Motorcycle Crankcase Sensor Mounting Layout
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Solution Overview
Problem
Existing motorcycle designs with vehicle speed sensors protruding from the rear of the crank case increase the front-rear length of the engine and require additional structural protection against flying debris, such as stones.
Innovation Solution
A motorcycle design where the vehicle speed sensor is positioned in front of a breather chamber on the upper surface of the crank case, lower than the breather chamber's top, allowing it to be protected by the chamber's protrusion and reducing the engine's front-rear length by not protruding rearward.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the vehicle speed sensor is attached to protrude from the rear of the crank case, then the sensor can be positioned for detection, but the front-rear length of the engine increases
Solution Approach 1:
The vehicle speed sensor is repositioned from the rear surface of the crank case to the upper surface, utilizing a different spatial dimension. This dimensional shift allows the sensor to maintain its detection function while eliminating the need for rearward protrusion, thereby reducing the engine's front-rear length.
Solution Approach 2:
Instead of extending the sensor outward from the rear of the crank case, the invention inverts the approach by mounting the sensor on the upper surface and directing its detection section downward into the crank case. This inverted configuration achieves the same detection purpose without increasing the engine's length.
2Ease of operation
If the vehicle speed sensor is attached in a protruding manner from the rear, then the sensor is accessible, but additional structural protection against flying stones is required
Solution Approach 1:
The protective function is merged with the existing breather chamber structure. The breather chamber, which already protrudes upward from the crank case, is positioned to simultaneously protect the vehicle speed sensor from flying debris. This combination eliminates the need for separate protective structures while maintaining sensor accessibility.
Solution Approach 2:
The breather chamber is given a dual function: it continues to perform its original role of allowing crank case pressure equalization while also serving as a protective shield for the vehicle speed sensor. This multi-functionality reduces overall device complexity by eliminating dedicated protective structures.
3Length of moving object
If the vehicle speed sensor is positioned on the upper surface in front of the breather chamber, then the front-rear length is reduced, but the sensor must be positioned lower than the breather chamber top
Solution Approach 1:
The vehicle speed sensor is nested within the spatial envelope defined by the breather chamber's position. The sensor is mounted on the upper surface at a location and height that places it within the protective shadow of the breather chamber, allowing it to be shielded from flying debris while maintaining its detection function. This nesting arrangement satisfies both the length reduction goal and the protection requirement.
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 design effectively reduces the engine's front-rear length and provides enhanced protection for the vehicle speed sensor from flying debris while maintaining efficient engine operation and layout.
Implementation Method 1
a breather chamber protruding upward from a rear end of the crank case and adapted for accommodating separation of lubricating oil from blow-by gas generated in an engine
Data Source
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AI summary
A breather chamber (20) is provided at the rear end of a crank case (9) such that it protrudes upwardly. A vehicle speed sensor (17) detects the rotation speed of a main shaft (12) as a vehicle speed, and is fitted in front of the breather chamber (20) at an upper section of the crank case (9). Accordingly, as compared to a case where the vehicle speed sensor (17) is attached to a rear wall of the crank case (9) such that it protrudes rearward, the front-rear length of an entire engine (E) can be reduced. Further, because the vehicle speed sensor (17) is interposed between the breather chamber (20) and a cylinder (1) or a starter (11) standing in front of the vehicle speed sensor (17), it is simply protected from flying stones etc.