JPH06746Y2 - Gasket type pressure sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention provides an interface between a cylinder head seat surface of an engine and a gasket seat surface of a spark plug that generate vibrations due to combustion pressure of an internal combustion engine, knocking, fuel injection, and the like. The present invention relates to a gasket type pressure sensor which is mounted and detects a pressure fluctuation caused by the vibration by a piezoelectric element.

(Prior Art) As a gasket type pressure sensor of this type, as shown in FIG. 6, the piezoelectric elements 2 and 2 are stacked via an internal electrode plate 3, and a metal spacer 4 on the upper surface and a presser foot 16 on the lower surface. Fitting grooves 16a, 16a are formed on the inner and outer edges of the lower part, and O-rings 17, 17 made of fluororesin are arranged in the fitting groove to improve the sealing property. The one that is tightly wrapped is the actual one 61-60137.
It is known from the publication. It is also known that a presser foot 16 has a resin layer formed by baking a fluororesin on at least the lower inner edge thereof instead of the O-ring.

(Problems to be Solved by the Invention) By the way, in the pressure sensor of the above configuration, the former O
The one using the ring is the O-ring and the fitting groove 1 of the presser foot 16
6A has a defect that cracks are likely to occur when it is inserted into 6a and the sealing property is impaired, and the latter one provided with a fluororesin layer has a defect that the baking work is extremely troublesome and the cost is high.

The present invention solves the above problems, and provides a gasket-type pressure sensor having a simplified structure, easy work, a sealing property inside a metal case, and a reduced cost.

(Means and Actions for Solving Problems) The present invention is designed to press the presser foot into a metal case by accumulating at least one annular piezoelectric element, an internal electrode plate, a presser foot, etc. In a gasket-type pressure sensor that is wrapped, at least one groove that communicates the inner diameter and the outer diameter is formed on the inner surface of the presser foot on the stacking side, and the inner and outer circumferences between the metal case and the integrated body are passed through the groove. Insulating filler such as silicon resin is sealed in the gap of the metal case, and the filler is passed through the take-out mouth of the output lead wire by the groove formed in the presser foot as described above to separate the metal case and the integrated body. Since the gap between the inner and outer circumferences can be filled, the work is easy, the sealing property inside the metal case is maintained, and the insulation between the internal electrode plate and the metal case can be secured.

(Example) Hereinafter, the present invention will be described in detail with reference to an example.

1 and 2 show an embodiment of a gasket type pressure sensor in the case of two piezoelectric elements of the present invention, in which 1 is a metal case made of stainless steel or the like and an annular shape having a U-shaped section in advance. The metal case (4
2Ni-Fe spacers 4 and piezoelectric elements 2 and 2 are laminated via an internal electrode plate 3, and a metal (42N
(i-Fe, etc.) packing is stacked, and a presser foot 6 having an annular groove 6a communicating the inner and outer diameters is arranged so that the groove 6a faces the packing 5, and the metal case 1 The integrated body 10 is wrapped by caulking inward so as to face the opening tip portion. Gaps 7 and 8 are formed on the inner and outer circumferences of the metal case 1 and the piezoelectric elements 2 and 2, the internal electrode plate 3, the spacer 4 and the packing 5. On the other hand, a hole is formed in the outer periphery of the metal case 1 and a base 11 is joined thereto, and an output lead wire 12 connected to the internal electrode plate 3 and insulated is arranged inside the base. A filling material 13 such as a silicon resin is vacuum-filled therein, and at the same time, is filled in the outer peripheral gap 8 and at the same time is filled in the inner peripheral gap 7 through the groove 6a to seal the metal case 1 and the integrated body 10. Property and insulation are maintained. The size of the presser foot is such that it fits loosely in the metal case, and the inner and outer edges of the presser foot may be chamfered or rounded (R).

3 and 4 show the structure of the presser foot 6,
FIG. 3 shows one groove 6a used in FIG.
FIG. 4 shows three grooves 6a provided, and the size and the number (1 to 4) of these grooves are appropriately selected so that the gaps 7 and 8 on the inner and outer circumferences are sufficiently filled with the filler. You can

FIG. 5 shows an embodiment of the present invention having one piezoelectric element, in which a spacer 5, an insulator 9, an internal electrode plate 3, a piezoelectric element 2 and a groove 6a are formed in a metal case 1. The presser foot 6 is laminated to form an integrated body 10, and the integrated body 1 is formed.
The gaps 7 and 8 between 0 and the metal case 1 are filled with a silicone resin filler 13 as in FIG. In the case of such an embodiment, the cost can be reduced because there is one piezoelectric element.

Although the spacer 4 and the packing 5 are used in the above-described embodiment, such a component can be omitted for cost reduction and thinning of the pressure sensor.

(Effect of the Invention) As described above, in the gasket type pressure sensor of the present invention, at least one groove communicating with the inner and outer diameters is formed on the inner surface of the presser foot on the stacking side. It can be easily formed at one time in the gap between the inner and outer circumferences of the integrated body and the sealability to the inside of the metal case and the insulation between the inside of the metal case and the integrated body can be sufficiently maintained, and it has excellent durability. The work is easy and the cost can be reduced.

[Brief description of drawings]

FIGS. 1 and 2 show an embodiment of the present invention in which two piezoelectric elements are used. FIG. 1 is a longitudinal sectional view thereof, FIG. 2 is a partially enlarged longitudinal sectional view of FIG. Fig. 4 and Fig. 4 show an embodiment of a presser foot. Fig. 3 (a) is a front view with one groove, Fig. 3 (b) is a side view thereof, and Fig. 4 is a front view with three grooves. FIG. 5 is a partially enlarged vertical sectional view showing an embodiment in the case of one piezoelectric element of the present invention,
FIG. 6 is a partially enlarged vertical sectional view showing a conventional embodiment. 1 ... Metal case 2 ... Piezoelectric element 3 ... Internal electrode plate 6 ...
Presser foot 6a ... Grooves 7, 8 ... Gap 9 ... Insulator 10 ...
Aggregate 13 ... Filling material

Claims (2)

[Scope of utility model registration request] 1. A gasket-type pressure sensor comprising a metal case and an integrated body in which at least one annular piezoelectric element, an internal electrode plate, a presser foot, and the like are stacked, wrapped in a metal case so as to press the presser foot. Forming at least one groove connecting the inner diameter and the outer diameter on the inner surface of the presser foot on the stacking side,
A gasket-type pressure sensor in which an insulative filler is enclosed in the inner and outer gaps between the metal case and the integrated body through the groove. 2. The gasket type pressure sensor according to claim 1, wherein the filling material is made of a silicone resin.