JP2503935B2 - Engine valve train - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 condition of the engine.

[0002]

2. Description of the Related Art An automobile does not need such a power when it is traveling on a general road, and only needs to use half of the power of an engine installed therein. Therefore, in such an operating state, it is possible to save energy by stopping a part of the engine (cylinder deactivation) to reduce an extra output. Therefore, in a multi-cylinder engine, the valve mechanism of the cylinder to be stopped is stopped and the fuel supply is also stopped. For example, in the case of a 4-cylinder engine, half of the two cylinders are stopped (cylinder deactivation). There is a cylinder engine. In such a variable cylinder engine, the rocker arm of the cylinder for which the function of the valve operating mechanism is desired to be stopped is idled to stop the movement of the intake and exhaust valves.

FIGS. 5 and 6 show an example of the intake valve side of a valve mechanism of a four-valve variable cylinder engine, in which a rocker shaft 1 is rotatably fitted with a base end 2a 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. Rocker arm 2
A roller 5 is rotatably supported at the tip of the roller.
The cam 6 is rollably abutted. Further, the tips 3b and 4b of the rocker arms 3 and 4 are respectively connected to the stem head 9 of each intake valve 9 via the adjusting screws 7 and 8, respectively.
a (only one valve is shown in FIG. 5).

As shown in FIG. 5, piston holes (hereinafter simply referred to as “holes”) 1a and 2c are bored in the rocker shaft 1 and the rocker arm 2, respectively. The rocker shaft 1 and the rocker arm 2 have piston holes 1a and 2c, respectively. 13 is slidably inserted 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 the hydraulic pressure is not applied, the piston 13 is pushed out of the hole 1a by the spring force of the spring 14 and the tip of the piston 13 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, cam 6
The rocker arms 3 and 4 swing via the rocker arm 2 and the rocker shaft 1 to drive the valves 9 in accordance with the rotation.

The piston 13 is hydraulically actuated to a spring 14
When the rocker arm 2 is pushed into the hole 1a against the spring force, the tip of the rocker arm 2 is disengaged from the hole 2c and the rocker arm 2 and the rocker shaft 1 are disconnected. As a result, the rocker shaft 1 becomes free with respect to the rocker arm 2, and even if the rocker arm 2 rocks as the cam 6 rotates, the rocker arms 3 and 4 are stopped without rocking, and each valve 9 is It is held in a stopped (valve closed) state. 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 resting.

[0006]

However, in the valve 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 separated from each other. The rocker shaft 1 rotates with the rocker arm 2 due to the frictional force between the rocker shaft 1 and 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 jump up. In the descending section of the cam 6, the rocker shaft 1 rotates, and the phase between the hole 2c of the rocker arm 2 and the piston 13 remains deviated. This deviation is maintained even in the base circle section 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 can be smoothly returned from the stopped state to the operating state. However, there is a problem in that it may be impossible to recover depending on the situation.

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

[0008]

To achieve the above object, according to the present invention, there is provided a first rocker arm having a distal end abutting a cam and a proximal end pivotally supported by a rocker shaft.
Pistons that are fitted into piston holes formed in the diametrical direction at the base ends of the rocker shaft and rocker arm respectively to connect or disconnect them, and the base end is fixed to the rocker shaft and the tip abuts the stem head of the valve. In a valve operating mechanism of an engine including a second rocker arm, the tip of the second rocker arm is interposed between a tip end side of the second rocker arm and a portion irrelevant to the movement of the valve operating mechanism. The structure is such that a spring for pressing the stem head is provided.

[0009]

The tip of the second rocker arm is constantly pressed against the stem head of the valve by the 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 is easily fitted into the piston hole of the first rocker arm. It becomes possible. As a result, the cylinder deactivated state can be smoothly restored to the operating state.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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. In FIG. 1 and FIG. 2, rocker arms 3, 4 having base ends 3a, 4a fixed thereto
One of these, for example, a support portion 20 is provided at a position slightly above the base end 3a of the rocker arm 3, and this support portion 20 has a portion irrelevant to the movement of the valve operating mechanism, for example, the valve operating mechanism. It is formed integrally with a cylinder head (not shown) provided. The spring 21 is, for example, a strip-shaped leaf spring, the base end of which is fixed to the end surface of the support portion 20 by a bolt 22, which is curved near the base end and extends in the direction of the tip 3b along the upper surface 3c of the rocker arm 3. The tip is pressed against the approximate center of the upper surface 3c.

This spring 21 is provided on the upper surface 3 of the rocker arm 3.
By pressing c, the rocker arm 3 and the rocker arm 4 concerned
Is pressed so as to rotate clockwise about the rocker shaft 1. 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 the hydraulic pressure is not applied, the piston 13 is pushed out from the hole 1a of the rocker shaft 1 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 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 resists the spring force of the spring 14 by hydraulic pressure and the hole 1 of the rocker shaft 1
It is pushed into the hole a, and its tip is the hole 2 of the rocker arm 2.
Deviates from c. 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 rocks as the cam 6 rotates, the rocker arms 3 and 4 rock. It remains stopped without moving, and each valve 9 is held in a stopped (valve closed) state. Therefore, these valves 9
The cylinder is 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. In addition, the rocker arms 3 and 4 have their tips 3b,
Since 4b is pressed against the stem head of each valve 9, the cam 6 is prevented from jumping up in the descending section, 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 in the base circle section of the cam 6 when the cylinder is resting
The piston 13 and the piston 13 are held in a matched state, and the tip of the piston 13 can be fitted into the hole 2c of the rocker arm 2. 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 in place of the spring 21, and a rocker arm is provided in the support portion 20. 3, a hole 20a is vertically formed facing the tip 3b of the rocker arm 3 above the rocker arm 3.
A cylinder 24 is fitted to the cylinder 24 with its open end facing downward, and a cylinder 25 is fitted to the cylinder 24 so as to be slidable in the axial direction with its closed end facing downward. A spring 26 is provided in a contracted manner between the spring 26 and 25.

A protrusion 25a protruding in the center of the closed end surface of the cylinder 25 is pressed against a boss 3d protruding near the tip 3b of the upper surface 3c of the rocker arm 3. The cylinder 25 applies a pressing force that causes the rocker arms 3 and 4 to rotate clockwise in the drawing by the spring force of the spring 26. This prevents the rocker arms 3, 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 operating mechanism shown in FIG. 4 uses a tension spring 27 in place of the spring 21 shown in FIG. 3, and the tension spring 27 has a support portion whose one end is provided below the rocker arm 3. 20 ', and the other end is locked in 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. 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 this embodiment, the case where the invention is applied to the valve operating mechanism of the variable cylinder engine is described, but the 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 a valve operating mechanism.

[0019]

As described above, according to the present invention, the first rocker arm having the distal end in contact with the cam and the proximal end pivotally supported by the rocker shaft, and the proximal end of the rocker shaft and 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 of the engine, provided is a spring interposed between the distal end side of the second rocker arm and a portion irrelevant to the movement of the valve operating mechanism, for pressing the distal end of the second rocker arm against the stem head. Due to the structure, the rocker shaft and the first
The piston holes of the rocker arm of the locker arm are prevented from shifting, and the piston that is pulled into the piston hole of the rocker shaft can be easily fitted into the piston hole of the first rocker arm, returning from cylinder deactivation to full cylinder operation. Alternatively, it is possible to smoothly change the valve timing and the like.

[Brief description of drawings]

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

FIG. 2 is a plan view of FIG.

FIG. 3 is a cross-sectional view of essential parts 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

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Murata 5-3-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor Kiyuki Miyamura 5-3-8 Shiba, Minato-ku, Tokyo Within Mitsubishi Motors Corporation

Claims (1)

(57) [Claims] 1. A first rocker arm having a tip abutting against a cam and a base end rotatably supported by a rocker shaft, and piston holes diametrically bored at the rocker shaft and the base end of the rocker arm, respectively. A second rocker arm having a base end fixed to the rocker shaft and a distal end abutting on a stem head of the valve;
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. .