Saddle-Type Vehicle Brake Cable Routing Layout

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Solution Overview

Problem

The existing combined brake device in straddled vehicles has a lengthy transmission path from the brake pedal to the front brake device, which complicates the layout and often results in interference with movable members, leading to inefficiencies in brake operation due to the long path and the need to avoid collisions with suspension and steering components.

Innovation Solution

The implementation of a drum brake as the front brake device allows for a direct connection of the combined brake cable, shortening the transmission path and employing a segmented brake cable layout that follows the vehicle's motion to minimize interference with suspensions and steering components, thereby maintaining efficient brake operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a disc brake is used as the front brake device, then the brake performance is improved, but the transmission path becomes considerably long and layout becomes difficult

Engineering Contradiction:
Improvebrake performanceVSAvoidtransmission path length
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent introduces a master cylinder as an intermediary component between the combined brake cable and the front brake caliper. The master cylinder converts the mechanical pull from the brake cable into hydraulic pressure, which then actuates the brake caliper. This intermediary mechanism allows the use of a disc brake system while managing the transmission path length through efficient spatial arrangement of the master cylinder near the handle assembly.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the combined brake cable extends from the equalizer to the master cylinder passing through positions backward and above the engine, then the brake force transmission is achieved, but the transmission path becomes long and layout is complicated

Engineering Contradiction:
Improvebrake force transmissionVSAvoidlayout complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes three-dimensional spatial arrangement to optimize the brake cable path. The master cylinder is positioned at the handle assembly, allowing the brake cable to route through the upper portion of the vehicle structure rather than following a lengthy path below the engine. This dimensional repositioning reduces cable length and simplifies the overall layout while maintaining effective brake force transmission.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of operation

If the front wheel and suspensions are made movable for steering and suspension functions, then the vehicle maneuverability is improved, but the combined brake cable may interfere with these movable members

Engineering Contradiction:
Improvevehicle maneuverabilityVSAvoidcable interference with movable members
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The master cylinder serves as a fixed intermediary mounting point at the handle assembly, which remains stationary relative to the movable front wheel and suspensions. By anchoring the brake system's hydraulic actuation point at this fixed location, the patent isolates the brake cable from the dynamic movements of the steering and suspension components, preventing interference while maintaining full maneuverability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3444174B1Saddle-type vehicle
Publication Date: 2021.06.02 YAMAHA MOTOR CO LTD
  • EP3444174B1 patent drawingFigure 1
  • EP3444174B1 patent drawingFigure 2
  • EP3444174B1 patent drawingFigure 3

AI summary

A first portion of a combined brake cable is disposed in a first region, extends forward and upward from a combined actuation mechanism, and passes through a lateral side of an engine so as to overlap the engine as seen in a vehicle side view. A third portion of the combined brake cable is disposed in a second region, extends downward and forward, and is connected to a front brake device. A second portion of the combined brake cable is connected to the first portion and the third portion. The second portion extends to cross the middle of a vehicle in a vehicle width direction, while passing between a lower frame and right and left suspensions in a vehicle back-and-forth direction. The second portion is located below at least part of a lower bracket. The second portion is attached to the vehicle body frame in a position between a left edge of the left suspension and a right edge of the right suspension in the vehicle width direction.