Spoked Gear Web Layout for Reduced Mesh Misalignment

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Solution Overview

Problem

Conventional gears in electric drive systems of new energy vehicles suffer from poor meshing support and significant mesh misalignment, leading to NVH issues such as howling and beat frequency due to the spoke being located at the middle position of the rim tooth width.

Innovation Solution

The gear design features a spoke with first and second web plates distributed on either side of the rim's center line, providing a distributed support that maintains meshing teeth alignment and reduces mesh misalignment, ensuring smoother meshing and reducing transmission error excitation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the spoke is located at the middle position of the rim tooth width, then the structure is simple, but the support effect on meshing teeth is poor and mesh misalignment amount is large

Engineering Contradiction:
Improvespoke structureVSAvoidmesh misalignment
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The spoke is segmented into multiple web plates (first web plates and second web plates) distributed along the width direction of the rim. This segmentation allows the spoke to provide distributed support at multiple positions, improving meshing support effect and reducing misalignment while maintaining structural simplicity through modular web plate elements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The web plates are strategically positioned at different locations along the width direction of the rim, providing localized support where needed. The first web plates are positioned on one side of the center line and the second web plates on the other side, creating non-uniform local support characteristics that optimize meshing alignment at critical positions.

Inventive Principle:
Principle #3Local quality

2Device complexity

If the spoke provides concentrated support at middle position, then the structure is simple, but the meshing smoothness is poor and transmission error excitation is high

Engineering Contradiction:
Improvespoke structureVSAvoidmeshing smoothness
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The spoke structure is divided into multiple web plates distributed along the width direction, transforming a single concentrated support point into multiple distributed support points. This segmentation enables continuous support across the meshing zone, improving meshing smoothness and reducing transmission error excitation while keeping each individual web plate simple in structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support function is extended from a single-point support in the radial direction to a distributed support system along the width direction (axial dimension). By adding web plates at different axial positions, the spoke provides support across the entire width of the rim, ensuring continuous meshing engagement and smooth power transmission.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4628757A1Gear, electric drive assembly and vehicle
Publication Date: 2025.10.08 BYD CO LTD
  • EP4628757A1 patent drawingFigure 1~2
  • EP4628757A1 patent drawingFigure 3~4
  • EP4628757A1 patent drawingFigure 5~6

AI summary

A vehicle, comprising a gear (100) or an electric drive assembly (1). The gear (100) comprises: a rim (110), a central part (120) and spokes. A peripheral wall of the rim (110) is provided with meshing teeth (111) arranged along a circumferential direction thereof, the central part (120) is located on a radial inner side of the rim (110), and the spokes are connected between the rim (110) and the central part (120). The spokes comprise a plurality of first webs and a plurality of second webs spaced apart along the circumferential direction of the rim (110). Along a width direction of the gear (100), the first webs and the second webs are located on two sides of a central line of the rim (110) respectively.