KR100298425B1 - Thermal switch - Google Patents

Abstract

The thermosensitive switch (1) is a sealed container by a cylindrical metal container (3) having a metal cover plate in which an electrically conductive terminal is insulated and securely sealed, and a bottom surface welded to an open end terminal near the outer circumference of the cover plate. Make up.

Inside the hermetically sealed container, a disk-shaped thermally active plate 9 formed in a shallow dish shape is accommodated, and has a contact mechanism for opening and closing the fixed contact portion and the movable contact by the operation of the thermally active plate 9.

The metal container 3 of the thermosensitive switch 1 has the thickness t, the length L, and the diameter D of the cylindrical portion, where t / L = 1/60 to 1/120, L The heat conduction from the container bottom 3B to the thermally active plate and the heat conduction through the cylindrical portion in the lid plate direction are defined, respectively, so as to be in a relationship of 0.5D.

For this reason, the temperature rise of the bottom face 3B of the container can be accelerated | stimulated, and the heat response speed as a switch can be made quick, by suppressing the transfer rate of the heat | fever which should heat the heat-activated board 9 to the lid board direction.

Description

Thermal Switch {THERMAL SWITCH}

The present invention relates to a thermally sensitive switch using a thermally active plate, for example, in an automobile or the like, a part that is overheated in the event of an equipment abnormality such as a compressor for circulating a refrigerant in a heat exchange system system, an engine, an electric motor, and the like. It relates to a thermosensitive switch that detects the temperature and protects the instrument from damage due to overheating.

Conventionally, a thermosensitive switch that opens and closes an electric circuit using a deformation such as bimetal has been used as this type of switch.

The thermosensitive switch 101 shown in FIG. 7 has a cylindrical disc 103 with a bottom plate-shaped lid plate 102 made of metal, and hermetically seals the open end of the container 103 near the outer circumference of the lid plate 102. Consists of a sealed container fixed by

The reason why the sealed container is adopted is to prevent the intrusion of moisture and the like into the inside of the container and to stabilize the gas composition enclosed inside the container for a long time for the reasons described later.

As a material of the container 103, a steel plate is used for the reason that weldability is favorable.

The cover plate 102 is provided with through holes 102A and 102B, each of which has a conductive pin 104A and 104B made of metal and electrically sealed with an electrically insulating filling material 105 such as glass. Is fixed.

On the other hand, in the vicinity of the lower end of the conductive pin 104A, a fixed conductive member 106 having a thick (co) shape is fixed to the upper end thereof by welding or the like.

In the vicinity of the lower end of the conductive pin 104B, an elastic movable contact member 107 is fixed to the fixed terminal 107A in the same manner as welding.

The movable contact 108 is fixed to the tip 107B of the movable contact member 107 and is arranged to contact the contact portion 106A of the fixed contact member 106.

At the bottom of the container 103, a thermally actuated plate 109 formed by punching a bimetal-like material into a circular shape and formed into a shallow dish is disposed, and a holding plate 110 made of a spring material is disposed thereon.

Again, a pressure receiving member 111 made of a heat resistant insulating material is disposed on the holding plate 110, and the tip of the pressure receiving member is press-fitted into the hole 107C formed in the movable contact member 107. Is fixed.

The operation of the thermally sensitive switch 101 will be described. In the normal temperature state, the thermally actuated plate 109 is in a curved state expanded downward as shown in FIG. 7, and rapidly reverses when the temperature rises to a predetermined temperature. Since the curved direction is set in advance so that the center thereof is inflated upward, this center portion pushes up the pressure receiving member 111.

The pressure receiving member 111 pushes the movable contact member 107 to separate the movable contact 108 at its tip from the contact portion 106A of the fixed contact member 106 to block the converter.

Next, a partial cross-sectional view shown in FIG. 8 and an enlarged view of the portion shown in FIG. 8 will be described as an example of the case where the thermosensitive switch is attached to the control target device when attached to the control target device.

Here, the attachment part A1 is provided in advance in the housing A of the compressor for automobile air conditioners.

This attachment portion is a through hole formed in the discharge refrigerant passage A2 of the compressor, and is placed at a position where the attached thermosensitive switch 101 can quickly detect the temperature of the refrigerant to be detected.

Lead wires 112A and 112B are electrically connected to the conductive pins 104A and 104B of the thermally sensitive switch 101 to which they are attached. In order to protect against external force or vibration applied at the time, the protective cap 113 is covered with the thermally sensitive switch 101, and an insulating filling material 114 is filled in the cap.

A thermally sensitive switch 101 is inserted into the attachment portion A1 together with an O-ring 115 made of silicone rubber or the like, and the upper surface of the protective cap 113 is inserted into an arc-shaped elastic member such as a snap ring. It is held at 116 and fixed to seal the attachment part by a switch.

This thermally sensitive switch 101 realizes high thermal response performance by placing the thermally active plate 109 on the bottom surface of the container 103.

In addition, the heat sensitive switch is required to be smaller due to problems in the mounting position.

However, when attached to the housing of the compressor for an automotive air conditioner, which is always exposed to the outside air as in the above-described example, the compressor housing surface is deprived of heat by the outside air, and again, the heat of the thermosensitive switch directly attached thereto. Since heat is deodorized by heat conduction through the housing, there is a case that the thermal response to the sudden rise in temperature of the refrigerant is not sufficiently obtained, especially when the outside air temperature is low.

In addition, since the lid plate 102 needs a thickness to hold the conductive pins 104A and 104B, the heat capacity of the lid plate 102 is increased so that the heat received from the tip of the vessel passes through the cylindrical portion of the vessel. There was also a problem that the temperature rise rate of the thermally actuated plate 109 was lowered and the response as the thermally sensitive switch was deteriorated because it was deodorized.

In particular, by miniaturizing the container, the length of the container cylinder was shortened, and heat was easily deodorized to the lid plate side.

In addition, in order to increase the response speed, for example, as shown in FIG. 10, the thermally sensitive switch 101 is fixed to the tip of the conductive pin 122A of the hermetic terminal 122 electrically connecting the inside and the outside of the compressor 121. The method is valid.

In this way, the thermally sensitive switch can be placed inside the inner wall of the compressor housing only with a conductive pin to minimize the heat conduction from the switch to the outside of the compressor, and at the same time, the heat response can be improved by allowing the entire switch to flow in the heat medium refrigerant. .

Substitute tests using oil instead of heating medium confirm that the time required for operation is less than about half, and the same results are obtained in actual use.

However, this method has a problem that the housing of the compressor is enlarged, the number of parts is increased, and the cost is high because the width of the refrigerant passage must be wide enough to accommodate the heat sensitive switch.

In addition, as described above, if the heat capacity of the lid plate is high, there is a problem that the temperature rise rate of the thermally active plate is lowered.

Therefore, there is a need for a thermally sensitive switch capable of improving thermal response without increasing the size of the compressor housing or increasing the number of parts as compared with the conventional art.

1 is a cross-sectional view of an embodiment of a thermal switch according to the present invention

2 is a cross-sectional view showing an operating state of the thermal switch of FIG.

3 is a cross-sectional view taken along the line A-A of FIG.

4 is a partial cross-sectional view showing a state in which the thermal switch of Figure 1 is attached to the control target device;

5 is an enlarged partial view of FIG. 4.

6 is a plan view of the holding plate used in the thermal switch of FIG.

7 is a cross-sectional view of an example of a thermally sensitive switch in the related art.

FIG. 8 is a partial cross-sectional view showing a state in which the thermal switch of FIG. 7 is attached to a control target device;

9 is an enlarged partial view of FIG. 8.

10 is a partial sectional view showing a state in which a conventional thermally sensitive switch is attached to a control target device;

(Explanation of symbols on the main parts of drawing

1. Thermal switch

2. cover plate

2A. Staircase

2B, 2C. Through hole

3. Container

3C. Cylinder

4A, 4B. Challenge pin

5. Filling material

6. Fixed contact member

6A. Fixed contact point

7. Movable contact member

8. Movable Contact

9. Thermal Response Plate

10. Retaining Plate

11. Pressure receiving member

12A, 12B. Lead wire

13. Protective cap

14. Filling material

15.O-ring

16. Elastic member

Here, in the thermosensitive switch of the present invention, a metal plate-shaped cover plate and two through-holes are drilled in the cover plate to hold the first and second terminals made of an electrically insulating filling material, respectively, in those holes. A metal container comprising a cylindrical portion having an open end terminal in close proximity to the outer circumference of a lid plate and a bottom portion of a shallow dish shape, wherein the open plate terminal is welded to the lid plate to form an airtight container. According to the inner bottom, a sudden inverted operation is performed at a predetermined first temperature, and a disc-shaped heat-activated plate formed in a shallow dish shape is accommodated so as to rapidly return to a second temperature, and a retaining plate having elasticity is disposed opposite the heat-sensitive plate. The fixed contact member is welded to the first terminal and the movable contact member is welded to the second terminal, and the pressure receiving member is disposed on the movable contact member to replace the thermally active plate. The other terminal is jig when the fixed contact member and the movable contact member are arranged in the same direction to each of the above two terminals and on the extension line including the center and the welding point of each terminal. In a thermosensitive switch having a welded portion welded so as not to interfere with the arrangement of the metal, the metal container has its thickness set at 1/60 to 1/20 of the diameter of the cylindrical portion, and the length of the cylindrical portion is set at least 0.5 times the diameter. Therefore, the thermal conductivity of the thermally active plate through the bottom of the container and the thermal conductivity through the cylindrical portion from the bottom of the container to the lid plate direction are respectively defined, and the temperature rise rate of the thermally active plate is adjusted.

With this configuration, the heat of the metal base of the heat sensitive switch is difficult to transfer from the cylinder portion of the vessel to the housing of the compressor, and in the case where the temperature of the refrigerant rises rapidly, the heat transfer plate can be effectively heated while suppressing the heat escape. In addition, the response speed as the thermal switch can be increased.

Another feature is that the metal container consists of a metal with at least one-half the thermal conductivity of iron, for example iron-chromium alloys, iron-nickel alloys, stainless steels, and the like.

With this configuration, even if the shape of the metal container of the thermosensitive switch is the same as that of the conventional product, the heat of the bottom of the container becomes difficult to be transferred from the cylindrical part of the container to the housing of the compressor, and again correlates the thickness and length of the cylindrical part of the container. By setting, it is possible to increase the effect of quickly transferring heat from the bottom of the vessel to the thermally actuated plate, and to increase the response speed as the thermally sensitive switch.

In addition, by selecting the container in this way, it is possible to greatly improve the thermal response by simply increasing the size of the switch itself to be the same or slightly, so that it is hardly necessary to change the conventional attachment position, and the housing of the compressor is not required to be enlarged.

Another feature is that the enclosed gas containing 50-95% helium in the sealed container is sealed at a pressure higher than atmospheric pressure, so that the heat of the vessel can be quickly transferred to the thermally active plate, especially at a sudden temperature rise.

In addition, since the enclosed gas is higher than atmospheric pressure, external gas hardly penetrates into the container, and the composition of the enclosed gas can be stabilized for a long time.

Another feature is to form a step in the vicinity of the circumference of the lid plate to assemble the inner circumferential surface near the open end terminal of the container so as to almost contact the outer circumference of the step of the lid plate.

In the present invention, even when so-called scattering occurs when welding the lid plate and the container in this invention, it is possible to prevent the intrusion inside the container by the stepped portion, and at the same time, the position of the lid plate and the container during assembly is assured. Become easy.

Another feature is that the lead wires are fixed by welding at the first and second terminals, respectively.

Therefore, it can be used even in a high temperature environment rather than fixing by soldering.

(Example)

Next, the thermal switch will be described with reference to FIGS. 1 to 5.

1 is a cross-sectional view showing an embodiment of the thermal switch of the present invention, Figure 2 is a cross-sectional view showing the operating state, Figure 3 is a horizontal cross-sectional view of Figure 1, Figure 4 is a thermal control switch of the control target device 1 A partial cross-sectional view showing a state of being attached to a compressor for a vehicle air conditioner, which is an example, and FIG. 5 is a partially enlarged view thereof.

This thermally sensitive switch (1) has a disk-shaped lid plate (2) and a metallic cylindrical container (3) with a bottom surface, and is provided in the opening end of the container (3) at the circumferential edge of the lid plate (2). The branch 3A is hermetically fixed by ring projection welding or the like to form a sealed container.

The container 3 is formed by tightening a metal plate into a cylindrical shape with a bottom surface by press working or the like. In this embodiment, the length L of the cylindrical portion 3C of the container 3 is set longer than that of the conventional one. The ten gradients of are supposed to be gentle.

Moreover, in order to have high pressure resistance performance, the bottom surface 3B of a container is made into the spherical shallow dish shape as shown, for example in FIG.

In the present invention, attention has been paid to the movement of heat through the vessel of the thermosensitive switch, and the relationship between the thermal conductivity of the vessel and the length and thickness of the vessel cylindrical portion with respect to the operation time of the thermosensitive switch has been obtained.

As a result, when the thermal conductivity of the thermosensitive switch container is low, the heat applied to the bottom of the container is difficult to move to the outside, and when the thickness of the container cylinder is thin, the cross-sectional area is small, so heat is also difficult to transfer, and when the length of the cylinder is long, the thermal gradient is gentle. The heat also becomes difficult to move.

In this embodiment, the length L is made longer than that of the prior art without changing the thickness t of the container, so that the thermal gradient at both ends of the container cylindrical portion is smoothed to suppress the movement of heat from the bottom of the cylinder.

The cover plate 2 is provided with first and second through holes 2B and 2C, and the through holes are made of metal conductive pins 4A and (1) which are the first and second terminals of the thermally sensitive switch, respectively. 4B) is hermetically fixed by an electrically insulating filling material 5 such as glass.

In the vicinity of the lower end of one conductive pin 4A, a conductive fixed contact member 6 having a high thickness is fixed by welding such an upper end.

At the distal end of the fixed contact member 6, a fixed contact portion 6A made of silver alloy or the like is formed.

In the vicinity of the lower end of the conductive pin 4B, a movable contact member 7 made of copper alloy having sufficient elasticity, such as beryllium copper, is fixed in the same manner as for welding the fixed terminal 7A.

A movable contact 8 such as a silver alloy is fixed to the front end 7B of the movable contact member 7 and disposed so as to contact the fixed contact portion 6A of the fixed contact member 6.

In this case, the fixed contact member 6 and the movable contact member 7 are the same as shown in Fig. 3 for the conductive pins 4A and 4B to which the weld portions 6B and 7B are welded, respectively. Direction, and the welding position is relative to the electrodes E1 to E4, which are welding jig, on the extension lines W1 and W2 connecting the center of each conductive pin and the welding point as shown in the drawing. It is a position which does not interfere with a conductive pin, and mutual conductive pin is a position which does not interfere with the welding of each contact member.

This facilitates assembly work and facilitates welding automation.

Again, the welding teeth and the welding electrode can be made into a shape that is unreasonable with respect to the pressurizing direction, so that the service life is improved and the burden of maintenance work is reduced.

In addition, the narrow space between the conductive pins makes it possible to manufacture a small thermally sensitive switch.

The bottom portion 3B of the container 3 is arranged with a thermally actuated plate 9 formed in a shallow dish shape so as to punch a bimetal-like material in a circular shape to invert and return the curved direction at a predetermined temperature. The holding plate 10 produced by the is arrange | positioned.

Again, on the holding plate 10, a pressure receiving member 11 made of a heat resistant insulating material such as ceramics is disposed, and the tip 11A of the pressure receiving member is perforated in the center of the movable contact member 7 described above. It is fixed to the hole 7C by the method of press fitting.

The retaining plate 10 has a plurality of slender legs 10A extending radially from the center as shown in FIG. 6, and in the embodiment there are four, and the legs 10A are bent at a predetermined angle, respectively, to have an approximately umbrella shape. It is produced with elastic plates, such as formed thin phosphor bronze and beryllium copper.

The holding plate 10 is always positioned by pushing the thermally actuated plate 9 in the direction of the container bottom portion 3B with a force that is substantially unaffected by its operation.

A through hole 10B is drilled in the center of the holding plate 10, and the lower end 11B of the pressure receiving member 11 is inserted through the through hole 10B so as to project slightly from here.

For this reason, the positioning of the pressure receiving member 11 can be made easy, and the deformation | transformation of the holding plate 10 by the repetition of the inversion return operation | movement of the thermally active board 9 can be prevented as mentioned later.

Again, the holding plate 10 is a thin plate, and the leg portion 10A is thin, and the contact with the thermal actuating plate 9 is made only at the tip of the leg, so that the heat of the thermal actuating plate 9 passes through the holding plate to receive the pressure. It is hard to be transmitted to the member 11, and contributes to suppressing heat escape through the conductive pins.

The operation of the thermosensitive element is basically the same as the conventional example described above.

As a result, in the normal temperature state, the thermally actuated plate 9 is in a curved state expanded downward as shown in FIG. 1, and suddenly reverses when the temperature rises to a predetermined first temperature in response to the temperature rise, and the center of the heat-changing direction is shown in FIG. 2. Since the shape is inflated upwards, its center portion abuts against the lower end 11B of the pressure receiving member inserted into the center of the holding plate 10 and pushes up the pressure receiving member 11.

The pressure receiving member 11 pushes up the movable contact member 7 to disengage the movable contact 8 at its tip from the fixed contact portion 6A of the fixed contact member 6 to block the converter.

In addition, when the temperature of the thermally actuated plate 9 drops from the high temperature state to a predetermined second temperature, the thermally actuated plate 9 returns its curved direction, and the movable contact 8 is brought into contact with the fixed contact portion 6A again to conduct the conductive pin. The converter between (4A) and (4B) is turned on.

In the configuration in which the lower end 11B of the pressure receiving member 11 is inserted into the through-hole 10B of the holding plate 10 so as to project slightly from here, in the above-described protection operation, the thermally actuating plate 9 moves upward. The expanding reversal operation directly impacts the lower end 11B of the pressure receiving member 11 at one time.

As a result, the holding plate 10 is not directly hit by the heat-sensitive plate 9 so as to be sandwiched between the pressure receiving members 11, so that the holding plate 10 is deformed or stretched due to the repeated strike. Does not occur.

Next, a case in which the thermally sensitive switch 1 is attached to a compressor for a vehicle air conditioner, which is one of the control target devices, will be described as an example of the partial sectional view of FIG. 4 and FIG.

The housing A of the compressor for the vehicle air conditioner is formed with the attachment portion A1 of the thermosensitive switch in advance as in the conventional example described above.

The attachment portion is a through hole formed in the discharge refrigerant passage A2 of the housing A of the compressor, and the heat-sensitive switch 1 inserted by inserting the container 3 is directly exposed to the discharge refrigerant, which is the object to be detected. It is in a position to detect changes quickly.

The thermally sensitive switch 1 is electrically conductively fixed to the conductive pins 4A and 4B by connecting the lead wires 12A and 12B by welding. The protective cap 13 is covered with the thermally sensitive switch 1 and the insulating filler 14 is filled in the cap in order to prevent damage to the external force or vibration applied during the operation.

The thermosensitive switch thus constructed is inserted together with an O-ring 15 made of silicon rubber or the like from the outside of the compressor to the attaching portion A1, and the O-ring 15 is inserted into the inner wall of the attaching portion A1 and the container of the thermosensitive switch ( This attachment portion A1, which is a through hole, is covered with airtight while being brought into close contact between the outer wall of 3) and the flange portion of the lid plate 2.

Again, the upper surface of the protective cap 13 is held by a snap ring or the like, which is an arc-shaped elastic member 16, which is well known so as to prevent the switch from falling off.

In this way, the thermally sensitive switch 1 is held in a position outside the inner surface of the outer wall of the compressor housing A, so that only the O-ring and the elastic member can secure the airtightness and secure fixing of the attachment portion.

Here, the outer wall of the container of the thermosensitive switch 1 is not directly in contact with the inner surface of the attachment portion A1, that is, the outer wall of the housing A, so that the heat is difficult to escape, and the metal part including the lid plate 2 is directly It does not come into contact with the housing A of the compressor.

This thermally sensitive switch 1 has a longer container than the conventional one, and since the lower half of the switch container is subjected to heat in the flow path of the discharged refrigerant, it is possible to receive heat from the refrigerant to be detected more efficiently.

In the present embodiment, the movement of heat from the bottom of the vessel is suppressed by lengthening the cylindrical portion 3C of the vessel 3 of the thermosensitive switch. Or thinn the thickness t of the container 3.

However, if the length L of the cylindrical portion is too long, of course, the mounting position of the switch also requires a large space, so that the housing of the compressor can be enlarged in the control target device and the embodiment.

In addition, there is a problem that the pressure resistance performance of the switch container is reduced only by reducing the thickness t of the container in accordance with the demand of the operation speed of the switch.

In the present invention, the metal container is made of a metal having a thermal conductivity of 1/2 or less of iron, and preferably a metal having a thermal conductivity of 1/3 or less of iron, so that the heat transfer speed can be suppressed with the length and thickness of the container as it is.

Again, by setting the diameter and thickness of the container cylinder to correlate, for example, even if the thermal conductivity is greater than 1/2 of iron, the thermal conductivity of the container can be suppressed, and if the thermal conductivity is sufficiently smaller than iron, the effect is again applied. The response speed as a thermal switch can be increased.

As this container 3, the thing suitably selected from iron alloy, nickel alloy, etc. is used, for example.

In the present embodiment, the container 3 is a stainless steel plate (SUS304) is tightened and formed into a cylindrical shape with a bottom surface by press working or the like, its thermal conductivity is about 1/5 of iron at room temperature, cold rolling conventionally used About 1/4 of the steel sheet.

As such, when a container with a high electrical resistance such as stainless steel is used, there is a possibility that the difference between the electrical resistance between the lid and the container is large, and that the so-called scattering of the molten metal scatters during welding may occur. It may have an unreasonable effect on operation or insulation.

In the present invention, the step portion 2A is formed in the vicinity of the circumferential circumference of the lid plate 2, and the container 3 has an inner circumferential surface near the opening end terminal of the lid plate 2 on the outer circumference of the step portion 2A of the lid plate. It is almost in contact.

Therefore, in the case of welding of the lid plate 2 and the container 3, even if scattering occurs, it is possible to prevent intrusion into the inside of the container by the stepped portion 2A.

With such a configuration, alignment of the lid plate and the container at the time of assembly is facilitated.

In the thermally sensitive switch of the present invention, the container 3 is made of metal having less than 1/2 of iron, for example, stainless steel, whose thermal conductivity is lower than that of a conventionally used cold rolled steel sheet. The thermal response speed can be improved.

As described above, when a heat sensitive switch using a container having a relatively good thermal conductivity is attached to the housing of the compressor, the heat of the container bottom portion 3B of the heat sensitive switch is transmitted to the thermally active plate through the container and at the same time, the switch This is because the temperature rise rate of the thermally actuated plate is substantially suppressed because it moves back to the low temperature cover plate or the compressor housing via the cylindrical part of the container.

Conventionally, when attaching to the compressor, the metal parts such as the lid plate do not directly contact the metal housing of the compressor, but since the heat is transferred to the resin, which is in close contact with the switch, a quick response speed is achieved, especially when the refrigerant temperature is rapidly increased. In the case where required, the effect alone was not obtained.

In addition, since the metal cover plate constituting the airtight container uses a metal plate having a larger thickness than the container, the heat capacity is relatively large, and the heat transferred to the container moves due to the heating of the cover plate, and at the same time, the heating of the thermally active plate is delayed. It was a factor.

In addition, since the bottom of the container is made into a shallow dish in order to increase the pressure resistance performance, the distance between the thermally actuated plate and the bottom of the container is somewhat enlarged, and it is also considered that the radiant heat from the bottom of the container is difficult to reach the thermally actuated plate.

In the case where a hermetically sealed container is used for a thermally sensitive switch as in the conventional example or the present invention described above, the heat from the container is more easily transferred to the thermally actuated plate by increasing the helium ratio in the enclosed gas to be sealed in the past. This can shorten the response time, but this is not enough.

In addition, a cover plate made of a resin having a low thermal conductivity is used instead of a metal plate, or an opening is sealed with a filling material such as a resin. However, such a structure does not have substantially airtightness. It is impossible to maintain the composition stably over the long term, and long term thermal conductivity improvement cannot be expected.

Taking these points into consideration, various experiments have been carried out by focusing on the heat transfer from the bottom of the vessel of the thermosensitive switch, and it has been found that the operating time of the thermosensitive switch needs to appropriately relate the vessel diameter D to the thickness t.

As a result, with respect to the change in the diameter of the switch cylinder, the area of the thermally actuated plate housed therein changes in proportion to twice the diameter.

Therefore, when the thickness t of the container cylindrical part 3C is constant, when the diameter D of the container cylindrical part is reduced, the cross-sectional area of the outer wall of the cylindrical part relative to the unit area of the thermally active plate is relatively increased, so it is easy to avoid heat through the cylindrical part.

In addition, when the diameter of the container cylinder is increased, heat becomes difficult to escape inversely, but if the thickness is too small for the diameter, there is a problem that the pressure resistance performance is lowered.

In consideration of these points, an experiment was carried out, and it was concluded that the thickness t of the cylindrical portion should be 1/60 to 1/20 with respect to the diameter D thereof.

For example, if the thickness of the container cylinder is 1/20 or more of the diameter, the amount of heat transferred to the tip of the container is deodorized through the cylinder, such as the lid plate of the switch or the housing of the controlled device. This decreases and the responsiveness is insufficient.

In addition, when the thickness is 1/60 or less, the pressure resistance performance is lowered, so that the container 3 may be deformed by the refrigerant pressure when installed in the compressed refrigerant.

On the other hand, by making the thickness of the cylindrical part 1 / 60-1 / 20 of the diameter, the responsiveness and pressure resistance performance of a thermosensitive switch can be made compatible.

Again, if the diameter of the vessel was constant, it was found that the operating time of the thermosensitive switch was almost normally derived from the thermal conductivity of the vessel and the length and thickness of the vessel cylinder.

After all, if the thermal conductivity of the thermosensitive switch container is low, the heat applied to the bottom of the container is difficult to move to the outside, and if the thickness of the container cylinder is thin, the cross-sectional area of the outer wall of the cylinder is small, so that heat is also difficult to transfer. The longer the length of the wealth, the slower the thermal gradient, so the heat is more difficult to move.

Considering these points, the results were examined together with the experimental results, and it was found that the thermal conductivity, the shape and the operating time of the vessel of the thermally sensitive switch were almost related by the operating time index T derived from the following equation.

Operation time index: T = A · λ +

(λ: thermal conductivity, t: container cylinder part thickness, L: container cylinder part length, A and B are integers)

This operating time index T is substantially proportional to the operating time in the substitution characteristic test of the above-mentioned thermally sensitive switch if it is within a certain range of conditions.

Therefore, by comparing this value with the conventional one, the operation time can be easily estimated from the thermal conductivity and the shape of the container.

For example, in the thermosensitive switch of this embodiment and the above-described conventional example, the following relationship was derived as an empirical formula.

Estimated operation time: T1 = 32000λ +

(λ: thermal conductivity, t: thickness of the container cylinder, L: length of the container cylinder, only 0.1≤t≤0.6 [mm], 4≤L≤20 [mm], 0.005≤λ≤0.1 [W / (mmK) )])

The surrogate characteristic test for deriving the predicted operating time T1 will be explained. The tested thermosensitive switch has a diameter D of 12.8 mm in the cylindrical portion of the container, and a diameter of the thermally actuated plate is 12.0 mm.

In addition, the cover plate is fixed to a cold rolled steel plate (SPCE) having a diameter of 17 mm and a thickness of 1.6 mm. The encapsulating gas inside the container is 75% nitrogen and 25% helium, and the encapsulating gas pressure is 130kPa. .

In the test, the protective cap 13 and the lead wire shown in FIG. 4 were attached to the thermosensitive switch.

In the test method, as described above, the thermosensitive switch operated at 155 ° C. was immersed in only the container part such that other parts such as a lid plate and the like did not come into contact with the silicon oil at 180 ° C., and the time until the switch was operated was measured.

The predicted operating time T1 is within the range of substitution conditions for each value, and the thickness t of the container is 0.1 to 0.6 mm, the length L of the container cylinder is 4 to 20 mm, and the thermal conductivity is limited to the range of iron to stainless steel. It is quite consistent with the operating time in the surrogate test of the thermosensitive switch.

For example, the embodiment stainless steel (SUS304) vessel (having a thermal conductivity of 0.015W / (mm · K)) in case the thickness t of the container 0.3mm, a cylindrical bugil L is 12.1mm T1 is 14.99 seconds, the average measured value of 15.2 Almost matches the second.

Table 1 shows the relationship between the test results of the various samples and the predicted operation time.

In addition, the cylindrical diameter of the switch container is all 12.8mm.

In this way, the predicted operating time T1 is almost identical to the operating time in the surrogate characteristic test of various samples.

From the values and actual values of this empirical formula, it can be seen that the cylinder cylindrical length L is 0.5 times or more the diameter D, and the operation time is improved by about 20% compared with the conventional example.

Specifically, in the case where the length L is 12.8 mm in diameter with respect to 6.8 mm, the conventional example in which the length L shown in FIG. 7 is 5.5 mm is longer than 115 seconds while the measured average value of the operating time is less than 90 seconds. Takes

The response performance as the thermosensitive switch is preferably 90 seconds or less, more preferably 60 seconds or less in this experiment.

In addition, as the thermally sensitive switch excellent in thermal response above these, the thermally sensitive switch shown in the first embodiment, the second embodiment and the third embodiment of Table 1 described above, and its predicted operating time T1 is conventional cold as shown in FIG. In the case of a rolled steel sheet container (thermal conductivity 0.062W / mmK), when the wall thickness t is 0.3 mm and the cylinder length L is 5.5 mm and the entire container is exposed to a refrigerant, Equivalent to or greater than performance.

Examples 1 to 3 using a stainless steel container satisfy each condition as shown in Table 1, and this result was also confirmed in a test conducted by actually attaching it to the control target device.

Also, in Examples 4 and 5 using a cold rolled steel container, the effect of the degree shown in Examples 1 to 3 was not obtained, but the operation time was significantly shorter than that of the conventional example by selecting the cylindrical diameter, length, and thickness of the container. You can do it.

In the case where the container shape is the same as the conventional one from the above calculated values and the results of the experiment, it is sufficient to make the thermal conductivity about 1/2 of iron (λ = 0.075 W / (mm · K)) and about 2/3 or less of conventional steel sheet. The operation speed can be obtained.

In addition, by making the cylindrical portion L of the container longer than before, it is possible to delay the movement of heat to the lid plate and thereby shorten the thermal response time as the heat sensitive switch.

For example, it can be seen from the above empirical formula that if the vessel thickness and thermal conductivity are the same, at least twice as long as the conventional one is required in order to obtain a performance equal to or higher than when the entire switch is exposed to the refrigerant.

The cross-correlation obtained by this formula is particularly suitable for high accuracy when the diameter of the cylindrical portion of the thermosensitive switch container is in the range of 8 to 15 mm.

Equation 2 is to determine the constants A and B of Equation 1 in accordance with the test results of the thermosensitive switch of the shape specifically used in the embodiment, for example, by changing the diameter of the thermosensitive switch container, etc. By setting according to the new condition, a value close to the actual operation time can be obtained.

However, the thermal responsiveness of the thermally sensitive switch can be improved by making the thermal conductivity of the encapsulated gas enclosed inside the switch container good.

However, the gas encapsulated in the switch container may transfer heat from the switch container to the thermally active plate and at the same time cause convection in the container.

However, in the switch structure of the embodiment, since the thermally active plate is close to the bottom of the container, it is confirmed that the heat transferred to the thermally active plate through the encapsulation gas acts more effectively than the heat transfer to the cover plate by convection. In the case of detection, it turned out that it is effective to adjust the enclosed gas to a state with good thermal conductivity, and to change, for example, to raise the helium ratio in the enclosed gas, or to raise the enclosed gas pressure.

As a result, the thermosensitive switch has normality over a long period of time by enclosing a predetermined gas in an airtight container, but as the enclosed gas, helium gas is enclosed together with dry air or nitrogen for airtight inspection.

Since helium has a higher thermal conductivity than dry air or nitrogen, the helium ratio of the encapsulated gas is increased to increase the thermal conductivity of the encapsulated gas, thereby rapidly transferring the heat of the container back to the thermally active plate.

Helium is six times more thermally conductive than nitrogen or air, making it easy to transfer heat from the vessel to the thermal actuating plate, especially during rapid temperature rises.

For example, in a thermosensitive switch operating at 155 ° C using a steel plate in a container, a switch having a helium of 25%, 50%, and 75% of the encapsulated gas is prepared, and only the container part of each switch is 180 Compared to experiments measuring the time to operation by immersing in oil at ℃, helium is 50% response time than 25% than 5%, again 75% response time than 25% As a result, the improvement was about 10 to 15%.

like this The helium of 50% or more can speed up the temperature rise rate of the thermal actuating plate against the temperature rise within a short time of the refrigerant gas of the heat chain compressor.

Again preferably, helium is preferably 75% or more.

If the helium is close to 100%, the breakdown voltage between the contacts at the time of opening of the contacts decreases, but there is no practical problem in the use of the battery voltage of a car or the like.

However, in the inspection process at the time of manufacture, when the inspection of the contact-to-contact distance is performed by measuring the breakdown voltage between the contacts, the determination range becomes difficult because the voltage range is narrowed.

The upper limit is preferably 95%.

When the vessel is made of stainless steel using the thermosensitive switch of FIG. 1, the latter is used in the oil substitute test when comparing the use of helium 25% -nitrogen 75% as the encapsulation gas and the use of helium 75% -nitrogen 25%. The operating time is 20% shorter than the former.

In this case, the change rate is larger than that of the steel plate used in the vessel. As described above, since the bottom temperature of the vessel rises quickly because of the low thermal conductivity of the stainless steel, it is more effective to change the gas to transfer this heat efficiently to the thermally active plate. I think.

In the above-described embodiment, the use of stainless steel in the vessel of the thermosensitive switch has been described as an example. In addition, the thermal conductivity of the iron-nickel alloy, the iron-chromium alloy, the nickel-chromium alloy, the nickel-copper alloy, etc. is 1 for iron. An equivalent effect can be obtained by selecting a metal of less than / 2, preferably a metal having a thermal conductivity of 1/3 or less of iron.

In a conventional thermally sensitive switch, solder is used to secure the lead wire and the switch using solder.

However, because the solder has a relatively low melting temperature, such a thermally sensitive switch could not be used due to the risk of peeling off the lead wire under conditions such as being exposed to heat exceeding 200 ° C.

In the present invention, as shown in FIG. 5, the lead wires 12A, 12B are directly conductively fixed to the conductive pins 4A, 4B of the thermally sensitive switch 1 by a resistance welder or the like.

For this reason, compared with the conventional lead wire fixed with solder, even when exposed to a high temperature environment, the electrical connection between the lead wire and the switch is reliably maintained, so that it is possible to be a temperature switch operating at a higher temperature than the conventional one.

As described above, according to the present invention, the heat conduction from the bottom of the container to the heat conduction plate and the heat conduction through the cylindrical part in the direction of the lid plate are established by setting the cylindrical part diameter, thickness, and length of the metal container of the thermosensitive switch to form a predetermined relationship. Are defined respectively, and as a result, the temperature rise speed of the thermally actuated plate can be improved to increase the response speed as the thermally sensitive switch.

In addition, the thermal conductivity of the metal container is lower than that of the steel sheet used in the past, and preferably, the thermal conductivity is 1/3 or less of iron, for example, stainless steel can be used to suppress heat from escaping to the outside through the container. The heat of the refrigerant can be effectively and quickly transferred to the thermally active plate accommodated in the container.

Again, helium is encapsulated in a sealed container at a rate of 50% to 95%, so that the heat of the container can be quickly transferred to the thermally activated plate, especially when the temperature of the heat medium such as the refrigerant gas of the compressor rises rapidly.

According to the present invention, a stepped portion is formed near the circumferential peripheral portion of the lid plate so that the inner circumferential surface of the container almost contacts the outer circumferential portion of the lid plate. Intrusion into the container can be prevented, and alignment of the lid plate and the container at the time of assembly can be facilitated by such a configuration.

In addition, the present invention can fix the lead wire to each of the first and second terminals to obtain a thermally sensitive switch that can be used in a high temperature environment as well as conventional soldering iron information.

Claims (24)

Drilling through the metal disk-shaped lid plate and two through-holes, and supplying electrically insulating filling material to each of the holes in an airtight manner to hold the first and second terminals, and to close the outer circumference of the lid plate. A metal container comprising a cylindrical portion having a spherical terminal and a bottom plate portion having a shallow dish shape, the open-plate terminal being welded to the lid plate to form a hermetically sealed container, and a rapid inversion operation at a first temperature on the inner bottom of the container. And accommodating a disc-shaped heat-activated plate formed in a shallow dish shape so as to rapidly reverse to the second temperature, arranging a retaining plate elastically opposed to the heat-actuated plate, and further providing a fixed contact member to the first terminal. The movable contact member is welded to each of the two terminals, and the movable contact member is provided with a pressure receiving member opposed to the thermally active plate, and the fixed contact member and the movable contact member are described above. When the welding jig is placed in the same direction to each of the two terminals and on an extension line including the respective terminal center and the welding point, the thermally sensitive switch having the welded portion welded so that the other terminal does not interfere with the placement of the jig. In the metal container, the thickness of the metal container is set to 1/60 to 1/20 of the diameter of the cylindrical part, and the length of the cylindrical part is set to 0.5 times or more of the diameter. A heat sensitive switch characterized in that the heat conduction through the cylindrical portion in the direction of the cover plate is regulated, respectively, and the temperature rising speed of the heat actuating plate is adjusted. Perforated metal disc cover plate and two through-holes in the cover plate, each of which is electrically sealed with an electrically insulating filling material to hold the first and second terminals, and close to the outer circumference of the cover plate. A metal container comprising a cylindrical portion having an open end terminal and a bottom plate portion having a shallow dish shape, the open end terminal being welded to the lid plate to form a sealed container, and a predetermined first temperature along the inner bottom of the container. A first plate insulated and retained on a lid plate to accommodate a disc-shaped heat-activated plate formed in a shallow dish shape so as to suddenly invert to a second temperature, and to face the heat-activated plate. The fixed contact member is welded to the terminal and the movable contact member is welded to the second terminal, respectively, and the movable contact member is provided with a pressure receiving member opposed to the thermally actuated plate. And the other terminal is welded so that the other terminal does not interfere with the placement of the jig when the movable contact member is arranged in the same direction in each of the two terminals described above and on an extension line including the respective terminal center and the welding point. A thermosensitive switch having a welded portion, wherein the metal container is made of a metal having a thermal conductivity of less than 1/2 of iron, thereby suppressing the thermal conductivity to the lid plate side when the container portion is heated, thereby increasing the temperature rising speed of the bottom of the container. Thermal switch. The method of claim 2, The metal container has a thickness of 1/60 to 1/20 of the cylindrical part diameter, and a cylindrical part length of 0.5 times or more of the diameter, so that the heat conduction to the inside of the container and the cylinder from the bottom of the container to the lid plate direction. A heat sensitive switch characterized in that it defines the heat conduction through the negative and adjusts the speed of temperature rise of the thermal actuating plate. The method of claim 2, A metal vessel is a thermosensitive switch, characterized in that composed of any one of iron-chromium alloy, iron-nickel alloy, iron-nickel-chromium alloy or nickel-chromium alloy. The method of claim 3, A metal vessel is a thermosensitive switch, characterized in that composed of any one of iron-chromium alloy, iron-nickel alloy, iron-nickel-chromium alloy or nickel-chromium alloy. The method of claim 1, A thermosensitive switch characterized in that a sealed gas containing 50 to 95% helium is sealed at a pressure higher than atmospheric pressure in a sealed container. The method of claim 2, A thermosensitive switch characterized in that a sealed gas containing 50 to 95% helium is sealed at a pressure higher than atmospheric pressure in a sealed container. The method of claim 3, A thermosensitive switch characterized in that a sealed gas containing 50 to 95% helium is sealed at a pressure higher than atmospheric pressure in a sealed container. The method of claim 4, wherein A thermosensitive switch characterized in that a sealed gas containing 50 to 95% helium is sealed at a pressure higher than atmospheric pressure in a sealed container. The method of claim 5, A thermosensitive switch characterized in that a sealed gas containing 50 to 95% helium is sealed at a pressure higher than atmospheric pressure in a sealed container. The method of claim 1, And a stepped portion formed near the circumferential circumference of the cover plate such that the inner circumferential surface near the open end terminal of the container almost contacts the outer circumference of the step portion of the cover plate. The method of claim 2, And a stepped portion formed near the circumferential circumference of the cover plate such that the inner circumferential surface near the open end terminal of the container almost contacts the outer circumference of the step portion of the cover plate. The method of claim 1, A heat sensitive switch, wherein a lead wire is fixed to each of the first and second terminals by welding. The method of claim 2, A heat sensitive switch, wherein a lead wire is fixed to each of the first and second terminals by welding. The method of claim 3, A heat sensitive switch, wherein a lead wire is fixed to each of the first and second terminals by welding. The method of claim 4, wherein A heat sensitive switch, wherein a lead wire is fixed to each of the first and second terminals by welding. The method of claim 5, A heat sensitive switch, wherein a lead wire is fixed to each of the first and second terminals by welding. The method of claim 6, A heat sensitive switch, wherein a lead wire is fixed to each of the first and second terminals by welding. The method of claim 7, wherein A heat sensitive switch, wherein a lead wire is fixed to each of the first and second terminals by welding. The method of claim 8, A heat sensitive switch, wherein a lead wire is fixed to each of the first and second terminals by welding. The method of claim 9, A heat sensitive switch, wherein a lead wire is fixed to each of the first and second terminals by welding. The method of claim 10, A heat sensitive switch, wherein a lead wire is fixed to each of the first and second terminals by welding. The method of claim 11, A heat sensitive switch, wherein a lead wire is fixed to each of the first and second terminals by welding. The method of claim 12, A heat sensitive switch, wherein a lead wire is fixed to each of the first and second terminals by welding.