Gear Measuring Device Calibration Using Tooth Profile Gradient Errors
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Solution Overview
Problem
Conventional gear measuring devices require mechanical reference members for calibration, which increases setup and teardown time and costs, especially when dealing with large gears, due to the need for additional space and precise alignment.
Innovation Solution
A method that calibrates the gauge head of a gear measuring device using arithmetic processing based on tooth profile gradient errors obtained from two different scanning directions, eliminating the need for mechanical reference members by calculating the position error and adjusting the gauge head's position accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mechanical reference member (reference block, test bar, or master work) is used for calibration, then the position of the gauge head can be calibrated with high precision, but the setup and teardown time increases and additional space is required
Solution Approach 1:
The workpiece gear itself is used as the reference for calibration. The gauge head measures the tooth profile of the workpiece gear, and the measured data is used to calculate and correct the gauge head position error. This eliminates the need for separate mechanical reference members and reduces setup time.
Solution Approach 2:
The calibration function is extracted from the traditional mechanical reference member approach and integrated into the measurement process itself. The system uses the workpiece gear's own tooth profile characteristics to perform self-calibration, removing the dependency on external reference objects.
2Measurement precision
If a mechanical reference member is used for calibration, then calibration precision can be maintained, but device complexity and costs increase due to additional components
Solution Approach 1:
The workpiece gear serves dual purposes: it is both the object to be measured and the reference standard for calibration. This multi-functionality eliminates the need for dedicated reference members and simplifies the overall system structure.
Solution Approach 2:
The separate calibration reference member is removed from the system entirely. The calibration functionality is extracted and integrated into the measurement process by using mathematical processing of the workpiece gear's own tooth profile data.
3Measurement precision
If thermal deformation occurs in the gear measuring device, then measurement accuracy deteriorates, but using mechanical reference members requires additional space and alignment precision
Solution Approach 1:
The workpiece gear performs self-calibration by using its own tooth profile as the reference. This eliminates the need for external reference members that would require additional space and precise alignment, particularly important when measuring large gears.
Data Source
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AI summary
A difference of tooth profile gradient errors (Δα) is calculated, which is a deviation between the tooth profile gradient error (α1) when the tooth profile of a gear is calculated by a method of scanning in a tangential direction of a base circle; and the tooth profile gradient error (α2) when the tooth profile of a gear is calculated by scanning methods other than a method of scanning in a tangential direction of a base circle. The position error (Δx) is calculated using the difference of tooth profile gradient errors (Δα) and gear specifications, and the position of the gauge head is calibrated depending on the position error (Δx). Hereby the position of the gauge head can be calibrated without using a mechanical reference member.