JP2003065024A - Valve mechanism lubricating device of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lubricate a valve mechanism without resistance by feeding oil mist not containing an oil droplet. SOLUTION: In the valve mechanism lubricating device of engine, in which a head cover 36 is connected to an upper end of a cylinder head 8, the valve mechanism chamber 21b is demarcated between the cylinder head 8 and the head cover 36, a transfer means 61 for transferring oil mist in an oil tank 40, an oil recovering chamber 74 for recovering by sucking the oil stored in the valve mechanism chamber 21b, and a breather chamber 69 extracting blow-by gas from the valve mechanism chamber 21b are connected to the valve mechanism chamber 21b, an oil droplet separating chamber 73 for introducing the oil mist not containing the oil droplet into the valve mechanism chamber 21b by separating oil droplet from the oil mist fed from the transfer means 61 is provided between the transfer means 61 and the valve mechanism chamber 21b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a handheld four-cycle engine which is mainly used as a power source for a trimmer or other portable work machine, and more particularly, a cylinder head and a cylinder head having a head cover connected to the upper end thereof. An oil mist transfer means for defining a valve operating chamber accommodating the valve operating mechanism between the head covers and transferring the oil mist generated in the oil tank to the valve operating chamber,
The oil recovery chamber that sucks and collects the oil accumulated in the valve operating chamber and the breather chamber that takes out the blow-by gas from the valve operating chamber and discharges it to the outside are connected to the oil recovery chamber. The present invention relates to an improvement in an engine valve mechanism lubrication device, which is connected to an oil return passage for returning oil to an oil tank.

[0002]

2. Description of the Related Art A valve operating mechanism lubricator for such an engine is
For example, it is already known as disclosed in Japanese Patent Laid-Open No. 11-125107.

[0003]

In such a conventional engine valve mechanism lubrication device, the oil mist transfer means was directly connected to the valve chamber, so that the oil mist is generated in the valve chamber during transfer of the oil mist. The oil drops are also supplied, and these oil drops act as resistance to actuation of the valve mechanism and contribute to power loss.

The present invention has been made in view of these points, and an engine in which an oil mist containing no oil droplets is supplied to the valve operating chamber so that the valve operating mechanism can be lubricated without resistance. It is an object of the present invention to provide a valve operating mechanism lubrication device.

[0005]

In order to achieve the above object, the present invention provides a valve operating chamber for connecting a head cover to an upper end of a cylinder head and housing a valve operating mechanism between the cylinder head and the head cover. In addition to this, the oil mist transfer means for transferring the oil mist generated in the oil tank to the valve operating chamber, the oil recovery chamber for sucking and collecting the oil accumulated in the valve operating chamber, and the blow-by from the valve operating chamber. In the engine valve train lubrication system, the oil recovery chamber is connected to a breather chamber that takes out gas and discharges the gas to the outside, and the oil recovery chamber is connected to an oil return passage for returning the oil recovered in the chamber to the oil tank. Between the mist transfer means and the valve operating chamber, oil drops are separated from the oil mist sent from the oil mist transferring means, and the oil mist containing no oil drops is transferred to the valve operating chamber. A first feature in that a oil droplets separating chamber to guide.

The valve operating chamber and the oil mist transfer means are provided as a second valve operating chamber 21b in an embodiment of the present invention described later.
And one-way valve 61.

According to the first feature, since the oil drop separating chamber is provided between the oil mist transfer means and the valve operating chamber, the oil drops generated during the transfer of the oil mist are separated in the oil drop separating chamber, Oil mist that does not contain oil droplets is supplied to the valve operating chamber, so that the valve operating mechanism can be lubricated without resistance, which can contribute to a reduction in power loss.

In addition to the first feature of the present invention, a partition body which defines a breather chamber between the inner wall of the head cover and the ceiling surface of the head cover is attached, and the oil recovery chamber is integrated with this partition body. Secondly, the oil drop separation chamber is defined between the partition body and the cylinder head.
It is a feature of.

According to the second feature, the oil recovery chamber and the breather chamber can be provided in the head cover without dividing the ceiling wall of the head cover, and both the breather chamber and the oil recovery chamber are present in the head cover. Therefore, even if there is some oil leakage from both rooms,
The oil only returns to the valve operating chamber without any hindrance,
Oil-tightness inspection around both chambers is not required, and manufacturing costs can be reduced. Moreover, since the partition body is also used to form the oil droplet separation chamber, the structure can be simplified.

According to the second feature of the present invention, the third feature is that the oil droplet separating chamber is arranged between a pair of intake and exhaust rocker shafts of the valve train arranged in parallel with each other. To do.

According to the third feature, the relatively narrow space of the head cover can be efficiently used for forming the oil droplet separation chamber, and the enlargement of the head cover can be avoided.

Further, in addition to any one of the first to third features, the present invention communicates the oil droplet separating chamber with the oil return passage so that the oil droplets separated in the oil droplet separating chamber can be transferred to the oil tank. The fourth characteristic is that the material is refluxed.

According to the fourth feature, the oil droplets separated in the oil droplet separating chamber can be quickly returned to the oil tank to prevent the oil droplets from entering the valve operating chamber.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described based on the embodiments of the present invention shown in the accompanying drawings.

FIG. 1 is a perspective view showing an example of use of the handheld four-cycle engine of the present invention, FIG. 2 is a vertical sectional side view of the above-mentioned four-cycle engine, and FIG. 3 is a sectional view taken along line 3-3 of FIG. 2 is a sectional view taken along line 4-4 of FIG. 2, FIG. 5 is an enlarged sectional view of an essential part of FIG. 2, FIG. 6 is an exploded view of an essential part of FIG. 5, and FIG.
7 is a sectional view taken along line 7, FIG. 8 is a sectional view taken along line 8-8 in FIG. 4, and FIG.
9 is a sectional view taken along line 9-9, FIG. 10 is a sectional view taken along line 10-10 of FIG. 5, FIG. 11 is a sectional view taken along line 11-11 of FIG. 5, and FIG.
12 is a sectional view taken along line 12-12, FIG. 13 is a lubrication path diagram of the engine, FIG. 14 is an inverted state of the engine, a correspondence diagram with FIG. 4, and FIG. 15 is a lateral state of the engine, and FIG. FIG.

As shown in FIG. 1, the handheld four-cycle engine E is attached to its drive unit as a power source of a power trimmer T, for example. Since the power trimmer T is used with the cutter C oriented in various directions depending on its working state, the engine E is also greatly tilted or inverted each time, and its operating posture is not constant.

First, the structure of the outer periphery of the handheld four-cycle engine E will be described with reference to FIGS.

A carburetor 2 and an exhaust muffler 3 are attached to the front and rear of the engine body 1 of the handheld four-cycle engine E, and an air cleaner 4 is attached to the intake passage inlet of the carburetor 2. A fuel tank 5 made of synthetic resin is attached to the lower surface of the engine body 1. The crankshaft 13 has both ends projecting outward from both sides of the engine body 1 and the oil tank 40 adjacent to one side of the engine body 1, and a driven member 84 fixed to one end thereof.
A recoil starter 42 that can be transmitted and connected to the oil tank 40 is attached to the outer surface of the oil tank 40.

A cooling fan 43 which doubles as a flywheel is fixed to the other end of the crankshaft 13. A plurality of mounting bosses 46 (one of which is shown in FIG. 2) are formed on the outer side surface of the cooling fan 43, and a centrifugal shoe 47 is rotatably supported on each of the mounting bosses 46. To be done. The centrifugal shoe 47 constitutes a centrifugal clutch 48 together with a clutch drum 48 fixed to a drive shaft 50, which will be described later. When the rotational speed of the crankshaft 13 exceeds a predetermined value, the centrifugal shoe 47 will centrifuge itself. The force presses the inner peripheral wall of the clutch drum 48 to transmit the output torque of the crankshaft 13 to the drive shaft 50. The cooling fan 43 has a larger diameter than the centrifugal clutch 48.

An engine cover 51, which covers the engine body 1 and auxiliary equipment other than the fuel tank 40, is fixed in place on the engine body 1, and a cooling air intake 19 is provided between the engine cover 51 and the fuel tank 5. To be Therefore, by the rotation of the cooling fan 43, the outside air is taken in from the cooling air intake port 19 and used for cooling the various parts of the engine E.

A frusto-conical bearing holder 58, which is arranged coaxially with the crankshaft 6, is fixed to the engine cover 51. The bearing holder 58 supports a drive shaft 50 for rotating the cutter C via a bearing 59. To do.

Since the engine body 1 is placed between the oil tank 40 and the starter 42 on one side and the cooling fan 43 and the centrifugal clutch 49 on the other side, the left and right weight balance of the engine E is balanced. Is good, the center of gravity of the engine E can be brought closer to the center of the engine body 1, and the maneuverability of the engine E is improved.

Further, between the engine body 1 and the centrifugal shoe 47, a cooling fan 43 having a diameter larger than that of the centrifugal shoe 47 is provided.
Is fixed to the crankshaft 13, it is possible to prevent the engine E from becoming large due to the cooling fan 43.

Next, the engine body 1 and the oil tank 4
The structure of 0 will be described.

2 to 5, the engine body 1 is
The cylinder block 7 includes a crankcase 6 having a crank chamber 6a, a cylinder block 7 having one cylinder bore 7a, and a combustion chamber 8a and a cylinder head 8 having intake and exhaust ports 9 and 10 opening into the chamber 8. A large number of cooling fins 38 are formed on the outer circumference of the cylinder head 8.

Crankshaft 1 housed in the crank chamber 6a
3 is rotatably supported on the left and right side walls of the crankcase 6 via ball bearings 14 and 14 '. At that time, the ball bearing 14 on the left side has a seal,
An oil seal 17 is arranged adjacent to the outside of the ball bearing 14 'on the right side. A piston 15 fitted in the cylinder bore 7a is connected to the crankshaft 13 via a connecting rod 16 as in the conventional case.

An oil tank 40 adjacent to the outer side of the crankcase 6 is integrally provided on the left side wall of the crankcase 6, and the end of the crankshaft 13 on the side of the sealed ball bearing 14 penetrates the oil tank 40. Will be placed. The oil tank 40, which is penetrated by the crankshaft 13,
An oil seal 39 is attached to the outer wall of the.

On the ceiling wall of the oil tank 40, a belt guide cylinder 86 having a flat cross section, which vertically extends so as to penetrate the oil tank 40 and whose upper and lower ends are open, is integrally provided. The lower end of the belt guide cylinder 86 extends to the vicinity of the crankshaft 13 in the oil tank 40, and the upper end thereof is integrally connected to the cylinder head 8 so as to share the partition wall 85 with the cylinder head 8. It A series of annular seal beads 87 are formed around the upper ends of the cylinder head 8 and the belt guide cylinder 86, and the partition wall 85 projects above the seal beads 87.

On the other hand, as shown in FIGS. 6 and 10 to 12, an annular seal groove 88a corresponding to the seal bead 87 is formed on the lower end surface of the head cover 36, and the cover 3 is also formed.
On the inner surface of 6, a linear seal groove 88b is formed to connect both sides of the annular seal groove 88a. An annular packing 89a is attached to the annular seal groove 88a, and an annular packing is attached to the linear seal groove 88b. The linear packing 89b integrally formed with 89a is mounted. A seal bead 87 is provided on the annular packing 89a, and a linear packing 89b is provided.
The head cover 36 is connected to the cylinder head 8 with bolts 37 so that the partition walls 85 are pressed against each other.

The belt guide cylinder 86 and one half of the head cover 36 form the first valve chamber 21a, and the cylinder head 8 and the other half of the head cover 36 form the second valve chamber 21.
b is defined, and both valve operating chambers 21a and 21b are partitioned by the partition wall 85.

Referring again to FIGS. 2-5, the engine body 1
The oil tank 40 is a plane that passes through the axis of the crankshaft 13 and is orthogonal to the axis of the cylinder bore 7a, and is divided into an upper block Ba and a lower block Bb. That is, the upper block Ba is the upper half of the crankcase 6,
The cylinder block 7, the cylinder head 8, the upper half of the oil tank 40, and the belt guide cylinder 86 are integrally connected, and the lower block Bb includes the lower half of the crankcase 6 and the lower half of the oil tank 40. The upper and lower blocks Ba and Bb are individually cast, and after processing each part, a plurality of bolts 1
2 (see FIG. 4).

The cylinder head 8 is provided with an intake valve 18i and an exhaust valve 18e for opening and closing the intake port 9 and the exhaust port 10, respectively, in parallel with the axis of the cylinder bore 7a, and the spark plug 20 has its electrode connected to the combustion chamber 8a. It is screwed close to the center of the.

Next, the intake valve 18i and the exhaust valve 18e.
The valve mechanism 22 for opening and closing the valve will be described with reference to FIGS.

The valve mechanism 22 includes a timing transmission device 22a arranged from the oil tank 40 to the first valve chamber 21a, and the first valve chamber 21a to the second valve chamber 21b.
It is composed of a cam device 22b which is arranged over.

The timing transmission 22a includes an oil tank 40
A drive pulley 23 fixed to the inner crankshaft 13, a driven pulley 24 rotatably supported above the belt guide cylinder 86, and a timing belt 25 wound between the drive and driven pulleys 23, 24. A cam 26, which is a part of the cam device 22b, is integrally coupled to the end face of the driven pulley 24 on the partition wall 85 side. The drive and driven pulleys 23 and 24 are toothed, and the drive pulley 23
Drives the driven pulley 24 via the belt 25 at a speed reduction ratio of 1/2.

On the outer wall of the belt guide cylinder 86, there is integrally formed a support wall 27 which stands up inside the annular seal bead 87 and abuts or comes close to the inner surface of the head cover 36. Both ends of the support shaft 29 are rotatably supported by the through hole 28a provided and the bottomed hole 28b provided in the partition wall 85, and the driven pulley 24 and the cam 26 are rotatably supported at an intermediate portion of the support shaft 29. To be done. The support shaft 29 has a through hole 28 before the head cover 36 is attached.
It is inserted from a into the driven pulley 24 and the shaft hole 35 of the cam 26, and the hole 28b with a bottom. After the insertion, when the head cover 36 is joined to the cylinder head 8 and the belt guide cylinder 86, the inner surface of the head cover 36 becomes It opposes the outer end of the support shaft 29 so as to prevent it from coming off.

The partition wall 85 has a second wall from the cylinder head 8.
One end of each of a pair of bearing bosses 30i, 30e standing upright on the valve operating chamber 21b side and extending parallel to the support shaft 29 is integrally coupled, and these bearing bosses 30i, 30e connect the intake rocker shaft 31i and the intake rocker shaft 31i of the cam device 22b. The exhaust rocker shafts 31e are rotatably supported. That is, the cam device 22b
Is an intake air that is fixed to the cam 26, the intake rocker shaft 31i and the exhaust rocker shaft 31e, and one end of each of the rocker shafts 31i and 31e in the first valve chamber 21a so that the tip of the cam 26 slides against the lower surface of the cam 26. The intake follower 22i and the exhaust cam follower 22e, and the intake rocker arm 33i that is fixed to the other ends of the intake and exhaust rocker shafts 31i and 31e in the second valve chamber 21b and has their tips abutted against the upper ends of the intake valve 18i and the exhaust valve 18e. And exhaust rocker arm 3
3e, and an intake spring 34i and an exhaust spring 34e that are attached to the intake valve 18i and the exhaust valve 18e and urge them in the valve closing direction.

When the crankshaft 13 rotates, the drive pulley 23 rotating with it rotates the driven pulley 24 and the cam 26 via the belt 25, and the cam 26 causes the intake and exhaust cam followers 32i, 32e to move in time. The rocker shafts 31i, 31
Since it is transmitted to the intake and exhaust rocker arms 33i and 33e via e to swing them, the intake and exhaust valves 18i and 34e cooperate with the intake and exhaust springs 34i and 34e.
i, 18e can be opened and closed at appropriate times.

In the timing transmission 22a, the driven pulley 24 and the cam 26 are rotatably supported by the support shaft 29, and the support shaft 29 is also rotatably supported by both side walls of the first valve chamber 21a. During the rotation of the driven pulley 24 and the cam 26, the support shaft 29 is also dragged due to friction and the rotation speed difference between the driven pulley 24 and the cam 26 and the support shaft 29 decreases, and It is possible to reduce wear and contribute to improved durability.

Next, the lubricating system of the engine E will be described with reference to FIGS.

In FIGS. 4 and 5, the oil tank 40
A predetermined amount of lubricating oil O injected from the oil supply port 40a is stored in the. In this oil tank 40,
A pair of oil slinger 56a, 56b arranged in the axial direction with the drive pulley 23 interposed therebetween is fixed to the crankshaft 13 by press fitting or the like. These oil slinger 56a, 56
b are diametrically opposed to each other, and are bent so that their tips are separated from each other in the axial direction, and when driven by the crankshaft 13, the oil slinger 56a, 56a, At least one of 56b stirs and scatters the stored oil O in the oil tank 40 to generate an oil mist. At this time, the generated oil droplets are discharged from the first valve operating chamber 21.
The timing transmission device 22 exposed from the inside of the oil tank 40
The timing transmission 22a is directly lubricated by being sprinkled on a part of "a" or entering the first valve chamber 21a, and this is one lubrication system.

Another lubrication system is, as shown in FIGS. 3 to 5 and 13, a through hole 55 provided in the crankshaft 13 for communicating the inside of the oil tank 40 and the crank chamber 6a. , An oil feed conduit 60 connected to the lower portion of the crank chamber 6a, and oil drops separated from the oil mist sent by the oil feed conduit 60 to guide an oil mist containing no oil drops to the second valve operating chamber 21b. Oil drop separation chamber 73
An oil recovery chamber 74 provided in the cylinder head 8 to suck up oil droplets accumulated in the second valve operating chamber 21b, and to communicate the oil recovery chamber 74 with the oil tank 40 via the first valve operating chamber 21a. An oil return passage 78 formed between the cylinder head 8 and the oil tank 40, and a one-way valve installed in the lower part of the crank chamber 6a and allowing the flow of oil mist in only one direction from the crank chamber 6a to the oil feed conduit 60. And 61.

The opening end 55a of the through hole 55 into the oil tank 40 is always exposed above the liquid surface of the oil O in the oil tank 40, regardless of the posture of the engine E. It is arranged in the center of 40 or in the vicinity thereof. The drive pulley 23 to which the crankshaft 13 is fixed and one oil slinger 56a are
The open end 55a is disposed so as not to block a.

The one-way valve 61 (see FIG. 3) is composed of a reed valve in the illustrated example, and is closed when the crank chamber 6a has a negative pressure due to the reciprocating motion of the piston 15 and has a positive pressure. It is supposed to open when.

The lower end of the oil feed conduit 60 has a lower connecting pipe 62a (see FIG. 3) protruding from the outer surface of the crankcase 6.
(Refer to FIG. 4 and FIG. 8), and the upper end of the upper connection pipe 62b is projected on the outer surface of the cylinder head 8 (see FIGS. 4 and 8).
Are fitted and connected respectively. Upper connecting pipe 62b
The inside of is communicated with the oil drop separation chamber 73 via the communication passage 63 (see FIGS. 8 and 9) of the cylinder head 8.

The oil drop separating chamber 73 is provided with the bearing bosses 30i,
30e and both bearing bosses 30 while facing the partition wall 85.
The oil droplet separation chamber 7 is defined by a small partition 92 integrally formed with the cylinder head 8 so as to connect between the i and 30e.
The communication hole 63 is opened at one corner of the No. 3, and the small partition wall 92 is provided with a cutout-shaped outlet 92a for communicating the oil droplet separation chamber 73 with the second valve operating chamber 21b.

As shown in FIGS. 5 and 10 to 12, a partition body 65 is provided on the head cover 36. The partition body 65 includes an upper partition plate 65a made of a synthetic resin that defines a breather chamber 69 between the partition body 65 and the ceiling surface of the head cover 36.
The lower partition plate 65b made of synthetic resin is joined to the lower surface of the upper partition plate 65a by welding or adhesion and defines a flat oil recovery chamber 74 between the lower partition plate 65b and the upper wall.
When the partition body 65 is attached to the head cover 36, the peripheral portion of the upper partition plate 65a is brought into contact with the stepped portion of the inner peripheral surface of the head cover 36, and the upper partition plate 6
The clip 67 is locked to the projection 66 of the head cover 36 penetrating the 5a and presses the upper partition plate 65a.

The lower partition plate 65b is used for the oil drop separation chamber 7
3, which is also used to close the open upper surface of the opening 3, the lower surface of which has a U-shaped positioning wall 93 which fits the inner surface of the oil drop separation chamber 73 on the partition wall 85 side, and a small partition wall of the oil drop separation chamber 73. 9
The linear positioning wall 94 that fits to the inner surface on the second side, and the effective opening area of the outlet 92a, that is, between the oil droplet separating chamber 73 and the second valve operating chamber 21b, with the linear partitioning wall 94 sandwiching the small partition wall 92. A small piece 95 that defines the opening and a maze wall 96 that rushes into the oil drop separation chamber 73 to promote oil drop separation.
And are projected.

On the other hand, the breather chamber 69 is connected to the second valve operating chamber 2 through a communication hole 68 provided in the upper partition plate 65a.
1b, and on the other hand, communicates with the inside of the air cleaner 4 through the breather pipe 70. This breather room 69
Is for separating gas and liquid of mixed oil and blow-by gas, and a labyrinth wall 72 for promoting the gas-liquid separation is provided on the inner surface of the ceiling wall of the head cover 36.
Further, the upper partition plate 65a is provided with an eave 68a which covers the upper side of the communication hole 68 and which suppresses the entry of oil droplets from the second valve operating chamber 21b into the breather chamber 69 as much as possible.

On the lower partition plate 65b, a plurality of (two in the illustrated example) suction pipes 75 that communicate with the oil recovery chamber 74 at locations separated from each other are integrally provided. Each of the suction pipes 75 has its tip extending to the vicinity of the bottom surface of the second valve operating chamber 21b, and each tip opening is an orifice 75a.

Further, a plurality (three in the illustrated example) of suction pipes 76 that communicate with the oil recovery chamber 74 at locations separated from each other are also integrally provided on the upper partition plate 65b so as to project. Each of the suction pipes 76 has its tip extending to the vicinity of the ceiling surface of the breather chamber 69, and the tip end opening portion thereof serves as an orifice 76a.

Further, the lower partition plate 65b and the upper partition plate 65a are respectively provided with a plurality of orifices 80 and 83 for communicating the second valve operating chamber 21b and the breather chamber 69 with the oil recovery chamber 74. Both partition plates 6
A plurality of notch-shaped orifices 97 for communicating the second valve operating chamber 21b with the oil recovery chamber 74 also between the joint surfaces of 5a and 65b.
(FIG. 11) is provided.

An oil recovery chamber 74 is provided in the lower partition 65b.
One return pipe 81 opening to the above is integrally provided. The tip end of the return pipe 81 penetrates the oil drop separation chamber 73, is fitted into the inlet 78a of the oil return passage 78 provided in the cylinder head 8 via the grommet 82, and is collected in the oil recovery chamber 74. The oil is guided to the oil return passage 78.

The lower partition 65b is further provided with an orifice 9 which connects the oil drop separation chamber 73 and the oil recovery chamber 74.
1 is drilled.

The return pipe 81 has an oil drop separation chamber 73.
An orifice-like return hole 90 communicating with the lower part of the oil is bored so that the oil collected in the oil drop separation chamber 73 also flows out to the oil return passage 78.

Since the breather chamber 69 for explaining the action of the lubricating system is communicated with the air cleaner 4 through the breather pipe 70, the pressure in the breather chamber 69 is kept substantially at atmospheric pressure even when the engine E is operating. The second valve operating chamber 21b, which is maintained and communicates with the breather chamber 69 through the communication hole 68 with low flow resistance, has substantially the same pressure as the breather chamber 69, and the second valve chamber 21b is connected through the outlet 92a with low flow resistance. The oil drop separation chamber 73 communicating with the second valve operating chamber 21b is the second valve operating chamber 21b.
Is almost the same pressure.

During operation of the engine E, the crank chamber 6a is
Since only the positive pressure component of the pressure pulsation generated by the elevation of the piston 15 is discharged from the one-way valve 61 to the oil feed conduit 60, the crank chamber 6a is in a negative pressure state on average, and the positive pressure is applied to the second valve chamber. 21b receives. Since the negative pressure in the crank chamber 6a is transmitted to the oil tank 40 through the through hole 55 of the crankshaft 13 and further to the oil recovery chamber 74 through the oil return passage 78, the oil recovery chamber 74 is
The valve operating chamber 21b, the oil droplet separating chamber 73, and the breather chamber 69 are at a lower pressure than the oil tank 40 and the first valve operating chamber 21a are at a lower pressure than the oil recovery chamber 74.

Therefore, as shown in FIG. 13, the pressure in the crank chamber 6a is Pc and the pressure in the oil tank 40 is Pc.
o, the pressure of the first valve operating chamber 21a is Pva, the pressure of the second valve operating chamber 21a
The pressure of b is Pvb, the pressure of the oil drop separation chamber 73 is Py, the pressure of the oil recovery chamber 74 is Ps, and the pressure of the breather chamber 69 is Ps.
If b, the magnitude relation can be expressed by the following equation.

Pb = Pvb = Py>Ps> Pva = Po> Pc As a result, the pressure in the breather chamber 69 and the second valve operating chamber 21b is transferred to the oil recovery chamber 74 through the suction pipes 75 and 76 and the orifices 80 and 83, and The pressure in the oil drop separation chamber 73 is transferred to the return pipe 81 and the oil recovery chamber 74 through the return hole 90 and the orifice 91, and the pressure is passed through the oil return passage 78 to the oil tank 40 and the crank chamber 6a.
Move on to.

During operation of the engine E, in the oil tank 40, the oil slinger 56a, 56b rotated by the crankshaft 13 agitates and scatters the lubricating oil O to generate an oil mist. The oil splash generated at that time is part of the timing transmission 22a exposed from the belt guide cylinder 86 into the oil tank 40, that is, the drive pulley 2.
3 and a part of the timing belt 25, or it enters the first valve operating chamber 21a, and the timing transmission 22a
The direct lubrication is as described above.

The oil mist generated in the oil tank 40 is sucked into the crank chamber 6a through the through hole 55 of the crankshaft 13 in accordance with the pressure flow described above, and lubricates the periphery of the piston 15 of the crankshaft 13. Then the piston 15
When the crank chamber 6a becomes a positive pressure due to the downward movement of the oil mist, the one-way valve 61 is opened to move the oil mist to the oil feed conduit 6
0 and the communication passage 63 are ascended and supplied to the oil drop separation chamber 73. At this time, the expansion of the oil mist and the collision with the maze wall 96 separate the oil droplets in the oil mist. The oil mist containing no oil droplets is discharged from the outlet 92a.
With this, the flow rate is appropriately adjusted and supplied to the second valve operating chamber 21b, and it is possible to effectively lubricate each part of the cam device 22b in the chamber 21b, that is, the intake and exhaust rocker arms 33i, 33e. Thus, the cam device 2 by oil drops
It is possible to avoid the operation resistance of 2b and reduce the power loss.

The oil droplets separated in the oil droplet separating chamber 73 and accumulated at the bottom of the chamber 73 are sucked out to the return pipe 81 through the return hole 90, pass through the oil return passage 78, and pass through the oil tank 40.
Reflux to.

When the oil mist in the second valve operating chamber 21b and the blow-by gas contained in the oil mist move to the breather chamber 69 through the communication hole 68, the expansion action and the maze wall 7 at that time are transferred.
The blow-by gas is separated into gas and liquid by the collision action with 2, and is sucked into the engine E through the breather pipe 70 and the air cleaner 4 in order during the intake stroke of the engine E.

The oil droplets liquefied and accumulated in the breather chamber 69 are accumulated on the upper surface of the upper partition plate 65a or flow down through the communication hole 68 in the upright state of the engine E and the second valve operating chamber 21
Since it collects on the bottom surface of b, it is sucked up to the oil recovery chamber 74 by the orifice 80 and the suction pipe 75 waiting at those places. Further, when the engine E is upside down, the oil droplets may be collected on the ceiling surface of the head cover 36 or the lower partition 65b.
Since it collects on the lower surface of the oil collecting chamber 74, it is sucked up into the oil recovery chamber 74 by the suction pipe 76 and the orifices 83 and 97 which stand by there. On the other hand, in the oil droplet separating chamber 73, the oil droplets separated from the oil mist are collected on the ceiling surface of the chamber 73, and the oil droplets are collected in the oil recovery chamber 74 by the orifice 91 opening on the ceiling surface. It is sucked up.

The oil thus sucked into the oil recovery chamber 74 flows back from the return pipe 81 to the oil tank 40 through the oil return passage 78. In this case, if the oil return passage 78 is communicated with the oil tank 40 through the second valve operating chamber 21b as in the illustrated example, the oil return passage 78
It is convenient that the oil that comes out of this way sprinkles on the timing transmission 22a and contributes to the lubrication thereof.

The breather chamber 69 is defined between the ceiling surface of the head cover 36 and the upper partition plate 65a attached to the inner wall of the head cover 36, and the oil recovery chamber 74 includes the upper partition plate 65a. Since it is defined between the lower partition plate 65b joined to it,
The oil recovery chamber 74 and the breather chamber 69 can be provided in the head cover 36 without dividing the ceiling wall of the head cover 36. Moreover, since the breather chamber 69 and the oil recovery chamber 74 both exist in the head cover 36, even if some oil leaks from both chambers 69 and 74, the oil returns to the second valve operating chamber 21b. This does not cause any trouble, and the oil tightness inspection around the both chambers 69 and 74 is not necessary, and the manufacturing cost can be reduced.

Moreover, since the oil recovery chamber 74 is formed at the same time as the upper partition plate 65a and the lower partition plate 65b are joined together, the formation thereof can be performed easily.

Further, since the oil suction pipes 75 and 76 are integrally formed with the lower partition plate 65b and the upper partition plate 65a, respectively, the oil suction pipes 75 and 76 can be easily formed.

The oil drop separation chamber 73 has a bearing boss 30i, which supports a pair of intake and exhaust rocker shafts 31i and 31e.
Since it is formed between 30e, the relatively narrow space of the head cover 36 can be efficiently used for forming the oil droplet separation chamber 73,
It is possible to avoid enlargement of the head cover 36. In addition, the open upper surface of the oil drop separation chamber 73 has a lower partition plate 65.
Since it is closed by b, no special member for closing is required, and the structure can be simplified.

On the other hand, in the oil tank 40, the engine E
As shown in FIG. 14, when the tank 40 is turned upside down, the stored oil O is on the ceiling side of the tank 40, that is, the first valve operating chamber 21a.
The oil tank 40 of the first valve operating chamber 21a.
The inward opening end is set by the belt guide cylinder 86 so as to occupy a position higher than the liquid surface of the stored oil O. Therefore, the stored oil O is not allowed to flow into the second valve chamber 21b, It is possible to prevent excessive oiling of the timing transmission 22a, secure a predetermined amount of oil in the oil tank 40, and continue the generation of oil mist by the oil slinger 56a, 56b.

As shown in FIG. 15, when the engine E is laid down sideways, the stored oil O is stored in the tank 4
Although it moves to the side surface side of 0, the opening end of the first valve operating chamber 21a into the oil tank 40 is
It is set so as to occupy a position higher than the liquid level of the stored oil O. Therefore, in this case as well, the inflow of the stored oil O into the second valve chamber 21b is not allowed, and excessive oil supply of the timing transmission device 22a is prevented. Oil tank 40
Secure a predetermined amount of oil in the oil slinger 56
It is possible to continue the generation of oil mist by a and 56b.

Thus, the lubrication system of the valve mechanism 22 uses the scattered oil in the oil tank 40 and the time transmission device 22a and the cam device 2 in the oil tank 40 and the first valve chamber 21a.
Since it is divided into two systems, a system that lubricates a part of 2b and a system that lubricates the rest of the cam device 22b in the second valve chamber 21b by the oil mist transferred to the second valve chamber 21b. Since the load on each lubrication system is reduced, the entire valve mechanism 22 can be evenly lubricated. Moreover, by using oil splashes and oil mist,
It is possible to reliably lubricate each part of the engine regardless of the operating posture of the engine.

The oil misted in the oil tank 40 is supplied to the one-way valve 61 with the pressure pulsation of the crank chamber 6a.
Since the unidirectional transfer function is used for circulation, a dedicated oil pump for circulating the oil mist is unnecessary, and the structure can be simplified.

Further, not only the oil tank 40 but also the oil feed conduit 60 connecting the crank chamber 6a and the second valve operating chamber 21b is arranged outside the engine body 1, so that the engine body 1 can be made thin and compact. Can be greatly contributed to the weight reduction of the engine E. In particular,
The externally arranged oil feed conduit 60 is not easily affected by heat from the engine body 1 and easily radiates heat, so that cooling of the oil mist passing therethrough can be promoted.

Further, since the oil tank 40 is arranged on the outside of the engine body 1, the overall height of the engine E can be greatly reduced, and a part of the timing transmission 22a is housed in the oil tank 40. Therefore, the increase in the width of the engine E can be suppressed as much as possible, and the size can be reduced.

The present invention is not limited to the above embodiments, and various design changes can be made without departing from the scope of the invention. For example, oil suction pipes 75, 7
The number of 6 and the suction orifices 80 and 83 and the installation locations are freely selected. Further, instead of the one-way valve 61, the oil feed conduit 6 is interlocked with the crankshaft 13.
It is also possible to provide a rotary valve that operates so that 0 is conducted when the piston 15 descends and is shut off when the piston 15 rises.

[0077]

As described above, according to the first feature of the present invention, the head cover is connected to the upper end of the cylinder head,
A valve operating chamber for accommodating the valve operating mechanism is defined between the cylinder head and the head cover, and an oil mist transfer means for transferring the oil mist generated in the oil tank to the valve operating chamber and the valve operating chamber collecting the oil mist. The oil recovery chamber that sucks and collects the collected oil and the breather chamber that extracts the blow-by gas from the valve operating chamber and discharges it to the outside are connected, and the oil recovered in the chamber is returned to the oil tank. In an engine valve mechanism lubrication device with an oil return passage connected, an oil drop is separated from the oil mist sent from the oil mist transfer means between the oil mist transfer means and the valve operating chamber to contain the oil drop. Since the oil drop separation chamber that guides the oil mist that does not exist to the valve drive chamber is provided, the oil drop generated during the transfer of the oil mist is separated in the oil drop separation chamber, and the valve drive chamber contains the oil drops. There oil mist can be supplied to the valve chamber, thus lubricated without resistance the valve operating mechanism,
Power loss can be reduced.

According to the second feature of the present invention, in addition to the first feature, a partition body which defines a breather chamber between the inner wall of the head cover and the ceiling surface of the head cover is attached, Since the oil recovery chamber is integrally formed in the body and the oil drop separation chamber is defined between the partition body and the cylinder head, the head cover is provided with the oil recovery chamber and the breather chamber without dividing the ceiling wall of the head cover. Since the breather chamber and the oil recovery chamber both exist in the head cover, even if there is some oil leakage from both chambers, the oil only returns to the valve operating chamber without any hindrance. ， Oil-tightness inspection around both chambers is not required, and the manufacturing cost can be reduced. Moreover, since the partition body is also used to form the oil droplet separation chamber, the structure can be simplified.

Further, according to the third feature of the present invention, the second
According to the feature, since the oil drop separation chamber is arranged between the pair of intake and exhaust rocker shafts arranged in parallel in the valve mechanism, the relatively narrow space of the head cover is used for forming the oil drop separation chamber. It can be used efficiently and avoids the enlargement of the head cover.

Furthermore, according to the fourth feature of the present invention,
In addition to any of the first to third characteristics, the oil drop separation chamber is connected to the oil return passage so that the oil drops separated in the oil drop separation chamber are returned to the oil tank. The oil droplets separated in the separation chamber can be quickly returned to the oil tank to prevent the oil droplets from entering the valve operating chamber.

[Brief description of drawings]

FIG. 1 is a perspective view showing a usage example of a four-cycle engine of the present invention.

FIG. 2 is a vertical sectional side view of the four-cycle engine.

3 is a sectional view taken along line 3-3 of FIG.

4 is a sectional view taken along line 4-4 of FIG.

5 is an enlarged cross-sectional view of the main part of FIG.

FIG. 6 is an exploded view of a main part of FIG.

7 is a sectional view taken along line 7-7 of FIG.

8 is a sectional view taken along line 8-8 of FIG.

9 is a sectional view taken along line 9-9 of FIG.

10 is a sectional view taken along line 10-10 of FIG.

11 is a sectional view taken along line 11-11 of FIG.

12 is a sectional view taken along line 12-12 of FIG.

FIG. 13 is a lubrication path diagram of the engine.

FIG. 14 is a view corresponding to FIG. 4, showing an inverted state of the engine.

FIG. 15 is a view corresponding to FIG. 4, showing a state in which the engine is laid sideways.

[Explanation of symbols]

E ... four-cycle engine 8 ... Cylinder head 21b ... Valve operating chamber (second operating chamber) 22 ... Valve mechanism 31i, 31e ... Rocker shaft 36 ... Head cover 61 ... Oil mist transfer means (one-way valve) 65 ... Partition 69 .. Breather room 73 ... Oil drop separation chamber 74 ... Oil collection room 78: Oil return passage

Continued front page    F term (reference) 3G013 AA05 AB03 BA04 BB12 BC11                       BD13 BD22 CA01                 3G015 BD11 BD24 BE05 BE13 BE15                       BF05 CA04 CA05 CA06 DA02                       EA26

Claims (4)

[Claims] 1. A head cover (36) is connected to an upper end of a cylinder head (8) to form the cylinder head (8).
A valve operating chamber (21b) accommodating the valve operating mechanism (22) is defined between the head cover (36) and the oil mist generated in the oil tank (40) is transferred to the valve operating chamber (21b). Means for transferring oil mist (61),
An oil recovery chamber (74) for sucking and recovering the oil accumulated in the valve operating chamber (21b), and a breather chamber (6) for extracting blow-by gas from the valve operating chamber (21b) and discharging it to the outside.
9) and the oil recovery chamber (74) is connected to the chamber (7
The oil mist transfer means (6) in the engine valve mechanism lubrication device, to which the oil return passage (78) for returning the oil collected in (4) to the oil tank (40) is connected.
1) and the valve operating chamber (21b) are separated from the oil mist sent from the oil mist transfer means (61) to guide the oil mist containing no oil droplet to the valve operating chamber (21b). An engine valve mechanism lubrication device, characterized in that an oil drop separation chamber (73) is provided. 2. The breather chamber (69) according to claim 1, wherein the breather chamber (69) is provided between the inner wall of the head cover (36) and the ceiling surface of the head cover (36).
A partition body (65) that defines the oil drop separation chamber is formed between the partition body (65) and the cylinder head (8) while the oil recovery chamber (74) is integrally formed on the partition body (65). An engine valve mechanism lubrication device characterized in that (73) is defined. 3. The engine valve mechanism lubricating device according to claim 2, wherein the oil drop separation chamber (73) is provided with a valve mechanism (2).
2) A valve operating mechanism lubricating device for an engine, characterized in that it is arranged between a pair of intake and exhaust rocker shafts (31i, 31e) arranged in parallel with each other. 4. The engine valve mechanism lubricating device according to claim 1, wherein the oil drop separation chamber (73) is communicated with the oil return passage (78), and the oil drop separation chamber (73) is connected. )
An engine valve mechanism lubrication device, characterized in that the oil droplets separated in (3) are returned to the oil tank (40).