Progressive Steering Gear with Logarithmic Spiral Teeth
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Solution Overview
Problem
Existing progressive gear assemblies for vehicle steering systems are complex, expensive, and prone to backlash and torque fluctuations, with a limited range of motion and early reversal point.
Innovation Solution
A compact progressive gear assembly featuring spur gears with teeth arranged along a curve of increasing radius of curvature, paired with staggered parallel gear racks, eliminating the need for additional components and achieving zero backlash, allowing for 1½ revolutions from end point to end point without torque fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If prior art progressive gear assemblies are used, then progressive steering response is achieved, but device complexity increases and manufacturing cost rises
Solution Approach 1:
The spur gear is designed with a logarithmic spiral tooth arrangement where the radius of curvature increases monotonically over more than 90 degrees of rotation. This curved geometric progression inherently provides the progressive steering response, eliminating the need for complex multi-component mechanisms while achieving the desired operational characteristic.
Solution Approach 2:
The invention changes the geometric parameter of the gear tooth arrangement from conventional circular or linear patterns to a logarithmic spiral configuration. This parameter change in the radius of curvature progression directly enables progressive steering response while maintaining a simple single-gear structure, resolving the contradiction between operational performance and device complexity.
2Ease of operation
If conventional gear assemblies with multiple components are used, then progressive steering is achieved, but backlash and torque fluctuations occur
Solution Approach 1:
The invention merges the functions of multiple gear components into a single integrated spur gear with logarithmic spiral teeth. This consolidation eliminates the interfaces between multiple components that cause backlash and torque fluctuations, while the continuous spiral geometry maintains smooth progressive steering response and uniform torque transmission throughout the rotation.
3Device complexity
If standard spur gears are used, then simple structure is maintained, but range of motion is limited and reversal point is early
Solution Approach 1:
The logarithmic spiral tooth arrangement with monotonically increasing radius of curvature allows the gear to effectively utilize more than 90 degrees of rotational range, enabling 1½ revolutions from end point to end point. This extended angular range is achieved through the continuous curved geometry that maintains proper tooth engagement throughout the extended rotation, overcoming the limited motion range of standard gears while preserving structural simplicity.
Data Source
AI summary
A progressive gear assembly that is a vehicle steering gear, the assembly comprising at least one spur gear (1, 2) and a toothed structure (3, 4, 5, 7, 8) with which the spur gear (1, 2) meshes. The spur gear (1, 2) has teeth (11) arranged along a curve (10), the curve (10) comprising a radius of curvature (r) which monotonically rises over an angular range of more than 90° of the curve (10). Preferably the curve is a spiral, particularly a logarithmic spiral. This gear assembly is configured compact and simple, features smooth running and achieves a late end point.