JPH0749828B2 - 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 more particularly to a sliding contact portion between a spherical convex portion of a piston crown portion and a spherical concave portion of a receiving plate of the connecting rod. The present invention relates to a connecting structure for connecting a piston and a connecting rod, which is prevented from rotating inward.

[0002]

2. Description of the Related Art According to the connection structure of the piston and connecting rod of Japanese Patent Application No. 2-85663 filed by the present applicant, the swinging center of the connecting rod with respect to the piston is greater than that of the conventional connecting structure using piston pins. Is much closer to the crown surface of the piston, and if the crankshaft arm and the connecting rod are lengthened by that much, the displacement can be increased and the engine output 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 spherical convex portion formed on the lower surface of the piston crown portion of the bowl-shaped receiving plate integrally formed at the tip portion of the connecting rod. The spherical concave portion is slidably supported, and the spherical convex portion on the lower surface of the receiving plate is slidably supported on the spherical concave portion of the annular retainer supported by the skirt portion. In this connecting structure, the piston can rotate around the central axis with respect to the connecting rod, so that there is the following problem. In a piston having an asymmetrical combustion chamber on its crown surface, the position of the fuel chamber relative to the fuel injection nozzle or the torch portion (internal combustion engine having a sub combustion chamber) shifts and combustion deteriorates. The recess that avoids the collision of the piston crown surface with the intake / exhaust valve shifts with respect to the intake / exhaust valve, and the piston collides with the intake / exhaust valve. The inlet of the annular cooling oil reservoir provided inside the piston crown portion deviates from the oil jet disposed at the lower end of the cylinder, and oil does not enter the oil reservoir.

In view of the above problems, the object of the present invention is to allow the swinging of the connecting rod at the sliding contact portion between the spherical convex portion of the piston crown portion and the spherical concave portion of the receiving plate of the connecting rod. It is to provide a connecting structure of a piston and a connecting rod that does not allow rotation of the piston.

[0005]

In order to achieve the above object, in the structure of the present invention, the spherical convex portion formed on the lower surface of the piston crown portion is provided with the spherical concave portion of the receiving plate formed at the tip portion of the connecting rod. A ring-shaped presser having a spherical concave part that slidably contacts the spherical convex part on the lower surface of the receiving plate is fitted and supported on the skirt part, and is joined to one of the spherical convex part of the receiving plate and the spherical concave part of the pressing part. The sphere is engaged with a meridional groove provided on the other side, and the sphere joined to one of the outer peripheral surface of the presser and the inner surface of the skirt is engaged with an axial groove provided on the other side.

[0006]

Since the sphere coupled to the outer peripheral surface of the presser engages with the axial groove provided on the inner surface of the skirt portion, the presser is moved in the axial direction of the piston to form a spherical convex portion of the piston crown. The clearance between the connecting rod and the annular recess of the receiving plate can be adjusted,
Relative rotation of the piston and the presser is prevented. Since the sphere connected to the spherical convex portion on the lower surface of the receiving plate is engaged with the groove in the meridian direction provided in the spherical concave portion of the presser plate, the connecting rod can swing as the crankshaft rotates, but Relative rotation is blocked.

[0007]

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 recess on the upper surface of a crown portion 2a, and a plurality of ring grooves 3 on 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 annular oil reservoir 5 is formed on the lower surface 7 of the crown portion 2a so as to surround the protruding portion. 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, an annular partition plate 6 is fitted and supported in the oil sump 5. 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. A sliding body 9 having a spherical convex portion 15 is superposed on the lower surface 7 of the crown portion 2a in a slidable manner.

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 on the lower surface of the receiving plate 16 has an annular pressing member 2.
It is slidably supported in the spherical concave portion 24 of No. 3. The receiving plate 16 is provided with an axial passage 19 substantially in the axial center of the spherical recess 17, and an outlet passage 20 penetrating the connecting rod 21 in the front-back direction.
Is communicated with.

The lower end surface of the presser foot 23 is screwed into the screw hole of the skirt portion 2b, and the step portion of the stepped holding cylinder 26, that is, the holding surface 2 is formed.
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. The presser foot 23 is provided with an inlet passage 33 that extends toward the inlet 6a of the partition plate 6.
Oil is jetted toward the oil jet from an oil jet provided at the lower end of a cylinder (not shown).

An axial passage 13 for lubrication and an annular groove 12 are formed on the flat upper surface of the sliding body 9. A plurality of groove passages 34 connecting the groove 12 and the passage 13 on the upper surface of the slide body 9.
Is provided. Inside the slide 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. The lower half of the passage 13 has a large diameter in order to reduce the weight of the sliding body 9.

The oil ejected from the oil jet is held by the presser 23.
Through the inlet passage 33 of the partition plate 6 and the inlet 6a of the partition plate 6, and is divided into two parts to cool the crown portion 2a of the piston 2 while half-circulating the oil reservoir 5 in the opposite direction, and the outlet on the opposite side. It flows out from 6b to the space below the partition plate 6. The oil in the empty space below the partition plate 6 flows into the groove 12 via the passage 10, and part of the oil in the groove 12 flows to the passage 19 via the groove passage 34 and the passage 13.
The sliding contact portion between the upper surface of the sliding body 9 and the lower surface 7 of the crown portion 2a is lubricated. The remaining oil in the groove 12 passes through the passage 14 and lubricates the sliding contact portion between the spherical concave portion 17 and the spherical convex portion 15 to flow into the passage 19. The oil in the passage 19 flows out of the connecting rod 21 through the outlet passage 20 and returns to the crank chamber (not shown). In addition, the oil in the empty space below the partition plate 6 is not covered with the spherical recess 24 of the presser 23 and the receiving plate 16.
Lubricate the sliding contact portion with the spherical convex portion 18 and return to the crank chamber.

According to the present invention, 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 to the left and right with respect to the piston 2, the presser foot 23 is provided.
A pair of left and right grooves 24a in the meridian direction are formed in the spherical concave portion 24, and a sphere 29 coupled to the spherical convex portion 18 of the receiving plate 16 is engaged with the groove 24a. The sphere 30 coupled to the inner surface of the upper wall of the sleeve 22 having an inverted L-shaped cross section that is fitted onto the presser foot 23 is
3 is engaged with the hole on the upper end surface. The sphere 31 coupled to the outer peripheral surface of the sleeve 22 is engaged with the 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 on the presser foot 23. At the time of assembling the presser foot 23, if a pin is driven into the combined portion of the divided members to firmly connect it to the sleeve 22, the connection by the ball 30 is not necessary.

In the embodiment shown in FIG. 2, instead of the balls 29 and 31 and the grooves 24a and 32 in the embodiment of FIG. 1, a ball 42 connected to the lower surface 7 of the crown portion 2a is replaced with a hole 43 on the upper surface of the sliding body 9. The sphere 44 coupled to the spherical concave portion 17 of the receiving plate 16 is engaged with one groove 15a in the meridian direction provided on the spherical convex portion 15 of the sliding body 9.

In each of the above-mentioned embodiments, the sliding body 9 having the spherical convex portion 15 is brought into sliding contact with the lower surface 7 of the crown portion 2a of the piston 2, but they may be integrally formed. Further, the arrangement of the sphere and the groove or hole with respect to the constituent members may be reversed.

[0017]

As described above, according to the present invention, the spherical convex portion formed on the lower surface of the piston crown portion is brought into sliding contact with the spherical concave portion of the receiving plate formed at the tip portion of the connecting rod so that the spherical surface of the lower surface of the receiving plate is formed. An annular presser having a spherical concave part that is in sliding contact with the convex part is fitted and supported on the skirt part, and a sphere that is connected to one of the spherical convex part of the receiving plate and the spherical concave part of the presser is provided on the other side in the meridian direction. Engage the groove,
Since the sphere connected to one of the outer peripheral surface of the presser and the inner surface of the skirt is engaged with the axial groove provided in the other, the swing of the connecting rod with respect to the piston, the receiving plate of the connecting rod, the crown portion, and The rotation of the piston around the central axis can be prevented without hindering the adjustment of the clearance between the presser foot and the piston. Therefore, the displacement between the combustion chamber and the fuel injection nozzle, the collision between the piston crown surface and the intake / exhaust valve, the inlet of the oil sump that cools the piston crown, and the oil that occur with the rotation of the piston around the central axis Problems such as misalignment with the jet are solved.

[Brief description of drawings]

FIG. 1 is a front sectional view showing a connecting structure of a piston and a connecting rod according to a first embodiment of the present invention.

FIG. 2 is a front sectional view showing a main part of a connecting structure of a piston and a connecting rod according to a second embodiment of the present invention.

[Explanation of symbols]

 2: Piston 2a: Crown part 2b: Skirt part 15: Spherical convex part 15a: Groove 16: Receiving plate 17: Spherical concave part 18: Spherical convex part 21: Connecting rod 23: Presser 24: Spherical concave part 24a: Groove 29: Sphere 31 : Sphere 32: Groove 44: Sphere

Claims (2)

[Claims] 1. A spherical convex portion formed on the lower surface of the piston crown portion is in sliding contact with a spherical concave portion of the receiving plate formed at the tip of the connecting rod, and is in spherical contact with the spherical convex portion of the lower surface of the receiving plate. An annular presser having a recess is fitted and supported on the skirt, and a sphere that is connected to one of the spherical convex part of the receiving plate and the spherical concave part of the presser is engaged with a groove in the meridian direction provided on the other side of the presser. A connecting structure for a piston and a connecting rod, characterized in that a ball connected to one of the outer peripheral surface and the inner surface of the skirt is engaged with an axial groove provided in the other. 2. A spherical surface formed by sliding a spherical concave portion of a receiving plate formed at a tip portion of the connecting rod into sliding contact with a spherical convex portion formed on a lower surface of the piston crown portion, and slidingly contacting a spherical convex portion on a lower surface of the receiving plate. An annular presser having a concave portion is fitted and supported on the skirt portion, and a sphere coupled to one of the spherical convex portion of the piston crown portion and the spherical concave portion of the receiving plate is engaged with a groove in the meridian direction provided on the other. The characteristic connecting structure of the piston and connecting rod.