Gear shifting structure, engine and tricycle

Abstract

The utility model provides a gear shifting structure. The gear shifting structure comprises a gear shifting disc; a first shift fork; a second shift fork; a first power shaft; a second power shaft; the gear shifting piece comprises a first sliding pawl and a second sliding pawl which are arranged on the first power shaft and the second power shaft in a sliding mode respectively. The gear shifting disc rotates forwards and backwards under the action of external force, so that the first sliding pawl is selectively meshed with the first neutral gear tooth or the second gear tooth, the second sliding pawl is selectively meshed with the third gear tooth, the second neutral gear tooth or the first gear tooth, and a first gear state, a second gear state or a third gear state is formed. The problem that in the prior art, an existing gear shifting structure is not flexible in gear shifting is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of engines, in particular to a gear shifting structure, an engine and a tricycle. Background Art

[0002] An engine is a machine that can convert other forms of energy into mechanical energy, including internal combustion engines (reciprocating piston engines), external combustion engines (Stirling engines, steam engines, etc.), jet engines, electric motors, etc. Three-wheeled motorcycle engines generally use internal combustion engines. At present, when a motorcycle is shifting gears during driving, it is usually done by using the force of the pawl and the pawl groove. However, when the engine speed is high, the coordination between the pawl and the pawl groove often results in uneven force, which can easily lead to problems such as difficulty in shifting gears, gear slipping, and inflexible shifting, resulting in a poor driving experience for the driver. Utility Model Content

[0003] In view of the deficiencies in the prior art, the utility model provides a gear shifting structure, which solves the problem of inflexible gear shifting of the prior art gear shifting structure.

[0004] According to an embodiment of the utility model, a shifting structure includes:

[0005] A shift plate having a first shift groove and a second shift groove;

[0006] A first shift fork, slidably disposed in the first shift groove;

[0007] A second shift fork is slidably disposed in the second shift groove, and the first shift fork and the second shift fork are connected via a shift fork shaft;

[0008] A first power shaft, coaxially sleeved with a power gear, a first shift gear and a second shift gear in sequence along its axial direction, a first neutral gear and a second gear gear spaced apart from each other, and the second gear gear is connected to the second shift gear;

[0009] The second power shaft is coaxially sleeved with a third shift gear, a first linkage gear and a second linkage gear in sequence along its axial direction, the third shift gear is meshed with the power gear, the first linkage gear and the second linkage gear are respectively meshed with the first shift gear and the second shift gear, and a third gear tooth, a second neutral gear tooth and a first gear tooth are sequentially arranged between the third shift gear and the first linkage gear, the third gear tooth is connected with the third shift gear, and the first gear tooth is at least partially hidden in the first linkage gear;

[0010] A shift member, comprising a first sliding pawl and a second sliding pawl respectively slidably disposed on the first power shaft and the second power shaft, wherein the first sliding pawl and the second sliding pawl are respectively connected to the first shift fork and the second shift fork, and both have internal teeth;

[0011] Wherein, the shift plate rotates forward and reversely under the action of external force, so as to respectively link the first sliding pawl and the second sliding pawl through the first shift fork and the second shift fork to slide back and forth between the first shift gear and the second shift gear and between the third shift gear and the first linkage gear;

[0012] In the axial direction of the first power shaft and the second power shaft, the first sliding pawl is selectively engaged with the first neutral gear tooth or the second gear tooth, and the second sliding pawl is selectively engaged with the third gear tooth, the second neutral gear tooth or the first gear tooth to form a first gear state, a second gear state or a third gear state;

[0013] In the first gear state, the first sliding pawl and the second sliding pawl are respectively engaged with the first neutral gear tooth and the first gear tooth;

[0014] In the second gear state, the first sliding pawl and the second sliding pawl are respectively engaged with the second gear tooth and the second neutral gear tooth;

[0015] In the third gear state, the first sliding pawl and the second sliding pawl are respectively engaged with the first neutral gear tooth and the third gear tooth.

[0016] Preferably, the first shift groove comprises a first inclined section, a connecting section and a second inclined section connected in sequence, one end of the first inclined section and one end of the second inclined section converge to opposite ends of the connecting section respectively, and the other ends of the two are inclined in opposite directions respectively.

[0017] Preferably, the first inclined section, the connecting section and the second inclined section are constructed in a V-shaped structure, and the open ends thereof are arranged toward the second shift groove.

[0018] Preferably, the connecting section is located at the closed end of the V-shaped structure, and the connecting section has a transition point perpendicular to the axial direction of the first power shaft.

[0019] Preferably, the second shift groove comprises a third inclined segment, a fourth inclined segment and a fifth inclined segment connected in sequence, the distal ends of the third inclined segment and the fourth inclined segment are inclined in different directions, and the distal ends of the fourth inclined segment and the fifth inclined segment are inclined in different directions.

[0020] Preferably, a gap is formed between the third inclined segment, the fourth inclined segment and the fifth inclined segment, and the gap is arranged toward the first shift groove.

[0021] Preferably, the fifth inclined section is provided with a corner point bent toward the notch.

[0022] Preferably, the shifting structure also includes a driving member for driving the shift plate to rotate forward and reverse, the driving member includes a meshing pawl and a ratchet gear, and a driving shaft for connecting the ratchet gear and the shift plate, the ratchet gear has three ratchet grooves, so that when the pawl is driven to rotate by an external force, the ratchet gear is linked to rotate, and respectively correspond to the first gear state, the second gear state and the third gear state.

[0023] The utility model also provides an engine, comprising the above-mentioned gear shifting structure.

[0024] The utility model also provides a tricycle, comprising the engine described above.

[0025] Compared with the prior art, the utility model has the following beneficial effects: the first shift groove and the second shift groove are respectively slidably provided with the first shift fork and the second shift fork, and the first shift fork and the second shift fork are used to respectively link the first sliding pawl and the second sliding pawl to slide back and forth axially on the first power shaft and the second power shaft, thereby reducing the movement stroke of the first sliding pawl and the second sliding pawl during gear shifting; at the same time, the meshing method between the gears is simple and convenient, thereby reducing the transmission error of multiple gears meshing with each other, and avoiding the gear shifting structure from having difficulty in shifting gears, disengaging gears, and inflexible gear shifting. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the shifting structure of the utility model;

[0027] Figure 2 This is another azimuth structural diagram of the shift structure of the utility model;

[0028] Figure 3 for Figure 2 A partial enlarged view of the middle A;

[0029] Figure 4 is a schematic diagram of the structure of the first power shaft and the second power shaft;

[0030] Figure 5 It is a structural schematic diagram of the shift plate in the utility model;

[0031] Figure 6 It is a partial structural schematic diagram of the driving component in the utility model.

[0032] Description of Figure Numbers:

[0033] 1. Shift plate; 101. Shift fork shaft; 2. First shift groove; 201. First inclined section; 202. Connecting section; 203. Second inclined section; 3. Second shift groove; 301. Third inclined section; 302. Fourth inclined section; 303. Fifth inclined section; 304. Notch; 305. Corner point; 4. First shift fork; 5. Second shift fork; 6. First power shaft; 601. First shift gear; 602. Second shift gear; 603. First Neutral gear; 604, second gear gear; 605, power gear; 7, second power shaft; 701, third shift gear; 702, first linkage gear; 703, second linkage gear; 703, second neutral gear; 704, first gear gear; 705, third gear gear; 8, first sliding pawl; 801, inner teeth; 9, second sliding pawl; 10, pawl; 11, ratchet gear; 12, first drive gear; 13, second drive gear; 14, engine.

[0034] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and beneficial effects of the utility model more clear, the technical solution of the utility model is further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0036] See also Figures 1 to 6 The utility model provides a shifting structure, comprising:

[0037] A shift plate 1 is provided with a first shift groove 2 and a second shift groove 3;

[0038] A first shift fork 4, slidably disposed in the first shift groove 2;

[0039] A second shift fork 5 is slidably disposed in the second shift groove 3, and the first shift fork 4 and the second shift fork 5 are connected via a shift fork shaft 101;

[0040] The first power shaft 6 is coaxially sleeved with a power gear 605, a first shift gear 601 and a second shift gear 602 in sequence along its axial direction, a first neutral gear 603 and a second gear gear 604 are arranged between the first shift gear 601 and the second shift gear 602, and the second gear gear 604 is connected to the second shift gear 602;

[0041] The second power shaft 7 is coaxially sleeved with a third shift gear 701, a first linkage gear 702 and a second linkage gear 703 in sequence along its axial direction, the third shift gear 701 is meshed with the power gear 605, the first linkage gear 702 and the second linkage gear 703 are respectively meshed with the first shift gear 601 and the second shift gear 602, and a third gear tooth 705, a second neutral gear tooth 703 and a first gear tooth 704 are sequentially arranged between the third shift gear 701 and the first linkage gear 702, the third gear tooth 705 is connected with the third shift gear 701, and the first gear tooth 704 is at least partially hidden in the first linkage gear 702;

[0042] A shifting member, comprising a first sliding pawl 8 and a second sliding pawl 9 respectively slidably disposed on the first power shaft 6 and the second power shaft 7, wherein the first sliding pawl 8 and the second sliding pawl 9 are respectively connected to the first shift fork 4 and the second shift fork 5, and both have internal teeth 801;

[0043] The shift plate 1 rotates forward and reversely under the action of an external force, so as to respectively link the first sliding pawl 8 and the second sliding pawl 9 to slide back and forth between the first shift gear 601 and the second shift gear 602 and between the third shift gear 701 and the first linkage gear 702 through the first shift fork 4 and the second shift fork 5;

[0044] In the axial direction of the first power shaft 6 and the second power shaft 7, the first sliding pawl 8 is selectively engaged with the first neutral gear tooth 603 or the second gear tooth 604, and the second sliding pawl 9 is selectively engaged with the third gear tooth 705, the second neutral gear tooth 703 or the first gear tooth 704, so as to form a first gear state, a second gear state or a third gear state;

[0045] In the first gear state, the first sliding pawl 8 and the second sliding pawl 9 are respectively engaged with the first neutral gear tooth 603 and the first gear tooth 704;

[0046] In the second gear state, the first sliding pawl 8 and the second sliding pawl 9 are respectively engaged with the second gear tooth 604 and the second neutral gear tooth 703;

[0047] In the third gear state, the first sliding pawl 8 and the second sliding pawl 9 are respectively engaged with the first neutral gear tooth 603 and the third gear tooth 705 .

[0048] In this embodiment, the shift structure is arranged in the housing of the engine 14, and the shift structure includes a first shift groove 2 and a second shift groove 3 arranged on the shift plate 1, and a first shift fork 4 and a second shift fork 5 are slidably arranged in the first shift groove 2 and the second shift groove 3 respectively, and the first shift fork 4 and the second shift fork 5 are connected by a shift fork shaft 101 to achieve synchronous movement, and the first shift fork 4 and the second shift fork 5 are used to drive the shift member to connect with the first power shaft 6 and the second power shaft 7, and the shift member includes a first sliding pawl 8 and a second sliding pawl 9 respectively slidably arranged on the first power shaft 6 and the second power shaft 7, and a power gear 605, a first shift gear 601 and a second shift gear 602 are sequentially sleeved on the first power shaft 6, A first neutral gear 603 and a second gear gear 604 are sequentially arranged between the first shift gear 601 and the second shift gear 602, and the second gear gear 604 is connected to the second shift gear 602. The power gear 605 is used to receive power to rotate the first power shaft 6. The first sliding pawl 8 can slide back and forth between the first neutral gear 603 and the second gear gear 604 to achieve the switching of the engine 14 between the second gear and the neutral gear. The third shift gear 701, the first linkage gear 702 and the second linkage gear 703 are sequentially sleeved on the second power shaft 7. The third shift gear 701 is meshed with the power gear 605, and the first linkage gear 702 and the second linkage gear 703 are respectively meshed with the first shift gear 601. The third gear teeth 705, the second neutral gear teeth 703 and the first gear teeth 704 are arranged in sequence between the third gear gear 701 and the first linkage gear 702. The third gear teeth 705 are connected to the third gear gear 701, and the first gear teeth 704 are partially hidden in the first linkage gear 702. The second sliding ratchet 9 slides back and forth between the third gear teeth 705, the second neutral gear teeth 703 and the first gear teeth 704 to realize the switching of the engine 14 between the first gear, the neutral gear and the third gear. The shift plate 1 (the shift arm arranged outside the housing of the engine 14) rotates forward and reversely under the action of external force, so that the first sliding ratchet 8 and the second sliding ratchet 9 slide synchronously on the first power shaft 6 and the second power shaft 7. The movable pawl 8 can selectively slide on the first neutral gear tooth 603 and mesh with the second gear tooth 604, and the second sliding pawl 9 can selectively mesh with the third gear tooth 705, the second neutral gear tooth 703 or the first gear tooth 704 to cooperate to form a first gear state, a second gear state or a third gear state; when the first sliding pawl 8 is meshed with the first neutral gear 603 on the first power shaft 6, and the second sliding pawl 9 is meshed with the first gear tooth 704 on the second power shaft 7, the second shift gear 602, the second linkage gear 703 and the third shift gear 701 are in an idling state, and the first shift gear 601 receives the power transmission from the power gear 605 and transmits the power to the first linkage gear 702 so that the engine 14 is in the first gear state;When the first sliding pawl 8 slides and meshes with the second gear tooth 604 on the first power shaft 6, the second sliding pawl 9 slides and meshes with the second neutral gear tooth 703 on the second power shaft 7, the first shift gear 601, the first linkage gear 702 and the third shift gear 701 are in an idling state, the second shift gear 602 receives the power from the power gear 605 and links the second linkage gear 703 to transmit the power, so that the engine 14 is in the second gear state; when the first sliding pawl 8 slides and meshes with the first neutral gear 603 on the first power shaft 6, the second sliding pawl 9 slides and meshes with the third gear tooth 703 on the second power shaft 7 5, at this time, the second shift gear 602, the first shift gear 601, the first linkage gear 702 and the second linkage gear 703 are in an idling state, and the third shift gear 701 directly transmits power through the power gear 605, so that the engine 14 is in the third gear state; through the forward and reverse rotation of the shift plate 1, the first shift fork 4 and the second shift fork 5 are respectively linked to the first sliding pawl 8 and the second sliding pawl 9 to slide back and forth between the first power shaft 6 and the second power shaft 7, and the two are between the first shift gear 601 and the second shift gear 602 and between the third shift gear 701 and the first linkage gear 702 The reciprocating sliding replaces the traditional shifting mode, so that the linkage and mobility of the first sliding pawl 8 and the second sliding pawl 9 are smoother and the force is evenly applied during the shifting, so as to avoid the problems of difficulty in shifting, shifting out and inflexible shifting. At the same time, a plurality of inner teeth 801 are arranged in a circumferential array on the inner wall of the first sliding pawl 8 and the second sliding pawl 9, and the inner teeth 801 are used to mesh with the first neutral gear teeth 603, the first gear teeth 704, the second gear teeth 604, the second neutral gear teeth 703 and the third gear teeth 705. The first neutral gear teeth 603, the first gear teeth 704, the second gear teeth 604, the second neutral gear teeth 703 and the third gear teeth 705 are formed at The splines of the first power shaft 6 and the second power shaft 7, each inner tooth 801 is staggered with each spline, so that the first sliding pawl 8 and the second sliding pawl 9 play a circumferential positioning when sliding on the first power shaft 6 and the second power shaft 7, avoiding the situation of disengagement, and the inner tooth 801 has two symmetrically arranged inclined surfaces, which are used to contact the two ends of the spline respectively, so as to guide the sliding direction of the first sliding pawl 8 and the second sliding pawl 9, so that it can smoothly mesh with one of the first neutral gear tooth 603, the first gear tooth 704, the second gear tooth 604, the second neutral gear tooth 703, and the third gear tooth 705, thereby improving the smoothness of gear shifting. ;

[0049] The first shift groove 2 includes a first inclined section 201, a connecting section 202 and a second inclined section 203 which are connected in sequence. One end of the first inclined section 201 and one end of the second inclined section 203 converge to opposite ends of the connecting section 202, and the other ends of the two are inclined in opposite directions.

[0050] In this embodiment, the first shift groove 2 includes a first inclined section 201, a connecting section 202 and a second inclined section 203 connected in sequence. The first inclined section 201 and the second inclined section 203 are respectively located at the two ends of the connecting section 202, and are inclined in opposite directions. This symmetrical but opposite direction design helps the first shift fork 4 to slide quickly and accurately in the first shift groove 2 during gear shifting, so that the force transmission during the gear shifting process is smoother. The shifting method of the first shift fork 4 in the first shift groove 2 is linked by the forward and reverse rotation of the shift plate 1, which replaces the shifting method in the prior art where the force is directly applied to the pawl and the pawl groove, so as to adapt to different gear requirements, optimize the shifting feel, reduce resistance and unnecessary movements during gear shifting, and improve the response speed and stability of the entire transmission system.

[0051] The first inclined section 201 , the connecting section 202 and the second inclined section 203 are configured in a V-shaped structure, and the open ends thereof are disposed toward the second shift groove 3 .

[0052] In this embodiment, the first inclined section 201, the connecting section 202 and the second inclined section 203 together form a V-shaped structure. This design is not only visually and sensory intuitive and easy to understand, but more importantly, it can provide guidance and restraint for the first shift fork 4, so that the first shift fork 4 moves along a preset V-shaped trajectory, thereby realizing the selection of different gears. The open end of the V-shaped structure points to the second shift groove 3, indicating that there is interactivity and continuity between the first shift groove 2 and the second shift groove 3. During the shifting process, the first shift groove 2 and the second shift groove 3 need to participate in the shifting together to ensure the continuity and accuracy of the shifting operation. Such a design is conducive to simplifying the shifting operation process, reducing the shifting time, and also improving the stability and reliability of the shifting. The V-shaped structure helps to physically disperse or absorb the stress generated during the shifting, reduce wear, and extend the service life.

[0053] The connecting section 202 is located at the closed end of the V-shaped structure, and the connecting section 202 has a transition point perpendicular to the axial direction of the first power shaft 6 .

[0054] In this embodiment, the connecting section 202 is arranged at the closed end of the V-shaped structure. The purpose is to use the connecting section 202 as the core area for force transmission or direction conversion during the gear shifting process, to ensure that the first shift fork 4 can smoothly transition when sliding between the first inclined section 201 or the second inclined section 203, and the transition point perpendicular to the first power shaft 6 helps to achieve faster power cut-off and reconnection at the moment of gear shifting, reduce gear shifting shock, and improve gear shifting smoothness. At the same time, it is also convenient to achieve more precise engagement between different gears, because the point change perpendicular to the power shaft can better match the alignment requirements of gears in different gears, thereby ensuring the accuracy and efficiency of gear shifting.

[0055] The second shift groove 3 includes a third inclined section 301, a fourth inclined section 302 and a fifth inclined section 303 connected in sequence, wherein the distal ends of the third inclined section 301 and the fourth inclined section 302 are inclined in different directions, and the distal ends of the fourth inclined section 302 and the fifth inclined section 303 are inclined in different directions.

[0056] In this embodiment, the second shift groove 3 includes a third inclined section 301, a fourth inclined section 302 and a fifth inclined section 303 which are connected in sequence, and the distal ends of the third inclined section 301 and the fourth inclined section 302 are respectively inclined in different directions, and the distal ends of the fourth inclined section 302 and the fifth inclined section 303 are also inclined in different directions. Through the coordinated work of the first shift groove 2 and the second shift groove 3, the first shift fork 4 and the second shift fork 5 slide synchronously, and the shifting action is completed smoothly and reliably. Preferably, a notch 304 is formed between the third inclined section 301, the fourth inclined section 302 and the fifth inclined section 303, and the notch 304 is arranged toward the first shift groove 2; preferably, the fifth inclined section 303 is provided with a corner point 305 bent in the direction of the notch 304, and the notch 304 and the corner point 305 are designed so that when the first shift fork 4 slides in the first shift groove 2, the second shift fork 5 can form a tight coordination with the first shift fork 4 when it is in any position in the second shift groove 3, and the notch 304 provides a clear path indication for the second shift fork 5, so that the second shift fork 5 can quickly disengage from the current gear and prepare to enter the next predetermined gear. Such a design can effectively reduce the shifting time and improve the smoothness of the shifting and the driving experience. The fifth inclined section 303 is provided with a corner point 305 that bends toward the notch 304. The corner point 305 not only affects the movement trajectory of the second shift fork 5 on the fifth inclined section 303, but also, through such a curved design, can achieve more precise control of the shifting force and provide a clear tactile feedback point during the shifting process to help the driver perceive the shifting progress. At the same time, it also facilitates the second shift fork 5 to transition more smoothly from the fifth inclined section 303 to the notch 304, thereby improving the consistency and accuracy of the shifting operation. Secondly, such a design can serve as a "turning point" in mechanics to physically assist in completing the shifting action and reduce unnecessary force consumption or the risk of misoperation. The design of the curved corner point 305 can also enhance the driver's control experience. When the operator feels this specific bending point, it can serve as a signal to prompt that the gear shift is about to be completed or that additional force needs to be applied to complete the gear shift, thereby increasing the interactivity of the gear shift process. By setting such a special corner point 305 in the fifth inclined section 303, not only the function of a single component is optimized, but also the overall improvement of the entire gear shift system in terms of operational convenience, response speed and durability is promoted.

[0057] The shifting structure also includes a driving member for driving the shifting plate 1 to rotate forward and reverse, the driving member includes a meshing pawl 10 and a ratchet gear 11, and a driving shaft for connecting the ratchet gear 11 and the shifting plate 1, the ratchet gear 11 has three ratchet grooves, so that when the pawl 10 is driven by an external force to rotate, the ratchet gear 11 is linked to rotate, and respectively correspond to the first gear state, the second gear state and the third gear state.

[0058] In this embodiment, the driving member is used to drive the shift plate 1 to rotate forward and reverse to achieve upshift or downshift. The driving member includes a ratchet pawl and a ratchet gear 11 that are mutually internal. The ratchet pawl and the ratchet gear 11 are connected by a driving shaft (not shown). The shift plate 1 is precisely controlled by mechanical transmission of the ratchet gear 11 and the driving shaft. The ratchet gear 11 is provided with three ratchet grooves, each of which corresponds to a gear state, such as first gear, second gear and third gear, so that when the external driving force causes the ratchet gear 11 to rotate through the pawl 10, each ratchet groove of the ratchet gear 11 can be aligned with the corresponding gear state. The corresponding gear shifting mechanism cooperates to accurately locate the required gear and realize the gear switching. Through the rotation of the ratchet mechanism, not only the forward (upshift) and reverse (downshift) gear shifting can be realized, but also each gear shifting action can be ensured to be accurate and reliable. The design of the ratchet groove ensures that each gear shift directly corresponds to a specific gear, avoiding ambiguous or wrong gear selection, and improving the stability and safety of the gear shifting. Through the simple and efficient ratchet and pawl 10, not only the complexity of the gear shifting operation is simplified, but also the response speed and durability of the entire transmission system are improved.

[0059] An engine 14 includes a first drive gear 12, a second drive gear 13, and the above-mentioned shifting structure, wherein the first drive gear 12 and the second drive gear 13 are respectively arranged on the first power shaft 6 and the second power shaft 7, and the first drive gear 12 is meshed with the power gear 605.

[0060] In this embodiment, the engine 14 is provided with a first drive gear 12 and a second drive gear 13. The first drive gear 12 is used to mesh with the power gear 605 on the first power shaft 6, and is responsible for transmitting the power generated by the engine 14 to the gear shifting system. This direct meshing relationship ensures the directness and efficiency of power transmission. The second power gear 605 is used to receive the power transmitted by the first power gear 605, and output the current gear information of the gear shifting structure as power.

[0061] A tricycle is provided, using the engine 14 described above. The specific structure of the tricycle refers to the above embodiment. Since the tricycle adopts all the technical solutions of the above embodiment, it has at least all the beneficial effects brought by the technical solutions of the above embodiment, which will not be described one by one here.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the 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 gear shifting structure, characterized in that: include: A shift plate having a first shift groove and a second shift groove; A first shift fork, slidably disposed in the first shift groove; A second shift fork is slidably disposed in the second shift groove, and the first shift fork and the second shift fork are connected via a shift fork shaft; A first power shaft, coaxially sleeved with a power gear, a first shift gear and a second shift gear in sequence along its axial direction, a first neutral gear and a second gear gear spaced apart from each other, and the second gear gear is connected to the second shift gear; The second power shaft is coaxially sleeved with a third shift gear, a first linkage gear and a second linkage gear in sequence along its axial direction, the third shift gear is meshed with the power gear, the first linkage gear and the second linkage gear are respectively meshed with the first shift gear and the second shift gear, and a third gear tooth, a second neutral gear tooth and a first gear tooth are sequentially arranged between the third shift gear and the first linkage gear, the third gear tooth is connected with the third shift gear, and the first gear tooth is at least partially hidden in the first linkage gear; A shift member, comprising a first sliding pawl and a second sliding pawl respectively slidably disposed on the first power shaft and the second power shaft, wherein the first sliding pawl and the second sliding pawl are respectively connected to the first shift fork and the second shift fork, and both have internal teeth; Wherein, the shift plate rotates forward and reversely under the action of external force, so as to respectively link the first sliding pawl and the second sliding pawl through the first shift fork and the second shift fork to slide back and forth between the first shift gear and the second shift gear and between the third shift gear and the first linkage gear; In the axial direction of the first power shaft and the second power shaft, the first sliding pawl is selectively engaged with the first neutral gear tooth or the second gear tooth, and the second sliding pawl is selectively engaged with the third gear tooth, the second neutral gear tooth or the first gear tooth to form a first gear state, a second gear state or a third gear state; In the first gear state, the first sliding pawl and the second sliding pawl are respectively engaged with the first neutral gear tooth and the first gear tooth; In the second gear state, the first sliding pawl and the second sliding pawl are respectively engaged with the second gear tooth and the second neutral gear tooth; In the third gear state, the first sliding pawl and the second sliding pawl are respectively engaged with the first neutral gear tooth and the third gear tooth.

2. A shift structure according to claim 1, characterized in that: The first shift groove includes a first inclined section, a connecting section and a second inclined section which are connected in sequence. One end of the first inclined section and one end of the second inclined section converge to opposite ends of the connecting section respectively, and the other ends of the two are inclined in opposite directions respectively.

3. A shift structure according to claim 2, characterized in that: The first inclined section, the connecting section and the second inclined section are constructed in a V-shaped structure, and the open ends thereof are arranged toward the second shift groove.

4. A shift structure according to claim 3, characterized in that: The connecting section is located at the closed end of the V-shaped structure, and the connecting section has a transition point perpendicular to the axial direction of the first power shaft.

5. The shifting structure according to claim 1, characterized in that: The second shift groove includes a third inclined segment, a fourth inclined segment and a fifth inclined segment connected in sequence, the distal ends of the third inclined segment and the fourth inclined segment are inclined in different directions, and the distal ends of the fourth inclined segment and the fifth inclined segment are inclined in different directions.

6. A shift structure according to claim 5, characterized in that: A gap is formed between the third inclined segment, the fourth inclined segment and the fifth inclined segment, and the gap is arranged toward the first shift groove.

7. A shift structure according to claim 6, characterized in that: The fifth inclined section is provided with a corner point bent toward the notch.

8. The shift structure according to claim 1, characterized in that: The shifting structure also includes a driving member for driving the shift plate to rotate forward and reverse, the driving member includes a meshing pawl and a ratchet gear, and a driving shaft for connecting the ratchet gear and the shift plate, the ratchet gear has three ratchet grooves, so that when the pawl is driven to rotate by an external force, the ratchet gear is linked to rotate, and they correspond to the first gear state, the second gear state and the third gear state respectively.

9. An engine, characterized in that: It includes a first driving gear, a second driving gear, and a shifting structure as described in any one of claims 1 to 8, wherein the first driving gear and the second driving gear are respectively arranged on the first power shaft and the second power shaft, and the first driving gear is meshed with the power gear.

10. A tricycle, characterized in that: Comprising an engine as claimed in claim 9.

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