Brake Piston-Spindle Joint for Coaxiality Deviation Absorption
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Solution Overview
Problem
Existing piston actuation devices in brake systems face challenges due to coaxiality deviations between the piston guidance axis and the spindle movement axis, leading to wear on the axial guidance and increased production costs due to the need for wear protection coatings.
Innovation Solution
The use of an articulated joint, comprising a plug element and a plug socket forming a frictional connection, allows for concentricity deviations without inducing transverse forces, thereby eliminating the need for wear protection coatings and simplifying production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a rigid linkage between piston and spindle is used, then the connection is structurally simple, but coaxiality deviations cause wear-producing transverse forces on the axial guidance
Solution Approach 1:
The rigid linkage is replaced with an articulated joint comprising a plug element with spherical head and a plug socket, enabling dynamic adaptation to coaxiality deviations. This allows the connection to accommodate misalignment through angular movement rather than transmitting transverse forces to the axial guidance.
Solution Approach 2:
The plug element features a spherically curved head that engages with the plug socket, creating a spherical joint. This spherical geometry allows rotational and angular freedom, enabling the joint to compensate for coaxiality deviations without generating harmful transverse forces on the piston's axial guidance.
2Reliability
If wear protection coating is applied to the axial guidance region, then wear resistance is improved, but production time and cost increase
Solution Approach 1:
The solution removes the need for wear protection coating by eliminating the root cause of wear through the articulated joint design. By preventing transverse forces at the axial guidance, the harmful factor (wear) is eliminated, making the protective coating unnecessary and thus reducing production complexity and cost.
3Reliability
If higher tolerance demands are placed on coaxiality, then wear is reduced, but manufacturing precision requirements and cost increase
Solution Approach 1:
The articulated joint changes the mechanical parameters of the connection, transforming it from a rigid fixed-axis linkage to a flexible angular joint. This parameter change allows the system to function reliably with larger coaxiality tolerances, as the joint absorbs misalignment through its angular degrees of freedom rather than requiring precise coaxial alignment.
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 reduces mechanical stress on the piston guidance, eliminates the need for costly wear protection coatings, and allows for the use of more cost-effective spindle drives, thereby lowering production costs and improving the device's operational efficiency.
Implementation Method 1
an articulated joint between the piston and spindle includes a plug element and a pluck socket, which engage with each other while forming a frictional connection
Data Source
AI summary
A piston actuation device for the supply of a pressure medium in a pressure medium circuit of a brake system of a motor vehicle. A piston actuation device includes a piston actuable by a spindle drive to execute a back-and-forth translation movement in the direction of a piston guidance axis. The spindle drive has a spindle nut and a spindle that cooperates with the spindle nut via a screw drive. The screw drive converts a rotation movement of the spindle nut into a translation movement of the spindle in the direction of a spindle movement axis. To transmit the translation movement to the piston, the piston and the spindle are connected to each other in an axially fixed manner. The axially fixed connection between the piston and the spindle includes an articulated joint, which allows for a concentricity deviation between the piston guidance axis and the spindle movement axis.