JPS6343362Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a roller tappet for an internal combustion engine.

Fig. 1 shows a valve mechanism in a general internal combustion engine. To explain this simply, 1 is a camshaft, and when this camshaft 1 rotates, a cam 11 formed on it causes a tappet to move. 2, which swings a rocker arm 5 supported on a rocker shaft 4 via a bushing rod 3, thereby operating an intake and exhaust valve 6.

By the way, conventionally, the tapepet has a dish-shaped head 1 at the lower end of the tapepet body 13c as shown in FIG.
There are flat tappets and roller tappets, each of which has a roller 12 protruding downward from the lower end of the tappet body 13a, as shown in FIG. Tappet body 13 as shown.
A semi-submerged type roller tappet in which a roller 12 is provided in a semi-submerged state at the lower end of b is known, but rolling contact with a roller tappet causes less wear and is more durable than sliding contact with a flat tapepet. There are advantages to being

However, roller tappets have the disadvantage that the thrust load is greater than that of flat tappets. This occurs when the cam contacts the lower end of a flat tapepet, but it is necessary to rotate the roller, and the cam contacts the cam nose. Particularly, as shown in Figure 2, in the case of a roller tappet with a protruding roller. causes a moment M, which has a negative effect on the lifting height of the roller tappet.

On the other hand, as shown in Fig. 3, the roller tappet of the semi-submerged roller type generates almost no moment, but on the other hand, since the roller 12 is built in in a semi-submerged state, the diameter of the tapepet body 13b becomes thicker. It had the disadvantage of being large and heavy.

Further, in Japanese Utility Model Application Publication No. 51-160707, a holding member 3 is constructed of a spring material in a pair of cylindrical holes 12 and 13 for roller tappets, and is generally U-shaped as a whole.
0 is inserted and engaged, and the flat surfaces 21, 2 of the roller type driven members 14, 15 are inserted and engaged with the pair of leg portions 32 of the roller type driven members 14, 15.
A roller-type driven device is disclosed that includes a rotation-preventing retainer that contacts 2 and prevents rotation of the driven member within the cylindrical hole.

However, this known technology does not have a configuration in which a slit-like cut groove is provided at the lower end of the tapepet body to thereby form a tongue-like skirt portion, and therefore a good oil film formation state cannot be obtained and the There is a problem that it lacks skating properties.

The present invention eliminates the above-mentioned drawbacks, and without generating moments due to thrust loads,
The purpose of the present invention is to provide a simple roller tappet that is lightweight, compact, and has excellent scuff resistance.

The gist of this is to make the diameter of the tapepet body as close as possible to the length of the diagonal line in the projection plane of the roller tapepet of a roller tapepet in which a roller is provided at the lower end of the tapepet body in a semi-submerged state. This is a roller tappet formed by providing a tongue-shaped skirt portion with a tongue-shaped cut groove.

The present invention will be explained below with reference to an embodiment shown in FIGS. 4 to 7.

Note that the same parts as in the conventional example are given the same reference numerals.

Reference numeral 13 denotes a tapepet body, the diameter of which is made sufficiently smaller than the conventional tapepet body 13b. That is, the diameter Dmm is as shown in FIG.
Diagonal length lmm on the projection plane of the roller 12
It has been made slightly larger. If the diameter Dmm of the tapepet body 13 is made even slightly smaller than the length lmm of the diagonal line on the projection plane of the roller 12, the roller 12 will protrude from the circumferential surface of the tapepet body 13.
The problem arises that the lift height is hindered.

Since the conventional roller 12 is used as the roller 12, the recess 15 for accommodating the roller provided at the lower end of the tapepet body 13 has the same size as the conventional roller. A slit-shaped cut groove 16 communicating with the depression 15 is provided in the tapepet body 13 near the maximum diameter part of the roller 12 corresponding to the corner part of the depression 15, and four tongue-shaped skirt parts 17a are formed at the lower end of the tapepet body 13. , 17b, 17
c, 17d are formed. The roller 12 has its shaft 18 rotatably supported by the skirt portions 17a, 17b.

In the roller tappet constructed as described above, when the internal combustion engine operates and the camshaft 1 rotates, the cam 11
A thrust load is applied by the skirt portion 17c of the tapepet body 13.
The resistance against the thrust load is almost the same as that of a semi-submerged roller tappet as shown in FIG. 3, and no moment is generated.

As described above, according to the present invention, the tapepet body 1
3 is smaller than the conventional one of the same type, it is lighter and more compact, and the generation of moment can be prevented, so there is no problem with the lifting height of the roller tappet, and the skirt portion 17c has a high rigidity. Since it is slightly smaller than other parts, it has good oil film formation and excellent scuff resistance.

Furthermore, the present invention has the advantage that it can be manufactured without major design changes because the diameter of the tapepet body is reduced and the slit-like cut grooves are provided.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway vertical sectional view showing a general valve mechanism, Figs. 2 and 3 are partially cutaway enlarged views of the main parts of a conventional roller tappet and its driving member, and Figs. FIG. 5 is a partially cutaway enlarged view of essential parts showing an embodiment of the present invention, FIG. 4 is a side view, FIG. 5 is a front view, and FIG. 6 is a sectional view taken along the line - in FIG. FIG. 7 is a projection view. 12... Roller, 13... Tappet body,
16... Cut groove, 17a, 17b, 17c, 1
7d...Skirt section.

Claims (1)

[Scope of utility model registration request] The diameter of the tapepet body of a roller tapepet is provided with a roller in a semi-submerged state at the lower end of the tapepet body as close as possible to the length of the diagonal line in the projection plane of the roller, and a slit-like cut groove is provided at the lower end of the tapepet body to provide a tongue piece. A roller tappet with a shaped skirt.