Transmission Actuation Cam for Stable Short-Rotation Gear Shifting
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Solution Overview
Problem
Existing actuation devices for transmission systems require a 180° rotation of the actuating rod to switch between actuation end positions, leading to longer actuation times, the need for precise angular positioning, and unstable end positions, which can result in unintended disengagement of speed ratios.
Innovation Solution
An actuation device with an electric motor connected to a speed reduction device, featuring an actuation cam that pivots through three angular sectors, allowing the receiving part to move axially between stable end positions, reducing the angular displacement to less than 180° and incorporating symmetrical and constant bearing widths to improve accuracy and reduce electricity consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a 180° rotation of the actuating rod is used to switch between actuation end positions, then the actuation device can achieve the required movement range, but the actuation time becomes longer
Solution Approach 1:
The patent changes the rotation angle parameter from 180° to less than 180° (specifically around 90°), which directly reduces the actuation time while still achieving the required axial movement of the receiving part between end positions
Solution Approach 2:
The patent introduces a new geometric dimension by using an actuation cam with a specific profile shape that converts rotational movement into axial movement more efficiently, allowing the receiving part to achieve the same axial displacement with a smaller rotation angle
2Reliability
If a 180° rotation of the actuating rod is used, then the actuation range is sufficient, but precise angular positioning is required to maintain stable end positions
Solution Approach 1:
The actuation cam profile is designed to automatically maintain the receiving part in stable equilibrium positions at the end positions, where the cam geometry itself provides the positioning stability without requiring external sensors or precise angular control systems
Solution Approach 2:
The cam profile incorporates transition zones that gradually guide the receiving part into the stable end positions, preventing sudden jumps or instability and ensuring smooth engagement without requiring high precision angular positioning
3Ease of manufacture
If angular variation of a few degrees on the actuating rod occurs, then manufacturing tolerances are easier to achieve, but the movable sliding sleeve may disengage and lose stability
Solution Approach 1:
The patent changes the geometric parameters of the actuation cam, specifically the bearing width and profile shape, to create a mechanism that is less sensitive to angular variations and manufacturing tolerances while maintaining reliable engagement
Solution Approach 2:
Instead of requiring the actuating mechanism to maintain precise angular positioning to ensure stability, the patent inverts the approach by designing the cam profile to inherently provide stability even with angular variations, making the system robust against manufacturing tolerances
Data Source
AI summary
Actuation device for a transmission system includes an electric motor kinematically connected to a speed reducer and an output shaft of the speed reducer of axis of rotation, the output shaft being arranged to pivot through three adjacent angular sectors, a first angular sector, a second angular sector adjacent to the first angular sector, and a third angular sector adjacent to the second angular sector. An actuation cam is rigidly connected to the output shaft for rotation therewith. A receiving part is axially movable along a main axis perpendicular to the axis of rotation, comprising a receiving recess for receiving the actuation cam formed by two surfaces parallel to each other and perpendicular to the main axis.