JP6822933B2 - Vehicle drive - Google Patents

Description

The present invention relates to a vehicle drive device for driving a vehicle by the power of an electric motor.

As a device of this type, conventionally, the electric motor is arranged below the seat of the vehicle with the rotation axis of the electric motor oriented in the vehicle height direction, and the torque of the electric motor is extended in the front-rear direction via a pair of umbrella gears. There is known a device that transmits to a propeller shaft (see, for example, Patent Document 1). In the device described in Patent Document 1, a bevel gear is provided at the upper end of a shaft fitted to the center of the rotor of the electric motor, and the bevel gear provided at the tip of the propeller shaft is meshed with the bevel gear. To.

Japanese Unexamined Patent Publication No. 2012-293369

However, in the device described in Patent Document 1, the power of the electric motor is transmitted to the propeller shaft via a pair of bevel gears. Therefore, for example, in order to decelerate the rotation of the electric motor with the propeller shaft, it is necessary to increase the diameter of the bevel gear of the propeller shaft. As a result, the vehicle drive device becomes larger in the height direction, and it is difficult to arrange the vehicle drive device in a predetermined space of the vehicle whose height direction is limited.

The vehicle drive device according to one aspect of the present invention includes an electric motor having a rotor that rotates about a first axis in the vertical direction and a stator arranged around the rotor, and extends along the first axis. , A first rotating shaft that has a first gear at the tip and rotates integrally with the rotor, and a second gear that is erected along the second axis on the side of the motor and meshes with the first gear at the tip. A second rotating shaft that is integrally provided with a worm that rotates around the second axis, a worm wheel that meshes with the worm and rotates around the third axis in the horizontal direction, an electric motor, and a first gear. A first case portion that forms a first oil chamber that surrounds the worm and the second gear, and a second case portion that forms a second oil chamber that surrounds the worm and the worm wheel are provided. The first oil chamber and the second oil chamber are sealed to each other so that different lubricating oils are supplied to the first oil chamber and the second oil chamber.

According to the present invention, a vehicle driving device for driving a vehicle by the power of an electric motor can be easily arranged in a predetermined space of the vehicle having a limited height direction.

The front view which shows the main part structure of the vehicle drive device which concerns on embodiment of this invention. FIG. 5 is a side view showing an example of mounting the vehicle drive device of FIG. 1 on a vehicle. Figure III of the arrow in FIG. FIG. IV of the arrow in FIG. The figure which shows the modification of FIG. The figure which shows the flow of the lubricating oil in the vehicle drive device of FIG. FIG. 5 is a cross-sectional view showing the configuration of the upper end portion of the second rotating shaft of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 7. FIG. 1 is a front view showing a main configuration of a vehicle drive device 100 according to an embodiment of the present invention. The vehicle drive device 100 has an electric motor 1 which is an example of a rotary electric machine, and outputs a traveling drive torque using the electric motor 1 as a drive source to the vehicle drive wheels. Therefore, the vehicle driving device 100 is mounted on a vehicle having an electric motor 1 as a traveling drive source, such as an electric vehicle or a hybrid vehicle. The electric motor 1 can also be used as a generator.

FIG. 2 is a side view showing an example of mounting the vehicle drive device 100 on a vehicle. Here, an example is shown in which the vehicle drive device 100 is arranged between the left and right front wheels 103 and used as the front wheel drive device. The vehicle drive device 100 can be arranged between the left and right rear wheels 104 and used as a rear wheel drive device.

As shown in FIG. 2, the vehicle driving device 100 is arranged near the bottom surface of the vehicle body and at the center of the vehicle in the left-right direction. As a result, the position of the hood of the vehicle can be lowered, and the superiority in terms of design and the like is enhanced. Further, although not shown, the vehicle drive device 100 can be easily arranged below the seat or between the left and right rear wheels 104 without raising the floor surface in the vehicle, that is, without sacrificing the riding space in the vehicle. This allows the vehicle drive device 100 to have a high degree of freedom in arrangement.

In the following, the vehicle drive device 100 is used in the front-rear direction (vehicle length direction), the vertical direction (vehicle height direction), and the left-right direction (vehicle width direction) of the vehicle when the vehicle drive device 100 is mounted on the vehicle. The configuration of each part will be described.

FIG. 3 is a view of arrow III of FIG. 1 (viewed from the front of the vehicle), and FIG. 4 is a view of arrow IV of FIG. 1 (viewed from below the vehicle). As shown in FIGS. 1, 3 and 4, the vehicle driving device 100 has an electric motor 1, a rotating body 2 arranged in front of the electric motor 1, and a rotating body 3 arranged further in front of the rotating body 2. .. That is, the vehicle driving device 100 has an electric motor 1, a rotating body 2, and a rotating body 3 arranged side by side in the front-rear direction.

The electric motor 1 has a rotor 11 that rotates about the vertical axis CL1 and a stator 12 that is arranged around the rotor 11. The electric motor 1 is, for example, an embedded magnet synchronous motor, and a plurality of permanent magnets in the circumferential direction are embedded in the rotor 11 (rotor core). A synchronous reluctance motor, a switch reluctance motor, or the like having no magnet can also be used as the electric motor 1.

The stator 12 has a substantially cylindrical stator core centered on the axis CL1 which is arranged from the outer peripheral surface of the rotor 11 (rotor core) via a gap having a predetermined radial length. The stator core is a stator core, and a plurality of slots in the circumferential direction are provided on the inner peripheral surface thereof in the radial direction, and windings (coils) are arranged in each slot by centralized winding or distributed winding. A rotating magnetic field is generated by passing a three-phase alternating current through the winding, and the rotor 11 rotates.

As shown in FIG. 4, a plurality (6) stator fixing portions 12a are provided on the outer peripheral surface of the stator 12 (stator core) at equal intervals in the circumferential direction. The stator fixing portion 12a is a flange portion protruding outward in the radial direction, and the stator 12 is fixed to the housing (FIG. 6) by bolts (not shown) that have passed through the vertical through holes of the stator fixing portion 12a. To. The figure in which the stator fixing portions 12a adjacent to each other in the circumferential direction are sequentially connected by a straight line becomes a regular hexagon as shown in the figure.

As shown in FIG. 1, a first rotating shaft 13 is arranged inside the electric motor 1 along the axis CL1. The first rotating shaft 13 is connected to the rotor 11 by, for example, spline coupling, and rotates integrally with the rotor 11. The upper end of the first rotating shaft 13 projects from the upper end surface of the rotor 11, and a first gear 14 having a diameter smaller than that of the rotor 11 is provided at the upper end of the rotor 11. The first gear 14 is connected to the first rotating shaft 13 by, for example, spline coupling, and rotates integrally with the first rotating shaft 13. The first gear 14 can also be machined on the outer peripheral surface of the first rotating shaft 13.

The first rotating shaft 13 is rotatably supported by a plurality of bearings BG1, BG2, BG3 (for example, tapered roller bearings) arranged apart from each other in the vertical direction. The upper bearings BG1 and BG2 are arranged on the upper side and the lower side of the first gear 14, respectively, and radial loads supporting both sides act on the bearings BG1 and BG2, respectively. This radial load changes according to the distance between the bearings BG1 and BG2 (bearing span L1), but the bearing span L1 is constant regardless of the vertical length (thickness) of the electric motor 1. Therefore, it is possible to suppress an increase in the radial load when the electric motor 1 has a flat shape centered on the vertical axis CL1.

On the other hand, for example, when the bearing BG1 is omitted and the first rotating shaft 13 is supported by the bearings BG2 and BG3, a cantilever radial load acts on the bearings BG2 and BG3. The radial load in this case increases as the distance between the bearings BG2 and BG3 becomes shorter. Therefore, when the electric motor 1 has a flat shape and the distance L2 between the bearings BG2 and BG3 becomes short, the radial load increases. In order to withstand such a radial load, it is necessary to increase the diameter and width of the bearings BG2 and BG3, and the bearings BG2 and BG3 become large.

The first gear 14 is composed of a bevel gear (more strictly, an oblique bevel gear). Since the first gear 14 is supported by the bearings BR1 and BR2 on both sides, the tooth streak load distribution coefficient can be reduced, whereby the number of modules can be reduced. Reducing the number of modules increases the front engagement rate, which can reduce the noise level. Considering the reduction of the radial load and the reduction of the noise level as described above, the first rotating shaft 13 can be supported at two upper and lower positions above the electric motor 1 (rotor 11) as in the present embodiment. preferable.

The rotating body 2 has a second rotating shaft 21 extending around the axis CL2. The axis CL2 is inclined at a predetermined inclination angle θ (for example, about 10 to 30 °) with respect to the vertical line, and the axes CL1 and CL2 intersect at an acute angle above the first gear 14. A second gear 22 is provided at the upper end of the second rotating shaft 21. The second gear 22 is connected to the second rotating shaft 21 by, for example, spline coupling, and rotates integrally with the second rotating shaft 21. The second gear 22 can also be machined on the outer peripheral surface of the second rotating shaft 21.

Like the first gear 14, the second gear 22 is composed of diagonal bevel gears, and the first gear 14 and the second gear 22 mesh with each other. The diameter of the second gear 22 is larger than the diameter of the first gear 14, and the first gear 14 and the second gear 22 mesh with each other above the rotor 11 (inner diameter side of the inner peripheral surface of the stator 12). By configuring the second gear 22 to have a diameter larger than that of the first gear 14, the reduction ratio can be increased, and the transmission torque from the first rotating shaft 13 to the rotating body 2 can be increased.

The second rotating shaft 21 is provided with a worm 23 constituting a worm gear below the second gear 22 and on the side of the electric motor 1. The worm 23 is a screw-shaped gear in which teeth are continuously formed in a spiral shape. The worm 23 is connected to the second rotating shaft 21 by, for example, a spline coupling, and rotates integrally with the second rotating shaft 21. It is also possible to process the worm 23 on the outer peripheral surface of the second rotating shaft 21. The second rotating shaft 21 is rotatably supported by a plurality of bearings BG4, BG5, BG6 (for example, tapered roller bearings) arranged apart from each other in the vertical direction. That is, the bearings BG4 and BG5 are arranged on the upper side and the lower side of the second gear 22, respectively, and the bearings BG5 and BG6 are arranged on the upper side and the lower side of the worm 23, respectively.

A worm wheel (oblique gear) 32 that can rotate around the axis CL3 in the left-right direction is meshed with the worm 23. The worm wheel 32 constitutes the rotating body 3 together with the third rotating shaft 31 extending along the axis CL3. The worm wheel 32 is connected to the third rotating shaft 31 by, for example, spline coupling, and rotates integrally with the third rotating shaft 31. The diameter of the worm wheel 32 is larger than the height of the electric motor 1. By increasing the diameter of the worm wheel 32 in this way, the reduction ratio can be increased, and the transmission torque from the rotating body 2 to the rotating body 3 can be increased.

As shown in FIG. 4, the axis CL2 of the second rotating shaft 21 is on a straight line (dotted line) L1 connecting the first axis CL1 and the midpoint P1 on one side of a regular hexagon formed by sequentially connecting the stator fixing portion 12a. The rotation axis CL3 of the worm wheel 32 is orthogonal to this straight line L1 in a plan view. As a result, the worm 23 can be arranged close to the electric motor 1, and the entire vehicle drive device 100 can be compactly configured.

As shown in FIG. 1, the maximum height of the vehicle driving device 100 is defined by a horizontal line H1 passing through an upper end portion (front end portion) of the second gear 22 inclined rearward. The power drive unit (PDU) 5 is arranged in the space above the first gear 14 (first rotating shaft 13) and below the horizon H1. The PDU 5 is a drive circuit including an inverter circuit, and the PDU 5 converts electric power from a battery (not shown) and supplies it to the coil of the stator 12.

FIG. 5 is a front view showing a schematic configuration of a vehicle drive device 101 as a modification of FIG. 1. The second axis CL2 in FIG. 5 extends in the vertical direction. Therefore, the first axis CL1 and the second axis CL2 are parallel to each other, and the first gear 14 and the second gear 22 are composed of, for example, spur gears. The sizes (diameters) of the first gear 14, the second gear 22, the worm 23, and the worm wheel 32 are the same as those of the vehicle drive device 100 of FIG. 1, respectively, and the vehicle drive device 100 is used by the vehicle drive device 101. A torque with a reduction ratio similar to that of the above can be obtained.

In FIG. 5, the alternate long and short dash line represents the horizontal line H1 that defines the maximum height of the second gear 22 of FIG. As shown in FIG. 5, when the PDU 5 is arranged above the first gear 14, the PDU 5 projects above the horizon H1. For this reason, the vehicle drive device 101 becomes larger in the height direction, and it may be difficult to arrange the vehicle drive device 101 in a limited space in the height direction of the vehicle. Considering this point, it is preferable to incline the second rotating shaft 21 with the upper end portion of the second rotating shaft 21 directed toward the axis CL1 as shown in FIG.

FIG. 6 is a diagram showing a flow of lubricating oil in the vehicle drive device 100 of FIG. As shown in FIG. 6, the housing 6 accommodating the electric motor 1 and the upper end portion of the first rotating shaft 13 and the upper end portion of the second rotating shaft 21, that is, the cover 7 accommodating the first gear 14 and the second gear 22. It has a case 8 for accommodating a worm 23 on the side of the electric motor and a worm wheel 32. The housing 6 and the cover 7 form a first oil chamber SP1, and the case 8 forms a second oil chamber SP2.

FIG. 7 is a cross-sectional view showing the configuration of the upper end portion of the second rotating shaft 21. As shown in FIG. 7, a partition wall 25 is arranged below the second gear 22 so as to face the second gear 22. A circular groove is provided on the outer peripheral surface of the second rotating shaft 21 facing the inner peripheral surface of the partition wall 25, and a substantially ring-shaped oil seal 9 is fitted in the groove. By providing the oil seal 9 on the outer peripheral surface of the second rotating shaft 21 in this way, the first oil chamber SP1 and the second oil chamber SP2 are sealed.

Lubricating oil is supplied to the first oil chamber SP1 by a hydraulic pump (not shown). As shown in FIG. 6, the lubricating oil supplied to the first oil chamber SP1 passes through the first gear 14 and the second gear 22 as shown by the arrow A1, and then is along the stator 12 of the electric motor 1 by gravity. Flow. As a result, the first gear 14 and the second gear 22 can be lubricated, and the stator 12 (coil) can be cooled. As the lubricating oil supplied to the first oil chamber SP1, ordinary ATF oil is used.

Lubricating oil collects at the bottom of the second oil chamber SP2. As shown by the arrow A2 in FIG. 6, the accumulated lubricating oil is scraped up by the rotation of the worm wheel 32, and the worm gear including the worm 23 and the worm wheel 32 is lubricated. Since the worm gear has a large slip on the tooth surface, an oil having an extreme pressure agent mixed in and having a higher viscosity than ordinary ATF oil is used as the lubricating oil supplied to the second oil chamber SP2.

According to this embodiment, the following effects can be obtained.
(1) The vehicle drive devices 100 and 101 extend along the axis CL1 and the electric motor 1 having the rotor 11 rotating around the axis CL1 in the vertical direction and the stator 12 arranged around the rotor 11. The first gear 14 is provided at the tip, and the first rotating shaft 13 that rotates integrally with the rotor 11 and the first gear 14 are erected on the side of the electric motor 1 along the axis CL2. A worm wheel that has a second gear 22 that meshes and is integrally provided with a worm 23 that rotates about the axis CL2 and a worm wheel that meshes with the worm 23 and rotates about the horizontal axis CL3. 32 and (FIGS. 1 and 5).

With this configuration, the torque of the electric motor 1 that rotates around the vertical axis CL1 without increasing the size of the vehicle drive devices 100 and 101 in the height direction can be obtained in the third rotation in the horizontal direction while obtaining a sufficient reduction ratio. It can be transmitted to the shaft 31. Therefore, as shown in FIG. 2, the vehicle drive devices 100 and 101 can be easily arranged in a predetermined space of the vehicle whose height direction is limited. That is, for example, when the second rotating shaft 21 extends in the horizontal direction, the vehicle driving device becomes larger in the height direction when a large-diameter gear is provided at the tip of the second rotating shaft 21. On the other hand, as in the present embodiment, the second rotating shaft 21 is erected on the side of the electric motor 1, and the torque is transmitted to the third rotating shaft 31 via the worm 23. Even if the second gear 22 having a large diameter is provided at the tip of the two rotating shafts 21, the height of the vehicle driving device 100 can be suppressed.

(2) The first gear 14 and the second gear 22 are oblique bevel gears, respectively, and the axis CL1 and the axis CL2 intersect at an acute angle (FIG. 1). By inclining the axis CL2 with respect to the vertical axis CL1 in this way, the large-diameter worm wheel 32 can be arranged below the second gear 22 without increasing the size of the vehicle drive device 100 in the height direction. Can be done.

(3) The vehicle drive device 100 is arranged between the tip of the first gear 14 in the height direction and the horizontal line H1 passing through the upper end of the second gear 22, and further adds a PDU 5 for supplying driving power to the electric motor 1. Prepare (Fig. 1). As a result, the PDU 5 can be efficiently arranged in the surplus space created by tilting the second rotation shaft 21. In this case, in order to suppress the height of the horizon H1, it is preferable that the inclination angle θ (FIG. 1) of the axis CL2 is small. For example, the inclination angle θ is set to a minimum angle at which the PDU 5 can be arranged below the horizon H1 and the worm wheel 32 can be arranged below the second gear 22.

(4) The vehicle drive device is arranged on both sides of the first gear 14 in the axial direction and is arranged on both sides of the second gear 22 in the axial direction with a pair of bearings BG2 and BG2 that rotatably support the first gear 14. It further includes a pair of bearings BG4 and BG5 that rotatably support the second gear 22. As a result, it is possible to suppress an increase in the radial load when the electric motor 1 is thinned in the height direction, and it is possible to reduce the noise level.

(5) The vehicle drive device 100 surrounds the housing 6 and the cover 7 forming the first oil chamber SP1 surrounding the electric motor 1, the first gear 14, and the second gear 22, and the worm 23 and the worm wheel 32. A case 8 for forming the second oil chamber SP2 is further provided (FIG. 6). The first oil chamber SP1 and the second oil chamber SP2 are sealed with each other by an oil seal 9, and different lubricating oils are supplied to the first oil chamber SP1 and the second oil chamber SP2. Specifically, ordinary ATF oil is supplied to the first oil chamber SP1, and highly viscous oil mixed with an extreme pressure agent is supplied to the second oil chamber SP2. As a result, it is possible to supply the optimum lubricating oil to each part of the vehicle drive device 100 according to the application.

In the above embodiment, the axis CL2 (second axis) of the second rotation axis 21 is inclined with respect to the axis CL1 (first axis) of the first rotation axis 13 at a predetermined inclination angle θ. The inclination angle θ may be any as long as it is erected on the side of 1. In order for the second rotating shaft 21 to be erected, the inclination angle θ needs to be at least 45 ° or less. In this respect, the inclination angle θ is preferably, for example, an angle smaller than 30 °, and more preferably an angle smaller than 15 ° from the viewpoint of suppressing the height of the vehicle driving device. As shown in FIG. 5, the second rotating shaft 21 may be erected without being tilted. The arrangement of the vehicle driving device 100 is not limited to that described above, and for example, the axis CL3 (third axis) of the third rotating shaft 31 may be aligned with the axis of the driving wheels (front wheels 103 or rear wheels 104) of the vehicle.

In the above embodiment, the tapered roller bearings BG1 and BG2 (first bearing, second bearing) are arranged on both the upper and lower sides of the first gear 14, and the tapered roller bearings BG4 and BG5 (third) are arranged on both the upper and lower sides of the second gear 22. The bearing and the fourth bearing) are arranged, but the configuration of the bearings BG1, BG2, BG3, and BG4 that receive the radial load is not limited to this. For example, ball bearings may be used. In the above embodiment, the housing 6 and the cover 7 form the first oil chamber SP1 and the case 8 forms the second oil chamber SP2, but the first case portion forming the first oil chamber The configuration of the second case portion forming the second oil chamber is not limited to this.

In the above embodiment, the first gear 14 is arranged above the electric motor 1, but the first gear may be arranged below the electric motor 1. In this case, a second gear may be provided at the lower end of the second rotating shaft 21 so as to mesh with the first gear.

The above description is merely an example, and the present invention is not limited to the above-described embodiments and modifications as long as the features of the present invention are not impaired. It is also possible to arbitrarily combine one or a plurality of the above-described embodiments and the modified examples, and it is also possible to combine the modified examples.

1 Electric motor, 11 rotor, 12 stator, 13 1st rotating shaft, 14 1st gear, 21 2nd rotating shaft, 22 2nd gear, 23 worms, 32 worm wheels, 100, 101 vehicle drive unit, 5 power drive unit, CL1 ~ CL3 axis line, H1 horizontal line, BG1, BG2, BG4, BG5 bearing, SP1 1st oil chamber, SP2 2nd oil chamber

Claims (4)

An electric motor having a rotor that rotates about a first axis in the vertical direction and a stator arranged around the rotor.
A first rotating shaft that extends along the first axis, has a first gear at the tip, and rotates integrally with the rotor.
A second gear that is erected on the side of the electric motor along the second axis, has a second gear that meshes with the first gear at the tip, and is integrally provided with a worm that rotates about the second axis. 2 rotation axes and
A worm wheel that meshes with the worm and rotates about the third horizontal axis.
A first case portion that forms a first oil chamber that surrounds the electric motor, the first gear, and the second gear.
A second case portion that forms a second oil chamber that surrounds the worm and the worm wheel is provided .
A vehicle driving device, characterized in that the first oil chamber and the second oil chamber are sealed to each other so that different lubricating oils are supplied to the first oil chamber and the second oil chamber . In the vehicle drive device according to claim 1,
The first gear and the second gear are oblique bevel gears, respectively, and the vehicle driving device is characterized in that the first axis and the second axis intersect at an acute angle. In the vehicle drive device according to claim 2.
It is further provided with a power drive unit that is arranged between the height-wise tip of the first gear and the horizontal line that passes through the height-direction end of the second gear and supplies driving power to the electric motor. Vehicle drive. In the vehicle drive device according to any one of claims 1 to 3.
The first bearing and the second bearing which are arranged on both sides in the axial direction of the first gear and rotatably support the first gear, and the second gear which is arranged on both sides in the axial direction of the second gear and can rotate the second gear. A vehicle drive device further comprising a third bearing and a fourth bearing that support the vehicle.

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