Excavator Hydraulic Pump Layout for Concurrent Boom-Arm Control
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Solution Overview
Problem
Conventional hydraulic excavator drive systems require three solenoid proportional valves, which increases costs and complexity, while they aim to prevent excessive hydraulic oil flow into arm and boom cylinders with differing load pressures during concurrent operations.
Innovation Solution
The system incorporates a boom main control valve, a boom auxiliary control valve, an arm main control valve, and an arm auxiliary control valve, with a check valve on the boom raising second supply line to prevent reverse flow, allowing the first pump to be dedicated to the boom cylinder and the second pump to the arm cylinder, reducing the number of solenoid proportional valves needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If three solenoid proportional valves are used to control boom and arm auxiliary control valves, then the hydraulic system can prevent excessive oil flow to low-pressure cylinders, but the system cost and complexity increase
Solution Approach 1:
The invention extracts the solenoid proportional valve control mechanism from the boom auxiliary control valve, leaving only the arm auxiliary control valve with solenoid proportional valve control. The boom auxiliary control valve is instead controlled by a simple pilot pressure signal from the boom operation device, eliminating the need for a dedicated solenoid proportional valve while maintaining the ability to prevent excessive oil flow through pressure-based control logic
Solution Approach 2:
The pilot pressure signal from the boom operation device serves multiple functions: it controls both the boom main control valve and the simplified boom auxiliary control valve. This multi-functionality allows the same pressure signal to coordinate both primary and auxiliary boom operations without requiring separate electronic control components
2Adaptability or versatility
If three solenoid proportional valves are used for auxiliary control valves, then concurrent boom and arm operations can be controlled, but the manufacturing cost increases
Solution Approach 1:
The invention removes one solenoid proportional valve from the system by extracting its control function from the boom auxiliary control valve. The cost of manufacturing is reduced while the adaptability for concurrent operations is maintained through the simplified pressure-based control mechanism that uses existing pilot pressure signals
Solution Approach 2:
The boom auxiliary control valve is designed to automatically respond to pilot pressure signals from the boom operation device without requiring active electronic control. This self-service mechanism uses the inherent pressure characteristics of the hydraulic system to achieve coordinated control during concurrent operations
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 effectively prevents excessive hydraulic oil flow into the arm and boom cylinders at a lower cost by optimizing pump usage based on load pressures, reducing the number of solenoid proportional valves required and minimizing energy wastage.
Implementation Method 1
The boom raising second supply line is provided with a check valve that allows a flow from the boom auxiliary control valve toward a head side of the boom cylinder, but prevents a reverse flow
Data Source
AI summary
A hydraulic excavator drive system includes: a first pump connected to a boom main control valve and an arm auxiliary control valve by a first pump line; a second pump connected to a boom auxiliary control valve and an arm main control valve by a second pump line; and a controller that does not move the arm auxiliary control valve when arm crowding operation boom raising operations are performed concurrently. The boom auxiliary control valve moves together with the boom main control valve when the boom raising operation is performed. A boom raising second supply line, which connects the boom auxiliary control valve to a boom raising first supply line between the boom main control valve and a boom cylinder, is provided with a check valve that allows a flow from the boom auxiliary control valve toward a head side of the boom cylinder, but prevents a reverse flow.