A slotted bush forming machine and forming process

Abstract

The present application relates to the technical field of slotted bush forming, in particular to a slotted bush forming machine and a forming process. The forming machine comprises a gradual extrusion forming machine and a conical forming machine. The gradual extrusion forming machine comprises a slotted bush forming die and a conveying roller group and a traction machine arranged on both sides of the slotted bush forming die respectively. The slotted bush forming die is used to complete the gradual extrusion forming of the thin-walled hard material plane strip. The traction machine is used to pull the slotted cylinder semi-finished product out of the slotted bush forming die. The conical forming machine comprises a female die, a male die and a ejector rod. The ejector rod is in sliding fit with the female die at the bottom of the female die. The slotted bush sleeve is sleeved on the male die. The male die is above the female die and realizes die closing with the female die. The slotted bush sleeve is extruded into a slotted bush with a tapered portion and a flange portion. The ejector rod ejects the slotted bush. The present application makes the forming size of the thin-walled hard material stable, realizes stable production, and improves the production and research and development efficiency.

Description

Technical Field

[0001] This invention relates to the field of slotted bushing forming technology, specifically to a slotted bushing forming machine tool and forming process. Background Technology

[0002] Slotted bushings are core components of aircraft fastener connections, and their cold extrusion hole strengthening technology is a key process for improving the structural strength and service life of aircraft. Currently, the forming processes for slotted bushings both domestically and internationally mainly employ rolling methods or one-time stamping forming technology, but these methods suffer from the following fatal flaws:

[0003] Thin-walled hard materials are difficult to form: Existing processes for hard metal materials cannot achieve uniform deformation, which easily leads to cracking, wrinkling, and low forming qualification rate.

[0004] Poor dimensional stability: The rounding method relies on the line contact drive of multiple sets of rollers, which is prone to large deviations in bushing roundness due to uneven contact stress, and cannot meet the high-precision assembly requirements of aircraft.

[0005] One-time stamping requires customized molds for bushings of different specifications, resulting in long changeover cycles, high equipment costs, and complex maintenance.

[0006] Therefore, there is an urgent need for a slotted bushing forming machine tool and forming process that can adapt to thin-walled hard materials, ensure dimensional accuracy, and integrate intelligent control, in order to break through the technical bottleneck. Summary of the Invention

[0007] To address the aforementioned problems, the present invention aims to provide a slotted bushing forming machine tool and forming process to solve the forming difficulties of slotted bushings made of thin-walled hard materials, while realizing intelligent control of product quality and serialized production.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] The present invention provides a slotted bushing forming machine tool, including a gradient extrusion forming machine tool and a conical forming machine tool. The gradient extrusion forming machine tool is used for one-time forming of slotted bushings, and the conical forming machine tool is used for two-time forming of slotted bushings.

[0010] The gradient extrusion molding machine includes a slit bushing forming die and conveying roller sets and a traction machine respectively set on both sides of the slit bushing forming die. The conveying roller sets are used to convey the thin-walled hard material flat strip into the slit bushing forming die. The slit bushing forming die is used to complete the gradient extrusion molding of the thin-walled hard material flat strip to obtain a slit cylindrical semi-finished product. The traction machine is used to pull the slit cylindrical semi-finished product out of the slit bushing forming die and cut it to obtain a slit sleeve.

[0011] The cone forming machine tool includes a die, a punch, and an ejector pin. The die has a conical groove and a flanged forming arc at the top of the conical groove. The outer surface taper of the punch is adapted to the die. The ejector pin slides with the bottom of the die. A slit sleeve is fitted on the punch. The punch is above the die and closes with it. The slit sleeve is compressed into a slit bushing with a conical part and a flanged part. The ejector pin is used to eject the slit bushing.

[0012] The slotted bushing forming mold includes an upper mold, a lower mold, and a core mold. The upper mold and the lower mold are closed to form a forming cavity, which includes an extrusion cavity with a gradually changing inner diameter and a cylindrical extrusion cavity.

[0013] The core mold includes a support part and a mandrel disposed at the bottom of the support part. The mandrel is disposed in the forming cavity. The upper mold and the lower mold cooperate to gradually shape the outer side of the thin-walled rigid material planar strip, and the mandrel gradually shapes the inner side of the thin-walled rigid material planar strip.

[0014] The top of the lower mold is the lower mold box-closing surface and the lower forming groove provided on the lower mold box-closing surface. The lower forming groove includes the lower mold gradient curved surface and the lower mold semi-cylindrical curved surface.

[0015] The upper mold includes a symmetrically arranged upper left mold and an upper right mold; the upper left mold and the upper right mold have the same structure, both including an upper mold box-closing surface and an upper forming groove provided on the upper mold box-closing surface, the upper forming groove including an upper mold gradient curved surface and an upper mold semi-cylindrical curved surface; the two symmetrically arranged upper mold gradient curved surfaces and the lower mold gradient curved surface of the lower mold surround to form the inner diameter gradient extrusion cavity; the two symmetrically arranged upper mold semi-cylindrical curved surfaces and the lower mold semi-cylindrical curved surface of the lower mold surround to form the cylindrical extrusion cavity.

[0016] The mandrel includes a shaped cylindrical curved section, a mandrel gradually changing guide curved section, and a supporting cylindrical section arranged along the axial direction. The shaped cylindrical curved section is housed in the cylindrical extrusion cavity and forms a cylindrical annular gap with the inner wall of the cylindrical extrusion cavity. The mandrel gradually changing guide curved section is housed in the inner diameter gradually changing extrusion cavity and forms an inner diameter gradually changing annular gap with the inner wall of the inner diameter gradually changing extrusion cavity.

[0017] The traction machine includes a base, a traction core column, a gripper, a conforming table, and a linear drive module. The linear drive module is mounted on the base and its output end is connected to the traction core column. The traction core column is collinear with the axis of the spindle and is used to support the slit sleeve formed by the slit bushing forming mold from the inside.

[0018] The conforming platform is slidably connected to the base along a direction parallel to the linear drive module. The gripper is set on the conforming platform and clamps the slit sleeve supported by the traction core column on the outside. The linear drive module drives the traction core column to move away from the core shaft and pulls the slit sleeve to the outside of the slit bushing forming mold.

[0019] The lower end of the punch has a tapered forming part and an arc-shaped flange groove located at the top of the tapered forming part; the slit sleeve is fitted onto the outside of the tapered forming part of the punch.

[0020] Another aspect of the present invention provides a slit bushing forming process using the forming machine tool described above, comprising the following steps:

[0021] Step S1: Raw material preparation, selecting thin-walled rigid material flat strip;

[0022] Step S2: Servo feeding and shaping;

[0023] Step S3: Gradient extrusion molding, using a gradient extrusion molding machine to gradually extrude and deform a thin-walled rigid material strip into a slotted cylindrical semi-finished product;

[0024] Step S4: Laser cutting to obtain a slotted sleeve;

[0025] Step S5: Conical forming, the slit sleeve is pressed into a finished slit bushing with a conical part and a flanged part by a conical forming machine.

[0026] The gradient extrusion molding process includes the following steps:

[0027] Step S31: The upper and lower dies close and apply pressure. The upper and lower dies guide the thin-walled rigid material strip to gradually deform on the outside, while the mandrel supports it from the inside.

[0028] Step S32: The traction core of the traction machine is inserted into the end of the slit cylindrical semi-finished product, the gripper extends and retracts radially to apply clamping force, and the linear drive module drives the conforming table to move axially, sending the slit cylindrical semi-finished product to the laser cutting station.

[0029] The cone-shaped forming process includes the following steps:

[0030] Step S51: Place the slit sleeve into the self-locking position of the punch;

[0031] Step S52: The punch moves downward and presses the slit sleeve into the die. At this time, there is a micro gap of 0.01-0.02mm between the punch and die and the slit sleeve.

[0032] Step S53: The push rod moves upward to push the lower part of the slotted sleeve, and works with the die to form the cone and the flange, thus obtaining the slotted bushing;

[0033] Step S54: The punch moves upward to demold;

[0034] Step S55: The push rod moves upward to push out the slotted bushing.

[0035] The advantages and positive effects of this invention are as follows: The slotted bushing forming machine tool provided by this invention solves the forming problem of slotted bushings of thin-walled hard materials by the synergy of secondary forming equipment of gradual extrusion forming and conical forming and artificial intelligence optimization module, and realizes intelligent control of product quality and serialized production.

[0036] This invention employs a two-stage forming process: breaking down traditional one-time stamping into "gradual extrusion forming (cylindrical semi-finished product) + conical forming (finished product)," achieving uniform deformation of thin-walled hard materials through surface contact gradual shaping; the gradual extrusion machine tool structure features symmetrical upper and lower die curved surface fit, a gradual guiding structure for the core die, and surface contact servo clamping of the traction machine, solving the problems of uneven line contact stress and slippage; the conical forming micro-gap control uses a 0.01-0.02mm micro-gap design between the punch, die, and sleeve to ensure the dimensional accuracy of the conical part (2° taper) and the flanged part. Attached Figure Description

[0037] Figure 1 This is an isometric view of the gradient extrusion molding machine tool in this invention;

[0038] Figure 2 This is a partial cross-sectional view of the gradient extrusion molding machine tool in this invention;

[0039] Figure 3 This is a schematic diagram of the forming process of the thin-walled rigid material in this invention;

[0040] Figure 4 This is a schematic diagram of the lower mold structure in this invention;

[0041] Figure 5 This is a schematic diagram of the upper mold in this invention;

[0042] Figure 6 This is a schematic diagram of the core mold in this invention;

[0043] Figure 7 This is a schematic diagram of the traction machine in this invention;

[0044] Figure 8 This is a schematic diagram of the slit sleeve in the present invention;

[0045] Figure 9 This is a planar unfolded schematic diagram of the slotted sleeve in this invention;

[0046] Figure 10 This is a schematic diagram of the structure of the slotted bushing in this invention;

[0047] Figure 11 This is a schematic diagram of the initial state of the cone forming machine tool in this invention;

[0048] Figure 12This is a schematic diagram of the working state of the cone forming machine tool in this invention;

[0049] Figure 13 for Figure 12 A magnified view of a portion of point A in the middle.

[0050] In the diagram: 1. Thin-walled rigid material flat strip; 101. Coil section; 102. Flat section; 103. Gradiently deformed section; 104. Slit cylindrical section; 2. Roller; 3. Lower die; 301. Gradiently curved section of the lower die; 302. Semi-cylindrical curved section of the lower die; 303. Closing section of the lower die; 4. Upper left die; 401. Gradiently curved section of the upper die; 402. Semi-cylindrical curved section of the upper die; 403. Closing section of the upper die; 5. Upper right die; 6. Core die; 601. Shaping cylindrical curved section; 602. Core die 603. Gradient guide curved surface; 604. Supporting cylindrical part; 605. Supporting vertical plate part; 606. Supporting block part; 7. Traction machine; 701. Base; 702. Traction core column; 703. Gripper; 704. Conforming stage; 705. Linear drive module; 8. Slit sleeve; 801. Lower side; 802. Upper side; 803. Left side; 804. Right side; 9. Slit bushing; 901. Slit part; 902. Conical part; 903. Flanged part; 10. Die; 11. Punch; 12. Ejector rod. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0052] See Figures 1 to 13 As shown, one embodiment of the present invention provides a slotted bushing forming machine tool, including a gradient extrusion forming machine tool and a conical forming machine tool. The gradient extrusion forming machine tool is used for one-time forming of slotted bushings, and the conical forming machine tool is used for two-time forming of slotted bushings. Through the collaboration of the two forming equipment of gradient extrusion forming and conical forming and the artificial intelligence optimization module, the forming problem of slotted bushings of thin-walled hard materials is solved, and intelligent control of product quality and serialized production are realized at the same time.

[0053] See Figure 1 and Figure 2 As shown in the embodiment of the present invention, the gradient extrusion molding machine includes a slit bushing forming mold and conveying roller groups and a traction machine 7 respectively arranged on both sides of the slit bushing forming mold. The thin-walled hard material flat strip 1 is conveyed to the slit bushing forming mold through the conveying roller group, and the gradient extrusion is completed in the slit bushing forming mold to obtain a slit cylindrical semi-finished product. The traction machine 7 is used to pull the slit cylindrical semi-finished product out of the slit bushing forming mold, and after cutting, a slit sleeve 8 is obtained.

[0054] In embodiments of the present invention, the slit bushing forming mold includes an upper mold, a lower mold 3, and a core mold 6. After the upper mold and the lower mold 3 are closed, a forming cavity is formed. The forming cavity includes an inner diameter gradient extrusion cavity and a cylindrical extrusion cavity. The core mold 6 includes a support portion and a mandrel disposed at the bottom of the support portion. The mandrel is disposed in the forming cavity. The upper mold and the lower mold 3 cooperate to gradually shape the outer side of the thin-walled rigid material planar strip 1, and the mandrel gradually shapes the inner side of the thin-walled rigid material planar strip 1.

[0055] See Figure 4 As shown, in an embodiment of the present invention, the top of the lower mold 3 is a lower mold box-closing surface 303 and a lower forming groove disposed on the lower mold box-closing surface 303. The lower forming groove includes a lower mold gradient curved surface 301 and a lower mold semi-cylindrical curved surface 302.

[0056] See Figure 1 and Figure 5 As shown, in an embodiment of the present invention, the upper mold includes a left upper mold 4 and a right upper mold 5 symmetrically arranged; the left upper mold 4 and the right upper mold 5 have the same structure, both including an upper mold box-closing surface 403 and an upper forming groove disposed on the upper mold box-closing surface 403, the upper forming groove including an upper mold gradient curved surface 401 and an upper mold semi-cylindrical curved surface 402; the two symmetrically arranged upper mold gradient curved surfaces 401 and the lower mold gradient curved surface 301 of the lower mold 3 enclose each other to form an inner diameter gradient extrusion cavity; the two symmetrically arranged upper mold semi-cylindrical curved surfaces 402 and the lower mold semi-cylindrical curved surface 302 of the lower mold 3 enclose each other to form a cylindrical extrusion cavity.

[0057] Specifically, the shape and size of the forming cavity of the slotted bushing forming die are precisely machined according to the gradient requirements of the slotted bushing 8. For example, for slotted bushings with a gradient trend in inner or outer diameter, the forming cavity of the die can be precisely adapted to it, so that the material is uniformly deformed during the extrusion process to achieve the required gradient shape.

[0058] See Figure 6 As shown, in an embodiment of the present invention, the support portion includes a support plate portion 604 and a support block portion 605, with the support plate portion 604 connected to the support cylindrical portion 603. The mandrel includes a shaped cylindrical curved portion 601, a mandrel-shaped guide curved portion 602, and the support cylindrical portion 603 arranged sequentially along the axial direction. The shaped cylindrical curved portion 601 and the mandrel-shaped guide curved portion 602 are fixed to the bottom of the support block portion 605, and the shaped cylindrical curved portion 601 is housed within a cylindrical extrusion cavity, forming a cylindrical forming annular gap between the shaped cylindrical curved portion 601 and the inner wall of the cylindrical extrusion cavity. The mandrel-shaped guide curved portion 602 is housed within an inner diameter-gradient extrusion cavity, forming an annular extrusion cavity with a gradually changing inner diameter between it and the inner diameter-gradient extrusion cavity. The support cylindrical portion 603 is fixed to the bottom of the support plate portion 604.

[0059] See Figure 1 and Figure 2As shown, in an embodiment of the present invention, the conveying roller group includes two rollers 2 arranged vertically, and a thin-walled rigid material flat strip 1 passes between the two rollers 2 for shaping and conveying.

[0060] Referring to Figure 3, the thin-walled rigid material flat strip 1 is divided into a coil section 101, a flat section 102, a gradually deforming section 103, and a slotted cylindrical section 104 along the forward conveying direction. The coil section 101 is fed by a servo drive. The end of the flat section 102 is shaped by two rollers 2. The lower die 3, upper left die 4, and upper right die 5 of the gradually extruding slotted bushing forming machine gradually shape the outer side of the gradually deforming section 103. That is, the upper die gradually curved surface 401 and the upper die semi-cylindrical curved surface 402 cooperate with the lower die gradually curved surface 301 and the lower die semi-cylindrical curved surface 302 to gradually shape the outer side of the gradually deforming section 103 of the thin-walled rigid material flat strip 1. The contact method is surface contact to avoid stress concentration from line contact. The core die 6 gradually shapes the inner side of the gradually deforming section 103, guiding the material to gradually transition from a flat surface to a cylindrical shape. The deformation rate can be adjusted by a servo motor. The end of the slotted cylindrical section 104 can be pulled by the traction machine 7 to achieve surface contact traction and ensure the synchronization of stepping production.

[0061] See Figure 7 As shown, in an embodiment of the present invention, the traction machine 7 includes a base 701, a traction core column 702, a gripper 703, a conforming platform 704, and a linear drive module 705. The linear drive module 705 is disposed on the base 701, and its output end is connected to the traction core column 702. The traction core column 702 is collinear with the axis of the mandrel, and the end of the traction core column 702 extends into the interior of the slotted sleeve 8. The traction core column 702 is used to support the slotted sleeve 8 formed by the slotted bushing forming mold from the inside. The conforming platform 704 is slidably connected to the base 701 in a direction parallel to the linear drive module 705. The gripper 703 is disposed on the conforming platform 704 and grips the slotted sleeve 8 supported by the traction core column 702 from the outside. The linear drive module 705 drives the traction core column 702 to move away from the mandrel, thereby pulling the slotted sleeve 8 to the outside of the slotted bushing forming mold. At the same time, the gripper 703 and the conforming stage 704 move synchronously with the traction core 702.

[0062] Specifically, the gripper 703 has a symmetrical structure and is hydraulically driven to clamp or release. The traction core 702 extends into the inner side of the slotted cylindrical part 104 to ensure coaxiality. The gripper 703 achieves surface contact traction through radial servo extension and axial servo movement of the conforming table 704, which increases friction and eliminates the need for multiple sets of roller compensation. This reduces the number of drive components in the equipment and lowers maintenance costs.

[0063] See Figure 8 and Figure 9As shown in the embodiment of the present invention, the lower edge 801 and the upper edge 802 of the slit sleeve 8 are both spatial curves; the side wall of the slit sleeve 8 is provided with a slit, and the left side 803 and the right side 804 of the slit are both spatial curves.

[0064] In the embodiments of the present invention, a gradient extrusion forming design is adopted to overcome the limitations of traditional line contact drive. The gradient extrusion forming machine tool forms an "internal and external synergistic surface contact gradient forming" by using the lower die gradient curved surface 301, the upper die gradient curved surface 401 and the core die gradient guide curved surface 602. This ensures that the contact stress is evenly distributed during the deformation process of the thin-walled rigid material strip 1 from the flat part 102 to the gradient deformation part 103 and then to the slotted cylindrical part 104. This avoids cracking and wrinkling of the thin-walled material due to local stress concentration, and greatly improves the forming qualification rate.

[0065] See Figures 11 to 13 As shown, in an embodiment of the present invention, the conical forming machine tool includes a die 10, a punch 11, and an ejector pin 12. The die 10 has a conical groove and a flanged forming arc at the top of the conical groove. The outer surface taper of the punch 11 is adapted to the die 10, and it has a conical forming portion and an arc-shaped flanged groove at the top of the conical forming portion. The ejector pin 12 slides with the bottom of the die 10, and a slit sleeve 8 is fitted onto the outside of the conical forming portion of the punch 11. The punch 11 closes with the die 10 above it, and the slit sleeve 8 is compressed into a slit bushing 9 with a conical portion and a flanged portion. The ejector pin 12 is used to eject the slit bushing 9. Specifically, the conical forming portion of the punch 11 is a 2° conical surface.

[0066] Specifically, the slit sleeve 8 is self-locking with elasticity and friction at a certain height position on the ejector pin 12, and the punch 11 and the ejector pin 12 can move up and down servo-driven. The punch 11 with the slit sleeve 8 is fitted with the die 10 to a certain position, and a certain micro gap is formed between the slit sleeve 8, the punch 11, and the die 10. The ejector pin 12 pushes the lower part of the slit sleeve 8 to rise into place.

[0067] See Figure 10 As shown, in an embodiment of the present invention, the slotted bushing 9 includes a tapered portion 902, a slotted portion 901 disposed on the side wall of the tapered portion 902, and a flanged portion 903 disposed at the upper end of the tapered portion 902. In this embodiment, the slotted bushing 9 is made of titanium or 1Cr17Ni7 hard stainless steel, with a wall thickness of 0.2 mm. The taper of the tapered portion 902 is 2°, and the flanged portion 903 is required for disassembly during application.

[0068] In the embodiments of the present invention, "cylindrical forming" and "conical / flanging forming" are separated. The first step is to achieve precise shaping of the "cylindrical semi-finished product" through gradual extrusion. The second step is to complete the forming of the conical part 902 and the flanging part 903 by using the 2° conical surface of the conical forming machine tool's die 10 to adapt to the punch 11 and the elastic self-locking position of the ejector pin 12. During the forming process, the punch, die and the slit sleeve 8 form a micro gap of 0.01-0.02mm to ensure the stability of the taper accuracy and the flanging height, thus solving the problem of "insufficient accuracy of simultaneous processing of multiple features" in one-time forming.

[0069] In the embodiments of the present invention, the thin-walled rigid material planar strip 1 is made of titanium or 1Cr17Ni7 with a wall thickness of 0.2mm. It utilizes the gradual forming process of a gradual extrusion forming machine and then a conical forming machine to transform the one-time stamping forming into a two-time forming process. This process solves the problem of the difficulty in forming thin-walled rigid materials. Through the artificial intelligence-optimized "two-time forming + surface contact process", the forming dimensions of the thin-walled rigid material are stabilized, achieving stable production; improving production and R&D efficiency: when changing specifications, artificial intelligence reduces the number of process iterations and shortens the R&D cycle; by collecting multimodal data through artificial intelligence modules, training with digital twins, and then performing virtual-real interaction optimization, intelligent quality control is achieved, reducing the cost of physical trial and error.

[0070] See Figures 1 to 13 As shown, another embodiment of the present invention provides a slotted bushing forming process, which is implemented using the slotted bushing forming machine tool in the above embodiment; the forming process includes the following steps:

[0071] Step S1: Raw material preparation, select thin-walled rigid material flat strip 1;

[0072] Step S2: Servo feeding and shaping;

[0073] Step S3: Gradient extrusion molding, the thin-walled rigid material flat strip 1 is gradually extruded and deformed into a slotted cylindrical semi-finished product by a gradient extrusion molding machine.

[0074] Step S4: Laser cutting, using a six-degree-of-freedom laser cutting robot to cut the slit cylindrical semi-finished product to obtain the slit sleeve 8;

[0075] Step S5: Conical forming, the slit bushing 8 is pressed into a finished slit bushing 9 with a conical part and a flanged part by a slit bushing conical forming machine.

[0076] In embodiments of the present invention, the gradient extrusion molding process of the thin-walled rigid material planar strip 1 includes the following steps:

[0077] Step S31: The upper and lower dies 3 of the gradient extrusion molding machine are closed to apply pressure. The thin-walled hard material strip 1 is gradually deformed on the outside by the upper and lower dies 3, while the mandrel supports it from the inside.

[0078] Step S32: The traction core column 702 of the traction machine 7 enters the end of the slit cylindrical semi-finished product, the gripper 703 extends and retracts radially to apply clamping force, and the linear drive module 705 drives the conforming table 704 to move axially, sending the slit cylindrical semi-finished product to the laser cutting station.

[0079] In embodiments of the present invention, the tapered forming process of the slotted sleeve 8 includes the following steps:

[0080] Step S51: Place the slit sleeve 8 into the self-locking position of the punch 11;

[0081] Step S52: The punch 11 moves downward and presses the slit sleeve 8 into the die 10. At this time, there is a micro gap of 0.01-0.02mm between the punch 11, the die 10 and the slit sleeve 8.

[0082] Step S53: The push rod 12 moves upward to push the lower part of the slotted sleeve 8, and cooperates with the die 10 to complete the forming of the cone 902 and the flange 903, thus obtaining the slotted bushing 9;

[0083] Step S54: Punch 11 moves upward to demold;

[0084] Step S55: The push rod 12 moves upward to push out the slotted bushing 9, thus obtaining the slotted bushing 9.

[0085] This invention employs a two-stage forming process: breaking down traditional one-time stamping into "gradual extrusion forming (cylindrical semi-finished product) + conical forming (finished product)," achieving uniform deformation of thin-walled hard materials through surface contact gradual shaping; the gradual extrusion machine tool structure: symmetrical upper and lower die curved surface fit, gradual guide structure of the core die, and surface contact servo clamping of the traction machine solve the problems of uneven line contact stress and slippage; conical forming micro-gap control: 0.01-0.02mm micro-gap design of the punch, die, and sleeve ensures the dimensional accuracy of the conical part (2° taper) and the flanged part.

[0086] The above description is merely an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, extensions, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A slotted bushing forming machine tool, characterized in that, It includes a gradient extrusion molding machine and a cone forming machine. The gradient extrusion molding machine is used for one-time forming of slotted bushings, and the cone forming machine is used for two-time forming of slotted bushings. The gradient extrusion molding machine includes a slit bushing forming die and a conveying roller group and a traction machine (7) respectively set on both sides of the slit bushing forming die. The conveying roller group is used to convey the thin-walled hard material flat strip (1) into the slit bushing forming die. The slit bushing forming die is used to complete the gradient extrusion molding of the thin-walled hard material flat strip (1) to obtain a slit cylindrical semi-finished product. The traction machine (7) is used to pull the slit cylindrical semi-finished product out of the slit bushing forming die and cut it to obtain a slit sleeve (8). The cone forming machine tool includes a die (10), a punch (11), and an ejector pin (12). The die (10) has a conical groove and a flange forming arc at the top of the conical groove. The outer surface taper of the punch (11) is adapted to the die (10). The ejector pin (12) slides with the bottom of the die (10). The slit sleeve (8) is fitted on the punch (11). The punch (11) is above the die (10) and closes with the die (10). The slit sleeve (8) is squeezed into a slit bushing (9) with a conical part and a flange part. The ejector pin (12) is used to eject the slit bushing (9). The slotted bushing forming mold includes an upper mold, a lower mold (3) and a core mold (6), wherein the upper mold and the lower mold (3) are closed to form a forming cavity, and the forming cavity includes an inner diameter gradually changing extrusion cavity and a cylindrical extrusion cavity; The core mold (6) includes a support part and a core shaft disposed at the bottom of the support part. The core shaft is disposed in the molding cavity. The upper mold and the lower mold (3) cooperate to gradually shape the outer side of the thin-walled hard material planar strip (1), and the core shaft gradually shapes the inner side of the thin-walled hard material planar strip (1). The top of the lower mold (3) is the lower mold box-joining surface (303) and the lower forming groove provided on the lower mold box-joining surface (303). The lower forming groove includes the lower mold gradient curved surface (301) and the lower mold semi-cylindrical curved surface (302). The upper mold includes a left upper mold (4) and a right upper mold (5) arranged symmetrically. The left upper mold (4) and the right upper mold (5) have the same structure, both including an upper mold box-closing surface (403) and an upper forming groove provided on the upper mold box-closing surface (403). The upper forming groove includes an upper mold gradient curved surface (401) and an upper mold semi-cylindrical curved surface (402). The two symmetrically arranged upper mold gradient curved surfaces (401) and the lower mold gradient curved surface (301) of the lower mold (3) enclose to form the inner diameter gradient extrusion cavity. The two symmetrically arranged upper mold semi-cylindrical curved surfaces (402) and the lower mold semi-cylindrical curved surface (302) of the lower mold (3) enclose to form the cylindrical extrusion cavity. The mandrel includes a shaped cylindrical curved part (601), a mandrel gradually changing guide curved part (602), and a supporting cylindrical part (603) arranged along the axial direction. The shaped cylindrical curved part (601) is housed in the cylindrical extrusion cavity and forms a cylindrical annular gap with the inner wall of the cylindrical extrusion cavity. The mandrel gradually changing guide curved part (602) is housed in the inner diameter gradually changing extrusion cavity and forms an inner diameter gradually changing annular gap with the inner wall of the inner diameter gradually changing extrusion cavity.

2. The slotted bushing forming machine tool according to claim 1, characterized in that, The traction machine (7) includes a base (701), a traction core column (702), a gripper (703), a conformal stage (704), and a linear drive module (705). The linear drive module (705) is mounted on the base (701) and its output end is connected to the traction core column (702). The traction core column (702) is collinear with the axis of the spindle. The traction core column (702) is used to support the slotted sleeve (8) formed by the slotted bushing forming mold from the inside. The conforming stage (704) is slidably connected to the base (701) in a direction parallel to the linear drive module (705). The gripper (703) is set on the conforming stage (704). The gripper (703) clamps the slit sleeve (8) supported by the traction core column (702) on the outside. The linear drive module (705) drives the traction core column (702) to move away from the core shaft, pulling the slit sleeve (8) to the outside of the slit bushing forming mold.

3. The slotted bushing forming machine tool according to claim 1, characterized in that, The lower end of the punch (11) has a conical forming part and an arc-shaped flange groove located at the top of the conical forming part; the slit sleeve (8) is fitted onto the outside of the conical forming part of the punch (11).

4. A slit bushing forming process using the forming machine tool as described in claim 2, characterized in that, Includes the following steps: Step S1: Raw material preparation, select thin-walled rigid material flat strip (1); Step S2: Servo feeding and shaping; Step S3: Gradient extrusion molding, the thin-walled hard material flat strip (1) is gradually extruded and deformed into a slotted cylindrical semi-finished product by a gradient extrusion molding machine. Step S4: Laser cutting to obtain the slotted sleeve (8); Step S5: Conical forming, the slit sleeve (8) is pressed into a finished slit bushing (9) with a conical part and a flanged part by a conical forming machine.

5. The slotted bushing forming process according to claim 4, characterized in that, The gradient extrusion molding process includes the following steps: Step S31: The upper mold and the lower mold (3) close the mold and apply pressure. The thin-walled hard material flat strip (1) is gradually deformed on the outside by the upper mold and the lower mold (3), while the mandrel supports it from the inside. Step S32: The traction core column (702) of the traction machine (7) is inserted into the end of the slit cylindrical semi-finished product, the gripper (703) extends and retracts radially to apply clamping force, and the linear drive module (705) drives the conforming table (704) to move axially, sending the slit cylindrical semi-finished product to the laser cutting station.

6. The slotted bushing forming process according to claim 4, characterized in that, The cone-shaped forming process includes the following steps: Step S51: Place the slit sleeve (8) onto the self-locking position of the punch (11); Step S52: The punch (11) moves downward and presses the slit sleeve (8) into the die (10). At this time, there is a micro gap of 0.01-0.02mm between the punch (11), the die (10) and the slit sleeve (8). Step S53: The push rod (12) moves upward to push the lower part of the slotted sleeve (8), and cooperates with the die (10) to complete the forming of the cone (902) and the flange (903) to obtain the slotted bushing (9). Step S54: The punch (11) moves upward to demold; Step S55: The top rod (12) moves upward to push out the slit bushing (9).

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