JPH0510719U - Engine valve mechanism - Google Patents

Abstract

(57) [Summary] [Purpose] It is easy to return from a cylinder deactivation operation to a full cylinder operation or to change the valve timing of a valve operating mechanism that can change cylinder deactivation or valve timing. [Structure] A rocker arm 2 whose front end abuts on a cam 6 and whose base end is rotatably supported by a rocker shaft 1, and piston holes 1a and 2c which are diametrically formed at the base ends of the rocker shaft and rocker arm. A tip end 3b of the rocker arm 3 of the engine valve mechanism including a piston 13 that is fitted to couple or release the two, and a rocker arm 3 whose base end is fixed to a rocker shaft and whose tip end contacts the stem head 9a of the valve. A spring 21 is provided between the side and a portion 20 unrelated to the movement of the valve mechanism to press the rocker arm 3 against the stem head 9a.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an engine valve operating mechanism, and more particularly to an engine valve operating mechanism suitable for an engine capable of changing the cylinder deactivation or valve timing according to the operating state of the engine.

[0002]

[Prior Art]

 A car does not need that much power when traveling on a general road, and it is sufficient if it uses half of the power of the engine installed. Therefore, in such an operating state, it is possible to save energy by stopping a part of the engine (deactivating the cylinder) to reduce an excessive output. Therefore, in a multi-cylinder engine, the valve operating mechanism of the cylinder to be stopped is stopped, and also the fuel supply is stopped. For example, in the case of a 4-cylinder engine, half of the two cylinders are stopped (cylinder deactivation). There is a variable cylinder engine. In such a variable cylinder engine, the rocker arm of the cylinder for which the valve mechanism function is desired to be stopped is oscillated to stop the intake / exhaust valve movement.

FIGS. 5 and 6 show an example of the intake valve side of a valve mechanism of a 4-valve variable cylinder engine, in which a rocker shaft 1 is rotatably fitted with a base end 2 a of a rocker arm 2. Further, the base ends 3a and 4a of the two rocker arms 3 and 4 are fitted and fixed on both sides of the base end 2a of the rocker arm 2 of the rocker shaft 1. A roller 5 is pivotally supported at the tip of the rocker arm 2, and the roller is rotatably abutted on a cam 6. The tips 3b and 4b of the rocker arms 3 and 4 are in contact with the stem heads 9a of the intake valves 9 (only one valve is shown in FIG. 5) via the adjusting screws 7 and 8, respectively.

As shown in FIG. 5, piston holes (hereinafter simply referred to as “holes”) 1 a and 2 c are bored in the rocker shaft 1 and the rocker arm 2, respectively, and the rocker shaft 1 and the rocker shaft 1 are bored in the hole 1 a. The piston 13 is slidably fitted in the axial direction, and a spring 14 is contracted between the base end of the piston 13 and the open end on one side of the hole 1a. When no hydraulic pressure is applied, the piston 13 is pushed out of the hole 1a by the spring force of the spring 14, and its tip is fitted into the hole 2c of the rocker arm 2 to connect the rocker arm 2 and the rocker shaft 1. As a result, as the cam 6 rotates, the rocker arms 3 and 4 swing via the rocker arm 2 and the rocker shaft 1 to drive the valves 9.

When the piston 13 is pushed into the hole 1a against the spring force of the spring 14 by hydraulic pressure, the tip of the piston 13 is disengaged from the hole 2c of the rocker arm 2 and the connection between the rocker arm 2 and the rocker shaft 1 is released. To be done. As a result, the rocker shaft 1 becomes free with respect to the rocker arm 2, and even if the rocker arm 2 swings as the cam 6 rotates, the rocker arms 3 and 4 stop without swinging, and each valve 9 , It is kept stopped (valve closed). Therefore, the cylinders of these valves 9 are stopped (deactivated). Further, the lost motion assembly 16 prevents the rocker arm 2 from jumping up when the cylinder is stopped.

[0006]

[Problems to be solved by the device]

 However, in the valve operating mechanism having the above structure, when the valve 9 is in a stopped state, that is, when the tip of the piston 13 is disengaged from the hole 2c of the rocker arm 2, the rocker arm 2 and the rocker shaft 1 are rubbed by the frictional force. The shaft 1 rotates with the rocker arm 2. That is, since the rocker arms 3 and 4 integrated with the rocker shaft 1 are restricted by the valve end in the ascending section of the cam 6, the rocker shaft 1 does not rotate, but the rocker arms 3 and 4 are free to move up. Therefore, the rocker shaft 1 rotates in the descending section of the cam 6, and the phase between the hole 2c of the rocker arm 2 and the piston 13 remains deviated. This deviation is maintained even between the base circles of the cam 6, and it becomes difficult to fit the piston 13 into the hole 2c of the rocker arm 2, and as a result, the valve 9 is smoothly returned from the stopped state to the operating state. It becomes extremely difficult, and in some cases it may not be possible to recover.

The present invention has been made in view of the above-mentioned points, and in the engine capable of changing the cylinder deactivation or the valve timing, the valve operating mechanism returns from the cylinder deactivation operation to the all cylinder operation, or the valve timing. The purpose of the present invention is to provide an engine valve mechanism that can smoothly change the engine.

[0008]

[Means for Solving the Problems]

 To achieve the above object, according to the present invention, there is provided a first rocker arm having a tip abutting a cam and a base end rotatably supported by a rocker shaft, and a diameter of the rocker shaft and the rocker arm. Engine equipped with a piston that is fitted in a piston hole that is bored in the direction to connect or disconnect the two, and a second rocker arm whose base end is fixed to the rocker shaft and whose tip contacts the stem head of the valve In the valve operating mechanism, a spring is provided which is interposed between the tip end side of the second rocker arm and a portion unrelated to the movement of the valve operating mechanism and presses the tip end of the second rocker arm to the stem head. It is structured.

[0009]

[Action]

 The tip of the second rocker arm is constantly pressed against the stem head of the valve by a spring to prevent the second rocker arm from jumping up when the cylinder is inactive. As a result, the piston holes of the first rocker arm and the rocker shaft are always kept in alignment with each other when the cylinder is deactivated, and the piston pulled into the pitsun hole of the rocker shaft can be easily inserted into the piston hole of the first rocker arm. Mating is possible. This allows a smooth return from the cylinder deactivated state to the operating state.

[0010]

【Example】

 An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The same members as those in FIGS. 5 and 6 are designated by the same reference numerals, and detailed description thereof will be omitted. 1 and 2, a support portion 20 is provided at one of the rocker arms 3 and 4 to which the base ends 3a and 4a are fixed, for example, slightly above the base end 3a of the rocker arm 3. The support portion 20 is integrally formed with a portion unrelated to the movement of the valve mechanism, for example, a cylinder head (not shown) in which the valve mechanism is arranged. The ridge 21 is, for example, a strip-shaped leaf spring, the base end of which is fixed to the end face of the support portion 20 by a bolt 22 and which curves near the base end and extends along the upper surface 3c of the rocker arm 3 to the tip 3b. And extends in the direction, and the tip is pressed into contact with substantially the center of the upper surface 3c.

The spring 21 presses the upper surface 3 c of the rocker arm 3 to press the rocker arm 3 and the rocker arm 4 so as to rotate clockwise around the rocker shaft 1 in the figure. The initial load of the spring 21 is set to a value larger than the torque due to the frictional force between the rocker arm 2 and the rocker shaft 1 to prevent the rocker shaft 1 from being rotated by the rocker arm 2. There is.

When no hydraulic pressure is applied, the piston 13 is pushed out of the hole 1 a of the rocker shaft 1 by the spring force of the spring 14, and its tip is fitted into the hole 2 c of the rocker arm 2 to connect the rocker arm 2 and the rocker shaft 1 to each other. To do. As a result, as the cam 6 rotates, the rocker arms 3 and 4 swing via the rocker arm 2 and the rocker shaft 1 to drive the valves 9.

When the cylinder is inactive, the piston 13 is pushed into the hole 1 a of the rocker shaft 1 by the hydraulic pressure against the spring force of the spring 14, and the tip of the piston 13 is disengaged from the hole 2 c of the rocker arm 2. As a result, the connection between the rocker arm 2 and the rocker shaft 1 is released, the rocker shaft 1 becomes free with respect to the rocker arm 2, and even if the rocker arm 2 swings as the cam 6 rotates, the rocker arms 3 and 4 are The valve 9 remains stopped without swinging, and each valve 9 is held in a stopped (valve closed) state. Therefore, the cylinders of these valves 9 are stopped (deactivated).

In the ascending section of the cam 6, the rocker arms 3 and 4 integrated with the rocker shaft 1 are restricted to the valve ends, so that the rocker shaft 1 does not rotate. Further, the rocker arms 3 and 4 are prevented from jumping up in the descending section of the cam 6 because the tips 3b and 4b are pressed against the stem heads of the valves 9 by the spring force of the spring 21, and therefore, The rocker shaft 1 is prevented from being rotated by the rocker arm 2. As a result, the hole 2c of the rocker arm 2 and the piston 13 are held in a matched state in the base circle section of the cam 6 at the time of cylinder deactivation, and the piston 13 can be fitted into the hole 2c of the rocker arm 2 at its front end. It is in a state. This makes it possible to smoothly return the valve 9 from the stopped state to the operating state.

3 and 4 show another embodiment of the present invention. In the valve mechanism shown in FIG. 3, a compression spring 26 is used instead of the spring 21. A hole 20a is vertically formed at a position above the rocker arm 3 so as to face the vicinity of the tip 3b of the rocker arm 3, and a cylinder 24 is fitted in the hole 20a with its open end facing downward. A cylinder 25 is fitted in the cylinder 24 so as to be slidable in the axial direction with its closed end facing downward, and a spring 26 is contracted between the cylinders 24 and 25.

A protrusion 25 a protruding in the center of the closed end surface of the cylinder 25 is pressed against a boss 3 d protruding near the tip 3 b of the upper surface 3 c of the rocker arm 3. The cylinder 25 applies a pressing force by the spring force of the spring 26 so as to rotate the rocker arms 3 and 4 in the direction of the timepiece in the figure. This prevents the rocker arms 3 and 4 from jumping up in the descending section of the cam 6 of the rocker arms 3 and 4, and prevents the rocker shaft 1 from being rotated by the rocker arm 2.

The valve mechanism shown in FIG. 4 uses a tension spring 27 in place of the spring 21 shown in FIG. 3, and one end of the tension spring 27 is provided below the rocker arm 3. The rocker arm 3 is locked to the portion 20 ', and the other end is locked to a small hole 3e formed near the lower end of the rocker arm 3. The tension spring 27 applies a pressing force to rotate the rocker arm 3 in the clockwise direction in the figure, as in the above description. As a result, the rocker arms 3 and 4 are prevented from jumping up in the descending section of the cam 6 at the time of cylinder deactivation, and the rocker shaft 1 is prevented from being rotated by the rocker arm 2.

In the present embodiment, the description has been given of the case where it is applied to the valve operating mechanism of the variable cylinder engine, but the present invention is not limited to this, and the valve timing can be changed according to the operating state of the engine. It can also be applied to various valve operating mechanisms.

[0019]

[Effect of the device]

 As described above, according to the present invention, the first rocker arm having the tip abutting on the cam and the base end rotatably supported by the rocker shaft, and the rocker shaft and the base end of the rocker arm each have a diametrical direction. Of the engine equipped with a piston that is fitted into a piston hole that is bored in the piston to connect or disconnect them, and a second rocker arm whose base end is fixed to the rocker shaft and whose tip contacts the stem head of the valve. In the valve mechanism, there is provided a spring interposed between the tip end side of the second rocker arm and a portion irrelevant to the movement of the valve mechanism, and for providing a spring for pushing the tip end of the second rocker arm to the stem head. As a result, the piston holes of the rocker shaft and the first rocker arm are prevented from being displaced in the base circle section of the cam when the cylinder is resting, and the piston hole inside the rocker shaft is prevented. The retracted piston can be easily fitted into the piston hole of the first rocker arm, and it is possible to smoothly return from cylinder deactivation operation to full cylinder operation or change the valve timing. is there.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a valve operating mechanism of an engine according to the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a sectional view of an essential part showing another embodiment of the valve operating mechanism of the engine according to the present invention.

FIG. 4 is a cross-sectional view of essential parts showing another embodiment of the valve operating mechanism for the engine according to the present invention.

FIG. 5 is a partial cross-sectional view of a conventional engine valve mechanism.

FIG. 6 is a plan view of FIG.

[Explanation of symbols]

 1 rocker shaft 2, 3, 4 rocker arm 6 cam 9 valve 20, 20 'support portion 21, 26, 27 spring

Front page continuation (72) Shinichi Murata 5-3-8 Shiba, Minato-ku, Tokyo Within Mitsubishi Motors Corporation (72) Inventor Kiyuki Miyamura 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation Stock In the company

Claims (1)

[Claims for utility model registration] [Claim 1] A first rocker arm having a tip abutting against a cam and a base end rotatably supported by a rocker shaft, and a diameter at each of the rocker shaft and the base end of the rocker arm. And a second rocker arm whose proximal end is fixed to the rocker shaft and whose distal end abuts the stem head of the valve. In the valve operating mechanism, the second
A valve operating mechanism for an engine, comprising a spring interposed between the tip end side of the rocker arm and a portion irrelevant to the movement of the valve operating mechanism for pressing the tip end of the second rocker arm to the stem head. .