JPH0592405U - Tappet for internal combustion engine - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To provide a tappet for an internal combustion engine that enables the shim to be easily pulled out without reducing the strength and rigidity of the fitting portion of the shim. [Structure] A stepped hole 5 having an opening area on the lower side larger than that on the upper side is formed at an appropriate position of a shim 3 which is detachably fitted in a recess at an upper end portion of a body 2. 5
A step portion is formed inside, and if a hooking piece 6a of an appropriate extraction tool 6 is hooked and pulled up on this step portion, the shim 3 can be easily pulled out from the recess without the tool 6 slipping.

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. 3 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 shim (010) and the upper surface of the upper wall (07) are in close contact with each other via lubricating oil. Therefore, it is very difficult to remove it.

To solve this problem, conventionally, tappets as shown in FIGS. 4 and 5 have been proposed. That is, the conventional tappet shown in FIG. 4 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.

The tappet shown in FIG. 5 has a small-diameter through hole (013) which is oriented in the axial direction and vertically penetrates the upper surface of the shim (010) at a proper position, and the through hole (013) has a rod-like 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 instead of cast iron or other iron. Light alloy tappets are made of iron. Since the strength and rigidity are inferior compared to the conventional tappet shown in FIG. 4, when the notch groove (012) is formed in the side wall (08), the valve operating system causes improper movement when the engine rotates at high speed. However, when a large outward repeated load is applied to the side wall (08), stress may be concentrated in the notch groove (012) to cause a crack or the side wall (08) may be damaged.

On the other hand, like the latter tappet shown in FIG. 5, when the through hole (013) is simply formed in the shim (010), the shim (010) is evacuated to the upper wall (07) through the oil film. If they are in close contact with each other, the rod-shaped extraction jig inserted in the through hole (013) may slip, and it may take time to extract.In addition, if compressed air is blown into the through hole (013), it may be removed. Sometimes there is not.

The present invention has been made to solve the above-mentioned problems, and allows the shim to be easily removed and the shim replacement work to be performed quickly without reducing the strength and rigidity of the shim fitting portion. It is an object of the present invention to provide a tappet for an internal combustion engine, which is made possible.

[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, a stepped hole having an opening area on the lower side larger than that on the upper side is formed in the thickness direction at an appropriate position of the shim. I am trying.

[0013]

[Action]

 A stepped hole is formed in the stepped hole by forming a stepped hole with an opening area on the lower side larger than that on the upper side at an appropriate position of the shim that is detachably fitted to the upper end of the body. By hooking the tip of an appropriate tool on the step and pulling it up, the shim can be easily pulled out from the recess without the tool slipping.

[0014]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a first embodiment of the present invention, in which a tappet (1) is composed of a cylindrical body (2) formed of an aluminum alloy or the like, gray cast iron, chrome molybdenum steel or the like. It consists of a disc-shaped shim (3) formed of a wear-resistant metallic material, and the shim (3) is provided on the upper wall (2a) of the body (2) around the upper end of the side wall (2b). ), It is removably fitted in the recess (4).

At a position near the outer peripheral end of the shim (3), that is, at a position deviated from a sliding contact surface with a rotating cam (not shown), a rectangular long hole (5a) formed in an upper half portion and a lower hole (5a) are formed. The stepped hole (5) consisting of the long hole (5 a) formed in the half part and the continuous circular hole (5 b) has a vertical ( The plate is formed so as to face the (thickness) direction.

The shim (3) can be extracted from the recess (4) by using a T-shaped extraction tool (6) as shown in FIG. 2, for example. That is, the prismatic hooking piece (6a) fixed to the lower end of the tool (6) is inserted into the circular hole (5b) through the long hole (5a) of the stepped hole (5), and then the tool (6). Rotate the whole by 90 ° in either direction.

In this state, if the extraction tool (6) is pulled up or tilted to the side, the hook piece (6a) is hooked on the step formed in the stepped hole (5), and the shim (3 ) Can be easily removed from the recess (4).

FIG. 3 shows a second embodiment of the present invention. In this embodiment, a stepped hole (5) similar to the one described above is provided separately on the opposite side facing 180 ° with the upside down direction. It was set up.

By thus forming the two stepped holes (5), even if the shim (3) is fitted in the recess (4) in the upside-down direction, either one of the stepped holes is formed. The shim (3) can be removed by using the holes, so it is not necessary to consider the top and bottom of the shim when assembling or replacing the shim, and the other surface can be removed when one surface is worn. There are advantages that can be used.

As described above, in the first and second embodiments, since the stepped hole (5) is formed in the shim (3), the extraction tool slips as in the conventional case. Even if the shim (3) is in close contact with the upper wall (2a) in a vacuum state, it can be easily removed by using the extraction tool (6).

Moreover, since it is not necessary to cut out the side wall (2b) as in the conventional case, even if the entire body (2) is molded with aluminum alloy or the like, the strength and rigidity of the shim fitting portion are not deteriorated. Absent.

In the first and second embodiments, in order to use the T-shaped drawing tool (6) as shown in the figure, the upper side of the stepped hole (5) is formed into the long hole (5a). Also, the lower side was formed into a circular hole (5b), but when using a drawing tool equipped with an L-shaped hook-shaped hooking piece, for example, instead of the long hole (5a), a circular hole or a small hole is used. It may be an elliptical hole or the like. The point is that the stepped hole (5) may have a hole shape in which a step portion capable of locking the hook-shaped hooking piece is formed.

[0023]

[Effect of the device]

 According to the present invention, the following effects can be obtained. (a) Since the shim can be reliably pulled out from the recess simply by inserting the extraction tool into the stepped hole formed in the shim and pulling it up, compared to the conventional one with a through hole. , The replacement work of the shim becomes quick.

(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 vertical sectional front view showing a first embodiment of the present invention.

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

FIG. 3 is a vertical cross-sectional front view of essential parts showing a second embodiment of the present invention.

FIG. 4 is a central vertical sectional front view schematically showing a direct acting valve 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) Stepped hole (5a) Long hole (5b) Circular hole (6) Extraction tool (6a) Hooking piece

Claims (1)

[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 tappet formed by fitting, a stepped hole having an opening area on the lower side larger than that on the upper side is bored in an appropriate position of the shim in the plate thickness direction.