Gearwheel Tooth Cooling by Inward Fluid Feed at High Speed
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Solution Overview
Problem
Electrically operated vehicles face challenges with lubrication and cooling of gearwheels due to higher rotational speeds, which cause cooling fluid to be thrown outward, preventing efficient cooling.
Innovation Solution
A gearwheel arrangement where cooling fluid is directed radially inwardly toward the gear teeth, utilizing centrifugal forces during rotation to ensure efficient cooling, with optional conduits and nozzles for fluid guidance, allowing for efficient cooling even at high rotational speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling fluid is provided from a radially outer position (cooling fluid bath or sump), then cooling is efficient for low-speed operation, but at high rotational speeds the cooling fluid is thrown outward and cooling efficiency deteriorates
Solution Approach 1:
The patent inverts the conventional cooling approach by providing cooling fluid from a radially inner position instead of a radially outer position. The cooling fluid is directed toward the radially inwardly facing surface of the gear tooth section, which causes the fluid to be pressed radially outward by centrifugal forces during rotation, ensuring the cooling fluid reaches the gear teeth even at high rotational speeds.
Solution Approach 2:
The patent changes the spatial parameter of cooling fluid delivery from radial outer to radial inner position. This parameter change fundamentally alters how centrifugal forces affect the cooling fluid distribution, transforming the harmful outward throwing of fluid at high speeds into a beneficial mechanism that presses fluid toward the gear teeth.
2Power
If gear ratios are increased for heavy-duty vehicles, then torque transmission capability is improved, but gearwheel rotational speed increases leading to worsened cooling efficiency
Solution Approach 1:
The patent applies the inversion principle by delivering cooling fluid from the radially inner side of the gear tooth section rather than from the outer side. This allows the system to handle high rotational speeds that result from large gear ratios in heavy-duty vehicles, maintaining cooling efficiency despite the increased speed.
3Temperature
If cooling fluid is provided radially inside the gear teeth, then cooling efficiency at high speeds is improved, but device complexity increases due to additional guiding means
Solution Approach 1:
The patent employs the self-service principle where the rotating gearwheel itself generates the centrifugal forces necessary to distribute the cooling fluid. The gearwheel's rotation automatically presses the cooling fluid toward the radially inwardly facing surface, eliminating the need for complex external pumping or distribution mechanisms.
Solution Approach 2:
The radially inwardly facing surface acts as an intermediary element that receives cooling fluid from the radial inner side and facilitates its distribution to the gear teeth. This surface geometry naturally guides the cooling fluid flow without requiring additional complex components.
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 maintains efficient cooling of gearwheels during high-speed operation by directing cooling fluid inwardly, ensuring effective heat dissipation and lubrication, even in electric vehicles with large gear ratios.
Implementation Method 1
the rotation of the gearwheel results in cooling fluid being pressed toward the radially inwardly facing surface, radially inside of the gear teeth
Data Source
AI summary
A gearwheel arrangement for a transmission of a vehicle, including:a gearwheel configured to be rotatable about an axis of rotation, the gearwheel including a gearwheel body and an annular gear tooth section extending around the gearwheel body, the gear tooth section including a plurality of external gear teeth, wherein at least a part of the gear tooth section extends past a radially outer portion of the gearwheel body in an axial direction of the gearwheel, so that at least one radially inwardly facing surface is provided opposite of the external gear teeth,means for guiding cooling fluid toward the at least one radially inwardly facing surface so as to cool the gear tooth section during rotation of the gearwheel about the axis of rotation.