JP2009130945A - Motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor equipped with a constitution for blocking displacement of a stator relative to a case. <P>SOLUTION: A motor comprising a rotor 3 having a rotating shaft 2, a stator 4 arranged to face the rotor, and a case 5 for housing the rotor and the stator and fixing the stator to the inner surface thereof, is further provided with a pin 18 parallel with the rotating shaft and coupled with the case and the stator by means of a key. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

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.

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

  However, in the conventional fixing structure of the yoke, when the output of the electric motor increases, the reaction force of the rotational force of the rotor acts on the yoke, which may cause a relative displacement between the yoke and the housing. In order to prevent relative displacement, the housing and the yoke may be fixed with bolts. In this case, however, the stator becomes larger and the weight increases, and further, compression stress acts on the yoke by bolting. Therefore, it becomes a resistance of the magnetic circuit, and there is a possibility that the output of the motor is reduced.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an electric motor that can support a large torque reaction force without causing an increase in the size of the electric motor or a decrease in output.

  The present invention includes a rotor having a rotation shaft, a stator disposed so as to face the rotor, the rotor and the stator, and a case for fixing the stator to an inner surface thereof. The motor is characterized in that a pin parallel to the rotating shaft and key-coupled to both the case and the stator is provided.

  In the present invention, a pin arranged across the case and the stator is provided, and the relative displacement around the rotation axis between the stator and the case due to the reaction force of the rotational force generated when the rotor rotates is suppressed. A large torque reaction force can be supported without increasing the size of the electric motor or reducing the output.

  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 rotation member (not shown), a rotor 3 that rotates the rotating shaft 2, and the rotating shaft 2 so as to face the rotating shaft 2 with a predetermined gap in the axial direction. 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 fitted to the outer peripheral surface of the rotating shaft 2, and is disposed at a substantially axial center 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. The core 13 is disposed on the rotor 3 as desired 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 coil 10 is 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 stator 4 is fixed to the case 5 by fitting the outer peripheral surface of the annular yoke 12 into the annular grooves 15 and 16 formed in the inner surface of the case 5 and opening 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.

  Thus, the stator 4 is fixed to the case 5 by fitting the yoke 12 into the annular grooves 15 and 16. However, the reaction force of the rotational force of the rotor 3 increases due to the increase in the output of the electric motor 1, and this reaction force tries to rotate the yoke 12 around the axis with respect to the case 5. When the reaction force increases, the inner and outer peripheral surfaces of the yoke 12 slide in the circumferential direction with respect to the annular grooves 15 and 16, and there is a possibility that relative displacement occurs between the stator 4 and the case 5.

  In order to solve such a problem, in the present invention, a pin 18 that prevents relative displacement of the yoke 12 and the case 5 around the central axis of the rotating shaft 2 is installed in the axial direction.

  2 and 3, a plurality of substantially semicircular recesses 19a and 19b are formed in the annular groove 15 of the case 5 and the outer peripheral surface 12a of the yoke 12 in the axial direction. The holes 19 having a circular cross section are formed by facing each other. Then, the pins 18 are respectively inserted into the holes 19 so that the case 5 and the yoke 12 are key-coupled.

  The hole is centered at the intersection of the bisector L of the angle formed by the center lines C1 and C2 passing through the axis of the adjacent teeth 11 and the fitting surface 17 between the annular groove 15 and the outer peripheral surface 12a of the yoke 12. It is formed to become. These holes 19 are desirably formed uniformly in the circumferential direction, and the number, diameter, etc. are set according to the magnitude of the reaction force. The hole portion 19 can be formed not only between the annular groove 15 and the outer peripheral surface 12a of the yoke 12, but also between the annular groove 15 and the inner peripheral surface of the yoke 12, or both. In addition, when the core 13 is formed by being divided in the circumferential direction, the number of pins 18 is reduced by forming the hole portion 19 so as to include the boundary surface between the fitting surface 17 and the adjacent core 13. can do.

  A similar hole portion 19 is formed between the annular groove 16 and the yoke 12, and the pin 18 is inserted.

  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.

  Since the rotating shaft 2 is connected to a rotated member (not shown), the rotational reaction force of the rotated member acts on the stator 4. This reaction force acts as an external force that causes a slip in the circumferential direction on the fitting surface 17 between the case 5 and the yoke 12 of the stator 4. Therefore, in the present invention, a pin 18 is inserted into a hole formed in the axial direction so as to include the fitting surface 17 between the case 5 and the yoke 12, and this pin 18 causes a reaction force during rotation of the rotor 3. Relative displacement between the stator 4 and the case 5 is prevented. With this structure, it is possible to suppress relative displacement between the stator 4 and the case 5 while suppressing increase in size and weight of the motor.

  Since the hole is arranged so that the intersection of the bisector L of the angle formed by the center lines C1 and C2 passing through the axis of the adjacent teeth 11 and the fitting surface 17 is the center, the reaction force is supported. As a result, the compressive stress generated in the yoke 12 is generated at a position relatively far from the magnetic circuit. Therefore, the output reduction of the electric motor 1 due to the compressive stress can be suppressed to a small level.

  Further, by arranging the plurality of hole portions at equal intervals in the circumferential direction, the pin 18 inserted into the hole portion can be reduced in size, and the compressive stress is dispersed. Therefore, more preferable effects can be obtained with respect to the increase in the size of the motor and the suppression of the increase in weight.

  FIG. 4 is a diagram illustrating the configuration of the pin 20 that supports the stator 4 against the reaction force according to the second embodiment.

  The pin 18 of the first embodiment shown in FIG. 3 is formed with a hole so as to include the fitting surface 17 between the case 5 and the yoke 12, but in the second embodiment, the hole is a fitting surface. 17 is formed on both sides of the joint surface of the case 5 and the yoke 12 in the axial direction, and the pins 20 are inserted into the holes. By setting it as such an arrangement | positioning, the freedom degree of arrangement | positioning of the pin 20 can be increased.

  The shape of the holes 18 and the pins 18 and 20 inserted into the holes is not limited to a circle. Any shape in which the hole and the pin can be key-coupled is applicable.

  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. For example, it is apparent that the present invention can be applied not only to the axial gap type electric motor but also to an electric motor in which a stator is arranged on the outer peripheral side of the rotor.

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 a figure explaining the pin which supports the torque reaction force as 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Axial direction gap | interval motor 2 Rotating shaft 3 Rotor 4 Stator 5 Case 10 Coil 11 Teeth 12 Yoke 13 Core 14 Through-hole 15, 16 Annular groove 17 Fitting surface 18 Pin 19 Recessed part

Claims (5)

A rotor with a rotation axis;
A stator arranged to face the rotor;
In the electric motor provided with a case for internally arranging the rotor and the stator and fixing the stator to the inner surface thereof,
An electric motor comprising a pin parallel to the rotating shaft and key-coupled to both the case and the stator. The stator includes a core fixed to the case and the coil wound around the core, and is disposed so as to face the rotor in the axial direction.
The electric motor according to claim 1, wherein the pin is key-coupled to both the core and the case. The case includes an annular groove that opens in an axial direction of the rotating shaft on an inner surface,
The core includes a yoke that is annularly formed and fits into the annular groove;
The electric motor according to claim 2, wherein the pin is inserted into a hole formed in an axial direction across a fitting surface between the yoke and the case. The core is formed by being divided in the circumferential direction,
4. The electric motor according to claim 3, wherein the pin is inserted into a hole formed at an intersection between a boundary surface between adjacent divided cores and the fitting surface. 5. The core is composed of a yoke fixed to the case and a plurality of teeth around which the coil is wound,
4. The electric motor according to claim 3, wherein the pin is inserted into a hole formed at an intersection of a bisector of each center line of the adjacent teeth and the fitting surface. 5.

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