JPH0538528A - Assembled cam shaft and manufacture of the same - Google Patents

Abstract

PURPOSE:To obtain stable combined force and to facilitate the formation by narrowing the width of a base circle part in a cam piece downward, introducing pressurized fluid into a raw material pipe to expand and deform a raw material pipe, expanding and deforming the plate and integrally combining the cam piece and the raw material pipe. CONSTITUTION:An assembled cam shaft is provided with a cam piece 1 having a top part 2, a base circle part 3 and an inner peripheral face of a shaft hole and a raw material pipe 10 inserted into the shaft hole of the cam piece 1. The base circle part 3 in the cam piece 1 is formed so as to narrow the width downward. Then, by introducing the pressurized fluid having the prescribed pressure in the raw material pipe 10, the the raw material pipe 10 is expanded and deformed to integrally couple the cam piece with the raw material pipe. By this method, since the stable coupling force in the axial center direction and circumference direction in the cam piece 1 and the raw material pipe 10 is obtd. and the construction is easy, the formation can be facilitated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an assembled camshaft and a method of manufacturing the same, and more particularly to an assembled camshaft in which a cam piece and a material pipe are joined by bulging or the like and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, when a cam piece and a material pipe are joined together to manufacture an assembled camshaft, a pressure fluid is introduced into the material pipe while the cam piece is externally inserted into the material pipe by bulging. It is known that the cam piece and the raw material tube are connected to each other by swelling (see Japanese Patent Publication No. 2-62333).

According to the method for manufacturing an assembled camshaft described in this publication, a receiving projection is formed on the inner peripheral surface of the shaft hole corresponding to the high portion (top portion) of the cam piece and extends in the axial direction. With the material pipe inserted into the piece, a pressure fluid is introduced into the material pipe, whereby the receiving ridge of the cam piece and the part of the material tube facing it are swollen and deformed to bite the cam piece. The pressurization is stopped by the pressure fluid while a slight gap remains between the material pipe and the material pipe.

In this manufacturing method, the cam piece easily moves in the circumferential direction and the radial direction with respect to the material pipe, although the bulging is performed at a significantly lower pressure than the conventional method. Moreover, the cam piece is prevented from being damaged from the biting part with the material pipe.

[0005]

However, in the above-mentioned conventional manufacturing method of the assembled camshaft, since the bulging process is performed with a relatively low pressure, the material pipe is not limited to the cam piece, the journal piece or the like. When the above members are joined together, the pressure of the bulging process is low, and there arises a problem that a sufficient joining force between the material pipe and the other members such as the journal piece cannot be obtained. Further, since the receiving ridge of the cam piece is in a state of being embedded in the material tube, the material tube may be deformed by an external force acting in the axial direction from the top portion of the cam piece. Further, it is necessary to further improve the coupling force between the cam piece and the material pipe in the axial direction and the circumferential direction.

Therefore, the present invention has been made in order to solve the above-mentioned problems of the prior art, and it is possible to obtain a stable coupling force in the axial direction and the circumferential direction in the cam piece and the material pipe and structurally. It is an object of the present invention to provide an assembled camshaft which is simple and easy to form, and a manufacturing method thereof.

[0007]

In order to achieve the above object, an assembled camshaft of the present invention has a cam piece having a top portion, a base circle portion and an inner peripheral surface of a shaft hole, and a shaft hole of the cam piece. In the assembled camshaft having the inserted material tube, the base circle portion of the cam piece is formed so as to become narrower downward, and a pressure fluid having a predetermined pressure is introduced into the material tube. The feature is that the material pipe is bulged and deformed by introducing it, so that the cam piece and the material pipe are integrally connected.

In the assembled camshaft of the present invention, the base circle portion of the cam piece may be formed with a taper portion, and the side surface of the taper portion may be inclined at a predetermined angle. According to the method of manufacturing an assembled camshaft of the present invention, a cam piece having a top portion, a base circle portion, and an inner peripheral surface of an axial hole is provided, and the base circle portion of the cam piece is formed so as to become narrower downward. Then, the material tube is inserted into the shaft hole of the cam piece, and a pressure fluid having a predetermined pressure is introduced into the material tube to bulge and deform the material tube, whereby the cam piece and the material tube are integrated. It is characterized by the fact that it is combined with.

In the present invention thus constructed,
Since the base circle portion of the cam piece is formed so as to become narrower downward, the base circle portion of the cam piece and the material pipe are engaged with each other during bulging. Therefore, in the present invention, a stable coupling force in the axial direction and the circumferential direction can be obtained between the cam piece and the material pipe. Further, since the structure is simple, molding is easy.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of an assembled camshaft and a method of manufacturing the same according to the present invention will be described below with reference to FIGS. FIG. 1 is a front view showing a cam piece before bulge processing,
2 is a cross-sectional view taken along the line AA of FIG. 1, and FIG. 3 is a cross-sectional view of the assembled camshaft showing a state in which the cam piece and the material pipe are joined after the bulge processing.

As shown in FIG. 1, reference numeral 1 denotes a cam piece. This cam piece 1 has a top portion 2 protruding in the radial direction on one side and a base circle portion 3 on the other side. ing. As shown in FIG. 2, a taper portion 4 is formed on the base circle portion 3 of the cam piece 1 and becomes narrower downward. The cam piece 1 has a shaft hole 5, and the shaft hole 5 forms an inner peripheral surface 6.

The material pipe 10 is inserted into the inner peripheral surface 6 of the shaft hole 5 of the cam piece 1 thus formed.
As will be described later, a pressure fluid is introduced therein, and the material tube 10 is bulged and deformed, and the material tube 10 and the cam piece 1 are coupled. At this time, the material pipe 10 bites into the taper portion 4 of the base circle portion 3 of the cam piece 1 to obtain a stable coupling force in the axial direction and the circumferential direction. Therefore, as shown in FIG. 3, the taper portion 4 of the base circle portion 3 can receive the external force F1 acting on the shaft center and the external force F2 acting in the circumferential direction from the top portion 2.

FIG. 4 is a sectional view showing a cam piece used in another embodiment of the present invention. In this embodiment, the side surface of the taper portion 4 formed on the base circle portion 3 of the cam piece 1 is configured to be inclined by a predetermined angle α. The angle α of the embodiment shown in FIG. 4 is set larger than the angle of the embodiment shown in FIG. For this reason, the material pipe 10 bites more into the taper portion 4 of the base circle portion 3 of the cam piece 1, so that a more stable coupling force in the axial direction and the circumferential direction can be obtained.

Next, a method of manufacturing the assembled camshaft of the present invention will be described with reference to FIGS. FIG. 5 is a sectional view showing an outline of bulge processing, FIG. 6 is an enlarged sectional view showing a state before bulge forming, and FIG. 7 is an enlarged sectional view showing a state after bulge forming. In FIG. 5, reference numeral 20 denotes a main body of the bulge processing apparatus, and an upper die 21 and a lower die 22 which are molding dies are attached to the main body 20. Between the upper mold 21 and the lower mold 22, an assembled camshaft in which the cam piece 1, the journal piece 23 and the like are externally inserted on the outer peripheral surface of the material tube 10 is arranged. This material tube 10
Punches 24 are inserted into both ends of the material tube 10 to keep the inside of the material tube 10 in a sealed state. A pressure fluid of a predetermined size is introduced into the material tube 10 from one side of the punch 24.

The upper half of the blank tube 10 in FIG. 5 and FIG.
Shows the state before bulge forming, and is the material pipe 1 in FIG.
The lower half of FIG. 0 and FIG. 7 show the state after bulging. As shown in FIGS. 5 to 7, when a pressure fluid is introduced into the material tube 10, the material tube 10 is bulged and deformed, and the material tube 10 causes the taper portion 4 of the base circle portion 3 of the cam piece 1.
The cam piece 1 and the material pipe 10 are coupled by a stable predetermined coupling force. Also at this time,
The journal piece 23 and the like are also joined to the material tube 10 by a predetermined joining force.

In the embodiment of the present invention configured as described above, the base circle portion 3 of the cam piece 1 and the taper portion 4 are provided.
The taper portion 4 of the base circle portion 3 of the cam piece 1 is formed at the time of bulge forming because
The material pipe 10 and the material pipe 10 are connected so as to bite into each other. Therefore, in the present invention, a stable coupling force in the axial direction and the circumferential direction can be obtained between the cam piece 1 and the material pipe 10.

Further, the cam piece 1 only needs to form a taper portion on the base circle portion 3, and therefore the cam piece 1 is structurally simple and easy to form.

[0018]

As described above, according to the present invention, a stable coupling force in the axial direction and the circumferential direction can be obtained between the cam piece and the material pipe, and the structure is simple, so that the molding is easy. Become.

[Brief description of drawings]

FIG. 1 is a front view showing a cam piece before bulging.

FIG. 2 is a cross-sectional view taken along the line AA of FIG.

FIG. 3 is a cross-sectional view of the assembled camshaft showing a state in which the cam piece and the material pipe are joined after performing the bulging process.

FIG. 4 is a sectional view showing a cam piece used in another embodiment of the present invention.

FIG. 5 is a cross-sectional view showing an outline of bulge processing.

FIG. 6 is an enlarged cross-sectional view showing a state before bulge forming.

FIG. 7 is an enlarged cross-sectional view showing a state after bulge forming.

[Explanation of symbols]

 1 Cam Piece 2 Top Part 3 Base Circle Part 4 Tapered Part 5 Shaft Hole 6 Inner Surface 10 Material Pipe

Claims (3)

[Claims] 1. An assembled camshaft comprising a cam piece having a top portion, a base circle portion, and an inner peripheral surface of a shaft hole, and a material pipe inserted into the shaft hole of the cam piece, wherein the base circle of the cam piece is provided. The portion is formed so as to become narrower downward, and a pressure fluid having a predetermined pressure is introduced into the material pipe to bulge and deform the material pipe, whereby the cam piece and the material pipe are separated. An assembled camshaft, characterized in that they are integrally coupled. 2. The assembled camshaft according to claim 1, wherein a tapered portion is formed on a base circle portion of the cam piece, and a side surface of the tapered portion is inclined at a predetermined angle. 3. A cam piece having a top portion, a base circle portion, and an inner peripheral surface of a shaft hole is provided, and the base circle portion of the cam piece is formed so as to become narrower toward the lower side. The material pipe is inserted into the hole, and a pressure fluid having a predetermined pressure is introduced into the material pipe to bulge and deform the material pipe, thereby integrally connecting the cam piece and the material pipe. A method for manufacturing an assembled camshaft, comprising: