Electric compressor

Abstract

The invention provides an electric compressor capable of reducing the size of an end plate for preventing a permanent magnet built in a rotor core of a motor from moving, and realizing reduction of material cost. The electric compressor is provided with a motor (2) having a rotor (23) in which a permanent magnet is embedded in a rotor core (62). The electric compressor is provided with: end plates (71, 72) which are provided at the axial ends of the rotor core (62) and which restrict the axial movement of the permanent magnet (68); and balance weights (73, 74) provided at axial end portions of the rotor core (62). The end plates (71, 72) cover a part of the axial end surface of the rotor core (62), and the balance weights (73, 74) cover the remaining part of the end surface and restrict the axial movement of the permanent magnet (68).

Description

Technical Field

[0001] The present invention relates to an electric compressor including a so-called permanent magnet internal type motor and a compression mechanism driven by the motor to compress a working fluid in a housing. Background Art

[0002] In the past, this type of electric compressor was provided with a motor (electric motor) and a compression mechanism in a housing (sealed shell), and the compression mechanism was driven by the motor to compress the working fluid (refrigerant). In this case, the motor is composed of a stator (fixed element), and a rotor (rotor) that rotates in the stator and has a permanent magnet built into the rotor core. End plates (rotor end plates) are provided at both ends of the rotor in the axial direction to prevent the permanent magnet from moving in the axial direction. In addition, a balancing weight is also provided on the rotor for suppressing vibration during rotation, and the balancing weight is mounted on the surface of the end plate on the opposite side of the rotor core (for example, refer to Patent Document 1).

[0003] Reference Figure 3 , Figure 8 and Fig. 9 The structure of the rotor 100 of the conventional electric compressor will be described. Figure 3 In the figure, 62 is a rotor core having a structure in which a plurality of electromagnetic steel plates are stacked, and a through hole 63 is formed at the center of the rotor core 62, and a rotating shaft (not shown) is installed in the through hole 63. In addition, rivet holes 64 are formed axially through four locations around the through hole 63, and a plurality of weight-reducing holes 66 are formed between adjacent rivet holes 64. The weight-reducing holes 66 are formed in a range that axially penetrates or does not penetrate the rotor core 62, thereby achieving lightweighting of the rotor core 62 and playing a role in achieving balance when the rotor core 62 rotates.

[0004] Slots 67 are formed axially through the periphery of the rotor core 62 at eight locations outside the rivet holes 64 and the lightening holes 66 , and permanent magnets 68 (a plurality of permanent magnets; eight in this example) are respectively inserted into the slots 67 and built into the rotor core 62 .

[0005] exist Figure 8 101 is a conventional end plate. The conventional end plate 101 is annular and is disposed at both axial ends of the rotor core 62. Fig. 9 As shown, the entire end surfaces of the rotor core 62 are covered to restrict the axial movement of the permanent magnets 68. In addition, rivet holes 103 and lightening holes 104 are formed through the end plate 101 at positions corresponding to the rivet holes 64 and lightening holes 66 of the rotor core 62.

[0006] Furthermore, reference numeral 102 is a balancing weight. The balancing weight 102 is provided to suppress vibration when the compression mechanism is driven, and rivet holes (not shown) are formed at two locations on the balancing weight 102. Figure 8 As shown, conventionally, the balance weights 102 are stacked on the surfaces of the end plates 101 at both ends opposite to the rotor core 62, and are fixed to the rotor core 62 together with the end plates 101 by rivets 105 penetrating through the rivet holes 64, 104 ( Figure 8 ).

[0007] Patent Document 1: Japanese Patent No. 5858076

[0008] As described above, in the conventional electric compressor, the end plates 101 cover the entire end surfaces of the rotor core 62 , and the balance weights 102 are stacked on the end plates 101 . This increases the material cost of the end plates 102 . Summary of the invention

[0009] The present invention is proposed to solve the conventional technical problems, and an object of the present invention is to provide an electric compressor capable of reducing the size of an end plate for preventing the movement of a permanent magnet built into a rotor core of a motor, thereby reducing material costs.

[0010] The electric compressor of the present invention comprises in a housing: a motor having a rotor with a permanent magnet built in a rotor core; and a compression mechanism driven by the motor to compress a working fluid, wherein the electric compressor comprises: an end plate arranged at the axial end of the rotor core, for limiting the axial movement of the permanent magnet; and a balancing weight arranged at the axial end of the rotor core, the end plate covering a portion of the axial end face of the rotor core, and the balancing weight covering the remaining portion of the end face, limiting the axial movement of the permanent magnet.

[0011] In the electric compressor according to the second aspect of the invention, in the above invention, the compression mechanism is a scroll compression mechanism in which the movable scroll performs eccentric orbital motion relative to the fixed scroll.

[0012] The electric compressor of the invention of method 3 is based on the invention of method 1, wherein the balance weight has a rivet hole, and the end plate and the rotor core respectively have a rivet hole and a weight reduction hole, the permanent magnet is built into the rotor core at a position further outward than the rivet hole and the weight reduction hole, and the end plate and the balance weight are fixed to the rotor core by rivets passing through the rivet holes.

[0013] The electric compressor of the invention of method 4 is based on the invention of method 1, wherein the end plate and the balance weight are arranged at both axial ends of the rotor core, and the circumferential dimensions of the end plate and the balance weight are different at one end of the rotor core and at the other end.

[0014] In the electric compressor according to the fifth aspect of the invention, in addition to the above-mentioned inventions, a motor is provided between the suction port of the working fluid formed in the casing and the compression mechanism.

[0015] According to the present invention, an electric compressor comprises in a housing: a motor having a rotor with a permanent magnet built in a rotor core; and a compression mechanism driven by the motor to compress a working fluid, the electric compressor comprising: an end plate arranged at the axial end of the rotor core, for limiting the axial movement of the permanent magnet; and a balancing weight arranged at the axial end of the rotor core, the end plate covering a portion of the axial end face of the rotor core, and the balancing weight covering the remaining portion of the end face, limiting the axial movement of the permanent magnet, thereby being able to reduce the size of the end plate used to prevent the permanent magnet built in the rotor core from moving, and to achieve a reduction in material costs.

[0016] That is, for example, through the invention of method 2, in a so-called scroll-type electric compressor having a scroll compression mechanism in which a movable scroll plate performs eccentric orbital motion, the axial movement of the permanent magnet is directly limited by the balancing weight required to suppress vibration, thereby achieving a reduction in the size of the end plate. This is extremely effective in reducing the cost of the electric compressors of the inventions of methods 2 and 5.

[0017] In this case, as in the invention of method 3, where the balance weight has a rivet hole and the end plate and the rotor core respectively have a rivet hole and a lightening hole, if the permanent magnet is built into the rotor core at a position further outward than the rivet hole and the lightening hole, and the end plate and the balance weight are fixed to the rotor core by rivets passing through the rivet holes, the permanent magnet will not interfere with the rivet and the lightening hole.

[0018] In addition, by arranging the end plates and the balance weights at both axial ends of the rotor core as in the invention of method 4, and setting the circumferential dimensions of the end plates and the balance weights to be different at one end of the rotor core and at the other end, the freedom of the rotor balance adjustment can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a longitudinal sectional side view of the electric compressor to which one embodiment of the present invention is applied. Figure 2 It is composed Figure 1 A three-dimensional view of a rotor of a motor of an electric compressor (viewed from the front bearing side). Figure 3 yes Figure 2 A three-dimensional view of the rotor core of a rotor. Figure 4 is Figure 3 A three-dimensional diagram showing the rotor core with end plates and balance weights (seen from the front bearing side). Figure 5 is Figure 3 A three-dimensional diagram showing the rotor core with end plates and balance weights (seen from the rear bearing side). Figure 6 It's fixed with rivets. Figure 4 Diagram showing the state of the rotor core, end plates and balance weights. Figure 7 It's fixed with rivets. Figure 5 Diagram showing the state of the rotor core, end plates and balance weights. Figure 8 It is a perspective view of a rotor constituting a motor of a conventional electric compressor. Fig. 9 yes Figure 8 A three-dimensional view of the rotor core and end plates of a rotor. DETAILED DESCRIPTION

[0020] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Figure 1 It is a longitudinal sectional side view of the electric compressor 1 according to one embodiment of the present invention.

[0021] The electric compressor 1 of the embodiment is a so-called horizontally mounted inverter-integrated scroll electric compressor, which is used, for example, in the refrigerant circuit of an air-conditioning device for an electric vehicle, and sucks in a refrigerant as a working fluid of the air-conditioning device, compresses the refrigerant and discharges it to a discharge pipe. The electric compressor 1 includes a three-phase motor 2 as an embodiment of the motor in the present invention, an inverter 3 for operating the motor 2, and a scroll compression mechanism 4 as an embodiment of a compression mechanism driven by the motor 2.

[0022] The electric compressor 1 of the embodiment comprises: a stator housing 7, which accommodates a motor 2 and a center housing 6 on the inside; an inverter box 8, which is installed on an end wall 7A on one end side of the stator housing 7 and accommodates an inverter 3 on the inside; and a rear housing 9, which is installed on the other end side of the stator housing 7.

[0023] The stator housing 7 , the inverter case 8 , and the rear housing 9 are all made of metal (aluminum in the embodiment), and are integrally joined to form a housing 11 of the electric compressor 1 of the embodiment.

[0024] A motor chamber 12 for accommodating the motor 2 is formed in the stator housing 7, and one end face of the motor chamber 12 is basically closed by the end wall 7A of the stator housing 7. The end wall 7A is a partition wall that divides the motor chamber 12 from the inverter accommodating portion 13 described later. The other end face of the motor chamber 12 is open, and after the motor 2 is accommodated in the opening, the center housing 6 is accommodated. In addition, a front bearing 16 for rotatably supporting one end of the rotating shaft 14 of the motor 2 is installed on the inner surface (motor chamber 12 side) of the end wall 7A.

[0025] The center housing 6 has an opening on the side opposite to the motor 2 (the other end side). After the movable scroll 22 of the scroll compression mechanism 4, which will be described later, is accommodated in the opening, the opening is closed by fixing the rear housing 9 to the stator housing 7. The rear housing 9 is fixed with a fixed scroll 21, which will be described later, of the scroll compression mechanism 4.

[0026] In addition, a through hole 17 is opened in the center housing 6 for the other end of the rotating shaft 14 of the motor 2 to pass through, and a rear bearing 18 is installed on the side of the scroll compression mechanism 4 of the through hole 17 and in the center housing 6. The rear bearing 18 supports the other end of the rotating shaft 14 on the side of the scroll compression mechanism 4 so that it can rotate.

[0027] The motor 2 is composed of a stator 25 on which a coil is wound and fixed to the inner side of the peripheral wall of the stator housing 7, and a rotor 23 that rotates inside the stator 25. The rotor 23 will be described in detail later. For example, the inverter 3 converts a direct current from a battery (not shown) of the vehicle into a three-phase alternating current, and supplies power to the coil of the stator 25 of the motor 2, thereby driving the rotor 23 to rotate. The rotating shaft 14 is fixed to the rotor 23.

[0028] In addition, the stator housing 7 is formed with a suction port 20, and the refrigerant sucked from the suction port 20 flows into the center housing 6 after passing through the motor 2 in the stator housing 7, and is sucked into the suction portion 37 outside the scroll compression mechanism 4. That is, since the motor 2 is provided between the suction port 20 and the scroll compression mechanism 4, the motor 2 is cooled by the sucked refrigerant. In addition, the refrigerant compressed by the scroll compression mechanism 4 is configured to be ejected from the ejection chamber 27 described later via the ejection port 30 formed in the rear housing 9 to the ejection piping of the refrigerant circuit (not shown) outside the housing 11.

[0029] The scroll compression mechanism 4 is composed of the aforementioned fixed scroll 21 and movable scroll 22. The fixed scroll 21 is integrally provided with a disc-shaped cover plate 23 and a spiral volute (wrap) 24 which is upright on the surface (one surface) of the cover plate 23 and is formed of an involute shape or a curve similar to the involute shape, and the surface of the cover plate 23 on which the volute 24 is upright is fixed to the rear housing 9 as the center housing 6 side. A discharge hole 26 is formed in the center of the cover plate 23 of the fixed scroll 21, and the discharge hole 26 is connected to the discharge chamber 27 in the rear housing 9. In the figure, 28 is a discharge valve, and the discharge valve 28 is provided at an opening of the discharge hole 26 located on the back side (the other surface) of the cover plate 23.

[0030] The movable scroll 22 is a scroll that performs eccentric orbital motion (orbital motion) relative to the fixed scroll 21, and is integrally provided with a disc-shaped cover plate 31, a spiral volute 32 in an involute shape or a spiral volute formed by a curve similar to the involute shape and arranged upright on the surface (one surface) of the cover plate 31, and a boss 33 protrudingly formed at the center of the back surface (the other surface) of the cover plate 31. The movable scroll 22 is arranged in such a manner that the volute 32 and the volute 24 of the fixed scroll 21 are opposed and meshed with each other with the protruding direction of the volute 32 being the fixed scroll 21 side, and a pressure chamber 34 is formed between each volute 24, 32.

[0031] That is, the volute 32 of the movable scroll 22 is opposed to the volute 24 of the fixed scroll 21, and meshes with each other in a manner that the top end of the volute 32 contacts the surface of the cover plate 23 and the top end of the volute 24 contacts the surface of the cover plate 31, and the eccentric portion 36 eccentrically provided from the axis at the other end of the rotating shaft 14 is engaged with the boss 33 of the movable scroll 22. Furthermore, if the rotating shaft 14 rotates together with the rotor 23 of the motor 2, the movable scroll 22 does not rotate but performs an eccentric orbital motion (orbital motion) relative to the fixed scroll 21.

[0032] Since the movable scroll 22 revolves eccentrically relative to the fixed scroll 21, the eccentric directions and contact positions of the volutes 24 and 32 move while rotating, and the pressure chamber 34 after sucking the refrigerant from the suction portion 37 on the outside gradually shrinks while moving inward. As a result, the refrigerant is compressed and finally ejected from the central ejection hole 26 via the ejection valve 28 to the ejection chamber 27.

[0033] exist Figure 1 , 38 is an annular thrust plate. The thrust plate 38 is used to divide the back pressure chamber 39 and the suction portion 37 on the outside of the scroll compression mechanism 4, and is located outside the boss 33, and is sandwiched between the center housing 6 and the movable scroll 22. The back pressure chamber 39 is formed between the back side of the cover plate 31 of the movable scroll 22 and the center housing 6. In addition, 41 is a sealing material installed on the back side of the cover plate 31 of the movable scroll 22 and abutting against the thrust plate 38, and the back pressure chamber 39 and the suction portion 37 are divided by the sealing material 41 and the thrust plate 38.

[0034] In addition, reference numeral 48 denotes a centrifugal oil separator installed in the discharge chamber 27 of the rear housing 9 (housing 11). The oil separator 48 separates the lubricating oil mixed in the refrigerant discharged from the scroll compression mechanism 4 to the discharge chamber 27 from the refrigerant. An inlet 49 is formed in the oil separator 48, and the refrigerant containing oil flowing in from the inlet 49 rotates in the oil separator 48. The oil is separated by the centrifugal force at this time, and the refrigerant is discharged from the outflow port at the upper end toward the discharge port 30 and discharged to the discharge pipe as described above.

[0035] An oil storage chamber 44 is formed in the rear housing 9 below the oil separator 48, and the oil separated from the refrigerant by the oil separator 48 flows into the oil storage chamber 44 from the lower end of the oil separator 48. In the figure, 43 is a back pressure passage formed from the rear housing 9 to the center housing 6. The back pressure passage 43 is a path that connects the oil separator 48 in the discharge chamber 27 (discharge side of the scroll compression mechanism 4) in the rear housing 9 with the back pressure chamber 39, and has a throttle hole 50 in the embodiment. Thus, it is configured to supply the discharge pressure adjusted by the throttle hole 50 of the back pressure passage 43 to the back pressure chamber 39 together with the oil in the oil storage chamber 44 separated by the oil separator 48.

[0036] The pressure (back pressure) in the back pressure chamber 39 generates a back pressure load that presses the movable scroll 22 against the fixed scroll 21. The back pressure load overcomes the compression reaction force from the pressure chamber 34 of the scroll compression mechanism 4, presses the movable scroll 22 against the fixed scroll 21, maintains the contact between the volutes 24, 32 and the cover plates 31, 23, and compresses the refrigerant in the pressure chamber 34.

[0037] On the other hand, the inverter box 8 is composed of a box body 10 and a cover member 15 that closes an opening of one end surface of the box body 10. The box body 10 constitutes an inverter accommodating portion 13 that accommodates the inverter 3. After the inverter 3 is accommodated in the inverter accommodating portion 13, the cover member 15 is mounted on the box body 10. The inverter 3 of the embodiment is configured such that a control circuit is mounted on a circuit substrate 51 and a switching element, a smoothing capacitor, etc. that are not shown in the figure are connected.

[0038] Here, a sealing plate 52 is mounted on the end wall 7A (partition wall) of the stator housing 7, and a conductive sealing pin 53 is mounted on the sealing plate 52. In this case, three sealing pins 53 are mounted corresponding to each phase (three phases) of the motor 2, and one end side of each sealing pin 53 penetrates the end wall 7A and enters the motor chamber 12, and is connected to the coil of the stator 25 of the motor 2.

[0039] In addition, three metal press-fit terminals 56 called power baskets are mounted on the circuit substrate 51 at positions corresponding to the other ends of the sealing pins 53. The other ends of the sealing pins 53 enter the press-fit terminals 56 and are pressed (press-fitted) against the press-fit terminals 56. Thus, the sealing pins 53 are electrically connected to the circuit substrate 51.

[0040] Next, refer to Figure 2~Figure 7 The structure of the aforementioned rotor 23 of the motor 2 is described in detail. The rotor 23 of the embodiment is also configured by integrating the rotor core 62, the end plates 71, 72, and the balance weights 73, 74 by rivets 76. Figure 3That is, the rotor core 62 is formed by stacking a plurality of electromagnetic steel plates, and a through hole 63 is formed at the center of the rotor core 62, and the rotating shaft 14 is mounted in the through hole 63.

[0041] In addition, rivet holes 64 are formed at four locations around the through hole 63 in the axial direction, and a plurality of lightening holes 66 are formed between adjacent rivet holes 64. The lightening holes 66 are formed in a range that axially penetrates or does not penetrate the rotor core 62, thereby reducing the weight of the rotor core 62 and achieving balance when the rotor core 62 rotates.

[0042] Slots 67 are formed axially through the periphery of the rotor core 62 at eight locations outside the rivet holes 64 and the lightening holes 66 , and permanent magnets 68 (a plurality of permanent magnets, eight in the embodiment) are respectively inserted into the slots 67 and built into the rotor core 62 .

[0043] exist Figure 1 , Figure 2 , Figure 4~Figure 7 In the embodiment, the end plates 71 and 72 are approximately semicircular (approximately half the shape of a circular ring), and the end plate 71 is provided at one end of the rotor core 62 in the axial direction (the end on the front bearing 16 side). Figure 4 , Figure 6 As shown, the end plate 71 covers approximately half (a portion of the end surface) of one end surface of the rotor core 62 to restrict the axial movement of the permanent magnet 68. Rivet holes 77 and lightening holes 78 are also formed through the end plate 71 at positions corresponding to the rivet holes 64 and lightening holes 66 of the rotor core 62.

[0044] In addition, the end plate 72 is provided at the other end portion (the end portion on the rear bearing 18 side) of the rotor core 62 in the axial direction. Figure 5 , Figure 7 As shown, the end plate 72 covers approximately half (a portion of the end surface) of the other end surface of the rotor core 62, restricting the axial movement of the permanent magnet 68. In addition, the end plate 72 is provided at a position on the opposite side of the end plate 71 across the through hole 63, corresponding to the end plate 71. The end plate 72 also has a rivet hole 79 and a lightening hole 81 formed through the position corresponding to the rivet hole 64 and the lightening hole 66 of the rotor core 62.

[0045] Furthermore, the balancing weights 73 and 74 of the embodiment are also provided to suppress the vibration when the scroll compression mechanism 4 is driven, and the balancing weight 73 is substantially in the shape of a semicircular arc (a shape substantially half of a circular ring). The balancing weight 73 is provided at one end portion of the rotor core 62 in the axial direction (the end portion on the front bearing 16 side). Figure 4 , Figure 6As shown, the balance weight 73 covers approximately half of the end surface of one side of the rotor core 62 (the remaining part of the end surface) that is not covered by the end plate 71, thereby restricting the axial movement of the permanent magnet 68. A rivet hole 82 is also formed through the balance weight 73 at a position corresponding to the rivet hole 64 of the rotor core 62.

[0046] The balance weight 74 is also in a substantially semicircular arc shape (a shape that is substantially half of a circular ring shape). The balance weight 74 is disposed at the other axial end of the rotor core 62 (the end on the rear bearing 18 side). Figure 5 , Figure 7 As shown, the end plate 72 covers approximately half of the other end surface of the rotor core 62 (the remaining part of the end surface) that is not covered by the end plate 72, thereby restricting the axial movement of the permanent magnet 68. In addition, the balance weight 74 is also provided at a position opposite to the balance weight 73 across the through hole 63, corresponding to the balance weight 73. A rivet hole 83 is also formed through the balance weight 74 at a position corresponding to the rivet hole 64 of the rotor core 62.

[0047] Furthermore, the end plates 71, 72 and the balance weights 73, 74 are fixed to the rotor core 62 ( Figure 1 , Figure 2 , Figure 6 , Figure 7 ).

[0048] Thus, in the present invention, since the end plates 71, 72 cover a portion of the axial end face of the rotor core 62 (approximately half in the embodiment), and the balance weights 73, 74 cover the remaining portion of the end face, the axial movement of the permanent magnet 68 is restricted. Therefore, the size of the end plates 71, 72 used to prevent the movement of the permanent magnet 68 built into the rotor core 62 can be reduced compared to the past (reduced to approximately half in the embodiment), and the material cost of the end plates 71, 72 can be reduced.

[0049] That is, by directly limiting the axial movement of the permanent magnet 68 by the balancing weights 73 and 74 required to suppress vibration in the electric compressor 1 having the scroll compression mechanism 4 that performs eccentric orbital motion of the movable scroll plate 22 as in the embodiment, the size of the end plates 71 and 72 can be reduced, which is extremely effective in achieving cost reduction of the electric compressor 1.

[0050] In this case, in the embodiment, the balancing weights 73, 74 have rivet holes 82, 83, and the end plates 71, 72 and the rotor core 62 have rivet holes 77, 79, 64 and lightening holes 78, 81, 66, respectively. The permanent magnet 68 is built into the rotor core 62 at a position closer to the outside than these rivet holes and the lightening holes. The end plates 71, 72 and the balancing weights 73, 74 are fixed to the rotor core 62 by rivets 76 that pass through the rivet holes 82, 83, 77, 79, 64, so that the permanent magnet 68 does not interfere with the rivets 82, 83, 77, 79, 64 and the lightening holes 78, 81, 66.

[0051] The circumferential dimensions of the end plate 71 and the balance weight 73 provided at one end of the rotor core 62 and the circumferential dimensions of the end plate 72 and the balance weight 74 provided at the other end may be the same, but may be different. Figure 4 and Figure 5 It is understood that in the above-mentioned embodiment, the circumferential dimension of the balance weight 74 is also set to be slightly larger than the circumferential dimension of the balance weight 73. This can improve the degree of freedom in the balance adjustment of the rotor 23.

[0052] In addition, the specific shapes of the end plates 71 and 72 and the balance weights 73 and 74 shown in the embodiment are not limited thereto, and can obviously be changed within the scope not departing from the gist of the present invention. Description of Reference Numerals

[0053] 1 Electric compressor 2 Motor 4 Scroll compression mechanism (compression mechanism) 7 Stator housing 11. Housing 12 Motor room 20 suction port 23 Rotor 62 rotor core 68 permanent magnets 64, 77, 79, 82, 83 Rivet holes 66, 78, 81 weight reduction holes 71, 72 end plate 73, 74 Balance weight 76 Rivets.

Claims

1. An electric compressor comprising: a motor having a rotor with a permanent magnet built into a rotor core; and a compression mechanism driven by the motor to compress a working fluid, The electric compressor is characterized by comprising: an end plate, disposed at an axial end of the rotor core, for limiting the axial movement of the permanent magnet; and A balancing weight is arranged at the axial end of the rotor core. The end plate covers a portion of the axial end surface of the rotor core, and The balancing weight covers the remaining portion of the end surface to limit the axial movement of the permanent magnet.

2. The electric compressor according to claim 1, characterized in that: The compression mechanism is a scroll compression mechanism in which a movable scroll performs an eccentric orbital motion relative to a fixed scroll.

3. The electric compressor according to claim 1, characterized in that: The balancing weight has a rivet hole, and The end plate and the rotor core have rivet holes and weight-reducing holes respectively. The permanent magnet is built into the rotor core at a position further outside than the rivet hole and the lightening hole. The end plates and the balance weights are fixed to the rotor core by rivets penetrating through the rivet holes.

4. The electric compressor according to claim 1, characterized in that: The end plates and the balance weights are disposed at both axial ends of the rotor core, and The circumferential dimensions of the end plate and the balance weight are different at one end of the rotor core and at the other end.

5. The electric compressor according to any one of claims 1 to 4, characterized in that: The motor is provided between the suction port of the working fluid formed in the casing and the compression mechanism.

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