JPH0727621A - Closed-type heat sensitive device - Google Patents

Abstract

PURPOSE:To provide a heat sensitive device, which can be used in the container of a closed-type electrically-driven compressor and can be used by winding around the winding of a motor. CONSTITUTION:A closed-type heat sensitive device 1 constitutes the closed-type container having the pressure resisting property with a housing 2 made of a metal and a cover 3. A through hole 2A is provided in the housing 2. A conducting pin 4 is fixed with an electrically insulating filler 5 in an airtight mode. A heat sensitive resistor element 6 is arranged in the closed-type container. Terminals 6A and 6B of the element 6 are connected and fixed to the inner surface of the container and the conducting pin 4, respectively. Bent parts 6C and 4A are provided at the terminal 6A of the heat sensitive element 6 and the conducting pin 4, respectively. The stress caused by the thermal expansion and contraction of each part generated in the using temperature region is absorbed. Therefore, the heat sensitive element can be used inside the closed- type electrically-driven compressor or can be used by winding the element around the winding of a motor. At the same time, breakdown caused by the stress can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive device used as a protective device for a hermetic electric compressor or the like.

[0002]

2. Description of the Related Art Conventionally, as this type of temperature sensitive element, a fuse using wax, a low melting point fusible alloy or the like, a temperature sensitive resistance element such as a thermostat or a thermistor using bimetal or the like has been used. .

[0003]

In order to quickly detect an abnormality in the electric motor of the hermetic electric compressor, a temperature sensitive element is wound around the winding of the electric motor, for example, and is placed inside the hermetic container of the hermetic electric compressor. It is installed and the power supply to the electric motor is shut off when there is an abnormality due to overheating of the electric motor.

However, even if the electric motor is normal, the temperature sensitive element may operate due to transient heat generation at the time of starting. In such a case, normal operation can be performed by restarting after the temperature of the electric motor has dropped. However, if the temperature-sensitive element installed in the closed container of the hermetic electric compressor is like a fuse, once the fuse is blown, the hermetic motor will be normal even though the electric motor is normal. Since it itself becomes unusable and it is virtually impossible to replace the fuse, it is necessary to replace the entire hermetic electric compressor in a refrigeration system or the like.

Further, in the temperature-sensitive switch using a bimetal or the like, even after the contact is interrupted at the time of an abnormality, the temperature is restored by the temperature of the electric motor or the like, so that there is no problem as described above. However, recently, it is required to control the electric motor in proportion to its temperature instead of on / off control.

A temperature sensitive resistance element such as a thermistor whose resistance value changes in proportion to temperature is suitable for the above control. However, since the inside of the hermetically sealed container of the hermetic electric compressor is affected by refrigerant, lubricating oil, etc., it cannot be used as it is as long as it is covered with rubber or the like. However, glass-encapsulated thermistors and those molded with epoxy resin are not strong enough, so it is difficult to wind them in the winding of the electric motor, and the pressure inside the hermetically sealed container of the hermetic electric compressor rises to 50 atm or more in case of abnormality. Because sometimes
It was impossible to install the thermistor in the closed container of the hermetic electric compressor.

[0007]

A feature of the present invention is that it has an open end, a through hole is formed in a portion other than the open end, and the through hole is made of at least one container made of an electrically insulating airtight filler. A first container made of metal to which a conductor penetrating the inside and the outside of the container is fixed, and a second container made of metal that hermetically closes the container by joining the open ends of the container to form an airtight container. In a configuration in which a temperature sensitive element whose electric resistance changes according to a change in temperature is installed in the closed container,
When the terminals of the temperature-sensitive element are conductively fixed between the inner surface of the container and the conductor, the temperature-sensitive element or the conductor is stressed due to thermal expansion and contraction within the operating temperature range of the temperature-sensitive element. The sealed heat-sensitive device is characterized in that it is arranged so as not to impair the function of.

Another feature of the present invention is that the space in the closed container of the closed type heat sensitive device is filled with a gas having a better thermal conductivity than air.

Further, a feature of the present invention is that airtightness can be easily and highly accurately determined in a product quality test.

Another feature of the present invention is that the inner surface of the closed vessel of the closed type heat-sensitive device and the surface of the temperature-sensitive resistance element are connected by a substance having good thermal conductivity.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 is a vertical sectional view of the present invention, and FIG. 2 is a view taken along the line AA in FIG. The container of the sealed thermosensitive device 1 is composed of a metal housing 2 as a first container and a metal cover 3 as a second container. A through hole 2A is provided in the housing 2, and a conductor 4 is inserted into the through hole 2A and is hermetically fixed by an electrically insulating filler 5 such as glass. The housing 2 and the cover 3 are hermetically sealed at a peripheral edge portion 2B, which is an open end thereof, to have pressure resistance by air-tightly fixing them by ring projection welding or the like.

A temperature sensitive resistance element 6 whose resistance value changes in proportion to temperature, such as a thermistor, is enclosed in the inside of this hermetic container, and one terminal 6A thereof is a metal container, in the embodiment a housing. 2 is conductively connected and fixed by welding or the like, and the other terminal 6B is also conductively connected and fixed to the conductor 4. Here, the stress due to the thermal expansion and contraction of the metal portion or the like generated during welding and in the operating temperature range of the heat sensitive device 1 is elastically absorbed by the bent portion 4A of the conductor 4 and the bent portion 6C of the terminal 6A. It is configured. Therefore, the stress related to the temperature-sensitive resistance element 6 can be reduced, and the temperature-sensitive resistance element can be prevented from being broken due to thermal expansion or contraction of each part.

Lead wires 7A and 7B for connecting to a control device are connected to the outside of the metal housing 2 and the outside end of the conductor 4 of the container, respectively. Also lead wire 7
Protective portion 8 made of an electrically insulating resin or the like that covers the welded portions of A and 7B and protects the welded portions and fixes the lead wires.
Is provided.

According to the present invention, since the temperature-sensitive resistance element is enclosed in the pressure-resistant airtight container, even if the thermistor or the like is not sufficient in strength as it is, it may be wound around the winding of the electric motor or the hermetic electric compressor. It is possible to install it in a closed container. In addition, since the stress-absorbing portion is provided between the temperature-sensitive resistance element and the container or the conductor, the temperature-sensitive resistance element will not be destroyed by the stress due to thermal expansion or contraction of each portion.

Next, FIG. 3 shows another embodiment of the present invention. The sealed thermosensitive device 11 of FIG. 3 has a sealed container including a bottomed cylindrical housing 12 that is a first container and a lid plate 13 that is a second container. A through hole 13A is provided in the cover plate 13, and a conductor 14 is inserted into the through hole 13A and is airtightly fixed by an electrically insulating filler 15.

A temperature sensitive element 6 is installed inside the airtight container, and one terminal 6A thereof is electrically connected and fixed to the inner surface of the closed container, in this embodiment, the inner surface of the lid plate 13 by welding or the like. The other terminal 6B is electrically connected and fixed to the end of the conductor 14 on the inner side of the container by welding or the like.
At this time, the terminals 6A and 6B are each provided with a bent portion 6C for absorbing stress, so that the stress due to thermal expansion and contraction of the metal portion of the heat sensitive element does not directly act on the heat sensitive element 6, and the heat sensitive to the heat sensitive element The destruction of the element can be eliminated.

Next, FIG. 4 shows another embodiment of the present invention. The closed thermosensitive device 21 of FIG. 4 comprises a cylindrical housing 22 as a first container and a cover 23 as a second container to form a closed container. A through hole 22A is provided in the housing 22, and a conductor 24 is inserted into the through hole 22A and is hermetically fixed by an electrically insulating filler 25.
A temperature sensitive element 6 is installed inside the airtight container, one terminal 6A of which is electrically connected and fixed to the inner surface of the closed container, that is, the inner surface of the housing 22 in this embodiment, and the other terminal 6B.
Is electrically connected and fixed to the end of the conductor 24 on the inner side of the container. In the present embodiment as well, similarly to the above-described example, the terminals 6A and 6B are provided with the bent portions 6C for absorbing stress, respectively, so that the heat-sensitive element of You can eliminate the destruction.

In this embodiment, a gas containing at least 5% helium, for example, a gas containing 90% argon and 10% helium is substituted and sealed in a closed container of the closed type heat-sensitive device. In this way, by substituting and enclosing a gas having good thermal conductivity such as argon or helium in the closed container, it is possible to transfer the heat from the heating element such as the winding of the electric motor or the refrigerant to the temperature sensitive resistance element. Also, by filling the enclosed gas with helium, it is possible to use a helium leak detector during the airtightness test, so it is possible to detect even a very small leak of 1 × 10 ^-9 atm cc / sec or less. It is possible to perform a more accurate airtight inspection compared to the one in which air is enclosed.

Further, an electrically insulating paste 9 having a good thermal conductivity such as a silicon paste is applied between the housing 2 and the temperature sensitive element 6 as shown in FIG. 5 (A), or as shown in FIG. 5 (B). The thermal response of the temperature sensitive element 6 can be further improved by filling and sealing the sealed gas instead of the sealed gas. In FIG. 5, the same parts as those in the above-described embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The temperature sensitive resistance element may be a positive characteristic thermistor or a negative characteristic thermistor depending on the specifications of the control device.
For example, a so-called thermocouple or a thin-film metal resistor such as platinum may be used. Further, the temperature-sensitive resistance element may be glass-encapsulated, may be coated with a resin such as epoxy, or may be uncoated.

[0021]

According to the present invention, since the temperature-sensitive resistance element is enclosed in the metal pressure-resistant airtight container, the temperature-sensitive resistance element whose strength is insufficient as it is may be wound in the winding of the electric motor or the hermetically-sealed electric compressor. It is possible to have a structure that can withstand applications requiring strength and airtightness such as installation in a space such as inside a closed container.

Further, by providing a portion for absorbing stress due to thermal expansion and contraction between the temperature-sensitive resistance element and the connecting portion between the inner surface of the container and the conductor, destruction of the temperature-sensitive resistance element due to stress is prevented. You can

Further, by enclosing and filling a gas or paste having a good thermal conductivity in the closed container, it becomes possible to transfer the external heat to the temperature sensitive resistance element faster. Further, by using helium as the gas to be enclosed, highly accurate airtightness inspection can be easily performed.

[Brief description of drawings]

FIG. 1 shows an embodiment of a sealed heat-sensitive device of the present invention.

FIG. 2 is a cross-sectional view taken along the line AA of the sealed thermosensitive device of FIG.

FIG. 3 is another embodiment of the sealed thermosensitive device of the present invention.

FIG. 4 is another embodiment of the sealed thermosensitive device of the present invention.

FIG. 5 is another embodiment of the sealed thermosensitive device of the present invention.

[Explanation of symbols]

 1, 11, 21: Closed type heat sensitive device 2, 12, 22: Housing (first container) 3, 23: Cover (second container) 4, 14, 24: Conductor 5, 15, 25: Electrical insulation Filling material 6: Temperature-sensitive resistance element 6A, 6B: Terminal 6C: Bent portion 7A, 7B: Lead wire 8: Protective portion 9: Good thermal conductive paste

[Procedure amendment]

[Submission date] August 31, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

Claims (4)

[Claims] 1. A conductor having an open end, a through hole being formed in a portion other than the open end, and the through hole being formed by an electrically insulative airtight filler to penetrate at least one container inside and outside. A first container made of metal to which is adhered and a second container made of metal that hermetically closes the open end of the container by joining the open end of the container to form a hermetically sealed container and In the one in which the temperature-sensitive element whose resistance changes is installed in the closed container, the terminals of the temperature-sensitive element are electrically conductively fixed between the inner surface of the container and the conductor,
A sealed heat-sensitive device, which is arranged so that the function of the temperature-sensitive element or the conductor is not impaired by stress due to thermal expansion and contraction within the operating temperature range of the temperature-sensitive element. 2. The hermetically sealed thermosensitive device according to claim 1, wherein a gas having a higher thermal conductivity than air is enclosed in the space in the hermetically sealed container. 3. The sealed thermosensitive device according to claim 2, wherein the gas sealed in the sealed container contains at least 5% or more of helium. 4. The hermetically sealed thermosensitive device according to claim 1, wherein the inner surface of the hermetically sealed container and the surface of the temperature sensitive resistance element are connected by a substance having good thermal conductivity.