V-belt CVT Sensor Mounting Inside Cover
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Solution Overview
Problem
The existing rotational speed sensor mounting structure in V-belt continuously variable transmission systems for straddle type vehicles increases the size of the transmission case and cover, restricting design freedom and component layout, especially in vehicles with limited space around the transmission device.
Innovation Solution
A V-belt continuously variable transmission system with a rotational speed sensor mounted on the inside of the transmission case cover, positioned on a plane containing the axes of the drive and driven shafts, and integrated with a sensor mounting boss section on the inner surface of the lateral wall, allowing for compact arrangement and reduced size increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the rotational speed sensor is mounted on the outside of the transmission case cover on the radially outward side of the movable driven pulley half body, then the sensor can detect the rotation speed of the fixed driven pulley half body, but the transmission case and cover increase in size in the radially outward direction
Solution Approach 1:
Instead of mounting the rotational speed sensor on the outside of the transmission case cover (conventional approach), the patent inverts the mounting location to the inside of the transmission case cover, specifically on the inner surface of the lateral wall section. This inversion eliminates the need for the case cover to extend radially outward, thereby preventing size increase while maintaining sensor functionality.
Solution Approach 2:
The patent changes the mounting dimension from radial (outside the case cover) to axial/longitudinal (inside the case cover on the lateral wall). By utilizing the lateral wall surface area rather than extending the radial dimension, the sensor is accommodated without increasing the overall size of the transmission case assembly.
2Measurement precision
If the rotational speed sensor is arranged on the outside of the transmission cover on the radially outward side of the movable driven pulley half body, then the sensor can detect rotation speed, but design freedom and component layout are restricted
Solution Approach 1:
The patent inverts the conventional mounting approach by placing the sensor inside rather than outside the transmission case cover. This provides greater design freedom as the sensor can be positioned on the lateral wall surface without constraining the overall component layout or requiring additional external space.
3Area of stationary object
If the rotational speed sensor is mounted on the inside of the transmission case cover on the lateral wall section, then size increase is prevented and design freedom is improved, but sensor support strength must be ensured
Solution Approach 1:
The patent applies local quality by creating a sensor mounting boss section with protruding portions on the inner surface of the lateral wall. This localized structural enhancement provides concentrated support strength at the sensor mounting location without requiring the entire transmission case cover to be thicker or more robust, thus maintaining overall compactness while ensuring adequate sensor support.
Solution Approach 2:
The sensor mounting boss section is designed as an integrated feature of the transmission case cover, with protruding portions that extend toward the driven pulley. This preliminary structural preparation ensures that when the sensor is mounted, it has immediate mechanical support and positioning, eliminating the need for additional reinforcement structures.
Data Source
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AI summary
To provide a V-belt continuously variable transmission system for a straddle type vehicle which is capable of avoiding an increase in size around a driven pulley of the V-belt continuously variable transmission system and of improving the freedom of design including layout of component parts, in relation to a mounting structure of a rotational speed sensor. A V-belt continuously variable transmission system for a straddle type vehicle has a belt transmission chamber (68) formed in an internal area between a transmission case (23) and a transmission case cover (80) for covering the transmission case (23) from the outside in the vehicle width direction. A drive pulley (61) pivotally supported on a drive shaft (40) extending in the vehicle width direction, a driven pulley (65) pivotally supported on a driven shaft (74) which is arranged in parallel with the drive shaft (40), and a V-belt (64) wrapped around the drive pulley (61) and the driven pulley (65), are accommodated in the belt transmission chamber (68). A rotational speed sensor (120) for detecting a rotational speed of the driven pulley (65) is mounted on the transmission case cover (80). The rotational speed sensor (120) is arranged on the inside of the V-belt (64) which is rotated in an annular shape, when viewed in the axial direction of the drive shaft (40).