KR100290061B1 - Valve device of internal combustion engine - Google Patents

Abstract

[purpose]

In the three-valve SOHC structure consisting of two hop valves and one exhaust valve, a valve with low rotational limit (exhaust valve) at high speed rotation can be secured while ensuring proper valve mechanism layout and securing surface pressure and oil film characteristics of the pivot portion. The lift amount can be reduced, and the lift amount of the valve (intake valve) with a high rotational limit can be increased, and the difference in the rotational limit of both valves can be reduced to minimize the increase in the weight of the engine and the mechanical resistance.

[Configuration]

A three-valve SOHC structure consisting of two intake valves and one exhaust valve, the cylinder head lower surface (3) and the upper surface of the cylinder block are formed in parallel, and the axial direction of the cylinder bore and the respective intake valves (1), In the valve mechanism of an internal combustion engine in which the axial center directions and the like of the valve stems (5) and (6) are set equal to each other, the exhaust mechanism is provided between a single cam shaft 7 extending in the cylinder row direction and two intake ports. Intake pivots 12, 12 and one end of the intake pivot 12, the other end of the intake valve 1, and the rear side of the intake cam, which are respectively provided on both sides of the pivot and the cylinder inlet of one intake port. The intake rocker arm 13 and one end of the intake rocker arm 13, which are in close contact with each other (8), the other end of the exhaust rocker 25, and the other end of the exhaust rocker. An arm 26 or the like is provided and the intake valve 1 is in close contact with the intake pivot 12 provided on the opposite side of the cam rotation direction. A valve of an internal combustion engine, characterized in that it is driven by an existing rocker arm 13 and driven by an exhaust rocker arm 26 which is in close contact with an exhaust pivot 25 provided in the cam rotational direction. Instrument.

Description

Valve device of internal combustion engine

1 is a side view showing a valve device of the internal combustion engine of the present invention.

2 is a plan view of the cylinder head.

3 is a plan view of FIG.

4 is a cross-sectional view taken along the line C-C of FIG.

5 is a cross-sectional view taken along the line D-D of FIG.

6 is an explanatory diagram showing the lift amount of the intake valve.

7 is an explanatory diagram showing the lift amount of the exhaust valve;

8 is a cross-sectional view showing a conventional valve device.

9 is an enlarged view showing the gap between the pivot and the hemisphere.

10 is an explanatory diagram showing a variation of the valve lift amount.

* Explanation of symbols for main parts of the drawings

1: intake valve 2: exhaust valve

3: cylinder head 4: cylinder bore

5, 6: valve stem 7: camshaft

8: intake cam 9: exhaust cam

12: intake pivot 13: intake swing arm

25: exhaust pivot 26: exhaust swing arm

The present invention relates to, for example, a valve device of an internal combustion engine such as a diesel engine of a three-valve single overhead camshaft (SOHC) structure consisting of two intake valves and one exhaust valve.

Conventionally, as a valve device of an internal combustion engine, for example, as described in Japanese Patent Laid-Open No. 3-115710, a valve device having a five-valve structure composed of three intake valves and two exhaust valves, each swing arm on the intake side There is a device with staggered pivot positions.

In the valve device, the exhaust side has an exhaust swing arm having one end fixed to the exhaust pivot, the other end to the exhaust valve, and the rear side of the central portion to the exhaust cam. The valve lift amount of the exhaust valve is increased because it is configured to be driven by the exhaust swing arm which is in close contact with the exhaust pivot installed on the directional side (exhaust manifold side), and the rotation limit decreases due to the occurrence of valve jump. There was a problem.

Hereinafter, the above-described problem will be described in more detail with reference to FIGS. 8 to 10.

As shown in FIG. 8, at one end of the swing arm 84 with respect to the pivot 83 of the HLA 82 (abbreviation for hydraulic lash adjust, which stands for hydraulic lash adjust) provided on the cylinder head 81 side. While the hemispherical portion 85a at the lower end of the adjustment screw 85 attached is brought into close contact, the other end of the swing arm 84 is brought into close contact with the valve 86, and a roller attached to the middle part of the swing arm 84 The valve 86 is moved to the swing arm 84 described above, which is brought into close contact with the cam 89 of the cam shaft 88 and swings with the pivot 83 as a point by the rotation of the cam 89. Is configured to open and close the drive, as shown in FIG. 9 to secure an oil film between the hemispherical surface 83a on the groove and the hemisphere portion 85a at the lower end of the adjustment screw 85 as shown in FIG. Since the gap 90 is formed, when the rotational direction of the cam 89 is set in the direction of the arrow B in FIG. 8, the hemisphere 85a is in close contact with the gap 90. As shown in FIG. 10, the position (b) shown in FIG. 10 is pivoted as a pivot point, so that the valve lift amount is smaller than in the case where the pivot 83 is pivoted as the pivot point.

On the contrary, in the case where the rotational direction of the cam 89 is set in the direction of the arrow A in FIG. 8, the hemisphere 85a is in close contact with the gap 90 and moves to the left in FIG. 8, as shown in FIG. Since one point (a) is oscillated using the pivot point, the valve lift amount is increased as compared with the case where the pivot 83 is pivoted using the pivot point.

In particular, when the rotational direction of the cam 89 is set in the direction of the arrow A in FIG. 8, the valve lift amount of the valve 86 increases as described above, and when the valve lift amount increases in this way, the rotation occurs due to the occurrence of a valve jump. The limit is lowered.

Here, when the weights of the valves of the intake valve and the exhaust valve are compared, in general, the exhaust valve has a larger valve weight and a lower rotation limit. Therefore, when the exhaust valve and the valve device of the same valve are applied to the configuration of the rotation direction A of FIG. 8, there is a problem that the rotation limit is further deteriorated.

This is remarkable at high revolutions of the engine, and in order to solve this problem, when the spring limit is increased or the rotational limit is increased by improving the rigidity of the part, the engine weight increases and the mechanical resistance increases. There was this.

The present invention provides a valve with low rotational limit at high rotation while ensuring proper valve layout in a three-valve SOHC structure composed of two intake valves and one exhaust valve, and securing surface pressure and oil film characteristics of the pivot portion. It is possible to reduce the lift amount of the valve) and to increase the lift amount of the valve (intake valve) having a high rotational limit. Therefore, the difference in the rotational limit of both valves can be reduced to minimize the increase in engine weight and mechanical resistance. It is an object of the present invention to provide a valve device of an internal combustion engine.

The present invention has a three-valve SOHC structure consisting of two intake valves and one exhaust valve, wherein the lower surface of the cylinder head and the upper surface of the cylinder block are formed in parallel, and the axial direction of the cylinder bore and the valve stems of the respective intake / exhaust valves. A valve apparatus of an internal combustion engine in which the axial center direction is set to be the same, comprising: a single camshaft extending in the cylinder row direction, an exhaust pivot provided between two intake ports, and a cylinder row direction of one exhaust port; Intake pivots, one end of which is fitted to the intake pivot, the other end of which is in close contact with the intake valve, and the center side of the intake swing arm, one end of the exhaust pivot, the other end of the exhaust valve, the other end of the exhaust valve An intake swing arm in close contact with the exhaust cam, the intake swing arm in close contact with an intake pivot disposed in a direction opposite to the cam rotational direction. Drive, and wherein the valve system for an internal combustion engine configured to drive a swing arm for the exhaust to adhere to the exhaust pivot for placing the exhaust valve side cam rotational direction.

According to the present invention, the intake valve is driven by an intake swing arm in close contact with an intake pivot arranged on the side opposite to the cam rotation direction (exhaust manifold side), and the exhaust valve is rotated by the cam rotation direction (intake manifold side). Since it is configured to drive with an exhaust swing arm that is in close contact with the exhaust pivot disposed in the), a proper valve layout is secured in a three-valve SOHC structure consisting of two intake valves and one exhaust valve, and the surface pressure and oil film characteristics of the pivot portion can be improved. It can be secured.

Furthermore, when the cam rotates, one end of the intake swing arm comes into close contact with the pivot and moves toward the intake manifold to shorten the distance between the pivot point and the force point, thereby increasing the valve lift amount of the intake valve, thereby increasing the swing for exhaust. One end of the arm is in close contact with the pivot and moves toward the intake manifold, so that the distance between the pivot point and the force point becomes long, so that the valve lift amount of the exhaust valve is reduced.

Therefore, when the engine rotates at a high speed, the lift amount of the valve (exhaust valve) having a low rotational limit can be reduced and the lift amount of the valve (intake valve) with a high rotational limit can be increased, so that the difference between the rotation limits of both valves is reduced. This has the effect of minimizing the increase in engine weight and mechanical resistance.

In addition, since the axial direction of the valve stem and the axial direction of the cylinder bore are set to be the same, there is an effect that the intake valves and the exhaust valves arranged alternately with one cam shaft can be easily driven on the layout.

An embodiment of the present invention will be described in detail with reference to the drawings below.

The figure shows a valve device of an internal combustion engine, and in Figs. 1 to 5, the valve device of this diesel engine is a two intake valve having two intake valves 1 and 1 and one exhaust valve 2; The 3-valve SOHC structure has a single exhaust valve structure, and the lower surface of the cylinder head 3 and the upper surface of the cylinder block are formed in parallel, and the axial direction of the cylinder bore 4 and the above-described intake / exhaust valves 1, The shaft center directions of the valve stems 5 and 6 in 2) are set in the same manner.

In addition, as shown in FIG. 3, a single cam shaft 7 extending in the cylinder row direction is provided, which has two intake cams 8 and 8 and one exhaust cam per cylinder. (9) is integrally formed, and the exhaust cam 9 is provided at the center of the cylinder, and the intake cams 8 and 8 are provided on both sides of the exhaust cam 9. In addition, although the illustrated embodiment is a series multi-cylinder engine, only one cylinder is shown about a valve apparatus, and the illustration of another cylinder is abbreviate | omitted.

Furthermore, as shown in FIG. 2 and FIG. 4, HLA mounting portions 10 and 10 are integrally formed in the above-described cylinder head 3 corresponding to both of the cylinder row directions of one exhaust port. The hemispherical portion 15 of the lower end of the adjusting screw 14 attached to one end of the intake swing arm 13 is in close contact with the intake pivot 12 of the HLA 11 provided in the mounting portions 10 and 10. The roller 16 is attached to the middle portion of the intake swing arm 13 and the roller 16 is operated by the intake cam 8, whereby the valve contact portion 17 at the other end of the intake swing arm 13 is provided. The intake valve 1 is opened and closed via the valve stem 5 of the furnace intake valve 1.

The valve stem 5 described above is a stem disposed at a predetermined portion of the cylinder head 3 via a valve guide 18, and a spring is formed at an upper end of the valve stem 5 via a split collet 19. The retainer 20 is fitted, and the valve spring 22 is fitted between the spring seat 21 of the cylinder head 3 and the lower surface of the spring retainer 20 described above.

On the other hand, as shown in Figs. 2 and 5, an HLA mounting portion 23 is integrally formed in the above-described cylinder head 3 corresponding to two intake ports, and the HLA mounting portion 23 The hemispherical part 28 of the lower end of the adjustment screw 27 attached to one end of the swing arm 26 for exhaust is attached to the exhaust pivot 25 of the installed HLA 24, and this swing arm 26 for exhaust is attached. The roller 29 is provided in the middle portion of the valve, and the roller 29 is operated by the exhaust cam 9 so that the valve contact portion 30 at the other end of the swing arm 26 for exhaust is connected to the valve of the exhaust valve 2. The exhaust valve 2 is opened and closed via the stem 6.

Here, the valve stem 6 mentioned above is a stem provided in the predetermined part of the cylinder head 3 via the valve guide 31, The spring retainer 33 is provided in the upper end of this valve stem 6 via the split collet 32. ), The valve spring 35 is sandwiched between the spring seat 34 of the cylinder head 3 and the lower surface of the spring retainer 33 described above.

Since the rotation directions of the intake cam 8 and the exhaust cam 9 described above are the arrow directions (clockwise in Fig. 1) in Figs. 1, 4, and 5, as shown in Fig. 4 The intake valves 1 and 1 are configured to be driven by an intake swing arm 13 in close contact with the intake pivot 12 provided on the side opposite to the cam rotation direction (exhaust manifold side). As shown in the figure, one exhaust valve 2 is configured to be driven by an exhaust swing arm 26 in close contact with an exhaust pivot 25 provided on the cam rotational direction (intake manifold side).

As the illustrated embodiment is configured as described above, the following operation will be described.

Now, when the diesel engine is driven, the cam shaft 7 and the intake / exhaust cams 8 and 9 rotate in the directions of the arrows of Figs. 1, 4 and 5, and the rotation of the intake cam 8 described above. As a result, the hemispherical portion 15 of one end of the intake swing arm 13 closely moves to the intake manifold in close contact with the gap between the intake pivot 12 and the pivot point (point) and the force point as shown in FIG. Since the distance between them becomes short, the valve lift amount of the intake valve 1 becomes large.

In addition, due to the rotation of the exhaust cam 9 described above, the hemisphere 28 of one end of the swing arm 26 for exhaust moves in close contact with the gap between the exhaust pivot 25 and moves toward the intake manifold. As shown in Fig. 2, since the distance between the pivot point and the force point becomes long, the valve lift amount of the exhaust valve 2 becomes small.

Therefore, when the diesel engine rotates at a high speed, the lift amount of the valve having low rotational limit (exhaust valve 2) can be reduced and the lift amount of the valve having high rotational limit (intake valve 1) can be increased. The difference in the rotation limits of (1, 2) is made small, so that the increase in engine weight and mechanical resistance can be suppressed to a minimum.

In addition, the intake valves 1 and 1 described above are driven by an intake swing arm 13 in close contact with the intake pivot 12 provided on the side opposite to the cam rotational direction (the exhaust manifold side), and the exhaust valve (2) is configured to be driven by the exhaust swing arm 26 in close contact with the exhaust pivot 25 provided on the cam rotational direction side (intake manifold side) to pivot the swing arms 13, 26, 13; Since (12, 25, 12) are alternately provided as shown in FIG. 3, in a three-valve SOHC structure consisting of two intake valves and one exhaust valve, the surface pressure and oil film characteristics of the pivot portion while ensuring an appropriate valve layout are obtained. Can be secured.

Furthermore, since the axial center direction of the valve stems 5 and 6 and the axial center direction of the cylinder bore 4 are set to be the same, the intake valve 1 and the exhaust valve 2 which are alternately arranged with one cam shaft 7 are There is an effect that can be easily driven on the layout.

Claims (1)

It is a three-valve SOHC structure consisting of two intake valves and one exhaust valve. The lower surface of the cylinder head 3 and the upper surface of the cylinder block are formed in parallel, and the axial direction of the cylinder bore and the respective intake / exhaust valves 1, In the valve device of an internal combustion engine in which the axial center directions of the valve stems 5 and 6 of 2) are set to be the same, the exhaust device provided between a single cam shaft 7 extending in the cylinder row direction and two intake ports is provided. Pivots, intake pivots 12 and 12 provided at both sides of the cylinder row direction of one exhaust port, one end to the intake pivot 12, the other end to the intake valve 1, and the rear side of the inlet cam ( 8) an intake swing arm 13 which is in close contact with each other, an exhaust swing arm whose one end is in close contact with the exhaust pivot 25, the other end is in contact with the exhaust valve 2, and the center back is in close contact with the exhaust cam 9, respectively. And an intake pivot (1) provided with an intake valve (1) disposed opposite to the cam rotational direction. 2) is driven to the intake swing arm 13 in close contact and the exhaust valve 2 is driven to the exhaust swing arm 26 in close contact with the exhaust pivot 25 arranged in the cam rotational direction. A valve device of an internal combustion engine.