Shift drum drive unit and straddle type vehicle

Patent metadata

Field	Value
Publication number	US-10890254-B2
Application number	US-201615745986-A
Country	US
Kind code	B2
Filing date	Jun 17, 2016
Priority date	Jul 22, 2015
Publication date	Jan 12, 2021
Grant date	Jan 12, 2021

Abstract

A shift drum drive unit (230) rotatably includes a rotary drive body (231) and a power transmission mechanism (232) in a unit case (234) attached integrally with a crank case (111). The shift drum drive unit (230) further includes a shift actuator (233) on the outside of the unit case (234). The rotary drive body (231) includes a shaft fitting sleeve (231a) in which a shift shaft (225) configured to rotatably drive a shift drum (224) is fitted, and an indirect output gear (231b) having a fan-shaped gear partially projecting from an outer surface of the shaft fitting sleeve (231a). The power transmission mechanism (232) includes a gear configured to transmit rotary drive force of the shift actuator (233) to the indirect output gear (231b).

First claim

The invention claimed is:

1. A shift drum drive unit for rotatably driving a shift drum in a straddle type vehicle, the vehicle including
an engine configured to generate drive force by fuel combustion,
a transmission configured to change, for the drive force of the engine, a rotation speed by a plurality of gear trains forming a plurality of gear stages with different transmission gear ratios from one another, and
a shift shaft formed in a shaft shape, protruding from an inside of a crank case forming a portion of the engine, and configured to rotatably drive the shift drum for changing the gear trains of the transmission in the crank case,
the shift drum drive unit comprising:
a shift actuator configured to rotatably drive the shift drum;
a rotary drive body into which the shift shaft is inserted and which is rotatably driven together with the shift shaft by the shift actuator; and
a unit case configured to support the shift actuator and to house an entirety of the rotary drive body in a state in which the rotary drive body is rotatable, wherein
the unit case includes
an inner case facing the crank case and an outer case facing an opposite side of the crank case,
an insertion port for inserting the shift shaft into the rotary drive body, and
an attachment section consisting of one or more bolts for attachment of the unit case to the crank case, and

the attachment section penetrates the unit case and is attached to the crank case, thereby integrating the inner case and the outer case together.

2. The shift drum drive unit according to claim 1 , further comprising
a power transmission mechanism configured to transmit rotary drive force of the shift actuator to the rotary drive body, thereby rotatably driving the rotary drive body, wherein
the unit case houses an entirety of the power transmission mechanism.

3. The shift drum drive unit according to claim 2 , wherein
the rotary drive body is a direct output gear directly and rotatably supported in the unit case.

4. The shift drum drive unit according to claim 2 , wherein
the rotary drive body includes
a shaft fitting sleeve which is directly and rotatably supported in the unit case and into which the shift shaft is inserted, and
an indirect output gear attached to the shaft fitting sleeve to be rotatable together with the shaft fitting sleeve.

5. The shift drum drive unit according to claim 1 , wherein
the rotary drive body is a direct output gear directly and rotatably supported in the unit case.

6. The shift drum drive unit according to claim 1 , wherein
the rotary drive body includes
a shaft fitting sleeve which is directly and rotatably supported in the unit case and into which the shift shaft is inserted, and
an indirect output gear attached to the shaft fitting sleeve to be rotatable together with the shaft fitting sleeve.

7. The shift drum drive unit according to claim 1 , wherein one end portion of the shift shaft penetrates one wall of the crank case and is coupled with the shift drum through a return spring, and other end portion of the shift shaft penetrates another wall of the crank case to protrude outward of the crank case.

8. The shift drum drive unit according to claim 1 , wherein the one or more bolts comprises two attachment bolts arranged at a periphery of the rotary drive body.

9. A straddle type vehicle including
an engine configured to generate drive force by fuel combustion,
a transmission configured to change, for the drive force of the engine, a rotation speed by a plurality of gear trains forming a plurality of gear stages with different transmission gear ratios from one another, and
a shift shaft formed in a shaft shape, protruding from an inside of a crank case forming a portion of the engine, and configured to rotatably drive a shift drum for changing the gear trains of the transmission in the crank case,
the straddle type vehicle comprising
a shift drum drive unit including
a rotary drive body into which the shift shaft is inserted and which is rotatably driven together with the shift shaft,
a shift actuator configured to rotatably drive the rotary drive body, and
a unit case configured to support the shift actuator and to house an entirety of the rotary drive body with the unit case rotatably supporting the rotary drive body, wherein

the unit case includes
an inner case facing the crank case and an outer case facing an opposite side of the crank case,
an insertion port for inserting the shift shaft into the rotary drive body, and
an attachment section consisting of one or more bolts for attachment of the unit case to the crank case, and

the attachment section penetrates the unit case and is attached to the crank case, thereby integrating the inner case and the outer case together.

10. The straddle type vehicle according to claim 9 , wherein one end portion of the shift shaft penetrates one wall of the crank case and is coupled with the shift drum through a return spring, and other end portion of the shift shaft penetrates another wall of the crank case to protrude outward of the crank case.

11. The shift drum drive unit according to claim 9 , wherein the one or more bolts comprises two attachment bolts arranged at a periphery of the rotary drive body.

Assignees

• Fcc Kk

Inventors

• Makita Shouji
• Miyachi Kazuyoshi
• Chiba Ryouhei
• Iida Kaoru

Classifications

• F16H61/32

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

• F16H63/18 Primary

  the final actuating mechanism comprising cams · CPC title

• F16H25/12

  with reciprocation along the axis of rotation, e.g. gearings with helical grooves and automatic reversal · CPC title