JPH01302628A - Switch device - Google Patents

Abstract

PURPOSE:To prevent chattering and improve reliability by fixing a movable member provided with a movable contact and a deformation member to each other at the separate position from the movable contact and constituting the end section of the deformation member in a free end so that the movable member is displaced and the movable contact is moved as the deformation member is deformed. CONSTITUTION:A bimetal plate 7 is bent downward, the end section opposite to its fixed side is formed in a free end. A movable contact 4 is provided on the end section side opposite to the fixed side of a movable contact support plate 3, the movable contact 4 is pressed to a fixed contact 9 by the elasticity of the movable contact support plate 3 in the ordinary state, the movable contact support plate 3 and a conducting plate 8 are electrically connected, a switch device is in the on state. One end side of the bimetal plate 7 is stuck and fixed to the movable contact support plate 3, thus the bimetal plate 7 with the curvature corresponding to the set temperature may be selected. Assembling is simplified, the occurrence of chattering and contact deposition caused by the error in the distance alignment is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a switch device, and particularly to a switch device that opens and closes in response to temperature changes.

BACKGROUND OF THE INVENTION Electrical machines such as conventional motors generate heat when they are in an abnormal state, and if they are continued to be used unchecked, the insulation coating of the windings burns, making them unusable. In order to prevent this, a switch device (protection device) is used that uses a bimetal and opens a contact in response to abnormal current and abnormal temperature to turn the device into an OFF state.

Some of the above-mentioned switch devices have structures shown in FIGS. 7 to 10.

FIG. 7 is an internal plan view of the switch device 21, and FIG.
FIG. 9 is an enlarged partial sectional view of FIG. 8.

An insulating plate 3 is placed on the bottom of the housing part 22 made of cold-rolled steel.
A first conductive plate 25 is provided via the 0A, and a second conductive plate 28 is provided on the first conductive plate 25 via an insulating plate 30.
is provided. A movable contact support plate 23 is fixed to the end of the first conductive plate 25 by welding, and a movable contact 24 is attached to the tip of the movable contact support plate 23. The bimetal plate 2 is attached to the first conductive plate 25 by a fixture 31.
7 is fixed. The movable contact support plate 23 has its through hole 23
b fits into the fixture 31 without contact, and the movable contact 24
is in contact with a fixed contact 29 provided on the second conductive plate 28. In this state, the two protrusions 23a, 23a of the movable contact support plate 23 are separated from the bimetal plate 27 by a distance of d1 (not shown in FIG. 9), and the elasticity of the movable contact support plate 23 allows the movable contact is in pressure contact with the fixed contact 29, the first and second conductive plates 25, 28 are electrically connected, and the switch device 21 is in the ON state. The terminal portion 25a of the first conductive plate 25 is connected to the lead wire 33, and the terminal portion of the second conductive plate 28 is connected to the lead wire 32. Terminal parts 25a, 28
A is a crimp terminal, but the crimp state is not shown.

The switch device 21 is installed in an electrical device (for example, a motor), not shown, and is connected in series between the electrical device and a power source.

If the temperature of the electrical equipment increases due to some trouble during use, and the temperature of the switch device 21 rises accordingly, or if a large current flows and the moving contact support plate 23 is heated, the bimetal plate 27 also rises in temperature and deforms to contact the protrusions 23a, 23a of the movable contact support plate 23, and the bimetal plate 23
As the deformation progresses further, the bimetal plate 27 pushes up the movable contact support plate 23 and the movable contact 24
is separated from the fixed contact 29, and the first and second conductive plates 25.2
8 is electrically cut off and the switch device 21 is turned off to protect the electrical equipment.

On the contrary, when the state shown in FIG. 10 is reached, the movable contact support plate 2
3 and the bimetal plate 27 dissipate heat and the temperature drops by 1.2, the bimetal plate 27 returns to its original shape and recedes from the protrusions 23a, 23a of the oJ contact support plate 23, and the switch device is in the state shown in FIG. It returns to the ON state again. If the time from the OFF state to the ON state of the switch device 21 is too short as described above, the switch device 21 will be turned ON,
This is inconvenient because the OFF cycle is repeated in a short period.

Therefore, the distance d between the bimetal plate 27 and the protrusions 23a, 23a of the movable contact support plate 23 is adjusted depending on the degree of curvature of the bimetal plate 27, and the temperature at which the OFF state is achieved (for example, in the range of 70-150"C). The vertical position of the bimetal plate 27 is adjusted by a fine adjustment means (not shown) installed in the fixture 31 so that the bimetal plate 27 has a predetermined dimension corresponding to a predetermined temperature inside the plate. I'm trying to do it. For example, the above OF
When the temperature of F is 70°C, d is 1 cylinder, ion 'c
Now let d be 21Tlln. However, this fine adjustment must be done manually for each item, which is troublesome and difficult to ensure accuracy.

If the interval d is too large, the device 21 will be turned off after the electrical appliance has been in an abnormal state for a long time, making it uncertain whether the electrical equipment will be protected. In addition, the distance d is too small.
■ becomes smaller, for example, it turns on and off at a cycle of 0.3 seconds.
F is repeated (6) called chattering, and finally the bimetal plate 27 and the movable contact support plate 23 become fatigued and cannot be deformed normally and the ON state continues, or the contacts are welded by sparks. occurs and the ON state continues, making it impossible to protect electrical equipment.

C.3 Purpose of the invention The present invention has been made in view of the above circumstances, and includes:
There is no need for precise position adjustment of deformable members (such as high-metal) that deform according to temperature changes, and there is no chattering, and there is no risk of loss of switch function due to fatigue of liquid distributing members or contact welding. The purpose is to provide a switch device with excellent reliability without any problems.

21. Structure of the Invention The present invention provides a switch device in which a movable contact is moved by deformation of a deformable member that deforms in response to temperature changes, and a switch is switched between this movable contact and a fixed contact corresponding to this movable contact. In this modification, the movable member provided with the movable contact and the deformable member are fixed to each other at a position different from the iiJ movable contact, and the tongue end of the front liquid distributing portion I4 is configured as a free end, and this deformation The present invention relates to a switch device characterized in that the movable member is displaced as the member is deformed, and the movable contact is moved 1111 times.

E, Example The present invention will now be described in detail.

1 and 2 show a switch device, FIG. 1 is an internal plan view of the switch device 1, and FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1.

An insulating plate 10 is placed on the bottom of the housing part 2 made of cold-rolled steel plate.
The conductive plate 8 is fixed via A by a fixture 15.15. A fixed contact 9 is provided at one end of the conductive plate 8, and a terminal 8a is provided at the other end. Conductive plate 8
A resin stand 14 is located above, and on the stand 14, from the bottom, near the end of the bimetal plate 7 and the end of the movable contact support plate (movable member provided with a movable contact) 3 are overlapped, and further A brass plate 6 is placed thereon, and these are fixed to a resin base 14 with fixtures 11. Due to this fixation, a part of the bimetal plate 7, the end side of the movable contact support plate 3, and the brass plate 6 are in close contact with each other in this order from below. An insulating layer 10B is provided on the upper surfaces of the brass plate 6 and the fixture 11 to insulate them from the housing section 2.

The bimetal plate 7 is curved downward, and the end opposite to the fixed side is a free end. A movable contact 4 is provided on the opposite end of the movable contact support plate 3 from the fixed side, and in a normal state, the elasticity of the movable contact support plate 3 causes the movable contact 4 to become a fixed contact. 9, the movable contact support plate 3 and the conductive plate 8 are electrically connected, and the switch device 1 is in an ON state. A terminal 3a is located at the end of the movable contact support Fi3 beyond the fixed part (on the right side in the figure), and a terminal 3a is located at the end (on the right side in the figure) of the movable contact support Fi3, which is opposite to the fixed contact 9 of the conductive plate 8.
Terminals 8a are formed at the ends (on the right side in the figure), respectively.
The terminal 3a is connected to the lead wire 12, and the terminal 8a is connected to the lead wire 13. These connections are made as crimp terminals, but the crimp state is not shown.

FIG. 4 is a schematic circuit diagram showing an example of the connection between the switch device 1 and an electric device (a motor in the example shown in this figure).

When the temperature of the electrical equipment increases due to some trouble during use, and the temperature of the switch device 1 rises accordingly, or when a large current flows and the movable contact support plate 3 is heated, the bimetal plate 7 The free end of the bimetal plate 7 moves upward as it deforms, and eventually the free end of the bimetal plate 7 comes into contact with the wear-resistant contact plate 5 provided on the movable contact support plate 3. As the deformation of the bimetal plate 7 further progresses, the third As shown in the figure, the movable contact support plate 3 is pushed by the bimetal plate 7 which has undergone deformation and is bent upward, the movable contact 4 is separated from the fixed contact 9, and the switch device 1 is turned off.

What should be noted in this example is that the following phenomenon occurs in the process of switching device 1 from the ON state to the OFF state. The bimetal plate 7 is curved downward in the ON state shown in FIG. 2, and is deformed so as to be warped upward in the OFF state shown in FIG. 3, contrary to that shown in FIG. In the initial stage when the temperature of the bimetal plate 7 increases from the state shown in Fig. 2 to the state shown in Fig. 3, the bimetal plate gradually deforms as the temperature rises, and once it reaches a predetermined shape, it deforms rapidly. progresses.

That is, the bimetal plate 7 gradually deforms until the amount of deformation reaches the dark value, and when the amount of deformation reaches this dark value, the deformation progresses rapidly. This gradual process of deformation at the initial stage is called creep. After the creep of the bimetal plate 7 has passed, the movable contact support plate 3 is rapidly pushed upward due to the rapid progress of deformation (snap action), and therefore the movable contact 4 quickly separates from the fixed contact 9, causing the contact to close due to the spark. No welding occurs. The dark value of the amount of deformation of the bimetal plate changes depending on the temperature at which the switch device 1 is turned from the ON state to the OFF state, and the higher the temperature, the larger the dark value. Therefore, in FIG. 2, the distance between the free end of the bimetal plate 7 and the movable contact support plate is the same when the switch device 1 is turned on from the ON state to the OFF state.
It may be determined according to the set temperature to be set. In other words, since one end side of the bimetal plate 7 is tightly fixed to the movable contact support plate 3, it is sufficient to select the bimetal plate 7 having a curvature corresponding to the above-mentioned set temperature.

Therefore, there is no need to adjust the distance as described above, assembly is simple, and chattering and contact welding due to errors in adjusting the distance as described above do not occur.

When transitioning from the OFF state in Fig. 3 to the ON state in Fig. 2, the bimetal + lJi 7 is
After passing through the creep step 1, the deformation progresses rapidly, and the movable contact 4 comes into pressure contact with the fixed contact 9. Due to the above-described deformation of the bimetal plate 7, chattering does not occur, the bimetal plate 7 and the movable contact support plate 3 do not become fatigued and do not function normally, and the contacts do not weld, and the switch device 1 does not lose its switch function over a long period of time, and electrical equipment can be reliably protected.

A part of the bimetal plate 7 is in close contact with a part of the movable contact support plate 3, and a part of the movable contact support plate 3 is in close contact with the brass plate 6. Therefore, when the switch device 1 shifts from the OFF state shown in FIG. 3 to the ON state shown in FIG.
Since heat is supplied by conduction from the outside, the temperature decreases slowly, unlike in the case of natural cooling. Therefore, at this time, the time that the switch device 1 is in the OFF state as shown in FIG. 3 becomes longer, and during this time it is convenient to eliminate the cause of abnormality in the electrical Ia equipment, and maintenance of the electrical equipment becomes easier.

5 and 6 show the gripping portion of the electric drill with the above-mentioned switch device removed. FIG. 5 is a side view, and FIG. 6 is a partially fragmented front view.

As shown in FIG. 5, a power switch button 16 protrudes from a through hole provided in the lid 17a on the side surface of the grip portion 17. In the figure, 19 is a fuse box, and 20 is a lever for removing the lid. As shown in the fifth episode, the switch device 1 is attached to the grip part 17 inside the ff117a,
The lead wires 12.13 are connected to the terminals 18A, 18 in the grip 17.
Connected to B.

The switch device based on the present invention can be applied to the protection of various electrical equipment and has a wide range of applications, but is particularly applicable to protection from short circuits of battery backs (including dry cells), and protection of batteries connected directly to the windings of small motors. Suitable for protection against overload.

In addition to the embodiments described above, various modifications can be made based on the technical idea of the present invention. For example, the shape of the bimetal may be an appropriate shape that causes creep, and the mounting position of the movable contact may be an appropriate shape depending on the structure and shape of the switch device. Furthermore, instead of bimetal, other deformable members that deform in response to temperature changes may be used.

In addition to motors and other electrical equipment, the objects to be protected include
The switch device according to the present invention can also be applied to electrically protect or control various machines and devices.

As described above in detail, the switch device according to the present invention has a deformable member that deforms in response to temperature changes and a movable member provided with a movable contact, and a south end separate from the movable contact and a movable member provided with a movable contact. The distance can always be set to a desired distance corresponding to the temperature setting at the time of switch-off tA. Therefore, there is no need to adjust the distance between the deformable member and the movable member as in conventional switch devices, and the set γ is easy to handle. In addition, chattering and contact welding due to errors in this adjustment will not occur, and the maintenance of electrical equipment, etc. will be ensured over a long period of time, resulting in high reliability.

[Brief explanation of the drawing]

1 to 6 show embodiments of the present invention, in which FIG. 1 is an internal plan view of the switch device, FIG. 2 is a sectional view taken along the line II-II in FIG. 1, and FIG. The figure shows a cross-sectional view of the switch device in the OFF state, FIG. 4 is a schematic circuit diagram of the connection between the switch device and the motor, FIGS. 5 and 6 show the grip of the electric drill equipped with the switch device, and FIG. Fig. 5 is a side view, and Fig. 6 is a fragmented front view. 7 to 10 show conventional examples, in which FIG. 7 is an internal plan view of the switch device, FIG. 8 is a sectional view taken along the line ■-■ in FIG. 7, and FIG. 7 is a partially enlarged view of the same, and FIG. 10 is a sectional view of the switch device in the OFF state. In addition, in the symbols shown on the open surface, 1.21......Switch device 3.23...
......Movable contact support plate (movable member) 24...
......Movable contact 6...Brass plate 7.27...Bimetal plate 8.25.2
8... Conductive plate 9.29...
・Fixed contact 11.31...Fixing tool 12.13.32.33...Lead wire 1
4. It is a resin stand.

Claims (1)

[Claims] 1. A switch device in which a movable contact moves due to deformation of a deformable member that deforms in response to temperature changes, and switching is performed between this movable contact and a fixed contact corresponding to this movable contact, in which the movable contact is provided. The movable member and the deformable member are fixed to each other at a position different from the movable contact, an end of the deformable member is configured as a free end, and the movable member is deflected as the deformable member deforms. A switch device characterized in that the movement of the movable contact is performed by the following steps.