Slack Adjuster Clutch Relocation for Continuous Brake Adjustment
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Solution Overview
Problem
Conventional slack adjusters for vehicle brakes face design and manufacturing complexities due to the location of the one-way clutch, which also limits adjustments to discrete steps, increasing loads on clutch components and failing to maintain optimal clearance between friction linings and the friction surface as they wear.
Innovation Solution
The automatic slack adjuster relocates the one-way clutch within the wear adjustment mechanism, away from the driving worm screw and control worm wheel interface, and employs a wrap spring instead of a toothed clutch, allowing for continuous adjustment and reducing design and manufacturing complexities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the one-way clutch is located between the driving worm screw and control worm wheel, then the clutch can transfer forces and enable adjustment, but this creates design and manufacturing complexities and places significant loads on the clutch components
Solution Approach 1:
The patent extracts the one-way clutch from its conventional location between the driving worm screw and control worm wheel, and relocates it to the wear adjustment mechanism. This separation removes the clutch from the high-load force transfer path while maintaining its adjustment function, thereby reducing design and manufacturing complexities and lowering loads on clutch components.
2Ease of operation
If a toothed clutch is used for adjustment, then discrete adjustments can be made, but this limits the ability to adjust clearance continuously
Solution Approach 1:
The patent changes the fundamental parameter of the clutch mechanism from a toothed (discrete) design to a wrap spring (continuous) design. The wrap spring allows for incremental, continuous adjustment of the brake clearance by winding or unwinding, providing infinite adjustment positions rather than discrete steps, thereby enhancing adaptability while maintaining ease of operation.
3Force
If the clutch is positioned at the driving worm screw and control worm wheel interface, then force transfer is enabled, but this places relatively significant loads on the clutch components
Solution Approach 1:
The patent extracts the one-way clutch from the high-stress interface between the driving worm screw and control worm wheel, relocating it to the wear adjustment mechanism. This repositioning removes the clutch from the primary force transfer path, significantly reducing the mechanical loads and stress on clutch components while maintaining the necessary force transfer capability through the worm screw and worm wheel engagement.
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 solution simplifies the design and manufacturing of the slack adjuster, reduces loads on clutch components, and enables continuous adjustment of the brake clearance, maintaining optimal friction lining positioning despite wear.
Implementation Method 1
a wrap spring engaging surfaces of the clutch ring and control worm screw
Implementation Method 2
a pinion gear in mesh with the control ring gear and configured for rotation about a rotational axis
Implementation Method 3
a driving worm screw supported by the housing and in mesh with the driving worm wheel. The driving worm screw is configured to transfer a brake actuating force
Data Source
AI summary
A vehicle brake slack adjuster includes a housing coupled to a brake actuator and supporting a driving worm wheel engaging the brake cam shaft and a driving worm screw meshed with the driving worm wheel and transferring a brake actuating force, imparted by the brake actuator to the housing, to the driving worm wheel and cam shaft. The adjuster further includes a wear adjustment mechanism including a reference arm fixed against movement and including a control ring gear, a pinion gear meshed with the control ring gear and configured for rotation about an axis, a clutch ring disposed about the axis and configured for rotation with the pinion gear, a control worm screw disposed about the axis, a wrap spring engaging surfaces of the clutch ring and control worm screw and a control worm wheel meshed with the control worm screw and configured for rotation with the driving worm screw.