Servo motor assembly structure and assembly method of servo motor

Abstract

The present invention relates to a servo motor assembly structure and an assembly method of a servo motor in the technical field of servo motors, including a housing, a stator assembly, a permanent magnet rotor assembly, and a servo coding assembly. The permanent magnet rotor assembly is rotatably arranged at the center of the stator assembly, and the servo coding assembly is arranged at one end of the permanent magnet rotor assembly. The permanent magnet rotor assembly includes a rotating shaft and a magnetic steel sleeve. The magnetic steel sleeve is a hollow structure, and the magnetic steel sleeve is sleeved in the middle of the rotating shaft. The rotating shaft can be inductively rotated with the stator assembly through the magnetic steel sleeve. The servo coding assembly includes a rotary encoder and a universal coupling. One end of the rotating shaft is movably connected to the rotary encoder through the universal coupling to provide a rotatable fulcrum that can axially offset when the rotating shaft axially swings. When axial swinging occurs, the offset rotation axis is corrected through a cross-connecting sleeve. The rotary encoder can rotate in the same axial direction, ensuring the accuracy of the speed, torque, and position control of the servo motor.

Description

Technical Field

[0001] The present invention relates to the technical field of servo motors, and particularly to a servo motor assembly structure and an assembly method of a servo motor. Background Art

[0002] A servo motor is a general term for a motor used in a servo mechanism. Detection components such as an optical encoder or a resolver, which are position or speed feedback elements, are usually applied to a servo motor for precise position detection. It is precisely because a servo motor is controlled by a feedback signal, which is different from a stepper motor controlled by an input pulse signal.

[0003] According to the Chinese invention patent with the existing publication number CN111585400B, a servo motor and its assembly method are described. For the servo motor under this structure, the installation position of the brake is changed from the rear to the front, increasing the distance from the detection component, thereby effectively reducing the signal interference between the brake and the detection component, and improving the accuracy of servo motor speed, torque, and position control. However, the connection method between the rotating shaft of the servo motor and the detection component, namely the rotary encoder, is a direct rigid connection. When the rotating shaft of the servo motor undergoes axial oscillation, the shaft deflects along the axial direction, resulting in signal interference between the detection components, which is not conducive to improving the accuracy of servo motor speed, torque, and position control. Summary of the Invention

[0004] The purpose of the present invention is to solve the above defects, and provide a servo motor assembly structure and an assembly method of a servo motor.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A servo motor assembly structure includes a housing, a stator assembly, a permanent magnet rotor assembly, and a servo coding assembly. The permanent magnet rotor assembly is rotatably arranged at the center of the stator assembly. The servo coding assembly is arranged at one end of the permanent magnet rotor assembly. The permanent magnet rotor assembly includes a rotating shaft and a magnetic steel sleeve. The magnetic steel sleeve is a hollow structure, and the magnetic steel sleeve is sleeved on the middle part of the rotating shaft. The rotating shaft can rotate mutually with the stator assembly through the magnetic steel sleeve. The servo coding assembly includes a rotary encoder and a universal coupling. One end of the rotating shaft is movably connected to the rotary encoder through the universal coupling.

[0007] In the above description, as a further solution, the universal coupling is composed of a first steering knuckle, a second steering knuckle, and a cross-connecting sleeve. Rotatable connecting pins are provided on both sides of the cross-connecting sleeve. The axial directions of the two connecting pins are perpendicular to each other. The two ends of the first steering knuckle and the second steering knuckle are respectively fixedly connected to the ends of one of the connecting pins. The middle parts of the first steering knuckle and the second steering knuckle are both connecting jacks. One end of the rotating shaft is inserted and fixed into the connecting jack of the first steering knuckle. A connecting cylinder is provided in the connecting jack of the second steering knuckle. One end of the connecting cylinder is inserted and fixed inside the connecting jack. The other end of the connecting cylinder extends to the center of the rotary encoder and is inserted and fixed to the rotary encoder;

[0008] By rotating the first steering knuckle and the second steering knuckle respectively along the axial directions of the connecting pins, the first steering knuckle and the second steering knuckle can rotate along the axial direction of the cross-connecting sleeve respectively, providing a rotatable fulcrum for axial offset when the rotating shaft swings axially.

[0009] In the above description, as a further solution, the stator assembly includes a stator core, a PCB board body, and a nylon cover. The stator core has a cylindrical hollow structure and is made of stator silicon steel. A number of groups of coils are wound on the surface of the stator core. The coils are electrically connected to the PCB board body. The nylon cover is a hollow structure and covers the rear end of the stator core. The stator core is fixedly connected inside the machine shell;

[0010] The stator core made of stator silicon steel can increase the magnetic force generated by the coils in the stator core. At the same time, the PCB board body supplies power to a number of groups of coils in turn, enabling the permanent magnet rotor assembly to rotate precisely according to the energization frequency of the PCB board body.

[0011] In the above description, as a further solution, a front end cover is provided on the front end face of the machine shell, and a rear end cover is provided on the rear end face of the machine shell. Both the front end cover and the rear end cover are hollow structures. The two ends of the rotating shaft are respectively inserted into the middle parts of the front end cover and the rear end cover. The two ends of the rotating shaft are rotatably connected to the middle parts of the front end cover and the rear end cover through bearings respectively. An oil seal gasket is further provided on the front end face of the front end cover. The oil seal gasket is an annular hollow structure and is sleeved on one end of the rotating shaft close to the front end cover and is embedded in the front end face of the front end cover.

[0012] In the above description, as a further solution, a corrugated spring sheet is provided between the bearing on one side of the front end cover and the front end cover. The corrugated spring sheet is a hollow structure, and the edge of the corrugated spring sheet is in a wavy structure. The corrugated spring sheet is sleeved on one end of the rotating shaft close to the front end cover and is clamped between the front edge of the bearing and the front end cover;

[0013] Axial runout refers to the inevitable slight movement of the rotating shaft of the servo motor along the axis direction during operation. It is clamped between the front edge of the bearing and the front end cover by a wave-shaped wave spring, making the matching interval between the rotor shaft and the rotor adjustable and compact, effectively preventing axial runout of the rotating shaft during operation.

[0014] In the above description, as a further solution, an encoder end cover is provided on the back of the rear end cover. The inside of the encoder end cover is a servo cavity for placing a rotary encoder. The universal coupling and the rotary encoder are rotatably arranged inside the servo cavity. One end of the rotating shaft away from the front end cover passes through the middle of the rear end cover and extends into the inside of the servo cavity, and is connected to the universal coupling.

[0015] An assembly method of a servo motor is assembled according to the above-mentioned structure of a servo motor assembly. The assembly steps include:

[0016] Step 1, stator assembly: Wind a number of energized coil groups on the surface of the stator core composed of stator silicon steel, weld the number of energized coil groups to the poles on the PCB board body, and at the same time sleeve a nylon cover on the rear end of the stator core. Then place the stator core, PCB board body and nylon cover as a whole inside the machine shell for fixed connection to obtain a stator assembly.

[0017] Step 2, rotor assembly: Sleeve a magnetic steel sleeve on the middle of the rotating shaft, and fix the magnetic steel sleeve on the middle of the rotating shaft by hot sleeving to obtain a permanent magnet rotor assembly.

[0018] Step 3, combined assembly of stator and rotor: Insert the permanent magnet rotor assembly obtained in Step 2 into the stator assembly obtained in Step 1, and respectively encapsulate the front end cover and the rear end cover at the front and rear ends of the machine shell, and extend the two ends of the rotating shaft rotatably out of the front end cover and the rear end cover respectively to obtain a motor group.

[0019] Step 4, servo component assembly: Rotatably connect the rotary encoder in the servo cavity of the encoder end cover, and movably connect one end of the rotating shaft close to the rear end cover to the rotary encoder through a universal coupling. Then cover the encoder end cover on the back of the rear end cover to complete the assembly of the servo motor.

[0020] In the above description, as a further solution, bearings can be sleeved between the end parts of the rotating shaft and the front end cover and the rear end cover respectively, and a wave spring is sleeved between the front end cover and the bearing.

[0021] The beneficial effects produced by the present invention are as follows:

[0022] A servo motor assembly structure of the present application enables the rotating shaft to rotate interactively with the stator assembly through a magnetic steel sleeve. The servo coding assembly includes a rotary encoder and a universal coupling. One end of the rotating shaft is movably connected to the rotary encoder through the universal coupling. The first steering knuckle and the second steering knuckle rotate respectively along the axial direction of the connecting pin, so that the first steering knuckle and the second steering knuckle can rotate respectively along the axial direction of the cross connecting sleeve, providing a rotating fulcrum that can axially offset when the rotating shaft undergoes axial swing. When axial swing occurs, the offset rotation axis is corrected through the cross connecting sleeve, and the rotary encoder can still rotate in the same axial direction, ensuring the accuracy of servo motor speed, torque, and position control. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a three-dimensional structure schematic diagram of a servo motor assembly structure according to the present invention;

[0024] Figure 2 is a structure schematic diagram of a permanent magnet rotor assembly in a servo motor assembly structure according to the present invention;

[0025] Figure 3 is an exploded structure schematic diagram of a permanent magnet rotor assembly in a servo motor assembly structure according to the present invention;

[0026] Figure 4 is a structure schematic diagram of a stator assembly in a servo motor assembly structure according to the present invention;

[0027] Figure 5 is an exploded structure schematic diagram of a stator assembly in a servo motor assembly structure according to the present invention;

[0028] Figure 6 is an exploded structure schematic diagram of a universal coupling in a servo motor assembly structure according to the present invention;

[0029] In the figure: 1 - housing, 2 - encoder end cover, 201 - servo cavity, 3 - rotating shaft, 4 - rotary encoder, 5 - PCB board, 6 - nylon cover, 7 - stator core, 8 - front end cover, 9 - oil seal washer, 10 - wave washer, 11 - bearing, 12 - magnetic steel sleeve, 13 - rear end cover, 14 - universal coupling, 1401 - first steering knuckle, 1402 - second steering knuckle, 1403 - cross connecting sleeve, 1404 - connecting pin, 1405 - connecting cylinder, 1406 - connecting jack. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] For the convenience of understanding by those skilled in the art, the present invention will be further described below in conjunction with embodiments and the accompanying drawings. The content mentioned in the embodiments does not limit the present invention. The present invention will be described in detail below with reference to the accompanying drawings.

[0031] Please refer to Figure 1-6 , which specifically implements a servo motor assembly structure and an assembly method of a servo motor, including a housing 1, a stator assembly, a permanent magnet rotor assembly, and a servo coding assembly. The permanent magnet rotor assembly is rotatably arranged at the center of the stator assembly, and the servo coding assembly is arranged at one end of the permanent magnet rotor assembly. The permanent magnet rotor assembly includes a rotating shaft 3 and a magnetic steel sleeve 12. The magnetic steel sleeve 12 is a hollow structure, and the magnetic steel sleeve 12 is sleeved in the middle of the rotating shaft 3. The rotating shaft 3 can rotate mutually with the stator assembly through the magnetic steel sleeve 12. The servo coding assembly includes a rotary encoder 4 and a universal coupling 14. One end of the rotating shaft 3 is movably connected to the rotary encoder 4 through the universal coupling 14.

[0032] The universal coupling 14 is composed of a first knuckle 1401, a second knuckle 1402, and a cross connecting sleeve 1403. Rotatable connecting pins 1404 are arranged on both sides of the cross connecting sleeve 1403. The axial directions of the two connecting pins 1404 are perpendicular to each other. The two ends of the first knuckle 1401 and the second knuckle 1402 are respectively fixedly connected to the ends of one of the connecting pins 1404. The middle parts of the first knuckle 1401 and the second knuckle 1402 are both connecting jacks 1406. The connecting jack 1406 of the first knuckle 1401 is inserted and fixed to one end of the rotating shaft 3. A connecting cylinder 1405 is arranged in the connecting jack 1406 of the second knuckle 1402. One end of the connecting cylinder 1405 is inserted and fixed to the inside of the connecting jack 1406, and the other end of the connecting cylinder 1405 extends to the center of the rotary encoder 4, and the connecting cylinder 1405 is inserted and fixed to the rotary encoder 4;

[0033] By rotating the first knuckle 1401 and the second knuckle 1402 respectively along the axial direction of the connecting pin 1404, the first knuckle 1401 and the second knuckle 1402 can rotate respectively along the axial direction of the cross connecting sleeve 1403, providing a rotatable fulcrum for axial offset when the rotating shaft 3 swings axially.

[0034] The stator assembly includes a stator core 7, a PCB board body 5, and a nylon cover 6. The stator core 7 has a cylindrical hollow structure and is made of stator silicon steel. Several groups of coils are wound on the surface of the stator core 7, and the coils are electrically connected to the PCB board body 5. The nylon cover 6 is a hollow structure, and the nylon cover 6 covers the rear end of the stator core 7. The stator core 7 is fixedly connected inside the housing 1;

[0035] The stator core 7 made of stator silicon steel can improve the magnetic force generated by the coils in the stator core 7. At the same time, the PCB board body 5 supplies power to several groups of coils in turn, so that the permanent magnet rotor assembly can rotate precisely according to the power-on frequency of the PCB board body 5.

[0036] The front end face of the housing 1 is provided with a front end cover 8, and the rear end face of the housing 1 is provided with a rear end cover 13. Both the front end cover 8 and the rear end cover 13 are of a hollow structure. The two ends of the rotating shaft 3 are respectively inserted into the middle parts of the front end cover 8 and the rear end cover 13. The two ends of the rotating shaft 3 are rotatably connected to the middle parts of the front end cover 8 and the rear end cover 13 through bearings 11 respectively. The front end face of the front end cover 8 is further provided with an oil seal gasket 9. The oil seal gasket 9 is of an annular hollow structure. The oil seal gasket 9 is sleeved on one end of the rotating shaft 3 close to the front end cover 8 and is embedded in the front end face of the front end cover 8.

[0037] A corrugated spring piece 10 is provided between the bearing 11 on one side of the front end cover 8 and the front end cover 8. The corrugated spring piece 10 is of a hollow structure. The edge of the corrugated spring piece 10 is of a wavy structure. The corrugated spring piece 10 is sleeved on one end of the rotating shaft 3 close to the front end cover 8, and the corrugated spring piece 10 is clamped between the front edge of the bearing 11 and the front end cover 8;

[0038] Axial runout refers to the inevitable slight movement of the rotating shaft 3 of the servo motor along the axial direction during operation. By clamping the corrugated spring piece with a wavy structure between the front edge of the bearing 11 and the front end cover 8, the matching interval between the rotor shaft and the rotor can be adjusted to be compact, effectively preventing the rotating shaft 3 from experiencing axial runout during operation.

[0039] The back of the rear end cover 13 is provided with an encoder end cover 2. The inside of the encoder end cover 2 is a servo cavity 201 for placing a rotary encoder 4. The universal coupling 14 and the rotary encoder 4 are both rotatably arranged inside the servo cavity 201. One end of the rotating shaft 3 far from the front end cover 8 passes through the middle part of the rear end cover 13 and extends into the inside of the servo cavity 201 and is connected to the universal coupling 14.

[0040] An assembly method of a servo motor, the assembly steps include:

[0041] Step 1, stator assembly. Wind a number of energized coil groups on the surface of the stator core 7 composed of stator silicon steel, weld the number of energized coil groups to the poles on the PCB board body 5, and at the same time sleeve a nylon cover 6 on the rear end of the stator core 7. Then place the stator core 7, the PCB board body 5 and the nylon cover 6 as a whole inside the housing 1 for fixed connection to obtain a stator assembly;

[0042] Step 2, rotor assembly. Sleeve a magnetic steel sleeve 12 on the middle part of the rotating shaft 3 and fix the magnetic steel sleeve 12 on the middle part of the rotating shaft 3 by means of hot fitting to obtain a permanent magnet rotor assembly;

[0043] Step 3: Assembly of the stator and the rotor. Insert the permanent magnet rotor assembly obtained in Step 2 into the stator assembly obtained in Step 1. Then, respectively encapsulate the front end cover 8 and the rear end cover 13 at the front and rear ends of the housing 1. The two ends of the rotating shaft 3 are respectively rotatably extended out of the front end cover 8 and the rear end cover 13. Bearings 11 can be sleeved between the end parts of the rotating shaft 3 and the front end cover 8 and the rear end cover 13 respectively. And the wave washer 10 is sleeved between the front end cover 8 and the bearing 11 to obtain the motor set.

[0044] Step 4: Assembly of the servo component. Rotatably connect the rotary encoder 4 in the servo cavity 201 of the encoder end cover 2, and movably connect one end of the rotating shaft 3 close to the rear end cover 13 with the rotary encoder 4 through the universal coupling 14. Then, cover the encoder end cover 2 on the back of the rear end cover 13 to complete the assembly of the servo motor.

[0045] The above is only a preferred embodiment of the present invention, and it is not intended to limit the present invention in any form. Although the present invention is disclosed above with the preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, when making some changes or modifications using the above-disclosed technical content into equivalent embodiments of equivalent changes, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical means of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. A servo motor assembly structure, comprising a housing, a stator assembly, a permanent magnet rotor assembly, and a servo coding assembly. The permanent magnet rotor assembly is rotatably disposed at the center of the stator assembly, and the servo coding assembly is disposed at one end of the permanent magnet rotor assembly. It is characterized in that: The permanent magnet rotor assembly includes a rotating shaft and a magnetic steel sleeve. The magnetic steel sleeve is of a hollow structure and is sleeved on the middle part of the rotating shaft. The rotating shaft can rotate mutually inductively with the stator assembly through the magnetic steel sleeve. The servo coding assembly includes a rotary encoder and a universal coupling. One end of the rotating shaft is movably connected to the rotary encoder through the universal coupling. The universal coupling consists of a first steering knuckle, a second steering knuckle and a cross connecting sleeve. Rotatable connecting pins are provided on both sides of the cross connecting sleeve. The axial directions of the two connecting pins are perpendicular to each other. The two ends of the first steering knuckle and the second steering knuckle are respectively fixedly connected to the ends of one of the connecting pins. The middle parts of the first steering knuckle and the second steering knuckle are both connecting jacks. The connecting jack of the first steering knuckle is inserted and fixed to one end of the rotating shaft. A connecting cylinder is provided in the connecting jack of the second steering knuckle. One end of the connecting cylinder is inserted and fixed to the inside of the connecting jack. The other end of the connecting cylinder extends to the center of the rotary encoder and is inserted and fixed to the rotary encoder.

2. The servo motor assembly structure according to claim 1, characterized in that: The stator assembly includes a stator core, a PCB board body and a nylon cover. The stator core has a cylindrical hollow structure and is made of stator silicon steel. A number of groups of coils are wound on the surface of the stator core. The coils are electrically connected to the PCB board body. The nylon cover is of a hollow structure and covers the rear end of the stator core. The stator core is fixedly connected inside the machine shell.

3. The servo motor assembly structure according to claim 1, characterized in that: A front end cover is provided on the front end face of the machine shell, and a rear end cover is provided on the rear end face of the machine shell. Both the front end cover and the rear end cover are of hollow structures. The two ends of the rotating shaft are respectively inserted into the middle parts of the front end cover and the rear end cover. The two ends of the rotating shaft are rotatably connected to the middle parts of the front end cover and the rear end cover through bearings respectively. An oil seal washer is further provided on the front end face of the front end cover. The oil seal washer is of an annular hollow structure and is sleeved on one end of the rotating shaft close to the front end cover and is embedded in the front end face of the front end cover.

4. The servo motor assembly structure according to claim 3, characterized in that: A corrugated spring sheet is provided between the bearing on the side close to the front end cover and the front end cover. The corrugated spring sheet is of a hollow structure. The edge of the corrugated spring sheet is of a wavy structure. The corrugated spring sheet is sleeved on one end of the rotating shaft close to the front end cover and is clamped between the front edge of the bearing and the front end cover.

5. The servo motor assembly structure according to claim 3, characterized in that: An encoder end cover is provided on the back of the rear end cover. The inside of the encoder end cover is a servo cavity for placing the rotary encoder. The universal coupling and the rotary encoder are both rotatably arranged inside the servo cavity. One end of the rotating shaft far from the front end cover passes through the middle part of the rear end cover and extends into the inside of the servo cavity and is connected to the universal coupling.

6. An assembly method for a servo motor, characterized in that: Assemble according to the servo motor assembly structure described in any one of claims 1 to 5. The assembly steps include: Step 1, stator assembly. Wind a number of energized coil groups on the surface of the stator core made of stator silicon steel, weld the number of energized coil groups to the poles on the PCB board body, and at the same time sleeve the nylon cover on the rear end part of the stator core. Then place the stator core, the PCB board body and the nylon cover as a whole inside the machine shell for fixed connection to obtain the stator assembly. Step 2, rotor assembly: sleeved a magnetic steel sleeve on the middle part of the rotating shaft, and fixed the magnetic steel sleeve on the middle part of the rotating shaft by hot sleeve method to obtain a permanent magnet rotor assembly; Step 3, stator and rotor combined assembly: insert the permanent magnet rotor assembly obtained in Step 2 into the stator assembly obtained in Step 1, respectively package the front end cover and the rear end cover at the front and rear ends of the machine shell, and the two ends of the rotating shaft extend out of the front end cover and the rear end cover rotatably respectively to obtain a motor set; Step 4, servo component assembly: rotatably connect a rotary encoder in the servo cavity of the encoder end cover, and movably connect one end of the rotating shaft close to the rear end cover with the rotary encoder through a universal coupling, and then cover the encoder end cover on the back of the rear end cover to complete the assembly of the servo motor.

7. The assembly method for a servo motor according to claim 6, characterized in that: In the Step 3, bearings can be sleeved between the end parts of the rotating shaft and the front end cover and the rear end cover respectively, and a corrugated spring sheet is sleeved between the front end cover and the bearing.

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