JP2001355709A - Cam piece of assembling cam shaft and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a earn piece by fine blanking work capable of allowing the molding accuracy and the manufacturing cost to be compatible with each other without increasing edge sagging of the die. SOLUTION: This cam piece 9 is composed of two divided bodies 11 and 13 obtained by dividing an axial width necessary as the cam piece 9 into two. The two divided bodies 11 and 13 are respectively blanked by fine blanking, and then bonded and fixed by a hollow caulking material 17. The cam piece 9 obtained by integrating the divided bodies 11 and 13 is fixed to a metallic pipe 15 by inserting the pipe 15 into shaft insertion holes 11a and 13a and enlarging the pipe by applying the water pressure into the pipe 15, whereby a cam shaft is assembled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cam piece of an assembled camshaft in which a shaft main body is inserted into a shaft insertion hole of a cam piece and both are fixed to each other, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In an internal combustion engine such as a gasoline engine, there is an assembling camshaft which rotates in conjunction with a crankshaft and controls opening and closing timings of intake and exhaust valves. This assembled camshaft is
The shaft body is formed of a metal pipe, and this pipe is inserted into the shaft insertion hole 3 of the cam piece 1 as shown in FIG.
The metal tube is fixed by press-fitting, or after insertion, a water pressure or the like is applied to the inside of the metal tube to expand the tube so that the two are fixed to each other.

[0003] By forming the shaft body as a hollow pipe, the conventional cam piece portion and the shaft body portion are integrally formed to reduce the weight of the shaft body portion as compared with a solid shaft body, thereby reducing the engine weight and increasing the speed of the engine. (For example, JP-A-6-341304, JP-A-8-341304)
No. 93415).

The cam piece 1 of such an assembling camshaft is mostly manufactured by hot or cold forging, and in some cases, a cam piece using a sintered material is also employed.

[0005]

However, when the cam piece is manufactured by hot or cold forging, the positioning accuracy when assembling the cam piece to the shaft body is taken into consideration because the forming accuracy is poor at about ± 0.2 mm. Then
It is necessary to increase the radial length L shown in FIG. 4 to secure a sufficiently large machining allowance when performing finishing after assembling. Since the cam surface 5 of the cam piece 1 has abrasion resistance, the machinability is not good. Therefore, when the finishing machining allowance is large, the finishing machining time becomes longer and the tool cost is increased. There's a problem.

On the other hand, when a cam piece is manufactured from a sintered material, the molding accuracy is as good as about ± 0.02 mm.
In order to secure the wear resistance and pitting resistance of the cam surface 5 of the cam piece, it is necessary to use an alloy containing chromium (Cr) or the like and to increase the sintering density, thereby increasing the manufacturing cost. .

As a method for achieving both the above-mentioned molding accuracy and manufacturing cost, fine blanking in which the cam piece 1 is formed by punching may be used. The necessary thickness H (axial width) of the cam piece 1 is 11 m.
Blanking the equivalent of m at one time would increase the mold droop 7 and necessitate a review of the tolerance width of the cam piece 1 and the mold life, mold toughness of mold components, and mold breakage due to insufficient rigidity There is a problem of doing.

Accordingly, an object of the present invention is to manufacture a cam piece by punching without compromising the shape of the mold and achieving both high molding accuracy and high manufacturing cost.

[0009]

In order to achieve the above object, according to the present invention, there is provided a cam piece of an assembling camshaft in which a shaft main body is inserted into a shaft insertion hole of the cam piece and both are fixed to each other. The required axial direction width is appropriately divided into a plurality to form a plurality of divided bodies, and the plurality of divided bodies are formed by punching, and the divided bodies are joined and fixed to each other. .

According to the cam piece of the assembling camshaft having such a configuration, the axial width required for the cam piece is appropriately divided into a plurality of parts to constitute a plurality of divided bodies, thereby making it possible to manufacture each divided body. The punching width is smaller and the mold is smaller.

According to a second aspect of the present invention, in the configuration of the first aspect of the present invention, each of the divided bodies is fixedly joined by inserting a caulking material into a caulking hole.

According to the above configuration, the caulking material is inserted into the caulking hole of each divided body and caulked, whereby the plurality of divided bodies are joined and fixed to each other to form one cam piece.

According to a third aspect of the present invention, in the configuration of the second aspect, the caulking material is made of a hollow material.

According to the above configuration, the hollow portion of the caulking material contributes to the weight reduction of the entire cam piece.

According to a fourth aspect of the present invention, in the configuration of the second or third aspect, the caulking material is made of a material that is lighter than the divided body that is the base material.

According to the above configuration, the weight of the caulking material fitted into the caulking hole contributes to the weight reduction of the entire cam piece.

According to a fifth aspect of the present invention, in the configuration of any one of the first to fourth aspects, the shaft main body is a hollow pipe, and the pipe is expanded and tightly fixed to the inner surface of the shaft insertion hole. Wherein the inner surface of the shaft insertion hole has an inclined surface that is inclined with respect to the axial direction.

According to the above configuration, by expanding the hollow pipe in a state where it is inserted into the shaft insertion hole of the cam piece, the outer peripheral surface of the pipe is tightly fixed to the inner surface of the shaft insertion hole of the cam piece. At this time, the shaft insertion hole is
The inclined surface with respect to the axial direction increases the contact area between the outer peripheral surface of the expanded pipe and the inner surface of the shaft insertion hole.

According to a sixth aspect of the present invention, in the configuration of the fifth aspect of the present invention, the inclined surface is formed by a tapered surface having a shaft insertion hole whose diameter dimension changes along the axial direction.

According to the above structure, the hollow pipe is expanded while being inserted into the shaft insertion hole of the cam piece, whereby the outer peripheral surface of the pipe is tightly fixed to the tapered surface of the inner surface of the shaft insertion hole of the cam piece.

According to a seventh aspect of the present invention, in the configuration of any one of the first to sixth aspects of the present invention, the plurality of divided bodies have different cam surfaces from each other.

According to the above configuration, it is possible to obtain a cam piece provided with portions having different cam surfaces.

The invention according to claim 8 is a method for manufacturing a cam piece of an assembled camshaft in which the shaft body is inserted into the shaft insertion hole of the cam piece and the two are fixed to each other. Then, a plurality of divided bodies are formed, and the plurality of divided bodies are formed by punching, and the divided bodies are joined and fixed in a state where the shaft insertion holes are aligned with each other.

According to the above-described method of manufacturing a cam piece, the axial width required for the cam piece is appropriately divided into a plurality of pieces, so that the punching width of each of the divided pieces is reduced, thereby reducing mold drooping.

[0025]

According to the first aspect of the present invention, the axial width required for the cam piece is appropriately divided into a plurality of parts to form a plurality of divided bodies. Low manufacturing cost.Easy punching and reduced mold drooping.Therefore, there is no need to reconsider the tolerance of cam pieces.Die life, toughness of mold components, and prevention of mold breakage due to insufficient rigidity. Can be.

According to the second aspect of the present invention, since the caulking material is inserted into the caulking hole between the divided bodies, the plurality of divided bodies can be securely joined and fixed.

According to the third aspect of the present invention, the caulking material is made of a hollow material.
The weight of the entire cam piece can be reduced.

According to the fourth aspect of the present invention, since the caulking material is made lighter than the divided body as the base material, the weight of the entire cam piece can be reduced.

According to the fifth aspect of the present invention, the shaft body is a hollow pipe, and the shaft insertion hole has an inclined surface inclined with respect to the axial direction. By expanding the pipe while inserted into the shaft insertion hole, the contact area between the outer peripheral surface of the expanded pipe and the shaft insertion hole of the cam piece becomes large, thereby improving the torsional strength of the cam piece, and the like. The bonding strength is improved.

According to the sixth aspect of the present invention, since the inclined surface is formed by the tapered surface in which the diameter of the shaft insertion hole changes along the axial direction, the hollow pipe is connected to the shaft insertion hole of the cam piece. By expanding the pipe in the inserted state, the contact area between the outer peripheral surface of the expanded pipe and the shaft insertion hole of the cam piece increases, thereby improving the torsional strength of the cam piece and improving the coupling strength between the cam piece and the shaft body. I do.

According to the seventh aspect of the present invention, since the plurality of divided bodies have different cam surfaces from each other, by joining these divided bodies together, a cam piece having a portion having a cam surface different from each other can be obtained. Obtainable.

According to the eighth aspect of the present invention, a plurality of divided bodies are formed by appropriately dividing the axial width required as a cam piece into a plurality of divided bodies, and each of the plurality of divided bodies is formed by punching. Since the divided bodies are joined to each other with the shaft insertion holes aligned, it is easy to perform punching work with good molding accuracy and low manufacturing cost for each of the divided bodies, resulting in a smaller mold droop. There is no need to review the tolerance width of the cam piece, and it is also possible to prevent mold breakage due to lack of mold life and toughness and rigidity of mold components.

[0033]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a cam piece 9 of an assembled camshaft according to a first embodiment of the present invention.
FIG. 3A is a perspective view of divided bodies 11 and 13 formed by dividing an axial width (thickness) required of the cam piece 9 into two parts, and FIG. FIG. 3C is a side view of the cam piece 9 in which the two divided bodies 11 and 13 are joined together.

Each of the divided bodies 11 and 13 is made of a commonly used blanking material (eg, SAPH400).
Each thickness is about 6 mm, and each is punched by fine blanking. At the time of this fine blanking, shaft insertion holes 11a and 13a into which a metal pipe 15 as a shaft main body is inserted as shown by a two-dot chain line in FIG.
b and 13b are processed simultaneously or separately with the blanking processing of the outer shape.

Both divided bodies 11 and 13 subjected to blanking
While aligning the shaft insertion holes 11a and 13a with each other and aligning the caulking holes 11b and 13b with each other,
The caulking material 17 is fitted into the caulking holes 11b and 13b in a state of being overlapped with each other, and caulked and fixed. The caulking material 17 is a hollow cylindrical member. Therefore, the caulking material 17 is reduced in weight and the cam piece 9 itself is also reduced in weight because of the hollow portion.

The caulking material 17 is replaced with a hollow material,
By using a material that is lighter than the material of the divided bodies 11 and 13 as the base material, the weight of the cam piece 9 can be reduced. In addition, if the caulking function is sufficiently ensured, the caulking material 17 may be a material lighter than the material of the divided bodies 11 and 13 and may be a hollow material.

The shaft insertion holes 11a, 13 of the pipe 15
a, the outer diameter of the pipe 15 is
After slightly reducing the inner diameters of the pipes 15 and 13a, the inside of the pipe 15 inserted into the shaft insertion holes 11a and 13a is
The tube is expanded by applying water pressure or hydraulic pressure, and closely fixed. This fixing is not limited to the method of expanding the pipe by hydraulic or hydraulic pressure, and the pipe 15 may be pressed into the shaft insertion holes 11a and 13a.

The above-mentioned cam piece 9 is formed by punching two divided bodies 11 and 13 each having a half dimension of the axial width H required for the cam piece 9 with fine blanking which is advantageous in terms of molding accuracy and manufacturing cost. Therefore, even if blanking is performed at one time, the shape does not increase. For this reason, there is no need to review the tolerance width of the cam piece 9, and the mold life and the mold breakage due to insufficient toughness and rigidity of the mold components are prevented.

FIG. 2 is a side view of a cam piece 19 showing a second embodiment of the present invention. This cam piece 19
The shaft insertion holes 21a and 23a formed in the two divided bodies 21 and 23 have tapered surfaces as inclined surfaces whose diameters change along the axial direction. The processing of the tapered surface may be post-processing using a tapered punch after the normal straight blanking processing. In each of the divided bodies 21 and 23 having such a tapered surface, the side surfaces on the side where the inner diameter of the shaft insertion holes 21a and 23a are small are joined.

If the shaft insertion holes 21a and 23a have tapered surfaces, when the metal pipe 25 is inserted into the shaft insertion holes 21a and 23a and then expanded by water pressure or the like, the pipe 25 and the shaft insertion holes 21a and 23a are removed. The contact area between the pipe 25 and the cam piece 19 is improved, for example, the contact area with the pipe 23 is larger than that on the straight surface, and the torsion strength of the pipe 25 is improved. Pipe 2 in this case
5 indicates the outer diameter of the shaft insertion holes 21a, 23a before the pipe expansion.
Slightly smaller than the minimum inside diameter.

Since the shaft insertion holes 21a and 23a of the integral cam piece 19 have the smallest diameter at the center in the axial direction, the joint strength between the pipe 25 and the cam piece 19 in the axial direction is small. Is more improved.

Reference numeral 27 denotes a hollow caulking material, which is caulked into caulking holes 21b and 23b formed on the divided bodies 21 and 23, respectively, as in FIG. 21 and 23 are joined and fixed.

FIG. 3 shows a cam piece 29 according to a third embodiment of the present invention. FIG. 3A shows that the cam piece 29 requires three axial widths (thicknesses). FIG. 3B is a perspective view of the divided bodies 31, 33, and 35 formed by dividing, FIG. 3B is a perspective view of a state in which three divided bodies 31, 33, and 35 are joined and fixed to each other, and FIG. Divided body 3
It is a side view of the cam piece 29 which mutually joined 1,33,35.

Also in the cam piece 29 of this embodiment, the thickness of each of the divided bodies 31, 33, and 35 is about 6 mm.
Even if 1, 33 and 35 are punched at once,
The mold does not grow.

Of the three divided bodies 31, 33 and 35 described above, the central divided body 33 is the upper and lower two divided bodies 31, 33 and 35.
The shape of the cam surface is different from that of the cam piece 35. Thus, by dividing the cam piece 29 into a plurality of pieces, it is possible to obtain a cam piece 29 having a cam surface having a different shape.

Reference numerals 31a, 33a and 35a are shaft insertion holes into which metal pipes 37 are inserted.
Reference numeral 39 denotes a hollow caulking material. The caulking material 39 is fitted into caulking holes 31b, 33b, and 35b formed in the divided bodies 31, 33, and 35, and caulked to obtain the divided bodies 31, 33, and 35. 35 are mutually fixed.

[Brief description of the drawings]

FIG. 1 shows a cam piece of an assembled camshaft according to a first embodiment of the present invention. FIG. 1 (a) divides a required axial width (thickness) of the cam piece into two. FIG. 2B is a perspective view of the divided body configured as described above, FIG. 2B is a perspective view of a state in which the two divided bodies are joined, and FIG. 1C is a side view of a cam piece in which the two divided bodies are joined.

FIG. 2 is a side view of a cam piece of an assembled camshaft according to a second embodiment of the present invention.

FIG. 3 shows a cam piece of an assembled camshaft according to a third embodiment of the present invention. FIG. 3 (a) divides the required axial width (thickness) of the cam piece into three. FIG. 4B is a perspective view of the divided body configured as described above, FIG. 4B is a perspective view of a state in which the three divided bodies are joined, and FIG. 4C is a side view of a cam piece in which the three divided bodies are joined.

4A and 4B show a cam piece of an assembled camshaft according to a conventional example, wherein FIG. 4A is a perspective view and FIG. 4B is a side view.

[Explanation of symbols]

9, 19, 29 Cam pieces 11a, 13a, 21a, 23a, 31a, 33a, 3
5a Shaft insertion hole 11, 13, 21, 23, 31, 33, 35 Split body 15, 25, 37 Pipe (shaft body) 11b, 13b, 21b, 23b, 31b, 33b, 3
5b Crimp hole 17, 27, 39 Crimp material

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Kimio Nishimura 2nd Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa F-term in Nissan Motor Co., Ltd. (reference) 3G016 AA19 CA12 CA32 CA45 CA52 FA06 FA08 FA35 3J030 EA01 EA15 EB09 EC03 EC07

Claims (8)

[Claims] In a cam piece of an assembling camshaft in which a shaft main body is inserted into a shaft insertion hole of the cam piece and the two are fixed to each other, an axial width required for the cam piece is appropriately divided into a plurality of pieces to form a plurality of divided bodies. The plurality of divided bodies are formed by punching, and the divided bodies are joined and fixed to each other. 2. A cam piece for an assembled camshaft according to claim 1, wherein a caulking material is fitted into the caulking hole and joined and fixed to each other. 3. The cam piece for an assembled camshaft according to claim 2, wherein the caulking material is made of a hollow material. 4. The cam piece for an assembled camshaft according to claim 2, wherein the caulking material is made of a material that is lighter than the divided body that is the base material. 5. The shaft body is a hollow pipe,
The pipe is expanded so as to be closely fixed to an inner surface of a shaft insertion hole, and the inner surface of the shaft insertion hole is provided with an inclined surface inclined with respect to an axial direction. 5. The cam piece of the assembled camshaft according to any one of items 4 to 4. 6. The cam piece according to claim 5, wherein the inclined surface is formed by a tapered surface in which the shaft insertion hole has a diameter that varies along the axial direction. 7. The cam piece for an assembled camshaft according to claim 1, wherein the plurality of divided bodies have different cam surfaces. 8. A method of manufacturing a cam piece for an assembled camshaft, wherein a shaft body is inserted into a shaft insertion hole of the cam piece and the two are fixed to each other. A cam piece for an assembling camshaft, wherein the plurality of divided bodies are formed by punching, and the divided bodies are joined and fixed in a state where the shaft insertion holes are aligned with each other. Production method.