CVT Transmission Element with Movable Engaging Elements
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Solution Overview
Problem
Existing pulleys for continuously variable transmissions have limited variability in the running radius, restricting their range of application due to the form-locked engagement with toothed belts.
Innovation Solution
A transmission element comprising an elongate flexible endless carrier element with movable engaging elements that can move between active and passive positions, allowing engagement with pulleys having radial contact elements, ensuring form-locked transmission while preventing conflicting contacts by moving out-of-phase elements to a passive position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact blocks are made reciprocally movable radially to define running radius with toothed belt engagement, then form-locked transmission is achieved, but the running radius can only be varied to a limited extent
Solution Approach 1:
The engaging elements are made dynamically movable between active and passive positions through spring action. When a engaging element encounters a tooth of a contact element, spring force moves it to the passive position, allowing the running radius to adjust dynamically. This enables continuous variable transmission ratio variation while maintaining form-locked engagement when needed.
Solution Approach 2:
The invention changes the state parameter of the engaging elements from fixed to variable. By allowing engaging elements to switch between active (protruding) and passive (retracted) positions, the effective running radius becomes a variable parameter rather than a fixed one, enabling continuous adjustment of transmission ratio.
2Ease of operation
If engaging elements are provided at fixed pitch in the carrier element, then co-action with pulley contact elements is enabled, but conflicting contacts occur when elements are out of phase
Solution Approach 1:
The engaging elements are designed to move dynamically between active and passive positions. When an engaging element is out of phase with contact element teeth and would cause conflicting contact, spring force automatically moves it to the passive position, eliminating the harmful conflict while maintaining operational capability when in phase.
Solution Approach 2:
The invention converts the potential harmful conflicting contact into a useful mechanism for adjusting the running radius. When an engaging element encounters a tooth that would cause conflict, the spring force moves it to the passive position, and this same mechanism enables continuous variation of the transmission ratio.
3Reliability
If engaging elements protrude further inward in active position, then form-locked engagement with pulley is achieved, but conflicting contact occurs when out of phase with contact elements
Solution Approach 1:
The engaging elements are designed with spring action that allows them to move between active (protruding for engagement) and passive (retracted to avoid conflict) positions. This dynamic behavior ensures form-locked engagement when needed while avoiding conflicting contact when out of phase.
Solution Approach 2:
The spring force acts in advance to move engaging elements to the passive position before conflicting contact can occur. When an engaging element approaches a tooth that would cause conflict, the spring force preemptively retracts it, preventing the harmful contact.
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
Enables a wide range of transmission ratio variation in continuously variable transmissions, ensuring reliable and efficient force transmission by maintaining a uniform pitch between engaging elements, thus enhancing the flexibility and durability of the transmission system.
Implementation Method 1
an endless spring element extending through the passage in the carrier element and through the passage of each of the number of engaging elements, wherein the spring element is configured to provide, for each of the number of engaging elements, resistance from spring action of the spring element during movement of the respective engaging element from the active position in the direction of the passive position
Data Source
AI summary
A transmission element for a transmission such as a continuously variable transmission, including an elongate flexible endless carrier element provided with a number of receiving spaces with an opening and with a passage extending through the number of receiving spaces in the longitudinal direction of the carrier element, a number of engaging elements which are each received in a receiving space for movement between an active position and a passive position and which in the active position protrude further inward than in the passive position and at least out of the opening of this receiving space so as to be able to engage in the active position with a pulley of the transmission, and a spring element for providing resistance for each of the number of engaging elements during movement from the active position in the direction of the passive position.