Friction Rotation Coupling for Low-Play Shaft Alignment
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Solution Overview
Problem
Existing robots that use bevel gears for rotation transmission from a motor's shaft to a driven shaft face issues with play and accuracy due to dimensional tolerance, particularly in small motor and gear systems.
Innovation Solution
A rotation transmitting device with a first and second rotating shaft, utilizing a transmitting member and an intermediate transmitting member to transmit rotation through friction, allowing for precise alignment and reduced play.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bevel gears are used for rotation transmission, then rotation can be transmitted from motor shaft to driven shaft, but play occurs in movement and alignment accuracy deteriorates due to dimensional tolerance
Solution Approach 1:
A friction transmission mechanism is introduced as an intermediary between the motor shaft and driven shaft, replacing direct gear meshing. The friction transmission member contacts both shafts through friction rather than mechanical engagement, eliminating the need for precise alignment while reliably transmitting rotation and torque.
Solution Approach 2:
The patent replaces the traditional mechanical gear engagement system with a friction-based transmission system. Instead of relying on toothed gears that require precise alignment, the system uses friction between contact surfaces to transmit rotation, thereby eliminating play and improving alignment tolerance.
2Force
If bevel gears are used for rotation transmission, then torque can be transmitted, but dimensional tolerance causes misalignment and reduces transmission precision
Solution Approach 1:
The friction transmission member acts as a mediator that transfers torque from the motor shaft to the driven shaft through friction contact. This intermediary mechanism accommodates dimensional variations and misalignment while maintaining effective torque transmission without the precision requirements of direct gear engagement.
Solution Approach 2:
The patent changes the transmission mechanism from rigid mechanical engagement to friction-based contact, altering the fundamental parameter of how torque is transmitted. This allows the system to tolerate dimensional variations and maintain transmission precision despite manufacturing tolerances in the shafts and gears.
3Volume of moving object
If small motors and gears are used in built-in actuators, then device size is reduced, but alignment accuracy and play reduction become more difficult
Solution Approach 1:
In small built-in actuators, the friction transmission member serves as a critical intermediary that compensates for the limited space and reduced manufacturing precision. The friction-based contact mechanism allows torque transmission without requiring the high alignment accuracy that would be difficult to achieve in compact actuator designs.
Solution Approach 2:
The actuator is segmented into distinct components (motor shaft, friction transmission member, driven shaft) that can be manufactured separately with standard tolerances and assembled without requiring ultra-precise alignment. The friction transmission member acts as a buffer that accommodates dimensional variations in these segmented components.
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 effectively reduces play in rotation transmission and facilitates accurate alignment of the rotating parts, enhancing the precision and efficiency of robotic movements.
Implementation Method 1
friction arising between an external surface of the first rotating part and an internal surface of the transmitting member; friction arising between an external surface of the second rotating part and the internal surface of the transmitting member
Implementation Method 2
friction arising between the external surface of the first rotating part and an external surface of the intermediate transmitting member, and friction arising between the external surface of the second rotating part and the external surface of the intermediate transmitting member
Data Source
Figure 1A~1B
Figure 1C
Figure 2
AI summary
Disclosed herein is a rotation transmitting device which permits the transmission of rotation with a reduced play and which permits the constituents to be aligned easily. The rotation transmitting device has a transmitting member (30) which surrounds a rotating part (12) of a drive shaft (11) and a rotating part (22) of a driven shaft (21). At least either the rotating part (12) of the drive shaft (11) or the rotating part (22) of the driven shaft (21) has an external surface that comes into contact with the internal surface of the transmitting member (30) so that friction arising between the internal surface and the external surface achieves torque transmission and reception to and from the transmitting member (30).