JPH0444804Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hydraulic valve latch adjuster that is fitted into a cylinder that communicates with an engine oil supply circuit.

[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 2 is a layout diagram of a DOHC type valve train for a typical horizontally opposed engine. In the figure,
1 is a hydraulic valve lash adjuster, 2 is a rocker arm, 3 is a cam, and 4 is a valve stem. The enlarged sectional view of FIG. 7 shows the configuration of a typical conventional hydraulic valve lash adjuster that is disposed in an inclined position at the bottom of this valve train.

As shown in the figure, the hydraulic valve latch adjuster 1 includes a cylindrical outer plunger or cylindrical body 5 fitted into a cylinder formed in a cylinder head 26 with a small gap 20 communicating with the outside. A cylindrical inner plunger 7 is fitted into the cylindrical outer plunger so as to be slidable in the axial direction with a small gap 25 therebetween, and has an orifice at the bottom, and one end having a notch or oil supply port 15. It has a plunger head 6 which abuts the open end of the cylindrical inner plunger 7, and whose other end or active end projects from the open end of the cylindrical outer plunger and abuts one end of the rocker arm 2.
The bottom of the inner plunger 7 is designed to allow oil to flow only 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 inner plunger 7 and the outer plunger 5. A check valve is located at the

In the illustrated inclined position, the reservoir chamber 23 is located diagonally below the high pressure chamber 24. Hydraulic oil is supplied from an oil supply circuit 12 provided in the cylinder head 26 through an annular oil introduction chamber 13 formed on the outer circumferential surface of the outer plunger, and an oil introduction port formed at a predetermined location on the wall of the outer plunger. 14 and the connecting groove 1 at the open end of the plunger head.
7 and the oil supply port 15 into the reservoir chamber 23 .

[Problem that the invention attempts to solve]

The hydraulic oil flowing into the reservoir chamber 23 from the oil supply circuit 12 usually has many bubbles. When the hydraulic valve latch adjuster is in the upright position as shown in Fig. 6, the air bubbles in the hydraulic oil that have flowed into the reservoir chamber 23 move upward in the reservoir chamber 23 due to buoyancy, and the air bubbles move upward in the reservoir chamber 23, causing the air bubbles to move upwards in the reservoir chamber 23 and to the plunger head. The oil exits the valve brush adjuster through an opening or drain port 16 provided at the top and through a gap between the outer circumferential surface of the plunger head and the inner circumferential surface of the cylindrical outer plunger. Furthermore, even if air bubbles enter the high pressure chamber 24, they will pass through the gap 25 between the inner circumferential surface of the outer plunger 5 and the outer circumferential surface of the inner plunger 7 due to the high pressure of the hydraulic oil in the high pressure chamber 24, and the air bubbles will enter the plunger head 6. It returns into the reservoir chamber 23 via the oil recovery port 41 at the open end.

However, in the tilted position shown in FIG. 7, the bubbles entering the reservoir chamber 23 enter the reservoir chamber portion of the inner plunger 7 due to their buoyancy, and then enter the high pressure chamber 24 during operation of the valve brush adjuster. It's going to get into it. The air bubbles that have entered the high pressure chamber enter the communication groove 17 of the plunger head as the hydraulic oil flows through the gap 25 between the inner peripheral surface of the outer plunger 5 and the outer peripheral surface of the inner plunger 7. By repeating this cycle, the air concentration in the upper part of the reservoir chamber 23 and in the high pressure chamber 24 gradually increases, and when it reaches a certain predetermined level, the rigidity of the valve brush adjuster decreases, causing a knocking sound from the valve train. This also caused the valve brush adjuster to malfunction.

In addition, in conventional hydraulic valve latch adjusters, during operation, the outer plunger may rotate relative to the inner peripheral surface of the cylinder of the cylinder head or rocker arm and the inner plunger. The alignment between the oil inlet 14, the communication groove 17 of the inner plunger, and the oil filler port 15 was poor, and the supply of hydraulic oil into the reservoir chamber was sometimes not carried out smoothly.

The purpose of the present invention was to solve the above problems, and to prevent air bubbles from entering the high pressure chamber located above the reservoir chamber as a whole, and to prevent relative rotation of the outer plunger with respect to the cylinder. An object of the present invention is to provide a hydraulic valve lash adjuster that has been improved.

[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, and an oil inlet to the reservoir chamber is formed in the plunger head in alignment with this;
Furthermore, a communication port for air bubble discharge is provided in the upper wall portion of the outer plunger between the high pressure chamber and the oil inlet in alignment with the notch of the plunger head, and the communication port for air bubble discharge is connected to the outer circumference of the outer plunger. Provided is a hydraulic valve lash adjuster, characterized in that a detent is provided to prevent relative rotation of the outer plunger with respect to the cylinder, opening into an annular air bubble collection chamber formed in the surface and communicating with the gap. do.

〔Example〕

The hydraulic valve lash adjuster of the present invention will be explained with reference to FIG. Figure 1 is similar to Figure 2.
The configuration of the lower hydraulic valve lash adjuster of the DOHC valve train is shown, and corresponds to FIG. 7 of the conventional example.

The hydraulic valve latch adjuster 1 is a cylindrical outer plunger or cylinder that is fixedly 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 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. The valve brush adjuster 1 further includes a cylindrical outer plunger 5 which 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, and which has an orifice at the bottom. One open end having a notch or opening 16 abuts against the open end of the inner plunger 7 and the other or working end protrudes from the open end of the cylindrical outer plunger to open the cam 3. It has a plunger head 6 which abuts one end of a rocker arm 2 which swings under action. The other end of the Rotsuker arm 2 is the valve stem 4
It is in contact with. 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 shown, the high pressure chamber 24 is comprised of a reservoir chamber 23 as a whole.
It is located above. 10 is retainer 9
The return spring 11, which is in contact with the bottom of the plunger 7 and the closed end of the main body 5 via the return spring 11, is a check valve spring held by a retainer 9.

According to the structural features of the hydraulic valve lash adjuster of the present invention, the cylindrical outer plunger 5
an annular oil introduction chamber 13 over its peripheral wall near its open end opposite the high pressure chamber 24 and communicating with an oil supply circuit 12 provided in the cylinder head;
and an oil inlet 1 at a predetermined location on the surrounding wall.
It has 4. In this embodiment, it is advantageous to form the oil inlet 14 on the upper wall of the outer plunger 5, but it may also be formed on the lower wall. On the other hand, the plunger head 6 is connected to the oil inlet 14 of the outer plunger 5.
Correspondingly, it has a communication groove 17b and a fuel filler port 15. It can be seen that the distance between the high pressure chamber 24 and the fuel filler port 15 is much longer in the present invention than in the conventional example shown in FIG. 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 bubble collection chamber 19 communicates with the gap 20 between the inner circumferential surface of the cylinder and the outer circumferential surface of the outer plunger 5 and thus with the outside of the hydraulic valve lash adjuster 1 .

Furthermore, the outer plunger 5 of the hydraulic valve lash adjuster of the present invention has a detent 31 in the form of a pin on its bottom outer surface. A detent receiving hole corresponding to the detent 31 is formed in the bottom surface of the cylinder. This detent 31 ensures reliable positioning of the outer plunger 5 and thus the valve brush adjuster relative to the cylinder during assembly. The detent 31 is also arranged to ensure that the oil inlet 14 and communication groove 17a of the plunger head 6 are aligned with the air bubble discharge communication port 18 of the outer plunger 5 during operation. Of course, the detent 31 may be provided on the bottom surface of the cylinder, and a cooperating detent receiving hole may be provided on the outer surface of the bottom of the outer plunger 5.

When the hydraulic valve latch adjuster operates, hydraulic oil containing a large amount of air bubbles is passed from the oil supply circuit 12 of the cylinder head through the oil inlet chamber 13 and oil inlet 14 of the outer plunger 5, and then to the plunger head 6. It flows into the reservoir chamber 23 through the communication groove 17b and the oil supply port 15. Bubbles move vertically due to their buoyancy. As mentioned above,
Since the distance between the high pressure chamber 24 and the oil supply port 15 is relatively long, the air bubbles, together with the hydraulic oil, do not enter the reservoir chamber of the inner plunger, but pass through the notch 16 of the plunger head and the communication groove 17a, and then enter the outer plunger. The air enters the air bubble collection chamber 19 through the air bubble discharge communication port 18 and is collected 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. Even if air bubbles were to enter the high pressure chamber 24, the air bubbles would be trapped between the inner circumferential surface of the outer plunger and the outer circumferential surface of the inner plunger together with a small amount of hydraulic oil due to the high pressure of the hydraulic oil within the high pressure chamber 24. It reaches the communication groove 17a through the gap 25, and then follows the above-mentioned route to exit the hydraulic valve lash adjuster.

Figure 3 shows a typical example of an OHC valve system for a horizontal engine. FIG. 4 shows, in cross section, a so-called Rocker arm internal type hydraulic valve lash adjuster as another embodiment of the present invention on the upper side of such 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. In FIG. 4, a rotation stop means different from the rotation stop 31 of FIG. 1 is shown. Referring to FIGS. 4 and 5, a part of the flange 5b at the open end of the outer plunger, which is attached to the rocker arm 2 in a liquid-tight manner, is cut out in a straight line, and the straight part of the flange is connected to the stepped part of the rocker arm. and thereby constitute a rotation stopper 31. Other points that differ from the one in FIG. 1 are that the annular air bubble collection chamber 19 of the outer plunger 5 is
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.

[Effects of the invention] According to the invention, in a hydraulic valve latch adjuster that is fitted into the cylinder of the cylinder head or rocker arm in an inclined position, the cylindrical outer plunger is connected to the oil supply circuit in the cylinder head or rocker arm. The oil inlet of the plunger head and the oil supply port of the plunger head are moved far from the high pressure chamber to increase the distance that bubbles travel. By providing a bubble discharge communication port that communicates with the notch and leads to the outside of the valve rush adjuster, most of the bubbles in the hydraulic oil from the oil supply circuit are removed from the hydraulic valve valve before reaching the high pressure chamber. It can be discharged to the outside from the shaft adjuster.

It also ensures accurate positioning during assembly of the outer plunger relative to the cylinder and prevents rotation of the outer plunger relative to the cylinder during operation and thus of the hydraulic valve latch adjuster relative to the cylinder. The anti-rotation mechanism not only maintains accurate alignment between the plunger head's oil supply port and the outer plunger's oil inlet at all times, but also allows communication between the notch at the open end of the plunger head and the outer plunger's air bubble discharge port. The openings are always aligned accurately, so that smooth hydraulic oil supply and air bubble discharge can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the hydraulic valve lash adjuster of the present invention. FIG. 2 is a layout diagram of a DOHC type valve train having a hydraulic valve lash adjuster according to the present invention. FIG. 3 is a layout diagram of an OHC type valve train having a hydraulic valve latch adjuster built into a rocker arm according to the present invention. Fourth
The figure is a sectional view of the rocker arm internal type hydraulic valve latch adjuster of the present invention. FIG. 5 is a bottom view of the hydraulic valve latch adjuster of FIG. 4 showing a modification of the rotation stopper of the present invention.
FIG. 6 is a schematic cross-sectional view of a conventional hydraulic valvelash adjuster shown in an upright position. Figure 7 shows
FIG. 7 is a cross-sectional view of the hydraulic valve latch adjuster of FIG. 6 inserted into the cylinder in an inclined position; 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... Air bubble collection chamber, 20... Gap, 23... Reservoir chamber, 24... High pressure chamber, 31... Rotation stopper.

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 further, an oil inlet to the reservoir chamber is formed in the plunger head. and an air bubble discharge communication port is provided on the upper wall of the outer plunger between the oil inlet and the oil inlet, aligned with the notch of the plunger head;
The air bubble discharge communication port is opened to an annular air bubble collection chamber formed on the outer peripheral surface of the outer plunger and communicated with the gap, and a detent is provided to prevent relative rotation of the outer plunger with respect to the cylinder. Features a hydraulic valve lash adjuster.