KR960013346B1 - Valve opening & closing instrument - Google Patents

Abstract

The mechanism's major part is rocker arm(210) contacted with a cam(110) at one end and contacted with the top of an exhaust valve(3) at another end, etc. The operating process comprises: a cam shaft(100) turning clockwise; the convex part of the cam(110) for pushing the upper part of an intake valve(2), and opening the valve (the begining of the intake stroke); the convex part of the cam(110) passing over the upper part of the intake valve(2) and the intake valve(2) closing(the progressing of the compression and combustion stroke); the convex part of the cam(110) for getting contacted with one end of the rocker arm(210), and opening the exhaust valve(3) (the begining of the exhaust stroke). If using adjuster(300) inserted between the cam(110) and the top of the intake valve(2) at one end and hung up on the rocker arm shaft(200) at another end, the contact of the cam(110) and the intake valve(2) gets close.

Description

Valve opening and closing mechanism

1 and 2 are cross-sectional views showing a conventional overhead camshaft valve mechanism.

3 is a cross-sectional view of an operating state according to the first embodiment of the present invention.

4 is a cross-sectional view of an operating state according to a second embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

1 cylinder head 2 intake valve

3: exhaust valve 100: camshaft

110: cam 200: rocker arm shaft

210: rocker arm 300: adjuster

The present invention relates to a valve opening and closing mechanism of a four-cycle engine, and more particularly, to an overhead camshaft type valve opening and closing mechanism.

The valve opening and closing mechanism functions to open and close the intake valves and exhaust valves arranged in the combustion chamber of the cylinder, and according to the configuration and the installation position thereof, the side valve type, the overhead head type, It is classified as Over Head Vale type.

In the double overhead camshaft type, a single overhead camshaft type which operates the intake valve 2 and the exhaust valve 3 in the cylinder head 1 with one camshaft 10a as shown in FIG. (Singl Over Head Camshaft type) and the double overhead camshaft for operating the intake valve (2) and exhaust valve (3) with the cylinder head (1) with two camshafts (10a) as shown in FIG. There is a formula (Double Over Head Camshaft type).

Such an overhead camshaft type has a low inertia force in the reciprocating portion of the valve, so that the acceleration of the valve can be increased. Therefore, it is possible to open and close the valve at a high speed, thereby improving the high speed performance and increasing the engine speed quickly at low speed and high speed.

In the case of a single overhead camshaft type, one camshaft 10a is mounted on the cylinder head 1, and the cam 10a moves directly to the rocker arm 21 which is condensed on the rocker arm shaft 20. In addition, the rocker arm 21 is required as many as the number of the intake valve 2 and the exhaust valve 3, so that the structure of the cylinder head 1 is complicated.

In the case of the double overhead chem shaft type, two cam shafts 10b are installed on the cylinder head 1 so that each chem 10b 'directly moves the intake valve 2 and the exhaust valve 3. As an advantage, the rocker arm shaft 20 and the rocker arm 21 are not required, and an ideal combustion chamber can be designed in terms of performance, but disadvantages in terms of design and manufacturing difficulty and price of the valve opening and closing mechanism are required. There is this.

The present invention consists of one cam shaft and one rocker arm shaft, which is installed on the cylinder head and operated by one cam and rocker arm for one set of intake and exhaust valves, simplifying the design, design, and manufacturing of the cylinder head. The purpose is to ensure the flexibility of the award.

In order to achieve the object of the present invention by forming a series of cams, the cam is coupled to one cam shaft and a series of rocker arms installed on the cylinder head so as to be external to the upper end of the intake valve, one end of the rocker arm is It is proposed to consist of one rocker arm shaft mounted on the cylinder head in contact with the cam and the other end in contact with the upper end of the exhaust valve.

Hereinafter, two preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a cross-sectional view of an operating state of the valve opening and closing mechanism according to the first embodiment of the present invention.

As shown in FIG. 3, the present invention installs one camshaft 100 on the cylinder head 1 such that the upper end of the intake valve 2 and the cam 110 are circumscribed. In addition, one end of the rocker arm 210 is circumscribed to the cam 110, and the other end is provided with one rocker arm shaft 200 to the cylinder head 1 so as to contact the upper end of the exhaust valve (3).

Since the present invention is applied to a four cycle engine, the opening and closing times and heights of the intake valve 2 and the exhaust valve 3 should be appropriate according to the intake, compression, combustion, and exhaust stroke. And the shape of the rocker arm 210 should be appropriately designed. In addition, by properly setting the angles of the intake valve 2 and the rocker arm 210 which are external to the cam 110 with respect to the center point of the cam shaft 100 at the time of installation, the intake valve 2 is correctly opened and the exhaust stroke To allow the exhaust valve (3) to open correctly.

The present invention installed as described above has a structure in which a set of intake valves 2 and exhaust valves 3 are operated by one cam 110.

According to the present invention, as shown in FIG. 3, when the block surface of the cam 110 contacts the upper end of the intake valve 2, the intake valve 2 is opened and the outer diameter of the cam 110 is increased. The rocker arm 120, one end of which is engaged, is not rotated and the exhaust valve 3 is closed. In this case, it corresponds to the intake stroke.

In this state, the cam shaft 100 rotates in a clockwise direction so that the convex surface of the cam 110 starts to deviate from the upper surface of the intake valve 2 and the intake valve 2 is closed so that compression and combustion stroke proceed. do. Then, when the convex surface of the cam 110 comes into contact with one end of the rocker arm 210, the rocker arm 210 rotates counterclockwise around the rocker arm shaft 200, and the exhaust valve 3 is opened. do. In this case, it corresponds to the exhaust stroke.

In this way, one cam 110 in the cam shaft 100 can control the opening and closing timing of the pair of intake valves 2 and the exhaust valves 3. In addition, by designing the curved surface shape of the cam 110 and the lever ratio of the rocker arm 210 can be adjusted appropriately the opening and closing clearance of the intake valve (2) and exhaust valve (3).

Therefore, the intake valve 2 and the exhaust valve 3 can be operated simultaneously with one camshaft 100 having a series of cams 110 and one rocker arm 200 having a series of rocker arms 210. do.

4 is a cross-sectional view of an operating state of the valve opening and closing mechanism according to the second embodiment of the present invention.

The second embodiment includes the configuration of the present invention illustrated in the first embodiment, one end is interposed to be in contact with the upper end of the cam 110 and the intake valve 2 and the other end is the rocker arm shaft 200 It is further provided with an adjuster (adjiuster: 300) connected to be rotated. Therefore, the cam 110 can be spaced apart from the intake valve 2 so that the cam shaft 100 can be installed adjacent to the intake valve 2, so that it is designed by adding an adjuster 300 when it is difficult. Be able to exercise the flexibility of.

The adjuster 300 according to the present invention forms a head 310 at one end to remove the play between the cam 110 and the intake valve 2 and the other end to be pivotally connected to the rocker arm shaft 200. The connection part 320 is formed in the. The head 310 is preferably designed in size and shape so that the line contact with the upper end of the cam 110 and the intake valve (2), the connecting portion 320 is formed in a hook shape to the rocker arm shaft (200) It is desirable to be able to spread over.

The adjuster 300 having such a structure rotates the connection part 320 to the rotation center while the cam 310 contacts the head 310 as the cam shaft 200 rotates. As a result, the cam 110 indirectly constructs the intake valve 2 through the adjuster 300. Other operation relations are the same as described in the first embodiment and thus are omitted.

As described above, the present invention basically consists of a camshaft with a series of cams and a rocker arm shaft with a series of rock levers so that the intake valve and the exhaust valve can be controlled simultaneously. When installing, the structure of the cylinder head can be simplified to reduce the manufacturing cost, and the structure of the parts can be simplified to provide flexibility in design and manufacturing.

Claims (2)

A series of cams 110 are formed, the one camshaft 100 installed on the cylinder head 1 and the series of rocker arms 210 coupled to the upper end of the intake valve 110 and the One end of the rocker arm 210 is externally formed on the cam 110 and the other end of the rocker arm shaft 200 is installed on the cylinder head 1 to be in contact with the upper end of the exhaust valve 2. Valve opening and closing mechanism. According to claim 1, one end is interposed in contact with the upper end of the cam 110 and the intake valve (2) and the other end is connected to the locker arm shaft (200) adjuster (adjuster: 300) Valve opening and closing mechanism characterized in that provided.