Slewing Ring Integrated Motor Axial Positioning Accuracy
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Solution Overview
Problem
Existing slewing rings with integrated rotation motors face precision issues due to the sensor's distance from the bearing, leading to measurement inaccuracies and mechanical limitations in handling varying speeds and loads, as well as reliability concerns with cumbersome marking strip arrangements.
Innovation Solution
The slewing ring design features a marking strip and magnets positioned axially adjacent to the rolling elements, with all peripheral zones machined on the same machine to ensure optimal concentricity and precision, using a single row of angular contact rollers and a compact motor layout with a structural frame for cooling, allowing for precise torque control and high rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the sensor is positioned far from the bearing to accommodate the rotation motor, then the motor can be integrated into the slewing ring, but measurement accuracy deteriorates due to increased radial runout
Solution Approach 1:
The patent transitions the positioning system from a radial arrangement (sensor far from bearing) to an axial arrangement (marking strip axially adjacent to rolling elements). This dimensional change allows the sensor to be positioned close to the bearing axially rather than radially, reducing radial runout while maintaining motor integration capability.
Solution Approach 2:
The patent introduces a marking strip as an intermediary element positioned on the rotating ring, axially adjacent to the rolling elements. This marking strip serves as a reference for the sensor, enabling accurate position measurement without requiring the sensor to be physically close to the bearing, thus resolving the conflict between motor integration and measurement accuracy.
2Device complexity
If the marking strip is positioned far from the rolling elements, then the rotation motor can be accommodated, but positioning accuracy deteriorates due to ring deformation during operation
Solution Approach 1:
The patent applies local quality by positioning the marking strip in a specific location axially adjacent to the rolling elements, where it is least affected by ring deformation during operation. This localized positioning ensures high positioning accuracy while accommodating the rotation motor elsewhere in the structure.
3Ease of manufacture
If multiple peripheral zones are machined on different machines, then assembly is more flexible, but concentricity and precision deteriorate due to accumulated tolerances
Solution Approach 1:
The patent merges the machining operations for multiple peripheral zones (bearing raceway, marking strip support, and motor mounting zone) into a single machining process. By machining all zones on the same machine in one setup, the patent eliminates accumulated tolerances and ensures optimal concentricity between all components, while maintaining assembly flexibility through the integrated design.
4Adaptability or versatility
If a cumbersome marking strip arrangement is used, then the rotation motor can be integrated, but reliability deteriorates
Solution Approach 1:
The patent extracts the marking strip from the cumbersome radial arrangement and repositions it axially adjacent to the rolling elements. This extraction and repositioning eliminates the reliability issues associated with far-distance sensor positioning while maintaining motor integration capability.
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 configuration enhances positioning accuracy, reduces assembly tolerances, and supports heavy loads with minimal backlash, providing a lightweight, cost-effective solution with improved stability and reliability under demanding conditions.
Implementation Method 1
two rings mounted to rotate relative to each other by means of rolling elements arranged annularly
Implementation Method 2
a position sensor adapted to cooperate with the strip
Implementation Method 3
a rotor part fixed to the other ring and comprising magnets arranged on its periphery
Implementation Method 4
rotation motor comprising a stator part fixed to one of the rings, which is fixed, and a rotor part fixed to the other ring
Implementation Method 5
a cooling circuit
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The ring (1) has an integrated rotary electric motor (5) including a stator part (5a) fixed at a fixed collar (9), and a rotor part (5b) fixed at another rotary collar. The rotary collar includes a machined periphery zone (11b) receiving a support for a locating unit that locates an angular position of the rotary collar with respect to the fixed collar, and another periphery zone (11c) receiving a support for magnets (5b1) of the rotor part. The zones are arranged in a manner such that the zones define a support for an angular position locating band and the magnets, respectively.