Three-Planet Differential Housing With Coolant Windows
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Solution Overview
Problem
Conventional differentials face challenges in balancing bearing capability, cooling effect, and volume miniaturization due to the generation of heat and friction among components, which can lead to performance degradation and damage from excessive temperature if not adequately cooled or lubricated.
Innovation Solution
A differential design incorporating three planetary gears mounted on the housing with a window for coolant inflow and outflow between the planetary gear axes, allowing for active lubrication and cooling, while maintaining structural strength and reducing housing volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of planetary gears is increased to improve bearing capability, then the bearing capability is improved, but the housing volume increases and cooling becomes more difficult
Solution Approach 1:
The patent positions the cooling window between the axes of adjacent planetary gears in the circumferential direction, utilizing the radial dimension of the housing rather than increasing axial or longitudinal dimensions. This allows coolant flow path optimization without increasing overall housing volume, resolving the contradiction between bearing capability (requiring multiple planetary gears) and volume minimization.
Solution Approach 2:
The cooling window is strategically located at specific positions between planetary gear axes where space is available, creating localized cooling zones rather than requiring uniform cooling throughout the entire housing. This allows effective cooling with minimal housing volume and targeted heat dissipation from critical areas.
2Temperature
If a cooling window is added to the housing for coolant flow, then cooling and lubrication are improved, but the housing structure becomes more complex
Solution Approach 1:
The cooling window serves multiple functions simultaneously: it allows coolant inflow and outflow for thermal management, provides lubrication access to planetary gears, and acts as a structural element of the housing itself rather than an added component. This multi-functionality reduces overall system complexity despite adding cooling capability.
Solution Approach 2:
The cooling window is integrated directly into the housing structure as a unified component rather than being a separate attachment. The housing and cooling window form a single structural entity, eliminating the need for additional fastening mechanisms or separate cooling chambers, thereby reducing structural complexity.
3Volume of stationary object
If the housing volume is reduced for miniaturization, then volume miniaturization is achieved, but space for coolant flow and component accommodation is reduced
Solution Approach 1:
The patent utilizes the circumferential direction (radial dimension) of the housing to position cooling windows between planetary gear axes, rather than reducing cooling capacity to achieve volume miniaturization. This dimensional approach allows compact housing volume while maintaining adequate coolant flow paths through strategic positioning in the radial plane.
Solution Approach 2:
The cooling window is pre-positioned between the axes of adjacent planetary gears during the design phase, optimizing the coolant flow path before assembly. This preliminary positioning ensures that coolant can efficiently reach critical heat generation areas without requiring larger housing volume, achieving miniaturization while preserving cooling effectiveness.
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 design enhances bearing capability, ensures effective cooling and lubrication, reduces wear, and extends the service life of the differential by preventing damage from high temperatures, while achieving volume miniaturization.
Implementation Method 1
the coolant may lubricate or cool the three planetary gears and the two side gears inside the housing of the differential through the at least one window
Implementation Method 2
the coolant may lubricate or cool the three planetary gears and the two side gears inside the housing of the differential through the at least one window
Implementation Method 3
components including a plurality of gears, a gear shaft, a pin shaft, and the like are disposed inside the differential. When the differential is working, components that are in contact with each other or are coupled to each other generate heat through friction
Data Source
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AI summary
This application provides a differential, a powertrain, and a vehicle. The differential includes a housing, three planetary gears, two side gears, and at least one window. The housing is configured to be fixedly connected to a main reduction gear, and the housing can rotate around an axial direction of the housing under a drive of the main reduction gear. Each of the three planetary gears is mounted on an inner wall of the housing through a pin shaft, the three planetary gears are disposed spaced from each other along a circumferential direction of the housing, and the circumferential direction of the housing is a direction of rotation of the housing. The two side gears are disposed on two sides of the three planetary gears along the axial direction of the housing and meshed with the three planetary gears. The main reduction gear drives the housing to rotate around the axial direction of the housing, so that the three planetary gears drive the two side gears to drive two drive shafts respectively. The at least one window penetrates through the housing and is located between axes of two adjacent planetary gears for inflow or outflow of coolant. The differential provided in this application has a good bearing capability and is easy to be cooled and lubricated.