Vehicle Speed Sensor Mounting in Swing Arm
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Solution Overview
Problem
Existing vehicle speed sensor arrangements in vehicles with rear wheel axles and swing arms require additional space and protective covers, leading to increased swing arm length and vulnerability to disturbances and water splashes.
Innovation Solution
A vehicle speed sensor arrangement where the pickup is mounted on the swing arm to face the detected portion on the final gear, with the detected portion on one axial end surface and the pickup extending parallel to the axle, covered by a cover, and a conducting wire routed within the swing arm, allowing for reduced swing arm size and protection from disturbances and water.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pickup is mounted on the rear portion of the swing arm extending radially outward, then the vehicle speed sensor can detect the final gear rotation, but a protective cover is required and the swing arm length increases
Solution Approach 1:
The pickup mounting position is changed from radial extension to axial extension parallel to the axle. The detected portion is moved from the outer periphery to the axial end surface of the final gear. This dimensional change allows the pickup to be positioned inside the swing arm rather than extending outward, reducing the swing arm length while maintaining detection functionality.
2Length of stationary object
If the pickup is arranged inside the swing arm, then the swing arm length is reduced, but additional space must be ensured in the longitudinal direction
Solution Approach 1:
The pickup is nested within the swing arm structure by positioning it inside the swing arm main body. The conducting wire is routed through the swing arm interior space. This nesting arrangement utilizes the existing swing arm volume efficiently, accommodating the pickup and wiring without requiring additional longitudinal extension of the swing arm.
3Reliability
If the pickup extends outward from the swing arm, then vehicle speed detection is possible, but the pickup is exposed to disturbances and water splashes
Solution Approach 1:
The cover that originally served only as a protective element is transformed into an integrated part of the sensor assembly. The cover includes a through-hole that positions the pickup while the cover itself protects the pickup from water and disturbances. This converts the protective cover from a separate protective element into an integral part of the detection system, eliminating the need for additional sealing members.
4Object-affected harmful factors
If a protective cover is provided for the pickup, then the pickup is protected from disturbances, but the device complexity increases with sealing members
Solution Approach 1:
The protective cover and the pickup mounting structure are merged into a single integrated component. The cover includes the pickup mounting hole and positioning features directly formed on it, eliminating the need for separate sealing members and mounting brackets. This merging reduces the number of parts and assembly steps while maintaining protection functionality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This arrangement reduces the swing arm's front-and-rear length, eliminates the need for sealing members, and ensures continuous vehicle speed detection even when the centrifugal clutch is disengaged, while preventing disturbances and water exposure to the pickup.
Implementation Method 1
a pickup forming a vehicle speed sensor together with a detected portion that is provided on the final gear is mounted on the swing arm so as to face the detected portion
Data Source
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AI summary
In a vehicle in which: power transmission means for transmitting power from a power source to an axle of a rear wheel is accommodated in a swing arm that is swingably supported on a vehicle body frame; a final gear of a reduction gear train constituting a part of the power transmission means is fixed to the axle; and a pickup forming a vehicle speed sensor together with a detected portion that is provided on the final gear is mounted on the swing arm so as to face the detected portion, the detected portion (108) is provided on one of opposite axial end surfaces of the final gear (103) and the pickup (109) is mounted on the swing arm (22A) so as to extend parallel to an axis of the axle (21). Accordingly, it is possible to reduce the size of the swing arm by preventing an increase in a length in a front-and-rear direction of the swing arm even when the pickup is arranged in the swing arm.