JPS5833201Y2 - Ninenki Kanyou Benkikou - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a valve mechanism for an internal combustion engine that can prevent noise due to tappet rattling (axial movement) during a valve closing period.

The noise of an internal combustion engine valve mechanism that has a tappet between the valve and the cam comes from (1) the seating sound when the valve seats on the valve seat, and (2) the noise between the tappet and the valve when the tappet starts to be pushed up by the cam. Contact noise, noise caused by (3) rattling axial movement of the tappet during the pulp closing period) can be roughly classified into 03 types.

Most of the above (1) and (2) have now been solved by improving the cam profile.

That is, by improving the cam profile, the tappet is gently pushed up to bring it into contact with the valve, or the lift is gently reduced so that the valve gently seats against the valve seat.

However, since no countermeasures have been taken for the above (3) at present, as countermeasures for (1) and (2) progress, the proportion of noise caused by (3) increases, and the situation cannot be ignored in terms of noise countermeasures.

In order to eliminate the noise mentioned in (3) above, the present invention provides a chamfered portion on the periphery of both end surfaces of the valve and tappet that contact each other.
It is characterized in that an elastic ring is tightly fitted between the double-sided chamfered portions so that the pulp and tappet move together during operation, and will be explained in conjunction with the drawings as follows.

FIG. 1 is a vertical cross-sectional partial view showing an example of a conventional valve mechanism.
is a cylinder, 2 and 3 are a valve seat and a pulp guide fixed to the cylinder 1, 4 is an intake or exhaust valve, 5 is an intake or exhaust port that is opened and closed by the valve 4, 6 is a cylinder head, 7 is a stop fitted into the annular groove provided at the lower end of the valve 4; 8 is a retainer that is prevented from being removed by the I/i stop 7; 9 is a valve spring; 10 is a tappet; 11 is a bearing of the crankcase 12. This is the cam profile provided on the 13U camshaft 11 (cam shirt supported by the camshaft 11).

In addition, in consideration of thermal expansion of the valve 4, tappet 10, etc., a tappet gap 14 is provided between them, and in this way, the tappet 10 tends to vibrate in the axial direction within the range of the tappet gap 14 during the conventional hahalb closing period. , the structure is such that the problem (3) above cannot be avoided.

In this invention, during the pulp closing period, valve 4 and tappet 1
Chamfered portions 18 and 19 are provided around the mutually contacting end surfaces 16 and 17 of the valve 4 and the tappet 10, and an elastic ring 20 is tightly fitted between the double-sided chamfered portions 18 and 19 so that the valve 4 and the tappet 10 move together. There is.

The ring 20 can be made of, for example, heat-resistant rubber, Teflon, etc. and has a circular cross section, and has chamfered portions 18,
The diameter and cross section in the free state are pressed so as to fit into the V-shaped groove in cross section formed by the double-sided chamfered portions 18 and 19, and to seal the space 21 between both end surfaces 16 and 17. Size etc. are set.

Chamfers 1B, 19Fi may be conventionally shown in FIG. 2, or a convex curved chamfer may be used to increase the durability of the ring 30.

The cross-sectional shape of the ring 20 does not necessarily have to be an exact circle, and may have an outwardly opening V-shaped cross-sectional shape so that it can be wedged into the chamfered portions 18 and 19 by a wedge action, but from the viewpoint of ease of manufacture and availability. It is convenient to use an O-ring with a circular cross section.

When the engine is operated, the air in the space 21 (Fig. 3) between the valve 4 and the tappet 10 is forcibly compressed during the valve thrusting operation, pushes the ring 20 up from the chamfered portions 1B and 19, and escapes to the outside. Surface 16, 17/li
Close contact (Figure 4).

During the pulp closing period, there is a negative pressure in the space 21 between the end faces 16 and 17, but since the ring 20 is attached, the end faces 16 and
Air cannot enter between 17, so both end faces 16
．． llj Maintain close contact or almost close contact as shown in Figure 4.

Therefore, even during the valve closing period, the tappet 10 is secured by the valve 4, does not rattle, and does not generate noise.

When assembling the valve mechanism according to the present invention, since the ring 20 is simply interposed between the valve 4 and the tappet 10, the assembling performance is hardly changed and assembly is easy.

Also, the valve operating function is not affected at all. When inspecting the tappet gap 14, for example, by pushing the ring 20 up toward the valve 4 side or pushing it down toward the tappet 10 side, the tappet gap can be easily inspected as before.

Furthermore, by smoothing the chamfers of the chamfered portions 18 and 19, the durability of the ring 20 can be further increased.

As explained above, according to the present invention, the following effects can be obtained.

(a) During engine operation, both end surfaces 16 and 17 remain in substantially close contact with each other, so rattling and noise of the tappet 10 during the pulp closing period can be reliably prevented.

(b) Since only the ring 20 is interposed between the valve 4 and the tappet 10, assembly is extremely easy, and the valve operating function is not affected at all.

(c) The structure is extremely simple, and only one of the conventional chamfered portions of the valve 4 and tappet 10 can be used;
The cost will not be high.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional partial view showing an example of a conventional valve mechanism;
The figures are a partial enlarged view of FIG. 1, FIG. 3d is a partial side view of the valve mechanism to which the present invention is applied when it is at rest, and FIG. 4 is a side view of the valve mechanism when it is in operation. 4 is the valve, 10 is the tappet, 1 is the cam, yv
Soft 13 is the cam profile, 16 and 17 are the end faces, 18
゜19 is a chamfered portion, and 20 is a ring (elastic ring).

Claims (1)

[Scope of utility model registration request] In a valve mechanism for an internal combustion engine that has a tappet between the valve and the cam, a chamfer is provided on the periphery of both end surfaces where the valve and the tappet come into contact with each other, and an annular ■groove shape is formed on both sides of the chamfer. A valve mechanism for an internal combustion engine, characterized in that a seal ring made of an elastic body is tightly fitted between the double-sided chamfered portions to seal the two end faces so that the two end faces are always kept in close contact or substantially close contact.