JPH0131027B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piston device for an internal combustion engine, and more particularly to a piston device for an internal combustion engine in which the structure of a joint between a piston and a connecting rod is improved.

Conventionally, a piston and a connecting rod connected to a crankshaft have been joined to a highly hard piston pin via a piston pin bearing. That is, a mutual joining structure was adopted between the piston skirt made of aluminum alloy at the lower part of the piston, the piston pin, and the piston pin and a connecting rod having a bearing.

On the other hand, it is necessary to increase the output of internal combustion engines, and piston skirts and piston pins that can withstand high loads are required, but with the conventional structure, the bearing area is limited, so it is inevitable to increase the output. The drawback was that there were limitations.

The present invention was made in order to eliminate the above-mentioned drawbacks of the conventional piston, and increases the bearing area by connecting the piston and connecting rod with a spherical block and a spherical bearing part, thereby increasing the output of an internal combustion engine. It is an object of the present invention to provide a piston device for an internal combustion engine configured to realize the following.

Furthermore, the lubrication effect and cooling effect within the piston are improved.

To this end, in the present invention, a spherical block separate from the connecting rod is attached to the end of the connecting rod, and this spherical block is attached to a spherical receiving part on the inner surface of a piston skirt having a piston crown on the head. Two parallel contact surfaces are provided between the lower outer surface of the block and the lower inner surface of the piston, and the spherical block is rotatable only in the direction perpendicular to the crankshaft within the spherical receiving portion, and the connecting rod and the spherical block are An oil hole communicating with each other is provided at each axial center of the piston skirt, and a lateral passage communicating with the oil hole is provided between the piston skirt and the piston crown from the axial center to the vicinity of the outer periphery. A plurality of vertical passages are provided in the vicinity of the piston ring groove, the upper end of which communicates with the horizontal passage, and the lower side of which communicates with the central part of the spherical receiving part and below the central part.

Hereinafter, the present invention will be explained in detail based on embodiments shown in the drawings.

FIG. 1 explains one embodiment of the piston device according to the present invention. In the figure, the reference numeral 1 indicates a piston, and a disk-shaped piston crown 2 is attached to the upper end of the piston. The piston crown 2 is made of a material with low thermal conductivity, such as ceramic.

3 is a cylindrical piston skirt made of cast aluminum or the like, and is connected to the piston crown 2 by tapered bushes 4 and bolts 5 made of heat-resistant steel plates provided at several locations in the circumferential direction. The piston crown 2
It is connected by a cylindrical bolt 7 to a heat-resistant steel member 6 embedded in the central lower part of the body. 3a is a piston ring groove, and the piston ring groove 3a is provided in the piston skirt 3 directly or indirectly via a fitting member 3b.

Reference numeral 8 denotes a connecting rod, the lower end of which is connected to a crankshaft (not shown), and the upper end of the connecting rod 8 has a spherical block 10 fixed thereto, which fits into a spherical receiving portion 9 on the inner surface of the piston 1. The spherical block 10 is made of a highly hard material and is fixed to the upper end of the connecting rod 8 by a bolt 11.

A spherical block presser 1 having a spherical receiving portion 12 on the upper inner surface is provided on the inner lower half of the piston skirt 3.
3 is attached by bolts 14, and a spherical block retainer 13 made of aluminum casting, for example, holds the spherical block 10 together with the spherical receiving part 9.

Opposed protrusions 15 are provided on the inside of the lower end of the spherical block presser 13, and the two protrusions 1
The inner surfaces 15a of 5 are formed parallel to each other.
On the other hand, a protrusion 16 that also serves as a flange is formed at the lower end of the spherical block 10.
The left and right side surfaces 16a of 6 are the inner surface 15 of the protrusion 15.
It is in contact with a. Therefore, the connecting rod 8 and the spherical block 10 are arranged in the direction along the inner surface 15a of the protrusion 15 and the side surface 16a of the protrusion 16;
That is, it can freely rotate only in a direction perpendicular to the crankshaft. In order to rotate the spherical block 10 along the inner surface 15a of the protrusion 15, the diameter of the outer cylindrical surface of the protrusion 16 is made somewhat smaller than the diameter of the inner circumferential surface of the spherical block holder 13. put.

When such a structure is adopted, the piston crown 2 always faces the same direction, and in an engine having an intake/exhaust valve, a notch can be provided at the top of the piston crown 2 when the valve is opened, if necessary.

On the other hand, an oil hole 17 is formed in the center of the connecting rod 8, the lower end of which communicates with an oil hole on the crankshaft side, and the upper end of which passes through a spherical block 10 and communicates with the inside of the piston 1.

The lubricating oil that has climbed into the connecting rod 8 from the crankshaft side through the oil hole 17 is discharged from the upper end of the spherical block 10, and a portion of it is applied to the outer peripheral surface of the spherical block 10, the piston skirt 3, and the spherical block presser. An oil film is formed between the spherical receiving portions 9 and 12, which are the inner circumferential surfaces of 13.

On the other hand, most of the remaining lubricating oil passes through horizontal passages 18 and 19 provided in the bolt 7 and a part of the upper surface of the piston skirt 3, cools the lower surface of the piston crown 2, and then flows into the piston skirt 3. The provided passage 20 and the spherical block presser 1
3 through a plurality of longitudinal passages 21 provided on the inner surface thereof to its lower part.

By the way, the structure in which the spherical block 10 is made separate from the connecting rod 8 and connected via the bolt 11 as described above is adopted for the spherical block 10.
This is because considering the case where a high hardness material is required as a material, we took into account that it can be heat treated, and we made it a separate piece to make it easier to process. Therefore, no special material is required for the connecting rod 8, and the same material as before can be used.

As is clear from the above description, the present invention employs a structure in which the piston and connecting rod are connected via a spherical block and a spherical receiver, eliminating the need for a conventional piston or piston metal. , it is possible to obtain a bearing area that is more than twice that of the conventional one, the bearing load is reduced, and the output of the internal combustion engine can be sufficiently increased.

Further, according to the present invention, since the bearing load is reduced, the piston skirt, which was conventionally manufactured by aluminum forging to increase hardness, can be made into an aluminum cast product, reducing manufacturing costs. be able to.

Further, according to the present invention, a spherical block separate from the connecting rod is attached to the end of the connecting rod, and the spherical block is attached to the spherical receiving part on the inner surface of the piston skirt having the piston crown on the head. The block can be of a different material than the connecting rod and piston skirt, and the piston crown can be of a different material than the piston skirt. Therefore, even if the spherical block is made of a material with high hardness or ceramic with a low specific gravity, no special material is required for the connecting rod, and these can be easily processed. In addition, the piston skirt can be made lighter by casting aluminum, and the piston head, which requires heat resistance, can be made of ceramic piston crown, which increases durability and
It is possible to reduce costs, etc.

Furthermore, in the present invention, oil holes communicating with each other are provided in the axial center portions of the connecting rod, the spherical block, and the piston skirt, and the oil holes are provided between the piston skirt and the piston crown between the axial center portion and the vicinity of the outer periphery. A plurality of communicating lateral passages are provided near the piston ring groove of the piston skirt, and the upper ends communicate with the lateral passages and the lower sides communicate with the central part of the spherical receiving part and below this central part. Since a vertical passage is provided, relatively low-temperature lubricating oil can be supplied into the piston from below the connecting rod through these oil holes and passages, cooling the piston and lubricating the spherical receiver inside the piston. can be done efficiently. That is, a portion of the relatively low-temperature lubricating oil that has risen through the oil hole in the connecting rod and the axial center of the spherical block flows down from the upper end of the spherical block along the spherical surface of the spherical block, and flows down to the piston skirt. It is possible to sufficiently lubricate the space between the inner surface of the spherical receiving portion and the inner surface of the spherical receiving portion. On the other hand, most of the remaining relatively low-temperature lubricating oil rises through the oil hole in the axial center of the piston skirt, and from there enters the lateral passage between the top surface of the piston skirt and the piston crown. Then, it moves downward through a plurality of about 10 vertical passages provided near the piston ring groove of the piston skirt. Therefore, the piston crown, piston skirt, piston ring, etc. can be efficiently cooled by the movement of this relatively low-temperature lubricating oil. Therefore, by providing reliable, easy, and efficient lubrication and cooling, it is possible to achieve efficient piston operation and prolong the life of the piston.

Furthermore, in the present invention, two parallel abutting surfaces are provided between the lower outer surface of the spherical block and the lower inner surface of the piston, so that the spherical block can freely rotate only in the direction perpendicular to the crankshaft within the spherical receiver. Because of this, the piston itself does not rotate in the circumferential direction, and only the normal piston ring, which has a diagonal notch in the circumferential direction, rotates appropriately in the circumferential direction as the piston moves up and down. Waru. Therefore,
Lubrication is not concentrated in one place between the outer circumferential surface of the piston ring and the inner circumferential surface of the piston cylinder, and the entire surface of the sliding portion of the piston ring is well lubricated.

[Brief explanation of drawings]

The figure explains one embodiment of the present invention.
The figure is a longitudinal cross-sectional view, and FIG. 2 is a cross-sectional view taken along the - line in FIG. 1. 1...Piston, 2...Piston crown, 3
... Piston skirt, 8 ... Connecting rod, 9, 12
... Spherical receiver, 10 ... Spherical block, 13...
...Spherical block presser, 17...Oil hole.

Claims (1)

[Claims] 1 Attach a spherical block separate from the connecting rod to the end of the connecting rod, attach this spherical block to the spherical receiving part on the inner surface of the piston skirt that has a piston crown on the head, and connect the lower outer surface of the spherical block with the piston. two parallel abutting surfaces are provided between the lower inner surfaces, and the spherical block is rotatably provided within the spherical receiving portion only in a direction perpendicular to the crankshaft;
An oil hole communicating with each other is provided at each axial center of the connecting rod, spherical block, and piston skirt, and a lateral passage communicating with the oil hole is provided between the piston skirt and the piston crown from the axial center to the vicinity of the outer periphery. A plurality of longitudinal passages are provided in the vicinity of the piston ring groove of the piston skirt, the upper end of which communicates with the horizontal passage, and the lower side of which communicates with the central part of the spherical receiving part and below the central part. Piston device of internal combustion engine.