Variable lift valve device of engine and motorcycle engine

Abstract

The utility model discloses a variable-lift valve device of an engine. The variable-lift valve device comprises a cam assembly, a valve rocker arm, a high-lift rocker arm and a low-lift rocker arm. The valve rocker arm is provided with a movable linkage pin; when the linkage pin retreats from the position below the high-lift rocker arm, the low-lift rocker arm drives the valve rocker arm to swing, and the high-lift rocker arm swings in an empty mode. When the linkage pin enters the position below the high-lift rocker arm, the high-lift rocker arm abuts against the linkage pin to drive the valve rocker arm to swing, and the low-lift rocker arm swings in an empty mode. Compared with a variable valve lift rocker arm structure in the prior art, under the high-speed working condition, inertia applied to a valve spring can be reduced, the design force value of the valve spring can be reduced, power consumed by the variable valve lift rocker arm mechanism can be reduced, and the dynamic performance of an engine can be improved to a greater extent. The utility model further discloses a motorcycle engine comprising the variable lift valve device of the engine.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of variable-lift valve train of engine, specifically to a kind of variable-lift valve train of motorcycle engine. BACKGROUND

[0002] Valve lift refers to the maximum height of engine valve when opening, which directly affects the engine intake and exhaust volume, thus affecting the performance of engine. The demand of engine under different conditions, at high speed area, larger valve lift is needed to improve intake efficiency and combustion efficiency; while at low speed area, smaller valve lift is helpful to improve torque and fuel economy. However, the traditional motorcycle engine valve lift is fixed and unchangeable, the intake or exhaust cam profile on camshaft only has one kind, and such cam profile is a balance considering high speed and low speed conditions, and the result is that neither the best high speed power nor the best low speed torque can be obtained.

[0003] The introduction of variable valve lift technology is to solve this problem, and the variable valve lift structure on motorcycle engine generally adopts two kinds of intake or exhaust cam profile on camshaft to realize the valve lift demand at low speed and high speed. Patent document EP2821601B1 discloses a variable valve lift structure of motorcycle engine, in which low lift and high lift two kinds of intake cam profile are provided on camshaft, one kind of exhaust cam profile is provided, one low lift intake rocker arm, one high lift intake rocker arm and one exhaust rocker arm are provided, and the low lift intake rocker arm and the high lift intake rocker arm are connected integrally by pin shaft to realize high lift movement of valve under high speed condition of engine.

[0004] Chinese patent document CN104251146B also discloses an engine, a first rocker arm is supported by a rocker arm shaft and is configured to actuate a valve. A second rocker arm is supported by the rocker arm shaft and is arranged side by side with the first rocker arm in an axial direction of the camshaft. A switching pin member is movable in the axial direction of the camshaft, and in a first position, the switching pin member links the first rocker arm and the second rocker arm and oscillates together with the first rocker arm and the second rocker arm. The switching pin member is located on an end portion side of the valve with respect to the rocker arm shaft as viewed in the axial direction of the camshaft.

[0005] In the above patent documents, when switching the valve lift demand at low speed and high speed, it is realized by the combination or disconnection of two rocker arms. After the two rocker arms are connected integrally, the rotational inertia is large at high speed, and larger valve spring force and rocker arm torsional spring force are needed, which leads to large power consumption of the variable valve lift structure itself, which means that the engine valve train itself consumes more power, and the power performance of the engine is reduced. UTILITY MODEL CONTENTS

[0006] The utility model discloses a variable lift valve structure of engine, including cam assembly, valve rocker arm, high lift rocker arm and low lift rocker arm, and the valve rocker arm is equipped with the linkage pin of removal, wherein: when the linkage pin exits below high lift rocker arm, low lift rocker arm drives valve rocker arm to swing, and high lift rocker arm is empty swing, when the linkage pin enters below high lift rocker arm, high lift rocker arm is driven valve rocker arm to swing by resisting linkage pin, and low lift rocker arm is empty swing.

[0007] In the scheme, when executing high lift action during the operation of the cam assembly, the linkage pin enters below the high lift rocker arm, the high lift rocker arm swings and then abuts against the linkage pin, and drives the valve rocker arm to swing, at this time, the low lift rocker arm is empty swing and will not contact the valve rocker arm, so the rotational inertia of the low lift rocker arm will not be applied to the valve; when executing low lift action, since the linkage pin exits below the high lift rocker arm, after the high lift rocker arm and the low lift rocker arm swing, the valve rocker arm is driven to swing by the low lift rocker arm, the high lift rocker arm will not contact the linkage pin, so it will not contact the valve rocker arm, and the high lift rocker arm is empty swing, so the rotational inertia of the high lift rocker arm will not be applied to the valve.

[0008] Therefore, compared with the prior art, in the scheme, the contact state of the high lift rocker arm and the low lift rocker arm with the valve rocker arm is changed by the movement of the linkage pin, and under high-speed working conditions or low-speed working conditions, only the rotational inertia of one of the lift rocker arms is applied to the valve, especially under high-speed working conditions, only the rotational inertia of the high lift rocker arm is applied to the valve, which can reduce the design force value of the valve spring, reduce the consumption power of the variable valve lift rocker arm structure itself, and thus can greatly improve the engine performance.

[0009] Preferably, the low lift rocker arm and the high lift rocker arm are provided with a swing part at the end facing the valve rocker arm, when the linkage pin exits below the swing part of the high lift rocker arm, the swing part of the high lift rocker arm does not contact the valve rocker arm, and the swing part of the low lift rocker arm contacts the valve rocker arm; when the linkage pin enters below the swing part of the high lift rocker arm, the swing part of the high lift rocker arm contacts the valve rocker arm, and the swing part of the low lift rocker arm does not contact the valve rocker arm under the non-base circle segment of the cam assembly. In the scheme, the switching of the high and low lift movements of the valve is realized by the cooperation of the swing part on the high lift rocker arm and the low lift rocker arm with the linkage pin, and the structure is simple.

[0010] Preferably, the valve rocker arm is provided with a linkage pin hole for installing the linkage pin, and the linkage pin is provided with a return spring. In the scheme, after the return spring is arranged in the linkage pin hole, when the linkage pin is subjected to external force, the linkage pin enters below the high lift rocker arm, and when the external force is removed, the linkage pin exits below the high lift rocker arm under the action of the return spring, and the structure is simple.

[0011] Preferably, the linkage pin hole is provided with a stop collar for limiting the movement of the linkage pin.

[0012] Preferably, the rocker arm core is further provided, the valve rocker arm is provided with a rocker arm sleeve, the high-lift rocker arm is sleeved on the low-lift rocker arm, the low-lift rocker arm is sleeved on the rocker arm sleeve, and the low-lift rocker arm and the high-lift rocker arm swing around the rocker arm core axis independently.

[0013] Preferably, the rocker arm sleeve is provided with a displacement part.

[0014] Preferably, the low-lift rocker arm and the high-lift rocker arm are both provided with a rocker torsional spring, and one of the rocker torsional springs is embedded in the other.

[0015] Preferably, the end of the rocker arm sleeve is provided with a torsional spring fixing sleeve, the torsional spring fixing sleeve is provided with a limiting part corresponding to one end of the two rocker torsional springs, and the low-lift rocker arm and the high-lift rocker arm are both provided with an installation part corresponding to the other end of the rocker torsional spring.

[0016] Preferably, the high-lift rocker arm or the low-lift rocker arm close to the torsional spring fixing sleeve is provided with a displacement area of the rocker torsional spring.

[0017] Preferably, the torsional spring fixing sleeve is provided with a flat surface.

[0018] Preferably, the torsional spring fixing sleeve is further provided with a stop washer.

[0019] In the second aspect, the utility model provides a motorcycle engine, including cylinder head, wherein: still include the engine variable lift valve device as described above.

[0020] The utility model has the advantages of:

[0021] 1. The utility model discloses a linkage pin's movement changes the contact state of high lift rocker arm and low lift rocker arm and valve rocker, under high speed working condition or low speed working condition, only the rotational inertia of one lift rocker arm is applied to the valve, namely, under low speed working condition, only the rotational inertia of low lift rocker arm is applied to the valve, under high speed working condition, only the rotational inertia of high lift rocker arm is applied to the valve. Compared with prior art variable valve lift rocker arm structure, under high speed working condition, the inertia applied to the valve spring can be reduced, the valve spring design force value can be reduced, the power consumption of variable valve lift rocker arm mechanism itself is reduced, and the engine power performance is improved to a greater extent.

[0022] 2. The utility model discloses have light weight, compact size and the like characteristics, can reduce the engine weight and volume, be applicable to the engine of using variable valve lift technology. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is the partial view of engine of the utility model a kind of engine variable lift valve device and motorcycle engine embodiment;

[0024] Figure 2 It is the schematic diagram of engine variable lift valve device embodiment 1;

[0025] Figure 3 It is cylinder head structure schematic diagram;

[0026] Figure 4 It is Figure 2 Variable valve lift rocker arm assembly explosion map in it;

[0027] Figure 5 It is valve rocker structure schematic diagram;

[0028] Figure 6 It is low lift rocker arm structure schematic diagram;

[0029] Figure 7 It is high lift rocker arm structure schematic diagram;

[0030] Figure 8 It is torsion spring fixing sleeve structure schematic diagram;

[0031] Figure 9 It is low lift rocker arm combination schematic diagram;

[0032] Figure 10 It is high lift rocker arm combination schematic diagram;

[0033] Figure 11 It is variable valve lift rocker arm assembly structure schematic diagram;

[0034] Figure 12Structure diagram of variable valve lift rocker arm assembly in low lift working state;

[0035] Figure 13 Structure diagram of variable valve lift rocker arm assembly in high lift working state;

[0036] Figure 14 Lift difference diagram between low valve lift and high valve lift;

[0037] Figure 15 Sectional view of variable valve lift rocker arm assembly;

[0038] Figure 16 Structure diagram of variable valve lift rocker arm assembly embodiment 2;

[0039] Figure 17 Axial view of variable valve lift rocker arm assembly embodiment 2;

[0040] Figure 18 Structure diagram of low lift rocker arm 3 in embodiment 2. DETAILED DESCRIPTION

[0041] The following will be further explained in detail through specific embodiments:

[0042] The reference signs in the attached drawings of the specification include: camshaft 1, low lift intake cam 1-1, high lift intake cam 1-2, valve rocker arm 2, valve rocker arm body 2-1, rocker arm shaft sleeve 2-2, linkage pin 2-3, return spring 2-4, stop collar 2-5, valve adjusting screw 2-6, low lift rocker arm 3, low lift rocker arm body 3-1, roller bearing 3-2, low lift rocker arm shaft sleeve 3-3, high lift rocker arm 4, rocker arm sliding plate 4-1, rocker arm bow 4-2, third rocker arm 4-3, electromagnetic valve push rod 5, electromagnetic valve 6, valve 7, rectangular torsion spring 8, first end of rectangular torsion spring 8-1, second end of rectangular torsion spring 8-2, circular torsion spring 9, first end of circular torsion spring 9-1, second end of circular torsion spring 9-2, torsion spring fixing sleeve 10, first clamping groove 10-1, second clamping groove 10-2, stop washer 11, cylinder head 12, low lift intake rocker arm assembly 14, high lift intake rocker arm assembly 15, rocker arm assembly 16, rocker arm mandrel 17, give way part a, first rocker arm b, linkage pin hole c, first oil hole d, second oil hole e, rectangular torsion spring clamping groove f, second rocker arm g, third oil hole h, circular torsion spring mounting hole j, first conical protrusion n, second conical protrusion m, give way area t.

[0043] The embodiment is basically as shown in the attached drawings Figure 1The figure shows a variable lift valve train for an engine, comprising a cam assembly and a rocker arm assembly 16. The rocker arm assembly 16 comprises a valve rocker arm 2, a high-lift rocker arm 4, and a low-lift rocker arm 3. The cam assembly and the valve rocker arm 2 are located on opposite sides of the rocker arm assembly 16. The valve rocker arm 2 is provided with a movable linkage pin 2-3. When the linkage pin 2-3 exits from under the high-lift rocker arm 4, the low-lift rocker arm 3 drives the valve rocker arm 2 to swing, while the high-lift rocker arm 4 swings idle. When the linkage pin 2-3 enters under the high-lift rocker arm 4, the high-lift rocker arm 4 presses against the linkage pin 2-3 to drive the valve rocker arm 2 to swing, while the low-lift rocker arm 3 swings idle.

[0044] This embodiment also discloses a motorcycle engine, including a cylinder head and the above-mentioned engine variable lift valve device.

[0045] Example 1

[0046] like Figures 1-15 As shown, an engine variable lift valve device includes a camshaft 1, a valve rocker arm 2, a low lift rocker arm 3, a high lift rocker arm 4, a solenoid valve push rod 5, a solenoid valve 6, two rocker arm torsion springs, a torsion spring fixing sleeve 10, a backstop washer 11, an exhaust rocker arm 13 and a rocker arm core shaft 17. The two rocker arm torsion springs are a rectangular torsion spring 8 and a circular torsion spring 9. The valve rocker arm 2, low-lift rocker arm 3, high-lift rocker arm 4, rectangular torsion spring 8, circular torsion spring 9, torsion spring fixing sleeve 10, and back-off washer 11 are assembled on the cylinder head 12 of the motorcycle engine through the rocker arm core shaft 17. The valve rocker arm 2 contacts the intake valve 7 through the valve adjusting screw 2-6, the low-lift rocker arm 3 contacts the low-lift intake cam 1-2 through the roller 3-2, and the high-lift rocker arm 4 contacts the high-lift intake cam 1-1 through the rocker arm slide 4-1. The valve rocker arm 2 and the low-lift rocker arm 3 constitute a complete low-lift intake rocker arm assembly 14, and the valve rocker arm 2 and the high-lift rocker arm 4 constitute a complete high-lift intake rocker arm assembly 15.

[0047] like Figure 5 As shown, the valve rocker arm 2 includes a valve rocker arm body 2-1 and a rocker arm sleeve 2-2. The valve rocker arm 2 is also provided with a linkage pin hole c, a linkage pin 2-3, a return spring 2-4, a stop collar 2-5, and the rocker arm sleeve 2-2, wherein the stop collar 2-5 is an elastic retaining ring. The end of the linkage pin 2-3 is provided with a first conical protrusion n. The rocker arm sleeve 2-2 and the valve rocker arm body 2-1 are separate and press-fitted onto the rocker arm body 2-1 without relative sliding between the two. The rocker arm sleeve 2-2 is provided with a first oil hole d for lubrication. The valve rocker arm body 2-1 is provided with a clearance portion a. The clearance portion a cooperates with the clearance height h3 of the low-lift rocker arm 3 to shorten the dimension of the rocker arm assembly 16 along the axis of the rocker arm core shaft 17, making the structure compact. The valve rocker arm body 2-1 is provided with a first rocking portion b, which is formed by precision machining. The valve rocker arm body 2-1 is also provided with a linkage pin hole c.

[0048] As shown in Figure 6 , the low-lift rocker arm 3 comprises a low-lift rocker arm body 3-1 and a roller bearing 3-2, the low-lift rocker arm body 3-1 is provided with a low-lift rocker arm sleeve 3-3, the low-lift rocker arm sleeve 3-3 is integrated with the low-lift rocker arm body 3-1, the low-lift rocker arm sleeve 3-3 is provided with a rectangular torsion spring clamping groove f and a second oil hole e for lubrication; the low-lift rocker arm body 3-1 is provided with a second swing part g, which is formed by fine machining.

[0049] As shown in Figure 7 , the high-lift rocker arm 4 is provided with a rocker arm slide plate 4-1, a rocker arm bow 4-2, a third swing part 4-3, a third oil hole h and a circular torsion spring mounting hole j, the rocker arm slide plate 4-1 is arc-shaped. The high-lift rocker arm 4 is sleeved on the low-lift rocker arm sleeve 3-3, and the inner hole of the high-lift rocker arm 4 is provided with a displacement area t, so that the rectangular torsion spring 8 on the low-lift rocker arm 3 will not interfere with the high-lift rocker arm 4 when it is twisted.

[0050] As shown in Figure 4 and Figure 8 , the torsion spring fixing sleeve 10 is provided with a first clamping groove 10-1 and a second clamping groove 10-2, the second end 8-2 of the rectangular torsion spring 8 is clamped into the first clamping groove 10-1, the second end 9-2 of the circular torsion spring 9 is clamped into the second clamping groove 10-2, the torsion spring fixing sleeve 10 is cylindrical, the inner cavity diameter of the torsion spring fixing sleeve 10 is larger than the diameter of the circular torsion spring 9, which can accommodate the rectangular torsion spring 8 and the circular torsion spring 9. The outer periphery of the torsion spring fixing sleeve 10 is provided with a first flat surface r, a second flat surface s and a third flat surface q, the third flat surface q cooperates with the rotation stopping surface 12-1 of the cylinder head 12 to prevent the torsion spring fixing sleeve 10 from rotating around the rocker arm core shaft 17, and the stop washer 11 is assembled on the side surface of the clamping groove 10-1 and the clamping groove 10-2 of the torsion spring fixing sleeve 10, which can prevent the rectangular torsion spring 8 and the circular torsion spring 9 from exiting the clamping groove 10-1 and the clamping groove 10-2.

[0051] As shown in Figure 4 and Figure 11As shown, the assembly relationship between the low-lift rocker arm 3 and the high-lift rocker arm 4 is as follows: the low-lift rocker arm 3 is sleeved into the rocker arm sleeve 2-2 of the valve rocker arm 2 through the inner hole of the low-lift rocker arm sleeve 3-3, and the two are clearance fit, the low-lift rocker arm 3 can rotate freely around the rocker arm sleeve 2-2, the high-lift rocker arm 4 is sleeved into the low-lift rocker arm sleeve 3-3, and the two are clearance fit, the high-lift rocker arm 4 can rotate freely around the low-lift rocker arm sleeve 3-3; the rectangular torsion spring 8 and the circular torsion spring 9 are installed in the cylindrical inner cavity of the torsion spring fixing sleeve 10, the second end 8-2 of the rectangular torsion spring 8 is clamped into the clamping groove 10-1 of the torsion spring fixing sleeve 10, the second end 9-2 of the circular torsion spring 9 is clamped into the clamping groove 10-2, the first end 8-1 of the rectangular torsion spring 8 is clamped into the rectangular torsion spring clamping groove f of the low-lift rocker arm 3, the first end 9-1 of the circular torsion spring 9 is installed in the circular torsion spring mounting hole j of the high-lift rocker arm 4, and the stop washer 11 is arranged on the side surface of the clamping groove 10-1 and the clamping groove 10-2 of the torsion spring fixing sleeve 10. The rocker arm assembly 16 after the above assembly is assembled to the cylinder head 12 of the engine through the rocker arm core shaft 17. During the assembly process, when the camshaft 1 is assembled into the cylinder head 12, the low-lift rocker arm 3 and the high-lift rocker arm 4 need to be lifted to a certain height, and when the low-lift rocker arm 3 and the high-lift rocker arm 4 are lifted, the rectangular torsion spring 8 and the circular torsion spring 9 will be driven to rotate around the axis of the rocker arm core shaft 17 by a certain angle, the torsion spring fixing sleeve 10 is abutted to the rotation stopping surface 12-1 on the cylinder head 12 through the third flat surface q, so that the torsion of the torsion spring fixing sleeve 10 along the axis of the rocker arm core shaft 17 is prevented, the rectangular torsion spring 8 and the circular torsion spring 9 will generate torsion force when torsion occurs, and the roller bearing 3-2 of the low-lift rocker arm 3 and the rocker slide 4-1 of the high-lift rocker arm 4 are tightly abutted against the low-lift intake cam 1-2 and the high-lift intake cam 1-1 respectively under the action of the rectangular torsion spring 8 and the circular torsion spring 9, as shown in Figure 2 .

[0052] The specific implementation process is as follows: when the engine speed is in the low-speed region, as shown in Figures 2-15 , the electromagnetic valve 6 does not work, the linkage pin 2-3 on the valve rocker arm 2 retreats to the direction of the electromagnetic valve push rod 5 under the action of the return spring 2-4, the linkage pin 2-3 has no contact relationship with the third rocker 4-3 of the high-lift rocker arm 4, when the camshaft 1 rotates, the low-lift intake cam 1-2 drives the low-lift rocker arm 3 to contact the first rocker b on the valve rocker arm 2 through the second rocker g, so that the valve rocker arm 2 swings around the axis of the cam core shaft 17, as shown in Figure 12 , and further drives the valve 7 to move through the contact between the valve adjusting screw 2-6 and the valve 7, at this time, the low-lift intake rocker 3 and the valve rocker 2 form a complete low-lift intake rocker combination 14 to drive the valve 7 to move with low lift.

[0053] In the low speed region of the engine, the high-lift cam 1-1 on the camshaft 1 makes the high-lift rocker arm 4 swing through the rocker arm slide plate 4-1. Since the third rocker arm 4-3 does not contact the linkage pin 2-3, as shown in Figure 12 , the high-lift rocker arm 4 swings idly, i.e. does not drive the valve 7. At this time, the idle swing does not allow the rocker arm slide plate 4-1 to be separated from the high-lift intake cam 1-1. Therefore, the circular torsion spring 9 is used to tightly press the high-lift rocker arm 4 against the high-lift intake cam 1-1 so as not to be separated.

[0054] When the engine speed is in the high speed region, the solenoid valve 6 works, and the solenoid valve 6 pushes the solenoid valve push rod 5 to axially move the linkage pin 2-3 towards the high-lift rocker arm 4. The linkage pin 2-3 is pushed to be kept under the third rocker arm 4-3 of the high-lift rocker arm 4. When the camshaft 1 rotates, the low-lift intake cam 1-2 and the high-lift intake cam 1-1 will drive the low-lift rocker arm 3 and the high-lift rocker arm 4 to swing. Since the lift of the high-lift intake cam 1-1 is higher than that of the low-lift cam 1-2, and the lift and the included angle of the high-lift cam 1-1 are greater than those of the low-lift cam 1-2, i.e. when the camshaft 1 rotates by a certain angle, the high-lift rocker arm 4 will swing with a greater amplitude than the low-lift rocker arm 3. The third rocker arm 4-3 on the high-lift rocker arm 4 first contacts the linkage pin 2-3, as shown in Figure 13 , the second rocker arm g on the low-lift rocker arm 3 is separated from the first rocker arm b of the valve rocker arm 2. The separation distance is determined by the high-lift and low-lift valve lift difference, as shown in Figure 13 . At this time, the high-lift rocker arm 4 and the valve rocker arm 2 form a complete high-lift intake rocker arm combination 15 to drive the valve 7 to move with high lift. Similarly, the low-lift rocker arm 3 also needs to use the rectangular torsion spring 8 to prevent it from being separated when it idles.

[0055] As shown in Figure 15 , when the engine speed is in the low speed region, the linkage pin 2-3 is returned under the action of the return spring 2-4. The second tapered convex part m of the linkage pin 2-3 is smaller than the side surface of the high-lift rocker arm 4, and is under the third rocker arm 4-3 of the high-lift rocker arm 4. The second tapered convex part m and the third rocker arm 4-3 of the high-lift rocker arm 4 have an overlapping area. The third rocker arm 4-3 of the high-lift rocker arm 4 is a circular arc type, and the diameter of the circular arc is greater than the diameter of the linkage pin 2-3. The center line of the circular arc is collinear with the linkage pin hole c. When the low-lift rocker arm 3 and the high-lift rocker arm 4 are on the base circle of the camshaft 1, the linkage pin 2-3 can be flexibly inserted into or withdrawn from the third rocker arm 4-3 of the high-lift rocker arm 4.

[0056] Example 2

[0057] As shown in Figures 16-18The difference between the embodiment and the embodiment 1 is that the second swing part g of the low-lift rocker arm 3 is changed from flat shape to arc shape, the linkage pin 2-3 always makes the second swing part g of the low-lift rocker arm 3 in constant contact with the linkage pin 2-3 at the initial position when the electromagnetic valve 6 is not working, the engine drives the low-lift rocker arm assembly 14 to push the valve 7 to make low-lift movement by the low-lift intake cam 1-2 at the low speed area. When the engine is at high speed area, the electromagnetic valve 6 pushes the electromagnetic valve push rod 5 to make the linkage pin 2-3 move along the axial direction, so that the linkage pin 2-3 enters the below of the third swing part 4-3 of the high-lift rocker arm 4, and the third swing part 4-3 of the high-lift rocker arm 4 is in contact with the linkage pin 2-3. The lift and the included angle of the high-lift intake cam 1-1 are greater than those of the low-lift intake cam 1-2, the second swing part g on the low-lift rocker arm 3 is separated from the linkage pin 2-3, at this time, the cam shaft 1 drives the high-lift rocker arm assembly 15 to push the valve 7 to make high-lift movement by the high-lift intake cam 1-1.

[0058] The above is only the embodiment of the present application, and the specific structure and the like of the known scheme are not described in detail, the ordinary technical personnel in the art knows all the ordinary technical knowledge in the technical field of the present application before the application date or the priority date, can know all the prior art in the field, and has the ability to apply the conventional experimental means before the date, the ordinary technical personnel in the art can improve and implement the scheme under the enlightenment of the present application, some typical known structure or known method should not be the obstacle for the ordinary technical personnel to implement the present application. It should be pointed out that for the technical personnel in the art, without departing from the structure of the present application, a number of modifications and improvements can be made, which should also be regarded as the protection scope of the present application, which will not affect the effect and practicality of the present application. The protection scope of the present application should be subject to the content of its claims, and the specific implementation mode and the like in the specification can be used to explain the content of the claims.

Claims

1. An engine variable-lift valve apparatus comprising a cam assembly, a valve rocker arm, a high-lift rocker arm, and a low-lift rocker arm; the valve rocker arm is provided with a moving link pin; characterized in that: When the linkage pin exits below the high-lift rocker arm, the low-lift rocker arm drives the valve rocker arm to swing, and the high-lift rocker arm is idle; when the linkage pin enters below the high-lift rocker arm, the high-lift rocker arm drives the valve rocker arm to swing, and the low-lift rocker arm is idle.

2. The engine variable-lift valve apparatus of claim 1 wherein: The low-lift rocker arm and the high-lift rocker arm are provided with a swing part towards one end of the valve rocker arm, when the linkage pin exits below the high-lift rocker arm, the swing part of the high-lift rocker arm is not in contact with the valve rocker arm, and the swing part of the low-lift rocker arm is in contact with the valve rocker arm; when the linkage pin enters below the high-lift rocker arm, the swing part of the high-lift rocker arm is in contact with the valve rocker arm, and the swing part of the low-lift rocker arm is not in contact with the valve rocker arm in the non-base circle section of the cam assembly.

3. The engine variable-lift valve apparatus of claim 2 wherein: The valve rocker arm is provided with a linkage pin hole for installing the linkage pin, and the linkage pin is provided with a return spring.

4. The engine variable-lift valve apparatus of claim 3 wherein: The linkage pin hole is provided with a stop collar for limiting the movement of the linkage pin.

5. The engine variable-lift valve apparatus of any one of claims 1-4, characterized by: Further comprising a rocker shaft, the valve rocker arm is provided with a rocker shaft sleeve, the high-lift rocker arm is sleeved on the low-lift rocker arm, the low-lift rocker arm is sleeved on the rocker shaft sleeve, and the low-lift rocker arm, the high-lift rocker arm and the valve rocker arm swing around the axis of the rocker shaft separately.

6. The engine variable-lift valve apparatus of claim 5 wherein: The rocker shaft sleeve is provided with a clearance part.

7. The engine variable-lift valve apparatus of claim 6 wherein: The low-lift rocker arm and the high-lift rocker arm are both provided with a rocker torsional spring, and one of the rocker torsional springs is embedded in the other.

8. The engine variable-lift valve apparatus of claim 7 wherein: The end of the rocker shaft sleeve is provided with a torsional spring fixing sleeve, the torsional spring fixing sleeve is provided with a limiting part corresponding to one end of the two rocker torsional springs, and the low-lift rocker arm and the high-lift rocker arm are both provided with a mounting part corresponding to the other end of the rocker torsional spring.

9. The engine variable-lift valve apparatus of claim 8 wherein: The high-lift rocker arm or the low-lift rocker arm close to the torsional spring fixing sleeve is provided with a clearance area for the rocker torsional spring.

10. The engine variable-lift valve apparatus of claim 8 wherein: The torsional spring fixing sleeve is provided with a flat surface.

11. The engine variable-lift valve apparatus of claim 10 wherein: The torsional spring fixing sleeve is further provided with a stop washer.

12. A motorcycle engine comprising a cylinder head, characterised in that: Further comprising the engine variable lift valve device according to any one of claims 1-11.

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