A motorcycle engine mounting structure

Abstract

The application discloses a motorcycle engine mounting structure, which separates the crankcase of the engine from the transmission case, fixes the crankcase and the cylinder head on the frame, connects the transmission case with the crankcase through a first bearing to form a rotary connection relationship, connects the rear end of the transmission case to the frame through a rear shock absorber, and enables the whole transmission case and the rear wheel to rotate around the crankshaft center of the crankcase, so that the riding vibration and the engine shaking can be reduced and alleviated by the rear shock absorber, the vibration is prevented from being directly transmitted to the vehicle body, and the riding comfort of the user can be improved. In addition, the first bearing, the first shaft sleeve, the compression nut and the retainer ring are combined to limit the axial movement of the bearing, ensure that the bearing and the shaft sleeve are not separated, and ensure that the transmission case stably rotates around the crankshaft center of the crankcase. The axial stability of the bearing is further improved, and the reliability of power transmission and the stable operation of the transmission system are ensured.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of motorcycles, and particularly relates to a motorcycle engine mounting structure. BACKGROUND

[0002] At present, the users of scooters are increasing, and the users have higher and higher requirements for the comfort of the whole vehicle. The transmission case and the crankcase of most scooters are integrated, and the engine is directly fixed on the frame by bolts, so that the rigidity of the whole vehicle is higher, but the vibration of the engine, the shaking when the clutch is combined, and the vibration of the rear wheel corresponding to the bottom surface (hereinafter referred to as “traveling vibration”) are all directly transmitted to the frame through the connecting rubber sleeve of the engine and the frame, so that the rider will feel greater vibration and shaking during traveling.

[0003] In recent years, with the popularity of scooters, users have increasingly high demands for riding comfort. However, most scooters on the market currently use an engine mounting structure with significant defects: the transmission case and the crankcase are usually designed in an integrated manner and are directly fixed to the frame by rigid bolts. Although this structure can enhance the overall rigidity of the vehicle, it causes the vibration of the engine during operation, the impact and shaking when the clutch is combined, and the traveling vibration generated by the contact between the rear wheel and the ground to be directly transmitted to the frame through the rigid connection path.

[0004] Specifically, in the prior art, the connection between the engine and the frame mainly relies on rubber buffer bushings for vibration reduction. However, due to the integrated design of the transmission case and the crankcase, it is difficult to effectively isolate the vibration energy. The damping performance of the rubber bushing is limited, especially when dealing with high-frequency vibration and complex load conditions, the vibration absorption effect is significantly reduced, resulting in large vehicle body vibration amplitude and poor riding comfort. In addition, the rigid coupling of the transmission system and the frame also exacerbates the instability during power transmission, affecting transmission efficiency and component lifespan.

[0005] Some improvement schemes in the industry attempt to alleviate the vibration problem by optimizing the layout of the buffer bushing or adding local damping elements, but these measures are mostly limited to local optimization and cannot fundamentally solve the defects of single vibration transmission path and insufficient energy absorption caused by the integrated structure of the transmission case and the crankcase. Therefore, there is an urgent need for an engine mounting structure that can achieve vibration isolation and stable power transmission to improve user experience and prolong vehicle service life. SUMMARY

[0006] The problem to be solved by the present application is to provide a motorcycle engine mounting structure that can effectively separate the crankcase and the transmission case of the engine, reduce the vibration and shaking transmitted to the frame by the whole engine and the transmission part, and improve the comfort during traveling, while ensuring the reliability of power transmission and the smooth operation of the transmission system.

[0007] In order to solve the above technical problems, the motorcycle engine mounting structure provided by the present application comprises a frame, a crankcase, a transmission case and a rear shock absorber, the crankcase is fixedly provided with an upper case hanger, a lower case hanger and a cylinder head hanger, the upper case hanger, the lower case hanger and the cylinder head hanger are connected with the frame respectively; the transmission case is rotatably mounted on the crankcase through a first bearing around the crankshaft center of the crankcase; the rear end of the transmission case is fixedly provided with a rear hanger, the rear hanger is connected with the lower end of the rear shock absorber, and the upper end of the rear shock absorber is connected with the frame; the left side of the crankcase is fixedly connected with a first shaft sleeve coaxially arranged with the crankshaft center of the crankcase through a fastening bolt, the first bearing is interference-fitted in the transmission case, and the inner ring of the first bearing is connected with the outer ring of the first shaft sleeve; the crankshaft of the crankcase passes through the inner ring of the first shaft sleeve in sequence and extends into the transmission case; the transmission case is provided with a check ring, the check ring abuts against the end face of the outer ring of the first bearing away from the crankcase; the transmission case is provided with a check ring groove for mounting the check ring; the end of the first shaft sleeve away from the crankcase is threadedly connected with a compression nut, and the compression nut abuts against the end face of the inner ring of the first bearing away from the crankcase.

[0008] As a preferred scheme of the present application, the crankcase hanger assembly composed of the upper case hanger, the lower case hanger and the cylinder head hanger is provided with two groups, and the two groups of the crankcase hanger assembly are arranged on the left and right sides of the crankcase.

[0009] As a preferred scheme of the present application, rubber buffer bushings are interference-fitted in the upper case hanger, the lower case hanger and the cylinder head hanger;

[0010] The upper case hanger is connected with the frame through a first support shaft sleeve, a first bolt and a first nut; wherein the first support shaft sleeve is arranged between the upper case hangers on the left and right sides, and the left and right ends of the first support shaft sleeve abut against the rubber buffer bushings on the upper case hangers on the left and right sides respectively; the first bolt penetrates through the first support shaft sleeve and the rubber buffer bushings on the upper case hangers;

[0011] The cylinder head hanger is connected with the frame through a second support shaft sleeve, a second bolt and a second nut; wherein the second support shaft sleeve is arranged between the cylinder head hangers on the left and right sides, and the left and right ends of the second support shaft sleeve abut against the rubber buffer bushings on the cylinder head hangers on the left and right sides respectively; the second bolt penetrates through the second support shaft sleeve and the rubber buffer bushings on the cylinder head hangers;

[0012] The box lower hanging is connected on the frame through a rocker, a third bolt and a fourth bolt; wherein the rocker is arranged on the lower side of the crankcase, the rocker is provided with a first connecting part and a second connecting part, the first connecting part is arranged between the left and right box lower hangings, and the left and right ends of the first connecting part are respectively abutted with the rubber buffer bushings on the left and right box lower hangings; the third bolt is connected with the first connecting part through the rubber buffer bushings on the box lower hanging, and the first connecting part is provided with a first threaded hole for screwing with the third bolt; the fourth bolt is connected with the second connecting part through the frame, and the second connecting part is provided with a second threaded hole for screwing with the fourth bolt.

[0013] As a preferred scheme of the present application, the inner hole diameter of the first shaft sleeve is larger than the outer diameter of the crankshaft of the crankcase, and a dynamic sealing structure is arranged between the first shaft sleeve and the crankshaft of the crankcase.

[0014] As a preferred scheme of the present application, the end of the first shaft sleeve close to the crankcase is fixedly provided with a mounting plate, the mounting plate is provided with a mounting hole for connecting the fastening bolt, and a sealing ring is arranged between the contact surface of the mounting plate and the crankcase.

[0015] As a preferred scheme of the present application, a continuously variable speed driving wheel is arranged in the transmission case, and the continuously variable speed driving wheel is mounted on the crankshaft of the crankcase; a crankshaft sleeve is sleeved on the crankshaft of the crankcase, the outer diameter of the crankshaft sleeve is smaller than the inner hole diameter of the first shaft sleeve, and the end face of the continuously variable speed driving wheel close to the crankcase abuts against the end face of the crankshaft sleeve.

[0016] As a preferred scheme of the present application, a rocker arm is arranged on the right side of the crankcase, the rocker arm is rotatably mounted on the crankcase through a second bearing around the center of the crankshaft of the crankcase; a connecting block is arranged between the transmission case and the rocker arm, the transmission case is connected with the left end of the connecting block through a fifth bolt, and the end of the rocker arm away from the second bearing is connected with the right end of the connecting block through a sixth bolt.

[0017] As a preferred scheme of the present application, the second bearing is interference-pressed on the right side of the crankcase, the outer side cover of the second bearing is provided with an oil seal, the oil seal is fixedly connected with the crankcase, the inner hole of the oil seal is sleeved with a second shaft sleeve coaxially arranged with the crankshaft center of the crankcase, the inner end of the second shaft sleeve is pressed on the second bearing, a screw and a third nut are arranged on the rocker arm, the unthreaded part of the screw is sequentially inserted into the inner ring of the second shaft sleeve and the inner ring of the second bearing, and the threaded part of the screw is threadedly connected with the third nut through the rocker arm.

[0018] As a preferred scheme of the present application, the right end of the connecting block is fixedly connected with a rear fork through a seventh bolt, the rear fork is connected with the axle of the wheel, and the output shaft of the transmission case sequentially passes through the axle of the wheel, the rear fork and is threadedly connected with a fourth nut at the end thereof.

[0019] As a preferred scheme of the present application, the rear shock absorbers are arranged in a symmetrical manner on the left and right sides of the vehicle, the upper ends of the rear shock absorbers are connected to the frame through eighth bolts and fifth nuts, the lower end of the rear shock absorber on the left side is connected to the rear hanger through a ninth bolt, and the lower end of the rear shock absorber on the right side is connected to the rear fork through a tenth bolt.

[0020] The motorcycle engine mounting structure of the embodiment of the present application has the following beneficial effects compared with the prior art:

[0021] (1) The motorcycle engine mounting structure of the embodiment of the present application separates the crankcase of the engine from the transmission case, fixes the crankcase and the cylinder head on the frame, connects the rear end of the transmission case to the frame through the rear shock absorber, so that the entire transmission case and the rear wheel can rotate around the crankshaft center of the crankcase, and the driving vibration and the engine shaking can be reduced and alleviated by the rear shock absorber, thereby preventing the vibration from being directly transmitted to the vehicle body and improving the riding comfort of the user.

[0022] (2) The motorcycle engine mounting structure of the embodiment of the present application is designed by combining the first shaft sleeve, the pressing nut, the retainer and the first bearing, so as to limit the axial movement of the bearing, ensure that the bearing and the shaft sleeve are not separated, and ensure that the transmission case stably rotates around the crankshaft center of the crankcase. The axial stability of the bearing is further enhanced, and the reliability of power transmission and the stable operation of the transmission system are ensured. BRIEF DESCRIPTION OF DRAWINGS

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below.

[0024] Figure 1 This is a schematic diagram of the motorcycle engine mounting structure according to an embodiment of the present invention;

[0025] Figure 2 It is at Figure 1 The diagram shown is a structural schematic with the frame removed.

[0026] Figure 3 It is an exploded view of the crankcase and the rotating parts consisting of the transmission case, rocker arm, wheels, connecting blocks and rear swingarm;

[0027] Figure 4 It is a cross-sectional view of the crankcase connected to the rotating part consisting of the transmission case, rocker arm, wheel, connecting block and rear swingarm;

[0028] Figure 5 This is an exploded view of the connection between the crankcase and the chassis;

[0029] Figure 6 This is a schematic diagram showing the connection between the rear shock absorber and the frame, rear suspension, and rear swingarm.

[0030] Marked in the image:

[0031] Frame 1; Crankcase 2; Transmission 3; Rear Shock Absorber 4; Upper Chassis Suspension 5; Lower Chassis Suspension 6; Cylinder Head Suspension 7; First Bearing 8; Crankshaft 9; Rear Suspension 10; Rubber Buffer Bushing 11; First Support Bushing 12; First Bolt 13; First Nut 14; Second Support Bushing 15; Second Bolt 16; Second Nut 17; Cradle 18; First Connecting Part 181; Second Connecting Part 182; Third Bolt 19; Fourth Bolt 20; Fastening Bolt 21; First Bushing 22; Continuously Variable Transmission (CVT) 23. Wheel; 24. Retaining ring; 25. Compression nut; 26. Rocker arm; 27. Second bearing; 28. Connecting block; 29. ​​Fifth bolt; 30. Sixth bolt; 31. Second bushing; 32. Screw; 33. Third nut; 34. Seventh bolt; 35. Rear swing fork; 36. Wheel; 37. Axle; 38. Output shaft; 39. Fourth nut; 40. Eighth bolt; 41. Fifth nut; 42. Ninth bolt; 43. Tenth bolt; 44. Dynamic seal structure; 45. Mounting plate; 46. Sealing ring; 47. Crankshaft bushing; 48. Shoulder; 49. Oil seal. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., used to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and for 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, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0034] like Figures 1 to 6 As shown, this is a preferred embodiment of the present invention.

[0035] A motorcycle engine mounting structure includes a frame 1, a crankcase 2, a transmission case 3, and a rear shock absorber 4. The crankcase 2 is fixedly provided with an upper suspension 5, a lower suspension 6, and a cylinder head suspension 7, which are respectively connected to the frame 1. The transmission case 3 is rotatably mounted on the crankcase 2 around the crankshaft 9 of the crankcase 2 via a first bearing 8. A rear suspension 10 is fixedly provided at the rear end of the transmission case 3, which is connected to the lower end of the rear shock absorber 4, and the upper end of the rear shock absorber 4 is connected to the frame 1. Therefore, according to the motorcycle engine mounting structure of the present invention, the crankcase 2 and the transmission box 3 of the engine are separated, so that the crankcase 2 and the cylinder head are fixed on the frame 1. The transmission box 3 is connected to the crankcase 2 through the first bearing 8 to form a rotational connection relationship. At the same time, the rear end of the transmission box 3 is connected to the frame 1 through the rear shock absorber 4, so that the entire transmission box 3 and the rear wheel can rotate around the crankshaft 9 of the crankcase 2. In this way, the vibration of the ride and the vibration of the engine can be reduced and mitigated by the rear shock absorber 4, preventing the vibration from being directly transmitted to the vehicle body, and thus improving the riding comfort of the user.

[0036] In this embodiment, as Figure 3 and Figure 4As shown, a first bushing 22, coaxially arranged with the center of the crankshaft 9 of the crankshaft housing 2, is fixedly connected to the left side of the crankcase 2 by fastening bolts 21 to ensure precise alignment between the transmission housing 3 and the crankshaft 9 of the crankcase 2; the first bearing 8 is preferably a tapered roller bearing, which is press-fitted into the transmission housing 3, and the inner ring of the first bearing 8 is fitted with the outer ring of the first bushing 22, so that the first bearing 8 and the first bushing 22 fit tightly together, providing good load-bearing capacity and stability, and can withstand large radial and axial loads. Furthermore, the crankshaft 9 of the crankcase 2 passes through the inner ring of the first bushing 22 and extends into the transmission case 3, realizing a direct power connection between the crankcase 2 and the transmission case 3. The transmission case 3 is equipped with a retaining ring 24, which abuts against the end face of the outer ring of the first bearing 8 away from the crankcase 2, thereby restricting the axial movement of the bearing's outer ring and preventing axial force from causing the bearing to loosen. To facilitate the installation and removal of the retaining ring 24, the transmission case 3 is provided with a retaining ring groove for its installation. A clamping nut 25 is threaded to the end of the first bushing 22 away from the crankcase 2. The clamping nut 25 abuts against the end face of the inner ring of the first bearing 8 away from the crankcase 2, thus more firmly locking the first bearing 8 onto the first bushing 22. Compared to using a retaining ring to restrict the axial movement of the bearing's inner ring, this method has advantages such as stronger axial load-bearing capacity, greater stability and safety, and less axial movement of the bearing.

[0037] It can also be understood that the clamping nut 25 and the retaining ring 24 work together to limit the axial movement of the bearing, ensure that the bearing and the bushing do not separate, and ensure that the transmission box 3 rotates stably around the crankshaft 9 of the crankcase 2; further enhancing the axial stability of the bearing, ensuring the reliability of power transmission and the smooth operation of the transmission system.

[0038] For example, such as Figure 5 As shown, the crankcase 2 suspension assembly, consisting of the upper suspension 5, the lower suspension 6, and the cylinder head suspension 7, is provided in two sets, with the two sets of crankcase 2 suspension assemblies arranged on the left and right sides of the crankcase 2. These crankcase 2 suspension assemblies jointly bear the responsibility of supporting and fixing the crankcase 2, ensuring its stability during vehicle operation.

[0039] For example, such as Figure 5 As shown, rubber buffer bushings 11 are press-fitted into the upper suspension 5, the lower suspension 6, and the cylinder head suspension 7 of the crankcase. These rubber buffer bushings 11 have good elasticity and damping properties, which can effectively absorb and mitigate vibrations and shocks from the crankcase 2 during operation, thereby reducing the vibrations transmitted to the vehicle body.

[0040] In some embodiments, the connections between the upper suspension 5, the lower suspension 6, and the cylinder head suspension 7 and the frame 1 are specifically as follows:

[0041] like Figure 5 As shown, the suspension 5 on the box body is connected to the frame 1 via a first support bushing 12, a first bolt 13, and a first nut 14. The first support bushing 12 is positioned between the left and right suspension 5s on the box body, with its left and right ends abutting against the rubber buffer bushings 11 on the suspension 5s on both sides, to prevent displacement of the rubber buffer bushings 11 during the tightening of the first bolt 13 and the first nut 14. The first bolt 13 passes through the first support bushing 12 and the rubber buffer bushings 11 on the suspension 5s, and, in conjunction with the first nut 14, fixes the suspension 5 on the box body to the frame 1. This through-connection method ensures a tight fit between the suspension 5 and the frame 1, forming a stable connection structure.

[0042] like Figure 5 As shown, the cylinder head hanger 7 is connected to the vehicle frame 1 via a second support bushing 15, a second bolt 16, and a second nut 17. The second support bushing 15 is positioned between the left and right cylinder head hangers 7, with its left and right ends abutting against the rubber buffer bushings 11 on both sides of the cylinder head hanger 7 to prevent displacement of the rubber buffer bushings 11 during the tightening of the second bolt 16 and the second nut 17. The second bolt 16 passes through the second support bushing 15 and the rubber buffer bushings 11 on the cylinder head hanger 7, and, in conjunction with the second nut 17, fixes the cylinder head hanger 7 to the vehicle frame 1. This through-connection method ensures a tight fit between the cylinder head hanger 7 and the vehicle frame 1, forming a stable connection structure.

[0043] like Figure 5As shown, the lower suspension 6 of the crankcase 2 is connected to the frame 1 via a rocker arm 18, a third bolt 19, and a fourth bolt 20. The rocker arm 18 is located on the lower side of the crankcase 2 and has a first connecting portion 181 and a second connecting portion 182. The first connecting portion 181 is positioned between the left and right lower suspensions 6 of the crankcase 2, and its left and right ends respectively abut against the rubber buffer bushings 11 on the lower suspensions 6 of the crankcase 2 on both sides to prevent the rubber buffer bushings 11 from being tightened by the third bolt 19. During the process, displacement occurs; the third bolt 19 passes through the rubber buffer bushing 11 on the lower suspension 6 of the box and connects to the first connecting part 181, the first connecting part 181 is provided with a first threaded hole for threaded connection with the third bolt 19; the fourth bolt 20 passes through the frame 1 and connects to the second connecting part 182, the second connecting part 182 is provided with a second threaded hole for threaded connection with the fourth bolt 20. This through connection method makes the lower suspension 6 of the box, the rocker arm 18 and the frame 1 fit together tightly to form a stable connection structure.

[0044] For example, such as Figure 3 and Figure 4 As shown, the inner diameter of the first bushing 22 is larger than the outer diameter of the crankshaft 9 of the crankcase 2. A dynamic sealing structure 44 is provided between the first bushing 22 and the crankshaft 9 of the crankcase 2 to prevent the lubricating oil of the transmission case from mixing with the lubricating oil of the crankcase.

[0045] For example, such as Figure 3 As shown, to facilitate the fixing of the first bushing 22 to the crankcase 2, a mounting plate 45 is fixedly provided at one end of the first bushing 22 near the crankcase 2. The mounting plate is provided with mounting holes for the fastening bolts 21 to be connected. Furthermore, a sealing ring 46 is provided between the contact surface of the mounting plate 45 and the crankcase 2 to prevent the lubricating oil of the transmission case and the crankcase from leaking outward.

[0046] For example, such as Figure 3 and Figure 4 As shown, the transmission case 3 contains a transmission system, and the continuously variable transmission (CVT) drive wheel 23 in the transmission system is mounted on the crankshaft 9 of the crankcase 2, thereby transmitting the engine's power to the transmission system through the crankshaft 9 to drive the vehicle. Furthermore, to adjust the step difference of the CVT drive wheel, a crankshaft sleeve 47 is fitted onto the crankshaft 9 of the crankcase 2. The outer diameter of the crankshaft sleeve 47 is smaller than the inner diameter of the first sleeve 22, and the end face of the CVT drive wheel 23 near the crankcase 22 abuts against the end face of the crankshaft sleeve 47.

[0047] For example, such as Figure 3 and Figure 4As shown, a rocker arm 26 is provided on the right side of the crankcase 2. The rocker arm 26 is rotatably mounted on the crankcase 2 around the center of the crankshaft 9 of the crankcase 2 via a second bearing 27. A connecting block 28 is provided between the transmission case 3 and the rocker arm 26. The transmission case 3 is connected to the left end of the connecting block 28 via a fifth bolt 29, and the end of the rocker arm 26 away from the second bearing 27 is connected to the right end of the connecting block 28 via a sixth bolt 30. Since the transmission case, connecting block, and rocker arm are separable structures, from a production perspective, there is no process sequence issue in assembling the crankcase, transmission case, and rocker arm. The crankcase, transmission case, and rocker arm can be assembled separately and then quickly put together, reducing the final assembly process and improving production efficiency. From a maintenance perspective, if the second bearing 27 is damaged or the oil seal leaks, the rocker arm can be directly removed and replaced, reducing maintenance procedures.

[0048] For example, such as Figure 3 and Figure 4 As shown, the second bearing 27 is press-fitted onto the right side of the crankcase 2. An oil seal 49 is provided on the outer side cover of the second bearing 27. The oil seal 49 is fixedly connected to the crankcase 2. A second bushing 31, coaxially aligned with the center of the crankshaft 9 of the crankcase 2, is fitted into the inner hole of the oil seal 49. The inner end of the second bushing 31 presses against the second bearing 27. A screw 32 and a third nut 33 are provided on the rocker arm 26. The unthreaded portion of the screw 32 passes sequentially through the inner ring of the second bushing 31 and... In the inner ring of the second bearing 27, the threaded portion of the screw 32 passes through the rocker arm 26 and is threadedly connected to the third nut 33. The outer diameter of the unthreaded portion of the screw 32 is smaller than the outer diameter of the threaded portion, forming a shoulder 48. The shoulder 48 is pressed against the outer end of the second bushing 31. The clamping force of the screw 32 on the second bushing 31 is adjusted by rotating the third nut 33, thereby ensuring that the axial force on the second bearing 27 and the second bushing 31 is always the required preload. In this embodiment, the second bearing 27 is preferably a tapered roller bearing. After clamping it, the bearing is free from axial movement, thereby reducing the possible misalignment of the rear wheel due to axial movement and improving driving stability.

[0049] It should also be noted that the mounting structure of the first bearing 8 and the mounting structure of the second bearing 27 enable the entire rotating part to be axially limited on both the left and right sides of the crankcase 2, thereby restricting the axial movement of the entire rotating part and further preventing loosening.

[0050] For example, such as Figure 3As shown, the right end of the connecting block 28 is fixedly connected to the rear swingarm 35 by the seventh bolt 34. The rear swingarm 35 is connected to the axle 37 of the wheel 36. The output shaft 38 of the transmission box 3 passes through the axle 37 of the wheel 36 and the rear swingarm 35 in sequence, and is threaded with the fourth nut 39 at its end. Thus, the output shaft 38 of the transmission box 3 connects the wheel 36 and the rear swingarm 35 together, and through the cooperation with the fourth nut 39, the wheel 36 and the rear swingarm 35 are tightly fitted to form a stable connection structure. Furthermore, since both the output shaft 38 of the transmission box 3 and the rear swingarm 35 can rotate around the crankshaft 9 of the crankcase 2, the wheel 36 can also rotate around the crankshaft 9 of the crankcase 2.

[0051] For example, such as Figure 1 and Figure 6 As shown, there are two rear shock absorbers 4, symmetrically arranged on the left and right sides of the vehicle. The upper end of the rear shock absorber 4 is connected to the frame 1 via an eighth bolt 40 and a fifth nut 41. Since the diameter of the through hole on the frame 1 is larger than the diameter of the bolt 40, the rear shock absorber 4 can rotate around the eighth bolt 40. The lower end of the rear shock absorber 4 on the left side is rotatably connected to the rear suspension 10 via a ninth bolt 42, and the lower end of the rear shock absorber 4 on the right side is rotatably connected to the rear swingarm 35 via a tenth bolt 43. Thus, when the wheel 36 is subjected to bumps, the transmission case 3 and the wheel 36 can rotate around the crankshaft 9 of the crankcase 2, and the rear shock absorber 4 is compressed and rotated around the eighth bolt 40 to meet the change in the angular position of the rear suspension 10.

[0052] In the description of this invention, it should be understood that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" used in this invention should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0053] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A motorcycle engine mounting structure, characterized in that: The system includes a frame, crankcase, transmission case, and rear shock absorber. The crankcase is fixedly equipped with an upper suspension mount, a lower suspension mount, and a cylinder head suspension mount, all of which are connected to the frame. The transmission case is rotatably mounted on the crankcase via a first bearing, about the crankshaft center. A rear suspension mount is fixedly mounted at the rear end of the transmission case, connecting to the lower end of the rear shock absorber, while the upper end of the rear shock absorber is connected to the frame. A first bushing, coaxially aligned with the crankshaft center, is fixedly connected to the left side of the crankcase via bolts. The first bearing is press-fitted into the transmission case, with its inner ring engaging with the outer ring of the first bushing. The crankshaft of the crankcase passes through the transmission case in sequence. The inner ring of the first bushing extends into the transmission housing; a retaining ring is provided inside the transmission housing, the retaining ring abuts against the end face of the outer ring of the first bearing away from the crankcase; a retaining ring groove is provided inside the transmission housing for the retaining ring to be installed; a clamping nut is threadedly connected to the end of the first bushing away from the crankcase, the clamping nut abuts against the end face of the inner ring of the first bearing away from the crankcase; a rocker arm is provided on the right side of the crankcase, the rocker arm is rotatably mounted on the crankcase around the crankshaft center of the crankcase via a second bearing; a connecting block is provided between the transmission housing and the rocker arm, the transmission housing is connected to the left end of the connecting block via a fifth bolt, and the end of the rocker arm away from the second bearing is connected to the right end of the connecting block via a sixth bolt.

2. The motorcycle engine mounting structure as described in claim 1, characterized in that: The crankcase suspension assembly, consisting of the upper suspension, the lower suspension, and the cylinder head suspension, is provided in two sets, with the two sets of crankcase suspension assemblies arranged on the left and right sides of the crankcase.

3. The motorcycle engine mounting structure as described in claim 2, characterized in that: The upper suspension, lower suspension, and cylinder head suspension are all fitted with rubber buffer bushings with an interference fit. The suspension on the box body is connected to the vehicle frame by a first support bushing, a first bolt, and a first nut; wherein, the first support bushing is disposed between the suspension on the left and right sides of the box body, and the left and right ends of the first support bushing abut against the rubber buffer bushings on the suspension on the two sides of the box body respectively; the first bolt passes through the first support bushing and the rubber buffer bushings on the suspension on the box body; The cylinder head hanger is connected to the vehicle frame via a second support bushing, a second bolt, and a second nut; wherein, the second support bushing is disposed between the left and right cylinder head hangers, and the left and right ends of the second support bushing abut against the rubber buffer bushings on the cylinder head hangers on both sides; the second bolt passes through the second support bushing and the rubber buffer bushings on the cylinder head hanger; The lower suspension of the crankcase is connected to the vehicle frame via a rocker arm, a third bolt, and a fourth bolt. The rocker arm is located on the lower side of the crankcase and has a first connecting portion and a second connecting portion. The first connecting portion is positioned between the left and right lower suspensions of the crankcase, with its left and right ends respectively abutting against rubber buffer bushings on the lower suspensions of the crankcases on both sides. The third bolt passes through the rubber buffer bushings on the lower suspension and connects to the first connecting portion, which has a first threaded hole for threaded connection with the third bolt. The fourth bolt passes through the vehicle frame and connects to the second connecting portion, which has a second threaded hole for threaded connection with the fourth bolt.

4. The motorcycle engine mounting structure as described in claim 1, characterized in that: The inner diameter of the first bushing is larger than the outer diameter of the crankshaft of the crankcase, and a dynamic sealing structure is provided between the first bushing and the crankshaft of the crankcase.

5. The motorcycle engine mounting structure as described in claim 1, characterized in that: A mounting plate is fixedly provided at one end of the first bushing near the crankcase. The mounting plate has mounting holes for the fastening bolts to connect. A sealing ring is provided between the contact surface of the mounting plate and the crankcase.

6. The motorcycle engine mounting structure as described in claim 1, characterized in that: The transmission housing is equipped with a continuously variable transmission (CVT) drive wheel, which is mounted on the crankshaft of the crankcase. A crankshaft sleeve is fitted onto the crankshaft of the crankcase, and the outer diameter of the crankshaft sleeve is smaller than the inner diameter of the first sleeve. The end face of the CVT drive wheel near the crankcase abuts against the end face of the crankshaft sleeve.

7. The motorcycle engine mounting structure as described in claim 1, characterized in that: The second bearing is interference-fitted to the right side of the crankcase. An oil seal is provided on the outer cover of the second bearing. The oil seal is fixedly connected to the crankcase. A second bushing, coaxially arranged with the crankshaft center of the crankcase, is fitted inside the oil seal. The inner end of the second bushing is pressed against the second bearing. A screw and a third nut are provided on the rocker arm. The unthreaded portion of the screw is inserted into the inner ring of the second bushing and the inner ring of the second bearing in sequence. The threaded portion of the screw passes through the rocker arm and is threadedly connected to the third nut. The outer diameter of the unthreaded portion of the screw is smaller than the outer diameter of the threaded portion of the screw, forming a shoulder. The shoulder is pressed against the outer end of the second bushing.

8. The motorcycle engine mounting structure as described in claim 1, characterized in that: The right end of the connecting block is fixedly connected to a rear horizontal fork by a seventh bolt. The rear horizontal fork is connected to the wheel axle. The output shaft of the transmission box passes through the wheel axle and the rear horizontal fork in sequence, and is threaded to a fourth nut at its end.

9. The motorcycle engine mounting structure as described in claim 8, characterized in that: The rear shock absorber is provided in two parts and is symmetrically arranged on the left and right sides of the vehicle. The upper end of the rear shock absorber is connected to the frame by the eighth bolt and the fifth nut. The lower end of the rear shock absorber on the left side is connected to the rear suspension by the ninth bolt, and the lower end of the rear shock absorber on the right side is connected to the rear swingarm by the tenth bolt.

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