Integrated Bearing Strain Element for Compact Torque Detection
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Solution Overview
Problem
Existing torque detectors with strain elements require additional space and components for attachment, making them less compact and increasing the number of components, which hinders their integration into motors, reducers, and rotary propulsion units.
Innovation Solution
A bearing unit with a cross roller bearing and integrated strain element, where the strain element and inner race are formed as a single component, eliminating the need for separate attachment space and components, and allowing for compact and lightweight design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a strain element is attached between the internally toothed gear and unit housing using separate components and fastening fittings, then the torque detection function is achieved, but the installation space increases and the number of components increases
Solution Approach 1:
The strain element is integrated into the inner race of the cross roller bearing, merging two previously separate components (strain element and bearing race) into a single unified structure. This integration eliminates the need for separate attachment components and fastening fittings, directly reducing the number of parts while maintaining torque detection functionality through the strain element's ability to detect circumferential displacement
2Measurement precision
If a strain element is attached between the internally toothed gear and unit housing using separate components and fastening fittings, then the torque detection function is achieved, but the installation space increases
Solution Approach 1:
The strain element is merged with the inner race of the cross roller bearing, creating a compact integrated structure that eliminates the need for separate attachment space. The strain element is positioned within the bearing's internal geometry, utilizing existing structural space rather than requiring additional installation volume
3Measurement precision
If additional attachment components and fastening fittings are used to attach the strain element, then the torque detection function is achieved, but the unit weight increases
Solution Approach 1:
The strain element and inner race are combined into a single component, eliminating the weight of separate attachment components and fastening fittings. The integrated design removes unnecessary material while preserving the strain element's torque detection capability through its placement within the bearing structure
4Device complexity
If the strain element is integrated into the bearing unit, then the number of components is reduced and the design becomes more compact, but the manufacturing complexity increases
Solution Approach 1:
The bearing unit is designed with modular segmentation, where the strain element is integrated into the inner race as a distinct functional zone. This segmentation allows the strain element to be manufactured as part of the bearing assembly using standard bearing manufacturing processes, minimizing the increase in manufacturing complexity while achieving component reduction
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
This integration enhances torque detection precision by reducing thermal strain and assembly inaccuracies, and eliminates the need for additional fastening components, resulting in a more compact and precise torque detection system.
Implementation Method 1
strain produced in the strain element is measured by a strain gauge or another detection element, and torque exerted on the rotating shaft from the load-side member is detected
Implementation Method 2
a cross roller bearing provided with an outer race, an inner race, and a plurality of cylindrical rollers inserted in a rollable state between the races
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(b)
Figure 3
AI summary
A bearing unit (1) is provided with a strain element (6) for torque detection. The strain element (6) is provided with a first annular part (7) attached to a rotation-side member, a second annular part (8) attached to a load-side member, and a plurality of ribs (9) serving as strained parts linking the first annular part (7) and the second annular part (8) together. One of an inner race (4) and an outer race (3) is integrally formed on the first annular part (7) of the strain element (6). Deformation, which occurs in the ribs (9) of the strain element (6) due to torque exerted on the rotation-side member from the load-side member, is detected by a strain gauge, etc., and converted to torque. The strain element for torque detection can be incorporated into a motor, a reducer, or another rotary propulsion unit without the need for a dedicated installation space and without the need for fastening fittings, etc.