JP3429577B2 - Method for manufacturing assembled camshaft of internal combustion engine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a camshaft called a prefabricated type used in an internal combustion engine such as a gasoline engine or a diesel engine.

[0002]

2. Description of the Related Art As is well known, in an internal combustion engine such as a gasoline engine or a diesel engine, a cam mounted on a cam shaft which works with a main shaft (crank shaft) of the engine causes a timing of intake and exhaust of each cylinder. Are in control. An example of the camshaft is shown in FIG.

FIG. 5 shows a camshaft of a 6-cylinder engine.
A gear attached to one end rotates in conjunction with the main shaft of the engine. 1 is a metal tube, 2 is a cam piece corresponding to each cylinder a to f of the engine, 2a is a journal piece that supports rotation of the cam shaft, 2b is a thrust piece that supports axial positioning and thrust of the cam shaft, and 2c is The oil seal piece 2d is an end piece that closes the end of the pipe. Hereinafter, 2 and 2a to 2d are referred to as an assembly member for the metal pipe 1, and will be described as an example of a cam piece.

Conventionally, the camshaft has been integrally manufactured by forging or casting, and the shaft portion has a solid structure.
Along with the reduction in weight and speed of engines, "assembled camshafts" having a structure in which cams and other members are attached to hollow metal pipes have been developed and are in widespread use. As an example thereof, a method of attaching a member to a metal tube disclosed in Japanese Patent Laid-Open No. 5-10340 will be described with reference to FIGS.

FIG. 6 is a front view showing an example of the material of the shaft.
A circumferential or spiral ridge 14 is formed at a predetermined position of the metal tube 1 by bulging with a knurl (a tool that presses a cylindrical work with a lathe or the like to make unevenness).
On the other hand, FIG. 7 is a side view of the cam piece 2 assembled to the metal tube 1. The mounting hole provided in the cam piece 2 is formed by replacing the arc surface 25a at several places with the chord surface 25b. The diameter of the arc surface 25a is larger than that of the raised portion 11 of the metal tube 1, The surface distance between the surfaces 25b is smaller than the outer diameter of the raised portion 14 but larger than the outer diameter of the general portion of the metal tube 1. Therefore, when the cam piece 2 is press-fitted to the position of the raised portion 14 of the metal tube 1, one or both of the chord surface 25b and the raised portion 14 is plastically deformed, so that the cam piece 2 is assembled at a predetermined position. Figure 8 shows the state after press fitting
Shown in.

A member such as a cam piece attached to the metal pipe 1 has an outer portion in a follower-to-point contact in the case of a cam, and a bearing or a sliding contact in the case of a journal, so that mechanical strength and wear resistance. In addition, it is preferable that the inner portion to be attached to the shaft is made of a soft material that is easily plastically deformed, because press-fitting is easy and there is no risk of cracking, while accuracy of the finished dimensions is required. Therefore, Japanese Patent Application Laid-Open No. 5-60203 discloses a structure in which the outer portion and the inner portion are made of different members made of different materials. This is shown in FIGS.

FIG. 9 is a side view showing an example of a cam piece in which the outer portion and the inner portion are made of different members made of different materials. The cam piece 2 includes an inner piece 21 of an inner member fitted to a shaft and a cam profile. The inner piece 21 is made of low carbon steel, and the outer piece 22 is made of a sintered alloy. Both are heated in a sintering furnace and integrated by diffusion bonding. FIG. 10 shows a state in which this is fitted to the metal tube 1.

By the way, since the outer peripheral surface of the cam piece is in sliding contact or sliding contact with a member usually called a cam follower as described above, it is necessary to lubricate the contact surface. In the assembly type camshaft, by utilizing the fact that the camshaft itself is hollow with a metal tube, an oil hole reaching the inside of the metal tube inside is provided in the cam piece, and from the inside of the metal tube through the oil hole the outer circumference of the cam Lubricating oil is supplied to the surface.

However, as described above, since the shape and size of the mounting hole of the cam piece are not the same as the outer diameter of the metal pipe, the lubricating oil exudes or leaks from the joint between the cam piece of the oil hole and the metal pipe. The required amount does not reach the outer peripheral surface,
There was a risk of insufficient lubrication. Therefore, JP-A-5
-96409 discloses that a pipe material made of a synthetic resin or a soft metal is press-fitted through an oil hole of a metal tube and an oil hole of a cam piece. This will be described with reference to FIG.

Reference numeral 12 is a pilot hole machined in the metal tube 1, 23 is a pilot hole machined in the cam piece 2, and 33 is a pipe material inserted through these and press-fitted. The metal pipe 1 and the cam piece 2 are machined with radial pilot holes 12 and 23, respectively.
After assembling, the seamless pipe member 33 is press-fitted by inserting these pilot holes 12 and 23. The pilot hole 12,
Each of the processes of 23 may be performed in advance or may be processed after being assembled. When the pilot hole is processed in advance,
Although the centers of the lower holes 12 and 23 may not necessarily coincide with each other depending on the assembled state, since the pipe material 33 is a flexible material such as synthetic resin or soft metal, it can be fitted into them and press-fitted. Since the pipe material 33 passes seamlessly from the hollow portion 13 of the metal pipe 1 to the sliding surface of the outer periphery of the assembly member 2, there is no oil leakage in the intermediate gap portion g and good lubrication can be performed. .

However, in this oil supply structure, not only is there a risk that the pipe material 33 will fall off due to the rotation of the camshaft, and oil will leak from the gap between the pilot hole and the pipe material, but some accuracy will be required for drilling the pilot hole. Since it is required, there is a problem that the cost becomes high.

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to realize a method of manufacturing a camshaft which is low in cost and has no fear of oil leakage.

[0013]

According to the present invention as set forth in claim 1, a raised portion is formed on the outer peripheral surface of a metal tube, and a circular hole having an inner diameter portion slightly smaller than the outer diameter of the raised portion is provided. In an assembling camshaft for an internal combustion engine in which the circular hole is press-fitted into the raised portion of the metal pipe to assemble the assembly member, the assembly member in which a radial pilot hole is previously machined is
After assembling the genus tube, the resin material from the cured filled into the lower hole of that, in the resin material, the internal combustion engine, characterized in that processing the radial oil hole penetrating to the metal tube Is a method for manufacturing a prefabricated camshaft.

According to a second aspect of the present invention, the assembly member has an inner piece having a circular hole having an inner diameter portion slightly smaller than the outer diameter of the raised portion, and an outer piece joined to the outer side of the inner piece. Consists of the inner
A method for producing a prefabricated camshaft of an internal combustion engine according to the size Kushida claim 1 than the diameter of the lower hole diameter of the lower hole is formed in the outer piece to form the piece.

[0015]

[0016]

[0017]

[Operation] According to the present invention, in the assembly type camshaft of an internal combustion engine, a pre-hole in the radial direction is machined in the assembly member to be mounted, and the pre-hole is filled with a resin material and cured, and then the resin Since a radial oil hole that penetrates to the metal pipe is formed near the center of the material, there is no gap that causes oil leakage on the inner surface and the periphery of the oil hole, and reliable lubrication on the outer peripheral surface of the assembly member. In addition, it does not require strict precision to process the pilot hole or oil hole, it can be processed at low cost, and it does not peel off or fall off because the resin material penetrates into the gap and hardens. .

[0018]

【Example】

Example 1 A first example of the present invention is shown in FIGS. FIG. 1 is a cross-sectional view of the camshaft cut in a direction perpendicular to the axis, FIG. 2 is a partial cross-sectional view in the axial direction taken along the line AA, and FIG. 3 is a main-part cross-sectional view showing a processing procedure of this embodiment. A metal tube, 13 is its hollow portion, 2 is a cam piece which is an example of an assembly member,
Reference numeral 21 is the inner piece, 22 is the outer piece, 31 is a resin material, and 32 is an oil hole.

The camshaft of this embodiment is an assembling type camshaft in which the inner part and the outer part of the cam piece 2 are formed by separate members like the one shown in FIG. Lower holes 23 and 24 are formed at the positions where the oil holes are provided, respectively. The inner piece 21 and the outer piece 22 in which the pilot holes 23 and 24 are processed in advance are heated and integrated, and then press-fitted into the raised portion 14 of the metal tube 1 to be assembled. This state is shown in FIG. The point to be noted here is that the metal tube 1 is not pre-drilled, and the inner piece 21 and the outer piece 22 have holes 23 and 24,
The former has a slightly larger diameter.

Next, as shown in FIG. 3 (b), the lower holes 23 and 24 are filled with the resin material 31. It is preferable that the resin material 31 has high fluidity so that the resin material 31 can permeate well into the surface of the metal tube 1 and the gap g between the metal tube 1 and be filled according to the shape of the pilot holes 23 and 24. The shorter the better. After hardening, it is also important that the inner surfaces of the pilot holes 23, 24 are well adhered, and oil stains and the like inside the pilot holes should be thoroughly cleaned before filling. Examples of the resin include epoxy compound resin, photocurable resin, and silicone resin.

After the resin material 31 is cured, as shown in FIG.
A radial oil hole 32 penetrating to the metal pipe 1 is formed near the center of the resin material 31. Thus, as shown in FIGS. 1 and 2, an oil hole 32 reaching the outer peripheral surface of the assembly member 2 from the hollow portion 13 of the metal tube 1 is formed, and the inner surface of the oil hole 32 is made of resin. Since there is no gap for oil leakage because it is formed by filling and hardening it, and there is no gap on the back surface of the resin material 31, the lubricating oil sent from the hollow part 13 does not leak on the way. Is supplied to the outer peripheral surface of the assembly member 2 which is a sliding surface, and the diameter of the pilot hole 23 is slightly larger than the diameter of the pilot hole 24 even if the adhesion between the resin material 31 and the cam piece is peeled off. 31 does not come out.

Second Embodiment A second embodiment of the present invention is shown in FIG. In this embodiment, the inner part and the outer part of the cam piece 2 are not composed of separate members,
It is an assembled camshaft which is an integral member, and is otherwise the same as the first embodiment. The cam piece 2 in which the pilot hole 23 is processed in advance is press-fitted into the raised portion 14 of the metal tube 1 to be assembled, and the resin material 31 is filled in the pilot hole 23. After the resin material 31 is hardened, an oil hole is penetrated through to the metal pipe 1 at almost the center of the resin material 31.
By processing 32, an oil hole 32 that reaches the outer peripheral surface of the assembly member 2 from the hollow portion 13 of the metal tube 1 is formed. As in the first embodiment, since the inner surface of the oil hole 32 is formed by filling and hardening the resin, there is no space for oil leakage, and there is no space on the back surface of the resin material 31. The lubricating oil sent from the hollow portion 13 is supplied to the outer peripheral surface of the assembly member 2, which is a sliding surface, without leaking on the way. At the time of filling, the resin material 31 penetrates into the surface of the metal tube 1 and the gap g between the metal tube 1 and hardens, so that these parts become caught and the resin does not come out.

Further, the prepared hole does not require strict accuracy in terms of position and diameter, and the oil hole to be machined later may be within the range of the resin material, so that there is no problem in a slight positional deviation.
Further, the metal tube can be processed at a low cost because it is not necessary to process the prepared hole in advance.

[0024]

According to the present invention, a method for manufacturing a camshaft is realized which is capable of performing reliable lubrication without oil leakage, is low in cost, and is free from deterioration such as dropping of a resin material. Produce the effect.

[Brief description of drawings]

FIG. 1 is a sectional view of a camshaft showing a first embodiment of the present invention.

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

FIG. 3 is a cross-sectional view of a main part showing a processing procedure of the cam shaft according to the first embodiment of the present invention.

FIG. 4 is a sectional view of a camshaft showing a second embodiment of the present invention.

FIG. 5 is a front view showing an example of a camshaft according to the present invention.

FIG. 6 is a front view of a part of a metal tube showing a conventional technique.

FIG. 7 is a side view of a cam piece showing a conventional technique.

8 is a front view showing a state where the cam piece of FIG. 7 is press-fitted into a cam shaft.

FIG. 9 is a side view of a cam piece showing another conventional technique.

10 is a front view showing a state where the cam piece of FIG. 9 is press-fitted into a cam shaft.

FIG. 11 is a cross-sectional view of a camshaft showing still another conventional technique.

[Explanation of symbols]

1 metal tube 2 Cam piece (assembly member) 12 Pilot hole 13 Hollow part 14 Raised part 21 Inner piece (inner member) 22 Outer piece (outer member) 23, 24 pilot hole 25a circular surface 25b chord 31 Resin material 32 oil hole 33 Pipe material

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-350306 (JP, A) Actually open 5-96409 (JP, U) Actually open 60-121552 (JP, U) Actually open 60- 28651 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) F01L 1/04 F01M 1/06 F01M 9/10

Claims (2)

(57) [Claims] 1. A mounting member having a circular hole having an inner diameter portion slightly smaller than an outer diameter of the raised portion, the raised member being formed on the outer peripheral surface of the metal pipe. In an assembly type camshaft of an internal combustion engine that is press-fitted into the assembly, after assembling the assembly member in which the radial pilot hole is processed in advance to the metal pipe, and filling the pilot hole with the resin material and hardening it. A method for manufacturing a prefabricated camshaft for an internal combustion engine, characterized in that an oil hole in a radial direction that penetrates to the metal pipe is formed in the resin material. Wherein assembling member, and the inner piece <br/> having circular holes having a slightly smaller inner diameter than the outer diameter of the raised portion is joined to the outer side of the inner piece Autapi
The method for manufacturing a prefabricated camshaft for an internal combustion engine according to claim 1 , wherein the diameter of the pilot hole formed in the inner piece is larger than the diameter of the pilot hole formed in the outer piece .