JPH0536056U - Internal combustion engine pistons - Google Patents

Abstract

(57) [Abstract] [Purpose] A part of the engine oil from the oil jet injected toward the shaker part for cooling the groove bottom of the ring groove is utilized from this shaker part by utilizing the reciprocating motion of the piston. Provided is a piston of an internal combustion engine capable of positively cooling the back surface of the combustion chamber by discharging the crown portion toward the ceiling of the back surface of the combustion chamber and causing the crown portion to flow along the ceiling surface. A cooling groove is formed on the rear surface of the ring groove of the crown portion of the piston, and an annular oil reservoir is formed on the rear surface of the shoulder portion of the skirt portion in the circumferential direction of the piston facing the cooling groove. An oil discharge port for discharging engine oil is formed in the shaker portion formed by the oil sump toward the ceiling of the crown portion on the rear surface of the combustion chamber.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a piston provided with an annular shaker portion for shaking engine oil to cool the bottom of the piston ring groove, and also to a piston of an internal combustion engine capable of cooling the ceiling portion of the crown portion.

[0002]

[Prior Art]

 In recent years, the output of the engine has increased and the amount of heat generated has increased, which causes problems such as scuffing of the piston ring and wear of the piston ring. Therefore, as shown in FIG. 4 which is a cross-sectional view of the piston 1 taken along the line AA in plan view in FIG. In addition to forming the groove 4a, an oil reservoir 4b facing the cooling groove 4a is formed on the back surface of the shoulder portion 5a of the skirt portion 5, and the shaker portion 4 is formed by the cooling groove 4a and the oil reservoir 4b. O is allowed to swing up and down in the shaker portion 4 as indicated by arrow B in the figure.

The shaker portion 4 is formed in an annular shape in the circumferential direction of the piston 1 as shown in FIG. 5 in a section, and, on the other hand, as shown in FIG. 6, the bottom portion of the oil sump 4b is formed. An oil supply hole 6 is formed in this, and engine oil O injected from an oil jet 7 is introduced into the oil sump 4b from this oil supply hole 6. The shaker section 4 as described above shakes the engine oil O accumulated therein up and down by utilizing the reciprocating motion of the piston 1, as in the shaker section of Piston proposed in Japanese Patent Laid-Open No. 54-47937. By this, the groove bottom 3a of the ring groove 3 is cooled to prevent scuffing of the piston ring 8 and reduce wear.

[0004]

[Problems to be solved by the device]

 However, in such a piston, most of the engine oil injected from the oil jet is supplied to the shaker part, which is the hollow part on the back surface of the wall where the piston ring is installed on the front surface, and therefore the piston crown part. Almost no engine oil is blown to the rear part of the combustion chamber, and the temperature of the ceiling near the combustion chamber becomes extremely high. And, in the worst case, it was confirmed that cracks would occur in this ceiling.

On the other hand, in addition to the oil jet that supplies the engine oil to the oil sump, it is difficult to install an oil jet for spraying the engine oil on the ceiling part of the crown part in terms of installation space. Is the reality. In view of the above problems, the present invention transfers a part of engine oil from an oil jet injected toward a shaker portion for cooling the groove bottom of the ring groove to the reciprocating motion of the piston from the shaker portion. To provide a piston for an internal combustion engine that can positively cool the back surface of the combustion chamber by discharging it toward the ceiling of the back surface of the combustion chamber in the crown portion and flowing along the ceiling surface. It is intended for.

[0006]

[Means for Solving the Problems]

 The piston of the internal combustion engine according to the present invention for achieving the above object has a cooling groove formed on the back surface of the ring groove of the crown portion of the piston and a piston facing the cooling groove on the back surface of the shoulder portion of the skirt portion. A structure in which an annular oil reservoir is formed in the circumferential direction, and an oil outlet for discharging engine oil is formed in the shaker portion formed by the cooling groove and the oil reservoir toward the ceiling of the combustion chamber rear surface of the crown portion. Is.

If this oil discharge port is formed in a direction orthogonal to the axial direction of the piston pin, the effect of discharging oil is particularly high due to the relationship of the swinging direction of the piston. Further, depending on the amount of engine oil supplied from the oil jet, an appropriate number of oil discharge ports may be provided so that a predetermined amount of engine oil remains in the oil sump.

[0008]

[Work]

 Since the piston of the internal combustion engine of the present invention has the above-mentioned structure, a part of the engine oil accumulated in the oil sump due to the forward and backward movement of the piston is partially exhausted from the oil discharge port to the ceiling of the crown combustion chamber rear surface. Since the engine oil is discharged toward the ceiling and the engine oil is splashed on the ceiling, it becomes possible to cool the ceiling, which tends to be hot near the combustion chamber, and thermal deformation causes cracks in the ceiling. Such an accident can be prevented in advance.

[0009]

【Example】

 Next, an embodiment in which the present invention is applied to a two-piece piston in which a crown portion and a skirt portion are formed as separate bodies will be described with reference to the drawings. As shown in FIG. 1, the piston 1 is integrated by inserting a piston pin 10 into a piston pin hole 9 formed in a crown portion 2 and a skirt portion 5 which are separate bodies. A snap ring 11 is fitted and fixed so as not to come off from the piston pin hole 9. A metal 12 is provided on the outer circumference of the piston pin 10 to prevent abrasion of the sliding contact portion between the piston pin 10 and the crown portion 2.

On the other hand, on the back surface of the ring groove 3 on the outer periphery of the crown portion 2 into which the piston ring 8 is fitted, a cooling groove 4 a of a shaker portion 4 which is long in the axial direction of the piston 1 is formed, and a skirt portion 5 is formed. An oil reservoir 4b of the shaker portion 4 is formed on the back surface of the shoulder portion 5a, and the opening end of the cooling groove 4a and the opening end of the oil reservoir 4b are arranged to face each other to form one chamber. is doing.

The engine oil O accumulated in the oil sump 4b is supplied by being jetted from an oil jet 7 as shown in FIG. 6, and as the piston 1 reciprocates, as shown by an arrow B in FIG. It is shaken up and down in the shaker section 4. As a result, the groove bottom 3a of the ring groove 3 is cooled, scuffing of the piston ring 8 is prevented, and wear of the piston ring 8 is also reduced.

Further, in the compression stroke and exhaust stroke of the piston 1, a part of the engine oil O accumulated in the annular oil sump 4b is part of the ceiling portion of the crown portion 2 as shown in a partial cross section in FIG. From the oil discharge port 13 formed toward 2a, the oil is discharged as shown by an arrow C in FIG. 1, and engine oil O is sprinkled on the ceiling portion 2a. Then, it becomes possible to cool the ceiling portion 2a of the crown portion 2 which tends to become hot near the combustion chamber 14, and it is possible to prevent an accident such as cracking of the ceiling portion 2a due to thermal deformation. ..

By providing the oil discharge port 13 in a direction orthogonal to the axial direction of the piston pin 10, it is possible to particularly enhance the effect of discharging oil due to the relationship of the swing direction of the piston 1. In addition, depending on the amount of engine oil O supplied from the oil jet 7, if sufficient amount of engine oil O to cool the groove bottom 3a of the ring groove 3 remains in the oil sump 4b, this oil discharge port 13 may be formed by an appropriate number. Further, although the two-piece type piston has been described in the present embodiment, the present invention can be applied to a normal integral type piston.

[0014]

[Effect of the device]

 In the piston of the internal combustion engine of the present invention, a cooling groove is formed on the rear surface of the ring groove of the crown portion of the piston, and an annular oil reservoir is formed on the rear surface of the shoulder portion of the skirt portion in the circumferential direction of the piston facing the cooling groove. However, the shaker portion formed by the cooling groove and the oil reservoir is provided with the oil discharge port for discharging the engine oil toward the ceiling portion on the rear surface of the combustion chamber of the crown portion, and therefore the following effects can be obtained.

Since the oil discharge port is provided from the shaker part toward the ceiling part of the crown part, part of the engine oil accumulated in the oil sump due to the reciprocating motion of the piston moves from this oil discharge port to the crown part. It is discharged toward the ceiling behind the combustion chamber, and engine oil can be sprinkled on this ceiling. Then, since the ceiling part of the crown part, which tends to be high in temperature near the combustion chamber, can be cooled, it is possible to prevent the occurrence of cracks in the ceiling part due to thermal deformation. ..

[Brief description of drawings]

FIG. 1A of FIG. 3 in one embodiment of the piston of the present invention
FIG. 6 is an enlarged cross-sectional view taken along the line A.

FIG. 2 is a sectional view taken along line DD of FIG.

FIG. 3 is a plan view of a piston.

4 is an enlarged cross-sectional view of the conventional piston taken along the line AA of FIG.

5 is a cross-sectional view taken along line EE of FIG.

FIG. 6 is a cross-sectional view of essential parts showing a state in which engine oil is supplied from an oil jet to an oil sump.

[Explanation of symbols]

1 Piston 2 Crown 2a Ceiling 3
Ring groove 4 Shaker section 4a Cooling groove 4b
Oil sump 5 Skirt 5a Shoulder 13 Oil outlet 14 Combustion chamber O Engine oil.

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area F16J 1/08 7366-3J

Claims (1)

[Scope of utility model registration request] 1. A cooling groove is formed on the rear surface of the ring groove of the crown portion of the piston, and an annular oil reservoir is formed on the rear surface of the shoulder portion of the skirt portion in the circumferential direction of the piston facing the cooling groove to cool the cooling portion. A piston for an internal combustion engine in which a shaker portion formed by a groove and an oil reservoir is provided with an oil discharge port for discharging engine oil toward a ceiling of a combustion chamber rear surface of a crown portion.