JPS6026429Y2 - electronic switch - Google Patents

Description

[Detailed Description of the Invention] This invention relates to electronic switches such as proximity switches and photoelectric switches.

Electronic switches such as proximity switches and photoelectric switches
It is often configured to be housed in a metal case for protection and shielding.

By the way, in general, in electronic devices that directly utilize a commercial AC power source, if the electronic device has a metal case, a grounding terminal must be provided to ground the metal case.

Recently, proximity switches and photoelectric switches are also using methods that use commercial AC power directly as a power source, such as AC 2-wire type,
have come to be widely adopted, and these electronic switches with metal cases also require a grounding terminal.

The general method for grounding these electronic switches is not to directly ground each metal case externally, but to pull the wires of the electronic switch outside together and ground them together with the grounding terminals of other electrical equipment in a relay box. It has been adopted.

Therefore, it is necessary for the ground terminal of these electronic switches to lead out the electric wire or terminal connected to the metal case together with the lead wire or terminal of the electronic switch.

Further, in these electronic switches, the method of connecting conductive wires to the metal case of the electronic switch is extremely limited due to miniaturization and strict requirements for waterproofness.

Conventionally, in order to connect a ground conductor to the metal case of this type of electronic switch, for example, in the case of a proximity switch, as shown in FIG. The metal piece 9 was brought into contact with the ground conductor 4 and the ground conductor 4 was soldered to the metal piece 9.

According to this, there is no need to provide an opening for connecting the conductive wire to the metal case 3, and there is no need to directly solder the metal case 3, resulting in good airtightness and excellent workability.

However, there is a drawback that the reliability of contact between the metal piece 9 and the inner wall of the metal case 3 is low.

Further, as shown in FIG. 2, a hole is provided in the metal case 3, and a ground conductor 4 is passed through the hole and soldered to the outer surface of the metal case 3.

In this case, the heat capacity of the metal case 3 is large, making it difficult to solder. Also, if the metal case 3 is made of aluminum, special soldering materials and soldering work are required, and the soldering surface is not good and the appearance is poor. There was a drawback that it was not good.

In addition, in these Figures 1 and 2, 1 is a coil case, 2 is a sealing rubber, 5 is a cable sealing rubber, and 6 is a coil case.
7 is an internal circuit, and 8 is a lead-out cable.

In view of these circumstances, it is an object of the present invention to provide an improved electronic switch that has good workability and can reliably connect a ground conductor to a metal case.

An embodiment in which the present invention is applied to a proximity switch will be described below with reference to the drawings from FIG. 3 onwards.

As shown in FIG. 3, a cylindrical opening 3 is formed in the metal case 3.
A is provided so that the cylindrical conductor piece 10 can be fitted.

The conductor piece 10 is made of a material suitable for soldering, such as brass, and has a through hole 10a in the center, into which the ground conductor 4 is inserted and soldered. Ru.

The conductor piece 10 thus soldered is press-fitted into the opening 3a of the metal case 3.

In this way, since the ground conductor 4 is soldered to the small cylindrical conductor piece 10 made separately from the metal case 3, the workability of soldering is good.

Further, it is possible to maintain sufficient contact between the metal case 3 and the cylindrical conductor piece 10 by press-fitting and fitting.

Note that the connection between the ground conductor 4 and the conductor piece 10 may be made by providing a through hole 10a as shown in FIG. 3, but as shown in FIG.
Alternatively, the tip may be inserted and soldered.

Further, as shown in FIG. 5, a groove 10c is provided around the outer circumference of the cylindrical conductor piece 10, and an O-ring-shaped seal rubber 11 is fitted into this groove 10c. If the conductor piece 10 is press-fitted and fitted into the opening 3a of No. 3, it is possible to prevent water or the like from entering through the minute gap between the conductor piece 10 and the opening 3a.

As explained in the embodiments above, according to the present invention, the ground conductor is first soldered to a conductor piece separate from the metal case, and this conductor piece is press-fitted into the opening provided in the metal case. As a result, the workability is good and the electrical connection between the ground conductor and the metal case is reliable.

[Brief explanation of the drawing]

Figures 1 and 2 are longitudinal cross-sectional views showing a conventional example, Figure 3 is a vertical cross-sectional view showing an embodiment of the present invention, and Figures 4 and 5 are enlarged views showing a portion of a modified example. FIG. 1... Coil case, 2, 5, 11...
・Seal rubber, 3...Metal case, 4...
...Ground conductor, 6...Cable clamping fitting, 7.
...Internal circuit, 8...Output cable, 9
...Metal piece, 10...Cylindrical conductor piece.

Claims (1)

[Scope of utility model registration request] In an electronic switch in which a circuit section is housed in a metal case, an opening is provided in the metal case, a ground conductor is soldered to a conductor piece separate from the metal case, and this conductor piece is inserted into the metal case. An electronic switch characterized by being press-fitted and mated into an opening.