A case study of a process and complete equipment for an eccentric tail tip inner folding edge with an independently servo-driven lifting mechanism.

Abstract

(As shown in Figure 2) Wrinkles and even cracks are easily generated when folding long edges or folding three-layer steel edges, such as those found in kitchenware. Traditional eccentric tail-top structures and processes keep the eccentric wheel stationary. However, the new process of this invention allows the eccentric wheel to move digitally and programmably to the appropriate position at the top of the edge to be folded, and then folds the edge through a three-axis linkage with the folding wheel (X, Z axes). The folding process ensures that the straight cylindrical wall between the eccentric wheel and the folding wheel remains in a clamped and pressed state (the process gap is precisely controllable) until the eccentric wheel and the folding wheel reach their final positions, completing the folding process. Clearly, the new process and equipment offer excellent controllability, the straight cylindrical wall is barely thinned, wrinkles are eliminated, and a downward-sloping folding path can be fitted to complete the inner folding in one go, greatly improving work efficiency.

Description

Technical Field

[0001] In CNC spinning, straight edges are folded internally onto cylindrical shapes. A commonly used eccentric tail jack separates the eccentric wheel from the tail jack, allowing for digitally controlled upward and downward movements driven by a servo motor. This enables precise folding from top to bottom on cylindrical shapes, regardless of the required length (e.g., to fold a 30mm straight edge, the eccentric wheel can rise to a position 10mm or less inside the cylinder, working in conjunction with the folding wheel to fold downwards along the cylinder wall until the desired 30mm length is achieved). This process is characterized by its modular and stable precision, significantly reducing the risk of wall thinning, wrinkling, and cracking during internal folding. Background Technology

[0002] In the field of CNC spinning, the inner folding of straight cylinders can also be achieved through an eccentric tail (but the eccentric wheel and tail structure are fixed). If the folded edge is long, the folding wheel needs to follow multiple cutting paths according to requirements, forcing the straight wall to continuously approach the eccentric wheel and ultimately achieve the desired inner folding effect by adhering to the eccentric wheel. The disadvantage is that excessive back-and-forth cutting (constantly drifting out and returning to the arc path) can cause thinning of the inner folded edge wall, and even wrinkling and cracking. When folding the inner fold of straight cylinders in three-layer steel kitchenware, due to the large differences in the physical properties of different materials, the material will inevitably wrinkle and crack due to excessive force during folding, thus making it impossible to complete the folding process. Summary of the Invention

[0003] Purpose The invention of this process method and equipment aims to utilize an independent eccentric wheel driven by a servo motor as one of the moving axes, which works in conjunction with the X and Z axes of the folding wheel. This allows for a single, downward-sloping linear motion (for the arc edge, a downward-sloping parabolic trajectory) to perfectly and precisely complete the inner folding process without requiring multiple passes.

[0004] II. Technical Solution (Process Method)

[0005] Through (attached) Figure 8(See the schematic diagram of the servo-driven lifting eccentric wheel and tail-end equipment for internal folding.) We can see that: First, the pre-folded straight cylinder is placed into the folding die. The hydraulic tail-end pushes it in, and the small tail-end equipped with this equipment compacts the straight cylinder, causing the machine spindle to rotate. The eccentric wheel rises to the starting position under the drive of the servo motor, and simultaneously the folding wheel is positioned. The eccentric wheel moves downwards at a constant speed according to the given program data (arrow one), while the folding wheel pushes inwards and downwards from the outer wall of the straight cylinder, always maintaining the required folding gap with the eccentric wheel. Its trajectory is fitted as a downward-sloping straight line (arrow two) until the eccentric wheel reaches the termination position, and the internal folding process is successfully completed. Because the inner wall of the straight cylinder is always under the clamping and protective pressure of the lifting eccentric wheel and the folding wheel, all the disadvantages of traditional folding are avoided. (Note: The eccentric wheel with the arc at the end face of the internal folded arc still moves downwards in a straight line, while the movement trajectory of the folding wheel is a fitted downward parabola.) III. Technical Solution (Equipment Structure) As shown in Figure (2), this eccentric tail-top invention device has an eccentric wheel based on servo drive that can perform upward and downward movements. Its structure includes ① a hydraulic tail-top, which has a hydraulic tail-top (18) and a tail-top connecting sleeve (19). ② A "Z"-shaped tail-top device composed of a crossbar, a fixed core rod, and an intermediate fixed plate (see Figure 6) includes a tail-top spindle (1), a small tail-top (2), a fixed crossbar (3), a fixed core rod (4), and an intermediate fixed plate (8). ③ A similarly height-adjustable eccentric wheel structure that passes through the intermediate fixed plate (see Figure 6). Figure 5 The components include an inner eccentric wheel (6), an outer eccentric wheel (7), an eccentric wheel trident tube (5) that can be inserted upwards and slidably fitted to a fixed mandrel, a lead screw connecting ring (9), a lead screw (15), a shaft connector (16), a servo motor (17), and a motor fixing connecting plate (10). Fourth, the more beneficial effects highlighted by the new process methods and supporting equipment design. Wrinkles are easily formed on long, inwardly folded edges, or on the inner edges of three-layer steel used in kitchenware. Traditional eccentric tail-top structures and processes involve a stationary eccentric wheel. The new process, however, allows the eccentric wheel to move digitally and programmably to the appropriate position at the top of the edge to be folded, and then works in servo linkage with the folding wheel. This ensures that the straight cylindrical wall of the eccentric wheel and the folding wheel remains in a clamping and pressing state (with precise and controllable process gaps) until the eccentric wheel reaches its final position, completing the folding process. Clearly, the new process offers better controllability, minimal thinning of the straight cylindrical wall, and no wrinkling. Furthermore, it allows for a perfectly smooth inner fold by fitting a downward-sloping folding path, significantly improving work efficiency. (Note: If there is a special need, due to the advantage that the eccentric wheel and the folding wheel can be linked, the folding process can also be that the eccentric wheel gradually descends in stages, and the folding wheel can be folded and formed several times back and forth. However, its advantage over the traditional process is that the traditional process is to do multiple back and forth empty folding.) Claim 1: A three-axis linkage based on the two axes (X and Z axes) of the servo-driven independently extendable eccentric wheel and tail top equipment and the folding wheel. A process method and equipment case for achieving precision one-time folding, the claim is characterized by including the following steps: Step S1: Loading the straight cylinder. Place the straight cylinder (21) to be folded into the folding straight cylinder cavity (20), and start the program that has been edited by the CNC spinning machine. The whole set of liftable eccentric wheel and tail top equipment (26) will be pushed forward into the straight cylinder cavity (20) under the action of the hydraulic tail top (18) to press the straight cylinder firmly into the cavity. Its hydraulic tail pressure is generally adjusted to between 1.5Mpa and 5Mpa, depending on the size, material characteristics, and thickness of the straight cylinder. Step S2: The spindle (22) of the CNC spinning machine rotates, and the liftable eccentric wheel is positioned. The spindle (22) of the spinning machine drives the folding straight cylinder die (20) connected to it to rotate at a constant speed. The liftable eccentric wheel (6+7) rises under the drive of the servo motor (17) until the required pre-folding starting position. At the same time, the folding wheel (23) reaches the initial folding position under the combined drive of the spinning machine's X-axis (24) and Z-axis (27). The spindle speed is usually 60-350 rpm, and the larger the straight cylinder, the lower the speed. Step S3: Three-axis linkage folding. Through the uniform downward movement of the eccentric wheel (6+7) and the three-axis linkage clamping of the folding wheel (23), a finished inner folded product with precise dimensions and perfect appearance is obtained. The linkage consists of three axes: the X-axis (24), Z-axis (27), and eccentric wheel axis (15) of the spinning machine. The fitting path of the folding wheel is a straight line diagonally downward. The entire folding process is controlled by a pre-edited CNC program. Step S4: Folding completed, product removed. The spindle (22) of the CNC spinning machine stops rotating, and the entire set of lifting eccentric wheels and tail-end equipment (26) is steadily retracted under the drive of the hydraulic tail-end (at which time the program ends), and the finished product after folding is taken out. Attached Figure Description

[0006] Appendix Figure 1Side view of a CNC spinning machine equipped with the device of this invention (liftable eccentric wheel and tail top) Appendix Figure 2 Main sectional view of the equipment (liftable eccentric wheel and tail top) of the present invention with the CNC spinning machine spindle, the bending die, and the straight cylinder to be bent. Appendix Figure 3 Main sectional view of the device of this invention alone. Appendix Figure 4 Exploded view of servo-driven lifting eccentric wheel and tail-top equipment Appendix Figure 5 Side view of the assembly of the servo-driven lifting eccentric wheel and tail-top equipment Appendix Figure 6 Cross-sectional view of the lifting structure and servo component of a servo-driven lifting eccentric wheel and tail-top device. Appendix Figure 7 A cross-sectional view of the fixed "Z"-shaped structure of the small tail top, which is equipped with a servo-driven lifting eccentric wheel and tail top device. Appendix Figure 8 Schematic diagram of servo-driven lifting eccentric wheel and tail-top equipment inner folding edge In the diagram: 1-Small tail jack mandrel; 2-Small tail jack; 3-Fixed crossbar; 4-Fixed mandrel; 5-Eccentric wheel trident tube; 6-Eccentric wheel inner wheel; 7-Eccentric wheel outer wheel; 8-Intermediate fixing plate; 9-Screw connecting ring; 10-Motor fixing connecting plate; 11-Small deep groove ball bearing; 12-Locking nut; 13-Taper bearing; 14-Screw nut; 15-Screw; 16-Shaft connector; 17-Servo motor; 18-Hydraulic tail jack; 19-Hydraulic tail jack connecting sleeve; 20-Folding straight cylinder die; 21-Straight cylinder to be folded; 22-Spinning machine spindle; 23-Folding spinning wheel (Case 1); 24-Spinning machine X-axis; 25-Spinning machine multi-station tool holder; 26-Complete set of liftable eccentric wheel and tail jack equipment; 27-Spinning machine Z-axis. Detailed Implementation

[0007] The specific embodiments of the present invention are described below with reference to the accompanying drawings. This embodiment is implemented based on the existing process and technical solution, and provides a detailed description of the equipment structure, implementation method, and specific operation process. However, the protection range of the servo-driven lifting eccentric wheel and tail top of the present invention is not limited to the following embodiment: Equipment assembly and debugging As shown in the attached figure, the mechatronics equipment assembly of this embodiment includes: ① A straight cylindrical part to be folded internally with a folding die (20). This part is connected to the spindle of the CNC spinning machine through a connecting flange. The concentricity between the die and the spindle is ensured to be within 2 to 6 microns. The gap between the outer wall of the straight cylinder and the die is about 5 to 10 microns, so that it can be freely inserted or removed while ensuring concentricity and tightness. ② A small tail top mandrel (1) is inserted into the mating hole of the fixed crossbar (3), and the screw is tightened from the back. A deep groove ball bearing (11) is fitted into and tightly fitted to the small tail top mandrel (1), and the small tail top (2) is forcefully pushed into the bearing to ensure that the small tail top and the bearing are interference fit and can rotate freely without loosening. ③ An eccentric inner wheel (6) is pressed into tapered bearings (13) at both ends with external force. The two are interference fit. The outer wheel (7) of the eccentric wheel is fitted into the inner wheel (6) with a 3-thread internal sliding fit. After aligning the screw holes, the screw is inserted from the inner wheel end to lock and fix the inner and outer wheels. ④ Insert the inner and outer wheels (6+7) of the eccentric wheel fixed in the previous step into the front end of the eccentric wheel triangular tube (5) with an interference fit. The inner ring of the tapered bearing at the front end of the eccentric wheel presses against the small step of the triangular tube, and the rear end is locked and fixed to the triangular tube with a lock nut (12) (Note: the inner rings of the two tapered bearings are height adjustment washers). ⑤ Press one end of the fixing mandrel (4) tightly into the mating hole of the middle fixing plate (8) and tighten it with a screw. Insert the eccentric wheel triangular tube (5) from the previous step into the fixing mandrel (4) with a 3-5 thread sliding fit. The triangular part of the triangular tube passes through the three mating slots of the middle fixing plate (8) (see Appendix for details). Figure 5The fit is a sliding fit. The fixed core (4) is then tightly fitted with the fitting hole of the fixed crossbar (3) and the screw is inserted into the screw hole from the small tail end (2) on the reverse side to lock it. ⑥ The eccentric wheel trident tube (5) has screw holes on each fork. While aligning with the three screw countersunk holes of the lead screw connecting ring (9), the outer circle of the trident tube is kept in close fit with the countersunk hole of the lead screw connecting ring (9). Three screws are inserted to lock the three forks of the trident tube (5). The other end face of the lead screw connecting ring (9) is tightly fitted with the large countersunk hole of the lead screw nut (14) and six screws are locked. ⑦ The motor fixing connecting plate (10) is fitted from the end of the lead screw shaft connector (16) and tightly fitted with the large countersunk hole of the middle fixing plate (8). Four screws are inserted from the reverse side of the fixing plate to lock the motor fixing connecting plate. The servo motor (17) central shaft is inserted into the other end of the lead screw shaft connector (16), and the motor fits tightly with the large countersunk hole of the intermediate fixing plate (8). Four screws are inserted from the motor end to lock the two together. The two ends of the lead screw shaft connector (16) are fitted with the two shafts respectively and then the screws on them are tightened. ⑧ The entire set of equipment is fixed to the hydraulic tail jack fixed shaft end through the hydraulic tail jack fixed assembly plate (19) (the hydraulic tail jack does not need to have a rotary bearing and sleeve part here). The structural design and assembly of the entire equipment must meet the following requirements: the small tail jack and the machine tool spindle are on the same center, and the hydraulic tail jack is also usually on the same center. The outer wheel (7) of the eccentric wheel is in close contact with the inner wall of the pre-folded straight cylinder. The eccentric wheel trident tube (5) can slide freely on the fixed mandrel (4) and meet the parallelism requirements with the small tail jack (2) and the spindle center, usually within 5 to 10 microns. Finally, after everything is properly adjusted, the three places where the individual screws are tightened are appropriately welded to enhance the strength. Note that the solder joints should not affect the overall performance of the equipment.

[0008] Two-method implementation ① Place the pre-folded straight cylinder into the folding die (20). The entire set of liftable eccentric tail jacks, under the force of the hydraulic tail jack (18), pushes forward to press the straight cylinder firmly into the die cavity. ② The machine tool spindle rotates, and at the same time, the servo motor (17) drives the eccentric wheel to rise until it reaches the desired starting folding position. The folding wheel runs to the initial feed point under the XZ axis drive of the machine tool. ③ Through the precise programmable linkage between the eccentric wheel and the folding wheel, the straight cylinder edge is precisely folded from the outside to the inside, from top to bottom. ④ After the inner folding is completed, the machine tool spindle stops rotating, the hydraulic tail jack retracts and takes the folded finished product out of the concave mold cavity, and the finished product is taken out. The whole inner folding process is completed. (Note: When designing, the total maximum outer diameter of the small tail jack (2) and the outer sleeve wheel (7) of the eccentric wheel must be smaller than the diameter after the inner folding, otherwise the finished product cannot be taken out.) Three. Explanation of the linkage between equipment and method In this process embodiment, the inner folding is successfully implemented in one step by lifting the eccentric wheel and programmably linking it with the folding wheel. It is highly dependent on the specific structure of the equipment: ① The small tail jack (2) is connected to the fixed crossbar (3) and the fixed core rod (4) to form a "Z" structure, and a larger space is reserved for the placement of the lifting eccentric wheel (6+7). This "Z" shaped device is then fixedly connected to the hydraulic tail jack through the hydraulic tail jack connecting sleeve (19). ② Liftable structure: One end of the eccentric wheel trident tube (5) is tightly fitted with a pair of tapered bearings in the eccentric wheel (6+7) and tightened by a locking nut, thereby ensuring that the eccentric wheel (6+7) can rotate around the center of the trident tube. The eccentric wheel trident tube (5) is also slidably fitted to the fixed mandrel (4) (this structure makes full use of the space created by the above "Z" shaped structure). The trident part of the eccentric wheel trident tube (5) can also be inserted and slidably fitted to the central fixed plate (8), and finally connected to the lead screw (15) through the lead screw connecting ring (9). ③ Servo structure: The lead screw (15) shaft connector (16) is highly connected to the servo motor (17). The servo motor (17) is then connected and fixed to the middle fixed plate (8) through the motor fixed connecting plate (10). ④ At this point, the intermediate fixing plate (8) becomes an important base plate connecting the upper hydraulic tail top (18) and the lower "Z"-shaped combination structure, as well as the entire liftable structure and servo drive structure. The intermediate fixing plate (8) and the tail top connecting sleeve plate (19) are fixedly connected to the hydraulic tail top (18). Thus, the entire equipment is driven by the hydraulic tail top, with the lifting eccentric wheel (6+7) acting as one axis under the drive of the servo motor, and simultaneously precisely programmably linked with the two axes (X, Z) of the folding wheel, thereby realizing the most core and creative folding forming action in the process method of this invention.

Claims

1. A three-axis linkage system consisting of a servo-driven, independently extendable eccentric wheel and tail-end assembly, and a folding wheel on two axes (X and Z axes). This system enables precise one-time folding. The feature of the claim is that it includes the following steps: Step S1: Loading the cylindrical part. Place the cylindrical part to be folded (21) into the folding cylindrical die (20) and start the pre-programmed program of the CNC spinning machine. The entire set of liftable eccentric wheels and tail-end equipment (26) will be pushed forward into the cylindrical die (20) under the force of the hydraulic tail-end (18), firmly pressing the cylindrical part into the die cavity. The hydraulic tail-end pressure is generally adjusted to between 1.5Mpa and 5Mpa, depending on the size, material characteristics and thickness of the cylindrical part.

2. Step S2: The spindle (22) of the CNC spinning machine rotates, and the adjustable eccentric wheel is positioned. The spindle (22) drives the connecting folding straight cylinder die (20) to rotate at a constant speed. The adjustable eccentric wheel (6+7) rises under the drive of the servo motor (17) until the required pre-folding starting position is reached. At the same time, the folding wheel (23) reaches the initial folding position under the combined drive of the X-axis (24) and Z-axis (27) of the spinning machine. The spindle speed is usually 60-350 rpm, and the larger the straight cylinder, the lower the speed.

3. Step S3: Three-axis linkage folding. Through the uniform downward movement of the eccentric wheels (6+7) and the three-axis linkage clamping of the folding wheel (23), a precisely sized and perfectly shaped inner-folded finished product is obtained. The linkage consists of the X-axis (24), Z-axis (27) of the spinning machine, and the eccentric wheel axis (15). The fitting path of the folding wheel is a straight line diagonally downwards. The entire folding process is controlled by a pre-edited CNC program.

4. Step S4: Folding complete, remove the product. The spindle (22) of the CNC spinning machine stops rotating, and the entire set of lifting eccentric wheel and tail top equipment (26) is steadily retracted under the drive of the hydraulic tail top (at which time the program ends) and the folded finished product is taken out together.

5. The three-axis linkage folding process method of eccentric wheel and folding wheel according to claim 1, characterized in that... The program in step S3 presets a three-axis feed F value, typically 80-200 meters per minute, which is usually positively correlated with the spindle speed; the higher the speed, the larger the feed F value. The value should be set according to the actual situation.

6. The method for folding edges based on a liftable eccentric wheel and a tail-top assembly according to claim 1, characterized in that... The example of the lifting eccentric wheel and tail top complete equipment (26) in steps S1 to S4 includes: ① Small tail top and fixed "Z" shaped structure (see Figure 6), which includes small tail top (2), tail top spindle (1), bearing (11), fixed crossbar (3), fixed core rod (4), and intermediate fixed plate (8). ② Liftable structure and servo part structure (see Figure 5). It includes inner eccentric wheel (6), outer eccentric wheel (7), tapered bearing (13), locking nut (12), eccentric wheel three-way tube (5), intermediate fixed plate (8), lead screw connecting ring (9), lead screw nut (14), lead screw (15), shaft connector (16), servo motor (17), and motor fixing plate (10).

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