JP3782478B2 - Compressor preheating device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a preheating device for a compressor mounted on an air conditioner or the like.
[0002]
[Prior art]
In a compressor mounted on an air conditioner, the refrigerant is liquefied at a low outside air temperature such as in winter, and is stored in the compressor case as a large amount of liquid mixed with low-temperature lubricating oil. If the compressor is operated in this state, a foaming phenomenon occurs due to the rapid release of the refrigerant in oil, and at the same time, the lubricating oil is also taken away, so that the amount of oil in the compressor is reduced and the lubrication is hindered. Become. Furthermore, when the foaming phenomenon is severe, liquid compression occurs, and this liquid compression is a main cause of compressor accidents.
[0003]
As a conventional example for preventing such a problem, for example, an apparatus described in Japanese Patent Application Laid-Open No. 62-258964 can be cited. In this device, a drive signal that lacks one phase is given to the drive motor of the compressor driven by the three-phase voltage, thereby heating the compressor without rotating the drive motor, the liquid refrigerant mixed with lubricating oil by ized gas separated from the lubricating oil, so that provided the start of operation.
[0004]
[Problems to be solved by the invention]
In the above conventional example, the compressor body is heated to raise the oil temperature, whereby the liquid refrigerant is vaporized and separated from the lubricating oil. However, the heat capacity of the compressor mounted on the air conditioner is generally large, so that a large amount of heat is consumed to raise the oil temperature until the liquid refrigerant is vaporized. For this reason, in the above conventional example, the operation start-up time of the compressor becomes long, and there is a drawback that energy used other than the original air conditioning operation becomes large.
By the way, in recent years, from the viewpoint of downsizing the outdoor unit of an air conditioner, a so-called lateral compression has a drive motor in which a rotating shaft is installed horizontally and a coil is arranged on a circumference surrounding the rotating shaft. The machine is attracting attention. The present invention has been made to solve the above-mentioned conventional drawbacks in such a horizontal compressor, and its object is to reduce the operation start-up time of the compressor by improving the thermal efficiency during preheating. It is an object of the present invention to provide a preheating device for a compressor that can be shortened and save energy.
[0005]
[Means for Solving the Problems]
Accordingly, the preheating device motor shaft 44 of the compressor according to claim 1 is installed horizontally, the drive motor 16 having a coil arranged so as to surround the motor shaft 44 is provided , and the drive motor 16 is energized so as not to rotate. In the preheating device for the compressor that heats the refrigerating machine oil 50 by generating heat in the coils, the drive motor 16 is a three-phase induction motor, and the two-phase coils 45, 46 of the three-phase coils 42, 45, 46 are provided. When a current is passed between the two-phase coils 45 and 46 and the remaining one-phase coil 42 in the same phase connection, the remaining one-phase coil 42 is stored in the bottom of the compressor case 47. It arrange | positions so that the machine oil 50 may be contacted .
[0008]
[Action]
In the compressor preheating apparatus according to the first aspect, the heating coil 42 is in contact with the refrigerating machine oil 50 accumulated at the bottom of the compressor case 47. Therefore, the refrigerating machine oil 50 can be directly heated, and the refrigerant can be efficiently vaporized.
[0009]
Moreover, in the preheating device for the compressor according to the first aspect, the coil 42 having the largest heat generation amount among the three heating coils 42, 45, 46 directly heats the refrigerating machine oil 50. Further, the preheating efficiency can be improved.
[0011]
【Example】
Specific examples of the preheating device for a compressor according to the present invention will be described in detail with reference to the drawings.
[0012]
FIG. 1 shows an embodiment in which the present invention is applied to an air conditioner. In the figure, 1 is a compressor, 2 is a four-way switching valve, 3 is an outdoor heat exchanger, 4 is an expansion valve, and 5 is an indoor heat exchanger. These devices 1 to 5 are connected so that the refrigerant can circulate through the refrigerant pipes 6. During the cooling operation, the four-way switching valve 2 is switched as indicated by the solid line in the figure to circulate the refrigerant as indicated by the solid line arrow. Thus, the indoor heat exchanger 5 repeatedly cools the room by repeatedly radiating the amount of heat absorbed from the room to the outside air by the outdoor heat exchanger 3. On the other hand, at the time of heating operation, the four-way switching valve 2 is switched as indicated by the broken line in the drawing to circulate the refrigerant as indicated by the broken line arrow. Thus, the room is heated by reversing the amount of heat exchanged during the cooling operation.
[0013]
A three-phase commercial power source 10 is connected to the cooling / heating device incorporating the compressor 1. An inverter 12 that controls the capacity of the compressor 1 is provided in the power supply circuit of the air conditioner. The inverter 12 changes the supply voltage value to the compressor 1 and its operating frequency. Thus, while changing the drive torque of the compressor 1, the capacity thereof is smoothly increased or decreased according to the air conditioning load, and the air conditioning capacity is made to correspond to the air conditioning load.
[0014]
FIG. 2 shows the internal configuration of the inverter 12. In the converter unit 15, the alternating voltage from the three-phase power supply 10 is converted into direct current, and in the inverter unit 17, the direct current converted by the converter unit 15 is converted into a voltage value different from the power supply voltage and the power supply frequency of the commercial power supply 10. And converted into a three-phase alternating current having a frequency value and applied to the drive motor (three-phase induction motor) 16 of the compressor 1. The inverter unit 17 performs on-off control of the six power transistors Tu, Tv, Tw, Tx, TY, and Tz that are driven by applying a voltage to the compressor drive motor 16 and the six power transistors. And a control circuit 18 for outputting a VW coil in-phase connection signal to the drive motor 16. Further, a room temperature signal of a room temperature sensor TH for detecting a room temperature provided in the indoor heat exchanger 5 and a status signal of the operation / stop switch 13 are input to the control circuit 18. Note that reference numeral 19 in FIG. 2 denotes a feedback diode.
[0015]
FIG. 3 shows the internal configuration of the control circuit 18. Reference numeral 20 denotes a microcomputer incorporating a CPU and the like. The microcomputer 20 has a function of outputting a cooling operation command signal or a heating operation command signal according to the season. Further, the difference between the room temperature signal from the room temperature sensor TH and the room temperature target value (set value), that is, the air conditioning load is calculated, and the inverter unit 17 receives each command signal of voltage value and frequency value corresponding to the air conditioning load. It has a function to generate. Furthermore, it has a function as a stop time detecting means for detecting when the operation is stopped, and outputs a VW coil in-phase connection signal to the drive motor 16 when the stop time of the heating operation is detected.
[0016]
Reference numeral 21 denotes a three-phase control signal generator incorporating a ROM, an oscillator, a counter, and the like. The three-phase control signal generator 21 generates a continuous three-phase waveform as the three-phase control signal having a voltage value and a frequency according to the air conditioning load in accordance with the voltage command signal and the frequency command signal from the microcomputer 20. Are output to the six power transistors Tu to Tw and Tx to Tz.
[0017]
FIG. 4 is a schematic cross-sectional view showing the configuration of the compressor 1. In the figure, 16 is a compressor drive motor and 44 is a motor shaft, which are arranged substantially horizontally. The rotor 43 rotates on a vertical plane orthogonal to the motor shaft 44, and supplies power to the compression mechanism 41 including a piston, a cylinder, and the like via the motor shaft 44. The low-pressure gas refrigerant is sucked into the compression mechanism 41 through the suction port 40, compressed, and then discharged as a high-pressure gas refrigerant from the discharge port 39 to circulate through the refrigerant pipe 6. 42 is a U-phase coil. The U-phase coil 42 is connected to the power transistors Tu and Tx, and the U-phase is supplied from the three-phase waveform by the inverter 12.
[0018]
FIG. 5 shows a cross-sectional view of the compressor drive motor 16 taken along a vertical plane orthogonal to the motor shaft 44. In the figure, 45 and 45 are W-phase coils, which are connected to power transistors Tw and Tz of the inverter unit 17. Reference numerals 46 and 46 denote V-phase coils, which are connected to the power transistors Tv and TY of the inverter unit 17. 50 shows the state of the refrigeration oil when the operation is stopped. The main component of the refrigerating machine oil 50 is lubricating oil, but a large amount of liquefied refrigerant is mixed at a low outside air temperature.
[0019]
When the operation of the compressor 1 is stopped, the refrigerating machine oil 50 is collected at the bottom of the compression soot case 47, and the U-phase coil 42 is disposed therein.
[0020]
In the embodiment of the above configuration, during the air conditioning operation, the control circuit 18 controls the six power transistors Tu, Tv, Tw, Tx, TY, and Tz with three-phase control of the voltage value and the frequency according to the air conditioning load. A signal is output. As a result, a driving torque corresponding to the supply voltage value of the three-phase waveform applied is generated in the compressor operating motor 16, and the compressor driving motor 16 rotates at a rotation speed corresponding to the supply frequency. As a result, the capacity of the compressor 1 is increased or decreased to better cope with the air conditioning load.
[0021]
On the other hand, when the heating operation is stopped at a low outside temperature such as in winter, the control circuit 18 connects the V-phase coil and the W-phase coil in phase. As a result, a single-phase alternating current is applied to the U-phase, V, and W-phase coils, and the coils generate heat without rotating the compressor drive motor 16.
[0022]
FIG. 6 shows the situation at this time. In the figure, 16 is a compressor drive motor, 42 is a U-phase coil, 46 is a V-phase coil, and 45 is a W-phase coil. Further, one end of the W-phase coil 45 is connected in phase with one end of the V-phase coil 46 according to a command from the control circuit 18. Therefore, if the current value flowing through U-phase coil 42 is I, the current values flowing through V-phase coil 46 and W-phase coil 45 are both halved. That is, at the time of the heating, the U-phase coil 42 among the three coils has the maximum heat generation amount. As shown in FIG. 5, since the U-phase coil 42 is installed inside the refrigerating machine oil 50, the oil 50 can be directly heated by the coil having the maximum calorific value, thereby efficiently supplying the refrigerant. It can be vaporized and separated from the lubricating oil.
[0024]
Although specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention. For example, in the first embodiment, the U-phase coil 42 is brought into contact with the refrigerating machine oil 50, and the V-phase coil 46 and the W-phase coil 45 are connected in phase, but the V-phase coil 46 is brought into contact with the refrigerating machine oil 50. 42 and the W-phase coil 45 may be connected in phase, or the W-phase coil 45 may be in contact with the refrigerating machine oil 50 and the U-phase coil 42 and the V-phase coil 46 may be connected in phase.
[0025]
【The invention's effect】
As described above, in the compressor preheating device of claim 1, since the heating coil is in contact with the refrigerating machine oil accumulated at the bottom of the compressor case, the refrigerating machine oil can be directly heated and generated. Heat can be efficiently transferred to refrigeration oil. Therefore, the oil temperature can be raised within a short time with a small amount of heat, and a quick heating effect can be obtained at the start of heating operation in winter or the like. Moreover, since the amount of heat required to keep the oil temperature constant may be small, energy saving can be achieved.
[0026]
Moreover, in the preheating device for a compressor according to claim 1, the one having the largest heat generation amount among the three heat generating coils directly heats the refrigerating machine oil, so that the preheating efficiency is further improved. Is possible. Therefore, the quick heating effect and energy saving are further improved.
[Brief description of the drawings]
FIG. 1 is a refrigerant piping system diagram of an air conditioner in an embodiment of the present invention.
FIG. 2 is an electric circuit diagram showing an internal configuration of an inverter of the device.
FIG. 3 is a block diagram showing an internal configuration of a control circuit of the device.
FIG. 4 is a schematic cross-sectional view showing a configuration of a compressor of the apparatus.
FIG. 5 is a schematic cross-sectional view showing the relationship between the compressor motor coil and the refrigerating machine oil of the apparatus.
FIG. 6 is a principle diagram illustrating a preheating operation in the first embodiment.
[Explanation of symbols]
1 Compressor 16 Compressor drive motor 42 U-phase coil 44 Motor shaft 47 Compressor case 50 Refrigeration machine oil

Claims (1)

A motor shaft (44) is installed horizontally, and a drive motor (16) having a coil disposed so as to surround the motor shaft (44) is provided . The coil is heated by energizing the drive motor (16) so as not to rotate. In the preheating device for the compressor that heats the refrigeration oil (50) , the drive motor (16) is a three-phase induction motor, and the two-phase coils (42), (45), and (46) have two phases. When the coils (45) and (46) are connected in phase, and current flows between the coils (45) and (46) of both phases and the remaining one-phase coil (42), the remaining one-phase coil A preheating device for a compressor, wherein the coil (42) is disposed so as to come into contact with the refrigerating machine oil (50) accumulated at the bottom of the compressor case (47) .

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