Shift Actuator Layout for Motorcycle Footrest Space

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Solution Overview

Problem

In motorcycle shifting mechanisms, the shift actuator and shift spindle are often located far apart vertically, requiring a lengthy link mechanism and compromising foot rest space for the rider due to inefficient use of available space.

Innovation Solution

A compact shift actuator layout is achieved by positioning the shift actuator below a cover member on the crankcase, parallel to the crankshaft, and using a gear mechanism within the arcuate wall surfaces of cover members to reduce the length of the power unit, allowing for a more compact arrangement and preservation of foot rest space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the shift actuator is mounted on the crankcase at a rear side of the cylinder, then the shift actuator can be located in the dead space on the front upper side of the main step, but the shift actuator and shift spindle are located distantly from each other in the vertical direction, requiring a lengthy link mechanism and additional space

Engineering Contradiction:

Improvefoot rest spaceVSAvoidlink mechanism length

Core Design Contradiction:

Area of stationary objectVSLength of stationary object

Solution Approach 1:

The shift actuator is repositioned from a vertical arrangement to a horizontal arrangement below the cover member, changing the spatial dimension of connection. This dimensional shift allows the actuator to be close to the shift spindle while maintaining foot rest space above, eliminating the need for a lengthy vertical link mechanism.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Volume of stationary object

If the shift actuator is located below the longitudinal range of the cover member, then the dead space can be efficiently used, but the arrangement must avoid interfering with the exhaust pipe and maintain adequate ground clearance

Engineering Contradiction:

Improvedead space utilizationVSAvoidinterference with exhaust pipe

Core Design Contradiction:

Volume of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The shift actuator is positioned in a specific local area below the cover member's longitudinal range, utilizing dead space that does not interfere with the exhaust pipe's path. This localized placement optimizes space utilization while avoiding harmful interference with other components.

Inventive Principle:

Principle #3Local quality

3Volume of moving object

If a gear mechanism is provided between the shift spindle and shift actuator, then the power unit can be made compact, but the gear mechanism requires space for its components

Engineering Contradiction:

Improvepower unit volumeVSAvoidspace for gear mechanism

Core Design Contradiction:

Volume of moving objectVSArea of stationary object

Solution Approach 1:

The gear mechanism is nested within the space between the cover member and the shift actuator, utilizing the vertical space efficiently. This nesting arrangement allows the power unit to be compact while accommodating all necessary gear components without requiring additional external space.

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentUS9074673B2Shift actuator layout structure in vehicle

Publication Date: 2015.07.07 HONDA MOTOR CO LTD

AI summary

In a vehicle having a generator cover mounted on one side of a crankcase so as to cover an end portion of a crankshaft projecting from the crankcase and a shift spindle located on the rear side of the generator cover as an input member of a shifting mechanism, a shift actuator is located below the longitudinal range of the generator cover in parallel to the crankshaft and on the front side of the axis of the shift spindle.