JPH05256109A - Camshaft - Google Patents

Abstract

PURPOSE: To greatly reduce the generation of chips by forming a mounting hole with its inscribed circle smaller than the outer diameter of the outer protrusion strip of a shaft, its circumcircle being of a polygon larger than the outer diameter of the outer protrusion strip, and a protrusion formed on a plane portion thereof, protruding inwardly, abutting the protrusion strip for cutting the protrusion strip. CONSTITUTION: A camshaft is assembled by pressing the protrusion strip of the camshaft into a mounting hole 40 of a cam 20. The mounting hole 40 is of a hexagonal shape. As the inscribed circle thereof is smaller than the outer diameter of the protrusion strip, the protrusion strip is plastically deformed by a plane portion 41 of the mounting hole 40 during assembly. The cam 20 is secured on a shaft body by elastic deformation. The protrusion strip is cut by a protrusion 42 of the cam 20 to form a groove which is engaged with the protrusion 42. Thus, even if the size of the protrusion 42 is small and the number of the protrusion 42 is a few, the cam 20 is provided with a high resistance against idle rotation. Therefore, the generation of chips of the camshaft is greatly reduced.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art As a conventional camshaft, Japanese Patent Laid-Open No. 63-2
The one described in Japanese Patent Publication No. 97707 is known. As shown in FIGS. 5 to 10, this cam shaft is formed by fitting a cylindrical shaft body 1 into a cam 2, and the outer surface of the portion of the shaft body 1 to which the cam 2 is attached is The ridges 3 extending in the circumferential direction are 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 body 1 is formed to be slightly larger than the outer diameter of the projection 3, and the inner surface of the mounting hole 4 has a plurality of protrusions. 5 is formed. The diameter of the circle formed by connecting the tips of the protrusions 5 is smaller than the diameter of the protrusions 3.

When the projection 3 of the shaft body 1 is press-fitted into the cam 2, the projection 5 provided in the mounting hole 4 of the cam 2 causes the projection 3 of the shaft body 1 to be inserted into the projection 3 as shown in FIGS. A groove (see FIG. 10) is formed by cutting, and the cam 2 is non-rotatably fixed to the shaft body 1 by the engagement of the groove and the protrusion 5.

In such a conventional cam shaft, the cam 2 is formed by the engagement between the groove formed by cutting and the protrusion 5.
Since the shaft main body 1 and the shaft main body 1 are fixed to each other, there is an advantage that the cam 2 has a high anti-idling property.

By the way, in the above-mentioned prior art, since the ridge 3 is cut by the protruding portion 5, chips are generated by this cutting, and the chips adhere to the surfaces of the shaft body 1, the cam 2, and the like. Will end up. 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 an object of the present invention is to provide a camshaft which produces a small amount of chips when the camshaft is attached to the cam.

[0007]

A 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.
The flat portion is formed with a projection portion that projects inward and is brought into contact with the ridge to cut the ridge.

[0008]

In the camshaft of the present invention, the projection of the shaft main body is brought into contact with the inner surface of the mounting hole formed in a polygonal shape by press-fitting the shaft main body into the cam, and the projection is mainly plastically deformed. At the same time, the protrusion can be cut by the protrusion to form a groove, and the groove can be engaged with the protrusion to fix the cam to the shaft body. That is, the camshaft of the present invention can fix the cam and the shaft main body not only by engaging the protrusion and the groove but also by plastically deforming the protrusion by contacting 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 designated by the same reference numerals to simplify the description.

In the camshaft of this embodiment, the mounting hole is
The inscribed circle is slightly smaller than the outer diameter of the ridge 3 and the circumscribed circle is formed in a regular hexagonal shape slightly larger than the outer diameter of the ridge 3, and two of the six flat surface portions 41 facing each other are formed. This is different from the conventional camshaft in that the flat surface portion 41 is formed with a protrusion 42 that protrudes inward and is brought into contact with the protrusion 3 to cut the protrusion 3. . here,
The distance between the two protrusions 42 is larger than the outer diameter of the shaft body 1, so that the protrusions 42 do not interfere with the shaft body 1.

The cam shaft of this embodiment can also be assembled by press fitting the protrusion 3 of the cam shaft 1 into the mounting hole 40 of the cam 20 as in the conventional case. Here, in the cam shaft 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 surface portion 41 of the mounting hole 40 at the time of assembly, and this cam deformation causes the cam 20 to move the cam 20. Can be fixed to.

Further, according to the cam shaft of this embodiment, at the same time as the plastic deformation of the ridge 3 described above, the ridge 3 is formed by the protrusion 42.
Can be cut to form a groove, and the groove and the protrusion 42 can be engaged with each other.

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

In the above-mentioned cam shaft of this example,
Although the mounting hole 40 of the cam 20 is formed in a regular hexagonal shape, the shape is not limited to this, and if the mounting hole 40 is a polygonal shape, the protrusion 3 may be plastically deformed to fix the cam 20 and the shaft body 1 as described above. You can Further, in the cam shaft of this example, two protrusions 42 are provided, but it is needless to say that the number may be three or more.

Further, in the camshaft of this example, the protrusion 42 is rectangular, but as shown in FIGS. 2 to 4, it has a triangular shape, a shape in which the inner surface bulges into a cylindrical surface, It may be trapezoidal. If it is triangular, the shaft body 1
It is possible to reduce the force required to press the cam into the cam 2.
According to the latter two, there is an advantage that the corners of the protrusions 42 are unlikely to be damaged when the shaft body 1 is press-fitted into the cam 20.

[0016]

In 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 protruding inward and brought into contact with the ridge and cutting 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 reduced compared to conventional protruding parts,
It is possible to impart a high anti-slip property to the same level as conventional ones.
Therefore, the amount of chips generated can be significantly reduced as compared with the conventional camshaft.

[Brief description of 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 an essential part showing a modified example of the cam shaft of the present example.

FIG. 3 is an enlarged view of a main part showing a modified example of the cam shaft of the present example.

FIG. 4 is an enlarged view of an essential part showing a modified example of the cam shaft of this example.

FIG. 5 is a perspective view showing a conventional cam shaft.

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

FIG. 7 is a side view showing a state in which a conventional cam is attached to a shaft body.

FIG. 8 is a side view showing a state in which a conventional cam is attached to a shaft body.

9 is an enlarged view of part A in FIG. 7. FIG.

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

[Explanation of symbols]

 1 Shaft main body 3 Projection 20 Cam 40 Mounting hole 41 Plane 42 Projection

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hachiro Matsunaga 1-3, Kogane-cho, Niigata City, Niigata Prefecture Mitsubishi Material Co., Ltd. Niigata Plant (72) Inventor Lucas Matt Richtinstein 9492 Eschen (no address) Press Undsch Tanzberg In the AG

Claims (1)

[Claims] 1. A shaft main body having a ridge formed on its outer surface is fitted into a mounting hole formed in a cam, and the ridge is press-fitted into the mounting hole to fix the cam to the shaft main body. The mounting hole is formed in a polygonal shape having an inscribed circle smaller than the outer diameter of the ridge and a circumscribed circle larger than the outer diameter of the ridge, and the plane portion thereof. The camshaft is characterized in that the camshaft is formed with a projecting portion that projects inwardly and is brought into contact with the ridge to cut the ridge.