Brake Caliper Piston Retracting Device Elastic Energy Compensation
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Solution Overview
Problem
Existing piston retracting devices in brake calipers suffer from variability in caliper body strain under high braking pressures, leading to residual braking torque due to elastic recovery of the caliper body, which affects piston position and causes unintended braking action after the driver's intentional braking has stopped.
Innovation Solution
A piston retracting device with elastic means between the piston and caliper body that accumulates and returns elastic energy, allowing the piston to retract fully into its seat by a predefined stroke, compensating for caliper body elastic strain and reducing residual braking torque, by utilizing an elastic member that stores energy during piston movement and releases it when a minimum braking pressure threshold is exceeded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gasket is used as a retracting member that strains elastically during piston movement, then the piston can be returned to the seat after braking, but under high braking pressures the caliper body undergoes elastic strain that causes the piston to move toward the disc, creating residual braking torque
Solution Approach 1:
The elastic means is pre-configured to exert a counteracting force on the piston that opposes the harmful movement toward the disc. During braking, the elastic means stores energy and applies a preliminary counter-force that prevents the piston from moving too close to the disc, and after braking it actively pushes the piston back to compensate for caliper body elastic recovery, thereby preventing residual braking torque.
Solution Approach 2:
The elastic means changes its physical state (elastic deformation) in response to braking pressure changes. During high-pressure braking, the elastic means deforms to absorb the pressure-induced piston movement, and when pressure drops, it recovers its shape to push the piston back, dynamically adjusting the piston position to eliminate residual torque while maintaining reliable retraction.
2Force
If the caliper body is subjected to high braking pressures, then effective braking force is generated, but the caliper body undergoes elastic strain that moves the piston toward the disc independently of piston-seat relative movement
Solution Approach 1:
The elastic means acts as an intermediary element between the piston and the external environment. It mediates the effect of high braking pressures on the piston by absorbing the pressure-induced elastic strain of the caliper body through its own elastic deformation, thereby isolating the piston position from the harmful effects of caliper body strain while still allowing effective force transmission to the brake pads.
3Device complexity
If the piston is returned only by the limited elastic return of the gasket, then the retraction mechanism is simple, but the piston may not fully retract when caliper elastic strain recovers and pushes the piston toward the disc
Solution Approach 1:
The elastic means is designed with dynamic characteristics that allow it to adapt its retraction force to the operating conditions. During braking, it deforms elastically to accommodate piston movement, and during retraction it dynamically recovers its shape to provide the necessary push-back force. This dynamic behavior ensures complete piston retraction without requiring complex mechanical return mechanisms, maintaining simplicity while improving reliability.
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
The solution effectively compensates for caliper body elastic strain, ensuring precise piston retraction and eliminating residual braking torque, thereby improving braking system efficiency and reliability.
Implementation Method 1
elastic means arranged between said piston and said caliper body, so that, upon the withdrawing movement of the piston from the caliper body seat, said elastic means accumulate or store elastic energy both as a function of the piston movement relative to the seat thereof of the caliper body, up to a preset maximum threshold, and as a function of the amount of the piston urging action against said disc friction surfaces
Data Source
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AI summary
A brake caliper comprising a piston seat (10) wherein a piston (2) slides with its side surface (11) in contact with a radial surface (13) of an elastic member (12). The member further comprising two axial surfaces (15,16) adapted to be affected by a pressurized fluid and being arranged at the piston coming out side facing the pads respectively. The latter surface facing with a portion (17) thereof, a first chamber (18) arranged in the proximity of the piston side surfaces, with another portion (24) thereof, an abutment surface (19) adapted to support said elastic member when it is urged by the pressurized fluid, said abutment surface being radially retracted so as to be farther from the piston side surface than said first chamber and with a further portion (25) thereof, at least one second chamber (20) arranged radially farther from said piston side surface than said abutment surface.