JPS6321682Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an intake/exhaust valve actuation stop device used to stop operation of some cylinders during low (medium) load in order to improve fuel efficiency.

In order to improve the fuel efficiency of an engine, a device is known that stops the supply of fuel to some cylinders at low (medium) loads and also stops the operation of the intake and exhaust valves of those cylinders.

As an intake/exhaust valve operation stop device, for example, as disclosed in Japanese Patent Application Laid-Open No. 54-57009, a tappet lifted by a cam is hydraulically operated, and the valve is operated by supplying lubricating oil to the hydraulic chamber. Generally, the operation of the valve is stopped by stopping the supply.

However, when using this type of hydraulic tappet, the pressure of the lubricating oil supplied to the hydraulic chamber changes depending on the engine rotation, so when the valve is operated and the oil pressure is low at low engine speeds, The maximum lift amount will be reduced.

Furthermore, even if the hydraulic chamber is opened in order to stop the operation of the valve, there is a problem that the valve does not stop immediately even if the valve is opened because lubricating oil is constantly supplied to this device.

As described above, the present invention aims to provide a valve operation stop device that causes no lift loss when the valve is operated and can immediately shift to the stopped state when the valve is stopped.

Hereinafter, the present invention will be explained with reference to an illustrated embodiment.

1 is a cam, 2 is a tappet, 3 is a push rod, 4 is a rocker arm, and 5 is an intake and exhaust valve. The tappet 2, which is lifted by the cam 1, is inserted into a tappet hole 61 of the cylinder block 6, and has a receiving plate part 21 in the upper part of which the push rod 3 is abutted and engaged, and a recessed part 22 connected to the receiving plate part 21. is formed. In addition, the saucer part 21
The tray portion 21 of the stepped portion 23 that communicates with the recessed portion 22
It is preferable that the height h of the twist is less than the valve gap. Further, the outer periphery of the upper part of the tappet 2 is shaped into an ellipse formed by combining two circles, and is inserted into the tappet hole 61, thereby preventing the tappet 2 from rotating.

Reference numeral 7 denotes a holding means, which consists of a spring 73 attached between a plate 71 attached to the upper part of the push rod 3 and a plate 72 attached to the rocker arm 4 by an Asiast screw 41 and its nut 42; The spring 73 urges the push rod 3 in the direction of the rocker arm 4 to keep them engaged with each other. Reference numeral 8 denotes a switching means, which includes a ring 81 attached to the outer periphery of the push rod 3 with an appropriate gap, an actuation cylinder 83 having a piston 83a connected to this ring 81 via a rod 82, and this actuation cylinder 83.
It consists of a three-way solenoid valve 85 that shuts off high-pressure air from the air tank 84 to the piston 83a. actuates against the biasing force of the spring 83b to move the push rod 3 from the receiving tray portion 21 to the recessed portion 22 position as shown by the two-dot chain line in FIG. 9 is a spring that urges the tappet 2 in the cam 1 direction; 10 is a valve spring;
11 is a rocker shaft, 12 is a spring that biases the rocker arm 4 in the direction of the valve 5, and B is a power source.

In the above configuration, when the engine load is (medium) high, high pressure air is not supplied to the operating cylinder 83, so that the switching means 8 positions the push rod 3 on the receiving tray portion 21 of the tappet 2.

As a result, the operation of the cam 1 is transmitted via the tappet 2, push rod 3 and rocker arm 4 to the intake and exhaust valves 5 to open and close them.

Next, when the engine load becomes a low (medium) load state, the load switch 86 supplies high pressure air from the air tank 84 to the operating cylinder 83 via the three-way solenoid valve 85.

As a result, the piston 83a moves the lower end of the push rod 3 through the link 82 to the recess 22 position as indicated by the two-dot chain line in the figure.

Therefore, although the cam 1 lifts the tappet 2, its operation is absorbed by the recess 22 and is not transmitted to the push rod 3. Therefore, the intake/exhaust valve 5 is biased by the valve spring 10 and remains closed and stops operating.

In addition, even in this state, the push rod 3
There is no problem because the retaining means 7 including the spring 73 maintains the engaged state with the Asiast screw 41, and the tappet 2 is urged in the direction of the cam 1 by the spring 9 to maintain the engaged state with the cam 1. .

As described above, the present invention forms a recess 22 in the tapepet 2 that is connected to the receiving tray 21 with which the push rod 3 is brought into contact, and the push rod 3 is positioned in the receiving tray 21 and the recess 22 by the switching means 8. Since the operation of the exhaust valve 5 is made intermittent, there is no response delay when the exhaust valve is turned on and off compared to the conventional hydraulic tappet system, and no lift loss occurs during operation.

In this embodiment, the switching means is based on fluid (air) pressure, but the switching means may be one that operates externally electromagnetically.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional front view showing an embodiment of the present invention, FIG. 2 is an enlarged side view showing a tappet, and FIG. 3 is a view taken along arrow A in FIG. 1; cam, 2; tappet, 21; saucer part, 2
2; recessed portion; 3; push rod; 4; rocker arm; 5; intake and exhaust valve; 7; holding means; 8; switching means.

Claims (1)

[Scope of utility model registration request] A recess connected to a receptacle part for bringing the push rod into contact with the upper part of the tappet lifted by the cam, a switching means for movable the push rod between the receptacle part and the recess position, and a rocker arm for moving the push rod. The intake and exhaust valve actuation is characterized in that holding means are provided, each holding means is biased in the direction to maintain the mutually engaged state, and the push rod is moved to the recessed position to stop the operation of the valve. Stop device.