Master Cylinder Piston Rod Retention via Segmented Stop Ring
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Solution Overview
Problem
Existing methods for securing the piston rod in a master cylinder require significant installation space and complex tooling, leading to quality issues and contamination due to the formation of burrs during assembly.
Innovation Solution
A stop ring with a bore and flattened areas is used to secure the piston rod, connected to the cylinder housing in a materially bonded and force-fitting manner, allowing for axial movement limitation and reducing installation space, while a locking ring and scraper ring enhance security and prevent dirt entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a retaining clip connection is used to secure the piston rod in the master cylinder, then the piston rod can be retained, but significant installation space is required in the axial direction and the housing tool becomes more complex
Solution Approach 1:
The housing is divided into two separate components: the cylinder housing and the stop ring. The stop ring is a detachable component that can be produced with a simple tool and then attached to the housing, separating the complex retaining clip function from the simple cylindrical housing geometry.
Solution Approach 2:
The stop ring acts as an intermediary component between the housing and the piston rod. It provides the complex retention geometry needed for securing the piston rod while keeping the housing itself simple and easy to manufacture.
2Reliability
If a retaining clip connection is used to secure the piston rod, then the piston rod can be retained, but burrs form during assembly leading to contamination and quality problems
Solution Approach 1:
Instead of forming complex retaining features directly in the housing that require tearing or shearing during assembly, the stop ring is designed as a separate component with pre-formed retention features that engage smoothly, eliminating the burr-forming process.
3Length of moving object
If the stop ring is connected to the cylinder housing in a materially bonded and force-fitting manner, then axial installation space is minimized, but the connection strength must be sufficient
Solution Approach 1:
The connection between the stop ring and housing uses a combination of material bonding (adhesive) and force-fitting (mechanical interference), creating a composite connection that achieves both compact dimensions and high strength.
Solution Approach 2:
The connection interface between the stop ring and housing is designed with localized features (such as tapered surfaces or interference-fit zones) that concentrate the bonding and mechanical strength in specific areas, maximizing connection strength while minimizing overall axial space.
Data Source
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AI summary
The invention relates to an arrangement and method for securing an actuating rod system of an actuating pedal in a motor vehicle. The arrangement comprises a master cylinder, on one end of which a stop ring and a securing ring are provided, in order to secure a piston rod with a foot inside a cylinder housing by means of a piston. To this end the foot and the piston rod can extend through substantially central bores of the stop ring and the securing ring. After twisting of the piston rod relative to the stop ring and a further twisting of the stop ring relative to the piston rod, the piston rod is located in a latched position relative to the stop plate, which is additionally secured by the securing ring, even in the event of possible twisting of the piston rod.