Three-Ring Bearing Test Stand for Accurate Friction Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for testing bearings, such as wheel bearings in motor vehicles, are not cost-effective or simple, as they often involve complex setups and inaccuracies due to frictional interference in hydrostatic or hydrodynamic systems.
Innovation Solution
A test stand utilizing a three-ring bearing with a rotatable intermediate ring, driven by a motor, which minimizes friction by operating in the transition region between mixed and liquid friction, allowing for accurate measurement of frictional forces by canceling out interference from the holding bearing's friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a hydrostatic or hydrodynamic plain bearing is used to support the bearing under test, then the bearing can be supported with minimal power loss, but the system becomes complex and costly due to oil pressure control requirements
Solution Approach 1:
The patent replaces expensive, complex hydrostatic bearings with a simple three-ring bearing assembly that uses inexpensive rolling elements. The three-ring bearing consists of an inner ring, outer ring, and intermediate ring with rolling elements between the inner and outer rings, eliminating the need for costly hydrostatic oil pressure control systems while maintaining low friction characteristics
Solution Approach 2:
The patent substitutes the hydrostatic mechanical system (requiring fluid pressure control) with a rolling contact mechanical system. The three-ring bearing uses rolling elements to reduce friction, replacing the complex fluid-dynamic mechanism with a simpler solid-mechanics-based solution that achieves similar power loss reduction without the accompanying complexity
2Reliability
If a holding bearing is used to introduce test force into the bearing under test, then the bearing can be properly supported, but friction in the holding bearing distorts measurement results
Solution Approach 1:
The holding bearing is segmented into three separate rings (inner ring, outer ring, and intermediate ring) with rolling elements between them. This segmentation allows the friction to be isolated to specific interfaces and enables the intermediate ring to rotate independently, minimizing the frictional influence on measurements while maintaining proper bearing support
Solution Approach 2:
The intermediate ring is made rotatable relative to the inner and outer rings, introducing dynamic movement to the previously static holding bearing structure. This rotation capability allows the intermediate ring to overcome static friction and operate in a regime where friction is minimized and more predictable, reducing distortion of measurement results
3Measurement precision
If static friction in the three-ring bearing is overcome by rotating the intermediate ring, then friction is minimized, but additional complexity is introduced with the drive motor
Solution Approach 1:
The intermediate ring's rotation is designed to be self-servicing in the sense that once started, the rotation continues with minimal additional energy input to maintain operation in the low-friction regime. The drive motor only needs to overcome static friction initially, after which the system maintains itself in the desired operational state with minimal control 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
Enables cost-effective and straightforward testing of bearings by isolating the frictional force of the bearing under test from the holding bearing's friction, ensuring accurate measurement and easy adaptation to different bearing sizes.
Implementation Method 1
The intermediate ring can be rotated at an angular velocity at which static friction between the intermediate ring and the support rings or intermediate rolling elements is overcome. In particular, the intermediate ring can be rotated at an angular velocity at which the intermediate ring operates in the transition range between mixed friction and fluid friction, particularly near the release point, which corresponds to the minimum of the Stribeck curve.
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The invention relates to a stand (10) for testing a bearing (18), provided with a rotatable drive flange (24) for driving a first bearing ring (20) of the bearing (18) to be tested and a holding bearing (14) for supporting the bearing (18) to be tested and for introducing a testing force into the bearing (18) to be tested. The holding bearing (14) is designed as a three-ring bearing with a first support ring (30) which can be secured to a second bearing ring (26) of the bearing (18) to be tested, said second bearing ring being rotatable relative to the first bearing ring (20), a second support ring (33) which is secured in a rotationally fixed manner, and an intermediate ring (32) which is mounted between the first support ring (30) and the second support ring (33) in a relatively rotatable manner. The intermediate ring (32) is coupled to a drive motor (34) in order to rotate the intermediate ring (32) relative to the first support ring (30) and the second support ring (33). By virtue of the intermediate ring (32) which can be rotated in different directions, an inexpensive and simple testing of bearings (18) is facilitated.