Tractor Brake Pedal Return Spring Layout Around Rear Master Cylinder
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Solution Overview
Problem
The return spring in conventional tractors extends to the master-cylinder side from the brake pedal, complicating the engagement structure and limiting the space for the brake pedal's depression and movement.
Innovation Solution
The return spring is engaged to a partition disposed further toward the vehicle-body front side than the brake pedal, using the partition as a simple engaging member, and a torsion coil spring is supported by the support shaft to stabilize the brake pedal's biasing force, allowing the brake pedal to be accurately biased to the brake off position without additional support members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the return spring is engaged to the pedal arm portion and the cylinder case, then the brake pedal can be biased to the off position, but the return spring extends to the master-cylinder side complicating the engagement structure
Solution Approach 1:
The invention extracts the return spring engagement from the master cylinder area and relocates it to the partition structure. The return spring is now engaged between the pedal arm portion and the partition, separating the spring engagement function from the master cylinder assembly and simplifying the overall engagement structure.
Solution Approach 2:
The partition structure serves multiple functions: it separates the engine compartment from the driving unit, provides structural support, and acts as an engagement point for the return spring. This multi-functionality eliminates the need for separate engagement members, simplifying the structure.
2Productivity
If the master cylinder is disposed on the vehicle-body back side of the support shaft, then the braking system layout is optimized, but the return spring engagement becomes more complex
Solution Approach 1:
The partition acts as an intermediary structure between the pedal arm portion and the master cylinder area. It provides a convenient engagement point for the return spring without interfering with the master cylinder's optimal positioning on the vehicle-body back side, thus mediating between layout optimization and structural simplicity.
3Area of stationary object
If the partition is disposed further toward the vehicle-body front side than the brake pedal, then the footwell space is widened, but the return spring engagement point moves forward
Solution Approach 1:
The partition is positioned in the vehicle-body front-back dimension further forward than the brake pedal, creating additional space in the footwell area. This dimensional arrangement allows the return spring to engage with the partition without extending to the master-cylinder side, as the engagement occurs in a different spatial zone.
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 configuration maintains a simple engagement structure for the return spring, widens the space for brake pedal depression, and ensures stable, accurate biasing of the brake pedal to the off position, facilitating assembly and operation.
Implementation Method 1
the return spring is composed of a torsion coil spring comprising a coil portion, and the torsion coil spring is supported by the support shaft with the coil portion engaged with the support shaft
Data Source
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AI summary
[Problem] To provide a tractor that can keep a return spring from extending to a master-cylinder side while providing the master cylinder on a vehicle-body back side of a support shaft of a brake pedal and keep a structure of engaging the return spring simple. [Resolution Means] A master cylinder 43 is provided on a vehicle-body back side of a support shaft 44 of a brake pedal 41. A partition member 17 that is positioned on a vehicle-body front side of the brake pedal 41 and forms a partition between an engine compartment 15 and a driving unit 12 is provided. A return spring 42 that biases the brake pedal 41 to swing back to an initial position is engaged to the partition member 17 and to a pedal arm portion 41a of the brake pedal 41.