JPH0834076B2 - Contact opening / closing mechanism using bimetal plate - Google Patents

Description

The present invention relates to a contact opening / closing mechanism using a bimetal.

[Prior Art] Usually, when a circuit breaker or the like is constructed using a bimetal plate, one end of the bimetal plate is attached to a bimetal side terminal and a movable contact is attached to the other end. The movable contact is brought into contact with a fixed contact side terminal provided with a fixed contact to be contacted so as to be in contact with the fixed contact side terminal, and an electric current is applied between both terminals. The contact between the contacts is opened by utilizing the curvature of the bimetal plate caused by self-heating at this time.

Further, in order to open and close the contacts rapidly, a dogle mechanism by a spring is provided, or the bimetal plate itself is processed so as to perform a snap operation (for example, JP-A-52-17677). reference).

[Problems to be Solved by the Invention] In the structure of the conventional contact opening / closing mechanism as described above, in order to cause the bimetal plate to perform the reversing operation in the most preferable state, that is, the chattering phenomenon does not occur in the breaking and restoring operations. Therefore, it is necessary to adjust the fixed contact side terminal or the bimetal side terminal to the optimum related position. Therefore, it is not suitable for mass production.

Therefore, an object of the present invention is to provide a contact opening / closing mechanism that uses a bimetal plate capable of reliably preventing the chattering phenomenon, and thus to provide a contact opening / closing mechanism that facilitates mass production with less adjustment during manufacturing. To provide.

[Means for Solving the Problems] According to the present invention, a bimetal side terminal, a fixed end side portion joined to the bimetal side terminal, a folded portion continuous with the fixed end side portion, and the folded portion A substantially U-shaped bimetal plate having a free end side portion provided continuously with a movable contact, and a fixed contact side terminal provided with a fixed contact that comes into contact with the movable contact. , The movable contact is arranged so as to be in pressure contact with the fixed contact when not energized, and when the energization is performed, the folded-back portion is displaced in a direction in which the contact pressure between the two contacts is increased due to a bending operation due to self-heating, and the free contact The end side portion is configured to perform a snap operation according to temperature change to open and close the both contacts, and further, the junction point of the fixed end side portion with respect to the bimetal side terminal is the folding contact rather than the movable contact. It is possible to obtain a contact opening / closing mechanism using a bimetal plate, which is characterized in that it is located near the return portion.

[Operation] In the contact opening / closing mechanism using the bimetal plate of the present invention, the movable contact is in contact with the fixed contact when not energized, and the bimetal plate bends due to self-heating when energized. This bending moves the position of the folded portion of the bimetal plate. On the other hand, the free end side portion of the bimetal plate is configured to perform the snap operation due to the temperature change, that is, the free end side portion is like a rigid body except when the snap operation is performed, and the bimetal plate is Since the joining point of the fixed end side to the side terminal is located closer to the folding part than the movable contact, when the bimetal plate is energized and the folding part is displaced, the free end side joins as if the folding part were the force point. It acts like a lever with the point as the fulcrum and the movable contact as the point of action, and strongly presses the movable contact against the fixed contact. When the stress in the free end side portion caused by the bending of the bimetal plate exceeds a predetermined value, the free end side portion performs a snap operation,
The bimetal plate operates in reverse. As a result, the movable contact is instantly separated from the fixed contact. As described above, the closer the movable contact is separated from the fixed contact, the more the movable contact is pressed against the fixed contact, so that the chattering phenomenon is reliably prevented.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a top view of the contact opening / closing mechanism of the present invention, and FIG. 2 is a side view thereof.

The bimetal-side terminal 1 serving as one terminal to which an electric current is supplied is horizontally fixed and supported by a terminal support 2 made of an insulating material such as a mold. The terminal 1 is bent downward at a portion 3 located at the center of the support body 2 and then folded again so as to be horizontal. The terminal 1 is bent upward again at a portion 4 away from the support 2, and then extended obliquely upward to form a bimetal joint 5.

The bimetal plate 6 includes a fixed end side portion 6a joined to the bimetal side terminal 1, a folded back portion 6b continuous with the fixed end side portion 6a, and a movable contact 13 connected to the folded back portion 6b and described later. It has a free end side portion 6c provided. The bimetal plate 6 has a fixed end side portion 6a joined to the terminal 1 at the bimetal joint portion 5 of the terminal 1 and folded back at the folded portion 6b, so that the whole is formed in a substantially U shape. The bimetal plate 6 is formed so as to be substantially symmetrical with respect to a center line 8 which is substantially parallel to the terminal 1. A slit 6d is provided in a portion of the bimetal plate 6 above the center line 8 in the drawing, that is, in a free end side portion 6c substantially parallel to the center line 8. And
The free end side portion 6 is configured to perform a snap operation by pressing both side portions 6e and 6f of the slit 6d. This kind of processing is described in Japanese Utility Model Publication No. 37-16631 or Japanese Patent Application No. 37-15066, which the applicant of the present invention has applied for separately. A movable contact 13 is fixed to the lower surface of a free end 6g of the free end side portion 6c opposite to the folded-back portion 6b.
As is apparent from FIG. 1, the junction point (point indicated by reference numeral 5) of the fixed end side portion 6a with respect to the bimetal side terminal 1 is located closer to the folded portion 6b than the movable contact 13. As is well known, the bimetal plate 6 has upper and lower surfaces formed of materials having different temperature coefficients. In the present embodiment, the second
As shown in the figure, the lower surface 14 side is formed of a high expansion material and the upper surface 15 side is formed of a low expansion material.

The fixed contact 16 that is opposed to and contacts the movable contact 13 provided on the bimetal plate 6 has an end portion 18 of the fixed contact side terminal 17 that is arranged substantially parallel to the bimetal side terminal 1 and substantially symmetrical with respect to the center line 8. Is stuck to. Terminal 17 is terminal 1
Similarly, is supported by the support body 2, is bent downward at the central portion of the support body 2 and is bent again in the horizontal direction, and the fixed contact 16 is fixed to the tip portion.

Next, the operation will be described. In the non-energized state, the movable contact 13 of the bimetal plate 6 contacts the fixed contact 16 of the terminal 17 at a predetermined pressure as shown by the solid line in FIG. The positional relationship is set. When a necessary current is supplied between the terminal 1 and the terminal 17 in this state, the current flows from the terminal 1 to the bimetal plate 6 via the joint portion 5 and then to the terminal 17 via the movable contact 13 and the fixed contact 16. Due to this energization, the bimetal plate 6 self-heats, and the lower surface high expansion side 14 expands more than the upper surface low expansion side 15 due to the temperature rise at this time. Due to this expansion, the folded-back portion 6b of the bimetal plate 6 receives a force directed upward as indicated by an arrow 19 in FIG. 2, whereby the bimetal plate 6 is displaced upward by a distance 1 indicated by 20. That is, at this time, the bimetal plate 6 performs a cantilever operation with the joint portion 5 as a fixed end. Due to the upward displacement of the folded-back portion 6, the free end of the bimetal plate 6
6 g receives a reaction force downward as indicated by an arrow 21 with the joint portion 5 as a fulcrum.

Side of free end where slit 6d of bimetal plate 6 is formed
Also in 6c, internal force is generated to cause the lower surface to expand more than the upper surface and bend due to self-heating, but due to the existence of external force that was applied in advance due to the snap operation, the shape shown by the solid line in Fig. 2 is maintained for the first time. ing. That is, the fixed end side of the bimetal plate 6
6a is displaced in proportion to the temperature rise, but the free end side 6c
Has a higher rigidity than the fixed end side part 6a because it is pressed around the slit 6d, so until the reversing operation,
Since it keeps its shape, by the displacement of l shown by 20,
The reaction force indicated by 21 is obtained. However, when the temperature due to self-heating further rises, a reversing operation occurs due to the snap operation at the moment when the bending force of the bimetal plate 6 exceeds the external force.
By this snap operation, the bimetal plate 6 moves to the position shown by the chain double-dashed line in FIG. 2, and the movable contact 13 is instantly separated from the fixed contact 16.

In the above embodiment, the bimetal plate 6 is formed by joining the bimetal plates having different characteristics at the upper part and the lower part of the center line 8 by welding or the like, so that the contact opening / closing operation having various characteristics can be performed. be able to.

As described above, according to the contact opening / closing mechanism of the present invention,
Since the movable contact and the fixed contact receive a stronger contact pressure immediately before opening, chattering operation immediately before opening can be reliably prevented, and stable opening and closing can be performed.

As a result, the contact opening / closing mechanism of the present invention does not require adjustment work of the contact position or the like for stable operation at the time of manufacture, and is therefore suitable for mass production.

Further, the contact opening / closing mechanism of the present invention can be applied to either an automatic reset type or a manual reset type.

[Brief description of drawings]

FIG. 1 is a top view showing the configuration of a contact opening / closing mechanism of the present invention, and FIG. 2 is a side view thereof. 1: Terminal plate on the bimetal side, 2: Support, 5: Joined part, 6: Bimetal plate, 7: Folded end, 9: Slit, 12: Free end, 13:
Movable contact, 16: Fixed contact, 17: Fixed contact side terminal board.

Continuation of the front page (56) References JP-A-49-121182 (JP, A) JP-A-52-17677 (JP, A) JP-A-58-117625 (JP, A) Actual development 57-132345 (JP , U) Actual Development Sho 59-46440 (JP, U) Japanese Patent Sho 37-15066 (JP, B1) Actual Public Sho 37-16631 (JP, Y1) Actual Public Sho 49-6292 (JP, Y1) Registered Utility Model 366267 (JP, Z2)

Claims (1)

[Claims] 1. A bimetal side terminal, a fixed end side portion joined to the bimetal side terminal, a turnback portion continuously provided to the fixed end side portion, and a movable contact provided continuously to the turnback portion. And a fixed contact side terminal provided with a fixed contact that comes into contact with the movable contact. The bimetal plate has the movable contact fixed when the power is not supplied. It is arranged so as to come into pressure contact with the contacts, and when energized, the folded-back portion is displaced in a direction in which the contact pressure between the contacts is increased due to a bending operation due to self-heating, and the free end side portion performs a snap operation due to a temperature change. The contact point of the fixed end side portion with respect to the bimetal side terminal is located closer to the folding portion than the movable contact is. Contact switching mechanism using a bi-metallic strip to symptoms.