JP2003343724A - Connection structure of piston and connecting rod - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To significantly reduce the bearing on top of a boss hole of a pin boss part in the connection structure of a piston and a connecting rod of an internal combustion engine. <P>SOLUTION: The connection structure comprises the piston, a piston pin, the connecting rod and a connecting means. The piston has the pin boss part formed on the rear side of a piston body and a gap formed on the opposite side of the pin boss part from the piston body. The piston pin inserted into the boss hole formed on the pin boss part has a notch groove between the gaps formed on the pin boss part. The connecting rod has a connecting part on one end side of a rod body to be engaged with the notch groove of the piston pin. The connecting means is for connecting the connecting part to the piston pin. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston-connecting rod connecting structure for connecting a piston and a connecting rod in an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, in an internal combustion engine, when the internal combustion engine is operating, the explosive force acting on the upper surface of the piston acts as a concentrated stress on the upper surface of the boss hole of the pin boss portion of the piston, and the upper surface of the boss hole of the pin boss portion. It has been known that the surface pressure of the product becomes excessive. Further, the piston pin is bent to some extent, and as a result, excessive stress is concentrated on the upper surface of the boss hole of the pin boss portion, which may cause crack damage to the pin boss portion.

FIG. 8 and FIG. 9 show a connecting structure of the piston 1 and the connecting rod 2 in which such problems are reduced. In this connecting structure, the connecting rod 2 of the connecting rod 2 is provided between the pin boss portions 1a of the piston 1. The small end 2a is arranged. Small end 2a of connecting rod 2
Both end faces are inclined with the tip side toward the center, and the width on the tip side is reduced by the inclined surface 2b.

A boss hole 1b formed in the pin boss portion 1a and a mounting hole 2c formed through the small end portion 2a.
And the piston pin 3 indicated by the chain double-dashed line in the figure
The piston 1 and the connecting rod 2 are connected. In such a connecting structure, the connecting rod 2
Since the width of the small end portion 2a of the piston 1 on the tip side is reduced, the length L of the upper surface of the boss hole 1b of the pin boss portion 1a of the piston 1 can be increased, and the pin 1 of the piston 1 can be increased due to the increase of the pressure receiving area. It is possible to reduce the concentration of stress acting on the upper surface of the boss hole 1b of the portion 1a.

Also, the small end 2 of the connecting rod 2
Since the width of the end a of the connecting rod 2 is reduced, the weight of the connecting rod 2 can be reduced.

[0006]

However, in such a conventional connecting structure, the tip 2d of the small end 2a of the connecting rod 2 is the piston body 1 of the piston 1.
Since it projects to the rear surface side of d, the upper surface of the boss hole 1b of the pin boss portion 1a is largely divided by the tip portion 2d, making it difficult to secure a sufficient length of the upper surface of the boss hole 1b of the pin boss portion 1a. Therefore, there is a problem that the surface pressure of the upper surface of the boss hole 1b of the pin boss portion 1a cannot be reduced sufficiently.

The present invention has been made to solve such a conventional problem, and provides a connecting structure for a piston and a connecting rod capable of significantly reducing the surface pressure of the upper surface of the boss hole of the pin boss portion as compared with the prior art. The purpose is to provide.

[0008]

According to a first aspect of the present invention, there is provided a connecting structure of a piston and a connecting rod, wherein a pin boss portion is formed on the back side of the piston body, and a space portion is formed on the side opposite to the piston body of the pin boss portion. A piston, a piston pin fitted into a boss hole formed in the pin boss portion and having a notch groove formed between the space formed in the pin boss portion, and a piston pin on one end side of the rod body. It has a connecting rod in which a connecting part which fits in the notch is formed, and a connecting means which connects the connecting part to the piston pin.

According to a second aspect of the present invention, there is provided a piston-connecting rod connecting structure according to the first aspect, wherein the connecting means is a bolt hole formed on both sides of the rod body in the connecting portion. And a female screw hole formed at a position corresponding to the bolt hole on the bottom surface of the cutout groove of the piston pin, and a bolt inserted into the bolt hole and having a tip screwed into the female screw hole. Is characterized by.

According to a third aspect of the present invention, there is provided a piston-connecting rod connecting structure according to the first aspect, wherein the connecting means includes the piston pin and the connecting portion, and an axial length of the piston pin. It has a pin hole formed in the direction and a pin member fitted and inserted in the pin hole.

(Operation) In the connecting structure of the piston and the connecting rod according to the first aspect, the piston pin is first inserted into the boss hole formed in the pin boss portion on the back side of the piston body. Next, the connecting portion formed on one end side of the rod body of the connecting rod is fitted into the notch groove of the piston pin.

The connecting portion connects the connecting portion of the connecting rod to the piston pin. Therefore,
It is possible to continuously form the upper surface of the boss hole over the entire length of the pin boss portion formed on the back side of the piston body, and it is possible to secure a sufficient length of the upper surface of the boss hole of the pin boss portion. Become.

In the connecting structure of the piston and the connecting rod according to claim 2, bolts are inserted into the bolt holes formed on both sides of the rod body in the connecting portion, and the tips of the bolts are attached to the bottom of the notch groove of the piston pin. The connecting portion of the connecting rod is fixed to the notch groove of the piston pin by being screwed into the female screw hole formed at the position corresponding to.

In the connecting structure of the piston and the connecting rod according to the third aspect of the present invention, the connecting portion of the connecting rod is connected to the piston pin by inserting the pin member into the pin hole formed in the axial direction of the piston pin and the connecting portion. It is fixed in the notch groove.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention shown in the drawings will be described.

(First Embodiment) FIG. 1 shows a first embodiment of a connecting structure for a piston and a connecting rod according to the present invention.

In FIG. 1, reference numeral 11 indicates a piston. As shown in FIG. 2, the piston 11 is formed by integrally forming a pin boss portion 15 on the back surface of the piston body 13. A boss hole 15a is formed through the pin boss portion 15 on the same axis. Pin boss 15
Is formed such that the upper half of the boss hole 15a is continuous.

The lower center of the pin boss 15 is cut out in a rectangular shape to form a space 15b. The boss hole 15a of the pin boss portion 15 has a cylindrical piston pin 1
7 is inserted. The piston pin 17 has a notch groove 17 at a position corresponding to the space 15b of the pin boss 15.
a is formed.

In the notch groove 17a, the connecting portion 1 formed at one end of the rod body 19a of the connecting rod 19 is formed.
9b is fitted. As shown in FIGS. 3 and 4, the connecting portion 19b has a shape corresponding to the cutout groove 17a of the piston pin 17. A rod body 19a of the connecting rod 19 is integrally formed at the center of the connecting portion 19b.

The connecting portion 19b is fixed to the cutout groove 17a of the piston pin 17 by the connecting means 21. In this embodiment, a pair of bolt holes 19c are formed at positions on both sides of the rod body 19a in the connecting portion 19b. In addition, the notch groove 17 of the piston pin 17
Female screw holes 17b are formed at positions corresponding to the bolt holes 19c on the bottom surface of a.

The connecting portion 19b is fixed to the piston pin 17 by inserting the bolt 23 into the bolt hole 19c and screwing the tip of the bolt 23 into the female screw hole 17b. In the connection structure of the piston 11 and the connecting rod 19 described above, first, the piston pin 17 is inserted into the boss hole 15a formed in the pin boss portion 15 on the back side of the piston body 13.

Next, the notch groove 17a of the piston pin 17
A connecting portion 19b formed on one end side of the rod body 19a of the connecting rod 19 is fitted in. And
By inserting the bolt 23 into the bolt hole 19c and screwing the tip of the bolt 23 into the female screw hole 17b, the connecting portion 19
b is fixed to the piston pin 17. In the connection structure of the piston 11 and the connecting rod 19 described above, the piston pin 17 is fitted and inserted into the boss hole 15a formed in the pin boss portion 15 on the back side of the piston body 13.
The connecting portion 19b formed on one end side of the rod body 19a of the connecting rod 19 is fitted into the cutout groove 17a of 7, and the connecting portion 19b of the connecting rod 19 is connected to the piston pin 17 by the bolt 23. Therefore, it becomes possible to continuously form the upper surface of the boss hole 15a over the entire length of the pin boss portion 15.
The surface pressure on the upper surface of the boss hole 15a can be significantly reduced as compared with the conventional case.

That is, in the connection structure of the piston 11 and the connecting rod 19 described above, the piston pin 17
Since the connecting portion 19b of the connecting rod 19 is connected to the notch groove 17a of the connecting rod 19, the tip end of the small end portion of the connecting rod does not project to the rear surface side of the piston body of the piston as in the conventional case. The upper surface of the boss hole of the pin boss portion is not largely divided by the tip portion, and the upper surface of the boss hole 15a can be continuously formed over the entire length of the pin boss portion 15 formed on the back side of the piston body 13. Enabled, boss hole 1 of pin boss 15
A sufficient length of the upper surface of 5a can be secured.

As a result, it becomes possible to sufficiently cope with the increase in the combustion pressure as the engine output increases.
Further, since it becomes possible to continuously form the upper surface of the boss hole 15a over the entire length of the pin boss portion 15, it is possible to reduce the bending deformation amount of the piston pin 17.
The stress generated on the upper surface of the boss hole 15a can be relaxed.

In the connecting structure of the piston 11 and the connecting rod 19 described above, the bolt holes 19c formed on both sides of the rod body 19a in the connecting portion 19b.
The connecting rod 19 is connected by inserting the bolt 23 into the screw and screwing the tip of the bolt 23 into the female screw hole 17b formed at the position corresponding to the bolt hole 19c on the bottom surface of the notch groove 17a of the piston pin 17. Since the portion 19b is fixed to the cutout groove 17a of the piston pin 17, the connecting portion 19b of the connecting rod 19 can be firmly fixed to the cutout groove 17a of the piston pin 17.

(Second Embodiment) FIGS. 5 to 7 show details of essential parts of a second embodiment of the connecting structure of the piston 11 and the connecting rod 19 of the present invention. In this embodiment, the connecting portion 19b between the piston pin 17 and the connecting rod 19 is connected by the pin member 25.

That is, the piston pin 17 is formed with a pin hole 17c in the axial direction. This pin hole 17c
Is formed at a position crossing the cutout groove 17a of the piston pin 17. A pin hole 19d is formed in the connecting portion 19b of the connecting rod 19 at a position corresponding to the pin hole 17c of the piston pin 17.

The notch groove 17a of the piston pin 17
With the connecting portion 19b of the connecting rod 19 fitted in, the pin member 25 is inserted into the pin holes 17c and 19d, whereby the connecting portion 1 of the connecting rod 19 is inserted.
9b is fixed in the notch groove 17a of the piston pin 17.

In this embodiment, the same members as those in the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted. In the connecting structure of the piston 11 and the connecting rod 19 of this embodiment, the pin holes 17c, 1 formed in the axial direction of the piston pin 17 and the connecting portion 19b.
Since the connecting portion 19b of the connecting rod 19 is fixed to the cutout groove 17a of the piston pin 17 by inserting the pin member 25 into 9d, the connecting portion 19b of the connecting rod 19 is cut into the cutout groove of the piston pin 17. It can be easily fixed to 17a.

[0030]

As described above, in the connecting structure of the piston and the connecting rod according to the first aspect, the piston pin is fitted into the boss hole formed in the pin boss portion on the back side of the piston body, and the notch groove of the piston pin is inserted. , The connecting portion formed on one end side of the rod body of the connecting rod is fitted, and the connecting portion is configured to connect the connecting portion of the connecting rod to the piston pin, so that the boss hole is formed over the entire length of the pin boss portion. The upper surface can be continuously formed, and the surface pressure on the upper surface of the boss hole of the pin boss portion can be significantly reduced as compared with the conventional case.

In the connecting structure of the piston and the connecting rod of claim 2, bolts are inserted into the bolt holes formed on both sides of the rod body in the connecting portion, and the tips of the bolts are attached to the bottom of the notch groove of the piston pin. By connecting the connecting part of the connecting rod to the notch groove of the piston pin by screwing it into the female screw hole formed at the position corresponding to, the connecting part of the connecting rod is firmly attached to the notch groove of the piston pin. Can be fixed to.

According to the third aspect of the present invention, in the connecting structure of the piston and the connecting rod, the connecting portion of the connecting rod is connected to the piston pin by inserting the pin member into the pin hole formed in the axial direction of the piston pin and the connecting portion. The connecting portion of the connecting rod can be easily fixed to the notch groove of the piston pin because it is fixed to the notch groove.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view showing the piston of FIG.

3 is a cross-sectional view showing details of a connecting structure between the piston pin and the connecting portion of FIG.

FIG. 4 is an exploded perspective view showing details of a connecting structure between the piston pin and the connecting portion of FIG.

FIG. 5 is an exploded perspective view showing a main part of a second embodiment of the connecting structure of the piston and the connecting rod of the present invention.

6 is a side view showing a connecting structure of the piston pin and the connecting portion of FIG.

FIG. 7 is a front view showing a connecting structure between the piston pin and the connecting portion of FIG.

FIG. 8 is a front view showing a conventional connecting structure of a piston and a connecting rod.

9 is a cross-sectional view showing the connection structure of FIG.

[Explanation of symbols]

11 pistons 13 Piston body 15 pin boss 15a Boss hole 15b space section 17 piston pin 17a Notch groove 17b Female screw hole 17c pin hole 19 connecting rod 19a Rod body 19b connection part 19c bolt hole 19d pin hole 21 Connection means 23 Volts 25 pin member

Claims (3)

[Claims] 1. A piston in which a pin boss portion is formed on the back side of the piston body and a space portion is formed on the side opposite to the piston body of the pin boss portion, and the piston is fitted into a boss hole formed in the pin boss portion, A piston pin in which a cutout groove is formed between the space portions formed in the pin boss portion; and a connecting rod in which a connecting portion that is fitted into the cutout groove of the piston pin is formed at one end side of the rod body. Connecting means for connecting the connecting portion to the piston pin,
A connecting structure between a piston and a connecting rod, characterized in that 2. The connecting structure of a piston and a connecting rod according to claim 1, wherein the connecting means includes bolt holes formed on both sides of the rod body in the connecting portion, and a bottom surface of the cutout groove of the piston pin. A female screw hole formed at a position corresponding to the bolt hole, and a bolt inserted into the bolt hole and having a tip screwed into the female screw hole, the piston and the connecting rod are connected. Construction. 3. The connecting structure for connecting a piston and a connecting rod according to claim 1, wherein the connecting means includes a pin hole formed in the piston pin and the connecting portion in an axial direction of the piston pin, and the pin. A connecting member for connecting a piston and a connecting rod, comprising: a pin member fitted into the hole.