A high-precision fully closed-loop integrated electric cylinder

Abstract

The utility model relates to the technical field of electric cylinders, and discloses a high-precision fully closed-loop integrated electric cylinder, comprising a cylinder body, a screw rod rotating in the cylinder body, an output shaft moving linearly along the axial direction of the screw rod at the end of the cylinder body, and a limiting structure arranged between the output shaft and the screw rod, wherein the rotation of the screw rod is controlled by a motor, and a control structure for accurately controlling the movement of the output shaft is arranged between the cylinder body and the output shaft, wherein the control structure comprises a drive control module connected to a motor signal, a feedback structure for monitoring the actual displacement of the output shaft and feeding back to the drive control module, and an encoder for monitoring the actual rotation speed of the motor and feeding back to the drive control module, wherein the drive control module commands the motor to rotate according to the feedback structure to compensate for the telescopic stroke error of the output shaft, and commands the motor to rotate according to the feedback of the encoder to compensate for the telescopic speed error of the output shaft, wherein the electric cylinder reduces the error of the moving distance and speed of the output shaft through the cooperation among the feedback structure, the encoder and the drive control module, and ensures the running accuracy of the output shaft.

Description

Technical Field

[0001] The utility model relates to the technical field of electric cylinders, in particular to a high-precision fully closed-loop integrated electric cylinder. Background Art

[0002] The electric cylinder is a modular product that integrates the motor and the lead screw. It can convert the motor's rotational motion into linear motion and has the characteristics of precise speed and position control.

[0003] Chinese patent application number 201922010992.7 discloses a motor and an electric cylinder having the motor, including a mounting seat; a stator fixed in the mounting seat; a screw shaft rotatably mounted on the mounting seat and inserted into the stator, the screw shaft being used to cooperate with the screw thread of the slider; a bearing including a bearing inner ring and a bearing outer ring, the bearing inner ring being sleeved outside the screw shaft, and the bearing outer ring being mounted on the mounting seat; a rotor coaxially mounted on the screw shaft and located in the stator; an encoder mounted on one end of the screw shaft and located in the mounting seat; and a circuit board mounted in the mounting seat, the circuit board being electrically connected to the encoder.

[0004] The patent determines the target position of the slider by combining the number of motor revolutions fed back by the encoder and the lead of the screw. However, the encoder always feeds back the number of motor revolutions and the actual speed of the motor. When the lead accuracy of the screw is poor, or there is a large clearance between the screw hole of the slider and the screw, or there is slippage between the coupling, the screw and the motor shaft, there will be errors in the transmission accuracy of the slider, affecting the accuracy of the electric cylinder. Utility Model Content

[0005] The utility model aims to solve the problem that the movement precision of the electric cylinder in the prior art may have errors, and provides a high-precision full-closed-loop integrated electric cylinder.

[0006] In order to solve the above technical problems, the utility model is solved by the following technical solutions:

[0007] A high-precision fully closed-loop integrated electric cylinder comprises a cylinder body, a screw rod rotatably arranged in the cylinder body, an output shaft which moves back and forth linearly along the axial direction of the screw rod at the end of the cylinder body, and a limiting structure arranged between the output shaft and the screw rod for controlling the linear movement of the output shaft when the screw rod rotates. The rotation of the screw rod is controlled by a motor. A control structure for accurately controlling the moving distance and speed of the output shaft is arranged between the cylinder body and the output shaft. The control structure comprises a drive control module connected to the motor signal, a feedback structure arranged between the cylinder body and the output shaft for monitoring the actual displacement of the output shaft and feeding back to the drive control module, and an encoder arranged on the motor for monitoring the actual rotation speed of the motor and feeding back to the drive control module. The drive control module commands the motor to rotate according to the feedback structure to compensate for the telescopic stroke error of the output shaft caused by the output shaft moving distance error. The drive control module commands the motor to rotate according to the feedback of the encoder to compensate for the telescopic speed error of the output shaft caused by the motor rotation speed error.

[0008] With the above solution, the motor drives the screw to rotate, and the output shaft is controlled to move linearly through the limit structure. The feedback structure monitors the actual displacement value of the output shaft and feeds it back to the drive control module. The drive control module controls the motor to rotate to compensate for the error of the output shaft movement and ensure the accuracy of the final output shaft extension stroke. At the same time, the encoder monitors the actual speed of the motor and feeds it back to the drive control module. The drive control module adjusts the motor speed to compensate for the error of the output shaft extension speed, so that the output shaft movement speed in the electric cylinder is improved in accuracy. The feedback structure, encoder and drive control module are used to reduce the error of the output shaft extension stroke and speed, and ensure the operation accuracy of the output shaft.

[0009] Preferably, the feedback structure includes a grating scale fixed to the outside of the cylinder body and extending along the extension and retraction direction of the output shaft, an indicator fixed to the output shaft and corresponding to the scale on the grating scale as the output shaft retracts and retracts, and a grating cover arranged outside the cylinder body to block external light, and the grating scale is connected to the drive control module signal.

[0010] With the above solution, when the screw rotates, the output shaft moves linearly, driving the indicator to move; the actual displacement distance of the output shaft is monitored by the displacement value between the grating scale and the indicator, and is fed back to the drive control module through the grating scale, and then the motor is controlled to rotate to compensate for the error in the output shaft movement distance, and finally the required precise displacement is obtained. The grating cover blocks external light to ensure that the grating scale can read accurately.

[0011] Preferably, the limiting structure includes a mating component fixed to one end of the output shaft close to the screw and mating with the screw thread, and a guiding structure arranged between the mating component and the cylinder body to drive the mating component to move axially along the screw.

[0012] By adopting the above scheme, the matching component and the guide structure cooperate to convert the rotation of the screw rod into the linear movement of the output shaft.

[0013] Preferably, the mating component includes a nut mating with the screw rod and a connecting tube whose two ends are respectively fixed to the nut and the output shaft and through which the screw rod can be inserted.

[0014] Preferably, the guide structure comprises a guide block protruding from the outer ring wall of the connecting pipe and a guide groove provided on the cylinder body for the guide block to be inserted into and guide the guide block to move along the axial direction of the screw rod.

[0015] By adopting the above solution, after the guide block is inserted into the guide groove, the connection pipe and the nut are restricted from rotating, so that the nut, the connection pipe and the output shaft can only reciprocate linearly along the axial direction of the screw rod.

[0016] Preferably, a quick-install structure is provided between the guide block and the connecting pipe to facilitate the disassembly and assembly of the guide block.

[0017] With the above solution, the guide block and the guide groove cooperate to limit the rotation of the connecting tube and control the linear movement of the connecting tube. During long-term use, the guide block is prone to wear or deformation, resulting in a decrease in the precision of the grating scale and the indicator. Therefore, it needs to be replaced regularly. The quick-release structure facilitates the replacement of the guide block.

[0018] Preferably, the quick-install structure includes a slot recessed on the outer ring wall of the connecting tube, an insert block protruding from the guide block and insertable into and adapted to the slot, and a fixing structure arranged between the insert block and the slot.

[0019] By adopting the above solution, the insert block and the slot are adapted and then connected by a fixed structure, thereby avoiding relative movement between the guide block and the connecting pipe and ensuring that the guide block is fixedly installed on the connecting pipe.

[0020] Preferably, the fixing structure includes a through hole arranged on the guide block, a threaded hole arranged at the bottom of the slot, and a locking bolt, and the locking bolt is tightly fitted with the threaded hole after passing through the through hole.

[0021] By adopting the above solution, after the locking bolt passes through the through hole, it is tightly fitted with the threaded hole through thread engagement, ensuring that the guide block is fixedly installed on the connecting pipe.

[0022] The utility model has significant technical effects due to the adoption of the above technical solutions: by adding a grating ruler and an indicator, the actual displacement distance of the output shaft is monitored, and the feedback is given to the drive control module to control the motor rotation compensation error, and finally the required precise movement is obtained; at the same time, the encoder monitors the actual speed of the motor and feeds back to the drive control module, and the drive control module adjusts the motor speed to compensate for the error of the output shaft running speed, so that the moving speed of the output shaft in the electric cylinder is improved in accuracy. The error of the output shaft moving distance and speed is reduced by the cooperation between the feedback structure, the encoder and the drive control module, and the running accuracy of the output shaft is guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1It is an axonometric diagram of a high-precision fully closed-loop integrated electric cylinder in the embodiment;

[0024] Figure 2 This is a disassembled diagram of a high-precision fully closed-loop integrated electric cylinder in the embodiment;

[0025] Figure 3 yes Figure 2 A in the enlarged view;

[0026] Figure 4 This is a front view of a high-precision fully closed-loop integrated electric cylinder in an embodiment;

[0027] Figure 5 yes Figure 4 The cross-sectional view at BB in FIG.

[0028] Figure 6 yes Figure 5 Enlarged view of point C in the figure.

[0029] The names of the parts indicated by the numerical labels in the above drawings are as follows: 1. Cylinder body; 2. Screw rod; 3. Output shaft; 4. Motor; 5. Drive control module; 6. Encoder; 7. Grating scale; 8. Indicator; 9. Avoidance groove; 10. Grating cover; 11. Nut; 12. Connecting pipe; 13. Guide block; 14. Guide groove; 15. Slot; 16. Insert block; 17. Through hole; 18. Threaded hole; 19. Locking bolt; 20. Mounting block. DETAILED DESCRIPTION

[0030] The utility model is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0031] Example

[0032] A high-precision fully closed-loop integrated electric cylinder, refer to Figures 1 to 6 , including a cylinder body 1, a motor 4 is fixedly arranged on one side of the cylinder body 1, and the motor 4 is installed on one side of the cylinder body 1 through a front cover mounting plate, a screw rod 2 is rotatably arranged inside the cylinder body 1, and the rotation of the screw rod 2 is controlled by the motor 4. An output shaft 3 is arranged on the side of the cylinder body 1 away from the motor 4 to move linearly along the axial direction of the screw rod 2, and a limiting structure is arranged between the output shaft 3 and the screw rod 2 to control the linear movement of the output shaft 3 when the screw rod 2 rotates. The motor 4 drives the screw rod 2 to rotate, and the linear movement of the output shaft 3 is controlled by the limiting structure.

[0033] The limiting structure includes a matching component fixed to one end of the output shaft 3 close to the screw rod 2 and threadedly matched with the screw rod 2, and a guide structure is provided between the matching component and the cylinder body 1 to drive the matching component to move along the axial direction of the screw rod 2. The guide structure limits the rotation of the matching component, so that when the screw rod 2 rotates, the matching component and the guide structure cooperate to convert the rotation of the screw rod 2 into the linear movement of the output shaft 3.

[0034] The mating assembly includes a nut 11 mating with the screw 2 and a connecting tube 12 whose two ends are respectively fixed to the nut 11 and the output shaft 3 and through which the screw 2 can be inserted, and the guide structure includes a guide block 13 protruding from the outer ring wall of the connecting tube 12 and a guide groove 14 provided on the cylinder body 1 for the guide block 13 to be inserted and guide it to move along the axial direction of the screw 2. After the guide block 13 is inserted into the guide groove 14, the rotation of the connecting tube 12 and the nut 11 is restricted, so that the nut 11, the connecting tube 12 and the output shaft 3 can only reciprocate in a straight line along the axial direction of the screw 2. In this embodiment, the connecting tube 12 and the nut 11 are fixedly connected by a threaded structure.

[0035] In this embodiment, a ball screw motor is used to provide the screw 2 and the motor 4 mentioned in the above solution, and the nut 11 is a ball nut.

[0036] When the electric cylinder is running, when the lead accuracy of the screw rod 2 is poor, or there is a large fit clearance between the nut 11 and the screw rod 2, or there is slippage between the screw rod 2 and the motor shaft, there will be errors in the transmission accuracy of the output shaft 3. Therefore, a control structure is provided between the cylinder body 1 and the output shaft 3 to accurately control the moving distance and speed of the output shaft 3.

[0037] The control structure includes a drive control module 5 connected to the motor 4 signal, a feedback structure arranged between the cylinder body 1 and the output shaft 3, and an encoder 6 arranged on the motor 4. The feedback structure monitors the actual displacement value of the output shaft 3 and feeds back to the drive control module 5. The drive control module 5 controls the rotation of the motor 4 to compensate for the error of the movement of the output shaft 3 and ensure the precise displacement of the output shaft 3. At the same time, the encoder 6 monitors the actual speed of the motor 4 and feeds back to the drive control module 5. The drive control module 5 adjusts the speed of the motor 4 to compensate for the error of the running speed of the output shaft 3, so that the moving speed of the output shaft 3 in the electric cylinder is improved in accuracy. The error of the moving distance and speed of the output shaft 3 is reduced through the cooperation between the feedback structure, the encoder 6 and the drive control module 5, so as to ensure the running accuracy of the output shaft 3.

[0038] In this embodiment, the encoder 6 adopts a rotary encoder, and the encoder 6 is installed on the side of the motor 4 away from the cylinder body 1. An encoder rear cover is provided on the external cover of the encoder 6 to protect the encoder 6. The drive control module 5 is installed on the side of the encoder rear cover away from the motor 4, and is connected to the encoder rear cover through the drive control module bottom plate. A drive control module rear cover is provided on the external cover of the drive control module 5 to protect the drive control module 5. The drive control module rear cover is provided with an aviation plug connected to the drive control module 5. The drive control module 5 is placed inside the electric cylinder and connected to the external machine position through the aviation plug to realize point-to-point control.

[0039] The feedback structure includes a grating ruler 7 fixed on the outside of the cylinder body 1 and extending along the extension direction of the output shaft 3. The grating ruler 7 is connected to the drive control module 5 by signal. An indicator 8 is fixedly provided on the output shaft 3. The indicator 8 corresponds to the scale on the grating ruler 7 as the output shaft 3 is extended and retracted. A grating cover 10 is provided on the outside of the cylinder body 1 to block external light. In this embodiment, the indicator 8 is installed on the connecting pipe 12 through the mounting block 20, and the indicator 8 is a grating ruler strip. The cylinder body 1 is provided with an avoidance groove 9 for the mounting block 20 and the indicator 8 to pass through and move along the axial direction of the screw 2. When the screw 2 rotates, the nut 11 and the connecting pipe 12 move linearly to drive the indicator 8 to move; the actual displacement distance of the output shaft 3 is monitored by the displacement value between the grating ruler 7 and the indicator 8, and is fed back to the drive control module 5 through the grating ruler 7, and then the motor 4 is controlled to rotate to compensate for the error of the moving distance of the output shaft 3, and finally the required precise displacement is obtained.

[0040] The connection method between the grating ruler 7, motor 4, encoder 6 and drive control module 5 and the feedback control system are all existing technologies and will not be elaborated here. In addition, the coordination and working principle of the indicator 8 and the grating ruler 7 are also existing technologies and will not be elaborated here.

[0041] The output shaft 3, motor 4, encoder 6, grating ruler 7, indicator 8 and drive control module 5 of the electric cylinder are assembled together in sequence, which saves space and simplifies installation and wiring, and only power lines and communication lines are required.

[0042] The guide block 13 and the guide groove 14 cooperate to limit the rotation of the connecting tube 12 and control the linear movement of the connecting tube 12. During long-term use, the guide block 13 is prone to wear or deformation, resulting in a decrease in the precision of the cooperation between the grating scale 7 and the indicator 8. Therefore, it needs to be replaced regularly. A quick-release structure is provided between the guide block 13 and the connecting tube 12 to facilitate the replacement of the guide block 13.

[0043] The quick-install structure includes a slot 15 recessed on the outer ring wall of the connecting tube 12, an insert block 16 that can be inserted into the slot 15 is convexly provided on the guide block 13, the insert block 16 is adapted to the slot 15, and a fixing structure is provided between the insert block 16 and the slot 15. The insert block 16 is adapted to the slot 15, and then connected by the fixing structure, so as to avoid relative movement between the guide block 13 and the connecting tube 12, and ensure that the guide block 13 is fixedly installed on the connecting tube 12.

[0044] The fixing structure includes a through hole 17 arranged on the guide block 13, a threaded hole 18 is arranged at the bottom of the slot 15, and also includes a locking bolt 19. After the locking bolt 19 passes through the through hole 17, it is tightly fitted with the threaded hole 18 through thread engagement to ensure that the guide block 13 is fixedly installed on the connecting pipe 12.

[0045] The above is only a preferred embodiment of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A high-precision fully closed-loop integrated electric cylinder, comprising a cylinder body (1), a screw rod (2) rotatably arranged in the cylinder body (1), an output shaft (3) at the end of the cylinder body (1) which reciprocates linearly along the axial direction of the screw rod (2), and a limiting structure arranged between the output shaft (3) and the screw rod (2) for controlling the linear movement of the output shaft (3) when the screw rod (2) rotates, wherein the rotation of the screw rod (2) is controlled by a motor (4), and characterized in that: A control structure for accurately controlling the moving distance and speed of the output shaft (3) is arranged between the cylinder body (1) and the output shaft (3), the control structure comprising a drive control module (5) connected to a motor (4) signal, a feedback structure arranged between the cylinder body (1) and the output shaft (3) for monitoring the actual displacement of the output shaft (3) and feeding back to the drive control module (5), and an encoder (6) arranged on the motor (4) for monitoring the actual rotation speed of the motor (4) and feeding back to the drive control module (5), the drive control module (5) commands the motor (4) to rotate according to the feedback structure to compensate for the telescopic stroke error of the output shaft (3) caused by the moving distance error of the output shaft (3), and the drive control module (5) commands the motor (4) to rotate according to the feedback of the encoder (6) to compensate for the telescopic speed error of the output shaft (3) caused by the rotation speed error of the motor (4).

2. The high-precision fully closed-loop integrated electric cylinder according to claim 1, characterized in that: The feedback structure comprises a grating ruler (7) fixed outside the cylinder body (1) and extending along the extension and retraction direction of the output shaft (3), an indicator (8) fixed to the output shaft (3) and corresponding to the scale on the grating ruler (7) as the output shaft (3) retracts and retracts, and a grating cover (10) arranged outside the cylinder body (1) for shielding external light. The grating ruler (7) is connected to the drive control module (5) by signal.

3. The high-precision fully closed-loop integrated electric cylinder according to claim 1, characterized in that: The limiting structure comprises a matching component fixed to one end of the output shaft (3) close to the screw rod (2) and threadedly matched with the screw rod (2), and a guiding structure arranged between the matching component and the cylinder body (1) for driving the matching component to move along the axial direction of the screw rod (2).

4. The high-precision fully closed-loop integrated electric cylinder according to claim 3 is characterized in that: The matching component comprises a nut (11) matched with the screw rod (2) and a connecting pipe (12) whose two ends are respectively fixed to the nut (11) and the output shaft (3) and through which the screw rod (2) can be inserted.

5. The high-precision fully closed-loop integrated electric cylinder according to claim 4, characterized in that: The guide structure comprises a guide block (13) protruding from the outer ring wall of the connecting pipe (12) and a guide groove (14) provided on the cylinder body (1) for the guide block (13) to be inserted into and guide the guide block (13) to move along the axial direction of the screw rod (2).

6. The high-precision fully closed-loop integrated electric cylinder according to claim 5, characterized in that: A quick-installation structure for facilitating the disassembly and assembly of the guide block (13) is provided between the guide block (13) and the connecting pipe (12).

7. The high-precision fully closed-loop integrated electric cylinder according to claim 6, characterized in that: The quick-install structure comprises a slot (15) recessed on the outer ring wall of the connecting tube (12), an insert block (16) protruding on the guide block (13) and capable of being inserted into the slot (15) and adapted to the slot (15), and a fixing structure arranged between the insert block (16) and the slot (15).

8. The high-precision fully closed-loop integrated electric cylinder according to claim 7, characterized in that: The fixing structure comprises a through hole (17) arranged on the guide block (13), a threaded hole (18) arranged at the bottom of the slot (15), and a locking bolt (19); the locking bolt (19) passes through the through hole (17) and is tightly matched with the threaded hole (18).

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