KR200357427Y1 - Thermostat - Google Patents

Abstract

An object of the present invention is to provide a thermostat that can improve the electrical performance by improving the junction structure between the movable contact and the contact arm to maximize the contact area between the contact arm and the movable contact even when riveting.

In the present invention, in the thermostat, embossing is formed on the contact arm where the movable contact is installed, and a rivet hole is formed in which the protrusion of the movable contact is inserted into the embossing, and a rivet head is formed on the protrusion of the movable contact. Formed to provide a thermostat of the structure for riveting the movable contact to the contact arm.

Description

Thermostat {THERMOSTAT}

The present invention relates to a thermostat, and more particularly, to a thermostat capable of improving the structure of a contact arm so as to increase electrical performance between the contact arm and a contact installed in the contact arm.

In general, a thermostat is an electrical component for controlling an open / close contact on and off by sensing a change in ambient temperature by a built-in thermostat.

Generally, a disk-shaped bimetal is used as the thermal member, and when the ambient temperature exceeds the first set temperature, the curved shape is displaced, and when the ambient temperature drops and falls below the second set temperature, the original member is returned. You will return to the state of.

Therefore, the thermostat converts the on / off state of the open / close contact by using the property of this heat-sensitive body.

The thermostat is usually installed between the fixed contact point and the movable contact installed on the circular base, the terminal connected to each of the contacts and extending outside the circular base, one terminal is installed between the movable contact and the movable contact elastically close to the fixed contact A contact arm, a top cover covering the upper portion of the circular base, a guide pin slidably fitted in the center hole of the top cover to be in close contact with the contact arm, and a disc-shaped bimetal for selectively pushing the guide pin on the top cover. And a cap overlying the bimetal and extending to the top cover and the circular base side to form an outer shape.

Accordingly, when the bimetal expands in the opposite direction in response to the temperature, the guide pin is pushed outward by the bimetal and pushes the contact arm. As the contact arm is pushed, the movable contact installed at the tip of the contact arm is separated from the fixed contact and connected to the terminal. To cut off the circuit.

In the thermostat of the structure described above, the movable contact is usually attached to the contact arm through rivets or spot welding, but in the case of the conventional structure, there is a problem that the electrical properties of the contact portion are not good and the cost is high.

That is, in the structure of riveting the movable contact to the contact arm, as shown in FIG. 4, the protrusion 121 of the movable contact 120 is inserted into the rivet hole 110 formed in the contact arm 100 and the protrusion 121 is formed. Pressing) to form the rivet head 122, the contact arm 100 is lifted during riveting when the gap 130 is generated between the movable contact 120 and the contact force between the contact arm and the movable contact falls do.

This is because the contact arm that provides elastic force to the movable contact is very thin. As the rivet hole expands to the outside due to the pressure generated at the rivet coupling part, the thin contact arm is lifted around the rivet hole. will be.

Therefore, there is a gap between the movable contact point and the contact arm, so that the contact area is not reduced significantly, and the contact force between the inner circumference of the rivet hole and the movable contact is remarkably increased as the gap between the inner circumference of the rivet hole of the contact arm and the projection of the movable contact increases over a long period of use. This results in a drop in the electrical properties between the movable contact and the contact arm.

In addition, when the movable contact is attached to the contact arm by spot welding, the cost required for spot welding is much higher than that of the rivet coupling method, resulting in high manufacturing cost of the thermostat itself and inferior economic efficiency.

Therefore, the present invention has been devised to solve the above problems, and improves the junction structure between the movable contact and the contact arm, thereby maximizing the contact area between the contact arm and the movable contact even when riveting, thereby improving electrical performance. The purpose is to provide a thermostat.

1 is an exploded perspective view of a thermostat according to an embodiment of the present invention,

Figure 2 is a perspective view showing a contact structure in the thermostat according to an embodiment of the present invention,

Figure 3 is a side cross-sectional view showing a contact connection structure of the thermostat according to an embodiment of the present invention,

Figure 4 is a side cross-sectional view showing a contact connection structure of the thermostat according to the prior art.

Explanation of symbols on the main parts of the drawings

10: thermostat 13: movable contact

21: projection 22: rivet head

30 contact arm 31 embossing

32: rivet hole

In order to achieve the object as described above, the subject innovation is that the circumference of the rivet hole of the contact arm provided with the movable contact is bent and protruded.

To this end, the present invention has a structure in which the embossing is convexly formed on the contact arm in which the movable contact is installed, and a rivet hole is formed in which the protrusion of the movable contact is inserted into the embossing.

Here, the embossing is preferably protruded in the direction opposite to the contact surface of the movable contact.

Accordingly, the external pressure applied to the rivet hole at the time of the riveting tightening acts as a rotation moment of the embossed portion, so that the contact arm can be brought into close contact with the movable contact.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail.

1 is an exploded perspective view of a thermostat according to an embodiment of the present invention, Figure 2 is a perspective view showing a contact structure in the thermostat according to an embodiment of the present invention, Figure 3 is a thermostat according to an embodiment of the present invention Side cross-sectional view showing a contact connection structure of a.

According to the drawings, the thermostat 10 has a circular base 11 constituting the body, the fixed contact 12 and the movable contact 13 provided in the circular base 11, the circular base 11 Two terminals 14 and 15 installed in the inner space and electrically connected to the contacts 12 and 13, respectively, and extending outward from the circular base 11, and fixing the two terminals to the circular base 11. A fixed rivet 23, a cover base 16 covering the lower portion of the circular base, and is installed between the one terminal 15 and the movable contact 13, the movable contact 13 is elastic to the fixed contact 12 A contact arm 30 to be in close contact with each other, a guide pin 17 which is slidably installed in the center of the circular base 11, and is in close contact with the contact arm 30, and is placed at one end of the circular base to guide the guide pin. Disc-shaped bimetal 18 for selectively pushing, said bimetal (18) a cap 19 overlying and installed in the circular base, a resistor 20 installed in the circular base and located proximate to the bimetal.

According to the thermostat 10 of the present invention configured as described above, when the bimetal 18 senses the temperature by the heat generated by the resistor 20 and has a temperature higher than the temperature stored in the bimetal 18, it has a slight gradient. The disk-shaped bimetal 18 is reversed (expanded) and the reverse force acts on the guide pin 17 which is in contact with it, and pushes the contact arm 30 which is in contact with the lower part of the guide pin 17 to move downward. do. According to this movement, the movable contact 13 provided at the end of this contact arm 30 is turned OFF in the ON state which is in contact with the fixed contact 12, thereby turning off the circuit of the apparatus. When the heat generated by the resistor 20 and the temperature around the cap 19 are lowered by the bimetal 18 storage temperature, the bimetal 18 is inverted again to energize the contacts 12 and 13. .

Here, the movable contact 13 has a structure in which a circular protrusion 21 protrudes in the center of the rear side for rivet coupling, and the contact arm 30 has one end attached to the terminal 15 and a fixed contact ( 12) The other end extending to the position has a structure in which a rivet hole 32 into which the projection 21 of the movable contact 13 is fitted is formed.

Therefore, the movable contact 13 is riveted to the tip of the contact arm 30 having a very thin thickness, the contact arm 30 to maximize the contact area when riveting the movable contact 13 The coupling part has a structure protruding to one side.

That is, the contact arm 30 has a circular embossing 31 protruding in a direction opposite to the joining surface of the movable contact 13 at the tip, and the movable contact 13 on the embossing 31 forming surface. It is a structure in which a rivet hole 32 into which the projection 21 is inserted is formed.

This structure secures rigidity to the thin contact arm 30 and generates elastic force at the embossing 31 so that the inner circumferential surface of the rivet hole 32 is protruded 21 of the movable contact 13 even when used for a long time. It allows you to maintain elastic contact with the sides.

In addition, the above-described structure generates a height difference between the position of the inner circumferential surface of the rivet hole 32 and the position of the contact of the contact arm 30 substantially in contact with the movable contact 13.

Accordingly, when the rivet head 22 is formed on the protrusion 21 of the movable contact 13 through riveting, the expansion force of the protrusion 21 and the pressing force of the rivet head 22 are substantially the movable contact 13. Rather than being applied to the contact surface of the contact arm 30 in contact, it is applied to the rivet hole 32 at a position spaced apart from the actual joint surface by the embossing 31, so that the contact arm is driven by an external force applied to the rivet hole 32. The contact surface of 30 may be in close contact with the movable contact 13.

The above mentioned contents can be more clearly understood through FIG. 3.

In Figure 3 it can be seen that the embossing 31 is formed in a gentle slope at the tip of the contact arm 30, the rivet hole 32 is formed on the upper end of the embossing 31, the movable contact 13 is The protrusion 21 on the rear surface of the movable contact 13 is inserted through the rivet hole 32 and is fastened to the rivet hole 32 by forming a rivet head 22 at the tip of the protrusion 21 through riveting.

As such, when the protrusion 21 is riveted to the rivet hole 32, the protrusion 21 is expanded outward by the pressing force generated when the rivet head 22 is formed, and the inner circumferential surface of the rivet hole 32 is fixed to a predetermined pressure P. Pressurized.

In this case, the rivet hole 32 is substantially spaced apart from the contact surface 33 in which the movable contact 13 is in contact with the contact arm 30 by a predetermined distance L, and thus the inner circumferential surface of the rivet hole 32 as described above. When the pressure of P is applied to the outside, a rotation moment is generated at the point of contact between the contact arm 30 and the movable contact 13, that is, at the point A at which the embossing 31 is formed, and thus the contact surface of the contact arm 30 ( 33) is to be in close contact with the movable contact (13).

That is, when pressure P is applied to the inner circumferential surface of the rivet hole 32 spaced apart from the contact surface 33, the contact surface 33 of the contact arm 30 around the point A generates a rotational force corresponding to P × L. 3) the upper contact arm 30 has a property that the contact surface 33 is to rotate in a counterclockwise direction based on the A point.

Accordingly, the contact surface 33 of the contact arm 30 may be in close contact with the movable contact 13 through riveting.

On the other hand, Table 1 below is an experimental data comparing the electrical characteristics between the structure of the embossed contact arm by riveting the movable contact and the contact arm structure of the conventional embossing is not formed according to this embodiment.

TABLE 1

DCR (mm ohm) Movable Contact Temperature (℃) Contact arm according to the prior art 0.5 (min) 95 (min) Contact Arm with Embossing 2.5 (max) 85 (max)

In this case, DCR (DC resistance) is a resistance component generated by the contact of a metal, that is, an element that hinders the flow of current, and the lower the value, the better the characteristics.

In the above experiment, the temperature of the movable contact point was measured at the rivet head 22 portion of the movable contact riveted to the contact arm, and the highest state was maintained for 2 hours at room temperature by flowing an AC 25A overcurrent between terminals provided with each contact point. The temperature was measured.

In addition, the average value of each of five was derived in consideration of the fact that the result may vary depending on the rivet binding state.

Experimental results As shown in Table 1, in the case of the contact arm embossed according to the present embodiment, the DCR was 2.5 and the value was significantly lower compared to the DCR value of the conventional contact arm having no embossing structure. It can be seen that the characteristic is improved.

In addition, the experimental results confirm that the temperature of the movable contact is also lowered by more than 10 ℃. Considering that the higher the temperature of the contact is, the shorter the life of the contact is, according to the present embodiment, the embossed contact arm can further obtain the effect of extending the life of the contact.

According to the thermostat according to the present invention as described above, it is possible to increase the contact area between the contact arm and the movable contact to maximize the electrical performance.

In addition, it is possible to rivet the contact arm and the movable contact while increasing the electrical performance, thereby obtaining a cost reduction effect due to the rivet coupling, it is possible to secure the price stability through cost improvement.

In addition, it is possible to increase the quality of the product by extending the life of the contact.

Claims (3)

A circular base constituting the body, a fixed contact and a movable contact provided in the circular base, a terminal electrically connected to the contact and extending outward of the circular base, and connected between the one side terminal and the movable contact to provide a movable contact. A contact arm for elastically close contact with the fixed contact, a guide pin slidably installed in the center of the circular base to be in close contact with the contact arm, and a disc-shaped bimetal for selectively pushing the guide pin to be placed at one end of the circular base And a cap installed on the circular base to cover the bimetal, and a resistor installed in the circular base and positioned adjacent to the bimetal. Embossing is formed at the end of the contact arm, and a rivet hole is formed in which the protrusion of the movable contact is inserted into the embossing, and a rivet head is formed at the protrusion of the movable contact penetrated through the rivet hole to form the movable contact. Thermostat of riveting structure to contact arm. The thermostat of claim 1, wherein the embossing protrudes in a direction opposite to a contact surface of the contact arm and the movable contact. The thermostat of claim 2, wherein the embossing is circular in shape.