Self-adaptive shape follow-up centering clamp and automatic clamping method

Abstract

The invention belongs to the technical field of clamping, and provides a self-adaptive shape follow-up centering clamp and an automatic clamping method. The self-adaptive shape follow-up centering clamp comprises an end cover, an outer circular ring, a floating shape follow-up positioning cylinder, a driving clamping cylinder, an inner circular ring, a hanging ring, a rib plate and a PLC control system. The automatic clamping method can replace a traditional process ring clamping method, self-adaptive shape follow-up positioning and clamping of the barrel workpiece are achieved, the process ring turning procedure is omitted, and material consumption is reduced. After the outer circular ring, the cylindrical roller bearing and the axis of the lathe spindle in the self-adaptive shape follow-up centering clamp are mounted consistently, it can be guaranteed that the middle barrel section coincides with the axis of the lathe spindle. Shape-following positioning of a blank barrel workpiece is achieved through the floating shape-following positioning cylinder, the barrel workpiece is clamped through the driving clamping cylinder, and it is guaranteed that stress is uniform while the axis of the barrel workpiece does not deviate. The device is achieved based on a PLC control system, the clamping force is quantitatively controlled through feedback adjustment of the oil pressure gauge and the proportional valve, and clamping deformation is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of clamping, and relates to an adaptive conformal centering fixture and an automatic clamping method. Background Art

[0002] There are many thin-walled cylindrical shells with large aspect ratios in the aerospace industry. Such thin-walled cylindrical shells are usually formed by spinning, and the roundness error of the profile is large. In order to meet the service performance requirements, several cylinders need to be welded before use. In order to meet the assembly requirements, the outer circle, inner hole and end face of the cylinder at both ends need to be turned based on the axis of the middle cylinder section, but the position error will be introduced between different cylinder sections due to welding, making the coaxiality of the entire cylinder impossible to guarantee. The length of the entire cylinder workpiece after welding can reach 2-3m. When processing both ends of the cylinder, the four-jaw chuck at one end of the lathe needs to be removed to avoid interference. However, clamping with only a single four-jaw chuck can easily cause the cylinder workpiece to overhang for a long time, causing the axis to shift and the accuracy cannot be guaranteed. Therefore, it is necessary to apply clamping constraints after the four-jaw chuck at one end of the lathe is removed to achieve the support effect, and at the same time ensure that the axis of the middle cylinder section is concentric with the lathe spindle before and after the four-jaw chuck is removed. Therefore, how to achieve clamping and ensure coaxiality has become an urgent problem to be solved.

[0003] In traditional turning processes, process rings are often used to solve this problem. The process ring is a symmetrical step structure with a large circular ring in the middle and symmetrical small circular rings at both ends. There are 18 bolts evenly distributed around the small circular rings on each side. The extension of the bolts is adjusted to adapt to the profile error of different cylindrical workpieces. During turning, firstly, a process ring is pre-fixed on both sides of the middle barrel section, and then the cylindrical workpiece is installed on the lathe, and the inner supports at both ends of the cylindrical workpiece are clamped with a four-jaw chuck. Then, the circular runout of the middle barrel section of the cylindrical workpiece is measured at the position close to the A-end barrel section and the B-end barrel section respectively. By adjusting the position of the four-jaw chuck jaws separately, the axis of the middle barrel section coincides with the axis of the lathe spindle. After the accuracy requirements are met, the outer circle of the A-end and B-end barrel sections is turned to light. Then, in order to minimize the cutting allowance of the process ring, the circular runout of the process ring needs to be measured, and the extension of each bolt on the small circular ring is continuously adjusted to make the axis of the process ring coincide with the axis of the cylindrical workpiece as much as possible. Since the roundness of the process ring cannot meet the coaxiality requirements, the large circle of the process ring needs to be turned to ensure accuracy. Finally, the inner circle and end face of the A-end barrel section are turned. After the A-end barrel section is processed, the direction of the barrel workpiece is turned. The jaws of the four-jaw chuck are adjusted based on the processed A-end barrel section and the process ring. The middle barrel section is concentric with the lathe spindle and then the B-end barrel section is processed.

[0004] The traditional clamping method relies on the process ring to ensure that the axis of the middle barrel section is concentric with the lathe spindle. Each time a barrel workpiece is processed, the process ring bolt needs to be adjusted, and then the large circle of the process ring is turned. In the mass manufacturing process, the consumption of process rings is huge, which greatly increases the manufacturing cost and causes a lot of waste. In addition, it takes workers 30-40 minutes to adjust the process ring bolts, which greatly reduces the processing efficiency. For this reason, it is urgent to develop an adaptive conformal centering fixture and automatic clamping method to replace the process ring, saving costs while improving efficiency. Summary of the invention

[0005] The problem to be solved is to overcome the shortcomings of the existing process ring clamping and provide an adaptive conformal centering fixture and an automatic clamping method.

[0006] The technical solution of the present invention:

[0007] An adaptive conformal centering fixture comprises an end cover 8, an outer ring 7, a floating conformal positioning cylinder 6, an active clamping cylinder 5, an inner ring 4, a lifting ring 14, a rib plate 15 and a PLC control system;

[0008] The floating conformal positioning cylinder 6 and the active clamping cylinder 5 are driven by oil pressure. The floating conformal positioning cylinder 6 can realize adaptive conformal positioning of the cylindrical workpiece 2. The active clamping cylinder 5 applies active clamping force to the cylindrical workpiece 2. The floating conformal positioning cylinder 6 first conforms to the shape, and then the active clamping cylinder 5 actively clamps to realize adaptive centering clamping. The inner ring 4 is used to install the floating conformal positioning cylinder 6 and the active clamping cylinder 5. The cylindrical roller bearing 9 installed on the outer side of the inner ring 4 realizes the turning rotation motion of the cylindrical workpiece 2. At the same time, the cylindrical roller bearing 9 is installed The position is concentric with the lathe spindle to ensure the coaxiality requirement; the end cover 8 realizes the side sealing of the centering fixture; different oil circuits are arranged in the outer ring 7 to realize sequential clamping; the lifting ring 14 is used for lifting and installation; the rib plate 15 is used to improve the overall rigidity; the PLC control system is used to realize the sequential control and automatic clamping of the centering fixture, and the monitoring and adjustment of the oil pressure gauge and the proportional valve are used to realize the quantitative application of the appropriate clamping force to the cylindrical workpiece 2 with different wall thicknesses; the adaptive conformal centering fixture can meet the adaptive conformal positioning and centering clamping functions of the cylindrical workpiece 2. The core technology of the present invention is: the adaptive conformal centering replaces the process of "turning process ring centering", which reduces the processing cost and improves the processing efficiency.

[0009] The outer ring 7 is a combined structure, divided into an upper part and a lower part. The upper part is a ring with a mounting hole inside the ring; the lower part is a rectangular base 704 for matching with the guide rail of the lathe 1; the connection between the upper ring and the lower rectangular base 704 is provided with an oil inlet hole and an oil drain hole; the outer ring 7 includes an active clamping cylinder oil inlet hole 701, a floating conforming positioning cylinder oil inlet hole 702, an oil drain hole 703, a rectangular base 704, and an inner ring mounting hole 705. , end cover fixing hole 706 and lifting ring mounting hole 707; the outer ring 7 is installed on the lathe 1 through the rectangular base 704 to ensure that the axis of the outer ring 7 is consistent with the axis of the main shaft of the lathe 1; the inner circumferential surface of the outer ring 7 is provided with an inner ring mounting hole 705, and the outer circumferential surface is provided with an active clamping cylinder oil inlet hole 701, a floating conformal positioning cylinder oil inlet hole 702, an oil drain hole 703 and a lifting ring mounting hole 707, and the outer surface is provided with an end cover fixing hole 706;

[0010] The inner ring 4 is a circular stepped ring, which includes four stepped sections, namely the first stepped ring 403, the second stepped ring 408, the third stepped ring 407 and the fourth stepped ring 406; the second stepped ring 408 with the largest diameter has an active clamping cylinder oil path 401 and a floating conformal positioning cylinder oil path 402 connected to the active clamping cylinder oil inlet hole 701 and the floating conformal positioning cylinder oil inlet hole 702 respectively; the outer side of the widest third stepped ring 407 is used to install a cylindrical roller bearing 9. Sixteen floating conformal positioning cylinder mounting holes 404 and active clamping cylinder mounting holes 405 for mounting active clamping cylinder 5 and floating conformal positioning cylinder 6 are evenly distributed inside the third step ring 407; the first step ring 403 and the fourth step ring 406 with the smallest diameter are used to mount the sealing ring 10; the inner ring 4 is mounted inside the outer ring 7 and fixed by the end cover 8; the cylindrical roller bearing 9 is mounted between the outer ring 7 and the inner ring 4, so as to ensure the centering and rotational movement of the cylindrical workpiece 2 after clamping;

[0011] The floating conformable positioning cylinder 6 is a hydraulic auxiliary support cylinder driven by oil pressure, and includes eight in total, which are evenly distributed in the mounting holes on the inner ring 4; when the hydraulic oil is supplied to the floating conformable positioning cylinder 6 through the floating conformable positioning cylinder oil circuit 402, the support rod extends, and after the support rod contacts the cylindrical workpiece 2, it automatically clamps, but does not provide clamping force, thereby realizing the conformable positioning function;

[0012] The active clamping cylinder 5 is a hydraulic clamping cylinder driven by oil pressure, and includes eight of them, which are evenly distributed in the mounting holes on the inner ring 4. When the hydraulic oil is supplied to the active clamping cylinder 5 through the active clamping cylinder oil circuit 401, the support rod extends, and by adjusting the hydraulic oil pressure, different clamping forces can be quantitatively provided, thereby realizing the clamping function.

[0013] The PLC control system can realize the automatic sequential action of the active clamping cylinder 5 and the floating conformal positioning cylinder 6, and is divided into an information control layer and a drive execution layer; the drive execution layer includes a hydraulic station, a proportional valve, a solenoid valve, an oil pressure gauge and an adaptive conformal centering fixture; the drive execution layer is equipped with two sets of proportional valves and solenoid valves, which are respectively used to control the hydraulic oil circuits of the active clamping cylinder 5 and the floating conformal positioning cylinder 6; among them, the hydraulic station is used to provide hydraulic oil; the proportional valve can accurately adjust the pressure; the solenoid valve is a switch valve, which is used to control the opening and closing of the oil circuit; the oil pressure gauge is used to detect the clamping force; the information control layer includes a host computer, a controller, a connector unit-IO slave station and a touch screen, and the communication adopts the EtherCAT bus mode. The connector unit-IO slave station is respectively connected to the proportional valve, the solenoid valve and the oil pressure gauge, and the current analog quantity is used to realize pressure monitoring; the automatic sequential clamping and releasing of this set of fixtures are realized through the PLC control system.

[0014] Furthermore, the hydraulic oil is divided into two paths. One path of hydraulic oil passes through the floating conformable positioning cylinder oil inlet hole 702 and the floating conformable positioning cylinder oil circuit 402 in sequence and is connected to the eight floating conformable positioning cylinders 6; the other path of hydraulic oil passes through the active clamping cylinder oil inlet hole 701 and the active clamping cylinder oil circuit 401 in sequence and is connected to the eight active clamping cylinders 5; the two paths of hydraulic oil share an oil drain hole 703; the eight active clamping cylinders 5 and the eight floating conformable positioning cylinders 6 are respectively connected in series in their respective oil circuits to ensure synchronous movement so that the cylindrical workpiece 2 is subjected to uniform force.

[0015] Furthermore, the active clamping cylinders 5 and the floating conformal positioning cylinders 6 are alternately distributed and evenly fixed in the mounting holes of the inner ring 4 .

[0016] Furthermore, the oil pressure gauge detects the hydraulic oil pressure and then feeds back to the proportional valve to quantitatively apply the clamping force. The oil pressure indication number can also accurately detect whether the clamp is in contact with the barrel workpiece.

[0017] Furthermore, the clamp of the present invention is different from the clamping method of the traditional process ring 13, which requires turning to ensure that the axis is consistent with the axis of the cylindrical workpiece 2. When installing the adaptive conformal centering fixture, it is only necessary to align the axis of the outer ring 7 and the cylindrical roller bearing 9 with the axis of the main shaft of the lathe 1 to ensure that the middle barrel section 201 of the cylindrical workpiece is coaxial with the main shaft of the lathe 1.

[0018] Furthermore, for blanks with different sizes of profiles, the floating conformal positioning cylinder 6 can achieve adaptive fit with the outer surface of the cylindrical workpiece 2. The floating conformal positioning cylinder 6 has a variety of specific strokes to meet the adaptive conformal positioning requirements of different profiles.

[0019] Furthermore, the floating conformal positioning cylinder 6 and the active clamping cylinder 5 are arranged in the circumferential direction at even intervals, and the number of the two is equal, so that the cylindrical workpiece is subjected to even force and the processing stability is improved.

[0020] Furthermore, the clamping end of the active clamping cylinder 5 is arc-shaped, which can effectively increase the contact area, and is made of a copper matrix material with a soft texture, which can reduce scratches.

[0021] Furthermore, the fixture of the present invention uses a cylindrical roller bearing 9 to achieve rotational motion. Compared with an angular contact ball bearing, the cylindrical roller bearing 9 has good pressure-bearing performance and improves the reliability of rotation.

[0022] Furthermore, the clamping sequence of the clamp of the present invention is to first perform conformal positioning and then clamp the cylindrical workpiece 2. After the floating conformal positioning cylinder 6 conformally contacts the cylindrical workpiece to achieve positioning, the active clamping cylinder 5 performs the clamping action. The conformal positioning of the floating conformal positioning cylinder 6 can effectively enhance the rigidity of the cylindrical workpiece 2 and reduce the clamping deformation caused by the clamping of the active clamping cylinder 5.

[0023] Furthermore, the number of active clamping cylinders 5 and floating conformal positioning cylinders 6 can be appropriately increased or decreased to meet the requirements of different barrel section diameters.

[0024] Furthermore, the PLC control system can realize sequential control of the solenoid valve through programming, thereby achieving one-button automatic clamping and releasing.

[0025] An adaptive conformal centering fixture and an automatic clamping method are implemented based on the adaptive conformal centering fixture and a PLC control system, and include the following steps:

[0026] The first step: install the adaptive conformal centering fixture on the guide rail of the lathe 1, and adjust the position of the outer ring 7 of the fixture so that it is coaxial with the main axis of the lathe 1.

[0027] Step 2: Adjust the claws of the four-claw chuck 3 of the lathe 1 to fix and clamp the cylindrical workpiece 2. At this time, the cylindrical workpiece 2 is located inside the fixture, and the floating conformal positioning cylinder 6 and the active clamping cylinder 5 are not oiled, that is, the fixture is not in a working state;

[0028] Step 3: Use a micrometer to detect the circular runout of the middle barrel section 201 of the barrel workpiece 2, and adjust the jaws of the four-jaw chuck 3 so that the circular runout of the barrel workpiece 2 meets the requirements. At this time, the axis of the barrel workpiece 2 coincides with the axis of the main shaft of the lathe 1;

[0029] Step 4: Turning the oxides on the outer circumferential surfaces of the A-end barrel section 202 and the B-end barrel section 203 of the barrel workpiece 2 to make the barrel workpiece have no obvious defects;

[0030] Step 5: Operate the touch panel to allow the fixture to pass oil, the floating conformal positioning cylinder 6 extends and contacts the cylindrical workpiece 2 and then clamps it, thus realizing the conformal positioning function; when the floating conformal positioning cylinder 6 contacts the cylindrical workpiece 2, the clamping force is set, and the active clamping cylinder 5 extends to clamp the cylindrical workpiece 2; after the cylindrical workpiece 2 is clamped, remove the four-claw chuck 3 on one side of the A-end barrel section 202;

[0031] Step 6: Process the inner hole and end surface of the A-end barrel section 202 of the barrel workpiece 2 until the processing is completed;

[0032] Step 7: Operate the touch panel to remove the oil pressure of the fixture, and release the cylindrical workpiece 2 after the active clamping cylinder 5 and the floating conformal positioning cylinder 6 are retracted; turn the direction of the cylindrical workpiece 2, use the four-jaw chuck 3 to clamp the cylindrical workpiece 2, and re-perform the circular runout detection on the middle barrel section 201 of the cylindrical workpiece 2. At this time, the circular runout measurement is based on the processed part, and the clamping claws of the four-jaw chuck 3 are adjusted to make the axis of the cylindrical workpiece 2 coincide with the axis of the main shaft of the lathe 1;

[0033] Step 8: Operate the touch panel to allow the fixture to pass oil, control the floating conformal positioning cylinder 6 to contact the cylindrical workpiece 2, and remove the four-claw chuck 3 on one side of the B-end barrel section 203 after the active clamping cylinder 5 clamps the cylindrical workpiece 2; process the inner hole and end surface of the B-end barrel section 203 of the cylindrical workpiece 2; until the B-end barrel section 203 of the cylindrical workpiece 2 is processed;

[0034] Step 9: Operate the touch panel to remove the oil pressure from the fixture, retract the active clamping cylinder 5 and the floating conformal positioning cylinder 6 to release the cylindrical workpiece 2, and complete the entire processing process.

[0035] Beneficial effects of the present invention:

[0036] (1) The adaptive conformal centering fixture and automatic clamping method provided by the present invention can replace the traditional process ring clamping method to achieve positioning and clamping of the cylindrical workpiece without turning process ring process, thereby reducing material consumption.

[0037] (2) After the outer rings and cylindrical roller bearings in the adaptive conformal centering fixture provided by the present invention are installed in accordance with the axis of the lathe spindle, the middle barrel section can be ensured to coincide with the axis of the lathe spindle. This replaces the adjustment step of the process ring bolt, greatly reduces the clamping time, and improves the processing efficiency.

[0038] (3) The fixture provided by the present invention realizes the conformal positioning of the blank cylindrical workpiece through eight floating conformal positioning cylinders, and clamps the cylindrical workpiece through eight active clamping cylinders, ensuring that the axis of the cylindrical workpiece does not deviate and the force is uniform. The top surface of the active clamping cylinder uses a curved copper column to contact the cylindrical workpiece, which can effectively increase the contact area and contact stiffness, greatly reduce the deformation of the cylindrical workpiece, and improve the processing accuracy.

[0039] (4) The automatic clamping method provided by the present invention is implemented based on a PLC control system, and uses feedback from an oil pressure gauge and a proportional valve to quantitatively control the clamping force, thereby reducing clamping deformation. One-button automatic clamping and release improves clamping efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is the lathe installation drawing of the adaptive conformal centering fixture.

[0041] Figure 2 This is the working status diagram of the fixture.

[0042] Figure 3 This is the installation diagram of the traditional ring clamp.

[0043] Figure 4 This is the overall picture of the fixture.

[0044] Figure 5 is a cross-sectional view of the fixture.

[0045] Figure 6 It is the outer donut diagram of the fixture.

[0046] Figure 7 This is the front view of the inner ring of the fixture.

[0047] Figure 8 It is an isometric view of the inner ring of the fixture.

[0048] Fig. 9 This is a cross-sectional view of the oil circuit of the active clamping cylinder of the fixture.

[0049] Fig.10 This is a cross-sectional view of the oil circuit of the fixture's floating conformal positioning cylinder.

[0050] Fig.11 This is the oil circuit diagram of the active clamping cylinder of the fixture.

[0051] Fig.12 This is the oil circuit diagram of the fixture's floating conformal positioning cylinder.

[0052] Fig.13 This is the diagram of the active clamping cylinder of the fixture.

[0053] Fig.14 It is a diagram of a cylindrical roller bearing.

[0054] Fig.15 It is the topology diagram of the PLC control system.

[0055] In the figure: 1 lathe; 2 cylindrical workpiece; 3 four-jaw chuck; 4 inner ring; 5 active clamping cylinder; 6 floating conformal positioning cylinder; 7 outer ring; 8 end cover; 9 cylindrical roller bearing; 10 sealing ring; 11 tool holder; 12 turning tool; 13 process ring; 14 lifting ring; 15 rib plate; 201 middle barrel section; 202A end barrel section; 203B end barrel section; 401 active clamping cylinder oil circuit; 402 floating conformal positioning cylinder oil circuit; 403 First step ring; 404 floating conformal positioning cylinder mounting hole; 405 active clamping cylinder mounting hole; 406 fourth step ring; 407 third step ring; 408 second step ring; 501 arc copper column; 701 active clamping cylinder oil inlet hole; 702 floating conformal positioning cylinder oil inlet hole; 703 oil drain hole; 704 rectangular base; 705 inner ring mounting hole; 706 end cover fixing hole; 707 lifting ring mounting hole. 1301 small ring; 1302 process ring bolt; 1303 large ring. DETAILED DESCRIPTION

[0056] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings and technical solutions.

[0057] In the implementation process of the fixture, the cylindrical workpiece 2 is made of high-strength alloy and consists of a middle barrel section 201, an A-end barrel section 202, and a B-end barrel section 203. The overall length of the cylindrical workpiece is 2200 mm, the A-end barrel section 202 and the B-end barrel section 203 are sections to be processed, with a diameter of 300 mm and a wall thickness of 1 mm, and the diameter of the middle barrel section 201 is 150 mm.

[0058] First, an adaptive conformal centering automatic fixture is installed, which includes an outer ring 7, an inner ring 4, a floating conformal positioning cylinder 6, an active clamping cylinder 5 and a PLC control system.

[0059] Assemble the outer ring 7: Install the ribs 15 on the rectangular base 704 and fix them with bolts. Install the lifting ring 14 on the lifting ring mounting hole 707 of the outer ring 7. At this time, the end cover 8 is not installed.

[0060] The inner ring 4 is assembled with the floating conformable positioning cylinders 6: eight floating conformable positioning cylinders 6 are evenly installed at the floating conformable positioning cylinder installation holes 404 on the inner ring 4, and the extending direction of the floating conformable positioning cylinders 6 is along the radius and points to the center of the circle.

[0061] Assemble the inner ring 4 and the active clamping cylinder 5: 8 active clamping cylinders 5 are evenly installed at the active clamping cylinder installation holes 405 on the inner ring 4, and are evenly arranged with the floating conformal positioning cylinders 6. The extension direction of the active clamping cylinder 5 is along the radius and points to the center of the circle.

[0062] Assemble the inner ring 4, the cylindrical roller bearing 9 and the sealing ring 10: Assemble the cylindrical roller bearing 9 with the third step ring 407 of the inner ring 4. Install the sealing ring 10 with the first step ring 403 and the fourth step ring 406 in a tight fit.

[0063] Assemble the inner ring 4 and the outer ring 7: The floating conformal positioning cylinder 6 is interconnected with the floating conformal positioning cylinder oil circuit 402, and the inner ring 4 is installed at the inner ring mounting hole 705 of the outer ring 7. The floating conformal positioning cylinder oil circuit 402 of the inner ring 4 is connected with the floating conformal positioning cylinder oil inlet hole 702 on the outer ring 7. The active clamping cylinder 5 is interconnected with the active clamping cylinder oil circuit 401, and the active clamping cylinder oil circuit 401 is connected with the active clamping cylinder oil inlet hole 701 on the outer ring 7. Finally, install the end covers 8 on both sides, fix the end covers 8 on the outer ring 7 with screws, and fix the inner ring 4.

[0064] PLC control system: according to Fig.15 The PLC control system topology diagram is based on the bus communication method to connect the host computer, controller, touch screen, and connector unit-IO slave. The analog signals of the proportional valve, solenoid valve, and oil pressure gauge are connected to the connector unit-IO slave. In the drive execution layer, the hydraulic station, proportional valve, solenoid valve, oil pressure gauge, and adaptive conformal centering fixture are connected in sequence through oil pipes. Finally, the connection between the oil circuit and the electrical equipment is completed.

[0065] At this point, an adaptive conformal centering automatic fixture is assembled.

[0066] The steps of using an adaptive form-fitting centering automatic fixture and a clamping method are as follows:

[0067] Step 1: Install the adaptive conformal centering fixture on the guide rail of lathe 1.

[0068] The assembled fixture is installed on the guide rail of the lathe 1 through the rectangular base 704 and is located in the middle of the four-jaw chuck 3 at both ends of the lathe.

[0069] Step 2: Hoist the cylindrical workpiece 2 above the lathe 1, and adjust the claws of the four-jaw chucks 3 at both ends of the lathe 1 to clamp the cylindrical workpiece 2.

[0070] Hoist the cylindrical workpiece 2 above the lathe 1, place the cylindrical workpiece 2 in the center of the fixture, and adjust the claws of the four-jaw chucks 3 at both ends of the lathe 1 to clamp the cylindrical workpiece 2. At this time, the fixture is not oiled, and the floating conformal positioning cylinder 6 and the active clamping cylinder 5 are both in the retracted state and are not in contact with the cylindrical workpiece 2.

[0071] Step 3: Adjust the axis of the middle barrel section 201 to be concentric with the main axis of the lathe 1, and turn the A-end barrel section 202 and the B-end barrel section 203 of the barrel workpiece 2 to light.

[0072] The middle barrel section 201 of the barrel workpiece 2 is tested for circular runout using a micrometer, and the jaws of the four-jaw chuck 3 on both sides of the lathe 1 are adjusted to make the circular runout of the barrel workpiece 2 meet the requirements. At this time, the axis of the middle barrel section 201 coincides with the axis of the main shaft of the lathe 1. The oxides on the outer circumferential surfaces of the A-end barrel section 202 and the B-end barrel section 203 of the barrel workpiece 2 are turned to make the barrel workpiece have no obvious defects.

[0073] Step 4: Operate the touch panel to open the oil circuit, realize adaptive conformal positioning and active clamping, and then perform fine machining on the A-end barrel section 202 of the barrel workpiece 2.

[0074] Operate the touch panel to pass oil through the fixture, and the floating conformal positioning cylinder 6 extends and contacts with the cylindrical workpiece 2 and then clamps it to realize the conformal positioning function. The oil pressure display number can be used to observe whether the floating conformal positioning cylinder 6 is in contact with the cylindrical workpiece 2. Then, input the clamping force and pass oil through the active clamping cylinder 5. The active clamping cylinder 5 extends to clamp the cylindrical workpiece 2. The clamping force can be controlled by the oil pressure gauge and the proportional valve to realize the active clamping function. Finally, remove the four-jaw chuck 3 at the end of the A-end barrel section 202, and perform end surface and inner hole processing on the A-end barrel section 202 of the cylindrical workpiece 2.

[0075] Step 5: Operate the touch panel to stop the oil supply, retract and reset the floating conformal positioning cylinder 6 and the active clamping cylinder 5, hoist and rotate the cylindrical workpiece 2, adjust the position of the jaws of the four-jaw chuck 3, and make the axis of the middle barrel section 201 coaxial with the main axis of the lathe 1.

[0076] The touch panel is operated to control the clamp to remove the oil pressure, retract the active clamping cylinder 5 and the floating conformal positioning cylinder 6 to release the cylindrical workpiece 2. Turn the direction of the cylindrical workpiece 2, adjust the jaws of the four-jaw chuck 3 to clamp the cylindrical workpiece 2, and re-test the circular runout of the middle barrel section 201 of the cylindrical workpiece 2. At this time, the circular runout measurement is based on the processed part, and the four-jaw chuck 3 is adjusted to make the axis of the middle barrel section 201 coaxial with the main axis of the lathe 1.

[0077] Step 6: Operate the touch panel control system to open the oil circuit, and after the cylindrical workpiece 2 is adaptively positioned and actively clamped, the B-end barrel section 203 of the cylindrical workpiece 2 is processed.

[0078] The touch panel is controlled to re-supply oil to the fixture, and the floating conformal positioning cylinder 6 is controlled to extend to contact and clamp the cylindrical workpiece 2. Then, the active clamping cylinder 5 is controlled to extend to clamp the cylindrical workpiece 2, and the four-jaw chuck 3 at the end of the B-end barrel section 203 is removed, and the end face and inner hole of the B-end barrel section 203 of the cylindrical workpiece 2 are turned. At this point, the A-end barrel section 202 and the B-end barrel section 203 of the cylindrical workpiece 2 are all processed.

[0079] Step 7: Operate the touch panel to control the fixture to remove the oil pressure, retract the active clamping cylinder 5 and the floating conformal positioning cylinder 6 to release the cylindrical workpiece 2, and hoist the cylindrical workpiece 2 to the material warehouse to complete the entire processing process.

[0080] The adaptive conformal centering fixture and automatic clamping method provided by the present invention can realize adaptive conformal centering clamping of blank cylindrical workpieces, without adjusting the fixture, simplifying the clamping steps, and the automated clamping method improves processing efficiency. The floating conformal positioning cylinder does not provide active clamping force and has a certain stroke, which can realize adaptive conformal positioning of different surfaces. The active clamping cylinder has a certain stroke. By cooperating with the oil pressure gauge and the proportional valve, it can provide suitable clamping force for different cylindrical workpieces, reducing clamping deformation. In addition, copper columns are used on the contact surface of the active clamping cylinder to reduce scratches and improve processing accuracy. Cylindrical roller bearings are used, which have good pressure-bearing capacity and improve the reliability of the fixture.

[0081] Although the embodiments of the present invention are described in the specification, these embodiments are only for reference and should not limit the protection scope of the present invention. Various omissions, substitutions and changes within the scope of the present invention should be included in the protection scope of the present invention.

Claims

1. An adaptive conformal centering fixture, characterized in that: The adaptive conformable centering fixture comprises an end cover (8), an outer ring (7), a floating conformable positioning cylinder (6), an active clamping cylinder (5), an inner ring (4), a lifting ring (14), a rib plate (15) and a PLC control system; The floating conformal positioning cylinder (6) and the active clamping cylinder (5) are driven by oil pressure. The floating conformal positioning cylinder (6) can realize adaptive conformal positioning of the cylindrical workpiece (2). The active clamping cylinder (5) applies active clamping force to the cylindrical workpiece (2). The floating conformal positioning cylinder (6) first performs conformal positioning and then the active clamping cylinder (5) actively clamps. The sequence is coordinated to realize adaptive centering clamping. The inner ring (4) is used to install the floating conformal positioning cylinder (6) and the active clamping cylinder (5). The cylindrical roller bearing (9) installed outside the inner ring (4) realizes the cylindrical workpiece (2). The workpiece (2) is turned and rotated, and at the same time, the cylindrical roller bearing (9) is installed concentrically with the lathe spindle to ensure the coaxiality requirement; the end cover (8) realizes the side sealing of the centering fixture; different oil circuits are arranged in the outer ring (7) to realize sequential clamping; the lifting ring (14) is used for lifting and installation; the rib plate (15) is used to improve the overall rigidity; the PLC control system is used to realize the sequential control and automatic clamping of the centering fixture, and the monitoring and adjustment of the oil pressure gauge and the proportional valve are used to realize the quantitative application of appropriate clamping force to the cylindrical workpiece (2) with different wall thicknesses.

2. The adaptive conformable centering fixture according to claim 1, characterized in that: The outer ring (7) is a combined structure, divided into an upper part and a lower part, the upper part is a ring with a mounting hole inside the ring; the lower part is a rectangular base (704) for cooperating with the guide rail of the lathe (1); an oil inlet hole and an oil drain hole are opened at the connection between the upper ring and the lower rectangular base (704); the outer ring (7) comprises an active clamping cylinder oil inlet hole (701), a floating conforming positioning cylinder oil inlet hole (702), an oil drain hole (703), a rectangular base (704), an inner ring mounting hole (705), and an end cover fixing hole (706). The outer ring (7) is mounted on the lathe (1) through a rectangular base (704) to ensure that the axis of the outer ring (7) is consistent with the axis of the main shaft of the lathe (1); the inner circumferential surface of the outer ring (7) is provided with an inner ring mounting hole (705), the outer circumferential surface is provided with an active clamping cylinder oil inlet hole (701), a floating conforming positioning cylinder oil inlet hole (702), an oil drain hole (703) and a lifting ring mounting hole (707), and the outer surface is provided with an end cover fixing hole (706); The inner ring (4) is a circular stepped ring, comprising four stepped sections, namely the first stepped ring (403), the second stepped ring 408, the third stepped ring (407) and the fourth stepped ring (406); the second stepped ring 408 with the largest diameter is provided with an active clamping cylinder oil circuit (401) and a floating conformal positioning cylinder oil circuit (402) connecting the active clamping cylinder oil inlet hole (701) and the floating conformal positioning cylinder oil inlet hole (702); the outer side of the widest third stepped ring (407) is used to install a cylindrical roller bearing (9); Sixteen floating conformal positioning cylinder mounting holes (404) and active clamping cylinder mounting holes (405) for mounting an active clamping cylinder (5) and a floating conformal positioning cylinder (6) are evenly distributed inside the stepped circular ring (407); the first stepped circular ring (403) and the fourth stepped circular ring (406) with the smallest diameter are used to mount a sealing ring (10); the inner circular ring (4) is mounted inside the outer circular ring (7) and fixed by an end cover (8); a cylindrical roller bearing (9) is mounted between the outer circular ring (7) and the inner circular ring (4), thereby ensuring the centering and rotational movement of the cylindrical workpiece (2) after clamping; The floating conformable positioning cylinder (6) is a hydraulic auxiliary support cylinder driven by oil pressure, and comprises eight of them in total, which are evenly distributed in the mounting holes on the inner ring (4); when the hydraulic oil is supplied to the floating conformable positioning cylinder (6) through the floating conformable positioning cylinder oil circuit (402), the support rod extends, and after the support rod contacts the cylindrical workpiece (2), it automatically clamps, but does not provide clamping force, thereby realizing the conformable positioning function; The active clamping cylinder (5) is a hydraulic clamping cylinder driven by oil pressure, and comprises eight of them in total, which are evenly distributed in the mounting holes on the inner ring (4); when the hydraulic oil is supplied to the active clamping cylinder (5) through the active clamping cylinder oil circuit (401), the support rod extends, and by adjusting the hydraulic oil pressure, different clamping forces can be quantitatively provided, thereby realizing the clamping function; The PLC control system can realize the automatic sequential action of the active clamping cylinder (5) and the floating conformal positioning cylinder (6), and is divided into an information control layer and a drive execution layer; the drive execution layer includes a hydraulic station, a proportional valve, a solenoid valve, an oil pressure gauge and an adaptive conformal centering fixture; the drive execution layer is equipped with two groups of proportional valves and solenoid valves, which are respectively used to control the hydraulic oil circuits of the active clamping cylinder (5) and the floating conformal positioning cylinder (6); wherein the hydraulic station is used to provide hydraulic oil; the proportional valve can accurately adjust the pressure; the solenoid valve is a switch valve, which is used to control the opening and closing of the oil circuit; the oil pressure gauge is used to detect the clamping force; the information control layer includes a host computer, a controller, a connector unit-IO slave station and a touch screen; the communication adopts the EtherCAT bus mode, the connector unit-IO slave station is respectively connected to the proportional valve, the solenoid valve and the oil pressure gauge, and the current analog quantity is used to realize pressure monitoring; the automatic sequential clamping and releasing of this set of fixtures are realized through the PLC control system.

3. The adaptive conformable centering fixture according to claim 2, characterized in that: The hydraulic oil is divided into two paths, one path of hydraulic oil passes through the floating conformable positioning cylinder oil inlet hole (702) and the floating conformable positioning cylinder oil circuit (402) in sequence and is connected to the eight floating conformable positioning cylinders (6); the other path of hydraulic oil passes through the active clamping cylinder oil inlet hole (701) and the active clamping cylinder oil circuit (401) in sequence and is connected to the eight active clamping cylinders (5); the two paths of hydraulic oil share an oil drain hole (703); the eight active clamping cylinders (5) and the eight floating conformable positioning cylinders (6) are respectively connected in series in their respective oil circuits to ensure synchronous movement so that the cylindrical workpiece (2) is subjected to uniform force.

4. The self-adaptive conforming centering fixture according to claim 1, characterized in that: The active clamping cylinder (5) and the floating conformal positioning cylinder (6) are alternately distributed and evenly spaced in the mounting holes in the circumferential direction, and the number of the two is equal; for blanks with different sized profiles, the floating conformal positioning cylinder (6) can achieve adaptive fitting with the outer surface of the cylindrical workpiece (2), and the floating conformal positioning cylinder (6) has a variety of specific stroke specifications to meet the adaptive conformal positioning of different profiles.

5. The self-adaptive conforming centering fixture according to claim 1, characterized in that: The oil pressure gauge detects the hydraulic oil pressure and then feeds back to the proportional valve to quantitatively apply the clamping force. The oil pressure indication number can also accurately detect whether the clamp is in contact with the barrel workpiece.

6. The self-adaptive conforming centering fixture according to claim 1, characterized in that: When installing the adaptive conformable centering fixture, it is only necessary to align the axis of the outer ring (7) and the cylindrical roller bearing (9) with the axis of the main shaft of the lathe (1) to ensure that the middle barrel section (201) of the barrel workpiece is coaxial with the main shaft of the lathe (1).

7. An automatic clamping method using an adaptive conformal centering fixture, characterized in that: Based on the adaptive conformal centering fixture and PLC control system, it includes the following steps: The first step is to install the adaptive conformal centering fixture on the guide rail of the lathe (1), and adjust the position of the outer ring (7) of the fixture so that it is coaxial with the main axis of the lathe (1). Step 2: Adjust the jaws of the four-jaw chuck (3) of the lathe (1) to fix and clamp the cylindrical workpiece (2). At this time, the cylindrical workpiece (2) is located inside the fixture, and the floating conformal positioning cylinder (6) and the active clamping cylinder (5) are not oiled, that is, the fixture is not in a working state; Step 3: Use a micrometer to detect the circular runout of the middle barrel section (201) of the barrel workpiece (2), and adjust the jaws of the four-jaw chuck (3) so that the circular runout of the barrel workpiece (2) meets the requirements. At this time, the axis center of the barrel workpiece (2) coincides with the axis center of the main shaft of the lathe (1); Step 4: turning the oxides on the outer circumferential surfaces of the A-end barrel section (202) and the B-end barrel section (203) of the barrel workpiece (2) to make the barrel workpiece free of obvious defects; Step 5: Operate the touch panel to allow oil to flow through the fixture, so that the floating conformal positioning cylinder (6) extends and contacts the cylindrical workpiece (2) and then clamps it, thereby realizing the conformal positioning function; when the floating conformal positioning cylinder (6) contacts the cylindrical workpiece (2), the clamping force is set, and the active clamping cylinder (5) extends to clamp the cylindrical workpiece (2); after the cylindrical workpiece (2) is clamped, remove the four-jaw chuck (3) on one side of the A-end barrel section (202); Step 6: Processing the inner hole and end surface of the A-end barrel section (202) of the barrel workpiece (2) until the processing is completed; Step 7: Operate the touch panel to remove the oil pressure from the fixture, and then release the cylindrical workpiece (2) after the active clamping cylinder (5) and the floating conformal positioning cylinder (6) are retracted; turn the direction of the cylindrical workpiece (2), use the four-jaw chuck (3) to clamp the cylindrical workpiece (2), and re-perform a circular runout test on the middle barrel section (201) of the cylindrical workpiece (2). At this time, the circular runout measurement is based on the processed part, and the clamping claws of the four-jaw chuck (3) are adjusted to make the axis of the cylindrical workpiece (2) coincide with the axis of the main shaft of the lathe (1); Step 8: Operate the touch panel to allow the fixture to flow oil, control the floating conformable positioning cylinder (6) to contact the cylindrical workpiece (2), and after the active clamping cylinder (5) clamps the cylindrical workpiece (2), remove the four-jaw chuck (3) on one side of the B-end cylindrical section (203); process the inner hole and end surface of the B-end cylindrical section (203) of the cylindrical workpiece (2); until the processing of the B-end cylindrical section (203) of the cylindrical workpiece (2) is completed; Step 9: Operate the touch panel to remove the oil pressure from the fixture, retract the active clamping cylinder (5) and the floating conformal positioning cylinder (6), release the cylindrical workpiece (2), and complete the entire processing process.

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