Three-dimensional braided preform multi-channel densification device and preform braiding method

Abstract

The present invention discloses a three-dimensional braided preform multi-channel densification device, which includes a lifting mechanism, an insertion mechanism, and a rotating mechanism. The rotating mechanism drives the device to rotate to a set angle, and the lifting mechanism controls the downward movement of the insertion mechanism, so that the reed descends to the same horizontal position as the intersection point. The air cylinder extends to drive the small arm rod to swing inward, and the reed at the end of the small arm rod inserts into the yarn interweaving knot below. At the same time, the lifting mechanism drives the insertion mechanism to move upward, and the reed contracts inward while lifting upward, so as to lift the interwoven yarn to the knitting node on the surface of the core mold. Then the air cylinder retracts again, the small arm rod swings outward, the reed disengages from the yarn area, and the rotating platform rotates to the next densification cycle position by a set angle. After multiple cycles, all the interwoven yarns in the circumference are lifted to the predetermined position, and the densification of the yarn is completed. In the three-dimensional braiding process of the present invention, the interwoven yarn is lifted upward for densification treatment.

Description

Technical Field

[0001] The present invention belongs to the field of densification of three-dimensional braided preforms, and particularly relates to a three-dimensional braided preform densification device and method based on a cylinder-link mechanism. Background Art

[0002] Three-dimensional braided composites are a new type of advanced composite material in the high-tech field. Fiber bundles are interwoven in different directions within the material to form an integral structure, which has excellent impact toughness, fatigue resistance, and ablation resistance. It can be used to manufacture high-temperature functional structural materials, and can also be used for components such as beams, frames, ribs, shafts, and rods in structures such as wind turbine blades.

[0003] Currently, the densification methods for the interwoven yarns during three-dimensional braiding are all based on workers holding tools for densification. The tasks are heavy, time-consuming, inefficient, and it is difficult to ensure the uniformity of the flower knots. It is impossible to densify high-thickness and a large number of yarns, resulting in excessive wear of the yarns during the subsequent weaving process of the preform, affecting the mechanical properties of the composite material, and problems such as shape distortion. Summary of the Invention

[0004] Aiming at the problems existing in the prior art, the present invention provides a three-dimensional braided preform densification device based on a cylinder-link mechanism, which uses a machine to complete this cumbersome task, improves the densification efficiency of three-dimensional braided preforms, reduces the labor burden, saves the weaving time. At the same time, a preform weaving method using the three-dimensional braided preform densification device is also provided.

[0005] Technical Solution: The present invention proposes a multi-channel densification device for three-dimensional braided preforms, including a lifting mechanism, a rotating mechanism, and an inserting mechanism; the lifting mechanism drives the inserting mechanism to lift, and the rotating mechanism drives the inserting mechanism to rotate;

[0006] The inserting mechanism includes an annular mounting seat and a plurality of claw mechanisms installed around the mounting seat; each claw mechanism has the same structure, and each includes a cylinder connected to the mounting seat, a small arm hinged to the output end of the cylinder, a reed piece hinged to the bottom of the small arm, and a support rod fixed below the mounting seat and extending outward; the upper end of the support rod is fixed on the mounting seat, the lower end of the support rod is hinged to the small arm, and the hinge point of the support rod and the small arm is lower than the hinge point of the small arm and the cylinder to form a lever structure; a spring is provided at the bottom of the small arm, one end of the spring is installed on the small arm, and the other end of the spring is installed on the reed piece to keep the reed piece in a state of bending inward relative to the small arm; each cylinder output end simultaneously extends or contracts the same distance. When each cylinder output end simultaneously extends, all the reed pieces simultaneously move upward and contract inward.

[0007] Further, the lifting mechanism includes a ball screw extending downward from top to bottom, a servo motor connected to the upper end of the ball screw and driving the ball screw to rotate, and a lifting table; the lifting table is installed on the screw nut of the ball screw, and the middle of the lifting table is hollow to allow the ball screw to pass through.

[0008] Further, the rotating mechanism is a hollow rotating platform; the rotating mechanism is installed at the bottom of the lifting table, and the bottom of the ball screw passes through the hollow part of the hollow rotating platform.

[0009] Further, the mounting seat includes a hollow first mounting ring fixed to the bottom of the hollow rotating platform, a hollow second mounting ring located below the first mounting ring, and a hollow third mounting ring located below the second mounting ring; the first mounting ring and the second mounting ring, and the second mounting ring and the third mounting ring are all connected by connecting rods; the tail end of the cylinder is hinged to the second mounting ring, and the support rod is fixed to the third mounting ring and extends obliquely downward outward from the third mounting ring.

[0010] The present invention also provides a preform weaving method using the above three-dimensional woven preform multi-channel densification device, including the following steps:

[0011] (1) Lowering stage: The core mold 4 and the mounting seat are coaxially placed, and the core mold is located at the central position of a plurality of jaw mechanisms. The insertion mechanism is driven by the rotating mechanism to rotate to a set angle. At this time, the intersection point of the insertion mechanism and the carbon fiber yarn is in the same vertical plane. The lifting mechanism controls the insertion mechanism to move downward, and the cylinder of the insertion mechanism retracts until the reed descends to the same horizontal position as the intersection point.

[0012] (2) Lifting stage: The cylinder extends to drive the bottom end of the small arm to swing inward, and the reed inserts into the yarn interweaving knot below; at the same time, the lifting mechanism drives the insertion mechanism to move upward, and the reed contracts inward while lifting upward to lift the interwoven yarn to the weaving node on the surface of the core mold.

[0013] (3) Rotating stage: After the yarn is densely placed in position, the cylinder retracts again, the small arm swings outward, the reed opens, and disengages from the yarn area; the rotating platform rotates to a set angle to the next dense cycle position.

[0014] (4) Repeat steps (1)-(3) until all the interwoven yarns in the circumference are lifted to the predetermined position, and a typical densification process ends.

[0015] Further, step (1) includes the following sub-steps:

[0016] (1.1) The rotating platform rotates to a specified position, and its position should enable the insertion mechanism to avoid the interwoven yarn and accurately extend into the intersection point.

[0017] (1.2) The cylinder of the insertion mechanism contracts to the limit position, and the small arm rotates outward around the hinge of the flaring ring under the drive of the cylinder. At this moment, the insertion mechanism is in the expanded state to avoid the intertwined yarns;

[0018] (1.3) The lifting mechanism drives the insertion mechanism to move downward, and the reed blade extends into the position of the intersection point.

[0019] Furthermore, in step (2):

[0020] The cylinder in the insertion mechanism contracts, and the small arm rotates inward around the hinge of the flaring ring under the drive of the cylinder. The reed blade at the end of the small arm contacts the intersection point and pushes the intersection point inward horizontally to the position of the core mold radius; at the same time, the lifting mechanism drives the insertion mechanism to rise, and the reed blade at the end of the small arm rises. Vertically, the intersection point is pushed upward to the surface of the core mold;

[0021] Among them, the cylinder extends at a constant speed. The rotation arc trajectory and speed of the small arm are obtained through the extension speed of the cylinder. After comparing with the target straight line trajectory, the rotation speed of the servo motor is obtained by numerical differentiation, so that the spatial movement trajectory of the end reed blade is a straight line, and the reed blade can push the intersection point along the straight line.

[0022] The beneficial effects of the present invention: The three-dimensional braided preform densification device and method based on the cylinder connecting rod mechanism of the present invention cooperate with the insertion mechanism and the lifting mechanism, adjust the reed blade angle by using a spring, rotate through a high-precision rotating platform to traverse all intersection points, and densify the intertwined yarns during the three-dimensional braiding process, featuring high quality and high efficiency. The three-dimensional braided preform densification device and method based on the cylinder connecting rod mechanism of the present invention reduce the interference of the proficiency of manual densification workers, improve the densification speed in the preform production process, reduce the working intensity of operators, and can effectively reduce the friction and wear of fiber bundles during the preform braiding process, ultimately ensuring the uniformity of the composite material stitch and mechanical properties. Description of the Drawings

[0023] Figure 1 is the structural schematic diagram of the densification device in the present invention;

[0024] Figure 2 is the flow chart of densification during the braiding process in the present invention;

[0025] Figure 3 is the schematic diagram of the insertion mechanism avoiding yarns in the present invention;

[0026] Figure 4 is the schematic diagram of the insertion point of the insertion mechanism in the present invention;

[0027] Figure 5 is the schematic diagram of the insertion mechanism in the present invention pushing the intertwined yarns to the surface of the core mold;

[0028] Figure 6 This is a schematic structural diagram of the reed blade in the present invention. Specific embodiments

[0029] The present invention will be further described below in conjunction with the accompanying drawings. The following examples are only used to describe the present invention and are not used to limit the scope of use of the present invention. All equivalent transformations of the present invention by those skilled in the art of various fields are included within the scope of the rights required by the present invention.

[0030] As Figure 1 shown, a three-dimensional braided preform multi-channel densification device, characterized in that it includes a lifting mechanism 10, a rotating mechanism 30, and an inserting mechanism 20.

[0031] The inserting mechanism includes an annular mounting seat 204 and a number of claw mechanisms installed around the mounting seat in a circle. Each claw mechanism has the same structure and includes a cylinder 205 connected to the mounting seat 204, a small arm 201 hinged to the output end 2051 of the cylinder, a reed blade 203 hinged to the bottom of the small arm, and a support rod 206 fixed below the mounting seat 204 and extending outwards. The upper end of the support rod 206 is fixed to the mounting seat 204, the lower end of the support rod 206 is hinged to the small arm 201, and the hinge point of the support rod 206 and the small arm 201 is lower than the hinge point of the small arm and the cylinder 205 to form a lever structure. A spring 202 is provided at the bottom of the small arm 201. One end of the spring 202 is installed on the small arm 201, and the other end of the spring 202 is installed on the reed blade 203 to keep the reed blade 203 in a state of being bent inwards relative to the small arm 201.

[0032] Each cylinder output end extends or contracts the same distance simultaneously. As Figure 5 shown, when each cylinder output end extends simultaneously, all the reed blades 203 move upwards and contract inwards simultaneously.

[0033] The lifting mechanism 10 includes a ball screw 102 extending from top to bottom, a servo motor 101 connected to the upper end of the ball screw 102 and driving the ball screw 102 to rotate, and a lifting table 103. The lifting table 103 is installed on the screw nut 104 of the ball screw 102, and the middle of the lifting table 103 is hollow to allow the ball screw 102 to pass through. The rotating mechanism 30 is a hollow rotating platform. The rotating mechanism 30 is installed at the bottom of the lifting table 103, and the bottom of the ball screw 102 passes through the hollow part of the hollow rotating platform. Any commonly used hollow rotating platform in the prior art can be used for the hollow rotating platform, and the purpose is to avoid interference with the ball screw through the hollow position.

[0034] The mounting base 204 includes a hollow first mounting ring fixed to the bottom of the hollow rotating platform, a hollow second mounting ring located below the first mounting ring, and a hollow third mounting ring located below the second mounting ring; the first mounting ring and the second mounting ring, and the second mounting ring and the third mounting ring are connected by connecting rods. The tail end of the cylinder 205 is hinged to the second mounting ring, and the support rod is fixed to the third mounting ring and extends downward obliquely outward from the third mounting ring.

[0035] The steps of the preform weaving method using the three-dimensional braided preform multi-channel densification device are as follows:

[0036] (1) The descending stage, including:

[0037] (1.1) The rotating platform rotates to a specified position, and its position should enable the insertion mechanism to avoid the interwoven yarns and accurately extend into the intersection point.

[0038] (1.2) The cylinder in the insertion mechanism contracts to the limit position, and the small arm rotates and unfolds outward around the hinge point of the flared ring under the drive of the cylinder. At this moment, the insertion mechanism is in an open state to avoid the interwoven yarns.

[0039] (1.3) The lifting mechanism drives the insertion mechanism to move downward, and the reed blade extends into the intersection point position.

[0040] (2) The lifting stage: including:

[0041] The cylinder in the insertion mechanism contracts, and the small arm rotates and contracts inward around the hinge point of the flared ring under the drive of the cylinder. The reed blade at the end of the small arm contacts the intersection point and pushes the intersection point inward to the core mold radius position in the horizontal direction; at the same time, the servo motor in the lifting mechanism reverses, driving the ball screw to make the insertion mechanism rise, and the reed blade at the end of the small arm rises, pushing the intersection point upward to the core mold surface in the vertical direction. After the reed blade withdraws, the densified yarns still cover the core mold surface due to the action of friction and internal extrusion of the yarns.

[0042] In the above steps, the cylinder and the servo motor move simultaneously. The cylinder extends at a constant speed. By obtaining the rotation arc trajectory and speed of the small arm through the cylinder extension speed, comparing it with the target straight line trajectory, and using numerical differentiation to obtain the rotation speed of the servo motor, the spatial movement trajectory of the end reed blade is a straight line, and the reed blade can push the intersection point along the straight line.

[0043] (3) The rotation stage: After the yarns are densely in place, the cylinder retracts again, the small arm swings outward, the reed blade opens, and disengages from the yarn area; the densified yarns still cover the core mold surface due to the action of friction and internal extrusion of the yarns. The rotating platform rotates by a set angle to the next densification cycle position;

[0044] (4) Repeat steps (1)-(3) until all the interwoven yarns on the circumference are lifted to the predetermined position, and a typical densification process ends.

[0045] Through the method of the present invention, the densification of the interwoven yarns in the three-dimensional braiding process can be quickly achieved, realizing high-quality and high-efficiency yarn densification.

[0046] The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the idea of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, several improvements and refinements made without departing from the principle of the present invention should be regarded as within the protection scope of the present invention.

Claims

1. A three-dimensional braided preform multi-channel densification device, characterized in that, it includes a lifting mechanism (10), a rotating mechanism (30), and an inserting mechanism (20); the lifting mechanism drives the inserting mechanism to lift, and the rotating mechanism drives the inserting mechanism to rotate; The inserting mechanism includes an annular mounting seat (204) and a number of claw mechanisms installed around the mounting seat; each claw mechanism has the same structure and includes a cylinder (205) connected to the mounting seat, a small arm (201) hinged to the output end of the cylinder, a reed piece (203) hinged to the bottom of the small arm, and a support rod (206) fixed below the mounting seat and extending outward; the upper end of the support rod is fixed on the mounting seat, the lower end of the support rod is hinged to the small arm (201), and the hinge point of the support rod and the small arm is lower than the hinge point of the small arm and the cylinder (205) to form a lever structure; a spring (202) is provided at the bottom of the small arm (201), one end of the spring is installed on the small arm, and the other end of the spring is installed on the reed piece (203) to keep the reed piece (203) in a state of being bent inward relative to the small arm; The output ends of each cylinder extend or contract the same distance at the same time. When the output ends of each cylinder extend at the same time, all the reed pieces (203) move upward and contract inward at the same time; The lifting mechanism (10) includes a ball screw (102) extending from top to bottom, a servo motor (101) connected to the upper end of the ball screw and driving the ball screw to rotate, and a lifting table (103); the lifting table is installed on the screw nut of the ball screw, and the middle of the lifting table is hollow to allow the ball screw to pass through; The rotating mechanism (30) is a hollow rotating platform; the rotating mechanism (30) is installed at the bottom of the lifting table (103), and the bottom of the ball screw (102) passes through the hollow part of the hollow rotating platform.

2. The three-dimensional braided preform multi-channel densification device according to claim 1, characterized in that, the mounting seat (204) includes a hollow first mounting ring fixed to the bottom of the hollow rotating platform, a hollow second mounting ring located below the first mounting ring, and a hollow third mounting ring located below the second mounting ring; the first mounting ring and the second mounting ring, and the second mounting ring and the third mounting ring are all connected by connecting rods; the tail end of the cylinder (205) is hinged to the second mounting ring, and the support rod is fixed to the third mounting ring and extends downward obliquely outward from the third mounting ring.

3. A preform braiding method using the three-dimensional braided preform multi-channel densification device according to claim 1 or 2, characterized in that, it includes the following steps: (1) Lowering stage: Place the core mold coaxially with the mounting seat, and the core mold is located at the central position of a number of claw mechanisms; the inserting mechanism is driven by the rotating mechanism to rotate to a set angle. At this time, the intersection points of the inserting mechanism and the carbon fiber yarns are in the same vertical plane. The lifting mechanism controls the inserting mechanism to move downward, and the cylinders of the inserting mechanism retract until the reed pieces reach the same horizontal position as the intersection points. (2) Lifting stage: The cylinder extends to drive the bottom end of the small arm to swing inward, and the reed blade inserts into the yarn interweaving knots below; at the same time, the lifting mechanism drives the inserting mechanism to move upward, and the reed blade lifts upward while contracting inward to lift the interwoven yarn to the knitting node on the surface of the core mold; (3) Rotating stage: After the yarn is densely in place, the cylinder retracts again, the small arm swings outward, the reed blade opens, and disengages from the yarn area; the rotating platform rotates by a set angle to the position for the next dense cycle; (4) Repeat steps (1)-(3) until all the interwoven yarns on the circumference are lifted to the predetermined position, and a typical densification process ends.

4. The preform weaving method according to claim 3, characterized in that step (1) includes the following sub-steps: (1.1) The rotating platform rotates to the specified position, and its position should enable the inserting mechanism to avoid the interwoven yarn and accurately extend into the intersection point; (1.2) The cylinder of the inserting mechanism contracts to the limit position, and the small arm rotates and unfolds outward around the hinge of the flared ring under the drive of the cylinder. At this moment, the inserting mechanism is in an open state to avoid the interwoven yarn; (1.3) The lifting mechanism drives the inserting mechanism to move downward, and the reed blade extends into the intersection point position.

5. The preform weaving method according to claim 4, characterized in that in step (2): The cylinder in the inserting mechanism contracts, and the small arm rotates and contracts inward around the hinge of the flared ring under the drive of the cylinder. The reed blade at the end of the small arm contacts the intersection point and pushes the intersection point inward horizontally to the core mold radius position; at the same time, the lifting mechanism drives the inserting mechanism to rise, and the reed blade at the end of the small arm rises. Vertically, the intersection point is pushed upward to the surface of the core mold; Among them, the cylinder extends at a constant speed. By obtaining the rotation arc trajectory and speed of the small arm through the cylinder extension speed, and comparing it with the target straight line trajectory, the rotation speed of the servo motor is obtained by numerical differentiation, so that the spatial movement trajectory of the end reed blade is a straight line, and the reed blade can push the intersection point along the straight line.

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