JPH0323722B2 - - Google Patents

Description

Detailed Description of the Invention A. Purpose of the Invention (1) Industrial Field of Application The present invention is directed to a camshaft which is rotatably driven in synchronization with the rotation of an engine, and which includes a pair of intake valves or The present invention relates to a valve operating system for a multi-cylinder internal combustion engine, in which a cam is integrated in correspondence with an exhaust valve, and the cam is interlocked with the cam via a valve driving member to open and close both the intake valves or the exhaust valve.

(2) Prior art Conventionally, in an internal combustion engine in which a plurality of intake valves or exhaust valves are arranged for one cylinder, some of the intake valves or exhaust valves are deactivated during low-speed operation. It is disclosed in Publication No. 59-226216.

(3) Problems to be solved by the invention By the way, in a multi-cylinder internal combustion engine, in order to substantially nullify the work of a specific cylinder among the multiple cylinders, the opening/closing operation of the intake valve or exhaust valve of that specific cylinder is suspended. If it were possible to do so, it would be possible to reduce fuel consumption by suspending the operation of the intake valve or exhaust valve of a specific cylinder when the engine is operating at low speed. The necessary equipment was not available.

The present invention has been made in view of the above circumstances, and uses a relatively simple configuration to suspend the operation of the intake valve or exhaust valve of a specific cylinder, thereby reducing fuel consumption and reducing the need for low-speed and high-speed operation. It is an object of the present invention to provide a valve operating system for a multi-cylinder internal combustion engine that drives an intake valve or an exhaust valve at corresponding timing and lift amount.

B. Structure of the Invention (1) Means for Solving Problems According to the present invention, the camshaft for a specific cylinder includes a cam, and first and second perfectly circular camshafts corresponding to the base circle of the cam. a first valve driving member having a raised portion and slidingly in contact with the cam; and a second valve driving member that is individually connected to both the intake valves or the exhaust valve and that is individually connected in sliding contact with the first and second raised portions. The third valve drive member is arranged adjacent to the third valve drive member, and connection switching means capable of switching connection and disconnection between the two valve drive members are provided between the mutually adjacent valve drive members.

(2) Effect When the respective valve drive members are connected, the second and third valve drive members follow the first valve drive member operated by the cam.
A valve driving member opens and closes, and both intake valves or both exhaust valves open and close at a timing and lift amount determined by the cam. Furthermore, if the connections between the first and second valve drive members and between the first and third valve drive members are released, the second and third valve drive members will not open or close, and therefore both intake valves or both exhaust valves will not open or close. The valve remains inactive.

(3) Embodiments Below, embodiments of the present invention will be described with reference to the drawings. First, in FIGS. 1 and 2 showing an embodiment of the present invention, each cylinder of a multi-cylinder internal combustion engine has a pair of intake valves 1a. , 1b are provided, and these intake valves 1a, 1b are opened and closed by a cam 5 integrally provided with a camshaft 2 that is driven at a rotation ratio of 1/2 in synchronization with the rotation of the engine. Driven. Furthermore, in a specific cylinder, the first and second perfectly circular raised portions 3a and 3b adjacent to the cam 5 are integrated into the camshaft 2, and when the engine is operated at low speed, both raised portions 3a and 3b act as a Intake valve 1
The operations of a and 1b are suspended.

Hereinafter, only the configuration of the valve train in the specific cylinder will be described.

The camshaft 2 is rotatably disposed above the engine body, and the cam 5 is integrally provided on the camshaft 2 at a position corresponding to the middle of the intake valves 1a, 1b. Also, the first and second raised portions 3a, 3
b are arranged on both sides of the cam 5. Moreover, the cam 5 has a high portion 5a projecting radially outward from the base circle 5b, and the first and second raised portions 3a, 3b are formed in a perfect circular shape corresponding to the base circle 5b.

The rocker shaft 6 is fixedly arranged below the camshaft 2. This locking shaft 6 includes a first locking arm 7 as a first valve driving member corresponding to the cam 5, and first and second raised portions 3.
Second and third rocker arms 8a, 8b as second and third valve driving members corresponding to the valves a, 3b are pivotally supported, and a cam 5 and a first and third rocker arm 8a, 8b are mounted on the upper part of each rocker arm 7, 8a, 8b. 2 ridges 3
cam slippers 10, 11a, which are in sliding contact with a, 3b;
11b are provided respectively. Further, the second and third rocker arms 8a, 8b are connected to each intake valve 1a, 1b.
and at their tips each intake valve 1
Tappet screw 12 that can come into contact with the upper ends of a and 1b,
13 is screwed so that it can move forward and backward.

On the other hand, a flange 1 is provided at the upper part of both intake valves 1a and 1b.
4, 15 are provided, and these collar parts 14,
Valve springs 16 and 17 surrounding the intake valves 1a and 1b are interposed between the intake valve 15 and the engine body, and the valve springs 16 and 17 cause each intake valve 1a and 1b to move upward, that is, in the valve closing direction. energized.

In FIG. 3, a bottomed cylindrical lifter 19 is provided on the lower surface of the end of the first rocker arm 7 as a pressing means.
The lifter 19 is urged upward by a lifter spring 20 interposed between the lifter 19 and the engine main body. As a result, the cam slipper 10 of the first rocker arm 7 is constantly brought into resilient sliding contact with the cam 5.
Moreover, the spring force of the lifter spring 20 is set to be relatively weak.

In FIG. 4, each rocker arm 7, 8a, 8
b are in sliding contact with each other, a connection switching means 21a is provided between the first and second rocker arms 7, 8a, and a connection switching means 21a is provided between the first and third rocker arms 7, 8b. A connection switching means 21b having the same structure is provided.

The connection switching means 21a includes a piston 23 that is movable between a position where the first and second rocker arms 7 and 8a are connected and a position where the connection is released, and a stopper 24 that restricts the movement of the piston 23.
and a spring 25 that biases the stopper 24 to move the piston 23 toward the disconnection position.

The first locking arm 7 has a second locking arm 8.
A first guide hole 26 is opened toward the a side and is bored parallel to the rock shaft 6.
A small diameter portion 28 is provided on the closed end side of the first guide hole 26 via a stepped portion 27 . 1st guide hole 2
6 is slidably fitted with a piston 23, and a hydraulic chamber 29 is defined between the piston 23 and the closed end of the first guide hole 26.

An oil passage 30 communicating with the hydraulic chamber 29 is bored in the first rocker arm 7, and an oil passage 31 communicating with a hydraulic pressure supply source (not shown) is bored in the rocker shaft 6. Further, both oil passages 30 and 31 are connected to each other via a communication hole 32 bored in the side wall of the rock shaft 6.
Communication is always maintained regardless of the swinging state of the first rocker arm 7.

The second rocker arm 8a has a first guide hole 26.
Correspondingly, a second guide hole 35 is formed which is open toward the first rocker arm 7 side, and the disk-shaped stopper 24 is slid into this second guide hole 35. A small diameter portion 37 is provided at the closed end side of the second guide hole 35 via a regulating step 36, and an insertion hole 38 coaxial with the small diameter portion 37 is bored at the closed end. Moreover, a guide rod 39 coaxially and integrally provided with the stopper 24 is inserted into the insertion hole 38.
Furthermore, a coiled spring 25 surrounding the guide rod 39 is interposed between the stopper 24 and the closed end of the second guide hole 35 .

The axial length of the piston 23 is such that when one end of the piston 23 comes into contact with the stepped portion 27, the other end is located between the first and second rocker arms 7, 8a, and the stopper 24 is placed against the regulating step 36. The setting is such that one end remains in the first guide hole 26 when the second guide hole 35 is entered until the contact is made.

The connection switching means 21b is connected to the connection switching means 21.
Since it has the same structure as that in b, a detailed explanation of its structure will be omitted, but the double connection switching means 2
1a and 21b share an oil passage 31. Therefore, both connection switching means 21a, 21b perform switching operations between connection and disconnection at the same time.

Next, the operation of this embodiment will be explained. When the engine is operating at low speed, as shown in FIG.
The connection between the rocker arms 7 and 8a and between the first and third rocker arms 7 and 8b is released. That is, when the hydraulic pressure in the hydraulic chamber 29 is released,
The stopper 24 moves toward the first rocker arm 7 due to the spring force of the spring 25, and the piston 23 moves to the step portion 27.
It is forced to retreat until it touches the. In this state, the contact surfaces of the piston 23 and the stopper 24 are
and the sliding contact surfaces of the second rocker arms 7, 8a and the sliding surfaces of the first and third rocker arms 7, 8b, so that the first and second rocker arms
The third rocker arms 7, 8a, and 8b are in sliding contact with each other and are capable of relative angular displacement.

In such a disconnected state, the second and third rocker arms 8a, 8b that are in sliding contact with the first and second raised parts 3a, 3b are arranged so that the first and second raised parts 3a, 3b are perfectly circular. Since the intake valves 1a and 1b are in a shape, they do not swing, and both intake valves 1a and 1b remain closed. At this time, the first rocker arm 7 swings in accordance with the rotation of the cam 5, but this swinging action
It does not affect the operation of a and 1b. Moreover, the first
Since the rocker arm 7 is only in sliding contact with the cam 5 due to the relatively weak spring force of the lifter spring 20, wear loss in the valve train can be suppressed to a low level.

In this manner, when the engine is operating at low speed, the intake valves 1a and 2b of the specific cylinders cease their operation and remain closed, thereby reducing fuel consumption.

When operating the engine at high speed, the connection switching means 21
a, 21b connect the first and second rocker arms 7, 8a and the first and third rocker arms 7, 8b, as shown in FIG. That is, by supplying hydraulic pressure to the hydraulic chamber 29, the piston 23 fits into the second guide hole 35 while pressing the stopper 24 against the spring force of the spring 25, and the stopper 24 presses against the regulating step 36. It will be done. In this state, the first, second and third rocker arms 7, 8a, 8b are prevented from relative rotation and swing integrally.

In this connected state, the second and third rocker arms follow the swinging motion of the first rocker arm 7 that is in sliding contact with the cam 5.
The rocker arms 8a and 8b swing, and both intake valves 1
a and 1b are opened and closed at the timing and lift amount determined by the cam 5.

FIG. 6 shows another embodiment of the invention, in which the first and second raised portions 3a, 3b are arranged adjacent to each other, and the second and third rocker arms 8a, 8b are also arranged adjacent to each other. placed adjacent to. Further, a cam 5 and a first rocker arm 7 are arranged adjacent to the first raised portion 3a and the second rocker arm 8a, respectively, and between the second and first rocker arms 8a and 7, and between the second and third rocker arms.
The locker arms 8a and 8b can be connected and disconnected, respectively. That is, the connection switching means 21a in the embodiments of FIGS. 1 to 5
A connection switching means (not shown) corresponding to the connection switching means 21b is provided between the second and first rocker arms 8a, 7, and a connection switching means (not shown) corresponding to the connection switching means 21b is provided between the second and third rocker arms 8a, 7. 8b.

Therefore, when the second and first locking arms 8a, 7 and the second and third locking arms 8a, 8b are disconnected from each other during low speed operation of the engine, the second and third locking arms 8a, 8
b is in sliding contact with both raised portions 3a, 3b, both intake valves 1a, 1b are inactive, and when the engine is running at high speed, between the second and first rocker arms 8a, 7,
and second and third rocker arms 8a, 8b
When the two are connected, the second and third
Since the rocker arms 8a and 8b are connected to the first rocker arm 7, the second and third rocker arms 8a and 8b follow the first rocker arm 7, which is rocked by the cam 5, and thereby both The intake valves 1a and 1b will open and close at the timing and lift amount determined by the cam 5,
The same functions and effects as in the above embodiment can be obtained.

In the above embodiments, a valve operating system relating to a pair of intake valves 1a and 1b has been described, but the present invention can also be implemented in relation to a pair of exhaust valves.

C. Effects of the Invention As described above, according to the present invention, the camshaft for a specific cylinder is provided with a cam, and first and second raised portions having a perfect circular shape corresponding to the base circle of the cam, a first valve driving member in sliding contact with the cam;
Second and third valve drive members are arranged adjacent to each other and are individually connected to both the intake valves or the exhaust valves and individually slide into contact with the first and second protrusions, and between the mutually adjacent valve drive members. are each provided with a connection switching means capable of switching connection and disconnection between the two, so that by disconnecting the adjacent valve drive members when the engine is operating at low speed, the second and third valve drive members can be connected to each other. does not operate to open or close, therefore it is possible to reduce fuel consumption by keeping both intake valves or both exhaust valves in a specific cylinder inactive, and also to connect adjacent valve drive members when the engine is running at high speed. By this, the second and third valve drive members are opened and closed following the first valve drive member operated by the cam, and both intake valves or both exhaust valves are opened and closed at the timing and lift amount determined by the cam. can operate.

[Brief explanation of the drawing]

1 to 5 show an embodiment of the present invention, in which FIG. 1 is a vertical side view and a sectional view taken along the line - in FIG. 2, FIG. 2 is a plan view of FIG. 1, 3 is a sectional view taken along the line shown in FIG. 2, FIG. 4 is a sectional view taken along the line of FIG. 2 is a plan view corresponding to FIG. 2 of another embodiment of the present invention. 1a, 1b...Intake valve, 2...Camshaft,
3a...first raised part, 3b...second raised part, 5...
...Cam, 5b... Base circle, 7... First rocker arm as first valve driving member, 8a... Second rocker arm as second valve driving member, 8b... Third
Third rocker arm as a valve drive member, 19...
Lifter as pressing means, 21a, 22b...connection switching means.

Claims (1)

[Scope of Claims] 1. A cam is integrated into a camshaft that is driven to rotate in synchronization with the rotation of the engine, corresponding to a pair of intake valves or exhaust valves arranged for each cylinder, and the cam is integrated with a cam that corresponds to a pair of intake or exhaust valves arranged for each cylinder. The intake valves or the exhaust valves are opened and closed in conjunction with each other via a driving member.
In a valve train for a multi-cylinder internal combustion engine, the camshaft in a specific cylinder is provided with a cam and first and second protrusions having a perfect circular shape corresponding to a base circle of the cam, A first valve driving member that is in sliding contact with each other, and second and third valve driving members that are individually connected to both the intake valves or the exhaust valves, and that are in sliding contact with the first and second raised portions, respectively, are arranged adjacent to each other. A valve operating system for a multi-cylinder internal combustion engine, characterized in that connection switching means capable of switching connection and disconnection between mutually adjacent valve drive members are provided respectively. 2. The valve operating system for a multi-cylinder internal combustion engine according to claim 1, wherein the first valve driving member is brought into contact with a pressing means for elastically biasing the cam. .