Motorcycle Power Unit Actuator Vertical Relocation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional straddle-type vehicles with automatic gear change systems face challenges in downsizing the power unit due to the large size caused by a common actuator used for clutch connecting/disconnecting and gear-changing operations, which results in a bulky lower part of the power unit.
Innovation Solution
The power unit is designed with a crank shaft extending in the vehicle width direction, featuring a rotating body, transmission with plural gears, and a clutch connected/disconnected by a shift shaft. An actuator with an output shaft is positioned over the shift shaft, and a connection body links the shift shaft's projection part outside the casing, minimizing the lower unit's size and projection outside the vehicle width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a common actuator is used for clutch connecting/disconnecting and gear-changing operations, then the synchronization of timing is improved and gear changes can be performed smoothly in a short time, but the lower part of the power unit becomes large
Solution Approach 1:
The patent repositions the actuator from a horizontal arrangement (inside the power unit) to a vertical arrangement (above the shift shaft), utilizing the vertical dimension to reduce the horizontal footprint of the power unit. This dimensional change allows the actuator to achieve the same functional purpose while minimizing the overall volume occupied by the power unit components.
2Device complexity
If the motor is directly mounted on the lower part of the power unit, then the connection mechanism is simplified, but the lower part of the power unit becomes large for the motor
Solution Approach 1:
The actuator is extracted from the conventional position inside the power unit and relocated to a position above the shift shaft, outside the main power unit housing. This extraction removes the bulky actuator components from the constrained space within the power unit, allowing for a more compact overall design while maintaining the necessary connection functionality through an extended connection mechanism.
3Adaptability or versatility
If the actuator projects outside the power unit in the width direction, then the actuator can be accommodated, but the projection outside the power unit increases
Solution Approach 1:
Instead of accommodating the actuator by increasing the width (horizontal dimension) of the power unit, the patent utilizes the vertical dimension by positioning the actuator above the shift shaft. This dimensional transition allows the actuator to be accommodated without increasing the power unit's width, thereby maintaining a compact lateral profile while providing sufficient space for actuator operation.
Data Source
AI summary
A motorcycle includes a power unit. A fly wheel magnet on a left end side of a crank shaft, a transmission having plural gears, a transmission clutch and a shift shaft for connecting and disconnecting the transmission clutch and changing gears of the transmission are housed in a crank case of the power unit. A part of the shift shaft projects from the crank case. A projection part of the shift shaft and an output shaft of an actuator are connected outside the crank case by means of a connection body. A rod of a connection body extends vertically behind the fly wheel magnet.