JP2007318962A - Rotary machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary machine in which the axial length can be shortened as compared with prior art. <P>SOLUTION: In the motor 10, a motor rotor 10R is supported rotatably for the motor stator 10S by a plain bearing 100 sliding on the outer circumferential surface of the motor rotor 10R (more specifically, a magnet cover 24) and the inner circumferential surface of the stator core 13 (more specifically, forward end face 14M of each teeth 14), and thereby the axial length of the motor 10 can be shortened as compared with a conventional motor where the opposite ends of the rotor shaft are supported by bearings. Since lubricant 90 is interposed between the outer circumferential surface of the motor rotor 10R and the inner circumferential surface of the stator core 13, the motor rotor 10R and the motor stator 10S can be protected against seizure or abrasion. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rotating machine that rotatably supports a rotor with respect to a stator by a bearing.

In the conventional rotating machine, both ends of the rotor shaft are pivotally supported by bearings (for example, ball bearings) (see, for example, Patent Document 1).
JP 2003-206878 (paragraph [0015], FIG. 1)

  By the way, in recent automobiles, various actuators powered by a rotating machine (motor) as typified by an electric power steering device are generally mounted. However, all of them are required to save installation space. ing. For this reason, development of a more compact rotating machine has been desired.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a rotating machine whose axial length can be made shorter than before.

  The rotating machine (10, 40, 50, 60, 70) according to the invention of claim 1 made to achieve the above object rotates the rotor (10R, 50R) with a bearing relative to the stator (10S, 50S). In the rotating machine (10, 40, 50, 60, 70) that is pivotally supported, the rotor side magnetic path component (23, 56) fixed to the rotor shaft (22, 54) of the rotor (10R, 50R). Of the stator and the stator (10S, 50S) and the stator-side magnetic path constituent parts (13, 51) constituting the magnetic circuit together with the rotor-side magnetic path constituent parts (23, 56). (100) with features.

  According to a second aspect of the present invention, in the rotating machine (10, 40, 50, 60, 70) according to the first aspect, the circumferential surface of the rotor-side magnetic path constituent part (23, 56) and the stator-side magnetic path constituent part It is characterized in that a lubricant (90) is interposed between the peripheral surfaces of (13, 51).

  The invention of claim 3 is characterized in that in the rotating machine (10, 40, 50, 60, 70) of claim 2, solid fine particles (91) are mixed in the lubricant (90). .

  According to a fourth aspect of the present invention, in the rotating machine (10, 40, 50, 60, 70) according to the second or third aspect, the rotor-side magnetic path component (23, 56) and the stator-side magnetic path component (13). , 51) is characterized in that a cylindrical cover (24, 41, 57) is fitted and fixed to at least one peripheral surface.

  According to a fifth aspect of the present invention, in the rotating machine (10, 40, 50, 60, 70) according to the fourth aspect, the lubricant (90) is stored on the peripheral surface of the cylindrical cover (24, 41, 57). It is characterized in that the recess (80) is formed.

  A sixth aspect of the present invention is the rotating machine (10, 40, 50, 60, 70) according to any one of the first to fifth aspects, wherein the rotor-side magnetic path component (23, 56) has a peripheral surface or a stator side. It is characterized in that it is provided with a mold member (61) having a continuous cylindrical peripheral surface molded on the peripheral surface of the magnetic path constituting part (13, 51).

  The invention of claim 7 is the rotating machine (10, 40, 50, 60, 70) according to any one of claims 1 to 6, wherein the rotating machine (10) is a brushless motor (10), and the rotor side magnet The path constituent part (23) is a ring magnet or a segment magnet (23), and the stator side magnetic path constituent part (13, 51) is a stator core (13, 13) having a plurality of teeth (14, 52) around which electric wires are wound. , 51).

  The invention of claim 8 is characterized in that, in the rotating machine (10, 40, 50, 60, 70) according to any one of claims 1 to 7, the electric power steering device is incorporated as a power source.

[Inventions of Claims 1 and 7]
According to the configuration of the first aspect, the rotor is rotatable with respect to the stator by the sliding bearing that slides between the circumferential surface of the rotor-side magnetic path constituting portion of the rotor and the circumferential surface of the stator-side magnetic path constituting portion of the stator. Since the shaft is supported, the shaft length of the rotating machine can be made shorter than the conventional one by the amount of the bearing. Here, when the rotating machine is a brushless motor, the rotor-side magnetic path constituent part is a ring magnet or a segment magnet, and the stator-side magnetic path constituent part is a stator core having a plurality of teeth around which electric wires are wound ( (Invention of Claim 7)

[Invention of claim 2]
According to the second aspect of the present invention, the circumferential surface of the rotor-side magnetic path constituent part and the peripheral surface of the stator-side magnetic path constituent part can be smoothly slid, and seizure and wear of the rotor and the stator can be prevented. it can. In addition, examples of the lubricant include lubricating oil and grease.

[Invention of claim 3]
According to the third aspect of the present invention, the lubricity between the peripheral surface of the rotor side magnetic path constituent part and the peripheral surface of the stator side magnetic path constituent part is further improved by mixing the solid fine particles with the lubricant. be able to.

[Inventions of Claims 4 and 6]
According to the fourth and sixth aspects of the present invention, the unevenness formed on the circumferential surfaces of the rotor-side magnetic path constituting portion and the stator-side magnetic path constituting portion is not caught by each other, and the rotor is smoothly rotated with respect to the stator. be able to.

[Invention of claim 5]
According to the fifth aspect of the present invention, it is possible to prevent the lubricant from running out between the peripheral surface of the rotor-side magnetic path constituent portion and the peripheral surface of the stator-side magnetic path constituent portion of the stator.

[Invention of Claim 8]
According to the invention of claim 8, the electric power steering apparatus can be made compact, and the degree of freedom of attachment to the vehicle is improved.

[First Embodiment]
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. The motor 10 (corresponding to the “rotor” of the present invention) of the present embodiment is a brushless AC motor for EPS (electric power steering device), for example, and has a stator 10S (hereinafter referred to as a motor stator) in a cylindrical case 12. 10S "), and a rotor 10R (hereinafter referred to as" motor rotor 10R ") is rotatably provided inside the motor stator 10S. The motor stator 10 </ b> S includes a stator core 13 and a plurality of coils 15. The stator core 13 is formed, for example, by laminating a plurality of silicon steel plates, and has a structure in which a plurality of teeth 14 are projected inward from the inner surface of a cylindrical body constituting the outer shell as shown in FIG. An electric wire is wound around each of these teeth 14 to form a coil 15. The front end surfaces 14M of the teeth 14 are formed by arc surfaces arranged on the same circle, and are separated from each other in the circumferential direction. The inner peripheral surface of the motor stator 10S has a plurality of irregularities due to the tip surface 14M of the teeth 14 and the slots (grooves) between the teeth 14, 14.

  The motor rotor 10 </ b> R includes a cylindrical rotor core 21 with a rotor shaft 22 passing through the center, and a plurality of segment magnets 23 are fixed to the outer surface of the rotor core 21. The rotor core 21 is formed by laminating a plurality of silicon steel plates, for example. The segment magnet 23 is a permanent magnet made of a sintered member, and has, for example, a tile structure in which a cylindrical body that can be fitted to the outside of the rotor core 21 is divided into a plurality of vertical sections. Further, each segment magnet 23 is magnetized so that the magnetic path is directed in the radial direction of the motor rotor 10R, for example, and conversely with the segment magnet 23 having NS poles from the inner side to the outer side in the radial direction, The segment magnets 23 having NS poles from the outside in the radial direction to the inside are alternately arranged in the circumferential direction of the motor rotor 10R. A cylindrical magnet cover 24 (corresponding to the “cylindrical cover” of the present invention) is fitted so as to cover the outside of the plurality of segment magnets 23. The magnet cover 24 is made of stainless steel.

  As shown in FIG. 1, the cylindrical case 12 has a cylindrical shape with bottoms at both ends, and both end portions of the rotor shaft 22 pass through through holes 12H and 12H formed at the centers of both end walls. In addition, an oil seal 25 that is in close contact with the outer peripheral surface of the rotor shaft 22 is assembled inside the large diameter portion of each through hole 12H to prevent oil leakage and dust from entering the motor 10 inside. Yes.

  And although not illustrated, both ends of the rotor shaft 22 of the motor 10 are connected to a middle portion of the steered shaft that connects the steered wheels of the vehicle via a shaft coupling (for example, Oldham coupling), An assist force for assisting the driver's steering operation is applied by the motor 10.

  Incidentally, as shown in an enlarged view in FIG. 3, the outer peripheral surface of the motor rotor 10R (specifically, the magnet cover 24) and the inner peripheral surface of the stator core 13 of the motor stator 10S (specifically, the front end surface 14M of the teeth 14). ), A slight bearing gap (for example, about 0.1 mm) is formed, and a thin film of lubricant 90 (for example, lubricating oil) is formed in the bearing gap. That is, a slide bearing 100 (so-called “fluid lubricated bearing”) using a lubricant 90 interposed in the bearing gap as a lubricating fluid is formed inside the stator core 13, and the motor rotor 10 R is connected to the motor stator 10 S by the slide bearing 100. And is pivotally supported on the same axis. Here, the lubricant 90 is preferably configured to be held in the bearing gap by surface tension or viscosity.

  As described above, according to the present embodiment, the outer peripheral surface of the motor rotor 10R (specifically, the magnet cover 24) and the inner peripheral surface of the stator core 13 (specifically, the front end surface 14M of each tooth 14) are slid. Since the motor rotor 10R is rotatably supported with respect to the motor stator 10S by the bearing 100, the shaft length of the motor 10 is made longer than that in the conventional case where both ends of the rotor shaft are supported by bearings. Can be shortened. Further, the lubricant 90 is interposed between the outer peripheral surface of the motor rotor 10R and the inner peripheral surface of the stator core 13, so that seizure and wear of the motor rotor 10R and the motor stator 10S can be prevented. Furthermore, by fitting and fixing the magnet cover 24 to the outside of the segment magnet 23, the outer peripheral surface of the motor rotor 10R becomes a smooth cylindrical surface, and the motor rotor 10R is prevented from being caught by irregularities on the inner peripheral surface of the motor stator 10S. The Thereby, the motor rotor 10R can be smoothly rotated inside the motor stator 10S.

  Note that the total dimension of the bearing gap formed between the outer peripheral surface of the motor rotor 10R and the inner peripheral surface of the stator core 13 and the thickness of the magnet cover 24 represents the air between the motor rotor and the motor stator in the conventional motor. When configured to be smaller than the gap length, the magnetic resistance is reduced as compared with the conventional one, and the motor 10 can be downsized in the radial direction.

[Second Embodiment]
A motor 40 according to this embodiment is shown in FIGS. 4 and 5. In the motor 40, a cylindrical stator core cover 41 (corresponding to the “cylindrical cover” of the present invention) is fitted and fixed to the inner peripheral surface of the stator core 13 (the tip surface 14 M of each tooth 14). A thin film of lubricant 90 is formed in a cylindrical bearing gap formed between the magnet cover 24 and the magnet cover 24. The stator core cover 41 is made of stainless steel, for example, like the magnet cover 24. Other structures are the same as those in the first embodiment, and the same portions are denoted by the same reference numerals, and redundant description is omitted. The configuration of this embodiment also provides the same effect as that of the first embodiment. Further, since both the outer peripheral surface of the motor rotor 10R and the inner peripheral surface of the motor stator 10S are formed of a smooth cylindrical surface, the assembly work of the motor rotor 10R and the motor stator 10S can be performed smoothly.

[Third Embodiment]
FIG. 6 shows an enlarged part of the motor 60 according to this embodiment. In the motor 60, a resin mold member 61 is molded inside a cylindrical body constituting the outer shell of the stator core 13. The mold member 61 closes a slot formed between the teeth 14 and 14 and covers the tip end surface 14M of each tooth 14 to form a continuous cylindrical inner peripheral surface inside the motor stator 10S. A thin film of a lubricant 90 is formed between the inner peripheral surface of the cylinder and the outer peripheral surface of the magnet cover 24 provided in the motor rotor 10R, so that the slide bearing 100 that rotatably supports the motor rotor 10R is configured. According to the structure of this embodiment, there exists an effect equivalent to the said 2nd Embodiment.

[Fourth Embodiment]
The motor 70 of this embodiment is shown in FIG. As shown in the figure, a reluctance resolver 30 is provided at one end of the motor 70 in the axial direction.

  The resolver 30 includes a rotor 30R (hereinafter referred to as “resolver rotor 30R”) that is rotatable inside a stator 30S (hereinafter referred to as “resolver stator 30S”). The stator core 31 provided in the resolver stator 30S is formed by laminating a plurality of silicon steel plates, for example, like the stator core 13 of the motor 70. A plurality of (for example, twelve) teeth 32 are formed on the inner side of the stator core 31, and a coil 33 is wound around each of the teeth 32. The distal end surface 32M of each tooth 32 is configured by an arc surface arranged on the same circle. Due to the tip end surface 32M of the teeth 32 and the slots (grooves) between the teeth 32, 32, the inner side surface of the resolver stator 30S is also provided with a plurality of irregularities.

  The resolver stator 30S is fitted and assembled in the cylindrical case 12 via the adapter 16, for example. Specifically, the adapter 16 is assembled so that its outer surface is fitted to the inner surface of the cylindrical case 12 and is in contact with the end surface of the motor stator 10S. A large inner diameter portion is provided on the inner surface of the adapter 16 on the side away from the motor stator 10S, and the resolver stator 30S is fitted and fixed inside the large inner diameter portion. Thereby, the resolver stator 30S is positioned in a state slightly separated from the motor stator 10S. Further, the end face of the adapter 16 and the resolver stator 30S opposite to the motor stator 10S is in contact with the case lid 26, whereby the resolver stator 30S, the adapter 16 and the motor stator 10S are positioned in the axial direction of the cylindrical case 12. It is fixed.

  The magnet cover 24 fitted and fixed to the motor rotor 10R is extended to the resolver 30 side and is also fitted to the outside of the resolver rotor 30R. A thin film of the lubricant 90 is also formed between the outer peripheral surface of the magnet cover 24 and the inner peripheral surface of the stator core 31 provided in the resolver stator 30S (specifically, the tip end surface 32M of the teeth 32). . According to this structure, there exists an effect equivalent to the said 1st Embodiment. In addition, since the outer peripheral surface of the resolver rotor 30R is also a smooth cylindrical surface, the outer peripheral surface of the resolver rotor 30R is prevented from being caught by irregularities on the inner peripheral surface of the resolver stator 30S.

[Fifth Embodiment]
FIG. 8 shows a reluctance motor 50 according to the present embodiment. A plurality of (for example, eight) teeth 52 are formed on a stator core 51 provided in the motor stator 50 </ b> S of the motor 50, and a coil 53 is wound around each tooth 52. On the other hand, the motor rotor 50R has a rotor shaft 54 penetrating through the center, and a plurality (for example, six) salient poles 56 ("rotor side magnetic path constituting portion" of the present invention) from the outer surface of the motor rotor 50R. ) Project radially. A cylindrical cover 57 having a cylindrical surface that passes in common through the tip surfaces of the salient poles 56 is fitted and fixed to the outer surface of the motor rotor 50R. A thin film of a lubricant 90 is formed between the outer peripheral surface of the cylindrical cover 57 and the tip end surface 52M of each tooth 52, and a slide bearing 100 is provided that rotatably supports the motor rotor 50R with respect to the motor stator 50S. ing. The cylindrical cover 57 is made of stainless steel, for example. Even with the configuration of the present embodiment, the same effects as those of the first embodiment can be obtained.

[Sixth Embodiment]
FIG. 9 shows an enlarged part of the motor 95 of the present embodiment. As shown in the figure, the motor 95 includes a cylindrical lubricating cover 24J having lubricity instead of the magnet cover 24, and a cylindrical lubricating cover 41J having lubricity instead of the stator core cover 41. The motor rotor 10R rotates relative to the motor stator 10S while the peripheral surfaces of the covers 24J and 41J are in sliding contact with each other. The lubricating covers 24J and 41J have a structure in which a lubricating oil (or grease) is impregnated in a cover main body formed of a porous body (for example, sintered metal). When the motor rotor 10R rotates, the lubricating oil oozes out from the holes in the lubricating covers 24J and 41J, and a thin oil film is formed on the sliding contact surfaces of the lubricating covers 24J and 41J. To be absorbed. That is, the sliding bearing 100 has a structure as a so-called “self-lubricating bearing (more specifically,“ oil-impregnated bearing ”). Other configurations are the same as those of the second embodiment. According to this embodiment, it is possible to perform lubrication over a relatively long period while suppressing loss of the lubricating oil. In addition, the structure provided only with either one of lubrication covers 24J and 41J may be sufficient.

[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various other than the following can be made without departing from the scope of the invention. It can be changed and implemented.

  (1) As shown in FIG. 10, if the solid fine particles 91 are mixed with lubricating oil, grease, water or the like as the lubricant 90, the lubricity between the outer peripheral surface of the motor rotor 10R and the inner peripheral surface of the motor stator 10S is further increased. Can be improved. The solid fine particles 91 are preferably fine powder of tetrafluoroethylene resin or boron nitride having relatively high lubricity.

  (2) In the first to fifth embodiments, the recess 80 for storing the lubricant 90 may be formed on the outer peripheral surface of the magnet cover 24, the outer peripheral surface of the cylindrical cover 57, and the inner peripheral surface of the stator core cover 41. Good. The concave portion 80 is, for example, a groove shape (see (A) and (B) of FIG. 11) extending parallel or obliquely to the axial direction of the motor, or a ring or spiral groove shape (( (See C) and (D)). Moreover, when each cover 24,41,57 is comprised with the porous body, it is good also considering the void | hole formed in the surface as the recessed part 80 for accumulating the lubricant 90 (refer (E) of FIG. 11). ). With such a configuration, it is possible to prevent the lubricant from running out between the outer peripheral surfaces of the motor rotors 10R and 50R and the inner peripheral surfaces of the motor stators 10S and 50S.

  (3) Of the motor rotors 10R, 50R and the motor stators 10S, 50S, the stator core cover 41 may be fitted and fixed only to the motor stators 10S, 50S. According to this configuration, since the magnet cover 24 or the cylindrical cover 57 is fixed to the motor rotors 10R and 50R that rotate, it is possible to prevent the inertia of the motor rotors 10R and 50R from being increased by the magnet cover 24 or the cylindrical cover 57. it can.

  (4) The motor rotor 10 </ b> R may include a cylindrical ring magnet instead of the segment magnet 23.

  (5) The stator core cover 41 fitted and fixed to the peripheral surface of the motor stator 10S may be a magnetic material or a non-magnetic material. Further, the magnet cover 24 and the cylindrical cover 57 fitted and fixed to the motor rotors 10R and 50R may be made of a metal other than stainless steel (for example, white metal) or a synthetic resin.

  (6) The tips of the teeth 14 and 52 provided in the motor stators 10S and 50S may be made continuous to form a continuous cylindrical inner peripheral surface by the tip surfaces 14M and 52M of the plurality of teeth 14 and 52. .

  (7) In the first to fifth embodiments, if the cylindrical case 12 is filled with the lubricant 90 (lubricating oil, water, etc.), it is possible to reliably prevent the lubricant from running out in the bearing gap.

  (8) In the first to sixth embodiments, the present invention is applied to the inner rotor type motors 10 and 50. However, the present invention may be applied to an outer rotor type motor.

  (9) In the third embodiment, the cylindrical inner peripheral surface is formed by molding the mold member 61 on the inner peripheral surface of the stator core 13 (the tip surface 14M of each tooth 14). The molding member 61 may be molded outside the segment magnet 23 to form a continuous and smooth cylindrical outer peripheral surface.

  (9) When the distal end surface 14M of each tooth 14 is an arc surface arranged in the same circle as in the first embodiment, slots formed between adjacent teeth 14 and 14 in the stator core 13 A mold member is molded only, and a cylindrical inner peripheral surface is formed by an inner surface exposed to the inside of the stator core 13 between adjacent teeth 14 and 14 of the mold member and a tip surface 14M of each tooth 14. May be.

  (10) In the first to fifth embodiments, for example, a metal washer is applied to cover both openings of the bearing gap to prevent leakage of the lubricant 90 from the bearing gap. Good.

  (11) In the sixth embodiment, the lubricating covers 24J and 41J have a structure in which a porous body is impregnated with lubricating oil. For example, the lubricating covers 24J and 41J are compared with the peripheral surface of a cover body formed of metal, synthetic resin, or ceramics. It may be configured to be coated with a solid material having high mechanical lubricity (for example, graphite, molybdenum disulfide, fluorine resin) or the like, or the lubricating covers 24J and 41J themselves may be formed of a solid material having high lubricity. Such a configuration eliminates the need for a lubricant such as lubricating oil or grease, thereby eliminating the need for replenishment when the lubricant is lost and improving the degree of freedom of equipment that can be incorporated as a power source. The lubricating covers 24J and 41J and the lubricant 90 may be used in combination.

  (12) In the above embodiment, the motor is exemplified as the rotating machine according to the present invention, but the present invention may be applied to an electric motor.

1 is a side sectional view of a motor according to a first embodiment of the present invention. AA sectional view in FIG. Partial enlarged view of motor Side sectional view of a motor according to a second embodiment Partial enlarged view of motor Partial enlarged view of the motor according to the third embodiment Side sectional view of a motor according to a fourth embodiment Plan sectional view of a motor according to a fifth embodiment Partial enlarged view of the motor according to the sixth embodiment Partial enlarged view of a motor according to another embodiment (1) Side view of magnet cover and cylindrical cover according to other embodiment (2)

Explanation of symbols

10, 40, 50, 60, 70, 95 Motor 10R, 50R Motor rotor 10S, 50S Motor stator 13, 51 Stator core (stator side magnetic path component)
14, 52 Teeth 15, 53 Coil 22, 54 Rotor shaft 23 Segment magnet (rotor side magnetic path component)
24 Magnet cover (cylindrical cover)
24J Lubrication cover 41 Stator core cover (cylindrical cover)
41J Lubrication cover 56 Salient pole (rotor side magnetic path component)
57 Cylindrical cover 61 Mold member 80 Concave portion 90 Lubricant 91 Solid particulate 100 Sliding bearing

Claims (8)

In a rotating machine that rotatably supports a rotor by a bearing with respect to a stator,
The peripheral surface of the rotor side magnetic path constituent part fixed to the rotor shaft of the rotor and the peripheral surface of the stator side magnetic path constituent part constituting the magnetic circuit together with the rotor side magnetic path constituent part of the stator are slid. A rotating machine comprising a sliding bearing.   2. The rotating machine according to claim 1, wherein a lubricant is interposed between a peripheral surface of the rotor-side magnetic path constituent part and a peripheral surface of the stator-side magnetic path constituent part.   The rotating machine according to claim 2, wherein solid lubricant is mixed in the lubricant.   4. The rotating machine according to claim 2, wherein a cylindrical cover is fitted and fixed to at least one peripheral surface of the rotor-side magnetic path constituting portion and the stator-side magnetic path constituting portion.   The rotating machine according to claim 4, wherein a recess for storing the lubricant is formed on a peripheral surface of the cylindrical cover.   6. The molding member according to claim 1, further comprising a molding member molded on the circumferential surface of the rotor-side magnetic path constituting portion or the circumferential face of the stator-side magnetic path constituting portion and having a continuous cylindrical circumferential surface. The rotating machine according to Crab. The rotating machine is a brushless motor;
The rotor side magnetic path constituent part is a ring magnet or a segment magnet,
The rotating machine according to any one of claims 1 to 6, wherein the stator side magnetic path constituent part is a stator core having a plurality of teeth around which electric wires are wound. The rotating machine according to claim 1, wherein the rotating machine is incorporated as a power source in the electric power steering apparatus.

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