JP2009293589A - Electric compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an efficient and reliable electric compressor capable of suppressing reduction in motor efficiency while reducing sliding loss. <P>SOLUTION: The electric compressor 50 comprises a motor 7 composed of a rotor 7a housing a permanent magnet and a stator 7b, a compressing mechanism part 2 for compressing working fluid, and a crank shaft 6 fixed to the rotor 7a and connected to the compressing mechanism part 2. The crank shaft 6 is held so as not to have at all any sliding part to the thrust direction during normal operation. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electric compressor, and is particularly suitable for an electric compressor used in a refrigeration air conditioner or the like.

  As a conventional scroll compressor, one described in Japanese Patent Laid-Open No. 60-75795 (Patent Document 1) is known.

  The scroll compression device of Patent Document 1 includes a compression mechanism in which a fixed element is positioned on the upper side and a movable element is positioned on the lower side in a sealed container, and a motor that is provided below the compression mechanism and drives the compression mechanism. And a rotating shaft for transmitting the rotational force of the electric motor to the compression mechanism. The motor is constituted by a squirrel-cage induction motor, and is configured such that the magnetic center of the rotor is shifted downward with respect to the magnetic center of the stator. When power is supplied to the motor, an upward magnetic force always acts on the rotor so that the magnetic center of the stator and the magnetic center of the rotor coincide with each other, and an upward thrust is applied to the movable element via the rotating shaft. Added. As a result, the downward thrust force applied to the movable element is reduced.

JP-A-60-75795

  However, in the scroll compressor of Patent Document 1, the downward thrust force of the movable element is reduced. However, since there is sliding in the thrust direction between the rotating shaft and the movable element, it is caused by the sliding of the part. There is a risk of reducing performance and reducing reliability such as wear and seizure.

  An object of the present invention is to obtain a highly efficient and highly reliable electric compressor by suppressing a decrease in electric motor efficiency and reducing sliding loss.

  In order to achieve the above-mentioned object, in the present invention, an electric motor including a rotor and a stator with a built-in permanent magnet, a compression mechanism portion that compresses a working fluid, a rotor that is fixed to the rotor of the electric motor, and the compression mechanism portion. An electric compressor provided with a connected crankshaft, wherein the crankshaft is held so as not to have any sliding portion in the thrust direction during normal operation.

A more preferable specific configuration example of the present invention is as follows.
(1) A neodymium magnet is used as the permanent magnet.
(2) A support member that suppresses the crankshaft from moving more than a predetermined distance in the thrust direction is provided.
(3) In (2), the support member is held on the compression mechanism portion or the crankshaft via an elastic member.
(4) In the above (2), the support member is formed of a flange portion formed on a neck portion of the crankshaft.

  According to the present invention, it is possible to obtain a highly efficient and highly reliable electric compressor by suppressing reduction in electric motor efficiency and reducing sliding loss.

  Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. The same reference numerals in the drawings of the respective embodiments indicate the same or equivalent.

(First embodiment)
A hermetic scroll electric compressor according to a first embodiment of the present invention will be described with reference to FIGS. 1 is a longitudinal sectional view of the scroll electric compressor of the present embodiment, FIG. 2 is a sectional view showing the vicinity of the upper end portion of the crankshaft of the scroll electric compressor of FIG. 1, and FIG. 3 is a crank of the scroll electric compressor of FIG. 4 is a cross-sectional view showing the vicinity of the lower end portion of the shaft, and FIG. 4 is a cross-sectional view showing the vicinity of the electric motor of the scroll electric compressor of FIG.

  As shown in FIG. 1, the scroll electric compressor 50 is configured by storing the compression mechanism 2 and the electric motor 7 in the sealed container 1. The compression mechanism 2 is configured by housing a turning scroll 4 that meshes with the fixed scroll between a frame 5 fixed to the hermetic container 1 and a fixed scroll 3 bolted on the frame 5. The orbiting scroll 4 is supported so as to be orbitable via a rotation prevention mechanism such as the Oldham ring 10. The orbiting scroll 4 is eccentrically driven by a pin portion 6 a at the end of the crankshaft 6. When the orbiting scroll 4 is driven, the compression chamber 17 formed with the fixed scroll 3 is gradually reduced, the working fluid flowing in from the suction pipe 11 and the suction port 12 is compressed, and the central portion of the fixed scroll 3 is compressed. The working fluid is discharged into the sealed container 1 from the discharge port 14.

  The fixed scroll 3 is provided with a back pressure hole 8 that allows the compression chamber 17 and the back pressure chamber 13 on the back of the orbiting scroll 4 to communicate with each other. As a result, the working fluid in the compression chamber 17 in the middle of compression is guided to the back pressure chamber 13, and the pressure in the back pressure chamber 13 is maintained at an intermediate pressure (intermediate pressure) between the suction pressure and the discharge pressure. Here, the back pressure chamber 13 formed on the back surface of the orbiting scroll 4 is a space formed by being surrounded by the orbiting scroll 4, the frame 5, and the fixed scroll 3.

  The crankshaft 6 is supported in the radial direction by the main bearing 5a disposed in the frame 5 and the auxiliary bearing member 15 fixed in the sealed container 1, and can rotate stably.

  The electric motor 7 is located between the frame 5 and the auxiliary bearing member 15, and is a synchronous electric motor constituted by a stator 7 b fixed to the sealed container 1 and a rotor 7 a fixed to the crankshaft 6. The electric motor 7 transmits the rotation of the rotor 7 a to the orbiting scroll 4 by the crankshaft 6 and drives the compression mechanism 2. Balance weights 16 fixed by pins are provided on the upper and lower end surfaces of the rotor 7a. As a result, the rotor 7a and the crankshaft 6 rotate stably, and the orbiting scroll 4 can be stably moved in a circular orbit. Note that a neodymium magnet is incorporated in the rotor 7a of the present embodiment.

  The lower end of the crankshaft 6 reaches the oil sump 9 at the bottom of the sealed container 1, and the oil in the oil sump 9 is driven by the differential pressure between the discharge pressure in the sealed container 1 and the intermediate pressure in the back pressure chamber 13. It is lifted through the oil supply path 6b that passes therethrough, and supplied to the sliding portions of the auxiliary bearing member 15, the main bearing 5a, and the compression mechanism 2 to enhance their lubricity and sealing performance.

  Each end surface of the pin portion 6a and the neck portion 6c of the crankshaft 6 does not have any sliding surface in the thrust direction as shown in FIGS. That is, the neck 6c of the crankshaft 6 is thinner than the pin 6a and the main trunk 6d. Further, the end surface 6e of the main trunk portion 6d of the crankshaft 6 does not have any sliding surface in the thrust direction as shown in FIG. Accordingly, the crankshaft 6 has no sliding portion in the thrust direction. In such a configuration, the thrust load caused by the magnetic thrust generated by the self-weight of the crankshaft 6 and the rotor 7a and the balance weight 16 fastened to the crankshaft 6 and the deviation of the magnet center between the rotor 7a and the stator 7b is applied everywhere. Not.

  The dead weight of the crankshaft 6 and the rotor 7a acts downward as indicated by the black arrow in FIG. 4, but the magnetic thrust generated by the deviation of the magnet center between the rotor 7a and the stator 7b is upward as indicated by the hatched arrow in FIG. The crankshaft 6 and the rotor 7a are held at a position where they are balanced. That is, the crankshaft 6 is not restricted in the thrust direction with respect to the direction in which the magnetic thrust acts, and the rotor 7a is movable. Therefore, the rotor 7a and the magnet center of the stator 7b are fastened to the crankshaft 6 and the crankshaft. And the weight of the balance weight and the like, and the magnetic thrust generated by the deviation between the stator 7a and the rotor 7b of the electric motor 7 are automatically adjusted to a balance position.

  According to the present embodiment, the magnet center of the rotor 7a and the magnet center of the stator 7b during operation are set appropriately by the magnetic thrust, and a reduction in the efficiency of the electric motor 7 can be suppressed. Furthermore, since the sliding loss due to the thrust force can be eliminated, the performance of the compressor can be improved. Moreover, since a sliding location can be reduced, reliability can be improved. Therefore, a highly efficient and highly reliable electric compressor can be obtained.

  When the present invention is applied to a horizontal electric motor compressor, the self-weights of the crankshaft 6 and the rotor 7a do not act in the thrust direction, so that the magnet centers of the rotor 7a and the stator 7b can always be matched.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a longitudinal sectional view of a scroll electric compressor according to the second embodiment of the present invention. The second embodiment is different from the first embodiment in the points described below, and the other points are basically the same as those in the first embodiment, and thus redundant description is omitted.

  In the second embodiment, the neck portion 6c of the crankshaft 6 has a flange portion 6c1 larger than the pin portion 6a and the main trunk portion 6d. By using this flange portion 6c1 for positioning during assembly, the assembly can be facilitated. This is particularly effective when the neodymium magnet provided in the rotor 7a is magnetized after assembly. The flange portion 6c1 does not constitute a sliding surface with respect to the thrust direction during normal operation.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 6 is a cross-sectional view showing the vicinity of the upper end portion of the crankshaft of the scroll electric compressor according to the third embodiment of the present invention. The third embodiment is different from the first embodiment in the points described below, and the other points are basically the same as those in the first embodiment, and thus redundant description is omitted.

  In the third embodiment, a support member 18 is provided to suppress the movement of the crankshaft 6 when it moves in the thrust direction. The support member 18 is held by the orbiting scroll 4 via a coil spring 18a. As a result, the deviation of the magnet center between the rotor 7a and the stator 7b is kept in a very small range, and even if the movement to the crankshaft 6 is attempted, the end surface of the pin portion 6a of the crankshaft 6 collides with the support member 18. Thus, the impact and sliding generated in the thrust direction can be reduced by the support member 18 and the coil spring 18a.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a cross-sectional view showing the vicinity of the upper end of a part of the crankshaft of the scroll electric compressor according to the fourth embodiment of the present invention. The fourth embodiment is different from the second embodiment in the following points, and the other points are basically the same as those in the second embodiment, and thus redundant description is omitted.

  In this 4th Embodiment, when the crankshaft 6 moves to a thrust direction, the support member 19 which suppresses the movement is provided. The support member 19 is held by the main shaft portion 6d of the crankshaft via a coil spring 19a. As a result, the deviation of the magnet center between the rotor 7a and the stator 7b is kept within a minute range, and even if the crankshaft 6 is to move greatly, the end surface of the support member 19 is the flange portion 6c1 of the neck portion 6c of the crankshaft 6. The impact and sliding generated in the thrust direction can be reduced by the support member 19 and the coil spring 19a.

(Other embodiments)
Each of the above-described embodiments has been described by taking a hermetic scroll electric compressor as an example. However, the present invention can be configured without being a hermetic type, and can be applied to a rotary compressor or the like.

It is a longitudinal cross-sectional view of the scroll electric compressor of 1st Embodiment of this invention. It is sectional drawing which shows the upper end part vicinity of the crankshaft of the scroll electric compressor of FIG. It is sectional drawing which shows the lower end part vicinity of the crankshaft of the scroll electric compressor of FIG. It is sectional drawing which shows the electric motor vicinity of the scroll electric compressor of FIG. It is a longitudinal cross-sectional view of the scroll electric compressor of 2nd Embodiment of this invention. It is sectional drawing which shows the upper end part vicinity of the crankshaft of the scroll electric compressor of 3rd Embodiment of this invention. It is sectional drawing which shows the upper end part vicinity of the one part crankshaft of the scroll electric compressor of 4th Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Airtight container, 2 ... Compression mechanism, 3 ... Fixed scroll, 4 ... Orbiting scroll, 5 ... Frame, 5a ... Bearing part, 6 ... Crankshaft, 6a ... Pin part, 6b ... Oil supply hole, 6c ... Neck part, 6c1 ... Flange part, 6d ... Main trunk part, 6e ... Main trunk lower end surface, 7 ... Electric motor, 7a ... Rotor, 7b ... Stator, 8 ... Back pressure hole, 9 ... Oil sump, 10 ... Oldham ring, 11 ... Suction pipe, 12 ... Suction Mouth, 13 ... back pressure chamber, 14 ... discharge port, 15 ... sub-bearing member, 16 ... balance weight, 17 ... compression chamber, 18 ... support member, 18a ... coil spring, 19 ... support member, 19a ... coil spring, 50 ... electric Compressor.

Claims (5)

An electric motor comprising a rotor and a stator with a built-in permanent magnet;
A compression mechanism for compressing the working fluid;
An electric compressor including a crankshaft fixed to the rotor of the electric motor and coupled to the compression mechanism unit,
The electric compressor according to claim 1, wherein the crankshaft is held so as not to have any sliding portion in the thrust direction during normal operation.   2. The electric compressor according to claim 1, wherein a neodymium magnet is used as the permanent magnet.   2. The electric compressor according to claim 1, further comprising a support member that suppresses the crankshaft from moving more than a predetermined distance in the thrust direction.   4. The electric compressor according to claim 3, wherein the support member is held by the compression mechanism portion or the crankshaft via an elastic member.   4. The electric compressor according to claim 3, wherein the support member is formed by a flange portion formed at a neck portion of the crankshaft.

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