Spindle And Rotary Table Position Sensing for Axis Tilt Measurement
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Solution Overview
Problem
Current measuring devices for spindles and rotary tables lack the precision and multi-directional capability to accurately determine the position of the axis of rotation during operation, especially under operating loads, which affects the performance and accuracy in machining and measuring processes.
Innovation Solution
A measuring device with at least two first position sensing elements and two second position sensing elements, along with a scale element featuring distinct graduations, allows for the determination of the axis of rotation's position in multiple directions by scanning regular structures arranged in parallel to the circumferential and axial directions, enabling absolute angular and axial position measurements with high resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single position sensing element is used, then the device complexity is low, but the measurement precision and multi-directional capability are insufficient
Solution Approach 1:
The scale element is divided into two independent graduations (first and second graduations) with different orientations. The first graduation has structures arranged parallel to the circumferential direction for angular position measurement, while the second graduation has structures arranged parallel to the axial direction for axial position measurement. This segmentation allows each sensing element to specialize in one measurement direction, achieving high precision without requiring an overly complex sensor array.
Solution Approach 2:
The invention transitions from single-direction measurement to multi-directional measurement by adding a second graduation dimension. The first graduation measures in the circumferential dimension while the second graduation measures in the axial dimension. This dimensional expansion enables the scale element to provide position information in multiple directions simultaneously, resolving the contradiction between measurement capability and device complexity.
2Measurement precision
If only incremental graduation is used, then the device structure is simple, but the absolute position determination across rotations cannot be achieved
Solution Approach 1:
The invention merges incremental graduation and absolute code track into a single scale element. The incremental graduation provides high-resolution position changes, while the absolute code track provides absolute position reference across rotations. This combination allows the system to determine both incremental changes and absolute positions without requiring separate sensing systems, achieving accurate absolute position determination while maintaining relatively simple device structure.
3Adaptability or versatility
If the scale element is rigidly fixed, then the manufacturing precision is high, but the adaptability to operating loads and tilting measurement is reduced
Solution Approach 1:
The scale element is designed with dynamic characteristics that allow it to tilt relative to the shaft during operation. This tilting capability enables the scale element to adapt to operating loads and gravitational effects, maintaining measurement accuracy under varying conditions. The dynamic design allows the scale element to self-adjust its orientation while the sensing elements continue to accurately measure position changes, resolving the contradiction between adaptability and manufacturing precision.
Data Source
AI summary
A measuring device for a spindle or for a rotary table includes at least two first and second position sensing elements and a scale element, having a first and second graduations and being rotatable about an axis of rotation relative to the position sensing elements. The first graduation includes regular structures arranged in parallel next to one another along a first direction, having a directional component in the circumferential direction. The second graduation includes regular structures arranged in parallel next to one another along a second direction, having a directional component in the axial direction. The first position sensing elements are offset from one another in the circumferential direction, and are able to scan the first graduation so that the position of the scale element in a plane having an orthogonal orientation to the axis of rotation is determinable. In addition, at least one of the first position sensing elements is able to determine an angular position of the scale element in relation to the first position sensing elements in absolute terms within and across a rotation. The second position sensing elements are offset from one another in the circumferential direction, and are able to scan the second graduation, and the axial position of the scale element is able to be determined.