Bearing housing, bearing, piston engine and use of bearing housing
By designing the oil groove with a narrow third intermediate part on the inner surface of the bearing shell, the bearing overload problem caused by uneven wear of crankshafts in the piston engine, realizing more uniform wear and reducing the formation of the spine.
Patent Information
- Application Number
- CN202280097201.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2022-06-22
- Publication Date
- 2025-01-28
AI Technical Summary
In piston engines, uneven wear of the crankshaft pins leads to overload and local wear of the bearing, especially when the piston is at the bottom dead center, the ridges come into contact with the upper half of the bearing, resulting in uneven loads and wear.
Design an improved bearing shell with oil grooves inner surfaces. The oil grooves include the first part of the first, second parts, and the third part of the connection. The third part is narrower than the first and second parts, and extends from the direction of the bearing shell from the axial direction of the bearing shell to reduce the formation of the spine.
Through this design, the wear of the crankshaft sales is more uniform, reducing the continuous non -contact part of the direction of the bearing shell in the direction of the bearing shell, thereby reducing the formation of the spine in the oil tank area and avoiding the overload and local wear of the bearings.
Smart Images
Figure CN119384561A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a bearing shell for connecting a connecting rod of a piston engine to a bearing of a crankshaft as defined in claim 1. The invention also relates to a bearing, a piston engine and the use of the bearing shell. Background Art
[0002] In a piston engine, a piston rod connects each piston to the crankshaft. The bearing that connects the piston rod to the crankshaft is often called the big end bearing.
[0003] A typical big end bearing is a plain bearing comprising two halves arranged around the crankpin of the crankshaft. The bearing is rotationally fixed to the connecting rod and therefore there is a rotational movement between the crankpin and the bearing. An oil film is formed between the inner surface of the bearing and the crankpin.
[0004] The lower half of the big end bearing is usually provided with an oil groove. The upper half of the bearing may have a horizontal surface. The purpose of the oil groove is to facilitate the spreading of the lubricating oil on the bearing surface. The oil groove extends in the middle of the bearing surface along the circumferential direction of the bearing. Figure 3 An example of the lower half of a prior art big end bearing is shown.
[0005] During the use of the engine, the crankpin wears. However, the wear is not uniform. Figure 1 As shown, when the piston is at top dead center, the crankpin wears more at the area forming the lower portion of the crankpin. Even though the lower portion of the crankpin wears unevenly, the area aligned with the oil groove of the bearing experiences less wear than the areas on both sides of the oil groove. Due to uneven wear, a protrusion, i.e., a ridge, may be formed in the middle of the crankpin. The height of the ridge may correspond to the thickness of the oil film. Figure 1 and Figure 2 An enlarged view of such a ridge is shown in an enlarged view of .
[0006] When the piston is near the bottom dead center, Figure 2 In the case shown, the ridge of the crankpin contacts the upper half of the bearing, which can cause problems such as overloading and localized wear of the upper half of the bearing. Problems may also be encountered after a new bearing has been replaced during an overhaul, as the protruding portion of the crankpin contacts the unworn bearing surface and causes uneven loading. Summary of the invention
[0007] The object of the invention is to provide an improved bearing shell for a bearing connecting a connecting rod of a piston engine to a crankshaft. The particular features of the bearing shell according to the invention are given in claim 1. Other objects of the invention are to provide an improved bearing, a piston engine and the use of a bearing shell.
[0008] According to the present invention, the inner surface of the bearing shell is provided with an oil groove, the oil groove includes a first portion, a second portion and a third middle portion connecting the first portion and the second portion, wherein the first portion and the second portion are straight and extend in the circumferential direction of the bearing shell, and wherein the third portion is narrower than the first portion and the second portion, and at least a portion of the third portion extends in a direction deviating from the circumferential direction of the bearing shell along the axial direction of the bearing shell.
[0009] Due to the narrower groove, a larger portion of the bearing shell is in contact with the crankpin, and the crankpin wears more evenly. Since the direction of the third portion is different from the circumferential direction, the continuous non-contact portion in the circumferential direction of the bearing shell can be reduced. This reduces the formation of ridges in the area of the oil groove.
[0010] According to one embodiment of the invention, the third portion is arranged between imaginary extensions of the edges of the first portion and the second portion, or the third portion extends from the imaginary extensions along the axial direction of the bearing shell toward the side of the bearing shell by a distance corresponding to the width of the first portion and the second portion at most. This ensures that the third portion does not interfere with the formation of an oil film on the bearing surface.
[0011] According to an embodiment of the present invention, the third portion does not extend beyond the imaginary extension of the edges of the first portion and the second portion in the axial direction of the bearing shell. Therefore, the third portion does not widen the area of the oil groove in the axial direction.
[0012] According to an embodiment of the present invention, the third portion is configured so that on each imaginary line drawn from the first portion to the second portion on the inner surface of the bearing shell in the circumferential direction, there is at least one section located outside the third portion of the oil groove. Therefore, there is no area on the outer surface of the crankpin that does not contact the inner surface of the bearing shell, which helps to keep the wear of the crankpin more uniform.
[0013] According to an embodiment of the present invention, the third portion extends at an angle of 40-100 degrees in the circumferential direction of the bearing shell.
[0014] According to an embodiment of the present invention, the third portion is disposed in the middle of the bearing shell along the circumferential direction.
[0015] According to an embodiment of the present invention, the width of the first portion and the second portion is 15%-30% of the width of the bearing shell.
[0016] According to an embodiment of the present invention, the width of the third portion is 20%-60% of the width of the first portion and the second portion.
[0017] According to an embodiment of the present invention, the oil groove is provided in a middle portion of the bearing shell along an axial direction of the bearing shell.
[0018] According to an embodiment of the present invention, the first portion extends to the first end of the bearing shell in the circumferential direction, and the second portion extends to the second end of the bearing shell. Therefore, the oil groove covers the entire bearing shell in the circumferential direction.
[0019] According to an embodiment of the present invention, both the first portion and the second portion are provided with at least one oil hole.
[0020] According to an embodiment of the invention, the third portion does not comprise any holes.
[0021] According to an embodiment of the invention, the bearing shell has a substantially semicircular shape. Thus, it extends over an angle of approximately 180 degrees.
[0022] According to an embodiment of the present invention, at least a portion of the third portion has a zigzag shape.
[0023] According to an embodiment of the invention, the third portion is straight.
[0024] According to an embodiment of the present invention, at least a portion of the third portion has a serpentine shape.
[0025] A bearing according to the invention for connecting a connecting rod of a piston engine to a crankshaft of the engine comprises a bearing shell as defined above.
[0026] According to an embodiment of the invention, the bearing shell forms the lower half of the bearing, and the upper half of the bearing is formed by a bearing shell comprising no oil groove or a bearing shell comprising an oil groove extending in the circumferential direction only over a portion of the bearing shell.
[0027] The piston engine according to the invention comprises a crankshaft, a connecting rod and a bearing connecting the connecting rod to the crankshaft, the bearing being the bearing defined above.
[0028] The bearing shell defined above may be used as the lower half of a bearing connecting a connecting rod of a piston engine to a crankshaft. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Embodiments of the present invention are described in more detail below with reference to the accompanying drawings, in which
[0030] Figure 1 A portion of a crankshaft and connecting rod of a piston engine and a bearing housing of the prior art are shown,
[0031] Figure 2 Shown with Figure 1 Similar view but at different crank angles,
[0032] Figure 3 shows a prior art bearing shell,
[0033] Figure 4shows a perspective view of a bearing shell according to an embodiment of the invention,
[0034] Figure 5 Shows Figure 1 Plan view of the bearing shell,
[0035] Figure 6 shows a bearing shell according to another embodiment of the present invention, and
[0036] Figure 7 A bearing shell according to a further embodiment of the invention is shown. DETAILED DESCRIPTION
[0037] Figure 1 A portion of a crankshaft 5 and a connecting rod 4 of a piston engine is shown. The engine is a large internal combustion engine, such as a main engine or an auxiliary engine of a ship or an engine used to generate electricity at a power plant. The engine has a cylinder bore of at least 150 mm. Each cylinder of the engine is provided with a piston that moves in a reciprocating manner in the cylinder. The engine may have any reasonable number of cylinders. The connecting rod 4 connects the piston to the crankshaft 5 and converts the reciprocating motion of the piston into a rotational motion of the crankshaft 5.
[0038] The piston moves between top dead center and bottom dead center. Figure 1 In this case, the piston is at top dead center. Figure 2 The piston is shown at bottom dead center.
[0039] The connecting rod 4 is connected to the crankshaft 5 through the bearing 3. The bearing 3 can be called a big end bearing. The bearing 3 is a sliding bearing. The bearing 3 is rotationally fixed to the connecting rod 4. Therefore, the bearing 3 does not rotate relative to the connecting rod 4. The bearing 3 has an inner surface forming a bearing surface. The bearing surface faces the crankpin 6 of the crankshaft 5, and the bearing 3 can rotate relative to the crankpin 6. Lubricating oil is supplied between the crankpin 6 and the bearing surface of the bearing 3 to form an oil film between the components.
[0040] The bearing 3 is formed by two bearing shells 1 and 2. The bearing shells 1 and 2 are semicircular parts. The first lower bearing shell 1 forms the lower half of the bearing 3, and the second upper bearing shell 2 forms the upper half of the bearing 3. The expression "upper half" refers to the half / half of the bearing 3 close to the upper end of the cylinder, i.e. the top dead center. Similarly, the expression "lower half" refers to the half away from the upper end of the cylinder. The longitudinal axis of the cylinder does not need to be aligned with the vertical direction, but for example in a V-type engine, the cylinder can be tilted relative to the vertical direction. Therefore, the bearing 3 is not necessarily divided into two halves by a horizontal plane.
[0041] Figure 1 and Figure 2 The prior art bearing 3 is shown. The lower bearing shell 1 is also Figure 3The lower bearing shell 1 of the bearing 3 is provided with an oil groove 10, which is provided on the inner surface of the bearing shell 1, that is, the bearing surface. The oil groove 10 is straight and extends along the circumferential direction of the bearing shell 1 over the entire bearing shell 1. In the axial direction of the bearing shell 1, the oil groove 10 is provided in the middle of the bearing shell 1. A plurality of oil holes 14 are provided at each end of the oil groove 10.
[0042] exist Figure 1 and Figure 2 In the example of , the upper bearing shell 2 is flat. Therefore, there is no oil groove on the bearing surface of the upper bearing shell 2.
[0043] During the operation of the engine, the crankpin 6 wears. Usually the wear is not uniform, but the lower part of the crankpin 6 wears more. The expression "lower part" refers to the side of the crankpin 6 that is located at the top dead center position of the piston and is far from the top dead center. The lower part of the crankpin 6 is also not worn uniformly. The part aligned with the oil groove 10 wears less than the rest of the surface of the crankpin 6. The wear of the crankpin 6 is caused, for example, by abrasive particles between the bearing surface and the crankpin 6. At the area aligned with the oil groove 10, there is a larger gap between the bearing surface and the crankpin 6, and the abrasive particles therefore do not grind the crankpin 6 to the same extent as other places.
[0044] Due to the uneven wear of the crank pin 6 , a protruding area or ridge 7 gradually forms at the area aligned with the oil groove 10 . Figure 1 and Figure 2 The enlarged view of shows an enlarged view of the ridge 7. The height of the ridge 7 may be similar to the thickness of the oil film on the bearing surface.
[0045] When the crankshaft 5 rotates and the piston approaches the bottom dead center, the ridge 7 comes into contact with the upper bearing shell 2. Because the bearing surface of the upper bearing shell 2 is flat, there is no groove that can accommodate the ridge 7. Therefore, the bearing 3 is loaded more at the area aligned with the ridge 7. Uneven loading of the bearing 3 can cause problems. Problems may be encountered in particular after an engine overhaul. Overloading of the upper bearing shell 2 is even more likely when the bearing 3 has been replaced by a new bearing with an intact bearing surface.
[0046] Problems caused by uneven wear can be reduced by means of the bearing shell 1 according to the invention. The bearing shell 1 according to the invention can be used as a lower bearing shell of a bearing 3 connecting a connecting rod 4 of a piston engine to a crankshaft 5. Thus, the bearing shell 1 according to the invention can replace Figures 1 to 3 The bearing shell 1 is shown. Figures 4 to 7 Some embodiments of the bearing shell 1 according to the invention are shown.
[0047] The inner surface of the bearing shell 1 according to the present invention is provided with an oil groove 10. The oil groove 10 includes a first portion 11, a second portion 12 and a third intermediate portion 13 connecting the first portion 11 and the second portion 13. Therefore, the first portion 11, the second portion 12 and the third portion 13 form a continuous oil groove 10 on the bearing surface. The first portion 11 and the second portion 12 are straight and extend in the circumferential direction of the bearing shell 1. Therefore, the edges of the first portion 11 and the second portion 12 are parallel to the circumferential direction of the bearing shell 1. In the axial direction of the bearing shell 1, the first portion 11 and the second portion 12 are aligned with each other.
[0048] The first portion 11 and the second portion 12 have the same width as each other. In the embodiment of the drawings, the width of the first portion 11 and the second portion 12 is about 20% of the width of the bearing shell 1. The width may be, for example, in the range of 15%-30% of the width of the bearing shell 1. In the embodiment of the drawings, the first portion 11 and the second portion 12 are arranged along the axial direction of the bearing shell 1, i.e., in the middle of the bearing shell 1 along the axial direction of the bearing 3.
[0049] In the bearing shell 1 according to the present invention, the third portion 13 is narrower than the first portion 11 and the second portion 12, and at least a portion of the third portion 13 extends in a direction deviating from the circumferential direction of the bearing shell 1 toward one side of the bearing shell 1. Since the groove is narrower, a larger portion of the bearing shell 1 is in contact with the crank pin 6, and the crank pin 6 wears more evenly. Since the direction of the third portion 13 is different from the circumferential direction, the continuous non-contact portion in the circumferential direction of the bearing shell 1 can be reduced. This reduces the formation of ridges at the area of the oil groove 10.
[0050] The width of the third portion 13 may be, for example, in the range of 20% to 60% of the widths of the first portion 11 and the second portion 12 .
[0051] In the embodiment of the drawings, the third portion 13 is configured so that on each imaginary line drawn in the circumferential direction from the first portion 11 to the second portion 12 on the inner surface of the bearing shell 1, there is at least one section outside the third portion 13. Therefore, each of the imaginary lines includes a portion that is not part of the oil groove 10 but is located on the bearing surface. Therefore, there is no area on the outer surface of the crankpin 6 that is not in contact with the inner surface of the bearing shell 1, which helps to keep the wear of the crankpin 6 more uniform.
[0052] In the embodiment of the figures, the third portion 13 does not extend beyond the edge of the imaginary extension of the first portion 11 and the second portion 12 in the axial direction of the bearing shell 1. Therefore, the entire oil groove 10 is arranged at the area defined by two imaginary planes aligned with the edges of the first portion 11 and the second portion 12. Although it is beneficial that the third portion 13 does not extend beyond the edges of the first portion 11 and the second portion 12, the third portion 13 may extend slightly beyond the edges of the first portion 11 and the second portion 12. Preferably, the third portion 13 extends from the imaginary extension of the edges of the first portion 11 and the second portion 12 in the axial direction of the bearing shell 1 by a distance that at most corresponds to the width of the first portion 11 and the second portion 12 toward the side of the bearing shell 1.
[0053] In the embodiment of the drawings, the first portion 11 extends to the first end of the bearing shell 1 in the circumferential direction, and the second portion 12 extends to the second end of the bearing shell 1. Therefore, the oil groove 10 extends in the circumferential direction over the entire bearing shell 1. However, the oil groove 10 may extend in the circumferential direction of the bearing shell 1 only over a portion of the bearing shell 1. For example, the oil groove 10 may extend at an angle of 100-180 degrees. If the oil groove 10 does not extend over the entire bearing shell 1, the oil groove 10 is preferably arranged in the middle of the bearing shell 1 in the circumferential direction.
[0054] In the embodiment of the drawings, the third portion 13 extends at an angle of about 60 degrees in the circumferential direction of the bearing shell 1. In the bearing shell 1, in which the oil groove 10 extends over the entire bearing shell 1, the third portion 13 may extend at an angle of 40-100 degrees. In the embodiment of the drawings, the third portion 13 is arranged in the middle of the bearing shell 1 in the circumferential direction.
[0055] In the embodiment of the drawings, the first portion 11 and the second portion 12 are each provided with a plurality of oil holes 14. The oil holes 14 extend from the bottom of the oil groove 10 to the outer periphery of the bearing shell 1. The third portion 13 does not include any holes.
[0056] The third portion 13 of the oil groove 10 can have different shapes. Figure 4 and Figure 5In an embodiment of the present invention, the third portion 13 has a sawtooth shape. Therefore, the third portion 13 includes alternating sub-portions 13a, 13b, 13c, 13d arranged at different angles relative to the circumferential direction of the bearing shell 1. The first sub-portion 13a is inclined from the circumferential direction in the axial direction towards the first side of the bearing shell 1, and the subsequent sub-portion 13b is inclined towards the second side of the bearing shell 1. The first sub-portion 13a starts from the first side of the first portion 11 and ends at an imaginary extension of the second side of the first portion 11. The width and angle of the first sub-portion 13a are configured so that the starting point of the first sub-portion 13a is located on a first side of the imaginary extension of the center line of the first portion 11, and the end point of the first sub-portion 13a is located on a second side of the extension.
[0057] exist Figure 6 In the embodiment of the present invention, the third portion 13 is straight. The third portion 13 is connected to the first portion 11 on a first side of the first portion 11 and to the second portion 12 on an opposite side of the second portion 12. The width and angle of the third portion 13 are configured so that both ends of the third portion 13 are completely located on opposite sides of the center line of the first portion 11 and the second portion 12.
[0058] exist Figure 7 In the embodiment of the present invention, the third portion 13 has a meandering shape. Therefore, the shape is similar to Figure 5 The third portion 13 has a zigzag shape, but instead of a straight subsection, the third portion 13 includes a curved subsection. Even in this embodiment, at least a portion of the third portion 13 is arranged not to overlap with an imaginary extension of the center line of the first portion 11 and the second portion 12.
[0059] Many other shapes of the third portion 13 are also possible. For example, the third portion 13 may comprise two straight sub-portions forming a V-shaped groove, or the third portion 13 may have a U-shape. Different shapes may also be combined.
[0060] There may be a transition zone between the first portion 11 and the third portion 13 , in which the width of the oil groove 10 gradually decreases. A similar transition zone may be arranged between the third portion 13 and the second portion 12 .
[0061] In a bearing using the bearing shell 1 according to the present invention as the lower bearing shell 1, the upper bearing shell 2 may be similar to the bearing shell 2 of the prior art. For example, the upper bearing shell 2 may have a bearing surface without any oil groove. Alternatively, the upper bearing shell 2 may be provided with an oil groove extending in the circumferential direction only on a portion of the bearing shell 2. For example, the upper bearing shell 2 may be provided with oil grooves at both ends thereof, which are configured to form a continuation of the first portion 11 and the second portion 12 of the oil groove 10 of the lower bearing shell 1.
[0062] It will be appreciated by a person skilled in the art that the invention is not limited to the embodiments described above, but may be varied within the scope of the appended claims.
Claims
1. A bearing shell (1) for a bearing (3) connecting a connecting rod (4) of a piston engine to a crankshaft (5), wherein the inner surface of the bearing shell (1) is provided with an oil groove (10), the oil groove (10) comprising a first portion (11), a second portion (12) and a third intermediate portion (13) connecting the first portion (11) and the second portion (12), wherein: The first portion (11) and the second portion (12) are straight and extend along the circumference of the bearing shell (1), and wherein the third portion (13) is narrower than the first portion (11) and the second portion (12), and at least a portion of the third portion (13) extends in a direction deviating from the circumferential direction of the bearing shell (1) toward one side of the bearing shell (1) along the axial direction of the bearing shell (1).
2. The bearing shell (1) according to claim 1, wherein: The third portion (13) is arranged between imaginary extensions of the edges of the first portion (11) and the second portion (12), or wherein, The third portion (13) extends from the imaginary extension toward the side of the bearing shell (1) in the axial direction of the bearing shell (1) by a distance that corresponds at most to the width of the first portion (11) and the second portion (12).
3. The bearing shell (1) according to claim 1 or 2, wherein: The third portion (13) does not extend in the axial direction of the bearing shell (1) beyond the imaginary extension of the edges of the first portion (11) and the second portion (12).
4. The bearing shell (1) according to any one of claims 1 to 3, wherein: The third portion (13) is configured so that on each imaginary line drawn along the circumferential direction from the first portion (11) on the inner surface of the bearing shell (1) to the second portion (12), there is at least one section located outside the third portion (13) of the oil groove (10).
5. The bearing shell (1) according to any one of the preceding claims, wherein: The third portion (13) extends along the circumferential direction of the bearing shell (1) through an angle of 40-100 degrees.
6. The bearing shell (1) according to any one of the preceding claims, wherein: The third portion (13) is arranged in the middle of the bearing shell (1) along the circumferential direction.
7. The bearing shell (1) according to any one of the preceding claims, wherein: The width of the first portion (11) and the second portion (12) is 15%-30% of the width of the bearing shell (1).
8. The bearing shell (1) according to any one of the preceding claims, wherein: The width of the third portion (13) is 20%-60% of the width of the first portion (11) and the second portion (12).
9. The bearing shell (1) according to any one of the preceding claims, wherein: The oil groove (10) is arranged in the middle of the bearing shell (1) along the axial direction of the bearing shell (1).
10. The bearing shell (1) according to any one of the preceding claims, wherein: The first portion (11) extends along the circumferential direction to a first end of the bearing shell (1), and the second portion (12) extends to a second end of the bearing shell (1).
11. The bearing shell (1) according to any one of the preceding claims, wherein: The first part (11) and the second part (12) are each provided with at least one oil hole (14).
12. The bearing shell (1) according to any one of the preceding claims, wherein: The third portion (13) does not comprise any holes.
13. The bearing shell (1) according to any one of the preceding claims, wherein: The bearing shell (1) has a substantially semicircular shape.
14. The bearing shell (1) according to any one of the preceding claims, wherein: At least a portion of the third portion (13) has a sawtooth shape.
15. The bearing shell (1) according to any one of claims 1 to 13, wherein: The third portion (13) is straight.
16. The bearing shell (1) according to any one of claims 1 to 14, wherein: At least a portion of the third portion (13) has a serpentine shape.
17. A bearing (3) for connecting a connecting rod (4) of a piston engine to a crankshaft (5) of the engine, wherein: The bearing (3) comprises a bearing shell (1) according to any one of the preceding claims.
18. The bearing (3) according to claim 17, wherein: The bearing shell (1) forms the lower half of the bearing (3), and the upper half of the bearing (3) is formed by a bearing shell (2), and the bearing shell (2) forming the upper half does not include an oil groove or only includes an oil groove extending along the circumferential direction on a part of the bearing shell (2).
19. A piston engine comprising a crankshaft (5), a connecting rod (4) and a bearing (3) connecting the connecting rod (4) to the crankshaft (5), wherein: The bearing (3) is a bearing (3) according to claim 17 or 18.
20. Use of a bearing shell (1) according to any one of claims 1 to 16 as the lower half of a bearing (3) connecting a connecting rod (4) of a piston engine to a crankshaft (5).