JP4848225B2 - Axial gap motor - Google Patents

Description

  The present invention relates to an axial gap type electric motor, and more particularly to an axial gap type electric motor provided with an eccentricity allowing structure for a rotating shaft.

2. Description of the Related Art Conventionally, as an electric motor corresponding to an electric motor that requires low speed and high torque, there is an axial gap type electric motor in which a stator and a rotor are arranged to face each other in the direction of a rotation axis. A conventional axial gap type electric motor includes a stator around which a coil is wound, a rotor that is arranged to face the coil in the direction of the rotation axis, and a plurality of pairs of permanent magnets are arranged in a circumferential magnetomotive force type. And a rotating magnetic field is generated by passing a current through the stator coil, and the rotor is rotated by a magnetic attraction force and a repulsive force between the stator and the rotor (Patent Literature). 1 and 2).
JP 2002-153028 A Japanese Patent Laid-Open No. 11-187635

  However, in these conventional axial gap motors, the center line of the stator and the rotation center line of the rotor are configured as the same center line. For example, the rotation center line of the rotating member connected to the rotor is also the rotor center line. Although it is necessary to make it the same as the rotation center line, the variation cannot be removed in consideration of the assembly accuracy, etc. In order to allow a deviation (eccentricity) in the orthogonal direction to this center line, for example, Oldham coupling Is installed between the rotor and the rotated member.

  For this reason, the subject of a cost increase and a weight increase arises with the setting of Oldham coupling.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide an axial gap type electric motor having an eccentricity allowing structure.

  The present invention relates to a rotor in which a plurality of permanent magnets or coils are arranged at predetermined intervals in the circumferential direction, and the permanent magnet or coil so as to face one of the permanent magnets or coils in the center line direction of the rotor. An axial gap type electric motor having an electric motor portion disposed so as to face the rotor with a predetermined gap in the direction of the center line of the rotor. The rotor and the stator are internally provided, and the rotor is allowed to slide between the case for fixing the stator and the case and the rotor in a direction orthogonal to the center line of the case. And a bearing that enables rotation around the center line of the rotor, a ring member provided on one outer peripheral side of the permanent magnet or the coil installed on the rotor, In a direction orthogonal to the center line of the rotor, between a support member installed to be rotatable relative to the ring member around the rotor center line on the circumferential side, and the case inner surface and the support member An axial gap type electric motor comprising: an urging unit that generates an urging force and urges a center line of the rotor and a center line of the stator to be the same center line. .

  In the present invention, an urging force is generated between the case and the support member connected to the rotor in a direction perpendicular to the rotation axis of the rotor, so that the rotation center line of the rotor and the center line of the stator are the same center line. Therefore, even when an external force is applied to the rotor, it is possible to suppress the deviation in the direction perpendicular to the rotation axis of the rotor between the rotation center line of the rotor and the center line of the stator. it can. For this reason, it is not necessary to set an Oldham coupling that has been conventionally provided to allow this deviation, and cost reduction and weight reduction can be achieved.

  Further, since it becomes unnecessary to position the rotated member from the outside and the rotated member can be held by the electric motor, the structure can be simplified.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing a configuration of an axial gap type electric motor 1 of the present invention, in which a rotation center line of a rotor shaft 2 (hereinafter referred to as a center line X1) is eccentric with respect to a center line of a case 5. Indicates.

  In the present embodiment, the rotor shaft 2 that rotates the member to be rotated, the rotor 3 that is fixed to the rotor shaft 2, and the rotor shaft 2 are provided so as to face the rotor 3 with a predetermined gap in the direction of the center line X1. A plurality of electric motor parts 1 a composed of a pair of stators 4 are arranged in the axial direction of the rotor and housed in the case 5 to constitute the axial gap type electric motor 1. In the present embodiment, the description will be given using the axial gap type electric motor 1 provided with the two rows of electric motor portions 1a. However, the present invention is not limited to this, and the axial gap formed by a plurality of or one row of electric motor portions 1a may be used. The type motor 1 may be used.

  FIG. 2 is a diagram for explaining the shape of the rotor 3. The rotor 3 includes four equal-length arm portions 6 extending in the orthogonal direction from the center line X1 of the rotor shaft 2 connected to a rotated member (not shown). These arm portions 6 are arranged at equal intervals (90 ° intervals in FIG. 2) in the circumferential direction. A cylindrical ring member 7 that connects the arm portions 6 is fixed to a distal end portion on the outer peripheral side of each arm portion 6.

  As shown in FIG. 1, a permanent magnet 12 is attached to the arm portion 6 of the rotor 3. For example, as shown in FIG. 3, the permanent magnets 12 are each formed in a substantially fan shape when viewed from the direction of the center line X <b> 1, and are held so as to sandwich the intermediate portions of the arm portions 6. The permanent magnet 12 is formed so that both end faces 12 a are parallel to a plane orthogonal to the center line X <b> 1 of the rotor shaft 2. Needless to say, the number, shape, and the like of the arm portions 6 are not limited to those in the embodiment.

  In the direction of the center line X1 of the rotor shaft 2, the stator 4 is fixed to a surface 5e orthogonal to the rotor shaft center line X1 of the case 5, which will be described later, at a pair of opposed positions to the permanent magnet 12 of the rotor 3. Is done. The stator 4 includes a yoke portion 8 fixed to the case 5, a teeth portion 9 having a substantially fan shape when viewed from the direction of the center line X <b> 2 of the stator 4, and a coil 10 wound around the teeth portion 9. Composed. The yoke portion 8 fixes the tooth portion 9 to the case 5. It plays the role of turning the magnetic flux of the tooth portion 9 in the circumferential direction to flow to another tooth portion 9. The teeth portion 9 is formed to protrude from the yoke portion 8 toward the rotor 3 in the direction of the center line X1, and its end surface is formed in parallel to the end surface 12a of the permanent magnet 12. Further, the coil 10 is insulated from the tooth portion 9 via an insulator or the like (not shown).

  A case 5 for housing each electric motor unit 1a composed of a rotor 3 and a stator 4 has a bottomed cylindrical main body 5a, a through space through which the rotor shaft 2 penetrates while closing the open end of the main body 5a. A lid 5b having 5d and a hollow disk-shaped partition plate 5c arranged so as to partition the inside of the case in a direction orthogonal to the center line X2 of the case 5 are configured. The partition plate 5c divides the inside of the case 5 into two equally-shaped spaces 5x and 5y arranged in the direction of the center line X2, and the rotor shaft 2 is inserted through the center portion thereof. The motor part 1a is configured in the space parts 5x and 5y, respectively, and the stator 4 is placed on the surface 5e of the case 5 perpendicular to the center line X2 of the case 5 forming the space parts 5x and 5y for housing the motor part 1a. The rotor 3 is fixed between the stators 4 so as to face each other in the direction of the center line X2, and the electric motor unit 1a is configured. In the state where each electric motor part 1a is disposed in the case 5, the respective gaps 14 in the direction of the center line X2 between the rotor 3 and the pair of stators 4 facing the rotor 3 are set to predetermined values. Installed.

  A cylindrical ring member 7 that connects the tips of the arm portions 6 of the rotor 3 is formed around the center line X1. The end faces 7a on both sides of the ring member 7 in the direction of the center line X1 of the rotor shaft 2 are formed so as to face the inner surface 5e of the case 5 and to be orthogonal to the center line X1. The bearings 13 are installed between the both end surfaces 7a and the surface 5e of the case 5, respectively. The bearing 13 is arranged in an annular shape, for example, and allows the rotor shaft 2 to slide in a direction perpendicular to the center line X <b> 1 with respect to the case 5. Further, the ring member 7 can rotate around the center line X1 of the rotor shaft 2 in a state where the ring member 7 is in sliding contact with the case 5. The bearing 13 may be a slide bearing or the like, but is not limited to this, and any means that allows the rotor 3 to slide with respect to the case 5 and rotate the rotor 3 may be used.

  Here, the through space 5 d through which the rotor shaft 2 of the case 5 passes is formed larger than the diameter of the rotor shaft 2 by a predetermined amount. As described above, the rotor 3 is configured to be slidable in a direction orthogonal to the center line X1, but the rotor 3 is attached to the case 5 due to the difference between the diameter of the through space 5d and the diameter of the rotor shaft 2. On the other hand, the amount of movement in the direction orthogonal to the center line X1 of the rotor shaft 2 is defined.

  On the outer peripheral side of the ring member 7, a cylindrical support member 15 having a center line X1 of the rotor shaft 2 as a center line is disposed with a predetermined gap so as to be movable. A bearing 16 is provided between the support member 15 and the ring member 7 so as to be relatively rotatable.

  Annular annular spaces 5x1, 5y1 are defined between the outer peripheral surface of the support member 15 and the inner peripheral surface of the case 5, and the annular spaces 5x1, 5y1 defined by the rotor 3 in the case 5 are rotor shafts. When the support ring 15 is displaced in a direction orthogonal to the second center line X1, the cross section thereof is configured to be deformable. Here, since the support member 15 supports the ring member 7 of the rotor 3 via the bearing 16 on the inner peripheral surface thereof, the support member 15 does not rotate even if the ring member 7 rotates, and the ring member 7 (that is, the rotor 3) is only displaced along with the displacement in the direction orthogonal to the center line X1 of the rotor shaft 2.

  FIG. 3 is a cross-sectional view showing the configuration in the annular spaces 5x1, 5y1 partitioned by the support member 15. Since the annular spaces 5x1, 5y1 have the same configuration, FIG. 3 represents the configuration of the annular space 5y1. To explain.

  As shown in FIG. 3, the annular space 5 y 1 partitioned by the support member 15 is further partitioned into four spaces 5 ya to 5 yd in the circumferential direction by a partition plate 17 provided on the outer periphery of the support member 15. These four spaces 5ya to 5yd are partitioned so that their volumes are equal when the rotation center line X1 of the rotor 3 and the center line X2 of the stator 4 are the same center line. The partition plate 17 has a base end supported by the support member 15 so as to be able to swing, and an urging means such as a torsion coil spring 18 is disposed at the swing center. For this reason, the outer end of the partition plate 17 is pressed against the inner surface 5 f parallel to the center line X <b> 2 of the case 5.

  Accordingly, the rotor 3 is supported by the torsion coil spring 18 with respect to the inner peripheral surface 5f of the case 5 via the support ring 15. For this reason, assuming that the spring characteristics of the torsion coil springs 18 are the same, when the rotor 3 is displaced in the direction orthogonal to the rotor shaft 2 with respect to the case 5, the torsion coil spring 18 causes the rotor 3 to have the case 5, That is, a biasing force that is coaxial with the stator 4 acts. Therefore, when the external force in the direction orthogonal to the center line X1 does not act on the rotor 3, the torsion coil spring 18 connects the center line X1 of the rotor 3 and the center line X2 of the stator 4 to the same center line. Hold to match.

  In the present embodiment, the permanent magnet 12 and the coil 10 are installed on the rotor 3 and the stator 4, respectively, but the coil may be installed on the rotor and the permanent magnet may be installed on the stator.

  Next, the operation will be described.

  When the coil 10 of the stator 4 is energized, the axial gap type electric motor of the present invention generates a rotating magnetic field, and accordingly, a magnetic attractive force and a repulsive force between the stator 4 and the rotor 3. Thus, the rotor 3 is rotated in a predetermined direction. By this rotation, a rotation member (not shown) connected to the rotor shaft 2 of the rotor 3 rotates.

  When the rotated member is connected to the rotor 3 via the rotor shaft 2, an external force acting on the rotated member in a direction perpendicular to the center line X 1 of the rotor shaft 2 is also applied to the rotor 3 through the rotor shaft 2. Will work. Here, as described above, the rotor 3 includes the bearing 13 that can slide in the direction orthogonal to the center line X1 of the rotor shaft 2 with respect to the stator 4 (= case 5). When the rotor shaft 2 is displaced by external force from the member to be rotated, that is, the center line X2 of the case 5 (stator 4) and the center line X1 of the rotor shaft 2 (rotor 3) are displaced in the orthogonal direction ( In the case of eccentricity), the bearing 13 allows the rotor 3 to slide in the direction perpendicular to the stator 4, and the rotor 3 rotates about a position eccentric with respect to the center line of the stator 4. can do. For this reason, when the rotor shaft 2 and the rotated member are connected coaxially, an allowable range of accuracy for matching the center lines can be set large. Therefore, it is not necessary to provide, for example, an Oldham coupling as a means for allowing eccentricity in the orthogonal direction of the rotor shaft between the rotor shaft 2 and the rotated member, thereby reducing cost and weight. it can.

  Further, the support member 15 supported so as to be relatively rotatable around the center line X1 of the rotor shaft 2 with respect to the ring member 7 of the rotor 3 defines an annular space 5x1, 5y1 between the case 5 and the support member 15 A partition plate 17 urged by a torsion coil spring 18 is interposed between the case 5 and the case 5. Therefore, when an external force that tries to decenter the center line X1 of the rotor 3 from the center line X2 of the stator 4 acts on the rotor shaft 2, the center lines X1 and X2 coincide with each other against the external force. Thus, the urging force of the torsion coil spring 18 acts so as to restore. For this reason, it becomes easy to maintain the center line X1 of the rotor 3 and the center line X2 of the stator 4 on the same axis as the external force decreases.

  Further, when an external force is not applied or when a member to be rotated is not connected, the torsion coil spring 18 is provided, so that the torsion coil spring 18 causes the center line X1 of the rotor 3 and the center line X2 of the stator 4 to Centering action is made the same, and the same center line can be obtained.

  Next, a second embodiment will be described with reference to FIGS. In the first embodiment, the rotor 3 is supported by the case 5 (= stator 4) via the biasing means 17a, so that the center line X1 of the rotor 3 and the center line X2 of the stator 4 are The same urging force is applied. On the other hand, in this embodiment, as a configuration in which the spaces 5ya to 5yd defined by the support member 15, the partition plate 17, and the case 5 are hermetically sealed, a configuration for supplying and discharging fluid into this space is added. In this embodiment, the center lines X1 and X2 of the rotor 3 and the stator 4 are always the same center line by controlling the pressure in the space.

  In addition, fluids such as air, oil, and MR fluid are supplied and discharged in the sealed spaces 5ya to 5yd, respectively, and a supply / discharge port 20 for that purpose is added. The supply / discharge port 20 may be provided in each of the spaces 5xa to 5xd and 5ya to 5yd that further divide the annular spaces 5x1 and 5y1, but as shown in FIG. 1, the motor units 1a are arranged in two rows in the axial direction. In this case, the partition plate 5c is provided with a communication port 19 that communicates with the spaces 5xa to 5xd and 5ya to 5yd that are parallel in the direction of the center line X1, and the supply / discharge port 20 is provided in one of the spaces that communicate with each other. It may be.

  In the present embodiment, a seal is provided at the edge of each partition plate 17, and the spaces 5xa to 5xd and 5ya to 5yd are sealed. A sensor for detecting the pressure in each of the spaces 5xa to 5xd, 5ya to 5yd, or a means for estimating the pressure is provided, and the detected or estimated pressure value is read by the controller 30. The controller 30 reads the center line X1 of the rotor 3 and the stator. The flow rate of fluid to be supplied to or discharged from each space is controlled so that the center line X2 of 4 is the same center line.

  FIG. 4 is a schematic diagram illustrating an example of the configuration of the hydraulic control system according to the present embodiment. First, pressure sensors 20a to 20d that respectively detect pressures in the spaces 5xa to 5xd and 5ya to 5yd are provided. Furthermore, the pump 23 which supplies a fluid to each space is provided, and hydraulic oil is sent from this pump 23 to the 2 position control valves 21a-21d which control the flow of the fluid in each space through the pump passage 25. In the middle of the pump passage 25, flow control valves 22a to 22d for controlling the flow rate of the fluid to each space are provided. Further, the fluid discharged from each space is stored in the tank 24 through the return passage 26. Based on the detected pressure in each space, the operation states of the two-position control valves 21a to 21d, the flow control valves 22a to 22d and the pump 23 are controlled, and the rotation center line of the rotor 3 and the center line of the stator 4 are controlled. And a controller 30 that controls the same axis.

  In this embodiment, the rotor 3 is provided with a permanent magnet and the stator 4 is provided with a coil, but conversely, the rotor 3 may be provided with a coil and the stator may be provided with a permanent magnet.

  Next, the operation will be described.

  When an external force is applied to the rotor 3 via the rotated member such that the center line X1 of the rotor 3 is shifted (eccentric) in the direction perpendicular to the rotor shaft 2 with respect to the center line X2 of the case 5. The pressure change in each of the spaces 5xa to 5xd and 5ya to 5yd due to eccentricity is detected by the detection values of the pressure sensors 20a to 20d, and the controller 30 is controlled to maintain the same center line of the rotor 3 and the stator 4. To do. Specifically, it is determined that the space whose pressure has increased due to the displacement of the rotor 3 has been deformed by an external force, and the pump 23 is operated. The hydraulic oil discharged from the pump 23 is sent to the two-position control valve through a flow control valve that is controlled to a predetermined opening so that each space has the same volume according to the pressure difference. Supplied in the space.

  In this way, the fluid is supplied into the predetermined space to increase the pressure so that the position of the center line X1 of the rotor 3 is returned to the position before the eccentricity, which is the same as the center line X2 of the stator 4. To do. The center line X1 of the rotor 3 and the center line X2 of the stator 4 are the same by controlling the pressure in each space, such as reducing the pressure in the space facing the predetermined space where the pressure is increased. You may control so that it may become a centerline.

  Therefore, even if the position of the rotated body is not uniquely determined such that the rotor shaft 2 is connected to the rotated body via a constant velocity joint, for example, the center line X1 of the rotor 3 and the stator 4 The center line X2 can be the same center line. Further, when the rotor shaft 2 is directly connected to the rotated body, the rotor shaft 2, that is, the center line X 1 of the rotor 3 and the center line X 2 of the stator 4 are eccentric due to an external force acting on the rotated body. Even in this case, the eccentricity is corrected by the pressure control of the controller 30, and the center line X1 of the rotating body 3 and the center line X2 of the stator 4 can be controlled to be the same.

  FIG. 7 is a cross-sectional view illustrating the configuration of the third embodiment.

  In the first embodiment, the space between the case 5 and the support member 15 connected to the rotor 3 is supported by using the partition plate 17 and the biasing means 17a. However, in this embodiment, the partition plate 17 and the biasing member are biased. Instead of the means 17a, a plurality of bag-like elastic members 25 in which a fluid is sealed are arranged in the annular spaces 5x1 and 5y1 between the support member 15 and the case 5.

  The configuration of this embodiment has the same effect as that of the first embodiment, and only a plurality of ball-like elastic members 25 are arranged in the annular spaces 5x1 and 5y1, and therefore, compared to the first embodiment. Thus, the configuration is easy, the assembly is easy, and the cost can be reduced.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

It is sectional drawing explaining the structure of the axial direction air gap type | mold electric motor 1 of this invention. It is a block diagram of a rotor. It is sectional drawing of the cross section AA of FIG. It is sectional drawing explaining the structure of 2nd Embodiment. It is sectional drawing of the cross section BB of FIG. It is the schematic explaining the structure of the hydraulic system of 2nd Embodiment. It is sectional drawing explaining the structure of 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Axial direction gap | interval motor 1a Motor part 2 Rotor shaft 3 Rotor 4 Stator 5 Case 6 Arm part 7 Ring member 8 Yoke 9 Teeth part 10 Coil 11 Partition plate 12 Permanent magnet 13 Bearing 14 Gap 15 Support member 17 Partition plate 18 Biasing means 25 Elastic member 30 Controller

Claims (5)

A rotor in which one of permanent magnets or coils is installed at a predetermined interval in the circumferential direction;
A stator provided with the other of the permanent magnet or the coil so as to face one of the permanent magnet or the coil in the direction of the center line of the rotor,
In the axial gap type electric motor having an electric motor portion arranged so that the stator has a predetermined gap in the direction of the center line of the rotor and faces the rotor,
A case in which the rotor and the stator are internally provided, and the stator is fixed;
A bearing that allows sliding of the rotor in a direction orthogonal to the center line of the case between the case and the rotor, and enables rotation around the center line of the rotor;
A ring member provided on the outer peripheral side of the rotor;
A support member arranged coaxially with the ring member and rotatably relative to the outer periphery of the ring member;
An urging force is generated between the inner surface of the case and the support member in a direction perpendicular to the center line of the rotor so that the center line of the rotor and the center line of the stator become the same center line. A biasing means for biasing;
An axial gap type electric motor characterized by comprising: An annular space partitioned between the support member and the case is partitioned into a plurality of spaces in the circumferential direction of the rotation shaft, and a partition plate provided swingably on the support member is provided.
2. The axial gap type electric motor according to claim 1, wherein the urging means elastically presses and contacts the partition plate to the case.   2. The axial gap motor according to claim 1, wherein the biasing means is an elastic member disposed in the annular space and sealed with a fluid having a predetermined pressure. Each of the spaces is held in a sealed state,
Means for supplying or discharging fluid in each space;
Means for detecting or estimating the pressure in each space;
Based on the pressure change in each space due to the deviation in the orthogonal direction between the center line of the rotor and the center line of the stator, the axial center of the center line of the rotor and the center line of the stator The axial gap type electric motor according to claim 2, further comprising a controller that controls a pressure in each space so as to correct a deviation.   2. The axial gap type electric motor according to claim 1, wherein the bearing is provided between a surface provided orthogonal to the center line of the case and a rotor facing the surface. 3. .