JP2536692Y2 - Tappet for internal combustion engine - 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 used for a direct-acting valve train in an internal combustion engine, and more particularly to a tappet that facilitates replacement of shims for adjusting valve clearance.

[0002]

2. Description of the Related Art FIG. 4 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 tappet (06) having a closed upper surface has an inner bottom surface of the circular upper wall (07) and a stem end of the engine valve (01). It is fitted from above so as to abut.

An annular side wall (0) connected to the upper part of the upper wall (07)
8), a dish-shaped recess (09) is formed inside the recess.
(09) 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) brought into contact with the upper surface of the shim (010).

[0006] In such a direct acting type valve operating mechanism, when adjusting the valve clearance, the tappet (06) is pushed down by an appropriate jig and the shim (010) having a different thickness is used. It is done by exchanging, but sim
The protrusion of the tappet (06) from the upper end of the (010) is small, the clearance of the fitting portion of the shim (010) is small, and the
0) and the upper surface of the upper wall (07) are in close contact with each other via the lubricating oil, and it is very difficult to remove them.

To solve this problem, tappets as shown in FIGS. 5 and 6 have been conventionally proposed. That is, in the conventional tappet shown in FIG. 5, a pair of slit-shaped notches opposed to each other at an interval of 180 ° in the circumferential direction are formed on an annular side wall (08) continuously provided above the upper wall (07). A groove (012) is formed, a screwdriver or the like is inserted into the cutout groove (012), and the shim (010) is extracted.

The tappet shown in FIG. 6 has a shim (010)
In a suitable place on the upper surface, a small-diameter through-hole (013) facing in the axial direction is vertically penetrated, and a rod-shaped extraction jig is inserted into this through-hole (013) to lift the shim (010), Alternatively, the shim (010) is drawn out by blowing compressed air through the through hole (013) to lift up the shim (010).

[0009]

In recent tappets, in order to further reduce the weight of the valve train, many tappets are made of a light alloy such as an aluminum alloy instead of the conventional iron such as a cast iron. Since the tappet made of light metal is inferior in strength and rigidity to that made of iron, if the cutout groove (012) is formed in the side wall (08) as in the conventional tappet shown in FIG. When a large outward repetitive load is applied to the side wall (08) due to improper movement of the valve train, stress concentrates on the notch groove (012) and cracks occur, or the side wall (08) is damaged Or may be.

On the other hand, the latter tappet shown in FIG.
In addition to the step of drilling a through hole (013) for removing the shim in (010), the shim (010) is
If it is in close contact with the vacuum (7), the removal jig inserted into the through-hole (013) slips and it takes time to remove the shim (010), or simply blows compressed air into the through-hole (013). In some cases, the shim (010) may not emerge.

Usually, the shim (010) is provided with a rotary cam (011).
Is rotated in a certain direction by a force acting at the time of rotation, which is orthogonal to the axis.
If the through hole (013) is drilled in (0), just when the drilled portion of the through hole (013) comes into contact with the nose surface of the rotating cam (011),
The surface pressure of the sliding surface of the shim (010) and the rotating cam (011) intermittently changes, and the surface pressure becomes higher than the surroundings.

As a result, local uneven wear may occur around the through hole (013) on the upper surface of the shim (010) and on the nose surface of the rotating cam (011), thereby impairing durability. The present invention has been made to solve the above problems, without reducing the strength and rigidity of the shim fitting portion and without causing uneven wear on the sliding surfaces of the shim and the rotating cam. It is an object of the present invention to provide a tappet for an internal combustion engine which enables a shim to be easily extracted.

[0013]

In order to achieve the above object, the present invention provides an annular side wall which is connected to the upper end of a cylindrical body whose upper surface is closed, and which is surrounded by the side wall. In a tappet, a shim for adjusting valve clearance is detachably fitted in the recessed portion, a concave groove of a required length is formed on the upper surface of the body, one end of which extends to the outer peripheral end of the body, An elastic push-up rod is fixed in one end of the push-up rod in the upper surface of the body in the concave groove, and the other end is formed in the side wall, and has a notch that faces in the vertical direction and communicates with the concave groove and the outside. It is characterized by being housed so as to be located in the part.

[0014]

The push-up rod having elasticity is housed in a concave groove formed on the upper surface of the body, and one end of the push-up rod is positioned in a notch formed in the side wall and facing the vertical groove communicating with the concave groove and the outside. As a result, the shim can be easily removed simply by pushing up one end of the push-up bar with an appropriate tool inserted from the notch.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. 1 and 2, a tappet (1) is a cylindrical body (2) formed of an aluminum alloy or the like.
And a disk-shaped shim (3) formed of a wear-resistant metal material such as gray cast iron or chromium molybdenum steel. The shim (3) is provided around the upper end of the upper wall (2a) of the body (2). It is detachably fitted into a recess (4) surrounded by a side wall (2b) provided continuously upward.

At the center of the upper surface of the upper wall (2a), a concave groove (5) oriented in a diametric direction perpendicular to the center axis of the body (2) has one end (the right end in FIG. 1) a side wall (2b). Through the body
It is formed so as to communicate with the outside of (2). Above groove
One end of (5) is continuous with a cutout groove (6) formed on a part of the side wall (2b) and facing up and down and having a width substantially equal to the groove width of the concave groove (5).

A resilient push-up bar 7 having a relatively small diameter such as a piano wire, an oil-tempered wire, a stainless steel wire or the like is inserted into one end portion (left end portion in FIG. 1) of the groove 5. To the body opposite to the notch groove (6) at the connecting corner of the side wall (2b).
By being press-fitted into the locking hole (8) formed at the upper end of (2), it is prevented from falling out and stored without play.

When the push-up bar (7) is accommodated in the groove (5), the upper end thereof is substantially flush with the upper end surface of the upper wall (2a) or slightly lower. . The other end of the push-up bar (7) is located in the concave groove (5) immediately below the cutout groove (6) and has a length that does not protrude from the outer peripheral surface of the body (2).

The outer peripheral surface of the upper end of the body (2) has a concave groove (5).
Further, a concave hole (9) connected to the notch groove (6) is formed such that its rear end face is located slightly deeper than the end face of the push-up bar (7).

When removing the shim (3), as shown in FIG. 3, first, the body (2) is pushed down by an appropriate jig,
After a required clearance is formed between the upper surface of (3) and the rotating cam (C), a rod-shaped tool (10) is inserted through the concave hole (9), and a push-up rod is inserted.
One end of (7) is pushed up toward the notch groove (6).

Then, the push-up bar (7) is elastically deformed upward with the press-fit portion into the locking hole (8) as a fulcrum.
The lower surface of the shim (3) is forcibly lifted. Therefore, sim
Even if (3) is in close contact with the upper wall (2a) via lubricating oil,
(4) The shim (3) can be removed more easily, and the shim (3) can be replaced quickly.

As described above, in the above embodiment, the shim (3) can be easily removed simply by pushing up one end of the push-up bar (7).
It is not necessary to form a through hole as in the prior art. Therefore, not only the step of forming a through hole in the shim (3) is omitted, but also the surface pressure of the sliding contact surface between the shim (3) and the rotary cam (C) changes or the surface pressure is reduced. There is no fear that it will increase locally,
Also, uneven wear does not occur on the sliding surfaces of the shim (3) and the rotating cam (C).

Further, since it is only necessary to form a cutout groove (6) having a minimum width allowing the upward movement of the push-up bar (7) in a part of the side wall (2b), the body (2) is made of an aluminum alloy. The strength and rigidity of the shim fitting portion do not decrease even if molded by the above method.

Instead of forming the cutout groove (6) as in the embodiment, a cutout hole (not shown) is formed in a part of the side wall (2b), which is continuous with the concave groove (5) and faces in the vertical direction. Then, the end of the push-up bar 7 may be moved up and down within the range of the notch hole.

With this configuration, the upper end of the side wall (2b) is continuous, which is advantageous in strength. The recess 9 can be omitted if a recess is formed in the end face of the push-up bar 7 on the side of the notch groove 6 so that the tip of the tool 10 can be hooked.

When fixing the end of the push-up bar 7 opposite to the cutout groove 6, the end is bent downward as shown by the imaginary line in FIG. 7a) may be pressed into a locking hole (not shown) formed in the upper wall (2a).

The push-up bar 7 may be made of a hard and elastic synthetic resin material or the like instead of using the above-mentioned metal material such as the piano wire.

[0028]

According to the present invention, the following effects can be obtained. (a) Since the shim can be easily and reliably extracted only by pushing up the push-up bar, it is not necessary to form a through hole in the shim as in the related art, and the processing process is simplified.

(B) Since the upper surface of the shim is a flat surface, there is no danger of uneven wear or the like occurring on the sliding surfaces of the shim and the rotating cam.

(C) Since there is no need to cut out the side wall as much as in the conventional case, the strength and rigidity of the shim fitting portion do not decrease even if the body is formed of an aluminum alloy or the like.

[Brief description of the drawings]

FIG. 1 is a front view of a central longitudinal section showing an embodiment of the present invention.

FIG. 2 is a longitudinal sectional side view of a main part along the line AA in FIG. 1;

FIG. 3 is an explanatory view showing a procedure for removing a shim.

FIG. 4 is a central longitudinal sectional front view schematically showing a direct-acting type valve operating mechanism to which the present invention is applied.

FIG. 5 is an exploded perspective view of a conventional tappet.

FIG. 6 is an exploded perspective view showing another example of the conventional tappet.

[Explanation of symbols]

(1) Tappet (2) Body (2a) Upper wall (2b) Side wall (3) Shim (4) Recess (5) Groove (6) Notch (notch) (7) Push-up bar (7a) Bend Part (8) Lock hole (9) Concave hole (10) Tool (C) Rotating cam

Claims (1)

(57) [Scope of request for utility model registration] 1. An annular side wall is provided upwardly at the upper end of a cylindrical body having a closed upper surface, and a shim for adjusting valve clearance is detachable in a recess surrounded by the side wall. In the fitted tappet, a concave groove of a required length is formed on the upper surface of the body so that one end side extends to the outer peripheral end of the body, and a push-up rod having elasticity is formed in the concave groove at one end thereof. For the internal combustion engine, which is fixed at a suitable position on the upper surface of the body, and is housed so that the other end is located in a notch formed in the side wall and facing the vertical direction communicating with the concave groove and the outside. Tappet.