Near-net-size high-load-bearing brake disc preform, sewing device and preparation method thereof

Abstract

The invention relates to a near-net-size high-bearing-capacity brake disc prefabricated body which comprises a surface friction layer, an in-plane bearing layer and a ventilation hole functional layer which are sewn and fixed through an N-shaped suture line, and the surface friction layer and the in-plane bearing layer are both in a circular ring shape; the fiber laying track of the surface friction layer is spiral, and the surface friction layer is divided into an upper surface friction layer and a lower surface friction layer; the in-plane bearing layer is composed of a 0-degree bearing layer and a 90-degree bearing layer; an upper in-plane bearing layer is arranged on the inner side of the upper surface friction layer, a lower in-plane bearing layer is arranged on the inner side of the lower surface friction layer, and a vent hole functional layer is arranged between the two in-plane bearing layers; the ventilation hole functional layer is composed of ventilation holes and supporting ribs which are alternately arranged along a circular ring, and the supporting ribs are composed of unit layers formed by alternately paving and sewing radial fan-shaped layers and annular fan-shaped layers. The invention further discloses a suturing device and a preparation method of the prefabricated body. The prefabricated body has the advantages of being resistant to abrasion, excellent in bearing performance and high in automation degree in the manufacturing process.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite material preforms, and is applied to braking fields such as airplanes, high-speed rails, and new energy vehicles. In particular, it relates to a near-net-size high-load brake disc preform, a stitching device, and a preparation method thereof. Background Art

[0002] Carbon / carbon composite brake discs exhibit significant advantages in the braking field due to their excellent high-temperature performance, low density, high strength, and outstanding wear resistance. Carbon / carbon composite brake discs include short fiber discs and long fiber discs. Among them, the short fiber molded disc (patent number CN202110471234.4) has discontinuous and randomly oriented short fiber products in the blank, lacking the high mechanical strength of continuous carbon fibers, resulting in poor structural mechanical properties, low strength, insufficient toughness, and prone to chipping and breakage. The long fiber disc uses the needling method to prepare the brake disc preform. Patent CN102152555A laminates a carbon fiber base cloth and a carbon fiber web tire at a specific angle and thickness, and uses a barbed needle for needling molding. However, the needling process inevitably damages the long fibers inside the base cloth, thereby reducing the mechanical properties of the brake disc. In addition, the Z-direction fibers introduced by needling are difficult to penetrate the entire thickness of the preform, and the interlayer bonding force in the thickness direction is also insufficient. At the same time, during the production of the needled brake disc preform, a large flat preform is cut into a ring-shaped preform, wasting a large amount of raw materials, which undoubtedly increases the production cost.

[0003] In order to effectively reduce raw material waste, patent US6319348B1 proposed a new solution, that is, using carbon fiber tows as raw materials, weaving them into two-dimensional fiber tapes, further preparing spiral fiber tapes by rolling and winding, and then laying and needling the spiral fiber tapes to form a ring-shaped brake disc preform. There is almost no raw material waste in the whole process. However, this method has a relatively complex process, bringing certain challenges to production efficiency and cost control. At the same time, the target yarn path is difficult to control, and it is difficult to control the properties of the preform and its composite materials.

[0004] To further simplify the production process, Patent US20060068150A1 introduces the Tailored Fiber Placement (TFP) technology and stitching technology to prepare the brake disc preform. The load-bearing layers with different fiber orientations are prepared by the TFP technology, including the radial distribution configuration of reinforcing fibers, circular distribution configuration, and involute distribution configuration. Further, the above load-bearing layers are connected and stitched by the stitching technology to form the semi-region part of the preform. Finally, also based on the stitching technology, the I-shaped bridge tabs, the upper half-region part, and the lower half-region part of the preform are stitched into an integral brake disc preform with ventilation holes. In addition, a short fiber layer is configured on the surface of the brake disc. This technology effectively realizes the near-net shaping preparation of the brake disc preform and reduces the loss of raw materials. However, the load-bearing layer is configured with fiber distribution layers in multiple directions, increasing the complexity of the process; the short fibers of the short fiber felt used in the surface friction layer limit the braking effect; the stitching operation space for the bridge tabs used to form the ventilation holes is limited, and the stitching process is difficult; in addition, the specific stitching technology adopted in this patent is not specifically given.

[0005] In summary, there are still many deficiencies in the prior art in the preparation of carbon / carbon composite brake disc preforms. Therefore, it is particularly necessary to explore a new type of near-net size and high-load brake disc preform and its preparation method, in order to break through the bottleneck of the existing technology, further improve the performance of the carbon / carbon composite brake disc, and meet the stringent requirements of the high-performance application field for brake discs. Summary of the Invention

[0006] The present invention provides a near-net size and high-load brake disc preform, a stitching device, and a preparation method thereof to solve the technical problems existing in the known technology, and has the characteristics of wear resistance, excellent load-bearing performance, and high degree of automation in the production process.

[0007] The present invention includes the following technical solutions:

[0008] A near-net size and high-load brake disc preform, comprising a surface friction layer, an in-plane load-bearing layer, and a ventilation hole functional layer stitched and fixed by N-shaped stitching threads. Both the surface friction layer and the in-plane load-bearing layer are circular rings; the fiber laying trajectory of the surface friction layer is spiral, and the surface friction layer is divided into an upper surface friction layer and a lower surface friction layer; the fiber laying trajectory of the in-plane load-bearing layer is linear and consists of a 0° load-bearing layer and a 90° load-bearing layer; an upper in-plane load-bearing layer is provided inside the upper surface friction layer, and a lower in-plane load-bearing layer is provided inside the lower surface friction layer. A ventilation hole functional layer is provided between the two in-plane load-bearing layers; the ventilation hole functional layer is composed of ventilation holes and support ribs alternately arranged along the circular ring. The support ribs are composed of unit layers alternately laid and stitched by radial fan-shaped layers and circumferential fan-shaped layers, and several of the unit layers are stacked from bottom to top to form the support ribs.

[0009] A stitching device for preparing the above-mentioned brake disc preform, comprising two six-axis stitching robotic arms equipped with stitching end effectors and a stitching workbench. The stitching workbench includes a stitching tooling and a T-slot platform, and the stitching tooling is installed on the top surface of the T-slot platform. The stitching tooling consists of five parts: a front cover plate, a rear cover plate, a ventilation hole positioning device, an inner frame, and an outer frame. The front cover plate and the rear cover plate are symmetrically distributed and installed on the inner frame. Both the front cover plate and the rear cover plate are provided with a stitch positioning structure. There are two concentric annular protrusions on the inner side of the front cover plate, and the space between the two annular protrusions matches the outer contour of the circular fabric layer of the brake disc preform. The ventilation hole positioning device can be inserted into the card slot on the annular protrusion to fix the position of the support rib without deviation. Guide rails and guide grooves are respectively arranged on both sides of the inner frame and the outer frame, and they are closely matched to effectively control the frame during the stitching process, prevent any shaking, and ensure the accuracy and stability of the stitching work.

[0010] Furthermore, the six-axis stitching robotic arm has six rotating joints and can achieve flexible movement with multiple degrees of freedom to adapt to the stitching trajectory of complex curved surfaces. The robotic arm body is connected by a high-precision reducer, a servo motor, and a control system, and each joint is connected by a sturdy mechanical connection structure to ensure the stability and accuracy of the movement. The six-axis stitching robotic arm is installed on a base to ensure that the robotic arm can perform stitching operations at a suitable position and height.

[0011] Furthermore, the stitching end effector is a fine stitching jaw, and the jaw is connected to the end flange of the robotic arm. The opening and closing of the jaw are controlled by a pneumatic or electric drive method to achieve precise clamping and release of the stitching needle.

[0012] Furthermore, a notch matching the size of the horizontal rod at the top of the inner frame is provided at the top of the outer frame. The inner frame can be directly and precisely inserted into the notch, and then the upper locking screw is tightened to quickly complete the assembly of the stitching tooling.

[0013] Furthermore, the stitch positioning structure is a stitch groove provided with a number of stitch holes. The diameter of the stitch holes is slightly larger than the width of the stitch groove, and the stitch holes are designed in a circular shape, so that the stitching needle can pass through more smoothly during stitching, facilitating the stitching operation.

[0014] Furthermore, the positioning pin holes on the front cover plate match the positioning pins on the rear cover plate, and the two are diagonally distributed to fix the position of the cover plate without deviation. The front cover plate and the inner frame are connected and fixed by locking screws.

[0015] The preparation method of the above-mentioned preform includes the following steps:

[0016] S1. Prepare materials: Prepare nylon binding threads, carbon fiber layup main threads, carbon fiber N-shaped suture threads, base fabric, and sewing needles.

[0017] S2. Lay and sew the surface friction layer: Draw the fiber placement trajectory of the surface friction layer on the Welcome ES V5 software, and import the trajectory into the RPCE carbon fiber sewing machine; Place and fix the base fabric with a width of 1*1m, select the starting embroidery point outside the limit range of the sewing machine, lay the carbon fiber layup main thread along the predetermined trajectory, and the sewing needle drives the nylon binding thread to fix the position of the carbon fiber layup main thread without change. The stitch pitch is set to 11mm, and the needle is automatically locked after sewing.

[0018] S3. Lay and sew the in-plane load-bearing layer: Draw the fiber placement trajectories of the 0° load-bearing layer and the 90° load-bearing layer on the Welcome ES V5 software, and import them into the RPCE carbon fiber sewing machine; After fixing the base fabric, lay the carbon fiber layup main thread along the predetermined trajectory, and the stitch point pitch is set to 11mm; The 90° load-bearing layer is laid and superimposed on the 0° load-bearing layer. First, mark the starting embroidery point of the 0° load-bearing layer, and the starting embroidery point of the 90° load-bearing layer is obtained by rotating the starting embroidery point of the 0° load-bearing layer by 90° and marked. Swing the nylon binding thread around the carbon fiber layup main thread left and right and bind it.

[0019] S4. Lay and sew the unit layer of the support ribs: Draw the fiber placement trajectories of the circumferential fan layer and the radial fan layer on the Welcome ES V5 software, and import them into the RPCE carbon fiber sewing machine; Fix the base fabric. The radial fan layer and the circumferential fan layer are alternately and closely arranged to form a large annular area. First, complete the laying of the radial fan layer and then superimpose the circumferential fan layer on its surface, and alternately superimpose to the specified number of layers; Select the starting embroidery point outside the limit range of the sewing machine, lay the carbon fiber layup main thread along the predetermined trajectory, the stitch point pitch is set to 4mm, and use the nylon binding thread to sew and fix the carbon fiber layup main thread.

[0020] S5. Numerical control cutting: Use the Lectra VectorAuto iX6 type CNC mechanical cutting machine to perform digital cutting of the surface friction layer, in-plane load-bearing layer, and ventilation hole functional layer; After fixing the base fabric on the platform, the CNC mechanical cutting machine performs material contour calibration through a laser scanner, uses a φ3.2mm wave-edge tool to perform cutting at a cutting speed of 12m / min, sets the cutting pressure to 2.5bar, controls the cutting tolerance within the range of ±0.15mm, and obtains the unit preform fabric of the surface friction layer, in-plane load-bearing layer, and ventilation hole functional layer after cutting.

[0021] S6, N-shaped stitching: An automated stitching and forming process is carried out using a dual robotic arm stitching device. The stitching process includes S6-1 material layup and clamping, firmly clamping the preform fabric obtained in S5 in the stitching tooling, being in a state ready for stitching operation; S6-2 stitching and forming, two robotic arms simulate the stitching process of a worker's left and right hands to operate the stitching needle for N-shaped stitching.

[0022] S7, Remove the cover plates: After stitching is completed, remove the front cover plate and the rear cover plate, and take out the prepared brake disc preform.

[0023] Further, the specific steps of S6-1 are as follows: T1 Lay the upper surface friction layer. In the plane, connect and fix the front cover plate and the inner frame using locking screws, place the upper surface friction layer flat on the front cover plate, and ensure its precise alignment with the edge of the front cover plate; T2 Lay the upper in-plane load-bearing layer, making it closely adhere to the upper surface friction layer, and ensure that the fiber direction of the 0° load-bearing layer is parallel to the upper and lower edges of the front cover plate, and the fiber direction of the 90° load-bearing layer is parallel to the left and right edges of the front cover plate;

[0024] T3 Lay the support ribs. First, install the ventilation hole positioning device and accurately snap it into the slot position of the annular protrusion inside the front cover plate to precisely position the support ribs of the ventilation hole functional layer. Then, stack several unit layers in the space between two adjacent ventilation hole positioning devices to form the support ribs, ensuring that they are close to the ventilation hole positioning device; after placement, take out the ventilation hole positioning device; T4 Lay the lower in-plane load-bearing layer, and also ensure that its fiber direction is parallel to the 0° load-bearing layer and the 90° load-bearing layer in the upper in-plane load-bearing layer respectively; T5 Lay the lower surface friction layer, ensuring that it is flat and aligned with the edge of the front cover plate;

[0025] T6 Assemble the stitching tooling. After completing the above steps, snap the rear cover plate onto the front cover plate and fix the rear cover plate to the inner frame with bolts; ensure that the positioning pins on the rear cover plate accurately insert into the positioning pin holes of the front cover plate to fix the position of the cover plates and prevent the preform from shifting during subsequent work; finally, when tightening the bolts, it is necessary to strictly operate in a specific order and torque, which can not only ensure the tight connection between the cover plates and the inner frame, but also avoid applying excessive pressure to the preform or causing its deformation, thereby ensuring the stability and reliability of the entire structure. Snap the inner frame that has completed the planar assembly into the outer frame. The guiding slide rails of the inner frame match the guiding slots of the outer frame to ensure that the inner frame can be smoothly snapped in; after snapping in, tighten the locking screws at the upper end of the outer frame to tightly connect the inner frame and the outer frame, complete the assembly of the entire stitching tooling, and firmly clamp the preform fabric obtained in S5 in the stitching tooling, being in a state ready for stitching operation.

[0026] Further, S6-2 is specifically M1 suture preparation. Thread 2 strands of 3K carbon fiber filaments through a suture needle (Shuangyan brand 120-072) to form an N-shaped suture thread, and pre-store it in a wire storage box. At the ends of two Kawasaki robotic arms a and b with model RS030N, assemble delicate suture jaws a and b respectively. The jaws are debugged to accurately control the suture force and direction, preventing damage to the preform or loose sutures during the suture process. Import the programmed robotic arm suture program, and turn on the machine after completing the above work. M2 suture start: Robotic arm a uses jaw a to hold the suture needle, and according to the set suture trajectory, passes the needle through the suture positioning structure on the suture tooling and transfers it to the other robotic arm b. The two robotic arms cooperate, and according to the suture positioning structure on the cover plate, advance from left to right in sequence according to the suture points, simulating the suture process of the worker's left and right hands, and performing N-shaped suture; realize continuous feeding operation through the preset movement path. Whenever a row of suture operations is completed and a line change is required, cut the N-shaped suture thread.

[0027] M3 regional suture: During the suture process, the preform is sutured according to the robotic arm suture program. In the first stage, control the robotic arm to complete the suture of the upper half area of the preform according to the program-set path; when it is detected that the sutures in the upper half area are completed, the system automatically triggers a reverse return command, and the robotic arm then performs the suture process of the lower half area along the planned path. At the same time, the robotic arm needs to maintain a stable movement speed and force to ensure uniform suture thread tension, so that the structure of the sutured preform is tight and firm.

[0028] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0029] 1. The brake disc preform in the present invention is near-net-shaped, greatly reducing raw material waste.

[0030] 2. The surface friction layer of the brake disc preform in the present invention is spiral. During braking, the spiral fibers are consistent with the tangential direction of the braking force, effectively enhancing the braking force during the braking process and significantly reducing the friction and wear of the brake disc.

[0031] 3. The in-plane load-bearing layer of the brake disc preform in the present invention adopts a load-bearing layer laminate design with 0° / 90° fiber orientation. The fiber combination laid alternately at 0° / 90° effectively ensures the uniform distribution of long fibers in all directions in the load-bearing layer, is simple and efficient to lay, and at the same time ensures that the preform has excellent load-bearing performance in all directions.

[0032] 4. The ventilation hole functional layer of the brake disc preform in the present invention is formed by fan-shaped layer paving with radial / circular fiber orientation, and the process is simple and efficient.

[0033] 5. In the present invention, the brake disc preform uses N-shaped stitching instead of needling. The carbon fibers in the preform are continuous and have good mechanical properties, greatly improving the in-plane properties, interlayer properties and impact resistance of the preform, and achieving high load-bearing capacity.

[0034] 6. When preparing the brake disc preform in the present invention, double robotic arms are used to cooperate for stitching and forming. The tension of the stitching thread is controllable, greatly improving the automation degree and forming quality, and reducing the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a three-dimensional schematic diagram of the structure of the near-net-size brake disc preform;

[0036] Figure 2 is a schematic diagram of the principle of variable-angle traction and stitching technology;

[0037] Figure 3 is a schematic diagram of the laying of the surface friction layer;

[0038] Figure 4 is a schematic diagram of the laying of the in-plane load-bearing layer;

[0039] Figure 5 is a schematic diagram of the laying of the ventilation hole functional layer;

[0040] Figure 6 is a schematic diagram of the layout and cutting of each unit layer of the preform;

[0041] Figure 7 is Figure 6 the schematic sectional view A-A in

[0042] Figure 8 is Figure 6 the schematic sectional view B-B in

[0043] Figure 9 is a three-dimensional schematic diagram of the stitching tooling;

[0044] Figure 10 is a disassembled structure schematic diagram of the stitching tooling;

[0045] Figure 11 is a schematic diagram of the preform clamping process;

[0046] Figure 12 is a schematic diagram of the N-shaped stitching trajectory planning;

[0047] Figure 13 is a schematic diagram of the double robotic arm stitching cooperation;

[0048] Figure 14 is a sectional schematic diagram of the N-shaped stitching process;

[0049] In the figure, 1 - nylon binding thread; 2 - main carbon fiber ply thread; 3 - sewing needle; 4 - base fabric; 5 - N-shaped suture; 6 - guiding device; 7 - upper surface friction layer; 8 - in-plane load-bearing layer; 9 - lower surface friction layer; 10 - ventilation hole functional layer; 11 - ventilation hole; 12 - support rib; 13 - 0° load-bearing layer; 14 - 90° load-bearing layer; 15 - circumferential sector layer; 16 - radial sector layer;

[0050] 17 - sewing tooling; 18 - inner frame; 1801 - guiding slide rail; 19 - outer frame; 1901 - notch; 1902 - guiding card slot; 20 - front cover plate; 2001 - positioning pin hole; 2002 - annular protrusion; 2003 - front cover plate suture positioning structure; 21 - rear cover plate; 2101 - positioning pin; 2102 - rear cover plate suture positioning structure; 22 - ventilation hole positioning device;

[0051] 23 - sewing track; 24 - robotic arm a; 25 - robotic arm b; 26 - T-slot platform; 27 - jaw a; 28 - jaw b; 29 - base; 30 - sewing needle; 31 - locking screw; 32 - bolt; 33 - CNC mechanical cutting machine. Specific embodiments

[0052] To further disclose the content, features and effects of the present invention, the following examples are specifically given and described in detail with reference to the accompanying drawings. In the description of the following embodiments, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing this patent and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to this patent.

[0053] In the description of the following embodiments, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", "connection", "setting" should be understood in a broad sense. For example, it can be fixedly connected and set, or detachably connected and set, or integrally connected and set. For those of ordinary skill in the art, the specific meanings of the above terms in this patent can be understood according to specific circumstances.

[0054] A near-net-size high-load brake disc preform, refer to the attached Figures 1-5, including a surface friction layer, an in-plane bearing layer 8 and a ventilation hole functional layer 10 sewn and fixed by an N-shaped suture line 5, the surface friction layer and the in-plane bearing layer 8 are both annular; the fiber laying trajectory of the surface friction layer is spiral and the surface friction layer is divided into an upper surface friction layer 7 and a lower surface friction layer 9; the fiber laying trajectory of the in-plane bearing layer 8 is linear, and consists of a 0° bearing layer 13 and a 90° bearing layer 14; an upper in-plane bearing layer is provided on the inner side of the upper surface friction layer 7, a lower in-plane bearing layer is provided on the inner side of the lower surface friction layer 9, and a ventilation hole functional layer 10 is provided between the two in-plane bearing layers 8; the ventilation hole functional layer 10 is composed of ventilation holes 11 and support ribs 12 alternately arranged along a circular ring, and the support ribs 12 are composed of unit layers formed by alternating radial fan-shaped layers 16 and annular fan-shaped layers 15, and several of the unit layers are stacked from bottom to top to form support ribs 12.

[0055] A suturing device and suturing operation process, see attached Figures 9-13 , including two six-joint suturing robot arms with suturing end effectors and a suturing workbench, the suturing workbench includes a suturing tool 17 and a T-slot platform 26, the suturing tool 17 is installed on the top surface of the T-slot platform 26; the suturing tool 17, such as Figure 9 As shown, it is composed of five parts: a front cover 20, a rear cover 21, a ventilation hole positioning device 22, an inner frame 18, and an outer frame 19; the front cover 20 and the rear cover 21 are symmetrically distributed and installed on the inner frame 18, and the front cover 20 and the rear cover 21 are respectively provided with a front cover suture positioning structure 2003 and a rear cover suture positioning structure 2102, and the suture positioning structure is a suture groove with a plurality of suture holes, the diameter of the suture hole is slightly larger than the width of the suture groove, and the suture hole adopts a circular design, so that the suture needle 30 can pass through more smoothly, which is convenient for suture operation. The suture operation trajectory is shown as follows Figure 12 shown.

[0056] like Figure 10 As shown, the inner side of the front cover plate 20 is provided with two concentric annular protrusions 2002, and the space between the two annular protrusions 2002 matches the annular fabric layer of the preform; the ventilation hole positioning device 22 can be snapped into the slot on the annular protrusion 2002 to fix the position of the support rib 12 without deviation; the inner frame 18 and the outer frame 19 are respectively provided with a guide rail 1801 and a guide slot 1902 on both sides, which are tightly matched and can effectively control the frame during the sewing process, preventing it from shaking and ensuring the accuracy and stability of the sewing work. The positioning pin hole 2001 on the front cover plate 20 matches the positioning pin 2101 on the rear cover plate 21, and the two are diagonally distributed to fix the position of the cover plate without deviation.

[0057] like Figure 11As shown, the front cover plate 20 and the inner frame 18 are connected and fixed by locking screws 31. A notch 1901 matching the size of the horizontal rod at the top of the inner frame 18 is provided at the top of the outer frame 19. The inner frame 18 can be directly and precisely inserted into the notch 1901. Then, by tightening the upper locking screws 31, the assembly of the sewing tooling 17 can be quickly completed.

[0058] As Figure 13 shown, the six-axis sewing robot arm has six rotating joints and can achieve flexible movement with multiple degrees of freedom to adapt to the sewing trajectories of complex curved surfaces. The robot arm body is composed of a high-precision speed reducer, a servo motor, and a control system connected together. Each joint is connected by a strong mechanical connection structure to ensure the stability and accuracy of the movement. The six-axis sewing robot arm is installed on the base 29 to ensure that the robot arm can perform sewing operations at a suitable position and height. The sewing end effector is a delicate sewing gripper. The gripper a 27 is connected to the end flange of the robot arm a 24, and the gripper b 28 is connected to the end flange of the robot arm b 25. The opening and closing of the gripper a 27 and the gripper b 28 are controlled by a pneumatic or electric drive method to achieve precise clamping and release of the sewing needle 30.

[0059] Refer to the appendix Figures 1-14 , a preparation method for a near-net-size high-load brake disc preform, uses the above sewing device to prepare a preform structure as Figure 1 shown, including the following steps:

[0060] S1. Prepare materials; prepare nylon binding thread 1, carbon fiber main laying thread 2 made of carbon fiber, carbon fiber N-shaped sewing thread 5, base cloth 4, and sewing needle 3; the nylon binding thread 1 is made of polyamide fiber (nylon) with a specification of 150D / 2 strands and a diameter of 0.16 mm; the carbon fiber main laying thread 2 selects 12K PAN-based carbon fiber filaments with a specification of T700SC-12000; the carbon fiber N-shaped sewing thread 5 selects two strands of 3K PAN-based carbon fiber filaments; the sewing needle 3 selects Groz DB×1 gold needle No. 11; the base cloth 4 has a specification of 8 g / m 2 .

[0061] S2. Lay and sew the surface friction layer; draw the fiber laying trajectory of the surface friction layer on the Welcome ES V5 software, and import the trajectory into the RPCE carbon fiber sewing machine. The working principle of the sewing machine is as Figure 2As shown; the core lies in achieving the positioning and placement of carbon fibers through the synchronous laying-stitching process. The guiding device 6 guides the main carbon fiber laying line 2 to be precisely laid on the base fabric along a predetermined trajectory. At the same time, the sewing needle 3 drives the nylon binding thread 1 to perform left-right binding stitching on the main carbon fiber laying line 2, and fixes the main carbon fiber laying line 2 through a chain stitch; Place and fix the base fabric 4 with a width of 1*1m, select the starting embroidery point outside the limit range of the laying and sewing machine, the main carbon fiber laying line 2 is laid along the predetermined trajectory, and the position of the main carbon fiber laying line 2 is fixed with the nylon binding thread 1 without change. The stitch spacing is set to 11mm, and the needle is automatically locked after the laying and sewing is completed; The fiber laying trajectory of the surface friction layer is spiral, as Figure 3 shown;

[0062] S3. Laying and sewing of the in-plane load-bearing layer; Draw the fiber laying trajectories of the 0° load-bearing layer 13 and the 90° load-bearing layer 14 on the Welcome ES V5 software and import them into the RPCE carbon fiber laying and sewing machine; After fixing the base fabric 4, the main carbon fiber laying line 2 is laid along the predetermined trajectory as Figure 4 shown, and the stitch point spacing is set to 11mm; The laying of the 90° load-bearing layer 14 is superimposed on the 0° load-bearing layer 13. First, mark the starting embroidery point of the 0° load-bearing layer 13. The starting embroidery point of the 90° load-bearing layer 14 is obtained by rotating the starting embroidery point of the 0° load-bearing layer 13 by 90° and marked. The nylon binding thread 1 swings left and right around the main carbon fiber laying line 2 and binds it;

[0063] S4. Laying and sewing of the unit layer of the support rib 12; Draw the fiber laying trajectories of the circumferential sector layer 15 and the radial sector layer 16 on the Welcome ES V5 software and import them into the RPCE carbon fiber laying and sewing machine; Fix the base fabric 4. The radial sector layer 16 and the circumferential sector layer 15 are alternately and closely arranged to form a large annular area. First, complete the laying of the radial sector layer 16 and then superimpose the circumferential sector layer 15 on its surface, and alternately superimpose to the specified number of layers, as Figure 5 shown; Select the starting embroidery point outside the limit range of the laying and sewing machine, the main carbon fiber laying line 2 is laid along the predetermined trajectory, the stitch point spacing is set to 4mm, and the main carbon fiber laying line 2 is stitched and fixed with the nylon binding thread 1;

[0064] S5. Numerical control cutting; Use the Lectra VectorAuto iX6 type CNC mechanical cutting machine 33 to perform digital cutting on the surface friction layer, the in-plane load-bearing layer 8 and the ventilation hole functional layer 10, as Figure 6As shown, the spiral surface friction layer, each group of 0° bearing layers 13, 90° bearing layers 14, radial fan-shaped layers 16, and circumferential fan-shaped layers 15 are cut; after the base fabric 4 is fixed on the platform, the CNC mechanical cutting machine 33 calibrates the material profile through a laser scanner, and uses a φ3.2mm waveform edge tool to perform cutting at a cutting speed of 12m / min. The cutting pressure is set to 2.5bar, and the incision tolerance is controlled within the range of ±0.15mm. After cutting, a unit preform fabric of the surface friction layer, in-plane bearing layer 8, and ventilation hole functional layer 10 is obtained; the cross-sectional structure of the in-plane bearing layer 8 is as Figure 7 shown, and the cross-sectional structure of the unit layer of the support rib 12 after cutting is as Figure 8 shown;

[0065] S6. N-shaped stitching; an automated stitching and forming process is carried out using a dual robotic arm stitching device. The stitching process includes S6-1 material layering and clamping, and S6-2 stitching and forming;

[0066] The specific steps of S6-1 are as follows: T1 lays the upper surface friction layer 7, and in the plane, connects and fixes the front cover plate 20 and the inner frame 18 using locking screws 31. Place the upper surface friction layer 7 flat on the front cover plate 20, ensuring its precise alignment with the edge of the front cover plate 20; T2 lays the upper in-plane bearing layer, making it closely fit on the upper surface friction layer 7, and ensuring that the fiber direction of the 0° bearing layer 13 is parallel to the upper and lower edges of the front cover plate 20, and the fiber direction of the 90° bearing layer 14 is parallel to the left and right edges of the front cover plate 20; T3 lays the support rib 12. First, install the ventilation hole positioning device 22 and accurately snap it into the slot position of the annular protrusion 2002 inside the front cover plate 20 to accurately position the support rib 12 of the ventilation hole functional layer 10. Then, stack several unit layers in the space between two adjacent ventilation hole positioning devices 22 to form the support rib 12, ensuring that it is close to the ventilation hole positioning device 22; after placement, remove the ventilation hole positioning device 22; T4 lays the lower in-plane bearing layer, also ensuring that its fiber direction is parallel to the 0° bearing layer 13 and 90° bearing layer 14 in the upper in-plane bearing layer respectively; T5 lays the lower surface friction layer 9, ensuring its flatness and alignment with the edge of the front cover plate 20; T6 assembles the stitching tooling 17, after completing the above steps, snap the rear cover plate 21 onto the front cover plate 20, and fix the rear cover plate 21 to the inner frame 18 through bolts 32; ensure that the positioning pin 2101 on the rear cover plate 21 accurately inserts into the positioning pin hole 2001 of the front cover plate 20 to fix the position of the cover plate and prevent the preform from shifting during subsequent work; finally, when tightening the bolts 32, it is necessary to strictly operate in a specific order and torque, which can not only ensure the tight connection between the cover plate and the inner frame, but also avoid applying excessive pressure to the preform or causing its deformation, thereby ensuring the stability and reliability of the entire structure. The assembly process is as Figure 11As shown in the figure. The inner frame 18 that has completed the planar assembly is snapped into the outer frame 19. The guiding slide rail 1801 of the inner frame 18 matches the guiding slot 1902 of the outer frame 19 to ensure that the inner frame 18 can be smoothly snapped in. After snapping in, tighten the locking screw 31 at the upper end of the outer frame 19 to tightly connect the inner frame 18 and the outer frame 19, completing the assembly of the entire stitching tooling 17. The prefabricated fabric obtained in S5 is firmly clamped in the stitching tooling 17 and is in a state waiting for the stitching operation.

[0067] The specific content of S6-2 is M1 stitching preparation. Thread 2 strands of 3K carbon fiber filaments onto the stitching needle 30 (Double Swallow brand 120-072) to form an N-shaped stitching thread 5 and pre-store it in the thread storage box. At the ends of two Kawasaki robotic arms a24 and b25 of model RS030N, assemble delicate stitching jaws a27 and b28. After debugging, the jaws can precisely control the stitching force and direction to prevent damage to the preform or loose stitching during the stitching process. Import the programmed robotic arm stitching program and power on after completing the above work. M2 stitching starts. The robotic arm a24 uses the jaw a27 to hold the stitching needle 30 and, according to the set stitching trajectory, passes the needle through the slot holes on the stitching tooling 17 and transfers it to the other robotic arm b25. The two robotic arms cooperate and advance sequentially according to the stitching points from left to right according to the front cover plate stitching positioning structure 2003 and the rear cover plate stitching positioning structure 2102, as Figure 13 shown, simulating the stitching process of the worker's left and right hands, as Figure 14 shown for N-shaped stitching; achieve continuous feeding operation through the preset movement path. Whenever a row of stitching operations is completed and a line change is required, cut the N-shaped stitching thread. M3 regional stitching. During the stitching process, the preform is stitched according to the robotic arm stitching program. In the first stage, control the robotic arm to complete the stitching of the upper half area of the preform according to the program-set path. When it is monitored that the stitching of the upper half area is completed, the system automatically triggers a reverse return command, and the robotic arm then performs the stitching process of the lower half area along the planned path 23, as Figure 12 shown. At the same time, the robotic arm needs to maintain a stable movement speed and force to ensure uniform tension of the stitching thread, so that the structure of the stitched preform is tight and firm.

[0068] S7. Remove the cover plates; after stitching is completed, remove the front cover plate 20 and the rear cover plate 21, and take out the prepared brake disc preform. The overall structure of the brake disc preform is as Figure 1 shown.

[0069] Example 1: A near-net-size high-load brake disc preform has an outer diameter of 350 mm, an inner diameter of 75 mm, and a thickness of 45 mm. This preform uses the variable-angle tow placement technology (TFP) and is processed using an RPCE carbon fiber placement machine. The machine needle 3 is a Grotz DB×1 gold needle No. 11, and the specification of the base fabric 4 is 8 g / m 2 , the specification of the carbon fiber filaments of the carbon fiber ply main line 2 is 4-ply 12K (the thickness of a single-layer fabric for placement is 2.5 mm), and the specification of the nylon binding thread 1 is 150D / 2. The N-shaped stitching uses a 2-ply 3K carbon fiber N-shaped stitching thread 5, and the stitching pitch is 5 mm.

[0070] Prepare a spiral surface friction layer in accordance with S2, which are respectively used as the upper surface friction layer 7 and the lower surface friction layer 9 of the brake disc; prepare a 0° load-bearing layer 13 and a 90° load-bearing layer 14 in accordance with S3; prepare a radial sector layer 16 and a circumferential sector layer 15 in accordance with S4. Place all the above fabrics on the cutting table and perform numerical control cutting in accordance with S5. Place the cut preform fabric into the inner frame 18 of the stitching tooling 17 and fix it according to the ply clamping step S6-1 to complete the assembly of the stitching tooling 17, so that the preform is firmly clamped in the stitching tooling 17 and in a state suitable for stitching operations. Subsequently, in accordance with the N-shaped stitching sequence in S6-2, prepare the N-shaped stitching thread 5, the stitching needle 30, and the stitching program, import the program into the robotic arm about to operate, and start the robotic arm a24 and the robotic arm b25 to make them complete the stitching operation of the preform according to the predetermined program. After stitching is completed, remove the front cover plate 20 and the rear cover plate 21 of the stitching tooling, and this near-net-size high-load brake disc preform can be obtained.

[0071] Example 2: A near-net-size high-load brake disc preform, the specification of the carbon fiber filaments of the carbon fiber ply main line 2 is 2-ply 12K (the thickness of a single-layer fabric for placement is 1.5 mm)). The N-shaped stitching uses a 2-ply 6K carbon fiber N-shaped stitching thread 5, and the stitching pitch is 10 mm. Other structures, parameters, and preparation processes are basically the same as those in Example 1.

[0072] Although the preferred embodiments of the present invention are described above, the present invention is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many forms without departing from the spirit of the present invention and the scope protected by the claims. All of these fall within the protection scope of the present invention.

Claims

1. A near-net-size high-load brake disc preform, characterized in that: It includes a surface friction layer, an in-plane load-bearing layer, and a ventilation hole functional layer fixed by an N-shaped suture. Both the surface friction layer and the in-plane load-bearing layer are circular rings. The fiber laying trajectory of the surface friction layer is spiral, and the surface friction layer is divided into an upper surface friction layer and a lower surface friction layer. The in-plane load-bearing layer is composed of a 0° load-bearing layer and a 90° load-bearing layer. An upper in-plane load-bearing layer is provided inside the upper surface friction layer, and a lower in-plane load-bearing layer is provided inside the lower surface friction layer. A ventilation hole functional layer is provided between the two in-plane load-bearing layers. The ventilation hole functional layer is composed of ventilation holes and support ribs alternately arranged along the circular ring. The support ribs are composed of unit layers alternately sewn by radial fan-shaped layers and circumferential fan-shaped layers. A plurality of the unit layers are stacked from bottom to top to form the support ribs.

2. A stitching device for preparing the brake disc preform as described in claim 1, comprising two six-axis stitching robotic arms equipped with stitching end effectors and a stitching workbench, characterized in that: The sewing workbench includes a sewing tooling and a T-slot platform. The sewing tooling is installed on the top surface of the T-slot platform. The sewing tooling is composed of five parts: a front cover plate, a rear cover plate, a ventilation hole positioning device, an inner frame, and an outer frame. The front cover plate and the rear cover plate are symmetrically distributed and installed on the inner frame. Sewing line positioning structures are provided on both the front cover plate and the rear cover plate. Two concentric annular protrusions are provided inside the front cover plate. The space between the two annular protrusions matches the outer contour of the circular fabric layer of the brake disc preform. The ventilation hole positioning device can be inserted into the card slot on the annular protrusion. Guide sliding rails and guide card slots are respectively provided on both sides of the inner frame and the outer frame, and the two are closely matched.

3. The suturing device according to claim 2, wherein: The six-joint sewing robotic arm has six rotating joints, and each joint is connected by a mechanical connection structure. The six-joint sewing robotic arm is installed on a base.

4. The suture device according to claim 2, characterized in that: The sewing end effector is a sewing jaw, and the jaw is connected to the end flange of the robotic arm. The opening and closing of the jaw are controlled by a pneumatic or electric drive method to realize the clamping and release of the sewing needle.

5. The suturing device according to claim 2, wherein: A notch matching the size of the horizontal rod at the top of the inner frame is provided at the top of the outer frame. The inner frame can be directly inserted into the notch, and the assembly of the sewing tooling can be completed by tightening the upper locking screw.

6. The suture device according to claim 2, wherein: The sewing line positioning structure is a sewing line groove provided with a plurality of sewing line holes. The diameter of the sewing line holes is slightly larger than the width of the sewing line groove, and the sewing line holes are designed in a circular shape.

7. The suture device according to claim 2, wherein: The positioning pin holes on the front cover plate match the positioning pins on the rear cover plate, and the two are diagonally distributed. The front cover plate and the inner frame are connected and fixed by locking screws.

8. A preparation method of a near-net-size high-load brake disc preform, using the stitching device according to any one of claims 2-7, characterized in that, It includes the following steps: S1. Prepare materials; Prepare nylon binding wires, carbon fiber laying main lines, carbon fiber N-shaped sutures, base cloth, and sewing needles. S2. Sew the surface friction layer; Draw the fiber laying trajectory of the surface friction layer on software and import the trajectory into the RPCE carbon fiber sewing machine. Place and fix the base cloth, select a starting embroidery point outside the limit range of the sewing machine, lay the carbon fiber laying main line according to the predetermined trajectory, and the sewing needle drives the nylon binding wire to sew and fix the carbon fiber laying main line. The stitch pitch is set to 11 mm, and the needle is automatically locked after sewing. S3. In-plane load-bearing layer sewing: Draw the fiber placement trajectories of the 0° load-bearing layer and the 90° load-bearing layer on software, and import them into the RPCE carbon fiber sewing machine. After fixing the base fabric, the main carbon fiber laying line is laid according to the predetermined trajectory, and the spacing of the stitch points is set to 11 mm. The 90° load-bearing layer is laid on top of the 0° load-bearing layer. First, mark the starting point of the 0° load-bearing layer. The starting point of the 90° load-bearing layer is obtained by rotating the starting point of the 0° load-bearing layer by 90° and marked. Use a nylon binding line to swing left and right around the main carbon fiber laying line and bind it. S4. Unit layer sewing of support ribs: Draw the fiber placement trajectories of the circumferential sector layer and the radial sector layer on software, and import them into the RPCE carbon fiber sewing machine. Fix the base fabric. The radial sector layer and the circumferential sector layer are alternately and closely arranged to form a large annular area. First, complete the laying of the radial sector layer and then stack the circumferential sector layer on its surface, alternately stacking to the specified number of layers. Select a starting point outside the limit range of the sewing machine, and the main carbon fiber laying line is laid according to the predetermined trajectory. The spacing of the stitch points is set to 4 mm, and a nylon binding line is used to stitch and fix the main carbon fiber laying line. S5. CNC cutting: Use a CNC mechanical cutting machine to perform digital cutting of the surface friction layer, in-plane load-bearing layer, and ventilation hole functional layer. After fixing the base fabric on the platform, the CNC mechanical cutting machine calibrates the material contour through a laser scanner, and after cutting, unit prefabricated fabrics of the surface friction layer, in-plane load-bearing layer, and ventilation hole functional layer are obtained. S6. N-shaped sewing: Use a double robotic arm sewing device for automated sewing and forming. The sewing process includes S6-×××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××× ​ ​ 9. The preparation method of the near-net-size high-load brake disc preform according to claim 8, characterized in that: The specific steps of S6-1 are as follows: T1: Lay the friction layer on the upper surface. Connect and fix the front cover plate and the inner frame in the plane using locking screws. Place the friction layer on the upper surface of the front cover plate flatly, ensuring that it is aligned with the edge of the front cover plate. T2: Lay the inner load-bearing layer on the upper surface, making it closely fit on the friction layer on the upper surface. Ensure that the fiber direction of the 0° load-bearing layer is parallel to the upper and lower edges of the front cover plate, and the fiber direction of the 90° load-bearing layer is parallel to the left and right edges of the front cover plate. T3: Lay the support ribs. First, install the ventilation hole positioning device and accurately snap it into the groove position of the annular protrusion inside the front cover plate. Then, stack several unit layers in the space between two adjacent ventilation hole positioning devices to form the support ribs, ensuring that they are close to the ventilation hole positioning device. After placing, remove the ventilation hole positioning device. T4: Lay the lower inner load-bearing layer, and also ensure that its fiber direction is parallel to the 0° load-bearing layer and 90° load-bearing layer in the upper inner load-bearing layer respectively. T5: Lay the friction layer on the lower surface, ensuring that it is flat and aligned with the edge of the front cover plate. T6: Assemble the sewing tooling. After completing the above steps, snap the rear cover plate onto the front cover plate and fix the rear cover plate to the inner frame. Snap the inner frame that has completed the planar assembly into the outer frame. The guiding slide rail of the inner frame matches the guiding groove of the outer frame. After snapping in, the inner frame and the outer frame are tightly connected to complete the assembly of the sewing tooling. Install the prefabricated fabric obtained in S5 in the sewing tooling, and it is in a state waiting for the sewing operation.

10. The preparation method of the near-net-size high-load brake disc preform according to claim 8, characterized in that: The specific steps of S6-2 are as follows: M1: Sewing preparation. Thread 2 carbon fiber filaments through the sewing needle to form an N-shaped sewing thread and store it in the wire storage box in advance. Assemble the jaws a and b at the ends of the robotic arm a and robotic arm b respectively and debug them. Import the programmed robotic arm sewing program, and then power on after completing the above work. M2: Start sewing. The robotic arm a uses the jaw a to hold the sewing needle. According to the set sewing trajectory, pass the sewing needle through the sewing line positioning structure on the sewing tooling and transfer it to the other robotic arm b. The two robotic arms cooperate to move from left to right and sequentially advance according to the sewing points to perform N-shaped sewing by simulating the sewing process of the left and right hands of a worker. Achieve continuous feeding operation through the preset movement path. Whenever a row of sewing operations is completed and a new row is needed, cut the N-shaped sewing thread. M3: Sew in regions. During the sewing process, in the first stage, control the robotic arm to complete the sewing of the upper half region of the prefabricated body according to the programmed path. When it is detected that the sewing thread in the upper half region is completed, the system automatically triggers a reverse return command, and the robotic arm then executes the sewing process for the lower half region along the planned path.

Images