Two-Speed Drive Module for All-Wheel Drive Packaging
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Solution Overview
Problem
Existing all-wheel drive vehicle systems are complex and costly, with wheel hub motors being impractical for smaller wheels due to size constraints, and current drive modules do not fully address the need for an improved drive module that balances complexity, cost, and packaging considerations.
Innovation Solution
A drive module comprising an electric motor, a differential assembly, a multi-speed transmission assembly with a two-speed planetary transmission stage, and a pair of axle shafts, featuring a first clutch for locking the transmission stage at a 1:1 gear ratio and a second clutch for controlling rotation, allowing for selective operation of the planetary transmission stage to achieve efficient power transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If wheel hub motors are used to provide all-wheel drive, then drive torque can be distributed to wheels, but the motor size becomes relatively large (18 inches or greater) which is impractical for smaller wheels and creates packaging issues
Solution Approach 1:
The drive system is segmented into a central power source (single motor or engine) and distributed wheel drive through a multi-speed transmission assembly with planetary gear sets at each wheel. This allows one motor to provide all-wheel drive capability without requiring large hub motors at each wheel, resolving the contradiction between all-wheel drive capability and motor size.
Solution Approach 2:
A multi-speed transmission assembly with planetary gear sets acts as an intermediary between the central power source and the wheels. This intermediary mechanism distributes drive torque to all wheels while keeping the primary motor compact, enabling all-wheel drive without the need for large hub motors.
2Adaptability or versatility
If conventional all-wheel drive systems with transfer cases and differentials are used, then drive torque can be distributed to front and rear wheels, but the system complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the functions of the transfer case, differential, and multi-speed transmission into a single integrated multi-speed transmission assembly. This merging of components provides all-wheel drive capability while reducing the number of separate parts and simplifying the overall system architecture compared to conventional systems.
Solution Approach 2:
The multi-speed transmission assembly performs multiple functions simultaneously: it acts as a transfer case to distribute torque to front and rear axles, functions as a differential to allow wheel speed variation, and provides multi-speed gear reduction. This multi-functionality reduces system complexity while maintaining all-wheel drive capability.
3Adaptability or versatility
If conventional all-wheel drive systems are installed in two-wheel drive vehicles, then all-wheel drive capability is achieved, but vehicle architecture becomes more complex requiring fuel tank modification and spare tire relocation
Solution Approach 1:
The drive system uses compact planetary gear sets and multi-speed transmission assemblies that can be positioned in available vehicle spaces without requiring major architectural changes. The segmented, modular design allows integration into existing two-wheel drive vehicle layouts while providing all-wheel drive capability.
Solution Approach 2:
The patent utilizes vertical space and available gaps in the vehicle architecture (such as space above the rear axle or in the vehicle center) to locate the multi-speed transmission assemblies, rather than requiring horizontal repositioning of major components like fuel tanks or spare tires. This dimensional approach allows all-wheel drive integration without altering vehicle architecture.
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 solution provides a more efficient and cost-effective drive module that can be used in various wheel configurations, offering improved packaging flexibility and reduced complexity, making it suitable for both hybrid and electric vehicles.
Implementation Method 1
The planet gears are meshed with the sun gear and with the ring gear. The transmission output member is meshingly engaged to the differential input member.
Implementation Method 2
The first clutch is selectively operable for locking the two-speed planetary transmission stage such that it operates in a 1:1 gear ratio.
Data Source
AI summary
A drive module with a hydraulic circuit that includes a reversible motor, a reversible pump driven by the reversible motor, a hydraulic reservoir, a first conduit coupling a first inlet/outlet of the reversible pump to the hydraulic reservoir, a second conduit coupling a second inlet/outlet of the reversible pump to the hydraulic reservoir, first and second hydraulic cylinders, and first and second one-way valves. The first hydraulic cylinder has a third inlet/outlet that is coupled to the first conduit between the reversible pump and the hydraulic reservoir. The second hydraulic cylinder has a fourth inlet/outlet that is coupled to the second conduit between the reversible pump and the hydraulic reservoir. The first one-way valve is disposed in the first hydraulic conduit between the first hydraulic cylinder and the reservoir. The second one-way valve is disposed in the second hydraulic conduit between the second hydraulic cylinder and the reservoir.