Excavator Pilot Throttle Control for Boom Stop Swing Reduction
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Solution Overview
Problem
Shovels experience significant swinging of the vehicle body due to rapid changes in hydraulic pressure when stopping a rising boom, which is uncomfortable for operators and not adequately addressed by fixed throttle mechanisms.
Innovation Solution
A variable throttle mechanism is introduced in the pilot hydraulic circuit, controlled by a controller that adjusts its opening based on the operation state of the lever, slowing the return of the spool valves to neutral and reducing the impact of inertial loads, thereby minimizing vehicle body swinging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the operator returns the boom operation lever to neutral position rapidly to stop the boom, then the stopping response is fast, but the vehicle body swings in the turning direction causing operator discomfort
Solution Approach 1:
The patent applies dynamics by making the throttle opening variable rather than fixed. The controller dynamically adjusts the throttle opening degree based on operating conditions (turning state, boom/arm/bucket operations) to optimize the balance between stopping response speed and vehicle body stability. This resolves the contradiction by allowing the system to adapt its damping characteristics in real-time.
Solution Approach 2:
The patent changes the parameter of throttle opening degree from a fixed value to a variable parameter controlled by the controller. By adjusting this parameter according to different operating states (e.g., larger opening during turning to reduce swinging, smaller opening when not turning for faster response), the system resolves the contradiction between fast stopping and vehicle body stability.
2Object-affected harmful factors
If a fixed throttle mechanism is used to prevent rapid spool return, then the vehicle body swinging is reduced, but the mechanism cannot sufficiently prevent swinging under various operating conditions
Solution Approach 1:
The patent replaces the static fixed throttle mechanism with a dynamic variable throttle mechanism. The controller continuously monitors operating conditions (turning state, hydraulic pressures, arm/bucket operations) and adjusts the throttle opening accordingly, providing adaptability across all operating scenarios while maintaining vehicle body stability.
Solution Approach 2:
The system implements feedback control by monitoring the turning state and other operating parameters, then using this information to adjust the throttle opening degree. This closed-loop control ensures optimal performance under various conditions, resolving the limitation of fixed throttle mechanisms that cannot adapt to changing operating states.
3Object-affected harmful factors
If the throttle opening is reduced to slow spool return, then the vehicle body swinging is minimized, but the boom stopping response becomes slower
Solution Approach 1:
The variable throttle mechanism dynamically adjusts the opening degree based on real-time operating conditions. During turning operations, the throttle opening is reduced to minimize vehicle body swinging. When not turning or under different conditions, the opening is increased to maintain fast stopping response, thus resolving the time-loss contradiction through adaptive control.
Solution Approach 2:
The system changes the throttle opening parameter dynamically rather than maintaining a constant small opening. The controller adjusts this parameter based on turning state and other operations, allowing the system to achieve both fast stopping (when appropriate) and minimal swinging (when turning), resolving the contradiction between response time and stability.
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 implementation of a variable throttle in the pilot hydraulic circuit effectively reduces the swinging of the vehicle body, enhancing operator comfort by smoothing the deceleration of the boom and maintaining control during complex operations.
Implementation Method 1
a variable throttle 64 whose opening varies in accordance with a state of the operation of the operation lever, and a controller 30 configured to change the opening of the variable throttle 64
Implementation Method 2
a pilot circuit configured to control a pilot pressure in accordance with an operation of an operation lever, a hydraulic control valve configured to control the hydraulic oil supplied from the hydraulic pump to the hydraulic cylinder in accordance with the pilot pressure supplied from the pilot circuit
Data Source
Figure 1
Figure 2
Figure 3(a)~3(c)
AI summary
A turning body (3) of a shovel is driven to turn by a turning hydraulic motor (21B) driven with hydraulic oil supplied from a hydraulic pump (14). A hydraulic cylinder (7) is driven with the hydraulic oil supplied from the hydraulic pump (14). A pilot circuit controls a pilot pressure in accordance with the operation of an operation lever. A hydraulic control valve (17) controls the hydraulic oil supplied from the hydraulic pump (14) to the hydraulic cylinder (7) in accordance with the pilot pressure. A variable throttle (64) whose opening varies in accordance with the operating state of the operation lever (26A) is provided in the pilot circuit.