Compact Backlash Mechanism with Elastic Arms
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Solution Overview
Problem
Existing backlash gears in horological mechanisms are bulky, require high torque, and induce high friction and energy losses, making them inefficient and difficult to integrate into compact mechanisms.
Innovation Solution
A one-piece, compact watch mobile with backlash is designed, featuring a first toothed rim connected to a hub via rigid arms and a second toothed rim connected to a hub via elastically deformable arms, allowing for minimal angular offset and low torque consumption, achieved through precise machining and assembly techniques such as welding or fusion bonding, ensuring no play between teeth and minimizing energy losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional backlash gear with a long shaft and tube is used, then the wheels can shift angularly to eliminate backlash, but the size of the mechanism increases and high torque is required
Solution Approach 1:
The mechanism is divided into two separate elements (first element with first toothed rim, second element with second toothed rim) that can be assembled together. This segmentation allows each element to be compact while collectively achieving the backlash elimination function through their relative angular displacement capability.
Solution Approach 2:
The patent introduces elastic arms that allow dynamic angular displacement between the two toothed rims. The elastic arms enable the mechanism to adapt its angular position to eliminate backlash while maintaining a compact structure, replacing the static long shaft and tube design.
2Reliability
If a traditional backlash gear with long shaft and tube is used, then backlash can be eliminated, but very high torque is necessary to shift the wheels
Solution Approach 1:
The elastic arms provide a dynamic, compliant connection between the hubs and toothed rims, allowing torque to be applied efficiently to achieve the necessary angular displacement for backlash elimination without requiring excessively high torque values.
Solution Approach 2:
The patent optimizes the angular offset between teeth and the elastic properties of the arms to reduce the torque required for angular displacement, achieving backlash elimination with lower torque compared to traditional rigid shaft designs.
3Reliability
If high torque is used to shift wheels in traditional backlash gear, then backlash is eliminated, but high friction forces are induced leading to energy losses
Solution Approach 1:
By optimizing the angular offset parameter and the elastic characteristics of the arms, the mechanism achieves backlash elimination with minimized torque requirements, thereby reducing friction forces and energy losses during operation.
Solution Approach 2:
The dynamic elastic connection allows for smooth angular displacement with reduced friction compared to rigid connections, minimizing energy losses while maintaining the backlash elimination function.
4Reliability
If toothed wheels are made thick to accommodate a spring, then backlash can be eliminated, but the mechanism becomes bulky and assembly is complicated
Solution Approach 1:
The mechanism is segmented into two separate thin elements that are assembled together, eliminating the need for thick wheels to accommodate springs. The backlash elimination function is achieved through the relative positioning and elastic connection of these thin elements rather than through wheel thickness.
Solution Approach 2:
The elastic arms provide the necessary compliance and angular displacement capability in a thin-profile design, replacing the need for thick wheels with internal springs, thereby achieving compactness while maintaining backlash elimination functionality.
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 results in a lightweight, compact, and efficient backlash mechanism with reduced energy consumption, maintaining high precision and preventing backlash issues while allowing for easy integration into kinematic chains, with energy losses minimized to less than 10% of the torque transmitted.
Implementation Method 1
a second element (2) comprising a second toothed rim (2.1), a second hub (2.2) and second elastically deformable arms (2.3) connecting the second hub (2.2) to the second rim (2.1)
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
The invention relates to a clockwork train with clearance compensation, consisting of a one-piece assembly including a hub (1.2, 2.2), a first toothed rim (1.1) which is rigidly connected to the hub (1.2, 2.2) and a second toothed rim (2.1) which is connected to the hub (1.2, 2.2) by at least one second resiliently deformable arm (2.3) allowing an angular movement of the second rim (2.1) with respect to the first rim (1.1).