JP4849328B2 - Double stator type motor - Google Patents

Description

  The present invention relates to a double stator motor.

  As one type of double stator type motor, Japanese Patent Application Laid-Open No. 3-139156 describes a double stator type motor in which a shaft, a rotor, an outer stator and an inner stator are built in a motor housing. In this double stator type motor, a shaft is rotatably incorporated in a motor housing via a bearing portion, and the rotor is coupled to rotate integrally with the shaft. Then, the outer stator is fixed to the motor housing so as to be positioned on the outer side in the rotational radial direction with respect to the rotor, and the inner stator is fixed on the motor housing so as to be positioned on the inner side in the rotational radial direction with respect to the rotor.

The rotor in this double stator type motor is provided with a circumferential surface having a circular cross section or a regular polygon. And the through-hole which penetrates the inside and outside of a rotor is arranged in the circumferential direction at this peripheral surface, and the flat permanent magnet is fitted to each through-hole. Each permanent magnet is arranged such that its outer surface faces the outer stator and its inner surface faces the inner stator.
JP-A-3-139156

  In order to obtain high torque in the conventional double stator type motor described above, it is necessary to reduce the gap between the permanent magnet of the rotor and the outer stator and the gap between the permanent magnet and the inner stator as much as possible. For this purpose, precision such as improving the dimensional accuracy of the through holes provided in the rotor peripheral surface and the permanent magnets fitted into the through holes, or polishing both the inner and outer surfaces of the permanent magnets after the permanent magnets are fitted into the through holes. It is necessary to improve the accuracy of attaching the permanent magnet to the through hole by processing. Therefore, there has been a problem that the manufacturing cost becomes high.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a low-cost double-stator type motor that secures required high accuracy and omits precision machining when attaching a permanent magnet to a through hole of a rotor. .

In order to achieve the above object, an invention according to claim 1 is directed to a shaft rotatably incorporated in a motor housing via a bearing portion, a rotor connected to rotate integrally with the shaft, and a rotor. An outer stator fixed to the housing so as to be positioned on the outer side in the rotational radial direction, and an inner stator fixed to the housing so as to be positioned on the inner side in the rotational radial direction with respect to the rotor. A through hole penetrating the inner and outer sides of the rotor is arranged in the circumferential direction on the circumferential surface, a flat permanent magnet is fitted in each through hole, and the outer surface of the permanent magnet is In the double stator type motor, which is arranged so as to face the outer stator and the inner surface of the permanent magnet is arranged so as to face the inner stator,
The length dimension in the front-rear direction extending along the rotation center line of the rotor in the permanent magnet is set shorter than the length dimension in the front-rear direction extending along the rotation center line of the rotor in the through hole,
The upper and lower inner end surfaces perpendicular to the front-rear direction in the through hole are provided with a required taper so that the opening width of the through hole gradually increases or decreases along the rotation center line of the rotor,
The upper and lower end surfaces of the permanent magnet are in close contact with the upper and lower inner end surfaces of the through hole, and the permanent magnet is fitted into the through hole.

  According to a second aspect of the present invention, in the double stator motor according to the first aspect of the invention, the opening width of the through hole gradually increases or decreases along the rotational radius direction of the rotor on the upper and lower inner end surfaces of the through hole. Is provided with a necessary taper.

  According to a third aspect of the present invention, in the double stator type motor according to the second aspect of the present invention, it is necessary that the opening width of the through hole gradually decreases toward the outer side in the rotational radial direction of the rotor on both upper and lower end surfaces of the through hole. It is characterized by providing a taper of.

  According to the first aspect of the present invention, the length of the permanent magnet is made shorter than the length of the through hole of the rotor, and the required taper is provided along the rotation center line of the rotor on both upper and lower inner end surfaces. Therefore, when incorporating the permanent magnet into the through hole, the permanent magnet can be finely moved along the direction of the rotation center line of the rotor within the through hole until the tapered surface of the permanent magnet and the tapered surface of the through hole come into close contact with each other. Accordingly, the position of the rotor inside and outside in the through hole of the permanent magnet can be finely adjusted while finely moving the permanent magnet inside the through hole, so that the gap between the permanent magnet and the outer stator and the gap between the permanent magnet and the inner stator can be adjusted. The required dimensions can be set. For this reason, it is possible to reduce the manufacturing cost by omitting high-precision processing of the through-holes and permanent magnets, or processing such as polishing the inner and outer surfaces of the permanent magnets after the permanent magnets are fitted into the through-holes.

  According to the invention described in claim 2, since the upper and lower end faces of the through hole are tapered along the rotational radius direction of the rotor, the contact area between the upper and lower end faces of the permanent magnet and the upper and lower inner end faces of the through hole is reduced. growing. For this reason, when bonding a permanent magnet to a through-hole, a permanent magnet can be firmly fixed to a through-hole by the increase in an adhesion area.

  According to the invention described in claim 3, since the upper and lower inner end faces of the through hole are tapered so that the opening width of the through hole gradually decreases toward the outer side in the rotational radius of the rotor, It is possible to reliably prevent the permanent magnet from falling off the through hole due to centrifugal force.

  The present invention will be described below with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing a double stator type motor according to an embodiment of the present invention, and shows a case where the present invention is applied to an in-wheel motor incorporated in a wheel of a vehicle and directly driving a drive wheel. FIG. 2 is an exploded perspective view showing the main part of the motor.

  The double stator motor 10 includes a motor housing 20 and a wheel shaft 30. The wheel shaft 30 passes through the motor housing 20, and a hub 31 integrally formed at one end protruding from the housing 20 and the wheel 40 are connected by a hub stud bolt 41.

  The motor housing 20 includes an outer housing 21 whose inner end surface is an opening 21 a and an inner housing 22 that covers the inner end surface opening 21 a of the outer housing 21, and the inner housing 22 is fixed to the outer housing 21 with bolts 23. The inner housing 22 is attached to the vehicle body via a vehicle suspension device (not shown). The outer housing 21 and the inner housing 22 are formed with through holes 21 b and 22 a at the center, the hub shaft 30 is inserted into the motor housing 20 from the through hole 21 b of the outer housing 21, and the tip is the through hole 22 a of the inner housing 22. Projecting to the outside of the housing 20.

  The housing 20 includes a rotor 50, a bearing portion 60 that rotatably supports the rotor 50, an outer stator 70, and an inner stator 80. As shown in FIGS. 2 and 3, the rotor 50 includes a bottomed short cylindrical rotor main body 51 and a cylindrical shaft portion 53 that protrudes integrally at the center of the bottom surface 52 of the rotor main body 51. The rotor body 51 has a circumferential surface 54 having a circular cross section, and a plurality of through holes 55 penetrating the inside and outside of the rotor are arranged in the circumferential surface 54 at equal intervals along the circumferential direction. A flat permanent magnet 56 is fitted in each through hole 55.

  FIG. 3 shows details of the shape of the through hole 55, and FIGS. 4 and 5 show details of the shape of the through hole 55 and the permanent magnet 56 fitted in the through hole 55. The through-hole 55 is punched and formed in a substantially isosceles trapezoidal shape, and flange surfaces 55 a are bent at both upper and lower inner end surfaces extending along the rotation center O of the rotor 50. The flange surface 55a is provided with a required taper so that the opening width of the through hole 55 gradually increases along the rotation center line O of the rotor as the distance from the bottom surface 52 of the rotor body 51 increases.

  The permanent magnet 56 is formed in an isosceles trapezoid having upper and lower end surfaces 56a having the same taper as the flange surface 55a of the through hole. The longitudinal dimension L1 of the permanent magnet 56 extending along the rotation center line O of the rotor is set shorter than the longitudinal dimension L2 of the through hole 55 extending along the rotation center line O of the rotor.

  The permanent magnet 56 is fixed to the through hole 55 with an adhesive. At the time of assembly, the permanent magnet 56 is loosely fitted between the upper and lower flange surfaces 55a of the through hole 55 as shown by a two-dot chain line in FIG. Then, as indicated by the solid line, the upper and lower end faces 56a of the permanent magnet 56 are finely moved along the rotation center line O of the rotor as indicated by the arrow A until the upper and lower flange faces 55a of the through hole 55 are in close contact with each other. At that time, as indicated by an arrow B in FIG. 5, the inner and outer positions of the rotor 50 in the through hole 55 of the permanent magnet 56 are finely adjusted, and the gap between the permanent magnet 56 and the outer stator 70 and the permanent magnet 56 and the inner stator 80. And set the required gap.

  1, the bearing portion 60 includes a pair of inner and outer ball bearings 61 and 62 and a cylindrical bearing case 63 in which a flange portion 63a is integrally formed at one end. The flange portion 63a of the bearing case 63 is an inner housing with a bolt 64. 22 is fixed to the peripheral edge of the central through hole 22a. Then, both ball bearings 61 and 62 and a bearing collar 65 are stored in the bearing case 63, the cylindrical shaft portion 53 of the rotor is inserted into both the ball bearings 61 and 62, and the rotor 50 is rotatably assembled to the inner housing 22. Further, a bearing collar 66 is mounted on the cylindrical shaft portion 53 and the fine nut 67 is tightened to prevent the ball bearings 61 and 62 from coming off the cylindrical shaft portion 53.

  The wheel shaft 30 is inserted into the cylindrical shaft portion 53 of the rotor 50 that is rotatably incorporated in the housing 20 by the bearing portion 60, and the serration coupling 30a is performed so that the cylindrical shaft portion 53 and the wheel shaft 30 rotate integrally. Thus, the rotor 50 and the wheel shaft 30 are rotatably incorporated into the housing 20 by the common bearing portion 60.

  The outer stator 70 includes a plurality of iron cores 71 and coils 72 wound around each iron core 71. On the other hand, a plurality of recesses 21 c are formed in a ring shape on the inner peripheral surface of the outer housing 21. Each iron core 71 constituting the outer stator 70 is fitted into the recess 21 c and is directly fixed to the inner peripheral surface of the outer housing 21. The outer stator 70 is located outside the rotational radius of the rotor 50 and is arranged and fixed on the inner peripheral surface of the outer housing 21 so as to be close to the outer surface of the permanent magnet 56.

  The inner stator 80 includes an iron core 81 provided with a plurality of convex pieces 81a radially and a coil 82 wound around each of the convex pieces 81a. The iron core 81 is directly fixed to the flange portion 63a of the bearing case 63 with a bolt 83. . The inner stator 80 is positioned on the inner side of the rotor in the radial direction of rotation, and is disposed and fixed to the inner housing 22 via the bearing case 63 so as to be close to the inner surface of the permanent magnet 56.

  The end of the wheel shaft 30 opposite to the hub passes through the cylindrical shaft portion 53 of the rotor 50, and further protrudes from the center through hole 22 a of the inner housing 22 to the outside of the housing 20. A brake drum 90 is attached to the protruding end portion by serration coupling. Reference numeral 91 denotes a seal member that seals the central through hole 21b of the outer housing 21, reference numeral 92 denotes a cover plate that covers the central through hole 22a of the inner housing 22, and reference numeral 93 denotes a central through hole of the cover plate 92. A sealing member 94 for sealing is a resolver rotor collar.

  The structure of the double stator type motor 10 according to the present embodiment is as described above. The length L1 of the permanent magnet 56 is shorter than the length L2 of the through hole 55 of the rotor 50, and the penetrating contact with the permanent magnet 56 is made. Since the upper and lower end surfaces 55a of the hole 55 are formed as flange surfaces having a taper, when the permanent magnet 56 is assembled to the through hole 55, the upper and lower end surfaces 56a having the taper of the permanent magnet 56 and the flange surface 55a of the through hole 55 are in close contact with each other. Until then, the permanent magnet 56 can be finely moved along the rotation center line O of the rotor inside the through hole 55. Accordingly, since the inner and outer positions of the permanent magnet 56 in the through hole 55 can be finely adjusted while finely moving the permanent magnet 56, the gap between the permanent magnet 56 and the outer stator 70 and the gap between the permanent magnet 56 and the inner stator 80 are required. Can be set to dimensions. For this reason, high-precision processing of the through-hole 55 and the permanent magnet 56 or processing such as polishing the inner and outer surfaces of the permanent magnet 56 after the permanent magnet 56 is fitted into the through-hole 55 is omitted to reduce the manufacturing cost. be able to.

  By the way, both the flange surfaces 55a of the through-hole 55 of the rotor 50 in the double stator motor 10 described above and the upper and lower end surfaces 56a of the permanent magnet 56 that are in close contact with the flange surface 55a are set parallel to each other as shown in FIG. . On the other hand, as shown in FIGS. 6 and 7, both flange surfaces 55 b of the through-hole 55 are formed as tapered surfaces along the rotation center line O and are in close contact with the flange surfaces 55 b and the flange surfaces 55 b of the permanent magnet 56. The upper and lower end surfaces 56b may be formed in tapered surfaces such that the opening width of the through hole 55 and the width of the permanent magnet 56 gradually increase toward the outer side in the radial direction along the rotational radius direction of the rotor. Thus, by giving a required taper to the flange surface 55 b of the through hole 55 and the upper and lower end surfaces 56 b of the permanent magnet 56, the adhesion area of the permanent magnet 56 to the flange surface 55 b increases, and the permanent magnet 56 becomes the through hole 55. Can be firmly fixed.

  Further, as shown in FIGS. 8 and 9, the upper and lower end surfaces 56 c that are in close contact with the flange surface 55 c of the through-hole 55 and the flange surface 55 c of the permanent magnet 56 are formed so as to extend radially outward along the rotational radius direction of the rotor 50. A necessary taper can be provided so that the opening width of 55 and the width of the permanent magnet 56 gradually decrease. In this way, by tapering the flange surface 55c of the through hole 55 and the both end surfaces 56c of the permanent magnet 56, it is possible to reliably prevent the permanent magnet 56 from dropping from the through hole 55 due to centrifugal force when the rotor 50 rotates at high speed. .

  Furthermore, in the above-described embodiment, the upper and lower flange surfaces 55a, 55b, and 55c of the through hole 55 and the upper and lower end surfaces 56a, 56b, and 56c of the permanent magnet 56 are both the same tapered surface. May be given.

  Also, flange surfaces are formed at both front and rear end portions of the through-hole 55. The flange surfaces are tapered opposite to the taper of the upper and lower flange surfaces 55a, 55b, 55c, and the front end or rear end of the permanent magnet 56 is brought into contact with the flange surface. By doing so, it can also be set as the structure which can hold | maintain the permanent magnet 56 still more reliably.

  In the above embodiment, the flange surfaces 55a, 55b, and 55c are formed at the upper and lower end portions of the through hole 55 to secure the bonding area, thereby holding the permanent magnet 56. However, the rotor thickness can be increased. For example, the bonding area can be secured without forming the flange surfaces 55a, 55, and 55c.

It is sectional drawing which shows the double stator type motor which concerns on one Example of this invention. It is a disassembled perspective view which shows the principal part of the motor. It is a perspective view which shows the rotor main body of the motor. It is a partial expanded side view which shows the through-hole and permanent magnet of the rotor of the motor. It is a partial expanded sectional view which shows the through-hole and a permanent magnet. It is a partial expanded side view which shows the other Example of the through-hole of a rotor of the motor, and a permanent magnet. It is a partial expanded sectional view which shows the through-hole and a permanent magnet. It is the elements on larger scale which show the other Example of the through-hole of a rotor of the motor, and a permanent magnet. It is a partial expanded sectional view which shows the through-hole and a permanent magnet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Double stator type motor 20 ... Housing 21 ... Outer housing 22 ... Inner housing 30 ... Wheel shaft 40 ... Wheel 50 ... Rotor 51 ... Rotor main body 52 ... Rotor bottom surface 53 ... Cylindrical shaft part 54 ... Rotor peripheral surface 55 ... Through-hole 55a , 55b, 55c ... both upper and lower inner end surfaces 56 of the through-holes ... permanent magnets 56a, 56b, 56c ... upper and lower end surfaces 60 of the permanent magnets ... bearing portions 61, 62 ... bearing 70 ... outer stator 80 ... inner stator

Claims (3)

A shaft rotatably incorporated in the motor housing via a bearing portion, a rotor connected to rotate integrally with the shaft, and fixed to the housing so as to be located on the outer side in the rotational radial direction with respect to the rotor An outer stator, and an inner stator fixed to the housing so as to be positioned on the inner side in the rotational radius of the rotor, the rotor having a circumferential surface having a circular or regular polygonal cross section, and the rotor on the circumferential surface The through holes penetrating the inner and outer sides are arranged in the circumferential direction, flat plate permanent magnets are fitted into the respective through holes, the outer surfaces of the permanent magnets are arranged so as to face the outer stator, and the inner surfaces of the permanent magnets are arranged. In the double stator type motor arranged to face the inner stator,
The length dimension in the front-rear direction extending along the rotation center line of the rotor in the permanent magnet is set shorter than the length dimension in the front-rear direction extending along the rotation center line of the rotor in the through hole,
The upper and lower inner end surfaces perpendicular to the front-rear direction in the through hole are provided with a required taper so that the opening width of the through hole gradually increases or decreases along the rotation center line of the rotor,
A double stator type motor characterized in that the upper and lower end faces of the permanent magnet are in close contact with the upper and lower inner end faces of the through hole and the permanent magnet is fitted into the through hole.   2. The double stator according to claim 1, wherein a necessary taper is provided on both upper and lower inner end faces of the through hole so that an opening width of the through hole gradually increases or decreases along a rotational radius direction of the rotor. Type motor.   The double stator motor according to claim 2, wherein a required taper is provided on both upper and lower end faces of the through hole so that the opening width of the through hole gradually decreases toward the outer side in the rotational radius direction of the rotor. .

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