JP4730664B2 - In-wheel motor - Google Patents

Description

  The present invention relates to an in-wheel motor that is incorporated in a wheel of a vehicle and directly drives a driving wheel to rotate.

  As one type of in-wheel motor, Japanese Patent No. 3515628 incorporates a rotor into a motor housing via a rotor bearing so that the rotor can be rotated, and the stator is fixed to the motor housing so as to be located on the outer side in the rotational radius of the rotor. Describes an in-wheel motor in which a motor shaft is serrated.

  In this in-wheel motor, a wheel shaft is rotatably incorporated in a motor housing via a wheel shaft bearing, and the motor shaft and the wheel shaft are connected in transmission via a reduction mechanism. A wheel and a brake drum are connected to the wheel shaft.

  In the above-described conventional in-wheel motor, a speed reduction mechanism is interposed between a motor shaft that rotates at a high speed integrally with the rotor and a wheel shaft to which a wheel and a brake drum are connected in order to generate a required high torque. Therefore, an increase in size and complexity of the motor is inevitable.

  In addition, since the speed reduction mechanism needs to enclose oil for cooling and lubrication and requires an oil circulation structure, the structure of the motor is further complicated.

Furthermore, a rotor bearing that rotatably supports the rotor and a wheel shaft bearing that rotatably supports the wheel shaft are required. Therefore, not only the structure is further complicated, but also the rotor and the wheel shaft are supported by separate bearings, so that vibration and noise are likely to occur.
Japanese Patent No. 3515628

  In view of the above problems, it is a first object of the present invention to provide a small and high output in-wheel motor. A second object is to provide an in-wheel motor with less vibration noise.

  In order to achieve the above object, an invention according to claim 1 includes a motor housing suspended from a vehicle body, and a wheel shaft rotatably incorporated in the motor housing via a bearing portion and connected to a wheel at one end. An in-wheel motor that is incorporated inside a wheel and drives the wheel, the rotor being coupled to the wheel shaft so as to rotate integrally with the wheel shaft, and the rotor being located radially outward with respect to the rotor An outer stator fixed to the housing, 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.

  According to a second aspect of the present invention, in the in-wheel motor according to the first aspect, the motor housing is fixed to the outer housing so as to cover the outer housing having the inner end surface opened and the inner end surface opening of the outer housing. It is comprised from the inner housing, The said bearing part was integrally provided in either one of the said outer housing or an inner housing, It is characterized by the above-mentioned.

The invention described in claim 3 in-wheel motor according to claim 2, connecting the suspension system of a vehicle to the inner housing, the bearing unit, characterized in that provided in the inner housing.

  The in-wheel motor according to claim 4 is the in-wheel motor according to claim 2 or 3, wherein a cylindrical shaft portion is formed integrally with the rotor, and the wheel shaft is inserted into the cylindrical shaft portion so that the rotor and the wheel are inserted. A shaft is integrally coupled, and the rotor is supported by the bearing portion.

  According to the first aspect of the present invention, since the double stator structure including the outer stator and the inner stator is adopted as the stator, even if the wheel shaft and the rotor are directly connected so as to rotate integrally without providing a speed reduction mechanism, the required structure is obtained. High torque can be obtained. Therefore, the reduction mechanism can be eliminated, and the motor can be miniaturized and the structure can be simplified.

  According to the second aspect of the present invention, since the bearing portion that supports the motor shaft is provided in one of the outer housing and the inner housing constituting the motor housing, the bearing portion is provided in the outer housing and the inner housing. The support is more stable than the case where it is provided across both. Therefore, vibration and noise can be suppressed.

  According to the third aspect of the present invention, since the bearing portion is provided in the inner housing and the suspension device is connected to the inner housing, the structure is simplified and the productivity is improved.

  According to the fourth aspect of the present invention, since the rotor and the wheel shaft are supported by the common bearing portion, the support structure of the rotor and the wheel shaft is simplified, and the generation of vibration and noise can be further suppressed.

  The present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view showing an in-wheel motor according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view showing a main part of the in-wheel motor. The in-wheel 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. FIG. 2 shows the external shape of the rotor. The rotor 50 includes a rotor main body 53 in which a disc-shaped rotor shaft 51 and a cylindrical shaft portion 52 are integrally formed, a rotor core 54 made of a laminate of ring-shaped thin steel plates, a ring-shaped rotor core presser 55, a rotor backup ring 56, a rotor stat bolt. 57, an outer permanent magnet 58 and an inner permanent magnet 59 are provided. Then, the rotor core holder 55, the rotor core 54, and the rotor backup ring 56 are attached in this order to the outer peripheral edge portion of the rotor shaft 51 by the rotor stat bolt 57, so that a large number of thin steel plates are integrally held to form the peripheral wall of the rotor core 54. Yes. A plurality of fitting holes are formed in the rotor core 54 along the circumferential direction, and an outer permanent magnet 58 is fitted into each fitting hole. Further, the inner permanent magnet 59 is attached to the inner peripheral surface of the rotor core at a position facing each outer permanent magnet 59.

  In FIG. 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 63 a is integrally formed at one end, and the flange portion 63 a of the bearing case 63 is a bolt 64 and the inner housing 22. It 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 52 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 attached to the cylindrical shaft portion 52 and the fine nut 67 is tightened to prevent the ball bearings 61 and 62 from coming off from the cylindrical shaft portion 52.

  The wheel shaft 30 is inserted into the cylindrical shaft portion 52 of the rotor 50 rotatably incorporated in the housing 20 by the bearing portion 60, and the serrated coupling 30a is formed so that the cylindrical shaft portion 52 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. Thus, both bearings 61 and 62 constituting the bearing portion 60 are arranged at predetermined positions so that the axial center of gravity of the rotor 50 and the center of gravity of the wheel shaft 30 are positioned between both bearings 61.62.

  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. Thus, the outer stator 70 is disposed and fixed on the inner peripheral surface of the outer housing 21 so as to be positioned outside the rotational radius of the rotor 50, that is, close to the outside of the outer magnet 58.

  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. . In this way, the inner stator 80 is disposed and fixed to the inner housing 22 via the bearing case 63 so as to be positioned on the inner side of the rotor in the radial direction of rotation, that is, closer to the inner side of the inner magnet 59.

  The end on the side opposite to the hub of the wheel shaft 30 passes through the cylindrical shaft portion 52 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 in-wheel motor 10 according to the present embodiment is as described above. Since the double stator structure including the outer stator 70 and the inner stator 80 is adopted, the wheel shaft 30 and the rotor 50 are integrated without providing a speed reduction mechanism. Even if it is directly connected so as to rotate, the required high torque can be obtained. Therefore, the reduction mechanism can be eliminated, and the motor can be miniaturized and the structure can be simplified.

  Further, in the in-wheel motor 10 according to the present embodiment, the bearing portion 60 that supports the motor shaft 30 is provided only in the inner housing of the outer housing 21 and the inner housing 22 constituting the motor housing 20, so the bearing portion 60 is disposed in the outer housing 21. The support is more stable than the case where it is provided across both the housing 21 and the inner housing 22. Therefore, vibration and noise can be suppressed.

  In addition, since the inner housing 22i bearing portion is provided and the suspension device is connected to the inner housing 22, the structure is simplified and the productivity is improved.

  Furthermore, since the rotor 50 and the wheel shaft 30 are supported by the common bearing portion 60, the structure can be further simplified, and the generation of vibration and noise can be suppressed.

  Furthermore, not only the heat generated in the outer housing 70 is conducted to the outer housing 21 and radiated from the housing 20 to the outside, but the heat from the inner stator 80 is also conducted to the inner housing 22 via the bearing case 63, so The heat is dissipated. For this reason, since it is not necessary to enclose cooling oil in the motor, the structure can be further simplified.

  In addition, since the wheel shaft 30 penetrates the housing 20 and both end portions can protrude to the outside of the housing 20, the brake drum 90 is not only on the inside in the vehicle width direction but also on the outside as seen in the present embodiment. Arrangement is also possible, increasing the degree of freedom of design.

  If the rotor core 54 is made of a non-magnetic material with the rotor stud bolt 57, the rotor core 55 presser, and the rotor backup ring 56 in this embodiment made of a magnetic material, the motor output is further increased by the principle of a squirrel-cage induction motor. be able to.

  In the present embodiment, the bearing portion 60 and the inner housing 22 are separated from each other, but may be integrated. In addition, various embodiments such as forming the rotor 50 and the cylindrical shaft portion 51 separately and joining them can be considered.

It is sectional drawing which shows the in-wheel motor which concerns on one Example of this invention. It is a disassembled perspective view which shows the principal part of the same in-wheel motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... In-wheel motor 20 ... Housing 21 ... Outer housing 22 ... Inner housing 30 ... Wheel shaft 40 ... Wheel 50 ... Rotor 51 ... Cylindrical shaft part 60 ... Bearing part 61, 62 ... Bearing 70 ... Outer stator 80 ... Inner stator

Claims (4)

An in-wheel motor that includes a motor housing suspended on a vehicle body and a wheel shaft that is rotatably incorporated in the motor housing via a bearing portion and that is connected to a wheel at one end, and that is incorporated inside the wheel to drive the wheel. A rotor coupled to the wheel shaft so as to rotate integrally with the wheel shaft, an outer stator fixed to the housing so as to be located on the outer side in the rotational radial direction with respect to the rotor, and rotation relative to the rotor An in-wheel motor comprising: an inner stator fixed to the housing so as to be located radially inside. The motor housing is composed of an outer housing having an inner end surface opened, and an inner housing fixed to the outer housing so as to cover the inner end surface opening of the outer housing, and the bearing portion is either the outer housing or the inner housing. The in-wheel motor according to claim 1, wherein the in-wheel motor is integrally provided on one side. In-wheel motor according to claim 2, wherein the connecting the suspension system of a vehicle to the inner housing, the bearing unit, characterized in that provided in the inner housing. The cylindrical shaft portion is integrally formed with the rotor, the wheel shaft is inserted into the cylindrical shaft portion, the rotor and the wheel shaft are integrally coupled, and the rotor is supported by the bearing portion. The in-wheel motor according to 2 or 3.

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