Anti-magnetic interference encoder

Abstract

The utility model discloses an anti-magnetic interference encoder, and relates to the field of encoders. The utility model discloses an anti-magnetic interference encoder, which comprises a shell, a reading head and a magnetic wheel disc, and is characterized in that the reading head comprises a PCB (printed circuit board) fixed in the shell; the magnetic wheel disc comprises a PCB, a plurality of sensing elements arranged on the PCB, and a transmission mechanism which is parallel and right opposite to the PCB; the permanent magnets are fixedly connected with the transmission mechanism; and the plurality of magnetic conductive sheets are fixedly connected with the permanent magnet. According to the utility model, the problems that a magnetoelectric encoder is sensitive to external magnetic interference and errors are easy to generate are solved, so that the magnetic encoder can adapt to a working environment with electromagnetic interference, and the magnetoelectric encoder has the characteristics of economy, practicability, high detection precision and compact structure.

Description

Technical Field

[0001] The utility model relates to the field of encoders, in particular to an encoder resistant to magnetic interference. Background Art

[0002] A magnetic encoder is a device that uses the principle of magnetic field to measure angles or displacements. Its working principle is based on the magnetoelectric effect, and it measures rotational or linear displacements by detecting changes in the magnetic field.

[0003] In the prior art, the structural connection method of a magnetic encoder mainly involves two core parts: a reading head and a magnetic wheel disc. The reading head is fixed on the PCB, while the magnetic wheel disc is connected to the object to be measured and moves with it. The reading head contains one or more sensing elements (such as Hall effect sensors, magnetic induction chips, etc.) for detecting changes in the nearby magnetic field. The magnetic wheel disc has north and south pole magnets installed on the transmission mechanism. When the wheel disc rotates, these magnets approach or move away from the reading head, thereby changing the magnetic field intensity around it. By detecting this change, the position and motion state of the wheel disc relative to the reading head can be determined.

[0004] However, magnetic encoders are relatively sensitive to external magnetic interference and are prone to errors. Especially in some application scenarios, there is another strong magnetic field in the surrounding environment, which seriously affects the reading head's judgment of the magnitude of the surrounding magnetic field intensity. For example, when the motor itself has a braking function, an electromagnetic field is generated when powered on; there is a storage space with a strong magnet in the surrounding environment; there are installation environments with equipment such as transformers, radio antennas, and microwave ovens. Summary of the Utility Model

[0005] To solve the above problems, the utility model provides an encoder resistant to magnetic interference, which includes a housing, a reading head, and a magnetic wheel disc. The reading head includes: a PCB board, which is fixedly connected to the inside of the housing; several sensing elements, which are arranged on the PCB board; the magnetic wheel disc includes: a transmission mechanism, which is parallel and facing the PCB board; several permanent magnets, which are fixedly connected to the transmission mechanism; several magnetic conductive sheets, which are fixedly connected to the permanent magnets; the number of the sensing elements, the permanent magnets, and the magnetic conductive sheets is equal.

[0006] Preferably, the sensing element is one of a magnetic induction chip, a Hall effect sensor, and a magnetoresistive sensor.

[0007] Preferably, the housing includes a cover plate and an outer cover.

[0008] Preferably, the material of the magnetic conductive sheet is selected from one of nickel-iron magnetic alloy, soft iron, high-permeability alloy, mild steel, and soft ferrite.

[0009] Preferably, the magnetic conductive sheet is fixed between the transmission mechanism and the permanent magnet.

[0010] Preferably, the transmission mechanism is a rotating shaft, and the magnetic conductive sheet is fixed between the rotating shaft and the permanent magnet.

[0011] Preferably, the transmission mechanism is a gear system, including a central driving gear and several gear sets with a transmission ratio of 16:1. The magnetic conductive sheet is fixed between the counting gear at the transmission end of each gear set and the permanent magnet.

[0012] Preferably, it further includes a rotor, and the rotor includes: a rotor support, which is fixedly connected to the central driving gear; a code disk, which is fixedly connected to the rotor support.

[0013] Preferably, the gear set includes a plastic gear and a magnetic conductive gear shaft.

[0014] Preferably, the material of the selected magnetic conductive gear shaft is one selected from nickel-iron magnetic conductive alloy, soft iron, high magnetic conductive alloy, mild steel, and soft ferrite.

[0015] Compared with the prior art, the advantages of the present utility model are that a magnetic conductive sheet is arranged between the transmission mechanism and the permanent magnet, which will not increase the size of the encoder. At the same time, it solves the problem that the economical and practical magnetoelectric encoder is relatively sensitive to external magnetic interference and is prone to errors, enabling the magnetic encoder to adapt to the working environment with electromagnetic interference, and having the characteristics of high detection accuracy and compact structure. Description of the Drawings

[0016] Figure 1 is an exploded view of the overall structure of an anti-magnetic interference encoder according to an embodiment of the present utility model.

[0017] Figure 2 is an exploded view of the magnetic wheel structure of an anti-magnetic interference encoder according to an embodiment of the present utility model.

[0018] Figure 3 is an exploded view of the overall structure of an anti-magnetic interference encoder according to another embodiment of the present utility model.

[0019] Figure 4 is an exploded view of the magnetic wheel structure of an anti-magnetic interference encoder according to another embodiment of the present utility model.

[0020] Figure 5 is an exploded view of a partial structure of an anti-magnetic interference encoder according to another embodiment of the present utility model

[0021] Description of the Reference Numerals:

[0022] 1. Housing, 10. Cover plate, 11. Outer cover, 2. Reading head, 20. PCB board, 21. Magnetic induction chip, 3. Magnetic wheel disc, 30. Transmission mechanism, 301. Plastic gear train, 3011. Counting gear, 302. Gear shaft, 303. Central drive gear, 31. Permanent magnet, 32. Magnetic conduction sheet, 4. Rotor, 40. Rotor support, 41. Code disc. Detailed implementation mode

[0023] The following further elaborates on the present utility model in conjunction with the accompanying drawings.

[0024] An encoder with anti-magnetic interference disclosed by the present utility model includes a housing 1, a reading head 2, and a magnetic wheel disc 3.

[0025] Referring to Figures 1 - 2 , in another embodiment of the present utility model, the housing 1 includes a cover plate 10 and an outer cover 11, the reading head 2 includes a PCB board 20 and a magnetic induction chip 21, and the magnetic wheel disc 3 includes a transmission mechanism 30, a permanent magnet 31, and a magnetic conduction sheet 32.

[0026] Among them, the transmission mechanism 30 is a rotating shaft, the magnetic conduction sheet 32 is located between the rotating shaft and the permanent magnet 31, and the three are fixed by glue. The PCB board 20 is fixed to the outer cover 11 by glue and screws. The permanent magnet 31 and the magnetic induction chip 21 fixed on the PCB board 20 are parallel and facing each other without contact. The cover plate 10 is arranged above the PCB board and is connected to the outer cover 11 by glue.

[0027] When the encoder works, the magnetic wheel disc 3 rotates to cause a magnetic field change, and the reading head 2 detects the magnetic field change, and realizes the counting of the encoder through the magnetoelectric principle. The magnetic conduction sheet 32 is made of a high magnetic conductivity alloy material, which can enhance the magnetic field input to the magnetic induction chip and prevent its distortion, and reduce the angular error caused by external magnetic interference.

[0028] Referring to Figures 3 - 5 , in an embodiment of the present utility model, the reading head 2 includes a PCB board 20 and a magnetic induction chip 21, the magnetic wheel disc 3 includes a transmission mechanism 30, a permanent magnet 31, and a magnetic conduction sheet 32, and the rotor 4 includes a rotor support 40 and a code disc 41.

[0029] Among them, the transmission mechanism 30 includes a plastic gear train 301, a gear shaft 302, and a central drive gear 303. The plastic gear train 301 and the gear shaft 302 are connected by a hole-shaft fit, and the gear shaft 302 and the housing 1 are connected by an interference fit. The plastic gear train 301 includes a three-stage reduction gear set with a transmission ratio of 16:1. The counting gears 3011 at the transmission end of each stage of the reduction gear set are sequentially fixed to the magnetic conductive sheet 32 and the permanent magnet 31 with glue. The central drive gear 303 meshes with the transmission start end of the first-stage reduction gear set of the plastic gear train 301. The central drive gear 303 is fixedly connected to the rotor carrier 40, and the rotor carrier 40 and the code disk 41 are fixedly connected with glue. The PCB board 20 is fixedly connected to the housing 1 in parallel and facing the code disk 41 without contact. The permanent magnet 31 assembled on the counting gear 3011 and the magnetic induction chip 21 fixed on the PCB board 20 are parallel and facing each other without contact.

[0030] When the encoder works, when the rotor 4 rotates, it drives the magnetic wheel disc 3 to rotate, resulting in a magnetic field change. The reading head 2 detects the magnetic field change and realizes multi-turn counting of the encoder through the magnetoelectric principle. The gear shaft 301 and the magnetic conductive sheet 32 are made of high-permeability alloy materials, which can enhance the magnetic field input to the magnetic induction chip and prevent its distortion, reducing the angular error caused by external magnetic interference.

[0031] The above are all the preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. An encoder resistant to magnetic interference, comprising a housing, a reading head and a magnetic disk, characterized in that the reading head includes: a PCB board fixedly connected to the inside of the housing; a plurality of sensing elements disposed on the PCB board; the magnetic disk includes: a transmission mechanism parallel and facing the PCB board; a plurality of permanent magnets fixedly connected to the transmission mechanism; a plurality of magnetic conductive sheets fixedly connected to the permanent magnets; the number of the sensing elements, the permanent magnets and the magnetic conductive sheets is equal.

2. The magnetoresistive encoder according to claim 1, wherein The sensing element is one of a magnetic induction chip, a Hall effect sensor, and a magnetoresistive sensor.

3. The magnetoresistive encoder according to claim 1, characterized in that, The housing includes a cover plate and an outer cover.

4. A magnetic interference resistant encoder according to claim 1, wherein, The material of the magnetic conductive sheet is selected from one of permalloy, soft iron, high magnetic permeability alloy, mild steel, and soft ferrite.

5. A magnetic interference resistant encoder according to claim 1, characterized in that, The magnetic conductive sheet is fixed between the transmission mechanism and the permanent magnet.

6. The magnetoresistive encoder according to claim 5, wherein, The transmission mechanism is a rotating shaft, and the magnetic conductive sheet is fixed between the rotating shaft and the permanent magnet.

7. An encoder with anti-magnetic interference according to claim 5, characterized in that, The transmission mechanism is a gear system, including a central driving gear and a plurality of gear sets with a transmission ratio of 16:

1. The magnetic conductive sheet is fixed between the counting gear at the end of each stage of the gear set transmission and the permanent magnet.

8. A magnetic interference resistant encoder according to claim 7, characterized in that, It further includes a rotor, and the rotor includes: a rotor support fixedly connected to the central driving gear; a code disk fixedly connected to the rotor support.

9. The magnetic interference resistant encoder according to claim 7, wherein, The gear set includes a plastic gear and a magnetic conductive gear shaft.

10. A magnetic interference resistant encoder according to claim 9, characterized in that, The material of the selected magnetic conductive gear shaft is selected from one of permalloy, soft iron, high magnetic permeability alloy, mild steel, and soft ferrite.

Images