Vehicular drive unit

Abstract

A drive unit is provided for driving a wheel installed on a vehicle. The drive unit includes a driving source equipped with a rotary shaft. A speed reducer is connected between the driving source and the wheel so as to reduce the rotational speed of the rotary shaft and transmit the reduced rotational speed to the wheel. A brake unit is provided having a rotary member rotationally connected to the speed reducer on a side of the speed reducer opposite from the wheel so as to brake the rotation of the wheel through the speed reducer.

Description

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a partial cross-sectional view (along a radial plane) of a drive unit according to a first alternative embodiment of the invention, taken along a radial plane extending from the axis of rotation of the wheel and drive unit and outward in a radial direction toward the wheel rim.

FIG. 2 is a partial cross-sectional view (along a radial plane) of an embodiment in which the drive unit in FIG. 1 is applied to an outer race type drive unit.

FIG. 3 is a partial cross-sectional view (along a radial plane) for explaining an example in which the drive unit in FIG. 1 is applied to an inner/outer race type drive unit.

FIG. 4 is a partial cross-sectional view (along a radial plane) for explaining a drive unit pertaining to the second embodiment of the present invention.

FIG. 5 is a partial cross-sectional view (along a radial plane) for explaining an example in which the drive unit in FIG. 4 is applied to the outer race type drive unit.

FIG. 6 is a partial cross-sectional view (along a radial plane) for explaining an example in which the drive unit in FIG. 4 is applied to the inner/outer race type drive unit.

FIG. 7 is a partial cross-sectional view (along a radial plane) for explaining a drive unit pertaining to the third embodiment of the present invention.

FIG. 8 is a partial cross-sectional view (along a radial plane) for explaining an example in which the drive unit in FIG. 7 is applied to the outer race type drive unit.

FIG. 9 is a partial cross-sectional view (along a radial plane) according an embodiment the drive unit in FIG. 7 applied to the inner/outer race type drive unit.

FIG. 10 is a cross-sectional view taken along a plane drawn diametrically through the axis of rotation of the drive unit according to a fourth embodiment of the present invention.

FIGS. 11 a and b show cross sectional view of a drive unit according to a fifth alternative embodiment of the present invention; wherein, FIG. 11(a) is an overall explanatory diagram, and FIG. (b) is an enlarged partial view of selected portion of FIG. 11(a).

Claims

1. A drive unit for driving a wheel installed on a vehicle, the drive unit comprising: a driving source equipped with a rotary shaft,a speed reducer connected between the driving source and the wheel so as to reduce the rotational speed of the rotary shaft and transmit the reduced rotational speed to the wheel, anda brake unit having a rotary member rotationally connected to the speed reducer on a side of the speed reducer opposite from the wheel so as to brake the rotation of the wheel through the speed reducer.

2. The drive unit of claim 1, wherein the driving source comprises a motor generator and the rotary shaft comprises a motor rotary shaft.

3. The drive unit of claim 1, wherein the rotary shaft of the driving source is provided coaxially with the wheel.

4. The drive unit of claim 1, wherein the speed reducer of the drive unit comprises a sun gear, a planet pinion, a ring gear, and a carrier; the sun gear is integrally formed as one body with an end part of the rotary shaft of the driving source;the planet pinion is provided on the outer circumference of the sun gear, engages the sun gear, and rotates on a planet pinion axis as the sun gear rotates;the ring gear is fixed to a case which supports the carrier in a freely rotatable fashion, and allows the planet pinion to orbit as an inner circumferential surface of the ring gear and an outer circumferential surface of the planet pinion engage each other; andthe carrier supporting the orbiting planet pinion and coaxially linked to the wheel.

5. The drive unit of claim 4, further comprising: a hub formed at a front end part of the carrier and linked to the wheel,a bearing for rotatably supporting the carrier from the hub for free rotation on the hub,a case that covers the speed reducer and the driving source with a lubricating oil to provide the lubricating oil to lubricate the speed reducer and to cool the driving source; andwherein the lubricant oil is supplied to the bearing to lubricate the bearing.

6. The drive unit of claim 4 further comprising a supporting rotary shaft that supports and rotates along with the wheel; the supporting rotary shaft being inserted inside of a case, linked to the wheel via a rotary part formed on an outer circumference of the case, and linked to the carrier.

7. The drive unit of claim 1 wherein the rotary member of the bake unit rotates along with the wheel through the speed reducer.

8. The drive unit of claim 7 further comprising; a case having a top, an inside and an outside, the case housing the rotary member of the brake unit, anda flow path formed at the top of the case that links the inside of the case to the outside of the case for air circulation.

9. The drive unit of claim 7 further comprising fins on the rotary member of the brake unit.

10. The drive unit of claim 7, wherein the brake unit comprises a drum brake unit and the rotary member of the brake unit comprises a brake drum.

11. The drive unit of claim 7, wherein the brake unit comprises a disc brake unit and the rotary member of the brake unit comprises a brake disc, wherein the disc brake unit comprises a brake caliper attached below the disc brake unit for pushing against the brake disc.

12. The drive unit of claim 1 further comprising: a spindle inserted inside of the rotary shaft of the driving source, so that the spindle supports the wheel for free rotation on the spindle.

13. The drive unit of claim 1, wherein the rotary shaft of the driving source comprises a cap like rotary body having a rotary axis that connects to the speed reducer.

14. The drive unit of claim 1 further comprising a case that covers the speed reducer and the driving source with lubricating oil to provide lubricating oil to the speed reducer and to cool the driving source.

15. The drive unit of claim 1 further comprising a case that covers the speed reducer and the brake unit with lubricating oil to provide lubricating oil to the speed reducer and to cool the brake unit.

16. A drive unit for driving a wheel installed on a vehicle, the drive unit comprising: a driving means for rotating the wheel,a speed-reducing means for reducing a rotational speed of the driving means and for transmitting the reduced rotational speed to the wheel, anda braking means for braking the rotational speed of the wheel through the speed-reducing means.

17. A method for driving a wheel installed on a vehicle comprising: driving the wheel with a rotational power source through a speed reducer,increasing a rotational speed of the rotational power source to the wheel using the speed reducer, andbraking the rotational speed of the wheel through the speed reducer.