JPH0677426B2 - Thermal switch - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention drives a movable contact by utilizing a thermoresponsive plate such as a bimetal or a trimetal that is deformed by a change in temperature, and a fixed contact forming a pair with the movable contact. The present invention relates to a heat-responsive switch that opens and closes an electric current, and is used for protecting a refrigerator or a motor of a hermetic electric compressor such as a room air conditioner.

[Background technology]

Conventionally, as this type of heat responsive switch, a "small electric switch" in Japanese Patent Publication No. 45-40818 and a "motor protection device" shown in Japanese Patent Publication No. 49-24744 are known.
In each case, there was a problem in calibrating to a predetermined temperature at which the heat responsive plate operates. That is, in order to calibrate the temperature to a predetermined temperature, a thermo-responsive plate made of a material such as bimetal is drawn into a shallow dish at approximately the central portion, and the thermo-responsive plate itself has a temperature of, for example, 140 ° C. It changes the bending direction by snapping at ℃, and snaps back to the original bending direction by snapping at a lower temperature, for example, 80 ℃, but as a switch, one end of its thermal response plate is fixed to a stationary member. For example, when a movable contact is fixed to an end and the movable contact and the fixed contact provided in a portion electrically insulated from the stationary member are brought into contact with the movable contact at a predetermined pressure at room temperature. The heat-responsive plate is in a state in which it is easy to reverse with respect to the curved shape. With only the heat-responsive plate alone, the one in which the bending direction is snap-changed at 140 ° C reverses at 130 ° C, for example, and operates in reverse to move from the fixed contact to the movable contact. Snap open It becomes allowed to it to. That is, it is possible to obtain an ideal thermally actuated switch in which the contact operation of the switch has no creep and is performed instantaneously. Here, the calibration of the operating temperature of the thermo-responsive switch means that when the reversal temperature of a single thermo-responsive plate is distributed with a variation of, for example, 135 ° C to 150 ° C for a large number of samples, the inversion temperature of each single thermoresponsive plate is On the other hand, the operating temperature required for the switch, that is, the temperature at which the movable contact snaps apart from the fixed contact is adjusted to, for example, 130 ° C. ± 5 ° C. This process is called the temperature calibration process of the switch.Specifically, since either the member with the fixed contact fixed or the member with the fixed end of the thermal response plate fixed is subject to bending deformation in order to apply the contact pressure, However, since the reversal temperature of each heat-responsive plate is different, the amount of bending deformation is also different, so that the amount of springback of the member subjected to bending deformation is different, which is inaccurate.

[Outline of Invention]

In order to solve the above problems, the present invention provides beam members parallel to each other on both sides of a supporting portion to which a heat responsive plate is fixed in a cantilever shape, and one of the beam members is provided with a calibration piece protruding therefrom. , The other beam member is provided with a support portion for receiving the tip end portion of the calibration piece, and receives the tip end portion of the calibration piece and the support body to which the fixed side opposite to the movable contact side of the heat responsive plate is fixed. By calibrating the temperature with almost no springback, by inserting the calibration piece in a wedge shape between it and the bearing, and stopping at the position where the heat responsive plate operates at a specified temperature, the wedge is inserted. If it is possible, it will happen.

Example of Invention

In FIGS. 1 and 2, reference numeral 1 denotes an elliptic lid plate made of a relatively thick iron plate, and a circular hole is formed substantially in the center thereof.
1A is perforated, and a conductive pin 3 of iron / nickel alloy penetrates through the cover plate 1 and is hermetically sealed and fixed by an electric insulator 2 such as glass. One beam member 5 having a supporting portion 5A of the heat responsive plate 4 and a calibration piece 5B at the left end of the conductive pin 3 in the figure.
C, and the integrated root 5F portion of the other beam member 5E having a support portion 5D for receiving the tip end of the calibration piece 5B is fixed. It is preferable that the left ends of both beam members 5C and 5E shown in the figure are integrated to enhance strength. Further, each of these parts may be integrally formed, or if necessary, each part or part may be separately formed and integrated by welding. For convenience of explanation, the integrated body will be referred to as a holding body 5. The left end of the holding member 5 in the drawing is a stopper portion so that the contact gap when the movable contact 4A is separated from the fixed contact 6A is within a certain range when the heat responsive plate reaches a predetermined temperature and snaps reverse movement.
Has 5G. Stationary That shown right end of the thermally responsive plate 4 is secured by such methods spot welding Purozekushon 5A ₁ to 5A ₅ protruding downward in FIG. 2 to the supporting portion 5A of the holder 5. The movable contact 4A is fixed near the free end of the heat responsive plate 4 by a method such as spot welding, and is arranged so as to come into contact with and separate from the fixed contact 6A. Fixed contact 6A is fixed contact support 6
The metal tip 6B is fixed by welding or the like, and the one closer to the root of the tip 6B has a ceramic joint 6C with a heat-resistant bonding agent 6E, for example, a ceramic having a slightly lower melting point than the joint 6C. Alternatively, it is mechanically firmly fixed to the metal support portion 6D of the fixed contact support body 6 in an electrically insulated state with glass or the like. The right end of the support portion 6D is fixed to the cover plate 1 by a method such as spot welding. The support portion 6D and the tip portion 6B to which the fixed contact is fixed are electrically connected by a heating conductor 6F having a specific resistance, a cross-sectional area, and a length selected. That is, the left end 6F ₁ of the heating conductor 6F is connected to the tip 6B by a method such as spot welding, and the right end 6F ₂ is conductively connected to the support 6D by welding or the like. Especially when it is necessary to operate with a small current, the resistance value of the heating conductor must be increased, so that a metal coating or a carbon coating can be attached on the joint 6C. Since the fixed contact support 6 is composed of a ceramic joint 6C with a heat-resistant adhesive 6E for the tip 6B and the support 6D with sufficient mechanical strength, the strength of the heating conductor 6F itself is connected. It is sufficient that it does not separate from the part 6C or deform, and the resistance value can be selected in a wide range according to the magnitude of the abnormal current value flowing in the equipment to be protected by this thermal switch. Have.

The positions of the calibration piece 5B of the switch and the supporting portion 5A of the heat responsive plate 4 shown in FIGS. 1 and 2 show a state in which the operating temperature of the switch is calibrated to a predetermined value. The shape of the holder 5 showing the position of the calibration piece 5B before calibration is as shown in its plan view in FIG. 3, and the symbols in FIG. 3 are the same as those shown in FIG. If there is a reference, the calibration method will become clearer. In the counterclockwise direction, that is, in the direction indicated by arrow B, the calibration piece 5B is centered around the point indicated by arrow A of the calibration piece 5B.
It is provided with a perpendicular flange portion 5B ₁ to the paper surface in calibration piece 5B for deforming bending, the flange portion 5B ₁
It is easily conceivable to bend and deform by using a tool such as a screwdriver that inserts into the groove. It is preferable that the portion of the calibration piece 5B indicated by the arrow A has a cross section that is easily deformed.
When the tip of the calibration piece 5B is bent and deformed in the direction of the arrow B, it slides into the lower surface of the gentle mountain-shaped support portion 5D and the flange 5B ₁
The center part with a mark slides on the upper surface of the support part 5A
The supporting section 5A is bent by bending the easily deformable cross-section section 5A ₆
It is possible to increase the contact pressure between the movable contact 4A and the fixed contact 6A by pushing the heat responsive plate 4 fixed to the plate in the direction in which the left end is downward as shown in FIG. Thickness of the portion indicated with 5A ₆ is it is preferable to thin width any smaller than its neighboring Rino portion. FIG. 4 shows a cross-sectional view as seen in the direction of arrows IV-IV in FIG. 2, in which the positional relationship of each member of the holding body 5 is clearly shown. The symbols in FIG. 4 that are the same as those shown in FIGS. 1 and 2 are denoted by the same symbols, and the portions designated by 6G and 6H in the other symbols are the fixed contact support 6 It is a flange of the supporting portion 6D and is fixed to the cover plate 1 by welding or the like.

The container indicated by the symbol 7 is made by deep drawing an iron plate, for example, which has a closed end on the left side and an open end on the right side, as is apparent from FIGS. 1 and 2. The flange portion of the above is hermetically welded to the cover plate 1 by a method such as ring projection welding to form a hermetically sealed heat responsive switch.

〔The invention's effect〕

As described in detail above, the thermoresponsive switch of the present invention includes the calibration piece 5B.
Is inserted between the support portion 5D and the support portion 5A to which the heat responsive plate 4 is fixed, like a wedge, so that the inclination of the support portion 5A is slightly increased, but the deformation movement distance of the calibration piece 5B is increased. It is easy to precisely calibrate the inversion temperature of the reaction plate, and there is an excellent effect that almost no influence such as springback occurs.

[Brief description of drawings]

FIG. 1 is a partially cutaway plan view of an embodiment of a thermoresponsive switch of the present invention, and FIG. 2 is a longitudinal sectional view.
FIG. 3 is a plan view of the components used in the embodiment of FIG. 1, and FIG. 4 is a transverse sectional view taken along the line IV-IV of FIG. 4 ... Thermal response plate, 4A ... Movable contact, 5A ... Thermal response plate support part, 5B ... Calibration piece, 5C / 5E ... Beam member, 5D ... Bearing part, 6 ... Fixed contact support, 6A: Fixed contact.

Claims (1)

[Claims] 1. A fixed contact support is conductively fixed to either one of two metal members which are electrically insulated and held as terminals of a switch, and a fixed contact is fixed near the tip thereof, and the other metal member. Is formed by drawing a bimetal plate into a shallow dish so that it can move in reverse when the temperature changes, and the fixed end of the heat-responsive plate is electrically conductively fixed. It has two beam members that are almost parallel to each other so as to sandwich the part, one beam member is provided with a calibration piece, and the other beam member is provided with a support portion that receives the tip end portion of the calibration piece. The movable contact fixed near the free end of the heat responsive plate and the fixed contact are closed at room temperature, and the heat responsive plate suddenly reverses at a predetermined temperature to snap the movable contact from the fixed contact. Deform the calibration piece to separate it with By inserting the heat-responsive plate into a wedge shape between the support part of the heat-responsive plate and the support part that receives the tip of the calibration piece, the movable contact of the support part of the heat-responsive plate increases or decreases the contact pressure with respect to the fixed contact. A thermo-responsive switch characterized by a structure that can be precisely adjusted.