JPH0421824B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an acceleration detector using a piezoelectric element.

In FIG. 1 showing a conventional acceleration detector of this type, reference numeral 1 denotes a housing member, which has a threaded portion 1a for attachment to an object to be measured, such as an internal combustion engine. 2 is a weight that converts acceleration into stress; 3 is a piezoelectric element made of lead zirgonate titanate or the like that converts stress into electricity; and 4 is an electrode terminal for taking out the electrically converted detection output. Numeral 5 is a screw that fastens the weight 2, piezoelectric element 3, and electrode terminal 4 to the housing member 1, and is insulated by a tube 6. The socket member has an output terminal 9 and a connector portion 8a, and the joint between the socket member 8 and the housing member 1 is waterproofed by an O-ring 10. Reference numeral 11 indicates an O-ring for waterproofing the fitting portion of the connector portion 8a of the socket member 8, and reference numeral 12 indicates a sealing material filled to waterproof the joint portion between the electrode terminal 4 and the output terminal 9. The socket member 8 is integrated with the housing member 1 by a caulking portion 1b that is a part of the housing member 1.

The conventional acceleration detector configured in this way is
The housing member 1 is attached to the threaded portion 1a so as to be accelerated in the same mode as the object to be measured, such as between internal combustion engines. The piezoelectric element 3 placed between the housing member 1 and the weight 2 receives stress in the thickness direction due to the acceleration force applied to the housing member 1 and the inertia force of the weight 2, and generates an acceleration signal proportional to the acceleration. Occur. This acceleration signal generated from the piezoelectric element 3 is output to the outside via an output terminal 9 connected to one end of the electrode terminal 4 placed between the pair of piezoelectric elements 3. Contact between the electrode terminal 4 and the screw 5 and housing member 1 is prevented by the tubes 6 and 7.

Since the piezoelectric element 3 has a high impedance, when placed in a highly concentrated atmosphere, the piezoelectric element 3 has the disadvantage that the output decreases due to charge leakage and the detection sensitivity decreases. Therefore, a waterproof structure is required, and waterproof O-rings 10, 11 and sealing material 1 are required.
2 is required. That is, the O-ring 10 is used to make the joint between the housing member 1 and the socket member 8 waterproof, the O-ring 11 is used to make the fitting part between the socket member 8 and the other external socket waterproof, and the sealing material 12 is filled. By doing so, the opening provided in the socket member 8 for connecting the electrode terminal 4 and the output terminal 9 is made waterproof, and the inside of the acceleration detector and the connector portion 8a are
This keeps the mating part waterproof.

However, among these waterproof measures, 12 sealants
There is a problem with waterproofing by filling. That is, since the sealing material 12 uses a highly airtight resin material such as an epoxy microwave oven, a heating process is required to cure it in a short period of time, which has the drawback of causing a decrease in productivity.

The present invention is intended to solve the above-mentioned problems, and aims to provide an acceleration detector that can obtain good waterproof properties through a simple assembly process.

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 2, 1 is a housing member, 1
a is a screw part, 2 is a waist, 3 is a piezoelectric element, 4 is an electrode terminal, 5 is a screw, 6 and 7 are tubes, 8 is a socket member, 8a is a connector part, 9 is an output terminal,
10 is an O-ring, and 11 is an O-ring. Since these are the same as those shown in FIG. 1, corresponding parts are designated by the same reference numerals and their explanation will be omitted. 13
A support member is disposed between the housing member 1 and the socket member 8 and supports an output terminal 9 connected to the electrode terminal 4. The piezoelectric element 3, electrode terminal 4, and weight 2 are fastened to the housing member 1 with screws 5 in the same manner as in the prior art, and a detection signal is led out from the electrode terminal 4 via the output terminal 9.

FIG. 3 shows a part of the acceleration detector shown in FIG. As is clear from this figure, a large semicircular opening is formed in the support member 13, and the electrode terminal 4 and the output terminal 9 are provided in the opening.
The tip of the electrode terminal 4 passes through a hole 14 provided in the output terminal 9 and is exposed so as to facilitate the connection work with the output terminal 9. The work of connecting the output terminal 9 to this exposed end by soldering is difficult because this part is largely open to the open end side of the housing member 1.
It can be done easily. The support member 13 having this opening is covered by the housing member 1 and the socket member 8 attached thereto. The socket member 8 is integrated with the housing member 1 by a caulking portion 1b, and a support member 13 is sandwiched between the two.

O-ring 10 is housed within the gap formed by housing member 1, socket member 8 and support member 13. Further, the O-ring 11 is attached to the outer periphery of the connector portion 8a of the socket member 8, and when this connector portion and a mating external socket are fitted together, the O-ring 11 waterproofs the fitting portion. In other words, with the mating external socket attached to the connector part 8a, each joint surface of the mating external socket, the O-ring 11, the socket, the member 8, the O-ring 10, and the housing member 1 exhibits a waterproof function, and the acceleration detector The waterproof structure is completed.

As described below, the acceleration detector of the present invention has an opening for soldering an electrode terminal for taking out an acceleration signal detected by the detection element and an output terminal for outputting this acceleration signal to the outside. Since the structure includes a support member that supports the output terminal, and the support member is held between the housing member and the socket member, the electrode terminal and the output terminal can be reliably electrically and physically connected by soldering. For soldering, the opening and the inside of the socket member are sealed by sandwiching the supporting member between the housing member and the socket member. A waterproof effect can be obtained without using a sealant for sealing, simplifying the structure and assembly process, and dramatically improving production.

[Brief explanation of drawings]

Figure 1 is a vertical cross-sectional view of a conventional acceleration detector;
The figure is a longitudinal sectional view of an acceleration detector according to an embodiment of the present invention, and FIG. 3 is a partially cutaway perspective view of the main parts thereof. 1...Housing member, 1a...Threaded part, 1b
... Caulking part, 2 ... Weight, 3 ... Piezoelectric element, 4 ... Electrode terminal, 5 ... Screw, 8 ... Socket member, 8a ... Connector part, 9 ... Output terminal,
10, 11... O ring, 13... Support member, 1
4...hole. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. Accommodating a piezoelectric element, a weight for applying acceleration force to the piezoelectric element, and an electrode terminal for taking out a detection output detected by the piezoelectric element,
A housing member having an attachment part for attaching to the part to be measured, a socket member fixed to the housing member via an O-ring, and an output terminal soldered to the electrode terminal and outputting the detection output to the outside. and a support member that supports the output terminal and has an opening at a soldered portion between the electrode terminal and the output terminal, and the support member is held between the housing member and the socket member. An acceleration detector characterized in that the opening and the inside of the socket member are sealed.