JP2001140615A - Crankshaft and internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve cooling performance of a back side of a piston, ensure strength thereby, reduce a temperature of a combustion chamber, and suppress generation of knocking by increasing an oil quantity for cooling in the back side of the piston. SOLUTION: In a crankshaft 1 provided with an oil passage for supplying lubricating oil to a large end bearing 6, a cutout part 9 communicated with an outside is disposed on a crank pin part end surface 8 of a crank web 4, and lubricating oil delivered from an oil clearance of the large end bearing 6 is injected to the back side of the piston 11 through the cutout part 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crankshaft used for oil cooling a piston and an internal combustion engine having the crankshaft.

[0002]

2. Description of the Related Art Conventionally, the strength of an aluminum piston used in an internal combustion engine decreases in proportion to an increase in operating temperature. Therefore, it is desired to improve the piston cooling performance.

[0003] Conventionally, as means for lowering the piston temperature, an oil jet cooler or an oil passage is provided in a connecting rod so as to ensure the strength of the piston. (250 ° C. to 245 ° C.).

[0004] Among these, in the system in which lubricating oil is splashed to a piston from an oil passage provided in a connecting rod, a notch is provided in a part of the circumference of an end surface of a large end, or a small-diameter hole is provided in the connecting rod. An oil passage is formed.

[0005]

However, when a notch is provided in a part of the circumference of the end surface of the large end of the connecting rod to provide an oil passage, care must be taken not to impair the strength due to the notch. However, since the position and the size are selected and provided, the shape is not such that a sufficient amount of oil can be obtained from the viewpoint of piston cooling.

[0006] Further, it is desired to increase the depth of the notch, but it is not possible to increase the depth due to restrictions on the strength of parts, and it was not possible to supply a sufficient amount of lubricating oil. Increasing the width of the notch made it easier for the lubricating oil to leak from the lubricating portion at the large end of the connecting rod, and did not lead to an improvement in the cooling effect of the piston.

Therefore, the present invention is to increase the amount of oil applied to the back side of the piston, improve the cooling performance on the back side of the piston, thereby ensuring the strength of the piston and lowering the temperature of the combustion chamber, thereby suppressing knocking. It is an object to provide a crankshaft that can be used and an internal combustion engine using the crankshaft.

[0008]

In order to achieve the above object, according to the present invention, there is provided a crankshaft provided with an oil passage for supplying lubricating oil to a large end bearing. A notch portion communicating with the outside is provided on the end face, and the lubricating oil discharged from the oil clearance of the large end bearing is ejected to the back side of the piston through the notch portion.

According to a second aspect of the present invention, in the crankshaft, the notch is formed so that lubricating oil is ejected toward the back side of the piston at the time of the top dead center of the piston of the crank web. It is characterized in that it is provided at the part closest to the piston.

According to a third aspect of the present invention, there is provided an internal combustion engine having the crankshaft according to the first or second aspect and a connecting rod attached to the crankshaft, wherein the connecting rod comprises: A notch portion communicating with the outside is provided at a position on the end face circumference of the large end corresponding to the notch portion provided on the crankshaft, and the notch portion provided on the crank web and the notch provided on the connecting rod are provided. The lubricating oil is spouted to the rear side of the piston when the notch coincides.

According to a fourth aspect of the present invention, there is provided an internal combustion engine, wherein the crankshaft according to any one of the first to third aspects is arranged vertically.

[0012]

Embodiments of the present invention will be described below.

[First Embodiment of the Invention] FIGS. 1 to 4 show a first embodiment of the present invention.

First, the structure will be described.
The crankshaft 1 is provided integrally with a crankpin 3 to which a connecting rod 2 is rotatably mounted, and a pair of crank webs 4 on the left and right with the crankpin 3 interposed therebetween. Further, at least one of the crank webs 4 and 4 is integrally provided with a crank journal 5 serving as a rotation shaft of the crankshaft 1.

A connecting rod 2 is rotatably attached to a crank pin 3 of the crank shaft 1 via a large end bearing 6.

FIG. 1 shows a state in which the piston 11 is at the position of the top dead center. The crankshaft 1 is provided with a crank web 4 from below the center of the crank journal 5 and above the center of the crank pin 3 through the crank web 4. A linear oil passage 7 penetrating through is formed.

As shown in FIG. 2 which is a cross-sectional view taken along the line AA of FIG. 1, a notch portion of one line communicating radially from the center of the crank pin 3 to the outside is formed in the end surface 8 of the crank pin portion of the crank web 4. 9 are formed. The notch 9 is provided on the opposite side of the center of the bounce weight 10 of the crank web 4 and the crank pin 3.

A notch 9 is provided at a position closest to the piston 11 so that lubricating oil is ejected toward the back of the piston 11 at the top dead center of the piston 11 where the temperature of the combustion chamber is the highest. ing.

FIG. 3 shows an appearance in which the crankshaft 1 of the present invention is applied to an engine of an outboard motor.

The outboard motor 11 has a vertically arranged crankshaft 1, a top cowling 12 and an upper case 13.
Each part of the engine is housed in a housing constituted by the lower case 14. Top cowling 1
Reference numeral 2 denotes an upper cowl 15, a bottom cowl 16, and an air duct cover 17. The upper case 13 has an upper part covered with an apron 18, and a propeller 19 is mounted on the lower case 14 below the upper case 13. The outboard motor 11 is rotatable left and right about a longitudinal axis 48 provided in the upper case 13 as viewed from a plane, and is also a rotating shaft 49 of the mounting member 20 fixed to the rear plate of the hull 21. It is attached so as to be able to rotate up and down when viewed from the front with the center as the center.

As shown in FIGS. 4 and 5, the outboard motor 11 is provided with a four-cycle, four-cylinder L-type engine 22 in which the cylinders are arranged in a vertical direction, between the bottom cowl 16 and the upper case 13. Is fixed to the upper surface of the exhaust guide 23 disposed in the upper side, and is housed in the top cowling 12 in the upper state with the upper surface side covered with a cover member (not shown).

FIG. 5 is a partial cross-sectional plan view showing the installation state of each component of the engine.

The main body of the engine 22 is composed of a head cover 29, a cylinder head 30, a cylinder block and a cylinder block 27 which forms a part of a crank chamber.
And the crankcase 31 are integrally connected along the longitudinal direction of the hull. The crankcase 31 is disposed so as to be the front of the hull, and the head cover 29 is disposed so as to be the rear of the hull.

The piston 11 has a cylinder 2 at its top.
8, a combustion chamber is formed, and reciprocates in the cylinder 28 by receiving the explosion pressure of the combustion gas to apply a rotational force to the crankshaft 1 via the connecting rod 2.

The engine 22 includes, as shown in FIG.
For an oil passage 24 provided in the engine body,
An oil pump 26 for sucking lubricating oil from an oil pan 25 disposed below the exhaust guide 23 is provided near the lower end of the crankshaft 1. The oil pump 26 is sucked by the oil pump 26 in the middle of the cylinder block 27. An oil filter 28 for filtering the lubricating oil is provided.

As shown in FIG. 4, the crankshaft 1 extending vertically in the crank chamber 32 of the engine 22 is formed on the joint surface between the cylinder block 27 of the engine body and the upper and bottom walls of the crankcase 31. Journal bearings 33 and 34, and journal bearings 3 provided in the crank chamber 32 at intervals between the cylinders in the vertical direction.
5 for pivoting.

In order to supply lubricating oil to the journal block 35, each of the cylinder block-side bearing components 36 of each journal bearing 35 is provided with an oil opening from the main oil passage 24 c to the journal block 35. Each of the passages 24d is formed.

Next, a method of cooling the piston when the crankshaft 1 according to the first embodiment is used will be described.

According to the outboard motor engine 22 using the crankshaft 1 according to the present invention, each journal bearing 3
In order to lubricate 3, 34 and 35, lubricating oil stored in an oil pan 25 disposed below the exhaust guide 23 is driven by an oil pump 26 provided near the lower end of the crankshaft 1 as shown in FIG. As shown by the arrow in
The cylinder block 2 is sucked up by the suction pipe 37 and is passed through the oil passage 24 c of the exhaust guide 23.
7, the oil is sucked into the oil pump 26, discharged from the oil pump 26 to the cylinder block 27 side, and then sent to the oil filter 28 through the oil passage 24b. After being filtered, the oil passes through the main oil passage 24c and is distributed to each of the oil passages 24d at the end.
3, 34, 35.

The lubricating oil supplied to the journal bearings 34 and 35 reaches the large end bearing 6 through an oil passage 7 extending from the crank journal 5 through the crank web 4 to the crankpin 3.

The lubricating oil that has reached the large end bearing 6 is
With this pressure, the oil is discharged from both ends through the oil clearance of the large end bearing 6, and the discharged lubricating oil is ejected to the outside through a notch 9 formed on the end face 8 of the crank pin 4 of the crank web 4.

Here, as described above, the crank web 4
The notch 9 formed at the end of the crank pin portion 8 at the position closest to the piston 11 allows the lubricating oil to be properly ejected toward the back of the piston at the top dead center of the piston 11, The lubricating oil hits when the piston 11 is at the highest temperature, and the piston 11 can be cooled most efficiently.

The oil supplied to each of the journal bearing portions 33, 34, 35 and lubricating the corresponding portions is finally returned to the oil pan 25 from the bottom of the crank chamber 32.
At that time, most of the lubricating oil that has fallen downward from the journal bearings 33, 34, 35 in the crank chamber 32 falls through the oil return hole 38 of the cylinder block side bearing component 36 and the like, and falls as it is. A part is rotated by the rotation of the crankshaft 1, and the guide plate 50
And adheres to the inner surface of the crankcase 31 on the back side thereof, and then flows down along them.

As described above, by providing the notch 9 in the end face 8 of the crank pin portion of the crank web 4, the width of the passage through which the lubricating oil is ejected is increased, the passage depth is increased, and the passage area is increased. Even so, problems on strength are reduced. And the amount of cooling oil applied to the back side of the piston can be increased, and the cooling performance on the back side of the piston is improved. Thereby, the strength of the piston can be ensured, the temperature of the combustion chamber also decreases, and the occurrence of knock is suppressed.

The oil supplied to each of the journal bearing portions 33, 34, 35 and lubricating the corresponding portions is finally returned to the oil pan 25 from the bottom of the crank chamber 32.
At this time, in the crank chamber 32, the lubricating oil that has fallen downward from the journal bearings 33, 34, 35 flows into the oil return hole 38 of the cylinder block side bearing component 36.
And fall as it is.

Second Embodiment FIGS. 6 to 8 show a connecting rod used in a second embodiment of the present invention. FIG. 6 is a front view of the connecting rod, and FIG. 7 is a plan view thereof. FIG. 8 is an explanatory view of a partial cross section showing a use state of the crankshaft according to the second embodiment.

The connecting rod 2 attached to the crankshaft 1 has a lower large end 14 and an upper small end 39.
And are integrally connected by a rod portion 40 having an I-shaped cross section.

The connecting rod 2 shown in FIG.
This is a so-called assembly type in which the large end portion 14 can be divided into two parts. That is, when attaching the connecting rod 2 to the crankshaft 1, the large end cover 41 is removed from the large end main body 42, the large end main body 42 is applied to the crankpin 3, and the large end cover 41 is attached from the opposite side. Crank pin 3
And assembling it by tightening the mounting screw 43.

The small end 3 of the upper part of the connecting rod 2
9 is provided with a small-end bearing 44, and the piston 11 is rotatably mounted via a piston pin 45 inserted into the small-end bearing 44 (see FIG. 5).

A notch 47 is formed in a part of the bearing end surface 46 of the large end 14 of the connecting rod 2 so as to radially communicate with the outside from the center of the crankpin 3.
As shown in FIG. 7, one notch 47 is formed on each of both sides of the bearing end surface 46 of the large end 14 of the connecting rod 2.

The position of the notch 47 is determined from a position slightly before the piston 9 corresponding to the notch 9 formed in the crankshaft 1 reaches the top dead center until the piston 11 reaches the top dead center.

The second embodiment of the present invention is characterized in that the crankshaft 1 described in the first embodiment of the present invention and the connecting rod 2 having the notch 47 formed in the bearing end surface 46 of the large end portion 14 are used in combination. And its operation will be described below.

While the rotary motion of the crankshaft 1 accompanying the reciprocating motion of the piston 11 is performed, as shown in FIG. 8, near the top dead center position of the piston 11, the end face 8 of the crank pin 4 of the crank web 4 A moment occurs when the formed notch 9 coincides with the notch 47 formed on the bearing end surface 46 of the large end 14 of the connecting rod 2.

At this moment, the lubricating oil that has been pressure-fed by the oil pump 26 and reached the large end bearing 6 is discharged from both ends of the large end bearing 6 through the oil clearance of the large end bearing 6 at that pressure. The discharged lubricating oil is supplied to the notch 9 formed in the end face 8 of the crank pin portion of the crank web 4 and the large end 14 of the connecting rod 2.
Is ejected to the outside through a passage having a large cross-sectional area formed by combining with a notch portion 47 formed in the bearing end surface 46.

Therefore, in the second embodiment, since the cross-sectional area of the oil passage of the jetting portion can be further increased, the amount of lubricating oil jetted is sufficient and the cooling effect is greater.

The other configuration and operation are the same as those of the first embodiment, and the description is omitted.

The present invention is not limited to the above embodiments, but can be applied to a cultivator and other engines having a vertically arranged crankshaft.

[0048]

As described above, according to the invention described in each claim, the notch is provided on the end face of the crank pin of the crank web, so that the passage width is increased and the passage depth is increased. Even if the passage area is increased, there is little problem in strength. And the amount of cooling oil applied to the back side of the piston can be increased, and the cooling performance on the back side of the piston is improved. As a result, the piston strength can be ensured, the combustion chamber temperature can be reduced, and the effect of suppressing knocking can be obtained.

Further, the lubricating oil jetted to the back side of the piston also has the effect of promoting the lubrication of the piston pin and the piston pin hole.

According to the second aspect of the present invention, in addition to the above-described effects, since the lubricating oil is jetted toward the back side of the piston at the time of the top dead center of the piston, the jetted lubricating oil has the highest temperature. The piston can be efficiently cooled because the piston accurately hits the rear side.

According to the third aspect of the present invention, the notches are provided in both the crank web and the connecting rod, and the positions of the notches are set so that the two notches coincide at the top dead center of the piston. As a result, the cross-sectional area of the oil passage of the ejection portion can be further increased, and the amount of oil further increases, thereby further improving the cooling effect.

According to the fourth aspect of the present invention, the amount of cooling oil applied to the back side of the piston can be increased, and the cooling performance on the back side of the piston is improved, so that an internal combustion engine having a high piston strength can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a partial cross section showing a use state of a crankshaft according to Embodiment 1 of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG. 1 showing the first embodiment.

FIG. 3 is an external view of a case where the crankshaft according to the first embodiment is applied to an engine of an outboard motor.

FIG. 4 is a front view of a partial cross section when the crankshaft according to the first embodiment is applied to an engine of an outboard motor.

FIG. 5 is a plan view of a partial cross section when the crankshaft according to the first embodiment is applied to an engine of an outboard motor.

FIG. 6 is a front view of a connecting rod used in a second embodiment of the present invention.

FIG. 7 is a plan view of a connecting rod used in the second embodiment.

FIG. 8 is an explanatory view of a partial section showing a use state of the crankshaft according to the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crank shaft 2 Connecting rod 3 Crank pin 4 Crank web 5 Crank journal 6 Large end bearing 7 Oil passage 8 Crack pin end face 9, 47 Notch section 11 Piston 46 Bearing end face

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16C 3/16 F16C 3/16 7/00 7/00

Claims (4)

[Claims] In a crankshaft provided with an oil passage for supplying lubricating oil to a large end bearing, a notch communicating with the outside is provided on an end face of a crank pin portion of a crank web, and discharge is performed from an oil clearance of the large end bearing. A crankshaft characterized in that the lubricating oil blows out to the back side of the piston through the notch. 2. The notch portion is provided at a portion of the crank web closest to the piston so that lubricating oil is ejected toward the back side of the piston at the time of top dead center of the piston. The crankshaft according to claim 1, wherein: 3. An internal combustion engine having the crankshaft according to claim 1 and a connecting rod attached to the crankshaft, wherein the connecting rod corresponds to a notch provided in the crankshaft. A notch that communicates with the outside is provided at the position of the end face circumference of the large end,
An internal combustion engine characterized in that when a notch provided in the crank web and a notch provided in the connecting rod coincide with each other, lubricating oil is ejected to the back side of the piston. 4. An internal combustion engine, wherein the crankshaft according to claim 1 is arranged vertically.