Variable valve structure of engine

Abstract

The utility model provides a variable valve structure of an engine, and belongs to the technical field of motorcycles. The variable valve structure solves the problems that an existing variable valve structure of an engine is large in machining difficulty and high in machining cost. According to the variable valve structure of the 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, a first air inlet cam and a second air inlet cam are arranged on the cam shaft, and the variable valve structure comprises a first air inlet rocker arm and a second air inlet rocker arm which are arranged on the rocker arm shaft. The second air inlet rocker arm can abut against the peripheral face of the second air inlet cam all the time under the action of the first reset spring, a cylindrical sleeve part is arranged at the top of the second air inlet rocker arm, a linkage pin is arranged in the sleeve part in a sliding mode, and a pin hole matched with the linkage pin in outer diameter is formed in the top of the first air inlet rocker arm. The cylinder body is provided with a driving assembly capable of pushing the linkage pin to move so that one end of the linkage pin can stretch into the pin hole. On the basis that good reliability of the variable valve structure is guaranteed, the machining difficulty is reduced.

Description

Technical Field

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

[0002] When the engine is working, the crankshaft can drive the camshaft to rotate. A cam is fixedly connected to the camshaft, and the cam is in contact with 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 and a lobe. The base circle refers to the cylindrical part of the outer wheel surface of the cam, and the lobe is the part of the cam that protrudes from the base circle. That is, when the rocker arm is in contact with the base circle, the valve is in a closed state, and when the lobe is in contact with the rocker arm, the valve is open. However, the size of the above-mentioned valve opening is fixed, that is, the valve lift is fixed, and the engine speed will change. When the engine speed increases, the demand for intake air increases. The engine with fixed valve lift will cause incomplete gas combustion, affecting emissions and fuel economy.

[0003] In light of the aforementioned issues, variable valve mechanisms have emerged for engines. Since the lift of the intake valve is determined by the shape of the camshaft cam, conventional variable valve mechanisms on motorcycles currently employ two intake cams with different profiles on the camshaft assembly. By shifting the position of the intake cams, the two intake cams with different profiles are switched to contact the intake rocker arms, thereby changing the motion of the intake rocker arms and, consequently, the intake volume. For example, a patent document discloses a two-stage adjustable valve lift device for an engine (Application No. 201711169541.7). This device utilizes a camshaft sleeve mounted on the camshaft, to which a high-speed cam and a low-speed cam are fixed. A control needle valve drives the camshaft sleeve axially, thereby switching between the high-speed and low-speed cams and achieving variable intake valve lift. This type of variable valve mechanism has several drawbacks: the camshaft sleeve is circumferentially fixed relative to the camshaft and moves axially, requiring high machining precision to ensure a stable sliding fit with the camshaft. However, since the high-speed cam and low-speed cam of the camshaft assembly are subjected to high loads and high pressures during engine operation, they need to undergo millions of reciprocating motions during engine operation. In order to ensure the reliability and durability of the camshaft assembly, the camshaft sleeve, high-speed cam and low-speed cam need to be made of very high-strength materials, which will greatly increase the processing difficulty of the camshaft assembly, making the cutting and processing process of the camshaft assembly more difficult. Therefore, high-end and sophisticated processing equipment is often required, resulting in higher processing costs. Summary of the Invention

[0004] The purpose of the utility model is to solve the above problems in the existing technology and propose a variable valve structure for an engine. The utility model can reduce the difficulty of processing while ensuring the reliability of the variable valve structure.

[0005] The purpose of the utility model can be achieved through the following technical solutions: a variable valve structure of an engine, the engine includes a cylinder body and an intake valve, a rocker shaft and a camshaft are arranged in the cylinder body, and the characteristics are that the camshaft has an intake cam 1 and an intake cam 2, the lobe tip of the intake cam 2 is higher than the lobe tip of the intake cam 1, the variable valve structure includes an intake rocker arm 1 and an intake rocker arm 2 arranged on the rocker arm shaft, the intake rocker arm 1 abuts against the outer peripheral surface of the intake cam 1 and can drive the intake valve to open and close, the A return spring 1 is provided in the cylinder body. Under the action of the return spring 1, the intake rocker arm 2 can always rest against the outer peripheral surface of the intake cam 2. The top of the intake rocker arm 2 has a cylindrical sleeve portion, and a linkage pin parallel to the rocker arm shaft is slidably provided in the sleeve portion. The top of the intake rocker arm 1 is provided with a pin hole matching the outer diameter of the linkage pin. The cylinder body is provided with a driving component that can push the linkage pin to move so that one end of the linkage pin extends into the pin hole. The variable valve structure also includes a return spring 2 that can drive the linkage pin to move and disengage from the pin hole.

[0006] When the motorcycle is traveling at low speed and the engine is at low rpm, the linkage pin is released from the pin hole by the action of return spring 2. At this point, intake rocker arm 1 and intake rocker arm 2 swing independently. Intake valve lift is now controlled by intake rocker arm 1, while intake rocker arm 2 does not abut against the intake valve, so its movement does not affect intake valve lift. Because the lobe of intake cam 1 is lower, intake valve lift is smaller during this process, resulting in less intake air. When the motorcycle is running at high speed and the engine is at high speed, the drive assembly pushes the linkage pin. When the linkage pin is facing the pin hole, the linkage pin can be extended into the pin hole, and the linkage pin is still kept in the pin hole by the pushing force of the drive assembly. At this time, the intake rocker arm 1 and the intake rocker arm 2 are combined, so that the intake rocker arm 2 swings with the intake rocker arm 1 with the same swing amplitude. At this time, since the intake rocker arm 2 is against the outer peripheral surface of the intake cam 2 and the lobe tip of the intake cam 2 is higher than the lobe tip of the intake cam 1, the swing amplitude of the intake rocker arm 1 is increased to the same as the swing amplitude of the intake rocker arm 2, thereby increasing the lift of the intake valve and the intake volume, ensuring more complete engine combustion, reducing emissions, and optimizing engine performance.

[0007] This variable valve structure meets the design requirements of variable valve lift by adding a second intake rocker arm and providing a clutch assembly consisting of a drive assembly, a linkage pin, and a first and second return springs. The sleeve ensures stable movement of the linkage pin, and in conjunction with the first return spring, the second intake rocker arm consistently and reliably abuts the second intake cam, improving the stability of the device and the smoothness of the clutch assembly switching process. Furthermore, the second return spring ensures accurate and timely reset of the linkage pin during low-speed operation, ensuring that the clutch assembly smoothly switches to the disengaged state and maintaining the reliability of the variable valve structure. Furthermore, since the first and second intake cams do not need to move relative to the camshaft, they can be integrally formed with the camshaft. Furthermore, there is no need to machine complex, contoured surfaces on the camshaft to achieve intake valve lift switching. This avoids the difficulty of cutting and machining the camshaft due to complex shapes, thereby reducing the processing cost of the camshaft assembly.

[0008] In the variable valve structure of the above-mentioned engine, the sleeve portion has a mounting hole arranged along its axial direction, the outer wall of the linkage pin has a guide protrusion arranged along the circumferential direction and slidingly engaged with the inner wall of the mounting hole, and the second return spring is located in the mounting hole and is mounted on the linkage pin. The two ends of the second return spring respectively abut against the inner wall of the mounting hole and the guide protrusion. By providing the mounting hole in the sleeve portion, the linkage pin can be ensured to slide axially stably, thereby improving the stability and reliability of the variable valve structure. The two ends of the second return spring respectively abut against the guide protrusion and the inner wall of the mounting hole, so that the linkage pin can exit the pin hole under the action of the second return spring, and the intake rocker arm 1 and the intake rocker arm 2 can swing independently. The second return spring is located in the mounting hole and is mounted on the linkage pin, so that the second return spring has a better installation effect, so that the second return spring can stably and reliably drive the linkage pin to reset.

[0009] In the variable valve structure of the aforementioned engine, 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 sleeve portion further comprises a guide hole at the end proximal to the pin hole. The diameter of the guide hole is smaller than the diameter of the mounting hole, and the two are coaxially arranged. The front end of the linkage pin slides through the guide hole. The provision of the guide hole guides the front end of the linkage pin, further improving the movement stability of the linkage pin. When the motorcycle speed increases, the linkage pin can accurately and smoothly extend into the pin hole, thereby enhancing the reliability of the variable valve structure.

[0010] In the aforementioned variable valve structure for the engine, the mounting hole and the guide hole are transitionally connected by an annular step surface, with both ends of the second return spring respectively abutting against the annular step surface and the guide ridge. This design improves the installation of the second return spring, ensuring that the second return spring can stably and reliably drive the linkage pin to reset.

[0011] In the aforementioned variable valve structure for an engine, an annular groove is circumferentially arranged on the inner wall of the mounting hole at the end facing away from the guide hole. A retaining ring is embedded in the groove, and the guide protrusion is located inside the retaining ring and abuts against it. When the drive assembly releases the linkage pin, the linkage pin moves away from the first guide hole under the action of the second return spring. The retaining ring limits the linkage pin's travel, preventing it from falling out of the mounting hole and ensuring the reliability of the variable valve structure.

[0012] In the variable valve structure of the above-mentioned engine, the first intake rocker arm has a first rocker arm hole, the second intake rocker arm has a second rocker arm hole, and the rocker arm shaft passes through the first and second rocker arm holes, respectively. The first intake rocker arm has a first mating plane disposed around the first rocker arm hole on its end surface facing the second intake rocker arm, and the second intake rocker arm has a second mating plane disposed around the second rocker arm hole on its end surface facing the first intake rocker arm. The first mating plane and the second mating plane abut against each other. The first intake rocker arm and the second intake rocker arm are respectively sleeved onto the rocker arm shaft through the first and second rocker arm holes, thereby facilitating installation and ensuring stable installation of the first and second intake rocker arms. By setting the mating plane 1 and the mating plane 2 and making them abut each other, the operating accuracy of the intake rocker arm 1 and the intake rocker arm 2 can be improved, and the operating accuracy of the intake rocker arm 1 or the intake rocker arm 2 can be avoided, which may cause deviation in the installation position and reduction in the concentricity between the linkage pin and the pin hole, thereby avoiding the situation where the linkage pin is difficult to insert into the pin hole, thereby ensuring that the variable valve structure has high operating stability and reliability.

[0013] In the variable valve structure of the aforementioned engine, the cylinder block has mounting portions 1 and 2 arranged opposite each other. The ends of the rocker arm shaft are fixedly mounted on mounting portions 1 and 2, respectively. The side of the intake rocker arm 2 facing away from the intake rocker arm 1 has a cylindrical sleeve portion, and the return spring 1 is a torsion spring sleeved on the sleeve portion. A gasket is provided on the cylinder block. One end of the return spring 1 acts on the gasket, while the other end acts on the intake rocker arm 2, ensuring that the intake rocker arm 2 always rests against the outer circumference of the intake cam 2. Mounting portions 1 and 2 respectively support the ends of the rocker arm shaft, improving the stability of the rocker arm shaft installation. The sleeve portion provides a mounting location for the return spring 1, making its installation more stable. This effectively ensures that the intake rocker arm 2 always rests against the outer circumference of the intake cam 2, thereby improving the reliability of the variable valve structure.

[0014] In the aforementioned variable valve structure for an engine, the side of intake rocker arm 1 facing away from intake rocker arm 2 abuts against the side of mounting portion 1 facing mounting portion 2, and the end surface of the sleeve abuts against the side of mounting portion 2 facing mounting portion 1. Based on this design, since intake rocker arm 1 and intake rocker arm 2 abut against each other via mating plane 1 and mating plane 2, intake rocker arm 1 and intake rocker arm 2 are stably confined between mounting portion 1 and mounting portion 2, preventing axial movement of intake rocker arm 1 and intake rocker arm 2 during rotation, ensuring that they can effectively combine or independently swing, thereby improving the reliability of the variable valve structure.

[0015] In the variable valve structure for the aforementioned engine, the top of the intake rocker arm has an annular plug-in portion, the inner hole of which serves as the pin hole. The opposing end surfaces of the plug-in portion and the sleeve portion are both flat, and the plug-in portion and the sleeve portion are in close contact. This structure ensures that the plug-in portion and the sleeve portion are positioned close together, facilitating stable and smooth insertion and removal of the linkage pin into and out of the pin hole, thereby improving the operational stability and reliability of the variable valve structure.

[0016] In the variable valve structure of the aforementioned engine, the drive assembly includes a push rod slidably connected to the cylinder body and an electromagnet fixed to the outer wall of the cylinder body and having a push pin. The push rod is located between the linkage pin and the push pin, with one end of the push rod abutting the rear end of the linkage pin. The push pin of the electromagnet can push the other end of the push rod and drive the push rod axially. Electromagnets are existing technology and can be purchased directly on the market. When current passes through the electromagnet's coil, it generates a magnetic field, and the magnetic attraction or repulsion drives the drive shaft to extend and retract. Using an electromagnet to move the linkage pin has the advantages of high efficiency and good reliability.

[0017] Compared with the existing technology, the variable valve structure of this engine has the following advantages:

[0018] 1. This variable valve structure meets the design requirements for variable valve lift by adding a second intake rocker arm and providing a clutch assembly consisting of a drive assembly, a linkage pin, and return springs 1 and 2. The sleeve ensures stable movement of the linkage pin, and in conjunction with return spring 1, ensures that the second intake rocker arm always maintains a stable and reliable abutment against the second intake cam, enhancing operational stability and smooth clutch shifting. Furthermore, the presence of return spring 2 ensures accurate and timely reset of the linkage pin during low-speed operation, ensuring smooth clutch shifting to the disengaged state and guaranteeing the reliability of the variable valve structure.

[0019] 2. Since the intake cam 1 and the intake cam 2 are integrally formed on the camshaft, the intake cam 1 and the intake cam 2 can be processed and formed synchronously with the camshaft, and there is no need to process complex special-shaped surfaces on the camshaft surface to achieve the switching of the intake valve lift. Therefore, it can avoid the situation where the camshaft cutting and processing process is more difficult due to too complex shapes, thereby reducing the processing cost of the camshaft assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of a motorcycle engine.

[0021] Figure 2 It is a schematic diagram of the internal structure of the cylinder.

[0022] Figure 3 It is a structural schematic diagram of the variable valve structure.

[0023] Figure 4 It is a structural diagram of the camshaft, intake rocker arm 1, and intake rocker arm 2 in this variable valve structure.

[0024] Figure 5 This is a partial cross-sectional view of the variable valve structure when the intake rocker arm 1 and the intake rocker arm 2 swing independently.

[0025] Figure 6 This is a partial cross-sectional view of the variable valve structure when the intake rocker arm 1 and the intake rocker arm 2 are combined.

[0026] Figure 7 It is a side view of the camshaft.

[0027] Figure 8 The explosion of intake rocker arm 1, intake rocker arm 2, return spring 2 and linkage pin Figure 1 .

[0028] Figure 9 Explosion of intake rocker arm 1, intake rocker arm 2, return spring 2 and linkage pin Figure 2 .

[0029] In the figure, 1. cylinder block; 1a. mounting part 1; 1b. mounting part 2; 2. rocker arm shaft; 3. camshaft; 31. intake cam 1; 32. intake cam 2; 33. exhaust cam; 4. intake valve; 5. intake rocker arm 1; 51. plug-in part; 511. pin hole; 52. rocker arm hole 1; 53. mating plane 1; 6. intake rocker arm 2; 61. sleeve part; 611. mounting hole; 612. guide hole; 613. annular step surface; 614. annular groove; 62. rocker arm hole 2; 63. mating plane 2; 64. sleeve part; 7. return spring 1; 8. linkage pin; 81. guide cam; 9. drive assembly; 91. push rod; 92. electromagnet; 921. ejector pin; 10. return spring 2; 11. gasket; 12. retaining ring. DETAILED DESCRIPTION

[0030] The following is a specific embodiment of the present invention and combined with the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to this embodiment.

[0031] like Figures 1 to 3 As shown, in the variable valve structure of the engine, the engine includes a cylinder block 1, a rocker arm shaft 2 and a camshaft 3 are provided in the cylinder block 1, and an intake cam 1 31, an intake cam 2 32 and an exhaust cam 33 are integrally formed on the camshaft 3. Figure 7 As shown, the lobe tip of the intake cam 2 32 is opposite to and higher than the lobe tip of the intake cam 1 31. The variable valve structure includes an intake rocker arm 1 5 and an intake rocker arm 2 6 arranged on the rocker arm shaft 2. The intake rocker arm 1 5 is against the outer peripheral surface of the intake cam 1 31 and can drive the intake valve 4 to open and close.

[0032] like Figure 4 、 Figure 5 and Figure 6 As shown, a return spring 7 is provided in the cylinder body 1 , and under the action of the return spring 7 , the intake rocker arm 6 can always rest against the outer peripheral surface of the intake cam 32 .

[0033] like Figures 3 to 6 As shown, the top of the intake rocker arm 2 6 has a cylindrical sleeve portion 61, and a linkage pin 8 parallel to the rocker arm shaft 2 is slidably arranged in the sleeve portion 61. The top of the intake rocker arm 1 5 is provided with a pin hole 511 matching the outer diameter of the linkage pin 8. The cylinder body 1 is provided with a driving component 9 that can push the linkage pin 8 to move so that one end of the linkage pin 8 extends into the pin hole 511. The variable valve structure also includes a return spring 2 10 that can drive the linkage pin 8 to move away from the pin hole 511 and disengage from the pin hole 511.

[0034] like Figure 6 、 Figure 8 and Figure 9As shown, the sleeve portion 61 has a mounting hole 611 disposed axially therein. The outer wall of the linkage pin 8 has a circumferentially disposed guide protrusion 81 that slidably engages the inner wall of the mounting hole 611. The second return spring 10 is positioned within the mounting hole 611 and sleeved onto the linkage pin 8. The ends of the second return spring 10 respectively abut against the inner wall of the mounting hole 611 and the guide protrusion 81. The end of the linkage pin 8 that can extend into the pin hole 511 is the front end, while the other end is the rear end. The sleeve portion 61 also has a guide hole 612 at the end proximal to the pin hole 511. The diameter of the guide hole 612 is smaller than that of the mounting hole 611, and the two are coaxially disposed. The front end of the linkage pin 8 slides through the guide hole 612. An annular step surface 613 transitions between the mounting hole 611 and the guide hole 612. The ends of the second return spring 10 respectively abut against the annular step surface 613 and the guide protrusion 81. An annular groove 614 is circumferentially arranged on the inner wall of the mounting hole 611 at the end facing away from the guide hole 612. A retaining ring 12 is embedded in the annular groove 614. The guide protrusion 81 is located inside the retaining ring 12 and can abut against it. When the drive assembly 9 releases the linkage pin 8, the linkage pin 8 moves away from the guide hole 612 under the action of the return spring 10. The retaining ring 12 then limits the travel of the linkage pin 8, preventing it from falling out of the mounting hole 611 and ensuring the reliability of the variable valve structure.

[0035] like Figure 5 、 Figure 8 and Figure 9 As shown, the intake rocker arm 1 5 has a rocker arm hole 1 52, the intake rocker arm 2 6 has a rocker arm hole 2 62, the rocker arm shaft 2 passes through the rocker arm hole 1 52 and the rocker arm hole 2 62 respectively, the end surface of the intake rocker arm 1 5 facing the intake rocker arm 2 6 has a matching plane 1 53 arranged around the rocker arm hole 1 52, and the end surface of the intake rocker arm 2 6 facing the intake rocker arm 1 5 has a matching plane 2 63 arranged around the rocker arm hole 2 62, and the matching plane 1 53 and the matching plane 2 63 are in contact with each other.

[0036] like Figure 2 As shown, the cylinder body 1 has a mounting portion 1a and a mounting portion 1b that are arranged opposite to each other, and both ends of the rocker arm shaft 2 are fixedly installed on the mounting portion 1a and the mounting portion 1b, respectively. Figure 4 and Figure 5 As shown, the side of intake rocker arm 2 (6) facing away from intake rocker arm 1 (5) has a cylindrical sleeve portion 64. Return spring 1 (7) is a torsion spring that sleeves onto sleeve portion 64. A gasket 11 is provided on cylinder block 1. One end of return spring 1 (7) acts on gasket 11, while the other end acts on intake rocker arm 2 (6), ensuring that intake rocker arm 2 (6) always rests against the outer circumference of intake cam 2 (32). The side of intake rocker arm 1 (5) facing away from intake rocker arm 2 (6) abuts against the side of mounting portion 1 (1a) facing mounting portion 2 (1b). The end face of sleeve portion 64 abuts against the side of mounting portion 2 (1b) facing mounting portion 1 (1a).

[0037] like Figure 6 、 Figure 8 and Figure 9 As shown, in the variable valve structure of the above-mentioned engine, the top of the intake rocker arm 5 has a circular plug-in portion 51, the inner hole of the plug-in portion 51 is a pin hole 511, and the opposite end faces of the plug-in portion 51 and the sleeve portion 61 are both flat, and the plug-in portion 51 and the sleeve portion 61 are in contact with each other.

[0038] like Figure 5 、 Figure 6 As shown, the drive assembly 9 includes a push rod 91 slidingly connected to the cylinder body 1 and an electromagnet 92 fixed to the cylinder body 1 and having a ejector pin 921. The electromagnet 92 is located on the side of the linkage pin 8 facing away from the intake rocker arm 5. The push rod 91 is located between the linkage pin 8 and the ejector pin 921. One end face of the push rod 91 abuts against the end face of the linkage pin 8. The ejector pin 921 of the electromagnet 92 can push the other end of the push rod 91 and drive the push rod 91 to move axially.

[0039] The following describes the working principle of the variable valve structure of this engine:

[0040] like Figure 5 As shown, when the motorcycle is traveling at low speed and the engine is at low rpm, linkage pin 8 is released from pin hole 511 by return spring 2 10. Intake rocker arm 1 5 and intake rocker arm 2 6 then swing independently. The lift of intake valve 4 is controlled by intake rocker arm 1 5, while intake rocker arm 2 6 does not abut against intake valve 4, so its movement does not affect the lift of intake valve 4. Because the lobe of intake cam 1 31 is relatively low, the lift of intake valve 4 is relatively small during this process, resulting in a smaller intake volume.

[0041] like Figure 6 As shown, when the motorcycle is running at high speed and the engine is at high speed, the driving component 9 pushes the linkage pin 8. When the linkage pin 8 is opposite to the pin hole 511, the linkage pin 8 can be extended into the pin hole 511, and the linkage pin 8 is still maintained in the pin hole 511 by the pushing force of the driving component 9. At this time, the intake rocker arm 1 5 and the intake rocker arm 2 6 are combined, so that the intake rocker arm 2 6 swings with the intake rocker arm 1 5 with the same swing amplitude. At this time, since the intake rocker arm 2 6 is against the outer peripheral surface of the intake cam 2 32 and the lobe tip of the intake cam 2 32 is higher than the lobe tip of the intake cam 1 31, the swing amplitude of the intake rocker arm 1 5 is increased to the same as the swing amplitude of the intake rocker arm 2 6, thereby increasing the lift of the intake valve 4 and the intake amount, ensuring more complete engine combustion, reducing emissions, and optimizing engine performance.

[0042] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope defined by the appended claims.

[0043] Although this article uses the terms 1. cylinder block; 1a. mounting part one; 1b. mounting part two; 2. rocker arm shaft; 3. camshaft; 31. intake cam one; 32. intake cam two; 33. exhaust cam; 4. intake valve; 5. intake rocker arm one; 51. plug-in part; 511. pin hole; 52. rocker arm hole one; 53. matching plane one; 6. intake rocker arm two; 61. sleeve part; 611. mounting hole; 612. guide hole; 613. annular step surface; 614. annular groove; 62. rocker arm hole two; 63. matching plane two; 64. sleeve part; 7. return spring one; 8. linkage pin; 81. guide ridge; 9. drive assembly; 91. push rod; 92. electromagnet; 921. ejector pin; 10. return spring two; 11. gasket; 12. retaining ring, etc., the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitations is contrary to the spirit of the present invention.

Claims

1. A variable valve structure of an engine, the engine comprising a cylinder block (1) and an intake valve (4), wherein a rocker arm shaft (2) and a camshaft (3) are provided in the cylinder block (1), characterized in that: The camshaft (3) is provided with an intake cam 1 (31) and an intake cam 2 (32), the lobe tip of the intake cam 2 (32) is higher than the lobe tip of the intake cam 1 (31), the variable valve structure comprises an intake rocker arm 1 (5) and an intake rocker arm 2 (6) arranged on the rocker arm shaft (2), the intake rocker arm 1 (5) abuts against the outer peripheral surface of the intake cam 1 (31) and can drive the intake valve (4) to open and close, and a return spring 1 (7) is provided in the cylinder body (1), and under the action of the return spring 1 (7), the intake rocker arm 2 (6) can always abut against the intake cam 2 (3 2), the top of the intake rocker arm 2 (6) has a cylindrical sleeve portion (61), a linkage pin (8) parallel to the rocker arm shaft (2) is slidably provided in the sleeve portion (61), the top of the intake rocker arm 1 (5) is provided with a pin hole (511) matching the outer diameter of the linkage pin (8), the cylinder body (1) is provided with a driving component (9) capable of pushing the linkage pin (8) to move and allowing one end of the linkage pin (8) to extend into the pin hole (511), and the variable valve structure also includes a return spring 2 (10) capable of driving the linkage pin (8) to move and escape from the pin hole (511).

2. The variable valve structure of the engine according to claim 1, characterized in that: The sleeve portion (61) has a mounting hole (611) arranged along its axial direction, and the outer wall of the linkage pin (8) has a guide protrusion (81) arranged along the circumferential direction and slidingly matched with the inner wall of the mounting hole (611). The second reset spring (10) is located in the mounting hole (611) and is sleeved on the linkage pin (8), and the two ends of the second reset spring (10) respectively abut against the inner wall of the mounting hole (611) and the guide protrusion (81).

3. The variable valve structure of the engine according to claim 2, characterized in that: The end of the linkage pin (8) that can be inserted into the pin hole (511) is the front end, and the other end is the rear end. The end of the sleeve portion (61) close to the pin hole (511) also has a guide hole (612). The diameter of the guide hole (612) is smaller than the diameter of the mounting hole (611), and the two are coaxially arranged. The front end of the linkage pin (8) is slidably inserted into the guide hole (612).

4. The variable valve structure of the engine according to claim 3, characterized in that: The mounting hole (611) and the guide hole (612) are transitionally connected via an annular step surface (613), and the two ends of the second reset spring (10) respectively abut against the annular step surface (613) and the guide convex edge (81).

5. The variable valve structure of an engine according to claim 3 or 4, characterized in that: An annular groove (614) is provided on the inner wall of one end of the mounting hole (611) facing away from the guide hole (612) along the circumferential direction. A retaining ring (12) is embedded in the annular groove (614). The guide protrusion (81) is located on the inner side of the retaining ring (12) and can abut against the retaining ring (12).

6. The variable valve structure of an engine according to claim 1, 2, 3 or 4, characterized in that: The intake rocker arm 1 (5) has a rocker arm hole 1 (52), the intake rocker arm 2 (6) has a rocker arm hole 2 (62), the rocker arm shaft (2) passes through the rocker arm hole 1 (52) and the rocker arm hole 2 (62) respectively, the intake rocker arm 1 (5) has a matching plane 1 (53) arranged around the rocker arm hole 1 (52) on the end surface facing the intake rocker arm 2 (6), and the intake rocker arm 2 (6) has a matching plane 2 (63) arranged around the rocker arm hole 2 (62) on the end surface facing the intake rocker arm 1 (5), and the matching plane 1 (53) and the matching plane 2 (63) are in contact with each other.

7. The variable valve structure of an engine according to claim 1, 2, 3 or 4, characterized in that: The cylinder body (1) has a mounting portion 1 (1a) and a mounting portion 2 (1b) that are arranged opposite to each other. The two ends of the rocker arm shaft (2) are fixedly mounted on the mounting portion 1 (1a) and the mounting portion 2 (1b) respectively. The intake rocker arm 2 (6) has a cylindrical sleeve portion (64) on the side facing away from the intake rocker arm 1 (5). The return spring 1 (7) is a torsion spring sleeved on the sleeve portion (64).

8. The variable valve structure of the engine according to claim 7, characterized in that: The side surface of the intake rocker arm 1 (5) facing away from the intake rocker arm 2 (6) is in contact with the side surface of the mounting portion 1 (1a) facing the mounting portion 2 (1b), and the end surface of the sleeve portion (64) is in contact with the side surface of the mounting portion 2 (1b) facing the mounting portion 1 (1a).

9. The variable valve structure of an engine according to claim 1, 2, 3 or 4, characterized in that: The top of the intake rocker arm (5) has a circular plug-in portion (51), the inner hole of the plug-in portion (51) is the pin hole (511), the opposite end faces of the plug-in portion (51) and the sleeve portion (61) are both planes, and the plug-in portion (51) and the sleeve portion (61) are in contact with each other.

10. The variable valve structure of an engine according to claim 1, 2, 3 or 4, characterized in that: The driving assembly (9) comprises a push rod (91) slidably connected to the cylinder body (1) and an electromagnet (92) fixed to the outer wall of the cylinder body (1) and having a push pin (921). The push rod (91) is located between the linkage pin (8) and the push pin (921). One end face of the push rod (91) abuts against the rear end face of the linkage pin (8). The push pin (921) of the electromagnet (92) can push the other end of the push rod (91) and drive the push rod (91) to move axially.

Images