Novel absolute value magnetic encoder with magnetism isolating cover

Abstract

The utility model relates to the technical field of magnetic encoders, in particular to a novel absolute value magnetic encoder with a magnetism isolating cover, which comprises a rotating shaft, and the end part of the rotating shaft is provided with a bearing sleeving part capable of being sleeved with an inner ring of a bearing and a shaft support sleeving part capable of being sleeved with a shaft support; an outer ring of the bearing is fixed through a rear end cover, a magnetism isolating cover is arranged on the outer side of the rear end cover, and the magnetism isolating cover and the rear end cover are connected to form a shaft support moving cavity allowing the shaft support to move. The surface of the shaft support is provided with a PCB embedding groove for embedding an encoder PCB and a permanent magnet embedding groove for embedding two permanent magnets; the encoder PCB comprises a magnetic resistance sensor facing one side of the PCB embedding groove and a PCB plug connector facing one side of the magnetism isolating cover, and correspondingly, the magnetism isolating cover is provided with a plug connector through hole through which a plug cable can penetrate. The absolute value magnetic encoder with the magnetism isolating cover is simple in structure and convenient to operate, and the production efficiency can be greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of magnetic encoders, in particular to a novel absolute value magnetic encoder with a magnetic isolation cover. Background Art

[0002] Magnetic encoder is a detection device based on magnetic sensitive elements, generally composed of magnetic resistance and Hall elements. It outputs direction and position information by measuring the changes in the angle and displacement of the periodic magnetic field caused by the rotation of the motor. Magnetic encoders are widely used because of their high ease of use, high speed, good shock resistance, easy installation and maintenance, and low cost.

[0003] The Chinese utility model patent with publication number CN207884451U discloses a magnetic encoder installation structure for a motor. The magnetic encoder has many components, a complex structure, and a large volume. It is not suitable for use on a servo motor in terms of cost and maintainability.

[0004] The Chinese utility model patent with publication number CN211877055U discloses a magnetic encoder, which uses a magnetic shielding element made of soft steel containing 3.0 weight percent carbon, which can effectively reduce external magnetic interference. The encoder also includes a permanent magnet and a magnetic sensor. The permanent magnet has alternating N poles and S poles along the circumferential direction. As the rotating body of the rotating part rotates, the magnetic sensor detects the change in the magnetic field of the permanent magnet to obtain the direction and displacement offset of the rotating body, but it is expensive and difficult to manufacture.

[0005] The Chinese invention patent with publication number CN112781626A discloses a magnetic encoder, which has a central magnet, an absolute magnetoresistance sensor, a circuit substrate and a main gear plate distributed on a unified axis. The circuit substrate is slotted to place a back magnet, and a gear sensor is attached to the magnet. The absolute magnetoresistance sensor detects the central magnet and the gear sensor detects the main gear plate, and the combined processing of the two output data effectively improves the measurement accuracy of the encoder. However, the device has a complex structure and is difficult to miniaturize.

[0006] Therefore, a new technical solution is urgently needed to solve the above technical problems. Utility Model Content

[0007] The purpose of the utility model is to overcome the above-mentioned problems of the prior art and to provide a novel absolute magnetic encoder with a magnetic shield to solve the technical problems of the existing magnetic encoders, such as complex structure, large size, high cost and difficulty in assembly.

[0008] The above objectives are achieved through the following technical solutions:

[0009] A novel absolute value magnetic encoder with a magnetic shield, comprising a rotating shaft, the end of which is provided with a bearing sleeve portion capable of being sleeved by the inner ring of a bearing, and a shaft support sleeve portion capable of being sleeved by a shaft support; the outer ring of the bearing is fixed by a rear end cover, the outer side of the rear end cover is provided with a magnetic shield, and the magnetic shield and the rear end cover are connected to form a shaft support activity cavity capable of allowing the shaft support to move;

[0010] The surface of the shaft support is provided with a PCB embedding groove for embedding an encoder PCB board, and a permanent magnet embedding groove for embedding two permanent magnets; the encoder PCB board includes a magnetoresistive sensor on the side facing the PCB embedding groove, and a PCB connector on the side facing the magnetic shield, and correspondingly, a connector through hole for the plug-in cable to pass through is provided on the magnetic shield.

[0011] Furthermore, the rear end cover includes a bearing installation groove opened at the axial center position, and the bearing is installed in the bearing installation groove.

[0012] Furthermore, a bearing retaining ring capable of limiting the bearing is provided on one side of the bearing installation groove, and the other side of the bearing installation groove is limited by a bearing pressing plate.

[0013] Furthermore, a pressing plate embedding groove corresponding to the bearing pressing plate is provided on the rear end cover, and a pressing plate through hole through which the shaft support sleeve portion can pass is provided at the axial center position of the bearing pressing plate.

[0014] Furthermore, the PCB embedding groove is arranged at the axial center position of the shaft support, the two permanent magnet embedding grooves are arranged symmetrically about the PCB embedding groove axis, and the magnetoresistive sensor corresponds to the axial center position of the PCB embedding groove.

[0015] Furthermore, the permanent magnets are arranged in parallel with each other in the two permanent magnet slots.

[0016] Furthermore, a shaft support sleeve capable of sleeve-engaging the shaft support sleeve portion is provided at the axial center position on the other side of the shaft support.

[0017] Furthermore, the magnetic shield is circular, and includes a magnetic shield mounting bracket arranged on the outer wall. Correspondingly, a magnetic shield connecting hole is opened on the rear end cover, and the magnetic shield mounting bracket is connected to the magnetic shield connecting hole by screws.

[0018] Furthermore, a PCB board fixing column with a screw hole is provided on the inner wall of the magnetic shield, and correspondingly, a PCB board screw hole for screws to pass through is provided on the encoder PCB board, and the screw is screwed to the PCB board fixing column after passing through the PCB board screw hole.

[0019] Furthermore, a PCB board positioning column is provided on the inner wall of the magnetic shield, and correspondingly, a PCB board positioning hole corresponding to the PCB board positioning column is provided on the encoder PCB.

[0020] The utility model provides a new absolute magnetic encoder with a magnetic shield, which forms a closed magnetic shield space for installing the shaft support, permanent magnet and encoder PCB board through the rear end cover and the magnetic shield, ensuring the strength and integrity of the magnetic field. The magnetoresistive sensor is located in the middle of the magnetic field, and has better anti-interference performance and more stable resolution. Under the same magnetic field strength, this solution reduces the amount of permanent magnets required, which can effectively save the encoder cost; the magnetic shield enables the encoder to still operate stably in harsh environments, greatly improving the reliability of the encoder. In addition, the absolute magnetic encoder with a magnetic shield provided by the solution is not only simple in structure, simple to install and easy to operate, but also can greatly improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic structural diagram of a novel absolute magnetic encoder with a magnetic shield according to the utility model from a first viewing angle;

[0022] Figure 2 This is a second perspective structural schematic diagram of a novel absolute magnetic encoder with a magnetic shield according to the utility model;

[0023] Figure 3 This is an exploded view from the first perspective of a novel absolute magnetic encoder with a magnetic shield described in the utility model;

[0024] Figure 4 This is an exploded view from a second perspective of a novel absolute magnetic encoder with a magnetic shield described in the utility model.

[0025] Graphic marking:

[0026] 1-rotating shaft, 101-bearing sleeve connecting portion, 102-shaft support sleeve connecting portion;

[0027] 2-Bearing;

[0028] 3-shaft support, 301-PCB embedding groove, 302-permanent magnet embedding groove, 303-shaft sleeve, 304-fastening screw hole;

[0029] 4-rear end cover, 401-bearing mounting groove, 402-bearing retaining ring, 403-pressing sheet embedding groove, 404-magnetic shield connection hole;

[0030] 5-magnetic shield, 501-connector through hole, 502-magnetic shield mounting bracket, 503-PCB board fixing column, 504-PCB board positioning column;

[0031] 6-encoder PCB board, 601-magnetoresistive sensor, 602-PCB connector, 603-PCB board positioning hole, 604-PCB board screw hole;

[0032] 7-bearing pressing sheet, 701-pressing sheet through hole;

[0033] 8- Permanent magnet. DETAILED DESCRIPTION

[0034] The utility model is further described in detail below based on the accompanying drawings and embodiments. The described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0035] like Figure 1 to Figure 4 As shown, a novel absolute value magnetic encoder with a magnetic shield comprises a rotating shaft 1, the end of the rotating shaft 1 is provided with a bearing sleeve portion 101 capable of being sleeved with the inner ring of a bearing 2, and a shaft support sleeve portion 102 capable of being sleeved with a shaft support 3; the outer ring of the bearing 2 is fixed by a rear end cover 4, and a magnetic shield 5 is provided on the outer side of the rear end cover 4, and the magnetic shield 5 is connected to the rear end cover 4 to form a shaft support activity cavity capable of allowing the shaft support 3 to move;

[0036] The surface of the shaft support 3 is provided with a PCB embedding groove 301 for embedding the encoder PCB board 6, and a permanent magnet embedding groove 302 for embedding two permanent magnets 8; the encoder PCB board 6 includes a magnetoresistive sensor 601 facing the side of the PCB embedding groove 301, and a PCB connector 602 facing the side of the magnetic shield 5, and correspondingly, a connector through hole 501 for a plug-in cable to pass through is provided on the magnetic shield 5, and the external plug-in cable is electrically connected to the PCB connector 602 via the connector through hole 501.

[0037] It should be noted that the encoder PCB board 6 in this embodiment is a general circuit board in this field, which carries the circuit and chip of the entire encoder, and integrates the functions of signal acquisition, position compensation and conversion, and position output, and outputs the position information of the shaft to the outside through the cable connected by the PCB connector 602. In addition, the magnetic shield 5 and the shaft support 3 are made of magnetic shielding materials, such as copper, aluminum, ferrite, neodymium iron boron, silver and amorphous alloys.

[0038] like Figure 3 and Figure 4 As shown, the rear end cover 4 includes a bearing installation groove 401 opened at the axial center position, the bearing 2 is installed in the bearing installation groove 401, and the rotating shaft 2 passes through the bearing installation groove 401 to achieve sleeve connection with the inner ring of the bearing 2.

[0039] A bearing retaining ring 402 capable of limiting the position of the bearing 2 is disposed on one side of the bearing installation groove 401. In this embodiment, the bearing retaining ring 402 is integrally formed with the rear end cover 4, and the other side of the bearing installation groove 401 is limited by a bearing pressing sheet 7. This structure can firmly limit the bearing 2 in the bearing installation groove 401, and can also effectively prevent external interference with the bearing 2.

[0040] A pressing plate embedding groove 403 corresponding to the bearing pressing plate 7 is opened on the rear end cover 4, and the bearing pressing plate 7 is fixed by screws after being fitted with the pressing plate embedding groove 403; a pressing plate through hole 701 for the shaft support sleeve 102 to pass through is opened at the axial position of the bearing pressing plate 7, so as to facilitate the sleeve connection between the shaft support 2 and the shaft support sleeve 102.

[0041] It should be noted that, in this embodiment, the inner diameter of the bearing retaining ring 402 is smaller than the outer diameter of the bearing 2 , and the inner diameter of the pressing sheet through hole 701 is smaller than the outer diameter of the bearing 2 .

[0042] In this embodiment, the PCB embedding groove 301 is arranged at the axial center position of the shaft support 3, the two permanent magnet embedding grooves 302 are arranged symmetrically with respect to the PCB embedding groove 301, and the magnetoresistive sensor 601 corresponds to the axial center position of the PCB embedding groove 301. This structure can ensure that the magnetoresistive sensor 601 can accurately correspond to the end of the rotating shaft 1, and thus can accurately monitor its rotation.

[0043] Specifically, when the shaft rotates 1 turn, the uniform magnetic field also starts to rotate, and the magnetoresistive sensor 601 outputs sine and cosine signals according to the change in the direction of the magnetic field. Axial or radial movement will inevitably occur during the operation of the motor, and this movement is equivalent to the displacement of the magnetoresistive sensor 601 in the uniform magnetic field. Compared with the traditional circular single permanent magnet method, the advantage of this solution is that the displacement in the uniform magnetic field has less impact on the magnetoresistive sensor, and the feedback accuracy of the encoder and the smoothness of the motor operation are improved.

[0044] The permanent magnets 8 described in this embodiment are arranged parallel to each other in the two permanent magnet slots 302. It should be noted that the permanent magnets 8 described in this embodiment include an N pole and an S pole, which are installed parallel to the permanent magnet slots 302, and the corresponding surfaces have different poles, which can form a uniform magnetic field in conjunction with the movable cavity of the shaft support.

[0045] Specifically, the centers of the two square permanent magnets 8 are in a straight line with the centers of the rotating shaft 1 and the magnetoresistive sensor 601, so that a uniform magnetic field parallel to the surface of the shaft support 3 from the N pole to the S pole can be generated between the two permanent magnets 8.

[0046] like Figure 3 As shown, a shaft support sleeve 303 capable of sleeve-fitting the shaft support sleeve portion 102 is provided at the axial center position of the other side of the shaft support 3. This structure can realize the quick sleeve-fitting of the shaft support 3 with the shaft support sleeve portion 102 of the rotating shaft 1. In order to increase the firmness after connection, a fastening screw hole 304 can also be opened on the side wall of the shaft sleeve sleeve 303. By screwing the fastening screw, the shaft support 3 can be firmly connected to the rotating shaft 1. This structure allows the rotating shaft 1 and the shaft support 3 to rotate together without any displacement, which is crucial for high-precision rotary motion because it ensures that the rotation angle of the rotating shaft and the feedback angle of the encoder will not deviate.

[0047] like Figure 3 and Figure 4 As shown, the magnetic shield 5 in this embodiment is circular, and includes a magnetic shield mounting bracket 502 arranged on the outer wall. Correspondingly, a magnetic shield connecting hole 404 is opened on the rear end cover 4, and the magnetic shield mounting bracket 502 is connected to the magnetic shield connecting hole 404 by screws.

[0048] As a connection method between the magnetic shield 5 and the encoder PCB board 6 in this embodiment, a PCB board fixing column 503 with a screw hole is opened on the inner wall of the magnetic shield 5, and correspondingly, a PCB board screw hole 604 for the screw to pass through is opened on the encoder PCB board 6, and the screw passes through the PCB board screw hole 604 and is screwed to the PCB board fixing column 503.

[0049] In addition, a PCB board positioning column 504 is opened on the inner wall of the magnetic shield 5, and correspondingly, a PCB board positioning hole 603 corresponding to the PCB board positioning column 504 is opened on the encoder PCB board 6. By positioning the PCB board positioning column 504 with the PCB board positioning hole 603, the PCB board screw hole 604 and the PCB board fixing column 503 can be quickly positioned, thereby achieving quick connection.

[0050] Specifically, this design significantly improves the stability of the internal magnetic field, and neither the leakage magnetic field of the motor itself nor the external magnetic field can have any impact on the uniform magnetic field of the permanent magnet. Therefore, regardless of the harsh environmental conditions, this solution can still maintain stable and reliable operation.

[0051] The above description is only for illustrating the implementation mode of the present invention and is not intended to limit the present invention. For those skilled in the art, any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A new type of absolute magnetic encoder with magnetic shield, characterized in that: The invention comprises a rotating shaft (1), wherein the end of the rotating shaft (1) is provided with a bearing sleeve portion (101) capable of being sleeved with the inner ring of a bearing (2), and a shaft support sleeve portion (102) capable of being sleeved with a shaft support (3); the outer ring of the bearing (2) is fixed by a rear end cover (4), and a magnetic shield (5) is provided on the outer side of the rear end cover (4); the magnetic shield (5) is connected to the rear end cover (4) to form a shaft support activity cavity capable of allowing the shaft support (3) to move; The surface of the shaft support (3) is provided with a PCB embedding groove (301) in which an encoder PCB board (6) can be embedded, and a permanent magnet embedding groove (302) in which two permanent magnets (8) can be embedded; the encoder PCB board (6) comprises a magnetoresistive sensor (601) on a side facing the PCB embedding groove (301), and a PCB connector (602) on a side facing the magnetic shield (5); correspondingly, a connector through hole (501) is provided on the magnetic shield (5) in which a plug-in cable can pass through.

2. The novel absolute magnetic encoder with magnetic shield according to claim 1 is characterized in that: The rear end cover (4) comprises a bearing installation groove (401) opened at the axis center position, and the bearing (2) is installed in the bearing installation groove (401).

3. The novel absolute magnetic encoder with magnetic shield according to claim 2 is characterized in that: A bearing retaining ring (402) capable of limiting the position of the bearing (2) is provided on one side of the bearing installation groove (401), and the other side of the bearing installation groove (401) is limited by a bearing pressing plate (7).

4. The novel absolute magnetic encoder with magnetic shield according to claim 3 is characterized in that: The rear end cover (4) is provided with a pressing plate embedding groove (403) corresponding to the bearing pressing plate (7).

5. The novel absolute magnetic encoder with magnetic shield according to claim 1 is characterized in that: The PCB embedding groove (301) is arranged at the axial center position of the shaft support (3), the two permanent magnet embedding grooves (302) are arranged symmetrically with respect to the PCB embedding groove (301), and the magnetoresistive sensor (601) corresponds to the axial center position of the PCB embedding groove (301).

6. The novel absolute magnetic encoder with magnetic shield according to claim 5 is characterized in that: The permanent magnets (8) are arranged in parallel with each other in the two permanent magnet embedding grooves (302).

7. A novel absolute magnetic encoder with a magnetic shield according to claim 1 or 5, characterized in that: A shaft support sleeve (303) capable of sleeve-engaging the shaft support sleeve portion (102) is provided at the axial center position of the other side of the shaft support (3).

8. The novel absolute value magnetic encoder with magnetic shield according to claim 1 is characterized in that: The magnetic shield (5) is circular, and includes a magnetic shield mounting bracket (502) arranged on the outer wall. Correspondingly, a magnetic shield connecting hole (404) is opened on the rear end cover (4), and the magnetic shield mounting bracket (502) is connected to the magnetic shield connecting hole (404) by screws.

9. A novel absolute magnetic encoder with a magnetic shield according to claim 1 or 8, characterized in that: A PCB board fixing column (503) with a screw hole is provided on the inner wall of the magnetic shield (5), and correspondingly, a PCB board screw hole (604) for a screw to pass through is provided on the encoder PCB board (6), and the screw is screwed to the PCB board fixing column (503) after passing through the PCB board screw hole (604).

10. The novel absolute value magnetic encoder with magnetic shield according to claim 9 is characterized in that: A PCB board positioning column (504) is provided on the inner wall of the magnetic shield (5), and correspondingly, a PCB board positioning hole (603) corresponding to the PCB board positioning column (504) is provided on the encoder PCB board (6).

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