JPH0328348Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention is a knocking sensor that is attached to a cylinder block, etc., and extracts the vibration as an electrical signal in order to detect knocking in the combustion chamber of an internal combustion engine. Regarding waterproof resin leakage prevention structure.

<Prior art> As a conventional knocking sensor, the one shown in Fig. 5 is known (Utility Model No. 58-180427).
(see publication).

That is, the case 1 has a storage space 1 in which a pair of piezoelectric elements 3 with a lead plate 2 sandwiched therein is stored.
A is formed with an opening. A cover 6 is fixed to the opening of the case 1 by caulking the periphery of the opening of the case 1. In addition, inside the cover 6,
The connector terminal 4 and a part of the lead wire 5 that electrically connects the base end of the connector terminal 4 and the piezoelectric element 3 are embedded by integral molding.

In the storage space 1a, there is a resin 7 for waterproofing.
is filled. Here, as the resin 7, a soft resin such as urethane-based or epoxy-based resin is used, which is liquid at the time of injection and solidifies over time to become rubber-like with elasticity.

In this way, knocking vibrations generated in the combustion chamber of the internal combustion engine are extracted as electrical signals from the piezoelectric element 3 from a connector (not shown) connected to the terminal 4 via the lead wire 5, and knocking in the internal combustion engine is detected. It's on.

<Problems to be solved by the invention> However, in such a conventional knocking sensor, the storage space of the piezoelectric element 3 is filled with waterproof resin 7, but as the resin 7 solidifies, Due to the volumetric expansion, a phenomenon occurs in which unsolidified liquid resin is pushed outward through the gap formed at the boundary between the cover 6, the lead wire 5, and the connector terminal 4, and permeates and leaks. As a result, penetration and
Problems arise in that the leaked resin solidifies near the terminals 4, making it impossible to mate with a mating connector (not shown) or causing a defective electrical connection.

The present invention has been made in view of the problems of the conventional technology, and an object of the present invention is to provide a waterproof resin leakage prevention structure for a knocking sensor that can prevent penetration and leakage of waterproof resin.

<Means for Solving the Problems> For this reason, a case is provided in which the storage space for storing the piezoelectric element is formed with a partially open area, a cover that is attached to the case by closing the opening of the case, and a cover that is attached to the case by closing the opening of the case. A connector terminal whose base end is buried in the cover, a lead wire that electrically connects the connector terminal and the piezoelectric element and is partially buried in the cover, and a storage space closed by the case. and a waterproofing resin filled with the connector terminal, and an elastic sealing member was attached to at least one of the proximal end of the connector terminal and the lead wire so as to surround the outer peripheral wall thereof, and the elastic sealing member was embedded in the cover.

<Function> Since the above configuration is adopted, even if the waterproofing resin is pushed outward through the gap formed at the boundary between the cover and the lead wires and connector terminals, the lead wires and connector terminals The elastic seal member inserted into the container acts as an obstacle to prevent penetration and leakage.

Therefore, there is no possibility that fitting with the mating connector will become impossible or that the electrical connection will become defective.

<Embodiment> FIGS. 1 and 2 show a first embodiment of the present invention. Note that elements similar to those in the conventional example are designated by the same reference numerals as in FIG. 5, and explanations thereof will be omitted.

The cover 6 includes a lead wire 5 to which an elastic seal member 10 is attached surrounding the outer peripheral wall thereof, and a proximal end portion of the connector terminal 4 connected to the lead wire 5.
are buried together.

As shown in FIG. 2, the elastic sealing member 10 has a hole 10a slightly smaller than the outer diameter of the lead wire 5 formed in the center thereof, and has a shape (bellows shape) in which a plurality of conical portions 10b are connected to each other on the outer periphery. ). Then, by fitting the elastic seal member 10 into the lead wire 5, the sealing property with the lead wire 5 is maintained.

Further, the elastic seal member 10 is embedded in the cover 6 so that the large diameter side of the conical portion 10b faces the storage space 1a side, and is slightly compressed by expansion when the resin of the cover 6 solidifies, and is compressed into the cover 6. be made into one. Therefore, the elastic seal member 10 can be elastically brought into contact with the boundary portion with the cover 6, and the sealing performance between the two can be maintained well.

Moreover, the plurality of conical parts 10b on the outer periphery and the cover 10
The boundary formed between the two has a complicated mechanical seal shape, which effectively prevents the waterproofing resin 7 from penetrating and leaking.

With the above configuration, the waterproof resin 7
Even if the cover 6 is pushed outward through the boundary between the lead wire 5 and the connector terminal 4, the elastic seal member 10 prevents penetration and leakage. As a result, it is possible to prevent failure of fitting with the connector and poor electrical connection.

FIG. 3 shows a second embodiment of the present invention.

This is the elastic seal member 1 in the first embodiment.
This is a modified version of 0.

That is, the elastic sealing member 10 has a shape in which a hole 10a for the lead wire 5 is formed as in the first embodiment, and flange portions 10c are formed at both ends of the outer peripheral portion.

This has a mechanical seal shape that is more complicated than that of the second embodiment, and has the effect of preventing penetration and leakage of the waterproofing resin 7 as in the first embodiment, and can prevent the inability to fit the connector and the electrical connection failure.

FIG. 4 shows a third embodiment of the present invention.

This is also a modification of the shape of the elastic seal member 10 in the first embodiment, and the elastic seal member 10 is shaped like a ring in which a hole 10a similar to that in the first embodiment is formed. The same effects as in the above embodiment can be obtained with the elastic seal member 10 having a simple shape, and an increase in cost can be prevented as much as possible.

In addition, in each of the above-mentioned embodiments, the elastic seal member 1
Although the example in which the connector terminal 0 is inserted into the lead wire 5 is shown, it may be provided near the base end of the connector terminal 4 so as to surround the outer peripheral wall thereof. Furthermore, elastic sealing members 10 may be attached to both the lead wires 5 and the connector terminals 4 to completely prevent penetration and leakage of the waterproofing resin.

<Effects of the invention> As explained above, according to the invention, an elastic seal member is attached to at least one of the connector terminal and the lead wire and embedded in the cover, so that the connection between the cover, the lead wire, and the connector terminal is prevented. It is possible to prevent the waterproofing resin from penetrating or leaking through the boundary.

Therefore, the inability to fit the connector and the occurrence of electrical connection failure are prevented.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the first embodiment of the present invention, FIG. 2 is a detailed view of the elastic sealing member of the same as above, FIG. 3 is a detailed view of the elastic sealing member of the second embodiment of the same, and FIG. The figure is a detailed view of the elastic sealing member according to the third embodiment, and FIG. 5 is a sectional view of a conventional knocking sensor. 1... Case, 3... Piezoelectric element, 4... Connector terminal, 5... Lead wire, 6... Cover, 7...
Waterproofing resin, 10...Elastic sealing member.

Claims (1)

[Scope of utility model registration request] A case in which a storage space for storing a piezoelectric element is partially opened, a cover that is attached to the case by closing the opening of the case, and a connector terminal whose base end is buried in the cover. , a knotting comprising: a lead wire that electrically connects the connector terminal and the piezoelectric element and is partially buried in the cover; and a waterproof resin that fills a storage space closed by the case. In the sensor,
A waterproof resin leakage prevention structure for a knocking sensor, characterized in that an elastic sealing member is attached to at least one of the proximal end of the connector terminal and the lead wire so as to surround the outer peripheral wall thereof, and is embedded in the cover.