JPH0526242Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a rocker arm with an internal hydraulic valve brush adjuster for an internal combustion engine.

[Conventional technology]

In recent years, it has become known to use a hydraulic valve lash adjuster incorporated into a rocker arm in a valve train of an internal combustion engine.

In such a valve brush adjuster, a high pressure chamber formed between the plunger and the adjuster body communicates with an oil passage in the rocker arm via a check valve provided in an oil inlet of the valve brush adjuster. This oil passage communicates with the annular oil groove between the rocker arm and the rocker shaft at its upper portion. The annular oil groove communicates with an oil supply passage formed in the rocker shaft and communicating with the oil pump through the through hole of the rocker shaft.

On the other hand, since the valve lash adjuster is located far away from the oil pump, it will operate without the supply of hydraulic oil from the oil pump when the engine is started. It is necessary to cover the demand for hydraulic oil, so a reservoir chamber as an oil reservoir is installed inside the valve brush adjuster, or a part of the oil passage in the rocker arm is expanded near the valve brush adjuster. Countermeasures such as using an oil sump are known.

[Problem that the invention attempts to solve]

In the conventional hydraulic valve latch adjuster built-in type rocker arm described above, when the engine is stopped with the valve open, or in other words, with the biasing force of the valve spring still acting on the plunger, the plunger gradually moves toward the adjuster body. The hydraulic oil in the high pressure chamber flows out to the outside or into the oil passage by the amount by which the volume of the high pressure chamber is reduced. Then, when the engine is restarted and the valve closes, the high-pressure chamber rapidly increases its volume and draws in a large amount of hydraulic oil from the oil sump.

However, if the engine stops and starts several times in a relatively short period of time due to an engine misfire, etc., the valve brush adjuster may draw air into its high pressure chamber due to a lack of hydraulic oil. It will end up being gone. This is because the oil passage of the Rocker arm communicates with the upper part of the annular oil groove, so the air that enters the annular oil groove from the oil supply path of the Rocker shaft through the through hole moves upwards of the annular oil groove due to buoyancy. This is because even if this air does not reach the valve rush adjuster in one engine stop/start cycle, it will enter the high pressure chamber in the next cycle. Intrusion of air into the high-pressure chamber causes the valve train to make a clicking noise, and also applies abnormal stress to the valve train, impairing its function.

As a measure to prevent air from entering the high-pressure chamber, an oil reservoir in or near the valve brush adjuster contains 3 to 5 times the amount of hydraulic oil required by the high-pressure chamber when starting the engine. It is conceivable to expand the capacity as much as possible, thereby preventing a shortage of hydraulic fluid even after several engine stop/start cycles. However, with this measure,
The larger end of the rocker arm increases the inertial weight of the rocker arm as a whole, which has the disadvantage of deteriorating the followability of the valve brush adjuster during high-speed operation. In addition, this countermeasure applies to valve brush adjusters that are installed at an almost horizontal angle, or where the reservoir chamber is located below the high pressure chamber, where air tends to move to the upper part of the reservoir chamber and accumulate there. However, the problem of air intrusion into the hyperbaric chamber still arose.

The purpose of this invention is to prevent air from entering the high-pressure chamber even if the engine is stopped and started several times in a relatively short period of time, and to prevent the valve thrust from increasing without increasing the inertial weight of the rocker arm. To provide a hydraulic valve latch adjuster built-in type rocker arm capable of supplying a sufficient amount of hydraulic oil to an adjuster.

[Means for solving the problem] In order to achieve this purpose, according to the present invention,
A rocker shaft with an internal oil supply passage is rotatably equipped with a rocker arm incorporating a hydraulic valve latch adjuster, and the oil supply passage of the rocker shaft connects the rocker shaft and rocker arm through a through hole provided near the top of the rocker shaft. An oil sump is provided in the lower part of the annular oil groove in communication with the annular oil groove, and the oil sump is connected to an oil passage leading to an oil inlet of a hydraulic valve brush adjuster. To provide a hydraulic valve lash adjuster built-in rocker arm characterized by communication.

〔Example〕

An embodiment of the rocker arm with an internal hydraulic valve lash adjuster according to the present invention will now be described in detail with reference to FIG.

The rocker arm 1, which is rotatably attached to the hollow rocker shaft 2, is equipped with a hydraulic valve lever adjuster 10 at one end thereof, which adjusts the overall movement according to the orientation or arrangement of various types of engines developed in recent years. The rocker arm 1 is installed in a substantially horizontally inclined position, and the cam 3 is in contact with the other end of the rocker arm 1.

The illustrated valve brush adjuster 10 is of a known type having a reservoir chamber inside.The structure will be briefly explained below.The adjuster body 10a of the valve brush adjuster is fitted into the mounting hole of the rocker arm. Inside the adjuster body is a plunger 1 with an orifice at the bottom.
0b is slidably fitted. Plunger 1
A plunger head 10b' is disposed within the adjuster body 10a in contact with the open end of the plunger 0b, a reservoir chamber 10h is formed between the plunger and the plunger head, and a high pressure chamber 10e is provided.
is formed between the adjuster body and the plunger. 10d is a check valve provided at the orifice of the plunger to allow hydraulic oil to flow only from the reservoir chamber 10h to the high pressure chamber, and 10c is a check valve that is connected to the bottom of the plunger and the bottom of the adjuster body via the retainer 10g. This is the return spring that is in contact with the A valve stem 12 is in contact with the outer end of the plunger head 10b', and 13 is a valve spring.

On the other hand, the rocker shaft 2 is internally equipped with an oil supply passage 4 communicating with an oil pump (not shown), and an annular oil groove 6 formed between the rocker arm 1 and the rocker shaft 2 is provided near the top of the rocker shaft. It communicates with the oil supply passage 4 through a through hole 5 . As shown in the figure, a dome-shaped recess 7 is formed at the bottom of the annular oil groove 6 in communication with the annular oil groove 6 as a whole, and this recess 7 serves as an oil reservoir for the valve brush adjuster 10. It communicates with the oil introduction part 10f of the valve brush adjuster via the oil passage 8 inside.

FIG. 2 shows a truncated conical oil sump 7' as a variant. The oil sump can have any various shapes depending on the processing conditions. The other components in FIG. 2 are the same as those in the embodiment shown in FIG. In any case, according to the present invention, the amount of hydraulic oil in the oil reservoir is 3 to 5 times the amount of hydraulic oil required by the high pressure chamber when starting the engine once, or
It can be expanded to accommodate seven times the amount of hydraulic fluid when the oil pump is slow to supply hydraulic fluid, thereby ensuring that even several engine stop-start cycles will not result in a shortage of hydraulic fluid. be able to.

Furthermore, in the present invention, since the oil passage communicates with the annular oil groove via the oil reservoir 7 or 7' at the bottom of the annular oil groove, even if air enters the annular oil groove, buoyancy will cause the oil passage to flow into the annular oil groove. , so that no air can enter into the oil passage and thus into the high pressure chamber of the valve brush adjuster. In this embodiment, the through hole is provided in the upper part of the rocker shaft, but it is clear that the position of the through hole is not necessarily limited to the upper part of the rocker shaft since air always moves upward due to buoyancy.

Next, the operation of the hydraulic valve lash adjuster built-in type rocker arm of the present invention will be explained. still,
The operation of the valve brush adjuster itself is well known and will not be described in detail.

The biasing force of the valve spring 13 is the plunger 1
When the engine is stopped with the pressure 0b still acting, the plunger is pushed into the adjuster body 10a, and the hydraulic oil in the high pressure chamber 10e flows out to the outside by the amount of the reduced volume of the high pressure chamber. Moreover, the hydraulic oil in the oil supply path 4 is drawn back to the oil pan. When the engine is then restarted and the valve is closed, the high pressure chamber rapidly increases its volume and draws in a large amount of hydraulic fluid from the reservoir chamber. Even if the engine is stopped and started several times due to an engine misfire or the like, the oil reservoir 7 or 7' can supply a sufficient amount of hydraulic oil to the high pressure chamber of the valve brush adjuster. Therefore, the valve brush adjuster will never run out of hydraulic oil. Furthermore, even if air enters the annular oil groove, it will move to the upper part of the annular oil groove due to buoyancy, so it will not enter the high pressure chamber of the valve brush adjuster through the oil passage.

[Effect of idea]

As described above, the present invention provides an oil reservoir of a predetermined capacity in communication with the annular oil groove at the bottom of the annular oil groove between the rocker arm and the rocker shaft, and connects the oil reservoir and the oil introduction part of the valve brush adjuster to the rocker arm. Because they communicate with each other through the oil passages inside, the inertial weight of the rocker arm does not increase, and a sufficient amount of hydraulic oil can be supplied to the valve brush adjuster even if the engine is stopped and started several times. This prevents air from entering the high pressure chamber of the valve brush adjuster.

Furthermore, even if air enters the annular oil groove, it will move to the upper part of the annular oil groove and will not enter the valve brush adjuster.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the rocker arm of the present invention incorporating a hydraulic valve lash adjuster. FIG. 2 is a schematic sectional view of a rocker arm with an internal hydraulic valve latch adjuster as a modified example of the present invention. List of main reference numbers, 1...Rotsuker arm, 2...Rotsuker shaft, 4...Refueling path, 5
...Through hole, 6...Annular oil groove, 7, 7'...Oil reservoir, 10...Hydraulic valve brush adjuster.

Claims (1)

[Scope of utility model registration request] A rocker shaft with an internal oil supply passage is rotatably equipped with a rocker arm incorporating a hydraulic valve latch adjuster, and the oil supply passage of the rocker shaft connects the rocker shaft and rocker arm through a through hole provided near the top of the rocker shaft. An oil sump is provided in the lower part of the annular oil groove in communication with the annular oil groove, and the oil sump is connected to an oil passage leading to an oil inlet of a hydraulic valve brush adjuster. A hydraulic valve latch adjuster internal type rotscar arm that is characterized by being in communication.