Cam Ring Spring Stop for Stable Variable Oil Pump Assembly
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Solution Overview
Problem
The conventional variable displacement oil pump faces difficulty in installing the coil spring due to the necessity of fitting a projection to the inner periphery of the coil spring, which complicates the installation process.
Innovation Solution
A projection is formed on the cam ring extending in the longitudinal direction of the coil spring, overlapping with the outer periphery, facilitating easier installation by avoiding interference with the inner periphery during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the projection is fitted to the inner periphery of the coil spring, then the coil spring position shift is suppressed, but the installation difficulty increases
Solution Approach 1:
The patent inverts the conventional design by having the projection overlap with the outer periphery of the coil spring rather than fitting into the inner periphery. This inversion allows the coil spring to be installed without complex fitting operations while still achieving position stability through the projection's overlap with the outer periphery, thus resolving the contradiction between position stability and installation ease
2Reliability
If the projection is formed to fit the inner periphery of the coil spring, then the coil spring position shift is suppressed, but the installation time increases
Solution Approach 1:
By inverting the conventional design where the projection overlaps with the outer periphery of the coil spring rather than fitting into the inner periphery, the patent enables rapid installation without time-consuming fitting operations. The position stability is maintained through this inverted configuration, simultaneously resolving the contradiction between position stability and installation time
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 configuration effectively suppresses position shift of the coil spring while ensuring ease of installation, enhancing the overall assembly process.
Implementation Method 1
The coil spring exerts bias force that biases the cam ring in a direction to increase an amount of eccentricity of the cam ring
Data Source
AI summary
A variable displacement oil pump according to the present invention has a protrusion (46) that is partially formed on a spring contact surface (451) of an arm part (45) of a cam ring (4) so as to overlap with part of the outer circumference of a coil spring (SP). This protrusion (46) restricts tilting of the coil spring (SP) and makes it possible to suppress positional deviation of the coil spring (SP). Furthermore, because the protrusion (46) is provided partially on the spring contact surface (451) of the arm part (45) of the cam ring 4, the coil spring (SP) need only be pushed inward of the protrusion (46) when installing the coil spring (SP), thus making it possible to ensure ease of installation of the coil spring (SP).