Chain wheel structure and power-assisted bicycle

Abstract

The utility model relates to the technical field of power-assisted bicycle, disclose a chain wheel structure and power-assisted bicycle, it includes frame main body, first wheel disc, second wheel disc, chain and chain cover, the chain cover is provided with mounting portion and blocking portion, the mounting portion fixed connection is established in the riser portion lower extreme with first wheel disc adjacent arrangement, the blocking portion covers the entering angle department of chain entering first wheel disc is set up, the utility model discloses the entering angle department of chain entering first wheel disc is covered to the blocking portion of chain cover, effectively blocks the contact risk of clothes and moving part, combines the structural optimization design and gives consideration to security and light weight demand simultaneously, effectively prevents clothes to be rolled into the meshing area of chain and sprocket, avoids the transmission system to be stuck and personal injury accident, promotes the riding security.

Description

Technical Field

[0001] This utility model belongs to the field of power-assisted bicycle technology, specifically relating to a sprocket structure and a power-assisted bicycle. Background Technology

[0002] In the field of electric bicycles, with the increasing demand for cycling and the widespread adoption of electric motor assistance, vehicle performance has been continuously enhanced, and cycling speeds have also increased significantly. However, this has been accompanied by increasingly prominent safety issues. One common and quite dangerous situation is that when cyclists are riding normally, especially at high speeds, loose trouser legs, skirts, or other clothing can easily get caught in the rapidly rotating chain and sprocket meshing area. Once this happens, it can not only cause the bicycle to suddenly jam, resulting in a fall and injury for the rider, but also pose a serious threat to personal safety due to the clothing being too tightly entangled.

[0003] To address this issue, the industry generally adopts a fully enclosed metal chain guard as a protective solution. While this type of chain guard effectively isolates clothing from the chain during movement, it also has significant drawbacks. The metal material and fully enclosed structure make the chain guard quite heavy, which contradicts the current design trend of lightweight and energy-efficient electric bicycles, especially lightweight electric bicycles powered by lithium batteries. The heavy chain guard increases the overall burden of the bicycle, negatively impacting both range and handling agility. Therefore, how to ensure riding safety, effectively prevent clothing from getting caught, and simultaneously achieve lightweight design has become a pressing technical challenge in this field, and existing technologies have not yet provided a satisfactory solution. Utility Model Content

[0004] To address the shortcomings of the prior art, this utility model provides a sprocket structure and a power-assisted bicycle, which solves the problem of how to ensure riding safety, effectively prevent clothing from getting caught, and also take into account the lightweight design of the product.

[0005] The technical effects to be achieved by this utility model are realized through the following aspects: In a first aspect, this utility model provides a sprocket structure, characterized in that it includes a frame body, a first sprocket, a second sprocket, a chain, and a chain guard; the frame body is provided with a seat tube and a rear fork; the first sprocket is rotatably disposed at the lower end of the seat tube; the second sprocket is rotatably disposed at the end of the rear fork; and the chain is sleeved between the first sprocket and the second sprocket. The chain cover is provided with an installation part and a blocking part. The installation part is fixedly connected to the lower end of the riser and is disposed adjacent to the first wheel. The blocking part is disposed at the entry angle of the chain into the first wheel.

[0006] In some implementations, the chain cover further includes a connecting part, and the mounting part and the blocking part are respectively connected to both sides of the connecting part; when the chain cover is installed on the riser, the mounting part is fixedly installed with the riser, the connecting part is located above the first wheel, and the blocking part is located outside the first wheel.

[0007] In some implementations, the riser section is provided with at least one threaded groove; the mounting section is provided with a movable groove that matches the threaded groove, and the movable groove and the threaded groove are locked in sequence by bolts to make the chain cover adjustablely connected to the riser section.

[0008] In some implementations, the mounting section is further provided with at least one first hollowed-out groove to reduce the mass of the chain cover.

[0009] In some implementations, the chain forms an entry angle when it engages with the first wheel; the blocking part is provided on the outside of the entry angle; the blocking part is also provided with a second hollow groove, and the second hollow groove has an arcuate surface that matches the first wheel.

[0010] In some implementations, a first rotating shaft is provided at the lower end of the riser section, and the other end of the first rotating shaft is connected to a foot pedal via a crank. The first wheel is fixedly sleeved on the first rotating shaft. An assist motor is provided in the rear fork section, and a second wheel is disposed on the assist motor. The first wheel and the second wheel are driven to rotate by the foot pedal and / or the assist motor.

[0011] In some implementations, both the first and second wheel disks have receiving grooves on their outer periphery, and when the chain is engaged with the first wheel disk, the chain is disposed in the receiving groove.

[0012] In some implementations, the chain is provided with a plurality of first engaging protrusions evenly arranged, and a first engaging groove is formed between adjacent first engaging protrusions; the receiving groove is provided with a second engaging protrusion that engages and matches the first engaging groove, and a second engaging groove that engages and matches the first engaging protrusion is formed between adjacent second engaging protrusions.

[0013] In some implementations, at least one through groove communicating with the outside is provided at the bottom of the second meshing groove to reduce meshing friction.

[0014] Secondly, this utility model provides a power-assisted bicycle, including the aforementioned sprocket structure.

[0015] In summary, this utility model has at least the following advantages: The utility model provides a sprocket structure and a power-assisted bicycle, including a frame body, a first sprocket, a second sprocket, a chain, and a chain guard. The chain guard is provided with a mounting part and a blocking part. The mounting part is fixedly connected to the lower end of the riser and is adjacent to the first sprocket. The blocking part covers the angle at which the chain enters the first sprocket. This utility model, by covering the angle at which the chain enters the first sprocket with the blocking part of the chain guard, effectively prevents the risk of contact between clothing and moving parts. Simultaneously, combined with optimized structural design that balances safety and lightweight requirements, it effectively prevents clothing from getting caught in the chain and sprocket meshing area, avoiding transmission system jamming and personal injury accidents, thus improving riding safety. Attached Figure Description

[0016] Figure 1 This is a perspective view of the electric bicycle according to an embodiment of the present utility model; Figure 2 This is a first schematic diagram of the first wheel and chain according to an embodiment of the present utility model; Figure 3 This is a second schematic diagram of the first wheel and chain according to an embodiment of the present utility model; Figure 4 This is a first schematic diagram of the chain cover according to an embodiment of the present utility model; Figure 5 This is a first schematic diagram of the chain cover according to an embodiment of the present utility model.

[0017] Marked in the image: 10. Frame body; 11. Stem tube; 12. Rear fork; 13. First pivot; 14. Crank; 15. Pedals; 16. Assist motor; 17. Rear wheel; 20. First wheel; 21. Receiving groove; 22. Second engagement protrusion; 23. Second engagement groove; 24. Guide groove; 30. Second roulette wheel; 40. Chain; 41. First meshing protrusion; 42. First meshing groove; 50. Chain cover; 51. Mounting part; 52. Blocking part; 53. Connecting part; 54. First hollow groove; 55. Movable groove; 56. Second hollow groove; 60. Bolts; a. Enter the included angle. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are some, but not all, of the embodiments of this utility model.

[0019] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0020] Example 1: Please see the appendix Figure 1-5 This utility model provides a first embodiment of a sprocket structure, including a frame body 10, a first sprocket 20, a second sprocket 30, a chain 40, and a chain guard 50; the frame body 10 is provided with a seat tube 11 and a rear fork 12; the first sprocket 20 is rotatably disposed at the lower end of the seat tube 11; the second sprocket 30 is rotatably disposed at the end of the rear fork 12; the chain 40 is sleeved between the first sprocket 20 and the second sprocket 30; the chain guard 50 is provided with a mounting part 51 and a blocking part 52, the mounting part 51 is fixedly connected to the lower end of the seat tube 11 and is disposed adjacent to the first sprocket 20, and the blocking part 52 is disposed covering the entry angle α of the chain 40 entering the first sprocket 20.

[0021] In this embodiment of the invention, the present invention aims to solve the safety hazard of preventing loose clothing from being caught in the chain 40 during high-speed riding of an electric bicycle, while reducing the weight of the protective device to conform to the trend of lightweight design. The entry angle where the chain 40 enters the first sprocket 20 refers to the area where the chain 40 and the first sprocket 20 begin to engage. This angle is determined by the relative position of the chain 40's trajectory and the tangent of the sprocket. Specifically, this entry angle can be determined by setting reference marks on the chain 40 and measuring the coordinates of the initial contact point, for example, by using a laser rangefinder to record the intersection position of the chain 40 pitch and the sprocket tooth tip. Furthermore, the blocking part 52, which covers this entry angle, can adopt a non-fully enclosed fixing structure. For example, the blocking part 52 can be directly glued to the lower surface of the riser 11 with adhesive, or the blocking part 52 can be bound to the area adjacent to the riser 11 and the first sprocket 20 using an elastic band, thereby ensuring that the blocking part 52 accurately covers the critical area where clothing is easily caught. This invention provides targeted protection for high-risk areas by setting a blocking part 52 only at the entry angle where the chain 40 enters the first wheel 20, avoiding material redundancy in the fully enclosed chain cover 50, thereby reducing the overall weight of the chain cover 50 while preventing the risk of clothing from getting caught.

[0022] The sprocket structure includes a frame body 10, a first sprocket 20, a second sprocket 30, a chain 40, and a chain guard 50. The frame body 10 has a seat tube 11 and a rear fork 12, providing stable support for the overall structure and ensuring the precise and reliable mounting positions of the first sprocket 20 and the second sprocket 30. The first sprocket 20 is rotatably mounted at the lower end of the seat tube 11, serving as the drive wheel; the second sprocket 30 is rotatably mounted at the end of the rear fork 12, serving as the driven wheel; the chain 40 is fitted between the first sprocket 20 and the second sprocket 30, forming a power transmission path. During the rotational engagement of the chain 40 and the first sprocket 20, an entry angle is formed, and this area becomes a high-risk point where clothing can easily be caught due to the high-speed movement of the chain 40. The chain guard 50 is provided with a mounting part 51 and a blocking part 52. The mounting part 51 is fixedly connected to the lower end of the riser 11 and is adjacent to the first wheel 20. The blocking part 52 is provided at the entrance angle, thereby providing local protection for this critical area and effectively preventing loose trouser legs or skirts from contacting the chain 40, avoiding vehicle jamming or personal safety risks caused by clothing getting caught.

[0023] Furthermore, as a specific embodiment, the chain guard 50 can be made of polycarbonate material. The mounting part 51 is fixed to the lower end of the riser 11 by welding. The profile of the blocking part 52 is designed to match the geometry of the entry angle, ensuring stable coverage of the target area during riding. Thus, this design only provides targeted protection for the high-risk area where the chain 40 enters the first sprocket 20, avoiding a fully enclosed structure and significantly reducing the amount of material used.

[0024] Therefore, this technical solution reliably prevents clothing from being caught in the chain 40 during high-speed riding, while reducing the weight of the chain guard 50, which helps to achieve a lightweight design for the bicycle, improves the overall range and handling flexibility, and effectively balances the technical requirements of safety protection and lightweighting. Example 2: Based on Embodiment 1, this utility model provides a second embodiment of the sprocket structure to further illustrate the chain cover 50 in Embodiment 1.

[0025] In some embodiments, the chain cover 50 further includes a connecting part 53, and the mounting part 51 and the blocking part 52 are respectively connected to both sides of the connecting part 53; when the chain cover 50 is installed on the riser part 11, the mounting part 51 is fixedly installed on the riser part 11, the connecting part 53 is located above the first wheel 20, and the blocking part 52 is located outside the first wheel 20.

[0026] In this embodiment, the connecting part 53 refers to the intermediate transition structure in the chain cover 50 used to connect the mounting part 51 and the blocking part 52. It can be implemented using a bent metal sheet or a plastic bracket. Its purpose is to provide an independent connection point, allowing the blocking part 52 to be spatially adjusted relative to the mounting part 51. The mounting part 51 and the blocking part 52 are respectively connected to both sides of the connecting part 53, meaning that the mounting part 51 and the blocking part 52 form a non-rigid connection relationship through the connecting part 53. This can be implemented using a hinged structure or a sliding snap-fit ​​method. Its purpose is to separate the fixing function of the mounting part 51 from the protective function of the blocking part 52, avoiding coverage deviation caused by direct connection. The mounting part 51 is fixedly installed with the riser part 11. 51 is mechanically connected to the riser 11 to form a stable connection, which can be achieved by a snap-fit ​​structure or riveting. The purpose is to ensure that the chain cover 50 maintains its installation position during vehicle vibration. The connecting part 53 is located above the first wheel 20, meaning that the spatial positioning of the connecting part 53 is in the top area of ​​the first wheel 20. It can be designed as an arc-shaped support structure that adapts to the contour of the wheel, with the purpose of retaining only the necessary support coverage area and reducing material redundancy. The blocking part 52 is located outside the first wheel 20, meaning that the blocking part 52 extends to the outer peripheral protection area of ​​the first wheel 20. It can be achieved by a mesh-like or perforated plate structure, with the purpose of accurately intercepting the risk of clothing getting caught in the angle where the chain 40 enters.

[0027] Specifically, the present invention uses the connecting part 53 as a transition bridge between the mounting part 51 and the blocking part 52, so that after the mounting part 51 is fixed in the riser part 11, the blocking part 52 can independently adjust its spatial orientation to ensure precise coverage of the angle area where the chain 40 enters the first wheel 20. At the same time, the layout of the connecting part 53 above the first wheel 20 provides only minimal support, avoiding material waste in the fully enclosed structure and significantly reducing the overall weight of the chain cover 50. The positioning of the blocking part 52 on the outside of the first wheel 20 directly protects the high-risk area of ​​the chain 40 engagement entrance, effectively isolating the risk of clothing getting caught in the chain and avoiding the weight burden caused by excessive wrapping, thereby achieving structural lightweighting while ensuring safety performance.

[0028] As a preferred embodiment, the specific implementation of this utility model is as follows: the connecting part 53 of the chain cover 50 can be a U-shaped bent aluminum alloy bracket, the mounting part 51 is provided with multiple mounting holes for fixed connection with the riser part 11 through a snap-fit ​​structure, the blocking part 52 is an arc-shaped plastic plate that matches the outer periphery of the first wheel 20. When the chain cover 50 is installed, the connecting part 53 spans across the top of the first wheel 20 to provide lightweight support, and the blocking part 52 extends to the outside of the area where the chain 40 enters to form precise protection.

[0029] Through the above solution, this utility model realizes flexible adjustment of the installation position of the chain cover 50, ensuring that the blocking part 52 accurately covers the angle area where the chain 40 enters to effectively prevent the risk of clothing getting caught; at the same time, by optimizing the structural layout of the connecting part 53 and the blocking part 52, the amount of material used is reduced, the weight of the chain cover 50 is reduced, which meets the lightweight design requirements of electric bicycles and improves riding safety and vehicle energy efficiency. In some embodiments, an improved sprocket structure includes: the riser section 11 is provided with at least one threaded groove; the mounting section 51 is provided with a movable groove 55 that matches the threaded groove, and the movable groove 55 and the threaded groove are locked in sequence by bolts 60 so that the chain cover 50 is adjustablely connected to the riser section 11.

[0030] In this embodiment, the screw groove refers to the slot structure provided on the riser 11 for fixing the bolt 60. It can be implemented by using a circular, elliptical, or elongated slot, and its purpose is to provide a stable installation reference point. The movable slot 55 refers to the slot provided on the mounting part 51 that mates with the screw groove. It can be implemented by using a straight, arc, or L-shaped slot, and its purpose is to allow the chain cover 50 to be finely adjusted laterally or longitudinally during installation. The adjustable connection mechanism refers to the connection method in which the bolt 60 slides in the movable slot 55 to achieve position adjustment and then lock. It can be implemented by using a single-point or multi-point adjustable mechanism, and its purpose is to ensure that the blocking part 52 can be accurately aligned with the chain 40 entering the included angle area.

[0031] Specifically, the present invention uses the screw groove on the riser 11 as a fixed reference point. The movable groove 55 on the mounting part 51 matches the screw groove to form a slidable connection. When the bolt 60 is loosened, the chain cover 50 can move along the movable groove 55 to adjust its position. After the position is adjusted, the bolt 60 is tightened to make the chain cover 50 firmly fixed, thereby ensuring that the blocking part 52 accurately covers the angle where the chain 40 enters, effectively preventing the risk of clothing getting caught, while taking into account both the ease of installation and the reliability of the structure.

[0032] As a specific implementation method, the present invention is implemented as follows: A long strip-shaped threaded groove is provided on the riser 11, and a straight movable groove 55 is provided on the mounting part 51. The bolt 60 is a standard hexagonal bolt 60. When installing the chain cover 50, the bolt 60 is first screwed into the threaded groove but not locked. The chain cover 50 is moved so that the blocking part 52 is aligned with the chain 40 and enters the included angle. Then the bolt 60 is fully locked to achieve position fixation.

[0033] With the above solution, the connection position between the chain cover 50 and the riser 11 can be finely adjusted according to the actual assembly situation, ensuring that the blocking part 52 accurately covers the angle where the chain 40 enters, effectively preventing clothing from being caught in the area of ​​the chain 40, improving the reliability of protection, and avoiding safety hazards caused by positional deviation. In some embodiments, the mounting part 51 is also provided with at least one first hollowed-out groove 54 to reduce the mass of the chain cover 50.

[0034] In this embodiment, the first hollow groove 54 refers to the opening area formed on the mounting part 51, which can be realized by different geometric shapes such as circles, ellipses or polygons, so as to effectively reduce the amount of material used while ensuring structural strength. Its purpose is to significantly reduce the overall mass of the chain cover 50 by partially removing material, while maintaining the strength required for the fixed connection between the mounting part 51 and the riser part 11.

[0035] Specifically, the present invention reduces unnecessary materials by excavating a first hollow groove 54 in the mounting part 51, thereby directly reducing the mass of the chain cover 50; at the same time, the hollow groove optimizes the material distribution, so that the mounting part 51 is evenly stressed during the fixing process, avoiding the risk of stress concentration caused by single-point structural weakening, and ensuring the stability of the chain cover 50 installation.

[0036] As a preferred embodiment, the present invention is implemented as follows: multiple circular hollow grooves are evenly distributed on the mounting part 51, and the edges of these hollow grooves are chamfered to reduce stress concentration; the mounting part 51 is made of lightweight alloy material, which further reduces the weight.

[0037] Through the above solution, this utility model effectively reduces the weight of the chain guard 50, lightens the overall load of the bicycle, and thus improves the range and maneuverability of the electric bicycle. In some embodiments, the chain 40 forms an entry angle when it rotates and engages with the first wheel 20; the blocking part 52 is provided on the outside of the entry angle; the blocking part 52 is also provided with a second hollow groove 56, and the second hollow groove 56 has an arcuate surface that matches the first wheel 20.

[0038] In this embodiment, the entry angle refers to a specific angular area formed during the engagement of the chain 40 and the first wheel 20. It can be determined using geometric analysis based on the tension of the chain 40 and the tooth profile of the wheel, with the aim of accurately locating high-risk areas where clothing is easily caught. The blocking part 52 covering the outside of the entry angle means that the blocking part 52 is configured to directly cover the outer area of ​​the entry angle. It can be installed in an adjustable manner to achieve fine-tuning of its position, with the aim of preventing clothing from entering the engagement point of the chain 40 and the wheel from this specific angle. Specifically, the second hollow groove 56 refers to the opening structure provided on the blocking part 52. It can be formed on the blocking part 52 using stamping or injection molding processes, and the second hollow groove 56 has an arc-shaped surface that matches the first wheel 20. Its purpose is to reduce the amount of material used to reduce the overall weight of the chain cover 50. At the same time, the arc-shaped surface ensures that the blocking part 52 does not occupy additional space or interfere with the normal rotation of the chain 40 when covering the critical area.

[0039] Specifically, the present invention identifies the entry angle formed when the chain 40 engages with the first wheel 20 as the key area where clothing gets caught. The blocking part 52 is precisely covered outside the entry angle to provide targeted physical isolation. At the same time, a second hollow groove 56 with a matching arc surface is provided on the blocking part 52. The amount of material used is reduced while maintaining the protective function, thereby optimizing both lightweight and safety protection.

[0040] As a preferred embodiment, the present invention is implemented as follows: the blocking part 52 can be injection molded from polycarbonate material, and its second hollow groove 56 is designed as an arc-shaped opening that conforms to the outer periphery of the first wheel 20. The radius of curvature of the arc-shaped opening is approximately matched with the radius of the first wheel 20, thereby providing effective protection and reducing weight when covering the included angle area.

[0041] Through the above solution, this utility model can effectively prevent clothing from being caught in the chain 40 at a specific angle when it enters the first wheel 20, while significantly reducing the overall weight of the chain cover 50, thus meeting the requirements of lightweight design for electric bicycles. Example 3: Based on Embodiment 1, this utility model provides a third embodiment of the sprocket structure to further illustrate the frame body 10, the first wheel 20, the second wheel 30, and the chain 40 in Embodiment 1.

[0042] In some embodiments, the lower end of the riser section 11 is provided with a first rotating shaft 13, the other end of the first rotating shaft 13 is connected to the foot pedal 15 through a crank 14, and the first wheel 20 is fixedly sleeved on the first rotating shaft 13; the rear fork section 12 is provided with a power assist motor 16, and the second wheel 30 is provided on the power assist motor 16; the first wheel 20 and the second wheel 30 are driven to rotate by the foot pedal 15 and / or the power assist motor 16.

[0043] In this embodiment, the riser 11 refers to the tubular structure in the frame body 10 used to support the steering of the front wheels. It can be made of aluminum alloy or carbon fiber composite material to balance structural strength and lightweight requirements. The first pivot 13 refers to the core rotating shaft that transmits human power input to the transmission system. It can be designed as a solid or hollow structure. Specifically, it can be fixedly connected to the first wheel 20 through heat fitting or keyway cooperation. The crank 14 refers to the lever mechanism that converts the torque of the pedal 15 into rotational motion. It can be made of forged aluminum alloy and surface hardened to ensure the reliability of torque transmission. The power assist motor 16 refers to the electric motor unit that provides auxiliary power. It can be a brushless DC motor or a permanent magnet synchronous motor to achieve efficient energy conversion and stable output.

[0044] Specifically, the present invention directly sets the first pivot 13 at the lower end of the riser 11, using the inherent structure of the frame as a support base, avoiding the introduction of additional supports, and anchoring the core drive component to the frame body 10, significantly improving system rigidity; the first pivot 13 forms a gapless rigid coupling with the pedal 15 through the crank 14, ensuring a linear transmission path for human input, reducing energy loss and the risk of instantaneous slippage; the rear fork 12 directly integrates the power assist motor 16, enabling direct coupling between the motor output shaft and the second wheel 30, eliminating redundant components such as intermediate gears or belts, and optimizing the energy transmission link; the dual-mode drive mechanism dynamically switches or works in coordination according to riding needs, maintaining the continuity of chain tension 40, especially suppressing abnormal chain swaying in high-speed power assist mode, reducing the possibility of clothing contacting dangerous areas.

[0045] As a specific implementation method, the present invention is implemented as follows: the power assist motor 16 is a brushless DC motor, the stator of which is fixed to the end of the rear fork 12, and the rotor directly drives the second wheel 30; the first rotating shaft 13 is made of alloy steel and is fixedly connected to the first wheel 20 through an interference fit; the crank 14 is made of high-strength aluminum alloy forging and the surface is treated with a wear-resistant coating to enhance its service life.

[0046] Through the above solution, this utility model effectively suppresses vibration and chain 40 jumping during high-speed rotation, reducing the potential risk of clothing being caught in the chain 40 area; at the same time, it eliminates the transition parts required for external installation, reduces local weight and optimizes spatial layout, meets the lightweight design goal, and improves the overall vehicle energy efficiency and handling flexibility. In some embodiments, both the first wheel 20 and the second wheel 30 are provided with receiving grooves 21 on their outer periphery. When the chain 40 is engaged with the first wheel 20, the chain 40 is disposed in the receiving groove 21.

[0047] In this embodiment, the receiving groove 21 refers to a recessed structure formed on the outer periphery of the wheel disc to accommodate the chain 40. It can be implemented using different cross-sectional shapes such as annular grooves, V-shaped grooves, or trapezoidal grooves. Its purpose is to restrict the lateral movement of the chain 40 during engagement, thereby reducing safety hazards caused by chain 40 misalignment. Simultaneously, it prevents the chain 40 from engaging with the first wheel disc 20 or the second wheel disc 30, ensuring its height does not exceed the sidewall of the receiving groove 21; that is, when the chain 40 engages with the first wheel disc 20 or the second wheel disc 30, gaps are unlikely to form, preventing the chain from clamping clothing again; further improving the anti-pinch effect.

[0048] Specifically, the present invention provides a receiving groove 21 on the outer periphery of the first wheel 20 and the second wheel 30, so that the chain 40 is precisely constrained in the groove when it meshes with the wheel. The groove wall provides lateral support, effectively preventing the chain 40 from sliding laterally due to vibration or load changes during high-speed rotation, ensuring that the chain 40 maintains a fixed position on the transmission path and avoiding unexpected gaps between it and the wheel.

[0049] As a specific embodiment, the solution of this utility model is implemented as follows: the receiving groove 21 can be designed with a U-shaped cross section. During the meshing process, part of the chain link or the entire material bar of the chain 40 is embedded in the receiving groove 21, thereby being stably restricted on the predetermined track.

[0050] Through the above solution, this utility model effectively reduces the risk of lateral displacement of the chain 40 during high-speed engagement, significantly reduces the possibility of rider's clothing being caught in the engagement area, and improves riding safety. In some embodiments, the chain 40 is provided with a plurality of first engagement protrusions 41 evenly arranged, and a first engagement groove 42 is formed between adjacent first engagement protrusions 41; the receiving groove 21 is provided with a second engagement protrusion 22 that engages and matches the first engagement groove 42, and a second engagement groove 23 that engages and matches the first engagement protrusion 41 is formed between adjacent second engagement protrusions 22.

[0051] In this embodiment, the first meshing protrusion 41 refers to the protrusion structure evenly distributed on the chain 40, which can be realized by metal stamping or injection molding, with the purpose of providing a stable meshing contact point to distribute dynamic loads; the first meshing groove 42 refers to the groove structure formed between adjacent first meshing protrusions 41, which can be designed with a U-shaped or V-shaped cross section, with the purpose of providing a precise embedding path for the second meshing protrusion 22 of the wheel; the second meshing protrusion 22 refers to the protrusion portion provided inside the receiving groove 21, which can be realized by a surface-hardened metal tooth structure, with the purpose of forming a tight fit with the first meshing groove 42 to resist centrifugal force; the second meshing groove 23 refers to the groove structure formed between adjacent second meshing protrusions 22, which can have an arc-shaped profile, with the purpose of interlocking with the first meshing protrusion 41 to enhance the overall meshing stability.

[0052] Specifically, the present invention achieves a smooth transition when the chain 40 enters the meshing area through the interlocking cooperation between the first meshing protrusion 41 of the chain 40 and the second meshing groove 23 of the wheel, as well as the geometric matching between the first meshing groove 42 and the second meshing protrusion 22, thereby reducing vibration caused by impact. At the same time, during high-speed rotation, the meshing structure evenly distributes the driving force to multiple contact points, effectively resisting the tendency of the chain 40 to disengage due to centrifugal force, thus maintaining a stable meshing relationship between the chain 40 and the wheel under dynamic load, and avoiding chain skipping or chain derailment.

[0053] As a preferred embodiment, the present invention is implemented as follows: the chain 40 is made of high-strength alloy steel or wear-resistant rubber belt, and its first meshing protrusion 41 is designed with a trapezoidal cross section to improve wear resistance; the receiving groove 21 of the first wheel 20 is provided with a toothed second meshing protrusion 22 that has been treated by high frequency quenching. The contour of the second meshing protrusion 22 is precisely matched with the first meshing groove 42 to ensure that the chain 40 and the wheel 22 maintain a continuous and stable meshing state during high-speed riding, and the chain 40 is evenly distributed with force during cyclic rotation.

[0054] The above solution effectively solves the problem of unstable chain engagement during high-speed riding, avoids chain skipping, chain slippage, or abnormal wear, and significantly improves the operational reliability and riding safety of the sprocket structure under dynamic loads. In some embodiments, at least one through groove 24 communicating with the outside is provided at the bottom of the second engagement groove 23 to reduce engagement friction.

[0055] In this embodiment, the guide groove 24 refers to the channel structure provided at the bottom of the second meshing groove 23 that communicates with the external environment. It can be implemented by means of a circular hole, a slit or a mesh structure. The purpose is to specifically alleviate the frictional resistance of the meshing area and avoid heat accumulation and contaminant retention caused by the closed structure.

[0056] Specifically, the present invention addresses this issue by placing the guide groove 24 at the bottom of the second meshing groove 23. This location is the area with the greatest contact pressure and the most concentrated friction when the chain 40 meshes with the wheel, effectively dispersing the meshing stress. At the same time, the guide groove 24 connects with the outside to form a flow path, allowing external lubricating oil to continuously flow into the meshing interface and internal wear debris to be discharged in a timely manner, thereby reducing the friction coefficient and preventing local overheating. The provision of at least one guide groove 24 ensures the redundancy of the flow path. Even if some channels fail due to debris blockage, the remaining channels can still maintain the flow of lubricating medium and the discharge of debris, ensuring the continuous and stable friction reduction effect.

[0057] As a preferred embodiment, the present invention is implemented as follows: the guide groove 24 can be implemented as a plurality of circular through holes evenly distributed at the bottom of the second meshing groove 23. These through holes are connected to the external environment, allowing the lubricating medium to flow freely during the meshing process of the chain 40 and the wheel. At the same time, a wheel made of metal is used to ensure structural strength.

[0058] Through the above solution, this utility model reduces the local overheating caused by meshing friction, effectively reduces the wear of chain 40 and wheel disc, and improves the operating efficiency and service life of the transmission system. Example 4: Based on Embodiment 1, Embodiment 2, or Embodiment 3, this utility model also discloses an electric bicycle, including a sprocket structure. The sprocket structure includes a frame body 10, a first sprocket 20, a second sprocket 30, a chain 40, and a chain guard 50. The frame body 10 is provided with a seat tube 11 and a rear fork 12. The first sprocket 20 is rotatably disposed at the lower end of the seat tube 11; the second sprocket 30 is rotatably disposed at the end of the rear fork 12; the chain 40 is sleeved between the first sprocket 20 and the second sprocket 30 to form a transmission path; the chain guard 50 is provided with a mounting part 51, a blocking part 52, and a connecting part 53. The mounting part 51 is fixedly connected to the lower end of the seat tube 11 and is adjacent to the first sprocket 20. The blocking part 52 covers the entry angle of the chain 40 into the first sprocket 20. The connecting part 53 positions the mounting part 51 and the blocking part 52 on opposite sides of the mounting part 51. After installation, the connecting part 53 is positioned above the first sprocket 20, while the blocking part 52 is located on the outside.

[0059] This invention provides partial protection by setting a blocking part 52 only at the entry angle where the chain 40 enters the first wheel 20, and by setting a first hollow groove 54 in the mounting part 51 of the chain cover 50 and a second hollow groove 56 in the blocking part 52 to reduce material usage. This effectively prevents loose trouser legs or skirts from getting caught while significantly reducing the weight of the protective device, achieving a synergistic optimization of safety protection and lightweight design. Specifically, the riser section 11 is provided with a screw groove, and the mounting part 51 is provided with a movable groove 55. The screw groove and the movable groove 55 are connected by bolts 60 for adjustable connection, facilitating fine-tuning of the chain cover 50 position according to actual assembly needs, ensuring that the blocking part 52 is always aligned with the chain 40 engagement point. The arc-shaped surface of the blocking part 52 matches the contour of the first wheel 20, providing a close-fitting protection to prevent clothing intrusion. The first wheel 20 is fixedly sleeved on the first rotating shaft 13 of the riser section 11. The crank 14 connects to the pedal 15, and the rear fork 12 is equipped with an assist motor 16 to drive the second wheel 30. The outer periphery of the first wheel 20 and the second wheel 30 is provided with a receiving groove 21 to accommodate the chain 40. The chain 40 is evenly distributed with first engagement protrusions 41 and first engagement grooves 42. The receiving groove 21 is provided with matching second engagement protrusions 22 and second engagement grooves 23 to improve transmission smoothness. The bottom of the second engagement groove 23 is provided with a guide groove 24 to connect to the outside, guide heat dissipation and reduce engagement resistance.

[0060] Through the above technical solution, this utility model specifically covers high-risk areas where clothing is easily caught, avoids the redundant design of a fully enclosed metal chain cover 50, optimizes material distribution while maintaining structural strength, effectively eliminates blind spots caused by chain 40 jumping or assembly errors, and significantly reduces the weight of the chain cover 50, ultimately achieving a balance between safety protection and lightweighting, and meeting the design requirements of power-assisted bicycles for high energy efficiency and maneuverability.

[0061] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0062] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0063] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0064] In this invention, unless otherwise expressly specified and limited, "above or below" the first feature may include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on" the first feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the first feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0065] Although the description of this utility model has been given in conjunction with the specific embodiments described above, it is obvious to those skilled in the art that many substitutions, modifications, and variations can be made based on the above description. Therefore, all such substitutions, modifications, and variations are included within the spirit and scope of the appended claims.

Claims

1. A sprocket structure, characterized in that, The bicycle includes a frame body (10), a first disc (20), a second disc (30), a chain (40), and a chain guard (50); the frame body (10) is provided with a seat tube (11) and a rear fork (12); the first disc (20) is rotatably disposed at the lower end of the seat tube (11); the second disc (30) is rotatably disposed at the end of the rear fork (12); the chain (40) is sleeved between the first disc (20) and the second disc (30); The chain cover (50) is provided with an installation part (51) and a blocking part (52). The installation part (51) is fixedly connected to the lower end of the riser part (11) and is arranged adjacent to the first wheel (20). The blocking part (52) is arranged to cover the entry angle of the chain (40) into the first wheel (20).

2. The sprocket structure according to claim 1, characterized in that, The chain cover (50) also includes a connecting part (53), and the mounting part (51) and the blocking part (52) are respectively connected to both sides of the connecting part (53); when the chain cover (50) is installed on the riser part (11), the mounting part (51) is fixedly set with the riser part (11), the connecting part (53) is located above the first wheel (20), and the blocking part (52) is located outside the first wheel (20).

3. The sprocket structure according to claim 2, characterized in that, The riser section (11) is provided with at least one threaded groove; the mounting section (51) is provided with a movable groove (55) that matches the threaded groove, and the movable groove (55) and the threaded groove are locked in sequence by bolts (60) so that the chain cover (50) is adjustablely connected to the riser section (11).

4. The sprocket structure according to claim 2, characterized in that, The mounting section (51) is also provided with at least one first hollowed-out groove (54) to reduce the mass of the chain cover (50).

5. A sprocket structure according to claim 2, characterized in that, The chain (40) forms an entry angle when it rotates and engages with the first wheel (20); the blocking part (52) is provided on the outside of the entry angle; the blocking part (52) is also provided with a second hollow groove (56), and the second hollow groove (56) has an arc-shaped surface that matches the first wheel (20).

6. A sprocket structure according to claim 1, characterized in that, The lower end of the riser (11) is provided with a first rotating shaft (13), and the other end of the first rotating shaft (13) is connected to the pedal (15) through a crank (14). The first wheel (20) is fixedly sleeved on the first rotating shaft (13). The rear fork (12) is provided with a power assist motor (16), and the second wheel (30) is provided on the power assist motor (16). The first wheel (20) and the second wheel (30) are driven to rotate by the pedal (15) and / or the power assist motor (16).

7. A sprocket structure according to claim 6, characterized in that, Both the first wheel (20) and the second wheel (30) have a receiving groove (21) on their outer periphery. When the chain (40) is engaged with the first wheel (20), the chain (40) is placed in the receiving groove (21).

8. A sprocket structure according to claim 7, characterized in that, The chain (40) is provided with a plurality of first engagement protrusions (41) evenly arranged, and a first engagement groove (42) is formed between adjacent first engagement protrusions (41); the receiving groove (21) is provided with a second engagement protrusion (22) that engages and matches the first engagement groove (42), and a second engagement groove (23) that engages and matches the first engagement protrusion (41) is formed between adjacent second engagement protrusions (22).

9. A sprocket structure according to claim 8, characterized in that, At least one guide groove (24) communicating with the outside is provided at the bottom of the second meshing groove (23) to reduce meshing friction.

10. A power-assisted bicycle, characterized in that, Includes the sprocket structure as described in any one of claims 1-9.

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