Multiturn Angle Encoder Gear With Embedded Magnets
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Solution Overview
Problem
Existing multiturn angle measuring devices face issues with complex backlash-prone reduction gears, non-compact structures due to separate permanent magnet attachments, high assembly efforts, and play-related inaccuracies in magnet placement.
Innovation Solution
Integration of permanent magnets directly into the gear wheels via overmolding, with snap-in locks and magnetic conductive axes for secure and play-free alignment, and a two-story printed circuit board arrangement for compactness and reduced assembly complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If permanent magnets are attached separately above gear wheels with brackets, then the structure is modular and assembly is flexible, but the structure becomes non-compact and play is introduced in the attachment
Solution Approach 1:
The patent merges the permanent magnets with the gear wheels by integrating them directly into the gear wheel structure. The magnets are embedded in the gear wheels during the injection molding process, eliminating the need for separate brackets and attachment mechanisms. This integration reduces the overall height and creates a compact structure while maintaining manufacturing efficiency through a single-step production process.
2Ease of manufacture
If permanent magnets are glued to the code carrier outside the transmission structure, then assembly is simple, but the structure becomes non-compact and glue failure risk increases over service life
Solution Approach 1:
The patent applies preliminary action by embedding the permanent magnets into the gear wheels during the injection molding process itself, before the gear wheels are assembled into the transmission structure. This preliminary integration ensures that the magnets are permanently secured within the gear wheel material, eliminating any risk of glue failure or magnet loss during the device's service life.
3Productivity
If a complex reduction gear with worm wheel is used for multiturn detection, then gear reduction is achieved, but backlash and rapid wear occur due to considerable play between gear wheels
Solution Approach 1:
The patent replaces the complex mechanical reduction gear system with a magnetic field-based detection system. Instead of using multiple gear wheels with permanent magnets attached, the invention uses a single gear wheel with an integrated permanent magnet and detects gear position through Hall sensors that measure changes in the magnetic field. This substitution eliminates backlash and wear associated with traditional mechanical gear systems while maintaining the gear reduction capability.
4Volume of moving object
If optical single-turn scanning and magnetic multi-turn scanning are arranged on opposite sides of a printed circuit board, then a compact structure is achieved, but the structure can be further minimized
Solution Approach 1:
The patent merges the magnetic scanning components by integrating the permanent magnet directly into the gear wheel structure. This integration allows the magnetic field to be generated at the optimal position for sensor detection, enabling both optical and magnetic scanning functions to be arranged more compactly on the same side of the printed circuit board or in closer proximity, thereby minimizing the overall device volume.
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
The solution results in a compact, cost-effective, and accurate multiturn angle measuring device with reduced assembly risks and precise magnetic force consistency, ensuring constant distance and magnetic field strength over the device's lifespan.
Implementation Method 1
the axle consists of a magnetically conductive material, so that there is a constant mutual attraction between the permanent magnet embedded below the axle and at a small distance from the front side of the axle and the magnetically conductive material of the fixed axle
Implementation Method 2
a precise distance to a Hall element arranged underneath is to be provided
Data Source
Figure 1~3
Figure 4~5
Figure 6~7
AI summary
The invention relates to a multi-turn angle measurement device for measuring multiple revolutions of a shaft (4), consisting of a first code carrier (31) with an optical single-turn scanning function (34) for detecting the absolute position of the shaft and a second code carrier for measuring the number of revolutions of the shaft (4). A reduction gear (2) is arranged between the first code carrier (31) and the second code carrier, and the second code carrier consists of a number of permanent magnets (22), the position of which is detected by an assembly of Hall sensors (16a-16b) fixed to the housing. Each of the permanent magnets (22) is embedded into the plastic material of the transmission gears (20) of the reduction gear (2).