JPH05280641A - Piston device for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide a piston device for an internal combustion engine wherein a location of connecting a piston to a connecting rod can be formed small in size and light in weight. CONSTITUTION:A piston pin part 3 extended in a right angle direction relating to a connecting rod axial line L is integrally formed in one end of a steel-made connecting rod 2, a half-split pin receiving part 10 with the piston pin part 3 swivelably into slide contact is formed in the central part of a back surface 9 of a light metal-made piston 1, caps 11, 11 of presenting a half split shape are arranged with a space in both ends 10a of the pin receiving part 10, and a connecting location 14 for swivelably supporting the piston pin part 3 is constitute of these parts and caps.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston device for an internal combustion engine which comprises a piston and a connecting rod connected to the piston.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 6, a piston pin 53 is inserted into a pin boss portion 52 formed on a piston 51, and the piston pin 53 and a connecting rod 54 are fastened together with a bolt 55, so that the piston pin 53 as a whole. There is known a piston device for an internal combustion engine which receives a combustion pressure (see JP-A-61-244967, etc.).

[0003]

However, in such a conventional piston device, a connecting portion 56 by a bolt 55 is provided between the connecting rod 54 and the piston pin 53, and the piston pin 53 is also provided. Is a large notch 5 with which the connecting rod 54 is butted.
7 is formed, the piston pin 53 must have a large diameter and a large weight in order to provide the connecting portion 56 with strength and rigidity that can withstand the combustion pressure due to the explosion and the inertial force due to the reciprocating motion in the cylinder. Inevitably, the compression height (distance from the crown surface of the piston to the center of the piston pin) becomes large, and the size and weight of the entire piston cannot be reduced.

The present invention has been made in view of such problems, and it is possible to reduce the size and weight of the connecting portion while providing the connecting portion between the piston and the connecting rod with necessary strength and rigidity. It is intended to provide a piston device for an internal combustion engine.

[0005]

In order to solve the above-mentioned problems, the present invention integrally forms a piston pin portion extending in a direction perpendicular to the axis of the connecting rod at one end of the connecting rod, and An articulated piston consisting of a pair of pin bosses that swingably support both ends of the piston pin and a half-divided pin receiving portion that slides on the piston pin between the pin bosses at the center of the back surface of the alloy piston. And forming at least one of the pin boss portions into a half-divided shape and detachably fastened.

[0006]

[Operation] It is necessary to secure a pressure receiving area between the piston and the piston pin portion, which can withstand the inertial force due to the reciprocating motion in the cylinder and the combustion pressure due to the explosion. Since the combustion pressure is received by the entire portion, the total length of the piston pin portion can be shortened and the connecting portion can be made compact.

In addition, since the piston pin portion is formed integrally with the connecting rod, it is possible to reduce the diameter of the piston pin portion while providing the necessary strength and rigidity. As a result, the distance from the crown surface of the piston to the center of the piston pin (compression height) can be kept small, and the overall size and weight of the piston can be reduced.

Moreover, since the pin boss made of light alloy is formed in half to give it the necessary strength and rigidity, it has the necessary strength at the connecting portion between the piston pin and the connecting rod as in the conventional example. The effect of weight reduction is remarkable as compared with the case of using the same.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. 2 is a sectional view taken along the line AA of FIG.
FIG. 3 is a BB arrow view of FIG. 1 excluding the connecting rod 2.

Reference numeral 1 denotes a light alloy piston which reciprocates in a cylinder (not shown), and 2 denotes a steel connecting rod. One end of the connecting rod 2 is connected to the piston 1, and the other end (not shown) is connected to the crankshaft (not shown).

A piston pin portion 3 extending in a direction perpendicular to the axis L of the connecting rod 2 is integrally formed at one end of the connecting rod 2, and the piston pin portion 3 has a hollow cylindrical shape and reciprocating inertia. It contributes to weight reduction.

Compression ring grooves 5 and 6 and an oil ring groove 7 are circumferentially formed near the piston crown surface 4 on the outer peripheral surface of the piston 1, and a compression ring (not shown) and an oil ring (not shown) are formed in these grooves. (Omitted) is housed respectively.

Skirts 8 are formed on the outer peripheral surface of the piston 1 in the swinging direction of the connecting rod 2, that is, on the thrust / anti-thrust side, and other portions are greatly cut out to a position immediately below the oil ring groove 7. Is becoming

A half-divided pin receiving portion 10 on which the piston pin portion 3 is slidably slidably formed is formed at the center of the rear surface 9 of the piston, and the axial length thereof is the same as that of the piston pin portion 3. It is formed to have almost the same length.

At both ends 10a of the pin receiving portion 10, a pair of half-capped caps 11, 11 are arranged with a space therebetween, and each cap 11, 11 has two bolts 12 respectively.
Is removably fastened. That is, the cap 11 is fastened to the pin receiving portion 10 to form a pair of pin boss portions 13, and the pin boss portions 13 swingably support both ends of the piston pin portion 3 and are located between the pin boss portions 13. Reference numeral 10b is in sliding contact with the piston pin portion 3 and constitutes a connecting portion 14 for swingably supporting the piston pin portion 3.

The back surface 1 of both ends 10a of the pin receiving portion 10
5, ribs 16 are formed extending from the bottom surface 9 of the piston 8 to the lower edge 8a of the skirt 8. The shape of the rib 16 is curved outward as shown in FIG. 3, thereby complementing the strength of the connecting portion 14.

Therefore, between the cap 11 and the piston pin portion 3, a sufficient pressure receiving area that can withstand the inertial force acting when the piston 1 reciprocates in the cylinder is secured, and at the same time, the piston pin portion 3 and A sufficient pressure receiving area that can withstand the combustion pressure associated with combustion is secured between the pin receiving portion 10 and the pin receiving portion 10.

Next, the operation will be described based on such a configuration.

Between the piston 1 and the piston pin portion 3, an inertial force caused by the reciprocation of the piston 1 in the cylinder and a combustion pressure caused by combustion act. Generally, the combustion pressure is twice as much as the inertial force. Big to the extent. That is, it is necessary to secure a sufficient pressure receiving area between the piston pin portion 3 and the pin receiving portion 10 so as to withstand the combustion pressure. Since the piston pin portion 3 is configured to be received, the total length of the piston pin portion 3 can be shortened to the minimum, and the periphery of the connecting portion 14 can be made compact.

In addition, since there is no connecting portion between the piston pin portion 3 and the connecting rod 2 as in the conventional example, the piston pin portion 3 can be made smaller and lighter, and especially the diameter of the piston pin portion 3 can be made smaller. Thus, the compression height H formed between the piston crown surface 4 and the center of the piston pin portion 3 can be suppressed to a small value.

Moreover, since the pin boss portion 13 made of light alloy is formed in half and given necessary strength, the strength required for the connecting portion between the steel piston pin and the connecting rod is provided as in the conventional example. The effect of weight reduction is more remarkable than having it. Thus, the cap 11 has a small amount of extra meat to give it strength and rigidity, but the size and weight of the piston 1 as a whole can be reduced.

Next, a second embodiment of the present invention will be described with reference to FIG.

This embodiment is applied to a two-ring piston in which one compression ring and one oil ring are inserted.

That is, on the outer peripheral surface of the piston 21, a compression ring groove 23 is formed near the piston crown surface 22, and one oil ring groove 24 is formed at a distance from the compression ring groove 23, and these two grooves are formed in these two grooves. A compression ring (not shown) and an oil ring (not shown) are housed therein. Other configurations are first
According to the embodiment, the same numbers are given and the description thereof is omitted.

Based on such a construction, the diameter of the piston pin portion 3 can be reduced as in the first embodiment, and the compression height H formed between the piston crown surface 22 and the center of the piston pin portion 3 can be kept small. Obviously, the piston ring (compression ring, oil ring) can be accommodated in a much thinner width than the one that accommodates three piston rings. Can be connected part 14
In addition to the downsizing, the size and weight of the piston 21 as a whole are significantly reduced.

Next, a third embodiment of the present invention will be described with reference to FIG.

Connecting rod 31 according to the present embodiment
Is the one in which the piston pin portion 32 formed separately is coupled and integrated by the liquid phase diffusion bonding method, and other configurations are the same as those in the first embodiment, and the description thereof will be omitted.

Based on such a configuration, the piston pin portion 32 formed at one end of the connecting rod 31 is completely fixed and integrated by liquid phase diffusion bonding, so that the piston is small and lightweight as in the first embodiment. Is achieved. Moreover, the piston pin portion 32 is connected to the connecting rod 31.
By being formed as a separate body, the degree of freedom in design is improved.

In each of the above embodiments, the pair of caps 11 and 11 are both fastened to the pin receiving portion 10 with the bolts 12, but the present invention is not limited to this, and at least one of the caps 11 is a pin. It may be formed integrally with the receiving portion 10.

[0030]

As described above, according to the present invention, since the entire piston pin portion receives the combustion pressure, the total length of the piston pin portion can be shortened and the connecting portion can be made compact. ..

In addition, since the piston pin portion is formed integrally with the connecting rod, the diameter of the piston pin portion can be reduced, and the distance (compression height) from the piston crown surface to the center of the piston pin portion can be reduced. It can be made small, and the pin boss made of light alloy is split in half to give it the necessary strength and rigidity, so it is necessary for the connecting part between the piston pin and the connecting rod as in the conventional example. The effect of weight reduction is remarkable as compared with the one with strength, and the overall size and weight of the piston can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a piston according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a view taken along the line BB of FIG.

FIG. 4 is a vertical sectional view of a piston according to a second embodiment of the present invention.

FIG. 5 is a vertical sectional view of a connecting rod according to a third embodiment of the present invention.

FIG. 6 is a diagram showing a conventional piston device.

[Explanation of symbols]

 1 Piston 2 Connecting rod 3 Piston pin part 10 Pin receiving part 11 Cap 12 Bolt 13 Pin boss part 14 Connecting part L axis

Claims (1)

[Claims] 1. A piston pin portion extending in a direction perpendicular to the axis of the connecting rod is integrally formed at one end of the connecting rod, and both ends of the piston pin portion are shaken at the central portion of the rear surface of the light alloy piston. A connecting portion composed of a pair of movably supported pin boss portions and a half-divided pin receiving portion slidingly contacting the piston pin portion between the pin boss portions is formed, and at least one of the pin boss portions is half-divided. Be removably fastened,
A piston device for an internal combustion engine, which is characterized in that: