JPH041163B2 - - Google Patents

Abstract

PURPOSE:To enable to release a leaked hydraulic oil from an oil reservoir of a clearance eliminating unit directly to outside and assure the smooth pivoting of a rocker shaft in a device in which a valve head clearance is automatically eliminated by the utilization of a hydraulic loading and a valve moving mechanism is silently operated. CONSTITUTION:An eccentric shaft 8 is formed on a rocker shaft 2 on which a journal 7 is releasably supported by a bearing hole 10 of an engine block B in freely rotatable manner, a rocker arm 11 is releasably supported by the eccentric shaft 8 in freely swingable manner in the title device. A hydraulic clearance eliminating unit Z is adjacently provided with a notch 14 arranged on the outer surface of the jouranal 7, the eccentric shaft 8 is pivoted in the direction eliminating the valve head clearance at the valve closing time of intake and exhaust valves Vi, Ve, then the pivoting of the eccentric shaft 8 is obstructed during the valve opening period. In this case, an oil chamber 33 is formed to be faced to the end surface of the journal 7 in said bearing hole 10, the oil chamber 33 is made to be opened to the outside via an escape hole 34. Thereby, the leakage of the hydrauric oil from the oil reservoir in said unit Z is made directly releasable to the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a hydraulic gap elimination unit in the valve mechanism of an engine, automatically eliminates the valve head gap by using hydraulic pressure, and constantly operates the valve mechanism quietly. The present invention relates to a valve head gap eliminating device in a valve train.

The applicant has already proposed the following device as this type of device. That is, the rocker shaft, which rotatably supports the journal in the bearing hole of the engine block, is formed with an eccentric shaft that is offset by a certain amount from the center of rotation of the shaft, and the rocker arm that transmits the valve opening force of the camshaft to the valve is formed as described above. The eccentric shaft is swingably supported, and a notch is provided on the outer peripheral surface of the journal, and in this notch, the eccentric shaft is rotated in a direction that eliminates the valve head gap when the valve is closed, and when the valve is opened, the eccentric shaft is rotated in a direction that eliminates the valve head gap. A hydraulic gap eliminating unit for preventing rotation of the rocker is connected to the rocker shaft, and this gap eliminating unit includes:
An oil hole is provided that communicates with the oil reservoir inside the oil hole and opens into the notch. According to this device,
The gap elimination unit has good response because it does not apply reciprocating motion, and even when the engine is running at high speed, it can reliably eliminate the valve head gap and operate the valve mechanism quietly. Since there is no need to protrude an operating arm for rotation, the structure is simple and compact, and the journal of the rocker shaft is lubricated by the oil that leaks from the oil sump chamber of the gap elimination unit into the bearing hole along with air bubbles. It is possible to achieve effects such as:

However, in the above device, in order to improve the responsiveness of the hydraulic gap elimination unit, hydraulic oil at a predetermined pressure is supplied from the oil pump to the oil sump chamber in the unit. When the pressure of the pressure oil leaking into the bearing hole acts on the journal end face of the rocker shaft, a thrust load is applied to the rocker shaft, causing a disadvantage that the rotational resistance thereof increases to some extent.

An object of the present invention is to provide the valve head gap eliminating device which has been improved so that such inconveniences do not occur. An oil chamber is formed therein, and the end surface of the journal faces the oil chamber, and this oil chamber is opened to the outside through a relief hole.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, in FIG. It has a front engine block B ₁ and a rear engine block B ₂ arranged in a V-shape in the longitudinal direction of the vehicle, with a V between both engine blocks B ₁ and B ₂ .
In the character-shaped space S, these engine blocks B ₁ ,
A carburetor Ca that supplies air-fuel mixture to _B2 and a lubricating oil pump (not shown) provided at the bottom of the crankcase C extend from the discharge port and are connected to both engine blocks.
Lubricating oil is guided to the top of B ₁ and B ₂ through Y-shaped oil supply pipe P.
will be placed.

As shown in Fig. 2, engine block B ₁ (same for engine block B ₂ ) has two intake valves Vi and one exhaust valve Ve per cylinder, and a valve train M that opens and closes these valves. It is equipped with
This mechanism M is provided in a valve operating chamber H formed at the top of the engine block _B1 .

To explain the valve train mechanism M in detail with reference to FIGS. 2 to 6, the valve train chamber H includes one camshaft 1 and two coaxially arranged intake rocker shafts 2i.
and one exhaust rocker shaft 2e are arranged parallel to each other. The camshaft 1 is supported between a cylinder head 3 and a camshaft holder 4 constituting an engine block _B1 , and is rotationally driven by a crankshaft (not shown) via a timing transmission 5. On the other hand, each rocker shaft 2i, 2e has a small diameter journal 6 on the inner end side,
It is composed of a large diameter journal 7 on the outer end side and an eccentric shaft 8 occupying an intermediate position between them, and the small diameter journal 6 and the large diameter journal 7 are rotated in bearing holes 9 and 10 provided in the camshaft holder 4, respectively. The rocker arm 11 is freely supported and is supported by an eccentric shaft 8.
is swingably supported.

The camshaft 1 is equipped with two intake cams 12i and one exhaust cam 12e. The intake valve Vi and the exhaust valve Ve are connected via a rocker arm 11 supported on the eccentric shaft 8 of the intake rocker shaft 2i and the exhaust rocker shaft 2e, respectively.

Next, I will explain the valve head gap elimination device.
Since the valve head clearance devices for the intake and exhaust valves Vi and Ve basically have the same structure, the exhaust valve Ve system will be described as a representative.

The eccentric shaft 8 of the rocker shaft 2e is formed to be eccentric by a certain amount from the rotation center of the rocker shaft 2e, and when it rotates in the direction of arrow R around the rotation center of the rocker shaft 2e in FIG. 12
e and the exhaust valve Ve side. Further, a large notch 14 and a small notch 15 are provided on the outer periphery of the large diameter journal 7 of the rocker shaft 2e, and are opposed to each other with the center of rotation of the rocker shaft 2e in between.
At 4, a hydraulic gap eliminating unit Z is connected to the rocker shaft 2e, and at a small notch 15, a pressing rod 16 is connected to the rocker shaft 2e.

As clearly shown in FIG. 5, the hydraulic gap elimination unit Z has a cylinder 17 and a plunger 18 which slides on the cylinder 17 and defines a hydraulic chamber 19 therein. Support holes 20 provided in the corresponding engine blocks B ₁ and B ₂
The plunger 18 has its outer spherical end 18e in contact with the ceiling wall 14a of the large cutout 14, but the contact point is spaced apart from the center of the rocker shaft 2e by a certain distance in the radial direction. Plunger 18
is provided with an oil reservoir chamber 21 and a valve hole 22 that communicates this oil reservoir chamber 21 with the hydraulic chamber 19. It is connected to the oil supply passage 25 via the oil supply passage 25, and is always filled with pressure oil sent from the oil supply passage 25.

A hat-shaped valve cage 26 is fitted into the inner end of the plunger 18, and a spherical check valve 2 that opens and closes the valve hole 22 is fitted into the valve cage 26.
7 and a valve spring 28 for biasing it in the valve closing direction are housed in the check valve 27, and the check valve 27 is configured to open when the pressure in the hydraulic chamber 19 is reduced and close when the pressure increases. Furthermore, an extrusion spring 29 is contracted in the hydraulic chamber 19 and urges the plunger 18 to protrude above the cylinder 17.

On the other hand, the pressing rod 16 is brought into contact with the bottom wall of the small notch 15, and its contact point is spaced a certain distance from the center of rotation of the rocker shaft 2e. An auxiliary spring 30 is connected to this pressing rod 16 to press it in the direction of contact with the rocker shaft 2e.

Therefore, the spring force of the push spring 29 and the auxiliary spring 30 is set to be much weaker than that of the valve spring 13 of the exhaust valve Ve, and the push spring 29 is pushed through the plunger 18, and the auxiliary spring 30 is pushed A couple of forces in the direction of the arrow R are applied to the rocker shaft 2e through the rods 16, but since the directions of the forces of both springs 29 and 30 are opposite, the rocker shaft 2e does not receive any side load and rotates smoothly. can do.

An oil hole 31 connected to the oil reservoir chamber 21 is opened in the outer end surface of the plunger 18 in order to remove bubbles from the oil reservoir chamber 21 and to lubricate the spherical end portion 18a and the large diameter journal 7.

The outer end of the bearing hole 10 of the large diameter journal 7 has a blind cover 3
An oil chamber 33 is defined between the blind cover 32 and the end surface of the large-diameter journal 7, and this oil chamber 33 is opened to the valve train chamber H through a relief hole 34. The relief hole 34 is opened at a location where the valve mechanism M can be lubricated by the oil discharged from the hole.

As shown in Figure 6, from the hydraulic pump to the oil supply pipe P
The oil pumped into the oil passage 35 is divided into a lubricating oil passage 36 and a hydraulic oil passage 37, and the oil flowing into the lubricating oil passage 36 passes through a vertical hole 38 and a horizontal hole 39 provided in the rocker shaft 2e. The oil is supplied to the bearing hole 40 of the rocker arm 11, then flows out from the oil hole 41 provided in the rocker arm 11 and is supplied to the circumferential surface of the cam 12e.On the other hand, the oil that has flowed into the hydraulic oil passage 37 is supplied to the defoaming chamber 4.
2 from the oil supply path 25 to the gap elimination unit Z.
The oil is sent to the oil sump chamber 21. The defoaming chamber 42 weakens the flow rate of oil passing through the chamber,
The air bubbles mixed therein are floated up and discharged from the relief hole 43, thereby making it possible to supply good working oil containing almost no air bubbles to the oil reservoir chamber 21.

The relief hole 43 is formed as an orifice so that the oil pressure in the oil reservoir chamber 21 does not fall below a predetermined value due to the leakage of pressure oil together with air bubbles, and the leaked oil flows through the valve mechanism M. An opening is made in a place that provides lubrication.

Next, to explain the operation of this embodiment, the exhaust valve
When Ve is closed, the spring 29 is pushed out via the rocker shaft 2e, the plunger 18, and the pressing rod 16.
The couple of forces received from the auxiliary spring 30 causes the rocker arm 11 to rotate in the direction of the arrow R in FIG. The head gap, that is, the gap between the rocker arm 11, the cam 12e, and the exhaust valve Ve at each joint is eliminated.

At this time, if the pressure in the hydraulic chamber 19 is reduced by the pushing action of the pushing spring 29 against the plunger 18, the check valve 27 opens, so that the oil in the oil reservoir chamber 21 is replenished into the hydraulic chamber 19 through the valve hole 22, and the hydraulic chamber 19 is refilled. 19 is reliably filled with oil.

Next, when a valve opening force is applied to the rocker arm 1 due to the lift action of the cam 12e, the valve opening force also acts on the eccentric shaft 8 as a couple in the opposite direction to the arrow R.
This couple pushes the plunger 18 toward the hydraulic chamber 19, but since the check valve 27 remains closed, hydraulic pressure is generated in the hydraulic chamber 19. This hydraulic pressure prevents the plunger 18 from sliding, and the eccentric shaft 8
The rotation of the rocker shaft 2e is also prevented. As a result, the rocker arm 11 swings about the eccentric shaft 8 and opens the exhaust valve Ve against the force of the valve spring 13.
During this time, the oil in the hydraulic chamber 19 leaks slightly from between the sliding surfaces of the cylinder 17 and the plunger 18, but this leakage is absorbed into the oil reservoir chamber when the exhaust valve Ve is closed next time.
It is replenished from 1.

When bubbles are generated in the oil in the oil reservoir chamber 21 of the gap elimination unit Z, the bubbles float to the surface and flow out from the oil hole 31 to the large cutout 14 of the rocker shaft 2e together with a part of the pressure oil in the oil reservoir chamber 21. , air bubbles are prevented from entering the hydraulic chamber 19. At that time, the amount of pressure oil flowing out from the oil reservoir chamber 21 to the large notch 14 is limited by the large notch 14 that covers the opening of the oil hole 31.
The oil pressure in the oil reservoir chamber 21 did not drop significantly,
Therefore, when the check valve 27 is opened, hydraulic oil can be quickly replenished from the oil reservoir chamber 21 to the hydraulic chamber 19.

The air bubbles and oil that leaked into the major notch 14 are removed from the rock shaft 2.
Those that have entered the gap between the large-diameter journal 7 and the bearing hole 10 of e and flowed toward the eccentric shaft 8 are directly discharged into the valve train chamber H, and those that flowed to the opposite side are temporarily discharged into the oil chamber 33. After entering, it is discharged into the valve operating chamber H through the relief hole 34. During this time, the large-diameter journal 7 is lubricated by the oil, and oil to continue the lubrication is appropriately stored in the oil chamber 33. but,
The oil chamber 33 is maintained at approximately the same pressure as the valve chamber H by communicating with the valve chamber H through the relief hole 34, so that the oil stored in the oil chamber 33 exerts a thrust load on the rocker shaft 2e. It will not affect you.

The above-mentioned actions are performed similarly for the intake valve Vi system.

In the embodiment described above, if the relief holes 34 are provided in the rocker shafts 2i and 2e and communicated with the journal outer peripheral surface of the shafts and the bearing hole of the rocker arm 11, the leaked oil can be used for lubrication thereof. Also,
If the bearing hole 10 in which the oil chamber 33 is provided is formed as a blind hole, the blind cover 32 can be omitted.

As described above, according to the present invention, an oil chamber facing the end face of the journal is formed in the bearing hole that supports the journal to which the gap elimination unit is connected, and this oil chamber is opened to the outside through the relief hole. Therefore, even if pressure oil leaks from the oil sump chamber of the clearance elimination unit into the bearing hole and flows into the oil chamber, the pressure of the pressure oil is immediately released to the outside through the relief hole, and therefore the pressure is reduced. In addition to preventing thrust loads from being applied to the rocker shaft due to oil, the oil in the oil chamber can keep the journal in a good lubricated state, and as a result, the rocker shaft can rotate smoothly. This makes it possible to obtain an accurate valve head clearance clearance effect.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a side view of a motorcycle having an engine to which the present invention is applied, FIG. 2 is a partially cutaway plan view of the main parts of the engine, and FIGS. 4 is a sectional view taken along the line - and - of FIG. 2, FIG. 5 is an enlarged sectional view taken along the line - 3 of FIG. 3, and FIG. 6 is a perspective view showing the valve operating mechanism of the exhaust valve. B ₁ , B ₂ ... Engine block, E ... Engine, M ... Valve mechanism, Vi, Ve ... Valve, Z ... Gap elimination unit, 1 ... Camshaft, 2i, 2e ...
Rocker shaft, 7...Journal, 8...Eccentric shaft, 1
0... Bearing hole, 11... Locker arm, 14...
Notch, 21... Oil reservoir chamber, 31... Oil hole, 33...
Oil chamber, 34... escape hole.

Claims (1)

[Claims] 1. An eccentric shaft is formed on the rocker shaft, which rotatably supports the journal in the bearing hole of the engine block, and is eccentric by a certain amount from the center of rotation of the shaft, and the rocker arm that transmits the valve opening force of the camshaft to the valve is moved from the eccentric shaft. The shaft is swingably supported, and a notch is provided on the outer peripheral surface of the journal, and in this notch, when the valve is opened, the eccentric shaft is rotated in a direction that eliminates the valve head gap, and when the valve is opened, the eccentric shaft is rotated. A hydraulic gap eliminating unit for preventing rotation is connected to the rocker shaft, and the gap eliminating unit is provided with an oil hole that communicates with an internal oil reservoir chamber and opens in the notch. A valve head gap eliminating device for a valve mechanism, characterized in that an oil chamber facing an end face of the journal is formed in the bearing hole, and the oil chamber is opened to the outside through a relief hole. Headspace elimination device.