Vaned Pump Cam Ring Eccentricity Control Without Spring
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Solution Overview
Problem
Conventional pump devices require a spring to bias the cam ring, leading to structural complexity and increased component count.
Innovation Solution
A pump device where the cam ring moves rollingly on a cam supporter surface due to pressure differences between fluid pressure chambers, eliminating the need for a spring by forming the cam ring with an eccentricity-increase-side angle greater than the eccentricity-decrease-side angle, allowing it to self-bias and adjust its eccentricity based on internal pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a spring is used to bias the cam ring in conventional pump devices, then the cam ring can be biased to increase displacement, but the structural complexity increases due to the need for a container space for the spring
Solution Approach 1:
The invention extracts and eliminates the spring component from the pump device by replacing it with a biasing force generated through fluid pressure acting on the cam ring. The cam ring is designed with an asymmetric cross-sectional shape that allows fluid pressure to create a biasing force without requiring a separate spring container space, thus removing the spring while maintaining the necessary biasing function.
Solution Approach 2:
The invention uses hydraulic principles by introducing fluid pressure chambers (first and second fluid pressure chambers) that act on the cam ring to generate the biasing force. The asymmetric cross-section of the cam ring is designed to convert fluid pressure into a directional biasing force, replacing the mechanical spring system with a hydraulic/pneumatic system that eliminates the need for spring housing.
2Device complexity
If the cam ring is designed with asymmetric angles (eccentricity-increase-side angle greater than eccentricity-decrease-side angle), then the spring can be eliminated, but the manufacturing precision requirements increase
Solution Approach 1:
The invention changes the geometric parameters of the cam ring by designing an asymmetric cross-sectional shape with specific angle relationships (eccentricity-increase-side angle greater than eccentricity-decrease-side angle). This parameter change allows the cam ring to generate biasing force through fluid pressure acting on its asymmetric surfaces, eliminating the need for a spring while the angles are designed within manufacturable ranges to balance precision requirements with functional performance.
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
Simplifies the structure by eliminating the need for a spring, reducing component count and facilitating efficient hydraulic fluid discharge without leakage, while maintaining optimal pump performance.
Implementation Method 1
the cam ring is structured to be movable in a pump element container space rollingly on a cam supporter surface, due to a pressure difference between a first fluid pressure chamber and a second fluid pressure chamber and due to a pressure of hydraulic fluid in a discharge region
Data Source
AI summary
A cam ring is capable of moving while rolling on a cam support surface. The cam ring is provided such that within a range in which the cam ring can move on the cam support surface, an eccentricity amount increasing-side angle is always greater than an eccentricity amount decreasing-side angle. On a plane perpendicular to the rotation axis of a driving shaft, the eccentricity amount increasing-side angle is an angle, in a direction opposite to a rotation direction of the driving shaft, from a first reference line, which connects a tangent point between the cam ring and the cam support surface to a rolling center of the cam ring, to a starting end of a first discharge port. The eccentricity amount decreasing-side angle is an angle, in the rotation direction of the drive shaft, from the first reference line to a terminal end of the first discharge port.