Hydraulic Fluid Cooling System for Integrated Hydrostatic Transmissions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Zero turning radius mowers with individual integrated hydrostatic transmissions face challenges in managing hydraulic fluid temperature, particularly when operating on side slopes, as existing cooling solutions are costly, prone to plugging, and insufficient under severe conditions.
Innovation Solution
A hydraulic fluid cooling system that connects fluid lines between the pair of integrated hydrostatic transmissions, using a pump to circulate hydraulic fluid from one transmission to another, eliminating the need for separate coolers and air flow systems, and utilizing a common reservoir to provide cooling capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a hydraulic fluid cooler is provided for each integrated hydrostatic transmission, then the hydraulic fluid temperature can be reduced, but the cost and device complexity increase significantly
Solution Approach 1:
The patent merges the cooling functions of two separate transmissions by connecting their fluid reservoirs through fluid lines. The hydraulic fluid from the downhill transmission (which overheats) is circulated to the uphill transmission (which has available cooling capacity), allowing both transmissions to share a single cooling system instead of requiring two separate coolers.
Solution Approach 2:
The uphill transmission's fluid reservoir serves multiple functions: it acts as both the fluid storage for the uphill transmission and as a heat sink/cooler for the downhill transmission's hydraulic fluid. This multi-functional use eliminates the need for dedicated cooling components.
2Temperature
If a hydraulic fluid cooler is provided for each integrated hydrostatic transmission, then the hydraulic fluid temperature can be reduced, but the system becomes prone to plugging by debris
Solution Approach 1:
The patent extracts the cooling function from dedicated cooler components and relocates it to the existing fluid reservoirs and fluid lines. By using the reservoirs as heat exchange surfaces rather than requiring separate cooler assemblies, the system eliminates components that would be susceptible to plugging by debris in the mowing environment.
3Temperature
If the surface area of transmission housing is increased to dissipate heat, then cooling capacity improves, but cost and space constraints are violated
Solution Approach 1:
The system uses the existing hydraulic fluid in the uphill transmission's reservoir as a self-service cooling medium. The fluid naturally circulates through the connected lines to the downhill transmission, absorbing heat without requiring external cooling systems or modifications to the transmission housing surface area.
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 effectively cools hydraulic fluid without increasing costs or susceptibility to plugging, providing sufficient cooling capacity without additional cooling air, thus addressing temperature issues in hydrostatic transmissions.
Implementation Method 1
The hydraulic fluid cooling system can send hydraulic fluid from the sump or reservoir of each integrated hydrostatic transmission to the other transmission, providing the cooling capacity of a non-loaded transmission to cool hydraulic fluid for a fully loaded transmission.
Data Source
AI summary
A hydraulic fluid cooling system for a pair of integrated hydrostatic transmissions includes a common reservoir holding hydraulic fluid and having hydraulic lines connecting the common reservoir to each integrated hydrostatic transmission, a hydraulic fluid reservoir inside each integrated hydrostatic transmission, and a pump for pumping fluid from each transmission's hydraulic fluid reservoir to the other transmission. Hydraulic fluid lines link each transmission's hydraulic fluid reservoir to the other transmission. The system pumps hydraulic fluid from the sump or reservoir of each integrated hydrostatic transmission to the other transmission, providing the cooling capacity of a non-loaded transmission to cool hydraulic fluid for a fully loaded transmission.