Bearing element, camshaft bearing and piston engine

Abstract

The bearing element (1) for a camshaft bearing of a piston engine includes: an oil supply hole (2) disposed in the upper half of the bearing element (1); an oil supply groove (3A, 3B) disposed on the bearing surface and extending from the oil supply hole (2) toward the lower half of the bearing element (1); and an oil distribution groove (5) disposed in the lower half of the bearing element (1) and in fluid communication with the oil supply groove (3A, 3B), the width of the oil distribution groove (5) being at most 30% of the width of the oil supply groove (5).

Description

Technical Field

[0001] This invention relates to a bearing element for a camshaft bearing in a piston engine as defined in claim 1. The invention also relates to a camshaft bearing for a piston engine and a piston engine. Background Technology

[0002] In large piston engines such as those used in ships and power plants, camshafts are typically supported by sliding bearings. A typical camshaft bearing consists of a bearing housing with an inner circumferential surface forming the bearing surface. Lubricating oil is introduced onto the bearing surface to form an oil film between the bearing surface and the camshaft. The lubricating oil is typically supplied from the engine block and introduced onto the bearing surface via an oil supply hole extending from the outer surface of the bearing housing to the inner surface.

[0003] Different types of camshaft bearings are known. In the simplest form of a camshaft bearing, the bearing surface is flat. Some camshaft bearings include grooves that extend partially from the oil supply hole on the bearing surface. Similarly, bearings with grooves extending circumferentially across the entire bearing surface are known, but they are generally not used in high-load bearings next to the cams of camshafts.

[0004] When the valve tappet rollers are spring-biased against the camshaft cams, the camshaft bearings experience relatively high loads even at low camshaft rotation speeds. The maximum load on the bearings is at the lower end. Lubrication of the camshaft bearings is most ineffective at low camshaft speeds. As a result, the camshaft bearings may suffer from insufficient lubrication during slow engine starts and rotation. In some applications, starts and slow rotation may occur periodically, which can lead to significant wear of the camshaft bearings if adequate lubrication is not ensured. Summary of the Invention

[0005] The object of this invention is to provide an improved bearing element for a camshaft bearing in a piston engine. Another object of this invention is to provide an improved camshaft bearing and an improved piston engine.

[0006] The bearing element according to the present invention has an outer circumferential surface and an inner circumferential surface configured to form a bearing surface. The bearing element is used in the following locations: - At least one oil supply hole, said at least one oil supply hole being arranged in the upper half of the bearing element and extending from the outer circumferential surface of the bearing element to the inner circumferential surface; - At least one oil supply groove, said at least one oil supply groove being disposed on the bearing surface and extending from said at least one oil supply hole toward the lower half of the bearing element; and - An oil distribution groove, which is arranged in the lower half of the bearing element and is in fluid communication with the at least one oil supply groove, wherein the longitudinal direction of the oil distribution groove is different from the axial direction of the bearing element, and the width of the oil distribution groove is at most 30% of the width of the oil supply groove.

[0007] The camshaft bearing according to the present invention includes the bearing elements defined above.

[0008] The piston engine according to the present invention includes the camshaft bearing defined above.

[0009] In the bearing element according to the invention, the lubricating oil is supplied to the bearing surface through one or more oil supply holes arranged in the upper part of the bearing. The maximum load portion of the bearing is the lower part. When the camshaft rotates at a high speed, the rotational motion of the camshaft effectively delivers the lubricating oil to the lower part of the bearing element. However, during engine startup and during slow rotation of the camshaft, lubrication of the lower part of the bearing is less effective. The oil supply groove also ensures that a sufficient amount of lubricating oil is delivered to the lower half of the bearing during slow rotation of the camshaft. The oil distribution groove in the lower half of the bearing element helps the lubricating oil to spread below the camshaft. Because the oil distribution groove is narrower than the oil supply groove, a sufficient oil film thickness can be maintained even during higher camshaft speeds. The oil distribution groove also helps to remove dirt particles from the bearing and can reduce problems caused by thermal expansion of the bearing element.

[0010] According to an embodiment of the present invention, the bearing element includes a first oil supply groove and a second oil supply groove. The first oil supply groove extends from one of the at least one oil supply hole in a first circumferential direction, and the second oil supply groove extends from one of the at least one oil supply hole in a second circumferential direction. Each of the oil supply grooves is in fluid communication with the oil distribution groove. By providing the bearing element with two oil supply grooves, the same bearing element can be used for bearings of camshafts with different rotation directions. Furthermore, the second oil supply groove can be used as a discharge groove to remove excess lubricating oil from the bearing.

[0011] According to an embodiment of the invention, the bearing element includes at least one oil cavity formed by a recessed region disposed on the bearing surface between one of the oil distribution groove and the at least one oil supply groove, and extending in the axial direction of the bearing element to at least 50% of the width of the bearing element. The oil cavity serves as a reservoir for supplying lubricating oil to the maximum load portion of the bearing. The oil cavity also facilitates the distribution of lubricating oil across the entire width of the bearing surface.

[0012] According to an embodiment of the present invention, the bearing element includes a first oil chamber and a second oil chamber, the first oil chamber being disposed between the first oil supply groove and the oil distribution groove, and the second oil chamber being disposed between the second oil supply groove and the oil distribution groove. In the case of a bearing element having two oil supply grooves, the oil chambers can be disposed at the lower end of each of the oil supply grooves.

[0013] According to an embodiment of the invention, each of the at least one oil cavity extends in the axial direction of the bearing element to at least 70% of the width of the bearing element. The greater width of the oil cavity improves the distribution of the lubricating oil on the bearing surface.

[0014] According to an embodiment of the present invention, each of the at least one oil cavity extends at an angle of 10 to 30 degrees in the circumferential direction of the bearing element.

[0015] According to an embodiment of the invention, the width of the oil distribution groove is less than 20% or less than 15% of the width of the oil supply groove. A narrower oil distribution groove is advantageous when the camshaft rotates at a higher speed.

[0016] According to an embodiment of the invention, the width of each of the at least one oil supply groove is 15% to 30% of the width of the bearing element. This ensures that sufficient oil is supplied to the lower part of the bearing element.

[0017] According to an embodiment of the present invention, the oil distribution groove extends 60 to 120 degrees, or 80 to 100 degrees, in the circumferential direction of the bearing element. Therefore, the oil distribution groove extends over the maximum load area of ​​the bearing element.

[0018] According to an embodiment of the invention, each of the at least one oil supply hole is located in a region extending at an angular distance of 45 degrees from the highest point of the bearing element. Therefore, the oil supply hole is located in the uppermost quarter of the bearing element.

[0019] According to an embodiment of the invention, the oil distribution groove extends in a direction different from the circumferential direction of the bearing element. This longitudinal direction, different from the circumferential direction of the bearing element, facilitates maintaining a sufficient lubricating oil film thickness across the entire width of the bearing element.

[0020] According to an embodiment of the invention, the depth of the oil distribution groove is less than 1.0 mm. A sufficiently shallow oil distribution groove helps to ensure that a sufficient lubricating oil film thickness is maintained even when the camshaft rotates at high speeds. Attached Figure Description

[0021] The embodiments of the present invention will now be described in more detail with reference to the accompanying drawings, wherein... Figure 1 A bearing element according to an embodiment of the present invention is shown, and Figure 2 It shows Figure 1 A cross-sectional view of the bearing component. Detailed Implementation

[0022] Figure 1 A bearing element 1 according to an embodiment of the present invention is shown. Bearing element 1 can be used in the camshaft bearing of a large piston engine. Here, "large piston engine" refers to an engine having a cylinder diameter of at least 150 mm. This engine can be, for example, a main engine or auxiliary engine of a ship or a power plant engine. Bearing element 1 is configured to form part of a sliding bearing. This bearing is a camshaft bearing, configured to abut against the engine block and support the engine's camshaft.

[0023] Bearing element 1 is a bushing and therefore extends over the entire circle. Bearing element 1 has an inner circumferential surface and an outer circumferential surface. The inner circumferential surface is configured to serve as a bearing surface. Therefore, the inner circumferential surface is configured to support a camshaft that can rotate relative to bearing element 1.

[0024] The bearing element 1 includes an oil supply hole 2 extending from its outer circumferential surface to its inner surface. Lubricating oil can be supplied to the inner surface of the bearing element 1 via the oil supply hole 2. The lubricating oil can be supplied to the bearing element 1 via a channel formed in the engine cylinder and to the bearing surface via the oil supply hole 2. Therefore, an oil film is formed between the bearing surface and the camshaft that rotates against the bearing element 1, thereby preventing direct contact between the surface of the bearing element 1 and the camshaft.

[0025] In the embodiment shown in the accompanying drawings, the bearing element 1 includes a single oil supply hole 2. This oil supply hole 2 is arranged in the upper half of the bearing element 1. Here, the term "upper half" refers to the portion located above an imaginary horizontal plane that divides the bearing element 1 into two equal-sized halves when in use. The lower half of the bearing element 1 is the portion located below the imaginary plane. Furthermore, other expressions used in this application that refer to direction refer to the orientation of the bearing element 1 in its use position.

[0026] In the embodiment shown in the accompanying drawings, the central axis of the oil supply hole 2 is positioned at an angular distance of 10 degrees from the highest point of the bearing element 1. However, the central axis of the oil supply hole 2 can also be aligned with the highest point of the bearing element 1. Preferably, the oil supply hole 2 is located within a region extending from the highest point of the bearing element 1 to an angular distance of 45 degrees.

[0027] The bearing element 1 also includes oil supply grooves 3A and 3B arranged on the bearing surface and extending from the oil supply hole 2 toward the lower half of the bearing element 1.

[0028] In the embodiment shown in the accompanying drawings, the bearing element 1 includes a first oil supply groove 3A and a second oil supply groove 3B. The first oil supply groove 3A extends from the oil supply hole 2 in a first circumferential direction. Figure 1 The direction is counterclockwise. The second oil supply groove 3B extends from the oil supply hole 2 in the second circumferential direction, which is in... Figure 1 The direction is clockwise. Oil supply grooves 3A and 3B are configured to deliver lubricating oil from the oil supply hole 2 to the lower part of the bearing element 1. The width of the oil supply grooves 3A and 3B can be 15% to 30% of the width of the bearing element 1. Viewed axially from the bearing element 1, the depth of the oil supply grooves 3A and 3B can, for example, be in the range of 1.0 mm to 4.0 mm at the midpoint of the oil supply grooves 3A and 3B. In the embodiment shown in the figures, the first oil supply groove 3A and the second oil supply groove 3B are otherwise identical, but the second oil supply groove 3B is longer because the oil supply hole 2 is not arranged at the highest point of the bearing element 1. The first oil supply groove 3A and the second oil supply groove 3B are aligned with the mid-plane of the bearing element 1.

[0029] The bearing element 1 also includes an oil distribution groove 5, which is arranged in the lower half of the bearing element 1 and is in fluid communication with the oil supply grooves 3A and 3B. The longitudinal direction of the oil distribution groove 5 is different from the axial direction of the bearing element 1. Therefore, the oil distribution groove 5 is configured to deliver lubricating oil along the circumferential direction of the bearing element 1. In the embodiment shown in the figures, the oil distribution groove 5 is not parallel to the circumferential direction of the bearing element 1, but extends in a direction different from the circumferential direction of the bearing element 1. However, the oil distribution groove 5 can also be parallel to the circumferential direction of the bearing element 1. For example, the oil distribution groove 5 can be aligned with the mid-plane of the bearing element 1.

[0030] The width of the oil distribution trough 5 is at most 30% of the width of the oil supply troughs 3A and 3B. The oil distribution trough 5 can be narrower, for example, less than 20% or 15% of the width of the oil supply troughs 3A and 3B. The oil distribution trough 5 can be shallower than the oil supply troughs 3A and 3B. The depth of the oil distribution trough 5 can be configured to be less than 1.0 mm. The oil distribution trough 5 can be configured to have even smaller depths, for example, less than 0.5 mm.

[0031] In the embodiment shown in the accompanying drawings, the bearing element 1 includes a first oil cavity 4A and a second oil cavity 4B. Each oil cavity 4A, 4B is formed by a recessed region disposed on the bearing surface between the oil distribution groove 5 and one of the oil supply grooves 3A, 3B. The first oil cavity 4A is located between the first oil supply groove 3A and the oil distribution groove 5, while the second oil cavity 4B is located between the second oil supply groove 3B and the oil distribution groove 5. Each oil cavity 4A, 4B extends along the axial direction of the bearing element 1 to at least 50% of the width of the bearing element 1, preferably to at least 70% of the width of the bearing element 1. In the circumferential direction of the bearing element 1, each oil cavity 4A, 4B can be formed to extend at an angle of 10 to 30 degrees. One end of the oil distribution groove 5 is connected to the first oil cavity 4A, and the other end of the oil distribution groove 5 is connected to the second oil cavity 4B. The first oil supply groove 3A extends from the oil supply hole 2 to the first oil cavity 4A, while the second oil supply groove 3B extends from the oil supply hole 2 to the second oil cavity 4B.

[0032] In the embodiment shown in the accompanying drawings, the oil distribution groove 5 is connected to the first oil cavity 4A at a position from the mid-plane of the bearing element 1 toward the first edge of the bearing element 1, and to the second oil cavity 4B at a position from the mid-plane of the bearing element 1 toward the second edge of the bearing element 1. Therefore, the longitudinal direction of the oil distribution groove 5 deviates from the circumferential direction of the bearing element 1.

[0033] Each of the first oil chamber 4A and the second oil chamber 4B can be positioned such that the central axis of the oil chambers 4A and 4B is located at an angular distance of 40 to 70 degrees from the lowest point of the bearing element 1. Preferably, the central axis of the oil chambers 4A and 4B is located at an angular distance of 45 to 65 degrees from the lowest point of the bearing element 1. In the embodiment shown in the drawings, the first oil chamber 4A and the second oil chamber 4B are arranged symmetrically about a plane parallel to the axial direction of the bearing element 1 and in a vertical position where the bearing element 1 is in use.

[0034] The oil distribution groove 5 can extend 60 to 120 degrees along the circumferential direction of the bearing element 1. Preferably, the oil distribution groove 5 extends 80 to 100 degrees along the circumferential direction of the bearing element 1. In the embodiment shown in the figures, the oil distribution groove 5 is arranged to extend the same angular distance from the lowest point of the bearing element 1 along each circumferential direction.

[0035] Oil supply grooves 3A and 3B, extending from the oil supply hole 2 along the rotational direction of the camshaft toward the lower half of the bearing element 1, ensure a sufficient amount of lubricating oil is supplied to the maximum load portion of the bearing. While the oil supply grooves 3A and 3B reduce the thickness of the oil film, because they are located in the less load portion of the bearing, the oil film thickness can be maintained at a sufficient level.

[0036] Oil chambers 4A and 4B, which receive lubricating oil from oil supply tanks 3A and 3B, serve as oil reservoirs from which lubricating oil is supplied to the maximum load portion of the bearing. Oil chambers 4A and 4B also distribute lubricating oil across the entire width of the bearing surface. However, in some applications, bearing elements 1 without oil chambers 4A and 4B may also be used.

[0037] When the camshaft speed is low, the oil distribution groove 5 improves the function of the bearing 1. It provides lubrication to the bearing's maximum load area and helps prevent oil shortage. When the camshaft speed is high, the oil distribution groove 5 reduces the oil film thickness. However, since the cross-sectional area of ​​the oil distribution groove 5 is much smaller than that of the oil supply grooves 3A and 3B, the effect is minimized. Therefore, the bearing element 1 according to the invention provides reliable operation at both low and high camshaft speeds.

[0038] The bearing element 1 may include two or more oil supply holes 2. In the case of two oil supply holes 2, a first oil supply groove 3A may be connected to the first oil supply hole, and a second oil supply groove 3B may be connected to the second oil supply hole. Although the accompanying drawings show an embodiment including two oil supply grooves 3A and 3B, the bearing element 1 may also be provided with a single oil supply groove. In this case, there may be a single oil cavity between the lower end of the oil distribution groove and the oil supply groove. The oil supply groove and the oil distribution groove may be positioned such that the oil supply groove is located ahead of the oil distribution groove in the rotational direction of the camshaft 10.

Claims

1. A bearing element (1) for a camshaft bearing of a piston engine, said bearing element (1) having an outer circumferential surface and an inner circumferential surface configured to form a bearing surface, said bearing element (1) comprising, in a usage position: - At least one oil supply hole (2), said at least one oil supply hole is arranged in the upper half of the bearing element (1) and extends from the outer circumferential surface of the bearing element (1) to the inner circumferential surface. - At least one oil supply groove (3A, 3B), said at least one oil supply groove being arranged on the bearing surface and extending from said at least one oil supply hole (2) toward the lower half of the bearing element (1), and - An oil distribution groove (5) is arranged in the lower half of the bearing element (1) and is in fluid communication with the at least one oil supply groove (3A, 3B). The longitudinal direction of the oil distribution groove (5) is different from the axial direction of the bearing element (1), and the width of the oil distribution groove (5) is at most 30% of the width of the oil supply groove (3A, 3B).

2. The bearing element (1) according to claim 1, wherein, The bearing element (1) includes a first oil supply groove (3A) and a second oil supply groove (3B). The first oil supply groove extends from one of the at least one oil supply hole (2) in a first circumferential direction, and the second oil supply groove extends from one of the at least one oil supply hole (2) in a second circumferential direction. Each of the oil supply grooves (3A, 3B) is in fluid communication with the oil distribution groove (5).

3. The bearing element (1) according to claim 1 or 2, wherein, The bearing element (1) includes at least one oil cavity (4A, 4B) formed by a recessed region arranged on the bearing surface between one of the oil distribution groove (5) and the at least one oil supply groove (3A, 3B), and extending in the axial direction of the bearing element (1) to at least 50% of the width of the bearing element (1).

4. The bearing element (1) according to claims 2 and 3, wherein, The bearing element (1) includes a first oil chamber (4A) and a second oil chamber (4B). The first oil chamber is arranged between the first oil supply groove (3A) and the oil distribution groove (5), and the second oil chamber is arranged between the second oil supply groove (3B) and the oil distribution groove (5).

5. The bearing element (1) according to claim 3 or 4, wherein, Each of the at least one oil cavity (4A, 4B) extends in the axial direction of the bearing element (1) to at least 70% of the width of the bearing element (1).

6. The bearing element (1) according to any one of claims 3 to 5, wherein, Each of the at least one oil cavity (4A, 4B) extends at an angle of 10 to 30 degrees in the circumferential direction of the bearing element (1).

7. The bearing element (1) according to any one of the preceding claims, wherein, The width of the oil distribution trough (5) is less than 20% of the width of the oil supply troughs (3A, 3B).

8. The bearing element (1) according to claim 7, wherein, The width of the oil distribution trough (5) is less than 15% of the width of the oil supply troughs (3A, 3B).

9. The bearing element (1) according to any one of the preceding claims, wherein, The width of each of the at least one oil supply groove (3A, 3B) is 15% to 30% of the width of the bearing element (1).

10. The bearing element (1) according to any one of the preceding claims, wherein, The oil groove (5) extends 60 to 120 degrees in the circumferential direction of the bearing element (1).

11. The bearing element (1) according to claim 10, wherein, The oil groove (5) extends 80 to 100 degrees in the circumferential direction of the bearing element (1).

12. The bearing element (1) according to any one of the preceding claims, wherein, Each of the at least one oil supply hole (2) is located in a region extending from the highest point of the bearing element (1) at an angular distance of 45 degrees.

13. The bearing element (1) according to any one of the preceding claims, wherein, The oil groove (5) extends in a direction different from the circumferential direction of the bearing element (1).

14. The bearing element (1) according to any one of the preceding claims, wherein, The depth of the oil trough (5) is less than 1.0 mm.

15. A camshaft bearing for a piston engine, wherein, The bearing includes a bearing element (1) according to any one of the preceding claims.

16. A piston engine comprising a camshaft bearing according to claim 15.

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