Pivoting Push Pin Piston Assembly for Low-Wear Reciprocation
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Solution Overview
Problem
Reciprocating assemblies experience inefficiencies due to forces applied to pistons being misaligned with the cylinder axis, leading to increased friction and wear, which can cause failure.
Innovation Solution
A piston assembly with a hollow center and a push pin received within, where the push pin pivots between in-line and angled positions to apply force substantially along the cylinder axis, reducing perpendicular components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If force is applied to the piston at an angle (via wobble plate mechanism), then reciprocating motion is achieved, but perpendicular force components increase friction and wear
Solution Approach 1:
The force application is segmented into two independent functions: the wobble plate provides reciprocating motion capability, while the push pin provides axial force alignment. This segmentation allows each component to specialize in one function, reducing the negative interaction between angled force application and frictional wear.
Solution Approach 2:
The push pin acts as an intermediary element between the wobble plate and piston. It receives the angled force from the wobble plate and converts it into axial force on the piston, mediating the force transmission to eliminate perpendicular components that cause wear.
2Productivity
If force is applied perpendicular to the cylinder axis, then piston motion is enabled, but frictional wear between piston and cylinder increases
Solution Approach 1:
The harmful perpendicular force component is extracted and eliminated from the system. The push pin is designed to transmit only axial forces to the piston, taking out the problematic lateral forces that cause frictional wear and improving component durability.
Solution Approach 2:
Instead of having the piston directly receive angled forces from the wobble plate, the force transmission path is inverted: the push pin first receives axial forces and then transfers them to the piston, reversing the traditional force application sequence to eliminate wear-causing components.
3Ease of operation
If greater resultant force is applied to overcome perpendicular components, then piston motion is maintained, but energy efficiency decreases
Solution Approach 1:
The push pin converts the potentially harmful angled force from the wobble plate into beneficial axial force on the piston. By redirecting the force vector through the push pin mechanism, the system transforms what would be wasted perpendicular force into useful work along the cylinder axis, improving energy efficiency.
Data Source
AI summary
A reciprocating assembly includes a bore that contains hydraulic fluid. A piston is received within the bore and can move within the bore in a reciprocating motion between an extended position and a retracted position. Displacement of the piston within the bore causes displacement of hydraulic fluid when hydraulic fluid is in the bore. The piston includes an internal cavity extending at least partially along a length of the piston. The reciprocating assembly also includes a push pin that is received within the internal cavity. The bore, piston, and push pin are arranged so that movement of the push pin related to the bore causes translation of the piston within the bore to the extended position along a translation axis. The push pin can pivot during movement of the push pin between an in-line position and an angled position. The in-line position is substantially parallel to the translation axis.