JP4203870B2 - Thermally responsive switch - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thermally responsive switch, and in particular, a thermally responsive plate such as a bimetal is less affected by the magnitude of the energized current and is configured to operate substantially at ambient temperature. The present invention relates to a thermally responsive switch.
[0002]
[Prior art]
Conventionally, various protection switches have been used for motors such as air conditioners for protection from overheating and overcurrent in the event of an abnormality. These conventional protection switches have a structure in which the operating current of the motor flows through the thermally actuated plate so as to respond to overheating in the compressor and overcurrent of the motor, and when the ambient temperature rises abnormally or the current value increases. In this case, the operating current was interrupted by the reversal of the thermally responsive plate.
[0003]
In recent years, inverter-controlled motors have been widely used because fine control is easy and efficient as a motor. However, in this inverter-controlled electric motor, it has been extremely difficult to protect with the conventionally used protective switch. In other words, in a conventional motor, the normal operating current is almost constant, so the protection switch is set not to operate at that operating current value, but to operate at an overcurrent when there is an abnormality such as a rotor lock. However, in an inverter-controlled motor, the operating current is changed according to the load even during normal operation. There is a risk of lack of accuracy. Therefore, as a protective switch for the inverter-controlled electric motor, a thermally responsive switch that does not substantially pass an operating current to the thermally responsive plate is used.
[0004]
Conventionally, many proposals have been made for this type of heat responsive switch, but many of them require a relatively large base made of an insulating material such as resin in order to place a heat responsive plate for driving the movable contact. It was difficult to downsize. For example, there is a “thermo switch” described in Japanese Patent Publication No. 56-8456. The switch described here is provided with a bimetal that contacts and separates the movable contact provided on the movable contact support plate from the fixed contact so that no current flows directly through the bimetal. The bimetal is provided with an insertion hole in the center, and is inserted into a support protrusion on the insulating base. In the heat responsive switch having such a structure, a relatively large insulator such as an insulating base is required in order to insulate and hold the bimetal which is a metal plate.
[0005]
However, when the switch container is an airtight sealed container, it is not preferable to put an insulator, particularly a large one, inside the container. This is because if the insulator is a resin, there is a possibility that some gas may be generated from the resin when it is used in a closed container for a long time. This is because there is a possibility that the conductivity between the contacts may be impaired by changing the composition of the sealed gas in the selected switch or causing a chemical change on the contact surface. In addition, when ceramics are used, the possibility of gas generation is reduced, but it is difficult to fix to metal parts. In both cases, the heat capacity increases, so the responsiveness as a thermally responsive switch decreases. There's a problem.
[0006]
For example, as an example in which the amount of the insulator is reduced, Japanese Patent Application Laid-Open No. 1-302628 discloses a “switch device” in which a bimetallic thermal response switch is housed in a metal housing (container). Yes. In this switch device, one end of a bimetal plate is fixed to a fixed portion of a movable contact support plate, and the movable contact support plate is driven when the bimetal plate is inverted at a predetermined temperature.
[0007]
However, since this switch device is arranged so that an insulating plate is sandwiched between a conductive portion such as a fixed contact and a metal housing portion, there is a problem that workability at the time of assembly is poor. Further, this switch device is not an airtight structure, but only a metal container and a resin base are brought into close contact with each other. For example, there is a method of filling the opening of the container with resin or the like as shown here as a conventional example in this publication, but in such a simple sealed structure, the composition of the sealed gas is kept constant over a long period of time. It is impossible to keep.
[0008]
An example of a completely sealed structure is a “thermal protector” disclosed in Japanese Patent Publication No. 2-21088. In this protector, a fixed electrode and a movable electrode are opposed to each other in a glass container, and the movable electrode is driven by a thermally responsive element plate. This protector has a structure in which a thermally responsive element plate and a metal elastic piece as a movable electrode are welded and fixed together with a contact on the movable end side, and the other end of the thermally responsive element plate is held during reversal. Therefore, when the thermally responsive element plate is reversed, the side to which the movable contact is fixed is driven against the biasing force of the metal elastic piece to separate the contacts. In this thermal protector, since the bimetal is fixed by welding, there is a problem that the inversion and return temperature of the bimetal changes before and after assembly. This thermal protector has a high airtightness due to the use of a glass container. For example, when a heat-responsive switch is used in a sealed housing of a hermetic electric compressor, Requires special attention.
[0009]
In the above-mentioned “switch device” and “thermal protector”, both use the thermal reaction plate in a cantilevered state, so if an attempt is made to set the contact pressure high, the burden on the thermal reaction plate increases, and the thermal There is a problem that the operating temperature and the return temperature applied when only the plate is changed by applying the contact pressure.
[0010]
Furthermore, the “thermal protection switch” disclosed in Japanese Patent Application Laid-Open No. 55-148331 shows one that is fixed to the spring snap plate by a contact point that is inserted through a hole penetrating through the center of a bimetal snap plate that is a thermally responsive plate. ing. This thermal protection switch also drives the movable contact against the biasing force of the spring snap plate when the thermal reaction plate is reversed, but the force at the time of reversal is because the contact is located in the center of the thermal response plate. Since it is dispersed in the peripheral portion of the thermal reaction plate, the burden on the thermal reaction plate can be reduced as compared with the cantilever type.
[0011]
However, this thermal protection switch is one in which the casing base and casing lid are fixed by a method such as caulking with an insulator sandwiched between them, and is completely different from the configuration for making an airtight structure in the strict sense intended by the present application. Is different. Further, since the inner surface of the casing lid itself is a fixed contact, the force applied to the bimetal changes even if the casing is slightly deformed, and there is a problem that the operating temperature and the return temperature as a switch change.
[0012]
[Problems to be solved by the invention]
As described above, conventionally proposed thermal responsive switches having a structure in which no current flows through the thermal responsive plate are particularly suitable for use in a high pressure such as in a sealed housing of a hermetic electric compressor. Therefore, there has been a demand for a thermally responsive switch having a container having high airtightness and pressure resistance, good thermal response and high mass productivity. In order to solve this problem, the present applicant has applied for a “thermally responsive switch” in Japanese Patent Application No. 9-322244. However, in order to reduce the size of this thermally responsive switch, a very thin metal plate is used so that the movable plate to which the movable contact is attached can operate in accordance with the movement of the bimetal. If the movable plate is thin, distortion due to plastic deformation may occur when the movable contact is attached, welded to the conductive base, or when the movable plate is subjected to bending stress when operated as a switch. However, there is a problem that the contact pressure between the movable contact and the fixed contact and the distance between the contacts at the time of opening do not fall within a predetermined range.
[0013]
[Means for Solving the Problems]
The present invention relates to an improvement of Japanese Patent Application No. 9-322244.
[0014]
Its feature is that it has a bottomed cylindrical metal container and a metal plate provided with a through hole, and the lead plate pin is electrically insulated from the through hole of this metal plate. A cover plate is formed by being fixed through, and the cover plate is hermetically fixed to the opening end of the container by welding to form an airtight container, which is drawn into a shallow dish and provided with a through hole in the center. The thermally responsive plate performs a reversal and return operation at a predetermined temperature to contact or open the movable contact with the fixed contact, and a fixed contact portion is provided in the airtight container of the lead terminal pin. A highly rigid movable plate support is fixed to the inner surface of the hermetic container of the metal plate, and one end serving as a fixed portion of the movable plate having flexible elasticity is fixed to the movable plate support. Made of a conductive metal plate, the end opposite the fixed part at all times A biasing force is applied so that the corresponding free end side is pressed against the movable plate support side. A movable contact is fixed to the free end side of the movable plate, and a member fixed to the free end side of the movable plate is heated. In a thermally responsive switch in which both are connected so that the movable plate is driven by the thermally responsive plate by being loosely fitted and held in the through hole of the responsive plate, the free end of the movable plate has a heat A through-hole that is slightly smaller in diameter than the through-hole provided in the response plate is provided, and the movable contact has one end as a large diameter portion and the other end as a small diameter portion, and at least a thermal response is provided between the large diameter portion and the small diameter portion. A thermally responsive plate loosely fitting portion having a diameter that passes through the through hole of the plate but cannot be inserted into the through hole of the movable plate is provided, and the small diameter portion of the movable contact is inserted through the through hole of the thermally responsive plate and the movable plate. The tip of the movable contact small diameter portion is deformed and the heat responsive plate loosely fitting portion The movable plate is sandwiched and fixed between the end faces, it lies in the loosely holding the thermally responsive plate in thermally responsive plate loosely fitting portions of the movable contact.
[0015]
Yet another feature is that a free-side end of the movable plate is provided with a through-hole that is slightly smaller in diameter than the through-hole provided in the thermally responsive plate, and the movable contact consists of a contact member and a thermally responsive plate loose-fitting member. The contact member has one end as a contact portion, and the contact member is welded to the distal end of the thermally responsive plate loosely fitting portion inserted through the through hole of the thermally responsive plate via the through hole of the movable plate. The movable contact is in a thermally responsive switch that holds and fixes the movable plate around the welded portion and loosely holds the thermally responsive plate by the thermally responsive plate loosely fitting portion.
[0016]
Another feature is that it has a movable contact and a thermally responsive plate loose fitting member, and the movable contact is directly fixed to the movable plate by welding. The thermally responsive plate loosely fitted member has one end having a large diameter and the other end is a thermally responsive plate. The thermally responsive plate loosely fitting portion is inserted into the through hole of the thermal responsive plate, and the thermally responsive plate loosely fitted portion is inserted into the through hole of the thermally responsive plate. The surface where the movable contact is welded The tip of the thermally responsive plate loosely fitting portion is welded to the back surface so that the thermally responsive plate is connected to the movable plate and loosely held.
[0017]
Furthermore, in the thermally responsive switch of the present invention, a through hole having a diameter slightly smaller than the through hole of the thermally responsive plate is provided on the free end side of the movable plate, and the movable contact has one end as a large diameter portion and the other end as a small diameter portion. In addition, a thermal reaction plate loose fitting portion having a diameter that passes through at least the through hole of the thermal reaction plate but cannot be inserted into the through hole of the movable plate is provided between the large diameter portion and the small diameter portion, The movable contact inserted through the through hole of the movable plate has a movable plate welded and fixed to the end face of the thermally responsive plate loosely fitting portion, and the thermally responsive plate is loosely fitted and held by this thermally responsive plate loosely fitted portion. And
[0018]
Another feature is that the small-diameter portion of the movable contact is inserted through a reinforcing plate having a through hole together with the thermally responsive plate and the movable plate, and the movable contact is connected to the end surface of the thermally responsive plate loosely fitting portion via the reinforcing plate. This is because the movable plate is fixed.
[0019]
Yet another feature is that a fixed plate for preventing deformation around the fixed portion is welded to the fixed portion of the movable plate so as to sandwich the movable plate with the movable plate support.
[0020]
In addition, an electrically insulating positioning member is inserted between the movable plate support to which the movable plate of the thermally responsive switch is fixed and the fixed contact portion, and the positioning member is sandwiched between the movable plate support and the fixed contact portion. The positional relationship between the movable contact and the fixed contact is defined.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the thermally responsive switch of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of an embodiment of a thermally responsive switch according to the present invention, FIG. 2 is a transverse sectional view thereof, and FIG. 3 is a sectional view taken along the line AA of FIG. Further, FIG. 4 shows a movable contact used in the present invention, and FIG. 5 shows an exploded perspective view of a thermally responsive switch in which a container is omitted.
[0022]
This heat responsive switch 1 is hermetically sealed by a metal container 2 having a bottomed cylindrical shape with one of the cylinders closed, a metal plate 3A and its through hole 3B, and an insulating filler 4 such as glass. The cover plate 3 is composed of the lead terminal pins 5 fixed to each other. The opening end of the container 2 is hermetically fixed to the vicinity of the peripheral edge of the metal plate 3A of the cover plate 3 by welding or the like over the entire circumference, and both constitute an airtight container. A gas mixture containing a gas having a composition selected from the viewpoint of thermal conductivity and the like is sealed inside the hermetic container, and this hermetic structure can keep the composition without changing over a long period of time. For example, in the embodiment, helium gas having good thermal conductivity in the sealing gas is 75% in the volume ratio, and 25% is nitrogen, but this helium content is 10% or more from the viewpoint of thermal conductivity. In addition, if the concentration of helium is too high, the withstand voltage between contacts in the contact open state is lowered, so 90% or less is preferable.
[0023]
A substantially prismatic fixed contact portion 6 is conductively fixed to the end portion of the lead terminal pin 5 of the lid plate 3 on the inner side of the hermetic container. In this embodiment, the lead terminal pin 5 and a separate fixed contact portion 6 are provided as an example. However, for example, the lead terminal pin 5 is extended to be able to contact and separate from a movable contact described later. It is good also as a structure which makes the vicinity of a front-end | tip a fixed contact part by processing to a crank shape so that it may become, or attaching eccentrically with respect to 3A of metal plates.
[0024]
One end of a movable plate support 7 having high rigidity is fixed on the metal plate 3 </ b> A of the lid plate 3. The movable plate support 7 is composed of a metal plate having a space portion 7B in the center so as to maintain a necessary insulation distance from the lead terminal pin 5 and the fixed contact portion 6, and the fixed side end portion 7A is bent to form L. It is shaped like a letter and is provided so as to be substantially parallel to the fixed contact portion 6 as a whole. One end of a movable plate 8 which is a flexible elastic plate is fixed to the movable plate support 7 by welding or the like at two attachment portions 8A. The movable plate 8 is made of a plate spring-like conductive metal plate, and is given a biasing force so as to always press the tip 8B against the movable plate support.
[0025]
The movable plate 8 uses a thin metal plate in order to achieve both a smooth movement in accordance with a reversing operation of a thermal response plate, which will be described later, and a downsizing of the switch. For this reason, simply welding at the mounting portion 8A causes bending stress to concentrate around the mounting portion 8A of the movable plate during operation of the thermally responsive plate, causing the movable plate 8 to be plastically deformed, and the above-described biasing force is reduced from the initial value. there's a possibility that. Therefore, in order to prevent this, a bending plate 11 having sufficient strength compared to the movable plate is arranged on the fixed portion during welding of the movable plate 8, in this embodiment the mounting portion 8A, by welding or the like, and the bending stress is concentrated on the mounting portion. It is preferable to prevent deformation due to, and suppress a decrease in biasing force.
[0026]
A through hole 8C is provided in the vicinity of the distal end portion 8B of the movable plate 8, and the movable contact 9 is fixed to the through hole by caulking or the like. As shown in FIG. 4 (A), the movable contact 9 has a relatively large-diameter head 9A at one end and a cylindrical small-diameter portion 9B at the other end. Between them, there is a thermally responsive plate loosely fitting portion 9C having a diameter smaller than the diameter of the head and larger than the diameter of the small diameter portion. The thickness from the head end surface 9D to the loose fitting portion end surface 9E of the loose fitting portion 9C is set to be larger than the thickness of the thermally responsive plate 10 described later. The movable contact 9 is fixed to the movable plate 8 by caulking work such as pressing, and the tip of the small diameter portion 9B is formed as shown in FIG. The Further, the movable contact 9 is made of a contact material such as silver or a silver alloy for contact with the fixed contact portion 6, but when the fixing work is performed by caulking as described above, the head 9A and the loose fitting portion are provided. For 9C, it is preferable to use a harder material than the small-diameter portion 9B because the fixing work becomes easier.
[0027]
The thermally responsive plate 10 is formed by drawing a heat-deformed metal plate such as a bimetal or a trimetal into a shallow dish shape, suddenly reverses the curve direction at a predetermined first temperature, and returns suddenly at a second temperature. To do. A through hole 10A for inserting the movable contact 9 is formed in the vicinity of the center of the diaphragm of the thermally responsive plate 10, and four slits 10B are provided radially from the through hole 10A in this embodiment. The through hole 10A has a diameter larger than that of the through hole 8C formed in the movable plate 8 described above. Further, since the portion sandwiched between these slits 10B becomes an arm 10C that enlarges the displacement amount of the surroundings, the moving amount of the movable contact 9 can be made larger than that without the slit, so You can increase the distance. Further, if the apparent distance between the contacts is the same, the amount of deviation of the movable contact 8 toward the fixed contact portion 6 increases, and as a result, the contact pressure between the contacts can be increased.
[0028]
Here, the assembly of the movable contact 9, the movable plate 8, and the thermally responsive plate 10 will be described. First, the small diameter portion 9 </ b> B of the movable contact 9 is inserted into the through hole 10 </ b> A of the thermally responsive plate 10. Here, the inner diameter of the through hole 10A is set to be slightly larger than the outer diameter of the loosely fitting portion 9C of the movable contact, and the thermally responsive plate 10 contacts the head end surface 9D of the movable contact 9. Next, the small diameter portion 9 </ b> B is inserted into the through hole 8 </ b> C of the movable plate 8. The through hole 8C of the movable plate is slightly smaller in diameter than the through hole 10A of the thermally responsive plate, and further smaller than the outer diameter of the loose fitting portion 9C of the movable contact. Touch.
[0029]
In this embodiment, a washer 12 is attached as a reinforcing plate after the movable contact 9 is inserted into the movable plate 8. This washer 12 is a metal plate having sufficient thickness and strength so as not to be deformed by caulking work of the movable contact. The washer 12 comes into contact with the periphery of the through hole 8C of the movable plate and is caused by a bias of force during the caulking process. Reinforce so that no distortion of 8 occurs. The washer 12 is not necessarily required unless distortion due to deformation becomes a problem. For example, a washer can be omitted by providing a slit around the crimped portion of the movable plate to release distortion due to deformation, or by increasing the thickness while keeping the flexible plate long and flexible.
[0030]
In this embodiment having a washer as a reinforcing plate, after the movable contact 9 is inserted into the thermally responsive plate 10, the movable plate 8, and the washer 12, the tip of the movable contact small diameter portion 9B is pressed into a portion shown in FIG. The contact portion 9F is formed by being deformed as shown. The contact portion 9F holds the washer 12 as its diameter increases before processing, and the peripheral portion of the through hole 8C of the movable plate 8 is fixed by caulking from the upper and lower surfaces with the washer 12 and the loose fitting end surface 9E of the movable contact. Here, the thermally responsive plate 10 is located in the loosely fitting portion 9C of the movable contact, and the loosely fitted portion 9C is thicker than the thermally responsive plate 10 as described above. Since it does not substantially deform, the thermally responsive plate 10 is loosely fitted and held so that its movement is not restricted. Therefore, the operating temperature at which the thermoresponsive plate 10 jumps and reverses at the above-described predetermined first temperature does not change due to the assembly. That is, the operating temperature of the thermal reaction plate 10 as a single unit and the operation temperature after being incorporated in the thermal response switch 1 coincide. For this reason, in the case of a conventional heat responsive switch having a structure in which some force is applied to the heat responsive plate, the operation temperature after the switch assembly is required because the operation temperature changes between the heat responsive plate alone and after the switch is assembled. Verification or calibration operations can be omitted in the thermally responsive switch of the present invention.
[0031]
In the present invention, since all the parts constituting the circuit of the switch are arranged on the cover plate, it is possible to directly confirm the positional relationship of each part and the operation of the switch mechanism before the container 2 is fixed to the cover plate 3. it can. Here, when adjustment of the contact pressure between the movable contact 9 and the fixed contact portion 6 and the distance between the contacts at the time of opening is necessary, the movable plate support 7 or the fixed contact portion 6 is bent to The positional relationship between the surface on which the movable contact head end surface 9D abuts and the contact surface of the fixed contact portion 6 is adjusted. In the heat responsive switch 1 of the embodiment, this adjustment operation is performed by displacing the tip 7C of the movable plate support 7 in the vertical direction in FIG. In this embodiment, as shown in FIGS. 2 and 5, the movable plate support 7 is provided with a width detail 7D in the vicinity of the fixed side end portion 7A with the lid plate so as to be easily deformed during adjustment. Since the adjustment is made without deforming the distal end side from the mounting portion 8A, the adjustment work can be reliably performed without changing the biasing force previously applied to the movable plate 8.
[0032]
Next, the operation of the thermally responsive switch 1 will be described with reference to cross-sectional views showing the operation states of FIGS. Normally, the bending direction of the thermally responsive plate 10 is convex toward the movable plate 8 as shown in FIG. 1, and the movable contact 9 is fixed to the fixed contact portion 6 by a biasing force applied to the movable plate 8. It is contacted by contact pressure. Therefore, the electric path by the conductive terminal pin 5 -the fixed contact portion 6 -the movable contact 9 -the movable plate 8 -the movable plate support 7 -the cover plate 3 is closed. Here, when the case where this thermal responsive switch is attached to the electric motor is considered as an example, even when an electric current flows through the electric circuit, the electric operating current of the electric motor does not substantially flow through the thermal responsive plate 10, so The influence on the operating temperature due to the self-heating of the plate 10 is negligible. In addition, since a gas mixture with good thermal conductivity containing helium is sealed in a sealed container, heat generated in the electric circuit is released to the outside through the gas mixture and the container during normal times, that is, when the ambient temperature is low. Therefore, the thermally responsive plate 10 is not reversed by Joule heat due to the resistance of the electric circuit.
[0033]
Here, for example, when the electric motor is overheated for some reason, the ambient temperature of the heat responsive switch 1 rises, and this heat is transmitted to the inside of the sealed container through the container and the mixed gas. As a result, when the thermally responsive plate 10 reaches a predetermined first temperature, the thermally responsive plate 10 jumps over and reverses its direction of curvature as shown in FIG. Therefore, both end portions of the thermally responsive plate 10 are brought into contact with the movable plate support 7 directly or via the movable plate 8, and the movable contact 9 located at the center is moved against the biasing force of the movable plate 8 to contact the contact portion 9F. Is disconnected from the fixed contact portion 6 to interrupt the electric circuit.
[0034]
In the above-described embodiment, the movable contact is fixed to the elastic plate by caulking, but may be fixed by welding instead of caulking. This example will be described with reference to FIG. The same parts as those of the above-described thermally responsive switch 1 are denoted by the same reference numerals, and detailed description thereof is omitted. In this thermally responsive switch 21, the movable contact 29 is inserted into the thermally responsive plate 10 and the movable plate 8 and then the movable contact 29 and the movable plate 8 are fixed by welding. This movable contact 29 has a relatively large-diameter head 29 at one end, a cylindrical small-diameter portion 29B at the other end, and a thermally responsive plate between the head and the small-diameter portion. A loose fitting portion 29C is provided. The tip of the small-diameter portion 29B does not require pressing as in the above-described movable contact, and has already been shaped as a contact portion before assembly.
[0035]
The thermally responsive plate 10 having a through hole larger than the movable plate 8 is inserted through the loose fitting portion 29C, and the movable plate 8 contacts the loose fitting portion end surface 29E. Here, the loose fitting portion end face 29E is welded to the movable plate 10 to fix both of them, and by making the thickness of the loose fitting portion 29C thicker than that of the thermally responsive plate 10, the movement of the thermal responsive plate 10 is not restricted. So as to be loosely fitted. For example, when distortion caused by deformation that occurs during welding becomes a problem for the operation of the movable plate, the deformation may be suppressed by welding while applying a reinforcing plate such as a washer to the welded portion. You may provide the slit for releasing deformation distortion around a welding part.
[0036]
In addition to the contact structure described above, for example, a structure shown in FIGS. 8A and 8B may be used. In FIG. 8A, the movable contact 31 is divided into a contact member 31A and a thermally responsive plate loose fitting member 31B, and these members are connected to the through holes 8C and 10A of the movable plate 8 and the thermally responsive plate 10, respectively. The movable plate 8 and the thermally responsive plate 10 are sandwiched and fixed by both members 31A and 31B of the movable contact at the time of welding. Further, in the embodiment of FIG. 8B, a movable plate 48 having no through-hole is used, and a movable contact 41 is welded to the lower surface of the movable plate 48 in the figure, and on the rear surface of the movable plate, that is, the upper surface in the figure. Is welded to a position substantially corresponding to the movable contact 41 with a thermally responsive plate loosely fitting member 42 having a large diameter portion and a thermally responsive plate loosely fitted portion. In the embodiment of FIG. 8B, for example, the energization path can be shortened by offsetting the welding position between the thermally responsive plate loosely fitting member and the movable contact, and heat generation on the energization path can be reduced. 8A and 8B, the heat responsive plate 10 is loosely held by the heat responsive plate loose fitting portions in the through holes 10A and is connected to the free end of the movable plate 8 as described above. This is the same as each of the examples.
[0037]
In this embodiment, the contact pressure between the contacts is adjusted by deforming the movable plate support as described above. In other words, this is to define the positional relationship between the movable plate support and the fixed contact. However, when the movable plate support is deformed, so-called spring back is also generated. Therefore, this adjustment work needs to be performed in consideration of this point, and the workability is poor. Further, in order to eliminate the adjustment work, it is necessary to manage the dimensional tolerance of each part and the dimensional tolerance at the time of assembly very strictly, which is difficult.
[0038]
FIG. 9 shows an improvement made to facilitate this adjustment work. Also in this embodiment, the same parts as those in the above-described embodiments are denoted by the same reference numerals, and detailed description thereof is omitted. The thermally responsive switch 51 of this embodiment has a fixed contact 56 extending along the movable plate support 7 and is made of an insulator for defining the distance between the two near the tip. A positioning member 52 is disposed. Next, adjustment work by this configuration will be described. In the embodiment, the fixed contact portion 56 and the movable plate support 7 are assembled on the lid plate with their tip portions approaching each other in advance so as to increase the contact pressure between the contacts. Instead of deforming either member, a positioning member 52 having a predetermined thickness is sandwiched between the two members.
[0039]
In the embodiment, as shown in the drawing, the positioning member 52 has a wedge shape with respect to the insertion direction, and both ends are touched to the movable plate support 7 from the front to the back of the drawing. As described above, the positioning member 52 inserted between the fixed contact portion 56 and the movable plate support 7 has the upper end in the drawing at the top end of the movable plate support 7. 7C The lower surface of the center portion is in contact with the vicinity of the front end portion of the fixed contact portion 56. The positioning member is sandwiched between the fixed contact portion and the movable plate support member, but is more reliably held by providing a detent on either member. By using the positioning member in this way, the gap between the two members that is narrower than the appropriate value is expanded to a predetermined positional relationship. Thus, according to the present embodiment, the adjustment work is completed simply by inserting and positioning the positioning member 52 between the fixed contact and the movable plate support, and the work can be greatly simplified.
[0040]
In the embodiments described so far, a container having a closed cylindrical shape is used as the container. However, this shape is not limited to the cylindrical shape, for example, a container 62 of the thermally responsive switch 61 shown in FIG. The cross-sectional shape may be a cylindrical container other than a circle such as an ellipse. Hereinafter, although this thermal responsive switch 61 is demonstrated, the same code | symbol is attached | subjected to the same part as the above-mentioned thermal responsive switch 1, and detailed description is abbreviate | omitted. In this thermal responsive switch 61, the cross-sectional shape of the container 62 is elliptical, so that the metal plate 63A of the lid plate 63 that is in contact with and fixed to the opening is also elliptical. The movable plate support 67 has a fixed side end 67 </ b> A that is fixed to the metal plate 63 so that the height is suppressed along the inner peripheral surface of the container 62. Except for these points, the operation is the same as that of the above-described thermally responsive switch 1 including its operation.
[0041]
Thus, by making the cross-sectional shape of the container elliptical, the distance between the container 62 and the thermally responsive plate 10 becomes closer than that of the circular cross-section described above, so that the thermal response of the thermally responsive plate 10 to ambient temperature changes. Sexuality is improved. In addition, it is easy to attach to the heating element, and the orientation of the thermal reaction plate can be known from the shape of the container even after the sealed container is configured, so it can be attached so that the thermal reaction plate faces the heating element. It becomes easy and thermal response can be further improved.
[0042]
In the above description of each embodiment, the through holes of the movable plate and the thermally responsive plate, and the movable contact portion inserted through these through holes are assumed to be circular. Needless to say, the equivalent effect can be obtained by replacing an ellipse or polygon with a diameter or a thickness.
[0043]
【The invention's effect】
According to the thermally responsive switch of the present invention, even when it is used for an inverter-controlled motor whose current changes according to the load, the change in the operating current has little influence on the operating conditions and the external temperature change Therefore, it is possible to provide a straight-cut switch that can cope with the above with a simple structure.
[0044]
In addition, by placing a contact plate or washer to disperse the stress on the part where welding or caulking force is applied to the movable plate during assembly, the movable plate is less likely to be distorted, making a thinner and more flexible metal plate. Can be used. In addition, when an electric circuit is formed by a fixed contact and a movable contact, regardless of the contact pressure between the two contacts, no external force is applied to the heat responsive plate. It is possible to match the operating temperature given at the time of the operation, and the operation temperature confirmation work after the switch is completed can be omitted.
[0045]
In addition, since the airtight container has a structure in which the lid plate is tightly sealed to the opening of the metal bottomed cylindrical container by a method such as welding, high airtightness and pressure resistance can be easily obtained. . As a result, by enclosing a gas having a desired composition in the space in the hermetic container, the thermal conductivity between the thermally responsive plate and the container, and the withstand voltage in a state where the movable contact and the fixed contact are open. Can be selected.
[0046]
In addition, by arranging all the components that make up the circuit of the switch on the cover plate, the positional relationship of each part and the operation of the switch mechanism before the airtight container is formed in the manufacturing process, that is, before the cover plate and the container are fixed. Can be confirmed directly, making assembly work easier. Further, in this manufacturing process, a positioning member of a predetermined size is sandwiched between the fixed contact and the movable plate support, and the positional relationship between the fixed contact and the movable contact is set to a predetermined value, so that complicated adjustment work is performed. Can be omitted.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an embodiment of a thermally responsive switch of the present invention.
2 is a cross-sectional view of the thermally responsive switch of FIG.
3 is a cross-sectional view taken along the line AA of the thermally responsive switch of FIG. 1;
FIG. 4 shows another embodiment of the movable contact used in the thermally responsive switch of the present invention.
5 is an exploded perspective view of the thermally responsive switch of FIG. 1 with the container 2 removed.
6 is a longitudinal sectional view showing the operating state of the thermally responsive switch of FIG. 1. FIG.
FIG. 7 shows another embodiment of the thermally responsive switch of the present invention.
8 shows another embodiment of the movable contact used in the thermally responsive switch of FIG.
FIG. 9 shows another embodiment of the present invention.
FIG. 10 shows another embodiment of the thermally responsive switch of the present invention.
[Explanation of symbols]
1, 21, 51, 61: Thermally responsive switch
2,62: Container
3, 63: Cover plate
5: Lead terminal pin
6: Fixed contact
7, 67: Movable plate support
8: Movable plate
8C: Through hole
9, 29, 31, 41: movable contact
9A: head
9B: Small diameter part
9C: Free fitting part
9D: head end face
9E: Free fitting part end surface
9F: contact part
10: Thermally responsive plate
10A: Through hole
10B: Slit
10C: Arm
11: Address plate
12: Washer (reinforcement plate)
42: Thermally responsive plate loose-fitting member
52: Positioning member

Claims (7)

A bottomed cylindrical metal container,
Having a metal plate provided with through holes,
In the state where the conductive lead terminal pin is electrically insulated in the through hole of the metal plate, the cover plate is configured to be hermetically penetrated and fixed.
An airtight container is configured by fixing the lid plate in an airtight manner to the opening end of the container by welding,
A thermally responsive plate that is drawn into a shallow dish shape and has a through hole at the center performs inversion and return operations at a predetermined temperature, thereby bringing the movable contact into contact with or separating from the fixed contact,
A fixed contact portion is provided in the airtight container of the lead terminal pin,
A highly rigid movable plate support is fixed to the inner surface of the hermetic container of the metal plate of the lid plate,
One end of the movable plate having supple elasticity is fixed to the movable plate support as a fixed portion,
This movable plate is made of a conductive metal plate in the form of a leaf spring, and a biasing force is applied so that the free end side, which is the end opposite to the fixed portion, is always pressed against the movable plate support.
A movable contact is fixed to the free end of the movable plate,
Further, in the thermally responsive switch in which the movable contact is inserted into the through hole of the thermally responsive plate and the thermally responsive plate is loosely fitted and held so that the movable plate is driven by the thermally responsive plate,
On the free end side of the movable plate, a through hole having a diameter smaller than the through hole provided in the thermally responsive plate is provided,
The movable contact has a large diameter portion at one end and a small diameter portion at the other end. Between the large diameter portion and the small diameter portion, the movable contact has a diameter that passes through at least the through hole of the thermally responsive plate but cannot be inserted into the through hole of the movable plate. A heat-responsive plate loose fitting part is provided,
The small-diameter portion of the movable contact is inserted through the thermally responsive plate and the through hole of the movable plate,
The tip of the movable contact small-diameter portion is deformed and the movable plate is sandwiched and fixed with the end face of the thermally responsive plate loose fitting portion,
A thermally responsive switch, wherein the thermally responsive plate is loosely held in a thermally responsive plate loosely fitting portion of a movable contact. A bottomed cylindrical metal container,
Having a metal plate provided with through holes,
In the state where the conductive lead terminal pin is electrically insulated in the through hole of the metal plate, the cover plate is configured to be hermetically penetrated and fixed.
An airtight container is configured by fixing the lid plate in an airtight manner to the opening end of the container by welding,
A thermally responsive plate that is drawn into a shallow dish shape and has a through hole at the center performs inversion and return operations at a predetermined temperature, thereby bringing the movable contact into contact with or separating from the fixed contact,
A fixed contact portion is provided in the airtight container of the lead terminal pin,
A highly rigid movable plate support is fixed to the inner surface of the hermetic container of the metal plate of the lid plate,
One end of the movable plate having supple elasticity is fixed to the movable plate support as a fixed portion,
This movable plate is made of a conductive metal plate in the form of a leaf spring, and a biasing force is applied so that the free end side, which is the end opposite to the fixed portion, is always pressed against the movable plate support.
A movable contact is fixed to the free end of the movable plate,
Further, in the thermally responsive switch in which the movable contact is inserted into the through hole of the thermally responsive plate and the thermally responsive plate is loosely fitted and held so that the movable plate is driven by the thermally responsive plate,
On the free end side of the movable plate, a through hole having a diameter smaller than the through hole provided in the thermally responsive plate is provided,
The movable contact consists of a contact member and a thermally responsive plate loose fitting member,
This contact member has one end as a contact portion,
The contact member is welded through the through hole of the movable plate to the distal end of the thermally responsive plate loosely fitting portion of the thermally responsive plate loosely fitting member inserted through the through hole of the thermally responsive plate,
A thermally responsive switch characterized in that the movable contact has a movable plate sandwiched and fixed around its welded portion, and the thermally responsive plate is loosely fitted and held by a thermally responsive plate loosely fitting portion. A bottomed cylindrical metal container,
Having a metal plate provided with through holes,
In the state where the conductive lead terminal pin is electrically insulated in the through hole of the metal plate, the cover plate is configured to be hermetically penetrated and fixed.
An airtight container is configured by fixing the lid plate in an airtight manner to the opening end of the container by welding ,
The movable contact contacts or separable with the fixed contact by shallow is dish-shaped to draw forming and thermally responsive plate provided with through holes substantially centered performs inversion and return operation at a predetermined temperature,
A fixed contact portion is provided in the airtight container of the lead terminal pin,
A highly rigid movable plate support is fixed to the inner surface of the hermetic container of the metal plate of the lid plate,
One end of the movable plate having supple elasticity is fixed to the movable plate support as a fixed portion,
This movable plate is made of a plate spring-like conductive metal plate, and a biasing force is applied so that the free end side corresponding to the end opposite to the fixed portion is always pressed against the movable plate support side.
A movable contact is fixed to the free end of the movable plate,
In addition, a thermally responsive plate loosely fitted member fixed separately from the movable contact on the free end side of the movable plate is inserted into the through hole of the thermally responsive plate, and the thermally responsive plate is loosely fitted and held so that the movable plate is driven by the thermally responsive plate. In a thermally responsive switch in which both are connected,
The movable contact is fixed directly to the movable plate by welding,
The thermally responsive plate loosely fitting member has a large diameter portion at one end and a thermally responsive plate loosely fitted portion inserted into the through hole of the thermally responsive plate,
The thermal reaction plate loose-fitting part is inserted through the through hole of the thermal reaction plate,
The tip of the thermally responsive plate loosely fitting portion is welded to the back surface of the surface on which the movable contact of the movable plate is welded, so that the thermally responsive plate is connected to the movable plate and held loosely. Thermally responsive switch. A bottomed cylindrical metal container,
Having a metal plate provided with through holes,
In the state where the conductive lead terminal pin is electrically insulated in the through hole of the metal plate, the cover plate is configured to be hermetically penetrated and fixed.
An airtight container is configured by fixing the lid plate in an airtight manner to the opening end of the container by welding ,
The movable contact contacts or separable with the fixed contact by shallow is dish-shaped to draw forming and thermally responsive plate provided with through holes substantially centered performs inversion and return operation at a predetermined temperature,
A fixed contact portion is provided in the airtight container of the lead terminal pin,
A highly rigid movable plate support is fixed to the inner surface of the hermetic container of the metal plate of the lid plate,
One end of the movable plate having supple elasticity is fixed to the movable plate support as a fixed portion,
This movable plate is made of a conductive metal plate in the form of a leaf spring, and a biasing force is applied so that the free end side, which is the end opposite to the fixed portion, is always pressed against the movable plate support.
A movable contact is fixed to the free end of the movable plate,
Further, in the thermally responsive switch in which the movable contact is inserted into the through hole of the thermally responsive plate and the thermally responsive plate is loosely fitted and held so that the movable plate is driven by the thermally responsive plate,
On the free end side of the movable plate, a through hole having a diameter slightly smaller than the through hole of the thermally responsive plate is provided,
The movable contact has a large diameter portion at one end and a small diameter portion at the other end. Between the large diameter portion and the small diameter portion, the movable contact has a diameter that passes through at least the through hole of the thermally responsive plate but cannot be inserted into the through hole of the movable plate. Provided with a heat responsive plate loose fit,
The movable contact inserted through the through hole of the thermally responsive plate and the movable plate is fixed by welding the movable plate to the end face of the thermally responsive plate loosely fitting portion,
A heat responsive switch, wherein the heat responsive plate is loosely held by the heat responsive plate loosely fitting portion. The small-diameter portion of the movable contact is inserted through a reinforcing plate having a through hole together with the thermally responsive plate and the movable plate,
The thermally responsive switch according to claim 1 or 4, wherein the movable contact fixes the movable plate to an end face of the thermally responsive plate loosely fitting portion via the reinforcing plate.   6. The fixing part of the movable plate is welded so as to sandwich a movable plate between the movable plate and the movable plate support so as to prevent deformation around the fixed part. Thermally responsive switch according to item.   An electrically insulating positioning member is inserted between the movable plate support to which the movable plate is fixed and the fixed contact portion, and the movable contact and the fixed contact are sandwiched between the movable plate support and the fixed contact portion. The thermal responsive switch according to any one of claims 1 to 6, characterized in that a positional relationship between the thermal responsive switch and the switch is defined.

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