JP2002030907A - Tappet for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce cost by improving abrasion resistance of an outer peripheral surface of a tappet main body without thermal spraying, plating, etc. SOLUTION: A tappet main body 7 is formed of light alloy and a thin cylindrical metallic covered cylinder 8 is fitted on its outer peripheral surface on a tappet 6 for an internal combustion engine constituted by providing a recessed hole 9 on an upper surface of a top wall 7a on the tappet main body 7 forming a topped cylindrical shape and fitting a disc type shim 10 in this recessed hole 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lightweight and inexpensive tappet for an internal combustion engine.

[0002]

2. Description of the Related Art In recent years, tappets used in a direct-acting type valve train in an internal combustion engine have been replaced with steel in order to reduce the inertial mass of the valve train and improve engine performance. It tends to be formed by an aluminum alloy.

[0003] Tappets made of aluminum alloy are inferior in mechanical strength and abrasion resistance as compared with those made of steel.
Therefore, conventionally, as shown in FIG. 7, a cylinder head (2) in a tappet body (1) made of an aluminum alloy is conventionally used.
The outer peripheral surface (1a) that is fitted and slid into the guide hole (2a) is formed with, for example, an iron-based thermal spray coating or subjected to a surface treatment by Ni-based plating. The sliding top wall (1
A relatively thick hard metal shim (5) made of chromium molybdenum steel or the like is fitted into the recess (4) on the upper surface of (b) to improve the wear resistance of those parts. .

[0004]

In order to form a thermal spray coating on the outer peripheral surface, as in the above-mentioned conventional tappet, the outer peripheral surface is roughened by blasting or the like, and finish processing after thermal spraying is performed. Since these are indispensable, it is necessary to set up a dedicated machine for them in addition to the thermal spraying apparatus, which increases equipment costs and man-hours and increases manufacturing costs.

On the other hand, even in the surface treatment by Ni-based plating, a complicated pretreatment step and a long plating step are required, so that an increase in manufacturing cost is inevitable.

Further, since a relative rotation occurs between the tappet body (1) and the shim (5), a soft tappet body is provided.
The bottom surface and the inner peripheral surface of the concave portion (4) on the (1) side may be worn, and the shim (5) may rattle in the concave portion (4).

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and improves the abrasion resistance of the outer peripheral surface of a tappet body without spraying, plating, or the like, reduces manufacturing costs, and reduces the cost for shim fitting. It is an object of the present invention to provide a lightweight tappet for an internal combustion engine that can suppress wear of a concave portion.

[0008]

According to the present invention, the above-mentioned problem is solved as follows. (1) In a tappet for an internal combustion engine in which a concave hole is formed in the upper surface of a top wall of a tappet body having a cylindrical shape with a top and a disk-shaped shim is fitted in the concave hole, the tappet body is lightened. A thin-walled cylindrical metal covering tube is fitted on the outer peripheral surface of an alloy.

(2) In the above item (1), the upper and lower ends of the coating tube are bent inward to engage with the upper and lower end surfaces of the tappet body.

(3) In the above item (1) or (2), an inwardly bent locking piece having an inverted L-shaped cross section is provided at the upper end of the coating cylinder, and the downward piece is attached to the top wall. Is fitted into the recessed portion by closely contacting the inner peripheral surface thereof so that the shim is inserted.

(4) A tappet for an internal combustion engine in which a concave hole is formed in the upper surface of a top wall of a tappet body having a cylindrical shape with a top and a disk-shaped shim is fitted in the concave hole. The main body is formed of a non-ferrous material having a low specific gravity, and an outer cylinder made of a thin metal formed by connecting an upper surface plate complementary to the upper surface of the tappet main body to the upper end of the cylindrical portion on the entire outer peripheral surface thereof, from above. The upper surface of the upper plate is fitted with a concave hole, and the shim is fitted into the concave hole.

(5) In any one of the above items (1) to (4), a solidifiable filler having an adhesive property is sealed in a gap between the tappet body and the coating tube or the outer tube.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention. A tappet (6) has a cylindrical tappet body (7) whose upper surface is closed by a top wall (7a), and is fitted on the outer peripheral surface thereof. Wearing thin cylindrical shape (exaggerated in the figure)
, A disk-shaped shim (10) removably fitted in a concave hole (9) in the upper surface of the top wall (7a), and a center of the lower surface of the top wall (7a). And a small-diameter disc-shaped tip (11) fitted to the thick portion of the body, and between the tappet body (7) and the coating cylinder (8), as shown in FIG. An adhesive filler (for example, epoxy resin) (12) that fills a gap formed therebetween is enclosed.

The tappet body 7 is made of, for example, Al-C
It is formed of a light alloy such as an aluminum alloy such as u-Mg, Al-Cu, or Al-Cu-Si, or a magnesium alloy such as Mg-Al-Zn.

The coating tube (8) is made of a cold-rolled steel plate (SPCC, SPCD, SPCE) having a thickness of about 0.1 to 0.2 mm, and is deep drawn to form an inward annular ring at the upper end. Folding locking piece
It is formed in a cylindrical shape having (8a).

The shim (10) and the chip (11) are formed by punching a steel plate made of, for example, chromium molybdenum having a thickness of 1 to 3 mm, and are subjected to a hardening treatment such as carburizing if necessary.

The covering cylinder (8) has a bent locking piece (8a) at its upper end.
Is in contact with the upper end of the tappet body (7).
The lower end of (8) is bent inward to be fixed to the tappet body (7).

The installation of the coating cylinder (8) on the tappet body (7) is performed in the following procedure.

First, a coating tube (8) is formed in advance as shown in FIG. That is, the above-described cold-rolled steel sheet is formed into a bottomed cylindrical shape by deep drawing, and then the bottom wall is formed by a punch (13) having a diameter slightly smaller than the inner diameter.
(8b) is punched into a circle. The peripheral end of the bottom wall (8b) that has been punched out is used as a bent engagement piece (8a).

As shown in FIG. 4, the covering cylinder (8) formed as described above is placed on a tappet body (7) held by a support jig (not shown) from above to bend the locking piece. (8a) is fitted upward. The tip (11) is previously fitted to the tappet body (7).

At this time, the filler (12) such as a semi-cured epoxy resin is applied to the outer peripheral surface of the tappet body (7) or the inner peripheral surface of the coating cylinder (8) in advance, so that the fitting is performed. At the time of joining, the gap between the tappet body (7) and the coating cylinder (8) is filled with a filler (12) (the filler is not shown because it is extremely thin).

After the covering tube (8) is fitted until the bent locking piece (8a) abuts on the upper end of the tappet body (7), the covering tube (8) projects from the tappet body (7). If the end is plastically deformed inward as indicated by the two-dot chain line and is engaged with the lower end of the tappet body (7), the coating cylinder (8) is firmly fixed.

It should be noted that, if the bent locking pieces (8a) are formed in advance as described above, the labor for bending the upper end of the coating tube (8) inward after fitting is saved, which is convenient. But the sheath tube (8)
May be formed into a straight cylindrical shape, and after fitting this into the tappet body (7), the upper end thereof may be bent inward.

In this state, the filler (12) is left to solidify, and the shim (10) is fitted into the recess (9) to obtain a tappet (6) as shown in FIG.

In the tappet (6) of the above embodiment,
Since the abrasion resistance of the outer peripheral surface can be improved by a very simple means of mechanically fixing the coating cylinder (8), the production cost is greatly reduced as compared with conventional thermal spraying, plating and the like.

Further, since the gap between the tappet body (7) and the coating cylinder (8) is filled with the filler (12), the outer peripheral surface of the tappet body (7) is smoothed by finishing or the like. And the processing cost can be reduced.

In addition, since the filler (12) acts as a binder and has a function of absorbing vibration,
(8) is firmly fixed to the tappet body (7), and the vibration noise emitted from the tappet (6) is also reduced.

Further, the coating cylinder (8) has a thickness of 0.1 to 0.1.
Since the tappet (6) is extremely thin, about 2 mm, the weight increase of the tappet (6) due to the attachment is small, almost equal to the conventional thermal spraying, and does not go against the weight reduction of the tappet.

FIG. 5 shows a second embodiment of the present invention in which main parts are enlarged. In this embodiment, a bent locking piece (14) having an inverted L-shaped cross section is formed at the upper end of the coating tube (8), and the downwardly directed piece (14a) that forms an annular shape is fitted to the concave portion of the tappet body (7). It is fitted into the hole (9) from above so as to be in close contact with the inner peripheral surface.

The lower end of the coating tube (8) is bent inward and engaged with the lower end of the tappet body (7) as in the above embodiment. The same filler (12) as described above is sealed between the tappet body (7) and the covering cylinder (8).

The shim (10) is provided with a downwardly extending piece (14) of the bent locking piece (14).
It is detachably fitted in a concave hole (15) surrounded by a). Accordingly, in the second embodiment, in addition to the same operation and effect as the first embodiment, the inner peripheral surface of the concave hole (9) of the tappet body (7) with which the outer peripheral surface of the shim (10) comes into contact. Can be prevented from being worn.

FIG. 6 shows a third embodiment of the present invention by enlarging a main part thereof.
An extremely thin (0.1 to 0.1) having a cylindrical portion (16a) and an upper surface plate (16b) at the upper end thereof, which almost complements the shape of the top surface of the tappet body (7).
0.2 mm) of the outer cylinder (16) so that the downwardly protruding portion (16c) of the center of the upper surface plate (16b) is tightly inserted into the recess (9) of the tappet body (7). Fitted from above.

The shim (10) is removably fitted in a recess (17) formed in the center of the upper surface of the upper plate (16b).

The filler (12) is supplied to the tappet body (7) and the outer cylinder (1).
6) enclosed between all contact surfaces. The filling procedure of the filler (12) is as follows. Before fitting the outer cylinder (16), a semi-cured epoxy resin is placed on the upper surface of the concave hole (9) of the tappet body (7), and this is placed in the outer cylinder. At the time of fitting (16), if pressure is applied by the upper surface plate (16c), it automatically flows into the gap.

The outer cylinder (16) can be formed at once by deep drawing of a cold-rolled steel sheet.

In the third embodiment, the tappet body
The entire top surface of (7) is covered with the upper plate (16b) of the outer cylinder (16),
Since the shim (10) is fitted in the recess (16) formed in the tappet body (7), the shim (10) does not directly contact the tappet body (7). (10) It is possible to prevent wear of the entire fitting recess (9).

The top surface of the tappet body (7) and the outer cylinder (16)
Since the filler (12) is also enclosed between the top surface of the tappet and the outer surface of the tappet body (7), a concave hole for shim fitting is provided.
There is no need to apply finishing to (9), the tappet body (7)
Can be used in an unprocessed state while being subjected to forging and T6 heat treatment based on JIS, and the processing cost can be significantly reduced.

In the case of the tappet in which the entire outer peripheral surface of the tappet body (7) is covered by the outer cylinder (16) as in the third embodiment, the wear resistance is ensured by the outer cylinder (16). The tappet body (7) only needs to have only mechanical strength. Therefore, as the material, in addition to the above-mentioned aluminum alloy and magnesium alloy, polyamide, polyacetal, engineering plastics such as polycarbonate, fiber-reinforced plastic containing glass fiber or carbon fiber, alumina, zirconia, silicon nitride,
Fine ceramics such as silicon carbide, or low specific gravity non-ferrous materials such as titanium alloys can also be used.

The present invention is not limited to the above embodiment. In the above embodiments, the tappet body
Although the filler (12) is sealed between (7) and the coating cylinder (8) and the outer cylinder (16), when the surface of the tappet body (7) is made to be a smooth surface, the filler ( The encapsulation of 12) may be omitted. In some cases, the chip (11) is omitted.

[0040]

According to the first aspect of the present invention, the abrasion resistance of the outer peripheral surface of the tappet can be easily obtained by simply fitting a metal coating tube without using conventional thermal spraying or plating. The production cost is greatly reduced, since it can be improved by means. Further, since the coating cylinder is thin (for example, 0.1 to 0.2 mm), the weight increase is slight, and does not go against the weight reduction of the tappet.

According to the second aspect of the present invention, the coating cylinder is firmly fixed to the outer peripheral surface of the tappet body.

According to the third aspect of the present invention, since the outer peripheral surface of the shim does not directly contact the inner surface of the concave hole of the tappet main body, wear of the inner peripheral surface can be suppressed.

According to the fourth aspect of the present invention, in addition to the effect of the first aspect, since the entire shim is fitted into the concave hole of the upper surface plate of the outer cylinder, the shim is formed on the tappet main body. Wear of the entire recess is prevented, and there is no danger that the shim will rattle in the recess.

According to the fifth aspect of the present invention, the tappet body, the coating cylinder, and the outer cylinder are firmly fixed using the filler as a binder, and the filler absorbs vibrations. Noise can be reduced. Also,
Since it is not necessary to apply a finishing process to the surface of the tappet body to make it a smooth surface, the processing cost required for it is reduced, and a more inexpensive tappet can be provided.

[Brief description of the drawings]

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

2 is an enlarged vertical sectional view of a main part of FIG. 1;

FIG. 3 is a vertical cross-sectional view showing a molding procedure of a coating cylinder.

FIG. 4 is a longitudinal sectional view showing the procedure for fixing the coating cylinder to the tappet body.

FIG. 5 is an enlarged longitudinal sectional view of a main part showing a second embodiment of the present invention.

FIG. 6 is an enlarged vertical cross-sectional view of a main part, similarly showing a third embodiment.

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

[Explanation of symbols]

 (6) Tappet (7) Tappet body (7a) Top wall (8) Covering cylinder (8a) Bend locking piece (8b) Bottom wall (9) Concave hole (10) Shim (11) Tip (12) Filler (13) Punch (14) Bend locking piece (14a) Downward piece (15) Concave hole (16) Outer cylinder (16a) Tube section (16b) Top plate (16c) Downward bulging section

Continued on front page F term (reference) 3G016 AA06 AA19 BB04 BB05 BB06 CA04 CA15 CA17 CA19 CA32 CA34 CA35 CA52 EA08 EA12 FA06 FA29 FA34 FA35 FA37 GA02

Claims (5)

[Claims] 1. A tappet for an internal combustion engine, wherein a concave hole is provided in an upper surface of a top wall of a tappet body having a cylindrical shape with a top and a disk-shaped shim is fitted in the concave hole. Is formed from a light alloy, and a thin-walled cylindrical metal covering tube is fitted on the outer peripheral surface thereof. 2. The tappet for an internal combustion engine according to claim 1, wherein the upper and lower ends of the coating cylinder are bent inward to engage with the upper and lower end faces of the tappet body. 3. An inwardly bent locking piece having an inverted L-shaped cross section is provided at the upper end of the coating cylinder so that the shim is inserted into the recess in the top wall. 3. The tappet for an internal combustion engine according to claim 1 or 2, wherein the tappet is fitted in close contact with an inner peripheral surface of the tappet. 4. A tappet for an internal combustion engine, wherein a concave hole is provided in an upper surface of a top wall of a tappet body having a cylindrical shape with a top and a disk-shaped shim is fitted in the concave hole. Is formed of a non-ferrous material of low specific gravity, and, on the entire outer peripheral surface thereof, an outer cylinder made of a thin metal formed by continuously connecting an upper surface plate complementary to the upper surface of the tappet body to the upper end of the cylindrical portion,
A tappet for an internal combustion engine, wherein the tappet is fitted from above, and a recess is formed in the upper surface of the upper plate, and the shim is fitted in the recess. 5. The tappet for an internal combustion engine according to claim 1, wherein an adhesive solidifying filler is sealed in a gap between the tappet body and the coating cylinder or the outer cylinder.