JPH0589811U - Tappet for internal combustion engine - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] Easily pull out shims in internal combustion engine tappets without using a special pulling jig. [Structure] A disc spring (elastic member) 4 is housed in a concave hole (concave portion) 3 formed in the upper wall 2a of the upper end of the body 2, and the shim 6 is always biased upward. When the body 2 is pushed down to release the pressing load of the rotary cam C acting on the shim 6, the shim 6 is forcibly levitated by the repulsive force of the disc spring 4, so that the shim can be used without using a special jig. 6 can be easily removed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a tappet used for a direct-acting valve operating mechanism in an internal combustion engine, and more particularly to a tappet that facilitates replacement of a shim for valve clearance adjustment.

[0002]

[Prior Art]

 FIG. 4 schematically shows a direct-acting valve operating mechanism that is widely used in DOHC engines. Therefore, the engine valve (01) includes a pair of cotters (02) (02), a spring retainer (03), It is attached to the cylinder head (05) by a valve spring (04) and the like.

At the upper end of the engine valve (01), there is a cylindrical tappet (06) whose upper surface is closed, and the inner bottom surface of the circular upper wall (07) serves as the stem end of the engine valve (01). It is inserted from above so that it abuts.

A disc-shaped recess (09) is formed inside the annular side wall (08) connected to the upper part of the upper wall (07), and a valve is provided in this recess (09). A clearance adjustment shim (010) is fitted.

In the engine valve (01), the entire tappet (06) guided by the cylinder head (05) is pushed by the rotating cam (011) brought into contact with the upper surface of the shim (010). Can be opened and closed.

In such a direct-acting type valve operating mechanism, when the valve clearance is adjusted, the tappet (06) is pushed downward by an appropriate jig, and the shim (010) having a different thickness is used. However, the shim (010) has a smaller protrusion from the top of the tappet (06), and the gap between the shim (010) and the shim (010) is smaller. It is very difficult to remove it because the upper surface of the upper wall (07) is in close contact with it via the lubricating oil.

In order to solve this problem, conventionally, tappets as shown in FIGS. 5 and 6 have been proposed. That is, the conventional tappet shown in FIG. 5 has a pair of slotted notches facing each other at an interval of 180 ° in the circumferential direction on an annular side wall (08) continuously provided on the upper wall (07). A groove (012) is formed, a driver or the like is inserted into the notch groove (012), and the shim (010) is pulled out.

Further, the tappet shown in FIG. 6 has a small diameter through hole (013) which is oriented in the axial direction and vertically penetrates through the shim (010) at an appropriate position, and the through hole (013) has a rod shape. The shim (010) is pulled out by inserting the extraction jig of the above and lifting the shim (010), or by blowing the compressed air from the through hole (013) to lift the shim (010). Is.

[0009]

[Problems to be solved by the device]

 For the purpose of further reducing the weight of valve trains, recent tappets are often made of light alloys such as aluminum alloys in place of the conventional iron such as cast irons. Since light metal tappets are inferior in strength and rigidity to iron ones, if the notch groove (012) is formed in the side wall (08) like the conventional tappet shown in FIG. When the valve train has an improper movement and a large outward cyclic load is applied to the side wall (08), stress is concentrated in the notch groove (012) and cracks occur, or the side wall (08) It may be damaged.

On the other hand, the latter tappet shown in FIG. 6 not only needs a step of forming the through hole (013) in the shim (010), but also blows compressed air with an air gun or the like each time, and has a rod shape. Since it is necessary to use an extraction jig, it is troublesome to replace the shim. Also, if the shim (010) is in vacuum contact with the upper wall (07) through the oil film, the extraction jig inserted into the through hole (013) will slip and it will take time and trouble to remove it. The shim (010) may not be lifted simply by blowing compressed air into the 013).

The present invention has been made to solve the above-mentioned problems, and the shim can be easily removed without lowering the strength and rigidity of the shim fitting portion or using a special extraction jig. The purpose of the present invention is to provide a tappet for an internal combustion engine that enables quick replacement work of shims.

[0012]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a cylindrical body whose upper surface is closed with an annular side wall upwardly connected to the upper end of the body, and a valve clearance adjustment is provided in a recess surrounded by the side wall. In a tappet that is detachably fitted with a shim for use in the body, a concave portion is formed in an appropriate place on the upper surface of the body, and the concave portion is constantly urged upward by contacting the lower surface of the shim. It is characterized by containing an elastic member that

[0013]

[Action]

 The elastic member is housed in the recess formed on the upper surface of the body so that the shim is always urged upward, so that when the body is pushed down and the pressing load of the rotating cam acting on the shim is released, Since the shim is forcibly levitated by the repulsive force of the elastic member, the shim can be easily pulled out without using a special jig.

[0014]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a tappet (1) according to a first embodiment of the present invention, in which a body (2) is made of aluminum alloy or the like and is formed in a cylindrical shape with its upper surface closed, and its upper wall (2a An annular side wall (2b) is continuously provided as an upward direction around the upper end of ().

A circular and bottomed concave hole (3) coaxial with the axis of the body (2) is formed in the center of the upper surface of the upper wall (2a). A disc spring (4) is loosely inserted into the recessed hole (3) such that the upper end of the disc spring (4) slightly protrudes from the upper end surface of the upper wall (2a) in the unloaded state.

In the recess (5) surrounded by the side wall (2b) of the body (2), a disc-shaped shim (6) made of wear-resistant metal material such as gray cast iron and chrome molybdenum steel is attached and detached. Fitted as possible.

(7) is a relief groove for polishing the upper surface of the upper wall (2a). When the tapette (1) of the above embodiment is assembled to the engine as shown in FIG. 4, the rotating cam (C) pushes down the shim (6) while bending the disc spring (4), An upward biasing force of the disc spring (4) always acts on the shim (6). At the time of this pressing, a very small gap for the valve clearance is formed between the facing surfaces of the shim (6) and the upper wall (2a).

In the tappet (1) of the first embodiment described above, in order to replace the shim, the body (2) is pushed down by an appropriate jig to press the rotary cam (C) acting on the shim (6). When the load is released, even if the shim (6) is in close contact with the upper wall (2a) through the lubricating oil, the shim (6) is forced to levitate due to the elastic restoring force of the disc spring (4). .

Therefore, it is possible to easily pull out the shim (6) with a finger, a magnet or the like without providing the body (2) or the shim (6) with a notch groove or a through hole for taking out the shim unlike the conventional case. .

FIG. 3 shows a second embodiment of the present invention. In this embodiment, an annular groove (8) having a relatively large diameter is formed on the upper surface of the upper wall (2a), and the recess is formed. A large-diameter disc spring (9) is loosely inserted in the groove (8) such that the upper end thereof slightly projects from the upper end surface of the upper wall (2a).

The second embodiment also has the same actions and effects as those of the first embodiment, and the large-diameter disc spring (9) has a fitting portion at the peripheral end of the shim (6). Since it is in contact with the vicinity, the shim (6) can be lifted more stably without tilting.

In the first embodiment, instead of the disc spring (4), a compression coil spring, a leaf spring having a V shape or a V shape, or an elastic body such as hard rubber may be used. Good.

[0023]

[Effect of the device]

 The following effects can be obtained by selecting the present invention. (a) The shim can be forcibly lifted by simply pushing down the body without using a special extraction jig, so that the replacement work of the shim is quick and efficient.

(B) Since it is not necessary to cut out the side wall as in the conventional case, even if the body is molded of aluminum alloy or the like, the strength and rigidity of the shim fitting portion are not reduced.

[Brief description of drawings]

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

FIG. 2 is an exploded perspective view of the same.

FIG. 3 is a central longitudinal front view showing a second embodiment of the present invention.

FIG. 4 is a central vertical 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 showing 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) Recessed hole (recessed part) (4) Disc spring (elastic member) (5) Recessed part (6) Shim (7) Relief groove ( 8) Recessed groove (recessed portion) (9) Disc spring (elastic member) (C) Rotating cam

Claims (2)

[Scope of utility model registration request] 1. A ring-shaped side wall is continuously provided upwardly on an upper end portion of a cylindrical body whose upper surface is closed, and a shim for adjusting a valve clearance is detachable in a recess surrounded by the side wall. In the fitted tappet, a recessed portion is formed at an appropriate place on the upper surface of the body, and the recessed portion,
A tappet for an internal combustion engine, characterized in that an elastic member which constantly urges the shim upward by contacting the lower surface of the shim is housed. 2. The tappet for an internal combustion engine according to claim 1, wherein the elastic member is a disc spring.