JP2000257412A - Lubrication structure of valve drive portion for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify structure, improve design flexibility in forming a lubrication outlet, make small cylinder head surroundings, and commonize a function member. SOLUTION: A chamber is formed on a ceiling portion inside a cylinder head cover 22. A lubricating passage A, which supplies oil into a valve driving portion 24 and a breather which separates lubricating oil from blowby gas are defined inside the chamber, respectively. The chamber is defined by an internal cover 23. The internal cover 23 is located within the cylinder head cover 22, so as to cover the inside ceiling portion of the cylinder head cover 22 and to widely cover the valve drive portion 24 of an internal combustion engine 1 with a cylinder 2 thereof standing up.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating structure for a valve operating portion of an internal combustion engine, and more particularly to improving the degree of freedom in forming a refueling discharge port, miniaturizing a cylinder head, and sharing a functional member. The present invention relates to a lubrication structure for a valve drive unit of an internal combustion engine.

[0002]

2. Description of the Related Art A conventional lubricating structure for a valve operating portion of an internal combustion engine is disclosed in Japanese Patent Publication No. Hei 6-23529.
As described in Japanese Patent Application Laid-Open Publication No. H10-107, the oil supply nozzle is made to face the valve operating portion to supply the oil, so that the arrangement of the oil supply pipe is complicated. In addition, a breather device for separating the lubricating oil having an increased oil supply amount from the blow-by gas has also become large in size, and further downsizing has been demanded.

[0003] The invention of the present application solves the above-mentioned problems of a conventional lubrication structure for a valve operating portion of an internal combustion engine,
Provided is a lubrication structure for a valve drive section of an internal combustion engine, which simplifies the lubrication structure, improves the degree of freedom in forming the lubrication discharge port, particularly in the lubrication structure, reduces the size around the cylinder head, and enables the sharing of functional members. The task is to

[0004]

SUMMARY OF THE INVENTION The present invention relates to a lubrication structure for a valve operating portion of an internal combustion engine which solves the above-mentioned problems.
A chamber is formed in a ceiling portion in the cylinder head cover, and an oil supply passage for supplying oil to the valve drive unit and a breather passage for separating lubricating oil from the blow-by gas are formed on the same plane. A lubricating structure for a valve operating portion of an internal combustion engine.

According to the first aspect of the present invention, an oil supply passage for supplying oil to a valve drive unit is provided in a chamber formed in a ceiling portion of a cylinder head cover, and a lubricating oil is provided. And a breather passage separating the blower gas from the blow-by gas are respectively formed on the same plane.

As a result, a special lubrication pipe for lubricating the valve drive unit is not required, and the lubrication structure is simplified since the lubrication pipe is easily routed.

In addition, since the oil supply passage can be formed relatively freely in the chamber formed on the ceiling in the cylinder head cover, the oil supply discharge port (oil supply point) is formed particularly in the lubrication structure of the valve drive unit. Degree of freedom can be improved.

[0008] Further, this makes it possible to optimally lubricate a wide variety of lubricating points in the valve drive unit, thereby improving lubrication efficiency and reducing the amount of lubrication. Further, the durability of the valve drive unit can be improved.

In addition, the breather passage for separating the lubricating oil from the blow-by gas can be easily formed into various shapes, so that it can be formed into an optimum maze structure.
Breather performance can be improved.

[0010] Further, since an oil supply passage having a lubricating oil supply function and a breather passage having a breather function can be defined in a room formed in a ceiling portion of the cylinder head cover, the functional members can be shared. be able to. In addition, the size around the cylinder head can be reduced.

According to a second aspect of the present invention, the chamber is defined by an inner cover, which covers a ceiling portion in the cylinder head cover and a cylinder. Is disposed in the cylinder head cover so as to widely cover the valve operating portion of the standing internal combustion engine.

As a result, it is possible to extremely easily form a chamber in the ceiling portion in the cylinder head cover, and to easily form a large chamber, and to provide a degree of freedom in forming a lubrication discharge port in the lubrication structure of the valve drive unit, particularly, the oil supply discharge port. Can be further improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention described in claims 1 and 2 of the present application shown in FIGS. 1 to 6 will be described below. FIG. 1 is a partial vertical cross-sectional view of an internal combustion engine to which a lubrication structure for a valve train drive unit according to the present embodiment is applied, and FIG. 2 is a schematic right side view of a power unit including the internal combustion engine of FIG. FIG. 3 is a vertical sectional view taken along line III-III of FIG.
2 is a partially enlarged view of FIG. 2, FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3, FIG. 5 is a rear view of a cover that covers a timing cam chamber of the internal combustion engine of FIG. 1, and FIG. FIG. 5 is a plan view of a set plate for setting an oil pump used in the internal combustion engine of FIG.

Referring to FIGS. 1 and 2, an internal combustion engine 1 to which a lubrication structure of a valve train driving section according to the present embodiment is applied.
An overhead valve (OHV) type internal combustion engine comprising a power transmission device 50
To form a power unit 0, and is used, for example, as a prime mover of an auxiliary power vehicle with a pedal.

When the power unit 0 is mounted on an auxiliary power vehicle with a pedal, the power unit case 51
Brackets 52 erected at two places, an upper front side and a rear side, are bolted to a vehicle body frame (not shown), and the power unit 0 is fixed to the vehicle body of the auxiliary power vehicle with pedals. Reference numeral 53 denotes a pedal shaft, 54 denotes a cell motor, and 55 denotes an oil pan formed on the bottom of the crankcase 6.

The internal combustion engine 1 is, as shown in FIG.
A piston 3 reciprocating in the cylinder (cylinder) 2 is connected to a crankshaft 5 by a connecting rod 4, and the reciprocating motion of the piston 3 is converted into a rotational motion of the crankshaft 5.

The crankshaft 5 is supported and supported by ball bearings 7 at two locations on both ends thereof on semicircular bearings formed on respective mating surfaces of a vertically divided crankcase 6. ing. The crankcase 6
The power unit case 51 constitutes a case portion on the internal combustion engine 1 side.

Although not shown in detail, a rotor of an alternator, a clutch, a driven gear 41 for starting, and the like are mounted on the left end side of the crankshaft 5 in FIG. 5, the inner end of the oil pump 8 is fitted to the right end.

The oil pump 8 has a concave portion 11 (see FIGS. 1 and 5) formed on the back surface of the cover 10 which closes an opening 47 (see FIG. 2) of the timing cam chamber 9 provided on the side of the cylinder 2. And is covered with a set plate 12 (see FIGS. 1 and 6) and held in the recess 11.

FIGS. 5 and 6 show a single unit of the cover 10 and the set plate 12, respectively. The cover 10 is turned upside down from the state shown in the figure and is applied to the opening 47 of the timing cam chamber 9.

In FIG. 1, the lower part of the cylinder 2 and the crankcase 6 are formed by a cover shown in FIG.
Since it is cut along the direction of 10 cutting lines II,
It is depicted as being unfolded long, so the cover 10 shown in FIG. 1 is also shown unfolded longer than the cover 10 shown in FIG.

The timing cam chamber 9 accommodates a push rod 14, which is a component of the valve operating mechanism 13, and a timing cam mechanism 15 for moving the push rod 14 up and down.

The timing cam mechanism 15 includes a cam gear 16, which is driven by the crankshaft 5 via a gear. Then, the swing member 17 is swung.
The oscillating member 17 supports the lower ends of the two push rods 14 in the recesses at both oscillating blade ends symmetrically about the oscillating shaft 17a so as to be able to push up (FIG. 2). reference).

The rotating shaft 16a of the cam gear 16 and the swing member 17
Both ends of the swing shaft 17a are supported by bearing holes formed in the outer wall surface of the cylinder 2 and bearing holes formed in the back surface of the cover 10, respectively.

The lubricating oil stored in the oil pan 55 formed at the bottom of the crankcase 6 is sucked into the oil pump 8 through the oil passages 18 and 19, and flows through the oil pump 8 as indicated by an arrow E (intake side). , F (discharge side), and from the oil pump 8, an oil passage 46 formed on the side wall of the timing cam chamber 9 (see FIG. 2) and an oil passage 20 formed on the back surface of the cover 10 (see FIG. 2). 5), timing cam chamber 9
Flows sequentially through an oil passage 21 (see FIGS. 2 and 3) formed on the side wall of the cylinder head 40 and the cylinder head cover 22.
The lubricating oil is sent from the mating surface portion to the valve driving unit 24 in a portion centered on the rocker arm 25 in the inner cover 23 described later.

From the oil pump 8, as shown in FIG. 1, an oil passage 43 formed in the crankshaft 5, an oil passage 45 formed in the crankpin 44, and an oil passage formed in the connecting rod 4. (Not shown)
The lubricating oil is sent to the bearing portion of the crankshaft 5, the sliding portion between the connecting rod 4 and the crankshaft 5, the sliding portion between the connecting rod 4 and the piston 3, the sliding portion between the piston 3 and the cylinder 2, and the like. .

As shown in FIG. 4, the cylinder head cover 22 has a substantially square contour in plan view, and an inner cover 23 is provided inside the cylinder head cover 22 as shown in FIGS. Have been.

The inner cover 23 is used to form a ceiling compartment defined by a ceiling portion in the cylinder head cover 22. The inner cover 23 covers the ceiling portion in the cylinder head cover 22, and the cylinder 2 stands upright or inclined. It is disposed in the cylinder head cover 22 so as to widely cover the valve driving unit 24 of the internal combustion engine 1 which is disposed. And this ceiling room is divided into three rooms A, B, and C according to each function.

The chambers A, B and C are formed as follows. As shown in FIGS. 3 and 4, the outer surface of the ceiling wall 26 of the inner cover 23 has a meandering wall 27 bent a plurality of times in a U-shape, and a right angle so as to substantially follow the meandering wall 27. A plurality of bent walls 28 are formed so as to abut against the inner surface of the ceiling wall of the cylinder head cover 22, respectively, and the meandering wall 27, the bent wall 28, and the ceiling wall of the inner cover 23 are provided. 26, the above-described chambers A, B, and C are respectively formed in the ceiling chamber by the ceiling wall and the peripheral wall of the cylinder head cover 22.

The chamber A communicates with an oil passage 29 in the cylinder head cover 22 that communicates with the oil passage 21. Therefore, the lubricating oil flowing in the oil passage 21
The oil enters the oil passage 29 and flows into the chamber A from there.

The oil passage 29 is provided in the cylinder head cover 22
And an elongated bent piece 30 having a substantially arc-shaped cross section attached to one corner of a substantially square peripheral wall in plan view, and one corner of the substantially square peripheral wall in plan view of the inner cover 23. This is an elongated passage formed by being surrounded by the concave portion 31, and has a cross-sectional shape in which a circle is slightly crushed (see FIG. 4).

A plurality of refueling discharge ports (holes) 32a, 32b, 33a, 33b are formed in a region (a ceiling wall portion) 26a of the ceiling wall 26 of the inner cover 23 which faces the room A, respectively. Further, at the base of the two small U-shaped bent portions of the meandering wall 27, oil supply discharge ports (holes) 32c and 33c for communicating the chamber A with the internal space of the internal cover 23 are formed, respectively ( 1 and 4).

The area 26c of the ceiling wall 26 of the inner cover 23 facing the room C is, as shown in FIG.
And the area 26b facing the chamber B, so that two of the meandering walls 27 are
At the base of two small U-shaped bends, lubrication outlets 32c, 33c
Is formed, the chamber A can be communicated with the internal space of the internal cover 23.

The three refueling outlets 32a, 32b, 32c are formed in a straight line, and the three refueling outlets 33a, 33b, 33c are also formed in a straight line. ing.

Thus, the three refueling discharge ports 32a, 32b
, 32c from the contact point with the push rod 14 at one end of one rocker arm 25 in the valve train drive unit 24,
Lubricating oil can be supplied to a total of three places, that is, a rotation support point substantially at the center and a contact point of the intake valve at the other end with the stem head 34.

In addition, the three oil supply outlets 33a
, 33b, 33c, the contact point of the other end of the other rocker arm 25 in the valve drive unit 24 with the push rod 14, the pivot support point substantially at the center thereof, and the exhaust valve at the other end. The lubricating oil can be supplied to a total of three locations including the contact point with the stem head (not shown).

In addition, in the places where lubrication is required in the valve drive unit 24, a necessary number of oil supply discharge ports are provided in the area 26a facing the room A in the ceiling wall 26 of the inner cover 23 in correspondence with the above places. By forming, lubricating oil can be easily supplied. In this manner, the chamber A functions as a large oil passage (oil supply passage). If the chamber A is communicated with the chamber C and the oil supply discharge port is formed also in the area 26c facing the chamber C, it is possible to supply lubricating oil to more various places.

The chamber B is a breather chamber (breather passage), and a breather chamber entrance 35 communicating with the crank chamber D is provided at one end of the chamber B curved in a hook shape with a ceiling wall 26. A rectangular opening is formed through the region 26b.

The blow-by gas containing the lubricating oil flowing from the breather chamber inlet 35 flows through the chamber B while being bent by the plurality of baffles 36 disposed in the chamber B, during which the lubricating oil is discharged. It is separated and dropped from the refueling outlet (hole) 37 into the internal space of the inner cover 23.

Then, the blow-by gas from which the lubricating oil has been separated passes through an exhaust pipe 38 formed near the other end of the chamber B and protruding from another corner of the substantially square peripheral wall of the cylinder head cover 22 in plan view. The air is then returned to the air cleaner (not shown).

A short protruding wall 22a is formed on the inner surface of the ceiling wall of the cylinder head cover 22 so as to fit into the elongated passage formed by the meandering wall 27 and the bent wall 28 defining the chamber C. I have. Although not shown in detail, the protruding wall 22a extends so as to connect the left and right portions of the elongated passage divided into right and left in FIG.

By fitting the protruding wall 22a into an elongated passage formed by the meandering wall 27 and the bent wall 28, the space between the chambers A and B is further sealed. The lubricating oil slightly leaking from the chamber A and the lubricating oil contained in the blow-by gas leaking slightly from the chamber B are in the area 26c of the ceiling wall 26 facing the chamber C.
Is dropped into the internal space of the inner cover 23 from the hole formed at the appropriate position.

In FIG. 1, reference numeral 42 denotes an ignition plug, and in FIG.
This is a bolt insertion hole for attaching to a bolt.

Since the present embodiment is configured as described above, the following effects can be obtained. A ceiling room (chamber A) formed on the ceiling in the cylinder head cover 22
To C), an oil supply passage (chamber A) for supplying oil to the valve drive unit 24 and a breather passage (chamber B) for separating lubricating oil from blow-by gas are formed separately.

As a result, a special oil supply pipe for supplying oil to the valve drive unit 24 is not required, and the arrangement of the oil supply pipe is simplified, and the lubrication structure is simplified.

The oil supply passage (chamber A) is relatively freely provided in the ceiling room formed in the ceiling portion of the cylinder head cover 22.
And refueling outlets (refueling points) 32a, 32b, 32c, 33a,
33b and 33c can be formed, so that the valve drive 24
In particular, the degree of freedom in forming the refueling discharge port in the lubricating structure can be improved.

In addition, this makes it possible to optimally lubricate a wide variety of lubricating points in the valve drive unit 24, thereby improving lubrication efficiency and reducing the amount of lubrication. Can be improved in durability.

Further, an oil supply passage (chamber A) having a lubricating oil supply function and a breather passage (chamber B) having a breather function are provided.
The partition can be formed in a ceiling room formed in the ceiling portion in the cylinder head cover 22, and the functional members can be shared. In addition, the size around the cylinder head 40 can be reduced.

The ceiling chamber is defined by an inner cover 23. The inner cover 23 is formed by a cylinder head cover 22.
The cylinder 2 is disposed in the cylinder head cover 22 so as to cover a ceiling portion thereof and widely cover the valve driving unit 24 of the internal combustion engine 1 in which the cylinder 2 stands.

As a result, the formation of the ceiling chamber in the ceiling portion of the cylinder head cover 22 becomes extremely easy, and the formation of a large chamber becomes easy. In particular, the formation of the lubrication discharge port in the lubrication structure of the valve drive unit 24 is facilitated. The degree of freedom can be further improved.

The individual chambers A to C constituting the ceiling chamber in the ceiling portion of the cylinder head cover 22 are composed of a meandering wall 27 erected on the outer surface of the ceiling wall 26 of the inner cover 23 and a bent wall.
By variously changing the bent shape of the valve drive unit 28, various shapes can be easily formed, and the lubrication demand of the valve drive unit 24 can be very easily met.

In addition, since the individual chambers A to C can be easily formed in various shapes as described above, the breather passage (chamber B) for separating the lubricating oil from the blow-by gas is provided in an optimal maze. It can be formed in a structure, and the breather performance can be improved.

Further, the inner end of an oil pump 8 is fitted to the right end of the crankshaft 5, and the oil pump 8
Are directly driven by the crankshaft 5. The oil pump 8 is housed in a recess 11 formed on the back surface of a cover 10 that closes the opening of the timing cam chamber 9.

As a result, the number of parts and the number of assembly steps can be reduced, and the oil pump 8 can be made compact. In addition, since the oil pump 8 can have a compact structure, the degree of freedom in the layout of peripheral parts is improved, and the degree of freedom in the design of the internal combustion engine 1 is also improved.

Since the inner part of the oil pump 8 is driven by the end of the crankshaft 5, the oil pump 8
It is easy to form an oil passage extending from each of the sliding portions (the bearing portion of the crankshaft 5, the sliding portion between the connecting rod 4 and the crankshaft 5, etc.) in the crank chamber, and the number of processing steps can be reduced.

Further, since the oil passage 20 is formed on the back surface of the cover 10, the oil passage 20 can be formed by a mold, and the number of processing steps can be reduced from this surface. Thus, the number of processing steps for the oil passage connected to the oil pump 8 can be reduced.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view of an internal combustion engine to which a lubrication structure of a valve train driving section according to an embodiment of the invention described in claims 1 and 2 of the present application is applied.

FIG. 2 is a schematic right side view of a power unit including the internal combustion engine of FIG. 1, with a part cut away.

3 is a vertical sectional view taken along line III-III of FIG. 1 and is a partially enlarged view of FIG. 2;

FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is a rear view of a cover that covers a timing cam chamber of the internal combustion engine of FIG. 1;

FIG. 6 is a plan view of a set plate for setting an oil pump used in the internal combustion engine of FIG. 1;

[Explanation of symbols]

0 ... power unit, 1 ... internal combustion engine, 2 ... cylinder (cylinder), 3 ... piston, 4 ... connecting rod, 5 ... crankshaft, 6 ... crankcase, 7 ... ball bearing, 8 ... oil pump, 9 ... timing cam chamber, 10… cover, 11…
Recess, 12 set plate, 13 valve operating mechanism, 14 push rod, 15 timing cam mechanism, 16 cam gear, 16
a ... rotating shaft, 17 ... swinging member, 17a ... swinging shaft, 18-21 ... oil passage, 22 ... cylinder head cover, 22a ... protruding wall, 23
... inner cover, 24 ... valve drive, 25 ... rocker arm,
26 ... ceiling wall, 26a-26c ... area (ceiling wall part), 27 ... meandering wall, 28 ... bent wall, 29 ... oil passage, 30 ... slender bent piece,
31 ... recessed part, 32a-32c, 33a-33c ... refueling discharge port (hole), 34 ... stem head, 35 ... breather chamber entrance, 36 ...
Baffle plate, 37: Oil supply outlet (hole), 38: Exhaust pipe, 39: Bolt insertion hole, 40: Cylinder head, 41: Driven gear,
42 ... spark plug, 43 ... oil passage, 44 ... crank pin, 45,
46 ... oil passage, 47 ... opening, 50 ... power transmission device, 51 ... power unit case, 52 ... bracket, 53 ... pedal shaft,
54 ... cell motor, 55 ... oil pan, A ... chamber (oil supply path),
B: chamber (breather passage), C: chamber, D: crank chamber,
E, F ... arrows.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G013 AA02 AA04 AB02 BA03 BB03 BB19 BC15 BC16 BC22 BD22 BD23 CA00 3G015 AA02 AA04 AB02 BD10 BD24 BE05 BE07 BE13 BE15 BF07 CA05 DA01 DA11 EA26

Claims (2)

[Claims] 1. A chamber is formed in a ceiling portion in a cylinder head cover, and an oil supply passage for supplying oil to a valve operating portion and a breather passage for separating lubricating oil from blow-by gas are formed on the same plane. A lubricating structure for a valve drive unit of an internal combustion engine, wherein the lubricating structure is formed separately. 2. The chamber is defined by an inner cover, and the inner cover covers a ceiling portion in the cylinder head cover and widely covers the valve operating portion of the internal combustion engine in which a cylinder stands. 2. The lubricating structure for a valve operating portion of an internal combustion engine according to claim 1, wherein said lubricating structure is disposed within said cylinder head cover.