KR930000089Y1 - Thermally resonsive switch - Google Patents

Abstract

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Description

Thermal switch

1 is a longitudinal side view of a thermally active switch according to an embodiment of the present invention.

FIG. 2 is a plan view of the lid of the thermally actuated switch seen from the arrow direction along the line II-II of FIG.

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

4 is a plan view of the resistance heating element disposed in the thermally active switch shown in FIG.

FIG. 5 is a front view of a resistance heating element disposed in the thermally active switch shown in FIG.

6 is a side view of the resistance heating element disposed in the thermally active switch shown in FIG.

7 is a plan view of a resistance heating element in another embodiment.

8 is a front view of a resistance heating element in another embodiment.

9 is a side view of the resistance heating element in another embodiment.

* Explanation of symbols for main parts of the drawings

1: container 1a: spherical shape

1b: middle part 1A: small protrusion

2: Thermal Response Plate 2A: Movable Contact

2B: dish-shaped portion 3: support

4: Covering Body 4A, 4B: Through Hole

4C: protrusion 5A, 5B: electrically insulating filler

6A, 6B: conductive pin 7: fixed contact

7A: silver alloy contact member 8: resistance heating element

8A: Once

The present invention relates to a thermal actuating switch which drives a movable contact to open and close an electric current between a fixed contact paired with a movable contact by a thermal actuating plate which is deformed according to a temperature change such as a bimetal or a trimetal, in particular, a refrigerator It is housed in an enclosed housing together with a motor, refrigerant gas, and lubricating oil that operates a compressor such as an air conditioner.The main purpose is to protect the motor from overheating and overcurrent by responding quickly to the temperature of the motor or refrigerant gas. It relates to a hermetic thermal switch.

Conventionally, various kinds of such thermally active switches have been proposed.

For example, fix a fixed contact near the closed end of a cylindrical box like the thermostat switch shown in JP 61-24118, and electrically insulate the terminal pin to a header welded to the open end in an airtight manner. Attached to a thermally active element such as a bimetal having a movable contact on the terminal pin, or a sealed thermally active relay shown in Japanese Laid-Open Laboratory No. 58-40505.

However, the conventional thermostat switch shown in Japanese Patent Application No. 61-24118 has a process of welding a contact in the vicinity of a closed end deeply entered from the open end of a long narrow container, but its workability is very bad and its position Identification and quality assurance inspections were difficult.

In addition, the end movable contact of the bimetal element provided on the terminal pin electrically insulated from the header serving as a cover welded to the opening of the container is sealed by matching the fixed contact in the vicinity of the closed end with a predetermined positional relationship. There were difficulties in process control.

In addition, in the case of accommodating a heating element having a larger resistance value compared with the resistance of a bimetal element, there are various problems such as a drawback that a plurality of terminal pins insulated from each other and fixed to the header portion cannot be made very large and compact. .

In addition, for the sealed thermal reaction relay shown in the above-mentioned Japanese laboratory No. 58-40505 designed by the applicant of the present application, in the first outer shell and the second outer shell constituting the sealed container, the second outer shell serves as a simple cover. It is only present, and since the heat-resistant plate having fixed contact and movable contact is installed at the first outer shell, the outer shape is much larger than that of the heat-resistant plate, which is disadvantageous to be miniaturized. A method of correcting the operating temperature of the oscillation element is adopted, and since the structure of the sealed container is separated from the deformation force from the outside, the correction temperature is likely to change with respect to the impact force, and thus there is a disadvantage that the reliability thereof is inferior.

In order to solve this problem, if it is replaced by a design change such as increasing the thickness of the member, it causes too much economic loss and slows down the thermal response. Also, the rated output of the motor to be protected by this switch has a wide range of different load currents. There were faults such as being difficult to fit.

The present invention devised to solve the above-mentioned general defects, the main purpose of the present invention can easily secure the desired precision of the relative positional relationship between the contact point and the dimension relationship of each part, assembly work, operating temperature It is to provide a thermally active switch that is easy to calibrate.

Another object of the present invention is to provide a thermally active switch capable of maintaining a long time the desired predetermined operating characteristics.

Another object of the present invention is to provide a compact and robust thermal actuation switch.

In order to achieve the above object, the present invention consists of a thermally active switch, which will be described in detail below with reference to the accompanying drawings.

One side is opened along the longitudinal direction, and both ends of the longitudinal direction form a substantially hemispherical shape, and a section of the hemispherical ship-shaped container 1 in which the section cross-section between these both ends is substantially arcuate, and this vessel-shaped container 1 A conductive material support 3 having one end secured in a conductive state inside the hemispherical portion 1a, which is one end side thereof, is disposed in the vessel-shaped container 1, and one end is fixed to the other end of the support 3, and the other end In order to regulate the movement range, the heat-sensitive plate 2 opposed to the inner surface of the hemispherical surface portion 1a, which is the other end side of the vessel-shaped container 1, through a predetermined space, and an approximately center portion of the heat-sensitive plate 2 A shallow dish-shaped upper portion 2B for snapping movement is formed, and by means of welding around the periphery of the opening to hermetically close the opening of the vessel-shaped container 1 in which the movable contact 2A is fixed at the other end. Fixed and formed into a wall thicker than the wall thickness of the vessel-shaped container (1). The metal lid 4 having the through-hole 4A and the through-hole 4A of the lid 4 are hermetically penetrated through the electrically insulating filler material 5A, and the vessel-shaped container 1 The support pin of the hemispherical portion 1a of the vessel-shaped container 1 and the conductive pin 6A having the fixed contact 7 fixed to the movable contact 2A in contact with and separated from the movable contact 2A. The vicinity of the portion (3) fixed is characterized in that the inner deformation portion (C) deformed to adjust the contact pressure between the contact points (2A), (7).

According to the thermally actuated switch of the present invention configured as described above, the alignment of the movable contact of the thermally actuated plate provided on the hemispherical vessel-shaped container side and the fixed contact provided on the cover body side is made very easy because the vessel is a shallow vessel shape.

In this thermally active switch, the range of motion of the thermally active plate is determined by the distance between the stationary contact and the inner surface of the hemispherical vessel container, which is used when the hemispherical vessel container and the cover are hermetically welded. Assuming that the amount to be shortened by melting of the contact portion is assumed in advance, it is accurate.

In this case, since there is no space margin more than necessary, the movement range of the movable contact is narrowed when acceleration such as an impact is applied, so that an abnormality (error) of operating temperature is reduced.

Since the thermally actuated switch is provided with a conductive terminal on the side of the cover, even though the overall size is compact, a plurality of conductive terminals can be installed, so that the thermal response that can sufficiently cope with a small rated output of the motor to be protected is large. The space enough to install the heat generating resistor which has a desired resistance value connected in series with a copper plate can be ensured.

In addition, in this thermally active switch, since the operating temperature is extensively configured, it is difficult to impair the sealability of the container as a result of the fact that the amount of deformation applied to the vessel-shaped container is completed.

Of course, from the above various features, a thermally active switch applicable to a wide range of motor rated outputs can be obtained.

Next, an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

The dome vessel container 1, which is formed by drawing a sheet metal by pressing, has a spherical portion 1a at both ends in the longitudinal direction, and the middle portion 1b has a semicircle shape. It has a hemispherical ship shape as a whole, and its open end is located at the right end II-II line part shown.

Inside the hemispherical container 1, there is a planar shape made of bimetal or an almost quadrangular or elliptical shape, and a well-known thermal copper plate provided with a shallow dish-shaped drawing part for snapping in the center. (2) is disposed, and the movable contact 2A made of silver alloy is fixed in the upper direction shown as the movable end side in the same manner as spot welding, and the fixed end side in the downward direction in the first drawing is made of a suitable metal plate. (3) is fixed in the same manner as spot welding, and the first direction of the support 3 is in the same way as spot welding as indicated by the X mark on the lower spherical portion of the hemispherical vessel-shaped container 1. It's challenging.

At the open end of the hemispherical ship-shaped container 1, the lid 4 formed by press-processing an iron plate thicker than the container has the left open end of the first figure as the open end of the hemispherical ship-shaped container 1. And are hermetically sealed in the same manner as a ring projection weld.

Before the airtight seal, the lid 4 is provided with through holes 4A and 4B near its center, and the through holes are electrically insulating fillers 5A, such as glass, each having an appropriate coefficient of thermal expansion. And (5B), the conductive pins 6A and 6B are hermetically fixed by a well-known compression type hermeticseal.

In addition, the fixed contact 7 which is fixed by attaching the silver alloy contact portion 7A to the conductive pin 6A is welded to each other in a substantially orthogonal shape as shown.

The dimension A between the surface of the silver alloy contact member 7A of the fixed contact and the open end of the lid 4, that is, the II-II line shown in the drawing, can be easily managed as described later.

4 C of small area protrusions are formed in the downward direction of the cover body 4 by press working, etc. The resistance heating body 8 which welded one end 8A to this protrusion 4C part and was fixed was carried out. The other end 8B is fixed to the conductive pin 6B by welding or the like.

When the open end face of the lid 4 and the open end face of the hemispherical ship-shaped container 1 are hermetically welded, for example, the shortening amount of the dimension A between both by melting the member by welding of about 0.2 mm After considering in advance, the state in which the curved surface of the plate-shaped portion 2B is inverted by a predetermined temperature in the upper spherical portion 1a of the hemispherical vessel-shaped container 1 at a predetermined temperature is indicated by a dotted line. The size B between the small thermal projection plate 2 and the small projection 1A in the state indicated by the solid line shown at room temperature is provided in advance when a small projection 1A is provided to regulate the range of motion of the thermally conductive plate. Molded.

Then, correcting the operating temperature so that the thermally actuated plate 2 reverses to a predetermined temperature, for example, 150 ° C, is indicated by a downward arrow C shown in FIG. 1 of the hemispherical vessel-shaped container 1, namely, It is possible to deform the substantively support part of the thermally actuated plate 2 very little.

Since the movable contact 2A of the thermally actuated plate is provided at the support 3 and its tip, the slight displacement of the arrow C portion is greatly enlarged as the displacement of the movable contact 2A, and a wide range of contact pressures can be set. This is made possible by a slight deformation of the wall of the container which hardly affects the pressure resistance of the shape container.

When the thermal actuation switch is connected to the motor circuit so that the entire current flowing through the motor flows through the conductive pins 6A and 6B, the electric current of the motor is conducted through the conductive pins 6A-fixed contacts 7-movable contacts 2A. -Thermally active plate (2)-Support (3)-Hemispherical vessel-shaped container (1)-Projection (4C)-Resistance heating element (8)-Conductor (6B) of cover (4).

When the current flowing in the motor is a normal operating current including a large current for a short time at start-up, the thermal actuating plate 2 accepts heating by the total calorific value of the converter, but the temperature in this case is a predetermined operating temperature, For example, since the motor does not reach 150 ° C as described above, the motor continues to be operated.

If any abnormality occurs and the load of the motor is increased to increase the current during operation and this continues, or the internal refrigerant gas becomes abnormally high temperature, the temperature inside the sealed housing where this thermal switch is installed, that is, the ambient temperature of the switch In operation, the operating current cuts off the electric current of the motor by operating the switch in normal operation.

If the torque of the load is greater than the transmitter torque, the rotor is in a restrained state. As a result, if the excessive current at startup continues longer than the time required for normal startup, e.g., 2 to 3 seconds, it is received from the ambient temperature of the switch. The heat generation amount inside the switch increases more than the limit by the resistance heating element 8 rather than heating, and the thermal actuating plate 2 inverts in a snap operation at the seating position shown in FIG. Since the movable contact 2A is separated from the fixed contact 7, the energization to the motor is interrupted.

When it cools naturally in that state, for example, it becomes 90 degreeC, a thermally actuated plate snaps back to the state which displays the curved direction again by a solid line again from a change point line state.

As shown in Figs. 4 to 6, the shape of the resistance heating element 8 shown in Fig. 2 belongs to a large class among these switches, and therefore, it is suitable for a small current rated electric motor, but at the same time. As the conductive material constituting (8), a material having a different intrinsic resistance is selected to match the rated current of the motor, so that the protection characteristics can be changed as described later.

Except for the shape of the resistance heating element shown in FIGS. 4 to 6, for example, as shown in FIGS. 7 to 9, the shape represented by the symbol 18 having almost half of the entire length is shown in FIG. It is attachable in place of the resistance heating element 8 of the switch which is an embodiment.

In other words, it can be seen that the resistance heating element 18 may weld one end 18A to the protrusion 4C of the lid 4 and the other end 18B to the conductive pin 6B.

According to other needs, a resistance heating element can be designed in which arbitrary combinations of conductive materials having different lengths and cross sections, as well as resistivity, can be designed. One end of the resistance heating element is welded to the conductive pin 6B, but the other end of the cover body 4 is formed. It is good to weld to arbitrary parts, and it is clear that projection 4C is not necessarily limited to the position shown, For example, you may change it to the upper side of the cover body 4 of FIG.

When considering the fixing by welding as the material of the resistance heating element, the workability is good and considering the heat resistance, etc., molybdenum, iron, nichrome steel, iron chromium steel, etc. are suitable, and the resistivity is 10 times or more. The combination of overall length and cross-sectional area makes it easy to match a wide variety of motor ratings.

In addition, changing not only the resistance value of the resistance heating element but also the heat capacity, that is, the total volume of the resistance heating element, may change the ON-OFF duty ratio of this thermally active switch so that the protection characteristics can be made as desired.

For example, the resistance value of the converter from the conductive pins 6A to 6B is 0.1 ohm, and the resistance value is the same as in the case of the resistance heating element made by selecting the high resistance as large as shown in FIG. 4 and taking the cross-sectional area as large as possible. In the case of a resistive heating element made by selecting a resistive resistor, which is made thin so that the cross-sectional area is not melted and broken because it is 0.1 ohm, it is short as shown in FIG. 7, the electronic side can obviously lengthen the OFF time with respect to the ON time. The number of ON-OFF cycles can also be reduced by a thermally active switch with the same operating and return temperatures.

Properly determining the ON-OFF duty ratio of this switch can extend the life of the switch or improve the protection characteristics against the large temperature rise rate of the windings when the rotor is constrained as the motor design. This brings about an excellent advantage.

6 and 9, for example, the cross-sectional area of the portion indicated by the symbol N is made smaller than the cross-sectional area of the other portion, and the contact point is reached when the life cycle ends due to the large number of ON-OFF operating cycles of this thermally active switch. It is also possible to have a fuse effect to prevent the part from being closed and becoming overheated.

When this thermally activated switch is used as protection for a single-phase induction motor, it may be necessary to protect it under conditions different from those of the main winding and the auxiliary winding.

For example, when the starter relay is operated by the auxiliary winding to change the capacity of the capacitor between starting and during operation, the case where the contacts of the starting relay are welded and the auxiliary winding side is prevented from abnormally overheating is considered. do.

In such a case, if the main winding and the auxiliary winding are to operate the thermal relay separately as a protective condition, one side of the power supply is electrically connected to the conductive pin 6A of the switch shown in FIG. The thermal response of the present invention is also connected to one end of the main winding of the motor, the conductive pin 6B is connected to one end of the auxiliary winding of the motor, and the other end of the main winding and the auxiliary winding are common. The switch is of course available.

In this case, the main winding current is conducted by conducting pins (6A)-fixed contacts (7)-movable contacts (2A)-thermally active plates (2)-support (3)-hemispherical vessel-shaped container (1)-cover (4) The operating conditions are matched by the circuit resistance of the circuit, while the auxiliary winding current is conducted by conducting pins (6A), fixed contacts (7), movable contacts (2A), thermally active plates (2), supports (3), and lids (4). Since the circuit of the resistance heating element 8-conducting pin 6B flows, the temperature of the thermally actuated plate 2 is increased in the case of the current flowing in the abnormality of the main winding current and the current flowing in the abnormality of the auxiliary winding current, respectively. Although the calorific value may be set to exceed a predetermined value, as described above, the circuit resistance from the conductive pin 6A to the cover 4 needs to be considered with respect to the vector synthesis current values of the main winding and the auxiliary winding.

In FIG. 1, through holes 4A and 4B are provided in the lid 4, but the compression type is applied as a welding sealing method of the conductive pins, so that it is a so-called matching type that matches the coefficient of thermal expansion. If the shape of the through hole is long, the shape of the through hole can be finished as a long one, and two conductive pins can be isolated in the middle of the long circular through hole with a filler such as glass, and arranged in an insulated relationship with each other. .

In addition, when the protection performance is suitable for the electric current of a motor using the conductor of high resistivity for the support body 3, the through-hole 4B, the electrically insulating filler 5B, and the conductive pin 6B are shown in FIG. ), The fixed contact (7)-movable contact (2A)-thermal response plate (2)-support (3)-hemispherical ship-shaped container (1)-cover (6A) The purpose can be achieved through the electric current of the motor to be protected in the circuit of 4).

As described above, the thermally actuated switch of the present invention has a thermally conductive plate that has a movable contact with a support inside the hemispherical vessel-shaped container, and is electrically insulated by welding and sealing the conductive plate to a thick cover body. As a result of adhering to the conductive plate, the fixed contact is firmly fixed to the conductive plate, and the following advantages can be obtained.

The mutual positional relationship between the fixed contact and the movable contact installed at the movable end of the thermally actuated plate can be easily inspected, and the snap contact range of the movable contact is the space between the fixed contact and the peripheral wall of the hemispherical vessel container. As it is regulated by, the possibility of abnormality in the operating temperature and return temperature characteristics of the thermally actuated plate due to impact can be minimized, contributing to the improvement of productivity, and despite the compactness, it is easy to install a plurality of conductive pins as necessary. In addition, it has an excellent effect that the adaptation current range is very wide, more robust and cheaper.

Claims (1)

One side is opened along the longitudinal direction, and both ends of the longitudinal direction form a substantially hemispherical shape, and a section of the hemispherical vessel-shaped container 1 in which the section cross-section between these ends is substantially arcuate, and the vessel-shaped container 1 of A conductive material support 3 having one end fixed in a conductive state inside the hemispherical portion 1a on one end side is disposed inside the vessel-shaped container 1, and one end is fixed to the other end of the support 3, and the other end thereof. In order to regulate the movement range, the heat-sensitive plate 2 opposed to the inner surface of the hemispherical surface portion 1a, which is the other end side of the vessel-shaped container 1, through a predetermined space, and an approximately center portion of the heat-sensitive plate 2 A shallow dish-shaped portion 2B for snapping movement is formed, and a welding means is formed around the entire opening of the vessel-shaped container 1 in which the movable contact 2A is fixed at the other end. Fixed and formed into a wall thicker than the wall thickness of the vessel-shaped container (1) The metallic lid 4 having the through-hole 4A and the through-hole 4A of the lid 4 are hermetically penetrated through the electrically insulating filling material 5A, and the vessel-shaped container 1 The support pin of the hemispherical portion 1a of the vessel-shaped container 1 and the conductive pin 6A having the fixed contact 7 fixed to the movable contact 2A in contact with and separated from the movable contact 2A. And the inner portion (C) deformed to adjust the contact pressure between the contact points (2A) and (7).