JP6927911B2 - Refrigeration cycle equipment - Google Patents

Description

Embodiments of the present invention relate to refrigeration cycle equipment.

When the refrigeration cycle device is used in a low temperature environment, the refrigerant may liquefy and dissolve in the lubricating oil in the compressor before starting, which may cause a problem that the viscosity of the lubricating oil decreases.

Therefore, a method has been devised in which a band-shaped heater is provided on the lower outer peripheral surface of the airtight case of the compressor and heated before the start of operation to prevent poor lubrication at the time of starting.

Japanese Unexamined Patent Publication No. 2012-97638

However, in the above-mentioned conventional structure, the entire sealed case of the compressor is heated, which consumes extra power. In addition, the airtight case of a general compressor has a thickness of 3 to 4 mm, and it takes time for heat to be transferred to the lubricating oil.

An object to be solved by the present invention is to propose a refrigerating cycle apparatus capable of saving power and shortening the start-up time by efficiently heating the lubricating oil.

In order to solve the above problems, the refrigeration cycle apparatus according to the embodiment of the present invention includes a compressor, a radiator connected to the compressor, an expansion device, and a heat absorber, and the compressor is filled with a refrigerant and A closed case provided with an oil sump portion for storing lubricating oil at the bottom, a compression mechanism portion housed in the closed case for compressing the refrigerant, and the lubricating oil without operating the compression mechanism portion. It includes an oil circuit configured to circulate between the outside of the closed case and the inside of the closed case, and a heating means for heating the lubricating oil in the oil circuit.

It is a block diagram of the refrigeration cycle apparatus including the compressor shown in the cross section in this embodiment. It is a horizontal cross-sectional view which shows the compression mechanism part.

An embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 shows a refrigeration cycle device 1, which is a compressor 2, a condenser 3 which is a radiator connected to the compressor 2, and an expansion device 4 connected to the condenser 3. The evaporator 5 which is endothermic connected to the expansion device 4 and the accumulator 6 connected to the evaporator 5 are provided, and the accumulator 6 is connected to the compressor 2. In the compressor 2, the gas refrigerant as a working fluid is compressed to a high temperature and high pressure, and in the radiator 3, heat is dissipated from the high temperature and high pressure gas refrigerant and condensed. In the expansion device 4, the refrigerant is decompressed, and in the evaporator 5, the decompressed liquid refrigerant is vaporized to become a gas refrigerant. In the accumulator 6, the liquid refrigerant contained in the gas refrigerant is separated, and only the gas refrigerant is supplied to the compressor 2.

In this refrigeration cycle device 1, the refrigerant circulates while changing phase between a gas refrigerant and a liquid refrigerant, and heat dissipation and endothermic are performed in the process, and heating, cooling, and heating are performed by utilizing these heat dissipation and heat absorption. Cooling etc. are performed.

The compressor 2 has a closed case 7 which is formed in a substantially cylindrical shape and is in an airtight state, and a compression mechanism portion 8 which is a portion for compressing a gas refrigerant and the compression mechanism portion 8 are provided in the closed case 7. The electric motor unit 9 which is a driving portion is housed. The electric motor unit 9 is provided with a rotating shaft 10, and the compression mechanism unit 8 is driven by the electric motor unit 9 via the rotating shaft 10. Lubricating oil 11 is stored in the bottom of the sealed case 7.

The electric motor unit 9 has a rotor 12 fixed to the rotating shaft 10 and a stator 13 fixed to the inner peripheral surface of the sealed case 7 and arranged at a position surrounding the rotor 12. A permanent magnet (not shown) is provided on the rotor 12, and a coil for energization (not shown) is wound around the stator 13. The rotating shaft 10 is rotated around the center line by a main bearing 14 located between the motor portion 9 and the compression mechanism portion 8 and an auxiliary bearing 15 located on the opposite side of the main bearing 14 with the compression mechanism portion 8 interposed therebetween. It is bearing as possible.

The compression mechanism 8 includes a cylinder 16 having both ends opened in the vertical direction, a main bearing 14 serving as a closing member for closing the opening on the upper end side of the cylinder 16, and a closing portion for closing the opening on the lower end side of the cylinder 16. It has an auxiliary bearing 15 that also serves as a member, and a cylinder chamber 17 is provided inside the cylinder 16 by closing both ends of the cylinder 16 with the main bearing 14 and the auxiliary bearing 15. A rotary shaft 10 is inserted through the cylinder chamber 17, and an eccentric portion 18 is provided at a portion of the rotary shaft 10 located in the cylinder chamber 17. A roller 19 is fitted to the eccentric portion 18, and the roller 19 is provided so as to rotate eccentrically in the cylinder chamber 17 as the rotating shaft 10 rotates.

As shown in FIG. 2, the cylinder 16 is provided with a blade groove 20, and two blade members 21 and 22 are inserted into the blade groove 20 so as to be reciprocally movable. As shown in FIG. 1, the two blade members 21 and 22 are provided so as to be overlapped with each other in the axial direction of the rotating shaft 10, and the tip portions of the blade members 21 and 22 are in contact with the outer peripheral surface of the roller 19 so that the blade member 21 , A coil spring 23 for urging the blade members 21 and 22 is arranged on the rear end side of the 22.

The tip portions of the blade members 21 and 22 are brought into contact with the outer peripheral surface of the roller 19, so that the inside of the cylinder chamber 17 is divided into a suction chamber 24 and a compression chamber 25, as shown in FIG. Further, the cylinder 16 is provided with a suction passage 26 through which the gas refrigerant sucked into the suction chamber 24 flows.

Returning to FIG. 1, the main bearing 14 is provided with a discharge hole (not shown) for discharging the gas refrigerant compressed in the compression chamber 25. Further, the main bearing 14 is provided with a discharge valve 28 that opens and closes the discharge hole, and a discharge muffler 29 that covers the discharge hole and the discharge valve 28. The discharge muffler 29 is formed with a communication hole 30 that communicates the inside of the discharge muffler 29 and the inside of the closed case 7.

When the pressure of the compressed gas refrigerant reaches the set pressure, the discharge valve 28 is opened, and the compressed gas refrigerant is discharged into the discharge muffler 29 from the discharge hole (not shown). The high-pressure gas refrigerant discharged into the discharge muffler 29 passes through the communication hole 30 and flows into the closed case 7, and the inside of the closed case 7 is filled with the high-pressure gas refrigerant. The high-pressure gas refrigerant in the sealed case 7 circulates to the compressor 2 again via the endothermic device 3, the expansion device 4, and the evaporator 5, so that the refrigeration cycle is executed.

An oil circuit 41 is provided in the lower part of the sealed case 7. The oil circuit 41 is formed of a hollow pipe (piping) having a substantially U-shape in appearance, and vertically penetrates the side surface of the sealed case 7 at two places above and below so as to open into the lubricating oil 11 in the sealed case 7. It is configured in. That is, one end of the oil circuit 41 protrudes inward from the inner wall surface of the sealed case 7 to open into the lubricating oil 11, and the lower connection extends linearly through the side surface of the sealed case 7. Lubricating oil heat transfer part 41b and lubricating oil heat transfer part 41b that are bent upward by about 90 degrees in an L shape at the other end of the pipe 41a and the lower connecting pipe 41a and extend substantially parallel to the sealed case 7. An upper connecting pipe that is bent into an L-shape at approximately 90 degrees at the tip of the sealing case 7, vertically penetrates the side surface of the sealing case 7, protrudes inward from the inner wall surface of the sealing case 7, and opens below the oil level of the lubricating oil 11. It is composed of 41c.

By the way, the closed case 7 is filled with the suction refrigerant sucked into the compression mechanism unit 8 or the compression refrigerant discharged from the compression mechanism unit 8. When the operation is stopped, the temperature of the sealed case 7 gradually decreases, and the refrigerant filling the sealed case 8 tends to liquefy. The liquefied liquid refrigerant dissolves in the lubricating oil 11 stored in the oil sump 44, and the viscosity of the lubricating oil decreases. If the operation is started (started) in this state, the lubricating oil 11 having a low viscosity is supplied to the sliding portion, resulting in poor lubrication.

Therefore, a heating means 43 is provided in the vicinity of the lubricating oil heat transfer portion 41b of the oil circuit 41. This is because the lubricating oil 11 is heated to vaporize the liquefied refrigerant contained in the lubricating oil 11 before the compressor 2 is started. As the heating means 43, for example, a known ribbon heater or tape heater can be used, and the lubricating oil heat transfer portion 41b is directly heated by winding or attaching these to the outer peripheral surface of the lubricating oil heat transfer portion 41b. do. As a result, the heat is transferred to the lubricating oil 11 flowing through the oil circuit 41 to be heated. As a result, the refrigerant contained in the lubricating oil 11 of the oil sump portion 44 is vaporized, so that the viscosity of the lubricating oil 11 increases. As a result, when starting the compressor 2, lubricating oil having a predetermined viscosity can be supplied from the oil suction portion 45, and insufficient lubrication at the sliding portion can be prevented. Further, in the present embodiment, as compared with the conventional method of heating the entire case, the lubricating oil 11 can be efficiently heated, so that the warm-up operation can be shortened and power saving can be achieved.

Further, the heating means 43 is provided with a control means 46 for controlling its operation. When the start signal is input to the compressor 2, the control means 46 measures the temperature of the lubricating oil from the oil temperature sensor 47 provided in the lower part of the sealed case 7. When the temperature is equal to or lower than a predetermined value, the heating means 43 is energized to heat the lubricating oil 11. When the temperature of the lubricating oil 11 exceeds the set value, the energization of the heating means 43 is stopped and the compressor 2 is started. By doing so, the temperature of the lubricating oil 11 can always be kept normal, and the reliability and performance of the compressor 2 can be improved. Moreover, since it is heated only when necessary, energy saving can be achieved without wasting power.

The pipe forming the oil circuit 41 is made of copper, an aluminum alloy, or the like, which has a higher thermal conductivity than the steel material, which is the material of the sealed case 7. Therefore, since the pipe forming the oil circuit 41 has a better heat transfer coefficient than the closed case 7, the heat of the heating means 43 can be efficiently transferred to the lubricating oil 11 in the lubricating oil heat transfer section 41b. Further, the heat of the lubricating oil heat transfer portion 41b heated by the heating means 43 is transmitted to the upper connecting pipe 41c and the lower connecting pipe 41a of the oil circuit 41 and also to the oil pool portion 44 in the sealed case, which is more efficient. The lubricating oil 11 can be heated.

Further, a pump 42 is provided in the middle of the lower connecting pipe 41a as a circulation means for forcibly circulating the lubricating oil 11, whereby the lubricating oil 11 in the sealed case 7 is circulated in the oil circuit 41. NS. With this configuration, the lubricating oil 11 can be circulated without operating the compressor 2, and the refrigerant dissolved in the lubricating oil 11 of the oil sump portion 44 can be vaporized in a short time. can.

The pump 42 does not have to have an essential configuration. Even if the pump 42 is not used, the lubricating oil 11 heated by the heating means 43 in the lubricating oil heat transfer section 41b flows to the upper part of the oil sump section 44 by natural convection. As a result, the cold lubricating oil 11 in the oil sump 44 is pushed down downward and flows into the lower connecting pipe 41a. By using natural convection as a circulation means in this way, it is possible to circulate and heat the lubricating oil 11 without using the pump 42. In this case, since the pump 42 is not used, further power saving can be realized. When natural convection is used as the circulation means, the upper connecting pipe 41c needs to be above the lower connecting pipe 41a, and the upper connecting pipe 41c is below the oil level of the oil sump 44. There must be.

Further, in the present embodiment, the first control valve 51a is provided in the pipe connecting the expansion device 4 and the radiator 5, and the expansion device 4 and the first control valve 51a are bypassed so as to bypass the first control valve 51a. A bypass circuit that communicates between the control valves 51a, the first control valve 51a, and the radiator 5, has a second control valve 51b, and extends in the middle to the vicinity of the lubricating oil heat transfer section 41b. 50 is provided. Normally, the second control valve 51b is closed and the first control valve 51a is open. When the compressor 2 is operated under operating conditions with a high compression ratio or in the summer when the outside air temperature is high, the lubricating oil 11 becomes hot. Therefore, a discharge temperature sensor 48 that detects the temperature of the refrigerant compressed from the compressor 2 is provided in the discharge pipe, and when the discharge temperature of the refrigerant exceeds the set value, the second control valve 51b is opened and the first control valve 51b is opened. By closing the control valve 51a of the above, the low-pressure low-temperature refrigerant decompressed by the expansion device 4 is allowed to flow through the bypass circuit 50, thereby causing the refrigerant and the lubricating oil 11 to flow between the low-pressure refrigerant section 52 and the lubricating oil heat transfer section 41b. Let the heat exchange. As a result, the lubricating oil 11 is cooled. When the discharge temperature of the refrigerant falls below the specified value, the second control valve 51b is closed, the first control valve 51a is opened, and normal operation is resumed. The heat exchange between the low temperature refrigerant section 52 and the lubricating oil heat transfer section 41b may be performed by using a known fin tube heat exchanger, or by winding the low pressure refrigerant section 52 around the lubricating oil heat transfer section 41b. You may. Further, a fan may be provided in the vicinity of the low-pressure refrigerant portion 52 to exchange heat.

Although the present embodiment has been described with a rotary compressor, the same effect can be obtained even with a scroll compressor.

Although some embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, as well as in the scope of the invention described in the claims and the equivalent scope thereof.

1 ... Refrigeration cycle device, 2 ... Compressor, 3 ... Heat absorber, 4 ... Expansion device, 5 ... Evaporator, 7 ... Sealed case, 8 ... Compression mechanism, 11 ... Lubricating oil, 41 ... Oil circuit, 42 ... Pump , 43 ... Heating means, 44 ... Oil reservoir, 45 ... Oil suction part, 52 ... Low pressure refrigerant part

Claims (5)

It is equipped with a compressor, a radiator connected to the compressor, an expansion device, and a heat absorber.
The compressor has a sealed case filled with a refrigerant and provided with an oil sump at the bottom for storing lubricating oil.
A compression mechanism unit housed in the airtight case and compressing the refrigerant, and
An oil circuit configured so that the lubricating oil can be circulated between the outside of the closed case and the inside of the closed case without operating the compression mechanism portion.
A heating means for heating the lubricating oil in the oil circuit is provided.
The oil circuit is a hollow pipe having a substantially U-shaped appearance, and has a lower connecting pipe that penetrates vertically through the sealed case and a lower connecting pipe that is located above the lower connecting pipe and penetrates vertically through the sealed case. The upper connecting pipe has a lubricating oil heat transfer portion extending substantially parallel to the closed case between the lower connecting pipe and the upper connecting pipe, and the upper connecting pipe is higher than the oil level of the oil sump. A refrigeration cycle device characterized by being located below. The refrigeration cycle apparatus according to claim 1, wherein the oil circuit includes a forced circulation means for circulating the lubricating oil. The refrigeration according to claim 1 or 2, wherein the pipe forming the oil circuit projects inward from the inner surface of the closed case and is made of a material having a higher thermal conductivity than the closed case. Cycle device. The refrigeration cycle apparatus according to claim 1 to 3, further comprising a cooling mechanism for cooling the lubricating oil in the oil circuit outside the closed case during the operation of the compression mechanism unit. The refrigeration cycle apparatus according to claim 4, wherein the cooling means uses a low-pressure refrigerant that flows in the refrigeration cycle.

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