Magnetic Scale Cover for Motion Guide Iron Powder Scraping
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Solution Overview
Problem
Magnetic scales in motion guide apparatuses attract iron powder, leading to reduced measurement accuracy and potential wear or deformation when attempting to scrape off adhered iron powder with a scraper or seal.
Innovation Solution
A magnetic-scale-equipped motion guide apparatus with a cover member that covers the magnetic scale and through holes, allowing iron powder on the cover member to be scraped without direct contact with the magnetic scale, preventing wear and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a magnetic scale is exposed on the upper surface of the track rail to enable reading, then the reading head can access the magnetic pattern, but iron powder adheres to the magnetic scale surface and side surfaces, reducing measurement accuracy
Solution Approach 1:
A non-magnetic cover member is introduced as an intermediary between the iron powder environment and the magnetic scale. The cover member has a through hole that allows the reading head to access the magnetic pattern while the cover itself protects the magnetic scale from iron powder adhesion, thus maintaining measurement accuracy while enabling operation
2Object-affected harmful factors
If a scraper or seal is used to remove iron powder from the track rail surface, then iron powder can be scraped off, but the scraper or seal contacts the magnetic scale causing wear and deformation
Solution Approach 1:
The non-magnetic cover member serves as a mediator that allows the scraper or seal to remove iron powder from the track rail surface and the cover itself, while preventing direct contact with the magnetic scale. This enables effective iron powder removal without compromising the magnetic scale's integrity
Solution Approach 2:
The harmful interaction between the scraper/seal and the magnetic scale is extracted by removing the magnetic scale from the contact zone. The cover member isolates the magnetic scale from the scraping operation, allowing iron powder removal to proceed without affecting the magnetic scale
3Measurement precision
If the magnetic scale is covered to protect from iron powder, then measurement accuracy is maintained, but the reading head cannot access the magnetic pattern
Solution Approach 1:
The cover member is segmented with a through hole that selectively opens only where the reading head needs to access the magnetic pattern. This segmentation allows the cover to protect the magnetic scale from iron powder while maintaining accessibility for the reading head through the opening
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
Prevents adverse effects such as wear and deformation on the magnetic scale while maintaining high measurement accuracy by covering the magnetic scale and through holes with a non-magnetic cover member, allowing effective scraping of iron powder.
Implementation Method 1
The magnetic scale is a scale having a fine magnetic pattern where the north and south poles are alternately arranged to detect the magnetic flux density of the magnetic pattern by a magnetometer such as a Hall sensor or a magnetoresistive element
Data Source
AI summary
A magnetic-scale-equipped motion guide apparatus is provided which can scrape iron powder adhered to a magnetic scale by a scraper or seal of a movable member without inviting adverse effects such as wearing away and deformation of the magnetic scale. The magnetic-scale-equipped motion guide apparatus of the present invention comprises a track member 1 having a rolling element rolling portion 1b and also an upper surface where through holes 18 into which fastening members are inserted open, a movable member 2 movably assembled to the track member 1 via a plurality of rolling elements 3, a groove 1a formed in the track member 1 and extended in a longitudinal direction, a magnetic scale 7 accommodated in the groove 1a and having north and south poles alternately formed in the longitudinal direction, and a cover member 8 that covers the magnetic scale 7 and also the through holes 18 of the track member 1.