JP7329460B2 - Electric vehicle and its manufacturing method - Google Patents

Description

The present invention relates to an electric vehicle incorporating an in-wheel motor and a manufacturing method thereof.

Today, motor technology has advanced to include high-rpm motors, speed reducers and brakes inside the wheel. The higher the rotation, the more frictional heat is generated, requiring cooling power consumption to reduce the heat generated within the enclosed wheel. Patent Document 1 discloses such an in-wheel motor. Since the in-wheel motor is incorporated into various devices in the wheel, the parts are close to each other and the brake is included, so there is no place for heat to escape. Metal rolling bearings and gears, which are widely used, generate heat due to high rotation, so power consumption for cooling increases.

Japanese Patent No. 3440082

It is desired to reduce the number of bearings and gears of the rotating parts and provide a brake on the outside to reduce the heat generated by directly connecting the wheel and the rotor.

In order to achieve the above object, an electric vehicle according to the present invention includes an outer race to which a wheel is attached and an inner race facing the outer race, which are formed by sliding bearings, and the inner race is supported by a support frame of a suspension system. A stator that constitutes a motor is provided, while the outer race is provided with a rotor facing the stator of the inner race.

In this case, a brake device capable of clamping the brake disc to the outer race and the brake disc to the inner race outside the slide bearing is provided.
Furthermore, resin metal is provided on the sliding surfaces of the outer race and the inner race. The outer race may be provided with one or a plurality of depressions for positioning the resin metal, the resin metal may be provided with projections that fit in the plurality of depressions, and a circuit for escaping lubricating oil and air from the bottom of the depressions may be provided. .

Further, a drive motor having a speed reducer and an electromagnetic clutch may be assembled to the support frame, and the driving force may be transmitted to the support ring only when the vehicle is moving at a low speed or when moving backward by switching to the electromagnetic clutch.

In the method for manufacturing an electric vehicle according to the present invention, an outer race to which a wheel is attached and an inner race facing the outer race are formed by sliding bearings, and resin metal is provided on the sliding surfaces of the outer race and the inner race. A shim liner corresponding to an oil gap is sandwiched between the resin metal and the inner race, the outer race is assembled using the side race, and after the resin metal is cured, the resin metal is decomposed and the shim It is characterized by removing the liner and molding the specified oil gap.

According to the above configuration, since the wheel rotating mechanism has a sliding bearing structure in the present invention, the main rotating mechanism has no rolling bearings or other heat generating sources. Also, since the braking device is located outside the outer race, heat dissipation is performed here.

1 is a cross-sectional view of a tire mounting portion of an electric vehicle according to an embodiment of the present invention; FIG. 2 is an enlarged sectional view of FIG. 1; FIG. It is a sectional view of the tire attachment part of the electric vehicle concerning a 2nd embodiment. FIG. 11 is an enlarged cross-sectional view of the resin shaft metal, the cooling jacket for the inner race and the stator, and the partial tire mounting portion of the cooling circuit of the electric vehicle according to the third embodiment. It is a side race assembly drawing which forms the oil gap of the resin shaft metal.

Embodiments of the present invention will be described in detail below with reference to the drawings. It should be noted that the embodiments shown below are part of preferred modes for carrying out the present invention, and as long as the same effect is achieved, even if some of the configurations and methods are changed, the present invention can be applied. can be considered part of

1 and 2 show a cross-sectional view and a partially enlarged cross-sectional view of an in-wheel motor that constitutes an electric vehicle according to the present invention. As shown in these figures, it has a wheel 12 on which a tire 10 is mounted, and the wheel 12 is directly attached to a plain bearing 16 via a protrusion 14 provided at a position on the outer side of the inner peripheral surface.

The sliding bearing 16 is composed of a plurality of outer races 18 and inner races 20 , both of which slide via a stepped sliding surface 22 . The sliding surface 22 has a higher level difference on the vehicle body side so that the inner race 20 can be removed toward the vehicle body side. In order to prevent the sliding bearing 16 from swaying laterally, a side race 24 is attached to the minimum step portion on the inner race 20 side to suppress the maximum protrusion of the outer race 18 .

A doughnut-shaped support ring 26 is attached to the outer race 18 so as to cover the central opening of the tire 10 on the outside of the vehicle. The support ring 26 extends beyond the side surface of the inner race 20 to leave the radial center of the tire 10 open. The open end is bolted and covered with a flat plate cover 28 . A support frame 30 having an L-shaped cross section is attached to the inner race 20 inside the vehicle. The support frame 30 has an L-shaped tip portion attached to the outer surface portion of the inner race 20 and a bottom plate portion extending toward the center of the tire. The central portion is covered with a cover 32 and fixed with bolts. Further, the support frame 30 is supported by suspension devices 34 at two upper and lower positions.

A stator 36 constituting a part of the in-wheel motor is arranged at the corner portion of the support frame 30, and a rotor 38 arranged to face the stator 36 is arranged on the underside thereof. That is, since the stator 36 is fixed to the support frame 30, it functions as a stator frame. Also, the rotor 38 arranged facing each other is fixed to the support ring 26 attached to the outer race 18 via a pedestal 40 . As a result, when the rotor 38 receives a driving force, the tire 10 rotates via the pedestal 40, the support ring 26, and the outer race 18. At this time, the rotational driving force is generated by sliding on the inner race 20. transmitted.

In such an embodiment, furthermore, as shown in FIGS. 1 and 2, the end of the outer race 18 is extended and the brake disc 42 is assembled to the extended end. On the other hand, a brake device 44 capable of clamping this is attached to the support frame 30 located on the lower surface of the wheel. As a result, the electric vehicle can be provided with brakes that are in contact with the outside air.

As shown in FIG. 2, on the sliding surface 22 of the sliding bearing 16, the outer race 18 is provided with depressions 46 for positioning at a plurality of locations. A projection 50 that fits in is provided. A resin metal 48 having a low coefficient of friction is provided, and the resin metal 48 suppressing heat generation does not generate metal powder, so that the quality of lubricating oil can be maintained for a long period of time. At the bottom of the recess 46 of the outer race 18, a lubricating oil and air escape passage 52 is provided. An oil seal 54 is arranged between the outer race 18 and the inner race 20 .

In the electric vehicle according to the embodiment constructed as described above, the tire 10 can be rotated via the slide bearing 16, and the braking means are provided in the brake disc 42 provided at the extended end of the outer race 18 and the support frame 30. It is due to the brake device 44. Therefore, it is possible to simultaneously solve the noise problem associated with the gear mechanism and rolling bearings for driving the tire 10 and the cooling problem associated with the brake.

Next, FIG. 3 shows a second embodiment. In this embodiment, a drive motor 56 is attached to the central portion of the support frame 30, and thereby a speed reducer 58 and an electromagnetic clutch 60 are attached and held between the support ring 26 facing each other. On the other hand, a blower pipe 62 for cooling and a return pipe 64 are connected to two points of the support frame 30. By switching the operation, the drive force is transmitted to the support ring 26 and thus to the tire 10 only at low speed and during reverse movement. ing.
According to this embodiment, when the initial operation is heavy, the drive motor 56 is activated, and at the same time, the cooling air can be forcibly supplied.

FIG. 4 shows a third embodiment. This forms cooling jackets 66 at multiple locations on the support frame 30 . A cooling jacket 68 is also formed on the inner race 20 on the fixed side of the plain bearing 16 . Cooling oil can flow between the cooling jackets 66 and 68 through a communication passage 70, and the cooling jacket 68 of the inner race 20 is provided with a blowout port 72 leading to the sliding surface 22, so that the cooling oil can be supplied to the sliding surface. I'm trying
According to this embodiment, the sliding surface 22 of the sliding bearing 16, which tends to generate heat, can be always cooled by the cooling oil, so stable operation is possible.

FIG. 5 is an explanatory diagram of the fourth embodiment. A resin metal 48 having a low coefficient of friction is provided between the sliding surfaces 22 of the slide bearing 16. When the resin metal 48 is assembled, it is temporarily softened with a softening agent to correspond to the oil gap. The shim liner 74 is sandwiched between the inner race 20 and the resin metal 48 and between the side race 24 and the resin metal 48 . By assembling the outer race 18 with the side race 24, decomposing the resin metal 48 after it hardens, and removing the shim liner 74, it is possible to mold the specified oil gap.
By doing so, the method of assembling the resin metal 48 can be easily performed.

As described above, in the present invention, since the wheel rotation mechanism has a sliding bearing structure, the main rotation mechanism does not have rolling bearings or other heat generating sources. Also, since the braking device is located outside the outer race, heat dissipation is performed here.

The resin metal inserted between the outer race and the inner race has a low coefficient of friction, generates little heat, does not generate metal powder, and maintains the quality of the lubricating oil for a long period of time, making it possible to use the lubricating oil for cooling the stator.

The support frame of the stator becomes the size of the wheel, and the large-diameter rotor generates torque even at low speeds, eliminating the need for a reduction gear. Power consumption for cooling and a reduction in moving parts reduce the risk of failure.
The large-diameter brake disc, which is the size of the wheel, has a high braking effect and is easy to visually inspect.

10...Tire 12...Wheel 14...Protrusion 16...Sliding bearing 18...Outer race 20...Inner race 22...Sliding surface 24...Side race 26...Support Ring 28 Cover 30 Support frame 32 Cover 34 Suspension device 36 Stator 38 Rotor 40 Mounting base 42 Brake disc 44 Brake device 46 Recess 48 Resin metal 50 Protrusion 52 Air relief passage 54 Oil seal 56 Drive motor 58 Reducer 60 Electromagnetic Clutch 62 Blower pipe 64 Return pipe 66 Cooling jacket 68 Cooling jacket 70 Communication passage 72 Air outlet 74 Shim liner.

Claims (4)

An outer race to which the wheel is attached and an inner race facing the outer race are formed by slide bearings. A stator of the race and a rotor facing each other are provided, a resin metal is provided on the sliding surfaces of the outer race and the inner race, one or a plurality of depressions for positioning the resin metal are provided in the outer race, and the plurality of depressions are provided in the resin metal. An electric vehicle , comprising: a protrusion that fits in a recess; and a circuit through which lubricating oil and air escape from the bottom of the recess . 2. The electric vehicle according to claim 1, further comprising a brake device capable of clamping a brake disc to an outer race and an inner race to which the brake disc can be clamped. 2. The electric vehicle according to claim 1, wherein a drive motor having a speed reducer and an electromagnetic clutch is assembled to the support frame, and by switching to the electromagnetic clutch, driving force is transmitted to the support ring only when the vehicle is moving at a low speed or in reverse. An electric vehicle characterized by The outer race on which the wheel is mounted and the inner race facing the outer race are formed by sliding bearings, and when the resin metal is provided on the sliding surfaces of the outer race and the inner race, the resin metal is temporarily softened with a softener to fill the oil gap. A corresponding shim liner is sandwiched between the resin metal and the inner race, the outer race is assembled using the side race, the resin metal is decomposed after curing, the shim liner is removed, and the oil gap of the specified value is formed. A method of manufacturing an electric vehicle, characterized by:

Images