Brake System Push Rod Diameter and Retainer Design
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Solution Overview
Problem
The conventional brake system experiences high surface pressure between the push rod and piston, leading to recess formation on the piston surface due to the inherent design of the check valve mechanism, which results in potential durability issues and increased production costs.
Innovation Solution
The design is modified to increase the diameter of the push rod end contacting the piston, incorporating a recessed portion in the seat member and a retainer with a sliding hole to support the push rod, allowing for reduced surface pressure and improved assembly processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the push rod diameter at the piston end is increased, then the surface pressure between push rod and piston is reduced, but the assembly process becomes more complex due to the need for additional components
Solution Approach 1:
A retainer component is introduced as an intermediary element between the push rod and the seat member. The retainer includes a sliding hole that receives the push rod, and it is fixed to the seat member at the recessed portion. This intermediary structure enables the push rod to have a larger diameter at its piston-end while maintaining proper assembly and functional relationships with other components.
2Reliability
If the push rod diameter at the piston end is increased, then durability is improved by preventing recess formation, but manufacturing cost increases
Solution Approach 1:
The retainer serves as a cost-effective intermediary solution that enables the use of a larger diameter push rod without proportionally increasing manufacturing costs. By distributing the structural requirements across multiple simpler components (retainer, sliding hole, recessed portion) rather than requiring a completely redesigned push rod, the solution achieves improved durability while controlling production costs.
3Shape
If the connecting opening inner diameter is larger at the ball valve element side, then the ball valve element can be properly positioned, but the push rod diameter at the piston end must be smaller
Solution Approach 1:
The connecting opening is segmented into different diameter sections: a larger diameter portion at the ball valve element side for proper valve positioning, and a smaller diameter portion at the piston side that accommodates the push rod. The retainer is positioned at the recessed portion to bridge these diameter transitions and provide structural support for the larger diameter push rod end.
Solution Approach 2:
The retainer acts as an intermediary structure that resolves the conflict between the larger diameter requirement at the ball valve side and the push rod diameter requirement at the piston side. It provides a mounting location that allows the push rod to maintain optimal diameter throughout its length while accommodating the varying connecting opening dimensions.
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 modification reduces surface pressure between the push rod and piston, preventing recess formation and enhancing durability while simplifying the assembly process and reducing production costs.
Implementation Method 1
a synthetic resin piston that is slidably received in the cylinder and biased by a coil spring in a direction to reduce the volume of the cylinder
Implementation Method 2
a valve spring that biases the ball valve element toward the valve seat
Implementation Method 3
a check valve mechanism that is provided at an upper part of the cylinder to control the brake liquid existing between the master cylinder and a liquid pressure chamber of the cylinder
Data Source
AI summary
[Summary] To provide a brake system in which due to change in structure of a seat member, an end portion of a push rod that faces a piston can be increased in diameter and thus weight reduction of entire construction of the piston and suppression of vibration hitting noises are obtained.A seat member 27 of a check valve mechanism 25 is formed at a position opposite to one open end of a connecting hole 27a with a recessed portion 27d that is opened to a liquid pressure chamber 20b, a retainer 31 that has at its center part a sliding hole 31c for slidably supporting the push rod 32 is fixed to an open side of the recessed portion, an annular part of the retainer is formed with an arcuate and elongate passage hole 31e for communicating the recessed portion with the liquid pressure chamber, a smaller diameter rod part 32a of the push rod, which is arranged at the side of the ball valve body 29, is inserted from the sliding hole toward a ball valve body through the recessed portion and the connecting hole, and a larger diameter rod part 32b of the push rod, which is kept inserted toward the ball valve body is slidably supported by the sliding hole.