Vehicle power unit

Patent metadata

Field	Value
Publication number	US-11085533-B2
Application number	US-201916371485-A
Country	US
Kind code	B2
Filing date	Apr 1, 2019
Priority date	Apr 5, 2018
Publication date	Aug 10, 2021
Grant date	Aug 10, 2021

Abstract

In a vehicle power unit, a drum rotary shaft member on one side of a shift drum is provided with a driven gear. A case side wall on one side of an engine crankcase supporting the drum rotary shaft member is covered by a case cover member in opposing relation thereto. A shift motor is mounted to the case cover member, with a driving gear thereof directed to protrude toward the case side wall. A speed reducing gear train has gear shafts and provides a multiplicity of speed reduction stages for transmitting power from the driving gear to the driven gear. The speed reducing gear train is arranged with both ends of its gear shafts thereof supported on the case side wall and the case cover member, respectively. Such arrangement provides a vehicle power unit for a fast and smooth shift by an electric motor.

First claim

The invention claimed is:

1. A vehicle power unit longitudinally mounted on a small-type vehicle, wherein an internal combustion engine and a transmission system are integrally supported on a crankcase of the power unit and wherein the transmission system includes a transmission having gear pairs differing in transmission gear ratio for transmitting power, and a shift driving mechanism having a shift drum rotated by a shift motor to make a shift by changing the gear pair for transmitting power in the transmission through movement of a shift fork guided by the shift drum, characterized in that:
the shift drum has rotary shaft members at its both ends rotatably supported on both case side walls of the crankcase;
one of the drum rotary shaft members of the shift drum is provided with a driven gear;
one of the case side walls of the crankcase supporting the one drum rotary shaft member provided with the driven gear is covered by a case cover member in opposing disposition thereto;
the shift motor is supported by the one case cover member with its driving gear protruding toward the one case side wall;
a speed reducing gear train having gear shafts to provide a multiplicity of speed reduction stages for transmitting power from the driving gear to the driven gear is arranged with ends of the gear shafts thereof supported on the one case side wall and the one case cover member, respectively;
the speed reducing gear train is arranged to surround the driving gear; and
the speed reducing gear train has speed reducing gears overlapping with the shift motor in an axial direction of an axis of the driving gear view.

2. The vehicle power unit according to claim 1 , wherein:
the transmission has main shafts under which the shift drum is disposed;
clutch devices are provided at end portions of the main shafts, the end portions protruding beyond the one case side wall; and
the shift motor is disposed under the clutch devices.

3. The vehicle power unit according to claim 2 , wherein:
the clutch devices are covered by a clutch cover; and
the shift motor is located under the clutch cover.

4. The vehicle power unit according to claim 3 ,
wherein a drum rotational angle sensor for detecting rotational angle of the shift drum is mounted to the case cover member while being interposed between the clutch cover and the shift motor, the drum rotational angle sensor being connected to an end portion, penetrating the case cover member, of the one drum rotary shaft member.

5. The vehicle power unit according to claim 1 ,
wherein an end portion of the other drum rotary shaft member opposite to the one drum rotary shaft member is a shifting knob for manual shifting operation.

6. The vehicle power unit according to claim 2 ,
wherein an end portion of the other drum rotary shaft member opposite to the one drum rotary shaft member is a shifting knob for manual shifting operation.

7. The vehicle power unit according to claim 3 ,
wherein an end portion of the other drum rotary shaft member opposite to the one drum rotary shaft member is a shifting knob for manual shifting operation.

8. The vehicle power unit according to claim 4 ,
wherein an end portion of the other drum rotary shaft member opposite to the one drum rotary shaft member is a shifting knob for manual shifting operation.

9. The vehicle power unit according to claim 1 , wherein:
the driving gear is arranged between the driven gear and each of the speed reducing gears of the speed reducing gear train in anaxial direction view of an axis of the driving gear.

Assignees

• Honda Motor Co Ltd

Inventors

• Kittaka Eiji
• Kudo Takashi

Classifications

• F16H57/02

  Gearboxes; Mounting gearing therein · CPC title

• F16H3/006

  power being selectively transmitted by parallel flow paths, e.g. dual clutch transmissions · CPC title

• F16H63/304

  the final output mechanisms comprising elements moved by electrical or magnetic force (band brake actuating mechanisms F16H63/3003) · CPC title

• F16H61/32 Primary

  Electric motors  {, actuators or related electrical control means}  therefor · CPC title

• B60Y2200/124

  Buggies, Quads · CPC title