JPH04134110A - Variable cylinder device - Google Patents

Abstract

PURPOSE:To simplify structure as well as to get rid of any nonconformity such as the occurrence of operation failure due to air mixture into a hydraulic circuit by making a variable cylinder device composable by way of adding a second cam in addition to an ordinary valve driving cam. CONSTITUTION:At the time of usual operation of an engine, a cam 25 is at a standastill in an illustrated position, and a rocker arm 21 rockes with its one end 21b as a fulcrum point with rotation of a cam 24. Accordingly, a valve 14 opens or closes a passage 12 by doing the vertical motion. On the other hand, at time of low load operation, the cam 25 is rotated as far as about 180 deg. by a transfer shaft 26, and it is no longer driven by a second rocker arm 21 and the cam 24. At this time the rocker arm 21 is shifted downward with the one end 21b as the fulcrum point, so that the valve 14 separates from a valve seat 13. However, the valve 14 soon comes into contact with the valve seat 13 by dint of energizing force of a spring 19, whereby a piston 23 of a hydraulic lifter 22 is shifted downward, thus the passage 12 is fully closed and the cylinder converted is made into a nonoperative state.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a variable cylinder device, and is used, for example, as a device for varying the number of operating cylinders of an engine having a plurality of cylinders. .

(Prior art) As a prior art related to the present invention, for example,
There is one disclosed in Japanese Patent No.-68133. This prior art will be explained based on FIGS. 4 and 5. A piston 72 is slidably disposed in a cylinder block 71 of a multi-cylinder engine 70, and a passage 74 is formed in a cylinder head 73.

A valve seat 75 is disposed in the passage 74, and a valve 76 that comes into contact with and separates from the valve seat 75 freely opens and closes the passage 74. The valve 76 is connected to the cylinder head 73 by the guide 7.
7, and its upper end as shown in the figure is fixed to a bracket 78. A spring 79 is disposed between the spring 78 and the cylinder head 73, and urges the valve 76 in the direction of contacting the valve seat 75.

The upper end of the tip 78 is engaged with one end 81a of the rocker arm 81 via the plate 80, and the other end 81b is engaged with the upper end of the piston 83 of the hydraulic lifter 82. Further, a cam 84 rotated by a shaft (not shown) is engaged with a substantially central portion of the rocker arm 81.

The housing 85 of the hydraulic lifter 82 is connected to the cylinder block 7
3, and a piston 83 is slidably accommodated in a hole 86 formed therein. piston 8
A pressure chamber 87 formed between the lower end of 3 and the lower end of hole 86
A spring 88 is tensioned between the flange 83b of the piston 83 and the upper end of the housing 85, and a spring 91 is tensioned between the flange 83b of the piston 83 and the upper end of the housing 85. There is.

Further, an oil storage chamber 89 is formed inside the piston 83, and communicates with the pressure chamber 87 via a check valve mechanism 90 through a communication hole 83a formed at the lower end of the piston 83. Further, the oil storage chamber 89 communicates with a hydraulic power source (not shown) via a hydraulic pressure supply path 91, and is constantly supplied with high pressure oil. On the other hand, the pressure chamber 87 communicates with an oil pan (not shown) via a hydraulic discharge path 92 and a switching valve (not shown).

In the above, when the switching valve is closed during normal operation of the engine, high pressure oil is sealed in the pressure chamber 87, and the piston 83 does not slide within the hole 86. Therefore, since the rocker arm 81 is swung by the cam 84 using its one end 81b as a fulcrum, the valve 76 repeatedly moves up and down. That is, the valve 76 opens and closes the passage 74.

Now, when the engine is operated under low load, the switching valve is opened, and the supply oil in the pressure chamber 87 can freely flow out to the oil pan, and the check valve 90 is also opened and closed accordingly. Therefore, since the piston 83 can freely slide within the hole 86, the rocker arm 81 is swung by the cam 84 using its one end 81a as a fulcrum.

Therefore, valve 76 does not open or close passageway 74.

This allows the number of operating cylinders to be varied when the multi-cylinder engine 70 is under low load, thereby improving fuel efficiency and reducing environmental pollution.

(Problem to be Solved by the Invention) However, in the above-mentioned conventional technology, additional configurations such as a hydraulic discharge passage 92 and a switching valve are required for the ordinary hydraulic lifter, and forming the hydraulic discharge passage in particular requires a large manufacturing process. Since the number of man-hours increases, an increase in costs is inevitable. Furthermore, if air gets mixed into the hydraulic circuit, there is a risk that the valve will not be able to stop properly when the engine is operating at low load.

Therefore, the technical object of the present invention is to easily configure a variable cylinder device without using a new hydraulic circuit.

[Structure of the invention]

(Means for Solving the Problems) The technical means of the present invention taken to solve the above-mentioned technical problems of the present invention is to combine a variable cylinder device with a housing,
A passage formed in the housing, a valve that freely opens and closes the passage, a spring that biases the valve in a direction in which the passage closes, a first cam that biases the valve in the opening direction via one end of the rocker arm, and a rocker arm. It is composed of a hydraulic lifter that engages with the other end and a second cam that engages with the rocker arm, and the first cam and the rocker arm are engaged or disengaged depending on the rotational position of the second cam. This is to ensure that

(Function) According to the above-mentioned technical means of the present invention, a variable cylinder device can be easily constructed by simply adding a second cam in addition to the normal valve drive cam (first cam). Also, problems such as malfunctions caused by air entering the hydraulic circuit do not occur.

(Example) An example embodying the technical means of the present invention will be described below based on the accompanying drawings.

In FIGS. 1 to 3, a variable cylinder device 10 is used in a multi-cylinder engine (not shown), and the cylinder rad 11 has passages (intake and exhaust passages) 1 for the same number of cylinders.
2 is formed. A valve seat 13 is located above the passage 12.
is arranged so that the valve 14 can be brought into contact with and separated from it.

The valve 14 is slidably supported on the cylinder rod 11 via a guide 15, and allows the passage 12 to be opened and closed.

Further, a seal 20 is provided at the upper end of the guide 15.

The valve stem 16 is formed integrally with the valve 14, a valve stem 17 is fitted near the upper end thereof, and a plate 18 is fixed to the outer periphery of the valve stem 16. Further, a spring 19 is stretched between the lower end of the recess 11a of the cylinder block 11 and the plate 18, and urges the valve 14 toward the valve seat 13.

One end 21a of a rocker arm 21 is engaged with the illustrated upper end of the valve stem 16, and a piston 23 of a known hydraulic lifter 22 is engaged with the other end 21b.

Two cams 24 and 25 are engaged with the upper surface of the rocker arm 21, and the cam 24 is integrated with a camshaft (not shown) for driving the valve 14, and the cam 25 is integrated with a switching shaft 26 for the variable cylinder. There is.

The operation of the variable cylinder device 10 having the above configuration will be described below.

During normal operation of the multi-cylinder engine, the cam 25 is stationary at the position shown in FIG. 1, and as the cam 24 rotates, the rocker arm 21 swings about its one end 21b as a fulcrum.

Therefore, the valve 14 opens and closes the passage 12 by moving up and down. Since this passage 12 is an intake/exhaust passage, an air-fuel mixture or exhaust gas flows therethrough.

Now, when the multi-cylinder engine is operated under low load, the cam 25 is first rotated by the switching shaft 26 and becomes in the state shown in FIG. In this state, the cam 24 cannot be engaged with the rocker arm 21. Therefore, rocker arm 21 is not driven by cam 24. At this time, since the rocker arm moves downward in the figure using its one end 21b as a fulcrum, the valve 14 separates from the valve seat 13 as shown in FIG.

However, since the biasing force of the spring 19 is greater than the biasing force of the hydraulic lifter 22, the state eventually changes to the state shown in FIG. 3. That is, the valve 14 comes into contact with the valve seat 13, the rocker arm moves downward in the figure using its one end 21a as a fulcrum, and the piston 23 of the hydraulic lifter 22 moves downward in the figure.

In this state, the passage 12 is completely closed, so the air-fuel mixture is not supplied to the cylinder (not shown), and the cylinder does not operate. The number of cylinders that do not operate can be set to an arbitrary number, and the number is not particularly limited.

[Effects of the Invention] As described above, in the present invention, a normal valve driving cam (
By simply adding a second cam in addition to the first cam), a variable cylinder device can be easily constructed, and problems such as malfunctions due to air being mixed into the hydraulic circuit do not occur.

Further, since the configuration of the present invention is only added to the cylinder head, it is also excellent in mounting on conventional engines.

[Brief explanation of the drawing]

FIG. 1 shows a cross-sectional view of a variable cylinder device IO according to an embodiment of the present invention during normal engine operation. FIG. 2 shows a sectional view of the variable cylinder device 10 in its initial state during low engine load operation. FIG. 3 shows a sectional view after a certain period of time in FIG. 2 has elapsed. FIG. 4 shows a sectional view of a prior art variable cylinder device. FIG. 5 shows an enlarged sectional view of the main part in FIG. 4. 10... Variable cylinder device, 11... Cylinder head (housing), 12...
Passage, 14... Valve, 19... Spring, 21... Rocker arm, 22... Hydraulic lifter, 24... First cam, 25... Second cam.

Claims (1)

[Scope of Claims] A housing, a passage formed in the housing, a valve that opens and closes the passage, a spring that biases the valve in a direction in which the passage is closed, and a spring that biases the valve to close one end of a rocker arm. a hydraulic lifter that engages with the other end of the rocker arm; and a second cam that engages with the rocker arm; A variable cylinder device characterized in that the first cam and the rocker arm are engaged and disengaged.