JPH052807B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a valve operating mechanism for an engine having a plurality of intake valves and/or exhaust valves for each cylinder. The present invention relates to a valve operating mechanism for an engine that has a function of controlling the valve and correcting the gap between the valve and the valve driving mechanism, that is, the so-called valve lash.

[Conventional technology]

Conventionally, in engines equipped with a plurality of intake valves and/or exhaust valves for each cylinder, some of the intake valves, some of the exhaust valves,
Alternatively, a system has been proposed in which a portion of each of the intake and exhaust gases is stopped in a specific engine rotational speed range, mainly in a low-medium rotational speed range, thereby improving the engine output and fuel efficiency as a whole.

In addition, we have installed a so-called hydraulic lash adjuster in order to keep the gap between the intake and exhaust valves and the valve drive mechanism, or so-called valve lash, always at zero, eliminating maintenance-free valve lash readjustment and reducing valve noise. known to be used.

[Problem to be solved by the invention]

By the way, in the past, these technologies were developed separately, but in engines, high output,
Fuel efficiency and maintenance-free products are increasingly required. For this reason, the present applicant previously proposed a combination of the above-mentioned two (Patent Application No. 57-
No. 125381 (Japanese Unexamined Patent Publication No. 59-15615)).

In this type, the fulcrum of the rocker arm, which opens and closes the intake valve or exhaust valve by following a cam that synchronizes with the rotational speed of the engine, is moved by the static pressure reaction of the oil of the hydraulic latch adjuster installed in the cylinder head. A valve stop mechanism is provided, which is supported by a plunger that receives the rocker arm, and which makes the plunger movable by releasing the static pressure of the oil and eliminating the support reaction force against the rocker arm.

By the way, when a lash adjuster is applied to a valve that is at rest, the fulcrum position rises during the time of rest, and the phases of the engagement positions such as the shift pin holes do not match when the valve returns to operation. In order to achieve this, a more complicated mechanism is required.

Non-dead valves, on the other hand, require conventional hydraulic lash adjusters. For this reason, for example, if one cylinder with four valves is provided with a stop function, there will be a total of four hydraulic lash adjusters, and one or two of those hydraulic lash adjusters also have a stop mechanism. However, it has a complicated structure and is less reliable.

In addition, in the above configuration, the hydraulic lash adjuster equipped with a stop mechanism is large in size due to its structure, and even if one of the hydraulic lash adjusters is a small one, the distance between the shafts of adjacent valves is wide. Therefore, the engine as a whole becomes larger, which is disadvantageous in terms of weight, etc. Moreover, if the number of cylinders is increased, this tendency will become even more serious, and there will be problems such as aggravating the inconvenience.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide an engine valve mechanism that is simple in structure, compact, and capable of high output, fuel efficiency, and maintenance-free operation.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention provides a first aspect of the present invention in which, in an engine provided with a plurality of intake valves and/or exhaust valves for each cylinder, a first
a rocker arm, a second rocker arm that selectively operates the intake valve or the exhaust valve at a timely manner, a valve operation control means that engages or disengages the first rocker arm and the second rocker arm, and the first rocker arm and the second rocker arm. The present invention is characterized by having a support shaft rotatably provided with an eccentric sleeve having a fixed bearing portion, and a lash adjuster that rotates the eccentric sleeve to eccentrically correct the valve lash to zero. Also,
The second invention includes the first rocker arm of the first invention and the second rocker arm of the first invention.
It is characterized by having a valve brush adjustment means on either side of the rocker arm.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

A cylinder sleeve 2 is press-fitted into a cylinder barrel 1 of an engine, and a piston 3 is configured to reciprocate within this cylinder sleeve 2.
A cylinder head 4 is attached to the upper part of the cylinder barrel 1, and the piston 3 and cylinder sleeve 2 form a combustion chamber 5. A pair of intake passages 6 and an exhaust passage 7 are formed in the cylinder head 4, and these communicate with the combustion chamber 5 through an intake port 8 and an exhaust port 9. A total of four valves 10 are provided, one pair each on the intake side and the exhaust side, which open and close.

In the conventional manner, each valve 10 is
A valve spring 11 is inserted between the cylinder head 4 and the cylinder head 4.
is compressed, thereby urging the valve 10 to always close the intake port 8 and the exhaust port 9. Above the valve 10 are a first rocker arm 12 and a second rocker arm 1, as shown in FIG.
3 are suspended horizontally, and these two rocker arms 12, 13
is rotatably supported by a swing shaft 14. The swing shaft 14 includes a support shaft 16 having an oil passage 15 and an eccentric sleeve 17 rotatably provided thereon. This eccentric sleeve 17 is eccentrically set so that the valve side 17a is thin and the hydraulic lash adjuster side 17b is thick.
The bearings of the first and second rocker arms 12 and 13 are fixed, and the eccentric sleeve arm 18
The end portion 18a thereof is in contact with the plunger pivot 20a at the upper end of the plunger 20 of the hydraulic lash adjuster 19.

The first rocker arm 12 and the second rocker arm 13 are provided with valve operation control means. That is, the cylinder 21 is attached to the first rocker arm 12, and the cylinder 21 is attached to the second rocker arm 13.
2 are formed coaxially with the rocking shaft 14 with openings on opposite sides, and the first
An oil passage 23 for supplying hydraulic oil to the cylinder 21 is formed in the rocker arm 12, and this oil passage 23 communicates with the oil passage 15 of the support shaft 16 through an opening 24 formed in the eccentric sleeve 17 and the support shaft 16. . Cylinder 21 of first rocker arm 12
A locking piston 25 is movably inserted into the cylinder 22 of the second locker arm 13, and a guide pin 26 is loosely inserted into the cylinder 22 of the second locker arm 13, with its tip 26a protruding outward and a clip 27 being engaged with it. and is locked to the second rocker arm 13 so as to be movable in the axial direction. A spring 28 is installed in the cylinder 22 of the second rocker arm 13.
The guide pin 26 and the locking piston 25 are compressed between the wall of the guide pin 26 and the collar 26b of the guide pin 26.
Push the locking arm 12 direction and locking piston 2
5 is located within the cylinder 21 of the first rocker arm 12. When the locking piston 25 is supplied with hydraulic oil from the oil passage 15 of the support shaft 16 and into the cylinder 21 from the oil passage 23 of the first rocker arm 12, this locking piston 2
5 moves forward and the cylinder 2 of the second rocker arm 13
2, so that the second rocker arm 13 operates in conjunction with the first rocker arm 12. On the other hand, when the supply of hydraulic oil is released, the locking piston 25 is moved back by the biasing force of the spring 28 and positioned within the cylinder 21 of the first rocker arm 12, and the second rocker arm 13 is no longer interlocked.

The working end 12a of the first rocker arm 12 is connected to the second rocker arm 12.
As shown in the figure, the valve stem 10a is in direct contact with the upper part of the valve stem 10a, and the working end 13a of the second rocker arm 13 is provided with a tappet adjuster screw 29, which is a valve brush adjusting means, and its tip 29a is connected to the other end. It is in contact with the upper part of the valve stem 10a. This tappet adjustment screw 29 has a height difference in the abutment position of each valve 10, and the cylinder head 4 and the like also have a height difference, so that adjacent valves 10 have different positions in the height direction. Since the heights are not necessarily the same, they are provided to adjust the valve rush between the corresponding valves 10.

As shown in FIG. 3, this adjustment is performed by moving the locking piston 25 located in the cylinder 21 of the first rocker arm 12 forward by the above-mentioned operation and fitting it into the cylinder 22 of the second rocker arm 13. . By adjusting the strike screw 29 to make the clearance zero, the clearance of both valves 10 can be maintained at zero. Furthermore, during operation, it is thought that the temperature of both adjacent valves 10 rises at almost the same rate, and since the valves 10 are made of the same material, their elongation is constant and the clearance can always be maintained at zero. .

A cam 31 provided on the camshaft 30 operates the first rocker arm 12 as shown in FIG. 2, and the second rocker arm 13 is operated in conjunction with the first rocker arm 12 by the aforementioned locking piston 25. do.

In Fig. 2, hydraulic lash adjuster 1
9 is attached to the cylinder head 4. The structure of the latch adjuster 19 is such that a plunger 20 is slidably provided in a cylindrical body 32 with an open upper end, and a plunger spring 34 is provided in a high pressure chamber 33 below the plunger 20.
is contracted to constantly urge the plunger 20 upward. The plunger 20 has a spherical upper end and a plunger pivot 20 serving as a rotation fulcrum.
a, and also allows hydraulic oil to be supplied to an internal reservoir chamber 35. A check ball 36 is provided on the lower surface of the plunger 20 in a cage 37 corresponding to the lower opening of the plunger 20.
It is held and attached to. The hydraulic oil is supplied to the reservoir chamber 35 through the hydraulic oil reservoir 38 of the body 32.
From there, it passes through the hydraulic oil hole 39 to the operating groove 40 of the plunger 20, and from there, it passes through the communication hole 41 of the plunger 20 and reaches the reservoir chamber 35.

When a clearance is created between the working end 12a of the first rocker arm 12 and the valve stem head, the hydraulic latch adjuster 19 is supplied with hydraulic oil and the plunger 20 is raised. This allows the eccentric sleeve arm 18 of the swing shaft 14 to
is rotated counterclockwise in FIG. 2, thereby rotating the eccentric sleeve 17 counterclockwise. Since this eccentric sleeve 17 is eccentric toward the hydraulic lash adjuster 19 as described above, this rotation lifts the swing shaft 14 side of the first rocker arm 12 and the second rocker arm 13, and on the other hand, this causes the working end to be lifted. 12a and 13a are pushed down and the clearance becomes zero.

Next, the operation of this embodiment will be explained.

Engine intake valve 10 and exhaust valve 1
0, when the second rocker arm 13 is not connected to the first rocker arm 12 as shown in FIG.
The oil is then supplied to the cylinder 21 through the oil passage 23 of the second rocker arm 12. Then the locking piston 25
moves forward and the cylinder 21 of the second rocker arm 13
The second rocker arm 13 is connected to the first rocker arm 12 and is interlocked with the operation of the first rocker arm 12 by the cam 30. As a result, the pair of valves 10 open and close simultaneously.

Next, a description will be given of the transition from the above-mentioned all-valve operating state to a partial valve operating state. When the supply of hydraulic oil is released in response to a signal from the sensor, the locking piston 25 is pushed by the guide pin 26 by the biasing force of the spring 28 and retreats, and the fitted state of the second rocker arm 13 with the cylinder 22 is released. As a result, the second rocker arm 13 no longer operates, and the valve 1, which had been opened and closed by the second rocker arm 13,
0 is not activated.

Further, if a clearance occurs between the working ends 12a, 13a of the first rocker arm 12 or the second rocker arm 13 and the valve stem 10a, the oil pressure in the high pressure chamber 33 will decrease, but the reservoir chamber 35 is adjusted to compensate for the decrease. Then, the check ball 36 is opened, the required amount of hydraulic oil is replenished into the high pressure chamber 33, and the plunger 20 is raised. This results in
The eccentric sleeve arm 18 of the swing shaft 14 is rotated counterclockwise in FIG. 2, causing the eccentric sleeve 17 to rotate counterclockwise. This eccentric sleeve 17 is connected to the lash adjuster 19 as described above.
Since it is eccentric to the side, this rotation lifts the swinging shaft 14 side of the first rocker arms 12, 13, and on the other hand, this pushes down the working end.
The clearance generated between the first rocker arms 12 and 13 is set to zero.

Note that the present invention is not limited to the above-mentioned embodiments. For example, the camshaft may be equipped with a low-speed cam and a high-speed cam, and a valve that is opened and closed by a first rocker arm operated by the low-speed cam may be controlled by a valve control means. It is also possible to apply the present invention to a valve operating mechanism in which the first rocker arm is engaged with a second rocker arm operated by a high-speed cam to control the operation of the valve.

〔Effect of the invention〕

As described above, the present invention includes a valve operation control means that engages or disengages a first rocker arm that opens and closes an intake valve or an exhaust valve and a second rocker arm that selectively operates the intake valve or exhaust valve at appropriate times. An eccentric sleeve, on which the bearings of the first rocker arm and the second rocker arm are fixed, is rotatably provided on the support shaft, and a lash adjuster is provided that rotates the eccentric sleeve to correct the valve lash to zero. To provide a device that eliminates the need to provide a lash adjuster for each valve, eliminates the need for the lash adjuster to have a special structure, allows the lash adjuster to be made smaller, and reduces backlash to zero. The entire structure can be miniaturized, and since the valve operation control means is provided between the two rocker arms, the structure is simple and does not require much space for mounting on the engine. Therefore, the entire engine can be made smaller, and high output, fuel efficiency, and maintenance-free performance can be easily achieved.

Further, by providing a valve lash adjustment means on either the first rocker arm or the second rocker arm, the valve lash with the corresponding valve can be adjusted.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of an engine valve mechanism to which the present invention is applied, FIG. 2 is a partially enlarged cross-sectional view of the same, and FIG. 3 is a cross-sectional view of the main part of the present invention. 12... First rocker arm, 13... Second rocker arm, 14... Rocking shaft, 16... Support shaft, 17... Eccentric sleeve, 18... Eccentric sleeve arm, 19... Hydraulic latch adjuster, 21, 22... Cylinder, 25... Locking piston, 26... Guide pin, 28... Spring.

Claims (1)

[Scope of Claims] In an engine having a plurality of intake valves and/or exhaust valves for each cylinder, a first valve that opens and closes the intake valve or the exhaust valve;
a rocker arm, a second rocker arm that selectively operates the intake valve or the exhaust valve at a timely manner, a valve operation control means that engages or disengages the first rocker arm and the second rocker arm, and the first rocker arm and the second rocker arm. A valve mechanism for an engine, which includes a support shaft rotatably provided with an eccentric sleeve having a fixed bearing part, and a lash adjuster that rotates the eccentric sleeve to eccentrically correct the valve lash to zero. 2. In an engine having a plurality of intake valves and/or exhaust valves for each cylinder, a first valve that opens and closes the intake valve or the exhaust valve.
a rocker arm, a second rocker arm that selectively operates the intake valve or the exhaust valve at a timely manner, a valve operation control means that engages or disengages the first rocker arm and the second rocker arm, and the first rocker arm and the second rocker arm. a support shaft rotatably provided with an eccentric sleeve having a fixed bearing portion; a lash adjuster that rotates the eccentric sleeve to correct the valve lash to zero; A valve mechanism for an engine having a valve lash adjustment means provided on either side.