Helical Planetary Reduction Gear With Preloaded Sun Gear Support
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Solution Overview
Problem
Conventional planetary reduction gears with helical gears face issues with sun gear displacement due to thrust forces, leading to inaccurate rotational motion and increased angle error, and existing solutions like dual thrust bearings increase axial dimensions, making them unsuitable for space-constrained installations.
Innovation Solution
A compact planetary reduction gear design featuring a cylindrical housing with a front-stage and rear-stage planetary gear mechanism, where the sun gear is supported by a radial or thrust bearing and a preload mechanism, including a set screw, to prevent axial displacement without increasing axial dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dual thrust bearings are used to suppress sun gear displacement, then axial displacement is reduced, but axial dimensions increase
Solution Approach 1:
The invention combines the support function of two separate thrust bearings into a single thrust bearing, while using a preload mechanism to achieve the same displacement suppression effect. This merging reduces the axial dimension by eliminating one bearing and its associated clearance, while the preload mechanism maintains positioning accuracy through controlled preloading.
Solution Approach 2:
The preload mechanism applies a preliminary axial force to the single thrust bearing before operation, pre-compressing it to eliminate internal clearance. This preliminary action ensures that the sun gear is firmly positioned without requiring the additional axial space of dual bearings, resolving the contradiction between precision and compactness.
2Manufacturing precision
If bearings with internal gap are used to support sun gear, then axial displacement is reduced, but angle error increases
Solution Approach 1:
The preload mechanism applies a preliminary axial force to the thrust bearing, pre-compressing it to eliminate internal clearance before the gear mechanism operates. This preliminary action ensures that no axial play or angle error occurs during operation, as the bearing is already in a pre-loaded state that prevents any clearance-related positioning errors.
Solution Approach 2:
The preload mechanism creates a preliminary compressive force that counteracts any potential axial displacement or clearance effects during operation. By applying this counteracting force in advance, the system prevents the occurrence of angle errors that would otherwise result from bearing internal gap, thereby maintaining high rotational accuracy.
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
The design effectively suppresses sun gear displacement and angle error, maintaining rotational accuracy while reducing axial dimensions, thus providing a space-efficient and reliable solution.
Implementation Method 1
a preload mechanism that applies preload to the second bearing in a direction along the center axis towards the first bearing
Implementation Method 2
The rear-stage internal gear, the rear-stage sun gear and the rear-stage planetary gear are helical gears, respectively
Data Source
AI summary
A planetary reduction gear using a helical gear is configured such that a rear-stage sun gear is rotatably supported by a device housing via a radial bearing on one side in the direction of a center axis, and is rotatably supported by a rear-stage planetary carrier via a thrust bearing on the other side. The rear-stage planetary carrier is rotatably supported by the device housing via a rear-stage carrier bearing. A preload is applied to the thrust bearing by a preload mechanism mounted to the rear-stage planetary carrier. Displacement of the rear-stage sun gear caused by a thrust force generated due to engagement with a rear-stage planetary gear can be suppressed, and an angle error between input rotation and output rotation can be suppressed.