Segmented Pulley Actuation for Smooth Ratio Changes Under Load

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

An actuator system comprising a deflector and followers with protrusions that move pulley segments between engaged and disengaged regions, utilizing an electromagnetic actuator and cam surfaces to manage the engagement and disengagement of pulley segments within a segmented pulley transmission, allowing for efficient ratio changes without interrupting load transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If clutchless multi-ratio transmissions are used to change ratio between rotating elements, then the transmission can function under load without clutch interruption, but the system experiences ratcheting, slippage, and tensioning problems that reduce reliability and efficiency

Engineering Contradiction:

Improvecontinuous operation under loadVSAvoidreliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The pulley is divided into multiple independently actuatable segments that can be selectively engaged or disengaged from the endless drive member. This segmentation allows individual segments to be controlled without affecting the entire pulley system, enabling smooth ratio changes while maintaining continuous load transmission and eliminating ratcheting and slippage issues.

Inventive Principle:

Principle #1Segmentation

2Reliability

If segmented pulley transmissions are implemented to reduce mechanical problems, then reliability and efficiency are improved, but the device complexity increases due to multiple actuatable segments and control mechanisms

Engineering Contradiction:

ImprovereliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Multiple pulley segments are combined into unified stacks that move together as a single unit. This merging reduces the number of independent control mechanisms needed, simplifying the overall device complexity while maintaining the reliability benefits of segmented operation. The unified stacks are actuated by fewer cam or roller-cam systems rather than requiring individual actuators for each segment.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The cam or roller-cam systems serve multiple functions: they simultaneously actuate multiple pulley segments, provide mechanical advantage for engagement, and can be controlled by electromagnetic actuators. This multi-functionality reduces the overall component count and simplifies the control architecture while maintaining reliable segmented operation.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of operation

If multiple pulley segments are actuated individually into and out of engagement, then ratio changes can be achieved smoothly, but the actuator system complexity and control difficulty increase

Engineering Contradiction:

Improvesmooth ratio changesVSAvoidactuator system complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

Multiple pulley segments are combined into unified stacks that move together as a single unit. This merging reduces the number of independent control mechanisms needed, simplifying the overall device complexity while maintaining the reliability benefits of segmented operation. The unified stacks are actuated by fewer cam or roller-cam systems rather than requiring individual actuators for each segment.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The cam or roller-cam systems serve multiple functions: they simultaneously actuate multiple pulley segments, provide mechanical advantage for engagement, and can be controlled by electromagnetic actuators. This multi-functionality reduces the overall component count and simplifies the control architecture while maintaining reliable segmented operation.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 actuator system enhances the reliability and efficiency of segmented pulley transmissions by enabling smooth engagement and disengagement of pulley segments, reducing wear and improving performance under load and high-speed conditions.

Implementation Method 1

An electromagnetic actuator is coupled to the deflector to move the deflector between at least the first position and the second position

Methodology Applied

Scientific EffectElectromagnetic actuation: Electromagnet

Data Source

PatentUS12196314B2Actuator system and segmented pulley transmission including the same

Publication Date: 2025.01.14 INMOTIVE INC

AI summary

An actuator system for moving a plurality of pulley segments of a segmented pulley between an engaged region and a disengaged region is provided. The actuator system comprises: a deflector configured to rotate at least between a first position and a second position; and a plurality of followers, each of the followers comprising a protrusion configured to engage the deflector to move the respective one of the pulley segments between the engaged region and the disengaged region, wherein the deflector is configured to move between the first position and the second position to selectively engage the plurality of followers and direct each of the followers between an engaged position and a disengaged position, to move the plurality of pulley segments between the engaged region and the disengaged region. A segmented pulley transmission comprising the actuator system is further provided.