A flexible servo control mechanism for the upper plate working pressure of a double-sided polishing machine

Abstract

The application discloses a kind of upper disc working pressure flexible servo control mechanism of double-sided grinding and polishing machine, including lifting cylinder, movable cantilever beam, servo motor and its transmission parts are installed on the protruding support plate of movable cantilever beam, ball screw, screw nut;The screw nut is connected with the upper disc universal floating through drive head, compression spring, floating head, floating head connecting rod, ball head bearing connecting rod, ball head bearing, universal shaft;Compression spring and displacement sensor are installed between the drive head and floating head, and the upper disc is dynamically floating engagement with the drive yoke below by the roller yoke fixed on it to realize torque transmission and rotation.The application realizes the flexible servo closed-loop control of the vertical flexibility of upper disc working pressure by pneumatic and servo motor segmented stroke control, and realizes the flexible high-precision grinding and ultra-precision polishing processing of the full adhesion of upper and lower disc working surfaces and the upper and lower surfaces of workpiece by the floating transmission of upper disc pressure and rotating torque.

Description

Technical Field

[0001] This invention relates to the technical field of high-precision grinding machines and ultra-precision polishing machines, specifically to a flexible servo control mechanism for the upper plate working pressure of a double-sided grinding and polishing machine. Background Technology

[0002] A double-sided grinding and polishing machine is a precision surface processing device that uses upper and lower discs that rotate in opposite directions while the sun gear and ring gear rotate relative to each other in opposite directions. This causes the workpiece to rotate planetarily with the planetary gears. Simultaneously, pressure is applied to the upper and lower surfaces of the workpiece by the upper and lower discs. The surface material is then finely removed through the combined abrasive action of tiny abrasive particles in the grinding or polishing slurry. In the field of upper disc pressure control technology for high-precision double-sided grinding and polishing machines, the pressure drive source mainly includes pneumatic, hydraulic, and electric methods. Among these, pneumatic lifting and pressurization is the most common. The advantages of pneumatic operation are cleanliness and low cost, but the disadvantages are that air has a higher compressibility, resulting in significantly poorer pressure control stability and responsiveness compared to hydraulic and electric methods, which cannot meet the processing requirements of workpieces with higher technical demands. To meet the specific precision requirements of some workpieces, high-precision double-sided grinding and polishing machines with electric drive lifting and pressure sensor-controlled upper plate pressure have emerged, achieving relatively good results. However, from the perspectives of practicality, cost, and pressure control accuracy, there are three shortcomings: 1. The pressure sensor can transmit analog electrical signals through its pressure deformation, but its deformation is very small. When the upper plate first contacts the workpiece, it is insufficient to provide a buffering effect, requiring additional buffering devices to achieve soft contact start-up and flexible loading, which further increases the complexity and uncertainty of the pressure control process; 2. The upper plate lifting and loading use the same drive mechanism, located on the outer side of the upper and lower plates. The working pressure center of gravity of the upper plate is on the rotation axis of the upper and lower plates. The upper plate is raised or lowered by a cantilever beam or gantry beam to control the working pressure. The control weight includes not only the floating part of the upper plate but also the heavy support parts such as the cantilever beam or beam, which proportionally reduces the pressure control response of the system. At the same time, it proportionally increases the power and specifications of the components of the power system and transmission system, further increasing the manufacturing cost of precision parts. 3. Furthermore, the deformation caused by the eccentric load between the rotation axis of the floating upper plate and the driving force axis of the drive mechanism reduces the accuracy of the servo closed-loop control. Additionally, in terms of pressure and rotational torque transmission of the upper plate, the non-self-aligning connection between the upper plate and the pressure transmission component, or the non-floating engagement between the upper plate shift fork and the drive shift fork in some double-sided grinding and polishing machines, directly affects the safety of the upper plate working pressure control and the machining accuracy of the workpiece surface. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of the prior art by providing a flexible servo control mechanism for the upper plate working pressure of a double-sided grinding and polishing machine. By using segmented stroke control of cylinders and servo motors, and replacing pressure sensors with displacement sensors and compression springs, vertical flexible servo closed-loop control of the upper plate working pressure is achieved. Furthermore, through flexible floating transmission of upper plate pressure and rotational torque, flexible high-precision grinding or ultra-precision polishing is achieved, where the working surfaces of the upper and lower plates fully conform to the upper and lower surfaces of the workpiece.

[0004] To achieve the above technical objectives, the technical solution adopted by the present invention is as follows: a flexible servo control mechanism for the upper plate working pressure of a double-sided grinding and polishing machine, comprising a lifting cylinder, a movable cantilever beam, the movable cantilever beam being fixedly connected to the piston rod of the lifting cylinder, a transmission support, a servo motor, a synchronous belt and synchronous pulley, a lead screw bearing and its support, a ball screw, a lead screw nut, etc., being sequentially installed on the top of the protruding support plate of the movable cantilever beam; the lower end of the ball screw being installed on an auxiliary support; the lead screw nut being fixedly connected to a drive head; an upper guide rod and a lower guide rod being respectively installed on the lower frame of the drive head, and elastically connected to a floating head through upper and lower tension springs; the floating head being fixedly connected to a floating head connecting rod; a displacement sensor being installed inside the inner hole of the floating head connecting rod, the telescopic probe of the displacement sensor elastically abutting against the end face of the lower guide rod, the lower end of the floating head connecting rod being fixedly connected to the upper end of a ball bearing connecting rod through a locking nut, a ball bearing being installed at the lower end of the ball bearing connecting rod, and a universal joint being installed in the inner hole of the ball bearing. The universal joint is fixed to the end face of the central shaft of the upper plate. The upper plate achieves torque transmission and rotation through dynamic floating engagement between the roller fork and the drive fork below.

[0005] Furthermore, the total stroke of the upper plate is controlled in segments, including an upper stroke and an end stroke. The entire lifting section of the upper plate is rapidly raised and rapidly and slowly lowered by the lifting cylinder via a movable cantilever beam. When the lifting cylinder rises to the top position, the sensing boss and the cylinder top proximity sensor detect each other, activating the servo motor to raise the drive head to the upper position as well, maximizing the lifting stroke of the upper plate for easy loading and unloading of workpieces and cleaning and maintenance of the equipment's processing area. When the lifting cylinder descends to the bottom position, the roller bearing of the upper plate's roller fork automatically engages with the upper end of the groove in the drive fork, the sensing boss and the cylinder bottom proximity sensor detect each other, activating the servo motor to drive the floating section of the upper plate into the rapid and slow advance of the end stroke, along with sequential actions such as flexible soft contact with the workpiece surface and pressure flexible servo control.

[0006] Furthermore, the driving torque of the servo motor acts on the ball screw through the synchronous belt and synchronous pulley. The torque of the ball screw then acts on the screw nut and the drive head to generate an up-and-down axial thrust, which is further acted on the floating head through the compression spring.

[0007] Furthermore, in the above process, the auxiliary support serves as both a support component at the lower end of the ball screw and an anti-rotation and guiding component for the drive head.

[0008] Furthermore, the flexible transmission of the pressure from top to bottom on the upper plate is achieved by the floating head floating up and down on the upper and lower guide rods through the linear bearing seat and the linear bearing, and the omnidirectional floating of the ball bearing; the flexible transmission of the rotational torque of the upper plate is achieved by the cross-direction introduction of the roller fork and the drive fork, and the dynamic floating engagement between the roller bearing and the groove.

[0009] Furthermore, the floating head can slide up and down within the connecting rod guide sleeve via the floating head connecting rod, and the connecting rod guide sleeve is installed in the guide hole of the movable cantilever beam.

[0010] Furthermore, both the floating head and the drive head are frame-type structures located directly above the upper plate, and the ball screw drive shaft is located directly above the floating head, ensuring that the axis of the sensor's telescopic probe, the sliding guide axis of the floating head, and the drive axis of the ball screw all coincide on the same upper plate rotation axis, thereby realizing vertical drive and flexible servo closed-loop control of the upper plate working pressure.

[0011] The beneficial effects of this invention are: 1. The working pressure of the upper plate is achieved by the upper plate, compression spring, displacement sensor, floating head, ball screw, servo motor and other components in a coaxial vertical direction to realize flexible servo closed-loop control. It is a pure mechanical transmission, compact transmission, no eccentric force, faster pressure control response speed and higher accuracy.

[0012] 2. Segmented stroke control: First, a lifting cylinder on the side of the upper plate uses a cantilever beam to rapidly raise the upper part of the heavy-duty integrated upper plate, followed by rapid and slow descent; then, a servo motor vertically moves the floating part of the upper plate (e.g., ...) directly above the upper plate. Figure 7 The sequence of actions (shown) involves rapid traverse, slow traverse, soft contact with the workpiece, and pressure-flexible servo closed-loop control at the end of the stroke. Precise control of the servo motor and ball screw avoids eccentric deformation of the large stroke, heavy weight, and intermediate support components, making the upper plate working pressure servo control more sensitive, accurate, and effective.

[0013] 3. Enhanced Flexibility: Firstly, in terms of soft contact initiation when the upper plate initially contacts the workpiece, a compression spring is used for buffering, and the deformation of the compression spring is fed back by a displacement sensor. Under the control of the preset pressure value of the servo motor, a soft contact with the upper plate near zero pressure with the workpiece surface is achieved, ensuring a safe soft start for workpiece processing. Secondly, in terms of the top-down pressure drive of the upper plate, the up-and-down floating of the floating head and the omnidirectional floating of the ball bearing enable omnidirectional floating flexible processing of the upper plate. In addition, in terms of the rotational torque drive of the upper plate, a cross-shaped guide is used between the roller fork and the drive fork, and the dynamic floating engagement between the roller bearing and the groove further enables omnidirectional floating flexible processing where the working surfaces of the upper and lower plates fully conform to the upper and lower surfaces of the workpiece. Attached Figure Description

[0014] Figure 1 This diagram shows the upper plate in the top position, with the cylinder and lead screw fully raised.

[0015] Figure 2 This diagram illustrates the state of the lead screw being raised when the upper plate is at the bottom.

[0016] Figure 3 A cross-sectional diagram of the roller shift fork and the drive shift fork in a cross-shaped meshing state.

[0017] Figure 4 Schematic diagram of the working state of the lead screw servo with the upper plate in the lower position.

[0018] Figure 5 Schematic diagram of the flexible servo control mechanism for the upper plate working pressure

[0019] Figure 6 Schematic diagram of the cross-section of the upper floating head elastic displacement sensing structure.

[0020] Figure 7 This is a schematic diagram of the floating upper section.

[0021] The labels in the diagram are explained as follows: 01 Lower plate, 02 Drive fork, 03 Roller bearing, 04 Roller fork, 05 Lifting cylinder, 07 Movable cantilever beam, 09 Cylinder bottom proximity sensor, 10 Cylinder top proximity sensor, 11 Sensing boss, 14 Upper plate, 150,000

[0022] 16. 17. Ball joint bearing connecting rod; 18. Lead screw nut; 19. Ball screw; 20. Lead screw bearing and its support; 21. Transmission support; 22. Synchronous belt and synchronous pulley; 23. Servo motor; 24. Drive head; 25. Lead screw auxiliary support; 26. Ball joint bearing; 27. Floating head connecting rod; 28.

[0023] 29 Connecting rod guide sleeve, 30 Linear bearing, 31 Displacement sensor, 32 Floating head, 33 Compression spring, 34 Lower guide rod, 35 Upper guide rod, 36 Linear bearing housing, 37 Locking nut Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] Referring to Figures 1 to 7, the system includes a lifting cylinder (05) and a movable cantilever beam (07). The movable cantilever beam (07) is fixed to the piston rod of the lifting cylinder. On the top of the protruding support plate of the movable cantilever beam (07), a transmission support (20), a servo motor (23), a synchronous belt and synchronous pulley (21), a screw bearing and its support (19), a ball screw (18), and a screw nut (17) are installed in sequence. The lower end of the ball screw (18) is mounted on an auxiliary support (25). The screw nut (17) is fixed to the drive head (24). The lower frame of the drive head (24) is connected to the upper guide rod (34) and the lower guide rod (24) respectively. The rod (33) is fixedly connected and elastically connected to the floating head (31) through the upper and lower supporting compression springs (32); the floating head (31) is fixedly connected to the floating head connecting rod (27); a displacement sensor (30) is installed in the inner hole of the floating head connecting rod (27), and the telescopic probe of the displacement sensor (30) elastically abuts against the end face of the lower guide rod (33). The lower end of the floating head connecting rod (27) is fixedly connected to the upper end of the ball bearing connecting rod (16) through the locking nut (36). A ball bearing (26) is installed at the lower end of the ball bearing connecting rod (16), and a universal joint (15) is installed in the inner hole of the ball bearing (26). The universal joint (15) is fixedly connected to the end face of the central shaft of the upper plate (14). The upper plate (14) achieves torque transmission and rotation through the dynamic floating engagement of the roller fork (04) and the lower drive fork (02).

[0026] Referring to Figure 1, the total stroke of the upper plate (14) is controlled in two segments. The total stroke (=A) includes two segments: the upper stroke (=AET) and the lower stroke (=ET) (where T=the thickness of the workpiece being processed). The entire upper plate lifting part is raised and lowered by the lifting cylinder (05) through the movable cantilever beam (07) to achieve the raising and lowering of the upper stroke (=AET). When the lifting cylinder (05) rises to the top position, the sensing boss (11) senses the cylinder top position proximity sensor (10), and the starting servo motor (23) controls the drive head (24) to also rise to the upper position, so that the upper plate lift (=A) reaches the maximum, so as to facilitate loading and unloading of workpieces, cleaning and maintenance of the equipment processing area; as shown in Figures 2 and 4, when the lifting cylinder (05) falls to the bottom position, the roller bearing (03) of the upper plate roller fork (04) is just fully and automatically inserted into the upper end of the groove of the drive fork (02), the sensing boss (11) senses the cylinder bottom position proximity sensor (09), and the starting servo motor (23) drives the floating part of the upper plate (as shown in Figure 7) to start entering the end stroke (=ET) of fast advance, slow advance, soft contact with the upper surface of the workpiece and pressure soft servo control and other sequential actions.

[0027] Referring to Figure 5, the driving torque of the servo motor (23) is applied to the ball screw (18) through the synchronous belt and synchronous pulley (21). The torque of the ball screw (18) then acts on the screw nut (17) and the drive head (24) to generate an up-down axial thrust, and further acts on the floating head (31) through the compression spring (32).

[0028] Referring to Figure 6, with the action of the spring deformation force, the floating head (31) floats freely up and down on the upper guide rod (34) and lower guide rod (33) through the linear bearing seat (35) and linear bearing (29) fixed on it. Its floating amount is equal to the deformation amount of the spring (32). The deformation amount of the spring (32) is directly proportional to the axial thrust. The dynamic deformation amount of the spring (32) is converted into an electrical signal in real time by the displacement sensor (30) and fed back to the PLC and servo controller in the electrical control cabinet. The servo controller controls the servo motor to drive the ball screw to realize flexible servo closed-loop control of the working pressure of the upper plate. In addition, in the above process, the auxiliary support (25) serves as the support component of the lower end of the ball screw (18) and also as the anti-rotation and guiding component of the drive head (24).

[0029] Referring to Figure 6, the flexible transmission of pressure from top to bottom on the upper plate (14) is achieved by the dynamic superposition of the up-and-down floating of the floating head (31) and the omnidirectional floating of the ball bearing (26).

[0030] Referring to Figure 3, the flexible transmission of the rotation torque of the upper plate (14) is introduced in a cross direction by the roller fork (04) and the drive fork (02), and the roller bearing (03) and the groove are dynamically floating and meshing. The upper plate (14) can rotate freely on the XX axis and the YY axis at the same time. When the workpiece is subjected to the pressure of the upper plate and the rotation torque of the upper plate, it is ensured that the upper plate (14) can float and rotate freely in all directions with the lower plate (01) and the workpiece, thereby realizing flexible high-precision grinding and ultra-precision polishing processing in which the working surfaces of the upper plate (01) and the lower plate (14) are fully in contact with the upper and lower surfaces of the workpiece.

[0031] In addition, the floating head (31) and the drive head (24) are both frame structures located directly above the upper plate (14), and the drive shaft of the ball screw (18) is located directly above the floating head (31), ensuring that the telescopic probe axis of the sensor (30), the sliding guide axis of the floating head (31) and the drive thrust axis of the ball screw (18) are all coincident on the same upper plate rotation axis, realizing vertical drive and flexible servo closed-loop control of the working pressure of the upper plate.

Claims

1. A double-sided polishing machine's upper disc working pressure flexible servo control mechanism, comprising a lifting cylinder (05), a movable cantilever beam (07), characterized in that, The movable cantilever beam (07) is fixed to the piston rod of the lifting cylinder, and a transmission support (20), a servo motor (23), a synchronous belt and a synchronous pulley (21), a screw bearing and its support (19), a ball screw (18), and a screw nut (17) are sequentially installed on the top end of the protruding support plate of the movable cantilever beam (07). The lower end of the ball screw (18) is installed on a screw auxiliary support (25). The screw nut (17) is fixed to a driving head (24). The lower edge of the driving head (24) is fixed to an upper guide rod (34) and a lower guide rod (33), respectively, and is elastically connected to a floating head (31) through an upper and lower compression spring (32). The floating head (31) is fixed to a floating head connecting rod (27). A displacement sensor (30) is installed in the inner hole of the floating head connecting rod (27). The telescopic probe of the displacement sensor (30) is elastically abutted on the end face of the lower guide rod (33). The lower end of the floating head connecting rod (27) is fixed to the upper end of a ball head bearing connecting rod (16) through a locking nut (36). A ball head bearing (26) is installed at the lower end of the ball head bearing connecting rod (16). A universal shaft (15) is installed in the inner hole of the ball head bearing (26). The universal shaft (15) is fixed to the end face of the central shaft of an upper disc (14). The upper disc (14) is dynamically and floatingly engaged with the lower driving fork (02) through a roller fork (04) to realize torque transmission and rotation. The whole upper disc lifting part is quickly raised at the upper end stroke, quickly and slowly lowered by the movable cantilever beam (07) from the outside of the upper and lower discs through the lifting cylinder (05). When the lifting cylinder (05) rises to the top position, the sensing boss (11) is sensed by the cylinder top proximity sensor (10), the servo motor (23) is started, the driving head (24) is also raised to the upper position, and the upper disc (14) reaches the maximum lifting stroke. When the lifting cylinder (05) is lowered to the bottom position, the roller bearing (03) of the roller fork (04) is completely and automatically guided into the groove upper end of the driving fork (02), the sensing boss (11) is sensed by the cylinder bottom proximity sensor (09), the servo motor (23) is started to drive the upper disc floating part to start the fast and slow progress of the end stroke, and the flexible soft contact and pressure flexible servo control sequence action of the workpiece upper surface.

2. The dual-sided polishing machine's upper platen working pressure flexible servo control mechanism according to claim 1, wherein, The driving torque of the servo motor (23) acts on the ball screw (18) through the synchronous belt and the synchronous pulley (21). The torque of the ball screw (18) further acts on the screw nut (17) and the driving head (24) to generate an axial thrust, and further acts on the floating head (31) through the compression spring (32).

3. The dual-sided polishing machine's upper platen working pressure flexible servo control mechanism according to claim 2, wherein, The screw auxiliary support (25) is a support component for the lower end of the ball screw (18) and also serves as an anti-rotation and guide component for the driving head (24).

4. The flexible servo control mechanism for the upper plate working pressure of the double-sided grinding and polishing machine according to claim 1, characterized in that, The flexible transmission of the pressure from top to bottom of the upper disc (14) is realized by the up-and-down floating of the floating head (31) through the linear bearing seat (35) and the linear bearing (29) on the upper guide rod (34) and the lower guide rod (33) and the universal floating of the ball head bearing (26); the flexible transmission of the rotating torque of the upper disc (14) is realized by the crosswise guiding of the roller yoke (04) and the driving yoke (02) and the dynamic floating engagement between the roller bearing (03) and the groove.

5. The flexible servo control mechanism for the upper plate working pressure of the double-sided grinding and polishing machine according to claim 1, characterized in that, The floating head (31) can slide up and down in the connecting rod guide sleeve (28) through the floating head connecting rod (27), and the connecting rod guide sleeve (28) is installed in the guide hole of the movable cantilever beam (07).

6. The flexible servo control mechanism for the upper plate working pressure of the double-sided grinding and polishing machine according to claim 1, characterized in that, Both the floating head (31) and the driving head (24) are in the form of a frame structure, located directly above the upper disc (14), and the ball screw (18) driving shaft is located directly above the floating head (31), ensuring that the axis of the telescopic probe of the displacement sensor (30), the sliding guide axis of the floating head (31) and the driving thrust axis of the ball screw (18) all coincide on the same upper disc rotating axis, realizing the vertical driving and flexible servo closed-loop control of the working pressure of the upper disc.

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