JP2009303289A - Rotary electric machine for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary electric machine for vehicle, which can enhance detection accuracy in detecting the position of a rotor and can secure cooling performance and water resistance around a slip ring. <P>SOLUTION: An AC generator 100 for a vehicle includes: a rotor 4 including a rotary shaft 44 with a pair of slip rings 47, 48; a pair of brushes 61, 62 in slide contact with each slip ring; a brush holder 200, having an accommodation part for accommodating the pair of brushes formed therein; a brush device 6, having a cover member 250 for covering the brush holder 200 and the slip rings 47, 48; and a part 71 to be detected and a detection part 72 for detecting the rotary position of the rotor 4. The cover member 250 has an open part 262 smaller than the part 71 to be detected. The part 71 to be detected is fixed to one end of the rotary shaft 44, through the open part 262, and the detection part 72 is set opposite to the part 71 to be detected, wherein the cover member 250 and the detection part 72 form a labyrinth structure. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicular rotating electrical machine such as a vehicular AC generator or a generator motor mounted on a passenger car, a truck, or the like.

  2. Description of the Related Art Conventionally, there is known a vehicular rotating electrical machine in which a periphery of a slip ring is covered with a covering member and a position detection device fixed to one end of a rotating shaft is disposed outside the covering member through an opening provided in the covering member. (For example, refer to Patent Document 1). This position detection device is sensitive to the magnet holder fixed to the penetrating part of the rotating shaft, the magnet held by the magnet holder, and the magnetic flux emitted from the magnet so as to be close to the facing member and face the covering member. And a magnetically sensitive element that outputs a signal corresponding thereto, and a labyrinth structure is formed between the covering member and the magnet holder.

  In addition, the stator, a rotor fixed to a rotating shaft that rotates coaxially with the stator, a bracket that supports and fixes the stator and rotatably supports the rotating shaft, and one end of the rotating shaft is disposed on the rotor. There is known a rotating electrical machine that includes a rotation position detection unit that detects a rotation position and covers the outer periphery of the rotation position detection unit with a shield member (see, for example, Patent Document 2).

In addition, a brush holder that houses a brush that is in sliding contact with a slip ring provided on the rotating shaft of the rotor, and a cover member that covers the slip ring, an opening formed by a gap formed in at least one of the brush holder and the cover member 2. Description of the Related Art An automotive alternator is known that is directed toward a brush holder as viewed from a slip ring (see, for example, Patent Document 3).
JP 2007-97236 A (page 4-10, FIG. 1-3) JP 2007-60734 A (page 3-6, FIG. 1-7) Japanese Patent Laying-Open No. 2006-6000 (page 4-8, FIG. 1-16)

  By the way, the structure disclosed in Patent Document 1 is for suppressing scattering of brush powder to the outside during rotation by forming a labyrinth structure with a covering member and a magnet holder fixed to a rotating shaft. For this reason, there has been a problem that water around the brush and slip ring cannot be sufficiently prevented and it is difficult to ensure water resistance.

  Further, in the structure disclosed in Patent Document 2, since the periphery of the rotational position detection unit is blocked from the outside by the shield member, the cooling performance of the slip position and the brush disposed in the rotational position detection unit and the vicinity thereof deteriorates. There was a problem.

  Further, in the structure disclosed in Patent Document 2, since the rear side of the rotation shaft is covered with a cover member, a space for mounting the rotation position detection unit as shown in Patent Document 2 cannot be secured on the rotation shaft. In addition, it is conceivable to open the cover member in order to attach the rotational position detector, but the cover member was originally provided to prevent water from entering the peripheral space of the slip ring. If the water resistance deteriorates with the opening of the member, the original purpose of the cover member cannot be achieved. Further, when the cover member is opened, in order to prevent the rotation position detection unit from interfering with the cover member, the diameter of the opening of the cover member needs to be larger than the diameter of the rotation position detection unit. If the diameter of the opening is made small in order to ensure the performance, the diameter of the rotational position detector is also reduced, and there is a problem that the position detection accuracy in the high-speed rotational region is lowered.

  The present invention has been created in view of the above points, and an object of the present invention is to improve the detection accuracy when detecting the position of the rotor, and to improve the cooling performance and water resistance around the slip ring. An object of the present invention is to provide a rotating electrical machine for a vehicle that can ensure the performance.

  In order to solve the above-described problems, a rotating electrical machine for a vehicle according to the present invention includes a rotor including a rotating shaft having a pair of slip rings electrically connected to a field winding, and a pair of sliding contacts with the slip rings. A brush device having a brush, a brush holder in which a housing portion for housing the pair of brushes is formed, and a cover member that covers the slip ring together with the brush holder; a rotational position detected portion disposed at one end of the rotation shaft; A rotation position detection unit that detects a rotation position of the position detection unit, and the cover member has an opening portion that is smaller than the rotation position detection unit at a position corresponding to one end of the rotation shaft. The detection unit is fixed to one end of the rotation shaft through the open part, the rotation position detection unit is arranged to face the rotation position detected unit, and the cover member and the rotation position detection unit form a maze structure.

  Since the cooling air can be introduced around the slip ring through the open portion, the cooling performance around the slip ring can be ensured. In addition, since the maze structure is formed by the non-rotating portion, it is possible to always ensure stable water resistance regardless of the rotational speed. In addition, the shape of the rotational position detected portion can be simplified, and the required seismic strength of the rotational position detected portion can be reduced. In addition, since the opening portion is covered with a larger rotational position detection unit, water does not easily enter through the opening portion, and water resistance can be ensured. Furthermore, since the rotational position detector with a large outer diameter can be used regardless of the size of the open part, the amount of movement of the outer diameter part of the rotational position detector is increased to increase the rotational speed (during high rotation). The position detection accuracy can be improved.

  Moreover, it is desirable that the rotational position detected portion described above is attached to one end of the rotational shaft after the brush device is assembled. Thereby, attachment of a rotation position detected part larger than an open part becomes easy.

  Further, it is desirable that the cover member and the rotational position detected portion described above form a maze structure (labyrinth structure) in a direction along the axial direction of the rotation shaft. Alternatively, it is desirable that the cover member and the rotational position detected portion described above form a maze structure in a direction along the radial direction of the rotation shaft. Thus, while introducing the cooling air through the gap between the cover member and the rotational position detected part, it is possible to further prevent water from entering through this gap and further ensure water resistance.

  In addition, it is desirable that the contact surfaces of the rotational position detection unit and the rotation shaft described above are formed of metals having the same or similar ionization tendency. As a result, it is possible to prevent a potential from being generated between the rotating shaft and the rotational position detected portion and corrode these contact surfaces, thereby improving the corrosion resistance.

  Moreover, it is desirable that the rotational position detected portion and the rotational shaft described above are formed of a metal having high thermal conductivity. Alternatively, it is desirable that the rotational position detected portion and the rotational shaft described above are formed of metal. Thereby, the heat of the rotor can be transmitted to the rotational position detected portion side through the rotating shaft, and the cooling performance of the rotor can be improved.

  Moreover, it is desirable that the rotational position detected portion described above is formed of a member having low thermal conductivity. Alternatively, it is desirable that the rotational position detected portion is formed of a member having lower thermal conductivity than the rotational shaft. Thereby, it is possible to prevent the rotational position detection accuracy from being deteriorated due to deformation of the rotational position detected portion due to heat.

  Hereinafter, an automotive alternator according to an embodiment to which a rotating electrical machine for a vehicle of the present invention is applied will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating an overall configuration of a vehicle AC generator according to an embodiment. 1 includes a front frame 1, a rear frame 2, a stator 3, a rotor 4, a control device 5, a brush device 6, a rotation position sensor 7, a rear cover 8, a pulley 9, and the like. It is configured to include.

  Both the front side frame 1 and the rear side frame 2 have a bowl shape, and are fixed to each other by a plurality of bolts in a state in which the openings 3 face each other and the stator 3 is sandwiched therebetween. A cylindrical bearing box 11 is formed integrally with the front frame 1, and an iron bearing box 21 is attached to the rear frame 2. The stator 3 includes a stator core 31 and a stator winding 32.

  The rotor 4 includes a field winding 41, pole cores 42 and 43, a rotating shaft 44, and the like, and is rotatably held by a pair of bearings 13 and 14 housed in bearing boxes 11 and 21. Cooling fans 45 and 46 are attached to the axial end surfaces of the pole cores 42 and 43. A pulley 9 is coupled to the front end of the rotating shaft 44 by a nut 10 and is rotated by a vehicle engine (not shown). Further, a pair of slip rings 47 and 48 connected to both ends of the field winding 41 are provided at the rear end of the rotating shaft 44 positioned outside the rear frame 2.

  The rotational position sensor 7 detects the rotational position of the rotor 4, is arranged at one end of the rotating shaft 44 and rotates with the rotor 4 as a disk-shaped detected part (rotational position detected part) 71, A detection unit (rotation position detection unit) 72 that detects the rotation position of the detected unit 71 is included. The detected portion 71 is, for example, screw-fixed to one end of the rotating shaft 44 (end portion on the slip rings 47 and 48 side). The detection unit 72 is fixed to a part of the control device 5 and is disposed to face the detected unit 71, and detects the position in the rotation direction of the region near the outer periphery of the disc-shaped detected unit 71. . Various methods can be considered as specific detection methods. For example, a magnetic body is arranged in the vicinity of the outer periphery of the detected part 71, and the rotational position of the magnetic body is detected by a detection coil provided in the detecting part 72, or a magnet is arranged in the vicinity of the outer periphery of the detected part 71, The case where the rotation position of this magnet is detected with the Hall element provided in the detection part 72 etc. can be considered. In the present embodiment, a method other than the above, for example, an optical detection method such as an optical sensor, may be used as long as the detection accuracy of the rotational position improves as the outer diameter of the detected portion 71 increases. It may be used.

  So-called electrical components such as the control device 5 and the brush device 6 are fixed to the outer axial end surface of the rear frame 2 by fixing means such as bolts. The control device 5 rectifies the three-phase AC voltage that is the output voltage of the stator winding 32 and converts it into a DC output voltage, and controls the direction and magnitude of the energization of the excitation current flowing in the field winding 41. By doing so, the output voltage of the vehicle alternator 100 is controlled. The brush device 6 is for passing an exciting current from the control device 5 to the field winding 41 of the rotor 4 and presses against each of the slip rings 47 and 48 formed on the rotating shaft 44 of the rotor 4. Brushes 61 and 62 are provided. These electrical components are covered with a rear cover 8.

  FIG. 2 is a view of the vehicle alternator 100 as viewed from the rear side, and shows a state in which the brush device 6 is exposed with the rear cover 8, the control device 5, and the rotational position sensor 7 removed. The stator winding 32 includes two sets of three-phase windings 32A and 32B, each phase coil X, Y, Z of one three-phase winding 32A and each phase coil U of the other three-phase winding 32B, Each end of V and W extends to the rear side through a through hole provided in the rear frame 2. These end portions are connected to the control device 5.

  Next, the detailed structure of the brush apparatus 6 and the to-be-detected part 71 is demonstrated. FIG. 3 is a cross-sectional view of the brush device 6. The brush device 6 includes a brush holder 200, brushes 61 and 62, and a cover member 250.

  The brush holder 200 has a box shape, and has a rectangular parallelepiped-shaped storage portions 211 and 212 that store two brushes 61 and 62 on the positive electrode side and negative electrode side, and flexible brushes 61 and 62, respectively. A pair of terminals 221 and 222 that are electrically connected to a pigtail 63 serving as a lead portion having a characteristic and project outside are provided. The terminals 221 and 222 are insert-molded in a brush holder 200 made of insulating resin.

  Further, the cover member 250 is disposed on the radially outer side with respect to the slip rings 47 and 48 and on one end (end portion on the slip ring 47 or 48 side) of the rotating shaft 44, and together with the brush holder 200, the slip ring 47, 48 is covered. Further, the cover member 250 has an opening portion 262 as an opening portion having a diameter smaller than the outermost diameter portion of the detected portion 71 at a position corresponding to one end of the rotation shaft 44.

  The brushes 61 and 62 are metal graphite containing copper powder in natural graphite and using a phenol resin or the like as a binder. For example, it is manufactured by the manufacturing process shown in FIG. That is, powder processing (step 100) for mixing raw material (natural graphite) and binder (phenol resin), mixing of copper powder (step 101), arrangement of pigtail 63 (step 102), molding (step 103), firing The brushes 61 and 62 are manufactured through each step (Step 104). The brushes 61 and 62 have the same shape, and the same shape is disposed with the pigtails 63 facing each other, and is housed in the housing portions 211 and 212 with the spring 64 interposed. The brushes 61 and 62 are pressed toward the slip rings 47 and 48 by the spring 64 and are in sliding contact within the storage portions 211 and 212.

  5 is a cross-sectional view taken along line VV in FIG. For example, as shown in FIGS. 3 and 5, the detected portion 71 includes a permanent magnet 71a having an NS magnetic pole magnetized in one direction along the surface and a holder 71b for holding the permanent magnet 71a. The detection unit 72 includes two Hall elements 72a and 72b arranged at positions near the outer periphery of the permanent magnet 71a and separated from each other by 90 °. Based on the outputs of these two Hall elements 72a and 72b, the rotational position of the permanent magnet 71a, that is, the rotational position of the rotor 4 to which the permanent magnet 71a is fixed via the holder 71b can be detected.

  Further, as shown in FIG. 5, the detection unit 72 and the cover member 250 form a maze structure for preventing intrusion of water and other foreign matters from the top direction indicated by the arrow A. The intrusion direction of water and other foreign matters is indicated by an arrow B. On the other hand, since air (arrow C) has a smaller mass than water and other foreign substances, it passes through the maze structure formed by the detection unit 72 and the cover member 250 and reaches the vicinity of the detection unit 71, and the opening 262. To the vicinity of the slip rings 47, 48. Even if water or other foreign matter reaches the vicinity of the detected portion 71 through the maze structure, it is discharged in the ground direction through a gap between the detecting portions 72 provided in the ground direction opposite to the arrow A ( Arrow D).

  The detected portion 71 of the rotational position sensor 7 described above is attached and fixed to one end of the rotating shaft 44 after the brush device 6 is assembled, that is, with the periphery of the slip rings 47 and 48 covered with the cover member 250. . Thereby, attachment of the to-be-detected part 71 larger than the open part 262 becomes easy.

  In the present embodiment, the cover member 250 and the detection unit 72 form a maze structure in a direction along the radial direction of the rotation shaft 44. Specifically, as shown in FIG. 3, a labyrinth structure along the radial direction is formed by partially overlapping the axial positions of the cover member 250 and the detection unit 72. In the structure shown in FIG. 3, the axial position and the radial position of each of the detected portion 71 and the cover member 250 are partially overlapped to form a maze structure along the radial direction and the axial direction between them. Is formed. Thus, while introducing the cooling air through the gap between the cover member 250 and the detection unit 72 (not shown in FIG. 1, the rear cover 8 is provided with a through hole for introducing cooling air, and through this through hole. Cooling air is introduced from the outside to the inside of the rear cover 8 and a part thereof is guided to the gap between the cover member 250 and the detection unit 72), and water penetration is suppressed from the outside through this gap to ensure water resistance. be able to.

  Further, the contact surfaces of the detected portion 71 and the rotating shaft 44 are formed of metals having the same or similar ionization tendency. As a result, it is possible to prevent a potential from being generated between the rotating shaft 44 and the detected portion 71 and to corrode these contact surfaces, thereby improving the corrosion resistance.

  The detected portion 71 and the rotating shaft 44 are made of metal (more preferably, metal having high thermal conductivity). Thereby, the heat of the rotor 4 can be transmitted to the detected portion 71 side through the rotating shaft 44, and the cooling performance of the rotor 4 can be improved. In addition, from the viewpoint of improving the cooling performance, it is desirable that the detected portion 71 is made of a metal having high thermal conductivity. The detected portion 71 may be formed of a member having low thermal conductivity, or the detected portion 71 may be formed of a member having lower thermal conductivity than the rotating shaft 44. That is, the material of the detected portion 71 may be determined depending on which of the cooling performance and the rotational position detection accuracy is prioritized.

  As described above, in the vehicle alternator 100 of the present embodiment, the cooling air can be introduced around the slip rings 47 and 48 through the opening 262, so that the cooling performance around the slip rings 47 and 48 is ensured. Can do. Moreover, since the open part 262 is covered with the detected part 71 larger than this, it becomes difficult for water to enter through the open part 262, and water resistance can be ensured. Furthermore, since the detected portion 71 having a large outer diameter can be used regardless of the size of the open portion 262, the amount of movement during rotation of the outer diameter portion (region near the outer periphery) of the detected portion 71 is increased. It is possible to improve the position detection accuracy in the high-speed rotation range (during high rotation).

  Needless to say, the present invention is also applied to a generator motor that drives a rotor by generating a rotating magnetic field in the stator.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. 6 to 9 are diagrams showing modifications of the brush device 6 and the rotational position sensor 7. In these drawings, the schematic shapes of the detected portion 71, the detecting portion 72, and the cover member 250 are shown, and the Hall element and the like are omitted.

  6A shows a state in which the detected portion 71 is exposed from the brush device 6, and FIG. 6B shows a cross-sectional structure including the brush device 6 and the rotational position sensor 7. In the examples shown in these drawings, the maze structure formed by the detection unit 72 and the cover member 250 is arranged mainly in the top direction indicated by the arrow A. This point is also the same for the modified example shown in FIGS.

  8A shows a state in which the detected portion 71 is exposed from the brush device 6, FIG. 7B shows a cross-sectional structure including the brush device 6 and the rotational position sensor 7, and FIG. 7 (B) is a cross-sectional view taken along line VIII-VIII. Each arrow included in FIG. 7C corresponds to each arrow included in FIG. 5 (arrow A is the celestial direction, arrow B is the entry direction of water and other foreign matters, arrow C is the air flow, Arrow D or the flow of discharged foreign matter).

  FIG. 9A shows a state in which the detected portion 71 is exposed from the brush device 6, and FIG. 9B shows a cross-sectional structure including the brush device 6 and the rotational position sensor 7. In the examples shown in these drawings, the surface of the cover member 250 near the opening 262 is inclined with respect to the rotation shaft 44. Thereby, while simplifying the structure of the cover member 250, the maze structure can be formed and the gap of the opening 262 can be reduced.

It is a figure showing the whole composition of the alternator for vehicles of one embodiment. It is the figure which looked at the alternating current generator for vehicles from the rear side. It is sectional drawing of a brush apparatus. It is a figure which shows the manufacturing process of a brush. It is the VV sectional view taken on the line of FIG. It is a figure which shows the modification of the wall part integrally formed with the brush holder. It is a figure which shows the modification of the wall part integrally formed with the brush holder. It is a figure which shows the modification of the wall part integrally formed with the brush holder. It is a figure which shows the modification of the wall part integrally formed with the brush holder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front side frame 2 Rear side frame 3 Stator 4 Rotor 5 Control apparatus 6 Brush apparatus 7 Rotation position sensor 8 Rear cover 9 Pulley 44 Rotating shaft 47, 48 Slip ring 61, 62 Brush 63 Pigtail 64 Spring 71 Detected part 72 Detection Part 100 AC generator for vehicle 200 Brush holder 211, 212 Storage part 221, 222 Terminal 250 Cover member 262 Opening part

Claims (9)

A brush holder in which a rotor including a rotating shaft having a pair of slip rings electrically connected to a field winding, a pair of brushes slidably contacting the slip rings, and a storage portion for storing the pair of brushes are formed And a brush device having a cover member that covers the slip ring together with the brush holder, a rotational position detected portion disposed at one end of the rotational shaft, and a rotational position detection that detects a rotational position of the rotational position detected portion A rotating electrical machine for a vehicle comprising:
The cover member has an opening portion smaller than the rotation position detected portion at a position corresponding to one end of the rotation shaft,
The rotational position detected part is fixed to one end of the rotating shaft through the opening part,
The rotational position detection unit is disposed to face the rotational position detected unit,
The rotating electrical machine for a vehicle according to claim 1, wherein the cover member and the rotational position detector form a maze structure. In claim 1,
The rotating position detected part is attached to one end of the rotating shaft after assembling the brush device. In claim 1 or 2,
The vehicular rotating electrical machine according to claim 1, wherein the cover member and the rotational position detected portion form a maze structure in a direction along an axial direction of the rotation shaft. In any one of Claims 1-3,
The vehicular rotating electrical machine according to claim 1, wherein the cover member and the rotational position detected portion form a maze structure in a direction along a radial direction of the rotation shaft. In any one of Claims 1-4,
The rotating electrical machine for a vehicle according to claim 1, wherein the contact surfaces of the rotational position detected portion and the rotational shaft are made of metals having the same or similar ionization tendency. In any one of Claims 1-5,
The rotating electrical machine for a vehicle according to claim 1, wherein the rotational position detected portion and the rotating shaft are made of a metal having high thermal conductivity. In any one of Claims 1-5,
The rotating electrical machine for vehicles, wherein the rotational position detected portion and the rotational shaft are made of metal. In any one of Claims 1-5,
The rotating electrical machine for a vehicle according to claim 1, wherein the rotational position detected portion is formed of a member having low thermal conductivity. In any one of Claims 1-5,
The rotating electrical machine for a vehicle according to claim 1, wherein the rotational position detected portion is formed of a member having lower thermal conductivity than the rotational shaft.

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