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 problem that in the prior art, a variable valve structure is insufficient in reliability is solved. The variable valve structure of the engine comprises a first air inlet rocker arm and a second air inlet rocker arm which are arranged on a rocker arm shaft, a first air inlet cam and a second air inlet cam are arranged on a cam shaft, the first air inlet rocker arm abuts against the peripheral face of the first air inlet cam in a matched mode and can drive an air inlet valve to be opened and closed, and a linkage pin parallel to the rocker arm shaft is arranged on the first air inlet rocker arm in a penetrating mode. The linkage pin is located on the side, close to the air inlet valve, of the rocker arm shaft and is higher than the rocker arm shaft, the second air inlet rocker arm abuts against the peripheral face of the second air inlet cam in a matched mode, and a pin hole parallel to the linkage pin and matched with the linkage pin in outer diameter is formed in the second air inlet rocker arm. The driving assembly is located on the outer side of the linkage pin in the axis direction and can push the linkage pin to enable the linkage pin to partially stretch into the pin hole. The utility model has the advantages of compact structure and high reliability.

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 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 part and a lobe part. The base circle part refers to the cylindrical part of the outer wheel surface on the cam, and the lobe part is the part of the cam that protrudes from the base circle part. That is, when the rocker arm abuts against the base circle part, the valve is in a closed state, and when the lobe part abuts against 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 volume increases. The engine with fixed valve lift will cause incomplete gas combustion, affecting emissions and fuel economy.

[0003] In view of the existence of the above problems, a variable valve structure is derived on the engine. Since the lift size of the intake valve is determined by the profile of the cam on the camshaft, the conventional variable valve structure on the motorcycle generally adopts two intake cams with different profiles or an intake cam with a changeable profile. The intake cams with two different profiles are switched to contact the intake rocker arm respectively, or the profile of the intake cam is changed to contact the intake rocker arm, so as to change the action posture of the intake rocker arm and thus change the intake volume. For example, a variable valve lift device for a motorcycle tappet engine disclosed in the patent document (application number: 201620498502.6) is disclosed. In the device, when the motorcycle engine is running at high speed, the high-speed cam slider overcomes the action force of the slider positioning spring, the high-speed cam slider deflects upward, the centrifugal block overcomes the action force of the centrifugal block spring to rotate to a certain extent and drives the high-speed rotating shaft to rotate, and then the high-speed rotating shaft is used to push the high-speed cam slider to deflect upward. At this time, the high-speed cam slider drives the rocker arm to rotate, so that the exhaust valve and the intake valve can be lifted. The variable valve structure has some shortcomings in actual use: the radial displacement of the high-speed cam slider is affected by the centrifugal force and the slider positioning spring and the centrifugal block spring. However, due to the extended use time or other factors, the preload force of the spring may change and the elasticity of the spring may become unstable. If the preload 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 fail to reset into place and protrude from the low-speed cam surface after reset, resulting in abnormal valve lift and affecting the reliability of the variable valve structure. 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 of an engine. The technical problem solved by the utility model is: how to improve the reliability of the variable valve structure and make the engine structure compact at the same time.

[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 head and a cylinder cover, a rocker shaft, a camshaft and an intake valve are arranged in the cylinder head, and the variable valve structure includes an intake rocker arm 1 and an intake rocker arm 2 arranged on the rocker shaft, 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 intake rocker arm 1 is abutted against the outer peripheral surface of the intake cam 1 and can drive the intake valve to open and close, the intake rocker arm 1 is penetrated with a linkage pin parallel to the rocker shaft, the linkage pin is located on the side of the rocker shaft close to the intake valve and is higher than the rocker shaft, the intake rocker arm 2 is abutted against the outer peripheral surface of the intake cam 2, the intake rocker arm 2 is provided with a pin hole parallel to the linkage pin and matching the outer diameter of the linkage pin, and the cylinder cover is provided with a driving component, the driving component is located on the outside of the linkage pin axis direction and can push the linkage pin so that the linkage pin part extends into the pin hole.

[0006] When the motorcycle is running at low speed and the engine is at low speed, the linkage pin is not inserted into the pin hole, so that the intake rocker arm 1 and the intake rocker arm 2 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 tip of the intake cam 1 is lower, the lift of the intake valve is smaller in this process, and the intake volume is smaller. When the motorcycle is running at high speed and the engine is at high speed, the driving assembly pushes the linkage pin, and when the linkage pin is facing the pin hole, the linkage pin part extends into the pin hole, so that the intake rocker arm 1 and the intake rocker arm 2 are combined. At this time, since the pin hole matches the outer diameter of the linkage pin, the intake rocker arm 2 will swing with the intake rocker arm 1 at the same amplitude. Since the intake rocker arm 2 abuts against the outer peripheral surface of the intake cam 2 and the lobe of the intake cam 2 is higher than the lobe 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] In this design, since the intake cam 1 and the intake cam 2 are directly processed and formed on the camshaft, this structure makes it easy to process the intake cam 1 and the intake cam 2, such as directly forming them in one piece, thereby ensuring the processing accuracy of the intake cam 1 and the intake cam 2, thereby improving the operating stability of the variable valve structure. Moreover, in this solution, the positions of the intake cam 1 and the intake cam 2 will not change relative to the camshaft, and even if the motorcycle is used for a long time, the change range of the valve lift can always remain consistent, and there will be no abnormal intake valve lift due to the failure of the high-speed cam slider to reset after a long time of use, as in the patent "A variable valve lift device for a motorcycle tappet engine (application number: 201620498502.6)" in the background technology. Therefore, the variable valve structure has good reliability and working stability.

[0008] In addition, in this solution, the structure of the linkage pin and the pin hole occupies a small space in the cylinder head, which is conducive to the compact design of the cylinder head and reduces the size of the cylinder head. At the same time, because the linkage pin is located on the side of the rocker shaft close to the intake valve and is higher than the rocker shaft, that is, the linkage pin is located obliquely above the rocker shaft but not directly above it, on the basis of a certain distance between the linkage pin and the rocker shaft, the height position of the linkage pin relative to the cylinder head can be reduced, so that the installation height of the drive assembly located outside the axis direction of the linkage pin can also be reduced, so that the height size of the engine can be further reduced, achieving a compact structure.

[0009] In the variable valve structure of the above-mentioned engine, the cylinder head has two plate-shaped supporting parts that are arranged opposite to each other, and the two ends of the rocker arm shaft are respectively fixed and penetrated on the two supporting parts. The inner wall of the cylinder head has a mounting protrusion for installing the drive assembly, and a step for avoiding the mounting protrusion is provided on the supporting part close to the drive assembly. The two supporting parts support the two ends of the rocker arm shaft respectively, which can improve the installation stability of the rocker arm shaft. By providing the mounting protrusion, the installation of the drive assembly can be facilitated, and by providing the step for avoiding the mounting protrusion on the supporting part, the position of the mounting protrusion can be lowered, that is, the installation height of the drive assembly can also be lowered, thereby reducing the height size of the engine and achieving a compact structure.

[0010] In the variable valve structure of the engine described above, the step is provided with a mounting hole 1 penetrating through the bottom surface of the cylinder head, and a fastener for fixing the cylinder head to the cylinder body of the engine is inserted into the mounting hole 1. By providing the step, the mounting surface of the fastener can be lowered, and thus the mounting height of the drive assembly can also be lowered. The fastener is provided on the step of the support part, so that the support part can be used to support the rocker shaft, and can also be used for the fastener to pass through, and then the cylinder head and the cylinder body can be fixedly connected by the fastener, that is, the purpose of one object for multiple uses is achieved through the support part, so that the cylinder head structure can be simplified and the structure can be compact.

[0011] In the variable valve structure of the above-mentioned engine, the two support parts are provided with a clearance step, and the clearance steps on the two support parts are both located on the side of the support part close to the intake valve, and the top surface of the two support parts away from the intake valve is provided with mounting holes 2 respectively, the upper port of the mounting hole 1 is lower than the upper port of the mounting hole 2, and the mounting holes 1 and 2 are both penetrated with fasteners for fixing the cylinder head to the cylinder body of the engine. The two support parts are provided with a clearance step, so that the two support parts form a symmetrical structure, which is convenient for processing. By respectively arranging mounting hole 1 and mounting hole 2 on the support parts, there are multiple fasteners for connecting the cylinder head and the cylinder body, so that the connection between the cylinder head and the cylinder body is more stable. The upper port of mounting hole 1 is lower than the upper port of mounting hole 2, so that the height of the drive component located above mounting hole 1 can be reduced, thereby reducing the height size of the engine.

[0012] In the variable valve structure of the above-mentioned engine, the intake rocker arm 2 is located on the side of the intake rocker arm 1 facing away from the drive assembly, and the intake rocker arm 2 has a cylindrical sleeve portion sleeved on the rocker arm shaft on the side facing away from the intake rocker arm, and the sleeve portion is sleeved with a torsion spring that enables the intake rocker arm 2 to always abut against the outer peripheral surface of the intake cam 2. This design enables the rocker arm shaft to be provided with a torsion spring, the intake rocker arm 2 and the intake rocker arm 1 in sequence in the direction close to the drive assembly, so that the distance between the intake rocker arm 1 and the linkage pin on the intake rocker arm 1 and the drive assembly is relatively close, so that the length required for the push rod is relatively short, and the required installation space is also relatively small, so that the effect of compact structure can be achieved. By providing the sleeve portion on the intake rocker arm 2, the sleeve portion provides a mounting position for the torsion spring, so that the installation of the torsion spring is more stable. The torsion spring can enable the intake rocker arm 2 to always stably and reliably abut against the outer peripheral surface of the intake cam 2, thereby improving the stability of the operation of the device.

[0013] In the variable valve structure of the above-mentioned engine, the top of the intake rocker arm 1 has a cylindrical sleeve portion, the intake rocker arm 2 has an extension portion extending upwardly obliquely relative to the sleeve portion, the pin hole is opened on the extension portion, the linkage pin is slidably penetrated in the sleeve portion, and the sleeve portion is also provided with a reset spring that can drive the linkage pin to move and escape from the pin hole. Since the linkage pin is located obliquely above the rocker arm shaft, at this time, the extension portion extending obliquely upward is provided on the intake rocker arm 2, so that the pin hole on the extension portion can be directly opposite to the linkage pin, so as to achieve the purpose of lowering the height position of the linkage pin, and finally the installation height of the drive assembly can also be reduced. When the engine speed decreases, the drive assembly retracts to release the linkage pin, and the linkage pin escapes from the pin hole under the action of the reset spring. At this time, the intake rocker arm 1 and the intake rocker arm 2 swing independently, the lift of the intake valve is reduced, and the intake volume is reduced. Using the reset spring to achieve the reset of the linkage pin has the advantages of good reliability and low cost.

[0014] In the variable valve structure of the above-mentioned engine, the intake rocker arm 1 and the intake rocker arm 2 are in contact with each other, and the side of the intake rocker arm 1 facing away from the intake rocker arm 2 is in contact with the support portion closer to the drive assembly. After the intake rocker arm 1 and the intake rocker arm 2 are in contact with each other, an axial limit is formed with each other, which can improve the swing smoothness of the intake rocker arm 1 and the intake rocker arm 2, avoid the situation where the swing smoothness of the intake rocker arm 1 or the intake rocker arm 2 is reduced and causes the deviation of the installation position, and further avoid the situation where the linkage pin is difficult to extend into the pin hole, thereby ensuring that the variable valve structure has high operating stability and reliability. The side of the intake rocker arm 1 facing away from the intake rocker arm 2 is in contact with the support portion closer to the drive assembly, so that the distance between the intake cam 1 and the linkage pin on the intake cam 1 and the drive assembly is closer, so that the length required for the push rod is shorter and the installation space required for the push rod is smaller, so that the effect of compact structure can be achieved.

[0015] In the variable valve structure of the above-mentioned engine, the mounting protrusion has a plug hole and a guide hole located inside the plug hole and coaxial with the plug hole. The driving assembly includes a push rod slidably inserted into the guide hole and an electromagnet inserted and positioned in the plug hole. The electromagnet moves by pushing the linkage pin against the push rod. By setting the guide hole, the installation of the push rod is realized and a guide is formed for its axial movement, thereby ensuring that the electromagnet can drive the push rod to move stably. Using an electromagnet to move the linkage pin has the advantages of high efficiency and good reliability.

[0016] In the variable valve structure of the above-mentioned engine, the electromagnet includes a shell with an end portion and a pin that can be axially extended and retracted relative to the shell. The end portion of the electromagnet is plugged and fixed in the plug hole, and the pin of the electromagnet can push the push rod to move axially. The electromagnet is a prior art and can be directly purchased on the market. It generates a magnetic field when current passes through the coil of the electromagnet, and drives the extension and retraction of the pin through the attraction or repulsion of the magnetic force. The electromagnet is fixedly connected to the outer wall of the box cover by bolts, and at the same time, the end portion of the electromagnet shell is plugged and fixed in the plug hole, which can further improve the installation stability of the electromagnet and prevent the electromagnet from loosening, so that the electromagnet can stably push the push rod to move, thereby improving the working reliability of the drive component.

[0017] In the variable valve structure of the above-mentioned engine, an oil seal is sleeved on the push rod, and the oil seal is sealed with the inner wall of the plug hole, the guide hole is concentrically arranged with the plug hole, and the diameter of the plug hole is larger than the diameter of the guide hole. In order to ensure that the push rod can move smoothly, a lubricating substance such as grease is applied to the push rod. At this time, by setting an oil seal in the plug hole, the pollution of the grease by the external environment can be isolated and the leakage of grease can be avoided, thereby ensuring that the push rod can always move axially stably and accurately, and improving the working reliability of the drive assembly. The larger diameter of the plug hole can facilitate the plug-in fixation of the electromagnet, making the installation of the electromagnet easier.

[0018] Compared with the prior art, the variable valve structure of this engine has the following advantages:

[0019] 1. In this variable valve structure, the intake cam 1 and the intake cam 2 are directly processed and formed on the camshaft. During the running of the motorcycle, the positions of the intake cam 1 and the intake cam 2 will not change relative to the camshaft. Therefore, this variable valve structure has good reliability and working stability.

[0020] 2. A step is provided on the support portion to avoid the installation protrusion, so that the position of the installation protrusion can be lowered, that is, the installation height of the drive component can also be lowered, thereby reducing the height size of the engine and achieving a compact structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a three-dimensional structural diagram of the cylinder head and cylinder cover of this engine.

[0022] Figure 2 It is a three-dimensional structural diagram of the variable valve structure.

[0023] Figure 3 It is a structural schematic diagram of intake rocker arm 1, intake rocker arm 2, rocker arm shaft and camshaft in the variable valve structure.

[0024] Figure 4It is a partial schematic diagram of the variable valve structure.

[0025] Figure 5 It is a front view of the camshaft in this variable valve structure.

[0026] Figure 6 It is a cross-sectional view of the variable valve structure.

[0027] Figure 7 It is a structural schematic diagram of the cylinder head in the variable valve structure.

[0028] Figure 8 It is a structural schematic diagram of the cylinder head in the variable valve structure.

[0029] Fig. 9 It is a structural schematic diagram of the intake rocker arm 2 in the variable valve structure.

[0030] Fig.10 This variable valve structure Figure 6 Enlarged view of point A in the middle.

[0031] Fig.11 It is a partial cross-sectional view when the linkage pin part extends into the pin hole to combine the intake rocker arm 1 and the intake rocker arm 2.

[0032] In the figure, 1, cylinder head; 1a, mounting convex part; 1a1, plug-in hole; 1a2, guide hole; 2, cylinder head; 21, support part; 211, give way step; 3, rocker shaft; 4, camshaft; 41, intake cam one; 42, intake cam two; 43, exhaust cam; 44, lobe; 5, intake valve; 6, exhaust rocker; 7, intake rocker one; 71, sleeve part; 8, intake rocker two; 81, extension part; 82, sleeve part; 9, drive assembly; 91, push rod; 92, electromagnet; 921, end head; 922, ejector pin; 10, pin hole; 11, linkage pin; 12, mounting hole one; 13, fastener; 14, mounting hole two; 15, torsion spring; 16, return spring; 17, oil seal. DETAILED DESCRIPTION

[0033] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0034] Embodiment 1

[0035] like Figure 1 and Figure 2 As shown, the engine includes a cylinder block, a cylinder head 2 and a cylinder cover 1 arranged in sequence from bottom to top. The cylinder block is a prior art and is not shown in the figure. A rocker arm shaft 3, a camshaft 4, an intake valve 5 and an exhaust rocker arm 6 are arranged in the cylinder head 2. The variable valve structure of the engine includes an intake rocker arm 1 7 and an intake rocker arm 2 8 arranged on the rocker arm shaft 3.

[0036] like Figures 2 to 5 As shown, the camshaft 4 has an intake cam 1 41, an intake cam 2 42 and an exhaust cam 43, the lobe 44 of the intake cam 2 42 is higher than the lobe 44 of the intake cam 1 41, the intake rocker arm 7 is in abutment with the outer peripheral surface of the intake cam 41 and can drive the intake valve 5 to open and close, the intake rocker arm 7 is provided with a linkage pin 11 parallel to the rocker shaft 3, the linkage pin 11 is located on the side of the rocker shaft 3 close to the intake valve 5 and is higher than the rocker shaft 3, the intake rocker arm 2 8 is in abutment with the outer peripheral surface of the intake cam 2 42, the intake rocker arm 2 8 is provided with a pin hole 10 parallel to the linkage pin 11 and matching the outer diameter of the linkage pin 11, the cylinder head 1 is provided with a driving component 9, the driving component 9 is located on the outside of the linkage pin 11 in the axial direction and can push the linkage pin 11 so that the linkage pin 11 partially extends into the pin hole 10.

[0037] like Figures 2 to 5 As shown, the intake rocker arm 2 8 is located on the side of the intake rocker arm 1 7 facing away from the drive assembly 9, as shown in FIG. Figure 8 As shown, the intake rocker arm 2 8 has a cylindrical sleeve portion 82 sleeved on the rocker arm shaft 3 on the side facing away from the intake rocker arm 1 7, and the sleeve portion 82 is sleeved with a torsion spring 15 that enables the intake rocker arm 2 8 to always abut against the outer peripheral surface of the intake cam 2 42. The top of the intake rocker arm 1 7 has a cylindrical sleeve abutting cylinder portion 71, and the intake rocker arm 2 8 has an extension portion 81 that extends upwardly and obliquely relative to the sleeve portion 82, and the pin hole 10 is opened on the extension portion 81, and the linkage pin 11 is slidably penetrated in the sleeve portion 71, and the sleeve portion 71 is also provided with a return spring 16 that can drive the linkage pin 11 to move and escape from the pin hole 10.

[0038] like Figure 6 , Figure 7 and Figure 8 As shown, the cylinder head 2 has two plate-shaped support parts 21 arranged opposite to each other, and the two ends of the rocker arm shaft 3 are respectively fixedly penetrated on the two support parts 21. The two support parts 21 respectively support the two ends of the rocker arm shaft 3, which can improve the installation stability of the rocker arm shaft 3. Figure 8 As shown, the inner wall of the cylinder head 1 is provided with a mounting protrusion 1a for mounting the drive assembly 9. The mounting protrusion 1a is provided to facilitate the installation of the drive assembly 9. A clearance step 211 is provided on the support portion 21 close to the drive assembly 9 to avoid the mounting protrusion 1a. The clearance step 211 is provided with a mounting hole 12 penetrating the bottom surface of the cylinder head 2. A fastener 13 is provided in the mounting hole 12 to securely connect the cylinder head 2 to the cylinder block of the engine.

[0039] Further, such as Figure 7As shown, the two support parts 21 are provided with a clearance step 211, and the clearance steps 211 on the two support parts 21 are both located on the side of the support part 21 close to the intake valve 5, and the top surfaces of the two support parts 21 away from the intake valve 5 are respectively provided with mounting holes 14, and the mounting holes 12 and 14 are both penetrated with fasteners 13 for fixing the cylinder head 2 to the cylinder body of the engine, and the upper end of the mounting hole 12 is lower than the upper end of the mounting hole 14. By respectively providing the mounting holes 12 and 14 on the support part 21, the cylinder head 2 and the cylinder body are connected by multiple fasteners 13, so that the connection between the cylinder head 2 and the cylinder body is more stable.

[0040] Such as 10 and Fig.11 As shown, the intake rocker arm 1 7 and the intake rocker arm 2 8 are in close contact with each other, and the side of the intake rocker arm 1 7 facing away from the intake rocker arm 2 8 is in close contact with the support portion 21 close to the drive assembly 9. After the intake rocker arm 1 7 and the intake rocker arm 2 8 are in close contact with each other, an axial limit is formed between them, which can improve the swing smoothness of the intake rocker arm 1 7 and the intake rocker arm 2 8, thereby ensuring that the variable valve structure has high operating stability and reliability.

[0041] Such as 10 and Fig.11 As shown, the mounting protrusion 1a has a plug hole 1a1 and a guide hole 1a2 located inside the plug hole 1a1 and coaxial with the plug hole 1a1. The driving assembly 9 includes a push rod 91 slidably inserted into the guide hole 1a2 and an electromagnet 92 inserted and positioned in the plug hole 1a1. The electromagnet 92 moves by pushing the linkage pin 11 through the push rod 91. The electromagnet 92 includes a housing with an end portion 921 and a push pin 922 that can axially extend and retract relative to the housing. The end portion 921 of the electromagnet 92 is inserted and fixed in the plug hole 1a1, and the push pin 922 of the electromagnet 92 can push the push rod 91 to move axially. The push rod 91 is sleeved with an oil seal 17, which is sealed with the inner wall of the plug hole 1a1. The guide hole 1a2 is concentrically arranged with the plug hole 1a1, and the diameter of the plug hole 1a1 is larger than the diameter of the guide hole 1a2. The electromagnet 92 is a prior art and can be directly purchased on the market. When current passes through the coil of the electromagnet 92 , a magnetic field is generated, and the extension and retraction of the ejector pin 922 are driven by the attraction or repulsion of the magnetic force.

[0042] The following describes the working principle of the variable valve structure:

[0043] like Fig.10As shown, when the motorcycle is running at a low speed and the engine is at a low speed, the linkage pin 11 is in a position where it does not extend into the pin hole 10, so that the intake rocker arm 1 7 and the intake rocker arm 2 8 swing independently. At this time, the lift of the intake valve 5 is controlled by the intake rocker arm 1 7, and the intake rocker arm 2 8 does not abut against the intake valve 5, so its movement does not affect the lift of the intake valve 5. Since the lobe 44 of the intake cam 1 41 is relatively low, the lift of the intake valve 5 is relatively small during this process, and the intake volume is relatively small.

[0044] like Fig.11 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 11. When the linkage pin 11 is opposite to the pin hole 10, the linkage pin 11 partially extends into the pin hole 10, so that the intake rocker arm 1 7 and the intake rocker arm 2 8 are combined. At this time, since the outer diameter of the pin hole 10 matches the outer diameter of the linkage pin 11, the intake rocker arm 2 8 will swing with the intake rocker arm 1 7 at the same amplitude. Since the intake rocker arm 2 8 abuts against the outer peripheral surface of the intake cam 2 42 and the lobe portion 44 of the intake cam 2 42 is higher than the lobe portion 44 of the intake cam 1 41, the swing amplitude of the intake rocker arm 7 is increased to the same as the swing amplitude of the intake rocker arm 2 8, thereby increasing the lift of the intake valve 5 and the intake volume, ensuring more complete engine combustion, reducing emissions, and optimizing engine performance.

[0045] When the engine speed decreases, the drive assembly 9 retracts to release the linkage pin 11, and the linkage pin 11 is released from the pin hole 10 under the action of the return spring 16, and returns to the position as shown in FIG. Fig.10 In the state shown, the intake rocker arm 1 7 and the intake rocker arm 2 8 swing independently, the lift of the intake valve 5 decreases, and the intake amount decreases.

[0046] Embodiment 2

[0047] The structure and principle of this embodiment are basically the same as those of the first embodiment, except that the driving assembly 9 is a push rod motor, and the working principle of the push rod motor is to convert the rotational motion of the motor into the linear reciprocating motion of the push rod, and then use the push rod of the push rod motor to push the linkage pin 11 to move. When the push rod of the push rod motor is extended, the linkage pin 11 can be extended into the pin hole 10, and when the push rod of the push rod motor is retracted, the linkage pin 11 is disengaged from the pin hole 10 under the action of the reset spring 16.

[0048] 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.

[0049] Although this article uses the terms 1. cylinder head; 1a. mounting boss; 1a1. plug-in hole; 1a2. guide hole; 2. cylinder head; 21. support portion; 211. clearance step; 3. rocker shaft; 4. camshaft; 41. intake cam one; 42. intake cam two; 43. exhaust cam; 44. lobe; 5. intake valve; 6. exhaust rocker arm; 7. intake rocker arm one; 71. sleeve portion; 8. intake rocker arm two; 81. extension portion; 82. socket portion; 9. drive assembly; 91. push rod; 92. electromagnet; 921. end portion; 922. ejector pin; 10. pin hole; 11. linkage pin; 12. mounting hole one; 13. fastener; 14. mounting hole two; 15. torsion spring; 16. return spring; 17. oil seal, 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; any additional limitations interpreted as these terms are contrary to the spirit of the present invention.

Claims

1. A variable valve structure of an engine, the engine comprising a cylinder cover (1) and a cylinder head (2), wherein a rocker arm shaft (3), a camshaft (4) and an intake valve (5) are arranged in the cylinder head (2), characterized in that: The variable valve structure comprises an intake rocker arm 1 (7) and an intake rocker arm 2 (8) arranged on a rocker arm shaft (3); the camshaft (4) is provided with an intake cam 1 (41) and an intake cam 2 (42); the lobe tip (44) of the intake cam 2 (42) is higher than the lobe tip (44) of the intake cam 1 (41); the intake rocker arm 1 (7) abuts against the outer peripheral surface of the intake cam 1 (41) and can drive the intake valve (5) to open and close; the intake rocker arm 1 (7) is provided with a linkage pin (11) parallel to the rocker arm shaft (3); The linkage pin (11) is located on a side of the rocker shaft (3) close to the intake valve (5) and is arranged higher than the rocker shaft (3); the second intake rocker arm (8) is abutted against the outer peripheral surface of the second intake cam (42); the second intake rocker arm (8) is provided with a pin hole (10) which is parallel to the linkage pin (11) and matches the outer diameter of the linkage pin (11); the cylinder head (1) is provided with a drive assembly (9); the drive assembly (9) is located on the outer side of the linkage pin (11) in the axial direction and can push the linkage pin (11) so that the linkage pin (11) partially extends into the pin hole (10).

2. The variable valve structure of the engine according to claim 1, characterized in that: The cylinder head (2) has two plate-shaped support parts (21) arranged opposite to each other, and the two ends of the rocker arm shaft (3) are respectively fixedly arranged on the two support parts (21). The inner wall of the cylinder cover (1) has a mounting protrusion (1a) for mounting a drive assembly (9), and a clearance step (211) for avoiding the mounting protrusion (1a) is provided on the support part (21) close to the drive assembly (9).

3. The variable valve structure of the engine according to claim 2, characterized in that: The step (211) is provided with a mounting hole (12) penetrating the bottom surface of the cylinder head (2), and a fastener (13) for fixing the cylinder head (2) to the cylinder body of the engine is inserted into the mounting hole (12).

4. The variable valve structure of the engine according to claim 3, characterized in that: The two support parts (21) are each provided with a clearance step (211), and the clearance steps (211) on the two support parts (21) are both located on a side of the support part (21) close to the intake valve (5), and the top surfaces of the two support parts (21) on a side away from the intake valve (5) are each provided with a second mounting hole (14), the upper end of the first mounting hole (12) being lower than the upper end of the second mounting hole (14), and a fastener (13) for fixing the cylinder head (2) to the cylinder block of the engine is penetrated through the first mounting hole (12) and the second mounting hole (14).

5. The variable valve structure of the engine according to claim 2, 3 or 4, characterized in that: The second intake rocker arm (8) is located on the side of the first intake rocker arm (7) facing away from the drive assembly (9), and the side of the second intake rocker arm (8) facing away from the first intake rocker arm (7) has a cylindrical sleeve portion (82) sleeved on the rocker arm shaft (3), and the sleeve portion (82) is sleeved with a torsion spring (15) that enables the second intake rocker arm (8) to always be able to abut against and fit on the outer peripheral surface of the second intake cam (42).

6. The variable valve structure of the engine according to claim 5, characterized in that: The top of the intake rocker arm 1 (7) is provided with a cylindrical sleeve portion (71), and the intake rocker arm 2 (8) is provided with an extension portion (81) extending upwardly at an angle relative to the sleeve portion (82). The pin hole (10) is provided on the extension portion (81), and the linkage pin (11) is slidably inserted into the sleeve portion (71). A return spring (16) is also provided in the sleeve portion (71) and can drive the linkage pin (11) to move and escape from the pin hole (10).

7. The variable valve structure of the engine according to claim 5, characterized in that: The intake rocker arm 1 (7) and the intake rocker arm 2 (8) are in contact with each other, and the side of the intake rocker arm 1 (7) facing away from the intake rocker arm 2 (8) is in contact with a support portion (21) that is closer to the drive assembly (9).

8. The variable valve structure of an engine according to claim 2, 3 or 4, characterized in that: The mounting protrusion (1a) has a plug hole (1a1) and a guide hole (1a2) located inside the plug hole (1a1) and coaxial with the plug hole (1a1); the drive assembly (9) comprises a push rod (91) slidably inserted into the guide hole (1a2) and an electromagnet (92) plugged and positioned in the plug hole (1a1); the electromagnet (92) moves by pushing the linkage pin (11) through the push rod (91).

9. The variable valve structure of the engine according to claim 8, characterized in that: The electromagnet (92) comprises a shell having an end portion (921) and a push pin (922) that can be axially retracted relative to the shell. The end portion (921) of the electromagnet (92) is plugged and fixed in the plug hole (1a1), and the push pin (922) of the electromagnet (92) can push the push rod (91) to move axially.

10. The variable valve structure of the engine according to claim 8, characterized in that: The push rod (91) is sleeved with an oil seal (17), the oil seal (17) is sealingly matched with the inner wall of the plug hole (1a1), the guide hole (1a2) is concentrically arranged with the plug hole (1a1), and the diameter of the plug hole (1a1) is larger than the diameter of the guide hole (1a2).

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