Variable-Speed Gear Clamping for Constant Friction Radius
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Solution Overview
Problem
Existing variable-speed gear arrangements for vehicles, particularly those using strain wave gears, face challenges in maintaining consistent friction radius and high friction torque, leading to reduced operating reliability and increased production costs.
Innovation Solution
The proposed variable-speed gear arrangement incorporates a deformation section with a contact surface and deformation surface that defines a friction radius and center of pressure, allowing for a clamped assembly with a constant friction radius and adjustable friction torque, reducing slipping and enhancing reliability, while being cost-effective to produce.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a screw connection is used to clamp the ring gear to the camshaft, then the components are connected for conjoint rotation, but the friction radius is not constant and friction torque is insufficient
Solution Approach 1:
The patent introduces a deformation section with variable geometry that changes the contact surface area and friction characteristics. By controlling the deformation parameter (degree of deformation), the friction torque can be adjusted and maintained at optimal levels while ensuring constant friction radius through the specific geometric design of the deformation section
Solution Approach 2:
The deformation section is designed to be elastically deformable, allowing the friction surface to adapt dynamically to operational conditions. This dynamic deformation ensures constant friction radius while maintaining sufficient friction torque through controlled elastic displacement of the deformation section
2Ease of manufacture
If conventional clamping methods are used, then components are connected, but production costs increase and friction control is imprecise
Solution Approach 1:
The deformation section allows precise control of friction parameters through geometric design rather than requiring expensive tight tolerances on all components. The friction characteristics are controlled by the deformation geometry parameters, enabling cost-effective manufacturing with precise friction control
Solution Approach 2:
Instead of requiring high precision throughout the entire assembly, the patent applies precision only where needed - in the deformation section's contact surface geometry. This localized precision approach reduces overall manufacturing costs while achieving the required friction control precision
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 configuration maintains a constant friction radius and increases friction torque, reducing component slipping and improving operating reliability while allowing for low-cost production and precise friction control.
Implementation Method 1
a deformation section (7) with a contact surface (7a) and a deformation surface (7b) which defines a friction radius and a center of pressure
Implementation Method 2
The clamped assembly is designed in such a way that the driven wheel (4) and, optionally, the stop disk (5) are connected frictionally to the shaft (3)
Data Source
AI summary
A variable-speed gear arrangement for a vehicle includes a harmonic drive device, a driven wheel and an optional stop disk. The stop disk can be arranged between the driven wheel and a shaft, with a fastener for connecting the shaft to the stop disk and the driven wheel. The fastener presses the shaft, the stop disk and the driven wheel together in an axial direction. The driven wheel and/or the shaft and/or the stop disk includes a deformation section, and the deformation section includes a contact surface and a deformation surface. In a first state of assembly, the deformation section brings a member of the clamping connection into contact with the contact surface, simultaneously forming a free deformation region. In a second state of assembly, the contact surface and the deformation surface are applied to the member of the clamping connection in a flat manner.