JPH0222921Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a thermal relay, and particularly to a thermal relay that displaces a bimetal due to heat generated by a heater and opens the main circuit when an abnormal current flows in the main circuit of a motor or the like.

Generally, electric motors and the like are provided with various safety devices to protect them from abnormal currents caused by failures or unexpected accidents.

Thermal relays are a type of safety device that detects the amount of heat generated by the heater when excessive current flows in the main circuit of a motor, etc., and opens the contacts when the amount of heat generated exceeds a certain value. It is formed to cut off the coil circuit of the electromagnetic contactor connected to the contact circuit and disconnect the main circuit.

Conventional thermal relays include a bimetal that is installed near a heater connected to the main circuit, and is displaced by heat generated by the heater during overcurrent, and when the displacement of the bimetal reaches a predetermined amount, it crosses the dead center and reverses, opening the circuit. It is formed of a contact mechanism and a transmission means that transmits the displacement of the bimetal to the contact mechanism.When the heater generates heat due to abnormal current, etc., the bimetal bends and displaces in response to the amount of heat generated, and this displacement The amount is transmitted to the contact mechanism by a transmission means, such as a lever mechanism that moves in response to the displacement of the bimetal. When the amount of displacement of the bimetal reaches a predetermined amount, the contact mechanism is activated, the movable contact is separated from the fixed contact, and the circuit is opened.

However, the contact mechanisms in conventional devices of this type only have contacts for opening and closing the main circuit. There were inconveniences such as the need to provide a separate contact switching device for opening and closing.

The present invention was devised in view of the above-mentioned conventional problems, and its purpose is to provide a simple summer relay with a structure that has separate opening/closing mechanisms for both the first circuit and the auxiliary circuit. be.

The present invention consists of a bimetal that is installed near the heater connected to the main circuit, and is displaced by heat generated by the heater during overcurrent, and when the displacement of the bimetal reaches a predetermined amount, it is reversed beyond the dead center and opens the circuit. A thermal relay including a contact mechanism and a transmission means for transmitting the displacement of the bimetal to the contact mechanism, wherein the contact mechanism is made of an insulating material, is supported on a contact mechanism board so as to be swingable in a seesaw manner, and is biased by a biasing spring. an operator having stable positions at both swing end positions beyond the point, a fixed contact disposed on the contact mechanism board, and a movable contact adhesively fixed to one end of the operator; a first contact portion that engages with the operator to open and close a first circuit; a second contact portion that engages with the other end of the operator to open and close an auxiliary circuit different from the first circuit; is provided, and when the amount of displacement of the bimetal exceeds a predetermined amount due to the heat generated by the heater, the operator is reversed beyond the dead center,
It is characterized in that both contact parts operate together.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows an embodiment of a thermal relay according to the present invention, in which a heater 10 is connected to the main circuit of an electric motor (not shown), and a bimetal 12 is connected to the base of the heater 10 in the vicinity of the heater 10. The heater 10 is fixed to the heater 10, and is formed to curve and deform using the base as a fulcrum in response to the amount of heat generated by the heater 10. An interlocking plate 14 is provided at the tip of the bimetal 12.
is installed horizontally, and the bimetallic 12
The amount of displacement appears as the amount of movement of the interlocking plate 14 in the AB direction.

On the other hand, an adjuster 16 is supported on a contact mechanism board or a main body base (not shown), and a lever mounting piece 18 is suspended from the lower end of the adjuster 16. A lever 20 is attached to the lever mounting piece 18 facing downward, and the tip of the lever 20 is in contact with the tip of the interlocking plate 14 described above. Further, an operating piece 22 extends horizontally from the tip of the lever mounting piece 18, and the amount of displacement of the bimetal 12 is transmitted from the interlocking plate 14 to the operating piece 22 via the lever 20. This operation piece 22 is provided to transmit the amount of displacement of the bimetal 12 to the contact mechanism, that is, to press a biasing spring (described later) and reverse the operation element (described later).

An adjustment screw 24 is in contact with the upper end of the adjuster 18, and by tightening or loosening the adjustment screw 24, the adjuster 16 is rotated about the support portion, and the lever 20 and the interlocking plate 14 are rotated. It is possible to adjust the contact position of the
It is possible to change the setting of the reversal position of the operator with respect to the amount of displacement of the bimetal 12 as appropriate.

Next, the contact mechanism in this embodiment will be explained.

In FIG. 1, a first fixed contact 26 and a second fixed contact 28 are respectively arranged on a contact mechanism board (not shown).

On the other hand, an operator 30 made of an insulator is supported on the contact mechanism board so as to be able to freely swing on a seesaw, and in this embodiment, a support plate 30 attached to the contact mechanism board
2, it is supported in a seesaw manner. A first movable contact 34 is attached and fixed to the upper end of the operator 30, and the first movable contact 34 and the above-described first fixed contact 26 form a first contact part, which opens and closes the first circuit. will be held. A thin metal piece 36 extends to the movable contact 34 to a position where the support plate 32 and the operator 30 are supported.
6, and an electric path leading to an external circuit via the support plate 32.

A second movable contact 38 is arranged opposite the second fixed contact described above. The upper end of the second movable contact 38 is engaged with the lower end of the operator 30 described above. A second contact portion is formed by the second fixed contact and the second movable contact, and opens and closes an auxiliary circuit such as an operation display or an alarm.

The opening/closing operation of the first contact portion and the second contact portion is performed by the later-described reversal swinging operation of the operator 30, and in order to stably hold both the reverse swing end positions, a biasing spring 40 is used. provided.

The biasing spring 40 has one end fixed to a screw 42 screwed into the support plate 32, and the other end engaged with the upper part of the operating element 30 so as to constantly urge the operating element 30 downward. There is.

The reversal behavior of the operator 30 in this embodiment will be described below.

FIG. 1 shows a state in which the first contact portion is closed;
In other words, a state is shown in which the first circuit is closed, and in this state, when an abnormal current flows through the main circuit and the heater 10 is overheated, the bimetal 1
The amount of bending displacement of 2 is transmitted as the amount of displacement of the operation piece 22, and the biasing spring 40 is pressed by the operation piece 22. As a result, the operator 30 rotates in the C direction and is reversed instantaneously after passing the dead center, and as shown in FIG. 2, the first contact part is opened, that is, the first circuit is opened, and the second contact part section is closed, that is, an auxiliary circuit such as an alarm is closed.

In order to return the operator 30 to its original position, a reset lever 44 is provided in this embodiment, and by pushing the reset lever 44 downward, the operator 30 is rotated in the direction D in FIG. Ru. Then, the moment the operator passes the dead center, the operator 30 is reversed again and returned to its original position.

The characteristic feature of this embodiment is that the contact part is formed of a first contact part and a second contact part, and the opening/closing mechanism of both contact parts is constructed by a simple operation element reversing mechanism. This is what is being done.

As a result, it is possible to design the operating voltage of the first circuit and the operating voltage of the auxiliary circuit to be different voltages, which is very convenient to use, and because the mechanism is simple, it is possible to reduce manufacturing costs. be.

As explained above, according to the present invention, the first and second
Since both contact parts are provided, the first circuit and the auxiliary circuit can be opened and closed with the same device, and the contact opening/closing device for the auxiliary circuit required in conventional devices is not required, making it very convenient to use and economically advantageous. It is possible to make a significant contribution to

[Brief explanation of the drawing]

FIG. 1 is a structural explanatory diagram of a thermal relay according to the present invention, and FIG. 2 is a structural explanatory diagram showing an inverted state of the thermal relay according to the present invention. In each figure, the same members are given the same symbols, 10 is a heater, 12 is a bimetal, 26 is a first fixed contact,
30 is an operator, 34 is a first movable contact, 40 is a biasing spring, and 44 is a reset lever.

Claims (1)

[Claims for Utility Model Registration] (1) A bimetal that is installed near the heater connected to the main circuit and is displaced by heat generated by the heater during overcurrent, and when the displacement of the bimetal reaches a predetermined amount, it crosses the dead center. A thermal relay includes a contact mechanism that is reversed to open a circuit, and a transmission means that transmits the displacement of the bimetal to the contact mechanism, wherein the contact mechanism is made of an insulator and is able to see-saw freely on the contact mechanism board. an operating element supported by a biasing spring and having stable positions at both swing end positions beyond the dead center, a fixed contact disposed on the contact mechanism board, and a movable contact adhesively fixed to one end of the operating element. a first contact portion that engages with one end of the operator to open/close a first circuit; and a first contact portion that engages with the other end of the operator to open/close an auxiliary circuit different from the first circuit. A second contact portion is provided, and when the amount of displacement of the bimetal exceeds a predetermined amount due to the heat generated by the heater, the operator is reversed beyond the dead center and both contact portions are activated. Thermal relay. (2) In the thermal relay described in claim (1) of the utility model registration, a reset lever is provided that engages with the operator in the reversed state, and the operation of the reset lever causes the operator to be reversed again. A thermal relay that is characterized by returning to its original position.