Hydraulic Unit Positioning for Compact Motorcycle Front End
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Solution Overview
Problem
In small-size motorcycles, the arrangement of an ABS unit rearward of the head pipe increases the size of the front portion of the vehicle, making it difficult to reduce the front-and-rear dimensions due to the need for additional space for brake liquid hoses when the hydraulic unit is positioned leftward or rightward of the head pipe or headlamp.
Innovation Solution
The hydraulic unit is positioned downward relative to the headlamp, overlapping with it in the front view, and connected via a steel pipe and rubber hose, allowing for reduced bending of hoses and minimizing the space required for their curvature, enabling a more compact layout by using a steel pipe with a smaller diameter and higher rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the hydraulic unit is arranged leftwardly or rightwardly of the head pipe or headlamp, then the size of the front portion of the vehicle in the front-and-rear direction can be reduced, but the amount of bending of brake rubber hoses increases requiring larger space for hose bending
Solution Approach 1:
The hydraulic unit is repositioned from lateral arrangement (left/right of head pipe) to vertical arrangement (below headlamp), utilizing the vertical dimension to reduce front-and-rear length while minimizing hose bending through optimized connector positioning
2Ease of manufacture
If the hydraulic unit is fixed to the head pipe, then the master cylinder and caliper can be connected via rubber hoses, but the rubber hoses require flexibility and larger space for bending during handle operation
Solution Approach 1:
A connector is introduced as an intermediary component between the steel pipe and rubber hose, positioned at a specific location below the headlamp center to minimize rubber hose bending during handle operation while maintaining connection functionality
3Device complexity
If only one down frame is joined to the head pipe instead of a pair of upper pipes and lower pipes, then the structure is simplified, but no space is formed rearwardly of the head pipe for ABS unit storage
Solution Approach 1:
The ABS hydraulic unit is positioned in the vertical space below the headlamp rather than requiring rearward horizontal space, enabling compact front-end layout while maintaining simplified single down frame structure
Data Source
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AI summary
A hydraulic unit 70 is located at a position forward of a head pipe 10, farther downward than a headlamp 40 and farther upward than an under bracket 22. The hydraulic unit 70 overlaps with the headlamp 40 in a plan view of a vehicle. A master cylinder 18 and the hydraulic unit 70 are connected to each other via an upper pipe FL1, and the hydraulic unit 70 and a caliper 1C are connected to each other via a lower pipe FL2. The upper pipe FL1 includes a rubber hose 61, and the lower pipe FL2 includes a steel pipe 80 and a rubber hose 90 connected to each other with use of a connector 95. An end of a steel pipe 80 is connected to the hydraulic unit 70, and an end of the rubber hose 90 is connected to the caliper 1C. The connector 95 is located at a position farther downward than a center of the headlamp 40, and the rubber hose 90 is connected to the connector 95 at a position farther upward than the hydraulic unit 70.