Thermoplastic carbon fiber forming device and thermoplastic carbon fiber crank

Abstract

The invention relates to the technical field of bicycle manufacturing, in particular to a thermoplastic carbon fiber forming device and a thermoplastic carbon fiber crank. Comprising a fixed mold, a movable mold and an air bag, the fixed mold and the movable mold jointly form a female mold and are jointly used for providing external extrusion force for a carbon fiber prefabricated body, the air bag is used for serving as a male mold and providing internal extrusion force for the carbon fiber prefabricated body, an air storage box is fixedly connected into the air bag, the air storage box is connected with a sealing cover in a sealed mode, and the sealing cover is connected with the movable mold. And the gas storage box and the sealing cover are filled with high-pressure gas. The air bag is pre-embedded in the carbon fiber prefabricated body, so that the air bag, the air storage box in the air bag and the sealing cover jointly apply extrusion force to the interior of the carbon fiber prefabricated body, a preformed hole used for inflating the air bag is not needed, and the crank prefabricated body and the first metal insert and the second metal insert on the crank prefabricated body are integrally formed; and further, the structural integrity of a workpiece formed by the carbon fiber preform is improved.

Description

Technical Field

[0001] The invention relates to the technical field of bicycle manufacturing, and in particular to a thermoplastic carbon fiber molding device and a thermoplastic carbon fiber crank. Background Art

[0002] As the core component of the front sprocket of a bicycle, the crank has the key task of connecting the sprocket to the pedal. In the process of making thermoplastic carbon fiber cranks, workers lay out the carbon fiber sheets pre-impregnated with resin layer by layer to form a crank preform, and pre-embed an inflatable flexible airbag (or a silicone core material that expands when heated) in the crank preform, and reserve mounting holes for metal inserts on the crank preform. The staff places the completed crank preform in the mold and heats it in an oven. After reaching a certain temperature, the staff starts the air pump to inflate the reserved airbag. The airbag applies a uniform expansion force to the crank preform from the inside (if silicone is used, the silicone expands when heated to provide internal pressure to the crank preform), ensuring that the carbon fiber material fits tightly to the mold surface. After a 3-5 hour constant temperature and pressure curing process, the carbon fiber crank is cured and formed. The staff finally removes the carbon fiber crank from the mold. After removal, the airbag (or silicone core material) is taken out through the installation hole of the metal insert, and the metal insert is installed in the carbon fiber crank. However, in this forming method, the junction of the metal insert and the carbon fiber will become the weak link in the stress of the entire crank, resulting in insufficient integrity of the carbon fiber crank and a low ultimate stress value of the carbon fiber crank. However, if the metal insert is embedded in the crank preform so that the metal insert and the carbon fiber crank are formed as one piece, it is necessary to open an additional reserved hole with a diameter of 10 mm to 20 mm on the carbon fiber crank to inflate the reserved airbag (or remove the silicone core material) during the heating process. Although these holes will be repaired with reinforcement sheets later, the reserved holes still cause great damage to the structural integrity of the carbon fiber crank, and will still have a great impact on the strength and life of the carbon fiber crank in actual use. Summary of the invention

[0003] In order to overcome the shortcomings of existing carbon fiber cranks that in order to inflate the reserved airbag during the heating process, a reserved hole is set on the crank preform or a metal insert is installed on the crank preform later, resulting in low strength of the produced carbon fiber crank, the present invention provides a thermoplastic carbon fiber molding device and a thermoplastic carbon fiber crank.

[0004] The technical solution of the present invention is: a thermoplastic carbon fiber forming device, comprising a fixed mold, a movable mold and an airbag, the fixed mold and the movable mold together form a female mold, the two are used together to provide external extrusion pressure to the carbon fiber preform, the airbag is used to act as a male mold to provide internal extrusion pressure to the carbon fiber preform, the fixed mold and the movable mold are both fixedly connected with a first positioning block and a second positioning block, the two first positioning blocks are used together to position the first metal insert on the carbon fiber preform, the two second positioning blocks are used together to position the second metal insert on the carbon fiber preform, a gas storage box is fixedly connected in the airbag, the gas storage box is sealed with a sealing cover, the gas storage box and the sealing cover are filled with high-pressure gas, the sealing cover is provided with a through hole, the through hole of the sealing cover is sealed and fixed with a blocking block, and the blocking block releases the blocking of the through hole of the sealing cover in a high temperature state.

[0005] As a preferred technical solution of the present invention, the density of the gas storage box and the sealing cover are both less than 2.7g / cm³.

[0006] As a preferred technical solution of the present invention, the blocking block is a truncated cone block, the through hole of the sealing cover is a truncated cone hole, and the diameters of the through holes of the blocking block and the sealing cover gradually decrease from the side close to the gas storage box to the side away from the gas storage box.

[0007] As a preferred technical solution of the present invention, the blocking block is made of a material that melts at 80°C-100°C.

[0008] As a preferred technical solution of the present invention, the sealing cover is fixedly connected with a blocking plate, and the blocking plate is in contact with the blocking block to prevent the blocking block from moving.

[0009] As a preferred technical solution of the present invention, the first positioning block and the second positioning block are made of the same material as the first metal insert and the second metal insert.

[0010] As a preferred technical solution of the present invention, the airbag is fixedly connected with a reserved rod, a release agent is coated on the outside of the reserved rod, and the reserved rod is used to release the high-pressure gas in the airbag.

[0011] As a preferred technical solution of the present invention, it also includes a first extrusion block, which is slidably connected in the fixed mold, and the movable mold is slidably connected to the second extrusion block, the airbag is provided with a protrusion, and the first extrusion block and the second extrusion block are used together to extrude the protrusion, the first extrusion block is slidably connected to the moving block, and the moving block is rotatably connected to a rotating rod, the rotating rod is threadedly connected to the fixed mold, the first extrusion block is provided with a positioning column, and the second extrusion block is provided with a groove, and the groove is used to limit the positioning column.

[0012] As a preferred technical solution of the present invention, the first extrusion block and the second extrusion block are both provided with a first inclined surface and a third inclined surface, the fixed mold and the movable mold are both provided with a second inclined surface and a fourth inclined surface, the second inclined surface is used to extrude the adjacent first inclined surface, the fourth inclined surface is used to extrude the adjacent third inclined surface, and the airbag is located between the second inclined surface and the fourth inclined surface.

[0013] A thermoplastic carbon fiber crank comprises a carbon fiber matrix, a first insert and a second insert are fixedly connected to the carbon fiber matrix, the three are formed by an integrated process, and the carbon fiber sheet on the carbon fiber matrix is ​​a laminated structure.

[0014] Compared with the prior art, the present invention has the following advantages: the present invention embeds the airbag into the carbon fiber preform so that the airbag, its internal air storage box and sealing cover jointly apply extrusion force to the interior of the carbon fiber preform without providing a reserved hole for inflating the airbag, and the crank preform and the first metal insert and the second metal insert thereon are formed integrally, thereby improving the structural integrity of the workpiece after the carbon fiber preform is formed.

[0015] The present invention seals the through hole on the sealing cover by using a sealing block and a blocking plate together, thereby reducing the possibility of sealing failure of the sealing cover and the gas storage box during the preparation process, and automatically releases the seal of the through hole of the sealing cover under high temperature by setting the material of the sealing block, thereby completing the automatic pressurization process.

[0016] The present invention extrude the protrusion by the first extrusion block and the second extrusion block, thereby actively increasing the air pressure in the airbag, and cooperates with the sealing cover and the air storage box to further increase the internal pressure of the carbon fiber preform, thereby improving the structural strength of the carbon fiber preform after integral molding.

[0017] The carbon fiber matrix, the first insert and the second insert of the present invention are formed in an integrated manner, so that the produced carbon fiber crank has better integrity and stability, and the overall impact resistance is stronger, which can bring a better riding experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of the three-dimensional structure of the invention; Figure 2 The three-dimensional structural diagram of the fixed mold and the movable mold of the invention; Figure 3 A cross-sectional view of the invented carbon fiber matrix; Figure 4 A cross-sectional view of the invented airbag; Figure 5 A cross-sectional view of the invented gas storage box; Figure 6 A cross-sectional view of the invented gas storage box and the sealing cover; Figure 7 It is a schematic diagram of the three-dimensional structure of the movable mold, the first extrusion block and the second extrusion block of the invention; Figure 8 A cross-sectional view of the first extrusion block and the second extrusion block of the invention; Fig. 9 For invention Figure 8 The enlarged view of point A in the middle; Fig.10 For invention Figure 8 The enlarged view of point B in the middle; Fig.11 It is a schematic diagram of the three-dimensional structure of the invented carbon fiber matrix and carbon fiber cloth.

[0019] Figure numerals: 1, fixed mold, 101, carbon fiber matrix, 102, first insert, 103, second insert, 104, carbon fiber cloth, 105, clamping part, 2, movable mold, 201, first positioning block, 202, second positioning block, 3, airbag, 301, protrusion, 302, reserved rod, 4, air storage box, 5, sealing cover, 6, blocking block, 7, blocking plate, 8, first extrusion block, 9, second extrusion block, 901, first inclined surface, 902, second inclined surface, 903, third inclined surface, 904, fourth inclined surface, 10, moving block, 11, rotating rod, 12, positioning column, 13, groove. DETAILED DESCRIPTION

[0020] First of all, it should be pointed out that in the different described embodiments, the same parts are provided with the same reference numerals or the same component names, wherein the disclosure contained in the entire description can be transferred to the same parts with the same reference numerals or the same component names. Selected positional descriptions in the description, such as top, bottom, lateral, etc., also refer to the directly described and shown figures and are transferred to the new positions in the case of a change in position.

[0021] A thermoplastic carbon fiber forming device, such as Figure 1-Figure 6 As shown, it includes a fixed mold 1, a movable mold 2 and an airbag 3. The fixed mold 1 and the movable mold 2 together form a female mold, and the two are used together to provide external extrusion pressure to the carbon fiber preform. The airbag 3 is used to act as a male mold to provide internal extrusion pressure to the carbon fiber preform. The fixed mold 1 and the movable mold 2 are both fixedly connected with a first positioning block 201 and a second positioning block 202. The two first positioning blocks 201 are used together to position the first metal insert on the carbon fiber preform, and the two second positioning blocks 202 are used together to position the second metal insert on the carbon fiber preform. An air storage box 4 is fixedly connected in the airbag 3. The air storage box 4 is sealed with a sealing cover 5. High-pressure gas is filled in the air storage box 4 and the sealing cover 5. The sealing cover 5 is provided with a through hole. The through hole of the sealing cover 5 is sealed and fixed with a blocking block 6. The blocking block 6 releases the blocking of the through hole of the sealing cover 5 in a high temperature state.

[0022] In the above scheme, the fixed mold 1 and the movable mold 2 are both made of aluminum alloy, and the two are connected by bolts, and cooperate with the airbag 3 to extrude the carbon fiber preform. The airbag 3 is not provided with an air pipe connected to the outside of the carbon fiber preform. The air storage box 4 and the sealing cover 5 are both made of materials with a density less than 2.7g / cm³ (such as aluminum, synthetic plastic or hard rubber material), so as to reduce the influence of the two on the weight of the carbon fiber crank. The air storage box 4 and the sealing cover 5 are firmly bonded to the inside of the airbag 3 (or fixed by friction pressing, etc.), and the outer side of the airbag 3 is not coated with a release agent. Therefore, when the carbon fiber crank is formed, the airbag 3 and the air storage box 4 and the sealing cover 5 are fixed inside the carbon fiber crank, which will not affect the mechanical properties of the carbon fiber crank. The gas storage box 4 and the sealing cover 5 can be filled with solid or liquid gas (such as non-toxic gas such as dry ice), or high-pressure gas can be directly input. In this solution, high-pressure gas is filled into the gas storage box 4 and the sealing cover 5 (dry ice can also be directly filled into the gas storage box 4 and the sealing cover 5, and high-pressure gas is automatically formed after dry ice sublimates), thereby increasing the air pressure in the airbag 3 when the sealing block 6 releases the seal of the through hole of the sealing cover 5, so that the airbag 3 provides sufficient internal pressure to the carbon fiber preform, thereby promoting the cross-linking reaction of the carbon fiber material.

[0023] As a preferred technical solution of the present invention, Figure 5 and Figure 6 As shown, the blocking block 6 is a truncated cone block, and the through hole of the sealing cover 5 is a truncated cone hole. The diameters of the through holes of the blocking block 6 and the sealing cover 5 gradually decrease from the side close to the gas storage box 4 to the side away from the gas storage box 4. The blocking block 6 is made of a material that melts at 80°C-100°C.

[0024] In the above scheme, the through holes on the blocking block 6 and the sealing cover 5 are both truncated cone-shaped, which improves the performance of the blocking block 6 in resisting the squeezing force of the high-pressure gas in the sealing cover 5 when it is not melted, thereby reducing the possibility of premature leakage of the high-pressure gas in the gas storage box 4 and the sealing cover 5. The blocking block 6 is made of a material with a melting point between 80°C and 100°C (such as Fischer-Tropsch wax), and then after the through holes on the sealing cover 5 are released from sealing, the blocking block 6 is washed away by the airflow when it melts, so that the connecting area of ​​the through holes of the sealing cover 5 is rapidly expanded, thereby improving the efficiency of the through holes on the sealing cover 5 in ejecting gas outward.

[0025] As a preferred technical solution of the present invention, Figure 4-Figure 6 As shown, the sealing cover 5 is fixedly connected with a blocking plate 7 , and the blocking plate 7 is in contact with the blocking block 6 to prevent the blocking block 6 from moving.

[0026] In the above solution, the blocking plate 7 contacts with the blocking block 6 to provide support force for the blocking block 6, thereby reducing the probability that the blocking block 6 is pushed by the high-pressure gas to move out of the sealing cover 5.

[0027] As a preferred technical solution of the present invention, Figure 1 and Figure 2 As shown, the first positioning block 201 and the second positioning block 202 are made of the same material as the first metal insert and the second metal insert.

[0028] As a preferred technical solution of the present invention, Figure 2 and Figure 3 As shown, the airbag 3 is fixedly connected with a reserved rod 302 , and a release agent is coated on the outside of the reserved rod 302 . The reserved rod 302 is used to release the high-pressure gas in the airbag 3 .

[0029] In the above scheme, the material of the first positioning block 201 and the second positioning block 202 is consistent with the material of the first metal insert and the second metal insert, so that the four always maintain the same thermal expansion ratio, ensuring that the position of the first metal insert and the second metal insert relative to the carbon fiber preform is not misaligned during the integral forming process. After the carbon fiber preform is integrally formed, the staff hammers the reserved rod 302 to puncture the airbag 3, release the high-pressure gas in the airbag 3, and then balance the internal and external pressure difference of the carbon fiber preform, and reduce the influence of the internal and external pressure difference stress on the carbon fiber preform. The diameter of the reserved rod 302 is less than 1mm, which is smaller than the diameter of the reserved hole on the carbon fiber crank in the existing technology for inflating the airbag 3 (10mm-20mm). Therefore, the degree of damage to the structural integrity of the carbon fiber preform by the reserved rod 302 in this scheme is less than the degree of damage to the structural integrity of the carbon fiber preform by the existing reserved hole.

[0030] The working principle of the above scheme is: when the staff prepares to use the present device to make a carbon fiber crank, they first prepare the fixed mold 1, the movable mold 2, the airbag 3, the first metal insert and the second metal insert, and the air storage box 4 and the sealing cover 5 in the airbag 3 are filled with high-pressure gas. The staff puts the airbag 3, the first metal insert and the second metal insert in position, and then the staff lays the carbon fiber sheets pre-impregnated with resin layer by layer on the outside of the airbag 3, and at the same time uses the carbon fiber sheets to fix the airbag 3, the first metal insert and the second metal insert together, thereby making a carbon fiber preform, and the reserved rod 302 passes through the carbon fiber preform and contacts with the outside.

[0031] After the carbon fiber preform is made, the staff puts the carbon fiber preform between the fixed mold 1 and the movable mold 2, so that the first metal insert is located between the two first positioning blocks 201, and the second metal insert is located between the two second positioning blocks 202, and the fixed mold 1 and the movable mold 2 are fixed with bolts. Then the staff puts the fixed mold 1 and the movable mold 2 into an oven, and heats the fixed mold 1 and the movable mold 2 and the carbon fiber preform inside the oven. The viscosity of the pre-impregnated resin in the carbon fiber gradually increases during the heating process. When the temperature rises to 100°C, the oven is switched to the insulation mode, and the carbon fiber and its The pre-impregnated resin gradually undergoes a cross-linking reaction at high temperature. At this time, the blocking block 6 melts under the influence of high temperature, and the blocking block 6 releases the seal on the through hole of the sealing cover 5. The high-pressure gas in the air storage box 4 and the sealing cover 5 is ejected outward through the through hole of the sealing cover 5. The high-pressure gas ejects the melted blocking block 6 together during the injection process, thereby accelerating the melting speed of the blocking block 6. After the high-pressure gas rushes into the airbag 3, the airbag 3 expands. The airbag 3 applies an extrusion force to the carbon fiber preform inside, thereby promoting a closer combination of the carbon fiber and the pre-impregnated resin inside, thereby making a carbon fiber crank with a higher density.

[0032] After keeping the fixed mold 1 and the movable mold 2 warm for several hours until the carbon fiber crank is formed, the staff closes the oven, takes out the fixed mold 1 and the movable mold 2, removes the bolts on the fixed mold 1 and the movable mold 2, opens the fixed mold 1 and the movable mold 2 and takes out the carbon fiber crank, and then the staff hammers the reserved rod 302 with a tool (such as a nail), and the reserved rod 302 moves into the carbon fiber crank and punctures the airbag 3, and the high-pressure gas in the airbag 3 overflows outward through the hole left by the reserved rod 302 to balance the internal and external pressures of the carbon fiber crank. When the gas in the airbag 3 no longer leaks outward, the staff fills the hole left by the reserved rod 302 with the existing carbon fiber patching material, and then the staff allows the carbon fiber crank to naturally cool to room temperature. The staff takes out the carbon fiber crank and cleans the fixed mold 1 and the movable mold 2.

[0033] Embodiment 2: Based on embodiment 1, Figure 1 , Figure 2 and Figure 7-Figure 11 As shown, as a preferred technical solution of the present invention, it also includes a first extrusion block 8, the first extrusion block 8 is slidably connected in the fixed mold 1, the movable mold 2 is slidably connected to the second extrusion block 9, the airbag 3 is provided with a protrusion 301, the first extrusion block 8 and the second extrusion block 9 are used together to extrude the protrusion 301, the first extrusion block 8 is slidably connected to the moving block 10, the moving block 10 is rotatably connected to the rotating rod 11, the rotating rod 11 is threadedly connected to the fixed mold 1, the first extrusion block 8 is provided with a positioning column 12, and the second extrusion block 9 is provided with a groove 13, and the groove 13 is used to limit the positioning column 12.

[0034] In the above scheme, if Fig.11As shown, the carbon fiber preform is wrapped with upper and lower layers of carbon fiber cloth 104 before being placed between the fixed mold 1 and the movable mold 2, thereby ensuring the integrity and continuity of the surface pattern of the carbon fiber crank after production is completed, and reducing the influence of wrinkles generated when winding the carbon fiber prepreg cloth on the appearance of the carbon fiber crank. The two layers of carbon fiber cloth 104 are both trimmed prepreg carbon fiber sheets. Through holes that do not hinder the movement of the positioning column 12 are reserved on the two carbon fiber cloths 104, so they will not be embedded between the positioning column 12 and the groove 13. The fixed mold 1 and the movable mold 2 are jointly provided with a clamping part 105. The shape of the clamping part 105 is similar to the inner contour of the fixed mold 1. The clamping part 105 is used to clamp the upper and lower layers of carbon fiber cloth 104, and then fix the two layers of carbon fiber cloth 104. The initial state of the first extrusion block 8 and the second extrusion block 9 is as shown in Figure 7 As shown, the positioning column 12 and the groove 13 are used to make the first extrusion block 8 move together with the second extrusion block 9. The first extrusion block 8 and the second extrusion block 9 are used to extrude the carbon fiber preform outside the raised portion 301, so that the carbon fiber preform and the raised portion 301 at this location shrink into the airbag 3 at the same time, thereby increasing the pressure of the airbag 3 on the inside of the carbon fiber preform.

[0035] As a preferred technical solution of the present invention, Figure 7 and Figure 9-11 As shown, the first extrusion block 8 and the second extrusion block 9 are both provided with a first inclined surface 901 and a third inclined surface 903, the fixed mold 1 and the movable mold 2 are both provided with a second inclined surface 902 and a fourth inclined surface 904, the second inclined surface 902 is used to extrude the adjacent first inclined surface 901, the fourth inclined surface 904 is used to extrude the adjacent third inclined surface 903, and the airbag 3 is located between the second inclined surface 902 and the fourth inclined surface 904.

[0036] In the above scheme, the second inclined surface 902 and the fourth inclined surface 904 on the fixed mold 1 correspond to the first inclined surface 901 and the third inclined surface 903 on the first extrusion block 8 respectively, and the second inclined surface 902 and the fourth inclined surface 904 on the movable mold 2 correspond to the first inclined surface 901 and the third inclined surface 903 on the second extrusion block 9 respectively. The second inclined surface 902 and the fourth inclined surface 904 respectively extrude the adjacent first inclined surface 901 and the adjacent third inclined surface 903, so that the first extrusion block 8 and the second extrusion block 9 are close to each other, thereby increasing the external extrusion force provided by the first extrusion block 8 and the second extrusion block 9 to the carbon fiber preform. The airbag 3 is located between the second inclined surface 902 and the fourth inclined surface 904, thereby ensuring that both sides of the airbag 3 are subjected to equal extrusion pressure, so that the pressure applied by the first extrusion block 8 and the second extrusion block 9 to the airbag 3 is more stable.

[0037] The working principle of the above scheme is as follows: when the staff puts the carbon fiber preform between the fixed mold 1 and the movable mold 2, the staff needs to lay two layers of carbon fiber cloth 104 between the fixed mold 1 and the movable mold 2, the two layers of carbon fiber cloth 104 are respectively located on the upper and lower sides of the carbon fiber preform, and ensure that the second extrusion block 9 is located on the right side of the adjacent movable mold 2, and then the movable mold 2 is installed on the upper side of the fixed mold 1, the positioning column 12 is inserted into the groove 13, the clamping part 105 clamps the two layers of carbon fiber cloth 104, the positioning column 12 is located in the through hole reserved for the two layers of carbon fiber cloth 104, and then the staff uses bolts to fix the fixed mold 1 and the movable mold 2, and the staff The operator manually rotates the rotating rod 11, and the rotating rod 11 moves along the thread into the fixed mold 1. The rotating rod 11 drives the moving block 10 and the first extrusion block 8 to move to the left together. The first extrusion block 8 drives the second extrusion block 9 to move to the left together through the positioning column 12 and the groove 13. At this time, because the first inclined surface 901 on the first extrusion block 8 and the second extrusion block 9 is not in contact with the adjacent second inclined surface 902, the first extrusion block 8 and the second extrusion block 9 do not clamp the adjacent carbon fiber cloth 104. The carbon fiber cloth 104 is fixed by the clamping part 105 and does not move with the friction between the first extrusion block 8 and the second extrusion block 9.

[0038] When the first extrusion block 8 and the second extrusion block 9 move to the left, they respectively squeeze the carbon fiber preform located at the protrusion 301 through the adjacent carbon fiber cloth 104, and squeeze the carbon fiber preform and the protrusion 301 to deform to the left, until the first inclined surfaces 901 on the first extrusion block 8 and the second extrusion block 9 are respectively in contact with the adjacent second inclined surfaces 902, and the two third inclined surfaces 903 are respectively in contact with the adjacent fourth inclined surfaces 904, the second inclined surface 902 guides the adjacent first inclined surface 901, and the fourth inclined surface 904 guides the adjacent third inclined surface 903. The first extrusion block 8 moves to the upper left under the guidance of the first inclined surface 901 and the third inclined surface 903 thereon, and the second extrusion block 9 moves to the lower left under the guidance of the first inclined surface 901 and the third inclined surface 903 thereon, until the first extrusion block 8 and the second extrusion block 9 jointly clamp the adjacent carbon fiber cloth 104, and the staff stops rotating the rotating rod 11. At this time, the protrusion 301 of the airbag 3 is squeezed and retracted to a state flush with its right side surface, and the air pressure in the airbag 3 is further increased, thereby increasing the compactness of the carbon fiber on the carbon fiber preform during the one-piece molding process.

[0039] After the staff takes the carbon fiber crank out of the fixed mold 1 and the movable mold 2, they remove the excess carbon fiber cloth 104 at the corners by grinding or the like.

[0040] Embodiment 3: Based on embodiment 2, Figure 1As shown, a thermoplastic carbon fiber crank includes a carbon fiber matrix 101, on which a first insert 102 and a second insert 103 are fixedly connected. The three are formed in an integrated manner, so that the produced carbon fiber crank has better integrity and stability, thereby making the upper limit of the overall bearing capacity of the carbon fiber crank higher. The carbon fiber sheet on the carbon fiber matrix 101 is a laminated structure, so that the fiber direction and angle are easy to control. Finally, it is manufactured by mold hot pressing and integrated molding, so that the overall impact resistance of the carbon fiber crank is stronger.

[0041] Taking into account the weight of cranks currently on the market, the weight of metal cranks is roughly between 200 and 300g, while the weight of the carbon fiber cranks in this solution is between 100 and 200g. By replacing materials, the weight is reduced by about 30%, making the carbon fiber cranks in this solution more advantageous in the pursuit of excellent lightweight design. In addition, the shock absorption ability of metal cranks is not as good as that of carbon fiber cranks. Therefore, during riding, the carbon fiber cranks are subject to less bumpy impact, which can bring a better riding experience.

[0042] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A thermoplastic carbon fiber forming device, characterized in that: The invention comprises a fixed mold (1), a movable mold (2) and an air bag (3), wherein the fixed mold (1) and the movable mold (2) together form a female mold, and the two are used together to provide an external extrusion force to a carbon fiber preform, and the air bag (3) is used to act as a male mold to provide an internal extrusion force to the carbon fiber preform, and the fixed mold (1) and the movable mold (2) are both fixedly connected to a first positioning block (201) and a second positioning block (202), and the two first positioning blocks (201) are used together to position a first metal insert on the carbon fiber preform. The second positioning blocks (202) are used together to position the second metal insert on the carbon fiber preform. The airbag (3) is fixedly connected with an air storage box (4). The air storage box (4) is sealed with a sealing cover (5). The air storage box (4) and the sealing cover (5) are filled with high-pressure gas. The sealing cover (5) is provided with a through hole. The through hole of the sealing cover (5) is sealed and fixedly connected with a blocking block (6). The blocking block (6) releases the blocking of the through hole of the sealing cover (5) in a high-temperature state.

2. A thermoplastic carbon fiber forming device according to claim 1, characterized in that: The density of the gas storage box (4) and the sealing cover (5) are both less than 2.7 g / cm³.

3. A thermoplastic carbon fiber forming device according to claim 2, characterized in that: The blocking block (6) is a truncated cone block, the through hole of the sealing cover (5) is a truncated cone hole, and the diameters of the through holes of the blocking block (6) and the sealing cover (5) gradually decrease from a side close to the gas storage box (4) to a side away from the gas storage box (4).

4. A thermoplastic carbon fiber forming device according to claim 3, characterized in that: The blocking block (6) is made of a material that melts at 80°C-100°C.

5. A thermoplastic carbon fiber forming device according to claim 4, characterized in that: The sealing cover (5) is fixedly connected with a blocking plate (7), and the blocking plate (7) is in contact with the blocking block (6) and is used to prevent the blocking block (6) from moving.

6. The thermoplastic carbon fiber forming device according to claim 1, characterized in that: The first positioning block (201) and the second positioning block (202) are made of the same material as the first metal insert and the second metal insert.

7. The thermoplastic carbon fiber forming device according to claim 1, characterized in that: The airbag (3) is fixedly connected to a reserved rod (302), the outside of the reserved rod (302) is coated with a release agent, and the reserved rod (302) is used to release the high-pressure gas in the airbag (3).

8. The thermoplastic carbon fiber forming device according to claim 7, characterized in that: The invention also comprises a first extrusion block (8), wherein the first extrusion block (8) is slidably connected to the fixed mold (1), the movable mold (2) is slidably connected to a second extrusion block (9), the airbag (3) is provided with a protrusion (301), the first extrusion block (8) and the second extrusion block (9) are used together to extrude the protrusion (301), the first extrusion block (8) is slidably connected to a moving block (10), the moving block (10) is rotatably connected to a rotating rod (11), the rotating rod (11) is threadedly connected to the fixed mold (1), the first extrusion block (8) is provided with a positioning column (12), the second extrusion block (9) is provided with a groove (13), the groove (13) is used to limit the positioning column (12).

9. A thermoplastic carbon fiber forming device according to claim 8, characterized in that: The first extrusion block (8) and the second extrusion block (9) are both provided with a first inclined surface (901) and a third inclined surface (903); the fixed mold (1) and the movable mold (2) are both provided with a second inclined surface (902) and a fourth inclined surface (904); the second inclined surface (902) is used to extrude the adjacent first inclined surface (901); the fourth inclined surface (904) is used to extrude the adjacent third inclined surface (903); and the airbag (3) is located between the second inclined surface (902) and the fourth inclined surface (904).

10. A thermoplastic carbon fiber crank, comprising a carbon fiber matrix (101), a first insert (102) and a second insert (103) being fixedly connected to the carbon fiber matrix (101), the three being formed in one piece, and the carbon fiber sheets on the carbon fiber matrix (101) being a laminated structure.

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