Rolling-Element Power Transmission for Passive Output Shaft Locking
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Solution Overview
Problem
Existing power transmission devices suffer from significant torque loss and require continuous motor control to maintain the position of the output shaft due to external forces, leading to inefficiency and increased power consumption.
Innovation Solution
A power transmission device with a fixing member, output shaft, input shaft, and rolling elements, featuring a recessed surface design that allows for torque transmission with reduced loss and rotational restriction, eliminating the need for additional components like flange plates and unlocking plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous motor control is used to maintain the position of the output shaft, then the position retention is achieved, but the power consumption increases
Solution Approach 1:
The power transmission device uses a gravity-based locking mechanism where the output shaft's own weight automatically engages the locking surface when the shaft is in the horizontal position, eliminating the need for continuous motor control. The system serves itself by utilizing the external force (gravity) to maintain position rather than requiring active energy input.
Solution Approach 2:
The device transitions from continuous motor control to periodic action by using the motor only when position adjustment is needed. Once positioned, the gravity-based locking mechanism maintains the position passively, with the motor intervening only periodically when repositioning is required.
2Device complexity
If conventional torque transmission structure is used, then the structure is simple, but the torque loss is large
Solution Approach 1:
The power transmission device applies local quality by creating a specific locking surface geometry on the output shaft that engages with a corresponding surface on the support. This localized geometric feature enables efficient torque transmission through direct surface contact rather than through conventional bearing interfaces, reducing torque loss at the critical transmission point.
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 device achieves reduced torque loss, reliable rotational restriction, and reduced power consumption by utilizing a recessed surface design with rolling elements, allowing for efficient torque transmission and position retention without continuous motor control.
Implementation Method 1
a pair of rolling elements disposed between the cylindrical surface and the facing surface and on either side of the pressing portion in a circumferential direction
Implementation Method 2
an input shaft having at least one or more pressing portion, the pressing portion disposed between the cylindrical surface and the facing surface
Data Source
AI summary
A power transmission device includes: a fixing member having a cylindrical surface; an output shaft having a facing surface facing the cylindrical surface; an input shaft having a pressing portion disposed between the cylindrical surface and the facing surface; and a pair of rolling elements. The facing surface includes a recessed surface. The recessed surface has a bottom surface and a pair of pressed surfaces. The bottom surface has a central surface and a pair of cam surfaces. A distance between the cam surface and the cylindrical surface increases from the central surface toward the pressed surface. A distance between the cam surface and the cylindrical surface is smaller than a diameter of the rolling element in the portion closer to the central surface, and is greater than the diameter of the rolling element in the portion closer to the pressed surface.