JP2000180266A - Heat sensitive sensor and hermetic motor-driven compressor fitted therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sensitive sensor easy to manufacture, and especially suitable for the control of a motor-driven compressor such as that used for an air-conditioner. SOLUTION: This heat sensitive sensor 1 comprises a base consisting of an electric insulating base part 2A an a cap 2B, two terminals 3A, 3B fixed to this base, and a thermistor 4 connected to each one end of the respective terminals. The thermistor 4 is positioned so as to elastically abut on the positioning part 2B3 of the base. The thermsitor is positioned by abutting the thermistor body on the base, and the shaking of the thermistor due to vibration is restrained to prevent the falling-off and breakage of the fixing part. Since the thermistor body is not fixed to the base, the glass coating or the like to the thermistor body is not broken by the strain or the stress due to the difference in the expansion/contraction coefficient of the material caused by the ambient temperature change.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal sensor, and more particularly to a thermal sensor suitable for controlling an electric compressor such as an air conditioner.

[0002]

2. Description of the Related Art Conventionally, as a thermal sensor used for an electric compressor of an air conditioner, there is a thermal sensor that detects abnormal overheating with a bimetal or the like and drives a contact with the bimetal to interrupt an electric circuit. Such a so-called thermal protector protects the motor by passing the operating current of the motor through the bimetal, and even when an abnormal current flows, the bimetal rises in temperature to the operating temperature due to Joule heat and immediately shuts off the current. can do.

[0003] In recent years, the number of electric compressors for air conditioners in which the operating state of the electric compressor is controlled by an inverter has been increasing. According to this inverter-controlled air conditioner, the operating capability of the air conditioner can be finely controlled by controlling the rotation speed of the electric motor in accordance with conditions such as room temperature. However, since the effective value of the energizing current fluctuates greatly in order to change the rotation speed of the motor, it is difficult to use the conventional type in which protection is performed by the ambient temperature and the energizing current. In addition, in order to control with an inverter, it is necessary to know the temperature change in the electric compressor precisely, and the conventional contact type thermal protector cannot detect and output a continuous change, so that it cannot be used in this regard.

[0004]

In inverter control, a thermistor or the like that continuously changes the output value with respect to a temperature change is used as a thermal sensor. As a device using such a thermal sensor, there is, for example, an "electric machine protection device" disclosed in Japanese Patent Application Laid-Open No. 61-142942. In this protection device, the temperature sensor is placed between the windings of the motor,
An insulating tape-shaped material is arranged as a container. However, in this example, the container is composed of a thin tape-shaped material so as to be sandwiched between the windings of the electric motor, but to fix it at other positions, the container has no rigidity, especially a thermistor sealed with glass. When used, the glass seal may be broken during handling.

On the other hand, the applicant has disclosed in Japanese Patent Application Laid-Open No. 7-27.
No. 621 proposes an "enclosed thermal device" in which a thermistor is housed in a metallic hermetic container.
According to this example, no direct force is applied to the thermistor in handling, but there is a problem that the response is slightly inferior to changes in the ambient temperature because the closed container is used.

Various proposals have been made, such as Japanese Utility Model Application Laid-Open No. 57-75541 and Japanese Utility Model Application Laid-Open No. 58-180436, in which a thermistor is attached to a terminal on a base. Is protected by a metal tube or a glass tube, the whole is resin-molded, or a thermistor is buried in a case with a filler, and the manufacturing is not easy.

[0007]

SUMMARY OF THE INVENTION Accordingly, a thermal sensor according to the present invention comprises an electrically insulating base, and a base fixed to the base.
And a thermistor connected to one end of each terminal.The thermistor abuts on a positioning portion provided on the base to define a distance from a predetermined surface of the base and to vibrate with the terminal by vibration. The stress applied to the fixing portion of the lead is reduced, an opening through which the surrounding atmosphere can flow is provided in the positioning portion of the thermistor, and the thermistor is protected from being touched from the outside, and the thermistor is directly exposed to the surrounding atmosphere by the opening. It is characterized by having such a configuration.

According to the present invention, since the thermistor is positioned on the base, the positional relationship of the thermistor with respect to the portion where the thermal sensor is mounted is automatically determined.
Also, since the thermistor is elastically held on the base,
Swaying of the thermistor due to vibration from the portion where the thermal sensor is mounted can be suppressed, and the falling off and destruction of the fixed portion can be reliably prevented.

Another feature is that a through hole is provided in the base, and a terminal is inserted into and fixed to the through hole, so that it is possible to cope with various terminal shapes with simple equipment.

Still another feature is that the base includes a base and a thermistor positioning portion, and the positioning portion is fixed to the base after the thermistor is fixed, so that the thermistor can be more securely covered. .

Another aspect of the present invention is a hermetic electric compressor to which the above-mentioned thermal sensor is attached, wherein the hermetic container is constituted by a bottomed cylindrical lower container and a lid plate welded to the upper end thereof.
An electric motor and a compressor main body driven by the electric motor are arranged in the hermetically sealed container. A through hole is provided in the hermetically sealed container, and a hermetically sealed terminal for supplying electric power to the electric motor is hermetically fixed. A suction pipe and a discharge pipe for circulating the heat to the heat exchanger are fixedly penetrated, and a thermal sensor is directly mounted on the compressor body.

Still another feature is that in the hermetic electric compressor, the compressor body is a scroll type compressor, and a heat-sensitive sensor is attached to a fixed scroll side.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 and 3 are external views from the front and side of the present invention, FIGS. 2 and 4 are cross-sectional views of each, and FIG. 5 is a cross-sectional view taken along the line AA of FIG. FIG. 6 is a perspective view showing a state in which a cap as a positioning member is removed.

The thermal sensor 1 has a resin base 2A, which is an electric insulator, and a resin cap 2B for positioning a thermistor, which will be described later, and both are fixed to form a sensor base. The base 2A is provided with two through holes for terminals, and the terminals 3A and 3B are fixed through the respective through holes. In the embodiment, the terminal is fixed with a filler after being inserted into the through hole, but may be fixed in advance integrally with the base by insert molding. As long as the terminal is inserted and fixed in the through hole provided in the base as in this embodiment, the shape of the other end of the terminal may be different as long as the shape of the inserted portion is the same, so that it is simple. It can respond to various terminal shapes with simple equipment. Therefore, it is possible to easily cope with various terminal shapes such as a case where a lead wire is fixed to an end portion of a terminal by welding and a case where a lead wire is connected using a receptacle or a tab.

When the terminals are fixed to the bases by filling material or insert molding, holes 3A1, 3A2, 3A2, 3A2 of the terminals 3A, 3B are formed in portions of the terminals 3A, 3B embedded in the base 2A.
When the filler or resin flows into 3B1 (not shown) and 3B2, the terminals are prevented from coming off. Further, in the embodiment, at a position away from the mounting portion of the terminal on the base 2A,
A mounting hole 2C used for fixing the sensor 1 is provided. Partitions 2D and 2E are provided between the two through holes to ensure electrical insulation between the terminals 3A and 3B.

The leads 4A and 4B of the thermistor 4 are fixed to one ends of the terminals 3A and 3B by spot welding or the like. A groove 2F is provided around the terminal mounting portion of the base 2A and the partition wall. After the thermistor 4 is mounted, the cap 2B is mounted so as to cover the thermistor 4, and the two are ultrasonically welded together in accordance with the groove 2F. Fix it. In the embodiment, the cap 2B has a substantially cylindrical shape on the side where the cap is fixed to the base, and the side for storing the thermistor 4 is narrowed down in accordance with the mounting shape of the thermistor, and the surface facing the thermistor is wider than the thermistor 4. Narrow opening 2B1
However, a slit-shaped opening 2B2 is provided near the tip.

The cap 2B is located on the inner positioning portion 2B.
The thermistor 4 elastically contacts the base 3 to determine the position of the thermistor with respect to a predetermined surface of the base, in this embodiment, the mounting surface 2A1, and to suppress the thermistor from oscillating due to vibration transmitted from the portion where the thermal sensor is mounted. The destruction of the fixed portion between the leads 4A, 4B and the terminals 3A, 3B can be prevented. Also, since the thermistor is only elastically abutted and positioned and is not fixed to the cap 2B, there is a difference in the expansion and contraction rate due to the difference in the respective materials such as metal and resin or glass due to changes in the ambient temperature. However, since it does not receive strain or stress directly and can be absorbed by the lead, there is almost no influence on the glass coating of the fragile thermistor body.
Further, by covering the thermistor 4 with the cap 2B, a direct force is not applied to the thermistor when the thermal sensor 1 is handled, so that damage is prevented. Especially cap 2B
Is formed separately from the base 2A, the cap does not hinder the work when the thermistor 4 is mounted, and the thermistor can be reliably protected after the cap is mounted. In addition, by disposing the thermistor on a resin base, for example, when the fixed scroll of the refrigerant compressor is set as a detection target and the thermal sensor is mounted on the metal part, the thermistor is compared with directly mounting the thermistor. The transmission of vibrations to the object is alleviated by passing through the resin base, and the work of determining the positional relationship between the object to be detected and the thermistor in mounting is also facilitated.

Next, an example in which the thermal sensor 1 is attached to an electric compressor will be described with reference to FIG. FIG.
1 is a cross-sectional view of a hermetic electric compressor used for a room air conditioner and the like, and an embodiment using a scroll-type hermetic electric compressor will be described in the embodiment. As the hermetic electric compressor, a compressor other than the scroll type may be used, but the scroll type is particularly advantageous since the vibration applied to the sensor is small because the vibration is small. Although the lower part of the hermetic electric compressor 11 is omitted, a lower cylindrical metal container 12 having a bottom and a metal cover plate 13 are omitted.
, And a lid plate is hermetically welded and fixed to the upper end opening of the lower container to form a closed container.

An electric motor 14 and a scroll compressor 15 driven by the electric motor are provided in the closed container. The scroll type compressor 15 has a movable scroll 15.
A and a fixed scroll 15B.
5A is connected to a rotor 14A of the electric motor 14 via a drive section 16A eccentric to the drive shaft 16.

In the embodiment, an airtight terminal 17 having a conductive terminal for connecting an electric motor to an external power supply, and a suction pipe 18 for sucking refrigerant gas are passed through the lower container 12 and fixed in an airtight manner. I have. The cover plate 13 has a second hermetic terminal 19 for transmitting a sensor signal to the outside and a discharge pipe 20 for discharging the refrigerant gas compressed by the compressor to the outside. It is fixed to.

The fixed scroll 15B is provided with a non-penetrating mounting hole in which the thermal sensor 1 is fixed by fixing means such as bolts. Thus, the positional relationship between the thermistor 4 positioned in the thermal sensor 1 and the fixed scroll 15B is automatically determined. In the embodiment, the temperature of the fixed scroll 15B can be quickly detected by fixing the thermistor 4, which is a heat-sensitive portion of the heat-sensitive sensor, so as to fit in the mounting hole. If necessary, the surrounding atmosphere such as a refrigerant can be more positively circulated in the mounting hole by expanding the mounting hole or providing a passage.

The thermal sensor 1 is connected to a control device (not shown) outside the sealed container via an airtight terminal 19.
This control device monitors the temperature of the fixed scroll 15B by measuring the resistance value of the thermistor 4. Therefore, if the fixed scroll 15B becomes excessively hot due to, for example, a decrease in the cooling function due to leakage of the refrigerant gas or overheating of the refrigerant gas due to the heat generated by the electric motor, the fixed scroll 15B is attached from the opening when the fixed scroll is abnormally overheated due to some problem. Heat is transmitted to the thermistor 4 via the ambient atmosphere in the hole, and the control device that detects abnormal overheating from the change in the resistance value of the thermistor shuts off the power supply to the motor.

In particular, since the thermistor is positioned on the base of the thermal sensor, the positional relationship of the thermistor with respect to a compressor or the like to which the thermal sensor is attached is automatically determined, so that there is no variation in sensitivity between mountings.
When abnormal overheating occurs, burning and destruction of the electric motor and the compressor can be reliably prevented. In addition, by attaching the heat sensor to the fixed scroll of the scroll compressor, the influence of vibration from the compressor on the heat sensor can be further reduced.

Next, another embodiment of the thermal sensor will be described with reference to FIGS. FIG. 8 is a plan view showing a partial cross section of the thermal sensor of the present embodiment. FIG. 9 is a cross-sectional view of the thermal sensor of FIG. This thermal sensor 3
1 has a base 32 made of resin. The base 32 has a holding portion for inserting and holding each of the two terminals 33A and 33B. The terminals 33A and 33B are fixed to the base 32 by an appropriate method as in the above-described example, and the thermistors 34 are fixed to the ends 33A1 and 33B1 of the respective terminals by welding the leads 34A and 34B. . The thermistor 34 is disposed in the thermistor storage portion 32A of the base 32. The storage portion 32A covers the outer periphery of the thermistor with a wall 32B and is opened on both sides of the base. By circulating the ambient atmosphere around the thermistor, heat exchange is improved and the thermistor can be directly used in normal handling. Protect from touch.
In addition, the housing portion 32A is opened on both sides, and one end of the terminal 33A, 33B is provided at the opened position, so that welding of the terminals 33A, 33B and the leads 34A, 34B becomes easy. Although not shown in the figure, lead wires to be described later are connected and fixed to the other ends 33A2 and 33B2 of the terminals.

Further, a thermistor positioning portion 32C whose opening width becomes narrower in the opposite direction from the thermistor mounting side is provided at the center of the opening of the storage portion 32A, and the thermistor 34 is held in contact with the inner wall thereof. Here, since the thermistor 34 is constantly biased so as to be pressed against the inner wall of the positioning portion, the positional relationship with respect to the mounting surface 32E of the base 32 is determined, so that a predetermined mounting location, in the embodiment, a fixed scroll 45B as described later. When the thermal sensor 31 is attached to the device, the positional relationship between the attachment surface and the thermistor is automatically determined. Also, even if vibration is transmitted from the portion where the thermal sensor 31 is attached, the deflection of the thermistor can be suppressed, so that the leads 34A and 34B and the terminal 33
It is possible to prevent the destruction and drop-off of the fixed portion with A and 33B and the breakage of the lead and the glass seal. A mounting hole 32D is provided substantially at the center of the base 32, and a mounting surface 32E faces the fixed scroll when mounted on the scroll compressor, and a mounting screw is inserted into the mounting hole 32D to provide a predetermined hole provided on the fixed scroll. The thermal sensor 31 is fixed by being screwed into the mounting position. Thus, the thermal sensor 31
Is fixed, the thermistor 34 positioned with respect to the base 32 also determines the positional relationship with respect to a heat generating place such as a fixed scroll, so that the work of adjusting the mounting position for each product can be reliably omitted.

Next, the case where this thermal sensor is used in a hermetic electric compressor will be described with reference to FIG. Note that the electric compressor 41 itself is the same as that shown in FIG. 7 described above. The electric compressor 41 accommodates a scroll compressor 45 in a closed container, and includes a fixed scroll 45B.
Is fixed with a thermal sensor 31. The thermal sensor 31 of the embodiment has a fixed scroll 45 as a detection target.
The surface on which the thermistor is mounted is the mounting surface 32E directly facing the fixed scroll so that the thermistor 34 can more easily receive heat from B. For example, when the temperature of the refrigerant flowing around is to be detected. It goes without saying that the mounting surface of the thermistor may be turned upside down.

The above-mentioned thermal sensors 1 and 31 detect the temperature of the fixed scroll of the hermetic electric compressor 11 or 41, which is the device to be controlled, or the temperature of the refrigerant flowing in the hermetic container and detect the resistance corresponding to the detected temperature. Value. Accordingly, a control device (not shown) connected to the heat sensor via the second hermetic terminal 19 can cut off the power supply to the electric motor when the inside of the closed container becomes abnormally overheated.

[0028]

As described above, according to the present invention, the position of the thermistor is determined by the elastic contact of the thermistor body on the base, and the thermistor swings due to vibration from the portion where the thermal sensor is mounted. And the falling off and destruction of the fixed portion can be prevented. In addition, since the thermistor body is not fixed to the base, the thermistor body is held elastically by the leads even if there is a difference in the expansion and contraction rate of the material due to changes in the ambient temperature. Is absorbed by the lead, so that there is almost no effect on the glass coating of the fragile thermistor body.

Further, by covering the thermistor with the base, a force is not directly applied to the thermistor at the time of handling the thermal sensor or the like, thereby preventing the thermistor from being damaged. In addition, the positioning of the thermistor on the base facilitates the operation of determining the positional relationship between the object to be detected and the thermistor during mounting.

[Brief description of the drawings]

FIG. 1 is a front view showing one embodiment of a thermal sensor of the present invention.

FIG. 2 is a sectional view of the thermal sensor of FIG. 1;

FIG. 3 is a side view of the thermal sensor of FIG. 1;

FIG. 4 is a sectional view of the thermal sensor of FIG. 3;

FIG. 5 is a sectional view of the thermal sensor of FIG.

FIG. 6 is a perspective view showing a state where a cap of the thermal sensor of FIG. 1 is removed.

FIG. 7 is a sectional view showing an embodiment of the hermetic electric compressor of the present invention.

FIG. 8 is a partial sectional view showing another embodiment of the thermal sensor of the present invention.

9 is a cross-sectional view of the thermal sensor of FIG.

FIG. 10 is a sectional view showing another embodiment of the hermetic electric compressor of the present invention.

[Explanation of symbols]

 1, 31: Thermal sensor 2A: Base 2B: Cap 2B3, 32C: Positioning part 3A, 3B, 33A, 33B: Terminal 4, 34: Thermistor 11, 41: Hermetic electric compressor 14: Electric motor 15, 45: Compressor 15B, 45B: Scroll for fixing 17, 19: Airtight terminal 32: Base

Continued on the front page (72) Inventor Hideki Koseki 4-30, Hoshocho, Minami-ku, Nagoya-shi

Claims (5)

[Claims] An electric insulating base, two terminals fixed to the base, and a thermistor connected to one end of each terminal. The thermistor contacts a positioning portion provided on the base. The distance from a predetermined surface of the base is defined by the contact, and the stress applied to the fixed portion between the terminal and the lead by vibration is reduced.The positioning portion of the thermistor is provided with an opening through which the surrounding atmosphere can flow, and the thermistor is provided. A thermal sensor, wherein the sensor is protected from being touched from the outside and the thermistor is directly exposed to the surrounding atmosphere by the opening. 2. The base according to claim 1, wherein a through hole is provided in the base, and the terminal is inserted and fixed in the through hole.
Thermal sensor according to 1. 3. The thermal sensor according to claim 1, wherein the base comprises a base and a thermistor positioning part, and the positioning part is fixed to the base after the thermistor is fixed. 4. A closed container is formed by a bottomed cylindrical lower container and a lid plate welded to the upper end thereof, and an electric motor and a compressor main body driven by the electric motor are arranged in the closed container. A through hole is provided in the container, a sealed terminal for supplying electric power to the electric motor is hermetically fixed, and a suction pipe and a discharge pipe for circulating the compressed refrigerant to the heat exchanger are fixed through the compressor body. 4. A hermetic electric compressor, wherein the thermal sensor according to claim 1 is directly mounted thereon. 5. The hermetic electric compressor according to claim 4, wherein the compressor body is a scroll type compressor, and the heat sensor is attached to a fixed scroll side.