JPH0536335A - Heat-reactive switch and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a closed type heat-responsive switch having a long life and a stable quality which is compact, which can be easily manufactured, and with which calibartion of an operating temperature can be performed precisely. CONSTITUTION:A conductive body 3 is fixed to a hole 2A provided in a header plate 2 of metal by an electric insultion filler material 4 penetrating the header plate. A fixed contact 9 is fixed to the header plate. A movable contact 8 is fixed to one end of a heat-responsive plate 7 which changes its curving direction like a snap corresponding to a temperature, and the other end is fixed to around a center of a heat-responsive plate support body. One end of the heat-responsive plate support body is fixed to set a position relation between the fixed contact and the movable contact to be proper. A calibration member 6 is inserted the other end of the heat-responsive plate support body, and the position of each part is checked or adjusted. The header plate is then welded with an aperture part of a cover 1 of metal shaped like a long dome to from a closed container, and by deforming the cover, an operating temperature is calibrated for a heat- responsive switch.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hermetic compressor for a refrigerating machine and a heat-actuated switch suitable for protecting an electric motor used in this kind from overheat and burnout.

[0002]

2. Description of the Related Art A motor used in, for example, a hermetic compressor for a refrigerator is normally operated by surrounding a refrigerant and a lubricating oil around the motor in a hermetically sealed housing.
Moreover, it must be taken into consideration that the pressure in the closed housing fluctuates in a very wide range in consideration of the maximum values of the low pressure state and the high pressure state during non-operation or operation. In order to operate the motor accurately in such a manner that it is used in such an atmosphere and is sensitive to changes in the temperature and current of the winding of the motor to open the electric circuit in the event of an abnormality and stop the operation of the motor. In such an environment, it is made an airtight container to prevent invasion of refrigerant etc. into the contact part of the switch.
The container must have sufficient pressure resistance, have the characteristics of distinguishing heat sensitivity and abnormal current from normal current, and must be small and have a large switching capacity and excellent durability. It has become particularly difficult to provide a heat-actuated switch which meets the conditions, ensures stable manufacturing quality, and is inexpensive.

[0003]

Conventionally, as a thermal response switch of this type, "thermal response switch" and "motor protection" described in Japanese Patent Publication No. 58-56213 and Japanese Patent Publication No. 62-6294 are disclosed. In the "device", the sealed container of the heat-responsive switch has sufficient pressure resistance so that the operating characteristics of the sealed container of the heat-responsive switch are not affected by severe temperature and pressure changes in the sealed housing containing the compressor including the motor as described above. However, there is a drawback in that the thickness of the closed container of the switch including the heat responsive plate made of the bimetal or the like having the movable contact and the fixed contact engaging with this must be extremely increased. . Further, since the relative positions of the movable contact and the fixed contact are associated with each other when the case of the switch is finally sealed as a closed switch, the confirmation must be done after sealing by means such as X-ray. It has the disadvantage that it cannot be done easily. Furthermore, the switch repeats the operation of interrupting the energization in response to an abnormal current flowing through the motor or an abnormal temperature and allowing the energization again when the temperature returns to a safe temperature. The contact surface melts and scatters due to the heat generated by the arc between the contacts, and the minute scattered particles of the contact material adhere to the surface of the electrical insulator, gradually increasing the electrical insulation distance between the movable contact and the fixed contact. It is one of the main reasons that the life is determined by the contraction and weakening of the dielectric strength. One solution is to increase the electrical insulation distance, but this may lead to an increase in the size of the switch, and it requires special heat resistance such that the insulator itself is not destroyed by the heat of the arc. There's a problem. The present invention overcomes these problems, is easy to manufacture in a small size, can precisely calibrate the operating temperature of the heat responsive plate, and provides a stable heat responsive switch with a long life and at a low cost. is there.

[0004]

According to the heat-responsive switch of the present invention, a cover constituting one side of a container has a substantially arc-shaped portion at its intermediate portion and both ends thereof are close to a spherical surface by pressing a metal plate. The molded long dome shape is formed into a shape with excellent pressure resistance, and the other is a header plate formed by punching out a metal plate into a flat shape that includes at least the opening end face to be welded to the opening end face to form a closed container. Composed. A through hole is provided in the header plate on one side in the longitudinal direction, and an electric conductor is fixed to the through hole by an electrically insulative filler such as glass. Both ends of the electric conductor are inside and outside the airtight container. It projects to the side for a predetermined length. A fixed contact is provided on the other side of the header plate on the inner side of the airtight container.

The heat-responsive plate support made of metal has one end fixed along the longitudinal direction of the header plate to the protrusion of the conductor inside the airtight container by a method such as welding and the other end made of a heat-resistant material such as ceramic. Having a calibrating piece made of electrically insulating material, and the thermal responsive plate supporting portion provided between the position of the calibrating piece of the thermal responsive plate support and the position fixed to the conductor. Is a metal plate that is deformed by temperature changes such as bimetal, but has one end of a heat-responsive plate that snaps the bending direction at different temperatures by drawing a center plate into a shallow dish shape. The movable contact made of a contact material such as silver or silver alloy is fixed to the other end of the heat responsive plate, that is, the side whose position is changed when the snap conversion operation is performed. Arranged to contact To have. Then, after the header plate and the long dome-shaped cover are airtightly fixed at the opening end face by a method such as welding, the calibration piece comes into contact with the inner surface of the cover, and the other end of the heat responsive plate support is attached to the calibration piece. By displacing the cover through deformation through the cover, the contact pressure between the movable contact and the fixed contact can be adjusted according to the principle of the boom, so that the movable contact opens from the fixed contact. Is a heat-actuated switch characterized by being able to perform precisely.

By the above-mentioned constitution means, the fixed contact and the movable contact are assembled and arranged on the header plate before the final step of forming the closed container, and the mutual positional relationship can be easily confirmed. Further, the electrical insulating portion is provided on one side in the longitudinal direction of the header plate, and the fixed contact portion is provided on the other side, which makes the operating life of the switch advantageous. That is, there is no concern that the electrical insulation distance will be shortened by the fine contact material scattered from the contact due to the heat of the arc generated by opening and closing the contact, and the fixed contact is mounted on the header plate with a large heat capacity with good heat conduction. This is because the fixed contact whose temperature has risen due to the heat generated when the contact sparks is quickly cooled. The cover is easy to make because it has a wide open end and is relatively shallow. The open end of this cover is brought into contact with the vicinity of the periphery of the header plate to hermetically fix them by a method such as welding, and then fixed to the conductor of the heat responsive plate support through a calibration piece that comes into contact with the inner surface of the cover. By applying a force to the other end of the heat-responsive plate, the heat-responsive plate support is deformed from the vicinity of the root of the one end where it is fixed. The amount is smaller than the movement amount of the calibration piece due to the deformation amount of the cover. Therefore, the operating pressure can be precisely calibrated by gradually adjusting the contact pressure of the movable contact with respect to the fixed contact.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3, a cover 1 made by drawing a rolled steel plate by press working is a long dome-shaped shallow container having an open end surface 1A. The intermediate portion 1B has at least a substantially arcuate portion as shown in FIG. 3, and both end portions 1C thereof are formed into a shape close to a sphere. A header plate 2 formed by punching out a thicker steel plate than the cover 1 is airtightly fixed to the opening end face of the cover 1 by a method called ring projection welding in the process of sealing the switch. Header plate 2
1 has a through hole 2A on one side in the longitudinal direction thereof, that is, on the left side in FIG. 1, and at the center of this through hole 2A, a conductor 3 is an electrically insulating filler such as glass, ceramics or synthetic resin. It is fixed by 4.

For example, when the filler 4 is glass, it is appropriate to use an alloy of nickel and iron for the material of the conductor 3 so as to form a compression type seal in consideration of the thermal expansion coefficient of the header plate and the glass. is there. As shown in FIG. 1, the conductor 3 penetrates the through hole 2A of the header plate 2 and is shown in FIG. The left end is fixed conductively by welding.

The heat responsive plate support 5 has a planar shape as shown in FIG. 2, and has six small welding projections 5A1 to 5A6 formed on the fixed end 5A at the left end in the figure and the end face of the conductor 3. Can be fixed easily and surely. In addition, as shown in FIG.
A small hole 5B for positioning is formed. Further, a support portion 5C is formed by cutting and bending from the vicinity of the central portion of the heat responsive plate support 5 toward the fixed end 5A side, and, for example, six welding projections 5C1 to 5C1 are provided near the left end of the support portion 5C. 5C6 is formed. Further, as will be described later, holes 5D are formed in the support portion 5C as needed to facilitate the assembly and to improve the characteristics.
In addition, it is preferable to provide ribs 5F for increasing the strength in the longitudinal direction of the heat responsive plate support 5 as can be seen by referring to FIG. 3 as a whole.

An electrically insulative calibration piece 6 such as a ceramic has a portion inserted into the small hole 5B of the heat responsive plate support 5 and a diameter larger than this portion, and the upper end surface is spherical, as can be seen clearly in FIG. It has a shape consisting of Of course, the shape of the calibration piece 6 is not limited to this embodiment, and it is easy to use the function of electrically displacing the displacement force received from the cover 1 to the right end portion of the heat responsive plate support 5 as its function. Is understood by.

A left end 7A of the heat responsive plate 7 is formed by punching out a metal plate such as bimetal or trimetal which is displaced by a change in temperature into a substantially rectangular shape, and drawing a substantially central portion 7B into a shallow dish shape so as to perform a snap movement. Is the six projections 5C provided on the support portion 5C of the heat responsive plate support 5.
It is fixed by welding with 1 to 5C6. A movable contact 8 having a contact surface made of silver or a silver alloy is fixed to the right end 7C of the heat responsive plate 7 by welding. Moving contact 8
The fixed contact 9 for contacting with or separating from is fixed to the other longitudinal direction of the header plate 2, that is, the right side in the figure by a method such as welding.

In the assembly of the thermoresponsive switch of this embodiment, the conductor 3 is fixed to the center of the through hole 2A of the header plate 2 by the filling material 4, and then the fixed contact 9 is fixed to a predetermined position of the header plate.
The fixed side end of the heat responsive plate 7 having the movable contact 8 fixed thereto is fixed to the supporting portion 5C of the heat responsive plate support 5. Next, the fixed end 5A of the heat responsive plate support 5 is fixed to the conductor 3. In this state, the calibration piece 6 is inserted into the small hole 5B formed in the vicinity of the free end of the heat responsive plate support 5 so that the movable contact and the fixed contact are almost lightly contacted or face each other with a very small gap. Check if it is installed. As can be seen in FIG. 4, which is an enlarged view of a part of FIG. 1, the distance D from the upper surface of the thermal response plate 7 to which the movable contact 8 is attached to the lower end surface of the calibration piece.
Check that is within the specified dimensional tolerances. Distance D
Is large, the arc generated when the contacts are opened and closed is large,
It's also not good to be too small. This distance D is slightly reduced by the operation temperature calibration work described later, but it is necessary to consider this in advance. Further, when the cover 1 is welded to the header plate, in consideration of the shallowness of the cover due to welding, check whether the inner surface has a slight gap with the upper end surface of the calibration piece 6 or has a size that makes a light contact. To do. If these conditions are satisfied, the cover 1 is hermetically welded and fixed to the header plate 2.

When the above-mentioned conditions are not satisfied, the portion 5E having a narrow width in the vicinity of the fixed end 5A of the heat responsive plate support 5 and the root part of the support 5C are deformed to adjust the conditions and then the cover is formed. 1 is hermetically welded and fixed to the header plate 2. In this case, making a 5D hole near the root part facilitates the bending work.

When the airtight container is completed, as shown in FIG. 4, jigs G1 and G2 for sandwiching the header plate 2 and the cover 1 are used to move the heat responsive plate 7 to the dotted line in FIG. 1 at a predetermined operating temperature. Cover 1 so that its bending direction is reversed
Are recessed as shown by the dotted line in FIG. This causes downward bending deformation of the narrow portion 5E near the fixed end of the heat responsive plate support 5 through the calibration piece 6, and the heat responsive plate 7 is displaced clockwise in FIG. give. As a result, the contact pressure between the movable contact 8 and the fixed contact 9 is increased to eliminate chattering when the movable contact 8 is separated from the fixed contact by snapping over the thermoresponsive plate at a predetermined operating temperature. With it, it can be calibrated to a predetermined operating temperature.

In the heat-responsive switch constructed as described above, in an atmosphere of a predetermined temperature, for example, 150 ° C., the heat-responsive plate suddenly reverses as shown by the dotted line in FIG. When the temperature reaches 80 ° C, it jumps back to the state shown by the solid line and the contacts are automatically closed again. 1 to 3
As shown in, the lead wires indicated by reference numerals 10 and 11 are fixed by welding or the like, and connected in series to a circuit that supplies current to the electric motor. Although an excessive current flows at the time of start-up, when the normal start-up is completed and the operation state is entered, the current reaches the rated value, so the temperature of the heat-responsive plate does not rise to the predetermined operating temperature and the heat-responsive switch does not operate. The current flowing through the thermal switch of this embodiment is the lead wire 10-conductor 3-thermodynamic plate support 5-thermodynamic plate 7-movable contact 8-fixed contact 9-header plate 2-lead wire 11
However, when the heat generated by the resistance of this circuit causes the heat responsive plate 7 to reach a predetermined temperature, for example, 150 ° C., it becomes an inverted position as shown by the dotted line in FIG. 1 and the supply current to the electric motor is cut off. At this time, an arc is generated between the movable contact and the fixed contact, and a part of the movable contact and the fixed contact are melted by Joule heat and arc heat to cause a slight loss. The fine particles of the loss are scattered from between the contacts, and when they reach the surface of the filling material 4 which insulates the contacts of the switch, the deterioration of insulation is gradually advanced to reach the end of life. However, in the present invention, the distance between the contact portion 5 and the filling material 4 can be set sufficiently in the longitudinal direction of the switch, which is very advantageous for insulation deterioration. Further, the heat received by the fixed contact is conducted to the header plate having a large heat capacity to rapidly lower the temperature, which is advantageous in preventing the fixed contact from being worn.

Further, the heat received by the movable contact is absorbed by the heat responsive plate, and there is an effect that the temperature of the heat responsive plate is not lowered within a certain period of time after the current stops flowing, and the temperature at which it automatically recovers, for example, Extend the off time to reach 80 ° C. This has the advantage of prolonging the life of such thermally actuated switches that repeat automatically. Of course, it is also advantageous as an effect of suppressing the temperature rise of the electric motor to be protected. In addition, the hole formed in the support portion 5C provided in the heat responsive plate support 5
When the temperature of the heat responsive plate is dissipated from the heat responsive plate support 5 via the conductor 3 by 5D, the portion where the hole 5D is formed has a high temperature due to the increased electrical resistance. It is advantageous in that the temperature of the heat responsive plate is less likely to escape due to the synergistic effect of the fact that the heat conduction cross-sectional area is narrowed, and the time until the temperature returns after operation is maintained for a long time.

[0017]

As described above, according to the present invention, since the fixed contact and the movable contact are assembled and arranged on the header plate before the final step of forming the hermetic container, mutual positional relationship can be confirmed. You can easily. And the constructed closed container has very high pressure resistance, and since the distance between the contact and the electrical insulating material can be set large, minute scattering of contact material generated by heat such as arc It has an effect of hardly adhering to the surface of the electrically insulating filler.

Further, the heat received by the movable contact is absorbed by the heat responsive plate, and there is an effect that the temperature of the heat responsive plate is not lowered within a certain period from the time when the current stops flowing, and the temperature at which the heat is automatically restored is reached. Extend the off time until. Further, when the temperature of the heat responsive plate is dissipated from the heat responsive plate support through the conductor by the hole formed in the support portion provided in the heat responsive plate support, the holed portion is Due to the synergistic effect of the high temperature spot part due to the increased electric resistance and the narrowed heat conduction cross-sectional area, the temperature of the heat responsive plate becomes difficult to escape and the time until it returns after operation is reduced. It is advantageous in that it is held for a long time. These things have the advantage of prolonging the life of this type of thermally actuated switch that repeats automatically. Further, the heat received by the fixed contact is conducted to the header plate having a large heat capacity to rapidly lower the temperature, which is advantageous in preventing the fixed contact from being worn.

Further, in calibrating the operating temperature, a force is applied to the other end of the heat responsive plate support, which is not fixed to the conductor, through a calibration piece that comes into contact with the inner surface of the cover after forming a closed container with the cover and the header plate. As a result, the heat-responsive plate support is deformed from the vicinity of the root of the one end where it is fixed, so the movement amount of the heat-responsive plate support part to which the heat-responsive plate is fixed by the principle of the lever is the deformation of the cover. Less than the amount of movement of the calibration strip due to the amount. Therefore, the operating pressure can be precisely calibrated by gradually adjusting the contact pressure of the movable contact with respect to the fixed contact.
As described above, according to the present invention, it is easy to manufacture in a small size, the operating temperature of the heat responsive plate can be precisely calibrated, and a stable heat responsive switch with a long life can be provided at low cost.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of a thermoresponsive switch of the present invention.

[FIG. 2] A in which only the cover of the thermal switch of FIG. 1 is cut off
-A cross-section arrow view

[FIG. 3] B in which only the cover of the thermal switch of FIG. 1 is cut
-B cross-section arrow view

FIG. 4 is a partially enlarged view of FIG.

[Explanation of symbols]

1: Cover 2: Header plate 3: Conductor 4: Filling material 5: Thermal plate support 6: Calibration piece 7: Thermal response plate 8: Moving contact 9: Fixed contact

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Isao Touhou             178, Kita, Kasumigaoka-cho, Owariasahi-shi, Aichi (72) Inventor Hideki Ozeki             2 of 40, Minamiyamana, Oyamanishi, Fuso-cho, Niwa-gun, Aichi

Claims (3)

[Claims] 1. A long dome-shaped cover made of metal, which has a substantially arcuate portion in the middle and has both ends close to a spherical surface,
A header plate that is welded to the open end face to form a closed container, and the header plate is a metal plate whose planar shape at least includes the end face shape of the long dome-shaped cover, and is transparent in one of its longitudinal directions. A hole is provided in the through hole, and a conductor is penetrated through the header plate by an electrically insulative filler such as glass, and protrudes a predetermined length in the upper surface direction and the lower surface direction, and is hermetically fixed. One end of a heat-responsive plate support made of metal is fixed to the conductor protruding toward the inner side of the closed container constituted by the header plate and the cover along the longitudinal direction, and the other end of the heat-responsive plate support is provided. A calibration piece formed of an electrically insulating material having heat resistance is inserted between the cover and the vicinity, and the heat responsive plate support is closer to the fixing portion with the conductor than the calibration piece insertion position. Supporting part of the heat-responsive plate It is made of a material that deforms in response to changes in temperature, such as bimetal, and has a rectangular shape at its center. One end of the heat responsive plate that changes the temperature is fixed, and the other end of the heat responsive plate, that is, the end that moves during snap movement, is provided with a movable contact made of an electrical contact material such as silver or silver alloy, and the movable contact is movable. The contact is arranged so as to come into contact with or separate from a fixed contact fixed to the other longitudinal direction of the header plate, and the cover is deformed by an external force to be inserted between the other end of the heat responsive plate support and the cover. As a result of displacing the heat responsive plate support near the fixed part with the conductor through the attached calibration piece, it is possible to precisely adjust the contact pressure between the movable contact and the fixed contact, and at a given temperature. Fixed movable contact Thermo-switch to calibrate the operating temperature of the separable from point is equal to or reliably and easily. 2. A long dome-shaped cover made of metal, which has a substantially arcuate portion in the middle and has both ends close to a spherical surface,
A header plate that is welded to the open end face to form a closed container, and the header plate is a metal plate that is thicker than the cover, and has a shape that at least includes the end face shape of the long dome-shaped cover. A through hole is provided on one side of the longitudinal direction, and a conductor penetrates the header plate by an electrically insulative filling material such as glass, and protrudes by a predetermined length in the upper surface and the lower surface direction, respectively. A heat-sensitive plate support made of metal is fixed at one end along the longitudinal direction to the conductor protruding toward the inside of the closed container constituted by the header plate and the cover, In the vicinity of the other end of the heat responsive plate support, a calibration piece formed of a heat resistant electric insulating material is inserted and attached between the cover and the cover.
Further, the heat responsive plate support is provided with a support portion of the heat responsive plate at a portion closer to the fixing portion with the conductor than the calibration piece insertion position, and the cross-sectional area is narrowed near the support portion to reduce heat. Has a portion where it is difficult for the conduction of heat to occur and heat is easily generated, and the supporting portion is made of a material that deforms according to temperature changes such as bimetal in a substantially rectangular shape and its center is drawn into a shallow dish shape. Due to this, one end of the heat responsive plate that changes the bending direction in a snap manner according to different temperatures is fixed, and the other end of the heat responsive plate, that is, the end that moves during snap movement, is made of an electrical contact material such as silver or silver alloy. A movable contact is provided, and a fixed contact is firmly fixed to the other longitudinal direction of the header plate so as to quickly transfer the heat received when the switch is opened and closed to the header plate, and the fixed contact is the movable contact. Contact with or separate from The cover is deformed by an external force, and is fixed to the conductor of the heat responsive plate support through a calibration piece inserted between the other end of the heat responsive plate support and the cover. As a result of the displacement in the vicinity of the contact point, it is possible to precisely adjust the contact pressure between the movable contact and the fixed contact, and the operating temperature at which the movable contact separates from the fixed contact at a given temperature can be calibrated reliably and easily. A thermo-responsive switch characterized in that 3. A long dome-shaped cover made of metal, which has a substantially arcuate portion in the middle and has both ends close to a spherical surface,
A header plate made of a metal plate having a planar shape that includes at least the end surface shape of the long dome-shaped cover to be welded to the opening end surface, and a through hole is provided in one of the longitudinal directions of the header plate. Is an electrically insulative filler such as glass, which penetrates the header plate by a predetermined length in the direction of the upper surface and the lower surface of the conductor to hermetically fix it, and fixes it in a fixed position at the other position in the longitudinal direction. It is made of a material such as bimetal in a strip shape, and its center is drawn into a shallow dish. The bending direction is changed when snapping according to different temperatures. The reaction plate and the other end of the heat reaction plate are fixed to the support portion of the heat reaction plate disposed near the center of the metal heat reaction plate support, and the end of the heat reaction plate support moves with the fixed contact. The plane position of the contact is Step of fixing to the conductor so as to be cut, step of attaching a calibration piece near the free end of the heat responsive plate support, and the movable contact and the fixed contact are in contact with each other or at a spacing position within a predetermined dimension. After the step of performing the steps, and then the step of confirming or adjusting that the distance between the heat responsive plate and the calibration piece is within the predetermined dimensional tolerance, the cover is hermetically welded and fixed to the header plate to form the closed container. Then, a method of manufacturing a heat-responsive switch for calibrating an operating temperature including a step of deforming a cover.