Engine top cover grinding device

Abstract

The present invention relates to the technical field of grinding devices, and in particular to an engine top cover grinding device, comprising a manipulator, a grinding tool, workbenches, a bottom plate, and a servo motor. Two workbenches used for placing workpieces are symmetrically mounted on the bottom plate; the servo motor used for driving the bottom plate to rotate is mounted at the bottom of the bottom plate; the manipulator is arranged beside one workbench; the grinding tool is mounted at the tail end of the manipulator; the two workbenches are respectively provided with a plurality of negative pressure apparatuses used for fixing the workpieces; and the negative pressure apparatuses do not interfere with the manipulator. According to the present invention, the negative pressure apparatuses fix the workpieces from the inside of the workpieces, thereby solving the problem that the surfaces of the workpieces that need to be ground cannot be completely exposed and the gripped positions of the workpieces cannot be ground due to an existing grinding device gripping the outer side walls of the workpieces by means of pneumatic grippers, reducing the workload of subsequent manual trimming, and improving the working efficiency.

Description

Engine cover grinding equipment Technical Field

[0001] The present invention relates to the technical field of grinding equipment, in particular to an engine upper cover grinding equipment. Background Art

[0002] Robotic grinding equipment is mainly composed of a six-axis manipulator, a grinding tool, a workpiece fixing device, etc.

[0003] The engine cover is generally made of aluminum alloy. Existing engine cover grinding equipment has two workbenches, one in the working position and the other in the loading position. Pneumatically clamped workpiece fixtures are designed on the workbenches. The two workbenches are connected by a base plate equipped with a drive element for swapping the positions of the two workbenches. A manipulator is fixedly installed next to one of the workbenches, and the manipulator is located in the working position. The workpiece is manually placed on the workbench in the loading position, clamped and fixed by the workpiece fixture, and the drive element is activated to transfer the workpiece from the loading position to the working position. The grinding tool at the end of the manipulator reciprocates to grind the workpiece surface. Simultaneously, the workbench in the working position returns to the loading position, the polished workpiece is removed, and a new workpiece is placed, repeating this cycle. In this process, the pneumatically clamped workpiece fixture clamps the outer wall of the workpiece with pneumatic jaws, preventing the workpiece from being fully exposed and unable to be polished to the clamped position. Subsequent manual finishing is required, resulting in low efficiency and a long production time.

[0004] To this end, an engine upper cover grinding device is proposed, which fixes the workpiece from the inside and completely exposes the surface of the workpiece that needs to be ground.

[0005] Summary of the Invention

[0006] The purpose of the present invention is to provide an engine cover grinding device, which is equipped with multiple negative pressure devices on the workbench to fix the workpiece, and the negative pressure devices do not interfere with the robot, so as to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] An engine cover polishing device includes a manipulator, a grinding tool, a workbench, a base plate, a servo motor, and a bottom bracket, wherein a servo motor is installed on the bottom bracket, and a base plate is installed on the output end of the servo motor, and two workbenches for placing workpieces are symmetrically installed on the base plate, and only one of the two workpieces is polished at a time, and the workpiece to be polished is transferred to the working position by rotating the base plate by the servo motor, and the polished workpiece is transferred to the discharge position for removal, wherein a manipulator is provided next to the workbench located at the working position, and a grinding tool is installed at the end of the manipulator, and the manipulator polishes the surface to be polished of the workpiece through the grinding tool, and a negative pressure device is provided under each of the two workbenches for fixing the workpiece, and the negative pressure device does not interfere with the manipulator, so that the polishing is completed in one go.

[0009] Preferably, the negative pressure device includes a plurality of negative pressure cylinders fixedly installed on the bottom of the workbench by threads, a rubber sheet is placed between the bottom of the workbench and the negative pressure cylinder to ensure the sealing of the negative pressure cylinder, a negative pressure hole connected to the negative pressure cylinder is opened on the workbench, the negative pressure hole is L-shaped, and the opening of the negative pressure hole is located on the side of the workbench, a dustproof cloth is placed in the negative pressure hole when no grinding operation is performed to prevent dust in the air from falling directly into the negative pressure hole after the workpiece is removed, a sealing groove is provided at the opening of the negative pressure hole, and the cross-section of the sealing groove is rectangular, a sealing ring is fixedly installed in the sealing groove by glue, and the cross-section of the sealing ring is rectangular, the cross-sectional area of ​​the sealing ring should be at least 85% of the cross-sectional area of ​​the sealing groove, the width of the sealing groove must be greater than the maximum width of the sealing ring after compression deformation, and when the sealing ring is installed in the sealing groove It should be 0.3-0.5mm higher than the sealing groove to ensure that the sealing ring can fully contact the inner wall of the workpiece. A piston is slidably installed in the negative pressure cylinder, and a piston rod is fixedly installed at the bottom of the piston. The negative pressure cylinder is cylindrical and coaxially arranged with the piston. A U-shaped groove is provided on the side of the piston, and a rubber seal is installed in the U-shaped groove to improve the sealing of the piston. The bottom of the piston rod is jointly connected with a driving device and a large spring. The servo motor drives the base plate to rotate forward and reverse alternately, exchanging the positions of the two workbenches. When the workbench at the loading position turns to the working position, the driving device drives the piston rod to move downward to form negative pressure in the negative pressure cylinder to fix the workpiece. When the workbench at the working position turns to the loading position, the large spring can reset the piston rod to release the workpiece fixation.

[0010] Preferably, the driving device includes a guide rod fixedly mounted on the base plate by a thread, and the guide rod is placed vertically, and its top is also fixedly mounted under the workbench by a thread, a connecting frame is slidably mounted on the guide rod, and the connecting frame is provided with a guide sleeve at the position where it cooperates with the guide rod. The use of the guide sleeve can prevent the connecting frame from directly rubbing against the rack and causing wear, thereby protecting the integrity of the connecting frame, and the guide sleeve is made of a material with a lower hardness than the rack, which can also prevent the guide rod from excessive wear, and the piston rods are all fixedly mounted on the connecting frame, and the movement of the piston rods can be synchronously controlled by the connecting frame to keep the pressure in the negative pressure cylinder consistent, thereby ensuring the stability of the workpiece fixation, and the servo motor is externally fixed The sleeve is provided with a shell, and the shell remains fixed. Soft ropes are fixedly connected to the connecting frame, and the two soft ropes pass through the base plate through the lock and are fixedly connected to the shell, and the connection position is on the shell away from the position of the manipulator, so that when the base plate rotates, the negative pressure cylinder on the workbench turned to the working position forms a negative pressure to fix the workpiece, and at the same time, the piston on the workbench turned to the discharge position is reset to release the fixation of the workpiece. Two rollers that cooperate with the soft ropes are symmetrically installed on the bottom of the base plate to avoid direct contact between the soft ropes and the base plate, reducing wear between the soft ropes and the sharp edges of the base plate. A large spring for resetting the connecting frame is installed under the connecting frame, and the large spring is sleeved on the guide rod.

[0011] When in use, place the workpiece to be polished on the workbench at the discharge position, start the servo motor to rotate the base plate to turn the workbench at the discharge position to the working position, and exchange positions with the workbench at the working position. At the same time, the soft rope turned to the working position will be wrapped around the outer shell, and the soft rope will be tightened to pull down the connecting frame it is connected to. The connecting frame drives the piston rod to move downward, so that negative pressure is formed in the workbench turned to the working position to fix the workpiece. At the same time, the soft rope of the workbench turned to the discharge position is unwound from the outer shell, and the connecting frame is reset under the action of the large spring, releasing the fixation of the polished workpiece.

[0012] Preferably, a protective shell is fixedly installed between the workbench and the base plate by threads, and the protective shell covers the negative pressure device to prevent dust from adhering to the components of the guide rod and the piston rod, which aggravates the wear of the matching position and affects the service life of the guide rod and the piston rod. The negative pressure cylinder is connected to an air outlet pipe, and the air outlet pipe passes through the protective shell and extends above the workpiece. An air valve switch is installed on the air outlet pipe, and the air valve switch has a handle. A control block that cooperates with the air valve switch is fixedly installed on the connecting frame by threads, and a rectangular hole is provided in the control block to cooperate with the handle of the air valve switch. After the piston moves downward to block the air outlet pipe, the air valve switch is opened through the rectangular hole. The air valve switch can discharge the compressed gas at the bottom of the negative pressure cylinder through the air outlet pipe and clean the grinding dust attached to the surface of the workpiece, reducing the workload of subsequent dust removal. The height of the piston is 2-3 times the diameter of the air outlet pipe to ensure that the piston still blocks the air outlet pipe when the air valve switch is opened through the rectangular hole. After the piston is reset, the air valve switch is closed through the rectangular hole.

[0013] Preferably, a one-way valve 1 is fixedly installed at the bottom of the negative pressure cylinder, and a one-way valve 2 is installed on the air outlet pipe. The one-way valve 1 is used for air intake of the negative pressure cylinder, and the one-way valve 2 prevents the negative pressure cylinder from taking in air from the air outlet pipe, and prevents dust from the external air from directly entering the negative pressure cylinder from the air outlet pipe. A filter tube is installed on the protective shell, and a long filter sponge is placed in the filter tube. The filter sponge is used to filter dust in the air, and the filter sponge is easy to replace after being clogged by dust.

[0014] During use, the workpiece is fixed, and the control block moves downward with the connecting frame. The piston moves downward to block the air outlet pipe, and then the piston continues to move downward. The air valve switch opens under the action of the rectangular hole. Because the piston height is 2-3 times the diameter of the air outlet pipe, the piston still blocks the air pipe after opening the air valve switch, and compresses the gas in the negative pressure cylinder at the bottom of the cylinder. At this time, the workpiece is fixed and moved to the working position. When the grinding is completed and the workpiece is released, the piston moves upward to expose the air outlet pipe blocked by the piston, and the compressed gas pushes open the one-way valve 2 and blows toward the surface of the workpiece to blow off the dust on the surface of the workpiece. When the compressed gas is discharged and the external air pressure is consistent, the one-way valve 2 is closed, and the piston continues to move upward. The negative pressure cylinder inhales air in the protective shell through the one-way valve 1, and the external gas enters the protective shell through the filter sponge of the filter tube. At this time, the workpiece is released, and the polished workpiece is moved to the loading position, and the workpiece is removed manually.

[0015] Preferably, a plurality of pressure blocks are slidably installed on the workbench, and the pressure blocks correspond to the control blocks one by one. The workbench is provided with a slideway that matches the pressure blocks. An inclined slider is fixedly installed on the end of the pressure block by welding, and a small spring is fixedly installed on the end of the inclined slider by welding, and the other end of the small spring is fixedly installed on the end of the slideway. A small cylinder that matches the inclined slider is fixedly installed on the top of the control block by welding, and the small cylinder is used to fix the inclined slider, and the pressure block is used to further fix the workpiece.

[0016] When in use, the control block moves downward with the connecting frame, the small cylinder releases the oblique slider, and the small spring pops out the pressure block to further fix the workpiece from the inside. After the control block moves upward with the connecting frame, the small cylinder retracts the pressure block into the slideway through the oblique slider, releasing the fixation of the workpiece.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The present invention fixes the workpiece from the inside of the workpiece by arranging multiple negative pressure devices on the workbench, thereby solving the problem that the existing grinding equipment clamps the outer wall of the workpiece by pneumatic clamps, so that the surface of the workpiece to be ground cannot be fully exposed and the workpiece cannot be ground to the clamped position. The workload of subsequent manual grinding is reduced, the work efficiency is improved, and the time cost required for production is reduced.

[0019] 2. The present invention has multiple pressure blocks slidably installed on the workbench, and the multiple pressure blocks correspond to multiple control blocks one by one. An inclined slider is fixedly installed on the end of the pressure block, and a small spring is installed on the end of the inclined slider. A small cylinder that cooperates with the inclined slider is installed on the top of the control block. When the control block and the piston rod move downward synchronously, the small cylinder will release the fixation of the pressure block, and the pressure block will pop out under the action of the small spring to further fix the workpiece.

[0020] 3. The present invention connects the air outlet pipe to the negative pressure cylinder and controls the air valve switch through the control block. After the workpiece is polished, the compressed gas in the negative pressure cylinder is automatically discharged from the air outlet pipe, and the polishing dust attached to the surface of the workpiece is cleaned, reducing the workload of subsequent dust removal. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG1 is a schematic diagram of the overall structure of the present invention when grinding a workpiece;

[0022] FIG2 is a front view of the present invention;

[0023] FIG3 is an enlarged cross-sectional view of portion A of FIG2 ;

[0024] FIG4 is an enlarged cross-sectional view of portion B of FIG2 ;

[0025] FIG5 is a cross-sectional view taken along line AA of FIG2 ;

[0026] FIG6 is a schematic structural diagram of a negative pressure device according to the present invention;

[0027] FIG7 is an enlarged cross-sectional view of portion C in FIG6 ;

[0028] FIG8 is a schematic diagram of the internal structure of the present invention;

[0029] FIG9 is an enlarged view of portion D of FIG8 ;

[0030] FIG10 is a schematic structural diagram of the control block of the present invention for opening the gas valve switch.

[0031] In the figure: 1. Robot; 2. Mold; 3. Workbench; 4. Bottom plate; 5. Servo motor; 6. Negative pressure cylinder; 7. Negative pressure hole; 8. Piston; 801. Piston rod; 9. Guide rod; 10. Connecting frame; 11. Housing; 12. Soft rope; 13. Large spring; 14. Valve switch; 15. Control block; 1501. Rectangular hole; 16. Protective shell; 17. One-way valve 1; 18. One-way valve 2; 19. Filter tube; 20. Pressing block; 2001. Inclined slider; 2002. Small spring; 21. Small cylinder; 22. Roller; 23. Exhaust pipe; 24. Workpiece. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] Example 1, please refer to Figures 1 to 10, the technical solution is as follows:

[0034] An engine cover grinding device includes a manipulator 1, a grinding tool 2, a workbench 3, a base plate 4, and a servo motor 5, wherein the base plate 4 is installed on the output end of the servo motor 5, and two workbench 3 for placing workpieces 24 are symmetrically installed on the base plate 4. The servo motor 5 rotates the base plate 4 to transfer the workpiece 24 to be ground to the working position, wherein a manipulator 1 is arranged next to the workbench 3 located at the working position, and a grinding tool 2 is installed at the end of the manipulator 1. The manipulator 1 grinds the surface to be ground of the workpiece 24 through the grinding tool 2. A negative pressure device is respectively provided on the two workbench 3 for fixing the workpiece 24, and the negative pressure device does not interfere with the manipulator 1, so that the grinding can be completed in one go.

[0035] The negative pressure device includes a plurality of negative pressure cylinders 6 fixedly mounted on the bottom of the workbench 3 by screw threads, a rubber sheet is placed between the bottom of the workbench 3 and the negative pressure cylinder 6, and a negative pressure hole 7 connected to the negative pressure cylinder 6 is opened on the workbench 3. The negative pressure hole 7 is L-shaped, and the opening of the negative pressure hole 7 is located on the side of the workbench 3. A sealing groove is provided at the opening of the negative pressure hole 7, and the cross-section of the sealing groove is rectangular. A sealing ring is fixedly installed in the sealing groove by glue, and the cross-section of the sealing ring is rectangular. The cross-sectional area of ​​the sealing ring should be at least 85% of the cross-sectional area of ​​the sealing groove. The width of the sealing groove must be greater than the maximum width of the sealing ring after compression deformation, and the sealing ring should be 0.3-0.5mm higher than the sealing groove when installed in the sealing groove to ensure that the sealing ring can fully contact the inner wall of the workpiece 24. A piston 8 is slidably installed in the negative pressure cylinder 6, and a piston rod 801 is fixedly installed at the bottom of the piston 8. The negative pressure cylinder 6 is cylindrical and coaxially arranged with the piston 8. A U-shaped groove is opened on the side of the piston 8, and a rubber seal is installed in the U-shaped groove. The bottom of the piston rod 801 is jointly connected to a drive device and a large spring 13.

[0036] The driving device includes a guide rod 9 fixedly mounted on the base plate 4 by a thread, and the guide rod 9 is placed vertically, and its top is also fixedly mounted under the workbench 3 by a thread, a connecting frame 10 is slidably mounted on the guide rod 9, and the connecting frame 10 is provided with a guide sleeve at the position where it cooperates with the guide rod 9, and the piston rod 801 is fixedly mounted on the connecting frame 10. The movement of the piston rod 801 can be synchronously controlled by the connecting frame 10 to keep the pressure in the negative pressure chamber consistent, thereby ensuring the stability of the workpiece 24. The outer fixed sleeve of the servo motor 5 is provided with a shell 11, and the shell 11 remains fixed, and the connecting frame 10 is fixed with a connecting rod 801. It is connected to a soft rope 12, and one end of the two soft ropes 12 passes through the base plate 4 and is fixedly connected to the shell 11 through a lock, and the connection position is on the shell 11 away from the manipulator 1, so that when the base plate 4 rotates, the negative pressure cylinder 6 on the workbench 3 turned to the working position forms a negative pressure to fix the workpiece 24, and at the same time, the piston 8 on the workbench 3 turned to the discharge position is reset to release the fixation of the workpiece 24. Two rollers 22 that cooperate with the soft rope 12 are symmetrically installed at the bottom of the base plate 4. A large spring 13 for resetting the connecting frame 10 is installed under the connecting frame 10, and the large spring 13 is sleeved on the guide rod 9.

[0037] A protective shell 16 is fixedly installed between the workbench 3 and the base plate 4 by threads. The protective shell 16 covers the negative pressure device. The negative pressure cylinder 6 is connected to an air outlet pipe 23, and the air outlet pipe 23 passes through the protective shell 16 and extends to above the workpiece 24. An air valve switch 14 is installed on the air outlet pipe 23, and the air valve switch 14 has a handle. The air valve switch 14 can discharge the compressed gas at the bottom of the negative pressure cylinder 6 through the air outlet pipe 23.

[0038] A control block 15 that cooperates with the air valve switch 14 is fixed on the connecting frame 10 by threads. A rectangular hole 1501 that cooperates with the handle of the air valve switch 14 is opened in the control block 15. After the piston 8 moves downward to block the air outlet pipe 23, the air valve switch 14 is opened through the rectangular hole 1501. The height of the piston 8 is 2-3 times the diameter of the air outlet pipe 23 to ensure that the piston 8 still blocks the air outlet pipe 23 when the air valve switch 14 is opened through the rectangular hole 1501. After the piston 8 is reset, the air valve switch 14 is closed through the rectangular hole 1501.

[0039] A one-way valve 17 is fixedly installed at the bottom of the negative pressure cylinder 6. The one-way valve 17 is used for the air intake of the negative pressure cylinder 6. A one-way valve 18 is installed on the air outlet pipe 23. The one-way valve 18 prevents the negative pressure cylinder 6 from taking in air from the air outlet pipe 23. A filter tube 19 is installed on the protective shell 16, and a long filter sponge is placed in the filter tube 19.

[0040] There are multiple pressure blocks 20 slidably installed on the workbench 3, and the pressure blocks 20 correspond one-to-one to the control block 15. The workbench 3 is provided with a slideway that cooperates with the pressure block 20. The end of the pressure block 20 is fixedly installed with an inclined slider 2001 by welding, and the end of the inclined slider 2001 is fixedly installed with a small spring 2002 by welding, and the other end of the small spring 2002 is fixedly installed with the end of the slideway. A small cylinder 21 that cooperates with the inclined slider 2001 is fixedly installed on the top of the control block 15 by welding. The small cylinder 21 is used to fix the inclined slider 2001, and the pressure block 20 is used to further fix the workpiece 24.

[0041] The specific workflow is as follows:

[0042] Before starting work, dustproof cloth is placed in the negative pressure hole 7 to prevent dust in the air from falling directly into the negative pressure hole 7 when there is no workpiece 24. The two workbenches 3 are rotated to the loading position and the working position respectively, and the soft rope 12 of the workbench 3 at the loading position is fixed to the outer shell 11 through the lock. The servo motor 5 is started to rotate forward, the positions of the two workbenches 3 are exchanged, and the soft rope 12 of the workbench at the loading position continues to be connected to the outer shell 11 through the lock.

[0043] When starting work, remove the dustproof cloth in the negative pressure hole 7 at the loading position, place the workpiece 24 to be polished on the workbench 3, start the servo motor 5 to reverse, turn the workbench 3 at the unloading position to the working position, and exchange positions with the workbench 3 at the working position. At the same time, the soft rope 12 turned to the working position will be wound around the shell 11. The soft rope 12 is tightened and the connecting frame 10 connected to it is pulled down. The connecting frame 10 drives the piston rod 801 to move downward, so that the negative pressure cylinder 6 in the workbench 3 turned to the working position forms a negative pressure to fix the workpiece 24, and the control block 15 moves downward with the connecting frame 10. When the piston 8 moves downward to block the air outlet pipe 23, it continues to move downward. The air valve switch 14 opens under the action of the rectangular hole 1501. Because the height of the piston 8 is 2-3 times the diameter of the air outlet pipe 23, the air pipe is still blocked after the air valve switch 14 is opened, and the gas in the negative pressure cylinder 6 is compressed at the bottom of the cylinder. After the control block 15 moves downward, the small cylinder 21 releases the oblique slider 2001, and the small spring 2002 pops out the pressure block 20 from the inside of the workpiece 24 to further fix the workpiece 24 and perform the workpiece 24 in the working position. Grinding, at the same time, the soft rope 12 of the workbench 3 turned to the discharge position is unwound from the shell 11, and the connecting frame 10 is reset under the action of the large spring 13. The dustproof cloth in the negative pressure hole 7 at the loading position is removed again, and the workpiece 24 to be polished is placed on the workbench 3. The servo motor 5 is started to rotate forward, and the positions of the two workbenches 3 are exchanged again. When the soft rope 12 of the workbench 3 turned to the discharge position is unwound from the shell 11, the piston 8 moves upward to expose the outlet pipe 23 blocked by the piston 8. The compressed gas pushes open the one-way valve 18 and blows toward the surface of the workpiece 24 and releases the workpiece. The dust on the surface of the workpiece 24 is blown away. When the compressed gas is discharged and the pressure is consistent with the external air pressure, the one-way valve 2 18 is closed, the piston 8 continues to move upward, and the negative pressure cylinder 6 inhales air in the protective shell 16 through the one-way valve 17. The external gas enters the protective shell 16 through the filter sponge of the filter tube 19. At this time, the negative pressure in the negative pressure cylinder 6 disappears, and the small cylinder 21 retracts the pressing block 20 into the slideway through the inclined slider 2001, releasing the fixation of the workpiece 24, and moving the polished workpiece 24 to the loading position. The workpiece 24 is removed manually, and the cycle continues until all the work is completed.

[0044] After the work is completed, dustproof cloth is placed in the negative pressure hole 7 again to prevent dust in the air from falling directly into the negative pressure hole 7 when there is no workpiece 24, and the lock is opened to release the connection between the soft rope 12 and the shell 11.

[0045] Example 2, please refer to Figures 1 to 10, the technical solution is as follows:

[0046] Different from the first embodiment, the bottom of the air outlet pipe 23 in the second embodiment is a retractable circular sleeve. The distance between the air outlet pipe 23 and the workbench 3 can be adjusted according to the different sizes of the manipulator 1. A suitable distance can be selected according to the actual working scenario. However, the dust on the circular sleeve must be cleaned regularly to avoid dust accumulation and affect the extension and retraction of the circular sleeve.

[0047] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An engine upper cover grinding device, comprising a manipulator (1), a grinding tool (2), a workbench (3), a base plate (4), a servo motor (5), and a bottom bracket, wherein: A servo motor (5) is mounted on the bottom bracket, and a bottom plate (4) is mounted on the output end of the servo motor (5), and two workbenches (3) for placing workpieces (24) are symmetrically mounted on the bottom plate (4), and the two workbenches (3) are respectively located at a loading position and a working position, wherein a manipulator (1) is arranged next to the workbench (3) located at the working position, and a grinding tool (2) is mounted at the end of the manipulator (1); It is characterized by further comprising: A negative pressure device is provided on each of the two workbenches (3) and is used for fixing the workpiece (24) from the inside.

2. The engine upper cover grinding device according to claim 1, characterized in that: The negative pressure device comprises a plurality of negative pressure cylinders (6) fixedly mounted on the bottom of the workbench (3), each of the workbench (3) being provided with a negative pressure hole (7) connected to the negative pressure cylinder (6), a piston (8) being slidably mounted in the negative pressure cylinder (6), and a piston rod (801) being fixedly mounted at the bottom of the piston (8), the bottom of the piston rod (801) being commonly connected with a driving device and a large spring (13), the servo motor (5) driving the bottom plate (4) to rotate forward and reverse alternately to exchange the positions of the two workbenches (3), when the workbench (3) at the loading position turns to the working position, the driving device drives the piston rod (801) to move downward to form a negative pressure in the negative pressure cylinder (6) to fix the workpiece (24), and when the workbench (3) at the working position turns to the loading position, the large spring (13) can reset the piston rod (801) to release the fixation of the workpiece (24).

3. The engine upper cover grinding device according to claim 2, characterized in that: The driving device comprises a guide rod (9) mounted on a base plate (4), a connecting frame (10) being slidably mounted on the guide rod (9), and a piston rod (801) being fixedly mounted on the connecting frame (10), an outer fixed sleeve of the servo motor (5) being provided with a shell (11), a soft rope (12) being fixedly connected to the connecting frame (10), and one end of the soft rope (12) passing through the base plate (4) and finally being fixed to the shell (11), and a large spring (13) for resetting the connecting frame (10) being mounted under the connecting frame (10).

4. The engine upper cover grinding device according to claim 2, characterized in that: The openings of the negative pressure holes (7) are all provided with sealing rings.

5. The engine upper cover grinding device according to claim 3, characterized in that: The negative pressure cylinder (6) is connected to an air outlet pipe (23), and an air valve switch (14) is installed on the air outlet pipe (23). A control block (15) that matches the air valve switch (14) is fixedly installed on the connecting frame (10), and a rectangular hole (1501) that matches the handle of the air valve switch (14) is opened in the control block (15).

6. The engine upper cover grinding device according to claim 5, characterized in that: A protective shell (16) is fixedly mounted on the bottom of the workbench (3).

7. The engine upper cover grinding device according to claim 6, characterized in that: A one-way valve (17) is fixedly installed at the bottom of the negative pressure cylinder (6), and a one-way valve (18) is installed on the air outlet pipe (23).

8. The engine upper cover grinding device according to claim 6, characterized in that: The protective shell (16) is provided with a filter tube (19), and a long filter sponge is placed in the filter tube (19).

9. The engine upper cover grinding device according to claim 8, characterized in that: A plurality of pressure blocks (20) are slidably mounted on the workbench (3), and the plurality of pressure blocks (20) correspond one to one with the plurality of control blocks (15); an inclined sliding block (2001) is fixedly mounted on the end of the pressure block (20); a small spring (2002) is mounted on the end of the inclined sliding block (2001); a small cylinder (21) matching the inclined sliding block (2001) is mounted on the top of the control block (15); the small cylinder (21) is used to fix the inclined sliding block (2001).

10. The engine upper cover grinding device according to claim 3, characterized in that: Two rollers (22) matched with the soft rope (12) are symmetrically mounted on the bottom of the base plate (4).

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