Electric compressor

Abstract

An electric compressor comprises a housing (1), a rotating shaft (5) rotatably supported in the housing (1), a motor (7) that rotates the rotating shaft (5), and a compression element (10) that compresses a fluid. The housing (1) has a projection (4, 40) extending towards the motor (7), and the projection (4, 40) has an inner circumferential surface (42, 48) in which a bearing (19) supporting the rotating shaft (5) is provided. The projection (4, 40) has an asymmetrical shape and an outer circumferential surface (41) that varies in distance from the inner circumferential surface (42, 48) in a radial direction of the rotating shaft (5). The rotating shaft (5) is pressed into the bearing (19) and the bearing (19) is fitted into the inner circumferential surface (42, 48) with a clearance between the bearing (19) and the inner circumferential surface (42, 48).

Description

STATE OF THE ART

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

[0002] Japanese patent application No. 2012-057504 (JP 2012-057504A) discloses a conventional electric compressor. This electric compressor comprises a housing, a rotating shaft rotatably supported within the housing, a motor configured to rotate the shaft, and a compression element configured to compress a fluid by the rotation of the shaft. The housing has a tube-shaped extension projecting towards the motor. A bearing supporting the rotating shaft is provided on an inner circumferential surface of the extension.

[0003] The bearing is, in particular, a ball bearing comprising an inner ring, an outer ring, and a plurality of ball bearing balls positioned between the inner and outer rings. In this design of an electric compressor, the rotating shaft is generally fitted into the inner ring of the bearing with a clearance between the rotating shaft and the inner ring, and the outer ring of the bearing is generally pressed into the inner circumferential surface of the shoulder, although details of this aspect are not clearly disclosed in the patent application.

[0004] In recent years, there has been a requirement to further miniaturize electric compressors. This requirement necessitates a reduction in the housing diameter. However, due to the reduced housing diameter, ensuring sufficient space for the extension within the housing becomes challenging. Therefore, the extension may be shaped to avoid interference with other components within the motor chamber, or conversely, it may be integrated with part of the other component. This complicates the extension's shape, resulting in an asymmetrical form with an outer circumferential surface that varies in distance from the inner circumferential surface along the radial direction of the rotating shaft. In short, the extension's wall thickness is not uniform; that is, it has both thick and thin wall sections.

[0005] Here, when a bearing is pressed into such a boss with varying wall thicknesses, slight deformations of the boss occur during the pressing process, causing it to become slightly stressed or distorted. This stress or distortion then also slightly stresses or distorts the bearing held by the boss.

[0006] As a result, the bearing's lifespan decreases. Furthermore, due to bearing tension, the bearing does not adequately support the rotating shaft, leading to potential shaft runout. This can cause the electric compressor to become noisier.

[0007] The present invention has been made in view of the conventional circumstances described above and is aimed at providing an electric compressor which has a high durability and low noise level, while the electric compressor is miniaturized. SUMMARY

[0008] According to one aspect of the present invention, an electric compressor is provided comprising a housing, a rotating shaft rotatably supported in the housing, a motor configured to rotate the rotating shaft, and a compression element configured to compress a fluid by the rotation of the rotating shaft. The housing has a projection formed in a tubular shape extending axially from the rotating shaft to the motor, and the projection has an inner circumferential surface in which a bearing supporting the rotating shaft is provided. The projection has an asymmetrical shape and an outer circumferential surface that varies in distance from the inner circumferential surface in a radial direction of the rotating shaft. The rotating shaft is pressed into the bearing, and the bearing is fitted with a clearance between the bearing and the inner circumferential surface.

[0009] Other aspects and advantages of the invention will become apparent from the following description, which is taken together with the accompanying drawings, which exemplify the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The invention, along with its tasks and advantages, can best be understood by referring to the following description of the embodiments together with the accompanying drawings, in which: Fig. 1 a sectional view according to an electric compressor of a first embodiment; Fig. 2 a sectional view along a line AA in Fig. 1 is taken, according to the electric compressor of the first embodiment; Fig. 3 a sectional view along a line BB in Fig. 2 is taken, which represents a state in which a rotating shaft is supported by a bearing which is received at a projection, while the bearing is held by the projection, according to the electric compressor of the first embodiment; Fig. 4 an enlarged view of a main part of Fig. 2, which represents the approach according to the electric compressor of the first embodiment; Fig. 5 a schematic sectional view, drawn along a line CC in Fig. 3 is taken, according to the electric compressor of the first embodiment; Fig. 6 a sectional view, similar to Fig. 2 is, which represents a state in which an inverter is connected to a motor by a group block, according to the electric compressor of the first embodiment; and Fig. 7 a sectional view, similar to Fig. 3 is a state in which a rotating shaft is supported by a bearing which is received at a projection, while the bearing is held by the projection, according to an electric compressor of a second embodiment. DETAILED DESCRIPTION OF THE EXECUTION FORMS

[0011] A first and a second embodiment of the present invention are described below with reference to the drawings. In particular, the electric compressors of the first and second embodiments (hereinafter referred to simply as compressors) are electric compressors of a scroll or spiral design, respectively. These compressors are each mounted in a vehicle, which is not shown, and serve as part of a refrigeration circuit of the vehicle. (First embodiment)

[0012] As in Fig. As shown in Figure 1, the compressor of the first embodiment has a housing 1, an inverter 3, a rotating shaft 5, a motor 7 and a compression part 10.

[0013] In the present embodiment, a forward-reverse direction of the compressor is defined by a double-headed solid arrow, which is in Fig. 1 is shown. Fig. 3 and the following drawings show the forward-reverse direction of the compressor in accordance with Fig. 1 defined. It should be noted that this forward-reverse direction is an example for the sake of clarity and the position of the compressor, where appropriate, will be changed in accordance with a vehicle in which the compressor is mounted, or similar.

[0014] As in Fig. As shown in Figure 1, the housing 1 comprises a motor housing 13, a compressor housing 14, a stationary block 15, and an inverter cover 2. The motor housing 13, the compressor housing 14, the stationary block 15, and the inverter cover 2 are all made of an aluminum alloy. The inverter cover 2 corresponds to a front section of the housing 1, and the compressor housing 14 corresponds to a rear section of the housing 1.

[0015] The motor housing 13 has a first front wall 13a and a first circumferential wall 13b. The first front wall 13a is an example of the "partition" in the present invention. The first front wall 13a is located at a front end of the motor housing 13 and extends radially along the rotating shaft 5 and radially along the motor housing 13. The first circumferential wall 13b is connected to the first front wall 13a and extends rearward from the first front wall 13a in a direction in which an axis of rotation O extends. The direction in which the axis of rotation O extends is parallel to the forward-reverse direction of the compressor.

[0016] The motor housing 13, which has the first front wall 13a and the first circumferential wall 13b, is designed in a tubular shape with a bottom, which is open at a rear end of the motor housing 13. The first front wall 13a and the first circumferential wall 13b form a motor chamber 17 within the motor housing 13.

[0017] The first front wall 13a has a front surface 131 and a rear surface 132. The front surface 131 is oriented towards the front of the motor housing 13. The rear surface is located opposite the front surface 131 across the first front wall 13a and is oriented towards the motor chamber 17.

[0018] Furthermore, as in Fig. Figure 2 shows a first projection 4, a projecting section 6, and a through-hole 8 formed in the first front wall 13a. The first projection 4 is an example of the "projection" in the present invention. It should be noted that illustrations of the rotary shaft 5, the motor 7, and the first radial ball bearing 19, which is described later, are shown in Figure 2. Fig. 2. These have been omitted for the sake of clarity. The same applies to Fig. 6.

[0019] As in Fig. As shown in Figure 2, the first approach 4 is formed in one piece with the first front wall 13a. As in Fig. 1 and Fig. As shown in Figure 3, the first projection 4 extends from the rear surface 132 in the direction in which the axis of rotation O extends towards the motor 7. That is, the first projection 4 extends backward from the rear surface 132 into the motor chamber 17. The first projection 4 is essentially cylindrical in shape and extends around the axis of rotation O. A first radial ball bearing 19 is held by the first projection 4. The first radial ball bearing 19 is an example of the "bearing" in the present invention. These configurations of the first projection 4 and the first radial ball bearing 9 will be described in detail later.

[0020] As in Fig. As shown in Figure 2, the projecting section 6 is located outside and near the first projection 4. The projecting section 6 extends from the rear surface 132 into the motor chamber 17. At one of its rear ends, the projecting section 6 has a rear end surface 6a. Part of the rear end surface 6a is flat. The through-hole 8 is an elongated hole that extends through the first front wall 13a in the direction of the axis of rotation O and is arranged to overlap the projecting section 6. That is, the through-hole 8 extends from the front surface 131 of the first front wall 13a to the rear end surface 6a of the projecting section 6. Thus, an outer surface of the motor housing 13 is connected to the motor chamber 17 via the through-hole 8.

[0021] As in Fig. As shown in Figure 1, the first circumferential wall 13b of the motor housing 13 has a suction opening 13c. The suction opening 13c extends radially through the first circumferential wall 13b of the motor housing 13, and an evaporator is connected to the motor chamber 17 via a pipe and the suction opening 13c. Illustrations of the evaporator and the pipe are omitted here. A refrigerant gas flowing through the evaporator is drawn into the motor chamber 17 through the pipe and the suction opening 13c. The refrigerant gas is an example of the "fluid" in the present invention.

[0022] Furthermore, as in Fig. As shown in Figure 2, six first screw holes 13d are formed in a rear section of the first circumferential wall 13b, and two positioning pins 13e are fixed to the rear section of the first circumferential wall 13b. The first screw holes 13d extend forward from a rear end face 133 of the first circumferential wall 13b (see Figure 2). Fig. 1) The positioning pins 13e, which are in Fig. 2 shown are fixed to the first circumferential wall 13b by a section of each of the positioning pins 13e, which projects backwards from the rear end surface 133.

[0023] As in Fig. As shown in Figure 1, the compressor housing 14 has a rear wall 14a and a second circumferential wall 14b. The rear wall 14a is located at a rear end of the compressor housing 14 and extends radially along the housing. The second circumferential wall 14b is connected to the rear wall 14a and extends forward from the rear wall 14a. The compressor housing 14, comprising the rear wall 14a and the second circumferential wall 14b, is formed in a tubular shape with a bottom that is open at a front end.

[0024] An oil separator chamber 14c, a first discharge recess 14d, a discharge passage 14e, a discharge opening 14f, and six secondary screw holes 14g are formed in the compressor housing 14. The oil separator chamber 14c is located at a rear section of the compressor housing 14 and extends radially along the compressor housing 14. The first discharge recess 14d is located in front of the oil separator chamber 14c in the compressor housing 14 and is recessed into the oil separator chamber 14c. The discharge passage 14e extends in the forward-reverse direction of the compressor, and the oil separator chamber 14c is connected to the first discharge recess 14d via the discharge passage 14e. The discharge port 14f is open to an outer surface of the compressor housing 14, and the outer surface of the compressor housing 14 is connected to the oil separator chamber 14c via the discharge port 14f. The discharge port 14f is connected to a capacitor by a line.Here, representations of the capacitor and the line have been omitted. The second screw holes 14g are formed in the second circumferential wall 14b and extend through the second circumferential wall 14b in the forward-backward direction of the compressor. It should be noted that one of the six second screw holes 14g is located in... Fig. 1 is shown.

[0025] An oil separator cylinder 21 is fixed in the oil separator chamber 14c. The separator consists of an inner circumferential surface of the oil separator chamber 14c and an outer circumferential surface of the oil separator cylinder 21. Furthermore, a filter 23 is provided below the oil separator cylinder 21 in the oil separator chamber 14c.

[0026] The stationary block 15 is provided between the motor housing 13 and the compressor housing 14. The stationary block 15 has a second projection 15a that extends forward. An insertion hole 15b is formed at one end of the second projection 15a. A second radial ball bearing 27 and a sealing element 29 are provided at the second projection 15a. Furthermore, six third-hand screw holes 15c are formed in the stationary block 15. The third-hand screw holes 15c are located outside the second projection 15a and extend through the stationary block 15 in the forward-reverse direction of the compressor. Although not shown, the stationary block 15 has positioning recesses corresponding to the positioning pins 13e of the motor housing 13. It should be noted that one of the six third-hand screw holes 15c is located in Fig. 1 is shown.

[0027] The first screw holes 13d of the motor housing 13, the second screw holes 14g of the compressor housing 14, and the third screw holes 15c of the stationary block 15 are each aligned in the forward-reverse direction of the compressor. Furthermore, the positioning pins 13e of the motor housing 13 are inserted into the positioning recesses of the stationary block 15. The motor housing 13, the compressor housing 14, and the stationary block 15 are thus positioned relative to one another. The motor housing 13, the compressor housing 14, and the stationary block 15 are fixed to one another by six screws 25, which are inserted from one side of the compressor housing 14 through the second screw holes 14g, the third screw holes 15c, and the first screw holes 13d in that order. Thus, the motor housing 13, the compressor housing 14, and the stationary block 15 are integrated together.It should be noted that a method for fixing the motor housing 13, the compressor housing 14, and the stationary block 15 to one another may be appropriately designed. Furthermore, the number of first screw holes 13d, the number of second screw holes 14g, and the number of third screw holes 15c may, if appropriate, be designed in accordance with the number of screws 25.

[0028] If the motor housing 13, the compressor housing 14 and the stationary block 15 are fixed to one another in such a manner as shown in Fig. As shown in Figure 1, the stationary block 15 is located in the forward-reverse direction of the compressor between the motor chamber 17 and the compression part 10. Here, the second extension 15a projects forward towards the motor chamber 17.

[0029] The stationary block 15 not only has a plurality of suction passages 55, but also a plurality of anti-rotation pins 31 are fixed to the stationary block 15. The suction passages 55 are located outside the second projection 15a and inside the third screw holes 15c and extend through the stationary block 15 in the forward-reverse direction of the compressor. Thus, the motor chamber 17 is connected to an inner side of the compressor housing 14 via the suction passages 55. The anti-rotation pins 31 are fixed to the stationary block 15 while projecting backward into the stationary block 15. It should be noted that one of the suction passages 55 and one of the anti-rotation pins 31 in Fig. 1 are shown.

[0030] The inverter cover 2 is located in front of the motor housing 13. The inverter cover 2 has a second front wall 2a and a third circumferential wall 2b. The second front wall 2a is located at a front end of the inverter cover 2 and extends radially along the cover. The third circumferential wall 2b is connected to the second front wall 2a and extends rearward from the second front wall 2a. The inverter cover 2, comprising the second front wall 2a and the third circumferential wall 2b, is formed in a tubular shape with a base that is open at a rear end. It should be noted that the inverter cover 2 may be made of a resin.

[0031] A rear end of the third circumferential wall 2b of the inverter cover 2 is in contact with the front surface 131 of the first front wall 13a of the motor housing 13. In this state, the inverter cover 2 is fixed to the motor housing 13 by a plurality of screws, which are not shown. Thus, the inverter cover 2, the motor housing 13, the stationary block 15, and the compressor housing 14 are fixed in this order, forming the housing 1. The inverter cover 2 interacts with the first front wall 13a to form an inverter chamber 18 between them. That is, the motor chamber 17 is separated from the inverter chamber 18 by the first front wall 13a. The inverter chamber 18 communicates with the through-hole 8, as shown in Fig. 2 is shown. Although not shown, a connector section is formed in the second front wall 2a of the inverter cover 2.

[0032] Inverter 3 is, as in Fig. The inverter 3, shown in Figure 1, is housed in inverter chamber 18. Inverter 3 comprises a circuit board 3a, a switching element 3b, and hermetically sealed terminals 3c, which are located in Fig. 2 are shown, and similar details. The circuit board 3a is fixed to the front surface 131 of the first front wall 13a of the motor housing 13 by screws, which are not shown. The circuit board 3a is connected to a battery provided in the vehicle via the connector section. The battery is not shown in the illustration. The switching element 3b is provided on the circuit board 3a. Since the circuit board 3a is fixed to the front surface 131, the switching element 3b faces the front surface 131 and comes into contact with it. This contact dissipates heat generated by the switching element 3b during compressor operation to the first front wall 13a. It should be noted that the switching element 3b can be positioned away from the first front wall 13a.

[0033] The hermetically sealed terminals 3c, which are in Fig. The terminals shown in Figure 2 are connected to the circuit board 3a. Furthermore, the hermetically sealed terminals 3c are located in the through-hole 8 and fixed to the first front wall 13a of the motor housing 13 by screws (not shown). Thus, the hermetically sealed terminals 13c in the through-hole 8 face the motor chamber 17, while the hermetically sealed terminals 3c are inserted in the through-hole 18. The hermetically sealed terminals 3c provide a seal between the inverter chamber 18 and the motor chamber 17. It should be noted that the shape of each of the hermetically sealed terminals 3c may be appropriately designed. The shape of the through-hole 8 may also, if appropriate, be designed to correspond to the shapes of the hermetically sealed terminals 3c.

[0034] As in Fig. As shown in Figure 1, the rotating shaft 5 is provided in the housing 1. The rotating shaft 5 is made of steel and is formed in a column shape that extends in the forward-reverse direction of the compressor. The rotating shaft 5 has a small-diameter section 5a, a large-diameter section 5b, and a tapered section 5c. Although the detailed description is omitted, the rotating shaft 5 is formed by machining. Thus, the small-diameter section 5a, the large-diameter section 5b, and the tapered section 5c each have a cross-section of an essentially perfect circle, which is perpendicular to the rotating shaft 5. The rotating shaft 5 also has an outer circumferential surface 501. The outer circumferential surface 501 is formed by an outer circumferential surface of the small-diameter section 5a, an outer circumferential surface of the large-diameter section 5b and an outer circumferential surface of the tapered section 5c.

[0035] The small-diameter section 5a is located near a front end of the rotating shaft 5. The large-diameter section 5b is located behind the small-diameter section 5a, and the diameter of the large-diameter section 5b is larger than that of the small-diameter section 5a. A rear end surface 5d is planar and is located at a rear end of the large-diameter section 5b. The tapered section 5c is located between the small-diameter section 5a and the large-diameter section 5b. A front end of the tapered section 5c is connected to the small-diameter section 5a. The tapered section 5c increases in diameter as it extends backward, and a rear end of the tapered section 5c is connected to the large-diameter section 5b.

[0036] The small-diameter section 5a of the rotating shaft 5 is rotatably supported by the first radial ball bearing 19 through the first projection 4 of the motor housing 13. A rear end section of the large-diameter section 5b is inserted into the insertion hole 15b of the stationary block 15 and extends into the second projection 15a. In the second projection 15a, the rear end section of the large-diameter section 5b is rotatably supported by the second radial ball bearing 27. Thus, the rotating shaft 5 is rotatable about the axis of rotation O in the housing 1. The sealing element 29 provides a seal between the stationary block 15 and the rotating shaft 5.

[0037] On the rotating shaft 5, an eccentric pin 50 is fixed to the large-diameter section 5b. The eccentric pin 50 is positioned eccentrically to the axis of rotation O at the rear end face 5d. The eccentric pin 50 is columnar in shape with a diameter smaller than that of the rotating shaft 5 and extends backward from the rear end face 5d. When the rear end section of the large-diameter section 5b is inserted into the insertion hole 15b, the eccentric pin 50 engages in the second projection 15a. The eccentric pin 50 engages with a bushing 50a at the second projection 15a.

[0038] In the rotating shaft 5, a counterweight 33 is integrally formed with the large-diameter section 5b. The counterweight 33 is arranged in the large-diameter section 5b at a position eccentric to the axis of rotation O. In particular, the counterweight 33 is arranged at a position that is away from the eccentric pin 50 via the axis of rotation O.

[0039] Although a detailed description has been omitted, the counterweight 33 is essentially formed in a leaf-shaped plate form. The counterweight 33 extends in the radial direction of the rotating shaft 5 to point away from the large-diameter section 5b. The radial direction of the rotating shaft 5 is a direction perpendicular to the axis of rotation O. That is, the counterweight 33 extends from the large-diameter section 5b to the first circumferential wall 13b of the motor housing 13. When the rotating shaft 5 is arranged in the housing 1, the counterweight 33 is located in the motor chamber 17. Specifically, the counterweight 33 is located between the stationary block 15 and the motor 7 in the motor chamber 17. It should be noted that the shape of the counterweight 33 may be appropriately designed.

[0040] Motor 7 is mounted in motor chamber 17. Here, motor 7 is shown in front of the counterweight 33 in motor chamber 17. Motor 7 has a stator 7a and a rotor 7b.

[0041] The stator 7a has a stator core 71. The stator core 71 is cylindrical and fixed to an inner circumferential surface of the first circumferential wall 13b. A coil 75 is wound around the stator core 71. In addition to coil ends 73, the coil 75 has a group block 7c, a first cable 701, a second cable 702, and a third cable 703, as shown in Fig. Figure 6 is shown. Group block 7c is an example of the “terminal box” in the present invention. Each of the first to third cables 701 to 703 is an example of the “cable” in the present invention.

[0042] As in Fig. As shown in Figure 1, the coil ends 73 of the coil 75 project from opposite ends of the stator core 71 in the forward-reverse direction of the compressor and are each formed in a ring shape. An inner circumferential section of the coil end 73 at a rear end of the coil 75 is inclined to avoid interference with the counterweight 33. It should be noted that illustrations of the group block 7c and the first to third cables 701 to 703 are omitted for clarity. Fig. 1 are omitted.

[0043] Connector terminals, which are not shown, are included in group block 7c, which is located in Fig. Figure 6 is shown. Although detailed illustrations are omitted, the first to third cables 701 to 703 extend from the coil end 73 at a front end of the coil 75 to the group block 7c. The group block 7c is connected to the coil end 73 at the front end of the coil 75 by the first to third cables 701 to 703. Furthermore, the group block 7c is located behind the projecting section 6, facing the rear end face 6a of the projecting section 6, and is connected to the hermetically sealed terminals 3c. Thus, the stator 7a is electrically connected to the inverter 3 via the group block 7c. Here, a portion of the rear end face 6a of the projecting section 6 supports the group block 7c while in contact with it.

[0044] As in Fig. As shown in Figure 1, the rotor 7b is arranged inside the stator 7a. The large-diameter section 5b of the rotating shaft 5 is fixed to the rotor 7b. The rotor 7b rotates inside the stator 7a, which rotates the rotating shaft 5 about the axis of rotation O.

[0045] The compression element 10 is, in particular, a compression mechanism of a scroll or spiral design and comprises a stationary spiral 9 and a movable spiral 11. The stationary spiral 9 is fixed to and arranged within the compressor housing 14. The stationary spiral 9 has a stationary spiral end plate 9a, a stationary spiral circumferential wall 9b, and a stationary spiral wall 9c.

[0046] The fixed spiral end plate 9a is located at a rear end of the fixed spiral 9 and is disc-shaped. A second discharge recess 9d and a discharge port 9e are formed in the fixed spiral end plate 9a. The second discharge recess 9d is recessed into a rear end face of the fixed spiral end plate 9a in the forward direction of the compressor. When the fixed spiral 9 is fixed to the compressor housing 14, the second discharge recess 9d faces the first discharge recess 14d. Thus, the first discharge recess 14d interacts with the second discharge recess 9d to form a discharge chamber 35. The discharge chamber 35 is connected to the oil separator chamber 14c via the discharge passage 14e. The discharge port 9e extends through the fixed spiral end plate 9a in the forward-reverse direction of the compressor to the discharge chamber 35.

[0047] A discharge leaf valve 38 and a bracket 39 are fixed to the fixed spiral end plate 9a by a screw 37. The screw 37, the discharge leaf valve 38, and the bracket 39 are arranged in the discharge chamber 35. The discharge leaf valve 38 is elastically deformed to open and close the discharge port 9e. The bracket 39 accommodates a certain amount of elastic deformation of the discharge leaf valve 38.

[0048] The fixed spiral outer wall 9b is connected to an outer circumferential section of the fixed spiral end plate 9a and is formed in a tubular shape extending forward. A suction port 9f is formed in the fixed spiral outer wall 9b. The suction port 9f extends radially through the fixed spiral outer wall 9b in the direction of the fixed spiral 9. Thus, the suction port 9f is open to the inside of the compressor housing 14. The fixed spiral outer wall 9c is provided upright from a front surface of the fixed spiral end plate 9a and is formed integrally with the fixed spiral outer wall 9b within the fixed spiral outer wall 9b.

[0049] An oil supply passage 9g is also formed in the stationary spiral 9. The oil supply passage 9g extends through the stationary spiral end plate 9a and the stationary spiral circumferential wall 9b. With this configuration, the oil supply passage 9g is open at a rear end at the rear end face of the stationary spiral end plate 9a and at a front end at the front end face of the stationary spiral circumferential wall 9b. The oil supply passage 9g is connected to the oil separator chamber 14c via the filter 23. It should be noted that one shape of the oil supply passage 9g may be appropriate.

[0050] The movable spiral 11 is arranged in the compressor housing 14 and is located between the stationary spiral 9 and the stationary block 15. The movable spiral 11 has a movable spiral end plate 11a and a movable spiral wall 11b. The movable spiral end plate 11a is located at a front end of the movable spiral 11 and is disk-shaped. The bushing 50a is rotatably supported by a third radial ball bearing 45 through the movable spiral end plate 11a. Thus, the movable spiral 11 is connected to the rotating shaft 5 at a position eccentric to the axis of rotation O by the bushing 50a and the eccentric pin 50. The movable spiral spiral wall 11b is provided upright from a front surface of the movable spiral end plate 11a and extends to the fixed spiral end plate 9a.

[0051] Rings 47 of the same number as the anti-rotation pins 31 are provided at the movable spiral end plate 11a. A feed hole 11d is open at a rear end of the movable spiral wall 11b and is located near the center of the movable spiral wall 11b. The feed hole 11d extends through the movable spiral wall 11b and also through the movable spiral end plate 11a in the forward-reverse direction of the compressor.

[0052] The stationary spiral 9 and the movable spiral 11 are engaged with each other. Through this engagement, the stationary spiral end plate 9a, the stationary spiral spiral wall 9c, the movable spiral end plate 11a, and the movable spiral spiral wall 11b form a compression chamber 49 between the stationary spiral 9 and the movable spiral 11. The compression chamber 49 changes its volume as the movable spiral 11 rotates. This causes the compression chamber 49 to communicate with the suction port 9f and the discharge port 9e.

[0053] Each of the rings 47 is coupled to a corresponding anti-rotation pin 31 by the anti-rotation pin 31 engaging in the ring 47. The anti-rotation pins 31 and the rings 47 form an anti-rotation mechanism 16. In the anti-rotation mechanism 16, each anti-rotation pin 31 rolls along an inner circumferential surface of the corresponding ring 47 while sliding, thus regulating the rotation of the movable spiral 11 and allowing the movable spiral 11 to simply rotate. The number of anti-rotation pins 31 and rings 47 forming the anti-rotation mechanism 16 can be appropriately sized, as long as each number is three or more.

[0054] A push plate 51 is provided between the movable spiral 11 and the stationary block 15. The push plate 51 is made of a thin metal plate and is in contact with the movable spiral 11 and the stationary block 15 on opposite sides. The push plate 51 can bias the movable spiral 11 backwards, i.e., towards the stationary spiral 9, by means of a restoring force during elastic deformation. The movable spiral end plate 11a interacts with the push plate 51 to form a counter-pressure chamber 53 in the second projection 15a of the stationary block 15. The counter-pressure chamber 53 is connected to the feed hole 11d.

[0055] As in Fig. As shown in Figures 2 to 4, the first attachment 4 has an attachment main body 4a, a connecting section 4b, and a feed passage 4c. Since the motor housing 13 is made of an aluminum alloy, the first attachment 4, which is formed integrally with the first front wall 13a of the motor housing 13, is also made of an aluminum alloy.

[0056] As in Fig. As shown in Figure 3, the main body of the attachment 4a corresponds to a rear section of the first attachment 4. The main body of the attachment 4a is essentially cylindrical in shape, extending around the axis of rotation O, and has a first outer circumferential surface 41, a first inner circumferential surface 42, and a wall section 43. The first outer circumferential surface 41 is an example of the "outer circumferential surface" in the present invention. The first inner circumferential surface 42 is an example of the "inner circumferential surface" in the present invention.

[0057] As in Fig. As shown in Figure 5, the first outer circumferential surface 41 corresponds to an outer surface of the main body 4a and faces the motor chamber 17. The first inner circumferential surface 42 is located in a radial direction of the main body 4a, i.e., in the radial direction of the rotating shaft 5, within the first outer circumferential surface 41. Thus, the first inner circumferential surface 42 corresponds to an inner surface of the main body 4a.

[0058] As in Fig. As shown in Figure 3, the first inner circumferential surface 42 has a engagement section 42a and a guide section 42b. An inner diameter of the engagement section 42a is a first length L1, which is larger than an outer diameter of the first radial ball bearing 19. The engagement section 42a holds the first radial ball bearing 19 while simultaneously receiving it.

[0059] The guide section 42b is located behind the engagement section 42a and is connected to it. The inner diameter of a front end of the guide section 42b, i.e., the inner diameter of a connection point between the guide section 42b and the engagement section 42a, is equal to the inner diameter of the engagement section 42a. The guide section 42b has a tapered shape with a gradually increasing diameter, such that the diameter of the guide section 42b is larger than the diameter of the engagement section 42a. Furthermore, the guide section 42b extends backward from the engagement section 42a in an axial direction of the rotating shaft 5, i.e., in the direction in which the axis of rotation O extends. As a result, the inner diameter of a rear end of the guide section 42b is larger than the inner diameter of the engagement section 42a and the outer diameter of the first radical ball bearing 19.

[0060] As in Fig. As shown in Figure 5, the wall section 43 is located in the radial direction of the rotating shaft 5 between the first outer circumferential surface 41 and the first inner circumferential surface 42. It should be noted that in Fig. 5 a form of the main body of the attachment 4a is simplified and representations of the feed passage 4c, the rotating shaft 5 and the first radial ball bearing 19 have been omitted to facilitate explanation.

[0061] As in Fig. As shown in Figure 3, the connecting section 4b is located in front of the main attachment body 4a. That is, the connecting section 4b corresponds to a front section of the first attachment 4. The connecting section 4b is connected to a front end of the main attachment body 4a. As shown in Fig. As shown in Figure 4, the connecting section 4b extends forward while increasing in diameter, such that the diameter of the connecting section 4b is larger than the outer diameter of the main body of the attachment 4a, and is connected to the rear surface 132 of the first front wall 13a. Furthermore, as shown in Fig. Figure 3 shows a recess 44 formed in the connecting section 4b. The recess 44 is recessed in a column shape that extends around the axis of rotation O. The recess 44 is connected to the engagement section 42a. The inner diameter of the recess 44 is smaller than that of the engagement section 42a.

[0062] Here, in this compressor, the diameter of the motor housing 13 is reduced to make the compressor smaller. Accordingly, in addition to the first projection 4, the protruding section 6 and the through-hole 8 are formed in the first front wall 13a, as described above. However, it is no longer possible to ensure sufficient space between the first projection 4 and the protruding section 6 and between the first projection 4 and the through-hole 8. For this reason, as described in Fig. As shown in Figure 6, an interference avoidance section 46 is formed in the first approach 4 to prevent the first approach 4 from interfering with the group block 7c when the group block 7c is connected to the hermetically sealed terminals 3c.

[0063] This interference avoidance section 46 is formed in the main attachment body 4a and the connecting section 4b on one side in the radial direction of the rotating shaft 5, where the projecting section 6, the through hole 8 and the group block 7c are located, i.e., in sections of the main attachment body 4a and the connecting section 4b in the vicinity of the projecting section 6, the through hole 8 and the group block 7c. The interference avoidance section 46 extends in the same direction as the axis of rotation O.

[0064] The interference avoidance section 46 is formed in the main attachment body 4a and the connecting section 4b, and thus the main attachment body 4a and the connecting section 4b are away from the projection section 2, the through hole 8 and the group block 7c.

[0065] When the interference-avoidance section 46 is formed, the first outer circumferential surface 41 of the main attachment body 4a and the connecting section 4b have a cutout that has a flat surface at the section where the interference-avoidance section 46 is formed. The interference-avoidance section 46 is an example of the "cutout" in the present invention. With this cutout, as shown in Fig. 4 and Fig. As shown in Figure 5, when the main body 4a is viewed from the front along the axis of rotation O, the first outer circumferential surface 41 of the main body 4a is not formed in an arc shape over its entire circumference in one circumferential direction, and the first outer circumferential surface 41 has the straight section where the interference avoidance section 46 is formed. Since, on the other hand, the first inner circumferential surface 42 is not affected by the shape of the interference avoidance section 46, there is no straight section in the first inner circumferential surface 42.

[0066] The result is, as in Fig. As shown in Figure 5, the wall thickness of wall section 43 in the main body 4a is not uniform throughout. That is, wall section 43 has a first wall section 43a, whose thickness in the radial direction of the rotating shaft 5 is a first thickness t1, and a second wall section 43b, whose thickness in the radial direction of the rotating shaft 5, at its thinnest point, is a second thickness t2. The second thickness t2 is smaller than the first thickness t1. In other words, the second wall section 43b, which is thinner than the first wall section 43a, is formed in the wall section 43 that forms the interference avoidance section 46 in the first projection 4. Strictly speaking, the wall thickness is not constant for the second thickness t2 over the entire second wall section 43b, and the wall thickness of the second wall section 43b is also changed.However, the wall thickness of the second wall section 43b is smaller than the first thickness t1 at any given section in the second wall section 43b.

[0067] As the wall thickness of the second wall section 43b decreases, the distance between the first outer circumferential surface 41 and the first inner circumferential surface 42 in the radial direction of the rotating shaft 5 becomes shorter in a section of the main body 4a where the second wall section 43b is formed, i.e., where the interference-avoidance section 46 is formed, than in the section of the main body 4a where the first wall section 43a is formed. Furthermore, the distances between the first inner circumferential surface 42 and the projection section 6, between the first inner circumferential surface 42 and the through-hole 8, and between the first inner circumferential surface 42 and the group block 7c in the radial direction of the rotating shaft 5, when the interference-avoidance section 46 is formed, become shorter than those when the first wall section 43a extends over the entire circumference of the main body 4a, i.e.,, those if the impairment avoidance section 46 is not formed (see . Fig. 6) As a result, as in Fig. As shown in Figures 4 to 6, the first approach 4, with the axis of rotation O as a reference, is an asymmetrical form in which a form on one side where the interference avoidance section 46 is formed differs from a form on a side where the interference avoidance section 46 is not formed. In other words, the first approach 4 is formed in the asymmetrical form in which a form on a right side of the drawing planes of Fig. 4 to 6 different shapes on a left side of the drawing layers Fig. 4 to Fig. 6 is.

[0068] As in Fig. As shown in Figure 4, the feed passage 4c extends in the radial direction of the rotating shaft 5 and is recessed from a rear end of the first extension 4 in the forward direction of the compressor. That is, the feed passage 4c is recessed from the extension main body 4a to the connecting section 4b. The guide section 42b is cut out by the feed passage 4c. Here, the extension main body 4a and, by extension, the first extension 4 have a cylindrical shape, and the feed passage 4c is thus formed from a first passage section 401, which is located in the radial direction of the rotating shaft 5 closer to the obstruction avoidance section 46 than the axis of rotation O, and a second passage section 402, which is located opposite the first passage section 401 via the axis of rotation O.

[0069] The first outer circumferential surface 41 is connected to the engagement section 42a of the first inner circumferential surface 42 via the feed passage 4c at a section of the main body 4a where the feed passage 4c is formed. Similarly, the recess 44 at the connecting section 4b is connected to an outer surface of the connecting section 4b via the feed passage 4c.

[0070] The first radial ball bearing 19 is made of steel and has an outer ring 191, an inner ring 192 and a multitude of bearing balls 193, as shown in Fig. Figure 3 shows the outer ring 191 having a second outer circumferential surface 19a, which is an outer circumferential surface of the first radial ball bearing 19. The inner ring 192 is arranged inside the outer ring 191 and has a second inner circumferential surface 19b, which is an inner circumferential surface of the first radial ball bearing 19. The bearing balls 193 are each spherical and are positioned between the outer ring 191 and the inner ring 192.

[0071] An outer diameter of the outer ring 191, i.e., a diameter of the second outer circumferential surface 19a of the first radial ball bearing 19, is smaller than the inner diameter of the engagement section 42a. Furthermore, an inner diameter of the inner ring 192, i.e., a diameter of the second inner circumferential surface 19b of the first radial ball bearing 19, is smaller than an outer diameter of the small-diameter section 5a of the rotating shaft 5. This means that the outer diameter of the first radial ball bearing 19 is smaller than an inner diameter of the main body 4a, and the inner diameter of the first radial ball bearing 19 is smaller than the outer diameter of the small-diameter section 5a.

[0072] The first radial ball bearing 19 is mounted to the rotating shaft 5 via the small-diameter section 5a, which is inserted through the inner ring 192. Since, as described above, the inner diameter of the first radial ball bearing 19 is smaller than the outer diameter of the small-diameter section 5a, the small-diameter section 5a is press-fitted into the inner ring 192 in this compressor. As a result, the first radial ball bearing 19 is mounted to the small-diameter section 5a. Thus, in this compressor, the small-diameter section 5a of the rotating shaft 5 is fixed to the second inner circumferential surface 19b of the first radial ball bearing 19 by a press fit.

[0073] The first radial ball bearing 19, mounted on the rotating shaft 5, extends into the main body 4a in the forward direction of the compressor. Here, in the main body 4a, the guide section 42b directs the first radial ball bearing 19 to the engagement section 42a. As described above, the inner diameter of the engagement section 42a is larger than the outer diameter of the first radial ball bearing 19. Therefore, when the first radial ball bearing 19 enters the engagement section 42a in this compressor, it does not need to be press-fitted into the engagement section 42a.

[0074] With this configuration, the second outer circumferential surface 19a of the first radial ball bearing 19 is fitted into the engagement section 42a of this compressor, with a clearance between the second outer circumferential surface 19a and the engagement section 42a. Thus, the first projection 4 holds the first radial ball bearing 19 in a position where it is received in the engagement section 42a. The first radial ball bearing 19 rotatably supports the rotating shaft 5 while being held by the first projection 4.

[0075] In the compressor with the configuration described above, a refrigerant gas at low pressure and low temperature, flowing through the evaporator, is drawn into the motor chamber 17 through the suction opening 13c. That is, the motor chamber 17 also serves as a suction chamber in this compressor. It should be noted that the refrigerant gas drawn into the motor chamber 17 contains a lubricating oil, which is not shown.

[0076] Inverter 3 converts a direct current supplied by the battery into alternating current via the switching element 3b and supplies the alternating current power to the stator 7a. In this way, inverter 3 controls the operation of the motor 7. This rotates the rotor 7b in the motor chamber 17 together with the rotating shaft 5 around the axis of rotation O.

[0077] When the movable spiral 11 rotates in the compression section 10, the movable spiral end plate 11a slides against a tip of the fixed spiral wall 9c, and the fixed spiral wall 9c and the movable spiral wall 11b slide against each other. Here, the movable spiral 11 is prevented from rotating by the anti-rotation mechanism 16 and simply rotates. As the movable spiral 11 rotates in this way, the refrigerant gas in the motor chamber 17 flows through the suction passages 55 to the suction port 9f and is drawn from the suction port 9f into the compression chamber 49. The volume of the compression chamber 49 is reduced by the rotation of the movable spiral 11, which compresses the refrigerant gas in the compression chamber 49.

[0078] The refrigerant gas, compressed at high pressure in the compression chamber 49, is discharged through the discharge port 9e to the discharge chamber 35 and then flows from the discharge chamber 35 through the discharge passage 14e to the oil separator chamber 14c. The lubricating oil is separated from this refrigerant gas at high pressure as the refrigerant gas moves back and forth between the outer circumferential surface of the oil separator cylinder 21 and the inner circumferential surface of the oil separator chamber 14c. In this state, the refrigerant gas flows through the oil separator cylinder 21 and is discharged from the discharge opening 14f.

[0079] On the other hand, the lubricating oil, separated from the refrigerant gas, is stored in the oil separator chamber 14c. This lubricating oil then flows through the filter 23 and the oil supply passage 9g and is supplied to the sliding section between the stationary spiral 9 and the movable spiral 11, so that the sliding section in between is lubricated by the lubricating oil. Furthermore, the lubricating oil that has flowed through the oil supply passage 9g is not only supplied between the second radial ball bearing 27 and the rotating shaft 5, but also into the motor chamber 17.

[0080] A portion of the lubricating oil in the motor chamber 17 is supplied through the feed passage 4c of the first section 4 to the first radial ball bearing 19 and between the first radial ball bearing 19 and the small-diameter section 5a of the rotating shaft 5. Thus, the first radial ball bearing 19 and the rotating shaft 5 are lubricated.

[0081] A portion of the refrigerant gas, compressed at high pressure in the compression chamber 49, flows through the inlet hole 11d and is fed to the counter-pressure chamber 53. This increases the pressure in the counter-pressure chamber 53. As a result, the movable spiral 11 is biased towards the compression chamber 49 by the pressure in the counter-pressure chamber 53 via the thrust plate 51. The movable spiral 11 is also biased towards the compression chamber 49 by an elastic force exerted by the thrust plate 51. Accordingly, in this compressor, the movable spiral 11 is prevented from rotating in a state where it is inclined with respect to the axis of rotation O.

[0082] In this compressor, the diameter of the motor housing 13 is reduced to make the compressor smaller. This greatly facilitates the installation of the compressor on a vehicle. As the diameter of the motor housing 13 is reduced in this way, the distances between the first projection 4 and the protruding section 6, between the first projection 4 and the through-hole 8, and, by extension, the distance between the first projection 4 and the group block 7c are shortened, which is unavoidable. Since the interference-avoidance section 46 is formed in the first projection 4 in this compressor, the first projection 4 hardly interferes with the group block 7c. With this configuration, the group block 7c is easily connected to the hermetically sealed terminals 3c.In this compressor, it is also prevented that a connection fault between the group block 7c and the hermetically sealed terminals 3c is caused by an impairment of the first approach 4 with the group block 7c.

[0083] Since, on the other hand, the interference avoidance section 46 is formed in the first projection 4, the wall thickness of the wall section 43 in the projection main body 4a of the first projection 4 is not uniform. That is, the wall section 43 has the first wall section 43a and the second wall section 43b, and the wall thickness of the second wall section 43d is less than that of the first wall section 43a. Accordingly, the distance between the first outer circumferential surface 41 and the first inner circumferential surface 42 in the radial direction of the rotating shaft 5 in the section of the projection main body 4a where the second wall section 43b is formed, i.e., the section of the main body 4a where the interference-avoidance section 46 is formed, is shorter, and by extension, the distances between the first inner circumferential surface 42 and the projection section 6, between the first inner circumferential surface 42 and the through-hole 8, and between the first inner circumferential surface 42 and the group block 7c in the radial direction of the rotating shaft 5 are shorter when the interference-avoidance section 46 is formed than when the first wall section 43a is formed over the entire circumference of the main body 4a, i.e., shorter when the interference-avoidance section 46 is not formed. Thus, the first projection 4 has the asymmetrical shape.

[0084] If the first radial ball bearing 19 is held by the engagement section 42a of the first projection 4, it can be assumed that the insertion section 42a is designed such that the inner diameter of the engagement section 42a is smaller than the outer diameter of the first radial ball bearing 19, and that the first radial ball bearing 19 is pressed into the engagement section 42a. However, if the wall section 43 has the first wall section 43a and the second wall section 43b, and the wall thickness of the wall section 43 as a whole is not uniform, various deformations of the first inner circumferential surface 42, which has the engagement section 42a, occur slightly during pressing in. Accordingly, the engagement section 42a is slightly stressed or distorted in the projection main body 4a. The first radial ball bearing 19 is also slightly stressed or distorted due to the stress or distortion of the engagement section 42a.Furthermore, while the first component 4 is made of an aluminum alloy, the first radial ball bearing 19 is made of steel, and the coefficient of thermal expansion of the first component 4 is therefore different from that of the first radial ball bearing 19. These properties also cause the first radial ball bearing 19 to be slightly preloaded due to the tension of the engagement section 42a. As well as the roundness of the second outer circumferential surface 19a and the second inner circumferential surface 19d of the first radial ball bearing 19 decreases for these reasons, the fatigue life of the first radial ball bearing 19 decreases, raising concerns that the first radial ball bearing 19 may not be able to adequately support the rotating shaft 5.

[0085] In this respect, the second outer circumferential surface 19a of the first radial ball bearing 19 in this compressor is fitted with the clearance between the second outer circumferential surface 19a and the engagement section 42a in the engagement section 42a of the main body 4a. With this configuration, even if the first extension 4 has an asymmetrical shape and the wall thickness of the wall section 43 of the main body 4a is not uniform, there is no problem with the first radial ball bearing 19 being held by the first extension 4 in this compressor. That is, if the first radial ball bearing 19 is held by the engagement section 42a in this compressor, the first radial ball bearing 90 is hardly subjected to any preload or distortion. As a result, the fatigue life of the first radial ball bearing 19 is increased, and by extension, the fatigue life of the compressor is also increased.

[0086] In this compressor, the small-diameter section 5a of the rotating shaft 5 is pressed into and fixed to the second inner circumferential surface 19b of the first radial ball bearing 19. Both the first radial ball bearing 19 and the rotating shaft 15 are made of steel, and their coefficients of thermal expansion are therefore the same. Consequently, the small-diameter section 5a and the second inner circumferential surface 19b are hardly subjected to stress or distortion due to thermal expansion and contraction. Furthermore, to ensure proper rotation of the rotating shaft 5, which incorporates the small-diameter section 5a, the cross-section of the rotating shaft 5, perpendicular to the direction in which the axis of rotation O extends, is formed in a substantially perfect circle, which is essential.If, with this shape, the shape of the second inner circumferential surface 19b is influenced by the shape of the small-diameter section 5a due to an interference fit, the shape of the second inner circumferential surface 19b resembles a perfect circle, as before the influence. Thus, in this compressor, the small-diameter section 5a is fitted into the second inner circumferential surface 19b by the interference fit, so that the first radial ball bearing 19 adequately supports the rotating shaft 5 with the second inner circumferential surface 19b. As a result, in this compressor, there is hardly any runout of the rotating shaft 5, so that any noise generated during the operation of the compressor is suppressed.

[0087] Thus, the compressor of the first embodiment has a high durability and low noise level, while the compressor is smaller.

[0088] In particular, the first approach 4 in this compressor has the supply passage 4c, and thus the lubricating oil flows through the supply passage 4c and is adequately supplied to the first radial ball bearing 19 and the rotating shaft 5. Due to this lubricating oil, hardly any friction is generated between the first radial ball bearing 19 and the rotating shaft 5. In this compressor, this also improves the service life of the first radial ball bearing 19 and enables the first radial ball bearing 19 to adequately support the rotating shaft 5.

[0089] Furthermore, the first inner circumferential surface 42 of the first attachment 4 in this compressor has the guide section 42b. When the first radial ball bearing 19 is held by the engagement section 42a in this compressor, the first radial ball bearing 19, which is mounted on the rotating shaft 5, enters the engagement section 42a in the forward direction of the compressor. The rotating shaft 5 is also fixed to the rotor 7b. Accordingly, the rotating shaft 5 is magnetically influenced by the rotor 7b and by its extension through the motor 7, and thus, when the first radial ball bearing 19 enters the engagement section 42a, the rotating shaft 5 and the first radial ball bearing 19 are slightly inclined with respect to the axis of rotation O.In this respect, the guide section 42b of this compressor has a tapered shape that gradually decreases with respect to its inner diameter. The guide section 42b extends towards the first inner circumferential surface 42 in the direction in which the axis of rotation O extends, and the guide section 42b thus guides the first radial ball bearing 19 appropriately in the engagement section 42a, while correcting the inclined positions of the rotating shaft 5 and the first radial ball bearing 19. As a result, the first radial ball bearing 19 of this compressor easily enters the engagement section 42a while remaining parallel to the direction in which the axis of rotation O extends. Therefore, the compressor is manufactured with low friction. (Second embodiment)

[0090] In the compressor of the second embodiment, instead of the first approach 4, there is a first approach 40, which is in Fig.The first projection 40 is formed in the first front wall 13a, as shown in Figure 7. The first projection 40 is also an example of the "projection" in the present invention. The first projection 40 has a first inner circumferential surface 48, which is formed from the engagement section 42a and a guide section 48a. Although not shown, the interference-avoidance section 46 is also formed in the first projection 40. As a result, in the first projection 40, the distance between the first outer circumferential surface 41 and the first inner circumferential surface 48 in the radial direction of the rotating shaft 5 is shorter in a section of the first projection 40 where the interference-avoidance section 46 is formed than in a section of the first projection 40 where the interference-avoidance section 46 is not formed. That is, the first projection 40 has an asymmetrical shape.

[0091] The guide section 48a is located downstream of the engagement section 42a and is connected to it. The guide section 48a has a first tapered section 411, a second tapered section 412, and a connecting section 413. The first tapered section 411 corresponds to a leading section of the guide section 48a. The first tapered section 411 is connected to the engagement section 42a. The inner diameter of a leading end of the first tapered section 411, i.e., the inner diameter of a connection point of the first tapered section 411 with the engagement section 42a, is equal to the inner diameter of the engagement section 42a.The first tapered section 411 has a taper shape that gradually increases in diameter beyond the diameter of the engagement section 42a as the first tapered section 411 extends backwards from the engagement section 42a in the direction of the axis of rotation O. As a result, the inner diameter of a rear end of the first tapered section 411 is a first inner diameter L11, which is larger than the inner diameter of the engagement section 42a and the outer diameter of the first radial ball bearing 19. This means that the maximum inner diameter of the first tapered section 411 is the first inner diameter L11.

[0092] The second tapered section 412 is located behind and away from the first tapered section 411. The second tapered section 412 corresponds to a rear section of the guide section 48a. The diameter of the second tapered section 412 gradually increases beyond the maximum inner diameter of the first tapered section 411 as it extends backward away from the first tapered section 411 in the direction of rotation O. That is, the minimum inner diameter of the second tapered section 412 is the first inner diameter L11, and the diameter of the second tapered section 412 gradually increases from the first inner diameter L11 to a second inner diameter L12 as it extends away from the first tapered section 411 in the direction of rotation O.This means that the maximum inner diameter of the second tapered section 412 is the second inner diameter L12. A rear end of the second tapered section 412 is connected to a rear end of the main body 4a.

[0093] The connecting section 413 is located between the first tapered section 411 and the second tapered section 412. A front end of the connecting section 413 is connected to the first tapered section 411, and a rear end of the connecting section 413 is connected to the second connecting section 412. Thus, the first tapered section 411 is connected to the second tapered section 412 by the connecting section 413. Here, the connecting section 413 extends in a straight line between the first tapered section 411 and the second extension section 412 without increasing or decreasing the diameter of the connecting section 413. That is to say,, the first tapered section 411 and the second tapered section 412 are connected to each other by the connecting section 413, which has a constant diameter equal to the first inner diameter L11, which is the maximum inner diameter of the first tapered section 411.

[0094] Furthermore, in a section of the guide section 48a, where the feed passage 4c is formed, the first tapered section 411, the second tapered section 412, and the connecting section 413 are cut out by the feed passage 4c. Other components of the compressor in the second embodiment, which have other components of the first design 40, are identical to those of the compressor in the first embodiment. Identical components are designated by the same reference numerals, and detailed descriptions of the components are omitted.

[0095] In this compressor, the first tapered section 411 and the second tapered section 412 are connected by the connecting section 413 of the guide section 48a, which has a constant diameter equal to the first inner diameter L11. Thus, during a process in which the rotating shaft 5 and the first radial ball bearing 19 pass through the connecting section 413, the inclined positions of the rotating shaft 5 and the first radial ball bearing 19 are appropriately corrected, even if the positions of the rotating shaft 5 and the first radial ball bearing 19 are inclined with respect to the axis of rotation O. The first tapered section 411 then guides the rotating shaft 5 and the first radial ball bearing 19, which pass through the connecting section 413, into the engagement section 42a, while the diameter of the first tapered section 411 decreases.Thus, the positions of the rotary shaft 5 and the first radial ball bearing 19 during the process in which the rotary shaft 5 and the first radial ball bearing 19 pass through the first tapered section 411 are corrected even more precisely by the first tapered section 411.

[0096] The guide section 48a has the first tapered section 411, the second tapered section 412, and the connecting section 413. Thus, in this compressor, a sufficient distance of the guide section 48a in the direction in which the axis of rotation O extends, i.e., a sufficient length of the guide section 48a in the direction in which the axis of rotation O extends, is adequately ensured. Accordingly, in this compressor, the guide section 48a further guides the first radial ball bearing 19 appropriately into the engagement section 42a. Therefore, this compressor is easily manufactured. Other processes of this compressor of the second embodiment are the same as those of the compressor in the first embodiment.

[0097] The present invention has been described in the above description based on the first and second embodiments. However, the present invention is not limited to the first and second embodiments described above and may be modified within the scope of the present invention where appropriate.

[0098] For example, in the compressor of the first embodiment, the first radial ball bearing 19 corresponds to the “bearing” in the present invention; however, the present invention is not limited thereto. A plain bearing can be used as the “bearing” in the present invention. This applies to the compressor of the second embodiment.

[0099] In the compressor of the first embodiment, the interference avoidance section 46 is formed in the first extension 4, and thus the first extension 4 has an asymmetrical shape; however, the present invention is not limited thereto. The first outer circumferential surface 41 of the extension main body 4a can be integrated with a part of the other element formed in the first front wall 13a, so that the first extension 4 can have an asymmetrical shape. That is, in this case too, the first extension 4 has the first outer circumferential surface 41, which varies with respect to a distance from the first inner circumferential surface 42 in the radial direction of the rotating shaft 5. This applies to the compressor of the second embodiment.

[0100] In the compressor of the first embodiment, the feed passage 4c has the first passage section 401 and the second passage section 402; however, the present invention is not limited thereto. The feed passage 4c can have only one of the first passage section 401 and the second passage section 402, or it can have three or more passage sections. This applies to the compressor of the second embodiment.

[0101] In the compressor of the first embodiment, the compression element 10 is a compression element of a scroll or spiral design; however, the present invention is not limited to this. The compression element 10 can be a compression element of a vane cell design or the like. If the compression element 10 is a compression element of a scroll design, it can be a compression element of a rotating scroll design in which both spirals are rotated. This applies to the compressor of the second embodiment.

[0102] In the compressor of the first embodiment, the compression element 10 compresses the refrigerant gas as the fluid; however, the present invention is not limited to this. The compression element 10 can compress a fluid such as air. This applies to the compressor of the second embodiment.

[0103] The present description also includes the following inventions. (Supplementary Note 1)

[0104] An electric compressor comprising a housing, a rotating shaft rotatably supported in the housing, a motor configured to rotate the rotating shaft, and a compression element configured to compress a fluid by rotating the rotating shaft, wherein the housing has a projection formed in a tubular shape extending axially from the rotating shaft to the motor, and the projection has an inner circumferential surface in which a bearing is provided to support the rotating shaft, is characterized in that the projection has an asymmetrical shape and an outer circumferential surface which varies with respect to a distance from the inner circumferential surface in a radial direction of the rotating shaft, and the rotating shaft is pressed into the bearing, and the bearing is fitted into the inner circumferential surface with a clearance between the bearing and the inner circumferential surface. (Supplementary Note 2)

[0105] The electric compressor according to supplementary note 1 is characterized in that the attachment has a supply passage which extends from the outer circumferential surface in the radial direction of the rotating shaft to the inner circumferential surface and through which lubricating oil is supplied to the bearing. (Supplementary Note 3)

[0106] The electric compressor according to supplementary note 1 or 2 is characterized in that an inverter is provided in the housing, which is located opposite the compression part and is electrically connected to the motor, which is arranged between the inverter and the compression part; the housing has a motor chamber in which the motor is received, an inverter chamber in which the inverter is received, and a partition wall by which the motor chamber is separated from the inverter chamber and in which the extension is formed; the partition wall has a through-hole in which a hermetically sealed terminal is inserted; the motor is connected to the inverter by the hermetically sealed terminal; the motor has a stator core around which a coil is wound and a rotor which rotates integrally with the drive shaft; the coil has coil ends that project from opposite ends of the stator core.a terminal box electrically connected to the hermetically sealed terminal, and having a cable extending from one of the coil ends to the terminal box, and the outer circumferential surface having a cutout, and at least one of the distances between the inner circumferential surface and the through-hole and between the inner circumferential surface and the terminal box, when the cutout is formed, differs from the distance when the cutout is not formed, thus forming the projection in the asymmetrical shape. (Supplementary Note 4)

[0107] The electric compressor according to one of the supplementary notes 1 to 3 is characterized in that the inner circumferential surface has a engagement section in which the bearing with the clearance is fitted, and a guide section which guides the bearing into the engagement section, and the guide section has a first tapered section which gradually increases in diameter over a diameter of the engagement section, and which extends away from the engagement section in the axial direction of the rotating shaft, a second tapered section which is located away from the first tapered section in the axial direction of the rotating shaft and which gradually increases in diameter over a maximum inner diameter of the first tapered section, and which extends away from the first tapered section, and a connecting section.which is located between the first tapered section and the second tapered section and has a constant inner diameter equal to the maximum inner diameter of the first tapered section and through which the first tapered section and the second tapered section are connected. (Supplementary Note 5)

[0108] The electric compressor according to one of the supplementary notes 1 to 4 is characterized in that the bearing has an inner ring in which the rotating shaft is pressed in, and an outer ring which is fitted into the inner circumferential surface with a clearance between the inner circumferential surface and the outer ring, and a plurality of bearing balls, each of which has a spherical shape and is provided between the inner ring and the outer ring. Industrial applicability

[0109] The present invention can be used for an air conditioning system of a vehicle or similar. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2012-057504

[0002] JP 2012 - 057 504 A

[0002]

Claims

[1] Electric compressor with: a housing (1); a rotary shaft (5) rotatably supported in the housing (1); a motor (7) configured to rotate the rotary shaft (5); and a compression part (10) configured to compress a fluid by the rotation of the rotary shaft (5), wherein the housing (1) has a projection (4, 40) formed in a tubular shape projecting in an axial direction of the rotary shaft (5) toward the motor (7), and the projection (4, 40) has an inner peripheral surface (42, 48) in which a bearing (19) supporting the rotary shaft (5) is provided, characterized by , that the projection (4, 40) has an asymmetrical shape and has an outer peripheral surface (41) which varies in distance from the inner peripheral surface (42, 48) in a radial direction of the rotary shaft (5), and the rotary shaft (5) is pressed into the bearing (19) and the bearing (19) is fitted at the inner peripheral surface (42, 48) with a clearance between the bearing (19) and the inner peripheral surface (42, 48). [2] Electric compressor according to claim 1, characterized by that the projection (4, 40) has a supply passage (4c) which extends from the outer peripheral surface (41) in the radial direction of the rotary shaft (5) to the inner peripheral surface (42, 48) and through which a lubricating oil is supplied to the bearing (19). [3] Electric compressor according to claim 1 or 2, characterized by , that an inverter (3) is provided in the housing (1), which is located opposite to the compression part (10) and is electrically connected to the motor (7), which is arranged between the inverter (3) and the compression part (10), the housing (1) has a motor chamber (17) in which the motor (7) is accommodated, an inverter chamber (18) in which the inverter (3) is accommodated, and a partition wall (13a) by which the motor chamber (17) is separated from the inverter chamber (18) and in which the projection (4, 40) is formed, the partition wall (13a) has a through hole (8) in which a hermetically sealed terminal (3c) is inserted, the motor (7) is connected to the inverter (3) through the hermetically sealed terminal (3c), the motor (7) has a stator core (71) around which a coil (75) is wound, and a rotor (7b) which rotates integrally with the rotating shaft (5), the coil (75) has coil ends (73) projecting from opposite ends of the stator core (71), a terminal box (7c) electrically connected to the hermetically sealed terminal (3c), and a cable (701, 702, 703) extending from one of the coil ends (73) to the terminal box (7c), and the outer peripheral surface (41) has a cutout (46), and at least one of a distance between the inner peripheral surface (42, 48) and the through hole (8) and a distance between the inner peripheral surface (42, 48) and the terminal box (7c) when the cutout (46) is formed is different in the radial direction of the rotary shaft (5) from the distance when the cutout (46) is not formed, forming the boss (4, 40) in the asymmetric shape. [4] Electric compressor according to one of claims 1 to 3, characterized by , that the inner peripheral surface (42, 48) has an engagement portion (42a) in which the bearing (19) is fitted with the clearance, and a guide portion (48a) which guides the bearing (19) into the engagement portion (42a), and the guide section (48a) has the following: a first tapered portion (411) gradually increasing in diameter over a diameter of the engaging portion (42a), and the first tapered portion (411) extends away from the engaging portion (42a) in the axial direction of the rotary shaft (5); a second tapered portion (412) located in the axial direction of the rotary shaft (5) away from the first tapered portion (411) and gradually increasing in diameter beyond a maximum inner diameter of the first tapered portion (411), as the second tapered portion (412) extends away from the first tapered portion (411); and a connecting portion (413) located between the first tapered portion (411) and the second tapered portion (412) and having a constant inner diameter equal to the maximum inner diameter of the first tapered portion (411), and by which the first tapered portion (411) and the second tapered portion (412) are connected. [5] Electric compressor according to one of claims 1 to 4, characterized by that the bearing (19) has an inner ring (192) into which the rotary shaft (5) is pressed, and an outer ring (191) which is fitted at the inner peripheral surface (42, 48) with the clearance between the inner peripheral surface (42, 48) and the outer ring (191), and a plurality of bearing balls (193), each having a spherical shape and provided between the inner ring (192) and the outer ring (192).

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