JPH086572B2 - Valve train for internal combustion engine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plurality of rocker arms including a rocker arm having one end interlockingly connected to a camshaft and the other end provided with a tappet clearance adjusting mechanism for contacting the engine valve. It is placed between the camshafts and penetrates the middle of the length of each rocker arm.
The present invention relates to a valve train for an internal combustion engine that is rockably supported by a rocker shaft.

[0002]

2. Description of the Related Art Conventionally, such a valve operating device is known from, for example, Japanese Patent Laid-Open No. 59-231120.

[0003]

SUMMARY OF THE INVENTION In such a valve gear,
The engine valve is opened / closed by the rocking motion of each rocker arm in response to the rotational motion of the camshaft. By the way, the applicant of the present invention provides a plurality of rocker arms with a connection switching mechanism that switches connection and disconnection of adjacent rocker arms according to the action of hydraulic pressure, and connects and disconnects the connection switching mechanisms to the operating state of the engine. Has already been proposed ( Japanese Patent Application Laid-Open No. 63-63119) by controlling the opening / closing operation mode of the engine valve in accordance with the operating state of the engine by controlling in accordance with
No. 57805 ), it is possible to reduce fuel consumption and improve engine output by applying such a connection switching mechanism to the valve operating system targeted by the present invention.

However, when the connection switching mechanism is provided on the rocker arm, the rocker arm is inevitably increased in size and weight due to the installation of the connection switching mechanism. There is a risk that the balance around the shaft will be lost and the valve jump rotation limit will be reduced, making it impossible to cope with high rotation and high output.

The present invention has been made in view of the above circumstances, and an internal combustion engine capable of coping with high engine rotation and high output by providing a connection switching mechanism by increasing the balance around the rocker shaft of the rocker arm. It is an object to provide a valve operating system for an engine.

[0006]

In order to achieve the above object, according to the present invention, one end is interlocked with and connected to a camshaft.
Between the tappets that are connected and contact the engine valve at the other end
A plurality of lockers including a rocker arm provided with a clearance adjustment mechanism.
The arm is located between the engine valve and the camshaft.
Rocker that penetrates the middle of the length of each rocker arm
For valve trains of internal combustion engines that are swingably supported by shafts
In addition, the hydraulic chamber is provided with a piston movable between a position for connecting adjacent rocker arms and a position for releasing the connection according to the hydraulic pressure of the hydraulic chamber. The connection switching mechanism, which is connected to the hydraulic pressure supply passage in the rocker shaft through the oil passage formed in the rocker arm, is different from the rocker shaft of each rocker arm.
It is arranged in a portion deviated to the camshaft side .

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional side view of the embodiment of the present invention and is a sectional view taken along line 1-1 of FIG. 2 of 1
FIG. 3 is an enlarged sectional view of a contact portion between the rocker arm and the engine valve, taken along the line.

First, referring to FIGS. 1 and 2, the engine body E is shown.
Pair of intake valves V1, V2 as engine valves arranged in the
Is a cam C that is integrally provided on a cam shaft CS that is driven at a rotation ratio of 1/2 in synchronization with the rotation of the engine, and first and second swingable around an axis parallel to the cam shaft CS. Due to the operation of the rocker arms 3 and 4 and the connection switching mechanism 5 provided on both rocker arms 3 and 4, both intake valves V
Opening and closing are performed by switching between a state in which 1 and V2 are opened and closed and a state in which only one intake valve V1 is opened and closed. The engine body E is also provided with a pair of exhaust valves (not shown), and these exhaust valves are also opened / closed in the same manner as the intake valves V1 and V2 described above.

The camshaft CS is rotatably arranged above the engine body 1, and the cam C is integrally provided on the camshaft CS at a position corresponding to one intake valve V1. A concentric ridge 6 is integrally provided on the camshaft CS at a position corresponding to the other intake valve V2, and the radius of this ridge 6 is the base circle 7 of the cam C.
Is set to be the same as the radius of. Furthermore, the first rocker arm 3
A cam slipper 8 slidably contacting the cam C is integrally provided at the lower end of one end thereof, and a slipper 9 capable of slidably contacting the raised portion 6 is integrally provided at the lower end of the second rocker arm 4. Therefore, one end of both rocker arms 3 and 4 has a camshaft C.
It will be linked and linked to S.

A rocker shaft 10 having an axis parallel to the camshaft CS is fixed to the engine main body E, and the rocker shafts 10 are capable of swinging in the lengthwise intermediate portions of both rocker arms 3 and 4 adjacent to each other. Is pivoted through .

Hydraulic tappets T1 and T2 as tappet gap adjusting mechanisms are provided at the other ends of the rocker arms 3 and 4, respectively. The hydraulic tappets T1 and T2 have basically the same structure, and the structure of only one hydraulic tappet T2 will be described in detail below.

In FIG. 3, a hydraulic tappet T2 is provided with a hydraulic chamber 15 facing the back of a plunger 14 which is biased by a spring 13 in a direction in which it contacts the intake valve V2, and an oil constantly communicating with an oil supply source (not shown). A check valve 17 is provided between the reservoir chamber 16 and the hydraulic chamber 15.

The other end of the second rocker arm 4 is provided with a bottomed hole 18 which is open to the intake valve V2 side, and the bottomed hole 18 has a spherical head portion 19 at its closed end. The bottomed cylindrical plunger 14 is slid with its spherical head portion 19 on the intake valve V2 side. A ring 20 is fitted on the inner surface of the open end of the bottomed hole 18, and the plunger 20 is prevented from falling out of the bottomed hole 18.

A cylindrical member 21 defining an oil reservoir 16 is slidably fitted in the plunger 14, and the plunger 1 is provided between one end of the cylindrical member 21 and the plunger 14.
The hydraulic chamber 15 facing the back portion of No. 4 is defined. A valve cage 22 pressed by a spring 13 against a cylindrical member 21 is accommodated in the hydraulic chamber 15, and a spherical check valve 17 is accommodated in the valve cage 22 in a floating manner. Further, one end of the cylindrical member 21 has a valve hole 2 communicating with the oil reservoir chamber 16.
3 is bored so that the check valve 17 blocks the communication with the hydraulic chamber 15.

An annular groove 24 communicating with the oil reservoir 16 is provided on the outer surface of the cylindrical member 21, and the annular groove 24 is provided on the outer surface of the plunger 14 regardless of the relative movement of the cylindrical member 21 and the plunger 14. An annular groove 25 that communicates is provided. The other end of the cylindrical member 21 is urged by the spring force of the spring 13 to come into contact with the closed end of the bottomed hole 18, and the other end of the cylindrical member 21 communicates with the oil reservoir chamber 16. A through hole 26 is formed. Further, the bottomed hole 18, the plunger 14 and the cylindrical member 21 define an annular chamber 27, and the second rocker arm 4 is prevented from obstructing the movement of the plunger 14 due to pressurization and depressurization in the annular chamber 27. Therefore, an opening hole 28 is formed to open the inside of the annular chamber 27 to the outside.

A partition wall 36 extending in the axial direction is press-fitted, fixed or integrally molded in the rocker shaft 10. As a result, a first hydraulic pressure supply passage 37 and a second hydraulic pressure supply passage 38 are provided in the rocker shaft 10 with the partition wall 36 interposed therebetween. The first hydraulic pressure supply path 37 and the second hydraulic pressure supply path 38 are individually connected to corresponding hydraulic pressure supply sources (not shown), and a relatively low hydraulic pressure is applied to the first hydraulic pressure supply path 37. The second hydraulic pressure supply passage 38 is supplied with a relatively high hydraulic pressure.

The second rocker arm 4 is provided with an annular groove 39 surrounding the rocker shaft 10, and the rocker shaft 10 is provided with a communication hole 40 for communicating the first hydraulic pressure supply passage 37 with the annular groove 39. To be done. Further, the second rocker arm 4 is provided with an oil passage 31 that connects the annular groove 39 and the annular groove 25 of the plunger 14 in the hydraulic tappet T2, and a throttle 32 is provided in the middle of the oil passage 31. That is, the oil reservoir chamber 16 of the hydraulic tappet T2 is always in communication with the first hydraulic pressure supply passage 37, and the throttle 32 has the first hydraulic pressure supply passage 37.
It has a function of limiting the oil supply speed from the hydraulic pressure supply passage 37.
Further, a diaphragm 33 communicating with the through hole 26 is formed in the upper part of the other end of the second rocker arm 4.
3 has a function of limiting the speed of oil discharged from the oil reservoir 16.
Due to the functions of these throttles 32 and 33, it is possible to avoid a sudden change in the hydraulic pressure in the oil reservoir chamber 16.

The first rocker arm 3 is provided with an annular groove 41 communicating with the first hydraulic pressure supply passage 37, and an oil passage 42 connecting the hydraulic tappet T1 and the annular groove 41. A throttle (not shown) similar to the throttle 32 is provided in the middle of the oil passage 42.

On the other hand, flanges 34 and 35 are provided above the intake valves V1 and V2. Valve springs S1 and S2 surrounding the intake valves V1 and V2 are interposed between the flanges 34 and 35 and the engine body E, and the intake valves V1 and V2 are connected by the valve springs S1 and S2. The valve is biased in the valve closing direction, that is, upward.

The first and second rocker arms 3 and 4 are in sliding contact with each other and can be switched between a state in which their relative angular displacements are possible and a state in which both rocker arms 3 and 4 are integrally connected. A simple connection switching mechanism 5 is provided for each rocker arm 3,
4 corresponding to between the rocker shaft 10 and the camshaft CS , in other words, the rocker arms 3 and 4
A portion that is displaced from the camshaft 10 to the camshaft CS side
It is provided in minutes .

The connection switching mechanism 5 includes both rocker arms 3 and 4.
Between the position where the rocker shaft 10 is connected and the position where the connected state is released, a piston 51 that is movable along an axis parallel to the rocker shaft 10, a stopper 52 that restricts the movement of the piston 51, and a piston 51. And a spring 53 for urging the stopper 52 to move it to the connection release position side.

The first rocker arm 3 is provided with a first guide hole 54 which is open toward the second rocker arm 4 side and is parallel to the rocker shaft 10. The bottom of the first guide hole 54 has a step. A small diameter portion 56 is provided via the portion 55. The piston 51 is slidably fitted in the first guide hole 54, whereby a hydraulic chamber 57 is defined between the piston 51 and the bottom surface of the first guide hole 54. Further, a second oil passage 58 communicating with the hydraulic chamber 57 is bored in the first rocker arm 3, and the second oil passage 58 is provided with a through hole 59 bored in the side wall of the rocker shaft 10. It always communicates with the second hydraulic pressure supply passage 38 therein.

The axial length of the piston 51 is such that when one end of the piston 51 comes into contact with the step portion 55, the other end thereof is the first rocker arm.
It is set so as not to project from the side surface of the frame 3 facing the second rocker arm 4 side.

The second rocker arm 4 has a first rocker arm 4.
Corresponding to the first guide hole 54 of the frame 3
A second guide hole 60 having the same diameter as that of the first rocker arm 3 is opened toward the first rocker arm 3 side, and a disc-shaped stopper 52 is slidably fitted into the second guide hole 60. A small diameter portion 62 is provided on the bottom side of the second guide hole 60 via a regulation step 61.
Further, the second rocker arm 4 is formed with an insertion hole 63 which is concentric with the second guide hole 60 and has a small diameter extending between the bottom portion of the second guide hole 60 and the outer side surface thereof.
A small-diameter guide rod 64, which is integrally and concentrically provided with, is inserted into the insertion hole 63. Further, a coil-shaped spring 53 that surrounds the guide rod 64 is interposed between the stopper 52 and the bottom surface of the second guide hole 60.

In the connection switching mechanism 5 as described above, the first
The second guide holes 54 and 60 are used for the first rocker arm 3
When the cam slipper 8 is in sliding contact with the base circle portion 7 of the cam C, and the slipper 9 in the second rocker arm 4 is in sliding contact with the raised portion 6, the cam slipper 8 is concentric.

Next, the operation of this embodiment will be described. When the engine is operating at a low speed, the hydraulic chamber 5 of the connection switching mechanism 5 will be described.
No hydraulic oil is supplied to 7. As a result, the stopper 5
2 is pushed to the first rocker arm 3 side by the spring 53,
The piston 51 contacts the step portion 55. In this state, the contact surfaces of the piston 51 and the stopper 52 are located at positions corresponding to the sliding contact surfaces of the first and second rocker arms 3 and 4.
Therefore, the first and second rocker arms 3 and 4 are in sliding contact with each other, and the piston 51 and the stopper 52 are
Are in slidable contact with each other so that relative angular displacement is possible.

In the connection release state of the connection switching mechanism 5,
The first rocker arm 3 is oscillated by the cam C by the rotating operation of the cam shaft CS, and one intake valve V1 is opened and closed at a timing and a lift amount according to the shape of the cam C. On the other hand, the second rocker arm 4 has its slippers 9
Is in sliding contact with the raised portion 6, and the other intake valve V2 remains closed.

During high speed operation of the engine, a relatively high pressure hydraulic oil is supplied to the hydraulic chamber 57 of the connection switching mechanism 5. This causes the piston 51 to contract the spring 53 until the stopper 52 comes into contact with the regulation step portion 61, and then the second guide hole 60.
It moves inward and the piston 51 connects the first and second rocker arms 3 and 4.

As described above, in the state where the first and second rocker arms 3 and 4 are integrally connected, both the first and second rocker arms 3 and 4 swing in response to the rotation of the cam C and both intake air Both valves V1 and V2 are opened and closed.

When both the intake valves V1 and V2 are closed when the connection switching mechanism 5 is connected, the hydraulic tappets T1 and T2 work so that the first rocker arm 3 has the cam slipper 8 and the cam C has the cam C. Of the second rocker arm 4 and the slipper 9 of the second rocker arm 4 are urged in the direction of sliding contact with the raised portion 6. Therefore, since the axes of the first and second guide holes 54 and 60 are aligned with each other, the piston 51 is smoothly moved, and the connection switching mechanism 5 is reliably connected.

In this way, by changing the opening / closing operation mode of both intake valves V1 and V2 in accordance with the operating state of the engine, it is possible to reduce fuel consumption and improve engine output, and furthermore, each hydraulic tappet. Since relatively low hydraulic pressure is supplied to T1 and T2, and relatively high hydraulic pressure is supplied to the connection switching mechanism 5, the hydraulic tappets T1 and T2 and the connection switching mechanism 5 must be operated at appropriate hydraulic pressures. become.

Further, it is inevitable that both rocker arms 3 and 4 become large and heavy in the portion corresponding to the connection switching mechanism 5, and further that both rocker arms 3 and 4 become large in the portion where the hydraulic tappets T1 and T2 are provided. Although an increase in weight is inevitable, the connection switching mechanism 5 and the hydraulic tappets T1 and T2 are arranged on the rocker arms 3 and 4 on both sides of the rocker shaft 10. By doing so, the connection switching mechanism 5 and the two hydraulic tappets T1, T2 are provided on one side of the rocker shaft 10.
Compared with the one provided on both rocker arms 3 and 4, the balance around both rocker arms 3 and 4 around the rocker shaft 10 is improved, whereby the valve jump rotation limit can be improved, and as a result, the high rotation speed of the engine can be improved. It is possible to cope with higher output.

Moreover, the connection switching mechanism 5 is provided with a rocker shaft.
By displacing the camshaft CS side from 10
The rocker arms 3 and 4 are connected to each other in a switching state (that is,
In the coupling operation state of the coupling switching mechanism 5), the camshaft CS
Transmitted from one end of the first rocker arm 3
Of the intake valves V1 and V2 are
Multiple rocker arms 3, 4 at a part relatively close to the CS
Since it can be distributed and transmitted to the other end side of the
The distributed transmission position (that is, the position of the connection switching mechanism 5) and the first lock
The distance from one end of the arm 3 is made as short as possible and the first rocker
The load on one end of the arm 3 can be reduced, and
The rocker arm 3 is reduced in weight and the inertial mass is reduced.
Can be reduced.

[0034] Moreover The hydraulic tappets T1, T2 and connection selection mechanism 5 from the first and second hydraulic pressure supply passage 37 is provided to be supplied with oil the rocker shaft 10 are disposed on either side of the rocker shaft 10 By doing so, 31, 42, 58 can be simplified to facilitate oil passage formation.

The present invention is not limited to the above-described embodiment in which a pair of rocker arms are individually associated with engine valves,
As in the valve gear device proposed by the present applicant in Japanese Patent Application No. 61-200955, rocker arms connected to and linked to the engine valve are arranged on both sides of the rocker arm that can be free to the engine valve, The present invention is also applicable to a valve operating device that switches connection and disconnection of adjacent rocker arms.

[0036]

As described above, according to the present invention, a plurality of filters are provided.
The rocker arm penetrates the middle part in the length direction of the rocker arm.
A center pin that is swingably supported on the rocker shaft
In a bot type valve train, adjacent rockers
Between the position to connect the arm and the position to release the connection
Connection switching with built-in hydraulically responsive piston
The mechanism is camcordered from the rocker shaft of each rocker arm.
Since it is arranged in the portion deviated to the chaft side, the tappet gap adjusting mechanism which is an inertial mass and the connection switching mechanism are dispersedly arranged on both sides in the length direction of the rocker shaft to improve the mass balance of the rocker arm around the rocker shaft . Can
Can, thereby increasing the valve jump misfire limit, the high rotation of the engine may correspond to a high output.

Moreover, the connection switching mechanism is biased to the camshaft side.
By positioning it, the adjacent rocker arms were connected.
In the switching state, one camshaft and one rocker arm
Valve opening drive for multiple engine valves centrally transmitted to the end
Force is applied to multiple rocker arms relatively close to the camshaft.
Is it possible to disperse and transmit to the other end of the system?
From the distribution transmission position (that is, the position of the connection switching mechanism)
Keep the distance from one end of one rocker arm as short as possible
The load on the two rocker arms can be reduced,
As a result, the rocker arm is lightened and its inertial mass is reduced.
It can be further reduced.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view of an embodiment and is a cross-sectional view taken along line 1-1 of FIG.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is an enlarged cross-sectional view of a contact portion between a rocker arm and an engine valve.

[Explanation of symbols]

3, 4 rocker arm 5 connection switching mechanism 10 rocker shaft 38 hydraulic supply path 51 piston 57 hydraulic chamber 58 oil path CS camshaft T1, T2 hydraulic tappet as tappet gap adjusting mechanism V1, V2 intake valve as engine valve

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area F02D 11/06 Z

Claims (1)

[Claims] 1. A rocker arm (3, 4) provided with a tappet clearance adjusting mechanism (T1, T2), one end of which is linked and connected to a camshaft (CS), and the other end of which is in contact with an engine valve (V1, V2). ) Including a plurality of rocker arms (3, 4) are arranged between the engine valves (V1, V2) and the camshaft (CS), and each rocker arm (3, 4) is provided .
4) A rocker shaft (1
In the valve operating system of the internal combustion engine, which is rockably supported by the control unit (0), the position where the adjacent rocker arms (3, 4) are connected according to the hydraulic pressure of the hydraulic chamber (57) and the connection thereof are The hydraulic chamber (57) is provided with a piston (51) that is movable between the hydraulic chamber (57) and a release position, and an oil passage (58) is provided in a rocker arm (3) provided with the hydraulic chamber (57). The connection switching mechanism (5), which is connected to the hydraulic pressure supply passage (38) in the rocker shaft (10), includes the rocker arms.
Camshuff from rocker shaft (10) of (3, 4)
A valve operating device for an internal combustion engine, wherein the valve operating device is arranged in a portion that is deviated to the CS side .