JP2007182194A - In-wheel motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent dust and water drops from intruding to the inside of an in-wheel motor. <P>SOLUTION: The in-wheel motor is arranged in a wheel 12 of a wheel 10 attached to a vehicle. An inner case 46 of a hollow shape is supported by the wheel through a suspension device. A stator 35 is fitted to an outer periphery of the inner case 46. A cylindrical outer case 40 is fixed to a rotatably supported hub 14 and is positioned on the outer periphery of the inner case 46. A permanent magnet 42 is fitted to an inner periphery of the outer case 40 through a gap so as to be opposed to the stator 35 to constitute a rotor. The outer peripheries of the stator and the rotor are covered by an inner case cover 38 and an outer case cover 44, respectively. A labyrinth structure 48 is formed by the inner case 46 and the outer case 40 on a portion communicating with a gap between the rotor and the stator. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an in-wheel motor, and more particularly to a technique for improving dustproof performance in a direct drive in-wheel motor.

Conventionally, an in-wheel motor type vehicle capable of independently controlling the braking / driving force of each wheel is known. In an in-wheel motor, since a motor is arrange | positioned inside the wheel which drive | works on a road surface, prevention of the penetration | invasion of the foreign material and a water | moisture content into a motor inside becomes a subject. Patent Document 1 discloses an in-wheel motor system including a waterproof mechanism that prevents water from entering the inside of the in-wheel motor. According to the present invention, the space inside the in-wheel motor and the air pump are connected by the pipe, and the pressure inside the motor is pressurized by the pump to prevent water from entering.
JP 2005-153724 A

  However, in the above-mentioned Patent Document 1, since a configuration such as an air pump and a pressure adjustment valve is required on the vehicle body side, there is a problem that vehicle weight and cost increase.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique for preventing a decrease in motor performance due to intrusion of foreign matter or water droplets into the in-wheel motor with a simple configuration.

  An aspect of the present invention is an in-wheel motor arranged in a wheel of a wheel mounted on a vehicle, and is fitted into a hollow inner case supported by the vehicle via a suspension device and an outer periphery of the inner case Of the outer case, a hub supported rotatably with respect to the inner case, a cylindrical outer case fixed to the hub and positioned on the outer periphery of the inner case, and the outer case so as to face the stator via a gap A rotor fitted into the inner periphery, an inner cover that covers the outer periphery of the stator, and an outer cover that covers the inner periphery of the rotor.

  According to this aspect, even if dust or water droplets enter the inside of the motor, it does not directly adhere to the iron core or magnet of the stator, so that it is possible to suppress a reduction in performance of the motor.

  A labyrinth structure may be formed in a portion leading to the gap between the rotor and the stator by the inner case and the outer case. As a result, the amount of dust and water droplets entering the gap can be greatly reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the fall of the motor performance by the penetration | invasion of the foreign material and water drop to the inside of an in-wheel motor can be prevented.

  One embodiment of the present invention relates to a dust-proof structure of a direct drive in-wheel motor that is arranged in a wheel of a driving wheel of a vehicle and can generate a large torque without using a reduction gear.

  FIG. 1 shows a cross-sectional structure of a wheel 10 including an in-wheel motor according to the present embodiment. A tire 50 is mounted on the wheel rim of the wheel 12. A hollow inner case 46 connected to the suspension arm of the vehicle is disposed on the inner peripheral side of the wheel 12. The suspension arm is connected to a vehicle (not shown) via a suspension device such as a coil spring or absorber (not shown), and supports the wheel 10 including an in-wheel motor.

  The inner case 46 includes a flange portion 46a and a cylindrical portion 46b that extends to the right in FIG. On the outer periphery of the cylindrical portion 46b, an iron core 36 formed of laminated electromagnetic steel plates, and a coil 34 wound around a three-phase coil slot wound around each tooth portion formed on the iron core 36, The stator 35 comprised from this is inserted.

  A bearing 45 is mounted on the outer side of the cylindrical portion 46b, that is, on the right side of FIG. The bearing 45 includes an outer race 28, a hub 14 also serving as an inner race 14a, a bearing ball 22 that rolls in a rolling groove formed in the outer race 28 and the inner race 14a, and foreign matter in the rolling groove. And seals 24 and 26 for preventing intrusion. The outer race 28 is fixed to the inner case 46 by a protrusion 46 c formed on the inner case 46 and a retaining ring 30. In the present embodiment, the load is distributed by arranging the bearing balls 22 in two rows. The hub 14 is rotatably supported by the bearing 45 with respect to the inner case 46.

  The hub 14 has a flange portion 14b that is bent in the L-shaped cross section from the inner race 14a portion toward the outer periphery of the wheel, and the wheel 12 with the tire 50 attached thereto is fixed to the flange portion 14b by a hub bolt 16. . A brake disc 32 is sandwiched between the wheel 12 and the hub 14 and fixed by bolts 18.

  A cylindrical outer case 40 is fixed to the outermost periphery of the flange portion 14 b of the hub 14 with bolts 20. The outer case 40 extends toward the vehicle inner side to a position reaching the flange portion 46a of the inner case 46. A plurality of permanent magnets 42 are fitted on the inner periphery of the outer case 40 so as to face the iron core 36 of the stator 35 via a predetermined gap. The outer case 40 and the permanent magnet 42 form an outer rotor located on the outer peripheral side of the stator. With the above configuration, by sequentially supplying current to the coil 34 at a predetermined timing, a rotating magnetic field can be generated in the stator 35 and the rotor can be rotated.

  The inner case 46 and the outer case 40 are manufactured by, for example, aluminum die casting in consideration of reduction in unsprung weight of a suspension (not shown), durability, ease of manufacturing, and the like.

  While the inner case 46 and the stator 35 are fixed by a suspension arm, the outer case 40, the permanent magnet 42, the wheel 12, the hub 14, and the brake disk 32 are rotatably supported. When the in-wheel motor is driven by a command from a vehicle control device (not shown), the rotor rotates with respect to the stator 35, the output is transmitted to the wheel 12 through the outer case 40, and the wheel 10 is rotationally driven. .

  Such an in-wheel motor can omit transmission system parts and installation space, and can eliminate loss due to transmission, as compared with a system that distributes the output of a single motor to each wheel. There are features. In addition, since the direct drive in-wheel motor does not require a speed reduction mechanism, the structure is simple and the weight of the wheel can be reduced.

  In the present embodiment, a thin inner case cover 38 is attached to the inner case 46 so as to cover and seal the outer periphery of the stator 35. A thin outer case cover 44 is attached to the outer case 40 so as to cover the permanent magnet 42 on the inner peripheral side of the rotor. The material of these covers is preferably a non-magnetic material such as plastic so as not to prevent the passage of magnetic flux. These covers 38 and 44 prevent dust and water droplets entering from the outside of the wheel from directly attaching to the stator 35 and the permanent magnet 42.

  The vehicle inner side of the outer case 40, that is, the left end has a small diameter portion 40a that is stepped so that the outer diameter decreases. A step-like labyrinth structure 48 is formed in the circumferential direction by the small diameter portion 40 a and the flange portion 46 a of the inner case 46. The labyrinth structure 48 makes it difficult for dust and water droplets to enter the gap between the stator and the rotor.

Thus, the in-wheel motor of this embodiment prevents intrusion of dust and water droplets into the gap portion by forming a labyrinth structure with the outer case and the inner case. Therefore, there is no need to provide a seal between the outer case and the inner case.
In general, the outer rotor type in-wheel motor has a problem in that dust and water droplets easily enter because the rotor and the stator have large diameters and the cross-sectional area of the space that should be prevented from entering by the seal increases. In addition, the direct drive type in-wheel motor has a problem that the circumferential speed of the lip portion of the seal is larger than that of a motor that is not direct drive, and the lip portion is easily worn. In this embodiment, since the labyrinth structure is adopted instead of the seal, such a problem does not occur. Moreover, dustproof performance can be secured without a special device such as sending air into the gap.

  In the in-wheel motor according to the present embodiment, the rotor and the stator are covered with a thin cover. Although it is difficult to completely prevent the intrusion of dust and water droplets with the labyrinth structure alone, even if they intrude, they do not adhere directly to the stator core and magnets, thus suppressing the motor performance degradation. Can do. As described above, in the present embodiment, by providing a cover that covers the stator and the rotor, a small amount of foreign matter can be allowed to enter the gap, so that the seal for dust-proofing the gap can be eliminated.

  In addition, by sealing the stator 35 with the inner case cover, it is possible to circulate oil inside the cover and cool the stator.

In the present embodiment, the bearing 45 is disposed on the inner peripheral side of the inner case 46, and the outer case 40 is fixed to the hub 14 that is rotatably supported by the bearing 45. With such a bearing arrangement, the outer diameters of the outer race 28 and the inner race 14a of the bearing 45 can be reduced. Therefore, since the diameters of the seals 24 and 26 can be reduced, the sealing performance can be improved. Furthermore, since the bearing diameter is reduced, the rigidity of the outer race 28 and the inner race 14a can be ensured.
By making the cylindrical portion 46b of the inner case 46 thick, the diameter of the bearing 45 can be further reduced.

  The present invention has been described based on the embodiments. These embodiments are merely examples, and those skilled in the art understand that modifications such as arbitrary combinations of the embodiments and arbitrary combinations of the components of the embodiments are also within the scope of the present invention. It is where it is done.

  Since the adhesion of foreign matter to the permanent magnet 42 has less influence than the adhesion of foreign matter to the iron core 36, the outer case cover 44 on the rotor side need not be provided. Thereby, a gap can be made small and the output performance of a motor can be improved.

  Instead of providing the inner case cover 38 and the outer case cover 44, the coil 34, the iron core 36, and the permanent magnet 42 of the stator 35 may be covered with a resin mold.

  A labyrinth structure may also be provided at the right end of the rotor and stator, that is, the side facing the hub 14.

It is a figure showing the section structure of the inner wheel motor concerning one embodiment of the present invention.

Explanation of symbols

  10 wheels, 12 wheels, 14 hubs, 16 hub bolts, 18 bolts, 20 bolts, 22 bearing balls, 24, 26 seals, 28 outer races, 30 retaining rings, 32 brake discs, 34 coils, 35 stators, 36 iron cores, 38 inners Case cover, 40 outer case, 42 permanent magnet, 44 outer case cover, 45 bearing, 46 inner case, 48 labyrinth structure, 50 tires.

Claims (2)

An in-wheel motor disposed in a wheel of a wheel mounted on a vehicle,
A hollow inner case supported by the vehicle via a suspension device;
A stator that is inserted into the outer periphery of the inner case;
A hub that is rotatably supported with respect to the inner case;
A cylindrical outer case fixed to the hub and positioned on the outer periphery of the inner case;
A rotor fitted into the inner periphery of the outer case so as to face the stator via a gap;
An inner cover covering the outer periphery of the stator;
An outer cover covering the inner periphery of the rotor;
An in-wheel motor comprising:   The in-wheel motor according to claim 1, wherein a labyrinth structure is formed in a portion leading to a gap between the rotor and the stator by the inner case and the outer case.

Images