Helical Cycloidal Reducer for Smoother Power Steering Torque
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Solution Overview
Problem
Cycloidal gear reducers used in power steering systems are complex, heavy, and expensive due to their numerous components, resulting in low driving ratios and irregular motion transmission, leading to jerks, shocks, and operating noises that affect driving comfort and safety.
Innovation Solution
The implementation of helical toothing in cycloidal gear reducers, allowing for a more progressive and extensive meshing of teeth, increasing the gear driving ratio and improving force distribution, along with the integration of the teeth into a single piece with the disk or crown, simplifying assembly and reducing the number of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cycloidal reducers with multiple individual teeth (meshing pins) and coupling fingers are used, then the structure can transmit motion, but the device becomes complex, heavy, and expensive to manufacture
Solution Approach 1:
The patent merges multiple individual meshing pins into a single continuous crown gear structure, and combines multiple coupling fingers into one integrated output shaft structure. This merging eliminates the complexity of assembling numerous discrete parts while maintaining the motion transmission function, directly resolving the contradiction between reliability and device complexity.
Solution Approach 2:
The continuous crown gear serves multiple functions simultaneously: it provides the toothed meshing surface, maintains structural integrity, and distributes loads across its entire circumference. Similarly, the integrated output shaft combines the function of multiple coupling fingers with the rotational output function, reducing part count while preserving motion transmission capability.
2Ease of manufacture
If conventional cycloidal reducers with straight toothing are used, then the structure is simple to manufacture, but the driving ratio is low and motion transmission is irregular causing jerks and shocks
Solution Approach 1:
The patent changes the geometric parameter of the toothing from straight (radial) to helical (inclined at angle α to the generator). This parameter change transforms the meshing action from abrupt and discontinuous to progressive and continuous, eliminating jerks and shocks while maintaining manufacturability through standard helical gear manufacturing processes.
Solution Approach 2:
The helical toothing creates a periodic engagement pattern where teeth gradually come into and out of mesh along the helical path. This periodic action distributes the load transition over time and space, smoothing the motion transmission and eliminating the irregularities caused by simultaneous engagement of multiple straight teeth.
3Power
If conventional cycloidal reducers are used, then the structure can provide reduction, but the reduction ratio is relatively low and does not meet increasing requirements for compact high-ratio reducers
Solution Approach 1:
The patent utilizes the curved helical path of tooth engagement instead of straight radial lines. This curvature allows for a more extended meshing area and greater overlap between driving and driven teeth, effectively increasing the mechanical advantage and achieving higher reduction ratios within a compact geometry without increasing device complexity.
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
This solution enhances the smoothness and efficiency of motion transmission, enabling higher reduction ratios while maintaining a compact design, thus improving driving comfort and safety by reducing jerks and noises.
Implementation Method 1
The cycloidal disk and the crown are provided with a helical toothing, that is to say with a toothing which is inclined by a predetermined helix angle with respect to the generator of the disk, respectively of the crown
Data Source
Figure 1~2
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Figure 6~11
AI summary
The invention relates to a cycloidal gear paIr reducer (1) comprising an input shaft (2), mounted in a reducer casing such that it rotates about an axis referred to as "main axis" (ΖΖ'), an eccentric member (22) carried by the input shaft (2) and rotated by the latter, at least one cycloidal disc (23) rotatably mounted on said eccentric member (22) and having a cycloidal toothing (23T), at least one ring gear (25) provided with a receiving toothing (25T) with which the cycloidal toothing (23T) of the cycloidal disc meshes, and an output shaft (3), separate from the input shaft (2), arranged to be rotated by the cycloidal disc (23); the cycloidal toothing (23T) of the disc (23) and the corresponding receiving toothing (25T) of the ring gear (25) being helical.