Split-Pulley Shifting Mechanism Using Differential Ratio Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing transmission systems lack the ability to rapidly and controllably adjust their transmission ratio across a wide range of values, limiting their efficiency and adaptability to changing torque and rotation speed requirements.
Innovation Solution
A transmission system incorporating a conical split pulley with differential mechanisms, where the axial separation of the pulley halves is controlled by input members and a differential, allowing for rapid and precise adjustment of the effective diameter and thus the transmission ratio, enabling continuous variable transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional transmission system with discrete gears is used, then the structure is simple and reliable, but the transmission ratio cannot be continuously adjusted and requires multiple actuators for shifting
Solution Approach 1:
The pulley is divided into two separable half-pulleys that can move independently along the rotation axis. This segmentation allows the belt contact radius to be continuously adjusted by changing the axial distance between the half-pulleys, enabling continuous transmission ratio variation without complex multi-actuator systems
Solution Approach 2:
The differential mechanism serves multiple functions simultaneously: it transmits torque from the input shaft to the output shaft while also controlling the axial separation of the half-pulleys to adjust the transmission ratio. This multi-functionality reduces the need for separate actuators and simplifies the overall system structure
2Ease of operation
If multiple actuators are used to control transmission ratio shifting, then the transmission ratio can be adjusted, but the device complexity and number of moving parts increases
Solution Approach 1:
The differential mechanism is designed to perform dual functions: torque transmission and transmission ratio control. By utilizing the inherent torque difference between input and output, the system automatically controls the axial separation of half-pulleys without requiring additional actuators, thereby simplifying the system while maintaining ease of operation
Solution Approach 2:
The system uses its own operating parameters (torque difference between input and output) to automatically control the transmission ratio adjustment. The differential mechanism self-regulates the axial distance between half-pulleys based on the torque conditions, eliminating the need for external control actuators
3Adaptability or versatility
If the axial separation of split pulleys is increased to change effective diameter, then the transmission ratio can be adjusted, but the response time and shifting speed is limited
Solution Approach 1:
The system enables dynamic adjustment of the transmission ratio during operation by allowing the half-pulleys to move freely along the rotation axis under differential torque control. This dynamic mechanism allows rapid response to changing torque conditions and achieves fast transmission ratio shifting without mechanical constraints
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 solution allows for rapid, controllable shifting of the transmission ratio, reducing the need for multiple actuators and enabling efficient operation across a wide range of output speeds and torques, enhancing the system's adaptability and efficiency.
Implementation Method 1
A differential is coupled to the first and second input members and the first and second half-pulleys such that a torque difference between the first input member and the second input member causes an axial force to be applied, via the differential, between the first half-pulley and the second half-pulley
Data Source
AI summary
A variety of shifter mechanisms are provided for controlling the axial distance between half-pulleys of a split pulley variable transmission, thus controlling the transmission ratio of the variable transmission. Some of these embodiments include a differential such that a variable transmission can be driven and shifted differentially by two inputs. A torque or rotation difference between the inputs results in a change in the transmission ratio and in-common torque or rotation is transmitted through the transmission to an output. The same motors used to drive the output of the transmission are thus also able to effect shifts in the transmission ratio. Accordingly, motor mass that is not being used to effect high-speed shifts may be used to drive the transmission output, and vice versa. The provided shifter embodiments are well-suited to application to nested-pulley variable transmissions, including nested-pulley infinitely variable transmissions.