Hydraulic Steering Backup Using a Cooling Fan Pump
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Solution Overview
Problem
Modern agricultural tractors face challenges with increasing complexity and costs due to the growing number of hydraulic pumps required to supply various consumers, including steering systems and cooling fans, which also reduces efficiency and increases installation space requirements.
Innovation Solution
A pressurized fluid supply system for agricultural vehicles that incorporates a main supply pump, a cooling fan pump, and an emergency steering pump, with a prioritization valve that allows the cooling fan pump to act as a secondary pump for the steering system, reducing the number of pumps needed and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of pumps is increased to supply various hydraulic consumers, then the reliability and capability of supplying pressurised fluid to steering system and cooling fan is improved, but the device complexity, installation space and costs increase
Solution Approach 1:
The cooling fan pump is designed to perform dual functions: it supplies pressurised fluid to the cooling fan motor during normal operation, and can be redirected via the prioritisation valve to supply the steering system when needed. This multi-functionality eliminates the need for a separate emergency steering pump, reducing the total number of pumps from three to two while maintaining steering reliability.
2Productivity
If the number of pumps is increased to supply various hydraulic consumers, then the capability of meeting hydraulic demand is improved, but the installation space required increases
Solution Approach 1:
By making the cooling fan pump universal (capable of serving both cooling and steering functions), the patent reduces the total pump count from three to two, thereby freeing up installation space on the agricultural vehicle while maintaining adequate hydraulic supply capability for all consumers.
3Reliability
If the number of pumps is increased to supply various hydraulic consumers, then the ability to meet hydraulic demand is improved, but the costs increase
Solution Approach 1:
The patent reduces system cost by eliminating the need for a dedicated emergency steering pump. Instead, the cooling fan pump is made universal with the addition of a prioritisation valve, allowing it to provide backup steering supply. This reduces the number of pumps from three to two, lowering manufacturing and acquisition costs while maintaining steering reliability.
4Adaptability or versatility
If the number of pumps is increased in the fluid supply system, then the capability of supplying various consumers is improved, but the efficiency decreases as each pump circulates oil even when demand is zero
Solution Approach 1:
The patent implements dynamic flow distribution through the prioritisation valve, which automatically directs fluid from the cooling fan pump to either the cooling fan motor or the steering system based on real-time pressure conditions. This dynamic switching eliminates the need for multiple continuously operating pumps, reducing energy waste from unnecessary circulation while maintaining supply flexibility.
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 reduces the number of pumps required, thereby lowering costs and improving installation space efficiency while maintaining continuity of supply for the steering system, ensuring safety and efficiency in fluid supply.
Implementation Method 1
the prioritisation valve being configured to adopt a first operative configuration in which fluid flow from the cooling fan pump to the cooling fan motor through the prioritisation valve is substantially unrestricted when the pressure in the steering circuit is at or above a first threshold value and to adopt a second operative configuration in which fluid flow from the cooling fan pump to the cooling fan motor through the prioritisation valve is partially restricted when the pressure in the steering circuit is below the first threshold value
Implementation Method 2
one of the cooling fan pump and the cooling fan motor is a variable displacement machine, the fluid supply system having a control system operative to adjust displacement of the variable displacement machine to maintain the input drive power provided by the cooling fan motor to the cooling fan substantially constant or at a demanded value and/or to vary the speed of the fan in accordance with cooling demand
Data Source
Figure 1
Figure 2
AI summary
In a hydraulic system (10) for a tractor, a main pump (12) supplies fluid to a steering system (22) through a steering circuit (24) and a second pump (14) supplies fluid to a cooling fan motor (42). The second pump is connected with the steering circuit to provide a second a source of fluid to the steering system when the main pump is unable to meet demand. A prioritisation valve (48) regulates the flow of fluid from the second pump to the motor. The valve has a first operative configuration (48a) in which fluid flow from the second pump to the motor is unrestricted and a second operative configuration (48b) in which fluid flow from the second pump to the motor is blocked or restricted. The valve adopts the second operative configuration when the pressure in the steering circuit is below a first threshold value. The second pump acts as a secondary pump for the steering system and drives a cooling fan.