Electric compressor

Abstract

[Problem] To provide an electric compressor that can improve sealing performance by keeping a sealing material from falling off during the shrink-fitting of a stator and that can also stabilize the force with which the stator is held by the shrink-fitting. [Solution] An electric compressor 10 comprises a cylindrical motor case 11 that accommodates a motor 30 that has been inserted through an opening 111. A shrink-fitting part 50 for the shrink-fitting of a stator 32 of the motor 30 is formed at an inner circumferential surface of the motor case 11. A rib 51 that is connected to the shrink-fitting part 50 and extends along the axial direction of the motor case 11 from the shrink-fitting part 50 to the opening 111 is also formed at the inner circumferential surface of the motor case 11.

Description

Electric compressor

[0001] The present invention relates to an electric compressor.

[0002] A technique for shrink-fitting a motor stator during assembly of an electric compressor is disclosed (for example, Patent Documents 1 and 2).

[0003] Japanese Patent No. 6400389 Japanese Unexamined Patent Application Publication No. 2024-096042

[0004] It is an object of the present invention to provide an electric compressor that can improve sealing performance by preventing a sealing material from falling off when shrink-fitting a stator, and can stabilize the holding force of the stator by shrink-fitting.

[0005] According to one aspect of the present invention, there is provided an electric compressor comprising a cylindrical motor case that houses a motor inserted through an opening, wherein a shrink-fitting portion for shrink-fitting the stator of the motor is formed on an inner circumferential surface of the motor case, wherein a rib that is continuous with the shrink-fitting portion and extends from the shrink-fitting portion to the opening along the axial direction of the motor case is formed on the inner circumferential surface of the motor case.

[0006] According to the present invention, there can be provided an electric compressor that can improve sealing performance by preventing a sealing material from falling off when shrink-fitting a stator, and can stabilize the holding force of the stator by shrink-fitting.

[0007] FIG. 1 is a cross-sectional view showing an electric compressor according to an embodiment of the present invention. FIG. 2 is a perspective view of an electric compressor according to an embodiment of the present invention. FIG. 3 is a vertical cross-sectional view of a motor case. FIG. 4 is a plan view of the motor case.

[0008] Hereinafter, an electric compressor 10 according to an embodiment of the present invention will be described with reference to the drawings.

[0009] As shown in FIGS. 1 and 2, the electric compressor 10 is used in a refrigerant circuit or the like of a vehicle air conditioner. The electric compressor 10 is a compressor that sucks in and compresses a working fluid such as a refrigerant circulating in the refrigerant circuit of the air conditioner, and discharges the compressed fluid to a discharge pipe. The electric compressor 10 is a horizontal inverter-integrated scroll-type electric compressor.

[0010] The electric compressor 10 comprises a compression mechanism 20, a motor 30, and an inverter 40. The compression mechanism 20 compresses the working fluid by the movement of a movable member 22 relative to a fixed member 21. For example, the working fluid is compressed by the orbital motion of a movable scroll member, which is the movable member 22, relative to a fixed scroll member, which is the fixed member 21. The motor 30 drives the compression mechanism 20. The inverter 40 converts the DC current from the vehicle's battery into a three-phase AC current and supplies it to the motor 30.

[0011] The electric compressor 10 comprises a cylindrical motor case 11 that houses the motor 30, a cylindrical compression mechanism case 12 that houses the compression mechanism 20, and an inverter case 13 that houses the inverter 40.

[0012] The compression mechanism case 12 is attached to one end of the motor case 11, and the inverter case 13 is attached to the other end of the motor case 11. The motor case 11 and the compression mechanism case 12 are fastened together by a plurality of bolts 15 along the axial direction of the motor case 11 via a sealing material 14. Examples of sealing materials include packing and gaskets.

[0013] The motor 30 comprises a rotor 31, a stator 32, and a rotating shaft 33. The rotor 31 rotates integrally with the rotating shaft 33. The motor 30 is inserted through an opening 111 at one end of the motor case 11 and housed inside the motor case 11. The motor 30 is fixed to the motor case 11 by shrink-fitting the stator 32.

[0014] As shown in Figures 3 and 4, the inner circumferential surface of the motor case 11 has a plurality of shrink-fit portions 50 for shrink-fitting the stator 32 of the motor 30. The shrink-fit portions 50 are arranged at predetermined intervals along the circumferential direction of the motor case 11. The shrink-fit portions 50 protrude inward from the motor case 11. The length of the shrink-fit portions 50 along the axial direction of the motor case 11 is longer than the width along the circumferential direction of the motor case 11. The length of the shrink-fit portions 50 along the axial direction of the motor case 11 is approximately the same as the length along the axial direction of the stator 32. In addition, the surface of the shrink-fit portions 50 is shaped to conform to the surface of the stator 32. When the motor 30 is housed in the motor case 11, the surface of the shrink-fit portions 50 comes into contact with the surface of the stator 32.

[0015] A rib 51 is formed on the inner circumferential surface of the motor case 11, which is connected to the shrink-fit portion 50 and extends from the shrink-fit portion 50 to the opening 111 along the axial direction of the motor case 11. The rib 51 extends from a part of the width of the shrink-fit portion 50 along the circumferential direction of the motor case 11. The rib 51 has a chamfered portion 511 at its tip. Multiple insertion holes 16 for inserting bolts 15 are formed in the motor case 11. The insertion holes 16 extend along the axial direction of the motor case 11. Due to the bulge of the wall surface surrounding the insertion holes 16 on the inner circumferential surface of the motor case 11, the area around the insertion holes 16 protrudes inward from the motor case 11. The rib 51 is positioned such that its position along the circumferential direction of the motor case 11 is between the insertion holes 16. It is preferable to position the rib 51 in an intermediate portion equidistant from two of the insertion holes 16.

[0016] The ribs 51 are formed in four locations. The ribs 51 are positioned so that there is one in each of the four regions obtained by dividing the opening 111 at 90-degree intervals.

[0017] When assembling the electric compressor 10 configured as described above, the motor 30 is housed in the motor case 11 by inserting it through the opening 111 of the motor case 11. At this time, since the tip of the rib 51 is provided with a chamfered portion 511, interference between the rib 51 and the stator 32 can be prevented. Therefore, the motor 30 can be inserted smoothly, improving the ease of assembly of the electric compressor 10. After inserting the motor 30 into the motor case 11, the motor 30 is fixed inside the motor case 11 by shrink-fitting the stator 32 with the shrink-fit portion 50.

[0018] In this embodiment, the ribs 51 increase the rigidity of the opening 111 of the motor case 11, so deformation of the opening 111 when shrink-fitting the stator 32 can be suppressed with a simple structure without changing the outer surface of the motor case 11 to a complex shape. Therefore, the detachment of the sealing material 14 due to deformation of the opening 111 can be prevented with a simple structure. As a result, refrigerant leakage due to the detachment of the sealing material 14 can be prevented, and the reliability of the sealing performance can be improved. In addition, since the deformation of the motor case 11 can be suppressed by the ribs 51, the holding force of the stator 32 can be stabilized. Thus, the reliability of holding the stator 32 can be improved.

[0019] Furthermore, since the rib 51 extends from a portion of the width of the shrink-fit portion 50, compared to the case where the shrink-fit portion 50 is extended to the opening 111 to ensure the rigidity of the motor case 11, it is possible to reduce the amount of interference between the motor 30 and the stator 32 when inserting the motor 30 into the motor case 11. Therefore, it is possible to make it easier to insert the motor 30 into the motor case 11.

[0020] Furthermore, if the ribs 51 were provided on the wall surface surrounding the insertion holes 16 of the motor case 11, the motor case 11 would have to be enlarged to secure space for inserting the stator 32. However, by arranging the ribs 51 along the circumferential direction of the motor case 11 between the insertion holes 16, it is possible to prevent the motor case 11 from becoming larger.

[0021] Furthermore, by arranging the ribs 51 so that there is one in each of the four regions obtained by dividing the opening 111 at 90-degree intervals, it becomes possible to deform the opening 111 evenly, thereby preventing the sealing material 14 from falling out and improving the reliability of holding the stator 32.

[0022] Furthermore, it is preferable to form a tapered surface on the surface of the rib 51 that slopes outward along the axis of the motor case 11 so as to widen the opening 111, or to form a step on the surface of the rib 51 by making the tip of the rib 51 thinner so as to widen the opening 111. This allows the stator 32 to be guided into the inside of the motor case 11 by the slope or step on the surface of the rib 51, so that the motor 30 can be inserted smoothly.

[0023] [Effects of this embodiment] (1) The electric compressor 10 is provided with a cylindrical motor case 11 that houses a motor 30 inserted through an opening 111, and a shrink-fit portion 50 for shrink-fitting the stator 32 of the motor 30 is formed on the inner circumferential surface of the motor case 11, wherein a rib 51 is formed on the inner circumferential surface of the motor case 11 that is connected to the shrink-fit portion 50 and extends from the shrink-fit portion 50 to the opening 111 along the axial direction of the motor case 11. Therefore, deformation of the opening 111 when shrink-fitting the stator 32 can be suppressed with a simple structure without changing the outer circumferential surface of the motor case 11 to a complex shape. As a result, the detachment of the sealing material 14 due to deformation of the opening 111 can be prevented with a simple structure. Furthermore, by preventing the detachment of the sealing material 14, the sealing performance can be improved. In addition, by suppressing the deformation of the opening 111, the holding force of the stator 32 by shrink-fitting can be stabilized.

[0024] (2) The rib 51 extends from a part of the width of the shrink-fit portion 50 along the circumferential direction of the motor case 11. Therefore, compared to the case in which the shrink-fit portion 50 is extended to ensure the rigidity of the motor case 11, the amount of interference with the stator 32 can be reduced, making it easier to insert the motor 30 into the motor case 11.

[0025] (3) The motor case 11 and the case 12 other than the motor case 11 are fastened together with a plurality of bolts 15 along the axial direction of the motor case 11, and a plurality of insertion holes 16 for inserting the bolts 15 are formed in the motor case 11, and the inner circumferential surface of the motor case 11 protrudes inward around the insertion holes 16, and the ribs 15 are positioned so that their positions along the circumferential direction of the motor case 11 are between the insertion holes 16. Therefore, it is possible to prevent the motor case 11 from becoming larger compared to the case in which the ribs 51 are provided on the wall surface around the insertion holes 16 of the motor case 11.

[0026] Although the present invention has been described above with reference to preferred embodiments, it goes without saying that the present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the present invention.

[0027] 10: Electric compressor 11: Motor case 12: Compression mechanism case 13: Inverter case 14: Sealing material 15: Bolt 16: Insertion hole 40: Inverter 50: Shrink-fit part 51: Rib 511: Chamfered part 111: Opening

Claims

1. An electric compressor comprising a cylindrical motor case for housing a motor inserted through an opening, wherein a shrink-fit portion for shrink-fitting the stator of the motor is formed on the inner circumferential surface of the motor case, characterized in that a rib is formed on the inner circumferential surface of the motor case that is connected to the shrink-fit portion and extends from the shrink-fit portion to the opening along the axial direction of the motor case.

2. The electric compressor according to claim 1, characterized in that the rib extends from a part of the width of the shrink-fit portion along the circumferential direction of the motor case.

3. The electric compressor according to claim 1, characterized in that the motor case and a case other than the motor case are fastened together by a plurality of bolts along the axial direction of the motor case, a plurality of insertion holes for inserting the bolts are formed in the motor case, the inner circumferential surface of the motor case protrudes inward from the insertion holes, and the ribs are positioned such that their positions along the circumferential direction of the motor case are between the insertion holes.

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