Construction Machine Lock Valve Timing Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In construction machines, the simultaneous movement of multiple lock valves from a locking to an unlocking position causes hydraulic oil to flow into a large space, leading to shock and an unpleasant operator experience due to increased pressure loss and limited cross-sectional areas in hydraulic passages.
Innovation Solution
The construction machine incorporates a system where the valve elements of multiple lock valves move from the locking to the unlocking position at different times, controlled by varying biasing forces or electrical signals, ensuring sequential operation and reducing instantaneous flow space formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple lock valves are connected to control valves and hydraulic pumps, then the boom can be reliably locked during work suspension, but the cross-sectional area of hydraulic passages is limited causing increased pressure loss
Solution Approach 1:
The hydraulic system is divided into multiple independent control paths, each with its own control valve and lock valve. This segmentation allows each passage to maintain adequate cross-sectional area while still providing multiple control points for reliable locking of the boom during work suspension.
2Speed
If multiple lock valve elements move from locking to unlocking position simultaneously, then the boom can quickly respond to operation commands, but shock increases causing unpleasant operator feeling
Solution Approach 1:
The lock valve elements are designed to move sequentially rather than simultaneously. The control system activates each lock valve in sequence, creating a periodic action pattern that prevents sudden large-volume hydraulic oil flow and the associated shock, while still achieving quick overall response to operation commands.
3Loss of energy
If the cross-sectional area of hydraulic passages is increased to reduce pressure loss, then the valve body size increases, but the device complexity and size increase
Solution Approach 1:
Instead of using a single large passage, the system uses multiple smaller passages in parallel, each with adequate cross-sectional area. This segmentation maintains low pressure loss while keeping the valve body size and complexity manageable through modular design.
Data Source
AI summary
A hydraulic excavator includes control valves connected to a head-side chamber of a boom cylinder, an operating unit configured to switch the control valves, lock valves each provided between the head-side chamber and each of the control valves, and an operation control unit that controls the operation of the lock valves. The lock valves each have a valve element that is configured to move between a locking position at which the discharge of hydraulic oil from the head-side chamber is restricted and an unlocking position at which the discharge of the hydraulic oil from the head-side chamber is allowed. The operation control unit controls the operation of the lock valves so that the valve elements move from the locking position to the unlocking position at different points in time when the operating unit is operated.