Friction Clutch Intermediate State for Motorcycle Gear Shift
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Solution Overview
Problem
Conventional gear change control systems in straddle-type vehicles, such as motorcycles, experience inadequate acceleration performance during gear changes due to the temporary disengagement of the clutch, leading to insufficient torque transmission and potential ride quality issues from excessive torque shock.
Innovation Solution
A gear change control system that shifts the friction clutch to an intermediate state before gear engagement, allowing torque transmission to begin before full engagement, and then restores it to the engaged state after gear engagement, reducing torque interruption time and shock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the clutch is temporarily shifted to a disengaged state during gear change, then the gears can be displaced and engaged without excessive torque shock, but torque transmission to the wheel is delayed resulting in insufficient acceleration performance
Solution Approach 1:
The clutch is shifted to an intermediate state before the gears are fully engaged by the dog clutches. This preliminary action allows torque to begin transmitting through the friction members while the gear displacement is still in progress, so that torque transmission is already underway when the gears lock into place, eliminating the acceleration gap without causing excessive shock at engagement.
2Speed
If the clutch is engaged before gear displacement is completed, then torque transmission to the wheel begins earlier improving acceleration performance, but excessive torque is transmitted to the wheel when the gears engage causing shock and degraded ride quality
Solution Approach 1:
The clutch control system dynamically adjusts the clutch state through three distinct phases: (1) shifting to an intermediate state before gear engagement to begin torque transmission, (2) maintaining the intermediate state during gear displacement to allow smooth engagement, and (3) restoring to the engaged state after gear engagement to resume full torque transmission. This dynamic control prevents excessive torque shock while maintaining acceleration performance.
3Object-affected harmful factors
If the clutch is controlled to shift to the engaged state gradually, then torque transmission is smooth preventing shock, but the time required for torque transmission to start increases reducing acceleration performance
Solution Approach 1:
The clutch is shifted to an intermediate state before gear engagement occurs, establishing torque transmission pathways in advance. This preliminary action ensures that when the gears engage, torque is already flowing through the friction members, eliminating the time delay associated with gradual clutch engagement while maintaining smooth torque transmission.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves acceleration performance by shortening torque transmission interruption and preventing ride quality degradation by managing clutch pressure to minimize engagement shock.
Implementation Method 1
a friction clutch (40) including a driving-side friction member (41) and a driven-side friction member (42) which are pressed against each other to transmit torque in an engaged state
Data Source
AI summary
A gear change control device actuates an actuator in response to an input of a gear change command and sets the clutch in an intermediate state between the engaged and disengaged states before a plurality of gears in the transmission are selectively engaged by dog clutches. In the intermediate state, a driving-side friction member and a driven-side friction member of the clutch are pressed against each other at a pressure lower than in the engaged state. The gear change control device actuates the clutch actuator to restore the friction clutch set in the intermediate state to the engaged state after the plurality of gears are selectively engaged.