Gear shifting structure of engine

Abstract

The utility model discloses an engine gear shifting structure, which belongs to the technical field of engine gear shifting and comprises a gear shifting shaft, a first gear shifting assembly is arranged on the gear shifting shaft and comprises a shaft sleeve connected to the gear shifting shaft in a sliding mode, and limiting portions are arranged at the two ends of the shaft sleeve respectively. A first shifting fork and a first shifting fork head are independently connected to the shaft sleeve in a sliding mode, an elastic piece is arranged on the side, away from the first shifting fork, of the first shifting fork head, and the two ends of the elastic piece abut against the first shifting fork head and the limiting part respectively. A first shifting fork head and a first shifting fork on the first gear shifting assembly are independent of each other, when gear shifting operation starts, the first shifting fork head can act in advance under the action of a gear shifting drum and starts to compress an elastic piece, the first shifting fork delays to act, a shaft sleeve is pushed by the compressed elastic piece to move along a gear shifting shaft, and therefore the gear shifting operation is completed. And finally, gear shifting operation is realized. And the gear shifting convenience and the driving experience of a user are greatly improved.

Description

Technical Field

[0001] This utility model relates to an engine structure, and more specifically, to an engine shifting structure. Background Technology

[0002] Vehicle engines typically have a gear shift mechanism to enable gear changes and improve vehicle handling. However, most gear shift mechanisms are inconvenient during shifting. The gear drum usually needs to be in motion within the gear assembly of the engine to rotate; otherwise, it will be jammed and unable to turn. This results in a poor user experience. Furthermore, the gear shift mechanism inside the engine is more complex, more difficult to assemble, and has higher technical costs.

[0003] For example, Chinese Patent Publication No. CN208935286U, published on June 4, 2019, is a utility model entitled "A Motorcycle Engine Transmission," comprising a main shaft assembly, a countershaft assembly, a shift drum, and a shift fork assembly. The main shaft assembly meshes with the countershaft assembly, and the shift fork assembly connects the shift drum, the main shaft assembly, and the countershaft assembly. The main shaft assembly includes a drive shaft and a drive gear set mounted on the drive shaft, comprising a first-speed drive gear, a second-speed drive gear, a third-speed drive gear, a fourth-speed drive gear, a fifth-speed drive gear, and a sixth-speed drive gear. The countershaft assembly includes a countershaft and a driven gear set mounted on the countershaft; the driven gear set includes a first-speed driven gear, a second-speed driven gear, a third-speed driven gear, a fourth-speed driven gear, a fifth-speed driven gear, and a sixth-speed driven gear. This design provides smooth gear shifting in the motorcycle engine transmission, effectively reducing fuel consumption and improving energy transmission efficiency. However, in this scheme, the gear shift drum and the shift fork assembly are rigidly connected. The gear shift drum needs to apply force to the shift fork assembly first, and then the shift pawl and gear assembly can be engaged before the shift can be rotated and shifted. Therefore, the shifting operation is not convenient. Utility Model Content

[0004] This invention overcomes the problem of inconvenient engine gear shifting operation in existing systems and provides an engine gear shifting structure. This solution has a simple structure and can improve the operating experience of engine gear shifting, making gear shifting operation more convenient.

[0005] To solve the above-mentioned technical problems, this utility model adopts the following technical solution: an engine shifting structure, including a shifting shaft, a first shifting assembly on the shifting shaft, the first shifting assembly including a bushing slidably connected to the shifting shaft, limiting portions at both ends of the bushing, a first shift fork and a first shift fork head independently slidably connected to the bushing, an elastic element on the side of the first shift fork head away from the first shift fork, the two ends of the elastic element respectively abutting against the first shift fork head and the limiting portion. The first shift fork head and the first shift fork on the first shifting assembly have independent characteristics. When the shifting operation begins, the first shift fork head can move in advance under the action of the shifting drum and begin to compress the elastic element. During the start-up process, the transmission wheel set in the engine begins to rotate. When it rotates to the appropriate position, the first shift fork can start to move, and through the compressed elastic element, it pushes the bushing to move along the shifting shaft, thereby driving the first shift fork to move, realizing the shifting operation; greatly improving the convenience of shifting and the user's driving experience.

[0006] Preferably, the first shift fork head has a first protrusion on its radially outer side, and the first shift fork has a second protrusion on its radially outer side. Both the first and second protrusions have corresponding connecting holes, and guide members are provided within the connecting holes. The first protrusion on the first shift fork head and the second protrusion on the first shift fork are designed with connecting holes to achieve a circumferentially limiting connection between the first shift fork head and the first shift fork, preventing relative rotation between them.

[0007] Preferably, the guide member is fixedly connected to the first protrusion or the second protrusion; the length of the guide member is greater than the maximum sliding stroke of the first shift fork head. The guide member needs to be fixed together with the first protrusion or the second protrusion so that the guide member can also move axially along the shift shaft to a certain extent, but without affecting the independence of the first shift fork head and the first shift fork. At the same time, the guide member is designed to be longer to ensure that the guide member will not disengage from the connecting hole of the first protrusion and the second protrusion, thereby ensuring that the relative circumferential position of the first shift fork head and the first shift fork is fixed.

[0008] Preferably, the first shift fork head has a connecting portion on the side away from the shift fork, and the radial dimension of the connecting portion is smaller than the outer diameter of the first shift fork head. The elastic element engages with the connecting portion. The connecting portion can engage with the elastic element to ensure a secure connection at one end of the elastic element and prevent the elastic element from moving along the shift shaft on its own.

[0009] Preferably, the assembly also includes a shift drum and a drive pulley set. The shift drum has a first shift groove, and the first shift fork head engages with the first shift groove. The drive pulley set has a first shift pawl, and the first shift fork is inserted into the shaft portion of the first shift pawl. The shift drum can control the first shift assembly through the first shift groove, causing the first shift fork head to slide on the shift shaft. The first shift fork moves under the action of an elastic element or moves with the movement of the first shift fork head, thereby controlling the drive pulley set.

[0010] Preferably, the bushing has an annular groove at the end away from the first shift fork, and a limiting ring is provided on the annular groove. A limiting piece is provided between the limiting ring and the elastic element, and the limiting piece is slidably connected to the bushing. The end of the bushing away from the first shift fork is used to insert the first shift fork, the first shift fork head, and other structures into the bushing. Therefore, the limiting part at this location is a detachable structure. The annular groove is used to install the limiting ring, and the limiting piece and the elastic element are arranged below the limiting ring to abut against each other, ensuring the stability of the elastic element.

[0011] Preferably, a second shifting assembly is slidably connected to the shifting shaft. The second shifting assembly includes a second shift fork and a second shift fork head. The second shifting assembly can control the transmission wheels on the transmission wheel assembly, realizing the shifting operation of the transmission wheel assembly. Combined with the first shifting assembly, it can achieve control of more gears.

[0012] Preferably, the shift drum is further provided with a second shift groove, which cooperates with the second shift fork head. The second shift groove on the shift drum can cooperate with the second shift fork head to drive the second shift assembly to perform shifting operations.

[0013] Preferably, the transmission wheel assembly is provided with a second shift pawl, and the second shift fork is inserted into the shaft of the second shift pawl. The second shift pawl can engage with the gears in the transmission wheel assembly. When the second shift fork moves axially along the shift shaft, it can drive the second shift pawl to connect or disconnect from the gear assembly, thereby realizing the shifting operation.

[0014] Compared with the prior art, the beneficial effects of this utility model are: (1) During gear shifting, the shift fork head can move in advance and the shift fork moves in a delayed manner, which greatly improves the convenience of gear shifting and the user's driving experience; (2) The structural design is simple, which can simplify the assembly technology of the gear shifting structure and reduce technical costs; (3) The structure is stable, and the shift fork head and shift fork can maintain a relatively accurate position in the circumferential direction. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the gear shift shaft of this utility model.

[0016] Figure 2This is a cross-sectional view of the upper structure of the gear shift shaft of this utility model.

[0017] Figure 3 This is a cross-sectional view of the gear shift shaft of this utility model from another perspective.

[0018] Figure 4 This is a schematic diagram illustrating the application of the shifting structure of this utility model.

[0019] In the diagram: 1. Shift shaft, 2. First shift assembly, 3. Bushing, 4. Limiting part, 5. First shift fork, 6. First shift fork head, 7. Elastic element, 8. First protrusion, 9. Second protrusion, 10. Connecting hole, 11. Guide element, 12. Connecting part, 13. Shift drum, 14. Transmission wheel set, 15. First shift groove, 16. First pawl, 17. Limiting ring, 18. Limiting piece, 19. Second shift assembly, 20. Second shift fork, 21. Second shift fork head, 22. Second shift groove. Detailed Implementation

[0020] The technical solution of this utility model will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings.

[0021] Example 1: As Figures 1 to 3 The illustrated engine shifting structure includes a shift shaft 1, which is a cylindrical hollow shaft. A first shifting assembly 2 is disposed outside the shift shaft 1, and the first shifting assembly 2 can slide relative to the axial direction of the shift shaft 1. The first shifting assembly 2 includes a bushing 3, a first shift fork 5, a first shift fork head 6, and an elastic element 7. The first shift fork 5 and the first shift fork head 6 are two independent structures, slidably connected to the bushing 3, which in turn is slidably connected to the shift shaft 1. The elastic element 7 is fitted outside the bushing 3 and exerts a compressive effect on the first shift fork head 6, thus keeping the elastic element 7 in a compressed state. During shifting operations, the first shift fork head 6 can move in advance, while the first shift fork 5 has a lag. During gear engagement or shifting, it is not necessary to align the gear set inside the engine with the shift pawl; gear engagement or shifting can be performed in advance. This greatly improves the convenience of engine shifting and the user's control over the vehicle, enhancing the driving experience.

[0022] Specifically, the shift shaft 1 is a smooth shaft, and the bushing 3 is sleeved on the outside of the shift shaft 1. Limiting parts 4 are provided at the upper and lower ends of the bushing 3. The limiting part 4 at the bottom of the bushing 3 is a step that protrudes radially from the surface of the bushing 3 (in this embodiment, it is defined as the first limiting part). The first limiting part and the bushing 3 are integrally formed. The limiting part 4 at the top of the bushing 3 is a detachable structure. Since the bushing 3 also needs to be equipped with the first shift fork 5 and the first shift fork head 6, in order to assemble the first shift fork 5 and the first shift fork head 6 into the bushing 3, a detachable structure is designed at the top of the bushing 3 as a limiting part 4 (in this embodiment, it is defined as the second limiting part). The second limiting part and the first limiting part can limit the first shift fork 5, the first shift fork head 6 and the elastic element 7, preventing the first shift fork 5, the first shift fork head 6 and the elastic element 7 from detaching from the bushing 3. Meanwhile, the first limiting part is arranged at the bottom of the bushing 3 and designed as an integral structure, which is conducive to the first limiting part bearing the weight of the first shift fork 5 and the first shift fork head 6, making the structural design more reasonable.

[0023] The first shift fork 5 is located below the first shift fork head 6. One end of the first shift fork 5 is a sleeve structure that slides through the shift shaft 1, and the other end is a fork structure that can cooperate with the shift pawl. One end of the first shift fork head 6 is a sleeve structure that slides through the shift shaft 1, and the other end is a protruding structure that can cooperate with the shift drum.

[0024] An elastic element 7 is provided between the first shift fork head 6 and the second limiting part. In this embodiment, the elastic element 7 is a circular spring structure. The bottom end of the elastic element 7 abuts against the top of the first shift fork head 6, and the other end of the elastic element 7 abuts against the lower surface of the second limiting part. The elastic element 7 is always kept in a compressed state. Specifically, a connecting part 12 is provided at the top of the first shift fork head 6. The connecting part 12 is a hollow shaft structure. The radial dimension of the connecting part 12 is smaller than the radial dimension of the main body of the first shift fork head 6 and is adapted to the inner diameter of the elastic element 7. Thus, the bottom of the elastic element 7 can be engaged with the connecting part 12 of the first shift fork head 6, thereby ensuring the connection stability of the elastic element 7.

[0025] Furthermore, the second limiting part is a detachable structure, including a limiting ring 17, a limiting piece 18, and an annular groove disposed above the bushing 3. Specifically, the annular groove is an annular groove structure near the upper surface of the bushing 3, while the limiting ring 17 has a C-shaped structure. The inner diameter of the limiting ring 17 matches the outer diameter of the annular groove, and the outer diameter of the limiting ring 17 is larger than the outer diameter of the bushing 3, thus the limiting ring 17 can form a limiting structure on the circumferential surface of the bushing 3. The limiting piece 18 is arranged below the limiting ring 17, with the top of the elastic member 7 abutting against the bottom of the limiting piece 18. Since the elastic member 7 is in a compressed state, the limiting piece 18 is pressed tightly against the lower surface of the limiting ring 17 by the elastic member 7, thus forming the second limiting part.

[0026] It should also be noted that a first protrusion 8 is provided on the radial circumferential surface of the first shift fork head 6, and a second protrusion 9 is provided on the radial circumferential surface of the first shift fork 5. The first protrusion 8 and the second protrusion 9 are aligned in the vertical direction, and connecting holes 10 are provided on the first protrusion 8 and the second protrusion 9. The connecting holes 10 in the first protrusion 8 and the second protrusion 9 are also aligned in the vertical direction. The connecting holes 10 of the first protrusion 8 and the second protrusion 9 are connected by a guide member 11; in this embodiment, the guide member 11 is a cylindrical connecting shaft structure. Furthermore, the guide member 11 is fixed together with the connecting hole 10 in the first protrusion 8, so that when the first shift fork head 6 moves axially along the shift shaft 1, the guide member 11 can also move in the vertical direction. Furthermore, the axial length of the guide member 11 within the second protrusion 9 needs to be greater than the maximum sliding stroke of the first shift fork head 6 on the shift shaft 1. This ensures that when the first shift fork head 6 reaches its upper limit position, the lower end of the guide member 11 remains engaged with the connecting hole 10 within the second protrusion 9, preventing the guide member 11 from disengaging from the connecting hole 10 within the second protrusion 9. This prevents relative rotation between the first shift fork head 6 and the first shift fork 5 during gear shifting. It should also be noted that the guide member 11 can also be fixedly connected to the connecting hole 10 within the second protrusion 9. Similarly, in this case, the axial length of the guide member 11 within the connecting hole 10 within the first protrusion 8 needs to be greater than the maximum sliding stroke of the first shift fork head 6 on the shift shaft 1. This ensures that when the first shift fork head 6 reaches its upper limit position, the upper end of the guide member 11 remains engaged with the connecting hole 10 within the first protrusion 8.

[0027] The specific working principle of this scheme is as follows: When the shift drum performs a shift operation (which requires the first shift fork 5 to engage the shift pawl and connect with the transmission wheel set), the shift drum is first rotated, causing the first shift fork head 6 to move upward along the axial direction of the bushing 3. At this time, since the shift pawl has not yet engaged with the transmission wheel set, the first shift fork 5 is in a stationary state and abuts against the first limiting part below the bushing 3. Thus, the bushing 3 as a whole remains unchanged relative to the shift shaft 1, and only the first shift fork head 6 moves upward to compress the elastic element 7. When the input shaft drives the transmission wheel set to rotate to the appropriate position, the shift pawl and the connecting hole groove on the transmission wheel set are aligned. At this time, the compressive force of the elastic element 7 is greater than the overall weight of the bushing 3 and the first shift fork 5, pulling the bushing 3 and the first shift fork 5 upward along the axial direction of the shift shaft 1, thereby enabling the shift pawl and the hole groove on the transmission wheel set to engage, which realizes the shift operation. Therefore, in this solution, since the first shift fork head 6 and the first shift fork 5 are independent structures, the shift drum can be rotated in advance, so that the first shift fork head 6 moves earlier, while the first shift fork 5 moves later, which greatly improves the immediacy of the user's shifting operation and improves the driving experience.

[0028] Example 2: Figures 1 to 4 The illustrated engine shifting structure includes a shift shaft 1, which is a cylindrical hollow shaft. A first shifting assembly 2 is disposed outside the shift shaft 1, and the first shifting assembly 2 can slide relative to the axial direction of the shift shaft 1. The first shifting assembly 2 includes a bushing 3, a first shift fork 5, a first shift fork head 6, and an elastic element 7. The first shift fork 5 and the first shift fork head 6 are two independent structures, slidably connected to the bushing 3, which in turn is slidably connected to the shift shaft 1. The elastic element 7 is fitted outside the bushing 3 and exerts a compressive effect on the first shift fork head 6, thus keeping the elastic element 7 in a compressed state. During shifting operations, the first shift fork head 6 can move in advance, while the first shift fork 5 has a lag. During gear engagement or shifting, it is not necessary to align the gear set inside the engine with the shift pawl; gear engagement or shifting can be performed in advance. This greatly improves the convenience of engine shifting and the user's control over the vehicle, enhancing the driving experience.

[0029] Specifically, the shift shaft 1 is a smooth shaft, and the bushing 3 is sleeved on the outside of the shift shaft 1. Limiting parts 4 are provided at the upper and lower ends of the bushing 3. The limiting part 4 at the bottom of the bushing 3 is a step that protrudes radially from the surface of the bushing 3 (in this embodiment, it is defined as the first limiting part). The first limiting part and the bushing 3 are integrally formed. The limiting part 4 at the top of the bushing 3 is a detachable structure. Since the bushing 3 also needs to be equipped with the first shift fork 5 and the first shift fork head 6, in order to assemble the first shift fork 5 and the first shift fork head 6 into the bushing 3, a detachable structure is designed at the top of the bushing 3 as a limiting part 4 (in this embodiment, it is defined as the second limiting part). The second limiting part and the first limiting part can limit the first shift fork 5, the first shift fork head 6 and the elastic element 7, preventing the first shift fork 5, the first shift fork head 6 and the elastic element 7 from detaching from the bushing 3. Meanwhile, the first limiting part is arranged at the bottom of the bushing 3 and designed as an integral structure, which is conducive to the first limiting part bearing the weight of the first shift fork 5 and the first shift fork head 6, making the structural design more reasonable.

[0030] The first shift fork 5 is located below the first shift fork head 6. One end of the first shift fork 5 is a sleeve structure that slides through the shift shaft 1, while the other end is a fork structure that engages with the first shift pawl 16. Specifically, the engine also contains a transmission wheel assembly 14, which has a shift wheel. The inner ring of the shift wheel has a slot for engaging with the shift pawl. When the shift pawl aligns with the slot, it enters the slot, causing it to rotate and shift gears. The fork of the first shift fork 5 is inserted into the shaft of the first shift pawl 16 (without affecting the circumferential rotation of the first shift pawl 16). The connection and disconnection between the first shift pawl 16 and the shift wheel are controlled by the axial movement of the first shift fork 5 along the shift shaft 1. One end of the first shift fork head 6 is a sleeve structure that slides through the shift shaft 1, while the other end is a protruding structure that can cooperate with the shift drum 13. Specifically, the shift drum 13 is provided with a first shift groove 15, which is a curved groove structure. The first shift fork head 6 cooperates with the first shift groove 15. When the shift drum 13 rotates, the first shift fork head 6 moves with the shape of the first shift groove 15, thereby driving the first shift fork head 6 to move along the axial direction of the shift shaft 1.

[0031] An elastic element 7 is provided between the first shift fork head 6 and the second limiting part. In this embodiment, the elastic element 7 is a circular spring structure. The bottom end of the elastic element 7 abuts against the top of the first shift fork head 6, and the other end of the elastic element 7 abuts against the lower surface of the second limiting part. The elastic element 7 is always kept in a compressed state. Specifically, a connecting part 12 is provided at the top of the first shift fork head 6. The connecting part 12 is a hollow shaft structure. The radial dimension of the connecting part 12 is smaller than the radial dimension of the main body of the first shift fork head 6 and is adapted to the inner diameter of the elastic element 7. Thus, the bottom of the elastic element 7 can be engaged with the connecting part 12 of the first shift fork head 6, thereby ensuring the connection stability of the elastic element 7.

[0032] Furthermore, the second limiting part is a detachable structure, including a limiting ring 17, a limiting piece 18, and an annular groove disposed above the bushing 3. Specifically, the annular groove is an annular groove structure near the upper surface of the bushing 3, while the limiting ring 17 has a C-shaped structure. The inner diameter of the limiting ring 17 matches the outer diameter of the annular groove, and the outer diameter of the limiting ring 17 is larger than the outer diameter of the bushing 3, thus the limiting ring 17 can form a limiting structure on the circumferential surface of the bushing 3. The limiting piece 18 is arranged below the limiting ring 17, with the top of the elastic member 7 abutting against the bottom of the limiting piece 18. Since the elastic member 7 is in a compressed state, the limiting piece 18 is pressed tightly against the lower surface of the limiting ring 17 by the elastic member 7, thus forming the second limiting part.

[0033] It should also be noted that a first protrusion 8 is provided on the radial circumferential surface of the first shift fork head 6, and a second protrusion 9 is provided on the radial circumferential surface of the first shift fork 5. The first protrusion 8 and the second protrusion 9 are aligned in the vertical direction, and connecting holes 10 are provided on the first protrusion 8 and the second protrusion 9. The connecting holes 10 in the first protrusion 8 and the second protrusion 9 are also aligned in the vertical direction. The connecting holes 10 of the first protrusion 8 and the second protrusion 9 are connected by a guide member 11; in this embodiment, the guide member 11 is a cylindrical connecting shaft structure. Furthermore, the guide member 11 is fixed together with the connecting hole 10 in the first protrusion 8, so that when the first shift fork head 6 moves axially along the shift shaft 1, the guide member 11 can also move in the vertical direction. Furthermore, the axial length of the guide member 11 within the second protrusion 9 needs to be greater than the maximum sliding stroke of the first shift fork head 6 on the shift shaft 1. This ensures that when the first shift fork head 6 reaches its upper limit position, the lower end of the guide member 11 remains engaged with the connecting hole 10 within the second protrusion 9, preventing the guide member 11 from disengaging from the connecting hole 10 within the second protrusion 9. This prevents relative rotation between the first shift fork head 6 and the first shift fork 5 during gear shifting. It should also be noted that the guide member 11 can also be fixedly connected to the connecting hole 10 within the second protrusion 9. Similarly, in this case, the axial length of the guide member 11 within the connecting hole 10 within the first protrusion 8 needs to be greater than the maximum sliding stroke of the first shift fork head 6 on the shift shaft 1. This ensures that when the first shift fork head 6 reaches its upper limit position, the upper end of the guide member 11 remains engaged with the connecting hole 10 within the first protrusion 8.

[0034] In addition, a second shift assembly 19 is also provided on the shift shaft 1. The second shift assembly 19 is located above the first shift assembly 2. The second shift assembly 19 includes a second shift fork 20 and a second shift fork head 21. The structural design of the second shift assembly 19 can be the same as that of the first shift assembly 2, that is, the second shift fork 20 and the second shift fork head 21 are also independently designed; or the structural design of the second shift assembly 19 can be different from that of the first shift assembly 2, that is, the second shift fork 20 and the second shift fork head 21 are integrated into one unit. When the former design is adopted, the shifting operation can be made more convenient; when the latter design is adopted, the shifting operation is also more convenient than the transmission design.

[0035] The shift drum 13 is also provided with a second shift groove 22, which is a curved groove structure. The second shift fork head 21 of the second shift assembly 19 cooperates with the second shift groove 22. When the shift drum 13 rotates, the second shift fork head 21 moves axially on the shift shaft 1 according to the shape of the second shift groove 22. The transmission wheel set 14 is provided with a second pawl (not shown in the figure). The second shift fork 20 on the second shift assembly 19 is also inserted into the shaft position of the second pawl. Its working process is the same as that of the first shift fork 5 and the first pawl 16, and will not be described again here.

[0036] The specific working principle of this scheme is as follows (taking the design of the second shifting assembly 19 and the first shifting assembly 2 as the same as that of the first shifting assembly 2): When the shifting drum 13 performs a shifting operation (it is necessary for the first shift fork 5 to move the first shift pawl 16 and the transmission wheel set 14 to connect, and for the second shift fork 20 to move the second shift pawl and the transmission wheel set 14 to connect), firstly, the shifting drum 13 is rotated, so that the first shift fork head 6 moves upward along the axial direction of the bushing 3. At this time, since the first shift pawl 16 has not yet cooperated with the transmission wheel set 10, the first shift fork 5 is in a stationary state and is connected to the first shift pawl below the bushing 3. A limiting part abuts, so the overall position of the bushing 3 relative to the shift shaft 1 remains unchanged, only the first shift fork head 6 moves upward to compress the elastic element 7; when the input shaft drives the transmission wheel set 10 to rotate to the appropriate position, the connecting hole groove on the first shift pawl 16 and the transmission wheel set 14 aligns. At this time, the compressive force of the elastic element 7 is greater than the overall weight of the bushing 3 and the first shift fork 5, pulling the bushing 3 and the first shift fork 5 upward along the shift shaft 1 axis, so that the hole groove on the first shift pawl 16 and the transmission wheel set 14 are engaged, that is, the shifting operation is realized. The working process of the second shifting assembly 19 is the same as the working process of the first shifting assembly 2 and is carried out synchronously, which will not be described in detail here. Therefore, in this solution, since the first shift fork head 6 and the first shift fork 5 are independent structures, the shift drum can be rotated in advance, so that the first shift fork head 6 moves in advance, while the first shift fork 5 moves later; at the same time, multiple shifting assemblies can be set to realize shifting to more different gears, which greatly improves the immediacy of the user's shifting operation and improves the driving experience.

Claims

1. An engine shifting structure, characterized in that, The device includes a gear shift shaft, on which a first gear shift assembly is provided. The first gear shift assembly includes a bushing slidably connected to the gear shift shaft. Limiting portions are provided at both ends of the bushing. A first shift fork and a first shift fork head are independently slidably connected to the bushing. An elastic element is provided on the side of the first shift fork head away from the first shift fork. The two ends of the elastic element abut against the first shift fork head and the limiting portion, respectively.

2. The engine shifting structure according to claim 1, characterized in that, The first shift fork head has a first protrusion on its radially outer side and a second protrusion on its radially outer side. Both the first protrusion and the second protrusion have corresponding connecting holes, and a guide is provided in the connecting hole.

3. The engine shifting structure according to claim 2, characterized in that, The guide member is fixedly connected to the first protrusion or the second protrusion; the length of the guide member is greater than the maximum sliding stroke of the first shift fork head.

4. The engine shifting structure according to claim 1, characterized in that, The first shift fork head has a connecting part on the side away from the shift fork, the radial dimension of the connecting part is smaller than the outer diameter of the first shift fork head, and the elastic element is engaged with the connecting part.

5. An engine shifting structure according to any one of claims 1 to 4, characterized in that, It also includes a shift drum and a drive wheel assembly. The shift drum is provided with a first shift groove, and the first shift fork head cooperates with the first shift groove. The drive wheel assembly is provided with a first shift pawl, and the first shift fork is inserted into the shaft of the first shift pawl.

6. An engine shifting structure according to any one of claims 1 to 4, characterized in that, The bushing has an annular groove at one end away from the first shift fork. A limiting ring is provided on the annular groove. A limiting piece is provided between the limiting ring and the elastic element. The limiting piece is slidably connected to the bushing.

7. The engine shifting structure according to claim 5, characterized in that, A second shift assembly is also slidably connected to the shift shaft, the second shift assembly including a second shift fork and a second shift fork head.

8. The engine shifting structure according to claim 7, characterized in that, The shift drum is also provided with a second shift groove, which cooperates with the second shift fork head.

9. The engine shifting structure according to claim 7, characterized in that, The transmission wheel assembly is provided with a second pawl, and the second fork is inserted into the shaft of the second pawl.

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