Harmonic Drive Clamping Geometry for Stable Camshaft Friction Torque
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Solution Overview
Problem
Existing variable speed gear arrangements for camshafts in internal combustion engines face challenges in maintaining consistent friction torque and operational reliability, leading to potential slippage and reduced performance.
Innovation Solution
The proposed adjusting gear arrangement incorporates a strain wave gear device with a deformation section that includes a contact surface and a deformation surface, allowing for a clamping connection that maintains a constant friction radius and generates a higher friction torque, reducing slippage and enhancing operational reliability through a cost-effective design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional clamping assembly with a screw is used to connect the ring gear to the camshaft, then the structure is simple and easy to manufacture, but the friction torque is insufficient and slippage occurs during operation
Solution Approach 1:
The patent changes the geometric parameters of the clamping assembly by introducing a deformation section with specific contact surface and deformation surface configurations. This modifies the friction characteristics and contact pressure distribution, thereby increasing friction torque and preventing slippage without fundamentally changing the clamping mechanism structure.
Solution Approach 2:
The deformation section incorporates curved surfaces (contact surface and deformation surface) that improve contact area and pressure distribution between the clamping assembly components. This curvature-based design enhances friction torque generation while maintaining structural simplicity.
2Reliability
If the friction radius varies during operation, then the clamping assembly is simpler to design, but the friction torque becomes inconsistent leading to slippage
Solution Approach 1:
The patent introduces a deformation section with specifically designed contact surface and deformation surface that maintain a constant friction radius during operation. This geometric configuration ensures consistent friction torque while remaining manufacturable through standard machining processes.
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 effectively reduces slippage and increases operational reliability by maintaining a consistent friction radius and generating a higher friction torque, while being cost-effective to produce.
Implementation Method 1
The deformation section (7) has a contact surface (7a) and a deformation surface (7b). The contact surface (7a) bears against the clamping connection partner. The clamping assembly partners are clamped together so that the deformation section (7) is deformed and the deformation surface (7b) lies flat against the clamping connection partner.
Data Source
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AI summary
The invention relates to a variable-speed gear arrangement (1) for a vehicle, comprising a harmonic drive device (2), a driven wheel (4) and a stop disk (5), the stop disk (5) being arranged between the driven wheel (4) and the shaft (3), with a fixing means (8) for connecting the shaft (3) to the stop disk (5) and the driven wheel (4), the fixing means (8) pressing the shaft (3), the stop disk (5) and the driven wheel (4) together in the axial direction such that a clamping connection is formed, the driven wheel (4) and/or the shaft (3) and/or the abutment disk (5) comprising a deformation section (7), the deformation section (7) comprising a contact surface (7a) and a deformation surface (7b). In a first state of assembly, the deformation section (7) brings a member of the clamping connection into contact with the contact surface (7a) and the deformation surface (7b) simultaneously forms a free deformation region (7c) in relation to the member of the clamping connection, and in a second state of assembly, the contact surface (7a) and the deformation surface (7b) are applied to the member of the clamping connection in a flat manner.