Radially Moving Teeth Transmission With Retained Pivot Pads
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Solution Overview
Problem
Existing gear systems, particularly radial-moving-teeth designs, face challenges when configured as speed increasing transmissions in high torque applications, including reduced efficiency in reverse driven directions and difficulties in achieving compact layouts.
Innovation Solution
A transmission design featuring a fixed gear ring, a first drive member with radially arranged apertures for tooth elements, and a second drive member with cam surfaces that engage the tooth elements via pivot pads, where the pivot pads include a retainer formation to constrain movement and prevent sideways shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If radial-moving-teeth gearbox design is used to achieve compact layout and high gear ratio, then the size and mass of the gearbox is reduced, but the efficiency is reduced when operated in reverse driven direction
Solution Approach 1:
The pivot pads are made movable relative to the tooth elements, allowing them to dynamically adjust their position. This enables the transmission to adapt to reverse driven operation, maintaining efficiency while preserving the compact gearbox design. The movable pivot pads convert static radial-moving-teeth architecture into a dynamic system that performs optimally in both forward and reverse directions.
2Volume of moving object
If radial-moving-teeth design is configured as speed increaser, then compact layout is achieved, but torque loading capability is insufficient
Solution Approach 1:
The movable pivot pads enable the system to dynamically respond to high torque loads in reverse driven direction. This dynamic adaptation allows the compact speed increaser configuration to handle high torque applications that would otherwise be unsuitable for this gear type.
Solution Approach 2:
The invention changes the operational parameters of the radial-moving-teeth design by introducing movable pivot pads, transforming it from a low-torque application gear type to one capable of handling high torque loads while maintaining compact dimensions.
3Ease of operation
If pivot pads are allowed to move freely, then engagement with tooth elements is flexible, but sideways shifting occurs reducing reliability
Solution Approach 1:
The constraint mechanism is segmented into multiple constraint elements that work together. These elements provide lateral stability while preserving the necessary flexibility for proper engagement, achieving both reliability and operational ease simultaneously.
Solution Approach 2:
Different parts of the pivot pad assembly have different degrees of freedom. The pivot pads maintain flexibility in the engagement direction while being constrained laterally, creating local quality differences that satisfy both engagement flexibility and stability requirements.
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 solution enhances the efficiency and compactness of the transmission, allowing it to effectively operate as a speed increasing transmission in high torque applications while minimizing sideways movement of pivot pads, thus improving overall performance and reliability.
Implementation Method 1
a second drive member with cam surfaces that engage the tooth elements via pivot pads
Data Source
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AI summary
A transmission of a 'radially moving teeth' type, comprising a fixed gear ring, a first drive member rotationally supported within the fixed gear ring, the first drive member defining a plurality of radially arranged apertures each of which accommodates a tooth element, and a second drive member which is rotationally supported within the first drive member. The tooth element engage with respective pivot pads. One or more of the plurality of pivot pads comprises: a pivot pad body configured to have a pivot portion shaped for engagement with an associated one of the radially-movable tooth elements of the transmission, the pivot portion extending along a pivot axis, wherein the pivot pad body further comprises an integral retainer formation configured to constrain movement of the associated radially-movable tooth element with respect to the pivot portion in the direction of the pivot axis. Advantageously, the retainer formation guards against movement of the pivot pad in a sideways direction with respect to the corresponding tooth element and achieves this in an elegant way by integrating the retainer formation into the pivot pad.