Ship stern tube bearing capable of improving boundary lubrication effect

Abstract

The invention provides a ship stern tube bearing capable of improving boundary lubrication effect, which is characterized in that the ship stern tube bearing comprises a bearing main body, the bearing main body comprises a bearing front end face, a bearing rear end face and a shaft hole penetrating through the bearing front end face and the bearing rear end face, and the inner surface of the bearing main body sequentially comprises a front end micro-cone section, a cylindrical hole section, a conical hole section and a rear end micro-cone section, and the inner diameter of the conical hole section is increased from the front end surface of the bearing to the rear end of the bearing. After the propeller shaft is assembled with the inner hole of the bearing, the gap between the shaft and the bearing at the position of the conical hole section is not a fixed value but a gradual change value. Due to the fact that the gap between the shaft and the bearing is the gradually-changing value, when the gap is filled with lubricating oil, the thickness of an oil film is in a gradually-changing state. When a propeller shaft rotates, a mixed lubrication state can be generated on the boundary of the bearing, effective boundary lubrication is formed, an oil film on the boundary is prevented from losing efficacy, and high temperature of the bearing caused by dry friction is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of shipbuilding, in particular to a ship stern tube bearing with improved boundary lubrication effect. Background Art

[0002] The stern tube bearing of a ship is the core component of the shaft system. It supports the propeller and stern shaft to ensure that the shaft system can work normally under various working conditions. The stern tube bearing ensures the rotation accuracy of the shaft system by reducing the friction coefficient during movement.

[0003] Existing stern tube bearings are prone to high temperature problems when in use, especially under some harsh working conditions during the ship's navigation (such as when turning a large rudder angle). The lubrication state of the stern bearing directly affects its service life and the operating stability of the shaft system. Good lubrication can reduce friction and wear, extend the service life of the bearing, and protect the journal from damage. The performance of the stern bearing directly affects the propulsion efficiency and navigation stability of the ship. If the stern bearing fails or is severely worn, it will cause problems such as poor operation of the shaft system, increased vibration, and increased noise, which will in turn affect the navigation performance and safety of the ship. If the stern tube bearing fails due to high temperature, it is very expensive to go into the dock to replace the bearing. Summary of the invention

[0004] According to the analysis of the inventors, the reason why the above-mentioned stern tube bearings are damaged by high temperature is that the boundary lubrication effect of the stern tube bearings is poor. Under some harsh working conditions, the lubrication conditions of the stern tube bearings may become harsh, resulting in poor boundary lubrication. Boundary lubrication refers to the formation of an extremely thin lubricating film between the friction surfaces by the lubricant to reduce friction and wear. If this lubricating film is destroyed or cannot be formed, it will lead to increased friction and high temperature. Another reason lies in the design or manufacturing of the bearings. Improper material selection, unreasonable structural design, insufficient processing accuracy, etc. of the bearings may affect the lubrication effect and heat dissipation performance of the bearings. There are three main types of existing stern tube rear bearings: 1) the inner hole of the bearing has no slope, 2) the inner hole of the bearing has a single slope, and 3) the inner hole of the bearing has a double slope. The above three types of bearings are all calculated based on the overall effective contact of the bearing contact surface, without considering local boundary lubrication.

[0005] In order to solve the above technical problems, the present invention provides a ship stern tube bearing with improved boundary lubrication effect. By improving the design of the ship stern tube bearing, when the propeller shaft rotates, a mixed lubrication state will be generated at the bearing boundary, forming effective boundary lubrication, preventing the oil film on the boundary from failing, and avoiding high temperature of the bearing caused by dry friction.

[0006] Mixed lubrication refers to a lubrication state in which the normal load is shared by the fluid lubrication film, boundary lubrication film, ordered molecular film and rough peak-to-dry contact, while the friction force includes fluid damping, shear between lubricating molecules and solid shear friction components. This combination enables the bearing to obtain good lubrication effect under different working conditions, thereby reducing friction and wear.

[0007] The present invention provides a ship stern tube bearing with improved boundary lubrication effect, characterized in that it comprises a bearing body, the bearing body comprises a bearing front end face, a bearing rear end face and an axial hole penetrating the bearing front end face and the bearing rear end face, the inner surface of the bearing body comprises a front end micro-cone section, a cylindrical hole section, a conical hole section and a rear end micro-cone section in sequence, wherein the inner diameter of the conical hole section changes from small to large along the direction from the bearing front end face to the bearing rear end.

[0008] Furthermore, the sum of the lengths of the cylindrical hole section and the conical hole section is L, and the inner diameter of the cylindrical hole section is D, wherein L≥2D.

[0009] Further, the taper value of the front micro-cone section is 1:Y, and the taper value of the conical hole section is 1:X, wherein 1:Y>1:X;

[0010] Further, the taper value of the rear micro-cone section is 1:Z, and the taper value of the conical hole section is 1:X, wherein 1:Z>1:X;

[0011] Furthermore, the taper value of the front micro-cone section is 1:Y, the taper value of the rear micro-cone section is 1:Z, and the taper value of the conical hole section is 1:X, wherein 1:Y>1:X and 1:Z>1:X.

[0012] Furthermore, the outer surface of the bearing body includes a first guide groove, and the first guide groove extends from the front end surface of the bearing to the rear end surface of the bearing.

[0013] Furthermore, the outer surface of the bearing body includes a second guide groove, and the second guide groove extends from the front end surface of the bearing to the rear end surface of the bearing.

[0014] Furthermore, the inner surface of the bearing body includes a third guide groove, and the third guide groove extends from the front end surface of the bearing to the rear end surface of the bearing.

[0015] Furthermore, the second guide groove includes a guide hole, and the guide hole penetrates from the second guide groove to the inner surface of the bearing body.

[0016] Furthermore, the second guide groove and the third guide groove correspond to each other in the axial position of the bearing body, and the second guide groove includes a guide hole, which penetrates from the second guide groove to the third guide groove.

[0017] The ship stern tube bearing with improved boundary lubrication effect provided by the present invention, when the propeller shaft and the inner hole of the bearing are assembled, the gap between the shaft and the bearing at the position of the tapered hole section is not a constant value, but a gradual value. Because the gap between the shaft and the bearing is a gradual value, when the gap is filled with lubricating oil, the thickness of the oil film is also in a gradual state. When the propeller shaft rotates, a mixed lubrication state will be generated at the bearing boundary, forming effective boundary lubrication, preventing the oil film on the boundary from failing, and avoiding high bearing temperature caused by dry friction. It can solve the problem that the stern tube bearings of existing ships with long shaft systems and complex stern flow fields are prone to high temperatures. At the same time, it can solve the problem that the stern tube bearings of ships are prone to high temperatures under harsh working conditions such as large rudder angles. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 An axonometric view showing a ship stern tube bearing with improved boundary lubrication effect according to an embodiment of the present invention;

[0019] Figure 2 A cross-sectional view along the central axis of a ship stern tube bearing with improved boundary lubrication effect according to an embodiment of the present invention;

[0020] Figure 3 A schematic diagram showing an inner hole profile of a ship stern tube bearing for improving boundary lubrication effect according to an embodiment of the present invention;

[0021] In the figure, 1-bearing body, 2-shaft, 10-first guide groove, 20-second guide groove, 30-third guide groove, 40-guide hole, 100-front end micro-cone section, 200-cylindrical hole section, 300-conical hole section, 400-rear end micro-cone section. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In the description of this application, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0025] like Figure 1-2 As shown, Figure 1 An axonometric view showing a ship stern tube bearing with improved boundary lubrication effect according to an embodiment of the present invention, Figure 2 A cross-sectional view of a ship stern tube bearing with improved boundary lubrication effect along the central axis according to an embodiment of the present invention is shown. The right side of the figure represents the front end of the bearing, that is, the bow direction of the ship, and the left side represents the rear end of the bearing, that is, the stern direction of the ship, that is, the stern direction of the ship.

[0026] Specifically, the bearing body 1 includes a bearing front end face, a bearing rear end face and an axial hole passing through the bearing front end face and the bearing rear end face, and the inner surface of the bearing body includes a front end micro-cone section 100, a cylindrical hole section 200, a conical hole section 300 and a rear end micro-cone section 400 in sequence, wherein the inner diameter of the conical hole section changes from small to large along the direction from the bearing front end face to the bearing rear end.

[0027] Among them, the bearing body can be a white alloy stern tube bearing, which is made of bronze and white alloy, has good wear resistance, does not damage the shaft neck, has high compressive strength, and dissipates heat quickly, and is not prone to shaft burning accidents due to frictional heat.

[0028] The stern bearing reduces the friction coefficient during the movement of the shaft system and ensures its rotation accuracy. When the tail shaft is running, the tail shaft and the tail bearing produce relative movement and form a wedge-shaped space. The lubricating oil therein is squeezed by a regular force in the wedge-shaped space, generating a certain reaction force, and due to the viscosity of the lubricating oil itself, a layer of oil film is formed between the tail shaft and the tail bearing, filling the narrow wedge-shaped space between the tail shaft and the bearing. When the working conditions are severe, the wedge-shaped space will be reduced, and the lubrication conditions of the stern tube bearing may become severe, resulting in poor boundary lubrication effect. The present invention designs the rear end section of the stern bearing to have a conical tapered hole section, and the inner diameter of the tapered hole section gradually increases from the shaft hole to the rear end of the shaft, so that the gap between the shaft and the bearing is not a fixed value, but a gradual value. Therefore, when the gap is filled with lubricating oil, the thickness of the oil film is also a gradual state. When the propeller shaft rotates, a mixed lubrication state will be generated at the bearing boundary to form effective boundary lubrication.

[0029] In another embodiment of the present invention, the outer surface of the bearing body 1 includes a first guide groove 10, and the first guide groove extends from the front end surface of the bearing to the rear end surface of the bearing. The first guide groove can be a groove opened along the axial direction of the bearing body. One or more first guide grooves can be arranged at intervals along the axial direction of the bearing body. Preferably, the first guide grooves are evenly spaced along the axial direction of the bearing body.

[0030] The first guide groove can be used as a positioning and locking device for the bearing to ensure that the bearing remains in the same position during installation. Since the ship is affected by various external forces and vibrations during navigation, if the bearing moves or shifts during use, it may cause damage to the bearing or increased wear. Therefore, the existence of the first guide groove can ensure the stability and reliability of the bearing and prevent it from moving during use.

[0031] In addition, during the operation of the ship's stern tube bearing, a large amount of heat is generated due to friction and vibration. The presence of the first guide groove can increase the contact area between the bearing and the surrounding environment, which is conducive to the dissipation of heat and the reduction of the temperature of the bearing. This helps to maintain the normal operating temperature of the bearing and prevent damage or failure due to overheating. At the same time, coolant can be introduced into the first guide groove, which helps to maintain the normal operating temperature of the bearing and prevent damage or failure due to overheating.

[0032] Among them, evenly arranging the first guide grooves can ensure the uniformity of the bearing support force and the adequacy of cooling.

[0033] In another embodiment of the present invention, the outer surface of the bearing body 1 includes a second guide groove 20, and the second guide groove 20 extends from the front end surface of the bearing to the rear end surface of the bearing. The second guide groove can be a groove opened along the axial direction of the bearing body. One or more second guide grooves can be arranged at intervals along the axial direction of the bearing body. Preferably, the second guide groove is opened in the upper half of the bearing body. In another preferred embodiment, the second guide grooves are arranged symmetrically along the vertical cross section of the bearing body.

[0034] In a further embodiment, a guide hole 40 is opened in the second guide groove, and the guide hole 40 penetrates from the second guide groove to the inner surface of the bearing body, that is, the guide hole connects the inner and outer surfaces of the bearing body.

[0035] During the operation of the ship's stern tube bearing, the friction loss of the bearing is very large due to high-speed friction and strong vibration. In order to reduce this friction loss, lubricating oil is needed to lubricate the bearing. The second guide groove stores and transmits a certain amount of lubricating oil, which flows into the bearing hole through the guide hole, so that a lubricating oil layer is formed between the shaft and the bearing, which can fully lubricate the bearing. In addition, the lubricating oil in the shaft hole can also flow out of the bearing hole through the guide hole to achieve a self-lubricating effect.

[0036] At the same time, the second guide groove can also distribute lubricating oil, ensuring that the lubricating oil can evenly cover the entire bearing surface and provide comprehensive protection for the bearing. The second guide groove is opened in the upper part of the bearing body. Due to the action of gravity, the lubricating oil flows into the bearing and automatically flows downward, making it convenient for the lubricating oil to fully fill the space between the shaft and the bearing.

[0037] In a further embodiment, the inner surface of the bearing body 1 includes a third guide groove 30 , and the third guide groove 30 is in the bearing hole and extends from the front end surface of the bearing to the rear end surface of the bearing.

[0038] Preferably, the third guide groove 30 and the second guide groove 20 correspond to each other in the axial position of the bearing body, and the second guide groove 20 includes a guide hole 40 therein, and the guide hole 40 penetrates from the second guide groove 20 to the third guide groove 30 .

[0039] The guide hole 40 guides the lubricating oil in the second guide groove 20 to the third guide groove 30, distributes the lubricating oil to the bearing hole through the third guide groove 30, guides the lubricating oil to be more evenly distributed on the bearing surface, reduces friction and wear, helps to form and maintain a stable lubricating oil film, and thus increases the lubrication performance of the bearing. In addition, the third guide groove serves as a buffer space for replenishing and discharging the lubricating oil between the contact surface of the shaft and the bearing during the operation of the shaft system, and plays a role in ensuring the thickness of the bearing oil film and maintaining the oil film pressure.

[0040] The design of the inner surface of the shaft hole of the bearing body 1 is as follows: Figure 3 As shown, Figure 3 A schematic diagram of the inner hole profile of a ship stern tube bearing for improving boundary lubrication effect according to an embodiment of the present invention is shown. The inner surface of the bearing body 1 is generally divided into four sections, which are, from right to left, a front micro-cone section 100, a cylindrical hole section 200, a conical hole section 300, and a rear micro-cone section 400. The right side of the figure represents the front end of the bearing, i.e., the bow direction of the ship, and the left side represents the rear end of the bearing, i.e., the stern direction of the ship, i.e., the stern direction of the ship.

[0041] The cylindrical hole section 100 is a cylindrical hole with a diameter of D, and its diameter is designed to match the diameter of the shaft 2 so that the shaft 2 can rotate therein and ensure that there is appropriate lubricating oil between the shaft 2 to play a supporting and lubricating role.

[0042] The front end micro-cone section 100 is a conical hole with a taper value of 1:Y, which means, for example, the ratio of the diameter difference ΔU between the upper and lower bottom circles to the height H of the cone (ΔU / H), that is, the ratio of the difference between the right side diameter and the left side diameter of the front end micro-cone section 100 to the length L1 of the front end micro-cone section is 1:Y.

[0043] The rear end micro-cone section 400 is a conical hole with a taper value of 1:Z, which means, for example, the ratio of the diameter difference ΔU between the upper and lower bottom circles to the height H of the cone (ΔU / H), that is, the ratio of the difference between the left diameter and the right diameter of the rear end micro-cone section 400 to the length L2 of the rear end micro-cone section is 1:Z.

[0044] The conical hole section 300 is a conical hole with a taper value of 1:X, which means, for example, the ratio of the diameter difference ΔU between the upper and lower bottom circles to the cone height H (ΔU / H), that is, the ratio of the difference between the left diameter and the right diameter of the conical hole section 300 to the length of the conical hole section is 1:X.

[0045] In the present application, the specific lengths and diameters of the front micro-cone section 100, the cylindrical hole section 200, the conical hole section 300 and the rear micro-cone section 400 are not limited, and their lengths and diameters match the lengths and diameters of the shaft and are adjusted according to actual usage. However, the relationship between the total length L of the cylindrical hole section 200 and the conical hole section 300 and the diameter D of the cylindrical hole section 200 is defined here, and the relationship is L greater than or equal to 2D, that is, L≥2D.

[0046] In one embodiment, the taper value 1:Y of the front micro-cone section 100 is greater than the taper value 1:X of the conical hole section 300, that is, 1:Y>1:X;

[0047] In another embodiment, the taper value 1:Z of the rear micro-cone section 400 is greater than the taper value 1:X of the conical hole section 300, that is, 1:Z>1:X;

[0048] In another embodiment, the taper value 1:Y of the front micro-cone section 100 and the taper value 1:Z of the rear micro-cone section 400 are both greater than the taper value 1:X of the conical hole section 300, that is, 1:Y>1:X and 1:Z>1:X.

[0049] As an important part of the shaft system, the micro-cone section of the ship's stern tube bearing has the main function of supporting the weight of the stern shaft and propeller to ensure the stable operation of the shaft system. The design of the micro-cone section helps to accurately position the stern shaft to prevent it from offsetting or shaking during operation, thereby maintaining the rotation accuracy of the shaft system.

[0050] The design of the tapered hole section can optimize the contact area and contact pressure distribution between the bearing and the stern shaft, which helps to form a more uniform lubrication film and improve the lubrication effect. After the propeller shaft and the inner hole of the bearing are assembled, the gap between the shaft and the bearing at the position of the tapered hole is not a constant value, but a gradual value. Because the gap between the shaft and the bearing is a gradual value, when the gap is filled with lubricating oil, the thickness of the oil film is also a gradual state. When the propeller shaft rotates, a mixed lubrication state will be generated at the bearing boundary, forming effective boundary lubrication, preventing the oil film on the boundary from failing, and avoiding high bearing temperatures caused by dry friction.

[0051] The purpose of the taper value 1:Y of the front micro-cone section 100 being greater than the taper value 1:X of the conical hole section 300 is that during the navigation of the ship, the propeller shaft will produce certain impact and vibration on the stern bearing. The design of a larger front micro-cone section can enhance the bearing capacity of the bearing, so that it can better adapt to such complex working conditions. In addition, the design of a larger front micro-cone section helps to change the inherent vibration characteristics of the shaft system, reduce the noise and wear of the shaft system caused by vibration, and improve the comfort and safety of the ship. In addition, the larger front micro-cone section facilitates the installation of the bearing.

[0052] Among them, the taper value 1:Z of the rear end micro-cone section 200 is greater than the taper value 1:X of the conical hole section 300. The purpose is that during the navigation of the ship, the propeller shaft will produce certain impact and vibration on the stern bearing. The design of the larger rear end micro-cone section can tolerate the deformation or bending of the shaft, so that a certain lubrication space is maintained between the bearing and the shaft, and the bearing capacity is enhanced, so that it can better adapt to such complex working conditions. In addition, the design of the larger rear end micro-cone section helps to change the inherent vibration characteristics of the shaft system, reduce the noise and wear of the shaft system caused by vibration, and improve the comfort and safety of the ship. In addition, the larger rear end micro-cone section facilitates the installation of the bearing.

[0053] In summary, by improving the design of the ship stern tube bearing, the inner surface of the bearing body is roughly divided into 4 sections, from right to left, the front micro-cone section, the cylindrical hole section, the conical hole section and the rear micro-cone section. When the propeller shaft rotates, a mixed lubrication state will be generated at the bearing boundary, forming effective boundary lubrication, preventing the oil film on the boundary from failing and avoiding high temperature of the bearing caused by dry friction.

[0054] In the description of this specification, the description with reference to the terms "an embodiment", "example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0055] In addition, it should be understood that although this specification is described according to implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0056] The above are preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A ship stern tube bearing with improved boundary lubrication effect, characterized in that: It includes a bearing body, which includes a bearing front end face, a bearing rear end face and an axial hole passing through the bearing front end face and the bearing rear end face, and the inner surface of the bearing body includes a front end micro-cone section, a cylindrical hole section, a conical hole section and a rear end micro-cone section in sequence, wherein the inner diameter of the conical hole section changes from small to large along the direction from the bearing front end face to the bearing rear end.

2. According to the ship stern tube bearing with improved boundary lubrication effect as claimed in claim 1, the sum of the lengths of the cylindrical hole section and the conical hole section is L, the inner diameter of the cylindrical hole section is D, wherein: L≥2D.

3. A ship stern tube bearing with improved boundary lubrication effect according to claim 1, wherein the taper value of the front micro-cone section is 1:Y, and the taper value of the conical hole section is 1:X, wherein: 1:Y>1:X.

4. A ship stern tube bearing with improved boundary lubrication effect according to claim 1, wherein the taper value of the rear micro-cone section is 1:Z, and the taper value of the conical hole section is 1:X, wherein: 1:Z>1:X.

5. A ship stern tube bearing with improved boundary lubrication effect according to claim 1, wherein the taper value of the front micro-cone section is 1:Y, the taper value of the rear micro-cone section is 1:Z, and the taper value of the conical hole section is 1:X, wherein: 1:Y>1:X and 1:Z>1:X.

6. According to the ship stern tube bearing with improved boundary lubrication effect as claimed in claim 1, the outer surface of the bearing body comprises a first guide groove, and the first guide groove extends from the front end surface of the bearing to the rear end surface of the bearing.

7. According to the ship stern tube bearing with improved boundary lubrication effect as claimed in claim 1, the outer surface of the bearing body comprises a second guide groove, and the second guide groove extends from the front end surface of the bearing to the rear end surface of the bearing.

8. According to the ship stern tube bearing with improved boundary lubrication effect as claimed in claim 1, the inner surface of the bearing body comprises a third guide groove, and the third guide groove extends from the front end surface of the bearing to the rear end surface of the bearing.

9. A ship stern tube bearing with improved boundary lubrication effect according to claim 7, wherein the second guide groove comprises a guide hole, and the guide hole penetrates from the second guide groove to the inner surface of the bearing body.

10. A ship stern tube bearing with improved boundary lubrication effect according to claims 7 and 8, wherein the second guide groove and the third guide groove correspond to each other in the axial position of the bearing body, and the second guide groove includes a guide hole, and the guide hole penetrates from the second guide groove to the third guide groove.

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