JPH0568604B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a valve driving device equipped with a valve stop mechanism that stops part of an intake or exhaust valve of an engine depending on the operating state of the engine.

(Prior art) Conventionally, in multi-cylinder engines, during low-load operation, the intake valves of some cylinders are stopped, the filling efficiency of the remaining cylinders is increased, and pumping loss is reduced by so-called cylinder number control. It is.

In addition, in engines with two intake valves per cylinder, during low-load operation, one intake valve is stopped and the intake flow rate from the other intake valve is increased to increase the swirl in the combustion chamber. Controls are in place to increase combustibility.

By the way, there are basically two methods for stopping valves in the above-mentioned control: mechanical (see Japanese Patent Laid-Open No. 52-56212) and hydraulic
-Refer to Publication No. 51907) has been proposed.

The former is a locking arm type valve stop mechanism that prevents the power of the push rod from being transmitted to the intake valve via the locking arm by rotating or sliding the locking plate with an actuator (diaphragm type, hydraulic type, etc.). However, since it is necessary to position the locking plate and actuator relative to the cylinder head, etc., it cannot be used in a direct type valve drive device that directly operates the valve with a cam.

Furthermore, since it is necessary to provide a locking plate and an actuator, the mechanism becomes bulky and it is difficult to make it compact.

The latter is a locking arm type valve stop mechanism that prevents the power of the cam from being transmitted to the intake valve via the locking arm by hydraulically moving the plunger supported by the locking arm. If you adopt the method of releasing air and then adding air, there is a risk that the timing of the valve operation will be incorrect due to the difference in compression ratio if the air is not completely removed when the valve is operated. Unless a large hydraulic pump is used, it is difficult to increase the rotation limit because it has poor followability when moving in and out.

Further, since it is necessary to provide a plunger or the like to the rocker arm, the mechanism becomes large-scale and it is difficult to make it compact.

(Object of the Invention) The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide an engine valve drive device that makes it possible to make the valve stop mechanism more compact and to increase the rotation limit. This is the purpose.

(Structure of the Invention) Therefore, the present invention provides a valve drive device which is provided between a valve drive cam and an intake or exhaust valve and which transmits the movement of the valve drive cam to the valve, and which includes a body that slides within a guide member. a slider that slides within the body in the same direction as the sliding direction of the body; and a slider that is supported so as to be freely protrusive and retractable in a direction perpendicular to the sliding direction of the slider and the body, and engages and disengages the body and the slider. a selector pin, an oil passage communicating with the pressure receiving surface of the selector pin is opened on the outer peripheral surface of the body, and an oil supply port communicating with the oil passage of the body is provided on the sliding surface of the body of the guide member. The oil supply passage, which is open and communicates with the oil supply hole, is equipped with an oil supply control device that controls the supply of oil according to the operating state of the engine and controls the activation/deactivation of the valve. It is.

Therefore, when the valve is activated, the oil supply control device supplies or stops oil (hydraulic) supply.
The selector pin is protruded to engage the body and slider, and the movement of the valve drive cam is transmitted to the valve via the body and slider. When the valve is not operating (stopped), oil (hydraulic pressure) is supplied by the oil supply control device. The selector pin is retracted to separate the body and slider, and the movement of the valve drive cam is no longer transmitted to the valve.

(Effects of the Invention) According to the present invention, a body and a slider are provided between the valve drive cam and the valve, and the engagement and disengagement of the body and the slider is performed by a selector pin that is controlled to protrude and retract using hydraulic pressure. Because it is a thing,
It is more compact than the conventional mechanical type,
It can also be used in direct type valve drive devices.

Additionally, compared to conventional hydraulic systems, the system is more reliable in operation and has a higher rotational limit.

(Embodiment) As shown in FIGS. 1 and 2, a cylinder head 2 is attached to the upper part of the engine body 1, and two intake ports 4a communicating with the combustion chamber 3 are provided at the bottom of the cylinder head 2. 4a and exhaust port 5a,
The intake ports 4a, 4a are communicated with two independent intake passages 6a, 6a, respectively, and the exhaust ports 5a, 5a are communicated with one exhaust passage 7. Each intake passage 6a,
A fuel injection valve 8 is provided at 6a.

Inside the cylinder head 2, there is an intake port 4.
Intake valves 9a, 9a that open and close a, 4a, and exhaust valve 10 that opens and closes exhaust ports 5a, 5a.
a, 10a are provided, each valve 9a, 9a, 1
0a, 10a are valve train cams 12,..., 1 disposed inside the head cover 11 above the cylinder head 2.
2, the valves are opened and closed via valve stop mechanisms 13, . . . , 13.

FIG. 3 shows each valve 9a, 9a, 10a, 10
This is an enlarged sectional view representatively showing one intake valve 9a, the valve stop mechanism 13, and the valve drive cam 12 in FIG. It represents.

In the figure, the valve train cam 12 and the intake valve 9a
The cylinder head (guide member) 2 between the
A body fitting hole 2a is formed, and the body fitting hole 2a is formed.
A cylindrical body 15 whose top portion 15a is closed is fitted into the body 15 so as to be vertically slidable.

A recess 1 formed in the top 15a of the body 15
A shim 16 that comes into contact with the valve operating cam 12 is fitted into the shim 5b.

An axial slider fitting hole 15c is formed in the body 15, and the slider fitting hole 15c
A slider 17 is fitted in the slider 17 so as to be vertically slidable in the same direction as the sliding direction of the body 15.

In the slider 17, selector pin fitting holes 17a, 17a are formed in a direction perpendicular to the axial direction, for example, at two equal positions on the circumference, and in the outer peripheral part 15d of the body 15, a valve actuation hole is formed. At times, selector pin fitting holes 15e, 15e are formed to match the selector pin fitting holes 17a, 17a, and the selector pin 1 is formed in the selector pin fitting holes 17a, 17a of the slider 17.
8 and 18 are fitted (supported) in the selector pin fitting holes 15e and 15e of the body 15 in a direction perpendicular to the sliding direction of the slider 17 and the body 15 so as to be able to protrude and retract.

The selector pin 18 is biased in the projecting direction by a return spring 19, and when the valve is operated, the biasing force of the return spring 19 pushes the selector pin 18 toward the body 1.
5 into the selector pin fitting hole 15e until it is stopped by the stopper ring 20, and the slider 17 and the body 15 are engaged so as to interlock in the sliding direction (the state shown in the left half of Fig. 3). On the other hand, when the valve is stopped (inoperative), it is pulled out from the selector pin fitting hole 15e of the body 15 by hydraulic pressure, which will be described later, and the slider 17 is separated from the body 15 so that it does not interlock with the body 15 (the state shown in the right half of Fig. 3). ).

Inside the body 15 is a follower spring 21 that urges the body 15 and the slider 17 in the direction of separation.
has been reduced.

The intake valve 9a has a valve stem 9b supported by a stem guide 22 fitted to the cylinder head 2 so as to be vertically slidable, and a spring seat 23 attached to the upper part of the valve stem 9b and a spring seat of the cylinder head 2. The top portion 9d of the valve stem 9b comes into contact with the bottom portion of the slider 17 while being biased upward by valve springs 25 and 26 compressed between the valve stem 9b and the valve stem 24.

On the other hand, the selector pin fitting hole 15e formed in the outer peripheral portion 15d of the body 15 functions as an oil passage communicating with the pressure receiving surface at the tip end of the selector pin 18.

The body fitting hole 2a of the cylinder head (guide member) 2 is formed with an annular oil supply groove 2b that constantly communicates with the selector pin fitting hole 15e of the body 15. An oil supply control device 28 is connected to the oil supply passage 27 of the head 2 .

The oil supply control device 28 includes a switching valve 30 that detects the engine rotation speed and engine load and is controlled to open and close by a control signal output from a control circuit 29 when the load is low or the engine rotation is low.
Accordingly, the hydraulic pressure pumped from the oil tank 31 via the hydraulic pump 32 is supplied to the oil supply passage 27, or the hydraulic pressure in the oil supply passage 27 is returned to the oil tank 31 via the return passage 33.

If the engine valve drive device is configured as described above, when the valve is operated (the state shown in the left half of Fig. 3), the switching valve 30 is in the closed state, and the hydraulic pump 3 is in the closed state.
The hydraulic pressure sent from the oil supply passage 2 is returned to the oil tank 31 via the return passage 33, and
No hydraulic pressure is applied to 7.

Since hydraulic pressure is not acting on the oil supply groove 2b and the selector pin fitting hole (oil passage) 15e of the body 15, the return spring 19
The selector pin 18 is moved to the body 15 by the biasing force of
The slider 17 is fitted into the selector pin fitting hole 15e of the slider 17, and the slider 17 and the body 15 are engaged with each other.

Therefore, as the cam 12 rotates, the integrated body 15 and slider 17 slide up and down, and the intake valve 9a is opened via the body 15 and slider 17.
will be opened and closed.

On the other hand, when the valve is stopped (inoperative) (the state shown in the right half of Figure 3), the control circuit 29
The switching valve 30 is opened by a control signal output from the hydraulic pump 32, and the hydraulic pressure sent from the hydraulic pump 32 acts on the oil supply passage 27.

Then, the oil pressure acts on the oil supply groove 2b and the selector pin fitting hole (oil passage) 15e of the body 15, and the selector pin 18 is pulled out from the selector pin fitting hole 15e of the body 15, and the slider 17 and the body are removed. 15 will be separated.

Therefore, as the cam 12 rotates, the body 15 slides up and down in the body fitting hole 2a, but the slider 17 comes into contact with the top 9d of the valve stem 9b of the intake valve 9a in the upward movement (valve closing) position. Since the intake valve 9a does not slide vertically in this state, the operation of the intake valve 9a stops.

When the selector pin 18 is supported on the slider 17 as in this embodiment, the weight of the body 15 is reduced, making it possible to further increase the rotation limit.

In the above embodiment, when the valve is stopped (inoperative), the selector pin 18 is hydraulically removed from the selector pin fitting hole 15e of the body 15 to separate the slider 17 and the body 15. As shown in the figure, selector pin 18
is urged in the retracting direction by the return spring 19, and when the valve is operated, the outer peripheral portion 15 of the body 15
Hydraulic pressure is supplied between the selector pins 18 and 18 from the oil supply hole 15i provided at While engaging the body 15 so as to move in the sliding direction, when the valve is stopped (inoperative), the selector pin 18 is pulled out from the selector pin fitting hole 15e of the body 15 by the biasing force of the return spring 19. , the slider 17 may be detached from the body 15 so as not to be interlocked with the body 15.

With this configuration, the valve can be reliably stopped when the oil pressure is low, such as during idling, and there is no need to use a large-capacity hydraulic pump or the like.

In the above embodiment, two intake valves 9 are provided for one cylinder.
Although we have taken as an example the control of one intake valve 9a in an engine in which one intake valve 9a is provided, one exhaust valve 10a may be controlled at the same time. It can also be applied to so-called cylinder number control in a cylinder engine.

Further, in the above embodiment, a direct type in which the intake valve 9a is directly actuated by the cam 12 is taken as an example, but it can also be applied to a rocker arm type in which a rocker arm is interposed.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an engine equipped with a valve drive device according to the present invention, Fig. 2 is a plan view schematically showing the arrangement structure of the intake passage and exhaust passage with respect to the combustion chamber, and Fig. 3 is the left half. FIG. 4 is a vertical sectional view of the valve driving device according to a modification of FIG. 3. FIG. 2...Cylinder head (guide member), 2a...Body fitting hole (body sliding surface), 2b...Oil supply groove (oil supply port), 9a...Intake valve, 10a
...Exhaust valve, 12...Valve drive cam, 13...Valve stop mechanism, 15...Body, 15e...Selector pin fitting hole (oil passage), 17...Slider, 18
...Selector pin, 27...Oil supply passage, 28
...Oil supply control device.

Claims (1)

[Scope of Claims] 1. A valve drive device that is provided between a valve drive cam and an intake or exhaust valve and that transmits the movement of the valve drive cam to the valve, comprising: a body that slides within a guide member; and a body that slides within a guide member; A slider that slides inside in the same direction as the sliding direction of the body, and a selector pin that is supported so as to be freely protrusive and retractable in a direction perpendicular to the sliding direction of the slider and the body, and that engages and disengages the body and the slider. An oil passage communicating with the pressure receiving surface of the selector pin is opened in the outer peripheral surface of the body, and an oil supply port communicating with the oil passage of the body is opened in the sliding surface of the body of the guide member, An oil supply passage communicating with the oil supply hole is provided with an oil supply control device that controls the supply of oil according to the operating state of the engine and controls activation/deactivation of a valve. Valve drive device.