Variable Displacement Oil Pump with Suction-Path Spring Clearance
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Solution Overview
Problem
The conventional variable displacement oil pump suffers from increased suction resistance due to the arm portion of the cam ring and coil spring overlapping the suction portion, which reduces the pump's suction performance.
Innovation Solution
The urging member is positioned between the pump accommodating portion and the adjusting member, facing the drive shaft in a radial direction, and is located to avoid overlapping the suction portion when viewed from the axial direction, thereby reducing suction resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the arm portion of the cam ring and coil spring are arranged to overlap the suction portion, then the urging force can be applied effectively to increase the eccentric amount, but the suction resistance increases and suction performance deteriorates
Solution Approach 1:
The patent repositions the coil spring from a radial arrangement (overlapping the suction portion) to an axial arrangement (behind the cam ring). This dimensional change allows the spring to maintain its urging force function while eliminating interference with the suction portion, thereby resolving the contradiction between applying sufficient urging force and avoiding increased suction resistance
2Force
If the arm portion extends to the outer side of the cam ring, then the urging force can be transmitted to increase the eccentric amount, but the structural complexity and space occupation increase
Solution Approach 1:
The patent extracts and eliminates the unnecessary arm portion that extended to the outer side of the cam ring. By removing this redundant structural element while maintaining the core function through direct spring-to-cam-ring contact, the design achieves simpler structure and reduced space occupation while preserving the urging force transmission capability
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 reduces suction resistance, improving the pump's suction performance.
Implementation Method 1
a coil spring forcing the cam ring in a direction in which an eccentric amount is increased by an urging force of the coil spring
Data Source
AI summary
In a variable displacement oil pump (VP1) according to the present invention, a coil spring (SP) as an urging member is arranged at a position that does not overlap a first suction port (114), a first discharge port (115) and an inlet (124a) which correspond to a suction portion when viewed from an axial direction along a drive shaft (2). Therefore, in the variable displacement oil pump (VP1), there is no risk that during pump operation, flow of oil introduced into the pump chambers 30 located in a suction region through the first suction port (114), the first discharge port (115) and the inlet (124a) corresponding to the suction portion will be interrupted by the coil spring (SP). With this, in the variable displacement oil pump (VP1), a suction resistance during the pump operation is reduced, then a suction performance of the pump can be improved.