Wheel Loader Hydraulic Flow Split for Stable Implement Drive
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Solution Overview
Problem
Construction machines, such as wheel loaders, face fluctuations in hydraulic fluid volume flow when operating additional devices simultaneously with main implements, leading to reduced speed or standstill, despite using two pumps to increase volume flow.
Innovation Solution
A construction machine with two pumps, where the first pump supplies the main volume flow to the hydraulic valve block for the working device and the second pump's output is connected to a priority valve that divides the volume flow, ensuring continuous supply to the working device while allowing flexible distribution to additional devices, reducing fluctuations and pressure peaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If two pumps are used to increase hydraulic fluid volume flow, then the volume flow rate is improved, but fluctuations in volume flow and pressure occur when auxiliary devices are operated
Solution Approach 1:
The hydraulic system is segmented into two independent pump circuits: a first pump dedicated to supplying the working device, and a second pump supplying auxiliary devices. This segmentation ensures that the working device receives consistent hydraulic fluid volume flow regardless of auxiliary device operation, eliminating flow rate fluctuations while maintaining high total system capacity.
2Adaptability or versatility
If auxiliary devices are operated simultaneously with main implements, then functional versatility is improved, but volume flow rate to the working device is reduced
Solution Approach 1:
The hydraulic system is divided into separate supply circuits: the first pump exclusively serves the working device while the second pump serves auxiliary devices. This allows both to operate simultaneously at full capacity without competing for the same hydraulic fluid volume flow, maintaining working device productivity while enabling auxiliary functionality.
Solution Approach 2:
The construction machine achieves multi-functionality by integrating both main working devices and auxiliary devices into the same hydraulic system architecture. The universal hydraulic platform supports diverse operations (working device plus one or more auxiliary devices) without compromising the performance of any individual function.
3Productivity
If all hydraulic fluid flow is directed to the working device, then productivity is improved, but auxiliary devices cannot be operated
Solution Approach 1:
The hydraulic system segments total pump capacity into dedicated supply lines: first pump output goes exclusively to the working device, while second pump output goes exclusively to auxiliary devices. This segmentation allows each function to receive its required flow independently, enabling the working device to operate at maximum productivity while auxiliary devices remain available when needed.
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 ensures a reliable drive for hydraulically driven working devices by maintaining a consistent hydraulic fluid supply, even when additional devices are operated, minimizing volume flow reductions and pressure fluctuations, and allowing flexible adjustment of volume flow distribution based on pressure ratios.
Implementation Method 1
a first pump (2) for conveying a hydraulic fluid, which is connected via an outlet to a hydraulic valve block (20) to drive the working device (21)
Implementation Method 2
a second pump (3) for conveying a hydraulic fluid, wherein an outlet of the second pump (3) is connected to a priority valve (4) for splitting a fluid flow
Implementation Method 3
The distribution of the volume flow rate at the priority valve is pressure-dependent
Implementation Method 4
The hydraulic valve block preferably has several sections, for example, series sections, each connected to an auxiliary device
Data Source
Figure 1
AI summary
A construction machine, in particular a wheel loader, comprises a motor (1); a first pump (2) for pumping a hydraulic fluid; a second pump (3) for pumping a hydraulic fluid; a hydraulically driven working device (21) supplied with a main flow rate; several hydraulically driven auxiliary devices, each supplied with a secondary flow rate; a hydraulic valve block (20) connected to an outlet of the first pump (2) and having several sections, wherein the hydraulic fluid can be supplied from the first pump (2) to the working device (21) via a first section, and the hydraulic fluid can be supplied to the auxiliary devices (22) via further sections, wherein an outlet of the second pump (3) is connected to a priority valve (11) for splitting the flow rate of the hydraulic fluid, which is connected to the working device (21) via a first line and to the hydraulic valve block (20) via a second line.Furthermore, the invention relates to a method for driving a work tool (21) and an additional device (22) on a construction machine.