JP2002021511A - Tappet for internal combustion engine and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce weight of a tappet and its manufacturing cost. SOLUTION: A metallic coated cylinder 8 having a thin wall cylindrical shape is fitted in an outer peripheral face of a tappet main body 7 made of a non-ferrous material having low specific gravity, having a top, and forming a cylindrical shape. A thin-walled cam receiving plate 9 made of hard metal is put on a top face of the tappet main body 7, an upper face in a peripheral end part of the cam receiving plate 9 is pressed by bending an upper end part of the coated cylinder 8 inward, and the coated cylinder 8 and the cam receiving plate 9 are integrally fixed on the tappet main body 7 by bending a projecting end part from a lower end of the tappet main body 7 of the coated cylinder 8 inward.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[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 aluminum in order to reduce the inertial mass of the valve train and improve engine performance. It tends to be formed by alloys.

[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. 9, a cylinder head in a tappet body (1) made of an aluminum alloy is conventionally used.
The outer peripheral surface (1a) which is fitted into the guide hole (2a) of (2) and slides,
For example, a chromium-molybdenum steel or the like is formed in a concave portion (4) on the upper surface of the top wall (1b) on which a cam (3) slides by forming an iron-based thermal spray coating or performing a surface treatment by Ni-based plating. A relatively thick hard metal shim (5)
The wear resistance of those parts is increased.

[0004]

In order to form a sprayed coating on the outer peripheral surface, as in the above-described conventional tappet, the outer peripheral surface is roughened by blasting or the like, or a finishing process after thermal spraying is performed. Is indispensable, so outside of the spraying equipment,
These dedicated machines need to be installed, 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.

When a relatively thick shim (5) is mounted on the top wall (1b) with which the cam (3) slides, the weight ratio of the shim (5) in the entire tappet is large, and the purpose is to reduce the weight. There is also a problem that the effect of using the aluminum alloy for the tappet body (1) is reduced by half.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is possible to form a tappet body from a lightweight material and improve the wear resistance of its outer peripheral surface without spraying or plating. It is an object of the present invention to provide a tappet for an internal combustion engine and a method for manufacturing the same, which can achieve a great reduction in cost and weight by using a thin receiving plate in place of.

[0008]

According to the present invention, the above-mentioned problem is solved as follows. (1) A thin-walled cylindrical metal covering tube is fitted on the outer peripheral surface of a tappet body having a cylindrical shape with a low specific gravity and made of non-ferrous material, and a hard metal thin-walled tube is fitted on the top surface of the tappet body. Place the cam receiving plate, and put the upper surface of the peripheral end of this cam receiving plate
By pressing the upper end of the coating cylinder inward by bending it inward, and bending the projecting end of the coating cylinder from the lower end of the tappet body inward, the coating cylinder and the cam receiving plate are tappeted. It is fixed integrally to the main body.

(2) In the above item (1), a circular projection is formed at the center of the top surface of the tappet body, and the cam receiving plate is fitted to the projection.

(3) In the above item (1) or (2), a downward engaging step portion at which the inwardly bent portion at the upper end of the coating cylinder can be properly fitted on the upper surface of the peripheral end portion of the cam receiving plate. Is provided, the cam receiving plate and the upper surface of the coating cylinder are made continuous on the same surface.

(4) A thin metal outer cylinder having an upper surface plate connected to the upper end of a cylindrical portion is fitted over the entire outer peripheral surface of the tappet body having a cylindrical shape with a low specific gravity and made of a non-ferrous material from above. Then, the outer cylinder is integrally fixed to the tappet body by bending inwardly a protruding end of the outer cylinder from the lower end of the tappet body.

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

(6) In any one of the above items (1) to (5), the low specific gravity non-ferrous material is selected from aluminum alloy, magnesium alloy, plastic, ceramics, and titanium alloy.

(7) The method for producing a tappet according to any one of the above items (1) to (3) or (5) or (6), wherein the tappet body has a cylindrical top with a low specific gravity and is made of a non-ferrous material. A thin-walled cylindrical metal covering tube having an inwardly bent engagement piece at the upper end, which can be fitted on the outer peripheral surface thereof; and a thin hard metal cam receiver mountable on the top surface of the tappet body. The cover tube is separately formed in advance, and in a state where the cam receiving plate is placed on the top surface of the tappet main body, the covering cylinder is fitted to the tappet main body with one side of the bent engagement side facing upward. And, in a state where the upper surface of the peripheral end portion of the cam receiving plate is pressed by the bending locking piece, the projecting end portion of the covering cylinder from the lower end of the tappet body is bent inward,
Engage with the lower end of the tappet body.

(8) In the above item (7), a solidifying filler having an adhesive property is placed on the top surface of the tappet body, and the filler is pressed when the cam receiving plate is pressed, whereby the tappet body and the tappet body are pressed. It is sealed in the gap between the coating cylinder and the cam receiving plate.

(9) In the above item (7) or (8), an engaging step portion is provided on the upper surface of the peripheral end of the cam receiving plate so that the bent locking piece of the coating cylinder can be properly fitted from above. .

(10) In any one of the above items (7) to (9), the cold-rolled steel sheet is deep-drawn and formed into a cylindrical shape with a bottom, and the bottom wall is slightly pressed with a small-diameter punch. The coating cylinder is formed by punching in a circular shape, and the peripheral end of the bottom wall of the coating cylinder left at the time of the punching is used as an inward bent locking piece.

[0018]

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. Ultra-thin cylindrical shape (exaggerated in the figure)
And a thin disk-shaped cam receiving plate (9) fixed to the upper surface of the top wall (7a), and also fitted to a thick portion at the center of the lower surface of the top wall (7a). 2 and 3, between the tappet body 7 and the covering cylinder 8 and the cam receiving plate 9 as shown in FIG. 2 and FIG. An adhesive filler (for example, epoxy resin) (11) that fills a gap formed between them is enclosed.

The tappet body (7) is made of Al-Cu-M
g-based, Al-Cu-based, Al-Cu-Si-based aluminum alloys, Mg-Al-Zn-based magnesium alloys,
Hard engineering plastics such as polyamide, polyacetal and polycarbonate, fiber reinforced plastics containing glass fiber and carbon fiber, and alumina
(Al ₂ O ₃ ), zirconia (ZrO ₂ ), silicon nitride (Si
₃ N _4), fine ceramics such as silicon carbide (SiC),
Alternatively, it is formed of a non-ferrous material having a low specific gravity such as a titanium alloy.

The coating cylinder (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 cam receiving plate (9) is formed of a hard and wear-resistant material such as carburized chromium molybdenum steel, bearing steel, tool steel or the like to a thickness of about 0.2 to 0.4 mm. ing.

As shown in the enlarged view of FIG. 2, the upper surface of the peripheral end of the cam receiving plate (9) has vertical dimensions substantially equal to the thickness of the bent locking piece (8a) of the coating cylinder (8). In addition, a downward engaging step (12) is formed so that the bent locking piece (8a) can be properly fitted from above.

The cam receiving plate (9) has an engaging step (1) on its outer peripheral portion.
In a state where 2) is pressed by the bent locking piece (8a), as shown in FIG. 3, the lower end of the coating tube (8) is moved along the chamfered portion (7b) at the lower end of the tappet body (7). The tappet body is bent inward, and the lower end is plastically deformed inward so as to form a U-shaped cross section.
By being engaged with the lower end of (7), it is fixed to the upper surface of the top wall (7a).

At the same time as the fixing of the cam receiving plate (9),
(8) is prevented from falling off and is integrally fixed to the outer peripheral surface of the tappet body (7).

It is to be noted that the bent locking piece in the coating cylinder (8)
(8a) and the connecting part upper surface of the engaging step part (12) of the cam receiving plate (9)
It is preferable that the tappet 6 be continuous on the same surface without any gap. In this case, the entire upper surface of the tappet 6 can be used as a sliding contact surface of a cam (not shown) to increase the travel area.

Next, the manufacturing procedure of the tappet (6) will be described. First, a tappet body (7), a covering cylinder (8), a cam receiving plate (9), and a tip (1
0) is previously formed from the above-described material as follows.

When the tappet body (7) is made of aluminum alloy or magnesium alloy, it is cold or warm forged, when it is made of plastic, it is formed by molding, and when it is made of fine ceramics, it is Each of them can be formed by firing the raw material powder.

As shown in FIG. 4, the coating cylinder (8) is formed into a bottomed cylindrical shape by deep drawing, and then the bottom wall (8b) is made circular by a punch (13) having a diameter slightly smaller than the inner diameter. The peripheral end of the bottom wall (8b) formed by punching and remaining can be a bent engagement piece (8a).

The cam receiving plate (9) is formed by punching a steel plate into a disk shape, and the engaging step (12) on the upper surface of the peripheral end is formed by applying a high pressure by a press or the like to cause plastic deformation. sell.

The chip (10) is formed by stamping or sintering a steel plate.

FIGS. 5 and 6 show a specific manufacturing procedure when the tappet body (7) is made of an aluminum alloy. First, the tappet body (7), the covering cylinder (8), the cam receiving plate (9), and the tip (10) are previously formed in the above-described manner, and the tip bottom is provided on the inner bottom surface of the tappet body (7). (10) is fitted.

It should be noted that the tappet body (7) is in a state of being subjected to T6 heat treatment (solution treatment) according to JIS after forging or forging, and the outer peripheral surface thereof is not subjected to finish processing, but is left as an uneven surface. is there. This is to omit the finish machining step and reduce the cost.

As shown in FIG. 5, the tappet body (7) is
After being held by a support jig (not shown) inserted into the cylindrical portion, a required amount of a semi-cured epoxy resin or the like (11) is placed on the upper surface of the top wall (7a).

Next, the cam receiving plate (9) is placed on the top surface of the tappet body (7) without strongly pressing the filler (11).

Next, the covering cylinder (8) whose inner diameter is slightly larger than the maximum outer diameter of the tappet body (7) is bent by the bent engagement piece.
The tappet body (7) was fitted into the tappet body (7) with the (8a) side facing upward, and the bent locking piece (8a) was fitted to the engaging step (12) at the peripheral end of the cam receiving plate (9). In this state, the coating tube (8) is strongly pressed. This allows
The filler (11) placed on the top surface of the tappet body (7) is pressurized, and the surface of the tappet body (7) is covered with the coating cylinder (8) and the cam receiving plate.
While filling the gap formed between the tappet and the tappet body (9), the excess filler (11) flows out from the lower end of the tappet body (7).

Next, as shown by the two-dot chain line in FIG. 6 (the filler is not shown because it is extremely thin), the protruding end of the coating cylinder (8) from the tappet body (7) is directed inward as shown by the arrow. And is engaged with the lower end of the tappet body (7).

In this state, if the filler (11) is allowed to stand until it solidifies, the tappet body can be resembled as shown in FIGS.
A tappet (6) in which the covering cylinder (8) and the cam receiving plate (9) are integrally fixed to (7) and the filler (11) is sealed in the gap between them is obtained.

In the tappet (6) thus obtained, the tappet body (7) is made of an aluminum alloy, and the coating cylinder (8) and the cam receiving plate (9) are extremely thin. Significant measurement compared to steel tappet.

Further, the wear resistance of the outer peripheral surface and top surface of the tappet (6) can be improved by a simple means of mechanically fixing the coating cylinder (8) and the cam receiving plate (9). The manufacturing cost is greatly reduced as compared with thermal spraying or plating.

Further, the gap formed between the covering cylinder (8) and the cam receiving plate (9) is adhered to the outer peripheral surface of the tappet body (7) without intentional machining (finishing). Since the filler is filled with the filler (11), the cost required for finishing the surface of the tappet body (7) is reduced. Moreover, since the filler (11) acts as a binder and also has a vibration absorbing action, the covering cylinder (8) and the cam receiving plate (9) are firmly fixed to the tappet body (7), and the tappet ( 6) Vibration noise can also be reduced.

FIG. 7 shows a main part of a tappet according to a second embodiment of the present invention. In this embodiment, a circular protrusion (14) having a required height is formed concentrically with the tappet body (7) at the center of the upper surface of the top wall (7a) of the tappet body (7) made of an aluminum alloy, The shape of the cam receiving plate (15) is a hat-shaped cross section that can be fitted to the circular projection (14), and the cam receiving plate (1
5) is placed on the top surface of the top wall (7a) so as to fit into the circular projection (14), and then, as in the above-described embodiment, the bent engagement piece (8a) of the coating tube (8). Thus, the engaging step (16) at the peripheral end of the cam receiving plate (15) is pressed.

A filler (11) is sealed in the gap between the tappet body (7), the covering cylinder (8) and the cam receiving plate (15) as described above.

The tappet (6) of this embodiment can be manufactured in the same manner as described above. The cam receiving plate (15) can be formed by pressing.

In the second embodiment, the same operation and effects as those of the first embodiment can be obtained, and the cam receiving plate is provided.
Since (15) is fitted to the circular projection (14), there is no possibility that the cam receiving plate (15) will be displaced laterally even if a large lateral pressure is applied by the cam.

FIG. 8 shows a tappet according to a third embodiment of the present invention. A tappet as a covering cylinder is provided on the entire outer peripheral surface of the same aluminum alloy tappet body (7) as in the first embodiment. Part (17a), and an externally thin (0.1-0.2 mm) outer cylinder (17) having an integral structure having a top plate (17b) as a cam receiving plate is fitted from above to form a cylindrical portion (17a). The lower end is plastically deformed inward to prevent it from falling off. The outer cylinder (17) is formed by deep drawing a cold-rolled steel sheet as described above.

The same filler (not shown) as described above is sealed in the gap between the tappet body (7) and the outer cylinder (17).

In the third embodiment, the same function and effect as described above can be obtained. Also, as described above, the cam receiving plate (9)
Since it is not necessary to separately manufacture the device, the cost can be reduced. The upper plate (17b) of the outer cylinder (17) may be subjected to a wear-resistant treatment such as carburization.

The present invention is not limited to the above embodiment. In the above embodiments, the tappet body
A filler (11) is sealed between (7) and the coating cylinder (8), the cam receiving plate (9), and the outer cylinder (17), but the surface of the tappet body (7) is smoothed. When the covering cylinder (8) or the outer cylinder (17) is fitted by press-fitting and no gap is formed between them and the tappet body (7), or when the tappet body (7) is made of plastic, When the material has a vibration absorbing property, the filling of the filler (11) may be omitted. In some cases, the chip (10) is omitted.

[0049]

According to the tappet of the first aspect, the tappet body is made of a non-ferrous material having a low specific gravity, and the covering cylinder and the cam receiving plate are made of thin metal. Significant measurement can be achieved. Further, the wear resistance of the outer peripheral surface of the tappet can be improved by simple means of merely mechanically fixing the coating cylinder without using thermal spraying, plating or the like, so that the manufacturing cost is greatly reduced.

According to the second aspect of the present invention, even if a large lateral pressure is applied to the cam receiving plate by the cam, there is no possibility that the cam receiving plate is displaced laterally.

According to the third aspect of the present invention, the effective surface area of the sliding surface of the upper surface of the tappet with the cam increases, so that the travel area of the cam also increases and the valve lift can be designed to be large.

According to the fourth aspect of the invention, in addition to the effect of the first aspect, since the upper surface plate as the cam receiving plate is formed integrally with the cylindrical portion, the number of steps for separately manufacturing the cam receiving plate is reduced. It is possible to save the cost and reduce the cost.

According to the fifth aspect of the present invention, the tappet body, the covering cylinder, and the cam receiving plate, and the tappet body and the outer cylinder,
Since the filler is firmly fixed as a binder and the filler absorbs vibration, mechanical noise generated from the tappet can be reduced. Further, since there is no need to apply a finishing process or the like to the surface of the tappet body to make it a smooth surface, the processing cost required for it is reduced.

According to the sixth aspect of the invention, since all the materials are lighter than iron, the tappet itself can be weighed.

According to the manufacturing method of the seventh aspect, the tappet main body, the coating cylinder and the cam receiving plate are integrated by simply fitting the coating cylinder into the tappet main body and bending the lower end portion inward. Since it can be fixed fixedly, productivity can be improved.

According to the eighth aspect of the present invention, the filler can be easily sealed in the gap between the tappet body, the covering cylinder and the cam receiving plate.

According to the ninth aspect of the present invention, the upper surface of the cam receiving plate can be covered by simply pressing and fitting the bent locking piece of the covering cylinder to the engaging step of the cam receiving plate from above. The upper surface of the tube can be easily aligned with the same surface.

According to the tenth aspect of the present invention, an extremely thin covering cylinder having a thickness of, for example, about 0.1 mm can be easily formed, and the inwardly bent locking piece at the upper end thereof can be easily formed at the same time. And it can contribute to weight reduction of the coating cylinder.

[Brief description of the drawings]

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

FIG. 2 is an enlarged view of a portion A in FIG.

FIG. 3 is an enlarged view of a portion B of FIG. 1;

FIG. 4 is a longitudinal sectional view showing a molding procedure of the coating cylinder.

FIG. 5 is a vertical cross-sectional view of each member before manufacturing showing the manufacturing method of the present invention.

FIG. 6 is a longitudinal sectional view after the tappet is manufactured.

FIG. 7 is an enlarged vertical sectional view of a main part showing a second embodiment of the tappet of the present invention.

FIG. 8 is a central longitudinal sectional front view showing the third embodiment.

FIG. 9 is a front view in the center longitudinal section of a conventional tappet.

[Explanation of symbols]

 (6) Tappet (7) Tappet body (7a) Top wall (7b) Chamfered part (8) Coated cylinder (8a) Bend locking piece (8b) Bottom wall (9) Cam receiving plate (10) Tip (11 ) Filler (12) Engagement step (13) Punch (14) Projection (15) Cam receiving plate (16) Engagement step (17) Outer cylinder (17a) Cylinder (17b) Top plate

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[Procedure amendment]

[Submission date] July 11, 2000 (2007.1.
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Name of invention

[Correction method] Change

[Correction contents]

Patent application title: Tappet for an internal combustion engine and a method for manufacturing the same

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G016 AA06 AA19 BB04 BB06 CA04 CA06 CA15 CA17 CA19 CA32 CA34 CA35 CA52 EA08 EA12 EA14 FA06 FA29 FA34 FA35 FA37 GA02

Claims (10)

[Claims] 1. A thin-walled cylindrical metal covering tube is fitted on the outer peripheral surface of a tappet body having a cylindrical shape with a low specific gravity and made of a non-ferrous material, and a hard metal material is attached to the top surface of the tappet body. A thin cam receiving plate is placed, the upper surface of the peripheral end of the cam receiving plate is pressed by bending the upper end of the coating cylinder inward, and the coating cylinder projects from the lower end of the tappet body. A tappet for an internal combustion engine, wherein an end portion is bent inward to thereby integrally fix a coating cylinder and a cam receiving plate to a tappet body. 2. A tappet for an internal combustion engine according to claim 1, wherein a circular projection is formed at the center of the top surface of the tappet body, and a cam receiving plate is fitted to the projection. 3. The cam receiving plate and the coating cylinder are provided with a downward engaging step on the upper surface of the peripheral end portion of the cam receiving plate where the inwardly bent portion at the upper end of the coating cylinder can be properly fitted. 3. The tappet for an internal combustion engine according to claim 1, wherein the upper surface is continuous with the same surface. 4. A thin metal outer cylinder having an upper surface plate connected to the upper end of a cylindrical portion is fitted from above onto the entire outer peripheral surface of a tappet body having a cylindrical shape with a low specific gravity and made of a non-ferrous material. A tappet for an internal combustion engine, wherein the outer cylinder is integrally fixed to the tappet body by bending inwardly a protruding end of the outer cylinder from the lower end of the tappet body. 5. The adhesive according to claim 1, wherein a solidifying filler having adhesiveness is sealed in a gap between the tappet body and the coating cylinder and the cam receiving plate or the outer cylinder. Tappet for internal combustion engine. 6. The tappet for an internal combustion engine according to claim 1, wherein the non-ferrous material having a low specific gravity is selected from an aluminum alloy, a magnesium alloy, a plastic, a ceramic, and a titanium alloy. 7. The method for manufacturing a tappet according to claim 1, wherein the tappet body is a topped cylindrical tappet made of a non-ferrous material having a low specific gravity, and can be fitted to an outer peripheral surface thereof. In addition, a thin-walled cylindrical metal covering tube having an inwardly bent bending piece at the upper end and a thin-walled hard metal cam receiving plate that can be placed on the top surface of the tappet body are separately formed in advance. In a state where the cam receiving plate is placed on the top surface of the tappet main body, the cover tube is fitted to the tappet main body with its bent-locking side facing upward, and the periphery of the cam receiving plate is An internal combustion system wherein the projecting end of the covering cylinder from the lower end of the tappet body is bent inward while the upper surface of the end is pressed by the bent locking piece to engage with the lower end of the tappet body. Manufacturing method of tappets for engines. 8. A solidifying filler having an adhesive property is placed on the top surface of the tappet body, and the filler is pressed when the cam receiving plate is pressed, so that the tappet body and the coating cylinder and the cam receiving plate are pressed. The method for manufacturing a tappet for an internal combustion engine according to claim 7, wherein the tappet is sealed in a gap between the tappets. 9. The tappet for an internal combustion engine according to claim 7, wherein an engagement step portion is provided on the upper surface of the peripheral end portion of the cam receiving plate so that the bent locking piece of the covering cylinder can be properly fitted from above. Manufacturing method. 10. A cold-rolled steel sheet is deep-drawn and formed into a cylindrical shape with a bottom, and then the bottom wall is punched into a circle with a slightly smaller diameter punch to form a coating cylinder. The peripheral end of the bottom wall of the remaining coating cylinder is formed as an inward bent locking piece.
The method for producing a tappet for an internal combustion engine according to any one of the above.