JPH0447366Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a hydraulic valve lash adjuster that is fitted into a cylinder formed in a cylinder head or rocker arm.

[Conventional technology]

In recent years, hydraulic valve lash adjusters have been widely used in engine valve systems to automatically adjust valve lashes (valve clearances). Such adjusters are generally fitted in an upright or vertical position within a cylinder formed in a cylinder head or rocker arm, and are adapted to receive hydraulic fluid from an oil supply circuit provided in the cylinder head or rocker arm. .

On the other hand, with the development of various types of engines, hydraulic valve lash adjusters have come to be installed in various positions depending on the direction or position of the engine.

Figure 1 shows a DOHC typical horizontally opposed engine.
FIG. 2 is a layout diagram of a type valve train. In the figure, 1 is a hydraulic valve lash adjuster fitted into the cylinder of the cylinder head, 2 is a rocker arm on which the valve lash adjuster acts on one end, 3 is a cam for swinging the rocker arm, and 4 is a rocker arm. This is the valve stem that abuts the other end. Figure 2 is a layout diagram of the OHC valve system of a typical horizontal engine. In the figure, reference numeral 1' denotes a hydraulic valve lash adjuster that is incorporated in a rocker arm 2 that swings under the action of a cam 3 and that acts on a valve stem.

When conventional hydraulic valve lash adjusters are used for the lower and upper parts of the valve train as shown in Figs. , a cylindrical outer plunger or a cylindrical body that is fitted with a small gap communicating with the outside, and a cylindrical outer plunger or a cylindrical body that is fitted into the inside of the cylindrical outer plunger with a small gap so as to be slidable in the axial direction, and a bottom part The high pressure chamber is composed of a cylindrical inner plunger having an orifice, and a plunger head having an open end having a notch in contact with the open end of the inner plunger and a closed end in contact with a rocker arm or a valve stem. It is located vertically above the reservoir chamber as a whole. A check valve is provided in the orifice at the bottom of the inner plunger. Hydraulic oil from an oil supply circuit provided in the cylinder head or rocker arm flows into the reservoir chamber through a notch in the plunger head.

[Problem that the invention attempts to solve]

Hydraulic oil flowing into the reservoir chamber from the oil supply circuit through the oil filler port usually has many air bubbles. When the hydraulic valve latch adjuster is in an upright position, the air bubbles in the hydraulic oil that have flowed into the reservoir chamber move upwards in the reservoir chamber (upward in an upright position) due to buoyancy, and above the plunger head (in an upright position). The oil exits the valve brush adjuster through an opening (or oil drain port) provided in the upper part of the valve through a gap between the outer circumferential surface of the plunger head and the inner circumferential surface of the cylindrical outer plunger. However, in the inclined position shown in Figs. 1 and 2,
Air bubbles that enter the reservoir chamber through the notch in the plunger head enter the reservoir chamber portion of the inner plunger due to their buoyancy, and then enter the high pressure chamber when the check valve is opened during operation of the valve brush adjuster. It turns out. I mean,
This is because the conventional hydraulic valve lash adjuster does not have a means for actively removing air bubbles between the high pressure chamber and the fuel filler port. The air bubbles that have entered the high pressure chamber enter the high pressure chamber again through the notch in the plunger head as the hydraulic oil flows through the gap between the inner peripheral surface of the outer plunger and the outer peripheral surface of the inner plunger. Due to the recirculation of air bubbles, the air concentration in the upper part of the reservoir chamber and in the high pressure chamber gradually increases, and when it reaches a certain predetermined level, the rigidity of the valve brush adjuster decreases, producing a hammering sound from the valve train, and the valve. This may cause the lash adjuster to malfunction.

The purpose of the present invention was to solve the above-mentioned problems, and to provide a hydraulic valve lash adjuster that prevents air bubbles from entering the high pressure chamber located above the reservoir chamber as a whole. be.

[Means for solving problems]

In order to achieve the above object, according to the present invention,
A cylindrical outer plunger is fitted in a cylinder communicating with the engine oil supply circuit in an inclined position with a gap communicating with the outside, and a cylindrical inner plunger with an orifice at the bottom is disposed inside the outer plunger. The plunger head is slidably inserted into the outer plunger, and a plunger head is placed within the outer plunger.
An open end of the plunger head having a notch abuts the open end of the inner plunger opposite to the orifice, and a reservoir chamber formed in the inner plunger and the plunger head is provided at the bottom of the inner plunger. In a hydraulic valve lever adjuster in which a check valve is arranged to allow hydraulic oil to flow only in the direction of the high pressure chamber formed by the bottom and the outer plunger, the outer plunger is provided with a check valve opposite to the high pressure chamber. An oil inlet communicating with the engine oil supply circuit is provided near the open end on the side, an oil inlet to the reservoir chamber is formed in the plunger head in alignment with this, and an oil inlet is provided between the high pressure chamber and the oil inlet. A bubble discharge communication port is provided in the upper wall of the outer plunger in alignment with the notch of the plunger head, and the bubble discharge communication port is connected to an annular bubble formed on the outer peripheral surface of the outer plunger and communicating with the gap. To provide a hydraulic valve lash adjuster, which is opened to a collection chamber and has an orifice of an inner plunger from a reservoir chamber to a high pressure chamber projected into the reservoir chamber by a predetermined distance in a tubular shape.

〔Example〕

The hydraulic valve lash adjuster of the present invention will be explained with reference to FIG. FIG. 3 shows the configuration of a hydraulic valve lash adjuster on the lower side of the DOHC valve train of the typical horizontally opposed engine shown in FIG.

As shown in FIG. 3, the hydraulic valve latch adjuster 1 is a cylindrical cylinder that is fitted into an inclined cylinder formed in a cylinder head 26 with a small gap 20 between it and the inner peripheral surface of the cylinder. It has a shaped outer plunger or cylindrical body 5. The gap 20 communicates with the outside of the hydraulic valve latch adjuster or the surrounding environment via an oil hole 21 in the cylinder head 26. A cylindrical inner plunger 7 is fitted into the cylindrical outer plunger 5 so as to be slidable in the axial direction with a gap 25 between it and the sliding surface of the outer plunger. At the diagonally lower end of the inner plunger 7, as seen in FIG. 3, rests the open end of a plunger head having a cutout or opening 16. The opposite end of the plunger head abuts one end of the rocker arm. A seat or bottom portion 32 for the check valve 8 is fixed to the diagonally upper end of the inner plunger 7 by brazing, caulking, welding, or the like. Inner plunger 7
The bottom portion 32 of has an integral tubular orifice 31 extending approximately through its center;
protrudes a predetermined distance into the reservoir chamber 23, which is composed of an inner plunger and a plunger head. A bubble reservoir 22 is formed between the outer surface of the upper wall of the tubular orifice 31 and the inner surface of the upper wall of the inner plunger 7 immediately above it. A high pressure chamber 24 is formed between the bottom of the outer plunger and the bottom 32 of the inner plunger. At the bottom of the cylindrical inner plunger 7, oil flows only in the direction from the reservoir chamber 23 formed in the plunger head 6 and the inner plunger 7 to the high pressure chamber 24 formed by the bottom of the inner plunger 7 and the outer plunger 5. A check valve 8 is arranged to allow the flow of water. As illustrated, the high pressure chamber 24 is located above the reservoir chamber 23 as a whole. Reference numeral 10 designates a return spring that contacts the bottom of the plunger 7 and the closed end of the main body 5 via the retainer 9, and 11 represents a check valve spring held by the retainer 9.

In the hydraulic valve latch adjuster of the present invention, the cylindrical outer plunger 5 extends over its peripheral wall near its open end opposite the high pressure chamber 24, and is connected to an oil supply circuit 1 provided in the cylinder head.
It has an annular oil introduction chamber 13 communicating with 2, and has an oil introduction port 14 at a predetermined location on the peripheral wall. In this embodiment, the oil inlet 14 is formed on the lower wall of the outer plunger 5, but it may be provided on the upper wall. On the other hand, the plunger head 6 has a communication groove 17b and an oil supply port 15 corresponding to the oil inlet 14 of the outer plunger 5. It can be seen that in the present invention, the distance between the high pressure chamber 24 and the fuel filler port 15 is quite long. Further, the outer plunger 5 has a bubble discharge communication port 18 on the upper wall portion approximately in the middle of its length, correspondingly aligned with the notch 16 at the open end of the plunger head 6 and the communication groove 17a. The outer plunger 5 also has an annular air bubble collection chamber 19 on its outer peripheral surface corresponding to the air bubble discharge communication port 18. Outer plunger 5
The air bubble collection chamber 19 communicates with a gap 20 between the inner circumferential surface of the cylinder and the outer circumferential surface of the outer plunger 5 and thus communicates with the outside of the hydraulic valve lash adjuster 1 .

During operation, hydraulic oil containing a large amount of air bubbles is
The oil flows from the oil supply circuit 12 of the cylinder head through the oil introduction chamber 13 and oil introduction port 14 of the outer plunger 5, and then through the communication groove 17b of the plunger head 6 and the oil supply port 15 into the reservoir chamber 23. Bubbles move vertically due to their buoyancy. As mentioned above, since the distance between the high pressure chamber 24 and the oil filler port 15 is quite long, the air bubbles, together with the hydraulic oil,
Notch 16 and communication groove 1 in the plunger head without entering the reservoir chamber part of the inner plunger.
7a and through the air bubble discharge opening 18 of the outer plunger, it enters the air bubble collection chamber 19 and collects there. Thereafter, the bubbles pass through the gap 20 together with a small amount of hydraulic oil and are discharged to the outside of the hydraulic valve lash adjuster via the oil hole 21. If air bubbles are released from the notch 16 through the air bubble discharge communication port 1,
Even if the bubbles do not escape to the high pressure chamber 8 and pass in front of it, the bubbles will remain in the bubble reservoir 22, and the tendency of the bubbles to flow into the high pressure chamber is extremely reduced. In case,
Even if air bubbles enter the high-pressure chamber 24, the air bubbles, together with a small amount of hydraulic oil, due to the high pressure of the hydraulic oil in the high-pressure chamber 24, will close to the gap 25 between the inner circumferential surface of the outer plunger and the outer circumferential surface of the inner plunger. It reaches the communication groove 17a through the passageway, and then follows the above-mentioned route to exit the hydraulic valve rush adjuster.

Figure 4 shows a diagram for the transverse engine shown in Figure 2.
A cross-sectional view of a so-called Rocker arm internal type hydraulic valve lash adjuster as another embodiment of the present invention on the upper side of an OHC valve train. The concept of the present invention can also be applied to such a hydraulic valve lash adjuster built into a rocker arm in the same manner as the embodiment shown in FIG. The difference from the one in FIG. 1 is that a cylindrical outer plunger 5 having a flange 5b that is attached to the rocker arm 2 in a liquid-tight manner is provided in the rocker arm 2, and an annular air bubble collection chamber 19 of the outer plunger 5 is provided in the gap 2.
0, the closed end of the plunger head 6 acts directly on the valve stem 4, and an oil supply circuit 1 in the rocker arm 2
2, and the oil inlet 14 of the outer plunger 5 is provided in the lower wall of the outer plunger. However, the essential functions and effects of the hydraulic valve lash adjuster remain the same.

[Effect of idea]

According to the present invention, in a hydraulic valve latch adjuster fitted in a cylinder of a cylinder head or a rocker arm in an inclined position, an oil inlet of a cylindrical outer plunger communicating with an oil supply circuit in the cylinder head or rocker arm; The oil supply port of the plunger head is moved far from the high pressure chamber to increase the distance that bubbles travel, and the upper wall of the outer plunger is connected to the notch at the open end of the inner plunger between the high pressure chamber and the fuel supply port. In addition, since a bubble discharge communication port leading to the outside of the valve lash adjuster is provided, most of the air bubbles in the hydraulic oil from the oil supply circuit are removed from the hydraulic valve lash adjuster to the outside before reaching the high pressure chamber. can be discharged.

In addition, since the orifice at the bottom of the inner plunger is shaped like a tube and protrudes a predetermined distance into the reservoir chamber, air bubbles that have not passed through the notch at the open end of the plunger head and the air bubble discharge communication port of the outer plunger are removed from the top of the tubular orifice. Air bubbles can be trapped in a reservoir between the outer surface of the wall and the inner surface of the upper wall of the outer plunger.

[Brief explanation of the drawing]

Figure 1 shows a typical horizontally opposed engine.
FIG. 3 is a layout diagram of a DOHC valve train. Figure 2 is a layout diagram of the OHC valve system of a typical transverse engine. FIG. 3 is a sectional view of the hydraulic valve lash adjuster of the present invention. FIG. 4 is a cross-sectional view of the hydraulic valve lash adjuster of the present invention installed in the rocker arm. 1...Hydraulic valve lash adjuster, 2...
... Rocker arm, 5 ... Cylindrical outer plunger, 6 ... Plunger head, 7 ... Cylindrical inner plunger, 8 ... Check valve, 12 ... Oil supply circuit, 14 ... Oil inlet, 15 ... Oil supply port ,1
6...Notch, 18...Bubble discharge communication port, 1
9...Bubble collection chamber, 20...Gap, 22...Bubble reservoir, 23...Reservoir chamber, 24...High pressure chamber, 3
1... Tubular orifice, 32... Bottom.

Claims (1)

[Scope of utility model registration request] In the cylinder that communicates with the engine oil supply circuit,
It has a cylindrical outer plunger fitted in an inclined position with a gap leading to the outside, and a cylindrical inner plunger with an orifice at the bottom is slidably fitted into the outer plunger. A plunger head is placed in the plunger head, an open end of the plunger head having a notch abuts the open end of the inner plunger opposite the orifice, and a bottom portion of the inner plunger has a plunger head formed in the inner plunger and the plunger head. In a hydraulic valve latch adjuster in which a check valve is arranged to allow hydraulic oil to flow only from the reservoir chamber to the high pressure chamber formed by the bottom of the inner plunger and the outer plunger, The plunger is provided with an oil inlet communicating with the engine oil supply circuit near its open end on the side opposite to the high pressure chamber, an oil inlet to the reservoir chamber is formed in the plunger head in alignment with this, and an oil inlet to the reservoir chamber is formed in the plunger head. A bubble discharge communication port is provided in the upper wall of the outer plunger connected to the oil inlet in alignment with the notch of the plunger head, and the bubble discharge communication port is formed on the outer peripheral surface of the outer plunger and is connected to the gap. A hydraulic valve lash adjuster characterized in that the orifice of the inner plunger from the reservoir chamber to the high pressure chamber is opened into an annular air bubble collection chamber communicating with the reservoir chamber, and the orifice of the inner plunger from the reservoir chamber to the high pressure chamber is protruded into the reservoir chamber by a predetermined distance.