JP2012013030A - Electric compressor - Google Patents

Abstract

A compact, lightweight, and efficient electric compressor is provided that prevents the generation of a gap that is likely to occur due to the difference in thermal expansion coefficient between an electric motor and a main body casing, and the expansion of a shimishi during an interference fit.
An annular fixing member (7a, 7b) fixed to an end surface of a stator (5a) of an electric motor (5) is provided, and an outer peripheral contact surface of the fixing member (7a, 7b) is directly fixed to an inner periphery of the main casing (1) by a fastening means. The fixing members 7a and 7b, which are materials having a larger thermal expansion coefficient than the stator 5a of the electric motor 5, are formed into the main body casing 1 and the stator 5a of the electric motor 5 by the structure that is fastened through the fixing members 7a and 7b. The internal stress generated in the main body casing 1 and the stator 5a is relieved because the thermal expansion amount difference is absorbed and stress is absorbed by the elastic deformation of the fixing members 7a and 7b. As a result, the main body casing becomes small and thin, and it becomes a fastening means for the stator of the motor that is excellent in reliability without deteriorating the efficiency of the motor.
[Selection] Figure 1

Description

  The present invention relates to an electric compressor used for a refrigerant compressor such as an air conditioner for vehicle air conditioning.

  Conventionally, this type of electric compressor has been proposed in which an iron motor stator is directly shrink-fitted on an aluminum shell (see, for example, Patent Document 1). In some cases, the outer wall is deformed by applying an external force to the non-circular shell and the stator is inserted, and then the external force is released to fix the motor stator (see, for example, Patent Document 2). Furthermore, a structure in which a fixing member made of a material having a larger thermal expansion coefficient than that of the stator and the shell is engaged with the end face of the stator in the radial direction and is fixed by bolts by being sandwiched by the shell in the axial direction. (For example, refer to Patent Document 3).

  FIG. 7 shows a conventional electric compressor described in Patent Document 3. As shown in FIG. As shown in FIG. 7, the compressor main body 101 formed in a hollow shape, a compression unit (not shown) that compresses the fluid sucked into the compressor main body 101, a motor 102 that drives the compression unit, and a compression It is made of a material having a higher thermal expansion coefficient than the machine main body 101 and the motor 102, and includes two fixing members 103 for fixing the motor 102 at predetermined positions in the circumferential direction. The compressor main body 101 is divided into 101a and 102b, and the two Two fixing members 103 are sandwiched from the axial direction and fixed with bolts 104.

JP-A-9-287585 JP 2004-332614 A JP 2003-343438 A

  However, as a problem of the conventional configuration, in the examples shown in Patent Documents 1 and 2, since the motor stator itself is shrink-fitted and fixed, the laminated plate of the motor 3 is deformed by a force generated by shrink-fitting or external force deformation. As a result, the efficiency of the motor may deteriorate, or the compressor body (shell) may be damaged, and it is difficult to reduce the thickness of the shell. In addition, in the case of Patent Document 3, the fixing member 103 needs to be divided into two parts of the compressor main body 101 and fastened with bolts, so that the fastening portion protrudes, and a sealing material and a plurality of bolts are necessary. There was a problem that there were harmful effects.

  The present invention solves the above-mentioned conventional problems, eliminates the need for expansion of the compressor body (shell) and the need for a sealing material, and prevents deterioration of the efficiency of the motor and increase in the thickness of the shell. An object is to provide a lightweight and highly reliable electric compressor.

  In order to solve the conventional problems, an electric compressor of the present invention includes a compression unit that performs suction, compression, and discharge of fluid, an electric motor that drives the compression unit, the compression unit, and the electric motor. A main body casing made of a metal material having a larger thermal expansion coefficient than the stator of the electric motor, and an annular fixing member fixed to an end face of the stator of the electric motor, wherein the fixing member has a thermal expansion coefficient higher than that of the stator of the electric motor. The outer peripheral contact surface of the fixing member is directly fixed to the inner periphery of the main body casing by a fastening means.

  As a result, when the motor and the main casing are in a high temperature state, the contact surface between the outer periphery of the fixing member fixed to the end surface of the motor and the inner periphery of the main casing is fastened in the radial direction, thereby fixing the motor. The generation of a gap due to the difference in thermal expansion between the constituent material of the child and the main body casing is suppressed, and the electric motor stator is fixed via the fixing member, so that the stress on the electric motor stator can be reduced.

  In the electric compressor of the present invention, the laminate generated by the stator of the electric motor is deformed by stress generated by shrink fitting into the main body casing of the electric motor and the efficiency of the electric motor is deteriorated, or the main body casing is damaged. The electric compressor can be fixed and fastened to the main body casing without increasing the outer diameter and wall thickness of the main body casing, making it a compact, lightweight, efficient and highly reliable electric compressor. Can do.

Sectional view in the axial direction of the electric compressor according to the first embodiment of the present invention. Horizontal plan view of the fixing member in the first embodiment Explanatory drawing which shows fixation of the fixing member in the same Embodiment 1. (A) (b) It is a figure which shows fixation of the fixing member of the electric compressor in Embodiment 2 of this invention, (a) is a horizontal plane view at the time of insertion of an electric motor, (b) is a horizontal plane after rotation press-fitting. Figure Horizontal plan view of a fixing member in Embodiment 3 of the present invention (A) (b) It is a figure which shows fastening of the fixing member in Embodiment 3, (a) is an axial sectional view, (b) is a horizontal plan view Axial cross-sectional view explaining motor fixing of a conventional electric compressor

  A first aspect of the present invention is a metal having a compression unit that sucks, compresses and discharges a fluid, an electric motor that drives the compression unit, the compression unit and the electric motor, and has a larger thermal expansion coefficient than a stator of the electric motor. A main body casing made of a material, and an annular fixing member fixed to an end face of the stator of the electric motor, wherein the fixing member is a material having a larger coefficient of thermal expansion than the stator of the electric motor, and the fixing member The outer peripheral contact surface is directly fixed to the inner periphery of the main casing by fastening means. As a result, when the electric motor or the main body casing is in a high temperature state, the outer surface of the fixing member fixed to the end surface of the electric motor and the inner peripheral contact surface of the main body casing are fastened in the radial direction, thereby fixing the electric motor stator and the main body. It is possible to suppress the generation of gaps due to the difference in thermal expansion of the constituent material from the casing, and to relieve stress between the main casing and the stator of the motor at the time of fastening, without increasing the outer diameter and thickness of the main casing. The main body casing can be fixed and fastened, and the electric compressor can be made small, light, efficient and highly reliable.

  In the second invention, in particular, the fixing member of the first invention and the stator of the motor are fastened by a plurality of fastening members, and the inner periphery of the main body casing and the outer periphery of the fixing member are sandwiched between the adjacent fastening members. At the contact surface on the circumference of the position, the main body casing is fixed by shrinkage fitting, either the shrink fitting of the fixing member, the cold fitting of the fixing member, or the elastic casing using the elastic deformation by the external force of the main casing or the fixing member. , The stress relaxation of the main casing and the motor stator at the time of tightening is possible compared to the past, and the motor and main casing can be fixed and fastened without increasing the outer diameter and thickness of the main casing, A compact, lightweight, efficient and highly reliable electric compressor can be obtained.

According to a third aspect of the present invention, a plurality of concave portions are formed in the outer peripheral portion of the fixing member of the first invention and the stator of the electric motor, and a concave portion having an outer diameter larger than the outer diameter of the fixing member is formed in the inner peripheral portion of the main body casing. And an electric compressor fixed by rotating and press-fitting the outer peripheral portion of the fixing member into the inner peripheral portion of the main body casing, and the structure that can relieve the stress of the stator of the electric motor during press-fitting Therefore, the electric compressor can be made efficient and highly reliable.

  In a fourth invention, the fixing member of the first invention is a metal material having a larger coefficient of thermal expansion than the stator of the electric motor, the fixing member and the stator of the electric motor are fastened by a plurality of fastening members, and the main body The inner circumference of the casing and the outer circumference of the fixing member are fixed by welding at a circumferential contact surface sandwiched between the adjacent fastening members. The structure that can relieve the stress of the stator allows the motor and the main casing to be fixed and fastened without increasing the outer diameter and thickness of the main casing, and is small, lightweight, efficient, and reliable. A highly efficient electric compressor can be obtained.

  In the fifth invention, the fixing member of the fourth invention is made of the same metal material as that of the main body casing, and the structure is excellent in weldability and the same effect can be expected.

  In the sixth invention, the same metal material of the fifth invention is an alloy containing aluminum or magnesium or both as a main component, and the structure is small and light and has excellent weldability. it can.

  In the seventh invention, the fixing member of the fourth, fifth, and sixth inventions has a configuration in which a non-conductive film is applied to a location where the winding of the electric motor is close, and the winding property to the stator of the electric motor is improved. An excellent fixing member having insulating properties can be obtained, and similar effects can be expected.

  In the eighth invention, in particular, a gas passage is formed in the fixing member of any one of the first to seventh inventions, and the stator of the motor is promoted to be cooled by the refrigerant gas, An electric compressor having high efficiency and high reliability can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is an axial cross-sectional view showing the overall structure of the electric compressor according to the first embodiment of the present invention.

  In FIG. 1, a main casing 1 is a main casing formed in a substantially bottomed cylindrical shape having an opening on the right side in FIG. 1, and is formed of aluminum or the like for weight reduction. Reference numeral 2 denotes a compression unit incorporated in the main body casing 1 from the right opening side, and is sandwiched and fixed by a casing cover 1a. The compression unit 2 has a scroll structure, and the orbiting scroll 4 performs a orbiting motion with respect to the fixed scroll 3 to compress the refrigerant gas from the outer periphery toward the center. The orbiting scroll 4 is driven by a shaft press-fitted into the rotor 6 of the electric motor 5. Fixing members 7a and 7b are disposed on the stator 5a of the electric motor 5 in contact with both end surfaces in the axial direction, and are fixed by a plurality of fastening members 8, such as bolts. The fixing members 7a and 7b are made of a material having a larger thermal expansion coefficient than the stator 5a.

FIG. 2 is a plan view showing a structure for fixing the stator 5a of FIG. The fixing member 7 (7b) a disposed on the end face of the stator 5a (outer periphery 5b) indicated by a one-dot chain line is annular, and is connected to the stator 5a by four fastening members 8. The outer periphery of the fixing member 7a (7b) is provided with a D-cut concave portion 7c serving as a gas passage for cooling the stator 5a, and is located between the two fastening members 8 and the main body casing. The outer peripheral contact surface 7d in contact with one inner peripheral wall is fastened and fixed in the circumferential direction by fastening means described later.

  FIG. 3 illustrates the above fastening means, and an interference fit is used as the fastening means. As an example of the interference fitting, a configuration in the case of shrink fitting is shown. In the figure, reference numeral 10 denotes an induction heater, which shows a state in which the main body casing 1 is induction-heated and the stator 5a installed on the insertion jig 11 is positioned and inserted at a predetermined position in the main body casing 1. This shrinkage fit is achieved by shrinkage due to cooling of the main casing as in the conventional case. However, the fixing member 7a (7b) generates less stress due to press fitting, and the main casing 1 is caused by elastic deformation of the fixing member. Stress relaxation can be expected. Then, no force is applied to the stator 5a, and there is no fear of deformation of the stator 5a. Moreover, since it is not what is fixed so that it may pinch | interpose between two main body casings conventionally, the simplification of a structure and size reduction are attained.

  About the electric compressor comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  First, the stator 5a and the rotor 6 of the electric motor 5 are generally constructed by laminating iron-based silicon steel plates, and the main body casing 1 is composed of an aluminum-based alloy for automobiles because of demands such as light weight. Under this premise, the stator 5a made of a material having a coefficient of thermal expansion approximately twice that of the stator 5a is fixed in the circumferential direction via the fixing members 7a and 7b made of a material having a larger thermal expansion coefficient than the stator 5a. Even when the temperature of the main casing 1 is 150 ° C. due to the fastening with the main casing 1, and even when the pressure in the main casing 1 is 10 MPa, the fixing members 7a and 7b are used. It is possible to disperse the internal stress for overcoming the above-described temperature and pressure, for example, securing the shimiro at the time of interference fitting, and the stress burden on the main casing 1 can be reduced.

  In addition to the shrink fitting, there are other cold fittings that cool the stator 5a and so-called interference fitting means that inserts the stator 5a by deforming the main body casing 1 with an external force and releases the external force. Similar effects can be obtained.

(Embodiment 2)
4 (a) and 4 (b) show another example of the fastening means, which is a structure for realizing rotational press-fitting of the stator 5a. In this figure, the inner wall of the main casing 1 is provided with a concave portion 1b having a radius larger than that of the outer peripheral portion except for the D-cut concave portion 7c serving as the gas passage of the fixing members 7a and 7b described above. The diameter of the inner periphery is set smaller than the outer diameter of the fixing members 7a and 7b by the amount of press fit. FIG. 4A shows a state in which the stator 5a having the fixing member 7a (7B) fixed to the main body casing 1 is angularly inserted so as not to contact. 4b shows a state in which the main body casing 1 is rotated about 90 degrees, and the circumferential portion of the fixing member 7a (7B) is rotationally press-fitted into the circumferential portion of the inner wall of the main body casing 1. FIG.

  In this fastening means, as described above, the fixing member 7a (7B) generates little stress due to press fitting, and the main body casing 1 can be expected to relieve stress due to elastic deformation of the fixing member. In addition, it is possible to press-fit with a small rotation angle, and it is not necessary to heat and cool unlike shrink fitting.

  As described above, in the present embodiment, the electric motor and the main body are obtained by using the electric compressor in which the inner peripheral surface of the main body casing 1 and the outer peripheral contact surface of the fixing member 7a (7b) are fixed in the radial direction. When the casing is in a high temperature state, the outer periphery of the fixing member 7a (7b) fixed to the end surface of the electric motor and the inner peripheral contact surface of the main casing 1 are fastened in the radial direction so that the electric motor and the main casing are configured. While suppressing the generation of gaps due to the difference in thermal expansion of the material, it is possible to relieve stress between the main casing and the stator of the motor during fastening, so that the motor and main casing can be fixed without increasing the outer diameter or thickness of the main casing. Fastening can be done.

  Further, the inner circumference of the main body casing and the outer circumference of the fixing member 7a (7b) are circumferential contact surfaces between the adjacent fastening members 8, and the shrinkage fitting of the main body casing 1, the cold fitting of the fixing member, By fixing by any one of the main body casing and the fastening means using elastic deformation by an external force of the fixing member, the stress of the main body casing 1 and the stator 5a of the motor can be relieved at the time of the interference fitting. The electric motor and the main body casing can be fixed and fastened without increasing the diameter and thickness, and the electric compressor can be made small, light, efficient, and highly reliable.

  Moreover, while forming the several recessed part 7c in the outer peripheral part of the fixing member 7a (7b), forming the recessed part 1b of an internal diameter larger than the outer diameter of the said fixing member 7a (7b) in the inner peripheral part of the said main body casing, By fixing the outer peripheral portion of the fixing member 7a (7b) to the inner peripheral portion of the main body casing 1 by rotational press-fitting, it is possible to relieve stress of the stator 5a of the electric motor at the time of press-fitting, which is efficient and reliable. High electric compressor.

(Embodiment 3)
FIG. 5 shows an electric compressor according to a second embodiment of the present invention, and shows a connection relationship between the stator 5 a of the electric motor 5, the fixing member 7 a (7 b), and the main casing 1.

  The fixing member 7 is made of a metal material, and the inner peripheral portion 9 is formed in a shape that protects the winding from hitting the corner of the stator 5a and preventing the film from being damaged when the wire is wound around the stator 5a. . In addition, a non-conductive film 9a is formed on the inner peripheral portion 9 in contact with the winding. In this embodiment, the material of the fixing member 7 is the same as that of the main casing 1 and is a material that can be easily welded. Specifically, it is an alloy mainly composed of aluminum or magnesium. The configuration other than the above is the same as that of the first embodiment.

Next, fixing of the fixing member 7a (7b) will be described with reference to FIG. In FIG. 6, the stator 5 a is installed on the jig 10 and positioned in the main body casing 1. 12 is a schematic diagram showing the beam of the laser welding machine. A welded portion 13 is provided on the outer peripheral contact surface 7d of the main body casing 1 and the fixing member 7a (7b), and the laser beam is focused and irradiated, so Some proximate portions are heated and melted by a beam and welded. The welded portion 13 is set between the two fastening members 8 at the outer peripheral portion of the fixing member 7a (7b).
Also in this embodiment, as described above, the stator 5a generates less stress due to welding, and the body casing 1 can be expected to relieve stress due to elastic deformation of the fixing member 7a (7b). Therefore, the electric motor and the main casing can be fixed and fastened without increasing the outer diameter and wall thickness of the main casing, and the electric compressor can be made compact, lightweight, efficient and highly reliable. it can.

  Further, since the fixing member is made of the same metal material as the main casing, it has excellent weldability, and the same metal material is an alloy mainly composed of aluminum and / or magnesium, so that it is smaller and lighter. It can be made excellent.

  Further, since a non-conductive film is formed in the metal fixing member 7a (7b) where the windings of the motor are close to each other, the winding property to the stator 5a of the motor is excellent and the insulating property is improved. The fixing member 7a (7b) can be provided, and a fixing member having a so-called insulator function can be obtained to have a rational configuration.

  Further, since the fixing member 7a (7b) is formed with a recess 7c serving as a gas passage, the stator 5a of the electric motor is promoted to be cooled by the refrigerant gas, and is an electric compressor having high efficiency and excellent reliability. Can do.

  As described above, the electric compressor according to the present invention is small, light and efficient, and can realize a method of fixing the electric motor to the main body casing with excellent reliability. Therefore, only the electric compressor for an air conditioner of an automobile can be realized. In addition, the present invention can be applied to applications in the field of home appliances such as room air conditioners and water heaters that are required to be small and light.

DESCRIPTION OF SYMBOLS 1 Main body casing 1b Main body casing recessed part 2 Compression part 5 Electric motor 5a Stator 6 Rotor 7, 7a, 7b Fixing member 7c Gas passage (D cut-shaped recessed part)
7d Peripheral contact surface 8 Fastening member 9a Non-conductive film 13 Welded part

Claims (8)

A compressor that performs suction, compression, and discharge of fluid; an electric motor that drives the compressor; and a main body casing that includes the compressor and the motor and is made of a metal material having a larger thermal expansion coefficient than the stator of the motor. And an annular fixing member fixed to an end face of the stator of the electric motor, the fixing member being a material having a larger coefficient of thermal expansion than the stator of the electric motor, and the outer peripheral contact surface of the fixing member being An electric compressor fixed directly to the inner periphery of the main casing by fastening means. The fixing member and the stator of the electric motor are fastened by a plurality of fastening members, and the inner periphery of the main body casing and the outer periphery of the fixing member are circumferential contact surfaces between the adjacent fastening members, and the main body 2. The electric compressor according to claim 1, wherein the electric compressor is fixed by any one of interference fitting using shrink fitting of the casing, cooling fitting of the fixing member, and elastic deformation by an external force of the main body casing or the fixing member. A plurality of concave portions are formed in the outer peripheral portion of the fixing member and the stator of the electric motor, and a concave portion having an outer diameter larger than the outer diameter of the fixing member is formed in the inner peripheral portion of the main body casing. The electric compressor according to claim 1, wherein an outer peripheral portion is fixed to an inner peripheral portion of the main body casing by rotational press-fitting. The fixing member and the stator of the electric motor are fastened by a plurality of fastening members, and the inner periphery of the main body casing and the outer periphery of the fixing member are fixed by welding on a circumferential contact surface between the adjacent fastening members. The electric compressor according to claim 1. The electric compressor according to claim 4, wherein the fixing member is made of the same metal material as the main casing. 6. The electric compressor according to claim 5, wherein the same metal material is aluminum, magnesium, or an alloy mainly composed of both. The electric compressor according to any one of claims 4 to 6, wherein the metal fixing member is provided with a non-conductive coating at a location where the winding of the stator is close. The electric compressor according to claim 1, wherein the fixing member is formed in an annular shape and a gas passage is formed.