Segmented Pulley Actuation for Synchronized Ratio Shifting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Clutchless multi-ratio transmissions face challenges in functioning effectively at high speeds or under significant loads due to issues like ratcheting, slippage, and tensioning, which affect their reliability and efficiency, limiting their commercial viability.
Innovation Solution
A segmented pulley transmission system with an actuator system comprising engaging and disengaging deflectors, barriers, and a motivator assembly that moves pulley segments between engaged and disengaged regions, allowing for synchronized transitions without interference with the endless member, using solenoids and springs for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If clutchless multi-ratio transmissions are operated at high speeds or under significant loads, then transmission performance should be improved, but mechanical problems such as ratcheting, slippage, and tensioning increase, reducing reliability and efficiency
Solution Approach 1:
The pulley is divided into multiple independently movable pulley segments that can be selectively engaged or disengaged from the endless member. This segmentation allows the transmission to maintain reliable operation under high loads by ensuring positive engagement, while enabling high-speed operation by allowing segments to be disengaged to reduce inertial effects and prevent ratcheting.
Solution Approach 2:
The pulley segments are designed to be dynamically reconfigurable, transitioning between engaged and disengaged states based on operational requirements. This dynamic adjustment allows the system to adapt to varying speed and load conditions, maintaining optimal reliability and efficiency across different operating regimes.
2Adaptability or versatility
If pulley segments are moved between engaged and disengaged regions, then transmission ratio changes are enabled, but synchronization timing becomes critical to avoid interference with the endless member
Solution Approach 1:
The actuator system introduces a radial dimension to the pulley segment movement, allowing segments to move radially inward for engagement and radially outward for disengagement. This radial movement dimension provides an additional degree of freedom that simplifies synchronization control, as segments can be moved out of the contact zone radially without interfering with the endless member's tangential motion.
Solution Approach 2:
An actuator system with deflectors serves as an intermediary mechanism between the control system and the pulley segments. The deflectors guide the pulley segments during engagement and disengagement, simplifying the control requirements by providing mechanical guidance that ensures proper synchronization without complex timing control.
3Productivity
If a traditional actuator system is used to move pulley segments, then transmission ratio changes are achieved, but the window for synchronization is limited and mechanical wear increases
Solution Approach 1:
The actuator system is designed to move pulley segments into and out of the contact zone in advance, before the endless member arrives at the engagement position. This preliminary action extends the synchronization window, allowing more time for proper engagement without increasing mechanical wear, as segments are positioned optimally before contact occurs.
Solution Approach 2:
The actuator system replaces traditional mechanical linkages with an electromotive actuation mechanism. This substitution reduces mechanical wear by eliminating sliding contacts and complex mechanical transmissions in the actuation system, while enabling faster and more precise control of pulley segment movement.
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
Enhances the reliability and efficiency of clutchless multi-ratio transmissions by providing a longer window for synchronization and reducing mechanical wear, thereby improving operational performance under load.
Implementation Method 1
an electromotive force generated on the sled by the stator
Implementation Method 2
The follower engages the cam surface of the sled to move in an axial direction between an extended position and a retracted position as the sled moves between the advanced and retreated positions
Data Source
AI summary
A segmented pulley transmission with an actuator system is disclosed. The actuator system comprises: an engaging deflector radially movable between first active and idle positions; a disengaging deflector radially movable between second active and idle positions; and a motivator assembly for moving the engaging and disengaging deflectors between the active and idle positions. In the first active position, the engaging deflector is configured to move a plurality of pulley segments of the segmented pulley transmission from a disengaged region to an engaged region during rotational operation of the segmented pulley transmission. In the second active position, the disengaging deflector is configured to move the plurality of pulley segments from the engaged region to the disengaged region during rotational operation. In the first and second idle positions respectively, the engaging deflector and the disengaging deflector do not move the plurality of pulley segments during rotational operation of the segmented pulley transmission.