JP5319912B2 - Electric motor - Google Patents

Description

  The present invention relates to an electric motor.

  Conventionally, as an electric motor that exhibits 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 a rotation axis direction (see Patent Document 1). The axial gap type electric motor includes a stator around which a coil is wound, and a rotor that is arranged to face the coil in the direction of the rotation axis and in which a plurality of pairs of permanent magnets are arranged in the circumferential direction. A current is passed through the coil to generate a rotating magnetic field, and the rotor is rotated by a magnetic attraction and repulsion force between the stator and the rotor.

A yoke constituting the stator of such an axial gap type electric motor is integrally formed with a tooth around which a coil is wound by resin molding, and its outer peripheral surface is fitted into the housing.
Japanese Patent Laid-Open No. 7-264832

  However, since an attractive force based on the magnetic force of the permanent magnet of the rotor acts on the stator, it is pulled to the rotor side, and it is necessary to fix the stator to the housing with a bolt in order to resist this tensile force. . For this reason, an increase in the size of the electric motor and an increase in weight may be caused, and by fastening the stator with bolts, a compression stress may be generated in the stator, resulting in a resistance of the magnetic circuit and a decrease in the output of the electric motor. There is.

  The present invention has been made in view of the above-described problems, and an object thereof is to efficiently support a stator against a tensile force without causing an increase in size of an electric motor.

The present invention includes a rotor that has a rotating shaft and rotates the rotating shaft, a stator that is disposed around the rotating shaft so as to face the rotor, the rotor and the stator. A case that is internally provided and that fixes the stator on the inner surface, an inner surface of the case that faces the rotor in the axial direction, and a flange surface around the stator that faces the rotor in the axial direction. A pressing member that is disposed ; and a pin that is inserted into a hole formed in the case and that supports one end of the pressing member on the case, and the pin supports one end of the pressing member on the case. And a position where the other end of the pressing member abuts on the flange surface is disposed offset in the radial direction .

  In the present invention, there is provided a pressing member disposed across the inner surface of the case facing the rotor in the axial direction and the inner surface of the stator facing the rotor in the axial direction, and the stator by the magnetic force of the rotor Therefore, the stator can be securely held in the case without increasing the size of the electric motor and without lowering the output of the electric motor.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a sectional view of an axial gap type electric motor 1 of the present invention.

  The axial gap type electric motor 1 is provided so as to face a rotating shaft 2 connected to a rotating member (not shown), a rotor 3 that rotates the rotating shaft 2, and the rotating shaft 2 facing the rotating shaft 2 with a predetermined gap. And a pair of stators 4, which are housed in a case 5.

  The rotary shaft 2 is rotatably supported by the case 5 via bearings 6 and 7 supported by cylindrical support walls 5 a and 5 b of the case 5. One end of the rotating shaft 2 protrudes from the case 5 and is coupled to a rotated member (not shown). A sensor 8 that detects the rotational speed of the rotary shaft 2 is installed inside the support wall 5a so as to face the other end of the rotary shaft 2.

  The rotor 3 is formed in a disk shape, is fixed to the outer peripheral surface of the rotating shaft 2, and is disposed at the substantially center in the axial direction in the case 5. On the rotor 3, permanent magnets (not shown) are arranged at equal intervals in the circumferential direction, and the teeth 11 of the stator 4 are arranged so as to face the permanent magnets.

  The stator 4 is formed of a core 13 fixed to the case 5 and a plurality of coils 10 disposed on the core 13. The core 13 includes a plurality of teeth 11 around which the coil 10 is wound via an insulating material, and an annular yoke 12 that fixes the teeth 11 to the case 5, and is disposed facing the rotor 3 from both sides in the axial direction. Is done.

  Each tooth 11 of the core 13 protrudes from the yoke 12 toward the rotor 3 and faces the rotor 3 with a predetermined gap in the axial direction.

  Referring to FIG. 2, the teeth 11 are arranged at predetermined intervals in the circumferential direction, and the coils 10 are wound around the teeth 11 via an insulating material (not shown). In a state where the coil 10 is wound around the teeth 11, the core 13 and the coil 10 are integrally formed with a mold resin. After molding, the outer and inner peripheral surfaces of the annular yoke 12 are fitted into the annular grooves 15 and 16 formed in the inner surface of the case 5 and opened in the axial direction. It is also possible to divide the core 13 in the circumferential direction.

  The case 5 in which the rotor 3 and the stator 4 are housed includes a bottomed cylindrical main body 5c and a lid 5d that closes the opening of the main body 5c. A through hole 14 through which the rotary shaft 2 passes is formed in the lid 5d. Annular grooves 15 and 16 into which the yoke 12 is fitted are formed on the bottom surface of the main body 5c and the inner peripheral surface of the lid 5d.

  In such an electric motor 1, the stator 4 is arranged on both sides so as to face the rotor 3, and therefore when the magnetic force of the permanent magnet provided in the rotor 3 increases, the stator 4 moves to the rotor 3. The pulling force that is directed acts.

  In order to hold the stator 4 in the case 5 against the pulling force, in the present invention, the outer circumferential flange surface 12b of the yoke 12 facing the rotor 3 and the inner surface 5e of the case 5 are straddled in the axial direction. The holding plate 18 is provided. Referring to FIG. 3, one end of the pressing plate 18 is cantilevered by the case 5 by a pin 19, and the other end is disposed in contact with the outer peripheral flange surface 12 b of the yoke 12. The pin 19 is inserted into an axial hole 20 formed in the case 5.

  As shown in FIG. 3, the pressing plate 18 is supported by the case 5 via a pin 19 and contacts only the outer peripheral flange surface 12 b of the yoke 12. With such a configuration, when the yoke 12 is pulled toward the rotor 3 by the magnetic force of the rotor 3, the moment M generated by the tensile force F causes the bending force to act on the pin 19, and the pin 19 becomes the case. I can't get out of 5. As shown in FIG. 4, the pressing plate 18 can also be formed so as to be in contact with the outer peripheral flange surface 12 b of the yoke 12 and the inner surface 5 e of the case 5.

  The holding plate 18 is arranged so that the bisector L of the angle formed by the center lines C1 and C2 passing through the center of the rotating shaft 2 of the adjacent teeth 11 passes through the center. The presser plates 18 are arranged uniformly in the circumferential direction, and the number and size of the presser plates 18 are set according to the magnitude of the magnetic force. Further, the position of the pressing plate 18 is not limited to the position between the outer peripheral side of the yoke 12 and the case 5, but can be disposed across the inner peripheral side of the yoke 12 and the case 5, or can be disposed on both sides. . When the core 13 is divided in the circumferential direction, the number of the pressing plates 18 can be reduced if the pressing plates 18 are arranged so as to press the boundary surface between the adjacent cores 13.

  In addition, as shown in FIG. 5, it is also possible to arrange | position the pin 19 which supports the pressing board 18 to the case 5 so that the fitting surface 17 of the yoke 12 and the case 5 may be included seeing from an axial direction. Specifically, substantially semicircular recesses 12 c and 5 f are provided in the outer peripheral surface 12 a of the yoke 12 and the annular groove 16 of the case 5. These recesses 12c and 5f face each other to form a hole 20 having a circular cross section in the axial direction. The pin 19 is inserted into the hole 20.

  Further, the pressing plate 18 may be formed in a ring shape concentric with the outer peripheral surface 12a or the inner peripheral surface so that at least one of the inner peripheral flange surface or the outer peripheral flange surface 12b of the yoke 12 is entirely suppressed.

  Next, the operation will be described.

  In the axial gap type electric motor of the present invention, for example, the coil 5 of the stator 4 is energized with the case 5 fixed and the rotating shaft 2 fixed to the rotor 3 connected to the member to be rotated. When the coil 10 of the stator 4 is energized, a rotating magnetic field is generated, and the rotor 3 rotates in a predetermined direction due to the magnetic attraction and repulsion between the stator 4 and the rotor 3. To do. With this rotation, the rotating shaft 2 also rotates.

  The magnetic force of the permanent magnet provided on the rotor 3 exerts a pulling force toward the rotor 3 on the stator 4 facing the rotor 3. For this reason, in the present invention, in order to resist this tensile force F, a pressing plate 18 disposed across the boundary between the yoke 12 of the stator 4 and the case 5 is provided.

  Since the pressing plate 18 is provided across the inner surface 5e of the case 5 and the outer peripheral flange surface 12b or the inner peripheral flange surface of the stator 4 facing the rotor 3 in the axial direction, the size and weight of the motor 1 can be increased. While suppressing the increase, it is possible to reliably prevent the stator 4 from being displaced toward the rotor 3 side.

  The pressing plate 18 is supported by the case 5 by pins 19 provided along the axial direction, and a position where the pin 19 is supported by the case 5 and a position where the tensile force F due to the magnetic force of the permanent magnet acts on the pressing plate 18. Are arranged offset in the radial direction. For this reason, the tensile force F acts on the pin 19 as a moment M, and this moment M acts a bending force on the pin 19 and consequently prevents the pin 19 from coming out of the case 5. With such a configuration, the dimensional tolerance of the hole 20 of the case 5 into which the pin 19 is inserted can be set large.

  The hole 20 is preferably formed so as to include a fitting surface 17 between the outer peripheral surface 12 a of the yoke 12 and the annular grooves 15 and 16 of the case 5. In this case, the effect of preventing the relative displacement of the yoke 12 around the rotation axis 2 with respect to the case 5 can also be obtained.

  Since the pressing plate 18 is disposed so as to be centered on the bisector L of the angle formed by the center lines C1 and C2 passing through the axis of the adjacent teeth 11, the compression that occurs when the yoke 12 is supported. Since the stress is generated at a position relatively far from the magnetic circuit, a decrease in the output of the electric motor 1 can be suppressed.

  By arranging the pressing plates 18 at equal intervals in the circumferential direction, the pressing plates 18 can be miniaturized and the compressive stress acting on the yoke 12 can be dispersed. Therefore, a more preferable effect can be obtained with respect to the increase in size and weight of the electric motor 1. Furthermore, when the core 13 is divided and formed, the number of the pressing plates 18 is reduced by arranging the pressing plates 18 between the adjacent cores 13 and the increase in the weight of the electric motor 1 is suppressed. can do.

  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 sectional drawing of the cross section AA of FIG. It is sectional drawing of the cross section BB of FIG. It is another sectional view of section BB of Drawing 2. It is another sectional view of section BB of Drawing 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Axial direction gap | interval motor 2 Rotating shaft 3 Rotor 4 Stator 5 Case 5c Main part 5d Lid 5e Inner surface 10 Coil 11 Teeth 12 Yoke 12a Outer peripheral surface 12b Inner surface 13 Core 15 Annular groove 16 Annular groove 17 Fitting surface 18 Presser Board 19 pin

Claims (5)

A rotor having a rotating shaft and rotating the rotating shaft ;
A stator disposed around the rotation axis so as to face the rotor;
A case in which the rotor and the stator are internally provided, and the stator is fixed to an inner surface;
A pressing member disposed across the inner surface of the case facing the rotor in the axial direction and the flange surface around the stator facing the rotor in the axial direction ;
A pin inserted into a hole formed in the case and supporting one end of the pressing member to the case;
An electric motor characterized in that a position where the pin supports one end of the pressing member on the case and a position where the other end of the pressing member abuts on the flange surface are offset in the radial direction . The hole formed in the case is formed across an inner surface of the case and a flange surface around the stator facing the rotor in an axial direction. Electric motor. The stator includes a core supported by the case, and a coil wound around the core,
The electric motor according to claim 1, wherein the pressing member is disposed across the core and the case. 4. The electric motor according to claim 1, wherein one end of the pressing member is supported by the case via a pin that penetrates the pressing member in the axial direction. The core is formed by being divided in the circumferential direction,
The electric motor according to claim 4, wherein the pressing member is disposed so as to contact a boundary surface between adjacent divided cores.

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