JPH0996206A - Valve system mechanism of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve in productive capacity by means of possibility of continuous change in valve lift and valve timing by one sort of cam profile by forcing a valve which is on the way of releasing action to make its blocking action response to the running condition of an internal combustion engine. SOLUTION: Main rocker arms 36, 98 for driving valves 16, 78 and auxiliary rocker arms 38, 100 driven by cams 32, 94 are supported on the same rocker shafts 34, 96 while neighboring each other. A linking means for connecting/ releasing main rocker arms 36, 98 to/from auxiliary rocker arms 38, 100 is provided. This linking means connects the main rocker arms 36, 98 to the auxiliary rocker arms 38, 100 both for placing valves 16, 78 in their opening actions. And connection between main rocker arms 36, 98 and the auxiliary rocker arms 38, 100 is released by means of the rotation of rocker shafts 34, 96 for placing valves 16, 78 on the way of opening action according to the running condition of the internal combustion engine. Thereby, valve lift and valve timing can be changed continuously by means of one sort of cam profile.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve operating mechanism of an internal combustion engine, and more particularly, to a valve lift and valve timing which can continuously change valve lift and valve timing, and which is optimum according to the operating state of the internal combustion engine. Can be realized,
The present invention relates to a valve operating mechanism of an internal combustion engine that can change valve lift and valve timing with one cam profile and improve productivity.

[0002]

2. Description of the Related Art Some internal combustion engines of vehicles are provided with a valve operating mechanism for varying valve lift and valve timing of intake / exhaust valves in order to improve various required functions.

As an example of such a valve mechanism, there is a cam profile switching type. In this cam profile switching type valve mechanism, for example, two types of low speed cams and medium and high speed cams are provided on the cam shaft, and two types of low speed rocker arms and medium and high speed rocker arms are provided.

In this valve operating mechanism, the low speed cam rocks the low speed rocker arm, while the medium high speed cam rocks the medium high speed rocker arm, and the low speed rocker arm opens and closes the intake and exhaust valves at low speeds. on the other hand,
The intake / exhaust valves are opened / closed by the rocker arm for medium / high speed during middle / high speed.

As a valve mechanism for such an internal combustion engine,
For example, JP-A-61-11071, JP-A-61-1
There are those disclosed in Japanese Patent No. 51419 and Japanese Patent Laid-Open No. 1-83111.

In the valve mechanism disclosed in Japanese Unexamined Patent Publication No. 61-17107, a rocker arm that operates a valve and a free cam follower that is operated by a cam are rotatably arranged side by side on a common shaft. Holes corresponding to the free cam followers are formed respectively, and a pin inserted into the holes is moved to selectively connect or disconnect the rocker arm and the free cam follower.

The valve mechanism disclosed in Japanese Patent Laid-Open No. 61-51419 has two arm members pivotally supported by a common shaft between a cam and a valve lifter, and one arm member is a cam. The other arm member is engaged, and the other arm member is engaged with the valve lifter. Two arm members are provided so as to be disengageable by a pin, and the pin is arranged at a position substantially in line with the valve lifter.

In the valve mechanism disclosed in Japanese Patent Laid-Open No. 1-83111, a switching pin that is slidably fitted to one of the two cam followers adjacent to each other and is also fitted to the other is provided. , A regulating pin which is coaxially abutted on the switching pin and slidably fitted to the other cam follower is provided.
In the case where a return spring for urging the regulation pin toward one cam follower side is provided, a guide hole for slidably fitting the regulation pin is provided in the other cam follower, and the regulation pin is provided to accommodate the return spring inside. The bottom is formed in a cylindrical shape, and a retaining ring for preventing the restriction pin from being pulled out from the guide hole is fitted on the inner surface of the guide hole.

[0009]

However, the conventional valve train for an internal combustion engine has a problem that the pattern of valve lift and valve timing is determined by the number of cam profiles provided. For example, in a valve mechanism having two types of cam profiles, a low speed cam and a medium and high speed cam, there is a problem that only two patterns of valve lift and valve timing can be obtained.

Therefore, in order to obtain n kinds of valve lifts and valve timings, n rocker arms and cam profiles are required, and as many cam profiles and rocker arms as necessary valve lifts and valve timings are required. Since it becomes necessary, there is an inconvenience that productivity is poor.

In practice, due to the space limitation of the valve operating chamber, only two stages of variable valve lift and variable valve timing can be obtained, and optimum valve lift and valve timing that improve performance in a wide range of operating conditions can be obtained. There was an inconvenience that it was not possible.

[0012]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention provides a valve for opening and closing a port communicating with a combustion chamber of a cylinder head of an internal combustion engine, and a stem of the valve has one end side. A main rocker arm whose other end is pivotally supported by the rocker shaft, one end side of which is slidably contacted by the cam of the cam shaft and the other end of which is pivotally supported by the rocker shaft. An auxiliary rocker arm is provided, the main rocker arm and the auxiliary rocker arm are connected to open the valve, and the main rocker arm and the auxiliary rocker arm are closed to open the valve during the opening operation according to the operating state of the internal combustion engine. Interlocking means for releasing the connection of the locker shaft by the rotation of the rocker shaft is provided.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the valve mechanism of the present invention, a main rocker arm that drives a valve and a sub rocker arm that is driven by a cam are adjacently pivotally supported on the same rocker shaft, and the main rocker arm and the sub rocker arm are connected / released. The interlocking means is provided. The interlocking means connects the main rocker arm and the sub rocker arm so as to open the valve, and
The main rocker arm and the sub rocker arm are disconnected from each other by the rotation of the rocker shaft so as to close the valve during the opening operation according to the operating state of the internal combustion engine.

Thus, the valve operating mechanism closes the valve in the middle of the opening operation according to the operating state of the internal combustion engine, thereby eliminating the need for a large number of cam profiles and using one type of cam profile. The valve lift and the valve timing (close side) can be continuously changed, and the valve lift and the valve timing that change over a wide range can be obtained.

[0015]

An embodiment of the present invention will be described below with reference to the drawings. 1 to 16 show an embodiment of the present invention. 1 and 2, 2 is an internal combustion engine, 4 is a cylinder head, 6 is a combustion chamber, 8 is an intake port, and 10 is an exhaust port. The internal combustion engine 2 is provided with an intake system valve mechanism 12A and an exhaust system valve mechanism 12B as a valve mechanism 12 that opens and closes the intake port 8 and the exhaust port 10.

The intake system valve mechanism 12A has an intake valve seat 14 attached to the end of the intake port 8 on the side of the combustion chamber 6, and an intake valve 16 for opening and closing the intake port 8 supported by an intake valve guide 18 so as to be movable in the axial direction. Are provided. Intake valve 16
The intake stem 20 is supported by the intake valve seat 18 by opening and closing the intake port 8 by bringing the intake umbrella portion 20 into and out of contact with the intake valve seat 14.

The intake stem 22 of the intake valve 16 includes an intake spring receiving portion 24 near the opposite end of the intake umbrella portion 20.
And an intake rocker arm contact portion 26 is provided at the opposite end. Intake spring receiving portion 24 and cylinder head 4
An intake spring 28 for urging the intake valve 16 in the closing direction is attached between the and.

In the intake system valve mechanism 12A, an intake cam 32 is provided on an intake cam shaft 30 which is axially supported on the cylinder head 4, an intake rocker shaft 34 is provided on the cylinder head 4, and an intake stem of the intake valve 16 is provided. An intake main rocker arm 36, one end of which is abutted against the intake rocker arm abutting portion 26 of 22 and the other end of which is pivotally supported by an intake rocker shaft 34.
An intake sub-rocker arm 38 is provided adjacent to the intake main rocker arm 36, one end side of which is slidably contacted with the intake cam 32 of the intake cam shaft 30 and the other end side of which is pivotally supported by the intake rocker shaft 34. There is.

As shown in FIGS. 3 to 6, the intake main rocker arm 36 is provided with a cylindrical main intake shaft support 40 which is axially supported by the intake rocker shaft 34.
At 0, a main contact portion 42 for the intake stem, which abuts on the intake rocker arm contact portion 26, is provided in a protruding manner.

The intake main shaft support portion 40 is provided with a cylindrical intake main support portion 44 which is smaller in diameter than the intake main shaft support portion 40 and which is mounted on the intake rocker shaft 34 so as to project coaxially. The intake main support portion 44 includes the intake fitting hole 4
6 is formed in the diameter direction.

An intake main extension 48 is provided on the intake main shaft support 40 on the side opposite to the intake stem main contact portion 42. An intake cushioning portion 52 of an intake cushioning mechanism 50 attached to the cylinder head 4 is pushed and abutted against the intake main extension portion 48. The intake cushioning mechanism 50 is actuated by hydraulic pressure to push the intake cushioning section 52 to reduce the returning speed of the intake main rocker arm 36 by the intake spring 28, thereby reducing the intake valve 1
The shock caused by the abrupt contact between the intake umbrella portion 20 of 6 and the intake valve seat 14 is mitigated.

As shown in FIGS. 3 to 6, the intake auxiliary rocker arm 38 is provided with a cylindrical auxiliary intake shaft support portion 54 which is axially supported by the intake main support portion 44 of the intake main rocker arm 36.
An intake cam auxiliary sliding contact portion 56, which is in sliding contact with the intake cam 32, is provided on the intake auxiliary shaft support portion 54 in a protruding manner.

The intake system valve operating mechanism 12A includes an intake valve 16
The intake main rocker arm 36 and the intake sub-rocker arm 38 are connected to each other so as to open, and the intake main rocker arm 36 and the intake sub-rocker arm 38 are connected to close the intake valve 16 in the opening operation according to the operating state of the internal combustion engine 2. An intake interlocking means 58 for releasing the intake air by rocking the intake rocker shaft 34 is provided.

The intake interlocking means 58 is an auxiliary sliding contact portion 5 for the intake cam provided on the intake auxiliary shaft support portion 54 of the intake auxiliary rocker arm 38.
6, an intake sub-accommodating section 60 is provided on the opposite side, and an intake interlocking member 62 is provided in the intake sub-accommodating section 60.
It is accommodated so as to be slidable toward the intake main support portion 44.
The intake interlocking member 62 is elastically biased toward the intake main support portion 44 by the intake interlocking spring 64.

The intake interlocking member 62 is provided with an intake pin portion 66 and an intake claw portion 68. The intake pin portion 66 is provided so as to protrude toward the intake main support portion 44 so as to be fitted into the intake fitting hole 46 formed in the intake main support portion 44. The intake claw portion 68 is located outside the intake auxiliary shaft support portion 54 and faces the intake rocker shaft 34 side so that a force in a direction of removing the intake pin portion 66 from the intake fitting hole 46 is applied. It is provided so as to project.

Intake claw portion 6 of the intake rocker shaft 34
An intake cam portion 70 that engages with the intake pawl portion 68 and that exerts a force in a direction to remove the intake pin portion 66 from the intake fitting hole 46 is provided at a portion corresponding to 8.

As shown in FIG. 2, the intake rocker shaft 34 axially supported by the cylinder head 4 has one end projected outside the cylinder head 4, and is connected to an intake drive unit 74 such as a step motor by an intake gear train 72. Have been contacted. The intake drive section 74 is connected to a control means (not shown) and is driven so as to change the engagement timing of the intake cam section 70 with respect to the intake pawl section 68 in accordance with the operating state of the internal combustion engine 2 (engine speed, engine load, etc.). Then, the intake rocker shaft 34 is rotated.

As shown in FIGS. 9 to 11, the intake interlocking member 62 has the intake pin portion 66 fitted in the intake fitting hole 46 of the intake main rocker arm 36, and the intake sub rocker arm 3
When 8 rotates with respect to the intake rocker shaft 34,
When the intake pawl portion 68 does not engage with the intake cam portion 70, no force is applied in the direction of removing the intake pin portion 66 from the intake fitting hole 46, and the intake main rocker arm 36 and the intake sub rocker arm 38 are connected. As a result, the intake valve 16 is opened.

The intake interlocking member 62 is shown in FIGS.
4, the intake pin portion 66 is connected to the intake main rocker arm 3
When the intake sub-rocker arm 38 rotates with respect to the intake rocker shaft 34 in a state of being fitted in the intake fitting hole 46 of No. 6, when the intake pawl portion 68 engages with the intake cam portion 70,
A force is applied in a direction to pull the intake pin portion 66 out of the intake fitting hole 46, and the intake main rocker arm 36 and the intake sub rocker arm 38 are released from the intake valve 1 during the opening operation.
6 is closed.

On the other hand, the exhaust system valve mechanism 12B has the same structure as the intake system valve mechanism 12A. That is,
In the exhaust system valve mechanism 12B, an exhaust valve seat 76 is attached to the end of the exhaust port 10 on the side of the combustion chamber 6, and an exhaust valve 78 for opening and closing the exhaust port 10 is supported by an exhaust valve guide 80 so as to be movable in the axial direction. There is. The exhaust valve 78 opens and closes the exhaust port 10 by bringing the exhaust umbrella portion 82 into and out of contact with the exhaust valve seat 76, and the exhaust stem 84 is supported by the exhaust valve guide 80.

On the exhaust stem 84 of the exhaust valve 78, an exhaust spring receiving portion 86 is provided near the opposite end of the exhaust umbrella portion 82.
And an exhaust rocker arm contact portion 88 is provided at the opposite end. Exhaust spring receiving portion 86 and cylinder head 4
An exhaust spring 90 for urging the exhaust valve 78 in the closing direction is attached between the and.

The exhaust system valve mechanism 12A is provided with an exhaust cam 94 on an exhaust cam shaft 92 axially supported on the cylinder head 4, an exhaust rocker shaft 96 axially supported on the cylinder head 4, and an exhaust stem of an exhaust valve 78. An exhaust main rocker arm 98 whose one end is abutted against the exhaust rocker arm abutting portion 88 of 84 and whose other end is pivotally supported by an exhaust rocker shaft 96.
An exhaust sub-rocker arm 100 is provided adjacent to the exhaust main rocker arm 98, one end side of which is in sliding contact with the exhaust cam 94 of the exhaust cam shaft 92 and the other end side of which is pivotally supported by the exhaust rocker shaft 96. There is.

As shown in FIGS. 7 to 8, the exhaust main rocker arm 98 is provided with a cylindrical exhaust main shaft support portion 102 which is axially supported by the exhaust rocker shaft 96, and the exhaust main rocker arm contact portion 102 is provided with the exhaust rocker arm contact portion. An exhaust stem main abutting portion 104 that abuts 88 is projected.

The exhaust main shaft support portion 102 is provided with a cylindrical main exhaust support portion 106 which is smaller in diameter than the exhaust main shaft support portion 102 and which is mounted on the exhaust rocker shaft 96 so as to project coaxially. An exhaust fitting hole 108 is formed in the exhaust main support portion 106 in the diameter direction.

On the exhaust main shaft support 102, an exhaust main extension 110 is provided on the opposite side of the main exhaust stem abutment 104. In the exhaust main extension 110, the cylinder head 4
Exhaust buffer section 114 of exhaust buffer mechanism 112 attached to
Is pushed and abutted.

The exhaust cushioning mechanism 112 is actuated by hydraulic pressure to push the exhaust cushioning portion 114 to move, and the exhaust spring 9
The return speed of the exhaust main rocker arm 98 by 0 is reduced, and the exhaust umbrella portion 82 of the exhaust valve 78 and the exhaust valve seat 76 are reduced.
Alleviates the impact of sudden contact with.

The exhaust auxiliary rocker arm 100 is provided with a cylindrical exhaust auxiliary shaft support portion 116 which is axially supported by the exhaust main support portion 106 of the exhaust main rocker arm 98, and the exhaust cam 94 is slidably contacted with the exhaust auxiliary shaft support portion 116. A secondary sliding contact portion 118 for the exhaust cam is provided so as to project.

The exhaust system valve mechanism 12A includes an exhaust valve 78.
The exhaust main rocker arm 98 and the exhaust sub-rocker arm 100 are connected to each other so as to open the engine, and the exhaust main rocker arm 98 and the exhaust sub-rocker arm 100 are connected to close the exhaust valve 78 in the opening operation according to the operating state of the internal combustion engine 2. An exhaust interlocking device 120 for releasing the exhaust gas by rotating the exhaust rocker shaft 96 is provided.

The exhaust interlocking means 120 is provided with an exhaust sub-accommodating portion 122 on the side opposite to the exhaust cam auxiliary sliding contact portion 118 provided on the exhaust auxiliary shaft support portion 116 of the exhaust auxiliary rocker arm 100. The exhaust interlocking member 124 is slidably housed in the main exhaust rocker arm 98 toward the main exhaust support portion 106. The exhaust interlocking member 124 is elastically biased toward the exhaust main support portion 106 by the exhaust interlocking spring 126.

The exhaust interlocking member 124 is provided with an exhaust pin portion 128 and an exhaust claw portion 130. Exhaust pin part 1
Reference numeral 28 denotes an exhaust fitting hole 1 formed in the exhaust main support portion 106.
It is provided so as to project toward the exhaust main support portion 106 side so as to be fitted to the 08. The exhaust claw portion 130 is positioned outside the exhaust auxiliary shaft support portion 116 and faces the exhaust rocker shaft 96 side so that a force in a direction of pulling out the exhaust pin portion 128 from the exhaust fitting hole 108 is applied. It is provided so as to project.

Exhaust claw 1 of the exhaust rocker shaft 96
An exhaust cam portion 132 that engages with the exhaust claw portion 130 and that exerts a force in a direction to remove the exhaust pin portion 128 from the exhaust fitting hole 108 is provided at a portion corresponding to 30.

As shown in FIG. 2, the exhaust rocker shaft 96 pivotally supported by the cylinder head 4 has one end projecting outside the cylinder head 4, and the exhaust gear train 134 causes the exhaust drive unit 136 such as a step motor to operate. Have been contacted. The exhaust drive unit 136 is connected to a control unit (not shown), and the operating state of the internal combustion engine 2 (engine speed, engine load, etc.).
The exhaust rocker shaft 96 is driven to rotate so as to change the engagement timing of the exhaust cam portion 132 with the exhaust claw portion 130 in accordance with the above.

The exhaust interlocking member 124 has an exhaust pin portion 128.
When the auxiliary exhaust rocker arm 100 rotates with respect to the exhaust rocker shaft 96 with the exhaust main rocker arm 98 fitted in the exhaust fitting hole 108, the exhaust pawl portion 130 must engage the exhaust cam portion 132. , A force in the direction of pulling out the exhaust pin portion 128 from the exhaust fitting hole 108 is not applied, and the exhaust main rocker arm 98 and the exhaust sub rocker arm 1
The exhaust valve 78 is opened in a state where 00 is connected.

The exhaust interlocking member 124 is provided when the exhaust auxiliary rocker arm 100 rotates with respect to the exhaust rocker shaft 96 with the exhaust pin portion 128 fitted in the exhaust fitting hole 108 of the exhaust main rocker arm 98. When the exhaust pawl portion 130 engages with the exhaust cam portion 132, the exhaust pin portion 12
8 is pulled out from the exhaust fitting hole 108, and the main exhaust rocker arm 98 and the auxiliary exhaust rocker arm 1 are attached.
Then, the exhaust valve 78 in the middle of the opening operation is closed.

In this way, the intake interlocking means 58 of the intake system valve mechanism 12A and the exhaust interlocking means 1 of the exhaust system valve mechanism 12B.
20 has the same configuration and operates in the same manner. Therefore, in the following operation, the intake system valve mechanism 12A will be described.

Next, the operation of this embodiment will be described.

When the intake system valve mechanism 12A obtains a valve lift (valve lift amount H) according to the cam profile of the intake cam 32 as shown in FIG. It is operated as shown.

The intake interlocking means 58 has an intake cam portion 70 at a swing angle θ1 (θ1> θ2) larger than the swing angle θ2 of the intake auxiliary rocker arm 38 when the valve lift amount H is obtained.
The intake rocker shaft 34 is rotated by the intake drive unit 74 so that the position is positioned.

The intake interlocking means 58, as shown in FIGS. 9 and 10, has the auxiliary sliding contact portion 5 for the intake cam of the intake auxiliary rocker arm 38.
When the base circle part of the intake cam 32 is in sliding contact with the intake cam 32, the intake pin portion 66 of the intake interlocking member 62 pushed by the intake interlocking spring 64 is attached to the intake main rocker arm 3
6 is fitted in the intake fitting hole 46. As a result, the intake main rocker arm 36 is connected to and interlocks with the intake sub rocker arm 38.

In the intake sub-rocker arm 38 connected to the intake main rocker arm 36, the protruding portion of the intake cam 32 is rotated by the rotation of the intake cam shaft 30 so that the intake cam sub-sliding contact portion 56.
When slidably contacted with, the intake cam 32 pushes and swings. As a result, the intake main rocker arm 36 is swung together with the intake sub rocker arm 38 to open the intake valve 16.

As shown in FIG. 11, when the maximum protruding portion of the intake cam 32 is brought into sliding contact with the auxiliary slide contact portion 56 for intake cam, the intake auxiliary rocker arm 38 is pushed by the intake cam 32 and has the maximum swing angle. It is swung to θ2.

At this time, since the intake cam portion 70 of the intake rocker shaft 34 is positioned at a swing angle θ1 (θ1> θ2) outside the swing angle θ2 of the auxiliary intake rocker arm 38, the intake interlocking member 62 of the intake interlocking member 62 is prevented. The intake claw portion 68 is the intake cam portion 70.
Will not be engaged.

Therefore, the intake interlocking member 62 releases the connection between the intake main rocker arm 36 and the intake sub-rocker arm 38 without being applied with a force in the direction of withdrawing the intake pin portion 66 from the intake fitting hole 46. Without doing so, the intake valve 16 is opened in the connected state.

As a result, the intake valve 16 has a valve lift according to the cam profile as shown in FIG. 15, and the valve lift amount H can be obtained.

The intake system valve mechanism 12A is operated as shown in FIGS. 12 to 14 when the valve lift amount H / 2 as shown in FIG. 16 is obtained depending on the operating state of the internal combustion engine 2.

The intake interlocking means 58 has a valve lift amount H /
Swing angle θ of the intake sub rocker arm 38 when 2 is obtained
3, the intake rocker shaft 34 is rotated by the intake drive unit 74 by an angle (θ1−θ3) obtained by subtracting the swing angle θ3 from the swing angle θ1.

The intake interlocking means 58, as shown in FIG.
When the base circle portion of the intake cam 32 is in sliding contact with the auxiliary sliding contact portion 56 for the intake cam of the auxiliary intake rocker arm 38, the intake pin portion 66 of the intake interlocking member 62 pushed by the intake interlocking spring 64 is the main intake The rocker arm 36 is fitted into the intake fitting hole 46. As a result, the intake main rocker arm 36 is connected to and interlocks with the intake sub rocker arm 38. At this time, the intake pin portion 66 is fitted in the intake fitting hole 46 of the intake main rocker arm 36 by x.

In the intake auxiliary rocker arm 38 connected to the intake main rocker arm 36, the protruding portion of the intake cam 32 is rotated by the rotation of the intake cam shaft 30 so that the intake cam auxiliary slide contact portion 56 is formed.
When slidably contacted with, the intake cam 32 pushes and swings. As a result, the intake main rocker arm 36 is swung together with the intake sub rocker arm 38 to open the intake valve 16.

The intake sub rocker arm 38 is shown in FIGS.
As shown in FIG. 4, before the maximum protruding portion of the intake cam 32 is slidably contacted with the intake cam auxiliary sliding contact portion 56, it is pushed by the intake cam 32 and swung up to the swing angle θ3.

The intake auxiliary rocker arm 38 swung to the swing angle θ3 has the intake claw portion 68 of the intake interlocking member 62 because the intake cam portion 70 of the intake rocker shaft 34 is positioned at the swing angle θ3. The intake cam portion 70 is engaged.

When the intake pawl portion 68 of the intake interlocking member 62 is pushed by the intake cam 32 and the intake sub-rocker arm 38 tries to swing further from the swing angle θ3, the intake pawl portion 70 of the intake rocker shaft 34 receives the intake pawl portion. The portion 68 rides up, and a force is applied to the intake claw portion 68 in a direction to pull it out of the intake fitting hole 46.

Therefore, the intake interlocking member 62 releases the connection between the intake main rocker arm 36 and the intake sub-rocker arm 38 by applying a force in the direction of removing the intake pin portion 66 from the intake fitting hole 46. Then, the intake valve 16 in the middle of the opening operation is closed at the valve lift amount H / 2.

As a result, the intake valve 16 can obtain the valve lift amount H as shown in FIG.

Intake sub-rocker arm 38 disconnected
Is pushed by the intake cam 32 and swung according to the cam profile. On the other hand, the intake main rocker arm 36 that has been disconnected is closed by the intake spring 28.

Intake valve 16 closed during the opening operation
Is reduced by the intake cushioning portion 52 of the intake cushioning mechanism 50 to reduce the return speed of the intake main rocker arm 36 by the intake spring 28, thereby alleviating the impact caused by the sudden contact between the intake umbrella portion 20 and the intake valve seat 14. can do.

As shown in FIG. 12, when the intake cam 32 is further rotated and the base circle portion of the intake cam 32 slides again on the auxiliary slide contact portion 56 for the intake cam, the intake sub rocker arm 38 swings at the swing angle θ3. When the intake claw portion 68 of the intake interlocking member 62 is swung below, the engagement with the intake cam portion 70 is released.

As a result, the intake sub rocker arm 38 is
The intake pin portion 66 of the intake interlocking member 62 pushed by the intake interlocking spring 64 is fitted into the intake fitting hole 46 of the intake main rocker arm 36, and the intake main rocker arm 36 is connected to the intake sub-rocker arm 38. Swing angle θ
It will be linked up to 3.

As described above, the intake system valve mechanism 12A pivotally supports the intake main rocker arm 36 for driving the intake valve 16 and the intake sub-rocker arm 38 driven by the intake cam 32 adjacent to the same intake rocker shaft 34. An intake interlocking device 58 for connecting / disconnecting the intake main rocker arm 36 and the intake sub rocker arm 38 is provided.

The intake interlocking means 58 connects the intake main rocker arm 36 and the intake sub-rocker arm 38 to open the intake valve 16, and closes the intake valve 16 during the opening operation according to the operating state of the internal combustion engine 2. As a result, the intake main rocker arm 36 and the intake sub rocker arm 38 are disconnected by the rotation of the intake rocker shaft 34.

As a result, this intake system valve operating mechanism 12A
Since the intake valve 16 in the middle of the opening operation can be closed according to the operating state of the internal combustion engine 2, the valve lift and the valve timing can be changed by one type of cam profile without requiring a large number of cam profiles. (Closed side) can be continuously changed, and a wide range of valve lift and valve timing can be obtained.

Therefore, the intake system valve operating mechanism 12A is
Since the valve lift and the valve timing can be continuously changed, the optimum valve lift and the valve timing can be realized according to the operating state of the internal combustion engine 2, and the performance of the internal combustion engine 2 can be improved. . In addition, since the intake system valve mechanism 12A can change the valve lift and the valve timing with one cam profile, the productivity can be improved.

The exhaust interlocking device 120 of the exhaust system valve operating mechanism 12B is operated similarly to the intake interlocking device 58 of the intake system valve operating mechanism 12A. As a result, the exhaust valve 78
As for the above, the valve lift and the valve timing (closing side) can be continuously changed by one type of cam profile without requiring a large number of cam profiles as described above, and the valve can be changed over a wide range. Lift and valve timing can be obtained, and similar effects can be obtained.

[0073]

As described above, the valve operating mechanism of the internal combustion engine according to the present invention closes the valve in the middle of the opening operation according to the operating state of the internal combustion engine, thereby eliminating the need for a large number of cam profiles. With one type of cam profile, the valve lift and the valve timing (close side) can be continuously changed, and the valve lift and the valve timing that change over a wide range can be obtained.

Therefore, this valve operating mechanism can continuously change the valve lift and the valve timing to realize the optimum valve lift and the valve timing according to the operating state of the internal combustion engine. The performance can be improved, and the valve lift and the valve timing can be changed with one cam profile, so that the productivity can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a cylinder head of an internal combustion engine provided with a valve mechanism according to an embodiment of the present invention.

FIG. 2 is a plan view of the cylinder head of FIG.

FIG. 3 is a plan view of an intake valve operating mechanism.

FIG. 4 is a cross-sectional explanatory view of a connection state of an intake main rocker arm and an auxiliary rocker arm.

FIG. 5 is a partially cutaway perspective view of an intake system valve mechanism.

FIG. 6 is a partially cutaway assembly view of the intake valve operating mechanism.

FIG. 7 is a partially cutaway perspective view of an exhaust system valve mechanism.

FIG. 8 is a partially broken assembly view of an exhaust system valve mechanism.

FIG. 9 is a partially cutaway plan view of the connection state of the intake main rocker arm and the intake sub rocker arm during the base circle.

FIG. 10 is a cross-sectional explanatory view of a connected state of the intake main rocker arm and the intake sub rocker arm during the base circle.

FIG. 11 is a cross-sectional explanatory view of a connected state of the intake main rocker arm and the intake sub rocker arm during a lift.

FIG. 12 is an explanatory cross-sectional view of a connected state of the intake main rocker arm and the intake sub rocker arm during the base circle.

FIG. 13 is a partially cutaway plan view of a connection state of the intake main rocker arm and the intake sub rocker arm during a lift.

FIG. 14 is a cross-sectional explanatory view of a state in which the intake main rocker arm and the intake sub rocker arm are disconnected from each other during a lift.

FIG. 15 is a diagram showing a valve lift according to a cam profile when a valve lift amount H is obtained.

FIG. 16 is a diagram showing a valve lift when a valve lift amount H / 2 is obtained.

[Explanation of symbols]

 2 Internal combustion engine 4 Cylinder head 6 Combustion chamber 8 Intake port 10 Exhaust port 12 Valve mechanism 12A Intake system valve mechanism 12B Exhaust system valve mechanism 16 Intake valve 22 Intake stem 30 Intake camshaft 32 Intake cam 34 Intake rocker shaft 36 Intake Main rocker arm 38 Intake sub rocker arm 42 Main contact part for intake stem 46 Intake fitting hole 50 Intake cushioning mechanism 56 Secondary slide contact part for intake cam 58 Intake interlocking device 62 Intake interlocking member 66 Intake pin part 68 Intake claw part 70 Intake cam Part 72 Intake gear train 74 Intake drive part 78 Exhaust valve 96 Exhaust rocker shaft 98 Exhaust main rocker arm 100 Exhaust auxiliary rocker arm 112 Exhaust buffer mechanism 120 Exhaust interlocking device 124 Exhaust interlocking member 128 Exhaust pin part 130 Exhaust claw part 132 Exhaust cam part 136 Exhaust Drive part

Claims (2)

[Claims] 1. A main rocker arm provided with a valve for opening and closing a port communicating with a combustion chamber of a cylinder head of an internal combustion engine, one end of which is in contact with a stem of the valve and the other end of which is pivotally supported by a rocker shaft. Adjacent to this main rocker arm, one end side is slidably contacted with the cam of the cam shaft, and the other end side is pivotally supported by the rocker shaft. A sub rocker arm is provided, and the main rocker arm and the sub rocker arm are opened to open the valve. Interlocking means for connecting the rocker arm and releasing the connection of the main rocker arm and the sub rocker arm by the rotation of the rocker shaft so as to close the valve during the opening operation according to the operating state of the internal combustion engine. A valve mechanism for an internal combustion engine. 2. The interlocking means includes an interlocking member that is elastically biased toward the main rocker arm side on the sub-rocker arm, and the interlocking member has a pin portion that is fitted into a fitting hole of the main rocker arm. Is provided with a pawl portion to which a force is applied in the direction of pulling out the pin portion from the connection hole, and the rocker shaft is provided with a cam portion that engages with the pawl portion to apply the force, 2. The valve operating valve for an internal combustion engine according to claim 1, further comprising a drive unit for rotating the rocker shaft so as to change an engagement timing of the cam portion with respect to the pawl portion according to an operating state of the internal combustion engine. mechanism.