Motorcycle Swing Arm Recess for Heat-Shielded Speed Sensor
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Solution Overview
Problem
Conventional motorcycles face issues where the vehicle speed sensor is influenced by heat dissipated from the muffler, leading to increased width and cost due to the need for heat-resistant sensors or repositioning the muffler, which affects the vehicle's design and economics.
Innovation Solution
A recess is formed in the swing arm to house the vehicle speed sensor below the muffler, with a cover member protecting it from heat and foreign matter, and the sensor cable is also accommodated within this recess, maintaining the structural integrity and reducing the vehicle's width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the vehicle speed sensor is located close to the muffler, then the vehicle width can be reduced, but the sensor is influenced by heat dissipated from the muffler
Solution Approach 1:
The patent positions the vehicle speed sensor in the vertical dimension below the muffler rather than horizontally beside it. This vertical arrangement allows the sensor to be close to the muffler for compact vehicle width while the downward orientation of the sensor prevents direct exposure to heat dissipated upward from the muffler, thus resolving the contradiction between compact width and heat protection.
2Object-affected harmful factors
If the muffler is located outside of the swing arm in the lateral direction, then the heat influence on the sensor is reduced, but the vehicle width is increased
Solution Approach 1:
Instead of moving the muffler laterally outward to reduce heat influence, the patent keeps the muffler in its conventional lateral position for compact vehicle width. The heat protection is achieved by positioning the sensor vertically below the muffler and orienting it downward, thus eliminating heat exposure without increasing vehicle width.
3Object-affected harmful factors
If a vehicle speed sensor having heat resistance specifications is used, then the heat influence is tolerated, but the cost of the sensor is increased
Solution Approach 1:
Instead of using expensive heat-resistant sensors to tolerate heat exposure, the patent inverts the approach by positioning the sensor below the muffler where it is naturally protected from heat. This converts the potential harmful heat exposure into a beneficial shielding effect, allowing the use of standard, lower-cost sensors while maintaining reliability.
Data Source
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AI summary
To provide a motorcycle (10) in which the width of the vehicle can be suppressed and the influence of the heat dissipated from a muffler (47) upon a vehicle speed sensor (83) can be minimized. Disclosed herein is a motorcycle (10) including a swing arm (26), a muffler (47) provided on one side of the swing arm (26) and mounted thereto so as to be vertically moved together, a center rotor (84) mounted on a rear wheel (28) so as to be rotated together, and a vehicle speed sensor (83) mounted on the swing arm (26) for detecting a wheel speed in cooperation with the center rotor (84). The swing arm (26) has a recess (86) formed so as not to overlap the muffler (47) as viewed in side elevation of the vehicle, and the vehicle speed sensor (83) is provided in the recess (86). Further, a cover member (89) for covering the recess (86) is mounted on the swing arm (26).