JPH0529580Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an assembly structure of a piston and a connecting rod, for example in a diesel engine.

The piston and connecting rod of an internal combustion engine are repeatedly subjected to the explosion pressure within the cylinder and the inertial force that occurs when the piston and connecting rod move.
They are placed under extremely harsh conditions from a stress standpoint.

A typical prior art is shown in FIG.
A piston pin 3 is inserted into and fixed to a piston 2 that is inserted into the cylinder liner 1 and moves up and down in FIG. 1. A connecting rod 5 is connected to the piston pin 3 via a sliding bearing 4.

In the event of an explosion, the piston 2 is subjected to a load indicated by the reference numeral 6, as shown in FIG. Also, when the piston 2 and the connecting rod 5 move, the connecting rod 5 is moved by the inertia force 8 of the piston 2 at its top dead center.
A reaction force 9 acts on . In this way, the piston pin 3 is bent and deformed. As a result, the boss portion to which the piston pin 3 is attached is damaged.

The piston pin 3 cannot be made unnecessarily large due to dimensional restrictions of the piston 2. Therefore, the stress in the piston pin 3 increases as the explosion pressure increases or as the inertia force increases during high-speed rotation.
growing. Since the piston pin 3 receives a load due to inertial force, the upper part of the connecting rod 5 must have a sufficient length A in the axial direction to be supported by the sliding bearing 4. Therefore, the length 2·B of the piston pin 3 in the axial direction, by which the piston pin 3 is fixed to the piston 2, cannot be set to a sufficiently large value. Therefore, the surface pressure in the portion of the piston pin 3 over the length 2·B becomes high.

Other prior art techniques form a concave spherical seat in the piston 2, connect a convex spherical part formed in the upper part of the connecting rod 5, and perform an angular displacement about the axis of the piston 2, thereby Prevents scuffing of piston ring stays and sliding surfaces. According to such prior art, the spherical seat of the piston and the spherical portion of the connecting rod move while being in direct frictional contact with each other under high surface pressure, and the lubrication conditions are poor, resulting in severe wear and easy seizure. Further, machining the spherical seat and the spherical portion of the connecting rod is time-consuming. If a bearing were to be installed between the spherical seat of the piston and the spherical part of the connecting rod, it would be difficult to process the bearing itself;
It is difficult to bring the bearing metal of the bearing into close contact with the spherical seat of the piston and the spherical portion of the connecting rod. If such a tight fit is not possible, the bearing will be subject to repeated loading due to the explosion pressure and inertia forces within the cylinder, and thus damage will occur, for example between the spherical seat of the piston and the bearing surface, or between the back of the bearing and the connecting rod six. There is a risk that fretting corrosion will occur between the piston and the inner surface, causing damage to the piston.

In summary, these prior art techniques have poor reliability in order to provide higher output power.

In other prior art (Utility Model Application Publication No. 54-64862), the first
A preload applying device (for example, an elastic member such as a spring) is inserted between a member (for example, a piston) and a second member (for example, a connecting rod), and
A pressure greater than the minimum value of the fluctuating load on the member is applied to the second member in the pushing direction of the first member as a preload on the second member.
Added to parts.

By doing this, the piston pin bearing 7 and the piston pin 4 are separated, and there is no mutual metal contact, and lubrication is achieved, thereby preventing seizure of the bearing.

This prior art requires springs and the like and is obviously complex in construction.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a piston and connecting rod assembly structure for an internal combustion engine that solves the above-mentioned problems of the prior art, improves reliability, and simplifies construction.

In the present invention, a piston pin 17 is provided at one end of the connecting rod 16 and protrudes outward from both sides of the connecting rod 16.
17a is integrally configured, and the piston 11 has piston pins 17, 17a.
First mounting holes 15, 15a, 40 having a semicircular cross section perpendicular to the axis are formed to support the piston pins 17, 17a, and the first mounting holes 15, 15a, 40 In between are semicircular arc bearing metals 25, 35, 36.
The entire semi-outer circumferential surface of the connecting rod 16 side of the portion 34 of the piston pins 17, 17a that protrudes outward from both sides of the connecting rod 16 has semicircular bearing metals 26, 37 interposed therebetween, and the mounting members 22, The mounting members 22, 39 are supported by the second mounting hole 23 having a semicircular cross section perpendicular to the axis, which is formed in the bolt 21, 41.
This is an assembly structure of a piston and a connecting rod for an internal combustion engine, characterized in that it is removably fixed to a piston 11 via a piston.

Example FIG. 3 is a front view of the present invention, and FIG. 4 is a front view of the present invention.
FIG.
The figure is a sectional view seen from FIG. 3-, and FIG. 6 is an exploded perspective view thereof. Explaining with reference to these drawings, the piston 11 has a skirt 12
, a crown 13 fixed to the top thereof, and a pair of hanging pieces 14 extending from the skirt 12 to the side opposite to the crown 13. The hanging pieces 14 are arranged at intervals in the circumferential direction, and in this embodiment, the piston 11
are placed on one diameter line of each. The skirt 12 has a mounting hole 1 having a semicircular cross section perpendicular to the axis.
5 is formed. At one end of the connecting rod 16,
A piston pin 17 is formed integrally with the connecting rod 16 so as to protrude outwardly from both sides thereof, and a crank pin 19 is attached to the other end of the connecting rod 16 by a mounting member 18. The connecting rod 16 and the piston pin 17 may be integrally formed by machining or the like, or may be integrally formed by bolting, welding, or the like.

The piston pin 17 has a through hole 2 in its axial direction.
0 is formed, reducing weight. The piston pin 17 is attached via a sliding bearing 24 to an attachment hole 15 formed in the skirt 12 and an attachment hole 23 of an attachment member 22 fixed to the skirt 12 with a bolt 21.

The sliding bearing 24 includes a bearing metal 25 formed in a semicircular shape along the mounting hole 15, and each mounting member 22.
A semi-circular bearing metal 26 is provided along the mounting hole 23 of the bearing metal 26 . The bearing metal 25 is in contact with the entire semi-outer circumferential surface of the piston pin 17 on the side opposite to the connecting rod 16 (that is, the piston side), and the bearing metal 26 is in contact with the connecting rod 16 of the piston pin 17 that protrudes outward on both sides. It contacts the entire half outer peripheral surface of the 16 side.

FIG. 7 is a perspective view of the piston 11 seen from below in FIGS. 3 and 4. The bearing metal 25 is
The connecting rod 16 is fixed by a fixing piece 29 fixed to the end face of the skirt 12 with a bolt 28 at the location where the connecting rod 16 is located. The bearing 24 has a piston 1
Lubricating oil is supplied into the interior of the housing 1 through an oil hole 30. Such lubricating oil supply routes are well known to those skilled in the art. A threaded hole 31 is formed in the end face of this skirt 12, into which the aforementioned bolt 21 that passes through the mounting member 22 is screwed.

In this way, the piston pin 17 is integrally formed in the connecting rod 16, and the piston pin 17 is attached to the piston 11 by the bearing 24, so that
Sufficient strength can be achieved to withstand explosive loads and inertia loads.

That is, the present invention provides a piston and connecting rod assembly structure that is reliable even when the maximum pressure inside the cylinder increases and the engine speed increases, which inevitably occur when increasing the output of the engine.

If the maximum pressure inside the cylinder increases, the load applied from the top surface of the piston to the piston pin will naturally increase, so the stress, surface pressure, and deflection of the piston pin will increase. In order to suppress this to a certain level, the piston pin must be made larger, and the best way to do this is to integrally configure the piston pin and the connecting rod.

On the other hand, if the engine speed is increased, the inertial force of the piston increases in proportion to the square of the speed, so the load on the piston pin increases. In a reciprocating engine such as the case of the present application, the load on the piston pin acts repeatedly. In the case of parts that are subjected to repeated loads, there are many cases in which damage occurs immediately if the load level increases too much.
Measures are needed to prevent this.

Therefore, in the above embodiment, the bearing metals 25, 2
The present invention is characterized by the use of a sliding bearing 24 having a diameter of 6, and the structure that supports the bearing metals 25 and 26. That is, the piston pin 17 and the connecting rod 1
6 is integrally constructed as mentioned above,
The upper surface has a half-split bearing metal 25 on the entire surface.
is provided, and the central part of the bearing metal 25 is firmly fixed by the bolt 28 and the fixing piece 29, so even if it is subjected to repeated loads, the bearing metal 2
To prevent fretting from occurring at the contact surface between 5 and the skirt 12.

Also, on both end faces of the connecting rod 16, avoiding the swinging part,
The bearing metal 25 extends, and here the bolt 21
Since it is firmly fixed using the mounting member 22 and the bearing metal 26 and the mounting hole 23,
Further, the end of the bearing metal 25 and the mounting hole 15 of the skirt 12 are in close contact with each other, so that fretting corrosion does not occur even when receiving a fluctuating load.
As the bearing metal 26, a so-called crush metal can also be used.

Since the outer surface of the piston pin 17 is in contact with a bearing surface with good lubricity, there is no problem. Bearing 24
The piston 11 and the connecting rod 16 need only be replaced when damaged, and maintenance is easy.

FIG. 8 is a sectional view of another embodiment of the present invention,
FIG. 9 is a sectional view taken along the cutting plane line -. This embodiment is similar to the previous embodiment and corresponding parts are provided with the same reference numerals. In this embodiment, the hanging piece 14a continuous to the skirt 12 is formed over the entire circumference.

FIG. 10 is a sectional view of still another embodiment of the present invention. Although this embodiment is similar to the embodiment shown in FIGS. 8 and 9 above, it should be noted that the skirt 12 is made of metal such as aluminum to reduce weight, and the crown 13 and mounting member 22 are made of metal such as aluminum to reduce weight.
or made of steel. The bolt 31 passes through the mounting member 22 and the skirt 12 and is screwed into a threaded hole 32 formed in the crown 13.

FIG. 11 is a sectional view of still another embodiment of the present invention. This embodiment is similar to the embodiment shown in FIGS. 3-7 described above. What should be noted is that the piston pin 17a, which is integral with the connecting rod 16, has a large diameter portion 33 that continues to one end of the connecting rod 16, and a support shaft that extends and projects from both ends of the large diameter portion 33 in the axial direction. 34. The large diameter portion 33 has a semi-circular bearing metal 35
Attachment hole 15a formed in skirt 12 by
Supported by The support shaft 34 is attached to the attachment hole 40 of the skirt 12 by an attachment member 39 via a bearing 38 that includes an upper semicircular bearing metal 36 and a lower semicircular bearing metal 37. This mounting member 39 is fixed to the end surface of the skirt 12 by bolts 41. According to this embodiment, since the support shaft 34 has a small diameter, the mounting member 39 can be fixed to the skirt 12 using a relatively large bolt 41. In this embodiment, instead of making the piston pin 17 have a large diameter as a whole,
The support shaft 34 of the piston pin 17a is configured to have a small diameter. The reason why the support shaft 34 can be made small in diameter is that the load due to inertia force is relatively smaller than the load due to explosion pressure, and therefore the bearing area of the bearing 38 may be small. The force is received by a bearing 38. In this way, the size of the bolt 41 can be made somewhat larger than the size of the piston 11.

As described above, according to the present invention, the piston pin and the connecting rod are integrally configured, and the piston pin is connected to the piston by the mounting member through a sliding bearing between the piston pin, the piston, and the mounting member. As a result, the load at the time of explosion and the load due to inertia force can be received with great strength, and reliability is improved. Furthermore, since it becomes possible to improve the strength, it becomes possible to reduce the fuel cost rate of the internal combustion engine by increasing the explosion pressure in the cylinder, for example.

In particular, according to the present invention, the bearing metals 25, 35,
36, 26, and 37 are semicircular arc shapes, and have an extremely simple configuration.

Moreover, the mounting members 22 and 39 are bolts 21 and 41.
Since the bearing metals 25, 3 having such a simple structure can be attached to and detached from the piston 11 by
5, 36 and 26, 37 can be easily replaced, and maintenance is extremely easy.
This makes it possible to extend the life of the connecting rod 16.

Furthermore, in the present invention, the piston pins 17, 1
The entire half outer peripheral surface of the piston side of the piston 7a is connected to the first piston 11 through the bearing metals 25, 35, and 36.
The entire semi-outer peripheral surface of the connecting rod 16 side of the portion 34 of the piston pins 17, 17a that is supported by the mounting holes 15, 15a, 40 and protrudes outward from both sides of the connecting rod 16 is supported by the bearing metals 26, 37. , mounting member 2
Since it is supported by the second mounting holes 23 of 2 and 39, those bearing metals 25, 35, 36 and 26,
37 can be brought into close contact with the contact surface without creating a gap. This achieves the excellent effect of reliably preventing fretting corrosion.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the prior art, and Figure 2 is its first
A cross-sectional view for explaining the load acting on the piston pin 3 of the prior art shown in the figure, FIG. 3 is a front view of one embodiment of the present invention, and FIG. 4 is taken from the cutting plane line of FIG. 5 is a sectional view taken from the cutting plane line - of FIG. 3, and FIG. 6 is a sectional view taken from the section line -
An exploded perspective view of the illustrated embodiment, FIG. 7 shows the piston 1
1, a perspective view seen from below in FIGS. 3 and 4;
FIG. 8 is a cross-sectional view of another embodiment of the present invention, FIG. 9 is a cross-sectional view taken from the cutting plane line - of FIG. 8, and FIG.
The figure is a sectional view of still another embodiment of the present invention, No. 11.
The figure is a sectional view of another embodiment of the present invention. 11...Piston, 12...Skirt, 13...
... Crown, 15, 15a, 23, 40 ... Mounting hole, 16 ... Connecting rod, 17, 17a ... Piston pin, 22, 39 ... Mounting member.

Claims (1)

[Claims for Utility Model Registration] One end of the connecting rod 16 is integrally formed with piston pins 17, 17a that protrude outward on both sides of the connecting rod 16, and the piston 11 has piston pins 17, 17a.
First mounting holes 15, 15a, 40 having a semicircular cross section perpendicular to the axis are formed to support the piston pins 17, 17a, and the first mounting holes 15, 15a, 40 In between are semi-circular bearing metals 25; 35, 36.
The entire semi-outer circumferential surface of the connecting rod 16 side of the portion 34 of the piston pins 17, 17a that protrudes outward from both sides of the connecting rod 16 has semicircular bearing metals 26, 37 interposed therebetween, and the mounting members 22, The mounting members 22, 39 are supported by the second mounting hole 23 having a semicircular cross section perpendicular to the axis, which is formed in the bolt 21, 41.
An assembly structure of a piston and a connecting rod for an internal combustion engine, characterized in that it is detachably fixed to a piston 11 via a piston.