JPS6144028Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piston device, and more particularly to a piston device having a piston-to-conrod connection mechanism that can withstand a large load.

As shown in FIG. 1, a piston 1 used in an internal combustion engine has a cylindrical shape with a closed upper end.
Both ends of the piston pin 4 are supported by through holes 3 of a pair of boss parts 2 formed in the skirt part. A through hole 6 at the small end of the connecting rod 5 is fitted into the intermediate portion of the piston pin 4, thereby connecting the piston 1 and the connecting rod 5. In such a piston device, the piston 1 is suddenly pressed downward every time an explosion occurs in the combustion chamber of the cylinder. However, since the piston 1 is connected to the crankshaft via the connecting rod 5, when it is pressed downward, a resistance force is generated to resist this pressure. As a result, the piston pin 4 attempts to flex and undergoes some degree of flexural deformation, as shown exaggeratedly by the chain line in FIG. Due to this deformation, a portion of the piston pin 4 is strongly pressed against the upper edge 7 inside the boss portion 2 of the piston 1, so that at this strongly pressed portion (hereinafter referred to as the contact portion), the upper edge 7 and the piston Concentrated stress occurs on pin 4. As a result, the abutting portion of the piston pin 4 is crushed in the direction of movement of the piston 1, and the piston pin 4 attempts to partially expand the periphery of the through hole 3 of the boss portion 2, so that Tensile stress is generated in the widened portion (that is, near the upper edge 7 inside the boss portion 2). In particular, when the load on the crankshaft is high, the value of the tensile stress is large, so
A crack will occur near the upper edge 7 inside the boss portion 2 of the piston 1, or the boss portion 2 will be destroyed.

Therefore, in conventional piston devices, the diameter of the piston pin 4 is increased or the wall thickness of the piston pin 4 is increased to increase the rigidity of the piston pin 4, or the through hole 3 of the boss portion 2 of the piston 1 is made rigid. Either by inserting a higher bush, or by reducing the distance between the boss parts 2 of the piston 1,
This prevents cracks from occurring near the upper edge 7 inside the boss portion 2 of the piston 1 or from breaking the boss portion 2. However, if the piston device is configured in this way, the weight of the piston 1 increases, the number of manufacturing steps increases, and the manufacturing cost increases.

The present invention was made with the aim of correcting such problems, and includes a piston device configured to connect a substantially cylindrical piston and one end of a connecting rod with a piston pin. A pair of boss portions provided on the piston to support both ends of the pin, a pair of arm portions provided on the connecting rod so as to form a substantially U-shape as a whole, and and a protrusion protruding from the piston between these boss parts so as to form a substantially E-shape with the boss part, and the protrusion has a bearing surface for receiving the piston pin. one of the arm portions is disposed between one of the boss portions and the protruding piece, and the other arm portion is disposed between the other of the boss portions and the protruding piece; The piston is configured to support the piston pin by the pair of boss portions and the bearing surface of the projecting piece, and the connecting rod is coupled to the piston pin near the pair of arm portions. The present invention relates to a piston device characterized by the following configuration. Therefore, according to the present invention, since deformation of the piston pin is effectively prevented, stress is not concentrated on the edge of the boss, and the U-shaped part of the cooking rod is connected to the E-shaped part of the piston. Since the piston pin is connected to the piston pin, stress is not concentrated on the edge of the piston boss portion where the piston pin is connected, and breakage of the connected portion can be prevented.

An example in which the present invention is applied to a piston for a diesel engine will be described below. 2 and 3 show a piston device according to a first embodiment of the present invention, in which a piston 11 is made by casting aluminum alloy or iron, and has a cylindrical shape with a closed upper end. It is composed of Three annular grooves 12 for mounting piston rings are formed on the outer peripheral surface on the land side. Further, a recess 13 is formed on the outer surface of the upper end of the piston 11, thereby increasing combustion efficiency.

A pair of boss portions 1 are provided on the skirt portion of the piston 11.
4 are integrally connected facing each other. A through hole 15 is formed in each of the pair of boss portions 14, and these through holes 15 constitute a bearing portion of the piston pin 16. That is, both ends of the piston pin 16 are supported by the through hole 15, and a retaining ring 18 fitted in an annular groove 17 formed on the inner peripheral surface of the through hole 15 prevents the piston pin 16 from falling off. has been done. In this embodiment, the piston pin 16 consists of a hollow shaft (see FIG. 3).

A pair of arm portions 20 are connected to the small end of the connecting rod 19 in the longitudinal direction of the connecting rod 19, which is connected to the piston 11 via the piston pin 16, and the small end of the connecting rod 19 as a whole has a substantially U-shape. It is structured like this. Each of these arm portions 20 has a through hole 21 formed therein, and is connected to the piston pin 16 through these through holes 21. Corresponding to the U-shaped small end of the stove rod 19, a downwardly protruding protrusion 22 is integrally connected to the inside of the upper end of the piston 11, and this protrusion 22 and the pair of boss parts 14 It is configured in an E-shape. The projecting piece 22 extends into the gap between the pair of arm parts 20 of the connecting rod 19 disposed between the pair of boss parts 14 of the piston 11, and has a through hole formed in the projecting piece 22. The piston pin 16 is fitted through the hole 23 . This through hole 23 forms a bearing surface 24 to prevent deformation of the piston pin 16 during an explosion.

That is, since the piston pin 16 has both ends supported by the through hole 15 of the boss portion 14 and its longitudinally intermediate portion supported by the through hole 23 of the projection piece 22, the piston pin 16 is 1
The downward force of the piston pin 1 is transmitted to the piston pin 16 by the pair of bosses 14 and the intermediate protrusion 22. Therefore, the bearing area of the piston pin 16 is increased, and the intermediate portion of the piston pin 16 is particularly supported by the bearing surface 24 of the protruding piece 22, so that the piston pin 16 is effectively prevented from being bent and deformed, and the boss portion 14 is Stress will not be concentrated on the inner upper edge 25, and the boss portion 14 will not be cracked or the piston 11 will be destroyed. Therefore, even with the same size piston, it becomes possible to output a larger output, or it becomes possible to downsize the internal combustion engine.

Next, the second embodiment of the present invention is shown in FIGS. 4 and 5.
This will be explained with reference to the diagram. Note that the same reference numerals are given to the same components as in the first embodiment, and the explanation thereof will be omitted.

In this embodiment, at the small end of the connecting rod 19, not only a bearing surface is formed on the pair of arm portions 20, but also a bearing surface for the piston pin 16 is formed between these arm portions 20. There is. As shown in FIG. 5, the bearing surface between the arm portions 20 is configured to come into contact with approximately one-third of the circumference of the piston pin 16 (approximately 120° in terms of the center angle). There is. Therefore, the bearing area of the connecting rod 19 is increased, and the connecting rod 19 has an advantage in strength accordingly.
Correspondingly, the length of the projecting piece 22 is shortened to such a length that it partially contacts the piston pin 16 in the circumferential direction. A bearing surface 24 is formed at the tip of this projecting piece 22, and this bearing surface 24 receives the piston pin 16. Therefore, in this embodiment as well, deformation of the piston pin 16 and the piston 11 is mainly prevented by the bearing surface 24 of the projecting piece 22, and damage to the piston 11 is prevented.

Although the present invention has been described above with reference to embodiments, the present invention is not limited to the above-mentioned embodiments, and various modifications can be made based on the technical idea of the present invention. For example, although the above embodiment relates to a piston for a diesel engine, the present invention is applicable to various other piston devices.

As mentioned above, the present invention provides a pair of arm portions on the conrod so as to form a substantially U-shape as a whole, and a pair of arm portions are provided between these boss portions so as to form a substantially E-shape together with a pair of boss portions. A protruding piece is provided on the piston and a bearing surface is formed on the protruding piece, and a piston pin is supported on the piston by the pair of boss parts and the bearing surface of the protruding piece, and the pair of boss parts The pair of arm portions are disposed between the piston pin and the protruding piece, and the connecting rod is connected to the piston pin near these arm portions. Therefore, the bearing area provided on the protrusion increases the bearing area, and the intermediate portion of the piston pin is received by the bearing surface of the protrusion, and the U-shaped portion of the stove is connected to the E-shape of the piston. Since the piston pin is connected to the piston pin, deformation of the piston pin and the piston is effectively prevented.This prevents stress from being concentrated on the edge of the piston boss. The edge stress of the connecting portion with the piston pin is not concentrated, and breakage of the connecting portion can be prevented.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of the main parts of a conventional piston device, FIG. 2 is a longitudinal cross-sectional view of the main parts of the piston device showing a first embodiment of the present invention, and FIG.
FIG. 4 is a longitudinal sectional view of a main part of a piston device showing a second embodiment of the present invention, and FIG. 5 is a sectional view taken along the line - in FIG. 4. In addition, in the symbols used in the drawings, 11...piston, 14...boss portion, 15...through hole, 16...
...Piston pin, 19...Conn rod, 20...
Arm portion, 22... projecting piece, 24... bearing surface.

Claims (1)

[Claims for Utility Model Registration] In a piston device configured to connect a substantially cylindrical piston and one end of a connecting rod by a piston pin, a piston is provided on the piston to support both ends of the piston pin, respectively. a pair of boss portions provided on the conrod so as to form a substantially U-shape as a whole; and projecting pieces protruding from the piston between the boss parts, each of the protruding pieces forming a bearing surface for receiving the piston pin, and one of the arm parts being connected to one of the boss parts. and the protruding piece, and the other of the arm parts is arranged between the other of the boss parts and the protruding piece, and the bearing of the pair of boss parts and the protruding piece in the piston The piston device is configured to support the piston pin by a surface, and the connecting rod is configured to be coupled to the piston pin near the pair of arm portions.