Power transmission unit for vehicle

Patent metadata

Field	Value
Publication number	US-9670971-B2
Application number	US-201314649683-A
Country	US
Kind code	B2
Filing date	Dec 25, 2013
Priority date	Dec 27, 2012
Publication date	Jun 6, 2017
Grant date	Jun 6, 2017

Abstract

A power transmission unit for a vehicle comprises: a motor arranged on an output side of an engine coaxially therewith in a housing adjacent to an outer face of the engine; an end cover arranged in the housing to cover an end portion of the motor to protect from the engine; a rotary shaft extending coaxially with the motor to be connected to an output shaft of the engine while penetrating through the end cover; and an engagement device disposed on an outer circumferential side of the rotary shaft between the motor and the engine to selectively restrict a rotation of the rotary shaft. A sub-cover to which the rotary shaft penetrates is attached to an end face of the end cover and a chamber is hermetically enclosed by the sub-cover, the end cover, and the rotary shaft. The engagement device is held in the housing.

First claim

The invention claimed is:

1. A power transmission unit for a vehicle, comprising:
a motor that is arranged on an output side of an engine coaxially therewith in a housing adjacent to an outer face of the engine;
an end cover that is arranged in the housing and fixed to an inner face of the housing to cover a coil end of the motor protruding toward the engine to protect the motor from the engine;
a rotary shaft that extends coaxially with the motor to be connected to an output shaft of the engine while penetrating through the end cover, the rotary shaft including an outer diameter smaller than an inner diameter of a stator of the motor;
an engagement device that is disposed on an outer circumferential side of the rotary shaft between the motor and the engine to selectively restrict a rotation of the rotary shaft;
a sub-cover which is liquid-tight attached to an end face of the end cover and to which the rotary shaft penetrates; and
a chamber that is enclosed by the sub-cover, the end cover, and the rotary shaft;
wherein the engagement device is held in the chamber.

2. The power transmission unit for a vehicle as claimed in claim 1 ,
wherein the chamber is situated in an inner circumferential side of the coil end.

3. The power transmission unit for a vehicle as claimed in claim 2 ,
wherein the end cover includes a recessed portion toward the motor at an inner circumferential side of the coil end; and
wherein the chamber is formed by closing the recessed portion of the end cover opening toward the engine by the sub-cover.

4. The power transmission unit for a vehicle as claimed in claim 1 ,
wherein the engagement device includes a one-way clutch that is brought into engagement to restrict a rotation of the rotary shaft when a torque is applied to the rotary shaft in a direction opposite to a rotational direction of the engine in a self-sustaining condition.

5. The power transmission unit for a vehicle as claimed in claim 4 ,
wherein the one-way clutch comprises an inner race whose inner diameter is larger than an outer diameter of the rotary shaft, and an outer race;
wherein the end cover is provided with a cylindrical boss portion protruding toward the housing along an inner circumferential side of the inner race to support the inner race in a rotatable manner; and
wherein the inner race is engaged with the rotary shaft to be rotated integrally therewith, and the outer race is connected integrally with the end cover or the sub-cover.

6. The power transmission unit for a vehicle as claimed in claim 5 ,
wherein the rotary shaft is engaged with the one-way clutch through a spline; and
wherein a radial clearance of the spline is kept wider than a total radial displacement of the inner race and the rotary shaft.

7. The power transmission unit for a vehicle as claimed in claim 6 , wherein the radial clearance in the spline is wider than a total radial displacement of the rotary shaft, the inner race and the outer race.

8. The power transmission unit for a vehicle as claimed in claim 5 , wherein an axial position of the outer race is fixed by the end cover and the sub-cover.

9. The power transmission unit for a vehicle as claimed in claim 5 , wherein the rotary shaft, the outer race and the inner race are supported by the end cover to be fixed in a radial direction.

10. The power transmission unit for a vehicle as claimed in claim 4 ,
wherein the one-way clutch comprises an inner race whose inner diameter is larger than an outer diameter of the rotary shaft, and an outer race;
wherein the end cover is provided with a boss portion protruding toward the housing while being engaged with an inner circumferential face of the inner race in a manner not to rotate therewith;
wherein the outer race comprises an engagement piece that is pushed toward an inner circumferential side of the outer race to be engaged with the inner race, and that is centrifugally withdrawn from the inner race to be disengaged therefrom;
wherein the outer race is engaged with the rotary shaft to be rotated integrally therewith; and
wherein a thrust bearing is interposed between the outer race and the sub-cover to support the outer race in a rotatable manner while fixing an axial position of the outer race.

11. The power transmission unit for a vehicle as claimed in claim 10 , further comprising:
an oil hole penetrating through the end cover to provide a communication between the chamber and a space holding the motor; and
wherein an opening end of the oil hole toward the chamber is situated in an outer circumferential side of the outer race.

12. The power transmission unit for a vehicle as claimed in claim 10 , wherein the rotary shaft is supported by the end cover.

13. The power transmission unit for a vehicle as claimed in claim 1 , further comprising:
an oil hole penetrating through the end cover to provide a communication between the chamber and a space holding the motor.

Assignees

• Toyota Motor Co Ltd

Inventors

• Okuda Kouichi
• Ibaraki Ryuji
• Yasuda Yuji
• Tabata Atsushi
• Kanada Toshiki
• Sato Isao
• Imamura Tatsuya

Classifications

• Y02T10/62

  Hybrid vehicles · CPC title

• Y02T10/6239

  Cross-Sectional Technologies · mapped topic

• F16H48/11

  having intermeshing planet gears · CPC title

• B60K6/383 Primary

  One-way clutches or freewheel devices · CPC title

• F16D41/069 Primary

  the intermediate members wedging by pivoting or rocking, e.g. sprags (F16D41/061 takes precedence) · CPC title