JP3135325B2 - Cam shaft - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camshaft used for an internal combustion engine or the like.

[0002]

2. Description of the Related Art A conventional camshaft is disclosed in
What is described in 97707 gazette is known. As shown in FIGS. 5 to 10, this camshaft is formed by fitting a cylindrical shaft main body 1 to a cam 2, and an outer surface of a portion of the shaft main body 1 to which the cam 2 is attached has A ridge 3 extending in the circumferential direction is formed by means such as rolling (FIG. 7). On the other hand, the diameter of the perfect circular mounting hole 4 of the cam 2 to be fitted into the shaft main body 1 is formed to be slightly larger than the outer diameter of the ridge 3, and a plurality of protrusions are formed on the inner surface of the mounting hole 4. 5 are formed. The diameter of a circle formed by connecting the tips of the protrusions 5 is smaller than the diameter of the ridge 3.

When the ridge 3 of the shaft body 1 is press-fitted into the cam 2, as shown in FIGS. 7 and 9, the protrusion 5 provided in the mounting hole 4 of the cam 2 makes the ridge 3 of the shaft body 1 fit. By cutting, a groove (see FIG. 10) is formed, and the cam 2 is fixed to the shaft main body 1 so as to be non-rotatable by the engagement between the groove and the protrusion 5.

In such a conventional camshaft, a cam 2 is formed by engagement of a projection 5 with a groove formed by cutting.
Since the shaft 2 and the shaft main body 1 are fixed, there is an advantage that the cam 2 has high anti-idling properties.

In the above-mentioned conventional technique, since the ridge 3 is cut by the projection 5, chips are generated by the cutting, and the chips adhere to the surfaces of the shaft body 1, the cam 2, and the like. Would. For this reason, there is a problem that the chips must be removed by means such as washing.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a camshaft which generates a small amount of chips when the camshaft is mounted on a cam.

[0007]

The camshaft according to the present invention comprises:
The mounting hole is formed in a polygonal shape in which the inscribed circle is smaller than the outer diameter of the ridge and the circumscribed circle is larger than the outer diameter of the ridge.
A projection is formed on the plane portion so as to project inward and abut on the ridge to cut the ridge.

[0008]

According to the camshaft of the present invention, the ridge of the shaft body is brought into contact with the inner surface of the polygonally formed mounting hole by press-fitting the shaft body into the cam, and the ridge is mainly plastically deformed. At the same time, the cam can be fixed to the shaft main body by cutting the projection with the projection to form a groove and engaging the groove with the projection. That is, the camshaft of the present invention can fix the cam and the shaft main body not only by the engagement of the projection with the groove but also by the plastic deformation of the projection by bringing the projection into contact with the inner surface of the mounting hole.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A camshaft according to an embodiment of the present invention will be described with reference to FIG. The same components as those of the conventional cam shaft are denoted by the same reference numerals, and the description will be simplified.

In the camshaft of this embodiment, the mounting hole is
The inscribed circle is slightly smaller than the outer diameter of the ridge 3, the circumscribed circle is formed in a regular hexagonal shape slightly larger than the outer diameter of the ridge 3, and two opposing two The camshaft is different from the conventional camshaft in that a protruding portion 42 that protrudes inward and abuts on the ridge 3 to cut the ridge 3 is formed on the flat portion 41. . here,
The distance between the two projections 42 is greater than the outer diameter of the shaft main body 1, so that the projections 42 do not interfere with the shaft main body 1.

The camshaft of this embodiment can also be assembled by press-fitting the ridge 3 of the camshaft 1 into the mounting hole 40 of the cam 20 as in the prior art. Here, in the camshaft of this example, the mounting hole 40 is formed in a hexagonal shape,
Since the inscribed circle is smaller than the outer diameter of the ridge 3, the ridge 3 is plastically deformed by the flat portion 41 of the mounting hole 40 during assembly, and the cam 20 is moved by the plastic deformation. Can be fixed to

Further, according to the camshaft of the present embodiment, simultaneously with the plastic deformation of the ridge 3, the ridge 3
Is cut to form a groove, and this groove can be engaged with the projection 42.

Therefore, according to the camshaft of this embodiment, the cam 20 can be fixed to the shaft main body 1 by both the protrusion 42 and the mounting hole 40 formed in a hexagonal shape. Therefore, even if the size of the projection 42 is formed smaller than that of the conventional projection 5, or the number of the projections 42 is smaller than that of the conventional projection 5, the cam has the same size as that of the conventional projection 5. The same high anti-idling property can be provided. Therefore, there is an advantage that the amount of chips generated can be greatly reduced as compared with the conventional camshaft.

In the above-described camshaft of this embodiment,
The mounting hole 40 of the cam 20 is formed in a regular hexagonal shape. However, the present invention is not limited to this. If the shape is a polygonal shape, the cam 20 and the shaft main body 1 are fixed by plastically deforming the ridge 3 as described above. Can be. Further, in the camshaft of the present example, two projections 42 are provided, but it is obvious that three or more projections 42 may be provided.

Further, in the camshaft of the present embodiment, the projection 42 has a rectangular shape. However, as shown in FIGS. 2 to 4, a triangular shape, a shape in which the inner surface bulges into a cylindrical surface, It may be trapezoidal. In the case of a triangular shape, the shaft body 1
Force required for press-fitting the cam 2 into the cam 2 can be reduced,
According to the latter two, there is an advantage that the corners of the projections 42 are not easily damaged when the shaft main body 1 is pressed into the cam 20.

[0016]

According to the camshaft according to the present invention, the mounting hole is formed in a polygonal shape in which the inscribed circle is smaller than the outer diameter of the ridge and the circumscribed circle is larger than the outer diameter of the ridge. In the department,
Since the protrusion projecting inward and being formed in contact with the ridge to cut the ridge is formed, the size of the protrusion is formed smaller than that of the conventional protrusion, or the protrusion is formed. Even if the number of parts is smaller than the conventional protrusion, the cam,
It is possible to provide the same anti-idling property as the conventional one.
Therefore, the amount of chips generated can be significantly reduced as compared with the conventional camshaft.

[Brief description of the drawings]

FIG. 1 is a front view of a cam used for a cam shaft according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part showing a modification of the camshaft according to the present embodiment.

FIG. 3 is an enlarged view of a main part showing a modification of the camshaft of the present embodiment.

FIG. 4 is an enlarged view of a main part showing a modified example of the camshaft of this embodiment.

FIG. 5 is a perspective view showing a conventional camshaft.

FIG. 6 is a front view of a conventional cam.

FIG. 7 is a side view showing a state where a conventional cam is attached to a shaft main body.

FIG. 8 is a side view showing a state where a conventional cam is attached to a shaft main body.

FIG. 9 is an enlarged view of a portion A in FIG. 7;

FIG. 10 is a sectional view taken along the line BB of FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft main body 3 Protrusion 20 Cam 40 Mounting hole 41 Flat part 42 Projection

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Lucas Matt Richtinstein 9492 Essien (no address) Press und Stanzberg Agg (56) References JP-A-2-150541 (JP, A) 63-297707 (JP, A) JP-A-5-172207 (JP, A) JP-A-5-10340 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F01L 1 / 04 F16H 53/02 F16B 4/00

Claims (1)

(57) [Claims] 1. A shaft body having a ridge formed on an outer surface thereof is fitted into a mounting hole formed in a cam, and the ridge is pressed into the mounting hole to fix the cam to the shaft body. Wherein the mounting hole is formed in a polygonal shape having an inscribed circle smaller than an outer diameter of the ridge and an circumscribed circle larger than an outer diameter of the ridge, and a planar portion thereof. A projection projecting inward, and abutting against the projection to cut the projection, is formed, and the flat portion plastically deforms the projection of the shaft main body.
Camshaft, characterized in that it.