Flexible fixture and using method suitable for large-diameter thin ring machining

Abstract

This application relates to the field of tooling and fixture technology, and discloses a flexible fixture and its method of use suitable for machining large-diameter thin circular ring parts. The fixture includes flexible grippers, each comprising an assembly frame fixedly connected to a turntable and equipped with a guide rail. Two sets of radially movable support frames are movably connected to the guide rail. Each set of support frames is equipped with fan-shaped grippers with fan-shaped steps. A clamping cylinder is provided between the two sets of support frames, and a locking cylinder is provided on the side wall of each support frame. The locking cylinder extends and presses against the assembly frame to lock the position of the support frame. This flexible fixture and its method of use for machining large-diameter thin circular ring parts features nine sets of flexible grippers evenly distributed on the circular ring, clamping radially both internally and externally, increasing the force-bearing area, reducing deformation, and meeting high-precision machining requirements. It employs passive automatic auxiliary support technology, relying on the opening and closing of the fan-shaped grippers to achieve support, adapting to high-precision machining with poor flatness or rough surface positioning, and avoiding axial deformation and vibration.

Description

Technical Field

[0001] This application relates to the field of tooling and fixture technology, and in particular to a flexible fixture suitable for machining large-diameter thin circular rings and its usage method. Background Technology

[0002] In the field of machining, the deformation problem during the machining of thin-walled circular parts (such as large bearing rings and ring-shaped structural components for aerospace applications) has long constrained their machining accuracy and production efficiency. Due to their thin walls and weak overall rigidity, these parts are highly susceptible to external interference during machining. Clamping force, as an external force acting directly on the part, is the core factor inducing clamping deformation and machining vibration. Ultimately, this makes it difficult to meet key accuracy indicators such as roundness and flatness, becoming a major bottleneck affecting machining quality and a primary cause of machining errors.

[0003] Currently, the mainstream clamping methods for thin ring-shaped parts are divided into two categories: radial clamping with fan-shaped claws and axial clamping. Although both aim to reduce clamping deformation, they have significant limitations in practical applications and cannot cover the machining needs of all specifications and working conditions.

[0004] Limitations of radial clamping with fan-shaped claws: This method achieves clamping through multi-point contact between the fan-shaped claws and the inner / outer circular surfaces of the part, enabling the radial clamping force to be evenly distributed around the circumference of the part, effectively reducing local stress concentration. Therefore, it is more suitable for thin ring-shaped parts with small diameters and high-precision positioning reference surfaces (precision references) that have already been machined. However, for large-diameter thin ring-shaped parts (such as large ring parts with a diameter exceeding 1m), the traditional single-sided radial clamping structure has significant drawbacks: due to the large diameter and weaker rigidity of the part, the single-sided radial clamping force is prone to cause unilateral force imbalance on the part, resulting in an increase in the radial deformation of the fixture itself. At the same time, the part is prone to overall warping deformation (such as an elliptical or wavy cross-section), which seriously damages the roundness accuracy of the part. Multiple rework corrections are required after machining, significantly reducing production efficiency.

[0005] Limitations of Axial Clamping: Axial clamping uses a pressure plate or ring to press the part axially onto the fixture's positioning surface. On one hand, it ensures a tight fit between the part and the positioning surface, enhancing the overall rigidity of the part and reducing machining vibration. On the other hand, this method has no radial clamping force, avoiding circumferential deformation caused by radial forces, which is advantageous in specific scenarios. However, this method has extremely high requirements for the flatness of the positioning surface: if the positioning surface is an unprocessed blank surface (high surface roughness, large flatness error), or if the flatness of the positioning surface deteriorates after long-term use, the axial clamping force will cause the part to undergo synchronous axial deformation (such as local depressions or bulges) with the concave and convex shape of the positioning surface, resulting in the flatness of the part's end face exceeding the tolerance. Even if the positioning surface accuracy meets the standard, for parts with extremely thin walls (such as less than 5mm), excessive axial pressure may still cause the part to warp. Therefore, this method is completely unsuitable for parts with poor positioning surface accuracy or extremely thin walls.

[0006] In summary, neither of the two existing mainstream clamping methods can meet the clamping requirements of thin ring-shaped parts under complex working conditions such as "large diameter, low positioning surface accuracy, and thin wall thickness". There is an urgent need for a new clamping solution that can overcome the limitations of application and effectively control clamping deformation in order to solve the machining accuracy problem that has long plagued the industry. Summary of the Invention

[0007] This application proposes a flexible fixture and its usage method suitable for machining large-diameter thin circular ring parts. For clamping, nine sets of flexible jaws are evenly distributed on the circular ring, clamping radially both internally and externally, increasing the force-bearing area, reducing deformation, and meeting high-precision machining requirements. A passive automatic auxiliary support technology is employed, relying on the opening and closing of fan-shaped jaws for support, adapting to high-precision machining with poor flatness or rough surface positioning, avoiding axial deformation and vibration. For automatic adjustment and positioning, after fixing the fixture body, the internal and external fan-shaped jaws, driven by hydraulic cylinders, constrain the thin circular ring part. A vision unit and the flexible jaw system work together to adjust the workpiece position, ensuring clamping accuracy and reducing positioning errors and clamping deformation. Simultaneously, it features full-process detection capabilities; online automatic vision detection can dynamically monitor the machining results and process, enabling quality prediction and eliminating potential quality issues.

[0008] To achieve the above objectives, this application adopts the following technical solution: a flexible fixture suitable for machining large-diameter thin circular ring parts, including a turntable and a support, wherein the support is connected to a vision unit for monitoring the center coordinates of the workpiece;

[0009] The turntable is provided with at least six sets of flexible grippers evenly distributed along the circumference, of which three sets of flexible grippers are adjustment grippers and the rest are fixed grippers, and the included angle between the two sets of adjustment grippers is 120 degrees.

[0010] The flexible gripper includes an assembly frame fixedly connected to the turntable and equipped with a guide rail. The guide rail is movably connected to two sets of radially movable support frames. Both sets of support frames are equipped with fan-shaped claws with fan-shaped steps. A clamping cylinder is provided between the two sets of support frames. A locking cylinder is provided on the side wall of the support frame. The locking cylinder extends and presses against the assembly frame to lock the position of the support frame.

[0011] The support frame on the adjustment clamp is connected to the servo motor via a lead screw pair. The servo motor adjusts the position of the adjustment clamp according to the coordinate information to center the workpiece.

[0012] Furthermore, the two sets of sector-shaped claws are an inner sector-shaped claw and an outer sector-shaped claw, both of which are fixedly connected to the support frame. The outer sector-shaped claw has a concave sector-shaped step that matches the outer sidewall of the workpiece, while the inner sector-shaped claw has a convex sector-shaped step that matches the inner sidewall of the workpiece.

[0013] Furthermore, to ensure that the flexible gripper is initially in the appropriate position and matches the contour of the workpiece, so that no additional adjustment is needed when placing the workpiece, a support frame on the adjusting clamp is connected to the lead screw pair via an elastic sleeve, and the servo motor is connected to the lead screw pair via a nut. A support frame on the fixed clamp is connected to the assembly frame via an adjusting bolt, and the adjusting bolt is connected to the support frame via an elastic sleeve.

[0014] Furthermore, the flexible gripper has at least two sets of auxiliary supports in one of its fan-shaped claws. The auxiliary supports include a horizontal pressure bar, a movable sleeve, and a vertical support column. One end of the movable sleeve is connected to the horizontal pressure bar via a front spring, and the other end is connected to the fan-shaped claw via a rear spring. The fan-shaped claw has a sliding groove corresponding to the auxiliary support. The top of the movable sleeve has an inclined surface, which is slidably connected to the bottom of the support column. The inclination angle of the inclined surface is less than or equal to the friction angle.

[0015] Furthermore, in order to facilitate the adjustment of the relative position between the fan-shaped claw and the support frame, the support frame is connected to the fan-shaped claw through a transition plate. The transition plate is fixedly connected to the support frame by bolts. The surfaces of the transition plate and the fan-shaped claw facing each other are provided with triangular tooth grooves. The fan-shaped claw is provided with waist holes. The bolts pass through the waist holes and the transition plate to press the fan-shaped claw tightly onto the transition plate. A flat key is also provided between the fan-shaped claw and the transition plate. The orientation of the flat key and the triangular tooth grooves are perpendicular to each other.

[0016] Furthermore, in each set of adjustment clips, at least one sector claw is an adjustable sector claw. The adjustable sector claw includes a base plate fixedly connected to the transition plate. The outer side of the base plate has a side baffle. The middle part of the side baffle is connected to a sector plate through a hinge block. The outer side of the sector plate and the side baffle are arched together, with a gap between them. The gap is filled with an elastic element.

[0017] Furthermore, each set of adjustment clips includes an adjustable fan-shaped claw, the bottom of which is higher than the bottom of the other fan-shaped claw and the fan-shaped claw on the positioning claw, and the auxiliary support in the adjustment clip is mounted on the other fan-shaped claw.

[0018] Furthermore, the bottom of the sector plate is provided with several ball bearings, and the sector plate is movably connected to a sliding plate through the ball bearings. The sliding plate is fixedly connected to the supporting base plate by bolts. An elastic band is provided between the sector plate and the sliding plate, and the elasticity of the elastic band causes the supporting base plate to return to the center.

[0019] A method for using a flexible fixture suitable for machining large-diameter thin circular ring parts, wherein the workpiece is fixed using the aforementioned flexible fixture suitable for machining large-diameter thin circular ring parts.

[0020] The beneficial effects of this invention are as follows:

[0021] 1. Fixture clamping rigidity and deformation control: This special fixture has multiple sets of fan-shaped claws evenly distributed, with their radial clamping positions located on the annular belt. Compared to clamping only the outer or inner circle, this clamping method increases clamping rigidity, significantly reducing radial deformation, axial deformation, and warping deformation during clamping, thus meeting the requirements of CNC vertical lathe machining of high-precision thin annular parts.

[0022] 2. Passive Automatic Auxiliary Support Function: This fixture employs passive automatic auxiliary support technology, achieving auxiliary support solely through the opening and closing of the fan-shaped jaws. Specifically, the support column stops moving after rising and contacting the workpiece. This auxiliary support structure can withstand 5-6 times the cutting force. This design is suitable for high-precision machining of thin ring parts with poor flatness or rough surfaces, effectively avoiding deformation and vibration problems caused by poor axial positioning rigidity when subjected to axial cutting forces.

[0023] 3. Automatic adjustment and positioning accuracy assurance of the fixture: For this special fixture for machining thin rings, after the position of the fixture body is fixed, the inner and outer sector-shaped jaws, driven by the hydraulic cylinder, can simultaneously constrain the thin ring part. With the synergistic effect of the vision unit and the flexible gripper system, the fixture can automatically adjust according to different outer circle shapes, firmly clamping the workpiece and preventing displacement during machining, thereby ensuring the positional accuracy of the workpiece after clamping. This positioning method helps reduce positioning errors and clamping deformation, improving the machining accuracy of the workpiece.

[0024] 4. Full-process inspection: The online visual automatic inspection function differs from traditional contact-based inspection. This function not only inspects the processing results but also continuously monitors for abnormal cutting, overcutting, and other abnormal conditions during processing, achieving dynamic monitoring of the processing. This approach allows for quality prediction, eliminating quality issues at their inception. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort:

[0026] Figure 1 This is a schematic diagram of Embodiment 1 of the present invention;

[0027] Figure 2 This is a top view of Embodiment 1 of the present invention;

[0028] Figure 3 This is a top view of the flexible gripper in Embodiment 1 of the present invention;

[0029] Figure 4 For the present invention Figure 3 Sectional view at point AA;

[0030] Figure 5 This is a schematic diagram of the support frame and its connection structure in Embodiment 1 of the present invention;

[0031] Figure 6 This is a schematic diagram of the transition plate in Embodiment 1 of the present invention;

[0032] Figure 7 This is a schematic diagram of the auxiliary support in Embodiment 1 of the present invention;

[0033] Figure 8 This is a schematic diagram of the hydraulic module in Embodiment 1 of the present invention;

[0034] Figure 9 This is a top view of the flexible gripper in Embodiment 2 of the present invention;

[0035] Figure 10 This is a schematic diagram of the support frame and its connection structure in Embodiment 2 of the present invention;

[0036] Figure 11 This is a schematic diagram of the adjustable sector claw in Embodiment 2 of the present invention;

[0037] Figure 12 This is a schematic diagram of the sector plate and side baffle in Embodiment 2 of the present invention;

[0038] Figure 13 This is a schematic diagram of the sliding plate and the supporting base plate in Embodiment 2 of the present invention.

[0039] In the diagram: 1. Turntable; 2. Flexible gripper; 201. Assembly frame; 202. Guide rail; 203. Support frame; 204. Transition plate; 205. Outer fan-shaped gripper; 206. Inner fan-shaped gripper; 207. Waist hole; 208. Adjustable fan-shaped gripper; 2081. Base plate; 2082. Side baffle; 2083. Hinge block; 2084. Fan-shaped plate; 2085. Elastic element; 2086. Support base plate; 2087. Elastic strap; 2088. Ball bearing. ; 2089, Sliding plate; 209, Clamping cylinder; 210, Locking cylinder; 211, Triangular tooth groove; 212, Elastic sleeve; 213, Flat key; 3, Adjusting bolt; 4, Servo motor; 5, Lead screw pair; 6, Bracket; 7, Vision unit; 8, Auxiliary support; 801, Horizontal pressure bar; 802, Front spring; 803, Moving sleeve; 804, Rear spring; 805, Support column; 806, Inclined surface; 9, Hydraulic module; 10, Workpiece. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Example 1, please refer to Figure 1 and Figure 2 A flexible fixture suitable for machining large-diameter thin circular ring parts includes a hydraulic module 9 and a turntable 1 and a bracket 6 installed on the machining equipment. The turntable 1 is provided with several sets of flexible grippers 2 evenly distributed along the circumference. There are at least six sets of flexible grippers 2, which are multiples of three. Among them, three sets of flexible grippers 2 are adjustment grippers, and the rest are fixed grippers. The included angle between two sets of adjustment grippers is 120 degrees. There are 1-2 sets of fixed grippers between any two sets of adjustment grippers.

[0042] Please see Figures 3-5The flexible gripper 2 includes an assembly frame 201 fixedly connected to the turntable 1. The transverse centerline of the assembly frame 201 points to the center of the turntable 1. The assembly frame 201 is fixedly connected to guide rails 202, which are provided in two sets. The two sets of guide rails 202 are located on both sides of the assembly frame 201, parallel to the transverse centerline. The guide rails 202 are fixed to the assembly frame 201 by bolts. Two sets of support frames 203 are movably connected to the guide rails 202. Both sets of support frames 203 are provided with fan-shaped claws, which have fan-shaped steps. The two sets of fan-shaped claws are an inner fan-shaped claw 206 and an outer fan-shaped claw 205. The outer fan-shaped step is concave inward, interacting with the workpiece 1. The outer side wall of the workpiece 10 is adapted, that is, the outer fan-shaped claw 205 has a concave fan-shaped step, and the fan-shaped step on the inner side protrudes outward to adapt to the inner side wall of the workpiece 10, that is, the inner fan-shaped claw 206 has an outward protruding fan-shaped step. A clamping cylinder 209 is provided between the two sets of support frames 203. The clamping cylinder 209 extends and retracts to make the two sets of support frames 203 move away from each other or move closer to each other, thereby making the two sets of fan-shaped claws move away from each other or move closer to each other, so as to release or clamp. A locking cylinder 210 is provided on the side wall of the support frame 203. When the two sets of fan-shaped claws clamp the workpiece 10, the locking cylinder 210 extends and presses against the assembly frame 201 to lock the position of the support frame 203 and maintain the clamping state.

[0043] To ensure the flexible gripper 2 is initially positioned correctly and matches the contour of the workpiece 10, a support frame 203 on the adjusting clamp is connected to a lead screw assembly 5 via an elastic sleeve 212. A servo motor 4 is mounted on the turntable 1, and the servo motor 4 is connected to the lead screw assembly 5 via a nut. The servo motor 4 drives the nut to rotate, thereby moving the lead screw assembly 5. The lead screw assembly 5 then moves the support frame 203, stopping it at a set position. A support frame 203 on the fixed clamp is connected to the assembly frame 201 via an adjusting bolt 3. The adjusting bolt 3 is connected to the support frame 203 via the elastic sleeve 212. Adjusting the relative position of the adjusting bolt 3 and the turntable 1 pushes the support... The frame 203 moves, positioning the two fan-shaped claws on the fixed clamp in the set position. After adjustment, the spacing and position of each set of fan-shaped claws are exactly matched with the contour of the workpiece 10. After the workpiece 10 is loaded, the two fan-shaped claws on each set of flexible clamps 2 are exactly located on the inner and outer sides of the workpiece 10. When clamping, the clamping cylinder 209 retracts, and the two sets of fan-shaped claws move toward the workpiece 10 to clamp the workpiece 10. The elastic sleeve 212 can ensure the initial positioning of the support frame 203 and the fan-shaped claws, and also ensure that the support frame 203 used for initial positioning can move under the pulling force of the clamping cylinder 209 and move toward the workpiece 10, thus achieving double-sided clamping of the workpiece 10.

[0044] A vision unit 7 is mounted on the support 6. The projection of the vision unit 7 is located at the center of the turntable 1. The vision unit 7 captures an image to obtain the center coordinates of the current workpiece 10 and compares them with the center coordinates of the turntable 1 to calculate the offset. The vision unit stores this offset value and sends it to the host computer or PLC. The host computer or PLC calculates the compensation amount of the servo motor based on the X and Y axis offsets, and then controls the servo motor 4 to make precise position adjustments to ensure that the workpiece 10 is centered.

[0045] Please see Figure 8 The hydraulic module 9 includes a hydraulic station, which is connected to a rotary distributor via an oil station distributor. The oil station distributor divides the hydraulic oil into multiple paths. The control panel controls the on / off state of each oil path. Each oil path flows out of the rotary distributor and then passes through the clamp distributor, so that the hydraulic oil flows to the clamping cylinders 209 and locking cylinders 210 on each set of flexible grippers 2.

[0046] Please see Figure 4 and Figure 7 Because the lower surface of the workpiece may not be flat enough, and some parts may be suspended, the workpiece 10 may experience axial runout when subjected to downward cutting force. Therefore, one of the sector claws is provided with at least two sets of auxiliary supports 8. The auxiliary supports 8 include a horizontal pressure bar 801, a movable sleeve 803, and a vertical support column 805. One end of the movable sleeve 803 is connected to the horizontal pressure bar 801 via a front spring 802, and the other end is connected to the sector claw via a rear spring 804. The sector claw is provided with a groove corresponding to the auxiliary support 8. The top of the movable sleeve 803 is provided with an inclined surface 806. 6 is slidably connected to the bottom of the support column 805. Both the support column 805 and the horizontal pressure bar 801 are provided with anti-disengagement mechanisms to prevent the horizontal pressure bar 801 and the support column 805 from disengaging from the groove. The inclined angle of the inclined surface 806 is less than or equal to the friction angle. For example, in the embodiment, the coefficient of friction between the support column 805 and the movable sleeve 803 is 0.15, so the inclined angle is less than or equal to 8.5 degrees. The horizontal pressure bar 801 faces another fan-shaped claw in the same group. When the two fan-shaped claws clamp the workpiece 10, the horizontal pressure bar 801 is pressed in deep enough, and the support column 805 abuts against the lower surface of the workpiece 10.

[0047] When the two sets of fan-shaped jaws clamp the workpiece 10, the horizontal pressure bar 801 is compressed inward, and the force is applied to the moving sleeve 803 through the front spring 802. The movement of the moving sleeve 803 causes the support column 805 to move upward. After the support column 805 presses against the lower surface of the workpiece 10, the moving sleeve 803 stops moving, and the front spring 802 is further compressed to accommodate the further retraction of the horizontal pressure bar 801. The fit between the moving sleeve 803 and the support column 805 has a self-locking function, which can limit the retraction of the support column 805. If the lower surface of the workpiece 10 is suspended, the support column 805 can provide support from below. When it receives a downward cutting force, it can also offset the cutting force and prevent the workpiece 10 from axially running.

[0048] Please see Figures 3-5 To facilitate the adjustment of the relative position between the fan-shaped claw and the support frame 203, the support frame 203 is connected to the fan-shaped claw via a transition plate 204. The transition plate 204 is fixedly connected to the support frame 203 via bolts. The surfaces of the transition plate 204 and the fan-shaped claw are provided with triangular toothed grooves 211. The fan-shaped claw is provided with a waist hole 207. The bolts pass through the waist hole 207 and the transition plate 204 to press the fan-shaped claw tightly onto the transition plate 204. The triangular toothed grooves 211 on the fan-shaped claw and the transition plate 204 mesh with each other to prevent the fan-shaped claw from sliding laterally. At the same time, to prevent the fan-shaped claw from sliding longitudinally, a flat key 213 is also provided between the fan-shaped claw and the transition plate 204. The orientation of the flat key 213 and the triangular toothed groove 211 is perpendicular to each other.

[0049] In Example 2, compared to Example 1, two fan-shaped claws move towards the workpiece 10 to clamp it. However, the clamping process does not allow for adjustment of the workpiece 10's position or angle. Since the fan-shaped claws always face the center of the turntable 1, after the workpiece 10 is placed, its initial position may be off-center relative to the turntable 1, causing the fan-shaped claws to deviate from the center of the workpiece 10. This means the fan-shaped claws are essentially tilted relative to the workpiece 10. When the fan-shaped claws move radially and contact the workpiece 10, one side of the claw contacts the workpiece 10 first. Therefore, the fan-shaped claws may clamp the workpiece 10 using a point clamping method. When adjusting the position of the workpiece 10, the clamping position may experience excessive force concentration, easily causing deformation of the workpiece 10. Therefore, Example 2, based on Example 1, replaces the fan-shaped claws of the adjusting clamp in Example 1 with an adjustable fan-shaped claw 208, or simply replaces the inner fan-shaped claw 206 or the outer fan-shaped claw 205. Please refer to [link to example]. Figures 9-13The adjustable sector claw 208 includes a base plate 2081 fixedly connected to a transition plate 204. The base plate 2081 has a side baffle 2082 on its outer side, the outer side referring to the side away from the other sector claw. A sector plate 2084 is connected to the middle of the side baffle 2082 via a hinge block 2083. The sector plate 2084 is a sector claw with a sector-shaped step. The outer side of the sector plate 2084 and the side baffle 2082 are arched together, leaving a gap. The gap is filled with a highly elastic elastic element 2085, which can be made of polyester fiber material. When one side of 208 contacts the workpiece 10 first, under the elastic action of the elastic element 2085, the sector plate 2084 can rotate along the side wall of the workpiece 10 until the sector plate 2084 is completely in contact with the side wall of the workpiece 10. Furthermore, since the middle position of the sector plate 2084 is connected to the side baffle 2082 through the hinge block 2083, the position of its middle part relative to the adjustable sector claw 208 remains unchanged, and it has consistency when resetting. When clamping the workpiece 10, it can ensure that one or both sides of the workpiece 10 are in surface contact, increasing the force-bearing area and reducing the risk of deformation of the workpiece 10.

[0050] When the adjustable sector claw 208 replaces only one set of sector claws, the bottom of the adjustable sector claw 208 is higher than the bottom of the other sector claw and the bottom of the sector claw on the positioning claw. The bottom refers to the top of the lower step of the sector claw. The auxiliary support 8 is installed on the other sector claw. When the workpiece 10 is placed, the adjustable sector claw 208 provides initial support. When the adjusting clamp moves the workpiece 10, there is no additional resistance between the fixed clamp and the workpiece 10. After the workpiece 10 is clamped, the auxiliary support 8 on the positioning claw and the adjusting claw provides auxiliary support to prevent the workpiece 10 from axially shaking.

[0051] After the workpiece 10 is placed, its gravity acts directly on the bottom of the sector claw. During movement, significant friction occurs, which can damage the bottom of the claw, causing wear. Uneven wear among the sector claws may lead to workpiece 10 tilting, thus reducing clamping accuracy. The bottom of the sector plate 2084 is provided with several ball bearings 2088. In this embodiment, two sets of ball bearings 2088 are provided, located on opposite sides of the sector plate 2084. The space on the sides is relatively large. 4. A sliding plate 2089 is movably connected via a ball bearing 2088. The sliding plate 2089 is fixedly connected to the support base plate 2086 by bolts. An elastic band 2087 is provided between the sector plate 2084 and the sliding plate 2089. The elasticity of the elastic band 2087 keeps the support base plate 2086 reset and centered. When the workpiece 10 is placed, the support base plate 2086 remains in close contact with the lower surface of the workpiece 10 when the sector claws move, and there is no relative movement between them, reducing wear and ensuring the flatness of the bottom of each sector claw.

[0052] Example 3: A method for using a flexible fixture suitable for machining large-diameter thin circular rings, comprising the following steps:

[0053] S1. The locking cylinder 210 is adjusted to the retracted state. First, the position of the fixing clamp is adjusted by adjusting bolt 3, and then the position of the adjusting clamp is adjusted by servo motor 4 so that the position and spacing of the fan-shaped claws on each set of flexible claws 2 are adapted to the contour of the workpiece 10. Under the premise of meeting the loading accuracy of workpiece 10, workpiece 10 can be easily inserted between two fan-shaped claws and supported by the bottom of the fan-shaped claws.

[0054] S2. Adjust the clamping cylinder 209 to the extended state and place the workpiece 10;

[0055] S3. Adjust the clamping cylinder 209 on the adjusting clamp to the retracted state, and the adjusting clamp clamps the workpiece 10.

[0056] S4. The vision unit 7 captures an image to obtain the coordinates of the center point of the current workpiece 10 and compares it with the center coordinates of the turntable 1 to calculate the offset. The vision unit stores the offset value and sends it to the host computer or PLC. The host computer or PLC calculates the compensation amount of the servo motor based on the X and Y axis offsets, and then adjusts the position of each servo motor 4 to ensure that the workpiece 10 can be centered.

[0057] S5. The clamping cylinder 209 on the fixed clamp is adjusted to the retracted state, and the clamping clamp clamps the workpiece 10.

[0058] S6. Each locking cylinder 210 is adjusted to the extended state to lock the position of the fixing clamp and the adjusting clamp.

[0059] S7. Begin machining, such as chamfering the inner and outer rings;

[0060] S8. Each locking cylinder 210 is adjusted to the retracted state, and each clamping cylinder 209 is adjusted to the extended state. The material is unloaded, completing the processing of one workpiece, and the clamping of the next workpiece begins.

[0061] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A flexible fixture suitable for machining large-diameter thin circular ring parts, comprising a turntable (1) and a support (6), wherein the support (6) is connected to a vision unit (7) for monitoring the center coordinates of a workpiece (10), characterized in that: The turntable (1) is provided with at least six sets of flexible grippers (2) evenly distributed along the circumference, of which three sets of flexible grippers (2) are adjustment grippers and the rest are fixed grippers, and the included angle between the two sets of adjustment grippers is 120 degrees. The flexible gripper (2) includes an assembly (201) fixedly connected to the turntable (1) and equipped with a guide rail (202). Two sets of radially movable support frames (203) are movably connected to the guide rail (202). Both sets of support frames (203) are provided with fan-shaped claws with fan-shaped steps. A clamping cylinder (209) is provided between the two sets of support frames (203). A locking cylinder (210) is provided on the side wall of the support frame (203). The locking cylinder (210) extends and presses against the assembly (201) to lock the position of the support frame (203). The support frame (203) on the adjustment clamp is connected to the servo motor (4) through the lead screw pair (5). The servo motor (4) adjusts the position of the adjustment clamp according to the coordinate information so that the workpiece (10) is centered. One support frame (203) on the adjusting clamp is connected to the lead screw pair (5) through an elastic sleeve (212), and the servo motor (4) is connected to the lead screw pair (5) through a nut. One support frame (203) on the fixed clamp is connected to the assembly frame (201) through an adjusting bolt (3), and the adjusting bolt (3) is connected to the support frame (203) through an elastic sleeve (212). At least two sets of auxiliary supports (8) are provided in one of the fan-shaped claws of the flexible gripper (2). The auxiliary support (8) includes a horizontal pressure bar (801), a movable sleeve (803), and a vertical support column (805). One end of the movable sleeve (803) is connected to the horizontal pressure bar (801) through a front spring (802). The other end is connected to the fan-shaped claw via a rear spring (804). The fan-shaped claw has a groove corresponding to the auxiliary support (8). The top of the movable sleeve (803) has an inclined surface (806). The inclined surface (806) is slidably connected to the bottom of the support column (805). The inclined angle of the inclined surface (806) is less than or equal to the friction angle. The support frame (203) is connected to the fan-shaped claw via a transition plate (204). The transition plate (204) is fixedly connected to the support frame (203) via bolts. The surfaces of the transition plate (204) and the fan-shaped claw are provided with triangular tooth grooves (211). The fan-shaped claw has a waist hole (207). The bolt passes through the waist hole (207) and the transition plate (204) to press the fan-shaped claw tightly onto the transition plate. On 204), a flat key (213) is also provided between the fan-shaped claw and the transition plate (204). The orientation of the flat key (213) and the triangular tooth groove (211) is perpendicular to each other. In each set of adjustment clips, at least one fan-shaped claw is an adjustable fan-shaped claw (208). The adjustable fan-shaped claw (208) includes a base plate (2081) fixedly connected to the transition plate (204). The outer side of the base plate (2081) has a side baffle (2082). The middle part of the side baffle (2082) is connected to a fan-shaped plate (2084) through a hinge block (2083). The outer side of the fan-shaped plate (2084) is arched with the side baffle (2082), and there is a gap between them. The gap is filled with an elastic element (2085). The adjustment clamp is provided with an adjustable fan-shaped claw (208). The bottom of the adjustable fan-shaped claw (208) is higher than the bottom of the other fan-shaped claw and the fan-shaped claw on the positioning claw. The auxiliary support (8) in the adjustment clamp is installed on the other fan-shaped claw. The bottom of the fan-shaped plate (2084) is provided with several balls (2088). The fan-shaped plate (2084) is movably connected to a sliding plate (2089) through the balls (2088). The sliding plate (2089) is fixedly connected to the support base plate (2086) by bolts. An elastic band (2087) is provided between the fan-shaped plate (2084) and the sliding plate (2089). The elasticity of the elastic band (2087) makes the support base plate (2086) return to the center.

2. The flexible fixture for machining large-diameter thin circular rings according to claim 1, characterized in that, The two sets of fan-shaped claws are an inner fan-shaped claw (206) and an outer fan-shaped claw (205), and both the inner fan-shaped claw (206) and the outer fan-shaped claw (205) are fixedly connected to the support frame (203).

3. A method for using a flexible fixture suitable for machining large-diameter thin circular ring parts, characterized in that, The workpiece (10) is fixed using a flexible fixture suitable for machining large-diameter thin circular rings as described in claim 1 or 2.

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