JP2526710Y2 - Camshaft - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a camshaft used for a valve opening / closing mechanism of an automobile engine.

[0002]

2. Description of the Related Art A camshaft used for a valve opening / closing mechanism of an automobile engine plays an important role in obtaining rotation from a crankshaft and transmitting power to the valve mechanism. Have been used. However, such a solid cast product has a problem that the manufacturing cost is high because it is heavy and it is necessary to cast a complicated shape.

In order to reduce the weight, a number of camshafts having a cam mounted on a pipe-shaped hollow shaft have recently been proposed. However, as shown in, for example, JP-A-61-248912 and JP-A-57-81950,
Since each of these has a structure in which a cam with a through hole is fitted from one end of a pipe-shaped hollow shaft, it is not easy to reliably fix the cam to a predetermined position of the hollow shaft,
For example, Japanese Patent Application Laid-Open No. 61-248912 requires a complicated manufacturing process such as bulging a hollow shaft. Moreover, such a conventional camshaft cannot completely eliminate the possibility that the cam is displaced on the hollow shaft during use.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and is lightweight and inexpensive to manufacture. Moreover, the cam can be easily mounted, so that the cam can be used in both the rotational direction and the axial direction during use. The present invention has been completed in order to provide a camshaft in which the cam is not likely to be displaced.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an arcuate surface in which an annular groove is formed on an outer peripheral surface of a pipe and an inner peripheral surface thereof corresponds to an inner surface of the annular groove. Join
At the same time, a plate-like cam having a projection fitted into the through hole in the annular groove is fitted inside the annular groove, and the side surface of the plate-like cam is held on the side surface of the annular groove. It is characterized by having.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the embodiments shown in the drawings. 1 and 2 show a first embodiment of the present invention, wherein 1 is a metal pipe having high hardness and strength, and 2 is an annular pipe formed by cutting the outer peripheral surface of the pipe 1 into an annular shape. It is a groove. The width of the annular groove 2 is made smaller than the width of the cam follower 3, and the section in which the valve lift is zero is configured so that the cam follower 3 can directly contact the outer peripheral surfaces of the pipes 1 on both sides of the annular recess 2 and rotate. It should be noted that various types of cam followers 3 such as tappets and rocker arms can be used according to the type of valve mechanism.

Reference numeral 4 denotes a plate-like cam fitted inside the annular concave portion 2. The plate-like cam 4 can be made of, for example, a ductile casting whose surface is chilled, or a hard steel such as bearing steel, tool steel, or carburized steel. The outer peripheral surface of the plate-like cam 4 is machined into a mountain-shaped cam shape, and the inner peripheral surface is machined into an arc surface corresponding to the inner surface of the annular groove 2. A protrusion 5 is formed on the inner periphery of the plate-like cam 4. The protrusion 5 is fitted into a through hole 6 formed in the annular groove 2 of the pipe 1, so that the plate-like cam 4 can rotate in the rotation direction. Displacement is prevented. The width of the plate-like cam 4 corresponds to the width of the annular groove 2. By holding the side surface of the plate-like cam 4 on the side surface of the annular groove 2, the plate-like cam 4 is displaced or rattled in the axial direction. Has been prevented. Further, it is preferable that both ends 7 of the plate-like cam 4 are fixed to the pipe 1 inside the annular groove 2 by an appropriate method such as welding or brazing.

In the second embodiment shown in FIG. 3, rings 8 made of hard steel such as bearing steel, tool steel, carburized steel and the like are fitted on both sides of the annular concave portion 2 of the pipe 1. The ductile casting whose surface has been chilled has a hardness of about 54 to 55 HRC, but the ring 8 of carburized steel has a hardness as high as 60 to 62 HRC. The abrasion resistance of the contact surface can be further improved than that of the first embodiment. In the second embodiment, the ceramic chip 9 is embedded in the outer peripheral surface of the plate-like cam 4,
The wear resistance of the plate cam 4 is also improved. As a material of the ceramic chip 9, ceramics having excellent wear resistance, such as alumina and zirconia, can be selected.

[0009]

The camshaft of the present invention constructed as described above has a configuration in which the plate-like cam 4 pushes up the cam follower 3 in the state shown in the figure, and when the plate-like cam 4 rotates downward, the cam follower 3 becomes an annular concave portion of the pipe 1. 2 is kept in contact with the circumferential surfaces on both sides, whereby the valve opening / closing mechanism can be operated as in the related art.

The camshaft of the present invention is different from the conventional one in that an inner surface is formed in an annular groove 2 formed in a hollow pipe 1 .
The inner peripheral surface is processed into an arc surface corresponding to the inner surface of the annular groove 2.
At the same time, a plate-like cam 4 having a projection 5 fitted into the through hole 6 in the annular groove is fitted and its side surface is held by the side surface of the annular groove 2. For this reason, the camshaft of the present invention not only facilitates the mounting of the plate-like cam 4, but also the mounted plate-like cam 4
There is no risk of displacement in the rotational direction above. In addition, since the side surface of the plate-like cam 4 is held by the side surface of the annular groove 2, the displacement in the axial direction can be reliably prevented without rattling. Further, if the plate-like cam 4 is fixed to the pipe 1 inside the annular groove 2 by welding or the like as in the embodiment, more secure mounting is possible. Further, in this case, there is no possibility that the welded portion comes into contact with the cam follower 3, so that there is an advantage that the welded portion does not need to be processed later.

Although only one plate-like cam 4 is shown in the drawings, a plurality of plate-like cams 4 are actually mounted on the same pipe 1 with their phases shifted at predetermined intervals.
Also in this case, if the positions of the annular groove 2 and the through hole 6 are accurately determined, the plate-like cam 4 can be mounted without errors in phase and pitch.

[0012]

As described in detail above, the camshaft of the present invention has an annular groove formed on the outer peripheral surface of the pipe, and the inner peripheral surface is made to correspond to the inner surface of the annular groove inside the annular groove. Was
Since it is processed into an arc surface, a plate-like cam with a projection is fitted on the inner surface and its side surface is held on the side surface of the annular groove, so it is lightweight and easy to manufacture, and the plate-like cam can be used. It can be securely attached without fear of rattling or displacement. Therefore, the present invention has a very large practical value as a camshaft which has solved the conventional problems.

[Brief description of the drawings]

FIG. 1 is a sectional view, parallel to an axis, showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the first embodiment of the present invention, which is perpendicular to the axis.

FIG. 3 is a cross-sectional view parallel to the axis showing a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pipe 2 Annular groove 3 Cam follower 4 Plate cam 5 Projection 6 Through hole 7 Both ends 8 Ring 9 Ceramic chip

Claims (1)

(57) [Scope of request for utility model registration] 1. A forming an annular groove on the outer circumferential surface of the pipe, the inner peripheral
When the surface is processed into an arc surface corresponding to the inner surface of the annular groove
In both cases, a plate-like cam having a projection fitted into a through hole in the annular groove is fitted inside the annular groove, and the side surface of the plate-like cam is held on the side surface of the annular groove. Camshaft.