Motorcycle bottom fork assembly and motorcycle

Abstract

The motorcycle bottom fork assembly comprises a left rocker arm, a right rocker arm and a chain box installed on the left rocker arm, a cross beam is arranged between the right rocker arm and the left rocker arm, the right rocker arm and the left rocker arm are connected through the cross beam, and the chain box comprises an inner box part and an outer box part. The outer box part and the inner box part span the left rocker arm and are fixedly connected with the left rocker arm through the outer box part; according to the motorcycle bottom fork assembly and the motorcycle, under the condition that the rear rocker arm adopts integrally-formed light-weight and miniaturized processing, it can be guaranteed that the overall rigidity and strength of the rear rocker arm cannot be reduced, the rear rocker arm is stable in structure, the chain box and the mud guard arranged on the bottom fork can be connected with the rocker arm body, assembly is more concise and convenient, and the service life of the rear rocker arm is prolonged. The structure stability is good, the chain box and the fender can shield key performance components, damage to the performance components and shortening of the service life caused by tire muddy water splashing are avoided, and the muddy water blocking efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of motorcycles, in particular to a motorcycle flat fork assembly and a motorcycle. Background Art

[0002] The motorcycle swingarm is an important part of the motorcycle suspension. It connects the rear wheel with the body, frame, shock absorber and other components, and transmits and bears the force and torque of the frame and rear wheel. The force generated by the vehicle during acceleration, deceleration and braking needs to be transmitted through the swingarm to bear the pressure of the vehicle body, fix the rear wheel and maintain the stability of the vehicle body. From the perspective of styling, the swingarm is mainly divided into two types: single swingarm and double swingarm. The double swingarm is the most common type of swingarm with four sides, of which the short side is connected to the motorcycle frame through a bearing, and the other short side is the rear axle around which the rear wheel rotates. The double swingarm has a simple structure and can achieve better torsional strength with less material, which helps to make the motorcycle lighter.

[0003] In the existing art, following current technological trends, motorcycle swingarms are being lightweighted and miniaturized. Reducing the weight of the swingarm lowers the motorcycle's center of gravity, helping to maintain vehicle stability during braking, improving braking effectiveness, and reducing the motorcycle's rotational inertia, making it more maneuverable during cornering and enhancing maneuverability. However, simply lightweighting the swingarm reduces the rigidity of the main swingarm. Adding a chain box and rear fender increases the rigidity requirements of both, reducing structural stability, increasing the complexity of design, manufacturing, and assembly, and making industrial design difficult.

[0004] Therefore, there is an urgent need to develop a motorcycle flat fork assembly that can ensure that the overall rigidity of the rear swing arm will not decrease when the rear swing arm is made of one-piece lightweight and miniaturized processing, the rear swing arm structure is stable, the structure and appearance design are combined, the structural volume is greatly reduced, the industrial aesthetics is stronger, and the difficulty of design, manufacturing, and assembly is reduced. Utility Model Content

[0005] In view of this, the purpose of the present invention is to provide a motorcycle flat fork assembly and a motorcycle, which can ensure that the overall rigidity of the rear swing arm will not decrease when the rear swing arm adopts an integrated lightweight and miniaturized processing, the rear swing arm structure is stable, the structure and appearance design are combined, the structural volume is greatly reduced, the industrial aesthetics is stronger, and the difficulty of design, manufacturing and assembly is reduced.

[0006] The motorcycle flat fork assembly of the utility model includes a left rocker arm, a right rocker arm and a chain box installed on the left rocker arm. A crossbeam is provided between the right rocker arm and the left rocker arm and is connected by the crossbeam. The chain box includes an inner box part and an outer box part. The outer box part and the inner box part span the left rocker arm and are fixedly connected to the left rocker arm through the outer box part.

[0007] Furthermore, the inner box portion is arranged forward relative to the outer box portion, the surface of the outer box portion is in a stepped arc shape, and the inner box portion and the outer box portion are integrally formed and connected through an arched transition.

[0008] Furthermore, it also includes a fender, which is in a bird's beak shape and forms an inwardly concave surface in the middle. Fender mounting holes are provided on both sides of the inwardly concave surface. The fender is mounted on the top of the right rocker arm and the top of the outer box portion and is located behind the crossbeam.

[0009] Furthermore, the crossbeam is provided with a support seat connected to the rear suspension, and the right rocker arm and the left rocker arm are both provided with a bushing portion and a rear wheel axle mounting portion. The right rocker arm protrudes upward to form a bow-shaped protrusion, and the left rocker arm is in the shape of an arrow with the arrow portion facing the rear of the rear rocker arm body.

[0010] Furthermore, a fender mounting portion is provided at the top of the arched protrusion of the right rocker arm and the top of the outer box portion, the arrow portion of the left rocker arm is provided at the front end of the rear wheel axle mounting portion, the outer side of the left rocker arm is recessed inward to form a chain box mounting portion, the outer box portion is installed on the outer side of the left rocker arm, and a limiting component for limiting the front end of the inner box portion is provided on the rotating shaft sleeve portion of the left rocker arm.

[0011] Furthermore, the crossbeam is provided with a limiting rib and a limiting hole on the side of the support seat close to the left rocker arm for laterally limiting the rear end of the inner box part. The limiting rib includes a first longitudinal rib and a second longitudinal rib. The spacing between the first longitudinal rib and the second longitudinal rib is equal to the thickness of the rear end of the inner box part. The rear end of the inner box part is provided with a tenon that matches the limiting hole.

[0012] Furthermore, a drainage groove I is formed on the crossbeam between the right rocker arm and the support seat, and a drainage groove II is formed on the crossbeam between the support seat and the inner box portion, and the bottom of the drainage groove I and the bottom of the drainage groove II are on the same horizontal line.

[0013] Furthermore, a chain guard is provided at the top of the front end of the left rocker arm, and the chain guard protrudes toward the support seat at the crossbeam, and an auxiliary drainage groove is formed on the crossbeam between the chain guard and the inner box part.

[0014] Furthermore, the concave curved surface of the fender has a drainage gap I on the side close to the right rocker arm, and the concave curved surface has a drainage gap II on the side close to the left rocker arm. A drainage gap is formed between the drainage gap I and the drainage groove I, and a drainage gap is formed between the drainage gap II and the drainage groove II.

[0015] The utility model also provides a motorcycle, on which the above-mentioned motorcycle flat fork assembly is installed.

[0016] The beneficial effects of the present invention are as follows: the motorcycle flat fork assembly and the motorcycle of the present invention can ensure that the overall rigidity of the rear swing arm will not decrease when the rear swing arm adopts an integrally formed lightweight and miniaturized processing, and the rear swing arm structure is stable. The chain box and the mudguard arranged on the flat fork can be connected to the rocker arm body, and the assembly is simpler and more convenient, and the structural stability is good. The chain box and the mudguard can shield key performance components, avoid damage to performance components and reduction in service life caused by splashing of mud and water from tires, and improve mud and water blocking efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0018] Figure 1 This is a schematic diagram of the structure of the utility model Figure I ;

[0019] Figure 2 This is a schematic diagram of the structure of the utility model Figure II ;

[0020] Figure 3 The side view of the utility model Figure I ;

[0021] Figure 4 This is a schematic diagram of the right rocker arm structure of the present utility model;

[0022] Figure 5 This is the side view of the utility model Figure II ;

[0023] Figure 6 This is a schematic diagram of the chain box structure of the utility model Figure I ;

[0024] Figure 7 This is a schematic diagram of the chain box structure of the utility model Figure II ;

[0025] Figure 8 This is an assembly diagram of the utility model Figure I ;

[0026] Figure 9 This is an assembly diagram of the utility model Figure II ;

[0027] Figure 10 It is a front view of the utility model;

[0028] Figure 11 This is a cross-sectional view of the utility model Figure I ;

[0029] Figure 12 This is a cross-sectional view of the utility model Figure II . DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0031] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0032] As shown in the figure: the motorcycle fork assembly of this embodiment includes a left rocker arm 2, a right rocker arm 1 and a chain box 4 installed on the left rocker arm 2, a crossbeam 3 is provided between the right rocker arm 1 and the left rocker arm 2 and connected by the crossbeam 3, the chain box 4 includes an outer box part 401 and an inner box part 402, the outer box part 401 and the inner box part 402 span the left rocker arm 2 and are fixedly connected to the left rocker arm 2 through the outer box part 401; the chain box 4 is an important part of the motorcycle transmission system, and its main function is to protect the motorcycle chain and prevent the chain from being damaged by erosion of external factors such as mud, water, etc., and at the same time it can also reduce the noise of the chain when running at high speed and improve riding comfort. The chain box 4 includes an outer box part 401 and an inner box part 402 The outer box part 401 and the inner box part 402 span the left rocker arm 2. The design of spanning the left rocker arm 2 means that the outer box part 401 and the inner box part 402 are in the shape of a half-shell as a whole, and the outer box part 401 and the inner box part 402 span the two sides of the left rocker arm 2 in a half-cover manner; the left rocker arm 2, the right rocker arm 1 and the crossbeam 3 are integrally formed and are all hollow structures. The hollow structure means that the flat fork adopts a hollow design. This structural design can improve the strength and rigidity of the material while maintaining structural strength, while reducing weight and optimizing performance. The motorcycle flat fork structure of this scheme can be made of thin-walled aluminum alloy for one-piece hollow casting. The hollow structure has a strong ability to withstand bending moments at the cross section, thereby improving the overall rigidity of the flat fork.

[0033] In this embodiment, the inner box portion 402 is arranged forwardly relative to the outer box portion 401, and the surface of the outer box portion 401 is in a stepped arc shape. The inner box portion 402 and the outer box portion 401 are integrally formed and connected by an arched transition; the surface of the outer box portion 401 is in a stepped arc shape, and the stepped shape means that the surface of the outer box portion 401 forms a stepped arc shape in the height direction of the vehicle body, which can improve the structural strength of the outer box portion 401, ensure that the outer box portion 401 can withstand greater impact and torque during vehicle driving, avoid deformation of the outer box portion 401, and increase its protection ability for the chain; the inner box portion 402 and the outer box portion 401 are connected by an arched transition, which can ensure the overall firmness of the chain box 4, not only provides good mechanical properties, but also helps to improve the durability of the chain box 4 and the overall appearance of the appearance. Figure 7 As shown, the inner box portion 402 is further provided with three parallel triangular reinforcing ribs 410 at the arched transition portion. The triangular reinforcing ribs 410 can enhance the rigidity of the outer flange surface of the inner box portion 402 at the arched transition portion.

[0034] In this embodiment, a fender 5 is further included. The fender 5 is in a bird's beak shape and forms an inwardly concave surface 501 in the middle. Fender mounting holes 502 are provided on both sides of the inwardly concave surface 501. The fender 5 is mounted on the top of the right rocker arm 1 and the top of the outer box portion 401 and is located behind the crossbeam 3. The inwardly concave surface 501 in the middle of the fender 5 is designed to improve the aerodynamic performance of the vehicle at this location during driving and reduce wind resistance. The fender 5 is located behind the crossbeam 3 and can also effectively block mud and water when driving in rainy days, keep the vehicle body clean, and improve the structural strength and durability of the fender 5.

[0035] In this embodiment, the crossbeam 3 is provided with a support seat 301 connected to the rear suspension, and the right rocker arm 1 and the left rocker arm 2 are both provided with a shaft sleeve portion and a rear wheel axle mounting portion. The right rocker arm 1 is raised upward to form a bow-shaped raised portion 110, and the left rocker arm 2 is in the shape of an arrow with the arrow portion 204 facing the rear of the rear rocker arm body; Figure 4 As shown, the right rocker arm 1 is in an upwardly protruding bow shape, the shaft sleeve portion is provided at the front ends of the right rocker arm 1 and the left rocker arm 2 along the length direction of the vehicle body, and the rear wheel axle mounting portion is provided at the rear ends of the right rocker arm 1 and the left rocker arm 2 along the length direction of the vehicle body. The right rocker arm 1 protrudes upward to form a bow-shaped protrusion 110, and upward protrusion refers to upward protrusion along the height direction of the vehicle body. The right rocker arm 1 adopts an upwardly protruding bow structure, which can effectively improve the supporting stiffness and strength of the right rocker arm 1 when the main body of the right rocker arm 1 is subjected to the vertical force transmitted by the rear wheel; as shown Figure 4 and Figure 5As shown, the neck of the arrow portion 204 is arranged facing the brake limiting boss 107 on the right rocker arm 1. The neck of the arrow portion 204 is the part close to the non-sharp end of the arrow. The brake limiting boss 107 is a structural design, and its main function is to limit the range of movement of the brake, ensure the stability and safety of the brake during operation, help to improve the overall stability of the rear fork and the positioning accuracy of the brake, prevent the brake from excessive movement or falling off under extreme conditions, thereby ensuring the safety of motorcycle driving; the outer diameter of the left rocker arm sleeve portion 201 is tangentially connected to the front end of the left rocker arm 2. When the rear wheel is subjected to a large impact load and rapid acceleration and deceleration, the torque transmitted through the transmission chain is large. The layout of the left rocker arm 2 can improve the overall rigidity of the left rocker arm 2.

[0036] In this embodiment, the top of the right rocker arm arched protrusion 110 and the outer box portion 401 are both provided with a fender mounting portion, the arrow portion 204 of the left rocker arm 2 is provided at the front end of the left rocker arm rear wheel axle mounting portion 202, the outer side of the left rocker arm 2 is recessed inward to form a chain box mounting portion 203, the outer box portion 401 is installed on the outer side of the left rocker arm 2, and the left rocker arm shaft sleeve portion 201 is provided with a limiting component for limiting the front end of the inner box portion 402; the outer box portion 40 The top of the outer box 401 is recessed inward to form the fender mounting portion I 403. The fender mounting portion I 403 is provided with a groove reinforcement rib 408 that fits in with the fender 5. The top of the outer box 401 is recessed inward to form a serrated boss 407 that cooperates with the groove reinforcement rib 408 to increase the structural strength of the fender 5 and the outer box 401. The top structure of the outer box 401 on the right rocker arm 1 is the same as that of the outer box 401. To repeat; in this solution, the limiting assembly on the left rocker arm shaft sleeve 201 includes a positioning rib 205 and a positioning pin hole 206, and the front end of the inner box part 402 is correspondingly provided with a positioning plate 405 and a positioning pin column 404, which can further limit and fix the inner box part 402, especially the front end of the inner box part 402, to prevent the inner box part 402 from loosening during driving. The limiting assembly can also adopt other structures with limiting functions, which are not repeated here; the chain box mounting part 203 can be installed with a chain box 4 having an outer box part 401 and an inner box part 402, and the outer box part 401 and the inner box part 402 span the left rocker arm 2 and the outer box part 401 is fixedly connected to the left rocker arm 2 through the chain box mounting part 203. The fixed connection method can be to open opposite bolt holes on the outer box part 401 and the chain box mounting part 203, and use bolts for fixed connection to facilitate the disassembly, replacement and maintenance of the chain box 4. Other fixed connection methods can also be adopted, which are not repeated here.

[0037] In this embodiment, the chain box mounting portion 203 is configured as a curved sink, and the bottom of the outer box portion 401 is an arc that conforms to the inner edge of the curved sink. The outer box portion 401 is provided with a grid-shaped reinforcement rib 409 on the side in contact with the chain box mounting portion 203, which can increase the structural strength of the outer box portion 401 installed on the left rocker arm 2. The outer edge of the curved sink is provided with an arc-shaped reinforcement rib 7, which transitions in an arc shape from the connection between the left rocker arm 2 and the crossbeam to between the crossbeam 3 and the outer edge surface of the rear tire. The arc-shaped reinforcement rib 7 then extends parallel to the bottom of the left rocker arm 2 and transitions to the top of the left rocker arm 2 through an arc. When the left rocker arm 2 is restricted by the transmission chain, the size of the left rocker arm 2 is significantly reduced compared to the size of the right rocker arm 1. Under the premise of ensuring the lightweight of the flat fork, arranging the arc-shaped reinforcement rib on the chain box mounting portion 203 can effectively improve the rigidity of the chain box mounting portion 203 and ensure the stability of the overall structure of the chain box 4 and the left rocker arm 2.

[0038] In this embodiment, the crossbeam is provided with a limiting rib and a limiting hole 307 on the side of the support seat 301 close to the left rocker arm 2 for laterally limiting the rear end of the inner box portion 402. The limiting rib includes a first longitudinal rib 305 and a second longitudinal rib 306. The spacing between the first longitudinal rib 305 and the second longitudinal rib 306 is equal to the thickness of the rear end of the inner box portion 402. The rear end of the inner box portion 402 is provided with a tenon 406 that matches the limiting hole 307; Figure 8 As shown, the first longitudinal rib 305 is arranged on the crossbeam 3 near the side of the support seat 301, and the second longitudinal rib 306 is arranged on the crossbeam 3 near the side of the left rocker arm 2. The longitudinal arrangement of the limiting ribs means that they are arranged on the crossbeam 3 along the length direction of the vehicle body, and the limiting hole 307 is arranged between the second longitudinal rib 306 and the left rocker arm 2. The first longitudinal rib 305, the second longitudinal rib 306 and the limiting hole 307 can limit and fix the rear end of the inner box part 402, and cooperate with the limiting of the front end of the inner box part 402 to ensure that the inner box part 402 will not loosen or have relative displacement during driving, making driving safer.

[0039] In this embodiment, a drainage groove I 302 is formed on the crossbeam between the right rocker arm 1 and the support seat 301, and a drainage groove II 303 is formed on the crossbeam between the support seat 301 and the inner box portion 402, and the bottom of the drainage groove I 302 and the bottom of the drainage groove II 303 are on the same horizontal line; a chain guard 8 is provided on the top front end of the left rocker arm 2, and the chain guard 8 protrudes toward the support seat 301 on the side close to the crossbeam 3, and an auxiliary drainage groove 304 is formed on the crossbeam 3 between the chain guard and the inner box portion 402; the concave surface 501 of the fender 5 is provided with a drainage notch I 502 on the side close to the right rocker arm 1, and the concave surface 501 is provided with a drainage notch II 503 on the side close to the left rocker arm 2, a drainage gap is formed between the drainage notch I 502 and the drainage groove I 302, and a drainage gap is formed between the drainage notch II 503 and the drainage groove II 303; as shown Figure 10 As shown, the right rocker arm 1 is provided with a slope 9 for transition from the top of the arched protrusion 110 to the top of the crossbeam, and the concave surface 501 of the fender 5 overlaps with the slope 9 near the drainage notch Ⅰ502 of the right rocker arm 1 to form the drainage groove Ⅰ302. The concave surface 501 of the fender 5 is close to the drainage notch Ⅱ503 of the left rocker arm 2 and forms the drainage groove Ⅱ302 with the support seat 301 of the crossbeam 3 to the left of the first longitudinal rib 305 and the inner box part 402.

[0040] In this embodiment, the right rocker arm 1 is provided with a hollow structure 105 near the middle, and the cross section of the hollow structure 105 is trumpet-shaped, the opening of the trumpet is toward the outside of the right rocker arm 1, and the inner side of the right rocker arm 1 is provided with an inner reinforcing rib 106 at the edge of the hollow structure 105; the inner side of the right rocker arm 1 and the left rocker arm 2 refers to the side connected to the crossbeam 3, and the outer side of the inner side of the right rocker arm 1 and the left rocker arm 2 refers to the side not connected to the crossbeam 3; since the right rocker arm 1 adopts an upwardly convex bow structure, the volume of the right rocker arm 1 at the convex part is larger, that is, the surface area of the longitudinal section of the right rocker arm 1 at this place is larger, and an overly large right rocker arm 1 will lead to the overall mass of the flat fork The increase is not conducive to the lightweight design of the flat fork, so a hollow structure 105 is provided near the middle of the right rocker arm 1, and the cross-section of the hollow structure 105 is trumpet-shaped. The trumpet-mouth shape can provide better stress distribution, so that the right rocker arm 1 is more stable when bearing force, and the overall rigidity is enhanced. Moreover, when driving at high speeds, the trumpet-mouth shape can improve the air flow around the right rocker arm 1 and reduce air resistance. The inner side of the right rocker arm 1 is provided with an inner reinforcement rib 106 at the edge of the hollow structure 105. The inner reinforcement rib 106 can increase the rigidity and strength of the hollow structure 105, so that it can withstand greater loads and impact forces, and avoid deformation of the right rocker arm 1 at the hollow structure 105.

[0041] In this embodiment, the right rocker arm 1 includes an upper support beam 103 and a lower support beam 104, and the upper support beam 103 and the lower support beam 104 form the hollow structure 105 near the middle of the right rocker arm 1. The upper support beam 103 and the lower support beam 104 protrude toward the outside of the right rocker arm 1 to form a first reinforcing rib 108 and a second reinforcing rib 109. The first reinforcing rib 108 extends from the right rocker arm sleeve portion 101 through the upper support beam 103 and to the right rocker arm rear wheel axle mounting portion 102; the second reinforcing rib 109 extends from the right rocker arm sleeve portion 101 through the lower support beam 104 and to the tail of the right rocker arm 1; Figure 11 As shown, the upper support beam 103 and the lower support beam 104 are both hollow structures. In the height direction of the vehicle body, the cross-sectional height of the upper support beam 103 is 2 to 3 times the cross-sectional height of the lower support beam 104; the cross-sectional height of the upper support beam 103 is 1 to 2.5 times its own cross-sectional width; the ratio of the cross-sectional height of the lower support beam 104 to its own cross-sectional width is about 1; the cross-sectional height of the right rocker arm 1 near the right rocker arm sleeve part 101 is about 2 to 3 times the outer diameter of the right rocker arm sleeve part 101. The right rocker arm 1 is cast using the above-mentioned numerical ratio. When the right rocker arm 1 body is subjected to the vertical force, lateral force and torque transmitted by the rear wheel, the support and torsional rigidity of the right rocker arm 1 can be effectively improved.

[0042] In this embodiment, the upper support beam 103 forms the arched protrusion 110 of the right rocker arm 1, and the lower support beam 104 forms the arched recessed portion 111 of the right rocker arm 1. The top of the arched protrusion 110 of the upper support beam 103 is higher than the top of the support seat 301 and is located between the support seat 301 and the rear tire, and the bottom of the arched recessed portion 111 of the lower support beam 104 is located below the bottom of the cross beam 3; the right rocker arm 1 gradually transitions from the right rocker arm sleeve portion 101 to the arched protrusion 110, and the height of the top of the arched protrusion 110 is about 4 times the height of the right rocker arm rear wheel axle mounting portion 102, and the arched protrusion 110 then gradually transitions to the front end of the right rocker arm rear wheel axle mounting portion 102.

[0043] In this embodiment, the cross section of the cross beam 3 is approximately a parallelogram, the top and bottom of the cross beam 3 are low in the front and high in the back, the connection between the cross beam 3 and the right rocker arm 1 and the connection between the left rocker arm 2 are both curved transitions, and the bottom of the cross beam 3 is connected to the right rocker arm 1 and the left rocker arm 2 to form a curved bridge arch; Figure 4As shown, the top and bottom of the crossbeam 3 are lower in the front and higher in the back, which refers to the plane formed by connecting the center of the sleeve portion and the center of the rear wheel axle mounting portion. This plane forms an acute angle with the top and bottom of the crossbeam 3. The support seat 301 is provided with a rear suspension sleeve portion. The two ends of the rear suspension sleeve portion extend towards the front side of the crossbeam 3 to form two support seat reinforcement ribs 307 whose height gradually decreases toward the front side of the crossbeam 3. The above-mentioned arrangement of the crossbeam 3 can effectively improve the bearing strength of the crossbeam 3, the right rocker arm 1 and the left rocker arm 2 when the rear suspension system transmits a larger load to the crossbeam 3. In this embodiment, a motorcycle is also provided, and the motorcycle is equipped with the above-mentioned motorcycle flat fork assembly. When the flat fork is lightweight and miniaturized by adopting an integrated molding process, the left rocker arm 2 and the right rocker arm 1 in the flat fork are reinforced to ensure that the overall rigidity of the flat fork does not decrease. The flat fork structure is stable, and the structure is combined with the appearance design to greatly reduce the structural volume, enhance the industrial aesthetics, and reduce the difficulty of design, manufacturing, and assembly. The chain box 4 provided with an outer box part 401 and an inner box part 402 cooperates with the mudguard 5 to shield key performance components. The mud and water splashed by the rear tire flows through the gap between the mudguard 5 and the crossbeam into the drainage groove I, the drainage groove II and the auxiliary drainage groove and overflows, thereby avoiding damage to the performance components and reducing the service life due to the splash of tire mud and water, and improving the mud and water blocking efficiency.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model and are not limiting. Although the utility model is described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A motorcycle fork assembly, characterized by: It includes a left rocker arm, a right rocker arm and a chain box installed on the left rocker arm. A crossbeam is provided between the right rocker arm and the left rocker arm and they are connected through the crossbeam. The chain box includes an inner box part and an outer box part. The outer box part and the inner box part span the left rocker arm and are fixedly connected to the left rocker arm through the outer box part.

2. The motorcycle flat fork assembly according to claim 1, characterized in that: The inner box portion is arranged forward relative to the outer box portion, the surface of the outer box portion is in a stepped arc shape, and the inner box portion and the outer box portion are integrally formed and connected through an arched transition.

3. The motorcycle flat fork assembly according to claim 1, characterized in that: It also includes a fender, which is bird-beak-shaped and forms an inwardly concave surface in the middle. Fender mounting holes are provided on both sides of the inwardly concave surface. The fender is mounted on the top of the right rocker arm and the top of the outer box and is located behind the crossbeam.

4. The motorcycle flat fork assembly according to claim 1, characterized in that: The crossbeam is provided with a support seat connected to the rear suspension, and the right rocker arm and the left rocker arm are both provided with a bushing portion and a rear wheel axle mounting portion. The right rocker arm protrudes upward to form a bow-shaped protrusion, and the left rocker arm is in the shape of an arrow with the arrow portion facing the rear of the rear rocker arm body.

5. The motorcycle flat fork assembly according to claim 4, characterized in that: A fender mounting portion is provided at the top of the arched protrusion of the right rocker arm and the top of the outer box portion. The arrow portion of the left rocker arm is provided at the front end of the rear wheel axle mounting portion. The outer side of the left rocker arm is recessed inward to form a chain box mounting portion. The outer box portion is installed on the outer side of the left rocker arm. A limiting assembly for limiting the front end of the inner box portion is provided on the rotating shaft sleeve portion of the left rocker arm.

6. The motorcycle flat fork assembly according to claim 4, characterized in that: The crossbeam is provided with a limiting rib and a limiting hole on the side of the support seat close to the left rocker arm for laterally limiting the rear end of the inner box part. The limiting rib includes a first longitudinal rib and a second longitudinal rib. The spacing between the first longitudinal rib and the second longitudinal rib is equal to the thickness of the rear end of the inner box part. The rear end of the inner box part is provided with a tenon that matches the limiting hole.

7. The motorcycle flat fork assembly according to claim 4, characterized in that: A drainage groove I is formed on the crossbeam between the right rocker arm and the support seat, and a drainage groove II is formed on the crossbeam between the support seat and the inner box portion. The bottoms of the drainage groove I and the bottoms of the drainage groove II are on the same horizontal line.

8. The motorcycle flat fork assembly according to claim 4, characterized in that: A chain guard is provided at the top of the front end of the left rocker arm. The chain guard protrudes toward the support seat at the crossbeam, and an auxiliary drainage groove is formed on the crossbeam between the chain guard and the inner box part.

9. The motorcycle flat fork assembly according to claim 3, characterized in that: The concave surface of the fender has a drainage gap I on the side close to the right rocker arm, and a drainage gap II on the side close to the left rocker arm. A drainage gap is formed between the drainage gap I and the drainage groove I, and a drainage gap is formed between the drainage gap II and the drainage groove II.

10. A motorcycle, characterized in that: The motorcycle is equipped with a motorcycle flat fork assembly as described in any one of claims 1 to 9.

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