Assist Motor Hydraulic Circuit Layout to Prevent Cavitation
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Solution Overview
Problem
Hydraulic machines experience cavitation in energy recovery circuits when the flow rate of fluid is insufficient, leading to damage to assist motors and the overall machine, especially when the recovery function is turned off or during non-boom operations.
Innovation Solution
The hydraulic machine incorporates an anti-cavitation line connecting the outlet port and self-priming line, along with a drain valve on the second return line, to manage fluid flow and prevent cavitation by ensuring sufficient fluid flow to the assist motor, and includes a self-priming line to facilitate fluid circulation and maintain energy recovery efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the assist motor is driven by rotation of the drive shaft instead of providing torque-assistance, then the energy recovery function can be turned off or not used, but cavitation occurs due to insufficient fluid flow rate
Solution Approach 1:
The hydraulic circuit is divided into separate functional paths: an energy recovery path (recovery line) and a drive path (second return line). This segmentation allows the system to independently control fluid flow for energy recovery versus drive operation, preventing cavitation by ensuring the assist motor receives sufficient fluid through the recovery line even when the drive shaft rotates the motor.
Solution Approach 2:
A check valve is introduced as an intermediary component in the recovery line to prevent reverse flow of fluid from the first return line into the assist motor. This ensures unidirectional fluid flow and maintains sufficient pressure and flow rate to the assist motor, preventing cavitation while allowing the energy recovery function to be selectively activated or deactivated.
2Loss of energy
If the assist motor provides torque-assistance through energy recovery, then energy efficiency increases, but the system becomes vulnerable to cavitation when energy to be recovered is insufficient
Solution Approach 1:
The system pre-establishes a dedicated recovery line with proper fluid flow paths and check valves before energy recovery operations begin. This preliminary configuration ensures that when the energy recovery function is activated, sufficient fluid flow is already guaranteed to the assist motor, preventing cavitation before it can occur during high-efficiency energy recovery operations.
Solution Approach 2:
Different parts of the hydraulic system are given different functional qualities: the recovery line is optimized for energy recovery with check valves preventing reverse flow, while the second return line handles drive operations. This local differentiation ensures each path performs its specific function optimally without causing cavitation in the assist motor.
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
The solution effectively prevents cavitation and enhances energy recovery efficiency by ensuring continuous fluid flow to the assist motor, reducing damage and improving operational reliability in hydraulic machines.
Implementation Method 1
when the flow rate of fluid supplied to the assist motor is insufficient, cavitation may occur, thereby damaging not only the assist motor but also the entirety of the hydraulic machine
Implementation Method 2
a self-priming line connecting the first return line and the inlet port and configured to allow fluid to flow from the first return line to the inlet port
Implementation Method 3
A variety of hydraulic machines operating using hydraulic pressure are known in the art
Data Source
AI summary
A hydraulic machine includes: a power source; an assist motor including comprising an inlet port and an outlet port and assisting a torque of the power source; a tank; a collection line which is connected to the inlet port and allows a fluid to flow to the inlet port; a first return line which is connected to the tank and allows the fluid to flow to the tank; a self-priming line which connects the first return line to the inlet port and allows the fluid to flow from the first return line to the inlet port; and an anti-cavitation line which connects the outlet port to the self-priming line and allows the fluid to flow from the outlet port to the self-priming line.