Hydraulic Valve Unit With Rapid Traverse and Preload Locking
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Solution Overview
Problem
Existing hydraulic systems for telescopic booms in mobile cranes face issues such as undesired extension due to pressure buildup in pipe feedthroughs, increased telescoping times, and inefficiencies in telescoping speed, leading to higher costs, weight, and power losses.
Innovation Solution
A hydraulic system with a valve unit integrating a rapid traverse device and preload means, allowing hydraulic fluid to be interconnectable or separable between pressure chambers, and a switchable preload element to prevent undesired extensions, while optimizing telescoping speed and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a control block is added to switch the preload, then the preload can be switched on and off, but costs, weight, installation space, and complexity increase
Solution Approach 1:
The patent combines the preload control function with the existing control valve that manages the hydraulic cylinder. The control valve is configured to selectively connect the second pressure chamber to either the hydraulic pump or the hydraulic tank, thereby integrating the preload switching function into the existing control system without adding a separate control block. This reduces component count and system complexity while maintaining the ability to prevent undesired extension.
2Productivity
If telescoping speed is increased, then productivity improves, but power losses and energy consumption increase
Solution Approach 1:
The patent implements dynamic control of the telescoping process by using the control valve to regulate hydraulic fluid flow to the pressure chambers. The control valve can adjust the rate at which hydraulic fluid enters the first pressure chamber and exits the second pressure chamber, allowing optimization of telescoping speed while managing power losses. This dynamic control enables faster telescoping when needed while reducing energy consumption during normal operation.
3Ease of operation
If a pipe feedthrough is used in the piston rod, then hydraulic supply to the locking device is enabled, but pressure buildup causes undesired extension
Solution Approach 1:
The patent introduces the control valve as an intermediary component between the hydraulic pump and the second pressure chamber. The control valve selectively connects or disconnects the second pressure chamber from the hydraulic pump and hydraulic tank, thereby mediating the pressure supply to prevent unwanted extension while maintaining hydraulic supply functionality. This intermediary control mechanism allows the system to benefit from the pipe feedthrough configuration without suffering from its harmful effects.
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 system achieves faster telescoping times, reduces weight and costs, and minimizes power losses by integrating a compact valve unit with rapid traverse and preload functions, enhancing operational efficiency and reducing operator distraction.
Implementation Method 1
a double-acting hydraulic cylinder (20) having a first and a second pressure chamber (21, 22), to which pressure can be applied via a hydraulic pump (12) in order to move a piston (24) of the hydraulic cylinder (20)
Implementation Method 2
a rapid traverse device which is configured to hydraulically interconnect the two pressure chambers (21, 22) in a rapid traverse mode, such that hydraulic fluid displaced out of one pressure chamber can flow into the other pressure chamber
Implementation Method 3
Both the driving pins and the yoke are preloaded into their locking positions via spring elements
Data Source
AI summary
The disclosure relates to a hydraulic system for pressure supply of a hydraulic actuator, comprising a double-acting hydraulic cylinder having two pressure chambers, and a rapid traverse device integrated into a valve unit and configured to hydraulically interconnect the two pressure chambers in a rapid traverse mode and hydraulically separate the two pressure chambers in a normal traverse mode. The valve unit connects to the pressure chambers via first and second connections and comprises a third connection for applying pressure via a hydraulic pump. A displaceably mounted shift piston separates the first and second connections in normal traverse position and connects them, separated from the third connection, in rapid traverse position. The valve unit integrates a preload device having a switchable preload element configured to separate the third connection from the second connection in a locking position, thereby locking the pressure chamber connected to the second connection towards the outside.