Magnetic field structure for magnetic induction gear encoder

Abstract

The invention discloses a magnetic field structure for a magnetic induction gear encoder. The magnetic field structure comprises a gear encoding disc and an inductive head, a sensor and a permanent magnet are installed in the inductive head, the sensor is located right above the tooth top of the gear encoding disc, the axial deviation between the permanent magnet and the center line y of the sensor inside the inductive head is t, the t is smaller than or equal to 5 mm, the radial deviation between the side, with the edge close to the sensor, of the permanent magnet and the center line z of the sensor is h, the h is larger than or equal to -3 mm and smaller than or equal to 3 mm, a skewing angle formed between the end face of the permanent magnet and the xy plane is alpha, the alpha is larger than or equal to -38 degrees and smaller than or equal to 38 degrees, a skewing angle formed between the end face of the permanent magnet and the xz plane is beta, and the beta is larger than or equal to -36 degrees and smaller than or equal to 36 degrees. By means of the magnetic field structure for the magnetic induction gear encoder, the encoder sensitivity is higher, the accuracy can reach the level that the module0.3 can be accurately distinguished, and the tooth distance capable of being distinguished is smaller than or equal to 0.94 mm; compared with an encoder with the same resolution ratio, the size is smaller, the structure is more compact, the externally-expressed magnetism is weaker, scrap iron is not prone to being absorbed, and a scrap iron protection device is avoided.

Description

technical field [0001] The invention relates to the technical field of encoders, in particular to a magnetic field structure for a magnetic induction gear encoder. Background technique [0002] The magnetic ring encoder in the prior art is composed of an induction head and a magnetic ring encoder disk, and the magnetic ring encoder disk is processed by injection molding, die-casting or casting by ferromagnetic material powder and plastic material as a binder. Formed, and then the outer ring is evenly magnetized into small magnetic moments connected in series by magnetization, such as image 3 Shown, and with a certain mechanical package to install on the measured shaft, such as Figure 4 shown. When the motor with a magnetic ring encoder disk makes a circular motion, when each small magnetic moment rotates from far to near and approaches the induction, different magnetic field strengths and gradients will be generated. The built-in magnetic sensor of the induction head will...

AI Technical Summary

Problems solved by technology

[0005] The method that takes at present is that sensor 12 is positioned between permanent magnetic field 11 and gear 13, as Figure 5 and Image 6 As shown, this method can distinguish module 0.4 with the highest accuracy, and can effectively subdivide module 0.4 to 100, that is, 100 times frequency output, but the smaller recognition distance has not been broken through. If module 0.3 is achieved, because it is Using the strong magnetic method, the strong magnetism is easy to attract some ferromagnetic powders, the accumulation of fine powders to a certain extent will cause measurement errors, and the larger small iron pieces will cause collision damage or splashing and hurt people, so the strong magnetic encoder needs to be added. Some protective measures, especially to prevent the larger ferromagnetic particles from entering the gap between the sensor and the relative movement of the gear, the encoder is large in size, not compact in structure, and has strong magnetic properties externally, posing safety hazards

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