Multi-Regime CVT for Wheel Loader Shuttling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional transmissions in wheel loaders face challenges in accommodating the vertical drop between the engine output shaft and driven wheels, while also efficiently handling the requirement for frequent clutch engagement and disengagement during 'shuttling' operations at low speeds and high torques.
Innovation Solution
A multi-regime continuously variable ratio transmission (CVT) system incorporating a ratio varying unit with first and second epicyclic gear sets and a clutch system, allowing for selective connection of the output to the transmission output shaft, enabling efficient 'shuttling' and accommodating the vertical drop, with the use of a double shunt to moderate power recirculation at low speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional transmissions are used to accommodate the vertical drop between engine output shaft and driven wheels, then the transmission can be constructed within available space, but frequent clutch engagement and disengagement is required during shuttling operations at low speeds and high torques
Solution Approach 1:
The transmission is divided into multiple regimes or modes of operation, allowing the system to switch between different transmission paths. This segmentation enables optimized operation for shuttling tasks without requiring frequent clutch engagements, as each regime is designed for specific operational requirements
Solution Approach 2:
The transmission system incorporates variable or adjustable characteristics that allow it to adapt dynamically to different operational conditions. This includes the ability to change transmission ratios and engage different power paths based on whether the vehicle is performing shuttling operations or other tasks, reducing the need for frequent clutch operations
2Ease of operation
If a ratio varying unit is used to enable shuttling at low speeds, then clutch engagement requirements are reduced, but power recirculation through the variator increases at low speeds with high torque
Solution Approach 1:
An intermediary mechanism or control system is introduced to manage power flow through the ratio varying unit. This intermediary allows the system to bypass or limit power recirculation paths when operating at low speeds with high torque, while still maintaining the ability to perform shuttling operations through the variator when appropriate
Solution Approach 2:
The transmission system changes operational parameters such as transmission ratio, power path selection, or engagement state of different transmission modes based on operating conditions. At low speeds with high torque, the system adjusts parameters to minimize power recirculation through the variator, while maintaining shuttling capability when needed
3Loss of energy
If a double shunt with epicyclic gear sets is introduced to moderate power recirculation, then power management at low speeds is improved, but transmission construction complexity increases
Solution Approach 1:
Multiple transmission functions are merged into a integrated gear set arrangement. The epicyclic gear sets are combined with the ratio varying unit and control mechanisms to create a unified transmission system that moderates power recirculation while maintaining relatively compact construction, reducing the overall complexity compared to separate independent systems
4Volume of moving object
If the transmission accommodates the vertical drop of approximately 50 cm from engine output shaft to driven wheels, then the transmission can be constructed in the available vertical space, but the arrangement constraints limit design options
Solution Approach 1:
The transmission system utilizes vertical space efficiently by arranging components in multiple dimensions. The epicyclic gear sets and ratio varying unit are configured to accommodate the 50 cm vertical drop while maintaining design flexibility through modular arrangements that can adapt to different spatial constraints and operational requirements
Data Source
AI summary
A multi-regime continuously variable ratio transmission has a transmission input shaft, a transmission output shaft, and a ratio varying unit having a rotating input and a rotating output, the rotational axes of the input and the output being coaxial. A shunt having first and second epicyclic gear sets is connected across the ratio varying unit. One gear set has an input driven by the input shaft and an input driven by one side of the ratio varying unit and the other gear set has an input from the first gear set and an input from one side of the ratio varying unit. The gear sets rotate about a common axis and are offset with respect to, and parallel to, the rotational axes of the input and output of the ratio varying unit. A clutch is operable to selectively connect the output of the second gear set to the output shaft.