Vehicle Drive Unit Lubrication Split for Counter and Hypoid Gears
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Solution Overview
Problem
Existing drive devices using a single type of lubricating oil for both counter and hypoid gears fail to fully utilize the performance of each gear, leading to inefficient operation.
Innovation Solution
The drive device employs separate lubricating oils for the counter gear and hypoid gear chambers, isolated by an oil seal, allowing for efficient operation of both gears while using a common lubricating oil for the electric motor and counter gear chamber, and a high-viscosity oil for the hypoid gear to prevent oil film breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the same lubricating oil is used for both counter gear and hypoid gear, then the device complexity is reduced, but the performance of one of the gears cannot be sufficiently utilized
Solution Approach 1:
The patent divides the gear housing into two separate chambers: a counter gear chamber and a hypoid gear chamber. Each chamber is equipped with its own lubricating oil reservoir and sealing system, allowing different types of lubricating oil to be used for each gear type. The counter gear chamber uses a lubricating oil suitable for spiral bevel gears, while the hypoid gear chamber uses a lubricating oil suitable for hypoid gears, thereby optimizing the performance of each gear system independently.
Solution Approach 2:
The patent applies different lubricating oil characteristics to different locations within the drive device. The counter gear chamber is provided with lubricating oil having properties optimized for spiral bevel gear operation, while the hypoid gear chamber is provided with lubricating oil having properties optimized for hypoid gear operation. This local differentiation ensures that each gear type receives the most appropriate lubrication for its specific operational requirements.
2Reliability
If different lubricating oils are used for counter gear and hypoid gear, then the gear operation performance is improved, but the device complexity increases
Solution Approach 1:
The patent divides the gear housing into two separate chambers: a counter gear chamber and a hypoid gear chamber. Each chamber is equipped with its own lubricating oil reservoir and sealing system, allowing different types of lubricating oil to be used for each gear type. The counter gear chamber uses a lubricating oil suitable for spiral bevel gears, while the hypoid gear chamber uses a lubricating oil suitable for hypoid gears, thereby optimizing the performance of each gear system independently.
Solution Approach 2:
The patent employs sealing structures (such as oil seals or partition walls) as intermediaries to separate the two lubricating oil systems. These sealing elements prevent mixing between the different lubricating oils while allowing the drive shaft to pass through from the counter gear chamber to the hypoid gear chamber. This intermediary sealing mechanism enables the use of different lubricants without requiring completely separate drive trains.
3Device complexity
If a common lubricating oil is used for electric motor and counter gear, then the number of lubricating oil types is reduced, but the efficiency of electric motor cooling may be compromised
Solution Approach 1:
The patent employs a multi-functional lubricating oil in the counter gear chamber that simultaneously serves as both gear lubricant and electric motor coolant. The lubricating oil circulating in the counter gear chamber absorbs heat from the electric motor through thermal conduction and convection, while also providing necessary lubrication for the counter gear. This universal lubricating oil performs multiple functions: lubricating the counter gear, cooling the electric motor, and sealing the chamber.
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 configuration enables efficient operation of both counter and hypoid gears, suppresses oil film breakdown on the hypoid gear, and reduces lubricating oil types used, while maintaining efficient operation and cooling of the electric motor and counter gear.
Implementation Method 1
an oil seal that seals a gap between the first shaft and the case
Implementation Method 2
a common first lubricating oil is used for the electric motor chamber and the counter gear chamber
Implementation Method 3
a high-viscosity oil for the hypoid gear to prevent oil film breakdown
Data Source
AI summary
A drive device mounted on a vehicle, the drive device comprising: an electric motor housed in the electric motor chamber; a first shaft arranged parallel to or coaxial with a rotor shaft of the electric motor; a counter gear for transmitting rotation of the rotor shaft to the first shaft; a second shaft for rotating wheels of the vehicle; a hypoid gear for transmitting rotation of the first shaft to the second shaft; an oil seal for sealing a gap between the first shaft and the case; a first lubricating oil housed in the electric motor chamber and the counter gear chamber; and a second lubricating oil housed in the hypoid gear chamber.