JP2005076528A - Electric compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric compressor surely cooling an electric motor, preventing excessive temperature rise of sucked coolant, and reducing power for a compression mechanism by maintaining pressure of a compression mechanism chamber high without deteriorating smoothness of action of compression mechanism. <P>SOLUTION: Since the sucked coolant from an external coolant circuit 20 flows once in a motor chamber 122 via a motor cooling passage 31, the electric motor 121 installed in the motor chamber 122 is cooled by the sucked coolant (low temperature low pressure coolant). Since the sucked coolant which cooled the electric motor 121 detours the compression mechanism chamber 134 or is returned to a suction chamber 111 with being separated from the compression mechanism chamber 134, temperature of the sucked coolant returned to the suction chamber 111 does not become excessively high. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electric compressor used in a vehicle air conditioner or the like.

  A vehicular air conditioner is equipped with a compressor that compresses a refrigerant in order to perform indoor cooling or the like, and an electric motor is incorporated as the compressor. By driving the electric motor, a compression mechanism (piston or the like) built in the compressor is driven, and high-pressure refrigerant is discharged.

  By the way, when the vehicle interior is cooled during a high load such as in midsummer, the electric motor must be operated at a high speed for a long time so as to cope with the high load. However, when the high-speed rotation operation is continued, the amount of heat generated from the electric motor increases, and accordingly, the atmospheric temperature of the electric motor becomes very high, and as a result, the rotation efficiency of the electric motor decreases. Had.

In order to solve such problems, an electric compressor described in Japanese Patent Application Laid-Open No. 2001-193639 has been proposed. This electric compressor has a structure in which a part of the refrigerant that passes through the evaporator and returns to the suction chamber, that is, a so-called suction refrigerant flows in the motor chamber and the compression mechanism chamber, and cools the electric motor in the motor chamber and the compression mechanism in the compression mechanism chamber. It has become.
JP 2001-193639 A

  However, in the latter electric compressor, since the sucked refrigerant is returned to the motor chamber and the compression mechanism chamber, both the heat generated by the electric motor and the heat generated by the compression mechanism are absorbed by the sucked refrigerant, and the sucked refrigerant becomes excessive. The problem is that the temperature rises and the refrigeration effect decreases significantly. Further, since the suction refrigerant that has flowed into the compression mechanism chamber also takes in lubricating oil in the compression mechanism chamber, it has a problem of hindering the smooth operation of the compression mechanism.

  In view of the above-mentioned conventional problems, the object of the present invention is to reliably cool the electric motor, to prevent an excessive increase in the temperature of the sucked refrigerant, and without impairing the smoothness of the operation of the compression mechanism. Another object of the present invention is to provide an electric compressor capable of reducing the power of the compression mechanism while maintaining the pressure in the compression mechanism chamber high.

  In order to solve the above-described problems, the present invention provides a rear housing having at least a discharge chamber for introducing a discharge refrigerant to an external refrigerant circuit and a suction chamber into which the intake refrigerant from the external refrigerant circuit is introduced, and electric An external refrigerant circuit in an electric compressor comprising: a motor housing having a motor chamber in which a motor is installed; and a compression mechanism housing having a compression mechanism chamber disposed between the rear housing and the motor housing and having a compression mechanism installed therein A cooling passage through which the refrigerant drawn from the motor is led to the motor chamber, and the refrigerant drawn into the motor chamber bypasses the compression mechanism chamber or is separated from the compression mechanism chamber to the suction chamber, the compression mechanism housing, and the motor housing When the internal pressure of the compression mechanism housing exceeds the seal pressure, the gas in the compression mechanism housing is removed from the motor housing. And it has a structure having a sealing member to derive the managing.

  According to the first aspect of the present invention, since the suction refrigerant from the external refrigerant circuit once flows into the motor chamber through the motor cooling passage, the electric motor installed in the motor chamber is cooled by the suction refrigerant (low temperature low pressure refrigerant). Further, since the suction refrigerant that has cooled the electric motor bypasses the compression mechanism chamber or is separated from the compression mechanism chamber and returned to the suction chamber, the suction refrigerant returned to the suction chamber does not reach an excessively high temperature.

  Furthermore, since the compression mechanism housing and the motor housing are partitioned by the partition wall, lubricating oil in the compression mechanism chamber does not leak into the motor chamber inadvertently.

  Furthermore, by driving the compression mechanism, blow-by gas flows from the suction chamber into the compression mechanism chamber, and the internal pressure of the compression mechanism chamber increases. When the internal pressure in the compression mechanism chamber exceeds the seal pressure, the gas in the compression mechanism chamber is led out to the motor chamber, whereby the internal pressure in the compression mechanism chamber is maintained at a predetermined high pressure value. Accordingly, for example, when the piston of the compression mechanism is driven, the back pressure of the piston is maintained so as to increase, so that the power required for compressing the refrigerant can be reduced.

  The seal member may be interposed between the partition wall and the shaft that penetrates the partition wall.

  According to a third aspect of the present invention, in the electric compressor according to the first aspect, one of the return passages connecting the motor chamber and the suction chamber in the motor cooling passage is provided in a lower portion of the peripheral wall of the compression mechanism housing. It has a structure.

  According to the invention of claim 3, since one of the return passages is formed in a lower part of the peripheral wall of the compression mechanism housing, the oil staying in the motor chamber returns smoothly from the motor chamber toward the suction chamber.

  According to a fourth aspect of the present invention, in the electric compressor according to any one of the first to third aspects, the bearing for restricting the movement of the shaft in the axial direction is an inner wall of the compression mechanism housing on the one end side of the shaft or the other end side of the shaft. Thus, the motor housing is installed on at least one of the inner walls.

  According to the invention of claim 4, the bearing for restricting the movement of the shaft in the axial direction is installed on the inner wall of the housing. Thereby, since it is not necessary to provide a bearing in a partition, a thrust load is not added with respect to a partition, and a partition can be formed thinly.

  According to the first aspect of the present invention, the electric motor is surely cooled by the suction refrigerant, and the temperature of the suction refrigerant that is subsequently returned to the suction chamber does not become excessively high. In addition, the lubricating oil in the compression mechanism chamber does not accidentally leak into the motor chamber. Furthermore, the power required for compressing the refrigerant can be reduced.

  According to invention of Claim 2, the clearance gap between a shaft and a partition can be sealed with a sealing member.

  According to the invention of claim 3, the suction refrigerant that is liquid can be smoothly returned from the motor chamber toward the suction chamber.

  According to the invention of claim 4, since it is not necessary to provide the bearing on the partition wall, the partition wall can be formed thin, and the electric compressor can be miniaturized.

  1 and 2 show an embodiment of an electric compressor according to the present invention. FIG. 1 is a sectional view of the electric compressor, and FIG. 2 is a plan view showing a partition wall. In the present embodiment, a single-head piston type swash plate type electric compressor (hereinafter referred to as a compressor) will be described as an example of the electric compressor.

  First, the overall structure of the compressor 10 will be described with reference to FIG. The compressor 10 includes a rear housing 11, a motor housing 12, a compression mechanism housing 13 disposed between the rear housing 11 and the motor housing 12, and a valve plate device 14.

  A suction chamber 111 and a discharge chamber 112 are formed in the rear housing 11. The suction chamber 111 communicates with a return passage 316 of the motor cooling passage 31 described later, and the discharge chamber 112 communicates with the external refrigerant circuit 20.

  The motor housing 12 has a motor chamber 122 in which an electric motor 121 is disposed. The electric motor 121 has a stator 121a and a rotor 121c fixed to the shaft 121b. The shaft 121 b extends over the motor housing 12 and the compression mechanism housing 13, and a shaft is formed by a thrust bearing 121 d installed on the inner wall 12 a of the motor housing 12 and a thrust bearing 133 a installed on the inner wall 13 a of the compression mechanism housing 13. It is supported. The thrust bearings 121d and 133a receive the thrust load of the shaft 121b.

  The compression mechanism housing 13 includes a cylinder block 131 on the rear housing 11 side and a front housing 132 on the motor housing 12 side, and has a compression mechanism chamber 134 in which the compression mechanism 133 is installed. A plurality of cylindrical cylinder bores 133b are formed in the cylinder block 131, and a single-headed piston 133c is accommodated in the cylinder bore 133b so as to be able to reciprocate linearly. The compression mechanism chamber 134 has a swash plate 133d fixed to the shaft 121b. A single-head piston 133c is connected to the periphery of the swash plate 133d via a slidable shoe 133e, and the single-head piston 133c reciprocates in each cylinder bore 133b by the rotation of the swash plate 133d. The compression mechanism 133 is configured by the members 133a, 133b, 133c, 133d, and 133e described above.

  The valve plate device 14 is installed between the rear housing 11 and the cylinder block 131. This valve plate device 14 is well known, and when one single-headed piston 133c moves away from the valve plate device 14, the suction refrigerant in the suction chamber 111 is sucked into the cylinder bore 133b through the suction hole 141a of the valve plate device 14. Is done. Further, when the other single-headed piston 133 c moves in a direction approaching the valve plate device 14, the suction refrigerant in the cylinder bore 133 b is compressed and is pumped to the discharge chamber 112 through the discharge hole 141 b of the valve plate device 14. Then, the high-pressure refrigerant pumped to the discharge chamber 112 is discharged toward the external refrigerant circuit 20.

  The external refrigerant circuit 20 is configured by sequentially connecting refrigerant circulation devices such as a condenser, an expansion valve, and an evaporator. The condenser is connected to the discharge chamber 112 and the evaporator is connected to the suction chamber 111. Are connected.

  The configuration of the electric compressor as described above is well known, and the characteristic part of the present invention is the following structure.

  The compressor 10 according to the present embodiment includes a partition wall 15 that partitions the housings 12 and 13 between the compression mechanism housing 13 and the motor housing 12. The partition wall 15 is formed in a disk shape as shown in FIG. In the center of the partition wall 15, there is a seal storage box 151 that bulges left and right and is integrally formed. The seal storage box 151 is filled with an annular seal member 16. For example, soft resin or rubber is used as the material of the seal member 16. The left and right side plates of the seal storage box 151 are formed with first through holes 151a having a diameter slightly larger than the outer diameter of the shaft 121b. On the other hand, a second through hole 161a through which the shaft 121b passes is formed in the center of the seal member 16. The outer peripheral surface of the shaft 121b is always in contact with the inner peripheral surface of the second through hole 161a.

  Further, the compressor 10 according to the present embodiment has a structure in which the motor cooling passage 31 is provided in the suction refrigerant passage 30 formed between the external refrigerant circuit 20 and the suction chamber 111. The motor cooling passage 31 includes a first passage 311, a second passage 312, a third passage 313, a fourth passage 314, and a fifth passage 315. The first passage 311 is a passage formed so as to penetrate inside and outside through the side wall 12b of the motor housing 12, and communicates the external refrigerant circuit 20 and the motor chamber 122 with each other. It is introduced into the chamber 122. The second passage 312 is formed near the partition wall 16 on the side wall 12 b of the motor housing 12, and has one end communicating with the motor chamber 122 and the other end facing the side surface of the partition wall 16. The third passage 313 is formed so as to penetrate the partition wall 16, and one end thereof communicates with the second passage 312. The fourth passage 314 is formed to penetrate left and right inside the side wall 13 b of the compression mechanism housing 13, and one end thereof communicates with the second passage 312. The fifth passage 315 is formed in the rear housing 11 in an L shape. One end communicates with the fourth passage 313 and the other end communicates with the suction chamber 111. 1 shows only one system of the second to fifth passages 312 to 315, that is, the return passage 316 for returning the refrigerant from the motor chamber 122 to the suction chamber 111. As shown in FIG. It is formed over. Further, at least one of the five systems is formed so as to be positioned below the compressor 10 as shown in FIG. The second passage 312 of the motor cooling passage 31 is not required when the motor chamber 122 and the third passage 313 are formed to face each other.

  According to this embodiment, the intake refrigerant of the external refrigerant circuit 20 is circulated to the motor refrigerant passage 31 through the intake refrigerant passage 30. That is, the first passage 311, the motor chamber 122, the second passage 312, the third passage 313, the fourth passage 314, the fifth passage 315, and the suction chamber 111 circulate. Thereby, the electric motor 121 installed in the motor chamber 122 is cooled by the suction refrigerant.

  Further, the suction refrigerant that has passed through the motor chamber 122 flows into the suction chamber 111 through the third passage 313 formed in the side wall 13b of the compression mechanism housing 13, and is separated from the compression mechanism chamber 134. The heat generated in 133 (for example, the sliding heat generated in the shoe 133e) is not so much absorbed by the suction refrigerant. Therefore, the suction refrigerant returned to the suction chamber 111 does not reach an excessively high temperature.

  Further, since the compression mechanism chamber 134 and the motor chamber 122 are separated by the partition wall 15 and the seal member 16, oil in the compression mechanism chamber 134 does not always flow into the motor chamber 122, and the lubrication of the compression mechanism 133 is poor. Will not cause.

  Furthermore, by driving the compression mechanism 133, blow-by gas flows from the suction chamber 111 into the compression mechanism chamber 134, and the internal pressure of the compression mechanism chamber 134 increases. When the internal pressure of the compression mechanism chamber 134 exceeds the seal pressure of the seal member 16, the gas in the compression mechanism chamber 134 is led to the motor chamber 122. As described above, since the internal pressure of the compression mechanism chamber 134 is maintained at a predetermined high value, when the piston 133c of the compression mechanism 133 is driven, the back pressure of the piston 133c is maintained to be large, and the refrigerant is compressed. The required power can be reduced.

  Furthermore, since at least one of the return passages 316 for returning the refrigerant from the motor chamber 122 to the suction chamber 111 is located below the compressor 10 (compression mechanism housing 13), the oil staying in the motor chamber 122 is sucked. The chamber 111 can be returned smoothly.

  Furthermore, since both ends of the shaft 121b are supported by thrust bearings 121d and 133a, the thrust load of the shaft 121b is received by the housings 12 and 13, respectively. Therefore, the thrust load of the shaft 121b is not applied to the partition wall 15, and the partition wall 15 can be formed thin.

  In the above embodiment, the return passage 316 is formed in the side wall 13b of the compression mechanism housing 13, but the present invention is not limited to this. For example, piping from the motor chamber 122 to the outside of the compression mechanism housing 13 may be made, and the compression mechanism housing 13 may be bypassed and connected to the suction chamber 111 by piping.

Cross section of electric compressor Plan view of bulkhead

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Electric compressor, 11 ... Rear housing, 12 ... Motor housing, 13 ... Compression mechanism housing, 12a ... Inner wall of motor housing, 13a ... Inner wall of compression mechanism housing, 14 ... Valve plate apparatus, 15 ... Septum, 16 ... Seal 20: external refrigerant circuit, 30: suction refrigerant passage, 31 ... motor refrigerant passage, 111 ... suction chamber, 112 ... discharge chamber, 121 ... electric motor, 121b ... shaft, 122 ... motor chamber, 133 ... compression mechanism, 133c ... piston, 134 ... compression mechanism chamber, 316 ... return passage.

Claims (4)

A rear housing having at least a discharge chamber for guiding the discharged refrigerant to the external refrigerant circuit and a suction chamber into which the suction refrigerant from the external refrigerant circuit is introduced; a motor housing having a motor chamber in which an electric motor is installed; and the rear housing And an electric compressor including a compression mechanism housing having a compression mechanism chamber disposed between the motor housing and the compression mechanism.
A motor cooling passage through which the suction refrigerant from the external refrigerant circuit is guided to the motor chamber, and the suction refrigerant introduced into the motor chamber is guided to the suction chamber bypassing the compression mechanism chamber or separated from the compression mechanism chamber When,
A partition partitioning the compression mechanism housing and the motor housing;
An electric compressor, comprising: a seal member interposed in the partition wall and for guiding gas in the compression mechanism housing to the motor housing when an internal pressure of the compression mechanism housing exceeds a seal pressure. The electric compressor according to claim 1, wherein the seal member is interposed between the partition wall and a shaft penetrating the partition wall. The one of the return paths which connect the said motor chamber and the said suction chamber among the said motor cooling paths has in the low-order site | part of the surrounding wall of the said compression mechanism housing. Electric compressor. The bearing for restricting the movement of the shaft in the axial direction is installed on at least one of the inner wall of the compression mechanism housing on one end side of the shaft or the inner wall of the motor housing on the other end side of the shaft. The electric compressor according to any one of claims 1 to 3.

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