JPH0814021A - Lubrication device for tappet in cylinder head - Google Patents

Abstract

PURPOSE:To increase supply quantity of lubricating oil to a sliding face between a cylindrical fitting hole and a tappet so as to suppress generation of abration, scuffing, etc., on the sliding face. CONSTITUTION:A plurality of oil leading holes 4 are bored in a circumferential wall of a cylindrical fitting hole 3 for fittingly inserting a tappet provided in a cylinder head H so that lubricating oil easily flows into a sliding face between the cylindrical fitting hole 3 and the tappet 12 though the oil leading holes 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubrication device for a tappet fitted in an upper portion of a cylinder head of an internal combustion engine.

[0002]

2. Description of the Related Art A cylinder head of an engine having a direct-acting valve operating device has a bottomed cylindrical fitting hole for inserting and guiding a tappet of the valve operating device.

Conventionally, this fitting hole is generally formed as a mere smooth curved surface having a size capable of properly fitting the cylindrical body portion of the tappet.

[0004]

Therefore, the supply of the lubricating oil to the sliding surfaces of the fitting hole of the cylinder head and the cylindrical body of the tappet is performed only from the upper opening end of the fitting hole, and the sliding surfaces of the fitting holes are not connected to each other. The lubricity of the sliding surface was not always good.

Particularly, in the case where the cylinder head and the tappet are made of aluminum alloy of the same material, if the supply amount of the lubricating oil to the sliding surface is insufficient, the sliding surface may be worn in a short time. , Galling may occur.

The present invention has been made in order to solve the above-mentioned problems, and includes a cylindrical fitting hole in a cylinder head,
Lubricating device for a tappet in a cylinder head, in which the amount of lubricating oil supplied to the sliding surface of the tappet with respect to the cylindrical body is increased so that wear and galling of the sliding surface can be suppressed. Is intended to provide.

[0007]

According to the present invention, a plurality of oil guide holes are provided in the central portion in the axial direction of the peripheral wall of the cylindrical fitting hole for tappet insertion, which is provided in the upper portion of the cylinder head. Is provided along the circumferential direction.

[0008]

[Function] Lubricating oil is easily applied to the sliding surface between the fitting hole and the body of the tappet through the plurality of oil guide holes formed in the axial center of the peripheral wall of the cylindrical fitting hole for tappet insertion. Flows into
The lubricity of the sliding surface is improved.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows a cylinder head (H) on the exhaust side of a DOHC engine to which the present invention is applied and a direct drive type valve operating device (V) incorporated therein.

The cylinder head (H) is made of an aluminum alloy, and has an exhaust port (1) at its lower end, the outer end of which faces sideways and the inner end of which opens on the lower surface of the cylinder head (H). Has been formed.

Inside the downward recess (2) formed in the upper part of the cylinder head (H), an inner diameter of a size to which a body of a tappet (12) described later can be fitted and a movement stroke of the tappet or more are set. A bottomed cylindrical fitting hole (3) having a depth is formed by inclining the axis outward at a predetermined angle.

At the central portion in the axial direction of the sliding region of the tappet (12) on the peripheral wall of the cylindrical fitting hole (3), as shown in FIGS. Five oil guide holes (4) are provided at substantially equal intervals in the circumferential direction.

(5) is a valve guide which is coaxial with the cylindrical fitting hole (3) and is press-fitted into the cylinder head (H).
The lower end and the upper end thereof project into the exhaust port (1) and the cylindrical fitting hole (3), respectively.

The shaft portion (6a) of the exhaust valve (6) is vertically slidably fitted into the valve guide (5), and its umbrella portion (6b) is inserted.
Is the valve seat (7) fitted to the inner end of the exhaust port (1).
Close the exhaust port (1) in close contact with.

The valve operating device (V) includes a shaft portion (6) of the exhaust valve (6).
a) a pair of cotters (9) (9) fitted into the annular groove (8) on the outer peripheral surface of the end, a spring retainer (10) fixed by the cotters (9) (9), and a cylindrical shape The valve spring (11) compressed between the bottom surface of the fitting hole (3) and the lower surface of the spring retainer (10) and the upper end of the exhaust valve (6) are covered from above to form a cylindrical fitting hole. (3) It is composed of a tappet (12) that is slidably fitted in the inside of the tappet (12).

The tappet (12) is made of aluminum alloy, and the hard tip (13) fitted in the center of the lower surface of the top wall (12a) of the tappet (12) is the upper end of the shaft portion (6a) of the exhaust valve (6). Is in contact with.

A hard shim (15) for valve clearance adjustment is detachably fitted into a disc-shaped holding hole (14) formed on the upper surface of the top wall (12a). The rotating cam (16) is in contact with the upper surface of ().

When the rotary cam (16) rotates, the exhaust valve
(6) is driven up and down via the tappet (12) to open and close the exhaust port (1).

As described above, the cylinder head (H)
Since a plurality of oil guide holes (4) are provided in the cylindrical fitting hole (3) of the rotary cam (1)
Lubricating oil scattered by the rotating motion of 6) and the vertical motion of the tappet (12) easily slides between the cylindrical fitting hole (3) and the body of the tappet (12) through the oil guide hole (4). Flows into the surface.

As a result, the amount of lubricating oil supplied to the sliding surface between the fitting hole (3) and the tappet (12) is significantly increased as compared with the conventional one, and the lubricity is improved, and Wear of the sliding surface is suppressed.

Further, even if the fitting hole (3) and the tappet (12) are made of an aluminum alloy of a similar material, there is no risk of galling on the sliding surface.

Further, even if foreign matter such as metal powder intrudes into the sliding surface at the time of assembling the valve operating device (V), these are moved by the vertical movement of the tappet (12) to the oil guide hole. It is discharged promptly through (4).

The shape of the window hole (4) is not limited to the above-mentioned embodiment, but may be a slit-like vertically elongated hole or a large number of small circular holes.

The present invention provides the cylinder head on the exhaust side.
In addition to (H), it can be applied not only to the cylinder head on the intake side, but also to the cylinder head of a normal OHC engine in which the axis of the engine valve is not inclined.

[0025]

According to the present invention, the following effects can be obtained. (a) Since the amount of lubricating oil supplied to the sliding surface between the cylindrical fitting hole and the tappet is increased, the lubricity of the sliding surface is improved,
It is possible to suppress the occurrence of wear and galling.

(B) Even if foreign matter invades the sliding surfaces of each other at the time of assembly or the like, they are quickly discharged through the oil guide.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional front view of essential parts showing a cylinder head on the exhaust side of a DOHC engine to which the present invention is applied and a direct-acting valve operating device.

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

FIG. 3 is a left side view of FIG. 2;

[Explanation of symbols]

 (1) Exhaust port (2) Recess (3) Cylindrical fitting hole (4) Oil guide hole (5) Valve guide (6) Exhaust valve (6a) Shaft part (6b) Umbrella part (7) Valve seat (8) Annular groove (9) Cotter (10) Spring retainer (11) Valve spring (12) Tappet (12a) Top wall (13) Tip (14) Holding hole (15) Shim (16) Rotating cam (H) Cylinder head (V ) Valve drive

Claims (1)

[Claims] 1. A plurality of oil guide holes are provided along a circumferential direction at an axially central portion of a peripheral wall of a cylindrical fitting hole for tappet fitting, which is provided at an upper portion of a cylinder head. Lubrication device for tappet in cylinder head.