Abstract:
A rotating electric machine including: a bracket holding a rotor and a stator of a motor; a heat sink provided fixedly to the bracket on an outside of the bracket; a resolver disposed between the heat sink and the motor; a stator circuit portion and a field circuit portion disposed to the heat sink on a side opposite to the resolver; and a control board supported on an insert case attached to the heat sink and electrically connected to the stator circuit portion and the field circuit portion. A resolver input-output terminal is electrically connected to the control board by passing through an insertion hole provided to the heat sink. The rotating electric machine configured in this manner is compact and inexpensive with an excellent heat-releasing performance and a capability of reducing man-hours required for assembly and components required for connection.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a rotating electric machine, and more particularly, to a rotating electric machine with a built-in controller. 
         [0003]    2. Background Art 
         [0004]    For a rotating electric machine, for example, a rotating electric machine with a built-in controller employed for vehicle control, various ideas have been put into practice to connect a control board of a motor to a resolver as a rotation angle sensor of a rotation shaft of the motor, so that components required for connection and man-hours required for assembly can be reduced. Patent Document 1 proposes a technique as follows. That is, a resolver stator is fixed to a lead frame of a controller while a resolver input-output terminal opposes the control board. Then, one end of the resolver input-output terminal is inserted axially into a through-hole provided to a wiring pattern on the control board and soldered therein. Consequently, the resolver is electrically connected to the control board. 
       CITED LIST 
     Patent Document 
       [0005]    Patent Document 1: Japanese Patent No. 4479821 
         [0006]    In the rotating electric machine with a built-in controller disclosed in Patent Document 1, however, a heat-releasing means is not provided to any of the control board, a stator circuit portion, and a field circuit portion. Hence, a cooling performance is not satisfactory. 
       SUMMARY OF THE INVENTION 
       [0007]    The invention therefore has an object to provide a compact and inexpensive rotating electric machine capable of enhancing a heat-releasing performance, making an assembling work of a resolver easier, and reducing components and man-hours required for connection by providing a heat sink to a rotating electric machine including a control board of a motor, a stator circuit portion, a field circuit portion, and a resolver. 
         [0008]    A rotating electric machine according to an aspect of the invention includes: a bracket holding a rotor and a stator of a motor; a heat sink provided fixedly to the bracket on an outside of the bracket; a resolver formed of a resolver rotor disposed to a rotation shaft of the motor between the heat sink and the motor and a resolver stator surrounding the resolver rotor; a stator circuit portion and a field circuit portion disposed to the heat sink on a surface opposite to the resolver; and a control board attached to an insert case held by the heat sink on a side of the heat sink opposite to the resolver and electrically connected to the stator circuit portion and the field circuit portion. A resolver input-output terminal is electrically connected to the control board by passing through an insertion hole provided to the heat sink. 
         [0009]    According to the configuration above, it becomes possible to provide a compact and inexpensive rotating electric machine having an excellent heat-releasing effect on a stator circuit portion, a field circuit portion, and a control board of the rotating electric machine, making an assembling work of a resolver easier in the course of assembly of the rotating electric machine, and capable of reducing man-hours required to connect components and the number of components. 
         [0010]    The foregoing and other objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a sectional side view of a rotating electric machine according to a first embodiment of the invention; 
           [0012]      FIG. 2  is a front view of the rotating electric machine of  FIG. 1  in a state where a resin cover is removed; 
           [0013]      FIG. 3  is a cross section taken on the line A-A′ of  FIG. 2 ; 
           [0014]      FIG. 4  is a front view of a heat sink when viewed from heat-releasing fins side; 
           [0015]      FIG. 5  is a front view of a resolver stator of a rotating electric machine according to a second embodiment of the invention; 
           [0016]      FIG. 6  is a sectional side view of the rotating electric machine according to the second embodiment of the invention; 
           [0017]      FIG. 7  is a front view showing a state where a resolver stator is attached to a heat sink; 
           [0018]      FIG. 8  is a cross section corresponding to the cross section taken on the line A-A′ of  FIG. 2  and showing a rotating electric machine according to a third embodiment of the invention; 
           [0019]      FIG. 9  is a cross section corresponding to the cross section taken on the line A-A′ of  FIG. 2  and showing a rotating electric machine according to a fourth embodiment of the invention; and 
           [0020]      FIG. 10  is a partially enlarged view of  FIG. 9 . 
       
    
    
     DETAILED DESCRIPTION 
     First Embodiment 
       [0021]      FIG. 1  is a cross section of a rotating electric machine with a built-in controller (hereinafter, referred to simply as the rotating electric machine) according to a first embodiment of the invention.  FIG. 2  is a front view of the rotating electric machine from which a resin cover  18  is removed.  FIG. 3  is a cross section taken on the line A-A′ of  FIG. 2 . 
         [0022]    Referring to  FIGS. 1 through 3 , the rotating electric machine includes a rotor  2  having a field winding  2   a  of a motor wound thereon and attached to a rotation shaft  9 , a stator  3  having a three-phase stator winding  3   a  wound thereon, a front bracket  4  and a rear bracket  5  holding the rotor  2  and the stator  3 , the rotation shaft  9  both ends of which are supported in a rotatable manner on the front bracket  4  and the rear bracket  5  via bearings  7  and  8 , respectively, a pulley  10  fixed to a front end of the rotation shaft  9 , a resolver  6  disposed at a rear end of the rotation shaft  9  and described below, a heat sink  13 , and a resin cover  18  covering a control board  16  and the like. 
         [0023]    A slip ring  11  is fit to the rear end of the rotation shaft  9  and a brush  12  coming in sliding contact with the slip ring  11  is held by a brush holder  12   a . A current is supplied to the field winding  2   a  through the slip ring  11  and the brush  12 . 
         [0024]    A resolver stator  6   b  of the resolver  6  serving as a rotation angle sensor is disposed in a cylindrical sensor fixing portion  5   a  formed at a center of the rear bracket  5  to face outward. A resolver rotor  6   a  is fixed to the rotation shaft  9  in such a manner so as to oppose the resolver stator  6   b . The resolver  6  is a rotation angle sensor disposed coaxially with the rotation shaft  9  and detecting a magnetic pole position of the rotation shaft  9 , that is, the rotor  2 . 
         [0025]    The heat sink  13  is disposed on the outside of the rear bracket  5  and on a side of the resolver  6  opposite to the motor. The heat sink  13  is formed of a plate-like portion made of highly heat conductive metal and a large number of heat-releasing fins  13   a  implanted in a surface of the plate-like portion on a side of the rear bracket  5 . The heat-releasing fins  13   a  are fixed to the rear bracket  5 . As is shown in  FIG. 4 , the heat sink  13  is provided with an opening of a size large enough for the slip ring  11  and the brush ring  12   a  at a center. Also, the heat sink  13  is provided with an insertion hole  13   b  through which a resolver input-output terminal described below is inserted. 
         [0026]    On a side of the heat sink  13  opposite to the motor, an insert case  19  is attached to the heat sink  13  and the control board  16  disposed oppositely to the heat sink  13  is attached to the insert case  19 . A stator circuit portion  14  and a field circuit portion  15  are fixed onto the heat sink  13  opposing the control board  16 , so that heat generated in each circuit portion is released by the heat sink  13 . 
         [0027]    Control of the motor and a detection of the magnetic pole position of the rotor  2  by the resolver  6  are all performed by the control board  16 . Hence, a connection terminal of the stator circuit portion  14 , a connection terminal of the field circuit portion  15 , and a resolver input-output terminal  6   c  pulled out from the resolver stator  6   b  are all led to the control board  16  and soldered to through-holes provided to a wiring pattern on the circuit board  16 . Because the stator circuit portion  14  and the field circuit portion  15  face the control board  16 , the connection terminal of each circuit portion can be connected directly to the control board  16 . However, because there is the heat sink  13  between the resolver  6  and the control board  16 , the resolver input-output terminal  6   c  is inserted through the insertion hole  13   b  provided to the heat sink  13  and soldered to a through-hole provided to the wiring pattern on the control board  16 . The insertion hole  13   b  is, for example, of a rectangular shape of a size large enough for the resolver input-output terminal  6   c  to be inserted. 
         [0028]    The control board  16  can be connected to each of the stator circuit portion  14 , the field circuit portion  15 , and the resolver input-output terminal  6   c  at a time by inserting the respective terminals into the corresponding through-holes provided to the wiring pattern on the control board  16  and then soldering all the terminals to the through-holes simultaneously. Because the resolver input-output terminal  6   c  can come in close proximity to the control board  16  bypassing through the insertion hole  13   b , it is also possible to connect the resolver input-output terminal  6   c  to the control board  16  without requiring any extra component, such as a connector. 
         [0029]    According to the configuration of the first embodiment as described above, by providing the heat sink  13 , heat of the stator circuit portion  14  and the field circuit portion  15  is released directly to the heat sink  13  and heat of the control board  16  is released from the heat sink  13  through the connection terminal and the insert case  19 . It thus becomes possible to achieve a satisfactory cooling effect on the control board  16 , the stator circuit portion  14 , and the field circuit portion  15 . Meanwhile, the connection structure as described above makes a resolver connection feasible without having to interpose a component, such as a connector. It thus becomes possible to reduce the cost and the size. In addition, the resolver input-output terminal  6   c  can be soldered to the control board  16  at the same time when the stator circuit portion  14  and the field circuit portion  15  are soldered to the control board  16 . Accordingly, workability is enhanced and man-hours required for assembly and the number of components can be reduced. 
       Second Embodiment 
       [0030]      FIGS. 5 through 7  are views used to describe a second embodiment of the invention.  FIG. 5  is a sectional side view of a rotating electric machine of the second embodiment.  FIG. 6  is a front view of a resolver stator of this rotating electric machine.  FIG. 7  is a front view of the resolver stator when attached to a heat sink. 
         [0031]    A resolver stator  6   b  of the second embodiment is provided with a holding member  6   d  made of an insulator that surrounds and holds the resolver stator  6   b . Projected portions  6   g  are provided at three points on a periphery of the holding member  6   d  and an attachment hole  6   e  is provided to each projected portion  6   g . On the other hand, a heat sink  13  is provided with screw holes  13   c  (see  FIG. 4 ) corresponding to the respective attachment holes  6   e.    
         [0032]    The resolver stator  6   b  is fixed to the heat sink  13  with screws  23  using the attachment holes  6   e  of the holding member  6   d  so as to come into close contact with the heat sink  13  on a side where the heat-releasing fins  13   a  are provided. The resolver input-output terminal  6   c  is introduced from the heat-releasing fins side of the heat sink  13  to come out to the opposite side by passing through the insertion hole  13   b  and soldered to the through-holes of the wiring pattern on the control board  16 . The rest of the configuration other than the attachment structure of the resolver stator  6   b  is the same as that of the first embodiment above. 
         [0033]    It should be appreciated that the resolver stator  6   b  is not necessarily fixed to the heat sink  13  by screwing. For example, other fixing methods, such as bonding and thermal caulking, are also available as long as a functionally required fixing force is obtained. In the case of screwing, the attachment holes are provided at three points herein. It should be appreciated, however, that the number of the attachment holes is not particularly limited to three. 
         [0034]    According to the rotating electric machine of the second embodiment, by preliminarily fixing the resolver stator  6   b  to the heat sink  13  before the rotating electric machine as a whole is assembled, it becomes possible to handle the resolver stator  6   b , the heat sink  13 , and the control board  16  as a single integral piece. Consequently, an assembling work of the resolver and the like becomes easier. Also, an electrical connection work by soldering the resolver input-output terminal  6   c  to the control board  16  is allowed before the single integral piece is attached to a motor portion. Further, because the resolver stator  6   b  is fixed to the heat sink  13 , a cooling effect on the resolver  6  is enhanced. The other effects are the same as those obtained in the first embodiment above. 
       Third Embodiment 
       [0035]      FIG. 8  is a cross section showing a vicinity of a resolver of a rotating electric machine according to a third embodiment of the invention. In the third embodiment, a resolver input-output terminal holding portion  6   f , which is a portion of the resolver input-output terminal  6   c  heading toward the control board  16 , that is a portion coming out from the holding member  6   d  and going into the insertion hole  13   b  of the heat sink  13  and inserted into an insulator, is formed integrally with the holding member  6   d  of the resolver stator  6   b , and an end of the resolver input-output terminal holding portion  6   f  is fit and fixed in the insertion hole  13   b  of the heat sink  13 . The rest of the configuration is the same as those of the first or second embodiment above. 
         [0036]    According to the third embodiment, the resolver input-output terminal  6   c  is held by the resolver input-output terminal holding portion  6   f  and the end of the resolver input-output terminal holding portion  6   f  is fixed in the insertion hole  13   b  of the heat sink  13 . Hence, breaking and bending of the terminal do not occur and electrical connection to the control board  16  is further ensured. In addition, because the resolver input-output terminal holding portion  6   f  is formed integrally with the holding member  6   d , it becomes possible to form the resolver input-output terminal holding portion  6   f  without increasing the number of components. The other effects are the same as those obtained in the first embodiment above. 
       Fourth Embodiment 
       [0037]      FIG. 9  is a cross section showing a vicinity of a resolver of a rotating electric machine according to a fourth embodiment of the invention.  FIG. 10  is an enlarged view of a periphery of an insertion hole of a heat sink of  FIG. 9 . 
         [0038]    According to a rotating electric machine of the fourth embodiment, as is shown in  FIG. 9 , the control board  16  is inserted into the insert case  19  by a potting member  20 , such as epoxy resin, and fixed therein. When the insert case  19  is filled with the potting member  20 , a high sealing performance is required. To this end, in the fourth embodiment, a cylindrical wall  13   d  is provided to the insertion hole  13   b  of the heat sink  13  on a side of the control board  16 . An inner side of the cylindrical wall  13   d  is used as a sealing member reservoir portion  22  to store the sealing member  21 , such as highly viscous silicon resin, between the insertion hole  13   b  and the resolver input-output terminal holding portion  6   f . It goes without saying that a clearance between the insertion hole  13   b  and the resolver input-output terminal holding portion  6   f  can merely be sealed by the sealing member  21  without providing the reservoir portion  22 . 
         [0039]    Owing to the configuration as above, it becomes possible to secure a high sealing performance at the time of potting of the control board  16  by ensuring air tightness between the insertion hole  13   b  of the heat sink  13  and the resolver input-output terminal holding portion  6   f . By potting the control board  16 , not only can the control board  16  be protected from dust and moisture, but also vibration resistance and a heat-releasing performance can be enhanced at the same time. It should be appreciated that the potting member  20  to be used is not particularly limited to epoxy resin and the sealing member  21  is not particularly limited to silicon resin, either. The other effects are the same as those in the first embodiment above. 
         [0040]    While the invention has been described by way of the first through fourth embodiments above, various modifications and alterations of this invention will be apparent to those skilled in the art without departing from the scope and spirit of this invention, and it should be understood that this is not limited to the illustrative embodiments set forth herein.