JPH0942052A - Skirt lubricating piston - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve seizure resistance of a piston by well lubricating a skirt part of the piston increasing a thermal load to be placed in a severe condition, and improving formation of an oil film, in the piston lessening a compression height in order that a high output engine is formed into small size to lighten weight. SOLUTION: In a skirt lubricating piston 1 which is a piston for an engine to have a cooling shaker hole 2 in a head part of the piston, a hole for connecting one or more of the shaker holes to a piston periphery is provided in a skirt part 6 of a groove lower part of an oil ring on a thrust side and an opposite thrust side of the piston.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine piston, and more particularly to a skater having a shaker hole for cooling the head of the piston of a diesel engine and having a hole communicating with the skirt portion. -G Refueling type piston.

[0002]

2. Description of the Related Art Conventionally, the following three cases will be described with reference to the drawings as typical examples in which a piston shaft has a shaker hole for cooling in a high output diesel engine. First
The example is the piston with the head and skirt integrated, the second
A case is a piston and a two-divided piston in which the head and the skirt are separated, and a piston in which the head and the skirt are sealed by a seal body. The third case is the piston and the head. It is a two-piece piston that separates the skirt and the skirt, with no seal between the head and the skirt. First, the piston in which the head and the skirt are integrated in the first case will be described.
FIG. 8 shows a sectional view of the piston, and FIG. 9 shows a view of FIG. 8 seen from below. In the piston 10, the combustion chamber 7 is formed in the head portion, and a ring groove for controlling the gas seal and the oil is provided in the upper portion of the cylinder portion of the piston. The top ring groove 8 and the second ring groove 9 have a wedge shape on both the upper and lower surfaces of the groove in order to prevent the piston ring and the ring groove from being fixed by the carbon.
Further, a shaker hole 2 for cooling is formed in an annular shape on the head of the piston. Four holes 3 for the inlet and outlet of cooling oil are provided below the shaker hole and communicate with the inside of the piston.

Next, the operation will be described with reference to FIG. 8 and FIG. 9 for cooling the piston head and supplying oil to the skirt portion, and FIG. 4 for explaining the behavior of the piston. The cooling of the piston head enters the piston cooling nozzle 15 from an oil gallery of an engine (not shown). The tip of the piston cooling nozzle 15 has a passage narrowed to increase the flow velocity and is injected toward the piston 10 (two points). (Indicated by a chain line), the injected lubricating oil enters the annular shaker hole 2 through the hole 3a of the piston 10,
It flows in the circumferential direction, cools the head of the piston, flows out from the hole 3b (illustrated by the dotted line), and returns to the oil pan. The skirt 6 of the piston 10 is supplied with lubricating oil from a crank shaft (not shown) and a bearing of the connecting rod, which is spattered as splashes by the rotating and swinging motions of the crank shaft and the connecting rod and adheres to the inner wall of the cylinder-liner. To form. After that, it is scraped off by the piston 10 and returned to the oil pan. The behavior of the piston will be described with reference to FIG. FIG. 4 shows that the piston moves from the top dead center to the bottom dead center while inclining to the thrust side and the anti-thrust side in each stroke of the 4-cycle engine, that is, in the intake stroke, compression stroke, explosion stroke, and exhaust stroke. Shows. The symbols in the figure indicate the position of the piston in each stroke. The piston in the intake stroke descends from top dead center to position S1, position S2, position S3, and reaches bottom dead center. At the position S1 of the top dead center, the piston is inclined and pressed toward the thrust side, and the movement of the position S1 to the position S2 changes the inclination direction of the piston from the thrust side to the anti-thrust side. Further, the movement of the position S2 to the position S3 changes the inclination direction of the piston from the anti-thrust side to the thrust side. The piston in the compression stroke rises from bottom dead center to position C1, position C2, position C3, and reaches top dead center. At the position C1 at the bottom dead center, the piston is tilted and pressed toward the thrust side as at the position S3, and the tilt direction of the piston changes from the thrust side to the anti-thrust side by the movement from the position C1 to the position C2. Further, the movement of the position C2 to the position C3 causes the direction of inclination of the piston to move to the anti-thrust side. The piston in the explosion stroke descends from top dead center to position P1, position P2, position P3, and reaches bottom dead center. The position P1 of the top dead center of the piston is the position P1 from the side of the thrust opposite to the end position C3 of the compression stroke due to the explosion.
It changes abruptly in the thrust direction of the. Position P1,
The position P2, the position P3, and the piston are inclined and pressed toward the thrust side to move. The piston in the exhaust stroke rises from bottom dead center to position E1, position E2, position E3, and reaches top dead center. At the position E1 at the bottom dead center, the piston is inclined and pressed toward the thrust side in the same manner as the position P3, and the movement of the position E1 to the position E2 changes the direction of inclination of the piston from the thrust side to the anti-thrust side. Furthermore, from position E2 to position E
With the movement of 3, the inclination direction of the piston moves to the thrust side. As described above, when the behavior of the piston for each stroke is summarized, the thrust side, the anti-thrust side during the stroke of the piston change in the intake stroke, the compression stroke, and the exhaust stroke. Only in the explosive stroke, the piston tilts and moves toward the thrust side, and since the thrust load is large, the oil film is not formed well, and in the previous stroke, the piston is better lubricated to the skirt in the compression stroke. It is necessary to improve the formation of oil film.

The second case is a two-divided piston in which the head of the piston and the skirt are separated, and a piston in which the head and the skirt are sealed by a seal body. 1018
It is known from Japanese Patent No. 56. Configuration of the two-divided piston,
The operation will be described with reference to FIGS. FIG.
0 is a cross-sectional view perpendicular to the piston pin, and FIG. 11 is FIG.
FIG. The shaker hole 23 of the split piston 30 is formed in an annular shape between the head 24 and the skirt 25, and there is a gap 26 between the head 24 and the skirt 23. An annular seal body 27 for shielding is interposed. The seal body 27 fits in an annular groove 29 formed along an outer wall 28 provided on the top of the skirt 25,
The top peripheral surface 31 of the seal body 27 is brought into contact with the lower surface 32 of the head portion 24 to seal the gap 26. In operation, the lubricating oil sprayed from the piston cooling nozzle (not shown) enters the annular shaker hole 23 from the gap 33 on the lower surface of the piston 30 through the arrow 34a, flows in the circumferential direction, cools the piston head, and creates a gap. It flows out from 33 through an arrow 34b and returns to the oil pan. Note that the lubrication of the skirt portion and the behavior of the piston are substantially the same as those in the first case, and therefore the description thereof will be omitted.

The third case is a piston and a two-divided piston in which the head and the skirt are separated. The structure and operation of the piston without a seal body between the head and the skirt are shown in FIG. Refer to and explain. Note that FIG. 12 shows a cross-sectional view in a direction perpendicular to the piston pin. A shaker hole 41 of the split piston 40 is formed in an annular shape between a head portion 42 and a skirt 43, and a circumferential gap 4 is formed between the head portion 42 and the skirt 43.
There are four. In operation, the lubricating oil injected from the piston cooling nozzle (not shown) enters the annular shaker hole 41 through the gap 45 on the lower surface of the piston 40 from the arrow 46a,
It flows in the circumferential direction, cools the head of the piston, flows out from the gap 45 through the arrow 46b and returns to the oil pan, and partly passes through the circumferential gap 44 and flows out through the arrow 47 to the skirt 43. The behavior of the piston is substantially the same as that of the first case, and the description thereof will be omitted.

[0006]

However, the conventional piston has the following problems. (1) A piston in which the head and the skirt of the first example are integrated, and a piston of the second example and the head and the skirt
It is a two-part piston that separates the head and the head
With a piston sealed with a seal,
The problem with the piston known in the Japanese Patent No. 01856 is that, in addition to high output, in order to reduce the weight and appearance of the engine, the compression height of the piston (the size from the piston pin to the head) is reduced. ing. As a result, the heat load increases and the condition becomes severe. On the thrust side and the anti-thrust side of the piston, there is a problem that the lubrication supply state between the skirt portion and the cylinder-liner sliding surface is poor, and the metal contact causes local heat generation and welding to easily cause the piston to seize. Lubrication supply between the scat part of the conventional piston and the cylinder-liner sliding surface is scattered as a droplet by the rotational movement and swinging movement of the crankshaft and connecting rod, and only adheres to the inner wall of the cylinder-liner to form an oil film. That was not enough. It is necessary to supply more lubrication to the thrust portion and the anti-thrust skirt portion of the piston.

(2) The piston of the third example and the two-part split piston in which the head and the skirt are separated.
The problem with pistons without a seal between them is that they consume more oil. Since the two-divided piston has a gap on the circumference between the head and the skirt, it flows out from the annular shaker hole to the skirt portion of the piston on the circumference, and the lubricating supply becomes excessive. . As a result, there is a problem in that the oil ring cannot be scraped off, the oil rises upward, enters the combustion chamber through the second ring and the top ring, and burns, resulting in a large consumption of oil.

(3) From the above three cases, there is a problem that the oil consumption increases even if the lubrication supply of the skirt portion of the piston is too large, and the piston is seized even if the lubrication supply is too small. There is a problem that it is easy. It is necessary to optimize the lubrication supply required on the thrust side and the anti-thrust side of the skirt where the piston tends to seize, and at the position below the groove of the oil ring.

The present invention relates to a skart refueling type piston having the above-mentioned conventional problems, and more particularly, it has a shaker hole in the head of the piston of a diesel engine and a thrust hole communicating with the skirt part. Side and / or anti-thrust side and below the groove of the oil ring where seizure is likely to occur, the amount of oil supply is increased to form a better oil film, without increasing the oil consumption, and the piston skirt The purpose is to improve the seizure property of the toe.

[0010]

In order to achieve the above object, in the first invention of the skart refueling type piston of the present invention,
In a skart refueling type piston for an engine piston having a shaker hole for cooling at the head of the piston, in the thrust side and / or the anti-thrust side of the piston and at the bottom of the groove of the oil ring -A skating refueling type piston characterized in that one or more holes are provided in the skirt portion to connect the shaker hole and the outer circumference of the piston.

According to the second invention of the skirt refueling type piston of the present invention, it has a head and a skirt divided into two parts, and
In a skat refueling type piston in which the head and the skirt are sealed by a seal body and a shaker hole for cooling the head is formed, at a thrust side and / or an anti-thrust side position. Further, a skirt refueling type piston characterized in that the seal body is provided with one or more holes communicating with the shaker hole and the outer circumference of the piston.

[0012]

According to the above-mentioned scat oil supply type piston, in the skat oil supply type piston having a shaker hole for cooling at the head of the piston, the oil is provided on the thrust side and / or the anti-thrust side of the piston. Since the skirt portion below the groove of the ring is provided with a hole for communicating one or more shaker holes with the outer circumference of the piston, during the vertical movement of the piston, the lubricating oil accumulated in the shaker hole is prevented. Due to the inertial action and the pressure difference between the shaker hole and the outer circumference of the piston, the lubricating oil flows out to the thrust side and / or the anti-thrust side skirt part from the shaker hole to form a better oil film. it can.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of a skirt refueling type piston according to the present invention will be described in detail below with reference to the drawings. 1, FIG. 2, FIG. 3 and FIG. 4 show a skart oil supply type piston of the present invention, in which the head of the piston and the skirt are integrated. The same components as those of the related art are designated by the same reference numerals and the description thereof will be omitted. 1 is a sectional view taken along line AA of FIG. 2, FIG. 2 is a bottom view of FIG. 1 seen from below, FIG. 3 is a sectional view taken along line BB of FIG. 1, and FIG. There is. In FIG. 1, a shaker hole 2 for cooling is formed in an annular shape on the head of a piston 1. Below this shaker hole 2, there are four holes 3 for cooling oil inlet and outlet,
(See FIG. 2) It is provided and communicates with the inside of the piston.
Also, in the passage of the shaker hole 2 for cooling, the thrust side and
Oil reservoir 4 and passage hole 5 on the anti-thrust side respectively
(See FIG. 3) is formed, and the passage hole 5 communicates with the upper portion of the skirt portion 6. The passage holes 5 are provided in the number and size required for skating refueling.

Next, the operation will be described. The lubricating oil injected from the piston cooling nozzle 15 is the piston 1
Through the inlet hole 3a into the annular shaker hole 2, flows in the circumferential direction, cools the piston head, flows out through the outlet hole 3b, and returns to the oil pan. Part of the oil is accumulated in the oil reservoirs 4 provided on the thrust side and the anti-thrust side, passes through the passage holes 5, and the lubricating oil flows out to the skirt portion 6 to form an oil film. The mechanism by which the lubricating oil flows out to the skirt portion 6 is due to the inertial action of the lubricating oil accumulated in the shaker hole and the pressure difference between the shaker hole and the outer circumference of the piston during the vertical movement of the piston. Lubricating oil flows out from the hole to the skirt. The relationship between the behavior of the piston and the outflow of lubricating oil to the skirt portion will be described for each stroke of the four-cycle engine with reference to FIG. FIG. 4 shows how the piston behaves from top dead center to bottom dead center in each stroke, that is, the intake stroke, the compression stroke, the explosion stroke, and the exhaust stroke. The symbols in the figure indicate the position of the piston in each stroke. The piston in the intake stroke descends from top dead center to position S1, position S2, position S3, and reaches bottom dead center. In the intake stroke, the inertia of the lubricating oil accumulated in the shaker hole works upward, the shaker hole and the outer circumference of the piston are offset, and there is no pressure difference, and the outflow to the skirt portion is reduced. However, in the vicinity of the bottom dead center of the position S3, the inertia acts downward due to the deceleration of the piston 1, so that it flows out from the anti-thrust side to the skirt portion to form an oil film. The piston in the compression stroke rises from bottom dead center to position C1, position C2, position C3, and reaches top dead center. In the compression stroke, the inertia of the lubricating oil accumulated in the shaker hole works downward, and the position C1 of the bottom dead center is the same as the position S3 and flows out from the anti-thrust side to the skirt portion to form an oil film. . At the position C2, the inertia of the lubricating oil works downward, and a negative pressure is generated due to a large clearance on the thrust-side outer periphery of the piston, so that the oil flows out from the thrust side to the skirt portion to form an oil film. In the vicinity of the top dead center at the position C3, the inertia acts upward due to the deceleration of the piston 1, so that the outflow to the skirt portion is reduced. The piston in the explosion stroke descends from top dead center to position P1, position P2, position P3, and reaches bottom dead center. The position P1 of the top dead center suddenly changes from the position C3 at the end of the compression stroke to the position P1 due to the explosion, and the inertia of the lubricating oil works upward, but the negative pressure on the outer circumference of the piston on the anti-thrust side increases and the anti-thrust occurs. It flows from the side to the skirt and forms an oil film. At the position P2, the inertia of the lubricating oil works upward as in the intake stroke, the shaker hole and the outer circumference of the piston are offset, and there is no pressure difference, and the outflow to the skirt portion is reduced. However, in the vicinity of the bottom dead center of the position P3, the inertia acts downward due to the deceleration of the piston 1, so that it flows out from the anti-thrust side to the skirt portion to form an oil film. The piston in the exhaust stroke rises from bottom dead center to position E1, position E2, position E3, and reaches top dead center. Similar to the compression stroke, the inertia of the lubricating oil accumulated in the shaker hole works downward in the ascending stroke, and the position E1 of the bottom dead center is the same as the position P3, and the skid from the side opposite to the thrust side.
It flows out to the outer part and forms an oil film. At the position E2, the inertia of the lubricating oil works downward, and further, the outer circumference of the piston becomes a negative pressure and flows out from the thrust side to the skirt portion to form an oil film. In the vicinity of the top dead center of the position C3, the inertia acts upward due to the deceleration of the piston 1, so that the outflow to the skirt portion is reduced. that's all,
Summarizing the behavior of the piston for each stroke and the relationship that the lubricating oil flows out to the scat part, the behavior of the piston changes between the thrust side during the stroke of the piston and the anti-thrust side during the intake stroke, compression stroke, and exhaust stroke. Along with that, the outflow of lubricating oil also changes. Only in the explosion stroke, the piston is tilted and moved toward the thrust side, and the thrust load is large, but in the compression stroke, which is the previous stroke, the inertia of the lubricating oil accumulated in the shaker hole is downward due to the piston rising. It works, and the outer circumference on the thrust side of the piston becomes negative pressure, and it flows out from the thrust side to the skirt part and a good oil film is formed, so the piston moves in a good condition without running out of oil film in the explosion stroke. ..

Next, a second embodiment of the skart refueling type piston according to the present invention will be described with reference to the drawings. 5, FIG. 6, and FIG. 7 are two-divided pistons in which the head and the skirt of the piston of the present invention are separated, and a piston 20 in which the head and the skirt are sealed by a seal body. Is. The same components as those of the related art are designated by the same reference numerals and the description thereof will be omitted. 5 is a sectional view perpendicular to the piston pin, FIG. 6 is an enlarged sectional view of FIG. 5, and FIG. 7 is an AA sectional view of FIG. In FIG. 6, an annular seal body 21 that shields the gap 26 is interposed. The seal body 21 is fitted in an annular groove 29 formed along an outer wall 28 provided on the top of the skirt 25, and the top peripheral surface 31 of the seal body 21 is attached to the lower surface 32 of the head 24. The gap 26 is sealed by being brought into contact with each other. Passage holes 22 (see FIG. 7) are formed in the upper portion of the seal body 21 on the thrust side and the anti-thrust side, respectively, and the passage holes 22 communicate with the upper portion of the skirt portion 25. The passage holes 22 are provided in the number and size necessary for skating refueling. In operation, the lubricating oil injected from the piston cooling nozzle (not shown) enters the annular shaker hole 23 from the arrow 34a through the gap 33 on the lower surface of the piston 20, flows in the circumferential direction, cools the piston head, and the gap is formed. It flows out from 33 through an arrow 34b and returns to the oil pan. Part of the passage holes 22 are provided on the thrust side and the anti-thrust side of the annular shaker hole 23, respectively.
The lubricating oil flows out through the skirt portion 25 to form an oil film. Since the seal body 21 is flexible and is sealed, it does not flow into the skirt portion 25 except the passage hole 22. The mechanism by which the lubricating oil flows out to the skirt portion 25 is substantially the same as that of the first embodiment, and the description thereof will be omitted.

As described above, in both the first embodiment and the second embodiment, the lubricating oil is supplied to the skirt portion of the piston, the oil consumption is small, and a better oil film can be formed. In the above description, an embodiment in which one or more shaker holes and a hole for communicating with the outer circumference of the piston are provided in the skirt portion of the groove of the oil ring on the thrust side and the anti-thrust side of the piston is necessary. Thus, on the thrust side or the anti-thrust side of the piston, one or more shaker holes may be provided in the skirt portion of the lower portion of the groove of the oil ring to communicate with the outer circumference of the piston.

[0017]

As described above, according to the present invention,
Since the piston head has a shaker hole and a hole communicating with the skirt portion, the lubrication supply of the skirt portion is improved, an oil film can be formed, and the consumption of oil does not increase, and , The problem that the piston is easily seized is solved. As a result, the compression height of the piston can be reduced, and the weight of the engine and the external dimensions can be reduced. In addition, the formation of an oil film on the skirt portion is improved, and it is also one of the main causes of the mechanical noise of the diesel engine, which is also useful for improving the piston slap phenomenon.

[Brief description of drawings]

1 is a skart refueling type piston of the present invention, A- in FIG.
It is A sectional drawing.

FIG. 2 is a bottom view of the skating oil supply type piston of the present invention, FIG.

FIG. 3 is a skart refueling type piston of the present invention, B- in FIG.
It is B sectional drawing.

FIG. 4 is a diagram for explaining the operation of the skating oil supply type piston of the present invention and the prior art.

FIG. 5 is a cross-sectional view of a skates refueling type piston of the present invention.

FIG. 6 is an enlarged cross-sectional view of the skirt refueling type piston of the present invention, FIG.

FIG. 7 is a skirt refueling type piston of the present invention, A- in FIG.
It is A sectional drawing.

FIG. 8 is a sectional view of a prior art piston.

9 is a bottom view of the prior art piston, FIG. 8. FIG.

FIG. 10 is a sectional view of a prior art piston.

11 is an enlarged cross-sectional view of a prior art piston, FIG.

FIG. 12 is a sectional view of a prior art piston.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Skirt refueling type piston, 2 ... Shaker hole, 4 ... Oil reservoir, 5 ... Passage hole, 6 ... Skirt, 20 ... Skier
Refueling type piston, 21 ... Seal body, 22 ... Passage hole, 2
3 ... Shaker hole, 24 ... Head, 25 ... Skirt.

Claims (2)

[Claims] 1. A piston for an engine having a shaker hole for cooling at a head of the piston, wherein a skater on a thrust side and / or an anti-thrust side of the piston and below a groove of an oil ring. -A skating refueling type piston characterized in that one or more holes are provided in the skirt portion to connect the shaker hole and the outer circumference of the piston. 2. A head and a skirt divided into two,
And, in a piston in which a head and a skirt are sealed by a seal body and a shaker hole for cooling the head is formed, at a position on the thrust side and / or the anti-thrust side, and Shield one or more holes that communicate with the shaker hole and the outer circumference of the piston.
A skirt refueling piston characterized by being provided on the body.