JPH0124323Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is used for cylinders in multi-cylinder internal combustion engines with a variable number of cylinders that can be deactivated. Regarding improvements.

When an internal combustion engine is idling or operating under low load, less fuel is supplied to the combustion chamber, so the combustion chamber cannot be kept at an appropriate heating state, reducing combustion efficiency and fuel consumption. .

Therefore, conventional engines with variable number of cylinders reduce the number of cylinders that supply fuel during the above-mentioned operation and increase fuel to the operating cylinders to improve combustion efficiency and reduce fuel consumption. known from. In such an internal combustion engine, if the intake and exhaust valves of the cylinder to which fuel supply is stopped are also stopped,
The pumping loss is reduced, the engine load is lightened, and fuel consumption is more effectively reduced.

Incidentally, the following has been devised as a valve operating mechanism for an internal combustion engine that stops the operation of intake and exhaust valves.

As shown in FIG. 1A, this mechanism has a rocker arm 3 with a rocker shaft 4 as its rotation axis, and an axis b that is vertically downwardly spaced a distance e from the shaft center a of the rocker shaft 4 (eccentric). attached to the rocker shaft 4 so as to be rotatable with respect to each other via an inner bush 1 and an outer bush 2 having an axis c vertically downward and spaced apart (eccentric) by a distance e with respect to the axis b of the inner bush 1; The eccentric inner and outer bushes 1, 2 of the rocker arm 3 are rotatably controlled by a link device 10 and a piston device 20, as shown in FIG. 1B.

This link mechanism 10 includes an inner transmission member 11 that is integrally connected to an inner bush 1 as shown in FIG.
The outer transmission member 12 is connected by a long groove 14 to the inner and outer transmission members 11 and 12, and the inner and outer transmission members 11 and 12 are connected to a connecting pin 15 provided at a location equidistant from the axis a of the rocker shaft 4, and these are connected to the axis a. It is composed of links 16 and 17 of equal length that are pulled upward while being rotated relative to a. The other ends of the links 16 and 17 are connected by a pin 18 at the same fulcrum, and the piston device 2
It is connected to rod 21 of 0.

This piston device 20 guides high pressure air from an air introduction pipe 22 to a pipe 24 or a pipe 25 via a switching valve such as a pilot type solenoid valve 23.
When air is introduced into the tube 25, the outlet 26 communicates with the atmosphere and the rod 21 is pushed down, and when air is introduced into the tube 25, the outlet 27 communicates with the atmosphere and the rod 21 is pulled up. ing.

Then, in the state shown in FIG. 1B where the piston device 20 is pushing down the rod 21, a downward force acts on the link device 10 connected to the piston device 20, and the inner and outer bushes 1 and 2 are pushed down as shown in FIG. 1A. In the position, the camshaft 5
The valve operating motion of the cam 6 attached to the shaft is transmitted from the rocker arm 3 to the intake and exhaust valves 9 via the tappet 7 and push rod 8. In the non-operating state where the piston device 10 is pulling up the rod 21, the link device 10 rotates the inner and outer bushes 1 and 2 in the directions of arrows P and Q in FIG. 1A, and the rocker arm 3 moves as shown in FIG. 1C. When the push rod 8 is pulled upward and is not in operation, the spring pushes the push rod 8 upward, creating a gap between the push rod 8 and the tappet 7, and the valve movement of the cam 6 is absorbed by this gap. It is designed so that the air is not transmitted to the intake and exhaust valves 9.

The valve mechanism of an internal combustion engine configured as described above is
Since two eccentric inner and outer bushes are used on the rocker shaft 4, the rocker arm 3 does not move horizontally but only moves vertically, and the rocker arm 3 and the push rod 8 do not come apart. The amount of movement of No. 3 is also sufficient, and it is an extremely excellent means for stopping the operation of intake and exhaust valves.

By the way, in the piston device 20 in the conventional valve mechanism, when the rod 21 is pushed down and the suction and exhaust valves 9 are in operation, the suction and exhaust valves 9 are connected to the rod 21 in operation, as shown in FIG. The piston 28 is connected to the cylinder 32 via the stopper 29.
The valve clearance is adjusted in a state where the valve contacts the lower cylinder 31 in which the bush 30 is housed and is prevented from moving downward.

For this reason, free parts occur in each part of the link device 10, causing play, and this play causes the link device 1 to
There was a problem that the 0 was worn out.

The purpose of this invention was to solve the above-mentioned problems with the conventional valve train.The piston device regulates the play of the link device, thereby eliminating wear of the link device and requiring no valve clearance adjustment. It is an object of the present invention to provide an excellent valve train mechanism for an internal combustion engine that can perform the following steps.

The internal combustion engine valve mechanism of this invention which achieves the above object has a rocker arm connected to the intake and exhaust valves,
A double bushing inserted into the locking shaft is provided so as to be freely displaceable between an operating state and a non-working state by eccentric rotation, and a link device connecting this double bushing and a piston device is set to the operating state of the locking arm. It is characterized in that it is energized by the moved piston device, and that a gap is provided between the piston and the cylinder in the piston sliding direction in the energized piston device. Note that parts that are the same as those in the conventional example are given the same numbers.

Embodiments of this invention will be described below with reference to the drawings.

FIG. 3 is a structural explanatory diagram, including a partial cross section, showing essential parts of a valve train for an internal combustion engine, showing an embodiment of this invention.

In this device, high-pressure air is supplied to the pipe 24 by a solenoid valve 23 (not shown), the pipe 25 is opened to the atmosphere, and the piston 28 is moved inside the cylinder 32 of the piston device 20 via the rod 21 and the link device 10. and outer bushes 1 and 2, and inner and outer bushes 1 and 2.
are rotated until the axes of each of them are aligned in a straight line, and the rocker arm 3 is brought into contact with the intake and exhaust valves 9 with the cam 6 on the base diamond, and in this state, the piston 28 of the piston device 20 between the lower end of the piston 2 and the cylinder 32
The cylinder 32 is extended so that a gap S is formed in the sliding direction of 8, and the piston 28 is configured to leave a margin of S in the stroke.

Therefore, in this invention, the piston 28, the rod 2
1. The link device 10 is always energized vertically downward when the intake and exhaust valves 9 are in operation, that is, when high-pressure air is supplied to the chamber 33 communicating with the pipe 24 of the cylinder 32. The pin 18 of the piston rod 21 is pressed against the lower side of the link hole 34, and the inner and outer bushes 1
The connecting pins 15 and 15' of 6 and 17 are pressed against the upper side of the link holes 35 and 36, respectively.

This prevents the pins 15, 15', 18 and the pin holes 34, 35, 36 from being worn out due to backlash, and allows for a large clearance between the pins and the pin holes. , it becomes possible to make the operation of the link device smooth.

In addition, in this design, as mentioned above, the valve clearance becomes 0 even when the suction and exhaust valves are closed due to the margin S of the piston stroke, but the elongation due to thermal expansion of the suction and exhaust valves, etc. There is no problem because it is absorbed by compressing the air.
Therefore, the valve operating mechanism of this invention does not require valve clearance adjustment.

As explained above, the present invention provides a rocker arm connected to an intake/exhaust valve that can be freely displaced between an operating state and a non-operating state by eccentric rotation of a double bushing inserted into a rocker shaft. The link device that connects the double bushing and the piston device is energized by the piston device that has been moved to the operating state of the rocker arm, and the piston device that is being energized has the piston sliding direction that occurs between the piston and the cylinder. Although the double bushing and the piston device are connected by a link device, the backlash of this link device can be eliminated by the gap between the piston and the cylinder when the rocker arm is moved to the operating state. By regulating the force of the piston device with a gap between them, it is possible to prevent the wear of various parts due to the play of the backlash of the link device, and there is no need to adjust the clearance of the intake and exhaust valves connected to the rocker arm. You can also do this.

[Brief explanation of the drawing]

Fig. 1A is a side view of the rocker arm attached to the rocker shaft via a double eccentric bush, and Figure 1C is a side view of the rocker arm of Fig. 1A with the eccentric bushes rotated in opposite directions. Fig. 1B is an explanatory diagram of the configuration of a conventional variable cylinder engine valve mechanism using the rocker arm of the same A, Fig. 2 is a half-sectional view of a conventional piston device of the mechanism shown in Fig. 1, and Fig. 3 FIG. 2 is a configuration explanatory diagram, including a partial cross section, showing a main part of a valve mechanism for an internal combustion engine according to the present invention. 1... Inner bush, 2... Outer bush, 3... Locker arm, 4... Locker shaft, 7... Tappet, 8... Button rod, 9
...Suction, exhaust valve, 10...Link device, 16,1
7... Link, 20... Piston device, 21...
Rod, 23... Solenoid valve, 28... Piston, 2
9...Stopper, 30...Butsuyu, 31...Lower cylinder, 32...Cylinder.

Claims (1)

[Scope of utility model registration request] A rocker arm connected to the intake/exhaust valve is provided so as to be freely displaceable between an operating state and a non-operating state by eccentric rotation of a double bushing inserted into a rocker shaft, and a connection is made between this double bushing and a piston device. A valve train for an internal combustion engine, in which a link device is energized by a piston device that has been moved to an operating state of a rocker arm, and a gap is provided in the energized piston device in the piston sliding direction between the piston and the cylinder. mechanism.