Two-Wheeler Gear Selection Using Drive-Shaft Cam Shifting
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Solution Overview
Problem
Existing switching systems for two-wheeled vehicles require power flow interruption during gear changes, which is undesirable, especially under load conditions, and often necessitate high forces to engage or disengage switching devices.
Innovation Solution
The system utilizes the drive force or torque to induce movement of the switching device, allowing gear changes without load interruption by configuring the switching means to rotate with the drive shaft, using a branched-off force from the drive movement to transition between switching positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the switching system uses a planetary gear system controlled by cable pull to change switching position, then gear changes can be achieved, but the clamping forces become very large under load making switching impossible
Solution Approach 1:
The switching device uses itself to generate the switching force. The camshaft, which is already rotating with the drive shaft under load, generates the switching force through its cam profile. The rotation of the camshaft automatically produces the necessary force to move the switching element against the high clamping forces, eliminating the need for external cable pull systems.
Solution Approach 2:
The system transitions from a static cable-pull mechanism to a dynamic cam-based system. The cam profile is designed to convert the rotational motion of the drive shaft into the specific motion pattern needed to move the switching element. This dynamic approach allows the switching force to be generated continuously during rotation, enabling switching under load conditions.
2Ease of operation
If the switching system interrupts power flow to perform gear changes, then switching can be achieved, but transmission performance deteriorates especially under load
Solution Approach 1:
The drive shaft and camshaft continue to rotate continuously during the switching process, maintaining the power flow throughout the transmission system. The switching element is moved during the rotation of the camshaft without stopping the drive, ensuring that power transmission is not interrupted. This allows gear changes to occur seamlessly while maintaining transmission performance under load.
3Device complexity
If the switching means is stationary relative to the drive shaft, then the system structure is simple, but switching under load is impossible due to insufficient switching force
Solution Approach 1:
The switching means is made dynamic by mounting it on the rotating camshaft. The cam profile converts the rotational motion into the necessary linear or angular motion of the switching element. This dynamic mounting allows the switching force to be generated from the rotational energy of the drive shaft, providing sufficient force to overcome the high clamping forces under load conditions.
Data Source
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AI summary
The invention relates to a selection system (14) for shifting a gear unit (1), comprising at least one movably disposed selector shaft (19, 20) and at least one selection means (15, 16), in which system the selected position of the selection means (15, 16) can be changed by means of a movement of the selector shaft (19, 20) relative to the selection means (15, 16), and a drive shaft (18) which is rotatable about a centre axis (10) is designed as part of the selection system (14) and, in a first selected position of the selection means (15, 16), can be connected for conjoint rotation at least in one direction of rotation to a component (5) of the gear unit (1) and, in a second selected position of the selection means (15), can be decoupled from the component (5) of the gear unit (1) in each direction of rotation. According to the invention the selection means (15, 16) in conjunction with the drive shaft (18) is designed in such a way that at least a part of the selection means (15, 16) co-rotates with a rotation of the drive shaft (18) about the centre axis (10), so that the relative movement of the selection means (15, 16) with respect to the selector shaft (19, 20) can be generated. The invention further relates to a gear unit (1) having at least one such selection system (1).