JPH07158416A - Tappet for internal combustion engine and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a compact, lightweight tappet while enhancing bonding strength between a cylindrical member and a cam receiving member. CONSTITUTION:The ring piece 3 of a cam receiving member 2 made of wear resistant metallic material is press-fitted while shearing the inner peripheral surface of the opening end of a cylindrical member 1. An oxide film or the like formed at the press-fitted place of the cylindrical member 1 is thereby removed, and both members 1, 2 are rigidly connected by intermetallic bonding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tappet used for a valve train of an internal combustion engine and a method for manufacturing the tappet.

[0002]

2. Description of the Related Art In recent years, for the purpose of reducing the inertial mass of a valve train, tappets (valve lifters) used in direct drive valve trains are manufactured from light metals, that is, aluminum alloys, etc., instead of ordinary iron-based materials. There is more to do.

Since such an aluminum alloy tappet has less abrasion resistance than iron-based materials, as shown in FIG. 7, a cam (not shown) of the tappet body (01) is in sliding contact. Recesses (02) and (03) are formed at the center of the inner bottom surface where the shaft end of the engine valve (not shown) comes into contact with the upper surface, and these recesses (02) and (03) are made of iron-based hard material. Generally, the shim (04) and the chip (05) are attached and used.

[0004]

In the conventional tappet as described above, the annular receiving portion (06) for holding the shim (04) is continuously provided upward on the upper surface of the tappet body (01) to form a recess. Since it is necessary to form the (02) and the strength of the annular receiving portion (06) needs to be relatively large in terms of strength, there is a problem that the total length and outer diameter of the tappet become large.

In this case, not only the weight of the tappet is increased, but also the size of the guide hole of the cylinder head into which the tappet is fitted becomes large, and the degree of freedom in design is limited. Further, since the upper wall (07) is indispensable for the tappet body (01), there is a limit to weight reduction.

In order to deal with these problems, a cylindrical member fitted into a guide hole of a cylinder head and a cam receiving member with which a cam is in sliding contact are molded separately from aluminum alloy and iron-based metal. However, it is also conceivable that they are pressed into each other, that is, they are connected to each other by an interference fit.

However, there is a problem in that a sufficient bond strength cannot be obtained by ordinary press-fitting. This is because aluminum alloys are extremely active and form a strong oxide film in the air, so even if iron-based metals of different materials are simply pressed in, the oxide film will affect and a large bonding force will not be obtained. Because.

Moreover, since the bond strength by press fitting is mainly dependent on the yield strength of aluminum alloy or the like, in order to obtain a large bond strength, the press fit margin (length) needs to be relatively long. However, in this case, the total length of the cam receiving member becomes long, which goes against weight reduction.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to increase the coupling strength between the cylindrical member and the cam receiving member and to reduce the size and weight of the internal combustion engine with relatively simple means. It is an object to provide a tappet for an engine and a manufacturing method thereof.

[0010]

In order to achieve the above object, a tappet according to the present invention is a cam receiver formed of a wear-resistant metal material in a disk shape at one open end of a cylindrical member made of a light metal material. A member is press-fitted.

In the tappet, a cylindrical member made of a light metal material is formed into a disc shape at one open end thereof, and an annular piece having a required length facing the plate thickness direction is continuously provided on one surface of the disc member. The annular piece in the cam receiving member made of a wear-resistant metal material can be manufactured by press-fitting while shearing either one of the inner and outer peripheral surfaces of the opening end. At the time of production, it is preferable to form a blade for shearing on the peripheral edge of the annular piece that is in contact with the cylindrical member.

In the case where the annular piece is press-fitted to the inner peripheral surface side of the cylindrical member, the outer diameter of the annular piece is made different so that the press-fitting direction side gradually becomes smaller, and the portion where the different outer diameters intersect with each other. It is preferable to form an annular groove in the.

[0013]

[Operation] By press-fitting the cam receiving member made of the wear-resistant metal material into one opening end of the cylindrical member made of the light metal material,
The overall length is shorter and the weight is lighter than that of conventional tappets.

In manufacturing, the annular piece of the cam receiving member is
When the inner and outer peripheral surfaces of the open end of the cylindrical member are press-fitted while being sheared, the oxide film formed at the press-fitted portion of the cylindrical member is removed, so that both members are firmly bonded by intermetallic bonding.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of a tappet (T) of the present invention, which comprises a cylindrical member (1) made of a light metal material such as an aluminum alloy or a magnesium alloy, and a cast iron, alloy cast iron, carburized steel, etc. Cam receiving member made of abradable metal material
It consists of (2). The cam receiving member (2) is a cylindrical member.
It has a disk shape with a diameter almost equal to the outer diameter of (1), and a cylindrical pressing member where the shaft end of an engine valve (not shown) abuts on the lower surface of the disk shape near the outer peripheral edge and in the center. Part (4)
Each of them is arranged vertically downward facing the plate thickness direction.
(5) is a relief groove for avoiding stress concentration on the corners.

The cylindrical member (1) and the cam receiving member (2) are integrally connected by press-fitting the annular piece (3) onto the inner peripheral surface of the upper end portion of the cylindrical member (1). FIG. 2 shows a manufacturing procedure of the tappet (T), (A) shows a state before the cam receiving member (2) is press-fitted, and (B) shows a state during the press-fitting.

The inner diameter (D) of the upper end portion (1a) of the cylindrical member (1) before press-fitting is about the same as the vertical dimension of the annular piece (3) of the cam receiving member (2), and the annular piece The diameter is slightly smaller (for example, about 0.5 mm) than the outer diameter of (3). Cylindrical member
The inner diameter of the other parts excluding the upper end (1a) of (1) is an annular piece.
It has almost the same diameter as the outer diameter of (3).

On the outer peripheral edge of the lower end portion of the annular piece (3) of the cam receiving member (2), a sharp knife edge-shaped shearing blade portion (3
a) has been formed.

In order to connect the cylindrical member (1) and the cam receiving member (2) having such shapes in advance to each other, first, as shown in FIG.
As shown in, the cam receiving member (2) is placed on the upper surface of the cylindrical member (1) with their axes aligned.

Next, as shown in FIG. 2 (B), the cam receiving member (2) is pressed downward by a press or the like. Then, the inner peripheral wall of the upper end (1a) slightly reduced in diameter becomes the annular piece (3).
The cutting chips (6) that are thinly sheared by the blade portion (3a) and scraped off by the shearing sequentially fall downward.

In the step (B), the cam receiving member (2)
Is pressed until it abuts the upper end of the cylindrical member (1),
A tappet (T) as shown in is obtained.

Tappet (T) produced in this way
Since the inactive surface such as an oxide film formed on the inner peripheral surface of the aluminum alloy cylindrical member (1) is removed when the cam receiving member (2) is press-fitted, the cylindrical member (1) and the cam Receiving member
(2) means that the metal surfaces are in close contact with each other and both members (1) and (2)
Are extremely strongly bonded by the intermetallic bond. Figure 3-
FIG. 6 shows second to fifth embodiments of the tappet of the present invention.

The tappet of the second embodiment shown in FIG. 3 has an outer diameter slightly larger than the inner diameter of the upper end press-fitting portion of the cylindrical member (1) on the outer peripheral surface of the annular piece (3) of the cam receiving member (2). The two large and small press-fitting parts (7) (8) are replaced by the press-fitting parts (8) in the lower half.
While gradually forming the outer diameter of the
An annular groove (9) is formed on the outer peripheral surface of the middle portion where both press-fitting portions (7) and (8) intersect to store chips and the like during shearing.

The outer diameter difference between the press-fitting portions (7) and (8) is 0.2 mm.
It is good to set the degree. At the lower end of each press-fitting portion (7) (8), a knife edge-shaped blade portion (3a) is formed as in the first embodiment.

In the tappet of the third embodiment shown in FIG. 4, three large, medium and small press-fitting portions (10), (11) and (12) having different diameters are provided on the outer peripheral surface of the annular piece (3) in the lower order as in the above. In addition to forming it gradually so that the outer diameter of the press-fitting part is smaller than that of the upper part,
An annular groove (9) for accumulating chips and the like is formed on the outer peripheral surface of the portion where the press-fitting portions (10), (11) and (12) intersect. (3a) is a blade.

The dimensional difference between the press-fitting portions (10), (11) and (12) is preferably about 0.2 mm, as described above.

In the second and third embodiments,
Since the press-fitting portions having different diameters gradually shear the inner peripheral wall of the cylindrical member (1) step by step, there is an advantage that the shearing margin can be increased as compared with the tappet of the first embodiment described above, and accordingly, that much. The bond strength is increased.

In the tappet of the fourth embodiment shown in FIG. 5, the diameter of the upper end of the cylindrical member (1) is reduced, and an annular piece (2) of the cam receiving member (2) is formed on the outer peripheral surface of the reduced diameter portion (13). 3) was press-fitted while shearing. (3a) is a blade portion, and (9) is an annular groove for accumulating chips and the like. Also in this embodiment, the press-fitting portions having different diameters similar to those in FIGS. 3 and 4 are provided on the inner peripheral surface of the annular piece (3) stepwise so that the lower inner diameter is larger than the upper inner diameter. You may form in.

The tappet of the fifth embodiment shown in FIG. 6 has two annular branch pieces (15) (15) with a vertical groove (14) sandwiched at the upper end of a slightly thick cylindrical member (1). ) Are connected to each other, and the annular groove (16) is sandwiched between the cam receiving member (2) and the two annular pieces (17).
(17) and the outer annular piece (16) is a vertical groove of the cylindrical member (1).
(14) and the inner branch piece (15) to the vertical groove of the cam receiving member (2).
They are pressed into (16) respectively.

A blade portion (3a) is formed at the lower end of both annular pieces (17) in contact with the branch piece (15). (18) is a gap for storing chips and the like during shearing.

As described above, in the tappet of each of the above embodiments, the cylindrical member (1) and the cam receiving member (2) are
Since the oxide film and the like formed on the cylindrical member (1) are press-fitted while being removed, all have high bond strength.

Further, unlike the conventional tappet, since it is not necessary to form the annular receiving portion and the upper wall, not only the total length and outer diameter of the tappet but also the size of the guide hole of the cylinder head into which the tappet is fitted are small. In addition to being able to do so, further weight reduction can be achieved.

Of course, the present invention can be applied to the cylindrical member (1) made of a magnesium alloy or other light alloy.

A recess may be formed in the upper surface of the cam receiving member (2) for mounting a shim for adjusting the valve clearance.

[0035]

According to the present invention, the following effects can be obtained.

(A) Since the cam receiving member is only press-fitted into one opening end of the cylindrical member, the overall length and outer diameter can be made smaller than the conventional tappet, and the weight can be reduced.

(B) The coupling strength between the cam receiving member and the annular piece of the cam receiving member can be remarkably increased by a simple means of pressing the surface of the press-fitting portion while shearing the surface.

(C) Forming a blade on the annular piece facilitates shearing.

(D) If the outer diameter of the annular piece is made to differ stepwise and an annular groove is formed at the portion where the different outer diameters intersect each other, a large shearing margin can be taken and the bonding strength is increased accordingly. In addition, the cutting chips and the like at the time of shearing can be collected in the annular groove without leaving on the sheared surface.

[Brief description of drawings]

FIG. 1 is a central longitudinal front view showing a first embodiment of a tappet of the present invention.

2A and 2B are vertical cross-sectional views showing a manufacturing procedure of the tappet shown in FIG. 1, in which FIG. 2A is a state before a cam receiving member is press-fitted, and FIG.

FIG. 3 is a half sectional view of a main part showing a second embodiment of the tappet of the present invention.

FIG. 4 is a half cross-sectional view of an essential part showing the third embodiment.

FIG. 5 is a half cross-sectional view of an essential part showing the fourth embodiment.

FIG. 6 is a half cross-sectional view of an essential part of the fifth embodiment.

FIG. 7 is a central vertical sectional front view of a conventional tappet.

[Explanation of symbols]

 (1) Cylindrical member (1a) Upper end part (2) Cam receiving member (3) Annular piece (3a) Blade part (4) Pressing part (5) Escape groove (6) Chip (7) (8) (10) (11) (12) Press-fitting part (9) Annular groove (13) Reduced diameter part (14) Vertical groove (15) Branch piece (16) Vertical groove (17) Annular piece (18) Gap (T) Tappet

Claims (4)

[Claims] 1. A tappet for an internal combustion engine, comprising a disc-shaped cam receiving member made of a wear-resistant metallic material and press-fitted into one opening end of a cylindrical member made of a light metallic material. 2. A wear-resistant metal, which is formed into a disc shape at one open end of a cylindrical member made of a light metal material, and on one side of which a ring-shaped piece having a required length facing the plate thickness direction is continuously provided. A method for manufacturing a tappet for an internal combustion engine, comprising press-fitting the annular piece of a material cam receiving member while shearing one of the inner and outer peripheral surfaces of the opening end. 3. The method for producing a tappet for an internal combustion engine according to claim 2, wherein a shearing blade portion is formed on the peripheral edge of the annular piece on the side in contact with the cylindrical member. 4. An annular piece press-fitted to the inner peripheral surface side of a cylindrical member, wherein the outer diameter of the annular piece is made different so that the press-fitting direction side gradually becomes smaller, and different outer diameters intersect. The method for manufacturing a tappet for an internal combustion engine according to claim 2 or 3, wherein an annular groove is formed in the portion.