Double Cup Brake Piston Dome for Transverse Force Relief
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Solution Overview
Problem
Existing disc brake pistons face challenges in achieving a balance between easy handling, reduced hydraulic volume absorption, extended fatigue strength, and efficient component logistics, especially in heavy-duty applications with electromechanical parking brake devices, where transverse forces and misalignment can compromise performance.
Innovation Solution
A double cup-shaped piston design featuring a dome that forms an open receptacle for an electromechanical actuating device, allowing quasi-elastic deformation to neutralize transverse forces and optimize force flow, while incorporating a spindle-nut gear protection and reduced hydraulic volume through a slim dome wall and separate working spaces for improved decoupling and pad retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a simple cup-shaped piston design is used, then manufacturing is easier and component logistics are simplified, but the piston cannot effectively handle transverse forces and misalignment in electromechanical parking brake applications
Solution Approach 1:
The piston is divided into functionally distinct zones: a cylindrical base portion for simple manufacturing and a domed portion with receptacle for accommodating the electromechanical actuator. This segmentation allows each zone to be optimized for its specific function while maintaining overall structural integrity and ease of manufacture.
Solution Approach 2:
The piston transitions from a simple two-dimensional cup shape to a three-dimensional form with a domed portion and integrated receptacle. This dimensional evolution provides the necessary structural complexity to handle transverse forces and misalignment while maintaining manufacturing feasibility through progressive deformation processes.
2Reliability
If the piston includes a dome with receptacle for electromechanical actuator, then transverse forces are neutralized and force flow is optimized, but hydraulic volume absorption increases
Solution Approach 1:
The receptacle for the electromechanical actuator is nested within the domed portion of the piston, and the actuator components (spindle, nut, gear) are nested within the receptacle. This nesting arrangement minimizes the volume required for the actuator while maintaining its functional integrity and reducing the overall hydraulic working space volume.
Solution Approach 2:
The domed portion with its thin-walled structure provides a flexible yet rigid enclosure for the actuator, optimizing the balance between structural strength for force transmission and minimal volume occupation. The dome geometry efficiently distributes stresses while minimizing material usage and hydraulic volume.
3Volume of stationary object
If the dome wall is made slim to reduce hydraulic volume, then brake fluid usage is minimized, but the structural strength to handle maximum stress collective is reduced
Solution Approach 1:
The dome wall thickness is optimized locally: thinner in regions where structural strength is sufficient and hydraulic volume reduction is prioritized, and thicker in regions subject to maximum stress and fatigue loading. This local quality variation maintains fatigue strength while minimizing overall hydraulic volume.
Solution Approach 2:
The piston is constructed from materials with optimized mechanical properties that provide high strength-to-volume ratio. The material selection and potential composite structures enable the dome wall to achieve both slim dimensions for volume reduction and sufficient thickness for fatigue strength under maximum stress conditions.
4Ease of operation
If the piston is designed as one-piece deep-drawn component, then component logistics are rationalized and handling is easier, but the complexity of achieving precise geometric features increases
Solution Approach 1:
The piston geometry is prepared in advance through progressive deep-drawing and forming operations that create the basic cup shape, domed portion, and receptacle features before final assembly. This preliminary action sequence simplifies the manufacturing process and ensures geometric precision is achieved through controlled deformation stages rather than complex post-processing.
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 design enhances handling, reduces hydraulic volume, and extends fatigue strength by neutralizing transverse forces, minimizing brake fluid usage, and enabling efficient release of residual braking torque, while maintaining piston guide functionality under high loads without additional components.
Implementation Method 1
the influence of transverse forces/misalignment/angular misalignment/divergence between the piston axis ax and the effect of the force can be neutralized by means of quasi-elastic deformation of the dome 6
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a double cup-shaped piston (1) for a disc brake comprising an electromechanical parking brake device. The object of the invention is to permit an improved compromise between easier operability, rationalised component logistics in piston production, reduced hydraulic volume uptake in cooperation with the wheel brake periphery, and enhanced fatigue strength under maximum collective stress, in particular for heavy-duty applications of a disc brake with an electromechanical parking brake device. The problem is solved by the presence of a piston wall (2), which is provided, on the one hand, to sit with a free edge (3) on a rear plate (4) of a friction lining (5), and wherein the piston (1), on the other hand, comprises an integral dome (6) which forms an open receptacle (7) for an actuator (SV) arranged diametrically to the edge (3) of the piston (1).