JPH0749830B2 - 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 holding cylinder screwed to a skirt for holding a presser for properly maintaining the gap between the connecting plate of the connecting rod and the connecting portion of the piston. The present invention relates to a connecting structure of a piston and a connecting rod that supports and locks a holding cylinder at an appropriate adjustment position so as not to loosen it.

[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.

In the above-described connecting structure of the piston and the connecting rod,
The spherical concave portion of the presser supported on the skirt is slidably supported by the spherical convex portion of the lower surface of the receiving plate that is integral with the tip of the connecting rod, and the spherical convex portion of the piston crown slides on the spherical concave portion of the receiving plate. It is supported so that it can touch. The gap between the spherical concave portion of the presser foot and the spherical convex portion of the receiving plate, and the clearance between the spherical concave portion of the receiving plate and the spherical convex portion of the piston crown part are It is adjusted according to the screwing amount.

[0004]

However, in order to prevent the retaining cylinder from slipping out, it is only held down by the ordinary retaining ring engaged with the annular groove on the inner surface of the skirt portion, so the above-mentioned clearance of the sliding contact portion is adjusted. However, if there is a gap between the holding cylinder and the retaining ring, there is a problem that the holding cylinder is loosened and the gap of the sliding contact portion changes.

In view of the above problems, an object of the present invention is to maintain a proper gap between the connecting plate of the connecting rod and the piston.
It is an object of the present invention to provide a connecting structure of a piston and a connecting rod that can hold a holding cylinder that supports a presser foot at an adjustment position regardless of how much the skirt portion is screwed.

[0006]

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. An annular presser having a spherical recess that is slidably contacted with the lower surface of the receiving plate is supported on the holding surface of a stepped holding cylinder screwed to the skirt, and screwed to the skirt to form a holding cylinder. A retaining ring whose lower end has a conical surface is elastically engaged between the lower end surface of the abutting lock screw and the conical surface of the annular groove provided in the skirt portion.

[0007]

The lower surface of the annular groove provided on the inner surface of the skirt portion of the piston is a conical surface that inclines downward toward the axial center, and the lower end of the retaining ring is also a conical surface. Therefore, the holding cylinder is screwed into the screw hole of the skirt, and the gap between the spherical concave portion of the presser and the spherical convex portion of the receiving plate and the gap between the spherical concave portion of the receiving plate and the spherical convex portion of the piston crown portion are set. After adjusting properly, screw the lock screw into the screw hole of the skirt, and engage the snap ring with the annular groove on the inner surface of the skirt.The snap ring elastically expands, and the upper end surface of the snap ring is locked by the lock screw. Of the retaining ring, and the conical surface of the lower end of the retaining ring overlaps the conical surface of the annular groove. The locking screw and the holding cylinder are held in the adjustment position by the wedge action of the retaining ring, and do not loosen.

[0008]

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. In order to reduce the weight and heat load of the crown portion 2a, the crown portion 2a is provided with an empty portion 8 from the lower surface 7 and is closed by a lid 8a.

In order to effectively cool the periphery of the combustion chamber 4 with oil, an annular oil reservoir 5 is formed so as to surround the lower protruding portion of the crown portion 2a. The oil sump 5 is defined by fitting an annular partition plate 6 into the cylindrical portion 2c of the crown portion 2a. 180 on partition 6
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 are provided with different phases of °.

A sliding body 9 having a spherical convex portion 15 is slidably engaged with the lower surface 7 of the crown portion 2a. On the flat upper surface of the slide body 9, an axial passage 13 and an annular groove 12 for lubrication are provided.
And are formed. A plurality of groove passages 34 that connect the groove 12 and the passage 13 are provided on the upper surface of the sliding body 9. A plurality of passages 10 extending from the outer peripheral surface to the grooves 12 inside the sliding body 9;
And a plurality of passages 14 extending from the spherical projection 15 to the spherical convex portion 15. The lower half of the passage 13 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 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.

For 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 presser foot 23 is fitted with a sleeve 22 having an inverted L-shaped cross section. The presser foot 23 is loosely fitted to the inside of the holding cylinder 26 and its movement in the radial direction is restricted, and the lower end surface of the presser foot 23 is screwed into the screw hole of the skirt portion 2b. Supported by 25.

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 fitted on the presser foot 23 is engaged with a hole in the upper end surface of the presser foot 23. The sphere 31 coupled to the outer peripheral surface of the sleeve 22 forms the skirt portion 2
It is engaged with an axial groove 32 provided on the inner surface of b.

An inlet passage 33 extending toward the inlet 6a of the partition plate 6 is provided in the presser 23, and oil is jetted toward the inlet passage 33 from an oil jet arranged at the lower end of a cylinder (not shown). It The oil jetted from the oil jet flows into the oil reservoir 5 through the inlet passage 33 and the inlet 6a of the partition plate 6, where it is divided into two parts and half-circulates the oil reservoir 5 in the opposite direction, and the crown portion 2a of the piston 2 To the outlet 6b on the opposite side
Flows out into the space below the partition plate 6.

The oil in the empty space below the partition plate 6 flows into the groove 12 through the passage 10, and the oil in the groove 12 flows in the groove passage 34 in the sliding member 9.
The sliding contact portion between the crown portion 2a and the crown portion 2a is lubricated to flow to the passages 13 and 19, and the sliding contact portion between the spherical concave portion 17 and the spherical convex portion 15 is lubricated from the passage 14 to flow to 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 lower empty space of the partition plate 6 is not limited to the spherical concave portion 24 of the presser 23 and the spherical convex portion 18 of the receiving plate 16.
Lubricate the sliding contact part with.

As shown in FIG. 2, according to the present invention, in order to prevent the holding cylinder 26 from loosening, an annular groove 28 for locking the retaining ring 27 is provided on the inner surface of the skirt portion 2b. A conical surface 28a is formed on the side wall of the. The holding cylinder 26 is screwed into the screw hole of the skirt portion 2a to receive the connecting plate 21 of the connecting rod 21.
After adjusting the clearance between the connecting portion of the piston 6 and the piston 2, the lock screw 45 is screwed into the screw hole of the skirt portion 2a, and the retaining ring is provided between the lower end surface of the lock screw 45 and the conical surface 28a of the annular groove 28. 27 engages. The retaining ring 27 is elastically expanded and deformed so that the conical surface 27a at the lower end engages with the conical surface 28a of the annular groove 28, so that the retaining tube 26 and the locking screw 45 are screwed together regardless of how much they are screwed in. Prevent loosening of the lock screw 45. The load applied from the receiving plate 16 to the presser 23 is supported by the holding cylinder 26, the screwing portion of the lock screw 45, and the locking portion of the retaining ring 27 with respect to the skirt portion 2a.

In the embodiment described above, the sliding body 9 having the spherical convex portion 15 is slidably contacted with the lower surface 7 of the crown portion 2a of the piston 2, but they may be integrally formed.

[0018]

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 to slide on the lower surface of the receiving plate. An annular presser having a spherical recess in contact with it is supported on the holding surface of a stepped holding cylinder screwed into the skirt portion, and the lower end surface of the lock screw screwed into the skirt portion and brought into contact with the holding cylinder. Since the retaining ring whose lower end has a conical surface is elastically engaged with the conical surface of the annular groove provided in the skirt portion, the holding cylinder supporting the presser foot is irrespective of the screwed amount into the skirt portion. , Locked at the adjusting position by the lock screw and the snap ring, the gap between the connecting plate of the connecting rod and the piston is properly maintained.

Since the holding cylinder and the lock screw are screwed into the screw holes on the inner surface of the skirt portion, the rigidity integral with the holding cylinder of the skirt portion is ensured, and the engagement between the presser foot and the skirt portion is ensured. The reliability with respect to the looseness of the presser foot is enhanced.

The load that the holding cylinder receives from the presser is only the inertial force of the piston, and in the case of the conventional piston pin connection structure, the load is lighter than that of the piston pin that receives repeated bending loads, and durability is improved. Excellent reliability.

Since the presser foot is supported by the holding surface of the holding cylinder,
When the connecting rod swings, the presser can slightly slide in the radial direction against the lateral impact load when the piston outer peripheral surface collides with the cylinder inner wall, and the piston slides on the cylinder inner wall with the vertically long outer peripheral surface. Therefore, the impact load is alleviated and the collision noise is also reduced.

[Brief description of drawings]

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

FIG. 2 is a front cross-sectional view showing an enlarged main part of the same structure.

[Explanation of symbols]

 2: Piston 2a: Crown 2b: Skirt 15: Spherical convex 16: Receiving plate 17: Spherical concave 21: Connecting rod 23: Presser 24: Spherical concave 25: Holding surface 26: Holding cylinder 27: Retaining ring 27a: Conical Surface 28: Annular groove 28a: Conical surface 45: Lock screw

Claims (1)

[Claims] 1. An annular shape having a spherical concave portion formed on the lower surface of the piston crown, a spherical concave portion of a receiving plate formed on the tip of the connecting rod being slidably in contact with the spherical concave portion of the lower surface of the receiving plate. Of the lock screw supported by the holding surface of the stepped holding cylinder screwed to the skirt, and screwed into the skirt to abut the holding cylinder and the annular groove formed in the skirt. A connecting structure of a piston and a connecting rod, characterized in that a retaining ring whose lower end has a conical surface is elastically engaged with the conical surface.