JP2010051159A - Variable field motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a weight-reduced and maintenance-free variable field motor. <P>SOLUTION: The variable field motor has rotors 4 mounted on bases 1, 2 in a freely rotational manner, stators 9 mounted in a free displacement manner coaxially and axially with the rotors, and a stator moving means for shifting the stator axially. The stator moving means has many rotary members 7 that are disposed around axis lines of the rotors while being axis-supported on the bases in a rotatable manner and being provided with either male screws or female screws, slide members 8 that are screwed with either the male screws or female screws and are integrally mounted on the stators, a drive means 15 for rotary driving of at least one of rotary members, pulleys 12 fixed at one end side for each of rotary members, and belts 13 rolled between the pulleys 12. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a variable field motor having a stator that can be displaced in the axial direction of a rotor.

2. Description of the Related Art Conventionally, there is a variable field motor that can adjust a field of a motor and obtain an appropriate rotation speed and torque according to a use situation, and is used, for example, in an electric vehicle. The same applicant proposes such a variable field motor, in which a stator is provided so as to be displaceable in the axial direction of the rotor, and the field is changed by changing the relative position of the stator with respect to the rotor. (For example, refer to Patent Document 1).
Japanese Patent Application No. 2006-335502

  Since the motor receives the driving torque of the rotor by the stator, the stator in the variable field motor having the above structure needs to have two functions of displacing the stator in the axial direction and receiving torque in the rotational direction. . In the above-mentioned Patent Document 1, both the cylindrical fixing member that surrounds the rotating shaft of the rotor and the stator are splined together to realize axial displacement and torque reception of the stator.

  However, in the stator moving means for displacing the stator, a male screw member rotatably supported on the base and a slide member provided with a female screw that is screwed to the male screw member are integrally provided on the stator. In addition to the spline structure, the structure is complicated, and the weight increases due to an increase in the number of parts, which makes it difficult to reduce the weight.

  In addition, since maintenance is troublesome due to the complexity of the structure and the increase in the number of parts, there is a demand that it is desirable to make it maintenance-free as much as possible.

  In order to solve the above-mentioned problems, the present invention provides a rotor (4) rotatably provided on a base (1, 2) and a stator (coaxial with respect to the rotor and displaceable in the axial direction of the rotor). 9) and a stator moving means for displacing the stator in the axial direction, the stator moving means being arranged around the axis of the rotor and rotatably supported by the base, Rotating at least one of the plurality of rotating members (7) provided with one of the female screws, the slide member (8) screwed into one of the male screw and the female screw and provided integrally with the stator A driving means (15) for driving, a pulley (12) fixed to one end side of each of the plurality of rotating members, and a belt (13) wound between the pulleys That.

  According to this, as a stator moving means for displacing the stator in the axial direction of the rotor, a rotating member pivotally supported on the base and a slide member integrally provided on the stator are provided, and both the members are screwed together. Since a plurality of rotating members are arranged around the axis of the rotor, the stator that receives the counter torque of the rotational torque of the rotor can be easily supported by the plurality of rotating members. Furthermore, by rotating a plurality of rotating members in synchronization, the stator can be displaced via a slide member screwed to the rotating member, and a torque receiving mechanism and a stator displacing mechanism are not provided separately. In other words, a single mechanism can serve both as a torque receiver and a stator displacement, and the increase in the number of parts is suppressed, so the weight of the variable field motor is reduced and maintenance is made free by reducing the number of parts that require maintenance. Is promoted. Further, since the drive transmission between the plurality of rotating members is performed by the belt, lubrication can be omitted, and maintenance-free operation is further promoted.

  According to the present invention, it is possible to provide a variable field motor that has a simple structure and is maintenance-free.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of a main part of a drive wheel of an electric vehicle to which the present invention is applied as viewed from a direction orthogonal to a rotation axis. FIG. 2 is an end view of a main part viewed from the line II of FIG. FIG. 3 is an end view of the main part viewed from the arrow III line of FIG. Note that FIG. 1 is not broken so as to be vertically symmetrical with respect to the rotation axis in the figure, but is broken so that the main part is shown in the upper and lower cross sections. Further, as shown in the figure, the variable field motor may be configured as an in-wheel motor of an electric vehicle.

  A disc-shaped motor mounting base 1 as a base is fixed to a swing arm (knuckle) 100 on the vehicle body side. A cylindrical fixed support shaft 2 projecting to the side of the vehicle body is fixed to the motor mounting base 1, and the rotor 4 is disposed on the inner peripheral side of the fixed support shaft 2 via a pair of bearings 3 a and 3 b. The rotor shaft 4a is rotatably supported. The bearings 3a and 3b are preferably bearings capable of resisting radial loads and thrust loads, and are, for example, angular ball bearings or tapered roller bearings.

  The rotor 4 is formed so as to coaxially surround the rotor shaft 4a at the outer peripheral portion of the disc portion 4b and the disc portion 4b formed in an outward flange shape at the axial end of the rotor shaft 4a. And a peripheral wall portion 4c. Drive wheels are attached to the disc portion 4b via wheels.

  A first outward flange 6a projecting radially from the projecting end side of the fixed support shaft 2 so as to face the outer peripheral portion of the fixed support shaft 2 with a predetermined distance in the axial direction of the rotor shaft 4a, A second outward flange 6b protruding from the end side in the radial direction of the fixed support shaft 2 is formed. As shown in FIG. 2, the first and second outward flanges 6a and 6b are arranged at three locations at equal intervals of 120 degrees around the axis of the rotor shaft 4a. Each of the first and second outward flanges 6a and 6b is formed with a hole 6c at an opposing position, and a rotating member 7 is rotatably provided in each hole 6c via a bearing 6d and 6e. ing. The end of the rotating member 7 on the side of the vehicle body extends through the hole 6c to the side of the vehicle body side of the first outward flange 6a. One of the rotating members 7 extends through the second outward flange to the vehicle body side. The rotating member 7 is formed with a male screw portion 7a made of a trapezoidal screw. The bearings 6d and 6e are preferably bearings capable of resisting radial loads and thrust loads, and are, for example, angular ball bearings or tapered roller bearings.

  A hall IC 19a and a sensor substrate 19b constituting the rotation sensor 19 are provided on the surface of the first outward flange 6a on the side of the vehicle body, and the rotation sensor 19 is provided at a position facing the hall IC 19a of the disc portion 4b of the rotor 4. A constituting magnet 19c is provided.

  Each rotating member 7 is assembled with a slide member 8 formed with a female screw portion 8a that is screwed into the male screw portion 7a. The slide member 8 is preferably a member that does not require lubrication (oil-free type), and is formed of, for example, a resin material. As the resin material, polyacetal resin, polyamide resin, or the like is used. A ring-shaped stator 9 is integrally fixed to each slide member 8. Thereby, when the rotating member 7 rotates, the slide member 8 reciprocates in the axial direction of the rotating member 7, and the stator 9 can reciprocate integrally.

  The stator 9 is wound around each stator core 9b, an annular stator base 9a fixed to each slide member 8, a plurality of stator cores (teeth) 9b projecting radially outward from the stator base 9a. And a predetermined number of coils 9c. A predetermined number of magnets 11 are arranged on the inner peripheral surface of the peripheral wall 4c of the rotor 4 alternately with N and S poles in the circumferential direction. In the illustrated example, a 32-pole 36-slot motor is shown, but the present invention is not limited to this.

  A first pulley 12 is fixed to the end of each rotating member 7 on the side of the vehicle body, and a first endless belt 13 is wound around each first pulley 12 as shown in FIGS. It has been. The first endless belt 13 is a flat belt, a round belt, a V belt, a toothed belt (cogged belt), or the like, and is particularly preferably a toothed belt. When a toothed belt is used for the first endless belt 13, teeth corresponding to the tooth shape of the toothed belt are formed on each first pulley 12.

  A second pulley 14 is formed at the end of the rotating member 7 that passes through the second outward flange 6b and extends toward the vehicle body. A motor-driven actuator 15 is attached to the motor mounting base 1 via a bracket 16. A drive pulley 17 is provided on the output shaft of the actuator 15. A second endless belt 18 is wound between the second pulley 14 and the drive pulley 17. The second endless belt 18 may be the same as the first endless belt 13 described above.

  In this way, the slide member 8 can be displaced to an arbitrary position in accordance with the drive control signal to the actuator 15. The rotation of the driving pulley 17 is transmitted to the second pulley 14 via the second endless belt 18, and the rotation of the rotating member 7 provided with the second pulley 14 is transmitted to the other pulley via the first pulley and the first endless belt 13. Since it is transmitted to the rotating member 7, all the rotating members 7 are rotated in synchronization by the rotational drive of the actuator 15. Therefore, the slide member 8 provided in each rotary member 7 and the movement amount of the stator 9 fixed to the slide member 8 are the same, and the stator 9 is moved while maintaining a posture orthogonal to the rotor shaft 4a. The

  Further, even if an external force that is displaced in the sliding direction acts on the slide member 8 due to the lead angle between the male screw portion 7a and the female screw portion 8a or the frictional resistance of the other belt transmission portion, it is driven and stopped by the actuator 15 In addition, the slide member 8 can be held in a stopped state.

  The solid line in FIG. 1 indicates the position where the opposing area between the magnetic pole surface of the magnet 11 and the facing surface facing the magnetic pole surface of the stator core 9b is maximized. By displacing the stator 9 from the position toward the vehicle body side in the axial direction of the rotor shaft 4a, the above-described opposing areas of the magnet 11 and the stator core 9b are reduced. Further, the stator 9 can be moved to the outer side of the vehicle body from the position where the opposing areas of the magnetic pole surface of the magnet 11 and the facing surface of the stator core 9b are reduced.

  The amount of displacement of the stator 9 is the position at which the opposing surface of the stator core 9b completely overlaps with respect to the magnetic pole surface of the magnet 11 in the axial direction of the rotor shaft 4a as shown in FIG. It may be between two positions with the position shown. In the illustrated example, the displacement amount from the completely overlapping position is about 50% when the displacement amount to the completely deviated position is set to 100%, but it is an arbitrary position up to 0%. good. In the case of the 50% position, the amount of overlap in the linear direction of the rotor shaft 4a between the magnetic pole surface of the magnet 11 and the facing surface of the stator core 9b is halved.

  When the motor is driven, the stator 9 receives a counter torque against the rotational torque of the rotor 4. According to the structure described above, since the stator core 9b is supported by the three rotating members 7 in the illustrated example arranged at a predetermined angle around the axis of the rotor shaft 4a, three counter torques acting on the stator 9 are provided. Can be received by the rotating member 7.

  When the stator core 9 b of the stator 9 is displaced with respect to the magnet 11, a force is applied in a direction in which the stator 9 is pulled inward of the rotor 4. Therefore, force is applied to the bearings 3a and 3b and the bearings 6d and 6e in the thrust direction. Since the bearings 3a and 3b and the bearings 6d and 6e are formed of angular ball bearings or tapered roller bearings, they can withstand thrust force, maintain smooth rotation of the motor, and maintain a long service life of the motor. Can be achieved.

  In the present embodiment, since the first pulley 12 and the first endless belt 13 are disposed so as to surround the space where the Hall IC 19a, the sensor substrate 19b, and the magnet 19c of the rotation sensor 19 are provided, the storage efficiency of each device is improved. The motor can be made thinner.

  The stator moving means is configured by using the belts 13 and 18 and the pulleys 12 and 14, and the slide member 8 does not require lubrication. Therefore, the stator moving means according to the present embodiment can omit supply of lubricating oil. Therefore, the dust-proof and waterproof structure of the stator moving means can be omitted and maintenance-free can be achieved.

  Therefore, it is not necessary to have a structure that receives the counter torque from the serration or spline as in the conventional case, and the counter torque can be received by using the displacement mechanism of the stator 9 required in the variable field motor, and the increase in the number of parts is suppressed. However, since the weight reduction can be promoted, the cost can be reduced. In addition, since there are no unnecessary parts, it is possible to promote the realization of maintenance-free operation and to reduce the thickness of the motor.

  Although the description of the specific embodiment is finished as above, the present invention is not limited to the above embodiment and can be widely modified. For example, all the rotating members 7 may pass through the second outward flange 6b and protrude toward the vehicle body side of the second outward flange 6b, and the first pulley and the first endless belt may be provided in the protrusion. In this embodiment, three rotating members 7 are arranged at equal intervals around the rotor shaft 4a. However, in other embodiments, the number of rotating members 7 may be increased to four or five. In addition, it can change suitably in the range which does not deviate from the meaning of invention.

It is the principal part schematic sectional drawing which looked at the drive wheel of the electric vehicle to which this invention was applied from the direction orthogonal to a rotating shaft. It is the principal part end view seen from the arrow II line of FIG. It is the principal part end view seen from the arrow III line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor mounting base 2 Fixed support shaft 4 Rotor 6a, 6b 1st outward flange, 2nd outward flange 7 Rotating member 8 Slide member 9 Stator 9a Stator base 9b Stator core 9c Coil 11 Magnet 12 1st pulley 13 Belt 13 1st endless Belt 14 Second pulley 15 Actuator 17 Drive pulley 18 Second endless belt 19 Rotation sensor

Claims (1)

A variable field having a rotor provided rotatably on a base, a stator provided coaxially with the rotor and displaceable in the axial direction of the rotor, and stator moving means for displacing the stator in the axial direction. A magnetic motor,
The stator moving means is
A plurality of rotating members disposed around the axis of the rotor and rotatably supported by the base and provided with one of a male screw and a female screw;
A slide member screwed into one of the male screw and the female screw and provided integrally with the stator;
Drive means for rotationally driving at least one of the plurality of rotating members;
A pulley fixed to one end of each of the plurality of rotating members;
A variable field motor comprising: a belt wound between the pulleys.

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