Variable valve structure of motorcycle engine

Abstract

The utility model provides a variable valve structure of a motorcycle engine, and belongs to the technical field of motorcycles. The problem that a variable valve structure of an existing motorcycle engine is large in machining difficulty is solved. According to the variable valve structure of the motorcycle engine, the engine comprises a cylinder body and an air inlet valve, a rocker arm shaft and a cam shaft are arranged in the cylinder body, the variable valve structure comprises an air inlet rocker arm I connected to the rocker arm shaft, an air inlet cam I and an air inlet cam II are arranged on the cam shaft, and one end of the air inlet rocker arm I is connected with the air inlet valve. The rocker arm shaft is connected with a second air inlet rocker arm which abuts against the outer circumferential face of the second air inlet cam and can independently swing relative to the first air inlet rocker arm. The cylinder body is further provided with a clutch assembly capable of combining the first air inlet rocker arm and the second air inlet rocker arm and enabling the first air inlet rocker arm and the second air inlet rocker arm to swing at the same amplitude. The reliability of the variable valve structure can be improved, and meanwhile the machining difficulty of the variable valve structure is lowered.

Description

Technical Field

[0001] The utility model belongs to the technical field of motorcycles and relates to a variable valve structure of a motorcycle engine. Background Technique

[0002] When the engine works, the crankshaft can drive the camshaft to rotate. A cam is fixedly connected to the camshaft. The cam abuts against one end of the rocker arm. The rotating cam can drive the valve to open and close. That is, the cam includes a base circle portion and a lobe tip portion. The base circle portion refers to the portion of the outer wheel surface of the cam that is cylindrical, and the lobe tip portion is the portion of the cam that protrudes from the base circle portion. That is, when the rocker arm abuts against the base circle portion, the valve is in the closed state, and when the lobe tip portion abuts against the rocker arm, the valve opens. However, the size of the above valve opening is fixed, that is, the valve lift is fixed. The speed of the engine will change. When the speed of the engine increases, the demand for the intake air volume increases. An engine with a fixed valve lift will cause incomplete combustion of the gas, affecting emissions and fuel economy.

[0003] In view of the existence of the above problems, a variable valve structure has been derived on the engine. Since the lift size of the intake valve is determined by the shape of the cam on the camshaft, currently, the conventional variable valve structure on motorcycles generally adopts two intake cams with different profiles on the camshaft assembly. By moving the position of the intake cam, the two intake cams with different profiles are respectively brought into contact with the intake valve rocker arm to change the action posture of the intake valve rocker arm and thus change the intake air volume. For example, an engine two-stage adjustable valve lift device (application number: 201711169541.7) disclosed in a patent document. It sleeved a camshaft sleeve on the camshaft. A high-speed cam and a low-speed cam are fixedly connected to the camshaft sleeve. By controlling the needle valve to drive the axial movement of the camshaft sleeve, the high-speed cam and the low-speed cam are switched with each other to realize the variable lift of the intake valve. This type of variable valve structure has some deficiencies: the way that the camshaft sleeve is circumferentially fixed and axially movable relative to the camshaft requires the camshaft sleeve to have high machining accuracy to ensure its stable sliding fit with the camshaft. However, due to the high load and high pressure acting on the high-speed cam and the low-speed cam of the camshaft assembly during the operation of the engine, and it needs to experience millions of reciprocating motions during the operation of the engine. In order to ensure the reliability and durability of the camshaft assembly, the camshaft sleeve, the high-speed cam and the low-speed cam all need to be made of very high-strength materials, which will greatly increase the machining difficulty of the camshaft assembly, making the cutting and machining process of the camshaft assembly more difficult. Therefore, high-end and sophisticated machining equipment often needs to be equipped, resulting in a high processing cost.

[0004] In addition, there is a conventional variable valve structure that adjusts the lift of the intake valve by changing the centrifugal force during engine rotation. For example, a variable valve lift device for a motorcycle tappet engine disclosed in a patent document (Application No.: 201620498502.6). In this device, when the motorcycle engine is running at high speed, the high-speed cam slider overcomes the force of the slider positioning spring, and the high-speed cam slider moves upward. The centrifugal block overcomes the force of the centrifugal block spring and rotates to drive the high-speed rotating shaft to rotate. Then, the high-speed rotating shaft is used to push the high-speed cam slider upward. At this time, the high-speed cam slider drives the rocker arm to rotate, enabling the exhaust valve and the intake valve to have lift. In the actual use of this variable valve structure, there are some deficiencies: the radial displacement of the high-speed cam slider is affected by the centrifugal force, the slider positioning spring, and the centrifugal block spring. However, due to the extension of the use time or other factors, the pre-tightening force of the spring may change, and the elasticity of the spring will become unstable. If the pre-tightening force changes, the reset force of the high-speed cam slider and the centrifugal block will also be affected, which may cause the high-speed cam slider to not return to the proper position, and after resetting, it may still protrude from the surface of the low-speed cam, resulting in abnormal valve lift and affecting the reliability of the variable valve structure. Summary of the Invention

[0005] The purpose of the present utility model is to address the above-mentioned problems existing in the prior art and propose a variable valve structure for a motorcycle engine. The present utility model can improve the reliability of the variable valve structure and reduce the processing difficulty at the same time.

[0006] The purpose of the present utility model can be achieved by the following technical solutions: A variable valve structure for a motorcycle engine, the engine includes a cylinder block and an intake valve, a rocker shaft and a camshaft are provided in the cylinder block. The variable valve structure includes an intake rocker arm one connected to the rocker shaft. It is characterized in that the camshaft has an intake cam one and an intake cam two, and the lobe tip of the intake cam two is higher than the lobe tip of the intake cam one. One end of the intake rocker arm one is connected to the intake valve, and the other end abuts against the outer peripheral surface of the intake cam one. An intake rocker arm two that abuts against the outer peripheral surface of the intake cam two and can swing independently relative to the intake rocker arm one is also connected to the rocker shaft. A clutch assembly is further provided on the cylinder block to combine the intake rocker arm one and the intake rocker arm two and enable the intake rocker arm one and the intake rocker arm two to swing with the same amplitude.

[0007] When the motorcycle is running at a low speed and the engine is at a low rotational speed, the clutch assembly is in a disengaged state, causing the intake rocker arm 1 and the intake rocker arm 2 to swing independently. At this time, the lift of the intake valve is controlled by the intake rocker arm 1, and the intake rocker arm 2 does not abut against the intake valve, so its movement does not affect the lift of the intake valve. Since the lobe tip of the intake cam 1 is relatively low, the lift of the intake valve and the intake air volume are relatively small during this process. When the motorcycle is running at a high speed and the engine is at a high rotational speed, the clutch assembly switches to the engaged state, causing the intake rocker arm 1 and the intake rocker arm 2 to be combined. At this time, the intake rocker arm 2 drives the intake rocker arm 1 to swing with the same amplitude. Since the intake rocker arm 2 abuts against the outer peripheral surface of the intake cam 2 and the lobe tip of the intake cam 2 is higher than that of the intake cam 1, the swing amplitude of the intake rocker arm 1 increases to be the same as that of the intake rocker arm 2, thereby increasing the lift of the intake valve and the intake air volume, ensuring more complete combustion of the engine, reducing emissions, and optimizing the engine performance.

[0008] This variable valve structure meets the design requirements of variable valve lift through the unique design of adding the intake rocker arm 2 and the clutch assembly. In this design, there is no need to machine a complex special-shaped surface on the camshaft surface to achieve the switching of the intake valve lift. Therefore, it can avoid the situation where too complex a shape makes the cutting and machining process of the camshaft more difficult, thereby reducing the machining cost of the camshaft assembly.

[0009] In addition, in this design, since the positions of the intake cam 1 and the intake cam 2 do not need to change relative to the camshaft, the intake cam 1 and the intake cam 2 can be integrally formed with the camshaft. In this way, even after the motorcycle has been used and driven for a long time, when the clutch assembly switches between the disengaged state and the engaged state, the change amplitude of the valve lift can always remain consistent, and there will be no situation where the intake valve lift is abnormal due to the failure of the high-speed cam slider to reset properly after a long time of use as in the prior art patent "A Variable Valve Lift Device for a Motorcycle Tappet Engine (Application No.: 201620498502.6)". Therefore, this variable valve structure has good reliability and working stability.

[0010] In the variable valve structure of the motorcycle engine described above, the top of the first intake rocker arm has a first linkage portion, and the top of the second intake rocker arm has a second linkage portion. The clutch assembly includes a driving member and a linkage pin arranged parallel to the camshaft. The linkage pin axially slides through the second linkage portion, and a pin hole matching the outer diameter of the linkage pin is formed in the first linkage portion. The driving member can push the linkage pin to move so that one end of the linkage pin extends into the pin hole to combine the first intake rocker arm and the second intake rocker arm. The linkage pin axially slides through the second linkage portion, ensuring that the linkage pin can stably perform axial movement. After the engine speed increases, the driving member pushes the linkage pin. When the linkage pin is aligned with the pin hole, the linkage pin can extend into the pin hole, and the linkage pin still remains in the pin hole under the pushing force of the driving member. At this time, the first intake rocker arm and the second intake rocker arm are combined, and the second intake rocker arm drives the first intake rocker arm to swing with the same swing amplitude, thereby increasing the lift of the intake valve and the intake air volume. This clutch assembly mainly realizes the clutch function of the clutch assembly through the improvement of the structures of the first intake rocker arm and the second intake rocker arm, without the need for major structural improvements to the camshaft assembly with high strength, so the manufacturing and processing difficulty and processing cost can be reduced.

[0011] In the variable valve structure of the motorcycle engine described above, a return spring is further provided on the second intake rocker arm to drive the linkage pin out of the pin hole so that the first intake rocker arm and the second intake rocker arm swing independently. When the engine speed decreases, the driving member retracts and releases the linkage pin. The linkage pin is disengaged from the pin hole under the action of the return spring. At this time, the first intake rocker arm and the second intake rocker arm swing independently, the lift of the intake valve decreases, and the intake air volume decreases. Using the return spring to realize the reset of the linkage pin has the advantages of good reliability and low cost.

[0012] In the variable valve structure of the motorcycle engine described above, the opposite end faces of the first linkage portion and the second linkage portion are both flat, and the first linkage portion and the second linkage portion are close to or in contact with each other. This structure can ensure that the first linkage portion and the second linkage portion are close in position, facilitating the stable and smooth extension or retraction of the linkage pin into or out of the pin hole, and improving the operation stability and reliability of this variable valve structure.

[0013] In the variable valve structure of the motorcycle engine described above, the end of the linkage pin that can extend into the pin hole is the front end, and the other end is the rear end. The driving member is an electromagnet fixedly connected to the cylinder block. A driving shaft is coaxially arranged between the driving member and the linkage pin. One end face of the driving shaft abuts against the rear end face of the linkage pin, and the driving member can push the other end face of the driving shaft and drive the driving shaft to axially move. The electromagnet is a prior art and can be directly purchased in the market. When current passes through the coil of the electromagnet, a magnetic field is generated, and the movement of the driving shaft is driven by the attraction or repulsion of the magnetic force. Using the electromagnet to move the linkage pin has the advantages of high efficiency and good reliability.

[0014] In the variable valve structure of the motorcycle engine described above, the second linkage part is in the shape of a sleeve. An installation hole is provided inside the second linkage part along its axial direction. The linkage pin is arranged in the installation hole. A guiding convex edge is provided on the outer wall of the linkage pin along the circumferential direction and is in sliding fit with the inner wall of the installation hole. The return spring is sleeved on the linkage rod, and both ends of the return spring are respectively abutted against the guiding convex edge and the inner wall of the installation hole. The sleeve-shaped second linkage part is relatively convenient to manufacture, and the axial sliding of the linkage pin can be ensured stably through the installation hole of the second linkage part, improving the stability and reliability of the operation of the clutch assembly. Both ends of the return spring are respectively abutted against the guiding convex edge and the inner wall of the installation hole, so that the linkage pin can smoothly escape from the pin hole under the action of the return spring.

[0015] In the variable valve structure of the motorcycle engine described above, a first rocker arm hole is provided on the first intake rocker arm, and a second rocker arm hole is provided on the second intake rocker arm. The rocker shaft passes through the first rocker arm hole and the first rocker arm hole respectively. A first mating plane is provided on the end surface of the first intake rocker arm facing the second intake rocker arm and is arranged around the first rocker arm hole. A second mating plane is provided on the end surface of the second intake rocker arm facing the first intake rocker arm and is arranged around the second rocker arm hole. The first mating plane and the second mating plane are abutted against each other. The first intake rocker arm and the second intake rocker arm are respectively sleeved on the rocker shaft through the first rocker arm hole and the second rocker arm hole, which can make the installation of the first intake rocker arm and the second intake rocker arm convenient and have good installation stability. By providing the first mating plane and the second mating plane and making them abutted against each other, the operation precision of the first intake rocker arm and the second intake rocker arm can be improved, avoiding the situation that the installation position deviates and the concentricity between the linkage pin and the pin hole decreases due to the reduction of the operation precision of the first intake rocker arm or the second intake rocker arm, and further avoiding the situation that the linkage pin is difficult to extend into the pin hole, so as to ensure that the variable valve structure has high operation stability and reliability.

[0016] In the variable valve structure of the motorcycle engine described above, a first linkage part is provided at the top of the first intake rocker arm, and a second linkage part is provided at the top of the second intake rocker arm. The clutch assembly includes a linkage pin arranged parallel to the camshaft and an electric push rod fixed on the cylinder block. The linkage pin axially slides through the second linkage part. A pin hole matching the outer diameter of the linkage pin is provided on the first linkage part. The rear end of the linkage pin extends out of the second linkage part, and a bent part is provided at the rear end of the linkage pin. A tension spring is connected to the bent part and can drive the axial movement of the linkage pin and make the front end of the linkage pin extend into the pin hole. The electric push rod has a telescopic rod arranged parallel to the linkage pin and capable of axial expansion and contraction. The end surface of the telescopic rod abuts against the bent part and can push the linkage pin out of the pin hole.

[0017] The electric push rod is a prior art and can be directly purchased on the market. Its principle is to convert the rotary motion of the motor into a linear motion and complete the telescopic rod action by the forward and reverse rotation of the motor. When the engine speed increases, the electric push rod retracts, and the linkage pin can extend into the pin hole under the action of the tension spring. At this time, the intake rocker arm one and the intake rocker arm two are combined, so that the intake rocker arm two drives the intake rocker arm one to swing with the same swing amplitude, thereby increasing the lift of the intake valve and the intake air volume. When the engine speed decreases, the telescopic rod of the electric push rod ejects, thereby driving the linkage pin to move away from the pin hole and disengaging the linkage pin from the pin hole. At this time, the intake rocker arm one and the intake rocker arm two swing independently, and the lift of the engine intake valve decreases, and the intake air volume decreases.

[0018] In the variable valve structure of the motorcycle engine described above, a guide hole is provided on the cylinder block, the drive shaft is slidably arranged in the guide hole, and the driving member is fixedly connected to the outer wall of the cylinder block. The electromagnet is fixedly connected to the outer wall of the cylinder block, which is convenient for the installation and maintenance of the electromagnet. By providing the guide hole and the drive shaft in sliding fit, the running accuracy of the drive shaft can be improved, so as to ensure that the drive shaft can stably and accurately push the linkage shaft to move, and improve the stability and reliability of the device.

[0019] In the variable valve structure of the motorcycle engine described above, a stepped hole communicating with the guide hole is provided on the outer wall of the cylinder block, and a oil seal is sleeved on the drive shaft, and the oil seal is in sealing fit with the inner wall of the stepped hole. In order to ensure the smooth movement of the drive shaft, a lubricating substance such as grease will be applied to the drive shaft. At this time, by providing the oil seal, the pollution of the grease by the external environment can be isolated and the leakage of the grease can be avoided, so as to ensure that the drive shaft can always stably and accurately push the linkage shaft to move.

[0020] Compared with the prior art, the variable valve structure of the motorcycle engine has the following advantages:

[0021] 1. The variable valve structure meets the design requirements of variable valve lift through the unique design of adding the intake rocker arm two and the clutch assembly. In this design, the intake cam one and the intake cam two are integrally formed on the camshaft. Therefore, the intake cam one and the intake cam two can be synchronously processed and formed with the camshaft, and there is no need to machine a complex special-shaped surface on the surface of the camshaft to realize the switching of the intake valve lift. Therefore, the situation that too complex a shape makes the cutting and processing process of the camshaft more difficult can be avoided, thereby reducing the processing cost of the camshaft assembly.

[0022] 2. Since the intake cam 1 and the intake cam 2 are integrally formed on the camshaft, the positions of the intake cam 1 and the intake cam 2 will not change relative to the camshaft. Even after the motorcycle has been used and driven for a long time, when the clutch assembly switches between the disengaged state and the engaged state, the change amplitude of the intake valve lift can always remain consistent. Therefore, this variable valve structure has good reliability and working stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural diagram of a motorcycle engine.

[0024] Figure 2 is a schematic structural diagram inside the cylinder block.

[0025] Figure 3 is a schematic structural diagram of this variable valve structure.

[0026] Figure 4 is a schematic structural diagram of the camshaft, the intake rocker arm 1, and the intake rocker arm 2 in this variable valve structure.

[0027] Figure 5 is a partial cross-sectional view of this variable valve structure when the intake rocker arm 1 and the intake rocker arm 2 swing independently.

[0028] Figure 6 is a partial cross-sectional view of this variable valve structure when the intake rocker arm 1 and the intake rocker arm 2 are combined.

[0029] Figure 7 is a side view of the camshaft.

[0030] Figure 8 is an explosion diagram of the intake rocker arm 1, the intake rocker arm 2, the return spring, and the linkage pin Figure One .

[0031] Figure 9 An explosion diagram of the intake rocker arm 1, the intake rocker arm 2, the return spring, and the linkage pin Figure Two .

[0032] Figure 10 is a partial cross-sectional view of the variable valve structure in Embodiment 2 when the intake rocker arm 1 and the intake rocker arm 2 swing independently.

[0033] Figure 11 is a partial cross-sectional view of the variable valve structure in Embodiment 2 when the intake rocker arm 1 and the intake rocker arm 2 are combined.

[0034] In the figure, 1 is the cylinder block; 1a is the guide hole; 1b is the stepped hole; 2 is the rocker shaft; 3 is the camshaft; 31 is the first intake cam; 32 is the second intake cam; 33 is the exhaust cam; 4 is the first intake rocker; 41 is the first linkage part; 411 is the pin hole; 42 is the first rocker hole; 43 is the first mating plane; 5 is the intake valve; 6 is the second intake rocker; 61 is the second linkage part; 611 is the mounting hole; 62 is the second rocker hole; 63 is the second mating plane; 7 is the driving part; 71 is the driving shaft; 8 is the linkage pin; 81 is the guide flange; 82 is the bent part; 9 is the return spring; 10 is the electric push rod; 101 is the telescopic rod; 11 is the tension spring; 12 is the oil seal; 13 is the torsion spring; 14 is the exhaust rocker; 15 is the exhaust valve. Detailed implementation mode

[0035] The following are specific embodiments of the present invention and in combination with the accompanying drawings, the technical solutions of the present invention will be further described, but the present invention is not limited to these embodiments.

[0036] Embodiment 1

[0037] As Figures 1 to 3 shown, in the variable valve structure of this motorcycle engine, the engine includes a cylinder block 1. Inside the cylinder block 1, there are a rocker shaft 2 and a camshaft 3. Inside the cylinder block 1, there is also an exhaust rocker 14. The first intake rocker 4 is hinged on the rocker shaft 2. The camshaft 3 is integrally formed with the first intake cam 31, the second intake cam 32 and the exhaust cam 33. One end of the exhaust rocker 14 is connected to the exhaust valve 15, and the other end abuts against the exhaust cam 33. As Figure 4 and Figure 7 shown, the tip of the second intake cam 32 is directly opposite to and higher than the tip of the first intake cam 31. One end of the first intake rocker 4 is connected to the intake valve 5, and the other end abuts against the outer peripheral surface of the first intake cam 31. The second intake rocker 6 that can swing independently relative to the first intake rocker 4 is also hinged on the rocker shaft 2. A torsion spring 13 is sleeved on the second intake rocker 6. By relying on the action of the torsion spring 13, one end of the second intake rocker 6 can always abut against the outer peripheral surface of the second intake cam 32. The cylinder block 1 is also provided with a clutch assembly that can combine the first intake rocker 4 and the second intake rocker 6 and enable the first intake rocker 4 and the second intake rocker 6 to swing with the same amplitude.

[0038] Combined with Figure 5 、 Figure 6 、 Figure 8 and Figure 9As shown in the figure, the top of the intake rocker arm 1-4 has a linkage part 1-41, and the top of the intake rocker arm 2-6 has a linkage part 2-61. The clutch assembly includes a driving part 7 and a linkage pin 8 arranged parallel to the camshaft 3. The linkage pin 8 axially slides through the linkage part 2-61, and a pin hole 411 matching the outer diameter of the linkage pin 8 is formed in the linkage part 1-41. The driving part 7 can push the linkage pin 8 to move so that one end of the linkage pin 8 extends into the pin hole 411 to combine the intake rocker arm 1-4 and the intake rocker arm 2-6. The linkage pin 8 axially slides through the linkage part 2-61, ensuring that the linkage pin 8 can stably perform axial movement. A return spring 9 is further provided on the intake rocker arm 2-6 to drive the linkage pin 8 out of the pin hole 411 so that the intake rocker arm 1-4 and the intake rocker arm 2-6 can swing independently. The opposite end faces of both the linkage part 1-41 and the linkage part 2-61 are flat surfaces, and the linkage part 1-41 and the linkage part 2-61 are close to or abutted against each other. This structure can ensure that the positions of the linkage part 1-41 and the linkage part 2-61 are close, facilitating the stable and smooth extension or retraction of the linkage pin 8 into or out of the pin hole 411, and improving the operation stability and reliability of the variable valve structure.

[0039] As Figure 5 and Figure 6 shown in the figure, the end of the linkage pin 8 that can extend into the pin hole 411 is the front end, and the other end is the rear end. The driving part 7 is an electromagnet fixedly connected to the cylinder block 1. A driving shaft 71 is coaxially arranged between the driving part 7 and the linkage pin 8. One end face of the driving shaft 71 abuts against the rear end face of the linkage pin 8, and the driving part 7 can push the other end face of the driving shaft 71 and drive the driving shaft 71 to axially move. The linkage part 2-61 is in a sleeve shape, and an installation hole 611 is arranged axially inside the linkage part 2-61. The linkage pin 8 is slidably arranged in the installation hole 611. A guiding convex edge 81 is arranged circumferentially on the outer wall of the linkage pin 8 and slidably cooperates with the inner wall of the installation hole 611. The return spring 9 is sleeved on the linkage rod and is located inside the installation hole 611. The two ends of the return spring 9 respectively abut against the guiding convex edge 81 and the inner wall of the installation hole 611.

[0040] As Figure 5 、 Figure 8 and Figure 9 shown in the figure, the intake rocker arm 1-4 has a rocker arm hole 1-42, and the intake rocker arm 2-6 has a rocker arm hole 2-62. The rocker shaft 2 respectively passes through the rocker arm hole 1-42 and the rocker arm hole 1-42. On the end face of the intake rocker arm 1-4 facing the intake rocker arm 2-6, a mating plane 1-43 is arranged around the rocker arm hole 1-42. On the end face of the intake rocker arm 2-6 facing the intake rocker arm 1-4, a mating plane 2-63 is arranged around the rocker arm hole 2-62. The mating plane 1-43 and the mating plane 2-63 are abutted against each other. The intake rocker arm 1-4 and the intake rocker arm 2-6 are respectively sleeved on the rocker shaft 2 through the rocker arm hole 1-42 and the rocker arm hole 2-62, facilitating the installation of the intake rocker arm 1-4 and the intake rocker arm 2-6 and ensuring good installation stability.

[0041] As Figure 5 and Figure 6 shown, a guide hole 1a is formed in the cylinder block 1, the drive shaft 71 is slidably arranged in the guide hole 1a, and the drive member 7 is fixedly connected to the outer wall of the cylinder block 1. A stepped hole 1b communicating with the guide hole 1a is formed in the outer wall of the cylinder block 1, an oil seal 12 is sleeved on the drive shaft 71, and the oil seal 12 is in sealing fit with the inner wall of the stepped hole 1b. In order to ensure the smooth movement of the drive shaft 71, a lubricating substance such as grease is applied to the drive shaft 71. At this time, by providing the oil seal 12, the pollution of the grease by the external environment can be isolated and the leakage of the grease can be avoided, so as to ensure that the drive shaft 71 can always stably and accurately press the linkage shaft to move.

[0042] The working principle of this variable valve structure will be introduced below in conjunction with the accompanying drawings:

[0043] When the motorcycle is running at a low speed and the engine is at a low speed, as Figure 5 shown, the linkage pin 8 does not extend into the pin hole 411. At this time, the clutch assembly is in a disengaged state, and the intake rocker arm one 4 and the intake rocker arm two 6 swing independently. At this time, the lift of the intake valve 5 is controlled by the intake rocker arm one 4, and the intake rocker arm two 6 does not abut against the intake valve 5, so its movement will not affect the lift of the intake valve 5. And because the lobe tip of the intake cam one 31 is relatively low, the lift of the intake valve 5 is small and the intake air volume is small during this process.

[0044] When the engine speed increases, the drive member 7 pushes the linkage pin 8. When the linkage pin 8 is aligned with the pin hole 411, the linkage pin 8 can extend into the pin hole 411, and the linkage pin 8 is still fixed in the pin hole 411 under the pushing force of the drive member 7. At this time, the force and the assembly are in a combined state, so that the intake rocker arm one 4 and the intake rocker arm two 6 are combined. As Figure 6 shown, at this time, the intake rocker arm two 6 drives the intake rocker arm one 4 to swing with the same swing amplitude. At this time, because the intake rocker arm two 6 abuts against the outer peripheral surface of the intake cam two 32 and the lobe tip of the intake cam two 32 is higher than the lobe tip of the intake cam one 31, the swing amplitude of the intake rocker arm one 4 is increased to be the same as that of the intake rocker arm two 6, so that the lift of the intake valve 5 is increased and the intake air volume is increased, ensuring more complete combustion of the engine, reducing emissions, and optimizing the engine performance.

[0045] When the engine speed decreases, the drive member 7 retracts and releases the linkage pin 8, and the linkage pin 8 is disengaged from the pin hole 411 under the action of the return spring 9 to realize the independent swing of the intake rocker arm one 4 and the intake rocker arm two 6. As Figure 5 shown, at this time, the lift of the intake valve 5 is reduced and the intake air volume is reduced.

[0046] Embodiment 2

[0047] The structure and principle of this embodiment are basically the same as those of the first embodiment, except that: Figure 10 and Figure 11 As shown, the top of the intake rocker arm 1 4 has a linkage part 1 41, the top of the intake rocker arm 2 6 has a linkage part 2 61, the clutch assembly includes a linkage pin 8 arranged in parallel with the camshaft 3 and an electric push rod 10 fixedly connected to the cylinder body 1, the linkage pin 8 is slidably arranged on the linkage part 2 61 along its axial direction, and a pin hole 411 matching the outer diameter of the linkage pin 8 is opened on the linkage part 1 41, the rear end of the linkage pin 8 extends out of the linkage part 2 61, and the rear end of the linkage pin 8 has a bending part 82, and the bending part 82 is connected with a tension spring 11 that can drive the linkage pin 8 to move axially and make the front end of the linkage pin 8 extend into the pin hole 411, the electric push rod 10 has a telescopic rod 101 arranged in parallel with the linkage pin 8 and can be axially telescopic, the end face of the telescopic rod 101 abuts against the bending part 82 and can push the linkage pin 8 out of the pin hole 411.

[0048] The electric push rod 10 is a prior art and can be directly purchased in the market. Its principle is to convert the rotational motion of the motor into linear motion and use the forward and reverse rotation of the motor to complete the movement of the telescopic rod 101. Figure 11 As shown, when the engine speed increases, the electric push rod 10 retreats, and the linkage pin 8 can extend into the pin hole 411 under the action of the tension spring 11. At this time, the intake rocker arm 1 4 and the intake rocker arm 2 6 are combined, so that the intake rocker arm 2 6 swings with the intake rocker arm 1 4 with the same swing amplitude, thereby increasing the lift of the intake valve 5 and the intake volume. Figure 10 As shown, when the engine speed decreases, the telescopic rod 101 of the electric push rod 10 is pushed out, thereby driving the linkage pin 8 to move away from the pin hole 411 and causing the linkage pin 8 to escape from the pin hole 411. At this time, the intake rocker arm 1 4 and the intake rocker arm 2 6 swing independently, the lift of the engine intake valve 5 decreases, and the intake volume decreases.

[0049] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0050] Although terms such as 1, cylinder block; 1a, guide hole; 1b, stepped hole; 2, rocker shaft; 3, camshaft; 31, intake cam 1; 32, intake cam 2; 33, exhaust cam; 4, intake rocker 1; 41, linkage part 1; 411, pin hole; 42, rocker hole 1; 43, mating plane 1; 5, intake valve; 6, intake rocker 2; 61, linkage part 2; 611, mounting hole; 62, rocker hole 2; 63, mating plane 2; 7, driving part; 71, driving shaft; 8, linkage pin; 81, guide rib; 82, bent part; 9, return spring; 10, electric push rod; 101, telescopic rod; 11, tension spring; 12, oil seal; 13, torsion spring; 14, exhaust rocker; 15, exhaust valve are used more frequently in this text, it does not exclude the possibility of using other terms. These terms are used only for more convenient description and explanation of the essence of the present utility model; interpreting them as any kind of additional limitation is contrary to the spirit of the present utility model.

Claims

1. A variable valve structure for a motorcycle engine, the engine comprising a cylinder block (1) and an intake valve (5), a rocker shaft (2) and a camshaft (3) being arranged in the cylinder block (1), the variable valve structure comprising an intake rocker arm I (4) connected to the rocker shaft (2), characterized in that, The camshaft (3) is provided with an intake cam one (31) and an intake cam two (32). The nose part of the intake cam two (32) is higher than that of the intake cam one (31). One end of the intake rocker one (4) is connected to the intake valve (5), and the other end abuts against the outer peripheral surface of the intake cam one (31). The rocker shaft (2) is further connected with an intake rocker two (6) which abuts against the outer peripheral surface of the intake cam two (32) and can swing independently relative to the intake rocker one (4). The cylinder block (1) is further provided with a clutch assembly which can combine the intake rocker one (4) and the intake rocker two (6) and make the intake rocker one (4) and the intake rocker two (6) swing with the same amplitude.

2. The variable valve structure of the motorcycle engine according to claim 1, characterized in that, The top of the intake rocker one (4) has a linkage part one (41), and the top of the intake rocker two (6) has a linkage part two (61). The clutch assembly includes a driving part (7) and a linkage pin (8) arranged parallel to the camshaft (3). The linkage pin (8) axially slides through the linkage part two (61). A pin hole (411) matching the outer diameter of the linkage pin (8) is formed in the linkage part one (41). The driving part (7) can push the linkage pin (8) to move so that one end of the linkage pin (8) extends into the pin hole (411) to combine the intake rocker one (4) and the intake rocker two (6).

3. The variable valve structure of a motorcycle engine according to claim 2, characterized in that, The intake rocker two (6) is further provided with a return spring (9) which can drive the linkage pin (8) to disengage from the pin hole (411) so that the intake rocker one (4) and the intake rocker two (6) swing independently.

4. The variable valve structure of a motorcycle engine according to claim 2, wherein, The opposite end faces of the linkage part one (41) and the linkage part two (61) are both flat surfaces, and the linkage part one (41) and the linkage part two (61) are close to or abut against each other.

5. The variable valve structure of a motorcycle engine according to claim 2 or 3 or 4, characterized in that, One end of the linkage pin (8) that can extend into the pin hole (411) is the front end, and the other end is the rear end. The driving part (7) is an electromagnet fixed on the cylinder block (1). A driving shaft (71) is coaxially arranged between the driving part (7) and the linkage pin (8). One end face of the driving shaft (71) abuts against the rear end face of the linkage pin (8). The driving part (7) can push the other end face of the driving shaft (71) and drive the driving shaft (71) to axially move.

6. The variable valve structure of a motorcycle engine according to claim 3, characterized in that, The linkage part two (61) is in a sleeve shape. An installation hole (611) is arranged axially in the linkage part two (61). The linkage pin (8) is arranged in the installation hole (611). A guiding convex edge (81) is arranged circumferentially on the outer wall of the linkage pin (8) and is in sliding fit with the inner wall of the installation hole (611). The return spring (9) is sleeved on the linkage pin (8). The two ends of the return spring (9) respectively abut against the guiding convex edge (81) and the inner wall of the installation hole (611).

7. The variable valve structure of a motorcycle engine according to claim 1 or 2 or 3 or 4, characterized in that, The intake rocker arm 1 (4) has a rocker arm hole 1 (42), the intake rocker arm 2 (6) has a rocker arm hole 2 (62), the rocker shaft (2) passes through the rocker arm hole 1 (42) and the rocker arm hole 1 (42) respectively, a mating plane 1 (43) is arranged around the rocker arm hole 1 (42) on the end face of the intake rocker arm 1 (4) facing the intake rocker arm 2 (6), a mating plane 2 (63) is arranged around the rocker arm hole 2 (62) on the end face of the intake rocker arm 2 (6) facing the intake rocker arm 1 (4), and the mating plane 1 (43) and the mating plane 2 (63) are in abutment with each other.

8. The variable valve structure of the motorcycle engine according to claim 1, characterized in that, The top of the intake rocker arm 1 (4) has a linkage part 1 (41), the top of the intake rocker arm 2 (6) has a linkage part 2 (61), the clutch assembly includes a linkage pin (8) arranged in parallel with the camshaft (3) and an electric push rod (10) fixed on the cylinder block (1), the linkage pin (8) axially slides through the linkage part 2 (61), a pin hole (411) matching the outer diameter of the linkage pin (8) is formed in the linkage part 1 (41), the rear end of the linkage pin (8) extends out of the linkage part 2 (61), and the rear end of the linkage pin (8) has a bent part (82), a tension spring (11) which can drive the linkage pin (8) to axially move and make the front end of the linkage pin (8) extend into the pin hole (411) is connected to the bent part (82), the electric push rod (10) has a telescopic rod (101) arranged in parallel with the linkage pin (8) and capable of axially telescoping, and the end face of the telescopic rod (101) abuts against the bent part (82) and can push the linkage pin (8) out of the pin hole (411).

9. The variable valve structure of a motorcycle engine according to claim 5, characterized in that, A guide hole (1a) is formed in the cylinder block (1), and the drive shaft (71) is slidably arranged in the guide hole (1a), and the driving part (7) is fixed on the outer wall of the cylinder block (1).

10. The variable valve structure of a motorcycle engine according to claim 9, characterized in that, A stepped hole (1b) communicating with the guide hole (1a) is formed in the outer wall of the cylinder block (1), an oil seal (12) is sleeved on the drive shaft (71), and the oil seal (12) is in sealing fit with the inner wall of the stepped hole (1b).

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