JPH10153103A - Connecting method of cam receiving plate in tappet for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate connecting work, and provide stable connecting strength by forming a flame spraying layer on outer peripheral surfaces of a tappet main body and a cam receiving plate after matching both outer peripheral surfaces of a tappet main body whose upper surface is closed and the cam receiving plate having the same diameter of the tappet main body and abrasion resistance performance with each other, and mounting both outer peripheral surfaces on an upper surface of the tappet main body. SOLUTION: Blast treatment and the like are carried out on an outer peripheral surface of an aluminum alloy made tappet main body 1 whose upper surface is closed, and its surface is formed as a rough surface. Outer peripheral surfaces of the tappet main body 1 and a cam receiving plate 2 made of abrasion resistance performance metal material having the same diameter as the tappet main body 1 are matched with each other, and both outer peripheral surfaces are mounted on an upper surface of the tappet main body 1, and then iron flame spraying material 6 is ejected in a spray shape while vertically moving in reciprocation a flame spray gun 5 faced to a side of the tappet main body 1. The flame spray layer 3 is thus formed on the outer peripheral surfaces of the tappet main body 1 and the cam receiving plate 2, and also the cam receiving plate 2 is integratedly connected to the tappet main body 1 on the flame spray layer 3. The thickness of the flame spray layer 3 is not especially limited, but it is set to 0.1 to 0.3mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for easily connecting a cam receiving plate to a surface of a tappet used in an internal combustion engine, which is in sliding contact with a cam.

[0002]

2. Description of the Related Art Tappets used in a direct-acting type valve train of an internal combustion engine include, in order to reduce the weight of the valve train,
Some are formed of an aluminum alloy. Since this is inferior in strength and abrasion resistance as compared with a normal steel tappet, as shown in FIG.
A cam receiving plate (2) made of an abrasion-resistant metal material is fixed to the upper surface on which the cam slides by brazing or the like, or a sprayed layer of a ferrous metal (3) is formed on the outer peripheral surface of the tappet body (1). And so on.

[0003]

As described above, joining the cam receiving plate (2) by brazing is troublesome and requires joining materials having different melting points. It is difficult to control both temperatures, and there is a possibility that the bonding strength varies.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an internal combustion engine has been developed which utilizes a sprayed layer formed on a tappet body to facilitate a joining operation and obtain a stable joining strength. It is an object of the present invention to provide a method for connecting a cam receiving plate in an engine tappet.

[0005]

According to the present invention, the above-mentioned problem is solved as follows. (1) On a top surface of a cylindrical tappet body having a closed upper surface, a wear-resistant cam receiving plate having the same diameter as the tappet body is provided.
After placing those outer peripheral surfaces in alignment with each other,
By forming a continuous sprayed layer on the outer peripheral surface of the tappet body and the cam receiving plate, the tappet body and the cam receiving plate are joined.

(2) In the above item (1), a concave portion is formed on one of the contact surfaces of the tappet body and the cam receiving plate, and a convex portion is formed on the other, and the concave and convex portions are fitted to each other.

(3) In the above item (1) or (2), an inward annular groove is formed on an outer peripheral surface of a contact portion between the tappet body and the cam receiving plate.

(4) In the above item (1) or (2), a reduced diameter portion is formed on the upper outer peripheral edge of the cam receiving plate.

[0009]

1 and 2 show a first embodiment of the present invention in the order of steps. First, as shown in FIG. 1, the outer peripheral surface of an aluminum alloy tappet body (1) formed into a cylindrical shape whose upper surface is closed by cold forging is subjected to a blast treatment or the like to obtain a rough surface (4). . This is a surface treatment for improving the adhesion of the sprayed material and improving the peel strength when forming the sprayed layer in the next step.

[0010] Next, as shown in FIG.
A cam receiving plate (2) made of a wear-resistant metal material (for example, a steel plate) having an outer diameter equal to that of the tappet body (1) is positioned on the upper surface of (1) so that their outer peripheral surfaces are aligned with each other. Spray gun (5) facing the side of the tappet body (1)
The iron-based thermal spray material (6) is sprayed in the form of a spray while reciprocating vertically.

Then, the tappet body (1) and the cam receiving plate
A continuous sprayed layer (3) is formed on the outer peripheral surface of (2), and the cam receiving plate (2) is formed by the sprayed layer (3).
It is integrally connected to (1). The thickness of the thermal spray layer (3) is preferably 0.1 to 0.3 mm.

FIG. 3 shows a tappet obtained according to a second embodiment of the present invention. In this embodiment, the downwardly projecting annular convex portion (2a) formed at the center of the lower surface of the cam receiving plate (2) is press-fitted into the concave hole (1a) formed at the center of the upper surface of the tappet body (1), and then subjected to thermal spraying. The layer (3) has been formed.

In this manner, not only is it easy to position the cam receiving plate (2) when mounting it on the upper surface of the tappet body (1), but also, the cam receiving plate (2) has a larger sliding load than the cam. Does not apply a load directly to the thermal sprayed layer (3) at the joint, sufficient bonding strength can be obtained even when the thermal sprayed layer (3) is thinned. In this embodiment, a concave hole may be formed on the cam receiving plate (2) side and a convex portion may be formed on the tappet body (1) side.

FIG. 4 is an enlarged view of a main part of a tappet obtained according to a third embodiment of the present invention. In this embodiment, an inward V-shaped annular groove (7) is formed on the outer peripheral surface of the contact portion between the tappet body (1) and the cam receiving plate (2), and then a sprayed layer (3) is formed. It is.

By doing so, the thermal spray material enters the annular groove (7), and the joining area between the tappet body (1) and the cam receiving plate (2) increases, so that the bonding strength of the cam receiving plate (2) is increased. Grows more. The shape of the annular groove (7) in this embodiment is
The shape is not limited to a V-shape, but may be concave inward.

FIG. 5 is an enlarged view of a main part of a tappet obtained according to a fourth embodiment of the present invention. In this embodiment, a stepped portion (8) is provided on the upper outer peripheral edge of the cam receiving plate (2). ) Is formed to reduce the diameter of a part thereof, and the sprayed layer (3) is formed on the entire outer peripheral surface including the step (8).

In this case, the thermal sprayed layer (3) is continuously formed up to the upper outer peripheral edge of the cam receiving plate (2), so that the bonding strength of the cam receiving plate (2) is increased as described above.

FIG. 6 is an enlarged view showing a main part of a tappet obtained according to a fifth embodiment of the present invention. In this embodiment, the outer peripheral surface of the cam receiving plate (2) is gradually reduced in diameter at the upper side. The diameter of a part of the tapered surface (9) is reduced, and a sprayed layer (3) is formed on the entire outer peripheral surface. Also in the fifth embodiment, as in the fourth embodiment, the coupling strength of the cam receiving plate (2) increases.

According to the present invention, in addition to the tappet body (1) made of an aluminum alloy as in the above embodiment, the tappet body (1) is formed of an inexpensive iron-based material (for example, low carbon steel). It can also be applied when a wear-resistant cam receiving plate (2) is connected to the cam. In this case, since the adhesion of the sprayed material is good,
The surface treatment for forming the rough surface (4) may be omitted.

[0020]

According to the present invention, the following effects can be obtained. (a) At the same time as forming the sprayed layer on the outer peripheral surface of the tappet main body, the cam receiving plate can be joined, so that the joining work is extremely easy and stable joining strength is achieved as compared with conventional brazing or the like. can get.

(B) According to the second aspect of the present invention, since the side slip load acting on the cam receiving plate is prevented from being directly applied to the thermal sprayed layer at the joint, the cam sliding plate is peeled off. There is no danger that the bonding strength of this will decrease.

(C) According to the third aspect, the joint area between the tappet body and the cam receiving plate is increased, so that the coupling strength of the cam receiving plate is further increased.

(D) According to the fourth aspect, the thermal sprayed layer is formed continuously up to the outer peripheral edge of the upper portion of the cam receiving plate, so that the bonding strength of the cam receiving plate is increased as described above.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing a surface treatment step for a tappet body according to a first embodiment of the present invention.

FIG. 2 is a vertical front view of the center showing a spraying process after a cam receiving plate is placed.

FIG. 3 is a front view in the center longitudinal section of a tappet obtained according to a second embodiment of the present invention.

FIG. 4 is an enlarged vertical sectional view of a main part of a tappet obtained according to a third embodiment.

FIG. 5 is an enlarged vertical sectional view of a main part of a tappet obtained according to a fourth embodiment.

FIG. 6 is an enlarged vertical sectional view of a main part of a tappet obtained according to a fifth embodiment.

FIG. 7 is a front view in the center longitudinal section of a tappet obtained by a conventional method.

[Explanation of symbols]

 (1) Tappet body (1a) Concave hole (recess) (2) Cam receiving plate (2a) Convex portion (3) Thermal spray layer (4) Rough surface (5) Thermal spray gun (6) Thermal spray material (7) Annular groove ( 8) Step (9) Tapered surface

Claims (4)

[Claims] An abrasion-resistant cam receiving plate having a diameter equal to that of a cylindrical tappet body having a closed upper surface is placed on the upper surface of the tappet body with their outer peripheral surfaces aligned with each other. A method for connecting a cam receiving plate in a tappet for an internal combustion engine, wherein the tappet body and the cam receiving plate are connected by forming a continuous sprayed layer on the outer peripheral surface of the tappet main body and the cam receiving plate. 2. The internal combustion engine according to claim 1, wherein a concave portion is formed on one of the contact surfaces of the tappet body and the cam receiving plate, and a convex portion is formed on the other, and the concave and convex portions are fitted to each other. Method of connecting the cam receiving plate in the tappet. 3. The method according to claim 1, wherein an inward annular groove is formed on an outer peripheral surface of a contact portion between the tappet body and the cam receiving plate. 4. The method of connecting a cam receiving plate in an internal combustion engine tappet according to claim 1, wherein a reduced diameter portion is formed on an upper outer peripheral edge of the cam receiving plate.