JPH11303737A - Motor-driven compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a motor-driven compressor compact by forming a cam hole at the center section of a rotor stored in the sealed container of an electric motor, inserting a fixed shaft at the center section of the cam hole, and assembling a compression mechanism constituted of a cylinder and a piston with the fixed shaft. SOLUTION: When an electric motor 10 is excited through a terminal 14 to rotate a rotor 12, a piston 32 kept in slide contact with the cam face 21 a of an eccentric cam hole 21 is reciprocated in a cylinder 31. When the piston 32 approaches the bottom dead center, the pressure in the cylinder 31 is lowered. When the pressure becomes a prescribed pressure, an intake valve 36 is opened, and coolant gas is sucked from an intake passage 35. When the piston 32 approaches the top dead center, the coolant gas in the cylinder 31 is compressed to a high pressure. When the pressure becomes a prescribed pressure, a discharge valve 38 is opened, and the high-pressure coolant gas is discharged from a discharge passage 37. All members constituting a compression mechanism constituted of the cylinder 31, piston 32, intake valve 36 and discharge valve 38 are stored in the rotor 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric compressor used for a home or vehicle air conditioner.

[0002]

2. Description of the Related Art Conventionally, in this type of electric compressor,
The mechanical part of the compressor and the electric motor were connected in series by a shaft. For this reason, there is a problem that the electric compressor becomes longer in the motor axis direction. In particular, when the compressor is a hermetic type, the electric motor and the mechanical part of the compressor are housed in a hermetic container, which causes a problem that the hermetic container becomes large and the installation space and weight increase. To solve such a problem, Japanese Patent Laid-Open Publication No.
There is an invention described in Japanese Patent Publication No. According to the present invention, the stator of the motor is fixed to the inner surface of the casing, the rotor of the motor is rotatably supported by the casing via the main shaft, and the piston is reciprocated at a predetermined interval with respect to the end surface of the rotor. A swash plate is provided as a motion transmission mechanism for this. In addition, a plurality of cylinders and pistons that are inclined in the centrifugal direction toward the swash plate with respect to the main shaft are arranged on a fixed circumference in the rotor of the motor. However, in the case of the present invention, since a plurality of pistons are arranged on a fixed circumference in the rotor, the diameter of the rotor increases, and a swash plate as a motion transmission mechanism is arranged outside the rotor. As a result, the lengthwise direction is also longer, leaving room for improvement.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the problems existing in the prior art. It is an object of the present invention to provide a compact electric compressor by incorporating the entire compression mechanism in a rotor of an electric motor.

[0004]

According to a first aspect of the present invention, there is provided an electric motor having a sealed container, a stator, a rotor, and the like built in the sealed container.
A cam hole having a cam surface arranged in the center axis direction at the center of the rotor, a fixed shaft arranged in the center axis direction at the center of the cam hole, and fixed to the closed container; A cylinder drilled in the radial direction of the fixed shaft and having one end opened to the outer peripheral surface of the fixed shaft, slidably and reciprocally housed in the cylinder, and further, the outer end surface is in sliding contact with the cam surface, A piston formed to reciprocate by the cam surface with rotation of the rotor, and a suction passage formed at one end of the fixed shaft so as to communicate with the cylinder via a suction valve; So that it communicates with the cylinder via the discharge valve
A discharge passage formed at the other end of the fixed shaft.

According to a second aspect of the present invention, the plurality of cylinders and pistons are provided on the fixed shaft in the axial direction of the fixed shaft.

[0006] In the invention according to claim 3, the fixed shaft is
A cross-sectional shape is circular, and the cam hole has a circular cross-sectional shape and is eccentric with respect to a center axis of the rotor.

In the invention according to claim 4, the fixed shaft is
The cross-sectional shape is circular, and the cam hole is formed so that the cross-sectional shape forms a plurality of cam surfaces, and the piston reciprocates the piston a plurality of times by the plurality of cam surfaces each time the rotor makes one rotation. It is characterized in that

According to a fifth aspect of the present invention, the refrigerant used in the electric compressor is carbon dioxide.

Therefore, claim 1 configured as described above.
In the electric compressor according to any one of the first to fifth aspects, the piston reciprocates by rotating the rotor of the electric motor, and the refrigerant is sucked from the external refrigerant circuit through the suction passage and the suction valve, and is compressed in the cylinder. The compressed refrigerant is discharged from a discharge passage to an external refrigerant circuit via a discharge valve. As described above, since the compression mechanism is completely integrally formed in the electric motor, the space is saved and the weight is reduced. In the field of compressors for vehicle air conditioners, the number of rotations of an electric compressor is about 3 to more than that of an engine driven compressor.
Since the cylinder volume is increased by about 10 times, the cylinder volume may be small, and it is easy to adopt such a configuration.

Further, in the electric compressor according to the present invention, since the plurality of cylinders and pistons are arranged in the axial direction of the fixed shaft, the cylinders and pistons can be arranged without increasing the external dimensions of the electric compressor. , The compression capacity is increased.

Further, in the electric compressor according to the third aspect, the cam hole and the fixed shaft have a circular cross-sectional shape, so that the manufacture is easy.

Further, in the electric compressor according to the fourth aspect, the piston is reciprocated a plurality of times each time the rotor is rotated once by the plurality of cam surfaces, so that the compression capacity is multiplied by a plurality.

Further, in the electric compressor according to the fifth aspect, since carbon dioxide is used as the refrigerant, the volume of the refrigerant is extremely small as compared with the case where a CFC-based refrigerant is used. This is about one fifth of the case where R134a is used as the system refrigerant. Therefore, in this electric compressor, the cylinder volume becomes smaller, and it becomes easier to adopt the above-described configuration for the rotor of the electric motor.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is embodied in a vehicle air conditioner will be described in detail with reference to FIGS. FIG. 1 is a longitudinal sectional view of the electric compressor according to the first embodiment, and FIG.
It is II-II sectional drawing. In these figures, reference numeral 1 denotes a closed container. The closed container 1 comprises a cup-shaped container body 2 having a circular cross section and a lid 3 for closing the open end of the container body 2. Reference numeral 10 denotes an electric motor. The electric motor 10 includes a stator 11, a rotor 12, terminals 14 for connecting a power supply, and the like. The stator 11 is fixed to the inner peripheral surface of the container body 2.

At both ends, the rotor 12 rotates via a radial bearing 13 with respect to a fixed shaft 22 having a circular cross section and protruding from the center of the lid 3 toward the side wall 2 a of the container body 2. It is freely supported. Further, thrust bearings 15 are provided between the annular projection 2b protruding from the side wall 2a of the container body 2 and the side surface of the rotor 12, and between the side surface of the lid 3 and the side surface of the rotor 12, respectively. Arranged, rotor 1
2 is configured to support a thrust load acting on the load 2. The center line of the rotor 12 and the center line of the fixed shaft 22 are supported so as to match.

At the center of the rotor 12, the rotor 1
A cam hole 21 is formed which is eccentric to a predetermined dimension with respect to the center line 2 and has a circular cross section with a predetermined diameter. A suction port 23 is formed at the center of the side wall 2a of the container body 2, and the suction port 23 is formed inside the suction port 23, that is, in the annular projection 2b.
A suction chamber 24 is formed between a and the front end surface of the fixed shaft 22. A discharge chamber 25 formed as a cylindrical space is formed on the outer surface of the central portion of the lid 3.
5 is a seat plate 27 having a discharge port 26 in the center.
Is closed.

A cylinder 31 is bored in the center of the fixed shaft 22 in the radial direction, and a cylindrical piston 32 is fitted into the cylinder 31 so as to slide and reciprocate. The piston 32 is urged by an elastic member 33 provided at the distal end of the cylinder 31, such as a coil spring, so that the base end thereof presses the cam surface 21 a of the cam hole 21. In addition, a suction passage 35 communicating with the suction chamber 24 is formed on the distal end side of the fixed shaft 22,
Further, a discharge passage 37 communicating with the discharge chamber 25 is formed on the base end side of the fixed shaft 22. The distal end of the cylinder communicates with a suction passage 35 via a suction valve 36, and further communicates with a discharge passage 37 via a discharge valve 38. The circular cam surface 21a of the cam hole 21 is
When the rotor 12 makes one rotation, the piston 32 smoothly moves to 1
The surface is processed so as to reciprocate.

Next, the operation of the electric compressor configured as described above will be described. When electricity is supplied from the terminal 14 to the electric motor 10, the rotor 12 rotates. With this rotation, the piston 32 that slides on the cam surface 21 a of the cam hole 21 that is eccentric is reciprocated in the cylinder 31. Piston 3
When 2 approaches the bottom dead center, the pressure in the cylinder 31 becomes low. When the pressure reaches a predetermined pressure, the suction valve 36 is opened, and the refrigerant gas is sucked through the suction passage 35. When the piston 32 approaches the top dead center, the refrigerant gas in the cylinder 31 is compressed to a high pressure. When the pressure reaches a predetermined pressure, the discharge valve 38 is opened, and the high-pressure refrigerant gas is discharged through the discharge passage 37. Is done. The high-pressure refrigerant gas flows from the discharge passage 37 to the discharge chamber 2.
5 and is discharged to the external refrigerant circuit through the discharge port 26. In this case, if the refrigerant used is carbon dioxide, the pressure is high because the evaporation pressure is high. For this reason, the density is high, and thus, even if the capacity is extremely small, it functions sufficiently. As described above, in the electric compressor, the piston makes one reciprocation each time the rotor 12 makes one rotation, and one cycle of suction, compression, and discharge is completed.

In the above embodiment, the cam hole 2
1. Since the members constituting the compression mechanism such as the fixed shaft 22, the cylinder 31, the piston 32, the suction valve 36, and the discharge valve 38 are all housed in the rotor 12 of the electric motor 10,
The electric compressor is configured to be compact without being elongated in the axial direction of the electric motor 10.

Next, another embodiment in which the compression mechanism is modified will be described with reference to FIGS. In these embodiments, it is assumed that the other points are the same as those in the first embodiment. Accordingly, only the compression mechanism portion is illustrated, and the same components are denoted by the same reference numerals, and the description thereof will be simplified below. Second
In the embodiment, as shown in FIG. 3, the piston 132 in FIG. 1 is elongated in the axial direction of the fixed shaft 22.
Is adopted. By lengthening the piston 132 in this way, the cylinder volume is increased, and the compression capacity can be increased. In this embodiment, since the length of the piston is long, when the coil spring 33 is employed as the elastic member as in the first embodiment, it is necessary to arrange a plurality of the coil springs at the tip of the cylinder.

In the third embodiment, as shown in FIGS. 4 and 5, a plurality of (three in this case) cylinders 31 in the first embodiment are bored in the same radial direction. The cylinders 31 are arranged in series in the axial direction. The cylinders 31 are communicated with each other by communication paths 239 and 240. Therefore, when the rotor 12 rotates, the pistons 32 reciprocate simultaneously by the cam holes 21. In addition, the reciprocating motion of the piston 32 causes the refrigerant gas to pass through the suction passage 35 and the suction valve 36, and further communicates with the two cylinders 31 on the right side in the drawing.
The refrigerant gas is sucked into the cylinder 32 through the cylinder 0. Also,
From the cylinder 32 to the communication paths 239 and 240, the discharge valve 38,
The refrigerant gas is discharged through the discharge passage 37. With this configuration, the compression capacity can be increased a plurality of times (in this case, three times) without increasing the outer diameter of the electric compressor. The same cam surface is used, and the communication passages 239, 2
The structure is simplified because the structure communicates at 40.

In the fourth embodiment, as shown in FIGS. 6 and 7, three cylinders 31 in the first embodiment are bored in the radial direction with a phase shift of 120 degrees around the circumference of the cylinder. In addition, these cylinders 31 are arranged dispersedly in the axial direction,
A piston 32 is housed in each of the cylinders 31. Further, the suction passage 35 for these cylinders 31
As shown in FIG. 7, the discharge passage 38 is provided at each of the bottom positions A, B, and C of the respective cylinders 31 so that the suction valve (not shown) or the discharge passage 38 is provided in the same manner as in the first embodiment. Via a discharge valve (not shown)
The suction chamber 24 and the discharge chamber 25 are individually connected to each other. Accordingly, when the rotor 12 rotates, the suction compression action is performed by the cam holes 21 at positions where the pistons 32 are out of phase by 120 degrees, so that the load balance in the radial direction is improved. Further, since the compression cycle is performed three times per one rotation of the rotor 12, the compression capacity is increased multiple times (in this case, three times) without increasing the outer diameter of the electric compressor as in the third embodiment. It can be.

Next, in the fifth and sixth embodiments, the cam hole 21 in the first embodiment is changed to a cam hole having a plurality of cam surfaces, and the rotor 12 is rotated once. This is such that the piston 32 is reciprocated a plurality of times.

In the fifth embodiment, as shown in FIG. 8, a cam hole 221 having two cam surfaces 221a and 221b is formed. In this case, the piston 32 is
Each time it rotates, it comes into contact with the respective cam surfaces 221a, 221b once and reciprocates, and one compression cycle is performed on each cam surface. Accordingly, one rotation of the rotor 12 causes the piston 32 to reciprocate twice, and two compression cycles are performed. For this reason, the compression capacity can be doubled without increasing the outer diameter of the electric compressor.

In the sixth embodiment, as shown in FIG. 9, a cam hole 321 having three cam surfaces 321a, 321b, 321c is formed. In this case, each time the rotor 12 makes one revolution, the piston 32 moves the cam surface 321a,
321b and 321c are brought into contact once and reciprocated, and one compression cycle is performed on each cam surface. Therefore, one rotation of the rotor 12 causes the piston 32 to reciprocate three times, and three compression cycles are performed. For this reason,
Without increasing the outer diameter of the electric compressor, the compression capacity
Can be doubled.

[0026]

Since the present invention is configured as described above, the following effects can be obtained. According to the first to fourth aspects of the present invention, since the compression mechanism is completely integrally formed in the electric motor, the space is saved and the weight is reduced. In the field of compressors for vehicle air conditioners, the number of rotations of an electric compressor is about 3 to more than that of an engine driven compressor.
Since the cylinder volume is increased by about 10 times, the cylinder volume may be small, and it is easy to adopt such a configuration.

According to the second aspect of the invention, in addition to the above effects, the compression capacity can be increased in accordance with the number of cylinders and pistons without increasing the external dimensions of the electric compressor. According to the third aspect of the present invention, in addition to the above effects, the cam hole and the fixed shaft have a circular cross-sectional shape, which facilitates manufacture. According to the fourth aspect of the present invention, in addition to the above effects, the piston is reciprocated a plurality of times each time the rotor is rotated once by the plurality of cam surfaces, so that the compression capacity can be doubled. it can. According to the fifth aspect of the present invention, in addition to the above-described effects, since carbon dioxide is used as the refrigerant, the capacity is reduced and the compression mechanism is reduced in size. It becomes easier to adopt.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an electric compressor according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a perspective view illustrating a compression mechanism according to a second embodiment of the present invention.

FIG. 4 is a perspective view showing a compression mechanism portion according to a third embodiment of the present invention.

FIG. 5 is a side sectional view of a compression mechanism portion of an electric compressor according to a third embodiment of the present invention.

FIG. 6 is a perspective view showing a compression mechanism portion according to a fourth embodiment of the present invention.

FIG. 7 is a front sectional view showing a compression mechanism portion according to a fourth embodiment of the present invention.

FIG. 8 is a front sectional view showing a compression mechanism portion according to a fifth embodiment of the present invention.

FIG. 9 is a front sectional view showing a compression mechanism according to a sixth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Closed container, 2 ... Container main body, 2a ... Side wall of container main body,
2b: annular protrusion, 3: cover plate, 10: electric motor, 11
... stator, 12 ... rotor, 13 ... bearing, 14 ... terminal, 1
5 thrust bearings, 21, 221, 321 cam holes, 2
1a, 221a, 221b, 321a, 321b, 32
1c: cam surface, 22: fixed shaft, 23: suction hole, 24: suction chamber, 25: discharge chamber, 26: discharge hole, 27: seat plate, 31
... cylinder, 32, 132 ... piston, 33 ... elastic member, 35 ... suction passage, 36 ... suction valve, 37 ... discharge passage,
38: discharge valve, 239, 240: communication passage.

Claims (5)

[Claims] An electric motor having a sealed container, a stator, a rotor, and the like built in the sealed container, and a cam hole having a cam surface disposed at a center portion of the rotor in a central axis direction. A fixed shaft arranged in the center axis direction of the cam hole and fixed to the closed container, and a cylinder drilled in a radial direction of the fixed shaft and having one end opened to the outer peripheral surface of the fixed shaft; A piston that is slidably and reciprocally housed in the cylinder, and further has an outer end surface slidably in contact with the cam surface, and is reciprocally moved by the cam surface as the rotor rotates. A suction passage formed at one end of the fixed shaft so as to communicate with the cylinder via a suction valve; and a suction passage formed at the other end of the fixed shaft so as to communicate with the cylinder via a discharge valve. An electric compressor comprising: a discharge passage; 2. The electric compressor according to claim 1, wherein a plurality of cylinders and pistons are provided on the fixed shaft in an axial direction of the fixed shaft. 3. The fixed shaft has a circular cross section,
2. The electric compressor according to claim 1, wherein the cam hole has a circular cross section and is eccentric with respect to a center axis of the rotor. 4. The fixed shaft has a circular cross section,
The cam hole is formed so that a cross-sectional shape forms a plurality of cam surfaces, and the piston is reciprocated a plurality of times by the plurality of cam surfaces each time the rotor makes one rotation. The electric compressor according to claim 1. 5. The electric compressor according to claim 1, wherein the refrigerant used is carbon dioxide.