JPS59162311A - Sealed type oil-hydraulic lifter - Google Patents

Abstract

PURPOSE:To secure sufficient amount for adjustment of clearance as well as make the arrngement in small size by furnishing a plunger in a small dia. bore, and installing a diaphragm for absorption of volume change in a large dia. bore. CONSTITUTION:A small dia. bore 24 and a large dia. bore 25 are formed in the body 26 of a sealed type oil-hydraulic lifter 20, and a plunger 27 is inserted in the small bore 24 slidably through seal 28 so as to form a pressure chamber 30. The periphery of a diaphragm 31 having a larger dia. than the plunger 27 is fixed to the large bore 24 so as to form a reserver chamber 34. This reserver chamber 34 is in communication with said pressure chamber 30 through leak clearance 40 and passage 41. Because of large dia. of this reserver chamber 34, absorption of volume change is possible even though a sufficiently large amount is provided for adjustment of clearance, and also the overall length of the lifter can be suppressed small.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic lifter used in a valve mechanism of an internal combustion engine, and in particular, the hydraulic lifter has a built-in fluid and requires an external supply of fluid during pulp operation. The present invention relates to an improvement of a sealed hydraulic lifter that does not have a hydraulic lift.

Conventionally, the above-mentioned type of sealed hydraulic lifter was manufactured using
The device described in Japanese Patent No. 43125 is already known. This conventional hydraulic lifter is explained with reference to Fig. 1. This hydraulic lifter is designed to keep the pulp clearance at zero during the operation of the internal combustion engine's valve mechanism, prevent noise generation, and ensure reliable valve operation. It has a body 10 whose lower end contacts the cam surface of the camshaft, and a cam 12 disposed within the body 10 to reciprocate with the plunger 11 and operatively interlock with the rocker arm. 1. If a clearance is created in the valve mechanism due to thermal expansion of the cylinder block or cylinder head of an internal combustion engine, or if the dimensions become longer, the plunger 11 should be It moves up and down relatively.1 For this purpose, there is a pressure chamber 13 inside the body and a diaphragm 14 inside the plunger 11.
a reservoir chamber 15 formed by the reservoir chamber 15;
It has a check valve 16 that allows pressure oil to flow only from the pressure chamber 18 to the pressure chamber 18, and a leak clearance 17i that returns oil from the pressure chamber 18 to the reservoir chamber 15. This diaphragm 14 is deformable and absorbs the volume change of the reservoir hole 15 due to the relative operation of the plunger 11, and the amount of deformation is determined by the outer diameter and stroke of the plunger 11. The stroke of the plunger 11 needs to be more than a predetermined amount because it is the amount required to maintain the clearance of the valve mechanism at zero, but if the diameter of the plunger 11 is made smaller, the diameter of the diaphragm disposed inside the plunger 11 will be reduced. It has the disadvantage that it becomes too small and cannot absorb the above-mentioned volume change. Therefore, it is necessary to make the outer diameter of the plunger relatively large, and there is a drawback that it is difficult to downsize the hydraulic lifter itself.

An object of the present invention is to enable miniaturization of a hydraulic lifter.

The configuration of the present invention includes: a plunger disposed to reciprocate within the small diameter bore of a body having a small diameter bore and a large diameter bore; a pressure chamber formed by the plunger and the body; is fixed and has a reservoir chamber formed in the body by a diaphragm having a larger diameter than the plunger.Since the diaphragm is disposed outside the plunger, the diameter of the plunger can be made as small as possible. Therefore, the diameter of the diaphragm that absorbs the volume change determined by the diameter and stroke of the plunger can be made correspondingly smaller, achieving the intended purpose of downsizing the h11 pressure lifter itself.

The present invention is as described above, and since the diaphragm has a large diameter compared to the outer diameter of the 1 flange, the deformation of the diaphragm to absorb volume changes is small, and the durability of the diaphragm is improved. be. In addition, in the conventional device shown in Fig. 1, a diaphragm is disposed within the plunger, so the smaller the plunger is, the more the diaphragm is deformed to the extent that it comes into contact with the inner diameter of the plunger, and the cold and heat resistance is generally better. Although the diaphragm made of rubber or the like has the disadvantage of being easily worn out, the present invention, in which the diaphragm is disposed outside the plunger, has the advantage of not having this disadvantage.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 2 shows the first embodiment of the present invention, and shows an OHC direct type sealed hydraulic lifter 20, which connects the cylinder head boat of the internal combustion engine and the combustion chamber. Valve stem 2■ of the valve that controls the
It is arranged between the cam surfaces 28 of the camshaft 22.

The lifter 20 has a small diameter bore 24 and a large diameter bore 25'jf:
In the small diameter bore 24, a plunger 27 that abuts the upper end of the valve stem 21 is disposed so as to be able to reciprocate through an X-shaped seal 28. The body 26 has a wall 29 slightly above the center thereof, whereby a pressure chamber 80 is formed therein together with the first lange 27. The outer periphery of a diaphragm 81 is press-fitted into the large diameter bore 25 of the body 26 , and the diaphragm 81 is fixed to the cover 3 which is fixed to the body 26 and contacts the cam surface 28 .
2 and the protrusion 83 of the body 26.

The outer circumference of this diaphragm 81 is the diaphragm 3.
1 and the body 26; It has a protrusion 46 that has a sealing function to prevent leakage of pressure fluid from the inside. As described above, the plunger 27 is disposed within the small diameter bore 24 of the body 26, and the diaphragm 8] is disposed in the large diameter bore 25 of the body 26, so the diaphragm 81 has a larger diameter than the plunger 27.
In order to allow pressure fluid, for example silicone oil, to flow only to the pressure chamber 80 side between the reservoir blockages 84 formed by
A check valve 85 is disposed between the compartments, and the check valve 85 is constantly biased in the direction of closing the passage 88 formed in the wall portion 29 by a spring 37 whose one end is engaged with a retainer 86. This retainer 36 is always urged to the illustrated position by a spring 89 attached to the plunger 27.

When the plunger 27 operates in the direction of compressing the pressure chamber 80, the pressure fluid in the pressure chamber 30 flows through the leak clearance 401 formed between the body 26 and the plunger 27.
Passages 41, 42, 43' formed in the body 26? f:
It returns to the reservoir chamber 84 via the air. The amount of pressure 616 returned to the reservoir chamber 84 corresponds to the stroke and diameter of the plunger 27.
Accordingly, the volume of the reservoir chamber 341 can be changed by deforming the diaphragm 81, which is configured as the atmospheric chamber 5 in its upper part.

In the above configuration, the camshaft 22 rotates as the inner deflector rotates, and during its lift stroke, when the cover 28 and the body 26 are pushed down in the downward direction in the figure, the oil pressure in the pressure chamber 80 increases, and the check valve 85 closes. At this time, oil leaks from inside the pressure chamber 80.
, returns to the reservoir chamber 84 via the passage 41°42.43'iz. Therefore, the plunger 27 is inserted into the body 2 by a predetermined dimension.
It will sink against 6. Next, the camshaft 22 rotates further, and when the camshaft stroke is completed and returns to the base circle, the body 26 is lifted by the force of the spring 89, so that the entire length of the lifter is extended by a predetermined amount.

As a result, the oil pressure in the pressure chamber 80 decreases, the check valve 35 opens, the oil in the reservoir chamber 34 flows into the pressure chamber 30, and the hydraulic lifter as a whole returns to its original length. In this way, the hydraulic lifter 20 repeatedly expands and contracts by the above-described predetermined dimension during operation to maintain the pulp clearance of the valve mechanism at zero. sealed hydraulic lifter 51i
2, parts that are substantially similar to those in FIG. 2 are designated by the same numbers, and detailed explanations are omitted.

In this modification, the body 5 is attached to the rocker arm 50.
2, a small diameter bore 58 and a large diameter bore 54 similar to those in the above-mentioned example 1.1 h are formed, a plunger 27 is arranged in the small diameter bore 53 so as to be able to reciprocate, and the outer circumference of the diaphragm 81 is disposed in the large diameter bore 54. part is press-fitted. This diaphragm 3
1 has a protrusion 55 of a body 52 and an atmospheric passage 56, and is fixed by a cover 57 fixed to the body 52. Therefore, compared to the plunger 27 as in the previous embodiment.

The diaphragm 31 is formed with a large diameter t;1. Furthermore, X
A shaped seal 58 is disposed within a recess formed in plunger 27 .

In the modified example borrowed as described above, the heuchi ta
As the body 52 of the rocker arm 50 rotates, the body 52 of the rocker arm 59 swings in the vertical direction as shown in the figure.

It is clear that the sealed hydraulic lifter of the present invention can be applied to systems other than the OHC type.

[Brief explanation of drawings]

Figure 1 is a sectional view showing a conventional sealed hydraulic lifter, Figure 2 is a sectional view showing a conventional sealed hydraulic lifter;
The figure is a sectional view of a sealed hydraulic lifter showing an actual example of the present invention, and FIG. 3 is a modified example of the present invention. FIG. 20.51... Sealed hydraulic lifter, 24.53...
Small diameter bore, 25.54...Large diameter bore, 26.52...
・Body, 27...Plunger, 80...Pressure chamber,
81...Diaphragm, 34...Reservoir 6.35
...Check valve, 89...Spring, 40.
...Leak clearance! 1! ? One person: Noriyoshi Aisin Seiki Co., Ltd. Representative: Reio Nakai Figure 1 Figure 2 Shi1 Ri 9

Claims (1)

[Claims] A body having a small diameter bore and a large diameter bore, a plunger arranged to reciprocate within the small diameter bore of the body via a seal, a pressure chamber formed by the plunger and the body, and a large diameter bore of the body. A diaphragm having a fixed outer periphery and having a larger diameter than the plunger, a reservoir chamber formed in the body by the diaphragm, a check valve that allows pressure fluid to flow only from the reservoir chamber side to the pressure chamber, and the plunger. A leak clearance formed between the bodies, a passage formed in the body to communicate with the diagnostic leak clearance and return pressure fluid from the pressure chamber to the reservoir chamber, and a return spring that biases the plunger in one direction. Sealed hydraulic lifter.