Slip ring wear indication via segmented encoder counters
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Solution Overview
Problem
Existing slip rings face challenges in reliably indicating wear, especially in discontinuously operating devices like industrial robots, where wear distribution varies across sections, making traditional wear indication methods unreliable.
Innovation Solution
A slip ring unit with a mechanically coupled encoder for detecting relative angular position between the sliding track and brush, combined with an evaluation unit that generates wear indication signals based on position data, and includes wear counters for specific angular sections, optionally considering speed and acceleration, and auxiliary sensors for operational values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional wear indication methods (measuring brush length or electrical parameters) are used, then the system is simple to implement, but the wear indication is unreliable for discontinuously operating devices with non-uniform wear distribution
Solution Approach 1:
The sliding track is divided into multiple angular sections, each with its own wear counter. The encoder is also segmented into multiple detection positions around the circumference. This segmentation allows independent monitoring of wear in different angular sections, enabling reliable detection of non-uniform wear patterns that occur in discontinuously operating devices.
Solution Approach 2:
An encoder is introduced as an intermediary component between the sliding track and the evaluation unit. The encoder mechanically couples to both the sliding track and the brush, detecting relative angular position and enabling the system to track which angular sections are currently under load. This intermediary provides the data needed to generate position-dependent wear indications without requiring direct measurement of wear itself.
2Measurement precision
If wear indication is based on electrical parameters like contact resistance or contact noise, then no additional mechanical components are needed, but the measurement precision is insufficient for early wear detection
Solution Approach 1:
The patent replaces electrical parameter measurement with a mechanical encoding system. Instead of measuring electrical contact resistance or noise, the system uses a mechanical encoder to detect angular position and a mechanical wear counter to track wear events. This substitution provides more precise and earlier wear detection because it directly monitors the mechanical wear process rather than inferring it from electrical properties that change only after significant wear has occurred.
3Reliability
If the encoder monitors the entire rotation continuously, then complete wear data is captured, but the device complexity and data processing requirements increase significantly
Solution Approach 1:
The evaluation unit focuses monitoring efforts on specific angular sections where wear is most likely to occur or where the device operates most frequently. Each angular section has its own wear counter that is independently updated based on encoder position signals. This local quality approach ensures complete wear monitoring while reducing data processing complexity by treating each section independently rather than analyzing continuous rotation data as a whole.
Data Source
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AI summary
A slip ring unit comprises a brush block with multiple brushes rotatable against a module with multiple sliding tracks. An angular encoder is connected to the brush block and the module for detecting the relative position in between. An evaluation unit receives signals from the position encoder and generates a position dependent wear indicating signal thereof. It has multiple wear counters as- signed to multiple positions and/or sections. If a movement is detected within a certain section, the related wear counter is incremented. This allows to monitor wear at slip rings which are not continuously rotating.