JP2638974B2 - Valve forced opening and closing device for internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a valve forcible opening / closing device for forcibly opening and closing an intake / exhaust valve of an internal combustion engine.

(Prior art and problems) In order to improve the followability of the intake and exhaust valves during high-speed rotation of the engine, a cam for opening and closing the cam is formed on the camshaft to forcibly open the intake and exhaust valves. A valve operating device for closing a valve is known.

Conventionally, as such a valve train, for example, Japanese Unexamined Patent Publication No.
No. 12 and JP-A-60-32910, respectively, disclose a rocker arm for closing a valve and a rocker arm for opening a valve that are pivotally supported on an engine block via respective common shafts, and a fixing angle between the two rocker arms. And a means for adjusting the mounting position of the retainer for receiving the rocking tip of the rocker arm with respect to the valve, so that the two adjusting means adjust the valve clearance appropriately.

However, such a conventional device has a problem in that the strength of the valve is reduced because a screw for screwing the retainer to the valve shaft of the valve is cut to adjust the mounting position of the retainer.

In addition, since the fixing angle adjusting means is provided between the two rocker arms, not only the adjusting operation becomes complicated, but also the inertia mass increases due to an increase in the number of parts.

An object of the present invention is to solve such a conventional problem.

(Means for Solving the Problems) In order to achieve the above object, according to the present invention, in a valve forced opening / closing device for an internal combustion engine, a cam for opening and a valve for closing are provided on a camshaft that is rotationally driven in synchronization with the engine. Each of the cams is formed, and a valve-opening rocker arm slidably contacting the valve-opening cam is provided,
The valve-opening rocker arm has a base end swingably supported with respect to the engine block and has a valve-closing rocker arm that slides on a distal end thereof with a valve-closing cam while sliding its distal end with a valve-closing cam. This rocker arm for valve closing is swingably connected with the rocker arm for valve opening halfway, and a retainer for slidingly contacting the tip of the rocker arm for valve closing is attached to the valve shaft of the valve. Adjusting means is provided.

(Function) Based on the above configuration, the valve-opening cam pushes down the valve-opening rocker arm with the rotation of the camshaft to lift the valve, and then the valve-closing cam pushes up the valve-closing rocker arm, whereby the retainer is raised. Pull the valve through.

The configuration in which the middle of the valve-closing rocker arm is swingably connected to the valve-opening rocker arm allows the relative positional relationship of each rocker arm, particularly the contact clearance with the valve head side, to be managed with high precision, while the engine block (cylinder head) 1) for each rocker arm for opening and closing, only one location is required, so that the structure of the valve mechanism and the engine block is simplified, and the valve clearance adjustment can be performed at one location, so that the adjustment work is also performed. It becomes very easy.

Further, since the structure for attaching the retainer to the valve is simplified, the strength of the valve is increased and the inertial mass is reduced.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a camshaft which is driven to rotate in synchronization with the engine. The camshaft 1 has one valve-opening cam 2 on the extension of the valve 4 and this valve-opening cam. Two valve closing cams 3 are formed so as to sandwich the cam 2.

Reference numeral 5 denotes a valve-opening rocker arm. The swinging tip of the rocker arm 5 is slidably contacted with the head of the valve 4, and an adjusting screw 6 is attached to the swinging base end of the rocker arm, and swings to a pivot 7 via the adjusting screw 6. Supported as possible.

The adjusting screw 6 is formed with a screw 6a to be screwed to the valve opening rocker arm 5, and by changing the screwing position with respect to the rocker arm 5, the swing center position of the valve opening rocker arm 5 is adjusted. The valve opening rocker arm 5 is tightened and fixed via a nut 8.

Adjusting screw 6 has spherical support for pivot 7
The pivot 7 is inserted through a hole 9 a formed in the cylinder head 9.

Reference numeral 15 denotes a valve closing rocker arm, and a shaft
It has two arm portions 15a that are swingably connected to the valve-opening rocker arm 5 via 16 and are in sliding contact with the respective valve-closing cams 3.

Reference numeral 17 denotes a retainer which is detachably attached to the valve shaft of the valve 4, and a rocker arm for closing the valve is provided on the lower surface of the retainer 17.
Slide the 15 tips.

An annular groove 4b is formed at the distal end of the valve shaft of the valve 4, and a ring-type collet 18 fitted in the annular groove 4b is provided. The retainer 17 is prevented from coming off via the collet 18.

With such a configuration, the operation will be described below.

As the camshaft 1 rotates, the valve-opening cam 2 pushes down the valve-opening rocker arm 5 to lift the valve 4, and then the valve-closing cam 3 moves the valve-closing rocker arm 15.
By pushing up the valve 4 through the retainer 17.
Pull up. Therefore, it is possible to abolish the conventionally provided valve spring, and to solve the problem such as surging.

The swing center of the valve opening rocker arm 5 is displaced by changing the screwing position of the valve opening rocker arm 5 with respect to the adjusting screw 6. Therefore, the clearance between the valve-opening rocker arm 5 and the cam 2 can be changed by adjusting the adjusting screw 6, and the valve clearance can be easily adjusted.

In addition, the gap between the valve closing rocker arm 15 and the cam 3 can be easily adjusted by changing the thickness of the retainer 17 which is detachably attached, and the retainer 17 can be attached using the collet 18. Attaching screws and the like for the retainer formed on the valve shaft can be eliminated to increase the strength of the valve 4 and reduce the number of components attached to the valve 4 to reduce the inertial mass.

Since the valve-closing rocker arm 15 is supported in the middle of the valve-opening rocker arm 5, the relative distance between the respective swinging tips, that is, the distance between the portions that come into contact with the head of the valve 4 via the retainer 17 can be precisely determined. The type of retainer 17 that can be retained and thus required for clearance adjustment is minimized. On the other hand, since only one pivot portion is required to support each combination of the rocker arms 5 and 15, the structure of the valve mechanism of the forced opening and closing type is relatively simple, so that the assembling work is also easy, Further, the shape and structure of the cylinder head 9 that tends to be complicated can be simplified.

Next, another embodiment shown in FIG.
In the multi-valve internal combustion engine provided with 4, the two valves 23, 24 are opened and closed by a pair of rocker arms 21, 22.

In this case, the valve opening rocker arm 21 has the valves 23, 24
The rocking tip portions 21a and 21b that are in sliding contact with the head of the valve closing rocker arm 22, respectively, are provided with rocking tip portions 22a and 22b that are in sliding contact with retainers 25 and 26 attached to the valves 23 and 24, respectively. It is formed.

Next, other embodiments shown in FIGS. 4 and 5, respectively,
A lash adjuster 32 is provided for pushing up the rocking base end of the valve opening rocker arm 31 by hydraulic pressure.

Reference numeral 33 denotes an oil gallery formed in the cylinder head 9, and pressurized oil is guided from an oil pump (not shown). The lash adjuster 32 has a spherical receiver 32a protruding by this hydraulic pressure, and the valve clearance of the valve opening rocker arm 31 is always adjusted to zero.

Next, other embodiments shown in FIGS. 6 and 7, respectively,
A spring that urges the valve closing rocker arm 22 in the valve closing direction.
With 35.

In this case, the valve-closing rocker arm 22 raises the valves 23 and 24 by the urging force of the spring 35 and presses the valves 23 and 24 against a valve seat (not shown), thereby improving the sealing performance of the combustion chamber.

(Effects of the Invention) As described above, according to the present invention, the rocker arm for valve opening has its base end swingably supported on the engine block, and its tip end slides on the head of the valve while closing. The valve rocker arm is pivotally connected at some point to the valve opening rocker arm, and a retainer for slidingly contacting the tip of the valve closing rocker arm is attached to the valve shaft of the valve, and a means for adjusting the rocking center position of the valve closing rocker arm is provided. Since it is provided, the adjustment work of the valve clearance becomes easy. A valve mechanism that can increase the strength of the valve, increase the output of the engine and improve the durability by reducing the number of parts and simplifying the structure, and can simplify and compact the structure as a valve mechanism and the engine block structure. There are many excellent effects such as easy assembling work.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, and FIG. 2 is a plan view of the same. FIG. 3 is a plan view showing another embodiment. FIG. 4 is a longitudinal sectional view showing another embodiment, and FIG. 5 is a plan view of the same. FIG. 6 is a longitudinal sectional view showing another embodiment, and FIG. 7 is a plan view of the same. 1 ... camshaft, 2 ... valve opening cam, 3 ... valve closing cam, 4 ... valve, 5 ... valve opening rocker arm, 6 ...
... Adjusting screw, 7 ... Pivot, 9 ... Cylinder head, 11 ... Spherical receiver, 15 ... Locker arm for valve closing, 16 ... Shaft, 17 ... Retainer, 18 ... Collet.

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Shigeru Kamagaya Nissan Motor Co., Ltd. 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture (56) References Microfilm (JP, U) photographing the contents of the specification and drawings attached to the application for 134503 (Japanese Utility Model Application No. 61-49006)

Claims (1)

(57) [Claims] 1. A valve opening cam and a valve closing cam are formed on a camshaft that is driven to rotate in synchronization with an engine, and a valve opening rocker arm is provided for sliding contact with the valve opening cam. The rocker arm has a base end swingably supported with respect to the engine block, and a distal end thereof is slidably contacted with the head of the valve, and a rocker arm for closing the valve is provided which is slidably contacted with a cam for closing the valve. The rocker arm is pivotally connected to the valve-opening rocker arm in the middle, and a retainer for slidingly contacting the tip of the valve-closing rocker arm is attached to the valve shaft of the valve. A valve forced opening / closing device for an internal combustion engine, the device being provided.