Variable Orifice Hydraulic Circuit for Crawler Speed Stability
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Solution Overview
Problem
Conventional hydraulic circuits for crawler type heavy equipment experience abrupt changes in traveling speed when operating both traveling and working devices simultaneously, leading to reduced manipulability and potential operator errors due to uneven hydraulic fluid distribution.
Innovation Solution
Incorporating a variable orifice in the confluence passage and a mode selection device, along with a controller to manage signal pressures and flow rates, ensures that hydraulic fluid is intercepted from the working device to the traveling device when the working device's load pressure exceeds the traveling device's, preventing abrupt speed changes and allowing for controlled flow adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If hydraulic fluid is supplied to both traveling device and working device simultaneously from separate pumps, then both devices can operate at the same time, but the traveling speed decreases abruptly due to insufficient hydraulic fluid supply to the traveling motors
Solution Approach 1:
The patent merges the hydraulic fluid supply paths by introducing a confluence passage that combines fluid from the first pump (dedicated to traveling device) and the second pump (dedicated to working device). This allows hydraulic fluid to be supplied to both traveling motors through a unified path, ensuring sufficient fluid supply maintains traveling speed while enabling simultaneous operation of both devices
Solution Approach 2:
The confluence passage acts as an intermediary element that receives hydraulic fluid from both the first and second pumps, then distributes it to the traveling motors. This mediator structure enables coordinated supply of hydraulic fluid to multiple actuators, resolving the conflict between simultaneous operation and maintaining traveling speed
2Speed
If a fixed orifice is installed in the confluence passage to supply hydraulic fluid to the traveling device, then traveling speed reduction is prevented, but the system lacks flexibility to adapt to different operating conditions
Solution Approach 1:
The patent replaces the fixed orifice with a variable orifice whose opening area can be dynamically adjusted based on operating conditions. This dynamic element allows the system to adapt the amount of hydraulic fluid supplied to the traveling device according to real-time requirements, maintaining traveling speed while providing flexibility for different operating scenarios
Solution Approach 2:
The variable orifice changes the flow resistance parameter dynamically, allowing the system to adjust the flow rate of hydraulic fluid to the traveling device based on operating conditions. This parameter change enables the system to maintain optimal traveling speed across varying operational requirements
3Speed
If the variable orifice opens to supply hydraulic fluid to the traveling device, then traveling speed is maintained, but the working device may not operate properly when its load pressure is high
Solution Approach 1:
The patent incorporates pressure sensors that detect the load pressure of the working device and provide feedback to the controller. When the working device's load pressure exceeds a predetermined threshold, the controller adjusts the variable orifice to close, preventing hydraulic fluid from being diverted to the traveling device. This feedback mechanism ensures the working device receives sufficient hydraulic fluid under high load conditions while maintaining traveling speed under normal conditions
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 solution stabilizes the traveling speed, reducing operator-induced errors and enhancing equipment safety by maintaining consistent performance during combined operations.
Implementation Method 1
a variable orifice installed in a confluence passage for connecting in parallel a flow path branched from the upstream side of the second center bypass passage and the second center bypass passage, and shifted in response to signal pressure formed in a control valve, in a working mode for simultaneously operating the traveling device and the working device, to intercept the supply of hydraulic fluid, being supplied to the working device, toward the traveling device through the confluence passage if load pressure generated in the working device is higher than load pressure generated in the traveling device
Implementation Method 2
a control valve, and a variable orifice installed in a confluence passage... shifted in response to signal pressure formed in a control valve
Implementation Method 3
a straight traveling valve installed on an upstream side of the second center bypass passage, and shifted in response to signal pressure supplied from a pilot pump, in a working mode for simultaneously operating the traveling device and the working device, to supply hydraulic fluid fed from the first hydraulic pump to switching valves for left and right traveling motors
Data Source
AI summary
A traveling device for crawler type heavy equipment is provided, which can improve manipulability by preventing an abrupt decrease/increase of a traveling speed of the equipment when a combined operation, in which a left/right traveling device and a working device are simultaneously driven, is performed. The traveling device for crawler type heavy equipment includes a variable orifice shifted to intercept the supply of the hydraulic fluid toward the traveling device in response to the signal pressure in the combined working mode if a load pressure of the working device is relatively higher than that of the traveling device.