JPH11153006A - Valve system of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve abrasion resistance property, reduce processing cost and secure enough lubrication at a sliding part. SOLUTION: This valve system comprises a swing arm 5, on end of which is supported by a pivot part 4 and the other end part of which is engaged with a top end of a valve shaft 3a, and a cam roller 7 which is provided in the middle of the swing arm 5. A steel ball 11 is fixed to combine with one end part of the swing arm 5 made of sheet metal, a bearing member 12 which has a spherical recessed part 13 rotatably supporting the steel ball 11 is installed to a cylinder head 1, and a bearing collar 15 which stores up lube oil is provided on a circumference of the spherical recessed part 13 of the bearing member 12 to be projected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve mechanism for an internal combustion engine, and more particularly to an improvement in a pivot portion of a swing arm in a valve mechanism of an overhead camshaft type and a swing arm system.

[0002]

2. Description of the Related Art An overhead camshaft type valve operating mechanism disposed on a cylinder head of an internal combustion engine, in particular, the other end of a swing arm having one end supported by a pivot portion is engaged with the tip of a valve shaft. A valve mechanism of a swing arm type in which a cam engaging portion is provided at an intermediate portion is well known as disclosed in, for example, Japanese Utility Model Laid-Open No. 1-99905.

An example will be described with reference to FIG. 3. Referring to FIG. 3, a valve operating mechanism 35 for opening and closing an intake valve 34 and an exhaust valve 35 for opening and closing an intake port 32 and an exhaust port 33 formed in a cylinder head 31, respectively. The pressing portion 38 at the other end of the swing arm 37, one end of which is supported by the pivot portion 36, is engaged with the valve shaft tips 34 a, 35 a of the valves 34, 35. A cam roller 39 whose surface is engaged is provided, and the swing arm 37 swings with the rotation of the cam 40 so that the valves 34 and 35 open and close.

[0004] The pivot portion 36 has a support bowl portion 41 having a downwardly concave spherical surface 42 formed at one end of a swing arm 37.
And a spherical portion 44 is formed at the upper end, and a screw portion 45 is formed at the lower portion.
Is formed by screwing a pivot member 43 formed with a screw to a receiving seat 46 provided on the cylinder head 31. Also,
A lubricating oil hole 46 for supplying lubricating oil to a sliding portion of the spherical concave surface 42 and the spherical portion 44 is formed at the top of the bearing bowl 41 of the swing arm 37.

[0005]

However, in the configuration of the swing arm 37 and the pivot portion 36, the support bowl portion 41 at one end of the swing arm serving as a sliding portion.
Spherical surface 42 and spherical portion 44 at the upper end of pivot member 43
Are required to be processed into highly accurate spherical surfaces, and their hardness must be increased in order to ensure wear resistance, resulting in an increase in processing cost. Further, a material which is easy to manufacture by forging, sheet metal, casting or the like is selected for the swing arm 37, but there is a problem that the material selection range of the swing arm 37 is narrowed in order to secure the processing accuracy and hardness.

It is also conceivable to form an internal thread at one end of the swing arm 37 and attach an adjusting screw provided with a spherical portion at the tip. In this case, the selection range of the material of the swing arm is widened structurally. Although it is possible to use a low-cost material made of sheet metal, the processing cost is high in order to secure the processing accuracy and hardness of the spherical sliding portion, and it is difficult to process the internal thread when the swing arm 37 is made of sheet metal. There is a problem that is.

Further, only a small amount of lubricating oil can be supplied from a small lubricating oil hole 46 drilled at the top of the bearing bowl 41, and one end of the swing arm 37 swings at high speed and is made of sheet metal. In such a case, a lubricating oil reservoir cannot be provided on the top of the bearing bowl portion 41, so that the sliding portion cannot be sufficiently lubricated, and there is a problem that wear is likely to occur.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides an internal combustion engine that has high wear resistance, can reduce machining costs, can widen the range of material selection for a swing arm, and can sufficiently ensure lubrication of a sliding portion. It is an object of the present invention to provide a valve operating mechanism.

[0009]

According to a valve mechanism for an internal combustion engine of the present invention, the other end of a swing arm having one end supported by a pivot portion is engaged with a tip of a valve shaft, and a cam is provided at an intermediate portion of the swing arm. In a valve mechanism of an internal combustion engine provided with an engaging portion, a pivot portion, a steel ball is integrally fixed to one end of a swing arm, and a receiving member having a spherical concave portion rotatably supporting the steel ball is attached to a cylinder head. Since the spherical portion can be formed with steel balls at low cost, a pivot portion having high wear resistance can be obtained at low cost.

Further, when a steel ball is welded to a swing arm made of sheet metal, the swing arm can be constituted by a sheet metal of inexpensive material, and the cost can be further reduced.

Further, when a receiving collar projects from the outer periphery of the spherical concave portion of the receiving member, lubricating oil accumulates on the receiving flange, and the lubricating oil is supplied to the sliding portion between the spherical concave portion and the steel ball, so that lubrication is sufficiently provided. As a result, wear can be prevented.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the valve train of an internal combustion engine according to the present invention will be described below with reference to FIGS.

In FIG. 1, reference numeral 1 denotes a cylinder head, and 2 denotes a valve mechanism for opening and closing a valve 3 such as an intake valve or an exhaust valve for opening and closing an intake port and an exhaust port formed in the cylinder head 1. The valve train 2 includes a swing arm 5 and a cam 8.
It consists of. The swing arm 5 has one end 5 a supported by the pivot portion 4, the pressing portion 6 at the other end 5 b is engaged with the valve shaft tip 3 a of each valve 3, and the swing arm 5 has an intermediate portion. A cam roller 7 with which the peripheral surface of the cam 8 is engaged is provided.

As shown in FIGS. 1 and 2, the pivot portion 4 has a downward spherical concave portion 1 at one end of a swing arm 5.
0 is formed, and a steel ball 1 is
1 is fitted and fixed integrally by resistance welding, and a receiving member 12 having a spherical concave portion 13 for rotatably supporting the steel ball 11 is attached to a receiving seat 1a provided on the cylinder head 1. Have been. Receiving member 12
In the lower part, a screw portion 14 for screw fixing to a screw hole 1b formed in the receiving seat 1a is formed.

The swing arm 5 is, as shown in FIG.
The cross-sectional shape having an upper wall 16 and both side walls 17 hanging down from both sides thereof is made of sheet metal which is press-formed in a substantially U-shape with a downward opening, and the side wall 17 has a low height at both ends and a high height at an intermediate portion. Is formed high. The support bowl 9 is press-molded on an upper wall 16 at one end 5 a of the swing arm 5. The pressing portion 6 is formed by bending the upper wall 16 at the other end portion 5b of the swing arm 5 so as to project slightly downward, and the swing arm 5 swings the valve shaft tip 3a smoothly. It is configured to press.

An opening 18 is formed in the middle part of the swing arm 5 by cutting off the upper wall 16 over the entire width. The cam roller 7 is arranged between the side walls 17 so that the upper end protrudes from the opening 18. A support shaft 20 for rotatably supporting the cam roller 7 is inserted into a shaft hole 19 formed so as to penetrate both side walls 17. The support shaft 20 is formed of a hollow shaft, and both ends thereof are fixed to the side wall 17 by swaging 21. A bearing metal 22 is fitted and fixed to the inner periphery of the cam roller 7.

In the above configuration, the cam roller 7 is pushed down at the rotational position where the large diameter portion of the cam 8 is engaged with the cam roller 7, and the swing arm 5 swings downward with the pivot portion 4 as a fulcrum. When the tip 3a of the valve shaft is depressed, the respective valves 3 are opened, and the swing arm 5 swings upward with the pivot portion 4 as a fulcrum at the rotational position where the small diameter portion of the cam 8 engages with the cam roller 7. A spring 23 for urging the valve 3 in the upward direction,
When the cam 3 rotates, the valve 3 opens and closes as the cam 8 rotates.

As described above, since the swing arm 5 swings up and down with the pivot portion 4 as a fulcrum every time the valve 3 is opened and closed, the pivot portion 4 is easily worn, but in the present embodiment, the sphericity is high. Since the steel ball 11 having small surface roughness, high hardness, high wear resistance, and which can be obtained extremely inexpensively is welded to one end of the swing arm 5, the spherical portion of the pivot portion 4 is formed. A spherical portion having high processing accuracy and high hardness can be easily and inexpensively formed, and a pivot portion 4 having high wear resistance can be obtained at low cost. Further, since the steel ball 11 is welded to the swing arm 5 made of sheet metal, the swing arm 5 can be made of sheet metal of inexpensive material, and the cost can be further reduced.

Further, since the receiving flange 15 is provided on the outer periphery of the spherical concave portion 13 of the receiving member 12, the lubricating oil scattered in the cam chamber of the cylinder head 1 easily accumulates on the receiving flange 15. Since the lubricating oil is smoothly supplied to the sliding portion between the spherical concave portion 13 and the steel ball 11, lubrication is sufficiently ensured and wear can be prevented.

[0020]

According to the valve train of an internal combustion engine of the present invention,
As described above, the pivot portion is formed by integrally fixing the steel ball to one end of the swing arm and attaching the receiving member having the spherical concave portion for rotatably supporting the steel ball to the cylinder head. A spherical portion can be formed at low cost and a pivot portion having high wear resistance can be obtained at low cost.

Further, when a steel ball is welded to a swing arm made of sheet metal, the swing arm can be formed of a sheet metal of inexpensive material, and the cost can be further reduced.

Further, when a receiving flange is provided on the outer periphery of the spherical concave portion of the receiving member, lubricating oil accumulates on the receiving flange, and the lubricating oil is supplied to the sliding portion between the spherical concave portion and the steel ball, so that lubrication is sufficiently provided. As a result, wear can be prevented.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view of a cylinder head provided with a valve train of an internal combustion engine according to an embodiment of the present invention.

2A and 2B show a configuration of a swing arm according to the embodiment, wherein FIG. 2A is a plan view, FIG. 2B is a cross-sectional view taken along the line AA of FIG. 2A, FIG. 2C is a front view, and FIG. It is an BB sectional view taken on the line BB of a).

FIG. 3 is a longitudinal sectional view of a conventional cylinder head provided with a valve mechanism for an internal combustion engine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Valve train mechanism 3a Valve shaft tip 4 Pivot part 5 Swing arm 7 Cam roller 11 Steel ball 12 Receiving member 13 Spherical recess 15 Receiving flange

Claims (3)

[Claims] In a valve operating mechanism for an internal combustion engine, the other end of a swing arm having one end supported by a pivot portion is engaged with a tip of a valve shaft, and a cam engaging portion is provided at an intermediate portion of the swing arm. A valve mechanism for an internal combustion engine, characterized in that a steel ball is integrally fixed to one end of a swing arm, and a receiving member having a spherical concave portion for rotatably supporting the steel ball is attached to a cylinder head. 2. The valve operating mechanism for an internal combustion engine according to claim 1, wherein a steel ball is welded to a swing arm made of sheet metal. 3. The valve mechanism of an internal combustion engine according to claim 1, wherein a receiving flange is provided on an outer periphery of the spherical concave portion of the receiving member.