JPH08723Y2 - Sealed variable resistor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a sealed variable resistor, and more particularly to the shape of an outer case.

[Conventional technology]

Conventionally, as shown in FIG. 3, a hermetically sealed variable resistor has an O-ring 3 made of an elastic material such as silicone rubber interposed at the interface between the outer case 1 and the rotor 2 to shield the outside air.
It is sealed from the outside atmosphere. In addition, a resin 5 is applied to the gap between the outer surface of the alumina substrate 4 and the inner peripheral surface of the outer case 1 to seal it from the external atmosphere, and a sealed variable resistor is obtained.

[Problems to be Solved by the Invention] In the conventional sealed variable resistor described above, a resin having good fluidity such as a thermosetting resin is used for forming the resin 5. That is, a liquid thermosetting resin having fluidity is laid on the alumina substrate 4 and then heated and solidified to form the resin 5. By the way, when the layer of the resin 5 is formed in this way, the resin 5 placed on the alumina substrate 4 loses its fluidity by heating and forms a constant shape until the resin 5 has a constant shape. It may pass through the gap between the peripheral surface and the alumina substrate 4 along the inner peripheral surface of the outer case and hang down to enter the gap between the rotor 2 and the outer case 1.
The resin that has entered between the outer case 1 and the rotor 2 in this manner is then heated and cured at that portion. The conventional sealed variable resistor has the following drawbacks due to the penetration of such resin into the inside.

(1) The resin is interposed between the inner peripheral surface of the outer case and the rotor, and the frictional force between the sliding surfaces of the two increases, so that the rotational torque of the rotor increases.

(2) The outer case and the rotor are fixed to each other by the resin, so that the rotor cannot rotate and slide.

(3) It is necessary to select a resin having a short curing time in order to minimize the sagging of the resin.

The purpose of the present invention is to prevent the resin from dripping on the sliding surface of the outer case against the rotor, which is a drawback of the prior art. As a result, the rotation torque of the rotor is reduced and good rotation can be obtained. Thus, the rotor does not stick to the outer case and the rotor can slide and rotate. Another object of the present invention is to provide a hermetically sealed variable resistor which can use a resin having a long curing time.

[Means for solving the problem]

A hermetically sealed variable resistor according to the present invention comprises a tubular outer case with both bottoms open, a rotor fitted so as to close an opening on one bottom surface of the outer case from the inside, and the other of the outer cases. At least the insulating substrate provided on the bottom side so as to close the open bottom surface, and one bottom side of the outer case has an elastic O-ring between the outer case inner wall and the rotor outer wall. On the other bottom side of the outer case, a resin layer obtained by solidifying and solidifying liquid resin is provided on the outer surface of the insulating substrate so that the rotor is slidable. In the hermetically sealed variable resistor having a sealed structure, the step of moving from the insulating substrate to the rotor on the inner surface of the outer case from the insulating substrate to the rotor is performed. Inward Ri out as a sealed variable resistor, characterized in that the one or more stages stepped at least. Since the resin dripping from the gap between the outer case and the insulating substrate stays in the steps of the stairs, in the sealed variable resistor of this invention, the resin drips on the sliding surface of the outer case with the rotor. Don't go

〔Example〕

Next, the present invention will be described with reference to the drawings. First
FIG. 1 is a sectional view of a sealed variable resistor according to an embodiment of the present invention. Reference numeral 1 in the drawing denotes an outer case, the inner peripheral surface of which is stepped.

The resin 5 has fluidity until it hardens, and the inner peripheral surface of the outer case 1 hangs down from the gap between the inner peripheral surface of the outer case 1 and the alumina substrate 4, but since the resin 5 is stored in the stairs, the outer case 1 The resin does not drip on the sliding surface with the rotor 2.

 FIG. 2 is a sectional view of another embodiment of the present invention.

Reference numeral 1 in the drawing denotes an outer case having an inner peripheral surface formed into a plurality of steps.

In the second embodiment, since a large amount of the resin 5 dripping on the inner peripheral surface of the outer case 1 can be stored by a plurality of steps, even if a resin having a long curing time is used, the outer case 1
The resin does not drip on the sliding surface with the rotor 2.

[Effect of device]

As described above, the present invention can prevent the resin from dripping on the sliding surface of the outer case with the rotor by making the inner peripheral surface of the outer case stepwise, and has the following effects. .

(1) Since the resin does not intervene on the sliding surface of the outer case with the rotor, the rotation torque of the rotor is reduced and good rotation can be obtained.

(2) The rotor does not stick to the outer case, and the rotor can slide and rotate.

(3) It is possible to use a resin having a long curing time.

[Brief description of drawings]

FIG. 1 is a sectional view of a sealed variable resistor which is an embodiment of the present invention, FIG. 2 is a sectional view of another embodiment of the present invention, and FIG. 3 is an example of a conventional sealed variable resistor. FIG. 1 ... Exterior case, 2 ... Rotor, 3 ... O-ring, 4
…… Alumina substrate, 5 …… Resin.

Claims (1)

[Scope of utility model registration request] 1. A cylindrical outer case with both bottom surfaces open, a rotor fitted so as to close an opening on one bottom surface of the outer case from the inside, and an open bottom surface on the other bottom surface side of the outer case. At least one insulative substrate provided so as to close the outer case, and one outer bottom surface side of the outer case is provided with an elastic O-ring between the inner wall of the outer case and the outer wall of the rotor. The other bottom side of the case has a structure in which the rotor is slidable and the inside is hermetically sealed by providing a resin layer obtained by solidifying and solidifying liquid resin on the outer surface of the insulating substrate. In the hermetically-sealed variable resistor, a step overhangs inward of the outer case from the insulative substrate toward the rotor between the insulating substrate on the inner surface of the outer case and the rotor. like, A sealed variable resistor characterized by having at least one step.