JP2003270054A - Sealed heat sensing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat sensing device which is used for a sealed electrically-driven compressor, easily manufactured, and responds at a high speed. <P>SOLUTION: The sealed heat sensing apparatus 1 is constituted of both a housing 6 constituted by airtightly fixing a second metal tube 3 to one end of a first metal tube 2 by an electricity insulating filler 4, and a heat sensing element 5 having a heat sensing resistive element 5A and lead wires 5B and 5C. The heat sensing element 5 is housed in the housing 6, the end of the housing 6 is airtightly sealed to constitute a sealed container, and the lead wires of the heat sensing element 5 are each conductively fixed to the metal tubes. Since it is possible to simultaneously perform both the airtight sealing work of the housing 6 and the connection holding work of the heat sensing element 5 in the sealed heat sensing apparatus 1, it is possible to simplify its manufacturing work. Since the housing 6 itself serves as electrodes, and it is possible to speedily transmit heat received by the housing 6 from a coolant or the like to the heat sensing resistive element 5A through both lead wires at the same time, it is possible to provide a sufficient response speed for the sealed heat sensing apparatus 1. <P>COPYRIGHT: (C)2003,JPO

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 a temperature-sensitive element used in a heat-sensitive device, a fuse using a wax or a low melting point alloy, a thermostat using a bimetal, a temperature-sensitive resistance element using a thermistor, etc. There is.

When continuously controlling the electric motor of the hermetic electric compressor according to the temperature, a thermosensitive device using a temperature sensitive resistance element such as a thermistor whose resistance value changes according to the temperature is used. . In particular, thermistors are made of mechanically fragile materials such as glass and ceramics, so some protection is incorporated into the hermetic electric compressor. As an example of this heat-sensitive device, a temperature-sensitive element 106 such as a thermistor is shown in FIG.
1 shows a heat sensitive device 101 using. This heat sensitive device 101
Is a cover plate 102 in which a lead terminal 104 is airtightly fixed to a hole formed in a metal plate by an electrically insulating filler 105,
It is composed of a temperature sensitive element 106 and a bottomed metal container 103. The temperature sensitive element 106 is composed of a temperature sensitive resistance element 106A and a lead wire 106B.
Is connected to the lead terminal 104 of the cover plate 102. Then, the lid plate 102 and the bottomed metal container 103 are brought into close contact with each other and welded to each other to form a closed container.

[0004]

A conventional heat-sensitive device 101.
In order to electrically conductively fix the temperature sensitive element 106 in the closed container, the lead wire 106B is previously attached to the lead terminal 1 of the cover plate 102.
Then, the cover plate 102 and the bottomed metal container 103 were closely fixed to each other to complete the thermosensitive device 101. Therefore, it was not possible to complete the connection holding of the temperature sensitive element 106 and the closed container in one operation. Also, the heat of the refrigerant of the hermetic electric compressor is mainly used for the bottomed metal container 103.
In order to transfer this heat to the temperature-sensitive resistance element 106A, if the temperature-sensitive resistance element 106A is not in contact with the bottomed metal container 103, this heat is transmitted to the temperature-sensitive resistance element. In order to transmit to 106A, it is conducted to the temperature-sensitive resistance element 106A via the gas in the closed container, or it is further connected to the lead terminal 104 from the bottomed metal container 103 via the lid plate 102 and the electrically insulating filling material 105. Lead wire 106
It was conducted to the temperature-sensitive resistance element 106A via B. Therefore, when the refrigerant temperature of the hermetic electric compressor suddenly rises, a delay may occur until the temperature change is transmitted to the temperature-sensitive resistance element 106A, and the thermosensitive device 101 may not have a sufficient response speed. . In addition, the temperature-sensitive resistance element 106
When A is in contact with the bottomed metal container 103, the heat of the refrigerant of the hermetic electric compressor is directly transferred from the bottomed metal container 103 to the temperature-sensitive resistance element 106A.
As a result, a sufficient response speed can be obtained. However, in order to manufacture a closed container having a structure in which the temperature-sensitive resistance element 106A contacts the bottomed metal container 103, it is necessary to accurately weld the lead wire 106B to the lead terminal 104.

[0005]

In view of the above, the sealed heat-sensitive device of the present invention comprises a housing in which a cylindrical second metal cylinder is hermetically fixed to one end of a cylindrical first metal cylinder with an electrically insulating filler. A temperature sensitive element whose electric resistance changes according to temperature, wherein the second metal cylinder of the housing is thinner than the first metal cylinder and penetrates the filling material, and the temperature sensitive element is a temperature sensitive resistance element. And the lead wire connected to this temperature-sensitive resistance element, this temperature-sensitive element is housed in the housing, and the housing forms a closed container by sealing both ends. In, the lead wire of the temperature sensitive element is arranged in the sealed portion, and the lead wire of the temperature sensitive element is connected and fixed to each metal cylinder together with the sealing of the housing, so that the sealing work and the temperature sensitive element are simultaneously performed. It is characterized by that.

Another feature is that the temperature sensing element as a whole is formed into a shape other than a straight line so as not to impair the function of the temperature sensing resistance element due to the stress applied to each part of the housing and the temperature sensing element. With such a shape, the stress generated by the difference in thermal expansion and contraction of each part of the heat-sensitive device generated within the operating temperature range of the heat-sensitive device is elastically absorbed to prevent the temperature-sensitive resistance element from being destroyed. You can

A characteristic of the temperature-sensitive electric wire device is that it comprises a shielded cable in which a central conductor is covered with a metal conductor and a sealed heat-sensitive device according to claim 1 or 2, wherein the central conductor is a second metal tube of the sealed heat-sensitive device. The noise can be reduced by connecting the conductor, connecting the conductor to the first metal cylinder of the sealed heat-sensitive device, and grounding the conductor.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The sealed heat-sensitive device of the present invention will be described below with reference to FIGS. The sealed thermosensitive device 1 has a housing 6 composed of a first metal cylinder 2 and a second metal cylinder 3. The housing 6 is constructed by hermetically fixing the second metal cylinder 3 to one end of a cylindrical first metal cylinder 2 with an electrically insulating filler 4. The second metal cylinder 3 is thinner than the first metal cylinder 2 and penetrates the electrically insulating filler 4. The open ends on both sides of the housing 6 are hermetically sealed to form a closed container having pressure resistance.

As shown in FIG. 2, a temperature sensitive resistance element 5A such as a thermistor, which changes its resistance value according to temperature, is housed inside the closed container of the closed type heat sensitive device 1 as shown in FIG. This temperature sensitive element 5 has lead wires 5B and 5C at both ends of the temperature sensitive resistance element 5A, one lead wire 5B being conductively connected and fixed to the second metal cylinder 3 and the other lead wire 5C. Are conductively connected and fixed to the first metal cylinder 2. Further, in this embodiment, when the closed type heat sensitive device 1 receives a force from the outside, stress is less likely to be applied to the connecting portion between the lead wires 5B and 5C and the temperature sensitive resistance element 5A, so that the first metal cylinder 2
Also, it is arranged so as not to contact the inner surface of the second metal cylinder 3.

As in this embodiment, the temperature sensitive element 5 has the housing 6 by connecting and fixing the lead wires 5B and 5C to the metal tube.
Held in. Further, the sealed thermosensitive device 1 has a structure in which the housing 6 formed of both metal cylinders receives heat such as a refrigerant, and each terminal of the temperature sensitive element 5 is directly connected to the metal cylinder. Electric conduction and heat conduction can be obtained through the metal cylinder, and the heat received by the housing 6 from the surrounding refrigerant or the like is supplied to the lead wires 5B and 5C.
Conducting through the temperature-sensitive resistance element 5A through the temperature-sensitive resistance element 106A of the conventional example shown in FIG.
The response speed is improved as compared with the sealed thermosensitive device 101 not in contact with 03.

Next, a method of connecting and fixing the temperature sensitive element 5 in the housing 6 of the hermetically sealed thermosensitive device 1 of the present invention will be described. First, as shown in FIG. 3, the temperature sensitive element 5 is inserted into the housing 6 whose both ends are preliminarily opened, the temperature sensitive resistance element 5A is attached to the first metal cylinder 2 of the housing 6, and one lead wire 5B is attached to the first metal tube 2. Two metal cylinders 3 are arranged. Next, as shown in FIG. 4, the open end 6A of the housing 6 is crushed by the welding electrode 7A to sandwich the lead wire 5C. Then, an electric current is applied between the welding electrodes 7A to hermetically seal one end 6A of the housing 6 by resistance welding, and at the same time, the lead wire 5C is also welded and fixed. Next, as shown in FIG. 5, a pipe 8 is connected to the other end 6B of the housing 6, and the gas in the housing 6 is replaced with a desired gas such as a gas having good thermal conductivity or a so-called inert gas through this pipe. To do. After the gas replacement is completed, the welding electrode 7 is provided near the other end 6B of the housing 6 with the pipe 8 connected.
It is crushed by B and the lead wire 5B is sandwiched. Then, an electric current is passed between the welding electrodes 7B to hermetically seal the vicinity of the other end 6B of the housing 6 by welding resistance, and at the same time, the lead wire 5B is also welded and fixed. As described above, in the present invention, the work of hermetically sealing the housing 6 and the work of connecting and holding the temperature sensitive element 5 can be simultaneously performed at both ends, so that work efficiency is improved. In this embodiment, the case where the pipe 8 is connected to one end of the housing 6 and the gas in the housing 6 is replaced with a predetermined gas has been described as an example, but the gas replacement method is not limited to this, and a closed type is also used. If there is no problem in the characteristics and durability of the heat sensitive device 1, the gas replacement work can be omitted. The ends 6A and 6B of the housing that have not been crushed by the welding electrodes 7A and 7B can be trimmed, for example, to adjust the shape of the sealed heat-sensitive device.

Next, FIG. 6 shows a second embodiment of the present invention.
In this embodiment, the same parts as those in the previous embodiment are designated by the same reference numerals and detailed description thereof will be omitted. The housing 6 of the sealed heat-sensitive device 10 of FIG. 6 is configured by hermetically fixing the second metal cylinder 3 to one end of the cylindrical first metal cylinder 2 with the electrically insulating filler 4. The temperature sensitive element 15 is housed in the housing 6, the temperature sensitive resistance element 15A is disposed in the first metal cylinder 2, one lead wire 15B is conductively connected and fixed to the second metal cylinder 3, and the other lead is provided. The wire 15C is conductively connected and fixed to the first metal cylinder 2. At this time, if the temperature-sensitive element 15 in the housing 6 has a straight line shape, problems such as durability may occur. That is, the thermal expansion coefficient of the housing, the thermal expansion coefficient of the metal parts of the lead wires 15B and 15C, and the temperature sensitive resistance element 15 such as a thermistor within the operating temperature range of the sealed thermal device 10.
Since the coefficient of thermal expansion of A itself is different, if the entire shape of the temperature sensitive element 5 is a straight line, the difference between the expansion and contraction causes both lead wires 1
Stress concentrates on the connecting portions of 5B and 15C and the temperature-sensitive resistance element 15A. In particular, when the difference between the upper limit and the lower limit of the operating temperature is large, the stress also increases, so that the temperature sensitive resistance element 15A made of a relatively fragile material may be destroyed and the function of the temperature sensitive element 15 may be impaired.

Therefore, in this embodiment, the lead wire 15C of the temperature sensitive element 15 is provided with a bent portion 15D for absorbing stress, and the heat of each portion of the temperature sensitive element 15 generated in the operating temperature range of the heat sensitive device is provided. The structure elastically absorbs the stress generated by the difference between expansion and contraction. Therefore, directly
It is possible to reduce the stress applied to the connection between the temperature-sensitive resistance element 15A and the lead wires 15B and 15C, and prevent the temperature-sensitive resistance element 15A from being damaged by the stress.

The structure for absorbing stress due to thermal expansion and contraction is not limited to this, and for example, the terminal may be bent in a curved shape, and the lead wires on both sides of the temperature sensitive element 15 may be bent, It can be bent.

When the temperature-sensitive resistance element 15A is in contact with the inner surface of the housing 6, the heat received by the housing 6 is directly transferred to the temperature-sensitive resistance element 15A and further conducted from the lead wires 15B and 15C. Therefore, the response speed of the sealed thermosensitive device 10 is improved as compared with the conventional example, but when the sealed thermosensitive device 10 receives a force from the outside, both lead wires 15B,
15C and temperature sensitive resistance element 15A connection portion and each lead wire 1
Stress is applied to the connection between 5B and 15C and the respective metal cylinders. However, the stress applied to the connecting portion can be reduced by bending the lead wires 15B and 15C, and the temperature sensitive resistance element 15A can be prevented from being broken by the stress.

Next, FIG. 8 shows a third embodiment of the present invention.
In this embodiment, the same parts as those in the previous embodiment are designated by the same reference numerals and detailed description thereof will be omitted. The temperature-sensitive electric wire device 20 of the present invention is configured by connecting the shielded cable and the sealed heat-sensitive device 1. In the shielded cable used in this embodiment, as shown in FIG.
The structure is such that it is covered with 2, and then the conductor 23 and the insulating jacket 24 are covered in this order from the top. The center conductor 21 is conductively connected and fixed to the second metal cylinder 3 by welding or soldering, and the conductor 23 is conductively connected and fixed by welding or soldering so as to cover a part of the first metal cylinder 2. There is. The second metal cylinder 3 and the center conductor 21 are covered with an insulating film 25 to insulate the second metal cylinder 3 and the center conductor 21 from the conductor 23. By grounding the conductor 23, noise can be reduced even when the temperature-sensitive electric wire device 20 is installed in a place where electromagnetic waves are strong.
The sealed thermosensitive device 1 can accurately measure the resistance value corresponding to the temperature.

Further, although the center conductor of the shielded cable in this embodiment is a single core wire, a center conductor composed of metal wires intertwined with each other or a shielded cable having two center conductors can also be used. is there. When there are two central conductors, one of the central conductors is connected to the second metal cylinder 3 and the other is connected to the first metal cylinder 2, and the conductor 23 is connected to the first metal cylinder 2 and then the conductor 23 Noise can be reduced by grounding. In addition, the closed type heat sensitive device 1
It is needless to say that the closed type heat sensitive device 1 is used by being covered with an insulating film when the device is used while being insulated from other devices.

[0018]

As described above, the hermetically sealed thermosensitive device of the present invention is composed only of the housing made of two metal cylinders, the temperature sensitive resistance element, and the temperature sensitive element composed of the terminal. The number of parts is reduced and the structure of the device itself is simplified. Further, since the hermetically sealing work of the housing and the connection holding work of the temperature sensitive element can be simultaneously performed at both ends of the housing, the manufacturing work can be simplified and the work efficiency can be improved. Further, by providing a bent portion for absorbing stress to the terminal or bending the terminal, the stress generated by the difference in thermal expansion and contraction of each part of the heat-sensitive device generated within the operating temperature range of the heat-sensitive device Is elastically absorbed to prevent the temperature sensitive resistance element from being destroyed and impairing the function of the temperature sensitive element.

Further, the temperature-sensitive electric wire device of the present invention comprises a sealed heat-sensitive device and a shielded cable, in which the central conductor is connected to the second metal cylinder and the conductor is connected to the first metal cylinder. By grounding the conductor, noise can be reduced even when the temperature-sensitive electric wire device is installed in a place where electromagnetic waves are strong, and the sealed thermosensitive device can accurately measure the resistance value corresponding to temperature.

[Brief description of drawings]

FIG. 1 shows an embodiment of a sealed thermosensitive device of the present invention.

FIG. 2 shows an embodiment of the sealed thermosensitive device of the present invention.

FIG. 3 is a method for connecting a temperature-sensitive element of a sealed heat-sensitive device of the present invention.

FIG. 4 is a method for connecting a temperature-sensitive element of a sealed heat-sensitive device of the present invention.

FIG. 5 is a method for connecting a temperature-sensitive element of a sealed heat-sensitive device of the present invention.

FIG. 6 shows an embodiment of the sealed thermosensitive device of the present invention.

FIG. 7: Conventional sealed heat-sensitive device

FIG. 8: One embodiment of the sealed thermosensitive device of the present invention

[Explanation of symbols]

1, 10, 101: Closed type heat sensitive device 2: First metal cylinder 3: Second metal cylinder 4,105: Electrically insulating filler 5,15,106: temperature sensitive element 5A, 15A, 106A: temperature sensitive resistance element 5B, 5C, 15B, 15C, 106B: Lead wire 6: Housing 6A, 6B: housing end 7A, 7B: Welding electrode 8: Tube 15D: Bent part 20: Temperature sensitive wire device 21: Center conductor 22: Insulator 23: Conductor 24: Insulation skin 25: Insulating film 102: lid plate 103: Bottomed metal container 104: Lead terminal

Claims (3)

[Claims] 1. A housing in which a cylindrical second metal cylinder is airtightly fixed to one end of a cylindrical first metal cylinder with an electrically insulating filler, and a temperature-sensitive element whose electric resistance changes according to temperature. The second metal cylinder of the housing is thinner than the first metal cylinder and penetrates the filling material, and the temperature sensitive element is composed of a temperature sensitive resistance element and a lead wire connected to the temperature sensitive resistance element. This temperature sensitive element is housed in a housing, and the housing constitutes a hermetically sealed container by sealing both ends.When the housing is sealed, the lead wires of the temperature sensitive element are placed in the sealed portion. A hermetically sealed thermosensitive device characterized in that the sealing work and the fixing of the temperature sensitive element are performed simultaneously by connecting and fixing the lead wire of the temperature sensitive element to each metal cylinder together with the sealing of the housing. 2. The temperature sensing element as a whole is formed in a shape other than a straight line so that the function of the temperature sensing resistive element is not impaired by the stress applied to each part of the housing and the temperature sensing element.
The sealed heat-sensitive device according to. 3. A shielded cable in which a central conductor is covered with a metal conductor and the sealed thermosensitive device according to claim 1 or 2, wherein the central conductor is connected to a second metal cylinder of the sealed thermosensitive device, A temperature-sensitive electric wire device characterized in that noise can be reduced by connecting a body to a first metal cylinder of a sealed heat-sensitive device and grounding a conductor.