JPS6318117A - Valve system for internal combustion engine - Google Patents

Abstract

PURPOSE:To lighten a rocker arm, by forming a downward recessed columnar surface at an intermediate portion of the rocker arm which columnar surface has an axis perpendicular to a rocking direction of the rocker arm and serves as a fulcrum portion, and providing a supporting member rockably supporting the fulcrum portion. CONSTITUTION:In an engine having an exhaust value 17 adapted to be opened and closed directly by an exhaust value cam and having an intake valve 15 adapted to be opened and closed through a rocker arm 45 by an intake valve cam be the rotation of a cam shaft 21, the rocker arm 45 is formed at its substantially longitudinal center with a fulcrum portion 45A having a downward recessed columnar surface 51 which has an axis perpendicular to a rocking direction of the rocker arm 45. The rocker arm 45 is rockably supported by a rocker arm supporting member 47 mounted to a holder 49 to be fixed to a cylinder head 5. The supporting member 47 is constituted of a threaded portion 47A and an engagement portion 47B formed at the lower end of the threaded portion 47A and adapted to engage the fulcrum portion 45A.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a valve train for an internal combustion engine that can reduce the weight of a rocker arm.

(Problems to be Solved by the Prior Art and the Invention) Two locations spaced apart from the fulcrum in the longitudinal direction engage with the camshaft side and the top of the intake or exhaust valve, respectively, and the camshaft In a valve train for an internal combustion engine, a rocker arm that swings about the fulcrum part and opens and closes the valve is disposed on the cylinder head. In order to improve followability, it is desirable to reduce the weight of the rocker arm as much as possible.

However, in the conventional valve train,
As disclosed in Publication No. 09, an adjustment screw is attached to the rocker arm to adjust the gap between the valve top and the low 7 arm, that is, the valve clearance, and the weight of the rocker arm cannot be reduced accordingly. was there.

The present invention was devised to solve the above-mentioned problems, and an object of the present invention is to provide a valve train for an internal combustion engine that can reduce the weight of the rocker arm by removing the adjustment screw from the rocker arm. It is in.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides the rocker arm (
A cylinder head (5) in which the fulcrum part (45A) of the cylinder head (45) is open above the cylinder head (5), and the axis (51A) extends in a direction perpendicular to the swinging direction of the lower two arm (45). a downwardly concave cylindrical surface (51);
Side surfaces (53), (53) formed on both sides of the rocker arm (45) in the direction perpendicular to the rocking direction of the rocker arm (45) in 1).
), a rocker arm support member (47) is provided vertically adjustable from the upper side of the cylinder head (5), and the cylindrical surface (51) and the cylindrical surface ( an engaging portion (47B) having engaging surfaces (75), (7?), and (77) that can be freely engaged with side surfaces (53), (53) on both sides of the rocker arm support member (51), respectively; (47) Engagement part (47B)
is engaged with the fulcrum part (45A) of the rocker arm (45) to support the rocker arm (45) - (Function) Engagement of the fulcrum part (45A) of the rocker arm (45) and the rocker arm support member (47) By engaging with the part (47B), the rocker arm (45) is swung in a certain direction and the valve (1
5) The valve clearance is adjusted by vertically adjusting the rocker arm support member (47). Therefore, the weight of the rocker arm (45) can be reduced by removing the conventional adjustment screw from the rocker arm (45).

(Example) Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, to explain the first embodiment, Fig. 1 is a cross-sectional side view of the main part of the cylinder head, Fig. 2 is a plan view of the same,
FIG. 3 shows a view taken along arrow m in FIG.

(1) is a water-cooled 4-cylinder engine, (3) is a cylinder block, (5) is a cylinder head, and cylinder block (
3) has four cylinder pores (7) arranged in a row, a piston (8) is fitted in the cylinder pore (7), and a spark is placed in the combustion chamber (11) on the lower surface of the cylinder head (5). Plug (13), two intake valves (15), (1
5) and two exhaust valves (17), (17).

One cam shirt (21) is disposed on one side above the cylinder pore (7) on the cylinder head (5).

The exhaust valves (17), (17) are vertically arranged between the combustion chamber (11) and the camshaft (21), with the exhaust valves (17) being offset to one side from the center of the cylinder pore.

The exhaust valve (17) is arranged so that the exhaust port (31) is biased in the closing direction by a valve guide (23), a spring retainer (25), a valve spring (27), and a valve spring seat (28). Engage the tappet (33) disposed on the top of the valve (17) with the exhaust valve cam part (21A) of the cam shirt (21),
The exhaust valves (17), (17) are directly driven by the rotation of the exhaust boat (31), (31) to open and close the exhaust boats (31), (31).

The intake valves (15) and (15) are arranged vertically and are offset from the center of the cylinder pore to the other side.

The intake valves (15) and (15) each have a valve guide (
35), a spring retainer (37), a valve spring (38), and a valve spring seam (41) bias the intake port (43) in the closing direction. (43)
, (43) are opened and closed by swinging the two rocker arms (45), (45) engaged with the cam shirt (21).

The rocker arm (45) is a rocker arm support member (45) disposed between the camshaft (21) and the top of the intake valve (15).
The rocker arm support member (47,) is supported by a holder (48).

The rocker arm (45) has a fulcrum (45A) formed approximately at the center in the longitudinal direction, and a slipper surface (45) extending from the fulcrum (45A) toward the cam shirt (21) side.
B) is the intake valve cam part (21B) of the camshaft (21).
) and the arm part (45G) that engages with the fulcrum part (45A).
The slipper surface (45) at the tip extends from the side toward the intake valve (15).
11) engages with the top of the intake valve (15).
E).

As shown in FIG. 4, the fulcrum portion (45A) has a cylindrical surface (open upwardly) and concave downwardly (51A) extending in a direction perpendicular to the rocking direction of the rocker arm (45).
51) and a rocker arm (45) on the cylindrical surface (51).
) are formed on both sides in a direction perpendicular to the swinging direction of (53) and (53), respectively.

The holder (49) is arranged on the cylinder head (5) substantially above the center of the cylinder pore (7), and has a cylindrical part (57) through which a spark plug insertion hole (55) is penetrated.
, a bearing part (59) having a semicircular bearing surface extending from each cylinder part (57) toward the camshaft (21) and supporting the journal part of the camshaft (21), and an adjacent cylinder part (
57) and (57).

The plug insertion hole (55) is formed continuously with the spark plug insertion hole (B3) of the cylinder head (5), which is formed toward approximately the center of the combustion chamber (11).

The bridge portion (61) is formed to extend from the upper surface of the cylinder head (5) while maintaining an appropriate height, and the bridge portion (81) is provided with a rocker arm (45) as shown in FIG.

Holes (Ei5) and (65) are formed through the hole (Ei5) corresponding to the hole (45), and a groove (87) is formed in the inner peripheral surface of the hole (65) along the direction of the hole (65).

The holder (49) is installed by attaching both sides of the bearing part (53) and the outer part of the cylindrical part (57), respectively.
A seal member (71) is provided around the spark plug insertion hole (55) on the lower surface of the holder (49).

The rocker arm support member (47) has a bridge portion (Sl
), a threaded part (47A) with an outer diameter that is vertically slidably fitted into the hole (85), a pin (73) protruding from the upper and lower intermediate parts of the threaded part (47A), and a threaded part (47A). The engaging part (47B) to the rocker arm fulcrum part (45A) formed at the lower end of the
).

The engaging portion (47B) is formed with a cylindrical surface (75) and side surfaces (77), (77) that can be freely engaged with the cylindrical surface (51) and side surfaces (53), (53) of the rocker arm (45), respectively. do.

The rocker arm support member (47) has a threaded portion (47A) fitted into the hole (85) of the bridge portion (6E), and nuts (79) and (79) on the upper and lower surfaces of the bridge portion (81), respectively.
Tighten the screw part (47A) with the bridge part (61).
The fulcrum part (45) of the rocker arm (45)
A) is the engaging portion (47B) of the rocker arm support member (47).
) is engaged, and the rotation of the camshaft (21) causes the rocker arm (45) to swing around the fulcrum (45A), thereby driving the intake valves (15), (15) to open and close.

The rocker arm support member (47) is prevented from rotating relative to the bridge portion (81) by a pin (73) and a groove (87).
), and the rocker arm support member (47)
The rotation of the rocker arm (45) against the cylindrical surface (5
1), (75) and the sides (53), (77), and the valve clearance is adjusted using nuts (79),
The rocker arm support member (47) is loosened and tightened by <79).
) by moving it up and down with respect to the bridge part (61).

In addition, in the embodiment, as shown in FIG.
) side (77), (7?) and a hole (81)
'.

(83), both ends of which are locked in the chain holes (82) and (83), and a substantially concave-shaped clip (85) is locked from below the rocker arm fulcrum part (45A), and the holder (43)
When the rocker arm (45) is removed from the cylinder head (5), the rocker arm (45) can be removed together with the rocker arm support member (47).

Since this embodiment is configured as described above, the rocker arm (
45) can be removed, thereby reducing the weight of the rocker arm (45) and improving the high-speed followability of the intake valve (15).

In addition, since the clip (85) is provided in the embodiment, when the holder (61) is removed, the rocker arm support member (47)
At the same time, the rocker arm (45) can be removed, making it easy to maintain the valve train, and lubricating oil supplied to the rocker arm fulcrum (45A) can be supplied from the clip retaining holes (81) and (83). The lubricating oil can be discharged to the outside of the rocker arm (45) and can prevent lubricating oil from pooling inside the rocker arm fulcrum (45A).

Next, a second embodiment of the present invention will be described with reference to FIGS. 6 and 7.

FIG. 6 is a cross-sectional side view of the main part of the cylinder head, and FIG. 7 is a plan view thereof.

In the second embodiment, the holder (49) that supports the rocker arm support member (47) is replaced with the cam holder (31) that supports the camshaft (21). The point provided separately from the above is the first point.
This is different from the example.

In the second embodiment, the holder (49) is attached to the cylindrical portion (57).
) on both sides of the cylinder head (5) with (93).
) and attach the cam holder (91) to the bolts (85) on both sides of the cam shirt (21).
) to the cylinder head (5).

Further, in the second embodiment, intake valve cam portions (21) are provided on the camshaft (21) on both sides of the cam holder (91).
B), (21B) are formed, and the cam portions (21B), (21B) are formed.
1B), the rocker arm (45) and the slipper surface (45B) of (45), respectively.

(45B) is engaged.

In addition, in the embodiment, the fulcrum part (
45A) and the engaging portion (4) of the rocker arm support member (47).
7B) is formed from a cylindrical surface and side surfaces on both sides of the cylindrical surface, but such a structure may optionally be formed, for example, from a spherical surface and side surfaces on both sides of the cylindrical surface.In short, the rocker arm support member (47) On the other hand, any structure is sufficient as long as the rocker arm (45) can swing in a fixed direction.

In addition, in the embodiment, the rocker arm fulcrum part (45A)
cam shirt on both sides) (21) engaging part (45B)
The rocker arm (45) is formed with the engaging portion (45D) for the intake valve (15).
1) and an engaging part (45D) for the intake valve (15) may be formed, and the valve operating device is limited to the OHC type as in the embodiment. It is optional.

(Effects of the Invention) As is clear from the above description, according to the present invention, the weight of the port arm can be reduced by removing the adjustment screw from the rocker arm, and the high-speed followability of the intake and exhaust valves can be improved. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional side view of a main part of a cylinder head according to a first embodiment of the present invention, FIG. 2 is a plan view of the same, and FIG.
4 and 5 are sectional views taken along lines rV-IV and -V in FIG. 1, respectively. FIG. The figure is a plan view of the same. In the drawing, (3) is the cylinder block, (5) is the cylinder head, (7) is the cylinder pore, (15) is the intake valve, (
17) is an exhaust valve, (21) is a camshaft, (45) is a rocker arm, (47) is a rocker arm support member, (4
8) is a holder.

Claims (1)

[Scope of Claims] Two points spaced apart from the fulcrum in the longitudinal direction engage with the camshaft and the top of an intake or exhaust valve, respectively, and when the camshaft rotates, the fulcrum is centered on the fulcrum. In a valve operating system for an internal combustion engine, in which a rocker arm is disposed on a cylinder head to open and close the valve, the fulcrum part of the rocker arm is open above the cylinder head and perpendicular to the rocking direction of the rocker arm. The structure consists of a cylindrical surface that is concave downwards in the cylinder head, the axis of which extends in the direction of a rocker arm support member is provided vertically so as to be vertically adjustable; an engaging portion having an engagement surface that can be freely engaged with the cylindrical surface and both side surfaces of the cylindrical surface is formed at the lower end of the rocker arm support member; and the rocker arm A valve operating system for an internal combustion engine, characterized in that the rocker arm is supported by engaging an engaging portion of the support member with a fulcrum portion of the rocker arm.