JPH0230995A - Closed type motor-driven compressor - Google Patents

Abstract

PURPOSE:To prevent the deterioration in the characteristics of an electric motor, and to ensure the prevention of damage of the motor by providing a cooling device by which the coil part of the motor is cooled by circulating coolant through the coil part, and by which the temperature rise of a permanent magnet is regulated. CONSTITUTION:In the inside of a closed compressor case 1, a scroll type compressor 24, 26, and a d.c. motor 10 for driving this compressor are provided. A cooling device 36 is provided, by which the temperature rise of a permanent magnet 13 is regulated by circulating coolant through the coil part 17 of the motor 10 to cool the coil part 17, when the drive of the motor-driven compressor 10 is stopped. Thus, the deterioration in the characteristics of the motor can be prevented, and also the prevention of damage of the motor can be ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a hermetic electric compressor suitable for use in air conditioners, refrigeration equipment, and the like.

(Prior Art) In recent years, scroll compressors using a DC motor as a drive source have been used. This scroll type compressor compresses refrigerant by configuring a plurality of compression chambers between two scroll members that move eccentrically with respect to each other.
Compared to M, it has the advantage that restart torque is small, gas leakage during compression is small, and sliding resistance is small, so high speed rotation is possible. Furthermore, there are brushless motors using rare earth permanent magnets as direct current motors, which have the advantage of ensuring sufficient starting torque and being lightweight and compact.

In such a hermetic electric compressor, especially when a DC brushless motor is used as the motor, it is necessary to control the temperature rise of the permanent magnet part, so low-pressure suction refrigerant gas is usually guided to the motor part for cooling. A method has been adopted to
This ensures motor output and efficiency.

(Problem B to be Solved by the Invention) However, in the conventional hermetic motor compressor described above, the suction refrigerant gas is guided to cool the motor section, so that when the motor section is cooled, for example after high load operation, If the drive suddenly stops, the introduction of suction refrigerant gas will be stopped, and the coils of the motor will not be cooled by the refrigerant gas, and the temperature of the magnets will rise due to the thermal energy remaining in the coils, causing irreversible damage. There was a problem in that demagnetization occurred and the characteristics of the motor deteriorated.

Therefore, in the present invention, even when the drive of the electric motor is stopped,
The purpose of the present invention is to provide a hermetic electric compressor that can reliably cool the motor part.

(Means for Solving the Problems) The hermetic electric compressor of the present invention includes, in a sealed case,
A hermetic electric compressor that has a scroll compressor and a DC motor that drives the compressor, wherein when the electric compressor is stopped, the coil portion of the electric motor is cooled by passing refrigerant through the coil portion of the electric motor. The magnet is equipped with a cooling device that cools the permanent magnet and regulates the temperature rise of the permanent magnet.

(Function) Therefore, when the electric compressor stops driving, the cooling device flows refrigerant through the coil section of the electric motor, which cools the coil section and prevents the temperature of the permanent magnet from rising, thereby preventing irreversible demagnetization. No generation occurs, and the characteristics of the motor will not be impaired.

(Example) An embodiment of the present invention will be described below based on the drawings.

FIG. 1 is a cross-sectional view showing the electric compressor of this embodiment, in which 1 is a compressor case joined in a hermetically sealed state, 2 is a refrigerant suction pipe, 3 is a compressed refrigerant discharge pipe, and 4 is a compressor case connected in a sealed state. , 5 are upper bearing support plates joined to each other and fixed to the case 1;
6 is a lower bearing support plate fixed to the case 1, and the drive shaft 11 of the electric motor 10 is connected to the upper bearing support plate 4.5 via a bearing 7 or 8, and to the lower bearing support plate 6 via a bearing 9. Supported.

A cylindrical magnetic back yoke 12 is fixed to the drive shaft 11, and a permanent magnet 13 magnetized to the NS pole is attached to the circumferential surface of the yoke 12.
or installed. A rotor 14 is constituted by the yoke 12 and the permanent magnets 13. Further, around the permanent magnet 13, a cylindrical stator 15 made of a laminated iron core is fixed to the lower bearing support plate 6 via a support member 16. A winding coil 17 is inserted into the stator 15 to constitute a brushless DC motor 10. Furthermore, the above-mentioned yoke 1
A Hall element 18 is attached to the support member 16 so as to face the side of the permanent magnet 13 on the circumferential surface of the rotor 14, thereby detecting the position of the magnet 13 of the rotor 14 and detecting the rotation of the motor.

This Hall element 18 can stably detect the magnet position without being affected by dirt or the like even in a closed motor where lubricating oil is mixed in the gas. Further, an annular pipe 21 is disposed above the magnet 13 and coil 17 of the electric motor 10 in the case 1, and the annular pipe 21 has a plurality of nozzle holes 2 facing toward the magnet 13 and the coil 17.
2 is provided. Note that 19 indicates a lead wire that excites the winding coil 17.

Further, a disc-shaped eccentric part 11A eccentric from the drive shaft 11 by a predetermined distance is integrally fixed to one end side of the drive shaft 11, and this eccentric part 11A is attached to the movable scroll member 2.
It is inserted into the connecting portion 24A of No. 4 via a bearing 25,
The movable scroll member 24 is rotated by the rotation of the eccentric portion 11A.
is driven. The movable scroll member 24 is connected to the case 1
The movable scroll member 24 is meshed with the fixed scroll member 26 fixed to the fixed scroll member 26, and there is a space between the back side of the movable scroll member 24 and the upper bearing support plate 4, which allows only the revolution of the movable scroll member 24 without allowing the movable scroll member 24 to rotate. A ball 27 is interposed. Then, the movable scroll member 24 slides according to the eccentricity of the fixed scroll member 26 and the drive shaft 11, gradually reducing the volume of the closed chamber formed by the meshing, and refrigerant supplied from the suction pipe 2 through the electric motor 10. The compressed refrigerant is discharged from the discharge port 28 of the fixed scroll member 26 through the discharge pipe 3. Furthermore, 29
is a reed valve.

Furthermore, a refrigeration cycle of an air conditioner is interposed between the discharge pipe 3 and the suction pipe 2.

Further, the discharge pipe 3 is branched and connected to the inlet side of a liquid storage tank 31, and the outlet side of this tank 31 is connected to the annular pipe 21 via a pipe 32. An electromagnetic valve 33 is provided which closes the pipe 32 and opens the pipe 32 when the compressor is stopped. Further, a plurality of heat radiation fins 34 are provided on the outer surface of the tank 31. In addition, the annular pipe 21 and the tank 3
1. Pipe 32, electromagnetic valve 33 and radiation fin 34
The cooling device 36 is configured by the following.

In such an electric compressor, the movable scroll member 24 is rotated as the electric motor 10 is driven, and the refrigerant introduced from the suction pipe 2 causes the magnet 1 of the electric motor 10 to rotate.
3 and the coil 17, the refrigerant is compressed in the compression chamber formed by both scroll members 24 and 26, and the condensed refrigerant is sent to the air conditioning refrigeration cycle through the discharge pipe 3. In this case, the condensed refrigerant 35 is stored in the drip tank 31 connected to the discharge pipe 3. When the drive of the electric motor 10 is stopped, the Hall element 18 detects that the rotation has stopped, and accordingly, the electromagnetic valve 33 opens the pipe 32, and the liquid storage tank 31
The condensed refrigerant 35° inside passes through the pipe 32 to the annular pipe 2.
1 and is emitted from each nozzle hole 22 of the annular pipe 21 toward the magnet 13 and coil 17 of the electric motor 10.

Therefore, even when the motor is stopped, the motor 10
It is possible to prevent the temperature of the magnet section from increasing due to thermal energy remaining in the coil section of the magnet, thereby preventing an adverse effect on the magnet.

Incidentally, the liquid storage tank 31 is provided with a large number of radiation fins 34 as in the above embodiment, but as shown in FIG. 2, the suction pipe 2 is wound around the tank instead of the radiation fins 34. As a result, the tank 31 can be cooled by the refrigerant in the suction pipe 2, and the refrigerant inside the tank 31 can be maintained in a condensed state. In this case, the number of parts can be reduced and the same effects as in the previous example can be obtained.

Next, another embodiment will be explained based on FIG. 3.

FIG. 3 shows a schematic configuration of a refrigeration cycle in an air conditioner, in which a condenser 37, a receiver tank 38, and an evaporator 39 are interposed in this order between the discharge pipe 3 and the suction pipe 2 of the compressor. Further, a pipe 32 connected to the annular pipe 21 is connected to the receiver tank 38, and this pipe 32 has a solenoid valve 33 similar to the above.
is interposed.

When the compressor is stopped, the pipe 32 is opened by the electromagnetic valve 33 as in the previous example, and the coil portion is cooled by jetting refrigerant from the nozzle 22 of the annular pipe 21.

Furthermore, FIG. 4 shows another embodiment, in which a pipe 32 connected to the annular pipe 21 is communicated with the atmosphere, and a solenoid valve 33 is interposed in this pipe 32. In this case, the temperature of the stator 15 when the compressor is stopped is detected by a temperature sensor, etc., and if the temperature exceeds a specified temperature, the pipe 32 is opened to the atmosphere by the electromagnetic valve 33, and the refrigerant in the case 1 is By releasing the gas into the atmosphere, a flow of refrigerant gas is formed through the suction pipe 2, and the coil portion is cooled by this flow of refrigerant gas.

In addition, in the above embodiment, each injection hole 22 of the annular pipe 21
A solenoid valve 33 is provided with a valve that opens and closes depending on the temperature.
It is also possible to delete. For example, it may be an automatic opening/closing valve that is formed of a shape memory alloy or the like and opens the nozzle hole 22 when the reference temperature is reached.

(Effects of the Invention) As explained above, according to the present invention, at least the coil portion of the electric motor is cooled by the condensed refrigerant when the drive of the compressor is stopped. It is possible to prevent the temperature of the magnet portion from increasing and causing irreversible demagnetization and deterioration of the characteristics of the motor, and also to eliminate the negative influence on the magnet, thereby making it possible to ensure the prevention of damage to the motor.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing a cooling system for an electric compressor according to a first embodiment of the present invention, FIGS. FIG. 3 is a schematic diagram showing a cooling system related to the actual male side. 1... Case 10... Electric motor 17... Coil part 35... Refrigerant 36... Cooling device

Claims (1)

[Claims] In a hermetically sealed electric compressor that includes a scroll compressor and a DC motor that drives the compressor in a hermetically sealed case, when the electric compressor stops driving, the coil portion of the electric motor What is claimed is: 1. A hermetic electric compressor comprising a cooling device that cools the coil section by passing a refrigerant through the coil section and regulates the temperature rise of the permanent magnet.