JPH0223216A - Hydraulic rush adjustor - Google Patents

Abstract

PURPOSE:To prevent air from mixing into oil by forming a through-hole at a higher position of a rocker arm than a level of required rate of oil in an inner oil chamber so provided as to be horizontal at the time of closing of a valve, and forming an air bleeder port in communication with the through hole. CONSTITUTION:A hydraulic rush adjustor, provided on a rocker arm 20 of a valve system of a horizontal opposed engine, is composed of a bottomed cylindrical body 11 having an oil port 15 on a bottom 11a thereof, a plunger 12 inserted therein to partitioningly forming a high pressure chamber 13, a check valve 16 opening/closing the oil port 15 in the high pressure chamber 13, and the like. An inner oil chamber 10 is arranged in an oil reservoir 22 formed on the rocker arm 20, into which chamber oil is supplied through an oil introducing passage 23. A through-hole 1 is formed on a chamber side wall 10a located at a higher position than a level H of a required rate of oil in the chamber 10 for communication with the oil introducing passage 23, while an air bleeder port 2 is formed in communication with the through-hole 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an improvement in a hydraulic lash adjuster that automatically corrects a valve gap in a valve train for an internal combustion engine using hydraulic pressure and elastic force of an elastic member.

[Conventional technology]

A valve train in an internal combustion engine is generally susceptible to wear and thermal expansion, and the valve clearance changes during operation. Therefore, hydraulic lash adjusters have come into use to appropriately correct this gap.

FIG. 3 shows an example of this hydraulic lash adjuster, which includes the rocker arm 2.
It is arranged so as to fit into a lash adjuster support hole 21 provided at 0.

To explain the structure in detail, the body 11 of the hydraulic lash adjuster is composed of a bottomed hollow cylinder having a closed bottom part 11a and an open end on the opposite side, and a plunger 12 is fitted into the hollow part. The plunger 12 has a portion extending outwardly therefrom. A high pressure chamber 13 is formed between the body bottom 11a and the plunger 12, and an elastic body 14 is interposed within the high pressure chamber 13 to urge the plunger 12 toward the open end of the body 11. The body bottom 11a has an oil hole 15 for introducing oil from the outside.
A check valve 16 and a check valve cage 17, which control the opening and closing of the oil hole 15, are connected to the high pressure chamber 13.
It is located inside. Furthermore, the oil reservoir chamber 22 is located at the bottom of the body 1.
It is provided inside the rocker arm 20 adjacent to 1 a and connected to the high pressure chamber 13 via an oil hole 15 . Oil supplied to such a hydraulic lash adjuster is supplied from an oil guide path 23 provided in the rocker arm 20, and is led to the high pressure chamber 13 via the oil reservoir chamber 22.

Since the outer end of the plunger 12 is placed in contact with the valve 30, the rocker arm 2
When actuated, valve 30 is pushed out through the hydraulic lash adjuster.

At this time, if the check valve 16 closes the oil hole 15 and stiffens the oil trapped in the high pressure chamber 13,
Thereafter, the plunger 12 moves together with the rocker arm 20 to push out the valve 30, opening the valve. Further, when the valve is closed, the valve 30 is seated as the rocker arm 20 rotates, and the force of the valve spring 31 on the plunger 12 is eliminated. Therefore, the plunger 12 slides toward the opening end of the body 11 due to the repulsive force of the elastic body 14 in the contracted state, and the hydraulic lash adjuster is operated until the gap in the valve mechanism caused by thermal deformation or the like is reduced to zero. Stretch and correct.

[Problem that the invention seeks to solve]

As is well known, in order for the hydraulic lash adjuster to maintain normal operation, it is necessary for the oil in the high pressure chamber 13 to maintain its rigidity at all times, and for this reason, the oil introduced into the high pressure chamber 13 is free from air. Please be very careful.

However, the valve 30 may be in an open state when the multi-cylinder engine is stopped, and at this time the valve spring 31 of the valve 30 continues to apply a load to the plunger 12 of the lash adjuster. Therefore, the plunger 12 continues to contract into the body 11, and the oil in the high pressure chamber 13 leaks out from the gap between the body 11 and the plunger 12. If the engine is restarted in such a state and oil is rapidly introduced into the high pressure chamber 13 during the first cam cycle, if the oil level in the oil reservoir chamber 22 is low and the oil amount is insufficient, the engine will While the engine is stopped, oil is not supplied from the oil guide path 23, so oil mixed with a large amount of air is led to the high pressure chamber 13, resulting in an extreme decrease in the rigidity of the oil.

Therefore, conventionally, a hollow cylindrical inner oil chamber 10 with one end opened to the oil hole 15 is provided in the oil reservoir chamber 22, as shown by the dotted chain line in FIG. 3.

A necessary amount of oil (hereinafter referred to as "required oil amount") to prevent air from being mixed into the oil when the engine is restarted is secured in the inner oil chamber. Furthermore, an oil injection hole 18 into the chamber 10 is provided as high as possible to ensure the amount of oil, and an air vent hole 19 is provided at the top of the chamber 10 to vent air.

However, if these valve mechanisms are used as they are in horizontally opposed or V-type machines, oil may drain out from the injection hole 18 while one engine is stopped, or oil may leak from the air vent hole 19 during operation. The required amount of oil cannot be secured. That is, in the above-mentioned engine, since the cylinder is installed in a horizontal or tilted state, the valve 30, the plunger 12 of the valve mechanism that presses the valve to open and close it, the oil reservoir chamber 22, and the inner The oil chamber 10 is also often installed in a horizontal or tilted state.

Therefore, depending on the stop position of the rocker arm 20, the oil level H in the inner oil chamber 10 may be above the injection hole 18 as shown in FIG. Due to the movement, the oil in the inner oil chamber 10 is removed from the air vent hole 1 near the oil level H.
9, and the necessary amount of oil cannot be secured.

The present invention has been made to solve the above-mentioned problems. In particular, the inner oil chamber of a hydraulic lash adjuster is provided so as to be horizontal when the valve is closed, or the inner oil chamber is provided so that the inner oil chamber is oriented horizontally when the valve is closed. In the case where the inner oil chamber is inclined with its opening facing downward, the structure of the inner oil chamber is improved and the oil drains out.
This prevents leakage and ensures a sufficient amount of oil.

[Means to solve the problem]

Therefore, as shown in FIG. 1, the present invention has an inner oil chamber lO in the oil reservoir chamber 22, and the inner oil chamber 10 is provided in a horizontal direction when the valve is closed, or The target is a hydraulic lash adjuster in which the oil chamber 10 is inclined so that its opening faces downward when the valve is closed, and the chamber is always located at a higher level than the oil level H of the required oil amount in the inner oil chamber 11. A through hole 1 is provided in the side wall 10a, and oil is supplied from the oil guide path 23 through the through hole 1, and the oil reservoir chamber 2
The basic feature is that an air vent hole 2 is provided which communicates with the through hole 1 from the rocker arm 2o outward.

Here, set the installation position of the through hole l to the inner oil chamber l.
The reason why the chamber side wall 10a is always at a higher level than the oil level H of the required amount of oil in the inner oil chamber 10 is because the oil level H apparently changes its position within the inner oil chamber 10 due to the swinging of the rocker arm 20. This is because even if the rocker arm 20 stops at an arbitrary position, the position of the through hole 1 is not lower than the oil level H to prevent oil from draining out.

[Effect]

The through hole 1 serves both for air venting and oil supply in the inner oil chamber 10, and as mentioned above, it is provided on the chamber side 110a which is always higher than the oil level H.
Oil no longer leaks from there, and even when the engine is restarted without oil being supplied from the oil guide path 23, the inner oil chamber 10 has the required amount of oil (a sufficient amount of oil without air being mixed in). will be ensured. At the same time, the air in the inner oil chamber 10 is released through the through hole 1 and the air vent hole 2 at any time.

〔Example〕

FIG. 2 is an enlarged sectional view showing a center pivot rocker arm 20 attached as a valve operating mechanism of a horizontally opposed engine and a hydraulic lash adjuster according to an embodiment of the present invention attached to the center pivot rocker arm 20. In the figure, 20a is a rocker shaft, and 23 is an oil guide path that leads oil from the rocker shaft 20a to the hydraulic lash adjuster.

The hydraulic lash adjuster of this embodiment is fitted into a lash adjuster support hole 21 bored at the end of a rocker arm 20, and includes a bottomed hollow cylindrical body 11 having an oil hole 15 at the bottom 11a, A plunger 12 is slidably fitted into the body 11 and forms a high pressure chamber 13 between it and the bottom 11a, and a plunger 12 is inserted into the high pressure chamber 13 and biased toward the open end of the body 1. The plunger spring 14a is also provided in the high pressure chamber 13 and the oil hole 1 is connected to the plunger spring 14a.
5 and a check valve cage 17 that holds the check valve 16. Further, an oil reservoir chamber 22 is provided at the back of the lash adjuster support hole 21 of the rocker arm 20 adjacent to the body bottom 11a, and one end of the oil reservoir chamber 22 is opened to the oil hole 15. A hollow cylindrical inner oil chamber 10 is provided.

Oil is supplied into the inner oil chamber 10 from the oil guide path 23 of the rocker arm 20.

As mentioned above, since this hydraulic lash adjuster is provided as a valve mechanism for a horizontally opposed engine, the plunger 12. The body 11, the oil reservoir 22, and the inner oil chamber 10 are oriented in the horizontal direction when the rocker arm 20 is stopped in the valve closed state, and are oriented in the horizontal direction when the rocker arm 20 is stopped in the valve open state. , it is inclined slightly downward (that is, the opening of the inner oil chamber 10 is inclined so as to face downward).

Oil is supplied into the inner oil chamber 10 from the oil guide path 23 through the through hole 1, but the rocker arm 20 swings, causing the oil level H to apparently change its position, causing the rocker arm 20 to stop at an arbitrary position. In order to prevent the through hole 1 from being at a position lower than the oil level H when the oil level is increased, the through hole 1 is provided in the chamber upper wall LOa, which is always at a higher position than the oil level H of the required oil amount. In this embodiment, an annular groove 24 is provided on the inner peripheral side of the oil reservoir chamber 22 of the rocker arm 20.
The oil that has passed through the oil guide path 23 flows into the groove 24 and is guided to the through hole 1.

The through hole 1 also serves as an air vent hole in the inner oil chamber 10, but in order to completely release the air to the outside of the rocker arm 20, the air vent hole 2 communicating with the through hole 1 is Rocker arm 20 from groove 24 of reservoir chamber 22
It is drilled outward.

These valve mechanisms operate as follows during engine operation. That is, the rocker arm 20 is connected to the rocker shaft 20
rocker arm 2 when the pulp valve 30 is opened.
0 rotates counterclockwise in the figure, and the plunger 12 slides inward of the body 11 by the force of the valve spring 31. At this time, when the check valve 16 closes the oil hole 15, the oil trapped in the high pressure chamber 13 becomes rigid, and the plunger 12 then moves together with the rocker arm to push out the valve 30. Conversely, when the valve is closed, the rocker arm 20 rotates clockwise, the force of the valve spring no longer acts, and the plunger spring 14a, which had been contracted until then, slides the plunger 12 toward the body opening end due to its repulsive force. Make it move.

At this time, if the amount of oil in the high pressure chamber 13 is insufficient, negative pressure is generated as the plunger 12 slides, and the check valve 16 moves away from the oil hole 15, causing the inner oil chamber 1
It will suck in oil from zero.

In order to keep the oil amount in the inner oil chamber 10 constant during engine operation, an oil guide path 23 is provided from the rocker shaft 20a to
The oil flowing through the annular groove 24 enters the inner oil chamber 10 through the through hole 1.

Further, air separated from the oil and accumulated in the inner oil chamber 10 is discharged to the outside through the through hole 1 and the air vent hole 2.

On the other hand, no matter what the state of the oil level H in the inner oil chamber 10 is, the through hole 1 is always at a higher level than the oil level I-1, so no oil drains out or leaks from the chamber 10. The required amount of oil is always ensured in the inner oil chamber IO. Therefore, the engine stops with the valve 30 remaining open, and some of the oil in the high pressure chamber 13 is removed from the plunger 1 by sliding of the plunger 12.
The hydraulic lash adjuster leaking from the gap between the inner oil chamber 10 and the body 11 sucks oil from inside the inner oil chamber 10, which has a sufficient amount of oil, when the oil is sucked into the high pressure chamber 13 when the engine is restarted. Air is not mixed into the high pressure chamber 13, and the rigidity of the oil in the high pressure chamber 13 does not decrease.

〔Effect of the invention〕

According to the hydraulic lash adjuster of the present invention described in detail above, the inner oil chamber is provided so as to be horizontal when the valve is closed, or the inner oil chamber is tilted so that its opening is directed downward when the valve is closed. Even if the inner oil chamber is provided with a Drainage of oil from inside is eliminated, and it is possible to accurately prevent air from getting mixed into the oil, which is caused by a lack of oil, which is likely to occur when oil is sucked into the high-pressure chamber when restarting the engine. Therefore, it is possible to effectively prevent problems such as deterioration in startability when starting the engine, occurrence of start noise, and progression of wear in various parts of the valve mechanism, which are caused by a decrease in oil rigidity due to air inclusion.

[Brief explanation of the drawing]

Fig. 1 is an enlarged sectional view showing the basic configuration of the present invention, Fig. 2 is an explanatory diagram of a valve train mechanism showing a hydraulic lash adjuster according to an embodiment of the present invention, and Fig. 3 is a diagram showing a conventional valve train mechanism. FIG. 4 is an enlarged sectional view showing a state in which the valve operating mechanism is used as it is in a horizontally opposed type or V-type machine. In the figure, 1 is a through hole, 2 is an air vent hole, IO is an inner oil chamber, 11 is a body, 12 is a plunger, 13 is a high pressure chamber, 14 is an elastic body, 15 is an oil hole, 16 is a check valve cage, and 20 is a rocker arm , 22 indicates an oil reservoir chamber, and 23 indicates an oil guide path. Diagram

Claims (1)

[Claims] A hollow cylindrical body with a bottom that is attached to the rocker arm and has an oil hole at the bottom; a plunger that is slidably fitted into the body and forms a high pressure chamber between the body and the bottom; an elastic body mounted therein to bias the plunger toward the open end of the body; a check valve also provided in the high pressure chamber for controlling opening and closing of the oil hole; a check valve cage holding the check valve; and adjacent to the bottom of the body. It consists of an oil reservoir chamber provided in the rocker arm, and a hollow cylindrical inner oil chamber provided within the oil reservoir chamber and having one end opened to the oil hole. In a hydraulic lash adjuster, the inner oil chamber is provided at an angle so that its opening faces downward when the valve is closed, and oil is supplied from the rocker arm to the inner oil chamber through the oil guide path. A through hole is provided in the side wall of the chamber, which is always at a higher level than the required oil level in the inner oil chamber, and oil is supplied from the oil guide path through this through hole, and from the oil reservoir chamber to the outside of the rocker arm. A hydraulic lash adjuster, characterized in that an air vent hole is provided that communicates with the through hole.