JPH0324730B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a temperature switch.

Conventionally, as shown in FIG. 8, this type of temperature switch has a fixed contact 16' fixed to an external terminal 6', and a movable contact spring 23' whose one end is fixed to a movable spring fixing base 9'. Movable contact 2 fixed at the end
6' is provided so as to be contactable, and an inverted bimetal 18' disposed below the movable contact spring 23' is provided so as to come into contact with the protrusion 11' on the movable spring fixing base 9' when inverted. . Therefore, when the ambient temperature reaches the set temperature, the inverted bimetal 18' is warped in the opposite direction as shown in FIG. When the movable contact spring 2
3' is pushed up, and the movable contact 2 is moved from the fixed contact 16'.
6' will be opened.

However, in the above configuration, the movable contact spring 2
When the inverted bimetal 18' is moved upward, the inverted bimetal 18' whose central portion abuts the protrusion 11' comes into contact with the movable contact spring 23' at both ends.
There was a risk of damage to the 8'.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a temperature switch which eliminates the above-mentioned drawbacks, prevents damage to the inverted bimetal, and improves reliability.

The temperature switch of the present invention will be explained below with reference to the drawings.

1 to 3 show embodiments of the present invention. In the figures, a box-shaped housing 1 is shown.
One end surface is open, and the switch body 3 is accommodated in grooves 2 formed on both side walls of the housing 1 at both side edges thereof. The base 4 of the switch body 3 is made by punching a flat metal plate by press working, bending and doweling to form a switch board base, and then molding it with synthetic resin, and then forming parts corresponding to external terminals. The part corresponding to the movable contact spring fixing plate is formed independently.

To be more specific, the base 4 has a longitudinal base 5 made of molded synthetic resin, and at one end of the base 5 there is a pair of main external terminals 6 extending in the length direction.
The inner end of the auxiliary external terminal 7 is buried therein, and most of the movable spring fixing plate 9, which extends in the length direction and has a stepped portion 8 at its free end, is buried in the other end. Also, approximately in the center of the platform 5 is a low protruding platform 1.
0 is bulged out, a small push-up projection 11 is erected upward, a wall 12 that can close the open end surface of the housing 1 is bulged upward at one end, and a cylindrical column is provided at the center of the other end. A support protrusion 13 is provided upright, and semi-cylindrical locking protrusions 14 are provided on the other end edge at equal distances from the support protrusion 13.
15 are erected. In addition, the main external terminal 6
A main fixed contact 16 and an auxiliary fixed contact 17 having different sizes are fixed to the inner end of the auxiliary external terminal 7 located inside the wall 12.

On the other hand, a main reversing bimetal 18 and an auxiliary reversing bimetal 19 each having a concave curved surface having different operating temperatures are mounted on the base 4. The main and auxiliary inversion bimetals 18 and 19 have an elliptical shape when viewed from above, and their bases are located between the support protrusion 13 and the locking protrusion 14 or 15. Projection 13 and locking projection 14
Alternatively, notches 20, 20 and 21, 21 that can be engaged with 15 are formed. Therefore, the notch 2 is formed in the support protrusion 13 and the locking protrusion 14 or 15.
When 0, 20 and 21, 21 are engaged,
The main and auxiliary inverted bimetals 18 and 19 are mounted on the base 4.
It extends toward the edge opposite to the edge where the locking protrusion 14 or 15 is located. That is, most of the main and auxiliary inverted bimetals 18 and 19 overlap each other vertically when viewed from above, and their tips intersect with each other and extend toward opposite edges of the base 4. Furthermore, a hole 22 is bored in the center of the auxiliary inversion bimetal 19 through which the small push-up projection 11 of the base 4 can be inserted.
This push-up small projection 11 separates the main and auxiliary inversion bimetals 18 and 19 from each other.

The proximal end of the movable contact spring 23 is preferably fixed to the stepped portion 8 of the movable spring fixing plate 9 via a dowel. The movable contact spring 23 is bifurcated to form a main contact spring part 24 and an auxiliary contact spring part 25.
A main movable contact 26 and an auxiliary movable contact 27, which are capable of contacting the main and auxiliary fixed contacts 16 and 17 of the main and auxiliary external terminals 6 and 7, respectively, and which are different in size from each other are fixedly provided at the free ends of the terminals. Further, a main tongue piece 28 and an auxiliary tongue piece 29 extending downward and having different lengths are cut and raised in the main and auxiliary contact spring parts 24 and 25, and a push-down projection 30 is provided on the fixed end side of the auxiliary contact spring part 25.
are provided, and the main and auxiliary tongue pieces 28, 29
Further, the push-down projection 30 is provided so as to be able to come into contact with the main and auxiliary reversing bimetals 18 and 19 inside the edges of the main and auxiliary reversing bimetals 18 and 19. Further, a blocking tongue piece 32 is extended from the side edge of the auxiliary contact spring portion 25, and rides on a downward movement blocking step portion 31 protruding from the base 4 during upward movement. In addition, the open end of the housing 1 housing the switch body 3 is filled with a sealing adhesive 33.

Further, the operation of the temperature switch according to the present invention will be explained. In the temperature switch of the present invention, the electrical circuit includes the main external terminal 6, the main fixed contact 16, the main movable contact 26, the main contact spring part 24, the auxiliary contact spring part 25, the auxiliary movable contact 27, the auxiliary fixed contact 17, and the auxiliary external terminal 7. It is formed. When the ambient temperature of the device equipped with the temperature switch reaches the normal first set temperature for reversing the main reversing bimetal 18, the main reversing bimetal 18 performs a reversing operation, and the center of the main reversing bimetal 18 hits the push-up small protrusion 11. Since the inner portions of both ends abut against the main tongue piece 28 and the push-down protrusion 30, the main contact spring portion 24 is pushed up. As a result, the main movable contact 26 of the main contact spring portion 24 is separated from the main fixed contact 16 attached to the main external terminal 6.
The contacts are brought into an open state, and this is repeated to open and close the contacts as appropriate. At this time, the auxiliary reversing bimetal 19 is not reversed, and the auxiliary fixed and movable contacts 17 and 27 continue to be closed, but the electrical circuit is interrupted.

On the other hand, when a device equipped with a temperature switch reaches an abnormal second set temperature that causes the auxiliary reversing bimetal 19 to reverse due to cracks in the main reversing bimetal 18 or welding of the main fixed and movable contacts 16, 26, etc., the auxiliary reversing bimetal 19 19 is reversed, the auxiliary contact spring part 25 is pushed up via the auxiliary tongue piece 29, and the auxiliary movable contact 27 of the auxiliary contact spring part 25 is separated from the auxiliary fixed contact 17 attached to the auxiliary external terminal 7. The contacts are closed.

Further, in this case, the main reversing bimetal 18 which is intermittently operated at the first set temperature comes into contact with the push-up small protrusion 11 at its center and the main tongue of the main contact spring section 24 on the inner side of its edge when reversing. The fourth contact piece 28 contacts the push-down protrusion 30 of the auxiliary contact spring portion 25.
Since it operates as shown in FIG. 5 from the position shown, the bending stress applied to the main reversal bimetal 18 is sufficiently reduced.

It should be noted that the above-described configuration is also applicable to a temperature switch having a single inverted bimetal shown as a conventional product in FIGS. 8 and 9.

FIG. 6 shows another embodiment of the present invention, in which a small push-up projection 28a is attached to the lower surface of the center of the contact spring portion 24a, and the base 4
A pair of push-up small protrusions 11a, 11a that can come into contact with the inside of the edge of the inverted bimetal 18a are provided on the upper surface of the inverted bimetal 18a. In this case as well, as shown in FIG. 7, force is applied to the center of the inverted bimetal 18a as well as to the inner side of both ends thereof during inversion, so that the bending stress is reduced.

FIG. 10 is an explanatory view of the operation, and shows the state of engagement between the reversing bimetal 18, its notch 20, and the locking protrusion 14, in which a is the abutting portion at the time of reversing, b is
indicates the center, and c indicates the other contact portion.

As mentioned above, according to the temperature switch of the present invention,
By providing notches on both sides of one end of the inverted bimetal, the bimetal is better supported, and by providing the contact area between the bimetal and the push-up protrusion approximately in the center of the bimetal, bending is prevented. The stress distribution is made symmetrical with respect to the push-up protrusion and is less likely to be biased to one side, so that the fatigue due to the repeated operation of the inverted bimetal is less likely to be biased to one side, thereby preventing damage to the inverted bimetal and increasing the length of the product. It is possible to extend the service life.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of one embodiment of the temperature switch of the present invention, FIG. 2 is an internal plan view, FIG. 3 is an internal side view, FIGS. 4 and 5 are operation explanatory views, and 7 is a simplified side view of another embodiment of the present invention, FIG. 7 is an explanatory diagram of the same operation, FIG. 8 is a simplified side view of a conventional temperature switch, FIG. 9 is an explanatory diagram of the same operation, and FIG. 10 is an explanatory diagram of the same operation. FIG. 3 is an explanatory diagram of the operation of the inverted bimetal of the invention. DESCRIPTION OF SYMBOLS 1... Housing, 2... Groove, 3 ... Switch body, 4... Base, 5... Base part, 6... Main external terminal, 7... Auxiliary external terminal, 8... Step part, 9... ...Movable spring fixing plate, 10...Protrusion base part, 11...Push-up small projection, 12...Wall part, 13...Support protrusion, 1
4, 15... Locking protrusion, 16... Main fixed contact, 1
7... Auxiliary fixed contact, 18... Main reversing bimetal, 19... Auxiliary reversing bimetal, 20, 21...
...Notch, 22...hole, 23...movable contact spring,
24...Main contact spring part, 25...Auxiliary contact spring part, 26...Main movable contact, 27...Auxiliary movable contact, 28...Main tongue piece, 29...Auxiliary tongue piece, 30...
...Pushing projection, 31...Downward movement blocking step, 32...Blocking tongue piece, 33...Adhesive.

Claims (1)

[Claims] 1. A movable terminal including a base, a plurality of external terminals held by the base and attached with fixed contacts, and a movable contact capable of contacting the fixed contacts, and having an approximately U-shaped main contact spring and an auxiliary contact spring. A contact spring, a movable spring fixing plate that is held on the base and holds the movable contact spring, and two main and auxiliary reversing bimetals that independently operate each of the movable contact springs, and two bimetals. In a temperature switch having a double protection function for one circuit, in which a bimetal is inserted in series with the electric circuit to be opened, supporting protrusions provided on the base are provided on both sides of one end of each bimetal. If this bimetal is reversed, the contact part with the push-up protrusion should be at approximately equal intervals with both notches, and closer to the center of the bimetal than the line connecting both notches. A temperature switch characterized by being provided with a temperature switch.