JP2002250210A - Valve lift amount variable apparatus of valve system of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify constitution of a valve lift amount variable apparatus of a valve system of an internal combustion engine and to facilitate to form the valve lift amount variable apparatus. SOLUTION: A camshaft 13 comprises: a camshaft body 15 positioned on an axial center 12, a low cam nose 16 fixed to the camshaft body 15 and cam- engaged with a valve 5; a high cam nose 17 disposed to neighbor to the low cam nose 16; a supporting means 20 that guides the high cam nose 17 to be capable of moving forward A and moving backward B so that a cam projecting end 19 can project and reverse by an amount larger than a cam projecting end 18 of the low cam nose 16, and makes the camshaft body 15 support the high cam nose 17; and a locking means 22 that can detachably lock the high cam nose 17 to the camshaft body 17. Accompanied by rotations of the camshaft 13, the high cam nose 17 is engaged with the valve 5 to move forward A and/ or move backward B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable valve lift device in a valve operating mechanism of an internal combustion engine which makes the valve lift of an intake valve and an exhaust valve of a four-cycle internal combustion engine variable according to operating conditions such as the number of revolutions. Things.

[0002]

2. Description of the Related Art As a variable valve lift device in the above-described valve train, there is a device disclosed in Japanese Patent No. 2645282.

[0003] According to the above publication, the valve operating mechanism includes:
A camshaft is provided which engages the valve with the valve as the shaft rotates about the axis to open and close the valve.

The camshaft includes a camshaft main body located on the shaft center, a low cam nose fixed to the camshaft main body and cam-engaging with the valve, and a low cam nose in an axial direction of the camshaft main body. And a high cam nose arranged so that the cam projection end of the high cam nose protrudes from the cam projection end of the low cam nose radially outward of the camshaft main body and can be retracted. And a spring for elastically urging the high cam nose to move backward, and a spring against the elastic force of the spring. Hydraulic means for enabling the high cam nose to move forward, and locking the high cam nose to the camshaft body in a state where the high cam nose moves forward. And a locking means for the ability.

[0005] The bearing means may be formed in the camshaft main body and have a rectangular cross section as viewed from the line of sight along the axis, and the high cam nose may be used to connect the support body to the camshaft main body. A pair of sliding surfaces which are arranged so as to be sandwiched from each outer side in the radial direction and which are opposite to each other among the outer surfaces of the support body, and which are slidable in the forward and backward movement directions. During the forward and backward movements of the high cam nose, each sliding contact surface comes into sliding contact with the pair of outer surfaces and is guided in a predetermined direction.

When the camshaft rotates around the axis with the operation of the internal combustion engine having the above-described structure, the high cam nose may be set in the "retracted state" in a state in which the high cam nose is moved backward by the biasing force of the spring. Since the cam protruding end of the high cam nose retreats inward in the radial direction of the camshaft main body from that of the low cam nose, only the low cam nose is cam-engaged with the valve, and this valve has a small lift. The opening and closing valve is operated by the amount, and the intake and exhaust states corresponding to this are obtained.

On the other hand, the high cam nose is set in a "projecting state" in which the high cam nose is moved forward by hydraulic means against the elastic force of the spring, and the high cam nose is locked to the camshaft main body by locking means. Then, the cam protruding end of the high cam nose protrudes outward in the radial direction of the camshaft main body more than that of the low cam nose in a “projecting state”
Is held, only the high cam nose is cam-engaged with the valve, and the valve is operated to open and close with a large lift amount, so that a suction and exhaust state corresponding to this is obtained.

[0008]

By the way, in the above-mentioned prior art, the forward and backward movements of the high cam nose are performed by hydraulic means and a spring. Increasingly, its configuration is becoming more complicated.

Further, in the above-mentioned prior art, as described above, since the cross section of the bearing body is rectangular, if this cross section is simply enlarged, the occupied space becomes excessive and the weight becomes heavy. There is a limit to increasing the cross-section, and it can be kept small.Therefore, when the high cam nose moves forward and backward, there is a possibility that a pair of sliding contact surfaces of the high cam nose may be twisted with respect to the support body. In this case, the smooth movement of the high cam nose may be hindered. Therefore, it is conceivable to increase the capacity of the spring or the hydraulic means. However, in this case, the configuration of the valve lift variable device becomes more complicated.

Further, since the support has a rectangular cross section, the formation of the support is complicated. Therefore, the valve lift variable device has a large number of parts as described above. The molding is complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a simple structure of a variable valve lift device in a valve train of an internal combustion engine, and can be easily formed. The task is to do so.

[0012]

Means for Solving the Problems A variable valve lift device in a valve train of an internal combustion engine according to the present invention for solving the above problems is as follows.

According to the first aspect of the present invention, there is provided a cam shaft 13 for cam-engaging with the valve 5 with the rotation about the shaft center 12 to open and close the valve 5. A low cam nose 16 fixed to the camshaft main body 15 and cam-engaged with the valve 5;
A high cam nose 17 disposed adjacent to the low cam nose 16 in the axial direction of the camshaft body 15;
The cam protruding end 19 of the high cam nose 17 protrudes from the cam protruding end 18 of the low cam nose 16 outward in the radial direction of the cam shaft main body 15, and moves back and forth through the high cam nose 17 so that it can be retracted. A and B are freely guided, and the high cam nose 1 is
Support means 20 for supporting the high cam nose 1
Locking means 2 for locking this high cam nose 17 to the camshaft main body 15 so that it can be detachably engaged with the camshaft 7 in the forward movement A.
2. The valve train of an internal combustion engine comprising:

With the rotation of the cam shaft 13, the high cam nose 17 engages with the valve 5 to move the forward movement A and
And / or to be moved back B.

According to a second aspect of the present invention, in addition to the first aspect, the support means 20 is supported by the camshaft main body 15 and moves the shaft center 12 in the forward and backward movement directions X of the high cam nose 17. A pair of bearing bodies 2 which are arranged to be spaced apart from each other
4 and 25 and the bearings 24 and 25 formed on the high cam nose 17 so as to sandwich the bearings 24 and 25 from the radial outside of the camshaft body 15.
And a pair of sliding contact surfaces 26 and 27 which are slidable in the forward and backward movement directions X, respectively.

According to a third aspect of the present invention, in addition to the second aspect of the invention, when viewed from the line of sight along the axial direction of the camshaft main body 15,
Each of the bearing members 24 and 25 has a circular shape.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a four-cycle internal combustion engine mounted on a vehicle such as a motorcycle or an automobile.

The cylinder 2 of the internal combustion engine 1 is formed with intake and exhaust passages 4 for connecting the outside of the cylinder 2 and the combustion chamber 3 formed therein to each other. A free intake and exhaust valve 5 is provided. The valve body 6 of the valve 5 includes a valve stem 7 and a valve body 8 integrally formed at one end of the valve stem 7.
Includes a lifter 9 elastically supported by a spring at the other end of the valve stem 7.

With the operation of the internal combustion engine 1,
A valve operating mechanism 11 for appropriately opening and closing each of the valves 5 is provided. The valve mechanism 11 includes a camshaft 1 supported by the cylinder 2 so as to be rotatable about an axis 12.
The camshaft 13 is linked to the crankshaft of the internal combustion engine 1. The cam shaft 13 has its axis 1
With two rotations, the valves 5 are pressed against the valves 5 by the elastic force of the spring to engage the cam to open and close the valves 5 against the elastic force.

The camshaft 13 has a camshaft main body 15 positioned on the shaft center 12 and a pair of camshafts 15 fixed to the camshaft main body 15 by being integrally formed therewith and cam-engaging with the lifter 9 of the valve 5. A low cam nose 16, a high cam nose 17 disposed between the low cam nose 16 in the axial direction of the camshaft main body 15 and adjacent to each of the low cam nose 16, and a camshaft main body 15.
The cam protruding end 1 of the high cam nose 17 is more radially outward than the cam protruding end 18 of the low cam nose 16.
The high cam nose 17 is provided so that the projection 9 can be retracted.
And a pushing means 21 for guiding the high cam nose 17 to the camshaft body 15 and for allowing the high cam nose 17 to make the forward movement A. When the high cam nose 17 is in the forward movement A, the high cam nose 17 is provided with locking means 22 which can be locked to and disengageable from the camshaft body 15.

In the above case, in the circumferential direction of the camshaft main body 15,
The cam protruding end 18 of the low cam nose 16 and the cam protruding end 19 of the high cam nose 17 are arranged at substantially the same position. The direction in which the high cam nose 17 moves forward and backward A and B as described above is hereinafter referred to as the forward and backward movement direction X. FIGS. 1 and 2 show a state in which the high cam nose 17 is moved backward B, which is referred to as a “retracted state”, in which the high cam nose 17 is moved forward A as described later. Is referred to as a “protruding state”.

The support means 20 includes the camshaft main body 15
The forward and backward movement directions X of the high cam nose 17
And a pair of first and second bearing members 24 and 25 arranged apart from each other with the axis 12 of the camshaft body 15 interposed therebetween, and the high cam nose 17 formed with the bearing members 24 and 2.
5 are arranged so as to be sandwiched from the respective outer sides in the radial direction of the camshaft main body 15, and each of the pair of first and second support members 24 and 25 is slidable in the forward and backward movement directions X, respectively. The first and second sliding contact surfaces 26 and 27 are provided.

The support means 20 will be described in more detail.

The first bearing member 24 is connected to the camshaft main body 15.
The camshaft main body 15 has a circular shape when viewed from a “line of sight” along the axial direction (FIG. 2). The axis 30 of the first support 24 is parallel to and offset from the axis 12.

On the other hand, one low cam nose 16 (a) of the two low cam noses 16, 16 is parallel to the axis 12 and moves in the forward and backward movement directions X with respect to the axis 12. A support hole 32 is formed on an axis 31 that is displaced in the opposite direction to the axis 30 of the first support 24, and the second support 25 is slidably inserted in the support hole 32 in the axial direction. The second support 25 is tightly fitted, and is supported by the camshaft body 15 via the low cam nose 16 (a). The support means 20 includes a spring 33 that elastically urges the second support body 25 toward the high cam nose 17 in the axial direction. As viewed from the “line of sight”, both the second support body 25 and the support hole 32 are circular.

A notch 36 that opens outward in the radial direction of the camshaft main body 15 is formed at an end 35 of the high cam nose 17 opposite to the cam protruding end 19 in the forward and backward movement directions X. The two surfaces facing each other in the notch 36 are the pair of first sliding contact surfaces 26, 26, and the notch 36 is fitted with the first support body 24, and the respective first sliding members 24 are formed. The sliding contact surface 26 goes to the outer peripheral surface of the first support 24 and is slidable in the backward movement direction X.

In the axial direction of the camshaft main body 15, the second
The high cam nose 1 facing the protruding end of the support body 25
A long groove 37 extending in the radial direction of the camshaft main body 15 in the forward and backward movement directions X is formed on the surface 7, and the two surfaces facing each other in the long groove 37 are formed by the pair of second grooves. Sliding contact surfaces 27, 27
The protruding end of the support 25 is fitted by the urging force of the spring 33 so that each of the second sliding surfaces 27 moves to the outer peripheral surface of the second support 25 and is freely slidable in the backward movement direction X. Have been.

As shown in FIGS. 1 and 2, when the high cam nose 17 is in the “retracted state”, the inner surface of the notch 36 is formed so as to prevent the high cam nose 17 from moving backward. Abutting the first bearing member 24 and / or an inner surface of one end of the elongated groove 37 radially outward of the camshaft body 15 against a protruding end of the second bearing member 25; Have been.

In FIG. 2, the pushing means 21 is constructed as follows.

That is, the end 35 of the high cam nose 17
In the "retracted state" and in the forward and backward movement directions X, the lower cam nose 16 is made to protrude outward from the end 43 opposite to the cam protruding end 18 of the low cam nose 16, and the pushing means 21
Has the end 35 of the high cam nose 17 protruding from the end 43 of the low cam nose 16 as described above.

In FIG. 3, the axis 12 of the cam shaft 13
With the rotation around, the end 35 of the high cam nose 17
Is engaged with the valve 5, the reaction force from the valve 5 causes the high cam nose 17 to make the forward movement A and to be brought into the "projecting state". That is, the pushing means 21 The above-mentioned engagement type is provided.

The centrifugal force generated in the high cam nose 17 due to the rotation of the cam shaft 13 around the axis 12,
The high cam nose 17 is moved in the forward movement A to be in the "projecting state", that is, the pushing means 21 is also provided with the centrifugal type.

In FIGS. 1 and 2, the pushing means 21 is
A substantially hermetic pressure oil chamber 39 surrounded by opposing surfaces of the low cam nose 16, an outer peripheral surface of the first support 24, and an inner inner surface of the notch 36;
And a first branch oil passage 41 formed in the first bearing member 24 and communicating the pressure oil chamber 39 and the oil passage 40 with each other. A hydraulic pump is connected to the oil passage 40 through a control valve.
The oil pressurized by the hydraulic pump is supplied to and discharged from the pressure oil chamber 39 through the oil passage 41 and the branch oil passage 41.

When the pressurized oil 42 is supplied to the pressure oil chamber 39 through the oil passage 40 and the branch oil passage 41, the oil 42 is pushed by the pressure of the oil 42 and the high cam nose 17 is pushed. The forward movement A is performed, and the “protruding state” is set.

When the oil 42 is discharged from the pressure oil chamber 39 through the oil passage 40 and the branch oil passage 41, the high cam nose 17 enters a free state in which the forward and backward movements A and B can be freely performed.

As described above, the pushing means 21 is of an engagement type having the end 35 of the high cam nose 17 projecting from the end 43 of the low cam nose 16 and engaging with the valve 5; There are a centrifugal type in which a centrifugal force is generated in the high cam nose 17 with the rotation of the rotary shaft 13 and a hydraulic type with a pressure oil chamber 39 and the like.
May be configured by at least one of these equations.

In FIG. 4, when the high cam nose 17 is in the "projecting state", the cam protruding end 19 of the high cam nose 17 engages with the valve 5 as the cam shaft 13 rotates around the axis 12. If so, the high cam nose 17 is moved backward B by the reaction force from the valve 5, and is brought into the "retreat state".

That is, in a free state in which the high cam nose 17 is not locked to the camshaft main body 15 by the locking means 22, the high cam nose 17 engages with the valve 5 and rotates every time the camshaft 13 rotates. , The forward movement A and the backward movement B are repeated once. In this case, only the low cam nose 16 is cam-engaged with the valve 5, and the valve 5 is opened and closed with a small lift amount.

In FIGS. 1 and 2, the locking means 22 comprises:
A bearing hole 44 formed on the other low cam nose 16 (b) of the two low cam noses 16, 16 on the shaft center 31 of the bearing body 25 and the bearing hole 32, and the bearing hole 44.
A locking body 45 which is fitted in a tightly slidable manner in the axial direction;
A support hole 47 formed on the cam projecting end 19 side of the high cam nose 17 on an axis 46 parallel to the axis 12, and a spacer 4 slidably fitted in the support hole 47 in the axial direction.
8, a second branch for connecting the oil passage 40 with the end face side of the locking body 45 opposite to the high cam nose 17 in the axial direction of the camshaft main body 15 in the locking body 45. An oil passage 49 is provided.

As seen from the above "line of sight", the bearing holes 44, 4
7 are both circular and each of these bearing holes 44, 47
Has substantially the same diameter as the bearing hole 32. The locking body 45 and the spacer 48 are both circular, and these 45 and 48 have substantially the same diameter as the second support 25. The support hole 47 for the spacer 48 is formed at the other end of the elongated groove 37 on the radially inward side of the camshaft main body 15, and in the “retracted state” of the high cam nose 17, the support hole 47 is formed. And the axis 46 of the spacer 48
Are displaced radially inward of the camshaft main body 15 from the shaft center 31 of the support body 25 and the support hole 32.

As shown in FIGS. 3, 5, and 6, when the high cam nose 17 is moved forward by the pushing means 21, and is brought into the "projecting state", the second support 25,
The shaft center 31 of the bearing hole 32, the bearing hole 44, and the locking body 45
On the other hand, the shaft center 46 of the bearing hole 47 and the spacer 48
Are to be matched.

In FIG. 7, the oil passage 40 and the branch oil passage 4
And pressurized oil 4 on the end face side of the locking body 45
2 is supplied and pushed against the pressure of the oil 42 while resisting the elastic force of the spring 33, and the locking member 45,
The spacer 48 and the second support body 25 are connected to the respective support holes 3.
2, 44, 47 are slid in the axial direction, and the locking body 45 is fitted over the bearing holes 44, 47, whereby
The high cam nose 17 is connected to the low cam nose 16
It is engaged with the camshaft main body 15 via (b) so as to be detachably engaged with the camshaft main body 15 and is held in the “projecting state”. And in this case,
Only the high cam nose 17 is cam-engaged with the valve 5, and the valve 5 is opened and closed with a large lift.

When the oil 42 is discharged from the end face side of the locking member 45 through the oil passage 40 and the branch oil passage 49, the second bearing member 25, the spacer 48, and the locking member 45 And returns to the original state shown in FIGS. 5 and 6, and the high cam nose 17 is again in the free state.

In the above case, the diameter and the cross-sectional area of the first branch oil passage 41 are made larger than those of the second branch oil passage 49.

FIG. 8 shows a modification of the present invention, in which a pair of low cam nose 16 and high cam nose 17 shown in FIGS. 45 are integrally formed.

Since the other constructions and functions and effects are the same as those of the above-described embodiment, the same reference numerals are given to the drawings and the description thereof will be omitted.

According to the above configuration, the high cam nose 17 is engaged with the valve 5 and the forward movement A and / or the backward movement B is performed as the cam shaft 13 rotates.

For this reason, a hydraulic means or a spring is conventionally provided to move the high cam nose 17 in the forward movement A and the backward movement B. However, as described above, the engagement with the valve 5 causes the high cam nose 17 to move forward. The hydraulic means and the spring are not required because of the movement of.

Therefore, the number of parts of the valve 5 lift variable device in the valve train 11 of the internal combustion engine 1 is reduced, and the configuration is simplified.

Further, as described above, the bearing means 20
The high cam nose 17 supported by the camshaft body 15
In the forward and backward movement directions X, a pair of bearing bodies 24 and 25 which are arranged apart from each other with the axis 12 interposed therebetween, and each of the bearing bodies 24 and 25 formed on the high cam nose 17 are connected to the camshaft body 15. And a pair of sliding surfaces 26, 2 which are arranged so as to be sandwiched from the outside in the radial direction, and which are slidable in the forward and backward movement directions X with respect to the respective bearing bodies 24, 25.
7 is provided.

For this reason, since the high cam nose 17 is supported by the pair of support members 24 and 25 which are largely separated from each other with the shaft center 12 interposed therebetween, the high cam nose 17 moves forward and backward A and B. When the above bearing body 2
The shaft center 12 is prevented from being twisted with respect to the shafts 4 and 25, and the movement of the high cam nose 17 is smoothly performed.

Therefore, the external force for moving the high cam nose 17 in the forward and backward movements A and B is small enough.
The structure of the valve 5 lift amount variable device in the valve mechanism 11 of the internal combustion engine 1 is further simplified.

The bearings 24 and 25 are each circular when viewed from the line of sight along the axial direction of the camshaft main body 15.

Therefore, as compared with the prior art in which the cross section of the bearing is rectangular, the bearings 24 and 25 can be formed more easily, that is, the lift amount of the valve 5 in the valve train 11 of the internal combustion engine 1. The variable device can be easily formed.

Since the surfaces of the bearing members 24 and 25 for slidingly contacting the sliding surfaces 26 and 27 are arc-shaped, the movement of the high cam nose 17 is made smoother. In this respect, the external force for moving the high cam nose 17 in the forward and backward movements A and B is small, and the configuration of the valve 5 lift amount variable device in the valve train 11 of the internal combustion engine 1 can be further simplified. .

In the illustrated example, the second support 25 is indirectly supported by the camshaft main body 15 via the low cam nose 16, but the camshaft main body 15 may directly support the support 25. . In the illustrated example, the high cam nose 17 is indirectly locked to the camshaft main body 15 via the low cam nose 16 by the locking means 22.
The high cam nose 17 may be directly engaged with the fifth nose 5.

[0058]

The effects of the present invention are as follows.

According to a first aspect of the present invention, there is provided a camshaft for cam-engaging a valve to rotate the valve in accordance with rotation about the axis, and the camshaft is located on the axis. A shaft body, a low cam nose fixed to the cam shaft body and cam-engaged with the valve, a high cam nose disposed adjacent to the low cam nose in the axial direction of the cam shaft body, The high cam nose protrudes toward the outside in the radial direction from the low cam nose cam protruding end. The operation of an internal combustion engine comprising: a support means for supporting the high cam nose; and a locking means capable of engaging and disengaging the high cam nose with the camshaft body when the high cam nose is moved forward. In the mechanism,

With the rotation of the camshaft, the high cam nose is engaged with the valve to be moved forward and / or backward.

For this reason, in order to move the high cam nose forward and backward, a hydraulic means and a spring are conventionally provided. However, the engagement with the valve causes the high cam nose to move. The hydraulic means and the spring are not required.

Therefore, the number of parts of the variable valve lift device in the valve mechanism of the internal combustion engine is reduced, and the configuration is simplified.

According to a second aspect of the present invention, the bearing means comprises a pair of bearing bodies supported by the camshaft main body and spaced apart from each other across the axis in the forward and backward movement directions of the high cam nose. A pair of bearings formed in the high cam nose and arranged so as to sandwich the bearings from the respective radially outer sides of the camshaft main body so as to be slidable against the bearings in the forward and backward movement directions, respectively. Sliding surface.

For this reason, the high cam nose is supported by a pair of support members which are largely separated from each other with the shaft center interposed therebetween. Therefore, when the high cam nose moves forward and backward, the center axis of the high cam nose moves relative to the support member. The high cam nose is smoothly moved.

Therefore, the external force for moving the high cam nose forward and backward is small, and the structure of the valve lift variable device in the valve mechanism of the internal combustion engine is further simplified accordingly.

According to a third aspect of the present invention, each of the bearing members is formed in a circular shape when viewed from the line of sight along the axial direction of the camshaft body.

Therefore, as compared with the prior art in which the cross section of the bearing is rectangular, the bearing can be easily formed, that is, the variable valve lift device in the valve train of the internal combustion engine can be easily formed. Can be.

Further, since the surfaces of the bearings for slidingly contacting the sliding surfaces are arc surfaces, the movement of the high cam nose can be more smoothly performed.
The external force for moving the high cam nose forward and backward is small, and the configuration of the valve lift variable device in the valve mechanism of the internal combustion engine can be further simplified.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional side view when a high cam nose is in a “retracted state”.

FIG. 2 is a cross-sectional view of FIG. 1 viewed from a line of sight along an axis of a crankshaft.

FIG. 3 is an operation explanatory diagram when the high cam nose is moved forward.

FIG. 4 is an operation explanatory diagram when the high cam nose is moved backward.

FIG. 5 is a partial side sectional view when the high cam nose is in a “projecting state”.

FIG. 6 is a cross-sectional view of FIG. 5 viewed from a line of sight along the axis of the crankshaft.

FIG. 7 is a partial side sectional view when the high cam nose is locked.

FIG. 8 is a diagram showing a modification, and is a diagram corresponding to FIG. 5;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 internal combustion engine 5 valve 11 valve operating mechanism 12 shaft center 13 cam shaft 15 cam shaft main body 16 low cam nose 17 high cam nose 18 cam protruding end 19 cam protruding end 20 support means 21 pushing means 22 locking means 24 support body 25 support body 26 Sliding contact surface 27 Sliding contact surface 35 End 43 End A Forward movement B Reverse movement X Forward and backward movement directions

Claims (3)

[Claims] 1. A camshaft for cam-engaging a valve to open and close the valve in accordance with rotation about the axis, the camshaft being a camshaft main body located on the axis, A low cam nose fixed to the camshaft main body and cam-engaged with the valve, a high cam nose arranged adjacent to the low cam nose in the axial direction of the camshaft main body, and a radially outward of the camshaft main body. The cam protruding end of the high cam nose protrudes from the cam protruding end of the low cam nose, so that the high cam nose can be moved forward and backward so that it can be retracted, and the high cam nose is supported on the cam shaft body. A valve operating mechanism for an internal combustion engine, comprising: a supporting means for allowing the high cam nose to move forward and backward; and a locking means for enabling the high cam nose to be removably locked to the camshaft main body. Serial with the rotation of the camshaft, the high cam nose engages with the forward movement and / or the valve lift amount variable device in a valve operating mechanism for an internal combustion engine to be allowed to recover moved to the valve. 2. The high cam nose, wherein the bearing means is supported by the camshaft main body, and is formed on the high cam nose. And a pair of sliding contact surfaces which are arranged so as to sandwich the bearings from the respective radially outer sides of the camshaft main body, and which are slidable with respect to the bearings in the forward and backward movement directions, respectively. The variable valve lift device in the valve train of an internal combustion engine according to claim 1, further comprising: 3. The valve lift variable device in the valve train of an internal combustion engine according to claim 2, wherein each of the bearings is circular when viewed in a line of sight along the axial direction of the camshaft main body.