High-strength bicycle chain wheel and crank integrated connection structure

Abstract

The utility model relates to the technical field of bicycle, and disclose a kind of high-strength bicycle sprocket and crank integrated connection structure, including sprocket, crank, sprocket is hollow disc and fixed bearing at center, it is also equipped with folding integrated assembly, symmetrical rotating structure and auxiliary fixing assembly, folding integrated assembly is linked with symmetrical rotating structure, can make crank flexible folding around sprocket, auxiliary fixing assembly can lock crank folding position;The utility model structure integrated design avoids split type structure gap and welding structure stress defect, improves connection strength and power transmission stability, folding function substantially reduces storage and transportation space, substantially shortens bicycle installation time, meets modern bicycle diversification use demand, applicable to various bicycle transmission system optimization.

Description

Technical Field

[0001] This utility model relates to the field of bicycle technology, specifically to a high-strength integrated connection structure between a bicycle chain wheel and a crank. Background Technology

[0002] In a bicycle drivetrain, the sprocket and crank are the core components for power transmission: the sprocket transmits power to the rear wheel by meshing with the chain, while the crank serves as the input carrier for the rider's pedaling force. The stability of their connection directly determines the bicycle's power transmission efficiency and riding safety. With the diversification of bicycle applications, from daily commuting to long-distance riding, users have placed higher demands on the strength, durability, and space adaptability of the drivetrain. The components need to remain structurally stable under long-term high-load pedaling to avoid power loss due to loose connections, and they also need to minimize space occupation during storage and transportation. Therefore, designing a high-strength sprocket and crank connection structure with flexible adjustment characteristics has become the key to meeting the needs of modern bicycle use.

[0003] Traditional bicycle sprockets and cranks often use separate bolt-fixed or simple welded structures, which have significant drawbacks: Separate bolt-fixed structures are prone to loosening due to vibration after prolonged use, causing not only abnormal noise but also relative displacement between the sprocket and crank, reducing power transmission efficiency, and in severe cases, even posing a risk of component detachment; while welded structures can ensure initial connection strength, they cannot be quickly folded or disassembled, require significant space for bicycle storage, and are prone to cracking due to stress concentration at the weld joints, requiring complete component replacement for later maintenance, increasing usage costs and failing to meet diverse user needs. Therefore, we propose a high-strength integrated connection structure for bicycle sprockets and cranks. Utility Model Content

[0004] To address the shortcomings of existing technologies, this invention provides a high-strength integrated connection structure between the bicycle sprocket and crank, thus solving the aforementioned problems.

[0005] To achieve the above-mentioned objectives, this utility model provides the following technical solution: A high-strength bicycle sprocket and crank integrated connection structure, comprising a sprocket and a crank, wherein the sprocket is in the shape of a hollow disc, and a bearing is fixedly installed at the center of the sprocket, and a crank is provided on the side of the sprocket bearing away from the disc; A folding integrated assembly is disposed inside the sprocket bearing. The folding integrated assembly includes a flipping structure, a rotating structure, and a sliding structure. The bearing end of the sprocket away from the disc has a U-shaped groove. The flipping structure is disposed inside the groove sidewall of the sprocket. The rotating structure is disposed inside the flipping structure. The sliding structure is disposed inside the flipping structure and connected to the rotating structure. A symmetrical rotating structure arranged inside the crank, wherein the symmetrical rotating structure is arranged inside the crank and connected with the rotating structure; An auxiliary fixing assembly arranged on the side surface of the sprocket bearing end, wherein the auxiliary fixing assembly includes a set screw and a screw hole, a through hole in a penetrating form is opened on the side surface of the bearing end of the sprocket, the set screw is threadedly mounted in the through hole of the bearing end of the sprocket, a penetrating screw hole is opened on the side surface of the crank, and the screw hole is in threaded fit connection with the set screw, for assisting in fixing the folding position of the crank.

[0006] Preferably, the flipping structure includes a rotating shaft, a limiting block and a rotating groove, a cylindrical rotating shaft is fixedly mounted on the inner side wall of the groove of the sprocket, a fan-shaped limiting block is fixedly mounted on the side surface of the rotating shaft, a penetrating rotating groove is opened on the side surface of the crank, the rotating groove is in the shape of a cylinder with an L-shaped cross section, the rotating groove is in rotating fit connection with the rotating shaft, and the side wall of the transverse end of the rotating groove is in snap-fit engagement with the limiting block.

[0007] Preferably, the rotating structure includes sliding chutes and rotating shafts, a Chinese character "zhong"-shaped sliding chute is opened on each of the two opposite side surfaces of the limiting block and the rotating groove, the two sets of sliding chutes are distributed in axisymmetry, a cylindrical rotating shaft is fixedly mounted on the inner side wall of the vertical end of each sliding chute, and the two sets of rotating shafts are distributed in axisymmetry.

[0008] Preferably, the rotating structure further includes connecting rods, rotating holes and upright posts, the connecting rods are C-shaped square sheets, the two sets of connecting rods are distributed at equal intervals in the longitudinal direction, a penetrating rotating hole is opened on the side surface of the end point of each connecting rod, the two sets of rotating holes are distributed at equal intervals in the vertical direction, the rotating hole at the top of the connecting rod is in rotating fit connection with the rotating shaft inside the limiting block, and a cylindrical upright post is fixedly mounted on the side surface of the bent part of the connecting rod.

[0009] Preferably, the symmetrical rotating structure includes symmetrical connecting rods and symmetrical rotating holes, the symmetrical connecting rods are C-shaped square sheets rotated 180 degrees around the Z axis, the two sets of symmetrical connecting rods are distributed at equal intervals in the longitudinal direction, a penetrating symmetrical rotating hole is opened on the side surface of each symmetrical connecting rod, the symmetrical rotating hole at the top of the symmetrical connecting rod is in rotating fit connection with the rotating shaft inside the rotating groove, the symmetrical rotating hole in the middle of the symmetrical connecting rod is in rotating fit connection with the upright post, and the two sets of connecting rods and the two sets of symmetrical connecting rods are distributed in an ABAB-type staggered and longitudinally equidistant manner.

[0010] Preferably, the sliding structure includes sliding blocks and rotating posts, the sliding blocks are cuboids distributed in series, the two sets of sliding blocks are distributed in axisymmetry, a cylindrical rotating post is fixedly mounted between each two cuboids of the sliding block, the sliding block is in sliding fit connection with the side wall of the transverse end of the sliding chute, the rotating post is in rotating fit connection with the rotating hole at the bottom of the connecting rod, and the other set of rotating posts is in rotating fit connection with the symmetrical rotating hole at the bottom of the symmetrical connecting rod.

[0011] Compared with the prior art, the advantages of this utility model are: A high-strength integrated connection structure for bicycle sprocket and crank is provided, which has the following advantages: 1. This high-strength bicycle sprocket and crank integrated connection structure, through an integrated design, links the sprocket and crank via a shaft, groove, connecting rod, and symmetrical connecting rods. Combined with the auxiliary fixation of set screws and screw holes, it avoids the gap problems of split structures and the stress defects of welded structures. During riding, power is directly and stably transmitted to the sprocket through the crank without relative displacement loss. Furthermore, the components work together to withstand long-term high-load pedaling, significantly reducing the risk of loosening, detachment, or cracking, and significantly improving the durability of the transmission system and riding safety. The folding integrated component allows for flexible crank folding: manually rotating the crank engages the shaft and groove, which in turn drive the connecting rod and symmetrical connecting rods. The slider slides along the groove to assist folding. After folding, it is positioned by a locking block and fixed with set screws. This significantly shortens bicycle installation time, reduces storage and transportation space requirements, and balances practicality and flexibility to meet the diverse usage needs of modern users. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is an exploded view of the present invention; Figure 3 This is a schematic diagram of the cross-section of this utility model; Figure 4 This is a cross-sectional view of the present invention; Figure 5 for Figure 4 A magnified view of part A in the diagram.

[0013] In the diagram: 1. Sprocket; 2. Crank; 3. Set screw; 4. Screw hole; 5. Shaft; 6. Limiting block; 7. Rotating block; 8. Slide groove; 9. Rotating shaft; 10. Connecting rod; 11. Column; 12. Rotating hole; 13. Connecting rod two; 14. Rotating hole two; 15. Sliding block; 16. Rotating column. Detailed Implementation

[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0015] Please see Figure 1-5A high-strength bicycle sprocket and crank integrated connection structure includes a sprocket 1 and a crank 2. The sprocket 1 is in the shape of a hollow disc, and a bearing is fixedly installed at the center of the sprocket 1. The crank 2 is provided on the side of the sprocket 1 opposite to the disc. A folding integrated assembly is set inside the bearing of sprocket 1. The folding integrated assembly includes a flipping structure, a rotating structure and a sliding structure. A U-shaped groove is opened at the bearing end of sprocket 1 away from the disc. The flipping structure is set inside the side wall of the groove of sprocket 1. The rotating structure is set inside the flipping structure. The sliding structure is set inside the flipping structure and connected to the rotating structure. A symmetrical rotating structure is set inside the crank 2, and the symmetrical rotating structure is set inside the crank 2 and connected to the rotating structure. An auxiliary fixing component is provided on the side of the bearing end of the sprocket 1. The auxiliary fixing component includes a set screw 3 and a screw hole 4. A through hole is opened on the side of the bearing end of the sprocket 1, and the set screw 3 is threadedly installed in the through hole of the bearing end of the sprocket 1. A through screw hole 4 is opened on the side of the crank 2, and the screw hole 4 is threadedly connected to the set screw 3 to assist in fixing the folded position of the crank 2.

[0016] Furthermore, the flipping structure includes a rotating shaft 5, a limiting block 6, and a rotating groove 7. A cylindrical rotating shaft 5 is fixedly installed on the inner side wall of the groove of the sprocket 1, and a fan-shaped limiting block 6 is fixedly installed on the side of the rotating shaft 5. A through-type rotating groove 7 is opened on the side of the crank 2, and the rotating groove 7 is a cylindrical L-shaped cross-section. The rotating groove 7 is rotatably connected to the rotating shaft 5, and the horizontal end side wall of the rotating groove 7 is engaged with the limiting block 6. The rotating shaft 5 is fixedly installed on the side wall of the groove of the sprocket 1, providing a stable axis for the crank 2 to fold around the sprocket 1, ensuring that the crank 2 always rotates around a fixed trajectory during folding, avoiding structural jamming or damage caused by deviation. The limiting block 6, in addition to being connected to the rotating groove 7... In addition to the interlocking of the horizontal end sidewall, the crank 2 can also limit its rotation angle through its own fan-shaped arc. When the crank 2 is folded to the designated position, the interlocking of the limiting block 6 and the sidewall of the rotating groove 7 can directly block the crank 2 from continuing to rotate, preventing excessive folding from damaging the component connection relationship. At the same time, it provides a positioning reference for the end point of the crank 2's unfolding / folding. The rotating groove 7 realizes the crank 2's rotation action through the rotational cooperation with the rotating shaft 5. On the other hand, its L-shaped horizontal end can accommodate the limiting block 6, ensuring that the limiting block 6 rotates synchronously with the rotating shaft 5. Furthermore, through the interlocking of the horizontal end sidewall with the limiting block 6, a mechanical lock is formed after the crank 2 is folded into place, enhancing the structural stability in the folded state.

[0017] Further, the rotating structure comprises sliding grooves 8 and rotating shafts 9, two opposite side surfaces of the limiting block 6 and the rotating groove 7 are each provided with a sliding groove 8 shaped like a Chinese character "zhong", the two sets of sliding grooves 8 are distributed in axial symmetry, the inner side wall of the vertical end of each sliding groove 8 is fixedly provided with a cylindrical rotating shaft 9, and the two sets of rotating shafts 9 are distributed in axial symmetry. The vertical end of the "zhong"-shaped sliding groove 8 is used for fixing the rotating shaft 9, and provides a rotation pivot for the connecting rod 10 and the symmetric connecting rod 13; the transverse end provides a sliding space for the sliding block 15 of the sliding structure. Meanwhile, the symmetric distribution characteristic of the "zhong" shape makes the two sets of rotating shafts 9, connecting rods 10 and symmetric connecting rods 13 bear balanced force, avoiding structural deformation caused by excessive force on one side. The rotating shaft 9 serves as the connection hub between the connecting rod 10 and the limiting block 6, and between the symmetric connecting rod 13 and the rotating groove 7, and its surface smoothness can reduce the frictional resistance during the rotation process, so that the crank 2 can be folded / unfolded smoothly. At the same time, the cooperation of the rotating shaft 9 with the rotating hole 11 and the symmetric rotating hole 14 can reduce the gap between components and improve the overall rigidity of the structure.

[0018] Further, the rotating structure further comprises a connecting rod 10, rotating holes 11 and a stand column 12. The connecting rod 10 is in a C-shaped square sheet shape, and the two sets of connecting rods 10 are distributed at equal intervals in the longitudinal direction. The side surface of the end of the connecting rod 10 is each provided with a through-type rotating hole 11, and the two sets of rotating holes 11 are distributed at equal intervals in the vertical direction. The rotating hole 11 at the top of the connecting rod 10 is in rotating fit connection with the rotating shaft 9 inside the limiting block 6, and the side surface of the turning part of the connecting rod 10 is fixedly provided with a cylindrical stand column 12. The C-shaped square sheet-shaped connecting rod 10 is connected with the rotating shaft 9 of the limiting block 6 through the top rotating hole 11, the bottom rotating hole 11 is connected with the rotating column 16 of the sliding structure, and the stand column 12 at the turning part is connected with the symmetric rotating hole 14 in the middle of the symmetric connecting rod 13, so as to convert the turning-over motion of the crank 2 into the linear motion of the sliding structure. The through-type hole body of the rotating hole 11 is matched with the sizes of the rotating shaft 9 and the rotating column 16, so that the connecting rod 10 does not shake when rotating around the rotating shaft 9 and the rotating column 16. Meanwhile, the smooth treatment of the hole wall can reduce the rotation wear and prolong the service life of the component. The vertical equidistant distribution of the two sets of rotating holes 11 keeps the force bearing points at both ends of the connecting rod 10 balanced, avoiding unilateral stress concentration. The cylindrical structure of the stand column 12 fixed at the turning part of the connecting rod 10 serves as the connection intermediary between the connecting rod 10 and the symmetric connecting rod 13, and its axis is kept coaxial with the axes of the rotating hole 11 and the symmetric rotating hole 14, so that the symmetric connecting rod 13 is stable when rotating around the stand column 12. At the same time, the length of the stand column 12 is adapted to the distance between the two sets of connecting rods 10, so as to prevent the symmetric connecting rod 13 from interfering with other components during the rotation process.

[0019] Furthermore, the symmetrical rotation structure includes symmetrical connecting rods 13 and symmetrical rotating holes 14. The symmetrical connecting rods 13 are C-shaped squares that rotate 180 degrees around the Z-axis, and the two sets of symmetrical connecting rods 13 are longitudinally equidistant. A through-hole symmetrical rotating hole 14 is opened on the side of the symmetrical connecting rod 13, and the symmetrical rotating hole 14 at the top of the symmetrical connecting rod 13 is rotatably connected to the rotating shaft 9 inside the rotating groove 7. The symmetrical rotating hole 14 in the middle of the symmetrical connecting rod 13 is rotatably connected to the column 12. The two sets of connecting rods 10 and the two sets of symmetrical connecting rods 13 are longitudinally equidistant in an ABAB-type staggered arrangement. The C-shaped square of the symmetrical connecting rod 13, rotating 180 degrees around the Z-axis, forms a mirror symmetrical structure with the connecting rod 10, and its top symmetrical rotating hole 14... 4 is connected to the rotating shaft 9 in the rotating groove 7. The symmetrical rotating hole 14 in the middle is connected to the column 12, and the symmetrical rotating hole 14 at the bottom is connected to the rotating column 16. When the crank 2 is flipped, the symmetrical connecting rod 13 rotates synchronously with the connecting rod 10. The offset of the unilateral force is offset by the mirror motion, so that the crank 2 always folds along the preset trajectory, avoiding folding jamming caused by deformation of the unilateral components. The symmetrical rotating hole 14 is a through hole and is adapted to the size of the rotating shaft 9, column 12, and rotating column 16. Its distribution position is symmetrical with the rotating hole 11 of the connecting rod 10, so that the rotation angle of the symmetrical connecting rod 13 is consistent with that of the connecting rod 10, improving the overall rigidity of the symmetrical rotating structure and avoiding structural loosening caused by increased gaps after long-term use.

[0020] Furthermore, the sliding structure includes sliders 15 and rotating columns 16. The sliders 15 are cuboids arranged in series, and the two sets of sliders 15 are axially symmetrical. A cylindrical rotating column 16 is fixedly installed between each of the two sets of cuboids of sliders 15. The sliders 15 are slidably connected to the transverse sidewall of the slide groove 8. The rotating column 16 is rotatably connected to the rotating hole 11 at the bottom of the connecting rod 10, and the other set of rotating columns 16 is rotatably connected to the symmetrical rotating hole 14 at the bottom of the symmetrical connecting rod 13. The series of cuboids of sliders 15 slidably engage with the transverse sidewall of the slide groove 8. This cuboid structure prevents the sliders 15 from rotating or shifting within the slide groove 8, ensuring that the sliding direction always extends along the transverse end of the slide groove 8. The axially symmetrical distribution of the two sets of sliders 15 allows for the synchronous transmission of power between the two sets of connecting rods 10 and the symmetrical connecting rod 13. The force exerted by the rotating column 16 ensures that the crank 2 is evenly stressed on both sides when folding, preventing the structure from tilting due to excessively fast sliding on one side. The rotating column 16 is a cylindrical structure fixed between the two sets of cuboids of the slider 15, and it rotates and engages with the rotating hole 11 at the bottom of the connecting rod 10 and the symmetrical rotating hole 14 at the bottom of the symmetrical connecting rod 13. Its function is to convert the rotational motion of the connecting rod 10 into the linear sliding of the slider 15. When the connecting rod 10 rotates around the rotating axis 9, it pushes the slider 15 to slide along the transverse end of the slide groove 8 through the rotating column 16. At the same time, the smooth surface of the rotating column 16 can reduce the friction with the rotating hole 11 and the symmetrical rotating hole 14, ensuring the smoothness of the sliding action. The two sets of rotating columns 16 correspond to the connecting rod 10 and the symmetrical connecting rod 13 respectively. The synchronous sliding of the two sets of linkage structures further improves the coordination of the folding action.

[0021] Structure description: Sprocket 1: It is in the shape of a hollow disc, with a bearing fixed at the center, which is used for fitting and installation with the bottom bracket mounting hole. Its hollow design reduces weight while ensuring strength, and the bearing mounting position provides a connection foundation for crank 2 and other structures; Crank 2: It is connected to sprocket 1 through a specific structure, and is internally provided with a symmetrical rotating structure, which interlocks with other structures during folding, and transmits pedaling force to the sprocket during daily riding to drive the chain to rotate; Set screw 3: It is threadedly mounted in the through hole at the bearing end of sprocket 1, and is used to cooperate with the screw hole 4 on the side of crank 2 after crank 2 is folded in place, so as to fasten the folding position of crank 2 and prevent loosening during riding; Screw hole 4: Screw hole 4 is opened on the side of crank 2, which is a structure matched with set screw 3. After the two are threadedly connected, the stability of the folding position of crank 2 is guaranteed, so that the folded state can be maintained; Rotating shaft 5: Rotating shaft 5 is fixed on the side wall of the groove of sprocket 1, which is the core fulcrum for the folding rotation of crank 2, providing a stable rotation axis for crank 2, so that its folding and unfolding actions are carried out along a fixed track; Limiting block 6: Limiting block 6 is fan-shaped, fixed on the side of rotating shaft 5, and is in snap fit with the side wall of the transverse end of rotating groove 7, so as to limit the turning angle of crank 2; Rotating groove 7: Rotating groove 7 is located on the side of crank 2, in the shape of a cylinder with L-shaped cross section, which is rotatably matched with rotating shaft 5 to realize the turning of crank 2. Its L-shaped transverse end accommodates limiting block 6, forming a locking effect when folded in place; Sliding groove 8: Sliding groove 8 is in the shape of a Chinese character "zhong", distributed on the opposite sides of limiting block 6 and rotating groove 7. The vertical end fixes rotating shaft 9, and the transverse end provides a sliding space for sliding block 15, ensuring the stability of structural movement; Rotating shaft 9: Rotating shaft 9 is cylindrical, fixed on the inner side wall of the vertical end of sliding groove 8, serving as the rotation fulcrum of connecting rod 10 and symmetrical connecting rod 13 to reduce rotation friction; Connecting rod 10: Connecting rod 10 is a C-shaped square piece, connected to rotating shaft 9 through the top rotating hole 11, the bottom is matched with rotating column 16, and the upright post 12 at the turning part is connected with symmetrical connecting rod 13 to transmit folding motion; Upright post 12: Upright post 12 is fixed at the turning part of connecting rod 10, which is the connection intermediary between connecting rod 10 and symmetrical connecting rod 13, ensuring that the two keep coaxial when rotating and avoid interference; Rotating hole 11: Rotating hole 11 penetrates through the end point of connecting rod 10, matches with rotating shaft 9 and rotating column 16, ensuring that connecting rod 10 rotates stably without shaking; Second connecting rod 13: The second connecting rod 13 is the symmetrical connecting rod 13, which is mirror-symmetrical to connecting rod 10, and is connected with rotating shaft 9, upright post 12 and rotating column 16 through symmetrical rotating hole 14 to offset the unilateral force; Rotating Hole 2 14: Rotating Hole 2 14 is also known as symmetrical rotating hole 14, which is distributed on the side of symmetrical connecting rod 13 and is adapted to the size of related components so that its rotation angle is consistent with that of connecting rod 10. Slider 15: Slider 15 is a series of cuboids that slide in conjunction with the horizontal end of the slide groove 8. It is symmetrically distributed on both sides and synchronously transmits the force of the connecting rod 10 and the symmetrical connecting rod 13. Rotating column 16: The rotating column 16 is fixed between the two sets of cuboids of the slider 15, and rotates in conjunction with the bottom hole of the connecting rod 10 and the symmetrical connecting rod 13 to realize the conversion between rotation and sliding.

[0022] Working principle: First, the bearing of sprocket 1 and crank 2 are horizontally aligned. After being fixed in place by passing horizontally through the bottom bracket mounting hole of the bicycle, crank 2 is folded. The crank 2 is manually rotated around the pivot 5 within the groove 7 to begin folding. As crank 2 rotates, connecting rod 10 in the rotating structure rotates around the pivot 9 within the limiting block 6. Simultaneously, symmetrical connecting rod 13 in the symmetrical rotating structure also rotates around the pivot 9 within the groove 7. The rotation of connecting rod 10 and symmetrical connecting rod 13 causes slider 15 in the sliding structure to slide on the horizontal sidewall of the groove 8. The rotating post 16 on slider 15 engages with the rotating hole 11 at the bottom of connecting rod 10 and the symmetrical rotating hole 14 at the bottom of symmetrical connecting rod 13, allowing the rotation of connecting rod 10 and symmetrical connecting rod 13 to be smoothly converted into the rotation of slider 1. During the sliding of crank 2, the column 12 at the bend of connecting rod 10 and the symmetrical rotating hole 14 in the middle of the symmetrical connecting rod 13 rotate and cooperate to further transmit the motion, ensuring that the rotating structure and the symmetrical rotating structure rotate in coordination when crank 2 is folded. When crank 2 is folded to the designated position, the limiting block 6 engages with the horizontal side wall of the rotating groove 7 to restrict crank 2 from continuing to rotate. At this time, tighten the set screw 3 so that it engages with the screw hole 4 on the side of crank 2 to assist in fixing the folded position of crank 2, achieving the effect of facilitating bicycle storage and transportation and reducing space occupation. At the same time, the cooperation of each structure also makes the folding and unfolding process smooth and the structure stable. When using, unfolding crank 2 and fixing it can enhance the integrated connection strength between the sprocket and crank when the bicycle is riding normally, and transmit riding power.

[0023] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-strength bicycle sprocket and crank integrated connection structure, characterized in that, comprising: a sprocket (1) and a crank (2), wherein the sprocket (1) is in the shape of a hollow disc, a bearing is fixedly mounted at the center of the sprocket (1), and the crank (2) is arranged on the side surface of the end of the bearing of the sprocket (1) facing away from the disc; an integrated folding assembly arranged inside the bearing of the sprocket (1), wherein the integrated folding assembly comprises a turnover structure, a rotation structure and a sliding structure, a concave-shaped groove is formed at the end of the bearing of the sprocket (1) facing away from the disc, the turnover structure is arranged on the inner side wall of the groove of the sprocket (1), the rotation structure is arranged inside the turnover structure, and the sliding structure is arranged in the turnover structure and connected with the rotation structure; a symmetric rotation structure arranged inside the crank (2), wherein the symmetric rotation structure is arranged inside the crank (2) and connected with the rotation structure; an auxiliary fixing assembly arranged on the side surface of the bearing end of the sprocket (1), wherein the auxiliary fixing assembly comprises a set screw (3) and a screw hole (4), a through-type through hole is formed on the side surface of the bearing end of the sprocket (1), the set screw (3) is threadedly mounted in the through hole at the bearing end of the sprocket (1), a through-type screw hole (4) is formed on the side surface of the crank (2), and the screw hole (4) is in threaded fit connection with the set screw (3) for assisting in fixing the folding position of the crank (2).

2. The high-strength integrated connection structure for a bicycle sprocket and crank according to claim 1, wherein the turnover structure comprises a rotating shaft (5), a limit block (6) and a rotating groove (7), a cylindrical rotating shaft (5) is fixedly mounted on the inner side wall of the groove of the sprocket (1), a fan-shaped limit block (6) is fixedly mounted on the side surface of the rotating shaft (5), a through-type rotating groove (7) is formed on the side surface of the crank (2), the rotating groove (7) is in a cylindrical shape with an L-shaped cross section, the rotating groove (7) is in rotating fit connection with the rotating shaft (5), and the side wall of the transverse end of the rotating groove (7) is in clamping fit with the limit block (6).

3. The high-strength bicycle sprocket and crank integrated connection structure according to claim 2, characterized in that, The rotation structure comprises sliding grooves (8) and rotating shafts (9), wherein opposite side surfaces of the limit block (6) and the rotating groove (7) are both provided with a Chinese character "zhong" shaped sliding groove (8), the two sets of sliding grooves (8) are distributed in axis symmetry, a cylindrical rotating shaft (9) is fixedly mounted on the inner side wall of the vertical end of each sliding groove (8), and the two sets of rotating shafts (9) are distributed in axis symmetry.

4. The high-strength bicycle sprocket and crank integrated connection structure according to claim 3, characterized in that, The rotation structure further comprises connecting rods (10), rotating holes (11) and columns (12), wherein the connecting rods (10) are in the shape of C-shaped square sheets, the two sets of connecting rods (10) are distributed at equal intervals in the longitudinal direction, a through-type rotating hole (11) is formed on the side surface of the end point of each connecting rod (10), the two sets of rotating holes (11) are distributed at equal intervals in the vertical direction, the rotating hole (11) at the top of the connecting rod (10) is in rotating fit connection with the rotating shaft (9) inside the limit block (6), and a cylindrical column (12) is fixedly mounted on the side surface of the turning part of the connecting rod (10).

5. The high-strength bicycle sprocket and crank integrated connection structure according to claim 4, characterized in that, The symmetrical rotation structure includes symmetrical connecting rods (13) and symmetrical rotating holes (14). The symmetrical connecting rods (13) are C-shaped square pieces that rotate 180 degrees around the Z-axis. The two sets of symmetrical connecting rods (13) are longitudinally equidistant. The symmetrical rotating holes (14) are opened on the side of the symmetrical connecting rods (13). The symmetrical rotating holes (14) at the top of the symmetrical connecting rods (13) are rotatably connected to the rotating shaft (9) inside the rotating groove (7). The symmetrical rotating holes (14) in the middle of the symmetrical connecting rods (13) are rotatably connected to the column (12). The two sets of connecting rods (10) and the two sets of symmetrical connecting rods (13) are longitudinally equidistant in an ABAB staggered manner.

6. The high-strength bicycle sprocket and crank integrated connection structure according to claim 5, characterized in that, The sliding structure includes a slider (15) and a rotating column (16). The sliders (15) are cuboids arranged in series, and the two sets of sliders (15) are axially symmetrical. A cylindrical rotating column (16) is fixedly installed between the two sets of cuboids of the sliders (15). The sliders (15) are slidably connected to the side wall of the slide groove (8). The rotating column (16) is rotatably connected to the rotating hole (11) at the bottom of the connecting rod (10). The other set of rotating columns (16) is rotatably connected to the symmetrical rotating hole (14) at the bottom of the symmetrical connecting rod (13).

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