Wheel Hub Transmission Torque Management
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Solution Overview
Problem
Conventional drivelines face challenges in achieving smooth gear shifting without increasing transmission complexity, which results in high torques on mechanical components.
Innovation Solution
A wheel hub transmission system incorporating a planetary gear arrangement, clutching devices, and a control system that allows for adjustable drive ratios and torque management, enabling smooth shifting and reduced torque on driveline components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of transmission gears is increased to achieve smooth shifting and better torque distribution, then the gear ratio spread approximation of optimal traction curve is improved, but the hardware and controls complexity increases
Solution Approach 1:
The patent applies a continuously variable transmission (CVT) mechanism that dynamically adjusts the drive ratio between the input shaft and wheel hub, replacing fixed gear steps with continuous variability. This allows smooth torque distribution across the optimal traction curve without requiring multiple discrete gears, thereby achieving smooth shifting while maintaining simpler hardware architecture.
Solution Approach 2:
The invention changes the fundamental parameter from discrete gear ratios to continuous drive ratio adjustment. By implementing a planetary gear arrangement with variable torque multiplication capability, the system can continuously vary the torque distribution ratio, enabling smooth shifting performance equivalent to multiple gears but achieved through a single adjustable mechanism rather than multiple fixed gears.
2Force
If a reduction ratio of 3-4 is used between power source and axle half shafts, then torque multiplication is achieved, but high torques are introduced on drive shaft and mechanical parts
Solution Approach 1:
The patent segments the torque multiplication function by placing a wheel hub transmission at each driven wheel, separating the torque management function from the central drivetrain. This allows torque to be multiplied locally at the wheel hub rather than transmitting high torques through the entire drive shaft and prop shaft system, reducing stress on mechanical parts while maintaining necessary torque multiplication for traction.
3Productivity
If a complex transmission system is implemented to achieve responsive driveline, then gear shifting performance is improved, but the overall system complexity increases
Solution Approach 1:
The patent extracts the torque multiplication and ratio adjustment function from the central transmission system and relocates it to the wheel hub transmission. This separation allows the main transmission to remain simpler while the wheel hub transmission provides the necessary torque management and responsiveness locally at each wheel, achieving responsive driveline performance without increasing overall system complexity.
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 system provides a responsive driveline with reduced complexity, improved torque management, and enhanced vehicle performance, including better cornering, stability, and reduced torque losses, without the need for a complex transmission.
Implementation Method 1
The planetary gear arrangement includes a first portion, a second portion, and a third portion. The first portion is drivingly engaged with the input shaft and the second portion is drivingly engaged with the first portion and the third portion.
Implementation Method 2
The planetary gear arrangement is configured to provide a variable torque multiplication between the input shaft and the wheel hub
Implementation Method 3
The clutching device may be selectively drivingly engaged with one of the first portion of the planetary gear arrangement and the input shaft and the second portion of the planetary gear arrangement. Upon one of engagement and disengagement of the clutching device the first portion of the planetary gear arrangement is fixed with respect to the second portion of the planetary gear arrangement.
Data Source
AI summary
A wheel hub transmission for a vehicle driveline is provided. The wheel hub transmission includes an input shaft, a planetary gear arrangement, a casing member, and a clutching device. The input shaft is drivingly engaged with a power source and the planetary gear arrangement. The planetary gear arrangement is drivingly engaged with the input shaft and is in one of driving engagement and selective driving engagement with the casing member. The clutching device may be selectively drivingly engaged with a portion of the planetary gear arrangement, wherein upon engagement of the clutching device the planetary gear arrangement is fixed. The wheel hub transmission facilitates a torque multiplication at the wheel hub transmission, which reduces an amount of torque applied to a portion of the vehicle driveline.