Drive unit for hybrid vehicle

Patent metadata

Field	Value
Publication number	US-11772477-B2
Application number	US-202117501605-A
Country	US
Kind code	B2
Filing date	Oct 14, 2021
Priority date	Nov 17, 2020
Publication date	Oct 3, 2023
Grant date	Oct 3, 2023

Abstract

A drive unit for a hybrid vehicle that is downsized without reducing N.V. performance. The drive unit comprises: a geared transmission that transmits torque between a power split mechanism and a differential unit; and a reduction mechanism that multiplies torque of a second motor to be delivered to the differential unit. In the drive unit, an engine, a first motor, the power split mechanism, and a counter drive gear are arranged around a first rotational axis, the differential unit, the second motor, the reduction mechanism, driveshafts, and a differential ring gear are arranged around a second rotational axis, and a counter driven gear is arranged around a third rotational axis. The reduction mechanism is positioned without overlapping with the engine, the first motor, and the counter drive gear in an axial direction.

First claim

What is claimed is:

1. A drive unit for a hybrid vehicle, the drive unit comprising:
a prime mover including an engine, a first motor, and a second motor;
a pair of driveshafts each of which is connected to a respective one of a right drive wheel and a left drive wheel;
a power split mechanism that distributes an output torque of the engine to the first motor and the driveshafts;
a differential unit to which an output torque of the second motor is delivered, and which allows the driveshafts to rotate at different speeds;
a geared transmission that transmits a torque between the power split mechanism and the differential unit; and
a reduction mechanism that multiplies the output torque of the second motor to be delivered to the differential unit, wherein
the power split mechanism includes a planetary gear set comprising
an input element that is connected to the engine,
a reaction element that is connected to the first motor, and
an output element,

the geared transmission comprises
a counter drive gear that is connected to the output element,
a counter driven gear that is meshed with the counter drive gear, and
a differential ring gear that is meshed with the counter driven gear to transmit the torque to the differential unit,

the engine, the first motor, the power split mechanism, and the counter drive gear are arranged around a first rotational axis,
the differential unit, the second motor, the reduction mechanism, the driveshafts, and the differential ring gear are arranged around a second rotational axis extending parallel to the first rotational axis,
the counter driven gear is arranged around a third rotational axis extending parallel to the second rotational axis and the first rotational axis,
the reduction mechanism is offset from the engine, the first motor, and the counter drive gear in an axial direction of the first, second and third rotational axes so that the reduction mechanism does not overlap with any of the engine, the first motor, and the counter drive gear in the axial direction, and
the first, second and third rotational axes are spaced apart from each other in a direction perpendicular to the axial direction, with the third rotational axis being located between the first rotational axis and the second rotational axis in the direction perpendicular to the axial direction.

2. The drive unit as claimed in claim 1 , wherein the reduction mechanism is not offset from the power split mechanism in the axial direction so that the reduction mechanism overlaps with the power split mechanism in the axial direction.

3. The drive unit as claimed in claim 1 , wherein
the engine, the first motor, the power split mechanism, and the counter drive gear are arranged in order from one side in the axial direction, and
the second motor, the reduction mechanism, and the differential ring gear are arranged in order in the axial direction from said one side.

4. The drive unit as claimed in claim 1 , wherein
the power split mechanism includes a planetary gear set comprising
a first carrier that serves as the input element,
a first sun gear that serves as the reaction element, and
a first ring gear that serves as the output element, and

the reduction mechanism includes a stepped-pinion planetary gear set comprising
a second sun gear that is connected to the second motor,
a second ring gear that is fixed and not allowed to rotate,
a diametrically larger pinion that is meshed with the second sun gear,
a diametrically smaller pinion that is diametrically smaller than the diametrically larger pinion, and that is rotated integrally with the diametrically larger pinion while being meshed with the second ring gear, and
a second carrier that is connected to the differential ring gear while supporting the diametrically larger pinion and the diametrically smaller pinion.

5. The drive unit as claimed in claim 4 , further comprising:
a case that holds the first motor, the power split mechanism, the geared transmission, the differential unit, the reduction mechanism, and the second motor, wherein
the case comprises a first bulkhead that closes a first end of the first motor in the axial direction, and a second bulkhead that closes a second end of the first motor in the axial direction,
the first motor comprises a hollow rotor shaft that rotates integrally with a rotor of the first motor,
the power split mechanism further comprises an input shaft that is connected to the engine and that is rotated integrally with the first carrier,
ends of the hollow rotor shaft are respectively supported by a first bearing held by the first bulkhead and a second bearing held by the second bulkhead, and
ends of the input shaft are also respectively supported by the first bearing and the second bearing through a third bearing and a fourth bearing arranged in a hollow space of the hollow rotor shaft.

6. The drive unit as claimed in claim 5 , wherein
the case further comprises a third bulkhead that closes a first end of the geared transmission in the axial direction, and a fourth bulkhead that closes a second end of the geared transmission in the axial direction,
ends of the counter drive gear are respectively supported by a fifth bearing held by the third bulkhead and a sixth bearing held by the fourth bulkhead, and
ends of the counter driven gear are respectively supported by a seventh bearing held by the third bulkhead and an eighth bearing held by the fourth bulkhead.

7. The drive unit as claimed in claim 1 , wherein
the engine, the counter drive gear, the power split mechanism, and the first motor are arranged in order from one side in the axial direction, and
the differential ring gear, the reduction mechanism, and the second motor are arranged in order in the axial direction from said one side in the axial direction.

8. The drive unit as claimed in claim 1 , wherein
the engine, the counter drive gear, the power split mechanism, and the first motor are arranged in order from one side in the axial direction, and
the reduction mechanism, the differential ring gear, and the second motor are arranged in order in the axial direction from said one side.

9. The drive unit as claimed in claim 1 , wherein
the engine, the counter drive gear, the power split mechanism, and the first motor are arranged in order from one side in the axial direction, and
the second motor, the differential ring gear, and the reduction mechanism are arranged in order in the axial direction from said one side in the axial direction.

10. The drive unit as claimed in claim 1 , wherein
the engine, the counter drive gear, the power split mechanism, and the first motor are arranged in order from one side in the axial direction, and
the second motor, the reduction mechanism, and the differential ring gear are arranged in order in the axial direction from said one side.

11. The drive unit as claimed in claim 1 , further comprising:
an additional reduction mechanism that is arranged between the second motor and the reduction mechanism to multiply the output torque of the second motor to be delivered to the reduction mechanism.

12. The drive unit as claimed in claim 1 ,
the counter drive gear, the counter driven gear, and the differential ring gear are arranged in a line that extends in the direction perpendicular to the axial direction.

13. The drive unit as claimed in claim 1 , wherein
an outer circumference of the reduction mechanism overlaps with an outer circumference of the first motor when viewed in the axial direction.

14. The drive unit as claimed in claim 13 ,
the outer circumference of the reduction mechanism overla

Assignees

• Toyota Motor Co Ltd

Inventors

• Shibata Hiroyuki
• Hattori Hiroyuki
• Murakami Akira

Classifications

• Y02T10/62

  Hybrid vehicles · CPC title

• B60K6/445 Primary

  Differential gearing distribution type · CPC title

• B60K6/365 Primary

  with the gears having orbital motion · CPC title

• B60K6/547

  the transmission being a stepped gearing · CPC title

• B60K2006/4833

  Step up or reduction gearing driving generator, e.g. to operate generator in most efficient speed range · CPC title