Rotating Swash Plate Piston Pump for Low-Friction Variable Displacement
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Solution Overview
Problem
Conventional variable displacement piston pumps experience issues such as wear, friction, and mechanical damage due to the interaction between piston shoes and a rotationally fixed swash plate, which are exacerbated by high fuel temperatures and pressures, leading to efficiency losses and increased failure risk.
Innovation Solution
A straight axis variable displacement piston pump design where the swash plate and piston barrel are rotationally coupled to a common drive shaft, minimizing friction through a keyway design and using tapered roller bearings to transfer axial loads, allowing the swash plate to pivot relative to the drive shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the swash plate is rotationally fixed relative to the piston barrel, then the pump structure is simpler, but friction and wear between piston shoes and swash plate increase significantly
Solution Approach 1:
The patent merges the rotational motion of the swash plate with the piston barrel by coupling both to a common drive shaft. This causes the swash plate and piston barrel to rotate together at the same speed, eliminating the continuous sliding friction between piston shoes and swash plate while maintaining the variable displacement function through swash plate tilt angle adjustment.
2Ease of manufacture
If the swash plate is rotationally fixed, then manufacturing and assembly are easier, but heat generation from friction increases
Solution Approach 1:
By rotating the swash plate with the piston barrel at the same speed, the relative motion between piston shoes and swash plate is minimized to only the necessary reciprocating movement, dramatically reducing frictional heat generation while maintaining straightforward manufacturing and assembly of the coupled rotation system.
3Strength
If the swash plate is stationary, then the design is more robust structurally, but uneven loading and localized stress increase
Solution Approach 1:
The coupled rotation of the swash plate with the piston barrel ensures that the swash plate remains dynamically balanced during operation. This eliminates uneven loading and localized stress concentrations that would occur with a stationary swash plate, while the overall structural robustness is maintained through the integrated design.
4Device complexity
If the swash plate is fixed, then alignment is simpler, but mechanical damage from impact loads and vibration increases
Solution Approach 1:
By coupling the swash plate rotation to the piston barrel rotation, the system eliminates misalignment between these components. They rotate together as a synchronized unit, preventing the impact loads and vibrations that would occur with a fixed swash plate, thereby reducing mechanical damage while maintaining alignment simplicity.
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 design reduces friction and heat generation, enhancing the pump's robustness and efficiency at higher fuel temperatures and pressures, while maintaining effective operation.
Implementation Method 1
The interaction between the swash plate and the piston shoes can pose several issues including but not limited to wear caused by friction, uneven loading and localized stress caused by misalignment, heat generation from friction
Implementation Method 2
minimizing friction through a keyway design
Data Source
AI summary
An axial variable displacement piston pump includes a drive shaft disposed on an axis, a piston barrel comprising a plurality of pistons disposed about the drive shaft, and a swash plate disposed about the drive shaft. Each of the piston barrel and the swash plate are rotationally coupled to the drive shaft such that the drive shaft is configured to simultaneously drive rotation of each of the piston barrel and the swash plate.