Toothless Wheel Adhesion Transmission for Watch Torque Stability
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Solution Overview
Problem
Traditional mechanical watch movements experience torque inconsistencies due to gear tooth contact, which affects chronometric performance, and existing toothless wheel solutions complicate the mechanism and are difficult to implement in going trains.
Innovation Solution
A mechanical transmission system using two toothless wheels in contact by adhesion, with a hub and elastic arms connecting the hub to a peripheral part to maintain contact pressure, ensuring precise center distance and high friction coefficient for efficient torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional toothed gears are used for mechanical transmission, then the gear train can transmit torque, but the contact between teeth generates disturbances and torque variations that affect chronometric performance
Solution Approach 1:
The invention removes the teeth from the wheels, extracting the harmful contact mechanism while retaining the essential torque transmission function. The toothless wheels transmit torque through adhesion and friction between their peripheries, eliminating the disruptive tooth contact while maintaining the gear train's primary function of transmitting and transforming torque from the mainspring barrel to the escapement.
2Object-generated harmful factors
If toothless wheels are used for adhesion-based transmission, then torque transmission becomes smoother, but the center distance between wheels must be extremely precise to prevent loss of adhesion and slippage
Solution Approach 1:
The invention introduces elasticity to the wheel structure, allowing the wheels to dynamically adapt to center distance variations. The elastic deformation of the wheel peripheries compensates for manufacturing tolerances and assembly variations in center distance, maintaining continuous adhesion contact without requiring extremely precise positioning. This dynamic compliance transforms a rigid precision requirement into a forgiving elastic interaction.
3Reliability
If one wheel is mounted on a rocker arm with a spring to maintain contact pressure, then adhesion contact is maintained, but the mechanism becomes greatly complicated and difficult to apply to a finishing gear
Solution Approach 1:
The invention merges the contact pressure maintenance function directly into the wheel structure itself through elastic arms that are integral to the wheel assembly. Instead of separating the pressure maintenance mechanism (spring on rocker arm) from the transmission element (wheel), the elastic arms are incorporated as part of the wheel, eliminating the need for external rockers and springs while maintaining continuous adhesion contact. This integration dramatically simplifies the mechanism while preserving the essential contact pressure function.
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
This solution stabilizes torque transmission, reducing mechanical disturbances and maintaining chronometric performance by ensuring consistent contact pressure and high efficiency in watch train mechanisms, even in complex going train systems.
Implementation Method 1
a first toothless wheel (1) comprising a hub (3), a peripheral part (5) in contact with the second wheel (2) and elastic arms (4) connecting the hub (3) to the peripheral part (5), the elastic arms (4) being arranged to press the peripheral part against the second wheel (2)
Implementation Method 2
the coefficient of friction of the pair of materials in which the first and second wheels are made is at least 0.5, preferably at least 0.7
Data Source
Figure 1~3
Figure 4~7
AI summary
The mechanical transmission system comprises a first toothless wheel (1) and a second toothless wheel (2) in contact with each other such that one can drive the other by friction. The first wheel (1) includes a hub (3), a peripheral part (5) in contact with the second wheel (2), and elastic arms (4) connecting the hub (3) to the peripheral part (5). The elastic arms (4) are arranged to press the peripheral part (5) against the second wheel (2) and thus prevent loss of traction.