Rotary table

Abstract

The utility model provides a rotary table which comprises a first stepping motor, a first harmonic reducer, a first encoder, a base and a support assembly. The first stepping motor is connected with the input end of the first harmonic reducer, the first harmonic reducer is fixed to the base, the first encoder is connected with a rotating shaft of the first stepping motor, and the first encoder is used for measuring the rotating angle of the first stepping motor. The support assembly comprises a vertically-arranged stand column, the stand column is provided with a speed reducer connecting end and a load connecting end, the speed reducer connecting end is connected with the output end of the first harmonic speed reducer, and the load connecting end is connected with a load. The rotating angle output by the stepping motor under subdivision control of the controller is subjected to high-magnification speed reduction through the harmonic reducer and then drives the load to rotate by the high-resolution precision angle, the high-precision control requirement can be met by the conventional precision encoder, the cost of the rotary table is effectively reduced, and the rotary table is high in reliability and easy to implement.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of precision automation equipment, and particularly relates to a rotary table. BACKGROUND

[0002] The rotary table is a kind of precision angle motion control equipment, which is widely applied in the fields of military industry, security and civil use. The traditional low-cost rotary table mostly adopts a stepping motor as a driving component. The stepping motor is directly connected with a load, receives a control signal and directly drives the load to rotate. The structure design and control logic are simple. However, the rotary table is limited by the low rotation angle precision of the stepping motor. Even if the control subdivision technology is adopted, the traditional rotary table is difficult to meet the high-precision requirement. At present, the high-precision rotary table adopts an electromagnetic motor to directly drive the load. This leads to the need of high-precision encoders and high-precision closed-loop control systems for realizing high-precision control, which greatly increases the production and use cost of the rotary table and limits the application and popularization of the rotary table in various industries. CONTENT OF THE UTILITY MODEL

[0003] To solve the above technical problems, the present application provides a rotary table, which comprises a first stepping motor, a first harmonic reducer, a first encoder, a base and a support assembly. The first stepping motor is arranged below the first harmonic reducer and is connected with an input shaft of the first harmonic reducer. The first harmonic reducer is fixed on the base, so that an output shaft thereof is vertically upward. The first encoder is connected with a rotating shaft of the first stepping motor. The first encoder is used for measuring the rotation angle of the first stepping motor. The support assembly comprises a vertical column arranged on the base. A lower end of the vertical column is a reducer connecting end, which is used for connecting with an output end of the first harmonic reducer. An upper end of the vertical column is a load connecting end, which is used for directly or indirectly connecting with a load.

[0004] The rotation angle output by the stepping motor under the subdivision control of the controller is high-resolution precision angle after high-multiplication deceleration of the harmonic reducer. Since the speed ratio of the harmonic reducer is stable during transmission and the precision is high, the encoder only needs to measure and control the rotation of the stepping motor, so as to realize the accurate control of the rotation angle of the load in the horizontal plane. The conventional precision encoder can meet the requirement of high-precision control.

[0005] As an improvement of the present application, the support assembly further comprises a second stepper motor, a second harmonic reducer, a second encoder and a support cantilever. The second stepper motor is arranged on the side of the second harmonic reducer away from the support cantilever and is connected with the input end of the second harmonic reducer. The second harmonic reducer is fixed to the load connecting end of the column. The output shaft of the second harmonic reducer is arranged horizontally. The second encoder is connected with the rotating shaft of the second stepper motor. The support cantilever is arranged horizontally. One end of the support cantilever is connected with the output end of the second harmonic reducer. The other end of the support cantilever is used for connecting the load.

[0006] When the second stepper motor rotates by a certain angle, the rotation of the support cantilever is driven by the second harmonic reducer at a smaller angle, and in turn drives the load to rotate around the central axis of the support cantilever, so as to accurately adjust the rotation angle of the load in the vertical direction. After the improvement, the load can be accurately adjusted in the horizontal and vertical directions under the driving of the first stepper motor and the second stepper motor.

[0007] As an improvement of the present application, the load connecting end is horizontally provided with a lower cross beam. The lower cross beam is provided at both ends with a first support part and a second support part extending upward. The first support part is horizontally provided with a hinge shaft used for connecting the load. The support assembly further comprises a second stepper motor, a second harmonic reducer and a second encoder. The second stepper motor is connected with the input end of the second harmonic reducer. The second harmonic reducer is fixed to the second support part. The output shaft of the second harmonic reducer is arranged horizontally. The second encoder is connected with the rotating shaft of the second stepper motor. The output end of the second harmonic reducer is used for connecting the side of the load opposite to the hinge shaft.

[0008] When the second stepper motor rotates by a certain angle, the rotation of the support cantilever is driven by the second harmonic reducer at a smaller angle, and in turn drives the load to rotate around the central axis of the support cantilever, so as to accurately adjust the rotation angle of the load in the vertical direction. This improvement changes the support of the load from one side to two sides, thereby improving the stress state of the load. After the improvement, the load can be accurately adjusted in the horizontal and vertical directions under the driving of the first stepper motor and the second stepper motor.

[0009] In some embodiments, the base is conical with a small upper part and a large lower part. A central hole is arranged in the middle of the base. A groove for mounting the first harmonic reducer is arranged in the upper part of the central hole.

[0010] In some embodiments, a first slewing bearing is arranged between the column and the base, an inner ring of the first slewing bearing is connected with the column, and an outer ring of the first slewing bearing is connected with the base. Part of the load generated by the load can be transmitted to the base through the column and the first slewing bearing, so as to reduce the load borne by the first harmonic reducer and improve the service life of the first harmonic reducer.

[0011] In some embodiments, a second slewing bearing is arranged between the support cantilever and the load connecting end of the column, an inner ring of the second slewing bearing is connected with the support cantilever, and an outer ring of the second slewing bearing is connected with the load connecting end. The second slewing bearing has the same effect as the first slewing bearing, i.e., part of the load generated by the load is borne by the second slewing bearing, so as to reduce the load borne by the second harmonic reducer and improve the service life of the second harmonic reducer.

[0012] In some embodiments, the turntable further comprises a leveling mechanism for adjusting the levelness of the base, the leveling mechanism comprising a leveling base, a leveling mounting plate, and at least three leveling screws. The leveling base is provided with positioning blind holes corresponding in number and position to the leveling screws, the leveling mounting plate is arranged in parallel with the leveling base, the leveling mounting plate is fixedly connected with the base, the leveling mounting plate is provided with positioning bolt holes corresponding to the positioning blind holes, the leveling screws are matched with the positioning bolt holes, and the leveling screws pass through the positioning bolt holes and are inserted into the positioning blind holes. By changing the amount of rotation of the adjusting screw, the distance and the included angle between the leveling mounting plate and the leveling base can be adjusted, so as to adjust the levelness of the base and facilitate zero calibration of the turntable.

[0013] Preferably, the leveling mechanism comprises three leveling screws.

[0014] In some embodiments, the leveling mechanism further comprises a level arranged on the leveling mounting plate, the level being used to identify the levelness of the leveling mounting plate and facilitate leveling calibration.

[0015] The base and the leveling mounting plate can be fixedly connected, such as by welding or one-piece forming, or can be detachably connected, such as by threaded connection. Preferably, the base and the leveling mounting plate are detachably connected, so that the leveling mechanism can be used or not used according to needs.

[0016] The beneficial effects of the present application: the present application adopts a specific combination of a stepper motor, a harmonic reducer and an angle encoder to drive a load, the rotation angle output by the stepper motor under the subdivision control of the controller is high-multiplication decelerated by the harmonic reducer, and then drives the load to rotate with high-resolution precision angle. Since the speed ratio of the harmonic reducer is stable during transmission, the precision is high, therefore the encoder only needs to measure and control the rotation of the stepper motor to realize accurate control of the rotation angle of the load. A conventional precision encoder can meet the needs of high-precision control, effectively reduce the cost of the turntable, and has high reliability and is easy to implement. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0018] Figure 1 is the front view of the first embodiment of the present application;

[0019] Figure 2 is the exploded perspective view of the first embodiment of the present application;

[0020] Figure 3 is the front view of the second embodiment of the present application;

[0021] Figure 4 is the front view of the third embodiment of the present application;

[0022] Figure 5 is the perspective view of the fourth embodiment of the present application;

[0023] Figure 6 is the perspective view of the leveling mechanism in the fourth embodiment of the present application. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other alternative embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0025] Figure 1 and Figure 2The first embodiment of the application is shown, including a base 1, a support assembly 2, a first stepper motor 3, a first harmonic reducer 4 and a first encoder 5. The base 1 is conical with a smaller upper part and a larger lower part, and has a central hole 11 in the middle, and a groove 12 for mounting the first harmonic reducer 4 is arranged on the upper part of the central hole 11. The first stepper motor 3 is a double-output-shaft stepper motor, one end of the rotating shaft of which is connected to the first encoder 5, and the other end is connected to the first harmonic reducer 4, which is fixed in the groove 12 on the base 1.

[0026] The support assembly 2 includes a vertical column 21, the lower end of which is a reducer connecting end 211 connected to the first harmonic reducer 4, and the upper end of which is a load connecting end 212 for connecting the load 10. The first stepper motor 3 can drive the column 21 to rotate in the horizontal plane through the first harmonic reducer 4, so as to adjust the rotation angle of the load 10 in the horizontal plane.

[0027] When the rotating shaft of the first stepper motor 3 rotates by an angle θ under the control of the pulse electric signal, the input shaft of the first harmonic reducer 4 is driven to rotate by the corresponding angle θ, and if the speed ratio of the first harmonic reducer 4 is i, then the rotation angle of the output shaft of the first harmonic reducer 4 is the rotation angle of the rotating shaft of the first stepper motor 3 divided by the speed ratio of the first harmonic reducer 4, i.e. α = iθ.

[0028] For example, the first stepper motor 3 is a 2-phase stepper motor, and the first stepper motor 3 outputs a step angle of 1.8° at a time under the control of the pulse electric signal. The first rotary encoder is a conventional precision encoder, which is matched with a 12-bit decoding circuit and has an angle resolution of 0.09°, which is higher than the precision of the rotation angle of the stepper motor, so that accurate measurement and control of the stepper motor can be realized. If the speed ratio of the first harmonic reducer 4 is 100, then when the first stepper motor 3 outputs a step angle of 1.8° at a time under the control of the pulse electric current, the rotation angle of the output shaft of the first harmonic reducer 4 is 0.018°, and the rotation angle of the load 10 in the horizontal plane is 0.018°, so that a conventional encoder can be used to accurately adjust the rotation angle of the load 10. If the controller subdivision technology is used, for example, the step angle of the stepper motor is 0.36°, and a conventional precision encoder can still satisfy the accurate control of the stepper motor. After the rotation angle generated by the stepper motor is reduced by the first harmonic reducer 4, the rotation angle precision of the load 10 can reach 0.0036°.

[0029] The rotary table provided by the application can be operated in an open-loop control mode or a closed-loop control mode. When high-speed continuous positioning is required, the rotary table is operated in the open-loop control mode, the main control unit continuously sends a position command to drive the first stepper motor 3 to operate according to the requirement, and the first encoder 5 continuously monitors the rotation angle of the rotating shaft of the first stepper motor 3 in the process, and continuously compares the rotation angle with the required positioning angle. When the control system determines that the error between the two is less than the design tolerance error, the control system does not send a step compensation command to the first stepper motor 3. When the control system determines that the error between the two is greater than the design tolerance error, a step compensation command is sent to the first stepper motor 3 to adjust the rotation angle of the rotating shaft of the first stepper motor 3, so that high-precision positioning is realized.

[0030] When low-speed continuous positioning is required, the rotary table can also be operated in the closed-loop control mode. After the first stepper motor 3 executes the positioning command sent by the control system, the first encoder 5 feeds back the rotation angle of the rotating shaft of the first stepper motor 3 to the system, and the closed-loop control system sends a correction command to the first stepper motor 3 according to the feedback information to control the first stepper motor 3 to correct the position, so that high-precision positioning is realized.

[0031] In the first embodiment, the first encoder 5 can be an optical encoder or a mechanical encoder.

[0032] In the second embodiment of the application, as shown in Figure 3 The second stepper motor 22 is connected with the second harmonic reducer 23, the second harmonic reducer 23 is fixed to the load connection end 212 of the column 21, and the second encoder 24 is connected with the rotating shaft of the second stepper motor 22. The support cantilever 25 is horizontally arranged, one end of the support cantilever 25 is connected with the second harmonic reducer 23, and the other end is connected with the load 10. The second stepper motor 22 can drive the support cantilever 25 to rotate around the central axis of the support cantilever 25 to adjust the rotation angle of the load 10 in the vertical direction through the second harmonic reducer 23, so as to realize accurate adjustment of the rotation angle of the load 10 in the vertical direction. In combination with the first embodiment, the rotation angles of the load 10 in the horizontal and vertical directions can be accurately adjusted at the same time.

[0033] In the second embodiment of the application, the second stepper motor 22 can also be different from the first embodiment, and a single-output shaft motor is adopted. The second encoder 24 is arranged between the second stepper motor 22 and the second harmonic reducer 23, and is sleeved on the rotating shaft of the second stepper motor 22. The rotating shaft of the second stepper motor 22 is connected with the input shaft of the second harmonic reducer 23.

[0034] In the second embodiment of the present application, the second harmonic reducer 23 or the second encoder 24 can be omitted as needed. For example, when the angle accuracy requirement of the load 10 in the vertical direction is not high, the second harmonic reducer 23 can be omitted, and the second stepping motor 22 is directly connected to the support cantilever 25, thereby reducing the equipment cost.

[0035] The third embodiment of the present application is an improvement on the second embodiment, as shown in Figure 4 The first rotary bearing 26 is arranged between the column 21 and the base 1, the inner ring of the first rotary bearing 26 is fixedly connected with the column 21, and the outer ring of the first rotary bearing 26 is fixedly connected with the base 1. The second rotary bearing 27 is arranged between the support cantilever 25 and the load connection end 212, the support cantilever 25 is connected with the inner ring of the second rotary bearing 27, and the load connection end 212 is connected with the outer ring of the second rotary bearing 27. Part of the load generated by the load 10 can be transmitted to the column 21 by the second rotary bearing 27, and then transmitted to the base 1 through the first rotary bearing 26, thereby reducing the load borne by the first harmonic reducer 4 and the second harmonic reducer 23 and improving the service life.

[0036] The fourth embodiment of the present application gives another improved way of the first embodiment, as shown in Figure 5 The lower cross beam 213 is horizontally arranged on the load connection end 212, the first support part 214 and the second support part 215 extending vertically upward are respectively arranged at both ends of the lower cross beam 213, and the hinge shaft 216 for connecting with the load 10 is horizontally arranged on the first support part 214.

[0037] The bracket assembly 2 further comprises the second stepping motor 22, the second harmonic reducer 23, and the second encoder 24, the second stepping motor 22 is connected with the second encoder 24, the second harmonic reducer 23 is fixed to the second support part 215, the input end of the second harmonic reducer 23 is connected with the rotating shaft of the second stepping motor 22, and the output end of the second harmonic reducer 23 is connected to the side of the load 10 opposite to the hinge shaft 216. The second stepping motor 22 can drive the load 10 to rotate in the vertical direction through the second harmonic reducer 23, so as to adjust the angle of the load 10 in the vertical direction. In combination with the first embodiment, the accurate adjustment of the angles of the load 10 in the horizontal and vertical directions can be realized. This improved way changes the one-side support of the load 10 to two-side support, thereby improving the stress state of the load 10.

[0038] In the fourth embodiment of the present application, as shown in Figure 5 and Figure 6As shown, the application also includes a leveling mechanism 6 for adjusting the levelness of the base 1. The leveling mechanism 6 includes a leveling base 61, a leveling mounting plate 62, and leveling screws 63. The leveling base 61 is provided with three positioning blind holes 611. The leveling mounting plate 62 is arranged in parallel with the leveling base 61 and is detachably connected to the base 1. The leveling mounting plate 62 is provided with positioning bolt holes 621 corresponding to the three positioning blind holes 611. The leveling screws 63 are matched with the positioning bolt holes 621 and pass through the positioning bolt holes 621 and are inserted into the positioning blind holes 611. By changing the screwing amount of the adjusting screws 63, the distance and the included angle between the leveling mounting plate 62 and the leveling base 61 can be adjusted, so that the levelness of the base 1 is adjusted, and the zero position calibration of the turntable is facilitated.

[0039] Further, the leveling mounting plate 62 can be provided with a level 64 for identifying the levelness of the leveling mounting plate 62, facilitating leveling calibration.

[0040] Finally, it should be noted that if the application embodiments involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement condition, etc. between the components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly.

[0041] In addition, if the application embodiments involve descriptions of "first", "second", etc., the descriptions of "first", "second", etc. are only for description purposes and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of a person skilled in the art, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist and is not within the protection scope of the application.

[0042] The above is only an embodiment of the application, and does not limit the patent scope of the application. Any equivalent structure or equivalent process transformation using the contents of the application specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the application.

Claims

1. A turntable, characterized by, The first step motor, the first harmonic reducer, the first encoder, the base and the support assembly are included. The first step motor is arranged below the first harmonic reducer and is connected with the input shaft of the first harmonic reducer, the first harmonic reducer is fixed on the base, the output shaft of the first harmonic reducer is vertically upward, the first encoder is connected with the rotating shaft of the first step motor, and the first encoder is used for measuring the rotating angle of the first step motor. The support assembly includes a vertical column arranged on the base, the lower end of the vertical column is a reducer connecting end used for connecting with the output end of the first harmonic reducer, and the upper end of the vertical column is a load connecting end.

2. The turntable of claim 1, wherein, The support assembly further includes a second step motor, a second harmonic reducer, a second encoder and a support cantilever. The second step motor is arranged on the side of the second harmonic reducer away from the support cantilever and is connected with the input end of the second harmonic reducer, the second harmonic reducer is fixed on the load connecting end of the vertical column, the output shaft of the second harmonic reducer is horizontally arranged, the second encoder is connected with the rotating shaft of the second step motor, the support cantilever is horizontally arranged, one end of the support cantilever is connected with the output end of the second harmonic reducer, and the other end is used for connecting a load.

3. The turntable of claim 1, wherein, A lower cross beam is horizontally arranged on the load connecting end, the two ends of the lower cross beam are respectively provided with a first support part and a second support part which are vertically upwardly extended, and a hinge shaft used for connecting a load is horizontally arranged on the first support part. The support assembly further includes a second step motor, a second harmonic reducer and a second encoder, the second step motor is connected with the input end of the second harmonic reducer, the second harmonic reducer is fixed on the second support part, the output shaft of the second harmonic reducer is horizontally arranged, the second encoder is connected with the rotating shaft of the second step motor, and the output end of the second harmonic reducer is used for connecting the side of the load opposite to the hinge shaft.

4. A turntable according to any one of claims 1 to 3, characterised in that, The base is conical and is provided with a central hole in the middle, and a groove used for mounting the first harmonic reducer is arranged on the upper portion of the central hole.

5. A turntable according to any one of claims 1 to 3, characterised in that A first rotary bearing is arranged between the vertical column and the base, the inner ring of the first rotary bearing is connected with the vertical column, and the outer ring of the first rotary bearing is connected with the base.

6. The turntable of claim 2, wherein, A second rotary bearing is arranged between the support cantilever and the load connecting end of the vertical column, the inner ring of the second rotary bearing is fixedly connected with the support cantilever, and the outer ring of the second rotary bearing is fixedly connected with the load connecting end.

7. The turntable of claim 4 wherein, The rotary table further includes a leveling mechanism used for adjusting the levelness of the base, the leveling mechanism includes a leveling base, a leveling mounting plate and at least three leveling screws. The leveling base is provided with positioning blind holes corresponding in number and position to the leveling screws, the leveling mounting plate is arranged in parallel with the leveling base, the leveling mounting plate is fixedly connected with the base, the leveling mounting plate is provided with positioning bolt holes corresponding to the positioning blind holes, the leveling screws are matched with the positioning bolt holes, and the leveling screws pass through the positioning bolt holes and are inserted into the positioning blind holes.

8. The turntable of claim 7, wherein, The leveling mechanism comprises three leveling screws.

9. The turntable of claim 7, wherein, The leveling mechanism further comprises a level arranged on the leveling mounting plate and used for identifying the levelness of the leveling mounting plate.

10. The turntable of claim 7, wherein, The base and the leveling mounting plate are detachably connected.

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