JPH0624754Y2 - Washer pressure sensor - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a washer-type pressure sensor which is fixed to a detected part and detects its pressure by a piezoelectric phenomenon.

[Conventional technology]

Fig. 3 shows an example of a conventional washer-type pressure sensor (actually developed 59-
FIG. 10 is a cross-sectional view showing the configuration of Japanese Patent No. 108244).

First, the structure of the conventional washer-type pressure sensor 1 will be described. A ring-shaped first pressure receiving plate 4 made of metal, and a metal or non-metal second pressure receiving plate 5 similarly formed in a ring shape. Are concentrically opposed to each other, and two ring-shaped piezoelectric elements 6 and 7 are closely laminated on both surfaces of the electrode plate 8 between these two pressure receiving plates 4 and 5. Then, the inner peripheral portion of the central hole of the first pressure receiving plate 4 is extended to the second pressure receiving plate 5 side to form the tubular protective portion 11, and the tubular protective portion 11 and the piezoelectric elements 6 and 7 are formed. A tubular insulating material 9 made of plastic, fluororubber or the like is interposed therebetween, and the end portion 16 of the tubular protection portion 11 is swaged so as to wrap around the inner peripheral portion 26 of the second pressure receiving plate 5, 1,
The second pressure receiving plates 4 and 5, the electrode plate 8 and the piezoelectric elements 6 and 7 are sandwiched and held under pressure. The piezoelectric elements 6 and 7 are set in advance so as to have the same polarity toward the electrode plate 8. Therefore, the first and second pressure receiving plates 4 and 5 and the electrode plate 8 have different polarities. . Reference numeral 2 denotes an output terminal provided on a part of the outer periphery of the electrode plate 8, and a shielded cable or the like is spot-welded to the output terminal 2 so that the electromotive force from the piezoelectric elements 6 and 7 is guided to the outside.

On the other hand, the outer peripheries of the first and second pressure receiving plates 4 and 5, the electrode plate 8 and the piezoelectric elements 6 and 7 are molded with an insulating fixing material 10 such as synthetic resin, and integrally formed in a washer mold as a whole. ing.

FIG. 4 shows a partial sectional shape of each member constituting the washer pressure sensor 1.

The washer pressure sensor 1 having such a structure is, for example,
As shown in FIG. 5, the step portion 15a of the ignition plug 15 which is tightened and inserted into the cylinder head 12 of the automobile engine.
It is fixed on the ignition plug insertion port 14 by being interposed between the cylinder head 12 and the cylinder head 12, and the change in the tightening pressure from the screw portion 15b of the ignition plug 15 due to the combustion of gas is detected to detect the inside of the combustion chamber 13. It is used to measure the gas pressure of.

[Problems to be solved by the invention]

However, in such a conventional washer-type pressure sensor, since the output terminal of the electrode plate is fixed only by the insulating fixing material, a tensile load is applied from the shielded cable connected to the output terminal. If a bending load is continuously applied to the output terminal, the output terminal breaks due to metal fatigue.

The present invention has been made in view of such conventional problems, and an object thereof is to provide a washer pressure sensor in which the mechanical strength of an output terminal is improved.

[Means for solving problems]

And in order to achieve this purpose, the present invention provides:
A ring-shaped electrode plate (8), an output terminal (2) is formed on a part of the outer periphery of the electrode plate (8), at least one or more piezoelectric elements (7) and a pair of pressure receiving plates (4). , 5) are sequentially laminated and integrally molded with an insulating fixing material (10), wherein at least one pressure receiving plate (4 or 5) of the pair of pressure receiving plates (4, 5) is used. A holding plate (19) for holding the output terminal (2) is formed by extending a part of the outer periphery, and the holding plate (19) has ends of the output terminal (2) and the output cable (25). Is pressure-bonded by at least one pressing plate (22) and integrally fixed, and the outside of the pressure sensor in the fixed state is integrally molded by the insulating fixing material (10).

[Action]

 The operation of the present invention will be described.

A holding plate (19) is formed by extending a part of the outer periphery of at least one of the pair of pressure receiving plates (4,5) to form the holding plate (1).
9) The output terminal (2) and the output cable (25) are integrally fixed with each other, and the outer peripheral portion of the pressure sensor in the fixed state is integrally molded with the insulating fixing material (10). The holding plate (19) receives a tensile load or a bending load applied from a shielded cable or the like connected to the output terminal (2) and the output terminal (2) and the output cable (2).
5) Protect weak points, such as connection points with, and prevent failures such as disconnection.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of a washer pressure sensor according to an embodiment of the present invention.

First, the configuration will be described. Basically, the structure is substantially the same as the structure of the conventional washer-type pressure sensor 1 described in FIG. 3, but a holding plate 19 is provided on a part of the outer circumference of the first pressure receiving plate 4, and the holding plate 19 is attached to the holding plate 19. The difference is that the output terminal 2 is firmly fixed. The holding plate 19 is composed of a plate 21 provided by extending the outer peripheral portion of the first pressure receiving plate 4 and pressing plates 22 and 23. Reference numeral 25 is a shielded cable that guides the electromotive force from the piezoelectric elements 6 and 7 to the outside, and includes a core wire 25a, an insulator 25b,
It is composed of a braid 25c. Reference numeral 10 is an insulating fixing material. Reference numeral 24 is an insulating tube made of Teflon that covers the output terminal 2. The end portion 28 of the output terminal 2 is located substantially in the middle of the holding plate 22, the end portion 28 and the core wire 25a of the shield cable 25 are connected by spot welding, and the holding plate is provided via an insulating tube 27 made of Teflon. It is firmly crimped with 22 and fixed. Further, the pressing plate 23 firmly crimps and fixes the braid 25c of the shielded cable 25 in contact therewith. Therefore, the first pressure receiving plate 4 is grounded via the braid 25c. Finally, the outer peripheral portion of the washer pressure sensor 30 which is connected and fixed in this way is integrally molded into the washer mold with the insulating fixing material 10.

In the washer pressure sensor 30 having the above structure, the output terminal 2 is firmly fixed by the pressing plate 22 even if a tensile load or a bending load is applied from the shielded cable 25 or the like connected to the output terminal 2, and Shielded cable 2
Since 5 is also firmly fixed by the pressing plate 23, no load is applied to the output terminal 2.

FIG. 2 is a sectional view showing the structure of a washer pressure sensor 29 according to another embodiment of the present invention. First, the structure will be described.

The washer pressure sensor 29 is basically similar in structure to the washer pressure sensor 30 described with reference to FIG. 1, but in the present embodiment, the first piezoelectric element 6 and the pressing plate are used. 23 is omitted to have a simple structure.

The holding plate 19 is composed of a plate 21 provided by extending the outer peripheral portion of the first pressure receiving plate 4 and a holding plate 22. Reference numeral 31 is an insulating plate that insulates the pressure receiving plate 7 from the electrode plate 8. Reference numeral 32 is a partition plate in which the insulating plate 31 is extended outward, and ensures insulation between the plate 21 provided on a part of the outer peripheral portion of the pressure receiving plate 4 and the output terminal 2. An insulating band 33 is formed integrally with the partition plate 32. The end 28 of the output terminal 2 is located near the middle of the holding plate 22, the end 28 and the core wire 25a of the shielded cable 25 are connected by spot welding, and the insulating band 33 is connected to the output terminal 2. 2 and core wire 2
It is wound around 5a and is firmly fixed by the pressing plate 22. Finally, the holding plate 1 fixed in this way
9, the outer peripheral portion of the piezoelectric element 7 and the pressure receiving plate 7 is an insulating fixing material 1
0 to mold integrally.

Even in the washer pressure sensor 29 configured as described above, even if a tensile load or a bending load is applied to the output terminal 2 from the shielded cable or the like connected to the output terminal 2, the output terminal 2 is securely held by the pressing plate 22. Since it is fixed, no load is applied to the output terminal 2.

[Effect of device]

A holding plate (19) is formed by extending a part of the outer periphery of at least one of the pair of pressure receiving plates (4,5) to form the holding plate (1).
Since the output terminal (2) and the output cable (25) are integrally fixed by 9) and the outer peripheral portion of the pressure sensor in the fixed state is integrally molded by the insulating fixing material (10), the output terminal (2) The holding plate (19) can receive a tensile load or a bending load applied from a shielded cable or the like connected to the output terminal (2) and the output terminal (2) and the output cable (25). It can protect weak points such as connection points and prevent failures such as disconnection.

As a result, the number of parts and the number of processing steps can be reduced, the cost can be reduced, and the yield can be improved.

This makes it possible to provide a washer-type pressure sensor that is inexpensive and can improve the mechanical strength of the output terminal (2).

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure of a washer pressure sensor according to an embodiment of the present invention, FIG. 2 is a sectional view showing a structure of a washer pressure sensor according to another embodiment, and FIG. 3 is a conventional washer. FIG. 4 is a cross-sectional view showing the configuration of the mold pressure sensor, FIG. 4 is a cross-sectional view showing the shapes of the components of the washer pressure sensor shown in FIG. 3, and FIG. 5 is a usage example of the washer pressure sensor. 1, 29, 30 …… washer type pressure sensor 2 …… Output terminals 4,5 …… Pressure plate 6,7 …… Piezoelectric element 8 …… Electrode plate 9 …… Insulation material 10 …… Insulation fixing material 19 …… Holding plate 21 ...... Plate 22, 23 ...... Presser plate 25 ...... Shield cable (output cable) 27 ...... Insulation tube

Claims (1)

[Scope of utility model registration request] 1. A ring-shaped electrode plate (8), and an output terminal (2) formed on a part of the outer periphery of the electrode plate (8),
At least one or more piezoelectric elements (7) and a pair of pressure receiving plates (4, 5) are sequentially laminated and an insulating fixing material (10)
In the washer-type pressure sensor integrally molded with the output terminal (2), a part of the outer circumference of at least one pressure receiving plate (4 or 5) of the pair of pressure receiving plates (4, 5) is extended. A holding plate (19) for holding the output terminal (2) and the output cable (25) is crimped to the holding plate (19) by at least one holding plate (22) to integrally form the holding plate (19). A washer-type pressure sensor, wherein the pressure sensor outer peripheral portion in a fixed state is integrally molded with the insulating fixing material (10).