Helical Gear Transmission with Split Thrust Collars for Low Sliding Loss
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Solution Overview
Problem
Current gear drives with helical gears face challenges in size, cost, and efficiency due to additional axial forces, with existing solutions either compromising on efficiency or increasing construction complexity, and often resulting in acoustic disadvantages.
Innovation Solution
The solution involves spatially separating contact surfaces for tensile and shear torques, with the first contact surface positioned close to the pitch circle diameter for efficient traction and the second below the root circle diameter for overrun mode, using radially offset contact points and differing geometry for each, potentially eliminating the need for separate pressure collars and minimizing acoustic issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If pressure collar contact point is located away from the rolling point (directly below root circle diameter), then construction is compact and cost-effective, but sliding speed at contact point is high causing efficiency losses
Solution Approach 1:
The patent divides the single contact point into two separate contact points: one for tensile torques (M+) and one for shear torques (M-). This segmentation allows each contact point to be optimized independently for its specific torque direction, resolving the contradiction between construction simplicity and efficiency by eliminating the need for high sliding speeds at a single contact point.
Solution Approach 2:
The patent applies different contact point locations and pressure ridge geometries for different torque directions. The first contact point for tensile torques is positioned to minimize sliding speed, while the second contact point for shear torques is positioned differently. This local differentiation optimizes efficiency for the primary driving direction while maintaining compact construction.
2Loss of energy
If pressure ridge contact point is close to the rolling point, then sliding speed is low improving efficiency, but additional components such as pressure collars and axial pressure elements are required
Solution Approach 1:
The patent segments the pressure transmission function into two separate contact points with dedicated pressure ridges, eliminating the need for additional pressure collar components. The first pressure ridge handles tensile torques and the second pressure ridge handles shear torques, achieving component reduction while maintaining efficiency.
Solution Approach 2:
The pressure ridges are designed to perform multiple functions: they simultaneously serve as load transmission elements and as components that define the contact point geometry. This multi-functionality eliminates the need for separate pressure collars and axial pressure elements, resolving the contradiction between efficiency and construction complexity.
3Device complexity
If pressure collar runs against lateral gear wheel surfaces, then construction is simplified, but interrupted track stimulates vibrations causing acoustic disadvantages
Solution Approach 1:
The patent applies different contact point locations and pressure ridge geometries for different torque directions. The first contact point for tensile torques is positioned to minimize sliding speed, while the second contact point for shear torques is positioned differently. This local differentiation optimizes efficiency for the primary driving direction while maintaining compact construction.
4Device complexity
If single contact point is used for both tensile and shear torques, then construction is simple, but efficiency is compromised for one of the torque directions
Solution Approach 1:
The patent divides the single contact point into two separate contact points: one for tensile torques (M+) and one for shear torques (M-). This segmentation allows each contact point to be optimized independently for its specific torque direction, resolving the contradiction between construction simplicity and efficiency by eliminating the need for high sliding speeds at a single contact point.
Data Source
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AI summary
The invention relates to a gearwheel transmission having a first and a second helically toothed gearwheel (1, 2) which mesh with one another in order to transmit torques in different directions, for example for traction and overrun torques, and the toothings (3) of the first and second gearwheels (1, 2) each have a root circle diameter (12) and a rolling circle diameter (13), and the first and second gearwheels (1, 2) each have corresponding ring-shaped thrust collars (4, 5), and corresponding thrust collars (4, 5) form in each case one raceway (8, 9, 10, 11) with an overlap region, such that a first and a second raceway (8, 9) for traction torques and a third and a fourth raceway (10, 11) for overrun torques are formed, and each overlap region has a contact surface or a contact point (14, 15), and each contact point (14, 15) lies on a contact circle diameter (16, 17), wherein the contact surfaces or contact points (8, 9) for traction torques and the contact surfaces or contact points (10, 11) for overrun torques are arranged spatially separately from one another, such that first and second contact surfaces or contact points (14, 15) are formed and the first and second contact surfaces or contact points (14, 15) for traction and overrun torques are arranged radially offset with respect to one another.