JPH0355765Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a tappet lubrication device for a four-stroke engine that slides up and down in the tappet chamber.

The DOHC type valve mechanism of the 4-stroke engine is the first
As shown in the figure, the valves 1 and 2 are opened and closed by bringing cams 7 and 8 into contact with tappets 5 and 6 mounted on the upper ends of the valve stems 3 and 4 of the pivot valves 1 and 2. The tappets 5 and 6 are precisely guided into the tappet chambers 9 and 10, and shims 1 are provided on the top surface to rub against the cams 7 and 8.
1 and 12 are fitted. This tapepet 5 and 6
Oil is supplied to the sliding surfaces from oil reservoirs 15 and 16 at the bottoms of the cam chambers 13 and 14. However, the pivot valves 1 and 2 are generally inclined and the tappets 5 and 2 are generally inclined.
6 also operates tilted at an inclination angle α, the sliding movement between the tappet chambers 9 and 10 has good lubrication on the lower side of the slope, but tends to lack lubrication on the upper side. This causes problems such as tappet noise and reduced durability.

The purpose of this invention was to eliminate the above-mentioned problems and to provide a sufficient amount of lubricating oil to the upper side of the tappet to form an oil film to prevent tappet noise and decrease in durability. A tappet lubrication device is provided.

An embodiment of this invention will be described below with reference to the drawings.

FIG. 2 is a perspective view of a single tapepet 21 used in this invention, and FIG. 3 is a longitudinal cross-sectional view of the same with a shim 22 fitted therein. On the outer periphery of the top surface 27 of the tapepet 21,
A ring-shaped outer peripheral protrusion 23 is formed to protrude upward. The bottom surface of the shim 22 is brought into contact with the top surface 27 of the tappet 21, and the side surface of the shim 22 is brought into close contact with the inner peripheral surface of the outer circumferential flange 23, so that the shim 22 is fitted into the tappet 21. A plurality of notches 24, for example, four notches 24, are provided on this outer peripheral protrusion 23. These 4 notches 2
Two of the notches 24 facing each other are installed in the diametrical direction of the outer circumferential flange 23 . Further, the bottom surface 28 of each notch 24 is parallel to the top surface 27 of the tapepet 21 and is formed above this top surface 28.

When the tapepet 21 constructed in this manner is used by slidingly fitting into the tappet chamber 25 formed at an angle on the cylinder head, as shown in FIG. 25
A plurality of recesses are formed surrounded by the inner peripheral surface of the recess. As this tappet 21 rotates during operation, each notch 24 successively passes through an oil reservoir 26 on the lower side of the slope, collecting oil in each recess and transporting it upward. The carried oil flows down from each recess to the upper side of the tappet side surface, forms an oil film in the gap with the tappet chamber 25, and is used for lubrication.

As described above, the tappet lubrication device for a four-cycle engine according to this invention has a notch formed in the outer circumferential rim of the tappet, and the tappet is connected to the outer circumferential surface of the shim installed in close contact with the inner circumferential surface of the outer periphery flange. Since a recess is formed between the inner circumferential surface of the tapepet chamber to accommodate the tappet and the above-mentioned notch, this notch draws up oil from the oil reservoir on the lower side of the slope by the rotational action of the tapepet and transports it to the upper side. , it is possible to supply oil abundantly over the entire side surface of the tappet, preventing tappet noise and wear. Further, when replacing the shim, the notch is used to insert the tip of a tool and remove the shim, and since a plurality of these notches are arranged, the workability is improved.

Furthermore, since four notches are provided, a sufficient amount of lubricating oil can be carried by the notches. Therefore, the tappet side surface can be sufficiently lubricated over the entire circumference, and generation of tappet noise etc. can be prevented. These four notches were formed in the diametrical direction of the outer circumferential flange, so the two diametrically opposed notches
It is possible to form 4 notches in one step.
It can be manufactured in two steps with individual notches. Therefore, even if four notches are formed, the manufacturing cost does not increase.

Furthermore, since the bottom surface of the notch is formed above the top surface of the tappet, the lower portion of the bottom surface of the notch serves as a dam, allowing lubricating oil to be stored between the bottom surface of the shim and the top surface of the tappet. Therefore, the amount of lubricating oil carried by the tappet can be increased. In addition, since the bottom surface of the notch is formed in a flat shape parallel to the top surface of the tappet, the lubricating oil stored in the notch is less It is possible to prevent unnecessary outflow of

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view illustrating the area around the cylinder head of a 4-cycle engine, Fig. 2 is a perspective view of a tappet showing an embodiment of the tappet lubrication device for a 4-stroke engine according to this invention, and Fig. 3 is a longitudinal sectional view of the same. FIG. 4 is a side view showing the same operating state. 21... Tappet, 22... Shim, 23... Outer peripheral flange, 24... Notch, 25... Tappet chamber,
26... Oil reservoir, 27... Top surface of tapepet,
28... Bottom of the notch.

Claims (1)

[Scope of utility model registration request] In the tappet chamber of the cylinder head, a tappet that transmits the operation of the cam to the valve is arranged so as to be slidable and inclined, and the top surface of this tappet is formed with an outer circumferential ridge that protrudes upward. A shim is installed in close contact with the inner circumferential surface of the outer circumferential edge, and four notches are formed in the outer circumferential edge. A tappet lubrication device for a four-cycle engine, wherein the bottom surface of the notch is provided above and parallel to the top surface of the tappet with which the shim comes into contact.