JPH0972418A - Piston pin for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piston pin for an internal combustion engine capable of improving wearing resistance without increasing manufacturing costs. SOLUTION: A piston pin main body 1a is formed of a metallic cylindrical material, a solid lubricating agent layer 2 is formed in the peripheral surface of this piston pin main body 1a and a recessed part 6 for holding lubricating oil is formed in a part of the outer peripheral surface in which this solid lubricating agent layer 2 is formed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a piston pin used for a piston for an internal combustion engine.

[0002]

2. Description of the Related Art Generally, a piston pin used in a piston for an internal combustion engine is inserted into a piston pin hole formed in a piston body and is press-fitted into a small end hole formed at one end of a connecting rod to form a piston body. And the connecting rod. The other end of the connecting rod is connected to the crankshaft to rotate the crankshaft by the reciprocating motion of the piston.At this time, the piston pin rotates with respect to the piston pin hole, causing friction between the piston pin and the piston pin hole. Occurs. Therefore, it is necessary to improve the wear resistance of the piston pin.

Conventionally, as this type of piston pin, there is one described in Japanese Utility Model Laid-Open No. 3-56851. This piston pin is formed by forming a piston pin body with a metal cylindrical material, and coating the entire circumferential surface of this piston pin body with a solid lubricant. The friction with the pin hole is reduced and the wear resistance of the piston pin is improved.

Further, in the conventional example disclosed in Japanese Utility Model Laid-Open No. 59-19160, a high-rigidity carbon fiber is lapped and a resin is impregnated between the high-rigidity carbon fiber to form a cylindrical piston pin. ing. In this conventional example, the high-rigidity carbon fiber used as the material itself has excellent lubricity, and the surface of the piston pin has high lubricity retention and wear resistance due to the irregularities of the high-rigidity carbon fiber. It has become a thing.

[0005]

However, in the conventional example described in Japanese Utility Model Laid-Open No. 3-56851, since the solid lubricant layer is formed on the entire peripheral surface, the lubricating oil retaining ability on the solid lubricant is high. However, the lubricating performance of the lubricating oil was not fully utilized, and there was a risk of causing high friction between the piston pin and the piston pin hole.

Further, in the conventional example described in Japanese Utility Model Laid-Open No. 59-19160, the manufacturing cost of the piston pin made of high-rigidity carbon fiber is high although the lubricating oil holding capacity is increased.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a piston pin for an internal combustion engine capable of improving wear resistance without increasing manufacturing cost. To do.

[0008]

In order to achieve the above object, in a piston pin for an internal combustion engine according to the present invention, a piston pin main body is formed of a cylindrical member made of metal, and a peripheral surface of the piston pin main body is In a piston pin for an internal combustion engine configured by forming a solid lubricant layer, a recess for retaining lubricating oil is formed in a part of the outer peripheral surface on which the solid lubricant layer is formed. As a solid lubricant, molybdenum disulfide,
A fluorine-based synthetic resin or the like can be applied. The solid lubricating layer is formed by coating, screen printing or the like.

With this structure, in the internal combustion engine piston pin according to the present invention, when the internal combustion engine piston pin is inserted into the piston pin hole, the solid lubricant layer comes into contact with the inner surface of the piston pin hole, It is possible to suppress friction with the piston pin hole during rotation of the internal combustion engine piston pin. Furthermore, since the concave portion formed on the peripheral surface of the piston pin for the internal combustion engine serves as an oil retention, the oil film retaining property of the lubricating oil can be enhanced, and a sufficient lubricating action by the lubricating oil can be obtained.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a piston pin for an internal combustion engine according to the present invention will be described below with reference to the drawings.
FIG. 1 (A) is a perspective view of a first embodiment of a piston pin for an internal combustion engine according to the present invention. In this drawing, a piston pin 1 for an internal combustion engine is provided with a molybdenum disulfide,
A solid lubricant layer 2 such as a fluororesin is formed in a stripe pattern in the longitudinal direction of the piston body 1a.

The solid lubricant layer 2 is formed by a screen printing method (see Japanese Patent Laid-Open No. 2-117072).

FIG. 1B is an enlarged cross-sectional view of a peripheral surface portion of a first embodiment of an internal combustion engine piston pin according to the present invention. As shown in FIG. The thickness of the solid lubricant layer 2 forms irregularities on the peripheral surface. That is, on the peripheral surface of the piston pin 1 for an internal combustion engine, the solid lubricant layer 2 projects, and the portion where the solid lubricant layer 2 is not formed is formed as the recess 6.
In this internal combustion engine piston pin 1, the lubricating oil is retained in the recess 6, and the oil film retaining property on the peripheral surface of the internal combustion engine piston pin 1 is improved.

Next, the piston pin 1 for an internal combustion engine having the above structure
An internal combustion engine equipped with is shown in FIG. In FIG. 2, the piston 8 and the connecting rod 10 are connected by the above-described internal combustion engine piston pin 1.

The piston 8 has a crown portion 11, skirt portions 12 and 12, and pin boss portions 13 and 13, and the pin boss portions 13 and 13 are provided with piston pin holes 14 and 14, respectively. Further, a small end hole 10a is formed at one end of the connecting rod 10.

Then, the small end hole 10a is positioned between the piston pin holes 14 and 14, and the piston pin holes 14 and 14 are
The piston pin 1 for the internal combustion engine is inserted into the piston rod 1, and the piston 8 and the connecting rod 10 are connected by being press-fitted into the small end hole 10a of the connecting rod 10. A large end hole is formed at the other end of the connecting rod 10 (not shown), and this large end hole is connected to a crankshaft (not shown).

According to the above construction, when the piston 8 is in operation,
The other end of the connecting rod 10 swings in the front-back direction in the figure. Therefore, the internal combustion engine piston pin 1 rotates with respect to the piston pin holes 14, 14. At this time, friction occurs between the internal combustion engine piston pin 1 and the inner surfaces of the piston pin holes 14 and 14. In this embodiment, the solid lubricant layer 2 is formed on the peripheral surface of the internal combustion engine piston pin 1. Therefore, the solid lubricant layer 2 can suppress friction between the internal combustion engine piston pin 1 and the piston pin holes 14, 14. Further, since the concave portion 6 holds the lubricating oil, the holding property of the lubricating oil 7 on the peripheral surface of the internal combustion engine piston pin 1 is enhanced, and a sufficient lubricating effect by the lubricating oil is obtained, and the internal combustion engine piston pin 1 is obtained. And piston pin hole 1
It is possible to prevent the seizure between 4 and 14.

As described above, in the internal combustion engine piston pin 1 of this embodiment, the lubrication by the solid lubricating layer 2 and the lubricating oil held in the recess 6 formed in a part of the solid lubricating layer 2 are sufficient. A lubricating effect is obtained. Therefore, an expensive material such as high-rigidity carbon fiber is not used, so that a piston pin for an internal combustion engine having excellent wear resistance can be obtained without increasing the manufacturing cost.

Further, in this embodiment, the concave portion 6
Are continuously formed in the longitudinal direction on the peripheral surface of the piston pin 1 for an internal combustion engine, the lubricating oil is circulated in the recess 6 to circulate the lubricating oil and cool the inner surface of the piston pin hole 14. You can

Next, a second embodiment of the piston pin for an internal combustion engine according to the present invention will be described with reference to the drawings. Constituent elements similar to those of the first embodiment will be designated by the same reference numerals and the description thereof will be omitted. To do.

FIG. 3 is a perspective view of a second embodiment of the piston pin for an internal combustion engine according to the present invention. In FIG. 3, the solid lubricant layer 2 is formed in a lattice pattern on the peripheral surface of the piston pin body 1a. That is, as shown in FIG. 4, unevenness is formed on the peripheral surface of the piston pin 1 for an internal combustion engine by the portion where the solid lubricant layer 2 is formed and the portion where the solid lubricant layer 2 is not formed. Of these, the portion where the solid lubricant layer 2 is not formed is formed as the recess 6.

In the second embodiment, as in the first embodiment, the solid lubricant layer 2 formed on the circumferential surface of the internal combustion engine piston pin 1 has the piston pin holes 14 and 14.
It is possible to suppress friction between the internal combustion engine piston pin 1 and the piston pin holes 14, 14 by contacting the inner surface of the piston pin 1.
Further, since the recess 6 serves as an oil reservoir for the lubricating oil 7, it is possible to enhance the retention of the lubricating oil 7 on the peripheral surface of the piston pin 1 for an internal combustion engine, and a sufficient lubricating effect of the lubricating oil 7 can be obtained. , Piston pin 1 for internal combustion engine and piston pin hole 14,
It is possible to prevent the seizure between 14 and.

In the piston pin 1 for the internal combustion engine of the first and second embodiments, a portion where the solid lubricant layer 2 is removed is provided on the peripheral surface of the piston pin 1 for the internal combustion engine, and the recess 6 is formed. The internal combustion engine piston pin 1
Even if the solid lubricant layer 2 is formed on the entire peripheral surface, it can be similarly implemented by reducing the thickness of a part of the solid lubricant layer 2 to form the recess 6 for retaining the lubricating oil.

[0023]

As described above, in the internal combustion engine piston pin according to the present invention, when the internal combustion engine piston pin is inserted into the piston pin hole, the solid lubricant contacts the inner surface of the piston pin hole. It is possible to suppress friction with the piston pin hole during rotation of the internal combustion engine piston pin. Furthermore, since the concave portion formed on the peripheral surface of the piston pin for the internal combustion engine serves as an oil retention, it is possible to enhance the oil film retention of the lubricating oil and obtain a sufficient lubricating effect by the lubricating oil. It is possible to prevent seizure between the internal combustion engine piston pin and the piston pin hole.

Therefore, since an expensive material such as high-rigidity carbon fiber is not used, a piston pin for an internal combustion engine having excellent wear resistance can be obtained without increasing the manufacturing cost.

[Brief description of drawings]

FIG. 1A is a perspective view of a first embodiment of a piston pin for an internal combustion engine according to the present invention. (B) It is an expanded sectional view of the peripheral surface part of the piston pin for internal combustion engines.

FIG. 2 is a cross-sectional view of an internal combustion engine piston equipped with the internal combustion engine piston pin.

FIG. 3 is a perspective view of a second embodiment of a piston pin for an internal combustion engine according to the present invention.

FIG. 4 is an enlarged cross-sectional view of a peripheral surface portion of the internal combustion engine piston pin.

[Explanation of symbols]

 1 Piston Pin for Internal Combustion Engine 1a Piston Pin Main Body 2 Solid Lubricant Layer 6 Recess

Claims (3)

[Claims] 1. A piston pin for an internal combustion engine, comprising a piston pin body made of a metal cylindrical material, and a solid lubricant layer formed on a peripheral surface of the piston pin body. A piston pin for an internal combustion engine, characterized in that a recess for retaining lubricating oil is formed in a part of the formed outer peripheral surface. 2. The piston pin for an internal combustion engine according to claim 1, wherein the solid lubricant layer is removed from the recess for retaining the lubricating oil. 3. The piston pin for an internal combustion engine according to claim 1, wherein a thin solid lubricant layer is formed in the recess for holding the lubricating oil.