Segmented Coaxial Gearing for High-Torque High-Speed Transmission
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Solution Overview
Problem
Conventional transmission technologies, such as planetary gears, eccentric gears, and harmonic drive transmissions, face limitations in achieving high speed ranges, transmitting high torques, and maintaining robustness and efficiency, with issues like low overload capacity, high friction losses, and vibration problems.
Innovation Solution
A transmission design featuring multiple toothed segments between a drive and a fixed part, allowing for adjustable gear ratios and high torque transmission through linear or rotary movement of tooth segments with selective engagement, enabling high speed ranges up to 6000 rpm and flexible gear ratios from i=10 to i=200, while ensuring compactness and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If planetary gears are used for torque transmission, then high torques can be transmitted, but high transmission speeds cannot be achieved and the gear structure has low rigidity and robustness
Solution Approach 1:
The gear system is divided into multiple independent toothed segments (at least two) that can move relative to each other along the circumferential direction. Each segment can be selectively engaged or disengaged from the toothed ring gear, allowing the system to handle high torques when engaged while maintaining flexibility for high-speed operation by disengaging segments that would limit speed performance.
2Force
If eccentric gears are used for torque transmission, then translations can be produced, but large separating forces are required and very large bearings are needed
Solution Approach 1:
Instead of using an eccentric gear mechanism that requires large bearings to handle separating forces, the patent inverts the approach by using a centrally symmetric toothed ring gear with movable toothed segments. The segments are engaged radially inward toward the center of rotation, converting the problematic outward separating forces into beneficial inward radial forces that enhance meshing stability and eliminate the need for oversized bearings.
3Force
If harmonic drive transmissions are used for torque transmission, then high torques can be transmitted, but the flexspline is subject to permanent loads and cannot withstand overloads
Solution Approach 1:
The toothed segments are designed to be movable rather than fixed, allowing dynamic engagement and disengagement. This dynamic capability enables the system to withstand overloads by disengaging segments under excessive load conditions, preventing permanent damage to individual components while maintaining overall system reliability and torque transmission capability under normal operating conditions.
4Volume of moving object
If conventional gear designs are used, then compactness can be achieved, but gear ratios are limited particularly at high speeds on the drive side
Solution Approach 1:
The toothed segments are designed with multi-functionality to achieve both compactness and adaptable gear ratios. Each segment can be selectively engaged at different positions around the toothed ring gear, enabling a wide range of gear ratios (from i=10 to i=200) while maintaining a compact overall structure. The ability to engage multiple segments simultaneously or individually provides versatile gear ratio selection without increasing the fundamental size of the gearbox.
5Force
If eccentric gears are used for transmission, then translations can be achieved, but high friction losses occur and efficiencies are very low
Solution Approach 1:
The toothed segments are engaged radially inward toward the center of rotation, creating a symmetric force distribution that eliminates the eccentricity-induced separating forces. This equipotential engagement approach ensures that forces are distributed evenly across the tooth contacts, minimizing friction losses and maximizing transmission efficiency while still achieving the desired translation through controlled segment engagement and disengagement.
Data Source
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AI summary
In a gearing, in particular coaxial gearing, hollow shaft gearing, hypoid gearing, axial gearing or linear gearing, with a driving element (7), an element (3) and an output element (11), a stepping-up and transmission of a driving torque between driving element (7) and output element (11) are to take place via a plurality of movable tooth segments (5).