same as those in the first embodiment.
Therefore, the eighth embodiment has the same advantages (1) and (2) as the first embodiment.
In the eighth embodiment, one surface 24 of the pressure transmitting unit 3a is provided at the same height in the direction orthogonal to the central axis O as the element installation surface 21 of the element installation unit 3b on which the pressure detection unit 5 is installed. ing. For this reason, in the joining step of joining the pressure detecting section 5 to the element installation section 3b and the connecting step of connecting the signal line 8 to the pressure detecting section 5, it becomes easy to insert the tip of the jig or the robot. For this reason, the workability can be improved, and the jig and the robot tip structure can be simplified, and the manufacturing cost can be reduced.

-Ninth embodiment-
15A and 15B show a ninth embodiment of the pressure sensor of the present invention. FIG. 15A is a cross-sectional view of a main part including an element installation part and an asymmetric rigid part, and FIG. 15A is a schematic diagram illustrating a high rigidity side and a low rigidity side of a region XVb of FIG. 15A, and FIG. 15C is a schematic diagram illustrating a high rigidity side and a low rigidity side of a region XVc of FIG. FIG. 15D is a schematic diagram showing the high rigidity side and the low rigidity side of the region XVd in FIG. 15A.
The ninth embodiment has a structure in which _two asymmetric rigid portions 3d ₁ and 3d ₂ are provided in the pressure transmitting portion 3a.
The pressure transmitting portion 3a is formed slightly longer in the axial direction than the pressure transmitting portion 3a of the first to eighth embodiments, and the two asymmetric rigid portions 3d ₁ and 3d ₂ do not overlap in the axial direction. Position.
Asymmetric rigid portion 3d ₁ is disposed at a position closer to the element mounting portion 3b in the axial direction, the + direction of the central axis O, is provided by cutting a part of the outer peripheral side of the pressure transmitting portion 3a. Asymmetric rigid portion 3d ₂ is located closer to the diaphragm 2 in the axial direction, of the center axis O - direction side, is provided by cutting a part of the outer peripheral side of the pressure transmitting portion 3a.

As shown in FIG. 15B, the element installation portion 3b has a high rigidity side on the + x direction side from the central axis O and a low rigidity side on the −x direction side from the central axis O, as in the first embodiment. is there.
As shown in FIG. 15 (c), in the region XVc of the pressure transmitting portion 3a asymmetric rigid portion 3d ₁ is provided, -x direction from the center axis O is high rigid side, from the + x direction is the center axis O On the low rigidity side. Further, as shown in FIG. 15 (d), in the region of the pressure transmitting portion 3a asymmetric rigid portion 3d ₂ is provided XVd, the central axis O + x direction is high rigid side, -x from the center axis O The direction side is the low rigidity side.

In the ninth embodiment, the high rigidity side and low-rigidity side of the asymmetric rigid portion 3d ₁ provided the cross-section in the pressure transmitting portion 3a, the relative arrangement in the direction perpendicular to the axial direction of the pressure transmission rod 3, element The relative arrangement of the high rigidity side and the low rigidity side of the installation portion 3b in the direction orthogonal to the axial direction of the pressure transmission rod 3 is opposite to the center axis O of the pressure transmission rod 3. Further, in the ninth embodiment, the high rigidity side and low-rigidity side in a cross section asymmetric rigid portion 3d ₂ of the pressure transmitting portion 3a is provided, in the direction perpendicular to the axial direction of the pressure transmission rod 3, relative arrangement, the high-rigidity side and low-rigidity side in a cross section asymmetric rigid portion 3d ₁ of the pressure transmitting portion 3a is provided, the relative arrangement in the direction perpendicular to the axial direction of the pressure transmission rod 3, the pressure transmission rod 3 with respect to the central axis O. Accordingly, in the ninth embodiment, the vibration mode of the belly three near and around the asymmetric rigid portion 3d ₂ element mounting portion 3b and around the asymmetric rigid portion 3d ₁ is induced. This vibration mode has a shorter natural wavelength than the vibration mode having no asymmetric rigid portion 3d, and thus has a higher natural frequency. As a result, even if a pressure wave including a high-frequency component such as knocking is received, vibration is hardly induced, and detection accuracy can be improved.

Other configurations in the ninth embodiment are the same as those in the first embodiment.
Therefore, the ninth embodiment also has the same effects (1) and (2) as the first embodiment.

で は In the ninth embodiment, the pressure transmitting portion 3a is formed slightly longer in the axial direction than the pressure transmitting portion 3a of the first to eighth embodiments. In other words, the pressure detector 5 is installed at a position distant from a combustion chamber such as an engine. Thereby, the heat in the combustion chamber transmitted to the pressure detecting unit 5 during use is suppressed. For this reason, it is possible to suppress the temperature rise of the pressure detection unit 5 and suppress the output fluctuation of the pressure detection unit 5 or use an inexpensive pressure detection element having low heat resistance.

Normally, when the axial length of the pressure transmitting portion 3a is increased, the wavelength of the induced vibration mode is increased, and the natural frequency is reduced. For this reason, when receiving a pressure wave including a high frequency component such as knocking, a vibration mode is induced, and a measurement error occurs. However, in the ninth embodiment, the vibration modes that can be induced by the asymmetric rigid portions 3d ₁ and 3d ₂ provided at two locations are set to the wavelengths with the antinodes at the three locations of the element installation portion 3b and the asymmetric rigid portion 3d. Since the length can be shortened, a decrease in the natural frequency can be suppressed. As a result, even when a pressure wave including a high frequency component such as knocking is received, a vibration mode is not induced, and a measurement error can be suppressed.
In the ninth embodiment, the structure in which the asymmetric rigid portions 3d ₁ and 3d ₂ are provided in two places is exemplified, but a structure in which three or more asymmetric rigid portions are provided may be adopted.

-Tenth embodiment-
16A and 16B show a pressure sensor according to a tenth embodiment of the present invention. FIG. 16A is a cross-sectional view of a main part including an element installation part and an asymmetric rigid part, and FIG. 16A is a schematic diagram illustrating a high rigidity side and a low rigidity side of a region XVIb, and FIG. 16C is a schematic diagram illustrating a high rigidity side and a low rigidity side of a region XVIc of FIG. In the tenth embodiment, a cut surface 3g is provided on the element installation portion 3b on the opposite side of the element installation surface 21 on which the pressure detection unit 5 is installed, and a part of the cut surface 3g is different from the first embodiment. Is cut to form a groove 3h.

Since the cut surface 3g is formed by cutting the opposite side of the element installation surface 21 on which the pressure detection unit 5 of the element installation unit 3b is installed in the first embodiment, the element installation unit 3b is formed as in the first embodiment. The thickness (the length in the x direction) is smaller than in the case. That is, the region XVId of the element installation portion 3b is a thin portion made thinner than the other region XVIb of the element installation portion 3b. As a result, the overall rigidity of the pressure transmitting rod 3 in the cross section where the element installation portion 3b is provided is lower than that in the first embodiment, and the amount of distortion in the pressure detection unit 5 increases. Can be improved. The groove 3h of the element installation portion 3b is provided by further cutting from the cut surface 3g to the center axis O side. The groove 3h of the element installation portion 3b is provided near the boundary with the high rigidity fixing portion 3c.

In the region XVIb where the groove 3h of the element installation part 3b is not provided, although the thickness of the element installation part 3b is thinner than in the first embodiment, the arrangement of the high rigidity side and the low rigidity side with respect to the center axis O changes. As shown in FIG. 16B, as in the first embodiment, the + x direction side from the central axis O is the high rigidity side, and the −x direction side from the central axis O is the low rigidity side, as in the first embodiment. .
In the region XVIc where the asymmetric rigid portion 3d of the pressure transmitting portion 3a is provided, as shown in FIG. 16C, the −x direction side from the center axis O is the high rigidity side, as in the first embodiment. The + x direction side from the center axis O is the low rigidity side. Although not shown, in the region XVId in the cross section in which the groove 3h is provided in the element mounting portion 3b, the + x direction side from the center axis O is the high rigidity side, and the −X side from the center axis O, as in FIG. The x direction side is the low rigidity side.

Therefore, the relative arrangement in the direction orthogonal to the axial direction of the pressure transmission rod 3 on the high rigidity side and the low rigidity side where the asymmetric rigid part 3d is provided in the pressure transmission part 3a is determined by the element installation part in the pressure transmission rod 3. The relative arrangement in the direction orthogonal to the axial direction of the pressure transmission rod 3 on the high rigidity side and the low rigidity side in the cross section provided with 3 b is opposite to the central axis O of the pressure transmission rod 3.

Other configurations in the tenth embodiment are the same as those in the first embodiment.
Therefore, the tenth embodiment also has the same advantages (1) and (2) as the first embodiment.

The groove 3h of the element installation portion 3b is provided near the boundary with the high rigidity fixing portion 3c. The groove 3h of the element installation part 3b is provided at a position farthest from the combustion chamber of the engine in the axial direction of the element installation part 3b. Thereby, the pressure detection sensitivity is further improved.
The reason why the pressure detection sensitivity is improved by the groove 3h will be described below with reference to FIG.

FIG. 17 is a diagram showing a deformed state of the pressure transmission rod in the pressure receiving state shown in FIG.
In the tenth embodiment, when pressure is received, the pressure transmission rod 3 is curved with the element installation surface 21 inside in the region XVIb where the groove 3h of the element installation portion 3b is not provided, and the pressure transmission rod 3 The region XVIc is deformed so as to be curved with the asymmetric rigid portion 3d inside. In the tenth embodiment, unlike the first embodiment, a groove 3h is provided on the high rigidity fixing portion 3c side of the element installation portion 3b. The region XVId of the element installation portion 3b provided with the groove 3h is thinner in the x direction than the region XVIb of the element installation portion 3b not provided with the groove 3h, and has a lower rigidity. For this reason, the region XVId of the element installation portion 3b provided with the groove 3h is curved with the groove 3h inside. Therefore, the axial length of the deformation region of the element installation section 3b that is curved with the element installation section 3b inside is reduced by the groove 3h. For this reason, the curvature of the deformation of the element installation portion 3b that curves inward is reduced. That is, the pressure transmission rod 3 of the tenth embodiment in which the groove 3h is provided on the high rigidity fixing portion 3c side of the element installation portion 3b is different from the pressure transmission rod 3 of the first embodiment in which the groove 3h is not provided. When the pressure wave is received, the element mounting portion 3b bends so that the curvature thereof becomes small. For this reason, the amount of distortion generated in the range including the installation position of the pressure detection unit increases, and the pressure detection sensitivity improves.
That is, according to the tenth embodiment, the effects (1) and (2) of the first embodiment are exhibited, and in particular, the effect of further improving the pressure detection sensitivity is exhibited.

The pressure sensor of the present invention can be applied to a pressure sensor that detects a pressure other than the combustion pressure of an internal combustion engine such as an engine.

Although various embodiments have been described above, the present invention is not limited to these embodiments. The above embodiments may be combined or modified, and other modes that can be considered within the scope of the technical idea of the present invention are also included in the scope of the present invention.

The disclosure of the following priority application is incorporated herein by reference.
Japanese patent application 2018-157703 (filed on August 24, 2018)

1 the pressure sensor 2 diaphragm 3 pressure transmitting rod 3a pressure transmitting portion 3b element mounting portion 3c highly rigid fixing part _3d, 3d 1, 3d ₂ asymmetric rigid portion 3e improved rigidity member 3f groove 3g cut surface 3h groove 5 the pressure sensing portion 21 element mounting Surface O Central axis of pressure transmitting rod O ₁ Central axis of contact part between pressure transmitting part and diaphragm

Claims (15)

1. A diaphragm for receiving pressure,
   An element installation portion, and a pressure transmission rod having a pressure transmission portion provided between the diaphragm and the element installation portion,
   A pressure detection unit provided at an installation position of the element installation unit of the pressure transmission rod,
   A pressure sensor that detects and outputs distortion generated within a range including the installation position of the pressure detection unit according to a compression force received from the diaphragm,
   The pressure transmission rod is provided with a pressure wave transmitted through the diaphragm at a position different from the installation position where the pressure detection unit is installed in the axial direction of the pressure transmission rod, which is a central axis of a pressure transmission direction. A pressure sensor having an asymmetric rigid portion for increasing a resonance frequency of vibration generated in a pressure transmission rod.
2. The pressure sensor according to claim 1, wherein
   The element mounting portion and the asymmetric rigid portion each have a high rigidity side and a low rigidity side,
   The relative arrangement of the high-rigidity side and the low-rigidity side in the cross section of the pressure transmission rod provided with the asymmetric rigid portion in the direction orthogonal to the axial direction of the pressure transmission rod is as follows. The relative arrangement of the high-rigidity side and the low-rigidity side in the cross section provided with the element installation portion in the direction orthogonal to the axial direction of the pressure transmission rod is opposite to the center axis of the pressure transmission rod. Pressure sensor.
3. The pressure sensor according to claim 2, wherein
   A pressure sensor in which the pressure transmission rod is curved as an antinode protruding in a direction opposite to each part provided with the element installation part and the asymmetric rigid part.
4. The pressure sensor according to claim 3, wherein
   The pressure transmission rod is provided on the opposite side of the diaphragm side in the axial direction of the pressure transmission rod from the installation position where the pressure detection unit is installed, and has high rigidity higher than the element installation unit. A pressure sensor having a fixed part.
5. The pressure sensor according to claim 2, wherein
   A pressure sensor in which a cut portion formed by partially removing the pressure transmission rod is provided as the asymmetric rigid portion on the low rigidity side of the cross section of the pressure transmission rod where the asymmetric rigid portion is provided. .
6. The pressure sensor according to claim 5, wherein
   The pressure sensor is provided in the pressure transmitting unit.
7. The pressure sensor according to claim 2, wherein
   A pressure sensor having a low-rigidity region in which the pressure-transmitting rod is partially reduced in rigidity on the low-rigidity side of a cross section of the pressure-transmitting rod where the asymmetric rigid portion is provided.
8. The pressure sensor according to claim 7, wherein
   The low-stiffness region is a pressure sensor formed by performing a process of reducing a part of the pressure transmitting unit to have a lower rigidity than another region.
9. The pressure sensor according to claim 2, wherein
   A pressure sensor in which a high-rigidity region in which the pressure transmission rod is partially high-rigidity is provided on the high-rigidity side of the asymmetric rigid portion.
10. The pressure sensor according to claim 9, wherein
    The high-rigidity area is a pressure sensor formed by performing a high-rigidity process on a part of the pressure transmitting unit.
11. The pressure sensor according to claim 2, wherein
    The pressure sensor wherein the asymmetric rigid portion is formed by shifting a center of a contact portion between the pressure transmitting portion and the diaphragm with respect to the central axis of the pressure transmitting rod.
12. The pressure sensor according to claim 2, wherein
    The pressure sensor is provided at a plurality of different positions in the axial direction of the pressure transmitting rod, wherein the asymmetric rigid portion is provided.
13. The pressure sensor according to claim 1, wherein
    The pressure sensor having a thin portion formed by removing a part of the element installation part on a side opposite to an installation surface on which the pressure detection part is provided.
14. The pressure sensor according to any one of claims 1 to 13, wherein:
    The pressure sensor, wherein the asymmetric rigid portion is provided on the diaphragm side in the axial direction of the pressure transmission rod with respect to the installation position of the pressure detection portion.
15. The pressure sensor according to any one of claims 1 to 13, wherein:
    The pressure sensor, wherein the asymmetric rigid portion is provided on the opposite side of the diaphragm side in the axial direction of the pressure transmission rod from the installation position of the pressure detection portion.

Images