Gear Position Sensor Mounting for Shift Drum Alignment
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Solution Overview
Problem
The existing methods for inserting a gear position sensor into a crankcase require significant force and often result in position deviation between the sensor and the shift drum due to the need to twist the sensor during assembly, leading to difficulties in achieving a smooth mounting process.
Innovation Solution
The design incorporates a circular insertion hole with varying inner diameters and surfaces to reduce initial insertion resistance, allowing the sensor to be easily aligned and seated, while a seal ring is used to maintain a secure fit and prevent position deviation by engaging the sensor's engagement pin with the shift drum's groove.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the gear position sensor is inserted into the insertion hole while twisting it to reduce insertion resistance, then the insertion process becomes easier, but the engagement pin deviates from the engagement groove causing mounting failure
Solution Approach 1:
The insertion hole is divided into three distinct sections along the insertion direction: a first section with a first inner diameter, a second section with a second inner diameter larger than the first, and a third section with a third inner diameter larger than the first. This segmentation allows the seal ring to pass through the larger-diameter sections easily while maintaining alignment in the critical engagement zone.
Solution Approach 2:
Different sections of the insertion hole have different inner diameters tailored to specific functional requirements. The second and third sections have larger diameters to facilitate seal ring insertion, while the first section maintains a smaller diameter to ensure precise alignment between the engagement pin and engagement groove.
2Reliability
If a seal ring is fitted to the outer peripheral surface of the gear position sensor to seal the insertion hole, then sealing is improved, but insertion resistance increases making assembly difficult
Solution Approach 1:
The insertion hole is segmented into three sections with different diameters. The second section has a larger second inner diameter that allows the seal ring to pass through easily, reducing insertion resistance while maintaining sealing functionality.
Solution Approach 2:
The insertion hole has locally different diameters: the second section has a larger diameter specifically where the seal ring needs to pass, while other sections maintain smaller diameters for alignment and sealing purposes.
Data Source
AI summary
A straddle vehicle comprises a shift drum formed with an engaged part; a transmission case formed with an insertion hole, a gear position sensor including an engagement part engageable with the engaged part; and a seal ring fitted to the outer peripheral surface of the gear position sensor, and the insertion hole includes a first inner peripheral surface with which the seal ring is in tight contact in a state in which the engagement part is engaged with the engaged part, and a second inner peripheral surface located closer to an entrance of the insertion hole than the first inner peripheral surface and having a diameter larger than a diameter of the first inner peripheral surface, and in a state in which the seal ring has reached an entrance of the first inner peripheral surface, at least a portion of the engagement part is fitted to the engaged part.