High-precision servo electric cylinder

Abstract

The high-precision servo electric cylinder comprises a cylinder barrel, an encoder assembly, a piston rod, a motor assembly, a harmonic speed reducer and a ball screw, the motor assembly, the harmonic speed reducer and the ball screw are sequentially arranged in the cylinder barrel from back to front, a rigid gear of the harmonic speed reducer is connected with the motor assembly, and a flexible gear of the harmonic speed reducer is connected with a speed reducer output flange. The speed reducer output flange is connected with the ball screw rod, the motor assembly is arranged at the rear end of the cylinder barrel and connected with the encoder assembly, the interior of the piston rod is hollow, and the rear end of the piston rod extends into the cylinder barrel and is connected with the ball screw nut. The utility model provides a high-precision servo electric cylinder, and aims to solve the problem of insufficient precision in the existing six-degree-of-freedom motion platform technology.

Description

Technical Field

[0001] The utility model relates to the technical field of servo electric cylinders, and more specifically, to a high-precision servo electric cylinder. Background Art

[0002] As the application scope of servo electric cylinders becomes wider and wider, especially in six-degree-of-freedom motion platforms, the accuracy cannot meet certain application scenarios, such as optics, optoelectronics and other fields, where the accuracy requirements need to reach the micron level.

[0003] In order to make the six-degree-of-freedom motion platform applicable to the high-precision field, the conditions can only be met by improving the accuracy of the actuator, that is, the servo electric cylinder. At present, the accuracy of the six-degree-of-freedom motion platform on the market can only reach the 0.01mm level, and cannot reach the micron level. Only when the accuracy reaches the micron level can it be considered to have entered the threshold of the high-precision field and can be used in some scenarios in the high-precision field. Utility Model Content

[0004] The utility model aims to provide a high-precision servo electric cylinder to solve the problem of insufficient precision in the existing six-degree-of-freedom motion platform technology.

[0005] The utility model solves the above-mentioned technical problems with the following technical solutions: a high-precision servo electric cylinder, comprising a cylinder, an encoder assembly, a motor assembly, a harmonic reducer, a piston rod and a ball screw, wherein the motor assembly is connected to the rear end of the cylinder and to the encoder assembly, the ball screw is arranged in the cylinder, the rigid wheel of the harmonic reducer is connected to the motor assembly, and its flexible wheel is connected to the reducer output flange, and the reducer output flange is connected to the ball screw screw, the piston rod is hollow inside, and its rear end extends into the cylinder and is connected to the ball screw nut.

[0006] Preferably, in the high-precision servo electric cylinder, the motor assembly includes a frameless torque motor, a casing and a motor shaft, the casing is connected to the rear end of the cylinder barrel, the frameless torque motor is arranged in the casing, the motor shaft passes through the rotor of the frameless torque motor and is connected to it, the front end of the motor shaft is transmission-connected to the reducer assembly, and the rear end thereof is connected to the encoder assembly.

[0007] Preferably, in the high-precision servo electric cylinder, a sleeve is coaxially provided on the inner wall of the cylinder barrel, the ball screw nut is arranged in the sleeve, and the piston rod extends into the sleeve and slides in contact with the inner wall thereof.

[0008] Preferably, the high-precision servo electric cylinder further includes a front buffer pad and a rear buffer pad, the front buffer pad is arranged at the front end of the sleeve, and the rear buffer pad is arranged at the front end of the reducer output flange.

[0009] Preferably, the high-precision servo electric cylinder further includes a front hinge fork and a rear hinge fork, wherein the front hinge fork is connected to the front end of the piston rod, the rear hinge fork is arranged on the rear side of the cylinder barrel and connected to the cylinder barrel through a connecting assembly, and the encoder assembly is arranged on the rear hinge fork.

[0010] Preferably, in the high-precision servo electric cylinder, the connecting assembly includes a plurality of pull rods, and two ends of the pull rods are respectively connected to the housing and the rear hinge.

[0011] Preferably, in the high-precision servo electric cylinder, the encoder assembly includes an encoder and an encoder cover, the encoder cover is connected to the rear hinge, and the encoder is arranged in the encoder cover and connected to the motor shaft.

[0012] The beneficial effects of the utility model are:

[0013] The high-precision servo electric cylinder of the utility model fixes the rigid wheel of the harmonic reducer, and when the wave generator is driven to operate continuously by the frameless torque motor and the motor shaft, the flexible wheel of the harmonic reducer is forced to continuously deform, so that the gears of the harmonic reducer continuously change their working state during the process of meshing, engaging, meshing, and disengaging, thereby generating staggered tooth motion and realizing the motion transmission between the wave generator and the flexible wheel. Moreover, the transmission accuracy of the harmonic reducer is less than 1.5 arc min, the side clearance is very small, and even side clearance-free transmission can be realized, so the transmission accuracy of the electric cylinder can be significantly improved.

[0014] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is an exploded view of the high-precision servo electric cylinder described in the utility model;

[0016] Figure 2 It is a cross-sectional view of the high-precision servo electric cylinder described in the utility model.

[0017] In the accompanying drawings, the components represented by the reference numerals and their related functional parts are listed as follows:

[0018] 1. Rear hinge; 2. Encoder cover; 3. Pull rod; 4. Encoder; 5. Motor rear cover; 6. Motor housing; 7. Motor shaft; 8. Frameless torque motor; 9. Locking nut; 10. Motor end cover; 11. Harmonic reducer; 12. Screw block; 13. Reducer output flange; 14. Lower buffer pad; 15. Flat key; 16. Ball screw; 17. Front cover guide ring; 18. Front cover; 19. Cylinder; 20. Dust ring; 21. Sleeve guide ring; 22. Sleeve; 23. Ball screw nut; 24. Upper buffer pad; 25. Piston rod; 26. Front hinge. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0020] It should be noted that, in the description of the present invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0021] Figure 1-Figure 2 A high-precision servo electric cylinder provided for an embodiment of the utility model includes a cylinder 19, an encoder assembly, a motor assembly, a harmonic reducer 11, a piston rod 25 and a ball screw 16, wherein the motor assembly is connected to the rear end of the cylinder 19 and to the encoder assembly, the ball screw 16 is arranged in the cylinder 19, the rigid wheel of the harmonic reducer 11 is connected to the motor assembly, and its flexible wheel is connected to the reducer output flange 13, and the reducer output flange 13 is connected to the ball screw screw, the piston rod 25 is hollow inside, and its rear end extends into the cylinder 19 and is connected to the ball screw nut 23.

[0022] In this embodiment, the rigid wheel of the harmonic reducer 11 is connected to the motor assembly, and its flexible wheel is connected to the ball screw through the reducer output flange 13. When the motor assembly is working, it drives the rigid wheel of the harmonic reducer 11 to rotate, and the flexible wheel of the harmonic reducer 11 drives the reducer output flange 13 and the ball screw to rotate. At this time, the rigid wheel of the harmonic reducer 11 rotates continuously, and the flexible wheel of the harmonic reducer 11 is continuously deformed, so that the gears of the harmonic reducer 11 continuously change their working states during the process of meshing, engaging, meshing, and disengaging, thereby generating staggered tooth motion and realizing the motion transmission between the wave generator and the flexible wheel, thereby driving the reducer output flange 13 to rotate, and the ball screw also rotates accordingly. At this time, the ball screw nut 23 makes a linear motion along its axial direction in the cylinder 19, and drives the piston rod 25 to move together, so that the piston rod 25 makes a linear motion along its axial direction relative to the cylinder 19, and retracts relative to the cylinder 19.

[0023] As a specific connection structure between the ball screw 16 and the reducer output flange 13, such as Figure 1-Figure 2 As shown in , the ball screw is a stepped shaft type and has a threaded hole at the rear end. The shaft head at the rear end of the ball screw extends into the reducer output flange 13, and its shaft shoulder contacts the front end of the reducer output flange 13. Then, a screw pressing block 12 is provided at the rear end of the reducer output flange 13. The screw pressing block 12 is connected to the shaft head of the ball screw 16 through screws, and contacts the ball screw 16 and the reducer output flange 13 at the same time. At the same time, a plurality of flat keys 15 are arranged between the ball screw and the reducer output flange 13, and the torque is transmitted through the flat keys 15 to ensure that the ball screw is driven to rotate synchronously when the reducer output flange 13 rotates.

[0024] A front end cover 18 may be provided at the front end of the cylinder barrel 19, and the piston rod 25 passes through the front end cover 18. A front end cover guide ring 17 is provided inside the front end cover 18, and the front end cover guide ring 17 is slidably connected with the piston rod 25, and the movement of the piston rod 25 is guided by the front end cover guide ring 17. At the same time, a dust ring 20 is also provided inside the front end cover 18 to prevent dust from being brought into the cylinder barrel 19 during the movement of the piston rod 25.

[0025] Preferably, as another embodiment of the utility model, the motor assembly includes a frameless torque motor 8, a casing and a motor shaft 7, the casing is connected to the rear end of the cylinder 19, the frameless torque motor 8 is arranged in the casing, the motor shaft 7 passes through the rotor of the frameless torque motor 8 and is connected thereto, the front end of the motor shaft 7 is transmission-connected to the reducer assembly, and the rear end thereof is connected to the encoder assembly.

[0026] In this embodiment, the housing includes a motor rear cover 5, a motor housing 6 and a motor end cover 10, the front end of the motor housing 6 is connected to the rear end of the cylinder 19 through the motor end cover 10, and the rear end is connected to the motor end cover 10, the stator of the frameless torque motor 8 is coaxially fixed in the motor housing 6, the motor shaft 7 coaxially penetrates the rotor of the frameless torque motor 8 and is connected thereto, and at the same time, the front and rear ends of the motor shaft 7 also penetrate the motor end cover 10 and the motor rear cover 5 respectively, and are respectively connected to the reducer assembly and the encoder assembly. When the frameless torque motor 8 is working, it drives the motor shaft 7 to rotate, and the motor shaft 7 drives the reducer assembly and the encoder assembly to rotate synchronously.

[0027] As a specific structure of the motor shaft 7, Figure 1-Figure 2 As shown in , a thread is provided on the front half and a shoulder is provided on the rear half. The rear end of the rotor of the frameless torque motor 8 contacts the shoulder. A locking nut 9 is threadedly connected to the rear half of the motor shaft 7. The locking nut 9 is tightened until it contacts the front end of the rotor of the frameless torque motor 8, so that the rotor of the frameless torque motor 8 can be fixed on the motor shaft 7.

[0028] In addition, a first stop corresponding to the stop of the rigid wheel of the harmonic reducer 11 is provided on the casing, which is used for installation and positioning with the stop of the rigid wheel of the harmonic reducer 11; a second stop corresponding to the stop of the flexible wheel of the harmonic reducer 11 is provided on the reducer output flange 13, which is used for installation and positioning with the stop of the flexible wheel of the harmonic reducer 11.

[0029] Preferably, as another embodiment of the utility model, a sleeve 22 is coaxially provided on the inner wall of the cylinder 19, the ball screw nut 23 is arranged in the sleeve 22, and the piston rod 25 extends into the sleeve 22 and slides in contact with the inner wall thereof.

[0030] In this embodiment, a sleeve 22 is coaxially provided in the cylinder 19 , and the movement trajectory of the piston rod 25 is limited by the sleeve 22 , thereby ensuring the stability of the piston rod 25 during operation.

[0031] As a specific structure of the cylinder 19, Figure 1-Figure 2 As shown in FIG. 1 , two sleeve guide rings 21 are arranged at intervals inside the cylinder 19 , and the movement of the piston rod 25 is guided by the sleeve guide rings 21 .

[0032] Preferably, as another embodiment of the utility model, it further comprises a front buffer pad and a rear buffer pad, wherein the front buffer pad is arranged at the front end of the sleeve 22 , and the rear buffer pad is arranged at the front end of the reducer output flange 13 .

[0033] In this embodiment, the front buffer pad is used to effectively avoid the rigid collision between the sleeve 22 and the ball screw nut 23 and the reducer output flange 13; the rear buffer pad is used to effectively avoid the rigid collision between the sleeve 22 and the front end cover 18.

[0034] Preferably, as another embodiment of the utility model, it also includes a front hinge 26 and a rear hinge 1, the front hinge 26 is connected to the front end of the piston rod 25, the rear hinge 1 is arranged on the rear side of the cylinder 19, and is connected to the cylinder 19 through a connecting assembly, and the encoder assembly is arranged on the rear hinge 1.

[0035] In this embodiment, the connection between the servo electric cylinder and the external components can be achieved through the front hinge 26 and the rear hinge 1.

[0036] Preferably, as another embodiment of the present invention, the connecting assembly includes a plurality of pull rods 3, and two ends of the pull rods 3 are respectively connected to the housing and the rear hinge 1.

[0037] Preferably, as another embodiment of the utility model, the encoder 4 component includes an encoder 4 and an encoder cover 2, the encoder cover 2 is connected to the rear hinge 1, and the encoder 4 is arranged in the encoder cover 2 and connected to the motor shaft 7.

[0038] Although the implementation scheme of the utility model has been disclosed as above, it is not limited to the applications listed in the specification and implementation scheme. It can be fully applied to various fields suitable for the utility model. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the utility model is not limited to the specific details and the embodiments shown and described herein.

Claims

1. A high-precision servo electric cylinder, characterized in that: It includes a cylinder, an encoder assembly, a motor assembly, a harmonic reducer, a piston rod and a ball screw. The motor assembly is connected to the rear end of the cylinder and to the encoder assembly. The ball screw is arranged in the cylinder. The rigid wheel of the harmonic reducer is connected to the motor assembly, and its flexible wheel is connected to the reducer output flange, and the reducer output flange is connected to the ball screw screw. The piston rod is hollow inside, and its rear end extends into the cylinder and is connected to the ball screw nut.

2. A high-precision servo electric cylinder as claimed in claim 1, characterized in that: The motor assembly includes a frameless torque motor, a casing and a motor shaft. The casing is connected to the rear end of the cylinder barrel, the frameless torque motor is arranged in the casing, the motor shaft passes through the rotor of the frameless torque motor and is connected to it, the front end of the motor shaft is transmission-connected to the reducer assembly, and the rear end thereof is connected to the encoder assembly.

3. A high-precision servo electric cylinder as claimed in claim 2, characterized in that: A sleeve is coaxially arranged on the inner wall of the cylinder, the ball screw nut is arranged in the sleeve, and the piston rod extends into the sleeve and slides in contact with the inner wall of the sleeve.

4. A high-precision servo electric cylinder as claimed in claim 3, characterized in that: It also includes a front buffer pad and a rear buffer pad, wherein the front buffer pad is arranged at the front end of the sleeve, and the rear buffer pad is arranged at the front end of the output flange of the reducer.

5. A high-precision servo electric cylinder as claimed in claim 2, characterized in that: It also includes a front hinge and a rear hinge, wherein the front hinge is connected to the front end of the piston rod, the rear hinge is arranged at the rear side of the cylinder barrel and connected to the cylinder barrel through a connecting component, and the encoder component is arranged on the rear hinge.

6. A high-precision servo electric cylinder as claimed in claim 5, characterized in that: The connecting assembly includes a plurality of pull rods, and two ends of the pull rods are respectively connected to the housing and the rear hinge.

7. A high-precision servo electric cylinder as claimed in claim 5, characterized in that: The encoder assembly includes an encoder and an encoder cover, wherein the encoder cover is connected to the rear hinge, and the encoder is arranged in the encoder cover and connected to the motor shaft.

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