Planetary Roller Bearing for Compact High-Load Turntables
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Solution Overview
Problem
Existing rotary table devices in machine tools face limitations in achieving high load capacity with minimal installation space due to the load capacity being restricted by point or line contact between rolling elements and bearing raceways, leading to the need for large rolling element diameters and increased space usage.
Innovation Solution
A rotary table device utilizing a single planetary roller bearing with integrally inserted groove profiles on bearing rings and distributed planetary rolling elements, allowing for multiple supporting surfaces and improved load capacity, along with optional features like axial preload and a measuring device for rotational characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If separate roller bearings with point or line contact are used, then the bearing structure is simple and easy to manufacture, but the load capacity is limited and requires large rolling element diameters increasing installation space
Solution Approach 1:
The patent transitions from point or line contact in traditional bearings to surface contact through groove profiles on planetary rolling bodies. This dimensional change from 0D/1D contact to 2D surface contact dramatically increases load capacity while reducing the required bearing size, directly resolving the contradiction between load capacity and installation space.
Solution Approach 2:
The bearing is divided into multiple planetary rolling bodies distributed around the circumference, each with groove profiles. This segmentation allows the load to be distributed across multiple supporting surfaces simultaneously, increasing overall load capacity while keeping individual rolling body dimensions small, thus reducing installation space.
2Force
If large rolling element diameters are used to achieve high load capacity, then the load bearing capability increases, but the installation space and device complexity increase
Solution Approach 1:
The bearing structure is segmented into multiple smaller planetary rolling bodies with groove profiles instead of one or few large rolling elements. This segmentation achieves high load capacity through distributed surface contact while keeping individual components compact and the overall structure manageable, reducing device complexity.
Solution Approach 2:
The planetary rolling bodies with groove profiles are nested within a compact bearing arrangement, with multiple rows of rolling bodies accommodated in a limited radial and axial space. This nesting approach maximizes load capacity within a small footprint, avoiding the need for large rolling element diameters.
3Manufacturing precision
If multiple rows of planetary rolling bodies are arranged axially, then the load capacity and coaxial accuracy improve, but the axial dimension and installation space increase
Solution Approach 1:
The patent introduces axial offsets between groove profiles of different rows and incorporates pitch errors in the groove profiles to create axial prestress. This parameter change allows multiple rows to be arranged in a compact axial space while maintaining high coaxial accuracy through controlled preload, resolving the contradiction between precision and axial dimension.
Solution Approach 2:
Axial prestress is applied through pitch errors and groove profile offsets before the bearing enters service. This preliminary action pre-loads the multiple rows of planetary rolling bodies, ensuring high coaxial accuracy and load capacity while minimizing the required axial dimension by eliminating the need for larger clearance designs.
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 solution enables the design of compact rotary table bearings with high load capacity and improved coaxial accuracy, allowing for efficient mounting and operation with reduced space requirements and enhanced rotational characteristics monitoring.
Implementation Method 1
By meshing the groove profiles of the bearing rings with the outer profiles of the planetary rolling bodies, an axially fixed and radially rotatable bearing is formed, in which a large number of supporting surfaces are formed between the bearing rings
Implementation Method 2
Planetary rolling elements with an outer profile that complements the groove profiles are distributed over the circumference between the bearing rings. By meshing the groove profiles of the bearing rings with the outer profiles of the planetary rolling bodies
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a rotary table bearing device (1) for supporting a rotary table in a rotatable and axially fixed manner with respect to a stationary frame by means of a roller bearing. In order to develop a rotary table bearing device (1) simply and with a high load rating, the roller bearing is formed by a single planetary roller bearing (2). The single planetary roller bearing (2) has two bearing rings (3, 4), one of which is associated with the frame and the other of which is associated with the rotary table and which have grooved profiles (7, 8), and planetary rolling elements (10), which are arranged in such a way that the planetary rolling elements are distributed over the circumference and which have an outer profile (11) that is complementary to the grooved profiles (7, 8).