Disc Brake Piston Elastic Drive Suppresses Drag
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Solution Overview
Problem
Disc brakes with hydraulic and electromechanical actuation modes experience residual drag moments due to the limitations of the rollback function, which cannot be fully utilized in electromechanical actuation, leading to unwanted drag and increased fuel consumption.
Innovation Solution
The actuating piston is coupled to a mechanical actuator via an elastically deformable driving arrangement, dissociating the rollback function from the seal between the housing and piston, allowing for a restoring movement that actively draws back the brake lining and prevents residual drag moments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rollback function is implemented using the hydraulic seal between the housing and actuating piston, then residual drag moments are suppressed in hydraulic actuation mode, but the rollback function cannot be fully utilized in electromechanical actuation mode due to absence of hydraulic pressure
Solution Approach 1:
The patent divides the rollback function into two independent components: the hydraulic seal rollback (for hydraulic actuation) and the elastic driving arrangement rollback (for electromechanical actuation). This segmentation allows each component to be optimized for its specific actuation mode, ensuring reliable suppression of residual drag moments in both modes without interference between them.
Solution Approach 2:
The elastic driving arrangement acts as an intermediary mechanism that provides the rollback function specifically for electromechanical actuation. It mediates between the actuator and actuating piston, enabling the piston to return to its initial position without requiring hydraulic pressure, thus solving the adaptability problem across different actuation modes.
2Force
If the hydraulic seal is designed to provide rollback function, then the adhesive contact holding forces increase with hydraulic pressure, but in electromechanical actuation without hydraulic pressure the adhesive contact breaks away before the end position is attained
Solution Approach 1:
The patent changes the physical parameters of the driving arrangement by making it elastically deformable. This allows the driving arrangement to provide sufficient holding forces through elastic deformation and friction, enabling the actuating piston to reach the precise end position in electromechanical actuation mode without relying on hydraulic pressure to increase adhesive contact forces.
3Reliability
If an elastically deformable driving arrangement is introduced between the actuator and actuating piston, then the rollback function is dissociated from the hydraulic seal and assigned to the driving arrangement, but this increases the device complexity
Solution Approach 1:
The elastic driving arrangement is designed to serve multiple functions: it transmits actuating forces from the actuator to the actuating piston, provides the rollback function for electromechanical actuation, and works in conjunction with the hydraulic seal for hydraulic actuation. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in device complexity while achieving reliable suppression of residual drag moments in all operating modes.
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 effectively suppresses residual drag moments in all operating modes, improving brake functionality and reducing fuel consumption by ensuring the actuating piston is fully returned to its initial position, regardless of the actuation method.
Implementation Method 1
the actuating piston is coupled to the mechanical actuator via an elastically deformable driving arrangement, wherein, as a consequence of a relative displacement between the actuating piston and the actuator, the driving arrangement provides a restoring movement in accordance with its elastic deformation
Implementation Method 2
the hydraulic seal, retained in the housing in the receiving groove there, undergoes an elastic deformation, which can relax elastically back into its initial state following abatement of the actuating force and, in so doing, draws the brake piston back into an initial position
Data Source
AI summary
A disc brake for a motor vehicle, wherein the disc brake comprises a housing, a brake disc which can be rotated relative to the housing, at least one friction lining, and at least one actuating device which is configured for bringing about a relative movement between the brake disc and the friction lining, with the result that the friction lining can be brought into contact with the brake disc, wherein the actuating device has at least one actuating piston which is guided displaceably in the housing in a hydraulically sealing manner, wherein the actuating piston can be displaced in the housing hydraulically and via a mechanical actuator. In the disc brake, it is provided that the actuating piston is coupled to the mechanical actuator via an elastically deformable driving arrangement, wherein, as a consequence of a relative displacement between the actuating piston and the actuator, the driving arrangement provides a restoring movement in accordance with its elastic deformation.