JP2807943B2 - Tappet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tappet for use in a direct-acting type valve operating mechanism, in which a shim for adjusting a valve clearance is easily taken out.

[0002]

2. Description of the Related Art FIG. 5 schematically shows a direct-acting type valve operating mechanism frequently used in a DOHC type engine. An engine valve (01) includes a pair of cotters (02) and (02) and a spring. Cylinder head by retainer (03), valve spring (04), etc.
(05).

[0003] At the upper end of the engine valve (01), a cylindrical iron tappet (06) whose upper surface is closed is attached to the lower end of the circular upper wall (07) by the stem end of the engine valve (01). And is inserted from above so as to abut against it.

An annular side wall (0) connected to the upper part of the upper wall (07)
Inside (8), a circular recess (09) is formed, and this recess (0) is formed.
9) is fitted with a shim (010) for adjusting the valve clearance.

The engine valve (01) has a cylinder head (0)
The entire tappet (06) guided by 5) is opened and closed by being pushed by the rotating cam (011) in contact with the upper surface of the shim (010).

In such a direct acting type valve operating mechanism, the valve clearance is adjusted by replacing the tappet (06) with a shim (010) having a different thickness in a state where the tappet (06) is pressed down by an appropriate jig. But the shim (010) and the upper wall (07)
Is in close contact with the upper surface via the lubricating oil, so that the removal is troublesome.

Therefore, as shown in FIG. 6, the conventional tappet (06) has an annular side wall (08) connected to the upper part of the upper wall (07).
A pair of slit-shaped notches (012) are formed at intervals of 180 ° in the circumferential direction, and a screwdriver or the like is inserted into the notches (012) to remove the shim (010). I have to.

[0008]

Recently, the demand for higher rotation and higher output of the engine has been required to further reduce the weight of the valve train, and tappets have been changed from conventional iron to aluminum alloy. There is a tendency to move.

The tappet made of aluminum alloy is inferior in strength and rigidity to that of iron. In the valve system, irregular movement occurs,
When a strong outward load is applied to the side wall (08), the notch groove
Stress may concentrate on the (012) portion, and the side wall (08) may be damaged.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the shim can be easily replaced without lowering the strength and rigidity of a shim fitting portion formed by the recess and the side wall. It is an object to provide a tappet that can be obtained.

[0011]

According to the present invention, the above-mentioned problem is solved as follows. (1) A tappet in which a disc-shaped shim for adjusting valve clearance is detachably fitted into a recess formed at the upper end of a cylindrical body having a closed upper surface. 0.08mm maximum width between the peripheral surface and the outer peripheral surface of the shim
A gap of about 0.15 mm is provided. (2) A tappet in which a disc-shaped shim for adjusting valve clearance is detachably fitted into a recess formed at the upper end of a cylindrical body whose upper surface is closed. A hard synthetic resin layer is provided on the peripheral surface, and a gap is provided between the inner peripheral surface of the hard synthetic resin layer and the outer peripheral surface of the shim.

[0012]

When compressed air is blown into the gap between the inner peripheral surface of the recess formed at the upper end of the body and the outer peripheral surface of the shim using the tappet of the present invention, the compressed air loses its escape area, and Since the compressed air that has entered the bottom surface of the place causes the shim to float from the recess, the shim can be easily removed from the recess. At this time, by setting the maximum width of the gap to the condition described in claim 1, according to experiments, the compressed air acts most efficiently, and the shim can be easily removed from the recess.

Further, when a hard synthetic resin layer is provided on the inner peripheral surface of the recess, the shim moves in the left-right direction by the rotating cam and collides with the inner peripheral surface of the recess. Abrasion and rattling noise generated by the vibration can be reduced.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the tappet according to the present invention.
In the embodiment, a tappet (1) includes a cylindrical body (2) formed of a light alloy such as an aluminum alloy,
The shim (3) is made of an iron disk-shaped shim (3), and the shim (3) is an annular side wall (2b) continuously connected upward to an upper part of an upper wall (2a) closing an upper end of the body (2). )
It is detachably fitted in (4).

The outer diameter of the shim (3) is smaller than the inner diameter of the side wall (2b), so that the shim (3) and the inner peripheral surface (4a) of the recess (4) are
A recess from the upper end of the shim (3) between the outer peripheral surface (3a) of (3)
A gap (5) connected to the bottom surface (4b) of (4) is formed. The maximum width (L ₁ ) of the gap (5) is 0.08 mm to 0.15 mm.

According to the tappet of the present invention, it is not necessary to cut out the side wall (2b) as in the prior art. Therefore, even if the body (2) is formed of an aluminum alloy or the like, the recess (4) and the side wall (2b) are not cut out.
The strength and rigidity of the shim fitting portion formed from (2b) do not decrease.

Next, the procedure for removing the shim when the tappet is used will be described with reference to FIG. In FIG.
The tappet (1) is the same as that shown in FIG.

A gap formed between the inner peripheral surface (4a) of the recess (4) and the outer peripheral surface (3a) of the shim (3) in the tappet (1).
Hold the air gun (6) from diagonally above (5),
Compressed air spouting from the tip of (6) is blown into the gap (5). Then, the compressed air does not lose its escape, the gap (5)
In addition to blowing out the lubricating oil that has entered between the bottom surface (4b) of the recess (4) and the lower surface (3b) of the shim (3), the bottom surface (4b) of the recess (4) and the shim (3) The compressed air enters between the lower surface (3b) and the shim (3), so that the shim (3) can be easily removed from the recess (4).

FIG. 3 shows another example of the procedure for removing the shim. A vertical groove extending outward from the inner peripheral surface of the recess (4) of the tappet (1) and extending from the upper end to the lower end of the side wall.
(8), and a gap (5 ') formed by the vertical groove (8).
By blowing the compressed air of the air gun (6) in the same manner as shown in FIG. 2, the compressed air loses its escape area and the shim (3) floats, and the shim (3) is recessed. It can be easily removed from the place.

The other structure of the tappet (1) is the same as that shown in FIG. 1, and these are denoted by the same reference numerals, and detailed description is omitted. The flute
(8) may be provided on the outer peripheral surface of the shim (3) so as to be recessed inward.

Since the side wall (2b) is continuous, even if it is formed of a lightweight material such as aluminum, the recess (4) and the side wall (2b)
The strength and rigidity of the shim fitting portion formed by (2b) does not decrease.

Next, an embodiment of the tappet according to claim 2 will be described with reference to FIG. The same members as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description is omitted.

In this tappet (1), a recess (6) for an oil sump is provided substantially at the center of the bottom surface (4b) of the recess (4), and the recess (4) is provided.
A hard synthetic resin layer (7) is provided on the inner surface (4a) of (4).

By providing the recess (6) for the oil sump,
The lubricating oil that has entered through the gap (5) has good oil retention, and even if the shim (3) is rotated by the rotation of a rotating cam (not shown), the lubricating oil stored in the concave portion (6) causes The rotation of the shim (3) becomes smooth and the shim (3)
Wear of the contact surface between the body and the body (2) is reduced. Further, since the compressed air enters the concave portion (6), the shim (3) easily floats.

Further, since a hard synthetic resin layer (7) is provided on the inner peripheral surface (4a) of the recess (4) by coating or by integral molding, etc., the shim (3) is left and right by a rotating cam. In this case, the abrasion and rattling noise generated by moving in the direction and colliding with the inner peripheral surface (4a) of the recess (4) are reduced. In this embodiment, the shim can be taken out in the same manner as shown in FIG.

As described above, according to the tappet of the present invention, if the compressed air is simply blown into the gap, the shim floats easily, so that the shim can be easily removed from the recess, and the shim can be replaced. It will be easier.

Further, since a gap is provided between the inner peripheral surface of the recess and the outer peripheral surface of the shim instead of the conventional notch groove, the strength and rigidity of the shim fitting portion are not reduced.

[0028]

(A) According to the present invention, a gap communicating from the upper end face of the shim to the bottom face of the recess is provided between the inner peripheral face of the recess and the outer peripheral face of the shim. When the compressed air is blown into the shim, the compressed air loses a place to escape and the shim floats, and the shim can be easily pulled out from the recess, and the shim can be easily replaced.

(B) Since the tappet does not need to be cut off in the side wall as in the prior art, the strength of the shim fitting portion formed by the recess and the side wall even when the body is formed of an aluminum alloy or the like. There is no fear that the rigidity is reduced.

(C) By setting the gap between the inner peripheral surface of the recess and the outer peripheral surface of the shim as the condition of claim 1, the compressed air acts efficiently and the shim is most easily removed. Can be removed from the recess. Further, by providing a hard synthetic resin layer on the inner peripheral surface of the recess as described in claim 2, abrasion and rattling noise can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the tappet of the present invention described in claim 1.

FIG. 2 is a perspective view showing a procedure for removing a shim from the tappet of FIG. 1;

FIG. 3 is a perspective view showing another example of a shim removal procedure in the tappet of FIG. 1;

FIG. 4 is a longitudinal sectional view showing an embodiment of the tappet of the present invention described in claim 2;

FIG. 5 is a longitudinal sectional view showing a conventional valve train.

FIG. 6 is an exploded perspective view of a conventional tappet.

[Explanation of symbols]

 (1) Tappet (2) Body (2a) Upper wall (2b) Side wall (3) Shim (3a) Outer peripheral surface (3b) Lower surface (4) Recess (4a) Inner peripheral surface (4b) Bottom surface (5) (5 ') Gap (6) Air gun (7) Synthetic resin layer (8) Vertical groove (8a) Opening

Claims (2)

(57) [Claims] To 1. A recess having an upper surface formed on the upper end of the body having a cylindrical shape which is closed, in a tappet formed by fitting the disc-shaped shims for adjustment valve clearance detachably said recess Between the inner peripheral surface of the
A gap having a width of 0.08 mm to 0.15 mm.
Pets To 2. A recess having an upper surface formed on the upper end of the body having a cylindrical shape which is closed, in a tappet formed by fitting the disc-shaped shims for adjustment valve clearance detachably recess With a hard synthetic resin layer on the inner peripheral surface of
Between the inner peripheral surface of the hard synthetic resin layer and the outer peripheral surface of the shim.
A tappet characterized by providing a gap in the tappet.