Stepped Roller Vane Hydraulic Machine
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Solution Overview
Problem
Hydraulic devices with standard vanes face limitations due to rubbing force restrictions between the vane tip and ring contour, leading to potential failure under high speed and pressure conditions, which affects power density and operational life.
Innovation Solution
The implementation of hydrostatically lubricated roller bearings in hydraulic devices with stepped roller vanes, allowing the roller to rotate freely and be retained by the vane main body, eliminating direct contact with the ring contour and enabling higher pressure operation without reducing power density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard vanes are used in hydraulic devices, then the structure is simple and easy to manufacture, but the rubbing force between vane tip and ring contour causes failure under high speed and pressure conditions
Solution Approach 1:
A roller is introduced as an intermediary element between the vane tip and the ring contour. The roller rotates freely on the vane tip while contacting the ring contour, converting direct sliding friction into rolling friction. This intermediary component eliminates the rubbing motion that causes failure, allowing the hydraulic device to operate reliably under high speed and pressure conditions.
Solution Approach 2:
The direct contact mechanical system between vane tip and ring contour is replaced with a roller-bearing system. The roller acts as a bearing that substitutes the sliding friction mechanism with a rolling friction mechanism, significantly reducing wear and improving operational life under demanding conditions.
2Stress or pressure
If vane tip contacts ring contour directly, then the device structure is simple, but rubbing motion occurs leading to failure under high pressure conditions
Solution Approach 1:
The roller serves as a mediator that protects the vane tip from direct contact with the ring contour under high pressure. By transferring the contact through the roller, the rubbing motion is eliminated, allowing the device to withstand higher operating pressures without failure.
3Reliability
If roller is added to eliminate rubbing motion, then operational life and pressure capability improve, but device complexity increases
Solution Approach 1:
The roller is designed as a simple cylindrical intermediary component that fits into a cavity in the vane tip. While it does add a component, its simple geometry and function (rotating freely on the vane tip) minimize the increase in overall device complexity while delivering significant improvements in operational life and pressure capability.
4Strength
If roller is retained by vane main body, then vane integrity is maintained under high pressure, but manufacturing precision requirements increase
Solution Approach 1:
The roller is retained by the vane main body through a cavity and retaining structure. This design ensures the roller remains properly positioned under high pressure loads, maintaining vane integrity. The retaining mechanism requires precise manufacturing to ensure proper fit and function, but this precision ensures reliable roller retention under demanding operating conditions.
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 enhances operational life and power density by eliminating rubbing motion, allowing the hydraulic devices to operate effectively at higher pressures and maintaining vane integrity, while also providing operational flexibility as a starter motor, hydraulic coupling, or vane pump.
Implementation Method 1
a roller bearing which removes the rubbing motion between the vane and the ring contour
Implementation Method 2
the roller can be fed pressurized oil between the roller surface and the vane main body to create a hydrostatic bearing
Implementation Method 3
the vane tip penetrates the oil film that lubricates between the tip and the ring
Data Source
Figure 1
Figure 1A
Figure 1B
AI summary
Various designs for hydraulic devices are disclosed including hydraulic devices that can include a rotor, vanes and a ring. The rotor can be disposed for rotation about an axis. The plurality of vanes can each include a vane step. Each of the plurality of vanes can be moveable relative to the rotor between a retracted position and an extended position where the plurality of vanes work a hydraulic fluid introduced adjacent the rotor. A roller can be mounted to a tip of each of the plurality of vanes. The ring can be disposed at least partially around the rotor. The rotor can include one or more passages for ingress or egress of a hydraulic fluid to or from a region adjacent the vane step and defined by at least the rotor and the vane step.