KR20040029441A - Whirl-stop device for rocker arm shaft in valve mechanism of internal combustion engine - Google Patents

Abstract

In the valve operation apparatus of the internal combustion engine which provided the two rocker arm shafts provided in the cylinder head, and rocked | supported by these with the rocker arm so that rocking was possible, the intake and exhaust valves interlocked. The rotation stop plate 42 is firmly tightened by the fastening bolt 43 to the cylinder head 3 between the arm shafts 32 and 33, and the first and second arm portions (of the rotation stop plate 42 are fixed). The engaging portions 42c and 42d formed on the front side in the fastening rotation direction a of 42a and 42b are hooked onto the caught portions 32a and 33a formed on the two rocker arm shafts 32 and 33, respectively. Fit. Thereby, rotation stop of the said two rocker arm shafts can be performed reliably.

Description

Rotation stop device of rocker arm shaft in valve actuation device of internal combustion engine {WHIRL-STOP DEVICE FOR ROCKER ARM SHAFT IN VALVE MECHANISM OF INTERNAL COMBUSTION ENGINE}

In general, in a valve actuating device of an internal combustion engine such as an SOHC type, two rocker arm shafts are arranged in parallel with a cylinder head of an engine main body in parallel, and these rocker arm shafts are rockers supported so as to be swingable respectively. The arm connects the intake and exhaust cams with the intake and exhaust valves, and by rotating the intake and exhaust cams, the intake and exhaust valves are opened and closed with predetermined timing, respectively (eg For example, see Japanese Laid-Open Patent Publication No. 2000-329002.

By the way, in such a valve movable apparatus, the two rocker arm shafts on the valve movable camshaft are supported by press-fitting or the like into the rocker arm shaft holes formed in the cylinder head, but the rotation stop means for the cylinder head is For example, as shown in FIG. 5, between two rocker arm shafts, the center part of a set plate is screwed to a cylinder head by a fastening bolt, and both ends of the left and right arm parts are provided. The rotation stop part symmetrically formed in the lower surface was made to contact the notch part of two rocker arm shafts, and rotation stop of two rocker arm shafts was performed.

By the way, in such a conventional rotation stop means of the rocker arm shaft, when the set plate is fastened by the fastening bolt, the set plate is rotated in the tightening direction, so that the position is located behind the firmly tightening rotation direction of the set plate. It is inevitable that a slight gap s is created between the notch of the rocker arm shaft and the rotation stop of the set plate, and the clearance of the rocker arm shaft caused by the gap s at the time of driving of the engine. There is a problem that a knocking sound is generated by electric movement.

So, as a solution to this problem,

(1) Install separate set stop plates for the two rocker arm shafts.

(2) Install an O-ring for stopping the rotation between each rocker arm shaft and the rocker arm shaft hole.

Although the above means may be considered, in the above ①, the number of parts is increased and the cost is not only high, but also because the extra space is occupied, the arrangement is difficult, and in the above ②, extra machining is performed on the rocker arm shaft. In addition to this, there are other problems such as an increase in the number of parts and an inconvenience in assembling work.

The present invention provides a valve actuating device for an internal combustion engine, wherein the intake and exhaust cams and two rocker arms that connect the intake and exhaust valves are swingably supported. A rotation stop device for a rocker arm shaft.

BRIEF DESCRIPTION OF THE DRAWINGS The longitudinal cross-sectional view of the principal part of the internal combustion engine provided with the rotation stop device of the rocker arm shaft in the valve movable apparatus of this invention.

2 is a cross-sectional view taken along line 2-2 of FIG.

3 is an enlarged sectional view taken along line 3-3 of FIG. 1;

4 is a cross-sectional view taken along line 4-4 of FIG. 1;

FIG. 5 is a cross-sectional view similar to FIG. 4 of a conventional valve operating device.

This invention is made | formed in view of such a situation, and an object of this invention is to provide the rotation stop device of the rocker arm shaft in the valve operation apparatus of the novel internal combustion engine which solved all the said problems.

In order to achieve the above object, the present invention provides a rocker in which two rocker arm shafts are arranged in parallel to a cylinder head of an engine main body, and a rocker for connecting the intake and exhaust cams with the intake and exhaust valves to these rocker arm shafts. In the valve operation apparatus of the internal combustion engine which supported the arm so that each rocking motion was possible, and the intake and exhaust cams were opened and closed at predetermined timing, respectively, by the rotation of the intake and exhaust cams,

In the middle portion of the two rocker arm shafts, the cylinder head is securely fastened by fastening the middle portion of the rotation stop plate that integrally extends the first arm portion and the second arm portion with a screw member, and stops the rotation stop. In the first and second arm portions of the plate, locking portions are provided on the front side in the rotational direction of tightening the screw member, respectively, and these locking portions are respectively formed in the caught portions formed in the opposite directions on the two rocker arm shafts. The rocker arm shafts are fitted so as to perform rotation stop of the rocker arm shafts. According to such a feature, the two rocker arm shafts are secured by the fastening of the rotation stop plate by the screw member to the cylinder head. Can stop the rotation stop accurately, and is due to the marginal transmission of the two rocker arm shaft at the time of engine operation The occurrence of noise can be prevented.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on the Example of this invention shown to an accompanying drawing.

First, with reference to FIGS. 1-4, one Example of this invention is described.

1 and 2, the engine main body E of the SOHC air-cooled four-cycle internal combustion engine includes a cylinder block 1 provided with a cylinder bore 2, and a cylinder block ( A crank case fixed on the deck face of 1), the cylinder head 3 having a combustion chamber 4 facing the cylinder bore 2, and a crank case fixed to the lower surface of the cylinder block 1. (crank case) 5, wherein the cylinder head 3 is provided with a valve movable device V described later, and the cylinder head 3 covers the valve movable device V on the cylinder head 3. A head cover 6 is mounted. The cylinder bore 2 is fitted with a sliding movement of a piston 8 freely through a cylinder sleeve 7, the piston 8 connecting a connecting rod 10. It is connected to a crank shaft, not shown.

Moreover, this internal combustion engine is a uni-flow type, The cylinder head 3 has an intake port 11 which opens to one side, and an exhaust port which opens to the other ( 12 is provided to face each other, and an intake machine In is connected to the intake port 11, and an exhaust system Ex is connected to the exhaust port 12, respectively. The intake port 11 is provided with the intake valve 13 which opens and closes the intake valve hole which communicates this with the combustion chamber 4, and the exhaust port 12 has an exhaust valve which communicates this with the combustion chamber 4. The exhaust valve 14 which opens and closes a hole is provided. Intake and exhaust valves 13, 14 are typically held in position to close the valves by valve springs 15, 16, respectively. In addition, before the ignition 17 is screwed to the wall surface surrounding the combustion chamber 4 of the cylinder head 3, the electrode faces the combustion chamber 4.

In the center part of the valve movable chamber formed on the cylinder head 3, the single valve movable camshaft 19 is rotatably supported through the bearings 23 and 24. As shown in FIG. The intake cam 20 and the exhaust cam 21 are integrally formed in the middle portion of the valve movable cam shaft 19 in the axial direction.

In one of the cylinder block 1 and the cylinder head 3 (left side of FIG. 2, FIG. 3), the timing transmission chamber 25 is formed across them, and in this timing transmission chamber 25, A timing driven gear 26 is fixed to one end of the valve movable cam shaft 19 (FIGS. 2 and 3 left ends), and the gear 26 has an endless shape. Interlocked with a timing drive gear fixed to a crankshaft (not shown) via a timing chain 27 of the crankshaft, and typically, rotation of the crankshaft is transmitted to the valve actuating camshaft with a reduction ratio of 1/2. have. The bolt 28 penetrating the side wall of the cylinder head 3 is inserted into the hollow valve movable cam shaft 19, and timing transmission is carried out to the edge part of this bolt 28. As shown in FIG. The cover 29 which covers the opening part of the cylinder head 3 side of the seal 25 is attached with a screw.

The cylinder head 3 has two rocker arm shaft holes 30 and 31 on the intake side and the exhaust side in parallel with the valve movable cam shaft 19 on the left and right sides of the valve movable cam shaft 19. It is drilled and installed. These rocker arm shaft holes 30 and 31 are formed as holes blocked by one of the openings on the timing transmission chamber 25 side as shown in FIG. 3. In this embodiment, the rocker arm shaft holes on the exhaust side are formed. The 31 is formed longer than the rocker arm shaft hole 30 on the intake side. Two rocker arm shaft holes 30 and 31 are press-fitted into two rocker arm shafts 32 and 33 from the opening side, that is, the intake side and the exhaust side. In these two rocker arm shafts 32 and 33, the intermediate portions of the rocker arms 34 and 35 on the intake side and the exhaust side are freely supported by swinging the positions in their axial directions. The outer end of the intake side rocker arm 34 is connected to the upper end of the intake valve 13 via a tappet 37, and the inner end thereof is supported therein by the shaft. Is connected to the cam face of the intake cam 20 of the valve movable camshaft 19 via a roller 39, while the outer end of the exhaust rocker arm 35 is tappet 38. Is connected to the upper end of the exhaust valve 14, and the inner end thereof is connected to the cam surface of the exhaust cam 21 of the valve movable cam shaft 19 through a roller 40 supported therein by the shaft. . Therefore, according to the rotation of the valve movable cam shaft 19, the rocker arms 34 and 35 on the intake side and the exhaust side swing around the rocker arm shafts 32 and 33, respectively, and the valve springs 15 and 16 ), The intake valve 13 and the exhaust valve 14 are opened and closed at a predetermined timing, and the internal combustion engine is operated.

However, the two rocker arm shafts 32 and 33 on the intake side and the exhaust side do not allow the inside of the hole of the rocker arm shafts 30 and 31 to be relaxed even by the operation of the valve actuating device V. Rotation stop means is provided. That is, as shown to FIG. 3, FIG. 4, the center part of the rotation stop plate 42 is fastened by the screw member, ie, the fastening bolt 43, just above this valve movable camshaft 19 in parallel. It is fixed. The rotation stop plate 42 integrally includes a first arm portion 42a extending toward the intake side rocker arm shaft 32 and a second arm portion 42b extending toward the exhaust side rocker arm shaft 33. The lower surface thereof is formed with an arc concave surface substantially concentric with the valve movable camshaft 19. On the first and second arm portions 42a and 42b of the rotation stop plate 42, the two end portions are provided on the front end side in the rotation direction of the fastening bolt 43 of the rotation stop plate 42. The rocker arm shafts 32 and 33 are formed with flat locking portions 42c and 42d that can be engaged with the caught portions 32a and 33a described later, and as shown in FIG. 4, the first arm portion 42a. ) And the locking portion 42c of the second arm portion 42b is upwardly formed on the end side surface thereof. In addition, at one end corresponding to the rotation stop plate 42 of the two rocker arm shafts 32 and 33, there are formed caught portions 32a and 33a notched in a semicircle shape, respectively. As shown in FIG. 4, when the rotation stop plate 42 is rotated in the tightening direction (arrow a in FIG. 4) to fasten and fix the rotation stop plate 42 to the cylinder head 3 with the fastening bolt 43. The rotation stop plate 42 is also rotated in the same direction (arrow b direction in FIG. 4), and the locking portions 42c and 42d at both ends of the rotation stop plate 42 are two rocker arm shafts 32 and 32. Is engaged without gaps in the caught portions 32a and 33a. As described above, the two rocker arm shafts 32 and 33 are reliably stopped by rotation of the screw member of the rotation stop plate 42, that is, the fastening bolt 43, so that the engine is in operation. Therefore, the occurrence of a knocking sound due to the marginal rolling of the two rocker arm shafts 32 and 33 can be prevented in advance.

As mentioned above, although one Example of this invention was described, this invention is not limited to the Example, A various Example is possible within the scope of this invention. For example, in the said embodiment, although the case where the rotation stop device of the rocker arm shaft which concerns on this invention was implemented in SOHC type internal combustion engine was demonstrated, this can be implemented also in another internal combustion engine provided with two rocker arm shafts. Of course.

Claims (1)

Two rocker arm shafts 32, 33 are installed in parallel on the cylinder head 3 of the engine body E, and these rocker arm shafts 32, 33 are mounted in parallel. , The intake and exhaust cams 21 and 22, and the rocker arms 34 and 35 connecting the intake and exhaust valves 13 and 14 so as to allow oscillation, respectively, and the intake and exhaust cams 21 and 22. In the valve actuating device of an internal combustion engine, the intake and exhaust valves 13 and 14 are opened and closed at predetermined timings, respectively, through the rocker arms 34 and 35. In the intermediate portions of the two rocker arm shafts 32 and 33, the cylinder head 3 has a rotation stop plate 42 in which the first arm portion 42a and the second arm portion 42b are integrally extended. The middle part is tightened and fixed firmly with the screw member 43, and the first and second arm portions 42a and 42b of the rotation stop plate 42 are fastened to the front side of the screw rotation direction of the screw member 43. 42c and 42d are provided, respectively, and these locking parts 42c and 42d are respectively engaged with the caught parts 32a and 33a formed in the said rocker arm shaft 32 and 33 in the opposite direction, respectively. The rotation stop device of the rocker arm shaft in the valve movable device of an internal combustion engine characterized by performing rotation stop of those rocker arm shafts (32, 33).