KR20250096002A - Connecting rod bearing and engine system containing the same - Google Patents

Abstract

One embodiment of the present invention provides a connecting rod bearing including a first bearing body surrounding a region of a crank pin and having first grooves formed at both ends of an inner surface, and a second bearing body connecting to the first bearing body, surrounding another region opposite to a region of the crank pin and having second grooves formed at both ends of the inner surface, and having a third groove having a different width from the second groove between the second grooves formed at each end, wherein the second groove and the third groove are characterized in that they are connected to each other through a connecting groove.

Description

Connecting rod bearing and engine system containing the same {Connecting rod bearing and engine system containing the same}

The present invention relates to a connecting rod bearing and an engine system including the same.

Generally, connecting rod bearings are installed on the crank pin of the crankshaft to support and smoothly rotate the crankshaft of the engine. At this time, the connecting rod bearing receives a high load from the piston and comes into contact with the crankshaft that rotates at a high speed, so lubricating oil discharged from the oil pump is supplied to ensure the durability and stability of the connecting rod bearing.

Specifically, the lubricating oil is supplied from the main journal of the crankshaft and supplied to the connecting rod bearing through the crank pin. The connecting rod bearing applied to the marine engine may have a groove formed in the inner circumference to smoothly supply the lubricating oil. As a result, the connecting rod bearing can be continuously supplied with lubricating oil even when the rotation speed of the crankshaft changes rapidly and under high load.

In this case, if the width of the groove formed on the inner surface of the crank shaft is wide, the amount of lubricating oil can be secured, but the contact area between the crank pin and the connecting rod bearing cannot be secured wide. This causes excessive pressure between the crank pin and the connecting rod bearing, which causes a problem of reduced durability stability.

In addition, if the width of the groove formed on the inner surface of the crank shaft is narrow, a wide contact surface area between the crank pin and the connecting rod bearing can be secured, but the supply of lubricating oil cannot be secured. As a result, there is a problem in that the oil film temperature between the crank pin and the connecting rod bearing rapidly increases, resulting in a decrease in the durability of the connecting rod bearing.

Previously, there was no technology development for the shape of a groove in a connecting rod bearing that could simultaneously secure a sufficient amount of lubricating oil supply and a sufficient contact area of the connecting rod bearing, so there was a problem that it was difficult to secure the durability of the connecting rod bearing. In relation to this, there is a lack of research on the shape of the groove that affects the amount of lubricating oil supply or the minimum oil film thickness formed in the connecting rod bearing.

The technical problem to be achieved by the present invention is to provide a connecting rod bearing which can improve the durability of an engine and increase the performance of the engine by reducing the influence of an oil bore by forming grooves with different widths on the inner surface of the bearing body.

One aspect of the present invention provides a connecting rod bearing, comprising: a first bearing body surrounding one area of a crank pin and having first grooves formed at both ends of an inner surface; and a second bearing body connecting to the first bearing body, the second bearing body surrounding another area opposite to the one area of the crank pin and having second grooves formed at both ends of the inner surface, and a third groove having a different width from the second groove formed between the second grooves formed at each of the two ends; wherein the second groove and the third groove are characterized in that they are connected to each other through a connecting groove.

Additionally, the width of the second groove may be formed to be relatively narrower than the width of the third groove.

Additionally, the width of the third groove may be formed to be 1.5 to 2.5 times greater than the width of the second groove.

Additionally, the width of the connecting groove may linearly increase from one side connected to the second groove to the other side connected to the third groove.

Additionally, the side surface of the connecting groove may be formed into a curved surface.

Additionally, the depth of the second groove and the depth of the third groove can be formed to be the same.

In addition, the second groove and the third groove may be formed to extend along the circumferential direction of the second bearing body and may be formed in the middle portion based on the width direction on the inner peripheral surface of the second bearing body.

Additionally, the connecting groove may be formed in a shape in which the second groove and the third groove overlap.

Additionally, on the connecting groove, the sum of the depth of the second groove and the depth of the third groove may be constant.

Based on the rotation axis of the above connecting rod bearing, the angle formed by both ends of the above connecting groove may be 10° or more and 20° or less.

A connecting rod bearing according to one embodiment of the present invention has grooves formed on an inner surface with different widths and connecting grooves connecting grooves having different widths, thereby reducing the influence of an oil bore, thereby improving the durability and performance of an engine.

FIG. 1 is a drawing illustrating an engine system in which a connecting rod bearing according to one embodiment of the present invention is installed.
FIG. 2 is an exploded view of a connecting rod and a connecting rod bearing according to one embodiment of the present invention.
FIG. 3 is a perspective view of a connecting rod bearing according to one embodiment of the present invention.
FIG. 4 is a perspective view of a second bearing body according to one embodiment of the present invention.
Figure 5 is a development view of the inner circumference of a second bearing body according to one embodiment of the present invention.
Figure 6 is a side view of a second bearing body according to one embodiment of the present invention.
Figure 7 is a perspective view of a second bearing body according to another embodiment of the present invention.
Figure 8 is a development view of the inner circumference of a second bearing body according to another embodiment of the present invention.
FIG. 9 is a perspective view of a second bearing body according to another embodiment of the present invention.
Figure 10 is a development view of the inner circumference of a second bearing body according to another embodiment of the present invention.
FIG. 11 is a drawing illustrating the relationship between the minimum oil film thickness formed in a connecting rod bearing according to embodiments of the present invention and the rotation angle of the crank.

The present invention can be modified in various ways and has various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. The effects and features of the present invention and the methods for achieving them will become clear with reference to the embodiments described in detail below together with the drawings. However, the present invention is not limited to the embodiments disclosed below, and can be implemented in various forms.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. When describing with reference to the drawings, identical or corresponding components are given the same drawing reference numerals and redundant descriptions thereof are omitted.

In the examples below, singular expressions include plural expressions unless the context clearly indicates otherwise.

In the examples below, terms such as “include” or “have” mean that a feature or component described in the specification is present, and do not exclude in advance the possibility that one or more other features or components may be added.

In some embodiments, where the implementation is otherwise feasible, a particular process sequence may be performed in a different order than the one described. For example, two processes described in succession may be performed substantially simultaneously, or in a reverse order from the one described.

In the drawings, the sizes of components may be exaggerated or reduced for convenience of explanation. For example, the sizes and thicknesses of each component shown in the drawings are arbitrarily shown for convenience of explanation, and therefore the following embodiments are not necessarily limited to what is shown.

In the description of each component, when it is described as being formed on or under, on and under include both those formed directly or through the intervention of other components, and the criteria for on and under are explained based on the drawings.

FIG. 1 is a drawing illustrating an engine system in which a connecting rod bearing according to one embodiment of the present invention is installed. FIG. 2 is an exploded view of a connecting rod and a connecting rod bearing according to one embodiment of the present invention. FIG. 3 is a perspective view of a connecting rod bearing according to one embodiment of the present invention. FIG. 4 is a perspective view of a second bearing body according to one embodiment of the present invention. FIG. 5 is a developed view of an inner circumferential surface of a second bearing body according to one embodiment of the present invention. FIG. 6 is a side view of a second bearing body according to one embodiment of the present invention.

In this specification, the engine system (1) may be interpreted as an internal combustion engine applied to a ship, but is not limited thereto, and may be interpreted as various devices capable of converting explosive power generated from a piston into mechanical energy, such as a means of transportation, a means of generating power, a generator, etc.

Referring to FIG. 1, the engine system (1) may include a connecting rod (10), a crank shaft (20), a piston (30), and a connecting rod bearing (100).

The connecting rod (10) may have one end connected to a piston (30), and the other end opposite to said one end connected to a crankshaft (20), specifically, a crank pin (25). As a result, energy generated in the combustion chamber of the piston (30) may be transmitted to the crankshaft (20).

Referring to FIG. 2, the connecting rod (10) may include a first rod body (11) and a second rod body (15).

The first rod body (11) can have one end connected to a piston (30), and the other end opposite to the one end can be connected to the second rod body (15).

A connecting rod bearing (100) according to one embodiment of the present invention may be placed between the first rod body (11) and the second rod body (15).

The first rod body (11) and the second rod body (15) can be detachably connected to each other. Accordingly, after the connecting rod bearing (100) is connected to the crank pin (25), the inner surface of the first rod body (11) and the second rod body (15) are connected so that they come into contact with the outer surface of the connecting rod bearing (100), thereby easily connecting the crank shaft (20) and the connecting rod (10).

Referring to FIG. 1, the crank shaft (20) receives power from the connecting rod (10) and rotates around a preset axis, and may include a main journal (21) and a crank pin (25).

The main journal (21) forms the rotation axis of the crank shaft (20) and can be formed in a cylindrical shape extending along the preset axis.

The crank pin (25) is a part that is connected to the connecting rod (10) through the connecting rod bearing (100), and can be formed in a cylindrical shape extending along an axis parallel to the preset axis.

Due to this, the connecting rod (10) can transmit the power generated from the piston (30) to the crank pin (25), and as the crank pin (25) receives the power, torque is generated in the main journal (21), so that it can rotate around the preset axis.

The piston (30) is applied in various structures to conventional internal combustion engines, so a detailed description of the internal structure and operating principle of the piston (30) is omitted.

Referring to FIGS. 1 to 3, a connecting rod bearing (100) according to one embodiment of the present invention can make surface contact with the inner surface of the connecting rod (10) and the outer surface of the crank pin (25), respectively.

Referring to FIG. 2, a connecting rod bearing (100) according to one embodiment of the present invention can be in surface contact with the inner surface of a connecting rod (10), specifically, the first rod body (11) and the second rod body (15), along the outer circumference thereof.

Specifically, the outer surface of the connecting rod bearing (100) can receive power from the connecting rod (10) by making surface contact with the inner surface of the connecting rod (10), and the inner surface of the connecting rod bearing (100) can transmit power to the crank shaft (20) by making surface contact with the outer surface of the crank pin (25).

The connecting rod bearing (100) provides a path for lubricating oil to flow from the crank shaft (20) to the connecting rod (10), and can play a role in reducing friction between the connecting rod (10) and the crank shaft (20).

First to third grooves (111, 151, 152) may be formed on the inner surface of the connecting rod bearing (100), and lubricating oil provided from the crank shaft (20) may flow between the connecting rod bearing (100) and the crank pin (25) to form an oil film.

In addition, the lubricating oil positioned between the connecting rod bearing (100) and the crank pin (25) is guided along a movement path through the first to third grooves (111, 151, 152) and can be discharged toward the connecting rod (10) through the first and second discharge holes (110h, 150h).

This allows the lubricating oil to flow from the crankshaft (20) to the connecting rod (10) via the connecting rod bearing (100), thereby minimizing friction between components of the engine system (1) that operates at high speed, thereby ensuring durability and increasing engine efficiency.

The lubricating oil flowing between the connecting rod bearing (100) and the crank pin (25) must form an oil film of an appropriate thickness to minimize the friction between the connecting rod bearing (100) and the crank pin (25), and a sufficient amount of lubricating oil must be discharged through the first and second discharge holes (110h, 150h) that are connected to the connecting rod (10) to minimize the friction between the remaining components of the engine system (1).

In this way, in order to secure an appropriate lubricating oil film thickness and lubricating oil discharge amount, the shape of the groove (111, 151, 152, 153) formed on the inner surface of the connecting rod bearing (100) can be an important design variable.

Hereinafter, a connecting rod bearing (100) according to embodiments of the present invention for securing an appropriate lubricating oil film thickness and a lubricating oil discharge amount will be described in detail.

Referring to FIGS. 2 and 3, a connecting rod bearing (100) according to one embodiment of the present invention may include a first bearing body (110) and a second bearing body (150).

The first bearing body (110) and the second bearing body (150) are connectable, and specifically, both ends of the first bearing body (110) and both ends of the second bearing body (150) are connected so as to face each other, thereby forming a journal bearing with a preset axis as the rotation axis (AX).

Referring to FIG. 2, the first bearing body (110) according to one embodiment of the present invention may be formed in a half cylinder tube shape having a preset radius.

The inner diameter of the first bearing body (110) may be formed to be the same as the inner diameter of the second bearing body (150), and the outer diameter of the first bearing body (110) may be formed to be the same as the outer diameter of the second bearing body (150).

The first bearing body (110) can be arranged to be rotatable coaxially with the rotation axis (AX) of the second bearing body (150), and the width of the first bearing body (110) can be formed to be the same as the width (W0) of the second bearing body (150).

The thickness of the first bearing body (110) may be formed to be the same as the thickness of the second bearing body (150), and may be formed to be greater than the depth (Dp1) of the first groove (111) to be described later.

A first bearing body (110) according to one embodiment of the present invention surrounds one area of a crank pin (25), and a first groove (111) may be formed at both ends of the inner circumferential surface.

In one embodiment, the above-mentioned area of the crank pin (25) may correspond to one side (upper side based on FIG. 2) of the outer surface of the crank pin (25), and the first bearing body (110) may correspond to the upper shell of the connecting rod bearing (100).

As an optional embodiment, the above-described one area of the crank pin (25) may correspond to the other side (lower side based on FIG. 2) area opposite to the above-described one side of the crank pin (25), and the first bearing body (110) may correspond to the lower shell of the connecting rod bearing (100). In this case, the width (W2) of the second groove (151) of the second bearing body (150) forming the upper shell may be formed to be wider than the width (W3) of the third groove (152).

Referring to FIGS. 2 and 3, the first discharge hole (110h) formed in the first bearing body (110) provides a path for lubricating oil to flow from the inside of the first bearing body (110) to the connecting rod (10), and may be formed in the shape of a hole that connects the inside and outside of the first bearing body (110).

A plurality of first discharge holes (110h) may be formed in the first bearing body (110), and the longitudinal central axis of each of the plurality of first discharge holes (110h) may intersect the rotation axis (AX) of the first bearing body (110).

As an example, the first discharge hole (110h) may be arranged on the inner surface forming the bottom of the first groove (111) and may be formed along the circumferential direction of the first bearing body (110).

The first discharge holes (110h) can be arranged equiangularly around the rotation axis (AX) of the connecting rod bearing (100).

In one embodiment, the diameter of the first discharge hole (110h) may be formed to be the same as the width (W1) of the first groove (111). However, this is not limited to the first discharge hole (110h), and the diameter of the first discharge hole (110h) may be formed to be relatively smaller than the width (W1) of the first groove (111).

In one embodiment, the diameter of the first discharge hole (110h) may be the same as the diameter of the second discharge hole (150h).

As an optional embodiment, the diameter of the first discharge hole (110h) may be formed to be the same as the diameter of the second discharge hole (150h) located on the inner surface of the second groove (151), and may be formed to be relatively smaller than the diameter of the second discharge hole (150h) located on the inner surface of the third groove (152).

Referring to FIG. 3, on the inner surface of the first bearing body (110) according to one embodiment of the present invention, a first groove (111) may be formed in the shape of a recessed portion extending along the circumferential direction of the first bearing body (110).

The first groove (111) may be formed at each end of the inner surface of the first bearing body (110). Specifically, one end of the first groove (111) may be located at an end of the first bearing body (110), and the one end of the first groove (111) may be in communication with the second groove (151) formed at each end of the second bearing body (150).

The angle formed by both ends of the first groove (111) with respect to the rotation axis (AX) of the connecting rod bearing (100) ) may be 10° or more and 40° or less, and more preferably 17.5° or more and 30° or less.

As an example, the length (L1) of each of the first grooves (111) located at both ends of the inner surface of the first bearing body (110) may follow the following mathematical expression 1.

[Mathematical Formula 1]

Here may be 10° or more and 40° or less, and more preferably 17.5° or more and 30° or less.

Referring to FIG. 3 and FIG. 6, the depth (Dp1) of the first groove (111) may be formed to become gradually shallower from both ends of the first bearing body (110) toward the center. Specifically, the depth (Dp1) of the first groove (111) in an area adjacent to an end of the first bearing body (110) may be formed to be relatively deeper than the depth of the first groove (111) in a relatively distant area of the first bearing body (110).

This has the effect of facilitating the flow of lubricating oil between the connecting rod bearing (100) and the crank pin (25) into the first discharge hole (110h) along the inner surface of the first groove (111) that gradually deepens.

Referring to FIG. 3, the width (W1) of the first groove (111) can be formed to be the same as the width (W2) of the second groove (151).

As an example, the first groove (111) may be formed in a shape with a constant width along the circumferential direction of the first bearing body (110).

As an optional embodiment, the width (W1) of the first groove (111) may be formed differently along the circumferential direction of the first bearing body (110). Specifically, the width (W1) of the first groove (111) may be formed to become gradually wider from the end side to the center side of the first bearing body (110).

That is, the width of a region of the first groove (111) adjacent to the end of the first bearing body (110) can be formed to be relatively narrower than the width of a region of the first groove (111) relatively far from the end of the first bearing body (110).

Due to this, the lubricant located between the connecting rod bearing (100) and the crank pin (25) flows into the inside of the first groove (111) through one side of the first groove (111) with a wide width, so that a sufficient amount of lubricant can be discharged through the first discharge hole (110h).

However, it is not limited to this, and the width (W1) of the first groove (111) may be formed in a shape that gradually narrows from the end side to the center side of the first bearing body (110).

According to one embodiment of the present invention, a first groove (111) may be formed in the middle portion of the inner circumferential surface of the first bearing body (110) in the width direction.

Referring to FIGS. 2 to 6, the second bearing body (150) according to one embodiment of the present invention may be formed in a semi-cylindrical tube shape having a preset radius.

A second bearing body (150) according to one embodiment of the present invention surrounds one area of the crank pin (25) that is opposite to the area surrounded by the first bearing body (110), and a second groove (151), a third groove (152), and a connecting groove (153) may be formed on the inner surface.

The inner diameter of the second bearing body (150) may be formed to be the same as the inner diameter of the first bearing body (110), and the outer diameter of the second bearing body (150) may be formed to be the same as the outer diameter of the first bearing body (110).

The second bearing body (150) can be arranged to be rotatable about the same axis as the rotation axis (AX) of the first bearing body (110), and the width (W0) of the second bearing body (150) can be formed to be the same as the width of the first bearing body (110).

The thickness of the second bearing body (150) may be formed to be the same as the thickness of the first bearing body (110), and may be formed to be greater than the depth of each of the second groove (151), third groove (152), and connecting groove (153) to be described later.

A second bearing body (150) according to one embodiment of the present invention surrounds one area of a crank pin (25), and a second groove (151) may be formed at both ends of the inner circumferential surface.

In one embodiment, the above-mentioned area of the crank pin (25) may correspond to one side (lower side based on FIG. 2) of the outer surface of the crank pin (25), and the second bearing body (150) may correspond to the lower shell of the connecting rod bearing (100).

As an optional embodiment, the above-described one area of the crank pin (25) may correspond to the other side (upper side as shown in FIG. 2) area opposite to the above-described one side of the crank pin (25), and the second bearing body (150) may correspond to the upper shell of the connecting rod bearing (100). In this case, the width (W2) of the second groove (151) of the second bearing body (150) forming the upper shell may be formed to be wider than the width (W3) of the third groove (152).

Referring to FIGS. 2 to 5, the second discharge hole (150h) provides a path for lubricating oil to flow from the inside of the second bearing body (150) toward the connecting rod (10), and may be formed in the shape of a hole that connects the inside and outside of the second bearing body (150).

A plurality of second discharge holes (150h) may be formed in the second bearing body (150), and the longitudinal central axis of each of the plurality of second discharge holes (150h) may intersect the rotation axis (AX) of the second bearing body (150).

As an example, the second discharge hole (150h) may be arranged on the inner surface forming the bottom of the second groove (151), the third groove (152) and the connecting groove (153), and may be formed along the circumferential direction of the second bearing body (150).

The second discharge holes (150h) can be arranged equiangularly around the rotation axis (AX) of the connecting rod bearing (100).

As an example, the diameter of the second discharge hole (150h) may be formed to be the same as the width (W2) of the second groove (151).

As an optional embodiment, the diameter of the second discharge hole (150h) formed on the inner surface of the second groove (151) may be formed to be the same as the width (W2) of the second groove (151), and the diameter of the second discharge hole (150h) formed on the inner surface of the third groove (152) may be formed to be the same as the width (W3) of the third groove (152).

In addition, the diameter of the second discharge hole (150h) formed on the inner surface of the connecting groove (153) may be formed to be larger than the diameter of the second discharge hole (150h) formed on the inner surface of the second groove (151) and smaller than the diameter of the second discharge hole (150h) formed on the inner surface of the third groove (152).

Referring to FIGS. 3 to 6, a second groove (151) according to one embodiment of the present invention may be formed at both ends of the inner circumferential surface of the second bearing body (150).

In addition, a third groove (152) is formed between the second grooves (151) formed at each end of the inner surface of the second bearing body (150), and the third groove (152) of the second groove (151) can be connected through a connecting groove (153).

Specifically, one end of the second groove (151) may be located at an end of the second bearing body (150), and the other end of the second groove (151) opposite to the one end may be connected to the third groove (152) through a connecting groove (153).

The angle formed by both ends of the second groove (151) with respect to the rotation axis (AX) of the connecting rod bearing (100) ) may be 25° or more and 60° or less, and more preferably 32.5° or more and 54.5° or less.

As an example, the length (L2) of each of the second grooves (151) located at both ends of the inner surface of the second bearing body (150) may follow the following mathematical expression 2.

[Mathematical formula 2]

Here may be 25° or more and 60° or less, and more preferably 32.5° or more and 54.5° or less.

Referring to FIG. 3, the width (W2) of the second groove (151) can be formed to be the same as the width (W1) of the first groove (111).

As an example, the second groove (151) may be formed with a shape having a constant width along the circumferential direction of the second bearing body (150).

As an optional embodiment, the width (W2) of the second groove (151) may be formed differently along the circumferential direction of the second bearing body (150).

Specifically, the width (W2) of the second groove (151) can be formed in a shape that gradually widens from the end side of the second bearing body (150) toward the third groove (152).

That is, the width of one area of the second groove (151) adjacent to the end of the second bearing body (150) can be formed to be relatively narrower than the width of one area of the second groove (151) adjacent to the third groove (152).

As an optional embodiment, the width (W2) of the second groove (151) may be formed in a shape that gradually narrows from the end side of the second bearing body (150) toward the third groove (152).

That is, the width of one area of the second groove (151) adjacent to the end of the second bearing body (150) can be formed to be relatively wider than the width of one area of the second groove (151) adjacent to the third groove (152).

According to one embodiment of the present invention, a second groove (151) is formed to extend along the circumferential direction of the second bearing body (150) and may be formed in the middle portion based on the width direction on the inner surface of the second bearing body (150).

Referring to FIGS. 3 to 5, the width (W2) of the second groove (151) according to one embodiment of the present invention may be formed to be relatively narrower than the width (W3) of the third groove (152).

Specifically, the width (W2) of the second groove (151) can be formed to be 2/5 to 2/3 of the width (W3) of the third groove (152).

Referring to FIG. 3, FIG. 4, and FIG. 6, the depth (Dp2) of the second groove (151) can be formed in a shape with a constant depth along the circumferential direction of the second bearing body (150).

In one embodiment, the depth (Dp2) of the second groove (151) may be formed to be the same as the depth (Dp3) of the third groove (152) and the depth of the connecting groove (153).

As an optional embodiment, the depth (Dp2) of the second groove (151) may be formed relatively deeper than the depth (Dp3) of the third groove (152). Specifically, the depth (Dp2) of the second groove (151) may be formed deeper than the depth of the connecting groove (153), and the depth of the connecting groove (153) may be formed relatively deeper than the depth (Dp3) of the third groove (152).

One or more second discharge holes (150h) may be formed in the shape of a hole on the inner surface forming the bottom of the second groove (151).

As a result, the lubricant located between the connecting rod bearing (100) and the crank pin (25) is discharged through the second groove (151) to the second discharge hole (150h), thereby providing the effect of supplying the lubricant to the connecting rod (10) that is connected to the second discharge hole (150h).

Referring to FIGS. 3 to 6, a third groove (152) according to one embodiment of the present invention may be formed between second grooves (151) formed at each end of the inner surface of the second bearing body (150).

One end of the third groove (152) can be connected to the second groove (151) adjacent to one end (the right end as shown in FIG. 4) of the second bearing body (150), and the other end of the third groove (152) opposite to the one end can be connected to the second groove (151) adjacent to the other end (the left end as shown in FIG. 4) of the second bearing body (150).

The third groove (152) can be connected to the second groove (151) through a connecting groove (153), and specifically, a connecting groove (153) can be positioned between the second groove (151) and the third groove (152) formed at each end of the inner surface of the second bearing body (150).

The angle formed by both ends of the third groove (152) with respect to the rotation axis (AX) of the connecting rod bearing (100) ) may be 90° or more and 140° or less, more preferably 105° or more and 130° or less.

As an example, the length (L3) of the third groove (152) located between the second grooves (151) formed at each end of the second bearing body (150) may follow the following mathematical expression 3.

[Mathematical Formula 3]

Here may be 90° or more and 140° or less, more preferably 105° or more and 130° or less.

Referring to FIG. 3, the width (W3) of the third groove (152) can be formed to be relatively larger than the width (W2) of the second groove (151).

Specifically, the width (W3) of the third groove (152) may be formed to be 1.5 to 2.5 times the width (W2) of the second groove (151), more preferably 1.7 to 2.2 times the width, and even more preferably 2 times the width.

As an example, the third groove (152) may be formed with a shape having a constant width along the circumferential direction of the second bearing body (150).

As an optional embodiment, the width (W3) of the third groove (152) may be formed differently along the circumferential direction of the second bearing body (150).

Specifically, the width (W3) of the third groove (152) may be formed to gradually widen from the end side to the center side of the second bearing body (150). That is, the width of a region of the third groove (152) adjacent to the second groove (151) may be formed to be relatively narrower than the width of a region of the third groove (152) relatively far from the second groove (151).

As an optional embodiment, the width (W3) of the third groove (152) may be formed to gradually narrow from the end side to the center side of the second bearing body (150). That is, the width of a region of the third groove (152) adjacent to the second groove (151) may be formed to be relatively wider than the width of a region of the third groove (152) relatively far from the second groove (151).

According to one embodiment of the present invention, the third groove (152) is formed to extend along the circumferential direction of the second bearing body (150) and may be formed in the middle portion based on the width direction on the inner surface of the second bearing body (150).

Referring to FIG. 3, FIG. 4, and FIG. 6, the depth (Dp3) of the third groove (152) can be formed in a shape with a constant depth along the circumferential direction of the second bearing body (150).

In one embodiment, the depth (Dp3) of the third groove (152) may be formed to be the same as the depth (Dp2) of the second groove (151).

As an optional embodiment, the depth (Dp3) of the third groove (152) may be formed relatively shallower than the depth (Dp2) of the second groove (151).

Specifically, the depth (Dp3) of the third groove (152) may be formed shallower than the depth of the connecting groove (153), and the depth of the connecting groove (153) may be formed relatively shallower than the depth (Dp2) of the second groove (151).

One or more second discharge holes (150h) may be formed in the shape of a hole on the inner surface forming the bottom of the third groove (152). As a result, lubricating oil located between the connecting rod bearing (100) and the crank pin (25) is discharged through the third groove (152) to the second discharge hole (150h), so that lubricating oil can be supplied to the connecting rod (10) that is connected to the second discharge hole (150h).

Referring to FIGS. 3 to 6, a connecting groove (153) according to one embodiment of the present invention is positioned between the second groove (151) and the third groove (152), and may be formed in the shape of a groove portion that connects the second groove (151) and the third groove (152).

According to one embodiment of the present invention, the longitudinal central axis of the connecting groove (153) may coincide with at least one of the longitudinal central axis of the second groove (151) or the longitudinal central axis of the third groove (152).

The connecting groove (153) can be formed in a shape in which one end is connected to the second groove (151) and the other end opposite to the one end is connected to the third groove (152). The width of the one end of the connecting groove (153) can be the same as the width (W2) of the second groove (151), and the width of the other end of the connecting groove (153) can be formed the same as the width (W3) of the third groove (152).

Referring to FIGS. 3 to 5, the width (W4) of the connecting groove (153) according to one embodiment of the present invention may be formed in a shape that linearly increases from one side connected to the second groove (151) to the other side connected to the third groove (152).

One side forming the side of the connecting groove (153) may be formed as a flat surface. Specifically, the side of the connecting groove (153) may be formed as a plane that is perpendicular to the radial direction of the second bearing body (150) and forms a preset angle with the circumferential direction of the second bearing body (150).

One or more second discharge holes (150h) may be formed on the inner surface forming the bottom of the connecting groove (153).

As an example, the diameter of the second discharge hole (150h) formed on the inner surface of the connecting groove (153) may be formed to be the same as the diameter of the second discharge hole (150h) formed on the inner surface of the second groove (151).

As an optional embodiment, the diameter of the second discharge hole (150h) formed on the inner surface of the connecting groove (153) may be formed to be the same as the diameter of the second discharge hole (150h) formed on the inner surface of the third groove (152).

As an optional embodiment, the diameter of the second discharge hole (150h) formed on the inner surface of the connecting groove (153) may be formed to be larger than the diameter of the second discharge hole (150h) formed on the inner surface of the second groove (151) and smaller than the diameter of the second discharge hole (150h) formed on the inner surface of the third groove (152).

As an optional embodiment, a plurality of second discharge holes (150h) formed on the inner surface of the connecting groove (153) may be formed along the circumferential direction of the second bearing body (150), and the diameters of the plurality of second discharge holes (150h) may gradually increase from the second groove (151) to the third groove (152).

The angle formed by both ends of the connecting groove (153) with respect to the rotation axis (AX) of the connecting rod bearing (100) ) may be 10° or more and 20° or less, and more preferably 12° or more and 17° or less.

As an example, the length (L4) of the connecting groove (153) located between the second groove (151) and the third groove (152) may follow the following mathematical expression 4.

[Mathematical formula 4]

Here may be 10° or more and 20° or less, and more preferably 12° or more and 17° or less.

The angle formed between one end of the second bearing body (150) and the end of the connecting groove (153) adjacent to the one end of the second bearing body (150) may be 25° or more and 60° or less with respect to the rotation axis (AX) of the connecting rod bearing (100), and more preferably 32.5° or more and 54.5° or less.

Hereinafter, a connecting rod bearing according to another embodiment of the present invention will be described. A connecting rod bearing according to another embodiment of the present invention may include a first bearing body and a second bearing body (150`).

A connecting rod bearing according to another embodiment of the present invention has the same configuration and effect as the connecting rod bearing (100) according to one embodiment of the present invention, except that the side surface of the connecting groove (153`) is formed as a curved surface in relation to the second bearing body (150`), so a detailed description is omitted to the extent that it overlaps therewith.

Fig. 7 is a perspective view of a second bearing body according to another embodiment of the present invention. Fig. 8 is a development view of the inner circumference of a second bearing body according to another embodiment of the present invention.

Referring to FIGS. 7 and 8, a connecting groove (153`) formed in a second bearing body (150`) according to another embodiment of the present invention is located between the second groove (151`) and the third groove (152`), and may be formed in the shape of a groove portion that connects the second groove (151`) and the third groove (152`).

According to another embodiment of the present invention, the longitudinal central axis of the connecting groove (153`) may coincide with at least one of the longitudinal central axis of the second groove (151`) or the longitudinal central axis of the third groove (152`).

A connecting groove (153`) according to another embodiment of the present invention may be formed in a shape in which one end is connected to a second groove (151`) and the other end opposite to the one end is connected to a third groove (152`). The width of the one end of the connecting groove (153`) may be the same as the width (W2) of the second groove (151`), and the width of the other end of the connecting groove (153`) may be formed the same as the width (W3) of the third groove (152`).

Referring to FIGS. 7 and 8, the width (W4) of a connecting groove (153`) according to another embodiment of the present invention may be formed in a shape that non-linearly increases from one side connected to the second groove (151`) to the other side connected to the third groove (152`).

One side forming the side surface of the connecting groove (153`) according to another embodiment of the present invention may be formed as a curved surface. Specifically, the side surface of the connecting groove (153`) may be formed as a curved surface that is parallel to the radial direction of the second bearing body (150`) and is formed to be rounded based on the circumferential direction of the second bearing body (150`).

The side portion of the connecting groove (153`) adjacent to the second groove (151`) may be formed in a convex shape toward the longitudinal central axis of the connecting groove (153`), and the side portion of the connecting groove (153`) adjacent to the third groove (152`) may be formed in a concave shape toward the longitudinal central axis of the connecting groove (153`).

As an optional embodiment, a side portion of a connecting groove (153`) adjacent to the second groove (151`) may be formed in a convex shape toward the longitudinal central axis of the connecting groove (153`), a side portion of a connecting groove (153`) adjacent to the third groove (152`) may be formed in a concave shape toward the longitudinal central axis of the connecting groove (153`), and a side portion of the connecting groove (153`) located between the convex portion and the concave portion may be formed in a flat surface.

According to another embodiment of the present invention, one or more second discharge holes (150`h) may be formed on the inner surface forming the bottom of the connecting groove (153`).

According to another embodiment of the present invention, the diameter of the second discharge hole (150`h) formed on the inner surface of the connecting groove (153) may be formed to be the same as the diameter of the second discharge hole (150`h) formed on the inner surface of the second groove (151`).

As an optional embodiment, the diameter of the second discharge hole (150`h) formed on the inner surface of the connecting groove (153`) may be formed to be the same as the diameter of the second discharge hole (150`h) formed on the inner surface of the third groove (152`).

As an optional embodiment, the diameter of the second discharge hole (150`h) formed on the inner surface of the connecting groove (153`) may be formed to be larger than the diameter of the second discharge hole (150`h) formed on the inner surface of the second groove (151`) and smaller than the diameter of the second discharge hole (150`h) formed on the inner surface of the third groove (152`).

As an optional embodiment, a plurality of second discharge holes (150`h) formed on the inner surface of the connecting groove (153`) may be formed along the circumferential direction of the second bearing body (150`), and the diameters of the plurality of second discharge holes (150`h) may gradually increase from the second groove (151`) side to the third groove (152`).

The angle formed by both ends of the connecting groove (153`) based on the rotation axis (AX) of the connecting rod bearing (100) ) may be 10° or more and 20° or less, and more preferably 12° or more and 17° or less.

The length (L4) of the connecting groove (153`) according to another embodiment of the present invention can follow the following mathematical expression 5.

[Mathematical Formula 5]

Here may be 10° or more and 20° or less, and more preferably 12° or more and 17° or less.

The angle formed between one end of the second bearing body (150`) and the end of the connecting groove (153`) adjacent to the one end of the second bearing body (150`) may be 25° or more and 60° or less with respect to the rotation axis (AX) of the connecting rod bearing (100), and more preferably 32.5° or more and 54.5° or less.

Hereinafter, a connecting rod bearing according to another embodiment of the present invention will be described. A connecting rod bearing according to another embodiment of the present invention may include a first bearing body and a second bearing body (150``).

A connecting rod bearing according to another embodiment of the present invention has the same remaining configuration and effect as that of the connecting rod bearing (100) according to one embodiment of the present invention, except that the side surface of the connecting groove (153`) is formed as a curved surface in relation to the second bearing body (150``), and that the connecting groove (153``) is formed in a shape in which the second groove (151``) and the third groove (152``) overlap each other. Therefore, a detailed description thereof will be omitted to the extent that it overlaps therewith.

Fig. 9 is a perspective view of a second bearing body according to another embodiment of the present invention. Fig. 10 is a development view of the inner circumference of a second bearing body according to another embodiment of the present invention.

Referring to FIGS. 9 and 10, a connecting groove (153``) formed in a second bearing body (150``) according to another embodiment of the present invention is positioned between the second groove (151``) and the third groove (152``), and may be formed in the shape of a groove portion that connects the second groove (151``) and the third groove (152``).

According to another embodiment of the present invention, the longitudinal central axis of the connecting groove (153``) may coincide with at least one of the longitudinal central axis of the second groove (151``) or the longitudinal central axis of the third groove (152``).

According to another embodiment of the present invention, a connecting groove (153``) may be formed in a shape in which one end is connected to a second groove (151``) and the other end opposite to the one end is connected to a third groove (152``).

According to another embodiment of the present invention, a connecting groove (153``) may be formed in a shape in which the second groove (151``) and the third groove (152``) overlap. Hereinafter, the 'overlapping shape' will be described in detail.

Referring to FIG. 9, a connecting groove (153``) according to another embodiment of the present invention may have a shape in which a groove portion formed in a shape in which a second groove (151``) extends toward a third groove (152``) along the circumferential direction of the second bearing body (150``) and a groove portion formed in a shape in which a third groove (152``) extends toward the second groove (151``) along the circumferential direction of the second bearing body (150``) overlap each other.

The connecting groove (153``) can extend from one side (‘one side’ means the part where the second groove (151``) and the connecting groove (153``) are connected) along the circumferential direction of the second bearing body (150``) to the other side (‘the other side’ means the part where the third groove (152``) and the connecting groove (153``) are connected).

According to another embodiment of the present invention, a connecting groove (153``) may be formed in a shape in which a groove portion (hereinafter referred to as a 'first groove portion (153``a)') that extends from one side to the other side and has the same width as the second groove (151``) and a gradually decreasing depth is formed, and a groove portion (hereinafter referred to as a 'second groove portion (153``b)') that extends from the other side to one side and has the same width as the third groove (152``) and a gradually decreasing depth is formed.

Specifically, the depth of the first groove (153``a) may relatively decrease from one side of the connecting groove (153``) connected to the second groove (151``) to the other side of the connecting groove (153``) connected to the third groove (152``).

In addition, the depth of the second groove (153``b) may relatively decrease from the other side of the connecting groove (153``) connected to the third groove (152``) to one side of the connecting groove (153``) connected to the second groove (151``).

The depth of one side of the first groove (153``a) can be formed to be the same as the depth (Dp2) of the second groove (151``), and the depth of the other side of the first groove (153``a) can be 0 or converge to 0.

The depth of the other side of the second groove (153``b) may be formed to be the same as the depth (Dp3) of the third groove (152``), and the depth of one side of the second groove (153``b) may be 0 or converge to 0.

The longitudinal central axis of the first groove portion (153``a) may be identical to the longitudinal central axis of the second groove portion (153``b).

The longitudinal central axis of the first groove (153``a) may coincide with the longitudinal central axis of the second groove (151``), and the longitudinal central axis of the second groove (153``b) may coincide with the longitudinal central axis of the third groove (152``).

Specifically, the longitudinal central axis of the first groove portion (153``a) and the longitudinal central axis of the second groove portion (153``b) can be formed in the middle portion based on the width direction on the inner surface of the second bearing body (150``).

Referring to FIG. 9, according to another embodiment of the present invention, the sum of the depth (Dp2) of the second groove on the connecting groove (153``) and the depth (Dp3) of the third groove on the connecting groove (153``) may be constant.

The 'second groove on the connecting groove (153``)' can be interpreted as the first groove portion (153``a), and the 'third groove on the connecting groove (153``)' can be interpreted as the second groove portion (153``b).

Referring to FIG. 9, the depth decrease amount of the first groove portion (153``a) that decreases from one side to the other side may be the same as the depth increase amount of the second groove portion (153``b) that increases from one side to the other side.

According to another embodiment of the present invention, one or more second discharge holes (150``h) may be formed on the inner surface forming the bottom of the connecting groove (153``).

According to another embodiment of the present invention, the diameter of the second discharge hole (150``h) formed on the inner surface of the connecting groove (153``) may be formed to be the same as the diameter of the second discharge hole (150``h) formed on the inner surface of the second groove (151``).

According to another embodiment of the present invention, the angle formed by both ends of the connecting groove (153``) may be 10° or more and 20° or less with respect to the rotation axis (AX) of the connecting rod bearing (100), and more preferably 12° or more and 17° or less.

Specifically, the angle formed by one side and the other side of the connecting groove (153``) with respect to the rotation axis (AX) of the connecting rod bearing (100) ) may be 10° or more and 20° or less, and more preferably 12° or more and 17° or less.

The length (L4) of the connecting groove (153``) according to another embodiment of the present invention can follow the following mathematical expression 6.

[Mathematical Formula 6]

Here may be 10° or more and 20° or less, and more preferably 12° or more and 17° or less.

The angle formed between one end of the second bearing body (150``) and one end of the connecting groove (153``) may be 25° or more and 60° or less with respect to the rotation axis (AX) of the connecting rod bearing (100), and more preferably 32.5° or more and 54.5° or less.

Hereinafter, the operating principle and effect of an engine system (1) including a connecting rod bearing according to embodiments of the present invention will be described.

The explanation of the operating principles and methods in this specification in a chronological order is for the convenience of explanation, and the operating principles and methods described below are not limited to the order of explanation and may be performed simultaneously.

Referring to FIG. 1, the engine system (1) may include a piston (30) that converts heat energy generated by combusting an oxidizer into mechanical energy, a connecting rod (10) that transmits power from the piston (30) to a rotating crankshaft (20), a crankshaft (20) that receives power from the connecting rod (10) and rotates along a preset axis, and a connecting rod bearing (100).

Since each component of the engine system (1) is driven at high speed in a high load environment, minimizing the frictional force and applied load between each component becomes a key design goal.

In order to minimize friction between components of the engine system (1), specifically, the connecting rod (10), crank shaft (20), piston (30) and sub-components of each component, lubricating oil is supplied to the engine system (1) and flows along a preset path.

In particular, the connecting rod bearing (100), which receives power from the connecting rod (10) and transmits the power to the crankshaft (20), withstands a high load and frictional force while providing a path for lubricating oil to flow from the crankshaft (20) to the connecting rod (10). In order to facilitate the supply and discharge of the lubricating oil, a groove (111, 151, 152, 153) having a preset shape may be formed on the inner surface of the connecting rod bearing (100).

Lubricating oil is supplied to the connecting rod bearing (100) through an oil bore formed on the outer periphery of the crank shaft (20), specifically, the crank pin (25).

The lubricating oil supplied from the oil bore forms an oil film between the crank pin (25) and the connecting rod bearing (100), thereby reducing the frictional force between the outer surface of the crank pin (25) and the inner surface of the connecting rod bearing (100).

A portion of the lubricating oil supplied from the oil bore forms an oil film between the crank pin (25) and the connecting rod bearing (100), and the remaining portion is discharged through the first to third grooves (111, 151, 152) and the connecting groove (153) formed on the inner surface of the connecting rod bearing (100) to the first and second discharge holes (110h, 150h), and the lubricating oil discharged through the first and second discharge holes (110h, 150h) flows to the connecting rod (10).

This has the effect of reducing the friction between the crank pin (25) and the connecting rod bearing (100) as well as the friction between the lower components of the connecting rod (10) and the piston (30) connected to the connecting rod (10).

A connecting rod bearing (100) according to embodiments of the present invention may include a first bearing body (110) and a second bearing body (150, 150`, 150``) constituting an upper shell and a lower shell of a journal bearing.

On the inner surface of the first bearing body (110) and the second bearing body (150, 150`, 150``), first and second discharge holes (110h, 150h) are formed in the shape of holes that communicate with the inner surface of the connecting rod (10).

In addition, on the inner surface of the first bearing body (110) and the second bearing body (150, 150`, 150``), first to third grooves (111, 151, 152) that guide the movement path of lubricating oil from the oil bore to the first and second discharge holes (110h, 150h) and a connecting groove (153) that connects grooves having different widths can be formed to extend in the circumferential direction.

In general, when the width of the groove formed on the inner surface of the connecting rod bearing (100) is wide, the contact area with the crank pin (25) is relatively reduced, and accordingly, the area where the oil film is formed is also reduced, so sufficient lubrication performance cannot be secured.

However, in a preset area on the inner surface of the connecting rod bearing (100), oil bore interference occurs due to the oil bore of the crank pin (25), and in this area, as the groove width increases, the lubrication performance increases.

The connecting rod bearing (100) according to embodiments of the present invention, specifically, the second bearing body (150, 150`, 150``), includes a second groove (151, 151`, 151``) and a third groove (152, 152`, 152``) formed with different widths in consideration of the oil bore interference effect, thereby having the effect of securing lubrication performance in all sections of the inner surface of the second bearing body (150, 150`, 150``).

Specifically, the second bearing body (150, 150`, 150``) extends in the circumferential direction and includes a second groove (151, 151`, 151``) and a third groove (152, 152`, 152``) formed with different widths, and a connecting groove (153, 153`, 153``) connecting the second groove (151, 151`, 151``) and the third groove (152, 152`, 152``) is formed in the shape of a groove portion in a preset area of the second bearing body (150, 150`, 150``).

Accordingly, a connecting groove (153, 153`, 153``) is formed on an area of the inner surface of the second bearing body (150, 150`, 150``) considering the point in time and area where oil bore interference occurs, thereby providing the effect of securing lubrication performance in all areas of the connecting rod bearing (100) despite the occurrence of the oil bore interference effect.

FIG. 11 is a drawing showing the relationship between the minimum oil film thickness formed in a connecting rod bearing (100) according to embodiments of the present invention and the rotation angle of the crank.

Specifically, FIG. 11 is experimental data comparing the minimum thickness of an oil film formed in a conventional connecting rod bearing and the minimum thickness of an oil film formed in a connecting rod bearing (100) according to embodiments of the present invention as the crank rotation angle changes due to the movement of the piston.

The oil film formed on the connecting rod bearing (100) must be formed thicker than a preset oil film thickness, and if there is a point at which the oil film formed on the connecting rod bearing (100) is formed thinner than the preset oil film thickness, there is a problem in that the performance of the engine system (1), the durability of the engine system (1), and the lubrication performance of the connecting rod bearing (100) deteriorate.

Referring to FIG. 11, the minimum value of the minimum oil film thickness formed in a conventional connecting rod bearing according to the crank rotation angle is lower than the minimum value of the minimum oil film thickness formed in a connecting rod bearing (100) according to embodiments of the present invention.

Specifically, according to experimental data, in a crank rotation angle range of about 380° to 430°, the minimum value of the oil film thickness formed in a conventional connecting rod bearing was measured to be lower than a preset oil film thickness, and the minimum value of the oil film thickness formed in a connecting rod bearing (100) according to embodiments of the present invention was measured to be higher than a preset oil film thickness.

That is, the minimum value of the minimum oil film thickness formed in the connecting rod bearing (100) according to the embodiments of the present invention is lower than the minimum value of the minimum oil film thickness formed in the conventional connecting rod bearing, and therefore, the conventional connecting rod bearing has difficulty in securing engine performance or durability compared to the connecting rod bearing (100) according to the embodiments of the present invention.

In conclusion, the connecting rod bearing (100) according to the embodiments of the present invention reduces the influence of the oil bore by forming a connecting groove (153) connecting grooves (151, 152) having different widths, thereby increasing the minimum value of the oil film thickness that can be formed in the connecting rod bearing (100), thereby securing engine performance and durability regardless of the rotation angle of the crank.

The idea of the present invention should not be limited to the embodiments described above, and not only the scope of the patent claims described below, but also all scopes equivalent to or equivalently modified from the scope of the patent claims are included in the scope of the idea of the present invention.

1: Engine system 10: Connecting rod
11: 1st load body 15: 2nd load body
20: Crankshaft 21: Main journal
25: Crank pin 30: Piston
100: Connecting rod bearing 110: First bearing body
110h: 1st discharge hole 111: 1st groove
150: 2nd bearing body 150h: 2nd discharge hole
151: 2nd groove 152: 3rd groove
153: Connecting groove

Claims (11)

A first bearing body surrounding one area of a crank pin and having a first groove formed at both ends of the inner surface; and
A second bearing body is provided, which surrounds the first region of the crank pin and is opposite to the other region, and is connectable to the first bearing body, and has second grooves formed at both ends of the inner surface, and a third groove having a different width from the second groove is formed between the second grooves formed at each of the two ends;
A connecting rod bearing, characterized in that the second groove and the third groove are connected to each other through a connecting groove. In the first paragraph,
A connecting rod bearing, characterized in that the width of the second groove is formed relatively narrower than the width of the third groove. In the second paragraph,
A connecting rod bearing, characterized in that the width of the third groove is formed to be 1.5 to 2.5 times greater than the width of the second groove. In the second paragraph,
A connecting rod bearing, characterized in that the width of the connecting groove increases linearly from one side connected to the second groove to the other side connected to the third groove. In the second paragraph,
A connecting rod bearing characterized in that the side surface of the above connecting groove is formed into a curved surface. In clause 4 or 5,
A connecting rod bearing, characterized in that the depth of the second groove and the depth of the third groove are formed to be the same. In the second paragraph,
The second groove and the third groove are,
A connecting rod bearing characterized in that it is formed extending along the circumferential direction of the second bearing body and is formed in the middle portion based on the width direction on the inner surface of the second bearing body. In Article 7,
A connecting rod bearing, characterized in that the above connecting groove is formed in a shape in which the second groove and the third groove overlap. In Article 8,
A connecting rod bearing, characterized in that the sum of the depth of the second groove and the depth of the third groove in the above connecting groove is constant. In the first paragraph,
A connecting rod bearing, characterized in that the angle formed by both ends of the connecting groove with respect to the rotation axis of the connecting rod bearing is 10° or more and 20° or less. A piston that reciprocates in a preset direction;
A crankshaft that rotates about a preset axis;
A connecting rod connected to the piston and the crankshaft respectively and transmitting power from the piston to the crankshaft; and
A connecting rod bearing is disposed between the crankshaft and the connecting rod and provides a flow path for lubricating oil moving from the crankshaft to the connecting rod;
An engine system, characterized in that grooves having different widths are formed along the circumferential direction of the connecting rod bearing on the inner surface of the connecting rod bearing.

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