JPH0814266B2 - Connection structure of piston and connecting rod - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for connecting a piston and a connecting rod in an internal combustion engine, and in particular, cooling oil from an oil jet is directed to an annular oil reservoir provided at the piston crown portion at the inlet on the opposite side in the circumferential direction. The present invention relates to a connecting structure of a piston and a connecting rod, which is divided into and flow into.

[0002]

2. Description of the Related Art Japanese Patent Application No. 2-226 filed by the present applicant
According to the connecting structure of the piston and connecting rod of No. 978, the swing center of the connecting rod with respect to the piston is much closer to the crown surface of the piston, as compared with the conventional connecting structure using the piston pin.
If the arm of the crankshaft and the connecting rod are lengthened by that amount, the displacement can be increased and the output of the engine can be increased without changing the dimensions of the cylinder.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the above-described connecting structure of the piston and the connecting rod, the partition plate is fitted into the annular space formed on the lower surface of the piston crown portion to partition the oil sump, and the partition plate is formed. A flow dividing wall protruding downward is provided on the ceiling wall of the oil reservoir so as to face the inlet provided so that the oil injected from the oil jet to the inlet of the partition plate is divided into the opposite side in the circumferential direction. . However, since the inlet consists of holes drilled in the partition plate, it is difficult for oil to efficiently flow into the oil sump, and the partition plate to be press molded has a complicated shape, and the inlet of the partition plate is There is a problem that it takes a lot of time to position the partition plate so as to be linearly arranged between the distribution wall of the oil sump and the oil jet (specifically, the inlet passage of the presser).

In view of the above-mentioned problems, the object of the present invention is to divide the oil into circumferentially opposite sides on the inlet side and efficiently flow into the oil reservoir without providing a flow dividing wall in the oil reservoir at the piston crown. It is an object of the present invention to provide a connecting structure of a piston and a connecting rod, which facilitates formation and assembly of a reservoir partition plate.

[0005]

In order to achieve the above object, in the structure of the present invention, a spherical convex portion and an empty portion surrounding the spherical convex portion are formed on the lower surface of the piston crown portion, and the tip end of the connecting rod is formed. The spherical concave portion of the formed receiving plate is slidably contacted with the spherical convex portion, the annular presser having the spherical concave portion slidably contacted with the lower surface of the receiving plate is supported by the skirt portion, and the annular partition plate is fitted in the empty portion. Partition the oil sump,
An inlet passage that guides the oil from the oil jet installed at the lower end of the cylinder to the oil reservoir is provided in the retainer. It is directed to a pair of entrances.

[0006]

Operation: A partition plate that closes the bottom of the oil sump at the piston crown by diverting the oil from the oil jet arranged at the lower end of the cylinder at the downstream end of the presser inlet passage to the opposite side in the circumferential direction. Flows into the oil reservoir through a pair of inlets. The oil smoothly flows into the oil reservoir from the pair of inlets in an inclined manner to the opposite side in the circumferential direction, and half-circulates the oil reservoir to flow out from the outlet of the partition plate.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a piston 2 according to the present invention is provided with a combustion chamber 4 having an asymmetrical depression on the upper surface of a crown 2a, and a plurality of ring grooves 3 in the upper half of the outer peripheral surface. The inner surface of the skirt portion 2b is formed into a screw hole. The axial center portion of the crown portion 2a is projected downward so as to surround the bottom portion of the combustion chamber 4, and the lower surface 7 of the protruding portion is flat. An oil sump 5 is formed on the lower surface 7 of the crown portion 2a by an annular space surrounding the protrusion.
Is formed. In order to reduce the weight and heat load of the crown portion 2a, an empty portion 8 is provided on the lower surface 7 of the crown portion 2a and is closed by a lid 8a.

In order to effectively cool the periphery of the combustion chamber 4 with oil, the bottom of the oil sump 5 is partitioned by an annular partition plate 6. The partition plate 6 is provided with an inlet 6a formed by cutting out the outer peripheral edge portion of the partition plate 6 and an outlet 6b formed by a through hole, with the phases of 180 ° different. Since the combustion chamber 4 is arranged asymmetrically in the crown portion 2a, the sectional shape of the oil sump 5, more specifically, the width of the oil sump 5 changes in the circumferential direction. The width of the annular partition plate 6 also changes according to the width of the oil sump 5. A cylindrical portion is formed by bending the inner peripheral edge portion of the partition plate 6, and the cylindrical portion of the partition plate 6 is the crown portion 2a.
It is fitted to the cylindrical portion 2c of the.

A sliding body 9 having a spherical convex portion 15 is superposed on the lower surface 7 of the crown portion 2a so as to be slidable. On the flat upper surface of the sliding body 9, an axial passage 13 for lubrication and an annular groove 1 are provided.
2 and are formed. Further, inside the sliding body 9, a plurality of passages 10 extending from the outer peripheral surface to the groove 12 and a plurality of passages 14 extending from the groove 12 to the spherical convex portion 15 are provided. Passage 1
The lower half of 3 has a large diameter in order to reduce the weight of the sliding body 9.

A bowl-shaped receiving plate 16 is integrally formed at the tip of the connecting rod 21, and a spherical concave portion 17 of the receiving plate 16 is slidably engaged with a spherical convex portion 15 of the sliding body 9. In order to maintain the engagement between the spherical concave portion 17 of the receiving plate 16 and the spherical convex portion 15 of the sliding body 9, the spherical convex portion 18 of the receiving plate 16 is slidably supported on the spherical concave portion 24 of the annular presser 23. To be done. The receiving plate 16 is provided with an axial passage 19 at substantially the center of the spherical recess 17, and is communicated with a passage 20 penetrating the connecting rod 21 in the front-rear direction.

The lower end surface of the presser foot 23 is screwed into the screw hole of the skirt portion 2b.
Held at 5. In order to prevent the holding cylinder 26 from loosening,
An annular groove 28 is provided on the inner surface of the skirt portion 2b, and a retaining ring 27 is engaged between the conical surface 28a of the annular groove 28 and the lower end surface of the holding cylinder 26. The retaining ring 27 is elastically expanded and deformed so that the lower conical surface engages with the conical surface 28a of the annular groove 28, regardless of the amount of screwing of the retaining cylinder 26.
Prevent slack.

In order to suppress the rotation of the piston 2 around the axis with respect to the connecting rod 21 and to allow the connecting rod 21 to swing left and right with respect to the piston 2, a pair of left and right in the meridian direction are formed in the spherical recess 24 of the presser 23. The groove 24a is formed and the receiving plate 16 is formed.
The sphere 29 coupled to the spherical convex portion 18 is engaged with the groove 24a. A ball 30 coupled to the inner surface of the upper wall of the sleeve 22 having an inverted L-shaped cross section that is externally fitted to the presser 23 is engaged with a hole in the upper end surface of the presser 23. Sphere 31 coupled to the outer peripheral surface of the sleeve 22
Is engaged with an axial groove 32 provided on the inner surface of the skirt portion 2b. For the convenience of assembling the presser foot 23 to the lower side of the receiving plate 16, the presser foot 23 is formed by combining two divided bodies in an annular shape, and the sleeve 22 is fitted onto the presser foot 23.

According to the present invention, the presser foot 23 is provided with the inlet passage 33 extending toward the inlet 6a of the partition plate 6, and the oil is supplied from the oil jet disposed at the lower end of the cylinder (not shown) toward the inlet passage 33. Is jetted.

As shown in FIGS. 2 and 3, the inlet 6 of the partition plate 6
a is a pair of notches provided on the outer peripheral edge of the partition plate 6,
The upstream end 33a of the inlet passage 33 of the retainer 23 is formed in a trapezoidal shape, and the downstream end 33b of the inlet passage 33 is opposite to the circumferential direction so that the oil flows into the pair of inlets 6a at an angle inclined to the opposite side in the circumferential direction. The downstream end 33b is directed toward the pair of inlets 6a of the partition plate 6 as a pair of channels that are inclined and branched.

The oil from the oil jet disposed at the lower end of the cylinder is shunted at the downstream end side of the inlet passage 33 of the presser 23 in an inclined direction to the opposite side in the circumferential direction, and further the partition plate 6 for closing the bottom of the oil sump. Through a pair of inlets 6a to the oil sump 5. When the oil separated in two hands enters the oil sump 5, it smoothly inclines toward the opposite sides in the circumferential direction and smoothly flows into the oil sump 5. It flows out from the outlet 6b.

In the above-mentioned embodiment, the piston crown portion 2
Although the sliding body 9 having the spherical convex portion 15 is brought into contact with the lower surface 7 of a, both may be integrally configured.

[0017]

As described above, according to the present invention, the spherical convex portion and the hollow portion surrounding the spherical convex portion are formed on the lower surface of the piston crown portion, and the spherical concave portion of the receiving plate formed at the tip portion of the connecting rod is convexly spherical. A ring-shaped presser having a spherical concave portion that is slidably contacted with the lower part of the receiving plate is supported on the skirt part, and an annular partition plate is fitted in the empty part to partition the oil sump and at the lower end of the cylinder. A pair of inlet passages for guiding the oil of the arranged oil jet to the sump are provided in the retainer, and the inlet passages are inclined and branched to the opposite side in the circumferential direction at the downstream end side, and are separated from each other in the circumferential direction on the partition plate. Since the oil is directed to the inlet of the oil reservoir, when the oil flows into the annular oil reservoir, it splits into two parts and flows in opposite directions, and flows out from the outlet on the side opposite to the inlet. Therefore, the circumference of the piston crown is cooled substantially uniformly, and the cooling performance of the piston is improved.

Since it is not necessary to provide a flow dividing wall in the oil sump of the piston crown, the construction of the piston is simplified, and the partition plate need only be positioned so as to coincide with the inlet passage of the presser foot during assembly. .

When the combustion chamber is asymmetrically provided in the crown portion of the piston, the sectional shape of the oil sump changes in the circumferential direction.
The partition plate can be of a simple shape and does not require a complicated process such as deep drawing to process the entrance, so molding is simple and the number of steps is reduced.

[Brief description of drawings]

FIG. 1 is a front sectional view showing a connection structure between a piston and a connecting rod according to the present invention.

FIG. 2 is a cross-sectional view showing a relationship between a partition plate and a passage of a retainer with respect to an oil sump of a piston crown portion in a circumferential direction.

FIG. 3 is a plan sectional view showing the shape of the entrance of the partition plate.

[Explanation of symbols]

 2: Piston 2a: Crown 2b: Skirt 5: Oil reservoir 6: Partition plate 6a: Inlet 6b: Outlet 15: Spherical convex portion 16: Receiving plate 17: Spherical concave portion 18: Spherical convex portion 21: Connecting rod 22: Sleeve 23: Presser foot 24: Spherical concave portion 33: Entrance passage

Claims (1)

[Claims] 1. A spherical convex portion and a hollow portion surrounding the spherical convex portion are formed on a lower surface of a piston crown portion, and a spherical concave portion of a receiving plate formed at a tip portion of a connecting rod is slidably contacted with the spherical convex portion to form a receiving plate. The skirt supports an annular presser having a spherical recess that slidably contacts the lower surface of
An annular partition plate is fitted in the empty part to divide the oil reservoir, and an inlet passage for guiding the oil of the oil jet arranged at the lower end of the cylinder to the oil reservoir is provided in the retainer, and the inlet passage is circumferentially opposite on the downstream end side. A connecting structure of a piston and a connecting rod, characterized in that the structure branches toward the side and is directed to a pair of inlets provided on the partition plate in a circumferentially spaced manner.