Disc Brake Planetary Gear Layout for Stable Gear Meshing
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Solution Overview
Problem
The existing disc brake design with a planetary gear speed reduction mechanism experiences issues with gear meshing conditions due to offset load positions and reaction forces, leading to potential inclination and adverse effects on performance, strength, and operation noises.
Innovation Solution
The design incorporates a sun gear, planetary gears, and an internal gear with a supporting and reaction force receiving configuration, where the internal gear's flat surface and reaction force receiving portion are positioned to align with the sun gear, preventing moment generation and improving meshing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the load position and reaction force position are offset in the axial direction, then the structure is simpler, but a moment is generated that causes inclination of the sun gear and internal gear, deteriorating meshing conditions
Solution Approach 1:
The invention transitions from a two-dimensional planar support to a three-dimensional spatial arrangement by adding the reaction force receiving portion that extends in the axial direction. This allows the reaction force to be received at a position that overlaps with the load application point when viewed from the radial direction, creating a moment-free configuration while maintaining structural simplicity.
2Volume of moving object
If there is a small space between the sun gear and cover member, then the device is more compact, but the sun gear and internal gear may incline, aggravating meshing condition
Solution Approach 1:
The invention applies preliminary anti-action by pre-positioning the reaction force receiving portion to counteract the moment that would cause inclination. By receiving the reaction force at a position that overlaps with the load application point, the design prevents inclination before it occurs, ensuring stable meshing conditions even in the compact space between the sun gear and cover member.
3Ease of manufacture
If gear tooth surfaces unevenly contact, then manufacturing is easier, but performance, strength, and operation noises are negatively influenced
Solution Approach 1:
The invention creates equipotentiality in the force distribution by ensuring that the reaction force is received at the same axial position where the load is applied. This eliminates moment-induced inclination and ensures uniform contact pressure distribution across the gear tooth surfaces, achieving both even contact and manufacturing feasibility.
Data Source
AI summary
A disc brake including a planetary gear speed reduction mechanism that improves the meshing condition of gears at activation. A sun gear (84) of a planetary gear speed reduction mechanism (55) employed in the disc brake includes a cylindrical supporting portion (112) configured to rotatably support a sun gear (82), an annular wall portion (111) disposed to face a large gear (88) at predetermined distance away in the axial direction of the large gear, and a reaction force receiving portion (114) disposed to overlap with the large gear as viewed from the radial direction of the large gear and configured to receive a reaction force produced by rotation of the sun gear (82). This improves the meshing condition of the planetary gear speed reduction mechanism and represses negative influences on performance, strength, operation noises and the like associated with transmission of rotation torque.