Multi-point clamping fixture for sheet metal parts and method of use

Abstract

The application relates to a thin plate piece multi-point clamping fixture and an application method thereof, and relates to the technical field of fixtures. The thin plate piece multi-point clamping fixture comprises a work platform and a clamping unit. The work platform comprises a horizontal base plate. The number of the clamping units is consistent with and one-to-one corresponds to the number of strip-shaped orifices of the horizontal base plate. The shell of the clamping unit is fixedly connected to the lower end of the horizontal base plate and is located at the corresponding strip-shaped orifice. The strip-shaped orifice on the horizontal base plate is arranged in vertical opposition to the strip-shaped opening of the corresponding clamping unit. A kind of thin-walled ring piece end face edge chamfering method is based on a thin-walled ring piece chamfering device and a thin plate piece multi-point clamping fixture. The steps are as follows: 1, clamping the workpiece to be processed; 2, obtaining a machining track; 3, polishing while actively avoiding. The application can meet the clamping and fixing requirements of the chamfering process of the thin-walled ring piece (especially the high-voltage power transformation electrical insulation piece), and provides necessary prerequisites and structural support for the automatic processing scheme of the chamfering process.

Description

Technical Field

[0001] This invention relates to the field of clamping technology, and in particular to a multi-point clamping fixture for thin plates and its application method. Background Technology

[0002] Thin-walled ring components have wide applications in aerospace, automotive, and power transmission equipment. High-voltage transformer insulation components are a typical example of large-sized thin-walled ring components, with outer diameters reaching 1-2m. After the end face machining process is completed, there are still many burrs and sharp edges at the edges (inner hole edge and outer circle edge), which require chamfering.

[0003] In relevant enterprises, the chamfering of high-voltage transformer insulation components is mainly done manually, which is inefficient and the dust generated during grinding is dispersed in the air, causing significant harm to the health of personnel.

[0004] In summary, relevant companies are preparing to develop an automated processing solution for the chamfering process of high-voltage transformer insulation components. The difficulty in developing the solution lies in the fixture design, mainly in the following aspects: 1. The insulation components have low rigidity, requiring a good support and fixing structure; 2. Interference with the chamfering tool should be avoided. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a multi-point clamping fixture for thin plate parts and its application method. It can meet the clamping and fixing requirements of the chamfering process of thin-walled ring parts (especially high-voltage transformer electrical insulation parts), and provides the necessary prerequisites and structural support for the automated processing scheme of the chamfering process.

[0006] The technical solution of the present invention is: a multi-point clamping fixture for thin plates, comprising a working platform and a clamping unit; The working platform includes a horizontal substrate; the horizontal substrate has a plurality of strip-shaped openings evenly distributed in a ring, the smallest circumcircle encompassing all the strip-shaped openings is S, and the extension direction of all the strip-shaped openings passes through the center of the smallest circumcircle S; the end of the strip-shaped opening that is closer to the center of the smallest circumcircle S is the inner end, and the end of the strip-shaped opening that is farther away from the center of the smallest circumcircle S is the outer end. The clamping unit includes a housing, a linear motion drive assembly, a wedge, a servo motor, a cantilever, a cylinder, and a pressure plate. The housing has an internal cavity, and a strip-shaped opening at its upper end connects to this cavity. The linear motion drive assembly is located within the housing cavity and connected to the wedge, driving the wedge to reciprocate linearly along the strip-shaped opening. The upper end of the wedge has a guide slope and a clamping plane sequentially from front to rear. The guide slope has a low end and a high end, with the high end connecting to the clamping plane. The wedge is located within the strip-shaped opening of the housing, with the high end of its guide slope extending beyond the top of the opening. The servo motor is directly or indirectly fixedly connected to the rear side wall of the wedge, with its shaft extending vertically upwards. The rear end of the cantilever is fixedly connected to the servo motor's shaft, and the front end of the cantilever... The end extends horizontally; the cylinder is fixedly connected to the front end of the cantilever, and its piston rod extends vertically downward; the pressure plate is fixedly connected to the piston rod end of the cylinder, and it moves vertically up and down under the direct drive of the cylinder, and moves horizontally in a circular motion under the indirect drive of the servo motor. The path of its horizontal circular motion passes directly above the clamping plane of the wedge; the number of clamping units is consistent with the number of strip holes on the horizontal base plate and corresponds one-to-one. The housing of the clamping unit is fixedly connected to the lower end of the horizontal base plate and located at the corresponding strip hole. The strip holes on the horizontal base plate and the strip openings of the corresponding clamping units are arranged vertically opposite each other. The wedge of the clamping unit extends out above the horizontal base plate through the strip hole, and the lower end of the guide slope of the wedge is lower than the upper surface of the horizontal base plate.

[0007] A further technical solution of the present invention is as follows: the shell includes a lower main body and an upper frame connected to the upper end of the lower main body; both the lower main body and the upper frame are strip-shaped components, the upper end of the lower main body is provided with an opening, and the upper frame is provided with connecting ears at the four corners; the inner cavity is located inside the lower main body, and the strip-shaped opening is provided on the upper frame; the upper frame is fixedly connected to the outer side wall of the lower main body through four connecting ears; when the upper frame and the lower main body are connected to form a shell, the strip-shaped opening of the upper frame is located directly above the opening of the lower main body, forming a hollow area between the upper end face of the lower main body and the lower end face of the upper frame.

[0008] A further technical solution of the present invention is as follows: the linear motion drive assembly includes a lead screw, a bearing seat, a nut, a guide rail, a slider, a base plate, and a motor; both ends of the lead screw are rotatably mounted on the bearing seats and arranged parallel to the strip-shaped opening of the housing, and the two bearing seats are fixedly mounted in the inner cavity of the housing; the nut is threadedly connected to the lead screw and fixedly connected to the bottom surface of the wedge block; two guide rails are fixedly mounted on both sides of the open opening of the lower main body of the housing, and two sets of sliders are slidably mounted on the two guide rails; the base plate is fixedly mounted on the upper end of the two sets of sliders and fixedly connected to the bottom surface of the servo motor; the two guide rails, the two sets of sliders, and the base plate are all located in the hollow area between the lower main body and the upper frame; the motor is fixedly mounted in the inner cavity of the housing and connected to one end of the lead screw through a coupling.

[0009] A further technical solution of the present invention is as follows: the clamping unit further includes a cable constraint follower assembly; the cable constraint follower assembly is located on one side outside the housing; the cable constraint follower assembly includes a cable chain, an upper fixing plate, and a lower fixing plate; the cable chain is formed by multiple chain links hinged sequentially to form a linear flexible body, the chain links at both ends of the cable chain are defined as a front chain link and a rear chain link, respectively, and the cable chain has a cable channel for the cable to pass through, the front chain link has an entrance connected to the cable channel, and the rear chain link has an exit connected to the cable channel; the front chain link is fixedly connected to one side of the base plate by the upper fixing plate, and the rear chain link is fixedly connected to the side wall of the lower main body of the housing by the lower fixing plate; the cable chain and the cable channel inside it adaptably deform as the base plate moves, and all cables connected to the servo motor enter the cable channel through the entrance and exit the cable channel through the exit.

[0010] A further technical solution of the present invention is: the clamping unit further includes a bellows dust cover; the bellows dust cover is a rectangular sheet-like component with extensible and deformable characteristics, and there are two bellows dust covers. One end of the two bellows dust covers is fixedly connected to the lower end of the wedge block and the lower end of the base plate, respectively, and the other end of the two bellows dust covers is fixedly connected to the upper end of the two shaft seats, thereby jointly shielding the lead screw; the two bellows dust covers adaptably extend or shorten as the nut moves on the lead screw.

[0011] The technical solution of the present invention is: a method for chamfering the edge of the end face of a thin-walled annular part, based on a chamfering device for a thin-walled annular part and a multi-point clamping fixture for thin-plate parts; A thin-walled annular chamfering device includes a base, an industrial robotic arm, a floating grinding head, a gantry crane, and a 3D line scan camera. The base is fixedly installed on the ground. The industrial robotic arm is located on the upper end of a horizontal substrate, with a connecting end and a clamping end at its two ends. The connecting end is fixedly installed on the upper end of the base, and the movement range of the clamping end covers the upper area of ​​the horizontal substrate. The floating grinding head is fixedly installed on the clamping end of the industrial robotic arm. The 3D line scan camera is installed on the gantry crane and is moved by the gantry crane. Its scanning field of view within its movement range covers the upper area of ​​the horizontal substrate. Before executing the method, the multi-point clamping fixture for thin sheet metal is in the following initial state: ①. Under the drive of the corresponding linear motion drive component, the wedges in each clamping unit move to the limit position along the corresponding strip orifice, thereby maximizing the size of the maximum inscribed circle R of all wedges; ②. The cylinders and pressure plates in each clamping unit are driven by the corresponding servo motors and rotated by the cantilever to the outer side of the vertically above region of the maximum inscribed circle R; The steps are as follows: S01. Clamping the workpiece to be processed: a. Placement: Place the thin-walled annular part to be processed between all the wedges on the upper surface of the horizontal substrate, at which time the thin-walled annular part is located in the largest inscribed circle R; b. Positioning: The motors of all clamping units start synchronously, driving all wedges to move along the corresponding strip-shaped openings and toward the inner end of the strip-shaped openings, thereby gradually reducing the size of the maximum inscribed circle R until the guide slope of all wedges contacts the lower outer edge of the thin-walled annular part. c. Lifting: All wedges continue to move along the corresponding strip orifice and toward the inner end of the strip orifice. Through the common guidance of the guide slope of all wedges, the thin-walled annular part is lifted to the clamping plane of all wedges. At this time, the lower end face of the thin-walled annular part is supported by the clamping plane of all wedges. d. Clamping: The servo motors of all clamping units are activated, driving the pressure plates of all clamping units to rotate directly above the upper end face of the thin-walled annular part. Then, the piston rods of the cylinders of all clamping units extend, driving the corresponding pressure plates to move downward and finally press against the upper end face of the thin-walled annular part. In this step, the height of the thin-walled annular component relative to the upper surface of the horizontal substrate is sufficient to meet the required clearance height when the floating grinding head grinds the edge of the end face of the thin-walled annular component. In this step, the pressure plates of all clamping units are evenly distributed in a ring and pressed against the upper end face of the thin-walled ring component. S02, Obtain the processing trajectory: Based on the drawing (theoretical size parameters) of the thin-walled ring part to be processed and the 3D line scan camera vision recognition technology, obtain the grinding trajectory of the target thin-walled ring part (i.e. the motion trajectory of the industrial robotic arm). S03, chamfering while actively avoiding obstacles: a. Identify the nearest clamping unit: The industrial robotic arm controls the floating grinding head to perform grinding according to the grinding trajectory. During the grinding process, the 3D line scan camera identifies in real time the nearest clamping unit along the grinding trajectory at the current grinding position. b. Clamping unit releases clamping: When the nearest clamping unit is detected, the piston rod of the cylinder of the clamping unit retracts to release the clamping unit from the pressing state on the upper surface of the thin-walled annular part. c. Clamping unit rotation avoidance: The servo motor of the clamping unit is activated, driving the cantilever to rotate, which in turn drives the cylinder and pressure plate to rotate to the outside of the vertically above area of ​​the maximum inscribed circle R, thereby avoiding interference between the clamping unit and the grinding trajectory. d. Clamping unit rotation reset: When it is detected that the floating grinding head has passed through the area of ​​the clamping unit that rotates to avoid the grinding head along the grinding trajectory, the servo motor of the clamping unit is activated, driving the cantilever to rotate, which in turn drives the cylinder and pressure plate to rotate directly above the upper surface of the thin-walled annular part. e. Clamping unit resumes clamping: Then the piston rod of the cylinder of the clamping unit extends, driving the pressure plate to move downward and finally press against the upper end surface of the thin-walled annular part, thereby restoring the clamping unit to the pressing state of the upper surface of the thin-walled annular part. f. Complete the chamfering process: Repeat the above steps a and e until the floating grinding head reaches the end of the grinding trajectory and completes the chamfering process of the thin-walled ring part.

[0012] In this step, at most one clamping unit is in a rotating and avoiding state at any given time, while the other clamping units remain in a state of clamping the thin-walled annular part.

[0013] Compared with the prior art, the present invention has the following advantages: 1. It provides a multi-point clamping fixture for thin plates, which can meet the clamping and fixing requirements of the chamfering process of thin plates (for example, in Embodiment 1, the high voltage transformer insulation component is a typical thin-walled ring component), and provides the necessary prerequisites and structural support for the automated processing scheme of the chamfering process.

[0014] 2. The multi-point clamping fixture for thin sheet metal adopts a ring-shaped, evenly distributed multi-point clamping scheme. Its advantages are mainly reflected in the following aspects: Ⅰ. Stress Dispersion: The ring-shaped, evenly distributed multi-point clamping disperses the clamping force to more contact points, resulting in relatively smaller forces at each point. This reduces stress concentration at individual points and lowers the risk of workpiece breakage due to excessive local stress. Ⅱ. Easy Deformation Control: Thin-walled ring-shaped parts are prone to elastic deformation during clamping. If there are too few clamping points, the workpiece may develop depressions or protrusions between adjacent clamping points. Multi-point clamping provides more even support, maintaining the workpiece's shape stability. Ⅲ. Vibration Suppression: During grinding, cutting forces cause workpiece vibration. The multi-point clamping scheme increases the contact points between the fixture and the workpiece, improving the overall system rigidity and reducing vibration amplitude. This is beneficial for maintaining machining quality and extending tool life. IV. Each clamping unit can achieve both coordinated linkage and individual control. Furthermore, within a single clamping unit, its clamping structure and avoidance structure can also achieve coordinated linkage or individual control, thereby greatly expanding the applicability of the fixture and enabling it to adapt to various regular or irregular shaped thin plates.

[0015] The multi-point clamping fixture for thin sheet metal employs a multi-point clamping scheme that differs from existing multi-point clamping schemes in the following main aspects: Ⅰ. Lifting before clamping: The workpiece is lifted to the clamping plane by the guiding slope of the wedge blocks, thus creating a clearance height between the lower surface of the workpiece and the upper surface of the horizontal base plate. This meets the clearance height required when the floating grinding head grinds the edge of the thin-walled annular part's end face. Ⅱ. The clamping unit has a rotation avoidance function. During chamfering, the clamping unit on the grinding trajectory rotates sequentially to avoid the floating grinding head (automatically resetting and resuming clamping after avoiding the head). The floating grinding head can complete the chamfering operation of the workpiece's end face edge in one go according to the predetermined grinding trajectory, improving chamfering efficiency.

[0016] 3. It provides a method for chamfering the end face edge of thin-walled annular parts, realizing the automated processing of chamfering of thin-walled annular parts (especially high-voltage transformer electrical insulation parts). Its core innovations are: Ⅰ. The workpiece is first raised and then clamped to meet the required clearance height for grinding; Ⅱ. The tool is automatically avoided during the chamfering process (automatically reset and resume clamping after avoiding the tool), and the tool can complete the chamfering operation of the end face edge of the workpiece in one go, improving the chamfering efficiency.

[0017] The present invention will be further described below with reference to the figures and embodiments. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the clamping unit from a first perspective. Figure 3 This is a schematic diagram of the clamping unit from a second perspective. Figure 4 This is a schematic diagram of the internal structure of the clamping unit; Figure 5 The state diagram for step b of S01; Figure 6 This is the state diagram for step c of S03.

[0019] Legend: Horizontal base plate 1; strip-shaped opening 11; housing 2; strip-shaped opening 20; lower main body 21; upper frame 22; connecting ear 221; hollow area 23; lead screw 31, shaft seat 32; nut 33; guide rail 34; slider 35; base plate 36; motor 37; wedge block 4; guide slope 41; clamping plane 42; servo motor 51; cantilever 52; cylinder 61; pressure plate 62; drag chain 71; inlet 711; outlet 712; upper fixed plate 72; lower fixed plate 73; accordion dust cover 8; thin-walled ring part 100. Detailed Implementation Example 1

[0020] like Figure 1-4 As shown, the multi-point clamping fixture for thin sheet metal includes a work platform and a clamping unit.

[0021] The working platform includes a horizontal substrate 1. The horizontal substrate 1 has a plurality of annularly distributed strip-shaped openings 11. The smallest circumscribed circle encompassing all the strip-shaped openings 11 is denoted by S, and the extension direction of all the strip-shaped openings 11 passes through the center of the smallest circumscribed circle S. The end of a strip-shaped opening 11 closest to the center of the smallest circumscribed circle S is the inner end, and the end of a strip-shaped opening 11 furthest from the center of the smallest circumscribed circle S is the outer end.

[0022] The clamping unit includes a housing 2, a linear motion drive assembly, a wedge 4, a servo motor 51, a cantilever 52, a cylinder 61, and a pressure plate 62. The housing 2 has an internal cavity, and its upper end has a strip-shaped opening 20 connecting to this cavity. The linear motion drive assembly is located within the cavity of the housing 2 and connected to the wedge 4, driving the wedge 4 to reciprocate linearly along the strip-shaped opening 20 of the housing 2. The upper end of the wedge 4 has a guide slope 41 and a clamping plane 42 arranged sequentially from front to rear. The guide slope 41 has a low end and a high end, with the high end connecting to the clamping plane 42. The wedge 4 is located within the strip-shaped opening 20 of the housing 2, with the high end of its guide slope 41 extending beyond the upper end of the opening 20, thus partially or completely exposing the guide slope 41 above the opening 20. The servo motor 51 is directly or indirectly fixedly connected to the rear side wall of the wedge 4, with its shaft extending vertically upwards. The rear end of the cantilever 52 is fixedly connected to the shaft of the servo motor 51, and the front end of the cantilever 52 extends horizontally. The cylinder 61 is fixedly connected to the front end of the cantilever 52, and its piston rod extends vertically downward. The pressure plate 62 is fixedly connected to the end of the piston rod of the cylinder 61. It performs vertical lifting and lowering motion under the direct drive of the cylinder, and performs horizontal circular motion under the indirect drive of the servo motor 51. The path of its horizontal circular motion passes directly above the clamping plane 42 of the wedge block 4.

[0023] The number of clamping units is consistent with the number of strip openings 11 on the horizontal substrate 1 and corresponds one-to-one. The housing 2 of the clamping unit is fixedly connected to the lower end of the horizontal substrate 1 and located at the corresponding strip opening 11. The strip openings 11 on the horizontal substrate 1 and the strip openings 20 of the corresponding clamping units are arranged vertically opposite each other. The wedge 4 of the clamping unit extends out above the horizontal substrate 1 through the strip opening 11. The lower end of the guide slope 41 of the wedge 4 is lower than the upper surface of the horizontal substrate 1, thereby avoiding the formation of a step between the lower end of the guide slope 41 and the upper surface of the horizontal substrate 1.

[0024] Preferably, the housing 2 includes a lower body 21 and an upper frame 22 connected to the upper end of the lower body 21. Both the lower body 21 and the upper frame 22 are strip-shaped components. The upper end of the lower body 21 has an opening, and the upper frame 22 has connecting ears 221 at its four corners. The inner cavity is located inside the lower body 21, and the strip-shaped opening 20 is located on the upper frame 22. The upper frame 22 is fixedly connected to the outer side wall of the lower body 21 through the four connecting ears 221. When the upper frame 22 and the lower body 21 are connected to form the housing, the strip-shaped opening 20 of the upper frame 22 is located directly above the opening of the lower body 21, forming a hollow area 23 between the upper end face of the lower body 21 and the lower end face of the upper frame 22. The hollow area 23 is the installation area for some components in the linear motion drive assembly.

[0025] Preferably, the linear motion drive assembly includes a lead screw 31, a bearing seat 32, a nut 33, a guide rail 34, a slider 35, a base plate 36, and a motor 37. The two ends of the lead screw 31 are rotatably mounted on the bearing seats 32 and arranged parallel to the strip opening 20 of the housing 2. The two bearing seats 32 are fixedly mounted inside the housing 2. The nut 33 is threaded onto the lead screw 31 and fixedly connected to the bottom surface of the wedge block 4. Two guide rails 34 are fixedly mounted on both sides of the opening of the lower main body 21 of the housing 2, and two sets of sliders 35 are slidably mounted on the two guide rails 34, each set of sliders 35 including one or more sliders 35. The base plate 36 is fixedly mounted on the upper ends of the two sets of sliders 35 and fixedly connected to the bottom surface of the servo motor 4. The two guide rails 34, the two sets of sliders 35, and the base plate 36 are all located in the hollow area 23 between the lower main body 21 and the upper frame 22. The motor 37 is fixedly installed in the inner cavity of the housing 2 and connected to one end of the lead screw 31 through a coupling. It is used to drive the nut 33 to move back and forth linearly along the lead screw, thereby driving the wedge block 4, the servo motor 51, the cantilever 52, the cylinder 61 and the pressure plate 62 to move back and forth linearly.

[0026] Preferably, the clamping unit further includes a cable constraint follower assembly. The cable constraint follower assembly is located on one side of the exterior of the housing 2. The cable constraint follower assembly includes a cable chain 71, an upper fixing plate 72, and a lower fixing plate 73. The cable chain 71 is a linear flexible body formed by multiple links hinged sequentially. The links at both ends of the cable chain 71 are defined as the front link and the rear link, respectively. The cable chain 71 has a cable channel for cables to pass through. The front link has an inlet 711 connected to the cable channel, and the rear link has an outlet 712 connected to the cable channel. The front link is fixedly connected to one side of the base plate 36 via the upper fixing plate 72, and the rear link is fixedly connected to the side wall of the lower main body 21 of the housing 2 via the lower fixing plate 73. The cable chain 71 and its internal cable channel adaptably to the movement of the base plate 36. All cables connected to the servo motor 51 enter the cable channel through the inlet 711 and exit the cable channel through the outlet 712.

[0027] Preferably, the clamping unit also includes an accordion dust cover 8. The accordion dust cover 8 is a rectangular sheet-like component with expandable and deformable characteristics. Two accordion dust covers 8 are provided; one end of each is fixedly connected to the lower end of the wedge block 4 and the lower end of the base plate 36, respectively, and the other end is fixedly connected to the upper ends of the two bearing seats 32, thus collectively shielding the lead screw 31 and preventing dust from entering it. The two accordion dust covers 8 adaptably extend or shorten as the nut 33 moves on the lead screw 31.

[0028] A method for chamfering the end face edge of a thin-walled annular component, based on a chamfering device for a thin-walled annular component and a multi-point clamping fixture for thin-plate components.

[0029] A thin-walled annular chamfering device includes a base, an industrial robotic arm, a floating grinding head, a gantry crane (not shown in the figure), and a 3D line scan camera (not shown in the figure). The base is fixedly installed on the ground. The industrial robotic arm is located on the upper end of a horizontal substrate 1, with a connecting end and a clamping end at its two ends. The connecting end is fixedly installed on the upper end of the base, and the movement range of the clamping end covers the upper area of ​​the horizontal substrate 1. The floating grinding head is fixedly installed on the clamping end of the industrial robotic arm. The 3D line scan camera is mounted on the gantry crane and moved by the gantry crane; its scanning field of view within its movement range covers the upper area of ​​the horizontal substrate 1.

[0030] Before executing the method, the multi-point clamping fixture for thin sheet metal is in the following initial state: ①. Each wedge 4 in each clamping unit moves to its limit position along the corresponding strip-shaped opening 11 under the drive of the corresponding linear motion drive component, thereby maximizing the size of the maximum inscribed circle R of all wedges 4.

[0031] ②. The cylinders 61 and pressure plates 62 in each clamping unit are driven by the corresponding servo motors 51 and rotated by the cantilever 52 to the outside of the vertically above region of the maximum inscribed circle R.

[0032] like Figure 5-6 As shown, the method steps are as follows: S01. Clamping the workpiece to be processed: a. Placement: Place the thin-walled annular part 100 to be processed between all the wedges 4 on the upper surface of the horizontal substrate 1. At this time, the thin-walled annular part 100 is located in the largest inscribed circle R. b. Positioning: The motors 37 of all clamping units start synchronously, driving all wedges 4 to move along the corresponding strip-shaped openings 11 and toward the inner end of the strip-shaped openings 11, thereby gradually reducing the size of the maximum inscribed circle R until the guide slopes 41 of all wedges 4 contact the lower outer edge of the thin-walled annular part 100. c. Lifting: All wedges 4 continue to move along the corresponding strip-shaped opening 11 and toward the inner end of the strip-shaped opening 11. Through the common guidance of the guide slope 41 of all wedges 4, the thin-walled annular part 100 is lifted onto the clamping plane 42 of all wedges 4. At this time, the lower end face of the thin-walled annular part 100 is supported by the clamping plane 42 of all wedges 4. d. Clamping: The servo motors 51 of all clamping units start simultaneously or in any order, driving the pressure plates 62 of all clamping units to rotate directly above the upper end face of the thin-walled annular part 100. Then, the piston rods of the cylinders 61 of all clamping units extend, driving the corresponding pressure plates 62 to move downward and finally press against the upper end face of the thin-walled annular part 100.

[0033] In this step, the height of the thin-walled annular component 100 relative to the upper surface of the horizontal substrate 1 is such that it satisfies the required clearance height when the floating grinding head grinds the edge of the end face of the thin-walled annular component 100.

[0034] In this step, the pressure plates 62 of all clamping units are evenly distributed in a ring and pressed against the upper end face of the thin-walled annular part 100.

[0035] S02, Obtain the processing trajectory: Based on the drawing (theoretical size parameters) of the thin-walled ring part to be processed and the 3D line scan camera vision recognition technology, obtain the grinding trajectory of the target thin-walled ring part (i.e. the motion trajectory of the industrial robotic arm).

[0036] In this step, the method of obtaining the processing trajectory based on drawings and visual recognition is a mature existing technology. The specific operation process is briefly described as follows: Prerequisites: ①. Set the scanning start point, scanning end point, and edge type (straight edge or curved edge) of the grinding edge of the thin-walled ring part according to the drawing, and generate a scanning path program; ②. Calibrate the 3D line scanning camera and the floating grinding head; ③. Perform coordinate transformation between the workpiece drawing and the industrial robotic arm; Operation process: ①. Manually set the model of the current thin-walled ring part; ②. Call the corresponding scanning path program to scan the grinding edge of the current thin-walled ring part; ③. Fit straight lines and / or arcs according to the scanning data; ④. Generate the actual grinding trajectory according to the fitted data.

[0037] S03, chamfering while actively avoiding obstacles: a. Identify the nearest clamping unit: The industrial robotic arm controls the floating grinding head to perform grinding according to the grinding trajectory. During the grinding process, the 3D line scan camera identifies in real time the nearest clamping unit along the grinding trajectory at the current grinding position. b. Clamping unit releases clamping: When the nearest clamping unit is detected, the piston rod of the cylinder 61 of the clamping unit retracts to release the clamping unit from the pressing state on the upper surface of the thin-walled annular part 100. c. Clamping unit rotation avoidance: The servo motor 51 of the clamping unit is activated, driving the cantilever 52 to rotate, which in turn drives the cylinder 61 and the pressure plate 62 to rotate to the outside of the vertically above area of ​​the maximum inscribed circle R, thereby avoiding interference between the clamping unit and the grinding trajectory. d. Clamping unit rotation reset: When it is detected that the floating grinding head has passed through the area of ​​the clamping unit that rotates to avoid the grinding along the grinding trajectory, the servo motor 51 of the clamping unit is activated, driving the cantilever 52 to rotate, which in turn drives the cylinder 61 and the pressure plate 62 to rotate directly above the upper surface of the thin-walled annular part 100. e. Clamping unit resumes clamping: Then the piston rod of the cylinder 61 of the clamping unit extends, driving the pressure plate 62 to move downward and finally press against the upper end surface of the thin-walled annular part 100, thereby restoring the clamping state of the clamping unit on the upper surface of the thin-walled annular part 100. f. Complete the chamfering process: Repeat the above steps a and e until the floating grinding head reaches the end of the grinding trajectory and completes the chamfering process of the thin-walled ring part.

[0038] In this step, at most one clamping unit is in a rotating and avoiding state at any given time, while the other clamping units remain in a state of clamping the thin-walled annular part.

Claims

1. A multi-point clamping fixture for thin sheet metal parts, characterized by: Includes a working platform and a clamping unit; The working platform includes a horizontal substrate; the horizontal substrate has a plurality of strip-shaped openings evenly distributed in a ring, the smallest circumcircle encompassing all the strip-shaped openings is S, and the extension direction of all the strip-shaped openings passes through the center of the smallest circumcircle S; the end of the strip-shaped opening that is closer to the center of the smallest circumcircle S is the inner end, and the end of the strip-shaped opening that is farther away from the center of the smallest circumcircle S is the outer end. The clamping unit includes a housing, a linear motion drive assembly, a wedge, a servo motor, a cantilever, a cylinder, and a pressure plate. The housing has an internal cavity, and a strip-shaped opening at its upper end connects to this cavity. The linear motion drive assembly is located within the housing cavity and connected to the wedge, driving the wedge to reciprocate linearly along the strip-shaped opening. The upper end of the wedge has a guide slope and a clamping plane sequentially from front to rear. The guide slope has a low end and a high end, with the high end connecting to the clamping plane. The wedge is located within the strip-shaped opening of the housing, with the high end of its guide slope extending beyond the top of the opening. The servo motor is directly or indirectly fixedly connected to the rear side wall of the wedge, with its shaft extending vertically upwards. The rear end of the cantilever is fixedly connected to the servo motor's shaft, and the front end of the cantilever... The end extends horizontally; the cylinder is fixedly connected to the front end of the cantilever, and its piston rod extends vertically downward; the pressure plate is fixedly connected to the piston rod end of the cylinder, and it moves vertically up and down under the direct drive of the cylinder, and moves horizontally in a circular motion under the indirect drive of the servo motor. The path of its horizontal circular motion passes directly above the clamping plane of the wedge; the number of clamping units is consistent with the number of strip holes on the horizontal base plate and corresponds one-to-one. The housing of the clamping unit is fixedly connected to the lower end of the horizontal base plate and located at the corresponding strip hole. The strip holes on the horizontal base plate and the strip openings of the corresponding clamping units are arranged vertically opposite each other. The wedge of the clamping unit extends out above the horizontal base plate through the strip hole, and the lower end of the guide slope of the wedge is lower than the upper surface of the horizontal base plate.

2. The multi-point clamping fixture for thin plates as described in claim 1, characterized in that: The shell includes a lower main body and an upper frame connected to the upper end of the lower main body; both the lower main body and the upper frame are strip-shaped components, the upper end of the lower main body has an opening, and the upper frame has connecting ears at the four corners; the inner cavity is located inside the lower main body, and the strip-shaped opening is located on the upper frame; the upper frame is fixedly connected to the outer side wall of the lower main body through four connecting ears; when the upper frame and the lower main body are connected to form the shell, the strip-shaped opening of the upper frame is located directly above the opening of the lower main body, forming a hollow area between the upper end face of the lower main body and the lower end face of the upper frame.

3. The multi-point clamping fixture for thin plates as described in claim 2, characterized in that: The linear motion drive assembly includes a lead screw, bearings, a nut, guide rails, sliders, a base plate, and a motor. The two ends of the lead screw are rotatably mounted on the bearings and arranged parallel to the strip-shaped opening of the housing. The two bearings are fixedly mounted inside the housing cavity. The nut is threaded onto the lead screw and fixedly connected to the bottom surface of the wedge block. Two guide rails are fixedly mounted on both sides of the open portion of the lower main body of the housing, and two sets of sliders are slidably mounted on the two guide rails. The base plate is fixedly mounted on the upper ends of the two sets of sliders and fixedly connected to the bottom surface of the servo motor. The two guide rails, the two sets of sliders, and the base plate are all located in the hollow area between the lower main body and the upper frame. The motor is fixedly mounted inside the housing cavity and connected to one end of the lead screw via a coupling.

4. The multi-point clamping fixture for thin plates as described in claim 3, characterized in that: The clamping unit also includes a cable constraint follower assembly; the cable constraint follower assembly is located on one side of the outer side of the housing; the cable constraint follower assembly includes a cable chain, an upper fixed plate, and a lower fixed plate; the cable chain is formed by multiple links hinged in sequence to form a linear flexible body, and the links at both ends of the cable chain are defined as the front link and the rear link, respectively. The cable chain has a cable channel for the cable to pass through, the front link has an entrance connected to the cable channel, and the rear link has an exit connected to the cable channel; the front link is fixedly connected to one side of the base plate by the upper fixed plate, and the rear link is fixedly connected to the side wall of the lower main body of the housing by the lower fixed plate; the cable chain and its internal cable channel adaptably to the movement of the base plate, and all cables connected to the servo motor enter the cable channel through the entrance and exit the cable channel through the exit.

5. The multi-point clamping fixture for thin plates as described in claim 4, characterized in that: The clamping unit also includes a bellows dust cover; the bellows dust cover is a rectangular sheet-like component with telescopic deformation characteristics. There are two bellows dust covers. One end of the two bellows dust covers is fixedly connected to the lower end of the wedge block and the lower end of the base plate, respectively. The other end of the two bellows dust covers is fixedly connected to the upper end of the two shaft seats, respectively, so as to jointly cover the lead screw. The two bellows dust covers adaptably to the movement of the nut on the lead screw by extending or shortening.

6. A method for chamfering the end face edge of a thin-walled annular component, based on a chamfering device for a thin-walled annular component and a multi-point clamping fixture for thin-plate components; Its characteristic is: thin walls The ring-shaped chamfering device includes a base, an industrial robotic arm, a floating grinding head, a gantry crane, and a 3D line scan camera. The base is fixedly installed on the ground. The industrial robotic arm is located on the upper part of a horizontal substrate, with a connecting end and a clamping end at its two ends. The connecting end is fixedly installed on the upper part of the base, and the movement range of the clamping end covers the upper area of ​​the horizontal substrate. The floating grinding head is fixedly installed on the clamping end of the industrial robotic arm. The 3D line scan camera is installed on the gantry crane and is moved by the gantry crane. Its scanning field of view within its movement range covers the upper area of ​​the horizontal substrate. Before executing the method, the multi-point clamping fixture for thin sheet metal is in the following initial state: ①. Under the drive of the corresponding linear motion drive component, the wedges in each clamping unit move to the limit position along the corresponding strip orifice, thereby maximizing the size of the maximum inscribed circle R of all wedges; ②. The cylinders and pressure plates in each clamping unit are driven by the corresponding servo motors and rotated by the cantilever to the outer side of the vertically above region of the maximum inscribed circle R; The steps are as follows: S01. Clamping the workpiece to be processed: a. Placement: Place the thin-walled annular part to be processed between all the wedges on the upper surface of the horizontal substrate, at which time the thin-walled annular part is located in the largest inscribed circle R; b. Positioning: The motors of all clamping units start synchronously, driving all wedges to move along the corresponding strip-shaped openings and toward the inner end of the strip-shaped openings, thereby gradually reducing the size of the maximum inscribed circle R until the guide slope of all wedges contacts the lower outer edge of the thin-walled annular part. c. Lifting: All wedges continue to move along the corresponding strip orifice and toward the inner end of the strip orifice. Through the common guidance of the guide slope of all wedges, the thin-walled annular part is lifted to the clamping plane of all wedges. At this time, the lower end face of the thin-walled annular part is supported by the clamping plane of all wedges. d. Clamping: The servo motors of all clamping units are activated, driving the pressure plates of all clamping units to rotate directly above the upper end face of the thin-walled annular part. Then, the piston rods of the cylinders of all clamping units extend, driving the corresponding pressure plates to move downward and finally press against the upper end face of the thin-walled annular part. In this step, the height of the thin-walled annular component relative to the upper surface of the horizontal substrate is sufficient to meet the required clearance height when the floating grinding head grinds the edge of the end face of the thin-walled annular component. In this step, the pressure plates of all clamping units are evenly distributed in a ring and pressed against the upper end face of the thin-walled ring component. S02, Obtain the processing trajectory: Based on the drawing of the thin-walled annular part to be processed and the 3D line scan camera visual recognition technology, obtain the grinding trajectory of the target thin-walled annular part. S03, actively avoids obstacles while polishing: a. Identify the nearest clamping unit: The industrial robotic arm controls the floating grinding head to perform grinding according to the grinding trajectory. During the grinding process, the 3D line scan camera identifies in real time the nearest clamping unit along the grinding trajectory at the current grinding position. b. Clamping unit releases clamping: When the nearest clamping unit is detected, the piston rod of the cylinder of the clamping unit retracts to release the clamping unit from the pressing state on the upper surface of the thin-walled annular part. c. Clamping unit rotation avoidance: The servo motor of the clamping unit is activated, driving the cantilever to rotate, which in turn drives the cylinder and pressure plate to rotate to the outside of the vertically above area of ​​the maximum inscribed circle R, thereby avoiding interference between the clamping unit and the grinding trajectory. d. Clamping unit rotation reset: When it is detected that the floating grinding head has passed through the area of ​​the clamping unit that rotates to avoid the grinding head along the grinding trajectory, the servo motor of the clamping unit is activated, driving the cantilever to rotate, which in turn drives the cylinder and pressure plate to rotate directly above the upper surface of the thin-walled annular part. e. Clamping unit resumes clamping: Then the piston rod of the cylinder of the clamping unit extends, driving the pressure plate to move downward and finally press against the upper end surface of the thin-walled annular part, thereby restoring the clamping unit to the pressing state of the upper surface of the thin-walled annular part. f. Complete the chamfering process: Repeat the above steps a and e until the floating grinding head reaches the end of the grinding trajectory and completes the chamfering process of the thin-walled ring part; In this step, at most one clamping unit is in a rotating and avoiding state at any given time, while the other clamping units remain in a state of clamping the thin-walled annular part.

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