JPH07651Y2 - Hydraulic valve lash adjuster - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a hydraulic valve lash adjuster used in an internal combustion engine.

[Conventional technology]

In the conventional hydraulic lash adjuster, the plunger comes into contact with the rocker arm via the spherical sliding surface, and in order to lubricate the sliding surface, the sliding surface and the reservoir chamber inside the plunger are connected. The plunger may be provided with a lubricating hole for communication. In this case, when the engine is operated, an appropriate hydraulic pressure is applied to the reservoir chamber, and the oil slightly flows out from the lubricating hole. The oil flowing into the reservoir chamber contains a small amount of air bubbles, which rise due to buoyancy,
The oil flows out to the outside from the lubrication port to the extent that it does not accumulate in the reservoir chamber.

However, since the space between the concave sphere of the rocker arm and the convex sphere of the plunger is very small, if a large amount of these bubbles are contained in the engine oil and they flow into the reservoir chamber, However, since it takes time to discharge the air from the lubrication hole, there is a problem that air flows into the high pressure chamber before the air is discharged and a tapping sound is generated from the valve operating system.
In addition, in order to increase the outflow amount of oil from the lubrication hole, there is an example in which an open hole that communicates with the lubrication hole and is open to the atmosphere is provided in the concave spherical portion of the rocker arm. It is difficult, and when the engine is stopped, a temporary negative pressure is generated in the cylinder head oil gallery, air enters through the lubrication holes, and the oil in the reservoir chamber is drawn out to the cylinder head oil gallery for the next start. There was a problem that the oil required for the above was not retained in the reservoir chamber.

[Means for solving problems]

The present invention is intended to solve such a problem, and a plug having a large-diameter cylindrical portion at the upper end, a small-diameter cylindrical portion at the middle, and a threaded portion at the lower end is provided on the plunger head and has a large inner diameter at the upper portion. It is characterized in that it is assembled so that the threaded portion of the plug protrudes into a bearing portion in which a portion is formed and a female threaded portion is formed in the lower portion.

〔Example〕

An embodiment of the present invention will be described with reference to FIG. Plunger 12
Is slidably fitted in a bottomed cylindrical body 11 fitted in the cylinder head 1, and the concave spherical portion of the rocker arm 7 slidably contacts the convex spherical head of the plunger. A high-pressure chamber 19 is formed between the plunger and the body, a reservoir chamber 18 is formed inside the plunger, a return spring 13 is provided inside the high-pressure chamber 19 between the body and the plunger, and a check is made at the bottom of the plunger. A valve 14 is provided. The oil gallery 9 of the cylinder head 1 communicates with the reservoir chamber 18 via the first oil supply hole 15 provided in the body and the second oil supply hole 16 provided in the plunger.

A plug bearing 40 is provided on the convex spherical head of the plunger, and the plug 30 is attached thereto.

The plug 30 has a large-diameter cylindrical portion 31 at its upper portion, a small-diameter cylindrical portion 33 having an outer diameter smaller than that of the large-diameter cylindrical portion at its middle portion, and an outer diameter at its lower portion than the small-diameter cylindrical portion. Has a threaded portion 34 which is also larger and smaller than the large diameter cylindrical portion.

The plug bearing portion has a large inner diameter portion 41 having an inner diameter slightly larger than the outer diameter of the large diameter cylindrical portion 31 at its upper portion, and a female thread portion 43 corresponding to the screw portion 34 at its lower portion, and its inner diameter. Is larger than the outer diameter of the small diameter cylindrical portion.

The plug 30 is assembled by being screwed into the support portion 40 until the screw portion 34 projects into the reservoir chamber 18.

Since the axial length of the small-diameter cylindrical portion 33 is set longer than that of the female screw portion 43, the plug 30 can move in the axial direction accordingly.

The hydraulic valve lash adjuster is
The hydraulic oil is sent from the oil gallery 9 of the cylinder head at an appropriate pressure, and the hydraulic oil is supplied to the first oil supply hole 15 and the second oil supply hole 16
To reach the reservoir chamber 18. A part of the hydraulic oil that has reached the reservoir chamber is guided to the high pressure chamber, and the other goes upward. The hydraulic pressure in the reservoir chamber pushes the plug 30 out,
Moves until it contacts the upper wall 44 of the reservoir or the head 37 contacts the rocker arm ball 21. The oil in the reservoir chamber has a large gap between the small diameter cylindrical portion 33 and the female screw portion 43, and the large diameter cylindrical portion.
It flows out of the plunger through the gap between 31 and the large inner diameter portion 41. The amount of hydraulic oil outflow is limited by the size of this gap. A part of the hydraulic oil that has flown out lubricates the spherical surface 21, and the other is discharged to the outside from the rocker arm hole 10. Air in the oil is also discharged as the hydraulic oil flows out.

Cylinder head oil gallery 9 when the engine stops
When a temporary negative pressure is generated in the gallery 9 due to the difference between the oil pan and the oil pan, the negative pressure is also transmitted to the reservoir chamber to pull in the plug 30. Since the joint surface 32 of the plug and the seat surface 42 are in liquid-tight contact with each other, it is possible to prevent air from entering the reservoir chamber, so that the oil in the reservoir chamber is retained and ready for the next engine start.

The embodiment of the plug according to the first embodiment of the present invention has been described in detail above. The plugs according to the second embodiment, the third embodiment and the fourth embodiment of the present invention which are modifications of this embodiment are described above. The configuration will be briefly described below.

According to the second embodiment of the present invention, as can be seen clearly from FIG. 5, the plug 30 has a cylindrical portion cap having an outer diameter larger than the large diameter cylindrical portion 31 'above the large diameter cylindrical portion 31'. 36 is formed, and the plug bearing portion 40 is formed with a cap receiving portion 46 having an inner diameter slightly larger than the outer diameter of the cylindrical cap portion above the large inner diameter portion 40 '. The axial length of the large diameter cylindrical portion 31 'of the plug is the same as the large inner diameter portion 41' of the plug support portion.
Is formed to have a shorter axial length. A joint surface 32 'extending radially between the cap portion and the large diameter cylindrical portion.
And the seat surface 42 'extending in the radial direction between the cap receiving portion and the large inner diameter portion are substantially liquid-tight when they abut each other.

According to the third embodiment of the present invention, as can be seen from FIGS. 6 and 7, the flow rate adjusting plug has a large diameter cylindrical portion 31 formed at an upper portion thereof and a small diameter cylindrical portion 33 formed at a lower portion thereof. Is
At least one protrusion 34b is provided on the small diameter cylindrical portion.

According to the fourth embodiment of the present invention, as can be seen from FIG. 8, the flow control plug has a large diameter cylindrical portion formed in an upper portion thereof and one or a plurality of legs 33-C extending in an axial direction in a lower portion thereof.
And the legs are provided with radially extending projections 34-C.

[Effect of device]

Since the flow rate adjustment plug is inserted using the screw mechanism without giving any deformation, the accuracy of the gap that adjusts the outflow amount and the seat part that keeps the liquid tightness are accurately maintained even after the plug is assembled. .

Even when there is a concern that air may enter the high-pressure chamber 19 until the hydraulic valve lash adjuster is installed in the engine, screw holes 43 should be inserted after inserting the hydraulic valve lash adjuster into the cylinder head and before installing the rocker arm. It was possible to easily extract the air from the high-pressure chamber by inserting the rod reaching the check valve 14 and pushing down the plunger 12 while pressing the check valve, and then to assemble the plug 30. Even when it is necessary to discharge air from the high-pressure chamber 19 during engine maintenance, remove the rocker arm and apply hydraulic pressure from the oil gallery 9,
By rotating the plug 30, the plug 30 can be removed, and air can be extracted by the same procedure as described above.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a conventional example in which the oil in the reservoir has escaped due to the negative pressure of the gallery 9 after the engine has stopped, and FIG. 2 shows the oil in the reservoir after the engine has stopped. FIG. 3 is a cross-sectional view of the first embodiment of the present invention held, ie the plug closed, and FIG. 3 shows the oil flow during engine operation (the plug is open). FIG. 4 is a sectional view of the first embodiment, FIG. 4 is an enlarged view showing a plunger head of a first embodiment of the present invention, and FIG. 5 is a plunger head of a second embodiment of the present invention. FIG. 6 is an enlarged view showing a plunger head of a third embodiment of the present invention, FIG. 7 is a perspective view of a plug of the third embodiment, and FIG. FIG. 8 is a perspective view of the plug of the fourth embodiment. 1 ... Cylinder head, 11 ... Cylindrical body with bottom 12 ... Plunger, 18 ... Reservoir chamber 19 ... High pressure chamber, 30 ... Plug 40 ... Plug support

Claims (5)

[Scope of utility model registration request] 1. A hollow cylindrical plunger is slidably fitted in a bottomed cylindrical body, a high pressure chamber is formed between the body bottom portion and the plunger bottom portion, and a reservoir chamber is formed in the plunger. A check valve that allows only the flow from the reservoir chamber to the high-pressure chamber is provided at the bottom of the plunger, and a small-diameter opening is provided at the end of the plunger opposite to the check valve. In a hydraulic valve lash adjuster that communicates with the outside through a first oil supply port penetrating the body peripheral wall and a second oil supply port penetrating the plunger peripheral wall, a large diameter cylindrical portion is at the upper end, a small diameter cylindrical portion is at the middle, and a screw is at the lower end A flow control plug having a threaded portion, the outer diameter of the threaded portion being smaller than the large-diameter cylindrical portion and larger than the small-diameter cylindrical portion, is slightly larger than the large-diameter cylindrical portion of the plug. A plug bearing provided on the upper part of the plunger, which comprises a large inner diameter part having a diameter and an axial length which is shorter than the small diameter part of the plug and is provided with an internal thread corresponding to the plug thread part. A hydraulic valve lash adjuster, characterized in that the plug screw portion is assembled to the portion with the female thread portion of the support portion passing through. 2. A joint surface extending in the radial direction between the large diameter cylindrical portion and the small diameter cylindrical portion of the plug, and a seat surface extending in the radial direction between the large inner diameter portion of the plug support portion and the female screw portion. Characterized in that when they come into contact with each other, they become substantially liquid-tight,
The hydraulic valve lash adjuster according to claim 1. 3. A cylindrical cap portion having an outer diameter larger than that of the large-diameter cylindrical portion is formed on an upper portion of the large-diameter cylindrical portion of the plug, and an inner diameter is provided on an upper portion of the large-inner-diameter portion of the plug bearing portion. A cap receiving portion that is slightly larger than the outer diameter of the cylindrical cap portion is formed, and the axial length of the large diameter cylindrical portion of the plug is shorter than the axial length of the large inner diameter portion of the plug support portion. However, substantially when a joint surface extending in the radial direction between the cap portion and the large-diameter cylindrical portion and a seat surface extending in the radial direction between the cap receiving portion and the large inner diameter portion are in contact with each other. The hydraulic valve lash adjuster according to claim 1, wherein the hydraulic valve lash adjuster is liquid-tight. 4. A large-diameter cylindrical portion is formed on an upper portion and a small-diameter cylindrical portion is formed on a lower portion, and the small-diameter cylindrical portion has a flow rate adjusting plug having at least one protrusion. The hydraulic valve lash adjuster described in 1). 5. A large-diameter cylindrical portion is formed in an upper portion, and one or a plurality of legs 33-C extending in the axial direction is provided in the lower portion, and the leg is provided with a protrusion 34-C extending in the radial direction. The hydraulic valve lash adjuster according to claim 1, further comprising a flow rate adjusting plug.