Excavator Float Valve Logic for Blade Leveling and Jacked-Up Stability
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Solution Overview
Problem
Construction machines, such as hydraulic excavators, face issues where the blade is inadvertently put into a float state during maintenance or jacking operations, leading to unintended lowering of the machine body, and struggle with effective leveling on rugged terrain due to misoperation of the blade control valve.
Innovation Solution
A construction machine equipped with a float valve, pressure sensor, and controller that determines the machine's state and controls the float valve to prevent the blade from floating when the machine is jacked up, while allowing it to float and perform leveling operations when not jacked up, ensuring the blade is not put into a float state during misoperation and enabling effective leveling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the blade control valve is configured with a float position to enable leveling work on rugged terrain, then the blade can follow the ground contour effectively, but the machine body may be inadvertently lowered during maintenance operations due to misoperation
Solution Approach 1:
The patent applies dynamics by making the float valve's operational state changeable based on machine conditions. The float valve is controlled to switch between a first state (enabling float mode for leveling) and a second state (disabling float mode during maintenance), allowing the system to adapt its behavior dynamically according to the operational context detected by the controller
Solution Approach 2:
The patent implements feedback through the controller that monitors machine state and automatically adjusts the float valve position accordingly. The controller receives information about the machine's operational mode and uses this feedback to prevent misoperation by disabling the float function when the machine is in maintenance position, while enabling it during normal leveling operations
2Ease of operation
If the blade is allowed to float during maintenance operations, then the blade can follow ground contours, but the machine body stability is compromised due to unintended lowering
Solution Approach 1:
The patent applies preliminary action by proactively controlling the float valve to the closed position when the machine is detected to be in maintenance position, before any misoperation can occur. This preliminary preventive action ensures that the blade cannot inadvertently float and cause machine body lowering, while still allowing float mode to be activated when appropriate for leveling work
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
Prevents the machine body from being lowered during jacking operations due to misoperation and allows for effective leveling on uneven ground by ensuring the blade is only in a float state when intended, enhancing operational safety and efficiency.
Implementation Method 1
a pressure sensor that detects a pressure in at least one of the bottom-side hydraulic chamber and the rod-side hydraulic chamber of the blade cylinder
Implementation Method 2
a blade cylinder that is operated by a hydraulic fluid delivered from a hydraulic pump and that drives the blade in the vertical direction
Implementation Method 3
a float valve that is provided in hydraulic lines communicating respectively with a bottom-side hydraulic chamber and a rod-side hydraulic chamber of the blade cylinder
Data Source
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AI summary
Provided is a construction machine that can prevent a machine body from being lowered since a blade is not put into a float state even where a misoperation is made by an operator when the machine body is in a jacked-up state, and that can perform a favorable leveling operation by putting the blade into the float state in accordance with an operator's operation when the machine body is not in the jacked-up state. A hydraulic excavator includes a controller 42 that determines whether or not the machine body is in a jacked-up state and controls a float valve 41. In the case where it is determined that the machine body is not in the jacked-up state, the controller 42 changes over the float valve 41 to a float position V and invalidates an operation of a blade control valve 22, in accordance with a float instruction. In the case where it is determined that the machine body is in the jacked-up state, the controller 42 holds the float valve 41 in a reference position IV and validates the operation of the blade control valve 22, irrespectively of the presence or absence of the float instruction.