Compressor and refrigeration cycle

Abstract

This compressor is provided with a terminal protector (40) that stops power supply to a motor (5) when the temperature in the vicinity of a conductive pin (13) becomes equal to or higher than a set temperature set lower than the melting temperature of a glass member (14), and maintains the power supply stop state to the motor (5) even when the temperature becomes equal to or lower than the minimum temperature of the discharge temperature in the operation range of a compression mechanism (4). As a result, even when the motor generates heat due to motor lock, the conductive pin (13) can be prevented from falling off.

Description

Compressor and Refrigeration Cycle

[0001] The present invention relates to a compressor and a refrigeration cycle in which a compression mechanism for compressing a refrigerant and a motor for driving the compression mechanism are housed inside a sealed container, and a terminal for supplying power to the motor is provided on the sealed container.

[0002] In the compressor disclosed in Patent Document 1, the conductive pins of the terminals are fixed to the terminal body in an insulated manner by a glass member.

[0003] International Publication No. 2021 / 001921

[0004] In Patent Document 1, wear debris generated in the sliding parts of the compression mechanism circulates inside the compressor together with the refrigerant and may adhere to the glass members. The adhesion of wear debris to the glass members may cause short circuits between the conductive pins, melt the glass members, and cause the conductive pins to fall off.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a compressor and a refrigeration cycle that can prevent the conductive pins from falling off due to the melting of the glass member.

[0006] A compressor according to a first aspect of the present invention includes a compression mechanism 4 for compressing a refrigerant and a motor 5 for driving the compression mechanism 4, both housed within a sealed container 1. The sealed container 1 is provided with a terminal 10 for supplying power to the motor 5. The terminal 10 includes a terminal body 12, a conductive pin 13 for connecting a lead wire 11 from the motor 5, and a glass member 14 for insulating and fixing the conductive pin 13 to the terminal body 12. The compressor operates the motor 5 at a constant speed and is further provided with a terminal protector 40 that stops power supply to the motor 5 when the temperature near the conductive pin 13 reaches or exceeds a set temperature that is lower than the melting temperature of the glass member 14 and continues to stop power supply to the motor 5 even when the temperature falls below the minimum discharge temperature in the operating range of the compression mechanism 4. The compressor according to a second aspect of the present invention is characterized in that the set temperature is set higher than the discharge temperature. The compressor according to a third aspect of the present invention is characterized in that the terminal protector 40 is operated by a bimetal 41. The present invention according to claim 4 is characterized in that the terminal protector 40 operates by melting solder. The present invention according to claim 5 is characterized in that the terminal protector 40 is fixed to the sealed container 1 with at least two bolts 31. The present invention according to claim 6 is characterized in that the compressor according to claim 1 further includes a motor protector 20 that stops power supply to the motor 5 when the current value flowing through the lead wire 11 exceeds a set current value. The present invention according to claim 7 is characterized in that the refrigerant contains a flammable refrigerant, and the terminal protector 40 and the motor protector 20 are installed in an area where the refrigerant does not form a flammable region. The present invention according to claim 8 is characterized in that the motor protector 20 is installed inside the sealed container 1. The present invention according to claim 9 is characterized in that the refrigerant is a flammable refrigerant, and the terminal protector 40 is installed on the outer surface of the sealed container 1 and covered with a protective cover 30.The present invention of claim 10 is the compressor of claim 6, wherein the refrigerant is a flammable refrigerant, and the terminal protector 40 and the motor protector 20 are installed on the outer surface of the sealed container 1, and the terminal protector 40 and the motor protector 20 are covered with a protective cover 30. The present invention of claim 11 is the compressor of claim 9 or claim 10, wherein a first elastic member 32 is disposed between the protective cover 30 and the outer surface of the sealed container 1, and a second elastic member 33 is provided to press the terminal protector 40 against the outer surface of the sealed container 1. The present invention of claim 12 is the compressor of claims 1 to 10, wherein the refrigerant is R290. The present invention of claim 13 is a compressor equipped with a compressor of claims 1 to 10.

[0007] According to the present invention, if wear powder adheres to the glass member and causes a short circuit between the conductive pins, or if the motor locks and generates heat, power supply to the motor is stopped before the glass member reaches its melting temperature, thereby preventing the conductive pin from falling off.In addition, since power supply to the motor remains stopped even when the temperature drops below the minimum discharge temperature in the operating range of the compression mechanism, it is possible to reliably prevent the glass member from reaching its melting temperature and causing the conductive pin to fall off.

[0008] 1 is a cross-sectional view of a compressor according to one embodiment of the present invention; FIG. 2 is a view taken along the line A-A in FIG. 1; FIG. 3 is a view taken along the line E-E in FIG. 4;

[0009] A compressor according to a first embodiment of the present invention is provided with a terminal protector that stops power supply to the motor when the temperature near the conductive pin reaches or exceeds a set temperature that is lower than the melting temperature of the glass member, and that continues to stop power supply to the motor even when the temperature falls below the minimum discharge temperature in the operating range of the compression mechanism. According to this embodiment, if a short circuit occurs between the conductive pins due to wear powder adhering to the glass member, or if the motor locks and generates heat, power supply to the motor is stopped before the glass member reaches the melting temperature, thereby preventing the conductive pin from falling off. Furthermore, since power supply to the motor is continued to be stopped even when the temperature falls below the minimum discharge temperature in the operating range of the compression mechanism, it is possible to reliably prevent the glass member from reaching the melting temperature and causing the conductive pin to fall off.

[0010] In the second embodiment of the present invention, the set temperature is set higher than the discharge temperature in the compressor according to the first embodiment, so that the normal operation of the compression mechanism is not hindered.

[0011] In the third embodiment of the present invention, the terminal protector in the compressor according to the first embodiment is operated by a bimetal. According to this embodiment, the terminal protector has a simple structure and is highly reliable in operation.

[0012] In a fourth embodiment of the present invention, the terminal protector in the compressor according to the first embodiment is activated by melting of solder. According to this embodiment, the terminal protector can be constructed inexpensively.

[0013] In a fifth embodiment of the present invention, in the compressor according to the first embodiment, the terminal protector is fixed to the sealed container with at least two bolts. According to this embodiment, the terminal protector can be reliably fixed to the sealed container, so that the temperature near the conductive pin can be accurately transmitted to the terminal protector.

[0014] In the sixth embodiment of the present invention, the compressor according to the first embodiment is provided with a motor protector that stops the supply of power to the motor when the current value flowing through the lead wires exceeds a set current value. According to this embodiment, the motor protector stops the supply of power in response to an overcurrent, thereby improving the reliability of compressor protection.

[0015] In a seventh embodiment of the present invention, in the compressor according to the sixth embodiment, the refrigerant contains a flammable refrigerant, and the terminal protector and the motor protector are installed in an area where the refrigerant does not form a flammable region. According to this embodiment, even if a spark occurs in the terminal protector or the motor protector, the refrigerant can be prevented from burning.

[0016] In the eighth embodiment of the present invention, in the compressor according to the sixth embodiment, the refrigerant contains a flammable refrigerant, and the motor protector is installed inside the sealed container. According to this embodiment, the compressor can be made smaller.

[0017] In a ninth embodiment of the present invention, in the compressor according to the first embodiment, the refrigerant contains a flammable refrigerant, and the terminal protector is installed on the outer surface of the sealed container and covered with a protective cover. According to this embodiment, the terminal protector can be retrofitted to the sealed container, and even if a spark occurs at the terminal protector, combustion of the refrigerant can be prevented.

[0018] A compressor according to a tenth embodiment of the present invention is the compressor according to the sixth embodiment, except that the refrigerant contains a flammable refrigerant, and the terminal protector and motor protector are installed on the outer surface of the sealed container and covered with a protective cover. According to this embodiment, the terminal protector and motor protector do not require high cleanliness compared to when they are installed inside the sealed container, and therefore can be installed at low cost.

[0019] A compressor according to an eleventh embodiment of the present invention is the compressor according to the ninth or tenth embodiment, further comprising a first elastic member disposed between the protective cover and the outer surface of the sealed container, and a second elastic member that presses the terminal protector against the outer surface of the sealed container. According to this embodiment, the first elastic member can improve the sealing performance of the protective cover to the sealed container, and the second elastic member can improve the adhesion of the terminal protector to the sealed container.

[0020] A compressor according to a twelfth embodiment of the present invention is the compressor according to any one of the first to tenth embodiments, in which the refrigerant is R290. According to this embodiment, since the conductive pins can be reliably prevented from falling off, refrigerant leakage from the compressor does not occur, and safety is high even when R290 is used as the refrigerant.

[0021] A refrigeration cycle according to a thirteenth embodiment of the present invention is equipped with the compressor according to any one of the first to tenth embodiments. According to this embodiment, the compressor can reliably prevent the conductive pins from falling off, so that a highly reliable refrigeration cycle can be provided.

[0022] A compressor according to an embodiment of the present invention will now be described. FIG. 1 is a cross-sectional view of the compressor according to this embodiment. The compressor according to this embodiment is a two-piston rotary compressor. A suction pipe 2 for drawing in a refrigerant and a discharge pipe 3 for discharging the refrigerant are connected to a sealed container 1. Inside the sealed container 1, a compression mechanism 4 for compressing the refrigerant drawn through the suction pipe 2 and a motor 5 for driving the compression mechanism 4 are disposed. The bottom of the sealed container 1 forms an oil reservoir 6. A terminal 10 for supplying power to the motor 5 is provided on the top surface of the sealed container 1. The terminal 10 is covered with a protective cover 30. A motor protector 20 is provided inside the sealed container 1.

[0023] The compression mechanism 4 is composed of a cylinder 4a, a piston 4b, a vane (not shown), a main bearing 4c, and an auxiliary bearing 4d. The main bearing 4c is fixed to the sealed container 1. The piston 4b is rotatably fitted to an eccentric portion 7a of a rotating shaft 7 that passes through the cylinder 4a. The vane reciprocates in the vane groove following the piston 4b that rolls along the inner wall surface of the cylinder 4a. The main bearing 4c and the auxiliary bearing 4d seal the upper and lower end surfaces of the cylinder 4a and support the rotating shaft 7. The motor 5 is composed of a stator 5a fixed to the sealed container 1 and a rotor 5b arranged on the inner periphery of the stator 5a, and is driven at a constant speed.

[0024] Refrigerant is drawn into the compression mechanism 4 through the suction pipe 2 and compressed in the compression mechanism 4. The refrigerant then passes through the motor 5 and is discharged from the discharge pipe 3. The compressor of this embodiment is connected in a ring shape with a condenser, a pressure reducing device, and an evaporator through piping to form a refrigeration cycle. The condenser condenses the refrigerant discharged from the discharge pipe 3, the pressure reducing device reduces the pressure of the condensed refrigerant, and the evaporator evaporates the refrigerant reduced in pressure by the pressure reducing device. The refrigerant evaporated in the evaporator is returned to the compression mechanism 4 through the suction pipe 2 via the accumulator 8. Refrigerants containing flammable refrigerants can be used. The flammable refrigerants in this embodiment are mildly flammable refrigerants of Class 2L, flammable refrigerants of Class 2, and highly flammable refrigerants of Class 3 according to ISO 817 (2014), and are refrigerants that exhibit flame propagation at 101.3 kPa and 60°C. This embodiment is particularly suitable for compressors that use highly flammable refrigerants of Class 3, such as propane (R290), butane, and isobutane.

[0025] 2 is a view taken along the line A-A in FIG. 1. The terminal 10 has a terminal body 12, a conductive pin 13 to which the lead wire 11 from the motor 5 is connected, and a glass member 14 to insulate and fix the conductive pin 13 to the terminal body 12. The motor protector 20 is provided in proximity to the terminal 10. The motor protector 20 is connected in series with the lead wire 11 that is connected to the conductive pin 13, which serves as a common terminal, and has a thermostat. When the current value flowing through the lead wire 11 that supplies power to the motor 5 exceeds a set current value, the thermostat of the motor protector 20 activates and stops the supply of power from the lead wire 11 to the motor 5.

[0026] In this way, by stopping the power supply in response to an overcurrent using the motor protector 20, the reliability of compressor protection can be improved. Furthermore, by installing the motor protector 20 inside the sealed container 1, the compressor can be made smaller. Furthermore, since the inside of the sealed container 1 is an area where no flammable region is formed due to the refrigerant, a flammable refrigerant, particularly R290, is used as the refrigerant, and even if a spark occurs in the motor protector 20, combustion of the refrigerant can be prevented.

[0027] 3A and 3B are diagrams showing the main components of the compressor according to the present embodiment, with Fig. 3A being a view taken along the line B-B in Fig. 1, Fig. 3B being a view taken along the line C-C in Fig. 3A, and Fig. 3C being a view taken along the line D-D in Fig. 3A. As shown in Fig. 3, a terminal protector 40 is installed on the outer surface of the sealed container 1. The terminal protector 40, together with the terminal 10, is covered by a protective cover 30 on the top surface of the sealed container 1. Wiring from an external power source is connected to the terminal 10 via the terminal protector 40. The terminal 10 and the motor 5 are connected by lead wires 11 via a motor protector 20.

[0028] The terminal protector 40 is connected in series to the lead wire 11, which is connected to the conductive pin 13, which serves as a common terminal, and is operated by a bimetal 41. The bimetal 41 is made of a plate-shaped material made by bonding two or more metals or alloys with different thermal expansion coefficients together, and it bends in response to temperature changes. As temperature rises, the metal with the larger thermal expansion coefficient expands more, so it bends toward the metal with the smaller thermal expansion coefficient. This displacement of the bimetal 41 opens and closes the contacts, and opening the contacts stops the supply of power to the motor 5. The terminal protector 40 stops the supply of power to the motor 5 when the temperature near the conductive pin 13 exceeds a set temperature that is lower than the melting temperature of the glass member 14, and continues to stop the supply of power to the motor 5 even when the temperature drops below the minimum discharge temperature within the operating range of the compression mechanism 4.

[0029] By providing such a terminal protector 40, if wear debris adheres to the glass member 14, causing a short circuit between the conductive pins 13, or if the motor 5 becomes hot due to motor lock, power supply to the motor 5 is stopped before the glass member 14 reaches its melting temperature, preventing the conductive pins 13 from falling off. Furthermore, power supply to the motor 5 remains stopped even when the temperature drops below the lowest discharge temperature in the operating range of the compression mechanism 4, reliably preventing the glass member 14 from reaching its melting temperature and causing the conductive pins 13 to fall off. The set temperature for stopping power supply to the motor 5 is preferably set higher than the discharge temperature, which ensures normal operation of the compression mechanism 4 is not hindered. Furthermore, the terminal protector 40 operates using a bimetal 41, thereby improving operational reliability with a simple structure. Furthermore, by using solder melting instead of a bimetal 41, the terminal protector 40 can be constructed inexpensively.

[0030] The protective cover 30 is fixed to the top surface of the sealed container 1 with at least two bolts 31. A first elastic member 32 is provided between the protective cover 30 and the outer surface of the sealed container 1. The terminal protector 40 is pressed against the outer surface of the sealed container 1 by a second elastic member 33. The first elastic member 32 is suitably made of a resin material, particularly a rubber material, but may also be made of a silicone material or a metal packing. The second elastic member 33 is suitably made of a resin material, particularly a rubber material, but may also be made of a metal spring.

[0031] Therefore, the first elastic member 32 improves the sealing performance of the protective cover 30 on the sealed container 1, and the second elastic member 33 improves the adhesion of the terminal protector 40 to the sealed container 1. Furthermore, since the terminal protector 40 is fixed to the sealed container 1 with at least two bolts 31, the terminal protector 40 can be reliably fixed to the sealed container 1 and the temperature near the conductive pin 13 can be accurately transmitted to the terminal protector 40. Furthermore, by installing the terminal protector 40 on the outer surface of the sealed container 1 and covering the terminal protector 40 with the protective cover 30, the terminal protector 40 can be retrofitted to the sealed container 1. Furthermore, since the interior of the protective cover 30 is an area where a flammable region due to the refrigerant is not formed, even if a flammable refrigerant, particularly R290, is used as the refrigerant, combustion of the refrigerant can be prevented even if a spark occurs at the terminal 10 or the terminal protector 40.

[0032] According to this embodiment, even if the refrigerant contains a flammable refrigerant, particularly R290, the terminal protector 40 and the motor protector 20 are installed in an area where the refrigerant does not form a flammable region, so that the refrigerant can be prevented from burning even if a spark occurs in the terminal protector 40 or the motor protector 20. Furthermore, according to this embodiment, the conductive pin 13 can be reliably prevented from falling off, so that refrigerant leakage from the compressor does not occur, and safety is high even when R290 is used as the refrigerant.

[0033] A compressor according to another embodiment of the present invention will now be described. Fig. 4 is a cross-sectional view of the compressor according to this embodiment of the present invention, and Fig. 5 is a view taken along the line E-E in Fig. 4. Note that the same components as those in the embodiment shown in Figs. 1 to 3 are designated by the same reference numerals and will not be described again. In this embodiment, a motor protector 20 is installed on the outer surface of a sealed container 1 together with a terminal protector 40. The other components are the same as those in the embodiment shown in Figs. 1 to 3, and although not shown, this embodiment also includes a first elastic member 32 and a second elastic member 33. The motor protector 20, along with the terminal 10 and the terminal protector 40, is covered by a protective cover 30 on the top surface of the sealed container 1.

[0034] In this embodiment as well, the reliability of compressor protection can be improved by stopping the supply of power in the event of an overcurrent using motor protector 20. Furthermore, in this embodiment as well, if wear debris adheres to glass member 14, causing a short circuit between conductive pins 13, or if motor 5 generates heat due to motor lock, providing terminal protector 40 stops the supply of power to motor 5 before glass member 14 reaches its melting temperature, thereby preventing conductive pin 13 from falling off. Furthermore, because the supply of power to motor 5 remains stopped even when the discharge temperature falls below the minimum temperature within the operating range of compression mechanism 4, it is possible to reliably prevent glass member 14 from reaching its melting temperature and causing conductive pin 13 to fall off.

[0035] In this embodiment, the terminal protector 40 and the motor protector 20 are installed on the exterior of the sealed container 1 and covered with the protective cover 30. This reduces the need for high cleanliness compared to installing the terminal protector 40 and the motor protector 20 inside the sealed container 1, allowing for lower installation costs. Because the interior of the protective cover 30 is an area where a flammable refrigerant, particularly R290, is not formed, combustion of the refrigerant is prevented even if a spark occurs at the terminal 10, the terminal protector 40, or the motor protector 20. Furthermore, this embodiment reliably prevents the conductive pin 13 from falling off, preventing refrigerant leakage from the compressor and ensuring high safety even when R290 is used as the refrigerant. While the above embodiment uses a rotary compressor, the compressor may be any type, such as a scroll compressor, a reciprocating compressor, a screw compressor, or a swash plate compressor.

[0036] The compressor of the present invention is useful for devices such as dehumidifiers, indoor air conditioners, vehicle air conditioners, washing machines / dryers, refrigerators, water heaters, hot water heating systems, showcases, chillers, and freezers.

[0037] REFERENCE SIGNS LIST 1 sealed container 2 suction pipe 3 discharge pipe 4 compression mechanism 4a cylinder 4b piston 4c main bearing 4d auxiliary bearing 5 motor 5a stator 5b rotor 6 oil reservoir 7 rotating shaft 7a eccentric portion 8 accumulator 10 terminal 11 lead wire 12 terminal body 13 conductive pin 14 glass member 20 motor protector 30 protective cover 31 bolt 32 first elastic member 33 second elastic member 40 terminal protector 41 bimetal

Claims

1. A compressor having a compression mechanism for compressing a refrigerant and a motor for driving the compression mechanism inside a sealed container, a terminal for supplying power to the motor provided in the sealed container, the terminal having a terminal body, a conductive pin for connecting a lead wire from the motor, and a glass member for insulating and fixing the conductive pin to the terminal body, and operating the motor at a constant speed, characterized in that the compressor is provided with a terminal protector that stops supplying power to the motor when the temperature in the vicinity of the conductive pin reaches or exceeds a set temperature that is set lower than the melting temperature of the glass member, and that continues to stop supplying power to the motor even if the discharge temperature falls below the minimum temperature in the operating range of the compression mechanism.

2. The compressor according to claim 1, wherein the set temperature is set higher than the discharge temperature.

3. The compressor according to claim 1, characterized in that the terminal protector is operated by a bimetal.

4. The compressor according to claim 1, characterized in that the terminal protector operates by melting of solder.

5. The compressor according to claim 1, characterized in that the terminal protector is fixed to the sealed container by at least two bolts.

6. The compressor according to claim 1, further comprising a motor protector that cuts off the supply of power to the motor when the current flowing through the lead wires reaches or exceeds a set current value.

7. The compressor according to claim 6, characterized in that the refrigerant contains a flammable refrigerant, and the terminal protector and the motor protector are installed in an area where no flammable area is formed by the refrigerant.

8. The compressor according to claim 6, characterized in that the refrigerant contains a flammable refrigerant, and the motor protector is installed inside the sealed container.

9. The compressor according to claim 1, characterized in that the refrigerant contains a flammable refrigerant, the terminal protector is installed on the outer surface of the sealed container, and the terminal protector is covered with a protective cover.

10. The compressor according to claim 6, characterized in that the refrigerant contains a flammable refrigerant, the terminal protector and the motor protector are installed on the outer surface of the sealed container, and the terminal protector and the motor protector are covered with a protective cover.

11. The compressor according to claim 9 or 10, characterized in that it is provided with: a first elastic member disposed between the protective cover and the outer surface of the sealed container; and a second elastic member that presses the terminal protector against the outer surface of the sealed container.

12. A compressor according to any one of claims 1 to 10, characterized in that the refrigerant is R290.

13. A refrigeration cycle comprising a compressor according to any one of claims 1 to 10.

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