JP2000045718A - Tappet for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower the noise in a tappet provided with a shim in a recessed hole provided in a top surface of a top wall of a cylindrical tappet main body having a bottom by providing at least one of the top wall of the tappet main body and a surface of the tappet main body opposite to the shim with a vibration control plate formed by fixing a board and a restricting board to an upper and a lower viscous and elastic material surfaces. SOLUTION: A tappet main body 4 made of the aluminum alloy is formed with a circular recessed part 9 in a top surface of a top wall 4a thereof, and a vibration control board 10 is fitted in the recessed part 9 so that the top surface of the vibration control board 10 contacts with a lower surface of a shim 6. The vibration control board 10 is formed by pinching a viscous and elastic material 11 with a lower board 12 and an upper board 13 like a sandwich, and the board 12 is fitted in the bottom surface of the recessed part 9 so as to be integrally provided with the tappet main body 4. As the viscous and elastic material 11, butyl group hard rubber and vinyl chloride having excellent vibration energy absorbing property can be used, and as the board 12 and the restricting board 13, a thin steel plate, a light metal plate such as aluminum alloy, and a hard synthetic resin plate can be used.

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 direct-acting valve train in an internal combustion engine.
The present invention relates to a tappet capable of reducing noise due to vibration.

[0002]

2. Description of the Related Art FIG. 6 schematically shows a direct-acting type valve operating mechanism in an internal combustion engine. A cylinder head (1) includes a valve spring, a spring retainer and the like (both not shown).
Thus, the engine valve (2) is assembled.

The tappet (3) has a cylindrical tappet body (4) with a closed top and a concave hole in the top surface of the top wall (4a).
It consists of a shim (6) detachably fitted in (5) and a small-diameter chip (7) fitted in the center of the lower surface of the top wall (4a), the lower surface of the chip (7) being the engine. The guide hole (1) of the cylinder head (1) is brought into contact with the shaft end of the valve (2).
It is slidably fitted to a). A cam (8) comes into contact with the upper surface of the shim (6) with a required valve clearance.

[0004]

The main noises generated by the direct-acting valve mechanism described above include friction and friction when the nose of the cam (8) slides on the upper surface of the shim (6). Impact sound, impact sound when the engine valve (2) is seated on a valve seat (not shown), vibration sound of a valve spring (not shown), and when the tappet (3) slides in the guide groove (1a) There are friction and slap sounds, etc., and most of these noises are emitted via the tappet (3). That is, the tappet body (4), the shim (6) and the tip constituting the tappet (3)
Because (7) is made of metal, it is hardly attenuated when vibration is applied to these, and resonates.

[0005] In order to reduce the noise generated from the tappet (3), the weight of the valve train, the profile of the cam (8) is changed, the tappet (3) and the guide hole (1a) are reduced.
It is effective to reduce the load on the tappet (3) by minimizing the gap between the sliding surfaces of the tappet and the like.

However, considering the cost, engine performance, reliability, etc., there is a limit to the above-mentioned noise countermeasures. Therefore, no measures have been taken as noise generated from the tappet is inevitable. It is.

The present invention has been made in view of the above problems, and effectively reduces and attenuates vibrations applied to a tappet body by effectively absorbing and attenuating the vibrations.
It is an object of the present invention to provide a tappet capable of obtaining a quiet valve train.

[0008]

According to the present invention, the above-mentioned problem is solved as follows. (1) A tappet for an internal combustion engine comprising a tappet main body having a cylindrical shape with a top and a shim fitted into a concave hole on the upper surface of the top wall. At least one of them is provided with a vibration damping ply plate in which a substrate and a restraining plate are fixed to upper and lower surfaces of a viscoelastic material, with the substrate side fixed to a top wall or a shim.

(2) A tappet body having a cylindrical shape with a top,
In a tappet for an internal combustion engine comprising a shim fitted in a concave hole on the upper surface of the top wall, at least one of opposing surfaces of the tappet body and the top wall and the shim is provided with one of upper and lower viscoelastic materials. A damping plywood having a restraining plate fixed to one surface is provided by fixing a viscoelastic material to a top wall or a shim.

(3) In the above item (1) or (2), the damping plywood is also fixed to the lower surface of the top wall.

(4) In the above item (3), the damping plywood is formed in a downward cup shape and is fixed to the inner peripheral surface of the cylindrical portion of the tappet body.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. The same members as those in the conventional example described above are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 shows a first embodiment of the first aspect of the present invention, wherein a tappet body (4) made of an aluminum alloy is provided.
In the circular concave portion (9) formed on the upper surface of the top wall (4a), a vibration damping plywood (10) is fitted so that the upper surface thereof contacts the lower surface of the shim (6). .

The damping plywood (10) is a disk-shaped viscoelastic material (11)
Is sandwiched between the lower substrate (12) and the upper restraint plate (13), and the substrate (12) is recessed (9).
Is provided integrally with the tappet body (4) by being fixed to the bottom surface of the tappet.

As the viscoelastic material (11), for example, butyl hard rubber, vinyl chloride,
Vinyl acetate polymers, epoxy resins and the like are preferred.

As the substrate (12) and the restraint plate (13), a thin steel plate, a light metal plate such as an aluminum alloy, a hard synthetic resin plate or the like is suitable.

As in the first embodiment, the tappet body
When the vibration damping plywood (10) is fixedly provided on the upper surface of the top wall (4a) in (4), particularly, the vertical vibration of the top wall (4a) of the tappet body (4) accompanying the valve movement is provided. Is effectively absorbed.

That is, when vibration is applied to the top wall (4a), a phase difference of bending is generated between the substrate (12) and the restraint plate (13) via the viscoelastic material (11), so that the viscoelasticity is increased. Shear deformation resistance (shear resistance) is generated in the material (11), and thereby a large vibration damping effect is obtained. As a result, the vibration energy of the top wall (4a) is absorbed, and the noise emitted from the tappet (3) is reduced.

FIG. 2 shows a second embodiment of the present invention. In this embodiment, on the contrary, an upward concave portion (14) is formed on the lower surface of the shim (6), and the viscoelastic material (11) and the substrate (12) are formed in the concave portion (14) as described above. And a damping plywood (10) composed of a restraining plate (13). In this example,
The substrate (12) is fixed in the recess (14) of the shim (6) with the substrate (12) facing upward.

As in the second embodiment, even if the damping plywood (10) is provided on the shim (6) side, the top wall (4a) of the tappet body (4) is operated in the same manner as in the first embodiment. ) To the shim (6) is effectively absorbed and attenuated,
As described above, the noise emitted from the tappet (3) is reduced.

FIG. 3 shows an embodiment of the second aspect of the present invention. In this embodiment, the vibration damping plywood (15) is made of a disc-shaped viscoelastic material (11) having a smaller diameter than the concave hole (5) of the tappet body (4).
And the restraint plate (13) fixed to the upper surface thereof, by omitting the substrate (12) as described above, and fixing the viscoelastic material (11) to the upper surface of the top wall (4a). , Tappet body
It is provided integrally with (4).

The shim (6) is configured such that an upward concave portion (14) formed on the lower surface thereof is fitted to the damping plywood (15).
It is detachably mounted in the concave hole (5).

In this embodiment, the top wall (4a) is
Performs the same operation as (12), a bending phase difference is generated between the top wall (4a) and the restraint plate (13), and shear deformation resistance occurs in the viscoelastic material (11). Thus, the vibration energy of the top wall (4a) is absorbed, and the noise generated from the tappet (3) can be reduced.

Although not shown, the damping plywood (15) may be turned upside down and fixed to the shim (6).

FIG. 4 shows an embodiment of the third aspect of the present invention. In this embodiment, similar to the embodiment shown in FIG.
Vibration damping plywood (15) consisting of viscoelastic material (11) and restraint plate (13),
A viscoelastic material is placed on the lower surface of the top wall (4a) excluding the fitting part of the chip (7).
By fixing (11), it is provided integrally with the tappet body (4).

In this embodiment, the same operation and effect as described above can be obtained.

FIG. 5 shows an embodiment of the invention according to claim 4, wherein the damping plywood (16) of this embodiment is obtained by deforming the damping plywood (15) shown in FIG. The viscoelastic material (11) is formed in a cup shape and fixed to the lower surface of the top wall (4a) and the upper part of the inner peripheral surface of the cylindrical portion continuous therewith. (13) is a restraint plate.

Also in this embodiment, the same function and effect as described above can be obtained, and a part of the vibration damping plywood (16) is extended to the upper part of the inner peripheral surface of the cylindrical portion.
It has the function of absorbing not only the vertical vibration of (4) but also the horizontal vibration.

In the embodiment shown in FIG. 5, the damping plywood (16) may be provided on the entire inner peripheral surface of the cylindrical portion of the tappet body (4). In this case, the tappet (3) is provided.
Is undesirably increased in weight and the inertial mass is increased.

The present invention is not limited to the above embodiment. In the embodiment shown in FIGS. 1 and 2 and FIGS. 3 and 4, the damping plywoods (10) and (15) are respectively attached to the top wall (4a).
Although it is provided only on one of the surface facing the shim (6) and the upper and lower surfaces of the top wall (4a), it may be provided on both of them. In this case, in order to minimize the weight increase of the tappet (3), the thickness of the damping plywood (10) (15) is preferably reduced.

The present invention can be applied not only to the tappet (3) in which the tappet body (4) is formed of an aluminum alloy, but also to a magnesium alloy, a titanium alloy, or an ordinary iron tappet.

[0032]

(A) According to the first aspect of the present invention, the vibration of the tappet body and the shim is absorbed and attenuated by the damping plywood, so that the noise generated thereby is reduced, and the quiet valve operating system is provided. Is obtained.

(B) According to the second aspect of the present invention, in addition to the above effects, the weight of the tappet can be reduced due to the absence of the substrate.

(C) According to the third aspect of the invention, the noise emitted from the tappet is further reduced.

(D) According to the fourth aspect of the invention, the vibration of the cylindrical portion of the tappet body can also be absorbed and attenuated.

[Brief description of the drawings]

FIG. 1 is a front view of a main portion of a valve train to which a first embodiment of the invention is applied, taken along a central longitudinal section.

FIG. 2 is a central longitudinal front view of a main part of a valve mechanism to which a second embodiment is applied.

FIG. 3 is a longitudinal sectional front view of an essential part showing an embodiment of the invention described in claim 2;

FIG. 4 is a longitudinal sectional front view of an essential part showing an embodiment of the invention described in claim 3;

FIG. 5 is a longitudinal sectional front view of an essential part showing an embodiment of the invention described in claim 4;

FIG. 6 is a central longitudinal sectional front view of a main part of a valve train including a conventional tappet.

[Explanation of symbols]

 (1) Cylinder head (1a) Guide hole (2) Engine valve (3) Tappet (4) Tappet body (4a) Top wall (5) Concave hole (6) Shim (7) Tip (8) Cam (9) ( 14) recess (10) (15) (16) damping plywood (11) viscoelastic material (12) substrate (13) restraint plate

Claims (4)

[Claims] 1. A tappet for an internal combustion engine comprising a tappet body having a cylindrical shape with a top and a shim fitted in a concave hole on the upper surface of the top wall, wherein the top wall and the shim of the tappet body face each other. At least one of the surfaces is provided with a vibration damping ply plate in which a substrate and a restraining plate are fixed to the upper and lower surfaces of a viscoelastic material, and the substrate side is fixed to a top wall or a shim. Tappet. 2. A tappet for an internal combustion engine, comprising a tappet body having a cylindrical shape with a top and a shim fitted into a concave hole on the upper surface of the top wall, wherein the top wall and the shim of the tappet body face each other. Internal combustion characterized in that at least one of the surfaces is provided with a vibration damping plywood in which a restraining plate is fixed to one of upper and lower surfaces of a viscoelastic material, and the viscoelastic material is fixed to a top wall or a shim. Institutional tappet. 3. The tappet for an internal combustion engine according to claim 1, wherein the damping plywood is also fixed to the lower surface of the top wall. 4. The tappet for an internal combustion engine according to claim 3, wherein the damping plywood has a downward cup shape and is fixed to an inner peripheral surface of a cylindrical portion of the tappet body.