Variable Displacement Pump Layout for Control Chamber Pressure Relief
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Solution Overview
Problem
In conventional variable displacement pumps, oil discharged from the discharge portion can flow into the control hydraulic chamber through side clearances, leading to high pressure in the chamber and potential suppression of desired oil supply to the internal combustion engine.
Innovation Solution
A first low pressure chamber is positioned to overlap with the discharge port between the pump accommodating portion and the adjustment ring in the radial direction, allowing oil to flow into this chamber via pressure differences, thereby preventing excessive pressure buildup in the control hydraulic chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If oil is discharged from the discharge portion, then oil supply to the internal combustion engine is enabled, but oil may flow into the control hydraulic chamber through side clearances causing high pressure that suppresses desired oil supply
Solution Approach 1:
The pump housing is divided into distinct pressure zones: a high-pressure discharge chamber and a low-pressure control hydraulic chamber separated by a partition wall. This segmentation prevents oil from the discharge portion from flowing into the control hydraulic chamber through side clearances, eliminating the pressure buildup problem while maintaining oil supply to the engine.
Solution Approach 2:
A communication hole is introduced as an intermediary controlled passage between the discharge portion and the control hydraulic chamber. This hole allows selective communication under specific pressure conditions, enabling the system to maintain reliable oil supply while preventing unwanted pressure transmission that would suppress desired oil flow.
2Ease of manufacture
If side clearances exist between pump housing and adjustment ring, then assembly and disassembly are facilitated, but oil leakage into control hydraulic chamber occurs
Solution Approach 1:
The harmful oil leakage path is extracted and isolated by introducing a partition wall that separates the discharge portion from the control hydraulic chamber. The partition wall with its controlled communication hole removes the uncontrolled leakage pathway through side clearances while preserving the ease of assembly by maintaining the adjustable ring structure.
Solution Approach 2:
The side clearances that originally caused harmful oil leakage are converted into a beneficial feature by introducing a partition wall with a communication hole. The communication hole allows controlled oil flow under specific conditions, transforming the potential leakage path into a regulated communication channel that maintains both assembly ease and prevents harmful leakage.
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 ensures stable oil supply to the internal combustion engine by managing pressure differentials and reducing the risk of oil supply suppression.
Implementation Method 1
a first low pressure chamber provided at a position that overlaps with a discharge portion between a pump accommodating portion and an adjustment ring in a radial direction of a pump structure with respect to a rotation axis of the pump structure, and the first low pressure chamber communicates with a low pressure portion that has pressure that is equal to or less than a hydraulic pressure of the oil discharged from the discharge portion
Data Source
AI summary
Discharge port (26) as arc-recessed discharge portion is formed by cutting on bottom surface (13a) of pump accommodating portion (13) of variable displacement pump. On mounting surface (1b) of housing body (1), first low pressure chamber (281) is formed at position overlapping with discharge port (26) in radial direction of pump structure (14) formed by driving shaft (3), rotor (4) and vanes (5) Drain hole (28b) communicating with low pressure portion located outside housing body (1) is formed on bottom surface (28a) of first low pressure chamber (281) along direction of rotation axis (O1) of pump structure (14). Low pressure portion has pressure that is hydraulic pressure of oil discharged from discharge port (26) or less. Oil from discharge port (26), having higher pressure than first low pressure chamber (281), flows into first low pressure chamber (281) by pressure difference between discharge port (26) and first low pressure chamber (281).