JP2017180600A - Piston and connecting rod connection structure - Google Patents

Abstract

Disclosed is a connecting rod / piston connection structure that can disperse the places where wear occurs in a sliding bearing provided between a small end of a connecting rod and a piston pin, and reduce the life reduction due to wear. To do. By connecting a piston pin 2 supported by a piston 1 to a slide bearing 4 inserted into a small end 30 of the connecting rod 3, the connecting rod 3 and the piston 1 are connected. The small end portion 30 has first oil holes 43a and 43b to which lubricating oil is supplied, and the slide bearing 4 has a second oil hole 43a (or 43b) that can communicate with the first oil hole 30a. Have. At least one of the first oil hole 30a and the second oil hole 43a (or 43b) is provided in plural along the circumferential direction of the surface where the small end 30 and the plain bearing 4 face each other. The slide bearing 4 is inserted so as to be relatively movable in the circumferential direction with respect to the small end portion 30, and includes a restriction portion 4 a that restricts the movement of the slide bearing 4 in the axial direction with respect to the small end portion 30. [Selection] Figure 1

Description

  The present invention relates to a connection structure between a piston and a connecting rod of an internal combustion engine, and more particularly, to a connection structure in which a small end portion of a connecting rod is connected to a piston pin supported by the piston via a slide bearing.

  In a reciprocating internal combustion engine, a small end portion of a connecting rod is connected to a piston that reciprocates in a cylinder block so as to swing and rotate. The piston and the connecting rod are connected by inserting a piston pin supported by the piston through a pin insertion hole formed in a small end portion of the connecting rod. In such a connecting structure between the connecting rod and the piston, it is desirable to reduce the sliding friction between the piston pin and the connecting rod. Therefore, a bearing is interposed between the small diameter portion of the connecting rod and the piston pin. .

  Patent Document 1 discloses an example in which a roller bearing is provided between a piston pin and a small end portion of a connecting rod.

JP 2008-101652 A

  However, in an internal combustion engine, since the load applied to the piston pin is large, when a roller bearing with low load resistance is used as in Patent Document 1, deterioration and breakage are likely to occur, and it is difficult to obtain a sufficient life. There is a problem of becoming. Therefore, as shown in FIG. 4, a plain bearing B is also used between the piston pin P and the small end portion SE of the connecting rod CR. Since the plain bearing B has a large area for receiving a load, a higher load resistance can be obtained compared to the roller bearing, and an improvement in life can be expected.

  However, in the current high-performance internal combustion engine, as shown in FIG. 4, the piston pin P is bent by the load F applied to the piston pin P, and a large load is applied to a specific portion of the slide bearing B. As shown in (a) and (b), there arises a problem that only specific portions (a1, a2) in the slide bearing B are greatly worn (for example, about 12 μm or more). When such specific part wear (uneven wear) occurs, the clearance between the slide bearing and the piston pin is enlarged, and a hitting sound is generated while the internal combustion engine is driven, or the slide bearing is burned out. Occurs.

  The present invention has been made paying attention to the above-mentioned problems, and distributes the places where wear occurs in the slide bearing provided between the small end portion of the connecting rod and the piston pin, thereby reducing the life due to wear of the slide bearing. An object is to provide a connecting structure between a connecting rod and a piston that can be reduced.

  In order to achieve the above object, the present invention provides a piston for connecting the connecting rod and the piston by inserting a piston pin supported by the piston into a slide bearing inserted into the small end portion of the connecting rod. A connecting rod connecting structure, wherein the small end portion has a first oil hole to which lubricating oil is supplied, and the sliding bearing is a second oil hole capable of communicating with the first oil hole. And at least one of the first oil hole and the second oil hole is provided in plural along the circumferential direction of the surface where the small end portion and the slide bearing face each other, and the slide bearing is It is inserted so as to be relatively movable in the circumferential direction with respect to the small end portion, and is provided with a restricting portion for restricting movement of the slide bearing in the axial direction with respect to the small end portion.

  According to the present invention, since the slide bearing is inserted so as to be relatively movable in the circumferential direction with respect to the small end portion of the connecting rod, the portion of the slide bearing to which a large force is applied from the piston pin moves in the circumferential direction. To do. Therefore, in the connecting structure of the connecting rod and the piston, it is possible to disperse the places where wear occurs in the slide bearing provided between the small end portion of the connecting rod and the piston pin. The small end portion of the connecting rod has a first oil hole to which lubricating oil is supplied, while the slide bearing has a second oil hole that can communicate with the first oil hole. Since at least one of the hole and the second oil hole is provided in plural along the circumferential direction of the surface where the small end portion and the slide bearing face each other, the first oil hole and the second oil hole The second oil hole communicates with the piston pin multiple times to maintain a good lubrication state between the piston pin, the small end of the connecting rod and the piston pin, and to reduce the life reduction due to wear of the slide bearing. become.

It is a vertical front view which shows the connection structure of the connecting rod and piston in embodiment of this invention. It is a perspective view which shows the small end part and sliding bearing of the connecting rod shown in FIG. It is a figure which shows the plain bearing shown in FIG. 2, and its control part, (a) has shown the initial state of a control part, (b) has each shown the state which bent the control part. It is a schematic diagram which shows the state in which the load was applied to the piston pin. It is a figure which shows the generation | occurrence | production state of the abrasion in the edge part of a slide bearing, (a) is a front view of a slide bearing, (b) is an expanded vertical side view of a slide bearing.

An embodiment of a connecting structure of a piston rod and a connecting rod according to the present invention will be described with reference to FIGS.
As is well known, a piston of an internal combustion engine is connected to a crankshaft via a connecting rod, and the reciprocating motion of the piston is converted into a rotational motion of the crankshaft via the connecting rod. FIG. 1 is a longitudinal front view showing a connecting structure between the piston 1 and a connecting rod 3, and FIG. 2 is a perspective view showing one end (small end) of the connecting rod 3.

  As shown in FIG. 1, a small end 30 of a connecting rod 3 is connected to the piston 1 by a piston pin 2 so as to be able to swing and rotate. Further, in order to reduce the frictional resistance generated between the outer peripheral surface of the piston pin 2 and the inner peripheral surface of the small end 30 when the connecting rod 3 swings and rotates with respect to the piston pin 2, the small end 30. A sliding bearing 4 is provided between the piston pin 2 and the piston pin 2.

  As shown in FIG. 2, the plain bearing 4 has a cylindrical shape with both ends opened, and is press-fitted into the inner peripheral surface of the small end portion 30. The pressure input to the small end portion 30 of the slide bearing 4 is such that the slide bearing 4 moves in the circumferential direction within the small end portion 30 by the force received from the piston pin 2 when the connecting rod 3 swings and rotates with respect to the piston pin 2 ( The power is about to rotate).

  Furthermore, the restriction part 4a which protrudes outward along the axial direction of a slide bearing is formed in the edge of the opening parts 41 and 42 on either side of the slide bearing 4 in this embodiment. The restricting portion 4 a is formed so as to protrude outward from the edges of the left and right openings 41 and 42 of the sliding bearing 4 in a state in which the sliding bearing 4 is press-fitted into the connecting rod 3.

  In the present embodiment, a total of four restricting portions 4 a are provided, two at each end edge of the left and right openings 41, 42 of the slide bearing 4. These restricting portions 4a project in the radial direction of the sliding bearing 4 as shown in FIG. 3B after the sliding bearing 4 is press-fitted (inserted) into the small end portion 30 of the connecting rod 3. To bend. As a result, the restricting portions 4a provided at the edges of the left and right openings 41 and 42 of the slide bearing 4 come into contact with the edges of the left and right openings 31 and 32 of the small end 30 and move in the axial direction. To regulate. As described above, the sliding bearing 4 in the present embodiment is capable of moving (rotating) in the circumferential direction on the inner surface of the connecting rod 3 and is restricted from moving in the axial direction.

  In addition, the small end portion 30 of the connecting rod 3 is formed with an oil hole (first oil hole) 30a that penetrates the peripheral wall and has a long hole shape in a predetermined range along the circumferential direction. Furthermore, a plurality of oil holes (second oil holes) penetrating the peripheral wall portion 40 are formed in the peripheral wall portion 40 of the slide bearing 4. In the present embodiment, as an example, two oil holes 43a and 43b (second oil holes) are formed on the same circumference of the peripheral wall portion 40 at equal intervals, and the oil holes 43a and 43b are It arrange | positions so that it may mutually oppose. That is, the angle (center angle) formed by the line connecting the oil hole 43a and the central axis of the peripheral wall 40 and the line connecting the oil hole 43b and the central axis of the peripheral wall 40 is approximately 180 degrees. The oil holes 43a and 43b are formed.

  Further, the oil holes 43 a and 43 b are formed at positions where they can communicate with the first oil hole 30 a formed in the small end portion 31 of the connecting rod 3. That is, each oil hole 41a, 41b is formed at a position that faces the first oil hole 30a of the connecting rod 3, or a position that can face a region where the first oil hole extends in the circumferential direction.

  In the internal combustion engine provided with the connecting structure of the connecting rod 3 and the piston 1 having the above-described configuration, the piston 1 reciprocates in the cylinder by explosion (combustion) in the combustion chamber, and the connecting rod 3 is connected to the piston pin 2 accordingly. Oscillate around the center. The reciprocating movement of the piston is transmitted to the crankshaft (not shown) via the large end (not shown) of the connecting rod 3 to rotate the crankshaft. At this time, since the connecting rod 3 swings and rotates with respect to the piston pin 2 held by the piston 1, the inner surface of the slide bearing 4 press-fitted into the small end portion 30 is in relation to the outer peripheral surface of the piston pin 2. Will slide and wear.

  In particular, in a recent high-performance internal combustion engine, the force applied from the piston pin 2 to the sliding bearing 4 tends to increase as the in-cylinder pressure increases. Power is added. For this reason, in the conventional slide bearing in which the relative position between the piston pin and the slide bearing is always kept constant, only a fixed position where a large frictional resistance is generated is significantly worn.

  On the other hand, in the coupling structure of the piston and the connecting rod in this embodiment, the sliding bearing 4 can move in the circumferential direction in the small end portion 30 of the connecting rod 3 as the connecting rod 3 swings and rotates. Press-fitted with pressure. That is, the force is generated between the sliding bearing 4 and the small end 30 compared to the force of the rotational direction component applied to the sliding bearing 4 from the piston pin 2 when the small end 30 of the connecting rod 3 swings and rotates. A plain bearing is press-fitted into the small end so that the frictional force is reduced. For this reason, as the connecting rod 3 swings and rotates, the slide bearing 4 gradually rotates in the small end portion 30 of the connecting rod 3. As a result, in the slide bearing 4, a portion to which a large force is applied from the piston pin 2, that is, a worn portion moves in the circumferential direction, and the wear state in the slide bearing is dispersed in the circumferential direction. For this reason, conventional uneven wear is suppressed.

  Further, during the operation of the internal combustion engine, the lubricating oil is injected into the piston 1 from an oil jet (not shown), and the lubricating oil enters the first oil hole 30a of the connecting rod 3 from the internal space S of the piston. Here, when the first oil hole 30a and the second oil hole 43a (or 43b) formed in the slide bearing 4 are in communication, the lubricating oil that has entered the first oil hole 30a is second. The oil hole 43a (or 43b) is supplied to the outer peripheral surface of the piston pin 2. Thereby, the lubrication between the piston pin 2 and the slide bearing 4 is performed, the swinging motion of the connecting rod 3 is smoothly performed, and the wear of the slide bearing 4 is further reduced.

  Further, since the sliding bearing 4 relatively moves (relatively rotates) in the circumferential direction in the small end portion 30 by the swinging rotation of the connecting rod 3, the second oil hole 43a (or 43b) becomes the first oil hole. A state of moving to a position that does not communicate with 30a also occurs. However, in the present embodiment, the two second oil holes 43a and 43b are formed in the sliding bearing 4 at positions facing each other, and the first oil hole 30a is formed in a long hole shape. For this reason, even if one of the second oil holes 43a (or 43b) is separated from the communication position with the first oil hole 30a, the slide bearing 4 is rotated thereafter, so that the other second oil hole 43b (or 43a) communicates with the first oil hole 30a and can supply the lubricating oil to the piston pin 2. That is, when the slide bearing 3 is rotated by an angle of {(180 degrees) − (first oil hole forming angle)}, the first oil hole 30a and the second oil hole 43b (or 43a) are connected. The first oil hole and the second oil hole communicate with each other a plurality of times during one rotation of the slide bearing. Thus, in the present embodiment, the first oil hole 30a and the second oil hole 43a (or 43b) communicate with each other in different combinations by relative movement of the slide bearing 4 in the circumferential direction with respect to the small end portion 30. be able to. For this reason, the supply of oil to the piston pin 2 is not blocked for a long period of time, and a good lubricating state can be maintained between the piston pin 2 and the connecting rod 3.

  Further, since the slide bearing 4 is engaged with the end edges of the openings 31 and 32 of the small end 30 of the connecting rod 3 and the movement in the axial direction is restricted, the first oil hole 30a The relative position with the second oil hole does not shift in the axial direction. That is, even if the slide bearing 4 rotates, the second oil holes 43a and 43b do not fall into a state incapable of communicating with the first oil hole 30a, and a good lubrication state can be maintained.

(Other embodiments)
In the above-described embodiment, an example in which a long-hole-shaped oil hole (first oil hole) is provided in the connecting rod and oil holes (second oil holes) are provided in a plurality of locations of the slide bearing has been described. However, the present invention is not limited to the above embodiment. For example, a plurality of first oil holes may be provided in the connecting rod, a single oil hole may be provided in the slide bearing, or a single or a plurality of oil holes may be formed in both the connecting rod and the slide bearing. . Moreover, the shape of each oil hole is not specifically limited. Furthermore, the restriction part formed in the slide bearing only needs to restrict the movement of the slide bearing in the axial direction, and the number and position of the restriction parts are not particularly limited.

DESCRIPTION OF SYMBOLS 1 Piston 2 Piston pin 3 Connecting rod 4 Sliding bearing 4a Restriction part 30 Small end part 30a 1st oil hole 43a, 43b 2nd oil hole

Claims (1)

A piston-connecting rod connecting structure for connecting the connecting rod and the piston by inserting a piston pin supported by the piston into a slide bearing inserted into the small end of the connecting rod,
The small end portion has a first oil hole to which lubricating oil is supplied,
The slide bearing has a second oil hole capable of communicating with the first oil hole,
At least one of the first oil hole and the second oil hole is provided in plural along a circumferential direction of a surface where the small end portion and the plain bearing are opposed to each other,
The slide bearing includes a restricting portion that is inserted so as to be relatively movable in the circumferential direction with respect to the small end portion, and that restricts movement of the slide bearing in the axial direction with respect to the small end portion. Characteristic piston and connecting rod connection structure.

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