A kind of for marine low-speed diesel engine cylinder head stud protection device and cylinder

Abstract

This invention belongs to the technical field of marine low-speed diesel engines, and discloses a cylinder head stud protection device and cylinder for a marine low-speed diesel engine. The cylinder for a marine low-speed diesel engine includes a cylinder head, studs, and a cylinder head stud protection device. The cylinder head has a mounting hole, and the stud extends into the mounting hole with a gap between it and the inner wall of the mounting hole. The cylinder head stud protection device includes an inner bushing, an outer bushing, an elastic element, and a locking assembly. The cylinder head stud protection device is installed on the stud below the cylinder head. The inner and outer bushings are embedded in the gap, with the outer bushing abutting against the inner wall of the mounting hole and the inner bushing abutting against the stud, fixing the stud to the cylinder head and preventing the stud from popping out. Furthermore, the elastic element pushes the outer bushing upwards along the axial direction of the stud. When the inner bushing loosens and slides under strong vibration conditions, the outer bushing remains abutting against the inner wall of the mounting hole under the action of the elastic element, achieving further locking.

Description

Technical Field

[0001] This invention relates to the field of marine low-speed diesel engine technology, and in particular to a cylinder head stud protection device and cylinder for marine low-speed diesel engines. Background Technology

[0002] Marine low-speed diesel engines are the core of marine power, and the reliability of the connection between the cylinder head and cylinder block directly affects the operational safety of the main engine and the safety of personnel. Cylinder head studs, as key fasteners connecting the cylinder head and cylinder block, have one end inserted into the cylinder block and the other end passing through the cylinder head and secured by a hydraulic nut. Because marine low-speed diesel engine cylinder head studs typically have a large length-to-diameter ratio, often exceeding 1:35, and some engine models experience significant vibration loads during operation, some studs may experience brittle fracture due to insufficient toughness after long-term service.

[0003] In actual operation, once the cylinder head studs experience brittle fracture, the broken stud segments may eject at high speed under the release of preload and vibration, posing a serious threat to the personal safety of operators. At the same time, they may impact surrounding components such as the cylinder head, valve mechanism, and high-pressure oil pipes, causing secondary damage or even triggering more serious safety accidents.

[0004] In existing technologies, to address the risk of cylinder head stud breakage, adjacent studs are typically connected in series with connectors to reduce the probability of breakage through load sharing. The core principle is to prevent breakage altogether. However, once a stud breaks, this structure fails to provide effective safety protection. Some methods employ bushings fitted around the stud; when the stud breaks, the bushing moves upwards with the stud and forms frictional braking with the cylinder block, thus limiting displacement. However, the locking force is limited by the coefficient of friction, posing a risk of loosening under strong vibration conditions. Furthermore, the impact energy is entirely borne by a single structure, easily leading to structural overload failure. Summary of the Invention

[0005] The purpose of this invention is to provide a cylinder head stud protection device and cylinder for marine low-speed diesel engines. The cylinder head stud protection device for marine low-speed diesel engines has high locking strength in both the radial and axial directions of the studs, preventing loosening, and has a compact structure with a small footprint.

[0006] To achieve this objective, the present invention adopts the following technical solution: On the one hand, a cylinder head stud protection device for marine low-speed diesel engines is provided, comprising: Inner sleeve, the inner sleeve being configured to be fitted onto the stud and conform to the outer wall of the stud; An outer bushing is fitted onto an inner bushing along the axial direction of the stud. The outer bushing is slidably connected to the inner bushing. The outer wall of the outer bushing has a tapered structure. The inner bushing and the outer bushing are configured to be able to fit into the gap between the stud and the inner wall of the mounting hole. The outer bushing abuts against the inner wall of the mounting hole, and the inner bushing abuts against the stud. An elastic element is connected to the inner bushing, and the outer bushing is connected to the elastic element. The elastic element is capable of extending and retracting along the axial direction of the stud. A locking assembly is sleeved on the inner bushing and is used to fix the inner bushing to the stud.

[0007] In some possible implementations, both the inner liner and the outer liner are two-part structures.

[0008] In some possible implementations, the inner bushing includes a retaining ring and a plurality of first claws, all of which are circumferentially spaced around the stud and connected to the retaining ring, and the first claws extend axially along the stud and are elastically deformable. The outer bushing includes a plurality of second claws, all of which are circumferentially spaced around the stud and connected to the elastic element. The second claws extend axially along the stud and are elastically deformable.

[0009] In some possible implementations, the first jaw and the second jaw are misaligned.

[0010] In some possible implementations, the elastic element is annular and has a two-part structure, and the elastic element is sleeved on the inner liner.

[0011] In some possible implementations, the locking assembly includes two semi-circular hose clamps and two fastening screws, the two semi-circular hose clamps forming a ring structure and fitting onto the inner liner, and the two fastening screws used to lock the two semi-circular hose clamps.

[0012] In some possible implementations, the outer wall of the inner bushing is provided with a placement groove along the circumference of the stud, and the two semi-circular hose clamps are disposed in the placement groove.

[0013] In some possible implementations, the inner wall of the liner is provided with a ceramic coating.

[0014] In some possible implementations, the thickness of the ceramic coating ranges from 0.04 mm to 0.06 mm.

[0015] On the other hand, a cylinder for a marine low-speed diesel engine is provided, including a cylinder head, a stud, and the aforementioned stud protection device for the cylinder head of a marine low-speed diesel engine. The cylinder head is provided with a mounting hole, the stud extends into the mounting hole and has a gap between it and the inner wall of the mounting hole, and the inner bushing and the outer bushing can extend into the gap and abut against the inner wall of the mounting hole and the stud.

[0016] The beneficial effects of this invention are: This invention provides a cylinder head stud protection device and cylinder for a marine low-speed diesel engine. The cylinder for the marine low-speed diesel engine includes a cylinder head, studs, and a cylinder head stud protection device. The cylinder head has mounting holes, and the studs extend into the mounting holes with a gap between them and the inner wall of the holes. The cylinder head stud protection device includes an inner bushing, an outer bushing, an elastic element, and a locking assembly. An inner bushing is fitted onto the stud and conforms to its outer wall. An outer bushing is fitted onto the inner bushing. Along the axial direction of the stud, the outer bushing is slidably connected to the inner bushing. The outer wall of the outer bushing has a tapered structure. The inner and outer bushings can be embedded in the gap between the stud and the inner wall of the mounting hole. The outer bushing abuts against the inner wall of the mounting hole, and the inner bushing abuts against the stud. An elastic element is connected to the inner bushing, and the outer bushing is connected to the elastic element. The elastic element can extend and retract along the axial direction of the stud. A locking assembly is fitted onto the inner bushing to secure the inner bushing to the stud. During installation, this stud protection device for marine low-speed diesel engine cylinder heads is installed on the stud below the cylinder head. The inner and outer bushings are embedded in the gap and abut against the inner wall of the mounting hole and the stud, fixing the stud to the cylinder head and preventing the stud from popping out. Furthermore, the elastic element pushes the outer bushing upward along the axial direction of the stud. Even if the inner bushing loosens and slides under strong vibration, the elastic element ensures the outer bushing remains pressed against the inner wall of the mounting hole, further locking the stud axially. The elastic element also acts as a buffer, with the impact energy shared by the inner bushing, outer bushing, and elastic element, preventing excessive impact from damaging the stud protection device for marine low-speed diesel engine cylinder heads. The outer wall of the outer bushing is tapered, facilitating its insertion into the gap and ensuring complete contact between the outer bushing and the inner wall of the mounting hole. This stud protection device for marine low-speed diesel engine cylinder heads provides high locking strength in both the radial and axial directions of the stud, and features a compact structure with minimal space requirements. Attached Figure Description

[0017] Figure 1 This is a front view of the cylinder head stud protection device for marine low-speed diesel engines provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the cylinder head stud protection device for marine low-speed diesel engines provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the first semi-circular bushing involved in an embodiment of the present invention; Figure 4 This is a cross-sectional view of the cylinder head stud protection device for marine low-speed diesel engines provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the locking assembly involved in the embodiments of the present invention.

[0018] In the picture: 1. Inner bushing; 11. First semi-circular bushing; 12. Fixing ring; 13. First claw; 14. Placement groove; 2. Outer bushing; 21. Second semi-circular bushing; 22. Second claw; 23. Connecting edge; 3. Elastic element; 4. Locking assembly; 41. Semi-circular hose clamp; 42. Fastening screw; 43. Fixing plate. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0020] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0021] In the description of this invention, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0022] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0023] like Figures 1 to 5As shown, this embodiment provides a cylinder for a marine low-speed diesel engine. The cylinder for a marine low-speed diesel engine includes a cylinder head, studs, and a cylinder head stud protection device. The cylinder head has mounting holes, and the studs extend into the mounting holes with a gap between them and the inner wall of the holes. The cylinder head stud protection device includes an inner bushing 1, an outer bushing 2, an elastic element 3, and a locking assembly 4. Inner bushing 1 is fitted onto the stud and fits against the outer wall of the stud. Outer bushing 2 is fitted onto inner bushing 1. Along the axial direction of the stud, outer bushing 2 is slidably connected to inner bushing 1. The outer wall of outer bushing 2 has a tapered structure. Inner bushing 1 and outer bushing 2 can be embedded in the gap between the stud and the inner wall of the mounting hole. Outer bushing 2 is pressed against the inner wall of the mounting hole, and inner bushing 1 is pressed against the stud. Elastic element 3 is connected to inner bushing 1, and outer bushing 2 is connected to elastic element 3. Elastic element 3 can extend and retract along the axial direction of the stud. Locking assembly 4 is fitted onto inner bushing 1. Locking assembly 4 is used to fix inner bushing 1 onto the stud.

[0024] During installation, the cylinder head stud protection device for marine low-speed diesel engines is mounted on the studs below the cylinder head. The inner bushing 1 and outer bushing 2 are embedded in the gap, pressing against the inner wall of the mounting hole and the stud, securing the stud to the cylinder head and preventing it from popping out. Furthermore, the elastic element 3 pushes the outer bushing 2 upwards along the axial direction of the stud. Even if the inner bushing 1 loosens and slides under strong vibration, the outer bushing 2 remains pressed against the inner wall of the mounting hole under the action of the elastic element 3, further locking it axially. The elastic element 3 also acts as a buffer, with the impact energy shared by the inner bushing 1, outer bushing 2, and elastic element 3, preventing excessive impact that could damage the cylinder head stud protection device for marine low-speed diesel engines. The outer wall of the outer bushing 2 is designed with a tapered structure to facilitate embedding the outer bushing 2 into the gap, ensuring complete contact between the outer bushing 2 and the inner wall of the mounting hole. The cylinder head stud protection device for marine low-speed diesel engines has high locking strength in both the radial and axial directions of the stud, and has a compact structure and occupies little space.

[0025] Specifically, the inner diameter of the inner bushing 1 is the same as the outer diameter of the stud. The outer wall of the inner bushing 1 has a tapered structure, and the inner wall of the outer bushing 2 also has a tapered structure, fitting snugly against the outer wall of the inner bushing 1. The length of the outer bushing 2 along the axial direction of the stud is less than or equal to the length of the inner bushing 1 along the axial direction of the stud, allowing the outer bushing 2 to be inserted into the gap. The inner bushing 1 and the stud have a large contact area, giving the inner bushing 1 and the stud high fixing strength. Both the inner bushing 1 and the outer bushing 2 are made of 25CrMoA alloy steel, giving the inner bushing 1 and the outer bushing 2 high structural strength and impact resistance.

[0026] Because vibrations occur during cylinder operation, friction arises between the inner bushing 1 and the stud. Optionally, a ceramic coating is applied to the inner wall of the inner bushing 1. This ceramic coating possesses advantages such as high strength, good density, high hardness, wear resistance, and corrosion resistance, thereby improving the service life of the inner bushing 1 and the fixing strength between the inner bushing 1 and the stud. Specifically, the ceramic coating is applied using a supersonic spraying process. Coatings applied using this supersonic spraying process exhibit higher bonding strength, lower porosity, and higher density.

[0027] Optionally, the thickness of the ceramic coating ranges from 0.04mm to 0.06mm. This ensures the ceramic coating has a certain thickness to guarantee its strength, while avoiding excessive thickness that would increase spraying time and cost. It also ensures that the inner liner 1 can be fitted onto the stud after spraying.

[0028] Optionally, see Figures 1 to 3 Both the inner bushing 1 and the outer bushing 2 are two-part structures, which facilitates their installation. Specifically, the inner bushing 1 includes two first semi-circular bushings 11, and the outer bushing 2 includes two second semi-circular bushings 21. The two first semi-circular bushings 11 are identical in structure and arranged opposite each other, forming a ring structure, and are fixed by a locking assembly 4. The two second semi-circular bushings 21 are identical in structure and arranged opposite each other, forming a ring structure, and are fixed by an elastic element 3. In other embodiments, the inner bushing 1 and the outer bushing 2 may also be three-part or four-part structures, not limited to this embodiment.

[0029] Optionally, the inner bushing 1 includes a retaining ring 12 and multiple first claws 13. All the first claws 13 are spaced apart around the stud and connected to the retaining ring 12. The first claws 13 extend axially along the stud and are elastically deformable. The outer bushing 2 includes multiple second claws 22. All the second claws 22 are spaced apart around the stud and connected to the elastic element 3. The second claws 22 extend axially along the stud and are elastically deformable. This arrangement allows the diameters of the inner bushing 1 and the outer bushing 2 to be adaptively adjusted, improving the fit between the inner bushing 1 and the stud, and improving the fit between the outer bushing 2 and the inner bushing 1 and the inner wall of the mounting hole, thereby increasing the fixing strength.

[0030] Specifically, see Figures 2 to 4The first claw 13 is connected to one end of the fixing ring 12 along its own axial direction. The fixing ring 12 has a two-half structure, which is composed of two semi-circular sub-rings joined together. There are six first claws 13, and three first claws 13 are connected to each sub-ring, forming a first semi-circular sub-shroud 11. The outer wall of the first claw 13 has a conical structure. There are six second claws 22, and each of the two second semi-circular sub-shrouds 21 includes three second claws 22. One end of the three second claws 22 is integrally connected by a connecting edge 23, which is connected to the elastic element 3. In other embodiments, the number of first claws 13 and second claws 22 is set according to specific circumstances and is not limited to this embodiment. In other embodiments, the outer bushing 2 includes six second claws 22, and the six second claws 22 are directly connected to the elastic element 3.

[0031] Optionally, the first jaw 13 and the second jaw 22 are staggered. This staggered arrangement of the first jaw 13 and the second jaw 22 can improve the uniformity of force distribution on the inner bushing 1 and the outer bushing 2.

[0032] Optionally, the elastic element 3 is annular and has a two-half structure, and is fitted onto the inner sleeve 1. The annular shape of the elastic element 3 facilitates connection between the second claw 22 and the elastic element 3, and provides good connection stability. The two-half structure of the elastic element 3 facilitates its installation onto the inner sleeve 1. Specifically, the elastic element 3 is installed on the fixing ring 12, and the elastic element 3 and the fixing ring 12 can be fixed by adhesive or snap-fit, etc., which is not limited in this embodiment. In other embodiments, a limiting edge protrudes along the circumference of the fixing ring 12, the elastic element 3 is fitted onto the inner sleeve 1, one end of the elastic element 3 is connected to the second claw 22, and the other end is connected to the limiting edge. Further, the elastic element 3 can be a spring, and six elastic elements 3 are provided, arranged circumferentially around the stud and connected one-to-one with the second claw 22.

[0033] Optionally, see Figure 1 and Figure 5The locking assembly 4 includes two semi-circular hose clamps 41 and two fastening screws 42. The two semi-circular hose clamps 41 form a ring structure and are fitted onto the inner bushing 1. The two fastening screws 42 are used to lock the two semi-circular hose clamps 41. The two semi-circular hose clamps 41 facilitate installation. The two fastening screws 42 ensure more even force distribution on the two semi-circular hose clamps 41. Specifically, the locking assembly 4 also includes two fixing plates 43. The two fixing plates 43 are respectively located on opposite sides of the two semi-circular hose clamps 41. One end of each fixing plate 43 has a through hole, and the other end has a threaded hole. The fastening screws 42 pass through the through hole of one fixing plate 43 and are threadedly connected to the threaded hole of the other fixing plate 43. The two fastening screws 42 and the two fixing plates 43 form a ring structure. Tightening the fastening screw 42 can press the fixing plate 43 against the semi-circular hose clamp 41, thereby pressing the two semi-circular hose clamps 41 against the inner bushing 1, and then pressing the inner bushing 1 against the stud. In other embodiments, the locking assembly 4 includes two semi-circular hose clamps 41 and a fastening screw 42, with one end of the two semi-circular hose clamps 41 rotatably connected and the other end fixed by the fastening screw 42. In other embodiments, both ends of the semi-circular hose clamps 41 are provided with connecting ear plates, one connecting ear plate is provided with a through hole, and the other connecting ear plate is provided with a threaded hole, and the two semi-circular hose clamps 41 are directly connected by two fastening screws 42.

[0034] Optionally, see Figure 3 The outer wall of the inner bushing 1 is provided with a placement groove 14 around the stud, and two semi-circular hose clamps 41 are placed in the placement groove 14. Placing the two semi-circular hose clamps 41 in the placement groove 14 facilitates the positioning of the two semi-circular hose clamps 41, facilitates the installation of the two semi-circular hose clamps 41, and prevents the locking component 4 from falling off the inner bushing 1.

[0035] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A stud protection device for the cylinder head of a marine low-speed diesel engine, characterized in that, include: Inner sleeve (1), the inner sleeve (1) is configured to be sleeved on the stud and fit against the outer wall of the stud; Outer bushing (2), the outer bushing (2) is sleeved on the inner bushing (1), along the axial direction of the stud, the outer bushing (2) is slidably connected to the inner bushing (1), the outer wall of the outer bushing (2) is tapered, the inner bushing (1) and the outer bushing (2) are configured to be able to be embedded in the gap between the stud and the inner wall of the mounting hole, the outer bushing (2) abuts against the inner wall of the mounting hole, and the inner bushing (1) abuts against the stud; An elastic element (3) is connected to the inner bushing (1), and the outer bushing (2) is connected to the elastic element (3). The elastic element (3) is capable of extending and retracting along the axial direction of the stud. Locking assembly (4) is sleeved on the inner bushing (1) and is used to fix the inner bushing (1) to the stud.

2. The cylinder head stud protection device for marine low-speed diesel engines according to claim 1, characterized in that, Both the inner liner (1) and the outer liner (2) are two-part structures.

3. The cylinder head stud protection device for marine low-speed diesel engines according to claim 1, characterized in that, The inner sleeve (1) includes a retaining ring (12) and a plurality of first claws (13). All the first claws (13) are arranged circumferentially around the stud and are connected to the retaining ring (12). The first claws (13) extend axially along the stud and are elastically deformable. The outer bushing (2) includes a plurality of second claws (22), all of which are circumferentially spaced around the stud and connected to the elastic member (3). The second claws (22) extend axially along the stud and are elastically deformable.

4. The cylinder head stud protection device for marine low-speed diesel engines according to claim 3, characterized in that, The first claw (13) and the second claw (22) are misaligned.

5. The cylinder head stud protection device for marine low-speed diesel engines according to claim 3, characterized in that, The elastic element (3) is ring-shaped and has a two-half structure, and the elastic element (3) is sleeved on the inner liner (1).

6. The cylinder head stud protection device for marine low-speed diesel engines according to claim 1, characterized in that, The locking assembly (4) includes two semi-circular hose clamps (41) and two fastening screws (42). The two semi-circular hose clamps (41) are arranged in a ring structure and fitted onto the inner liner (1). The two fastening screws (42) are used to lock the two semi-circular hose clamps (41).

7. The cylinder head stud protection device for marine low-speed diesel engines according to claim 6, characterized in that, The outer wall of the inner bushing (1) is provided with a placement groove (14) around the stud, and the two semi-circular hose clamps (41) are placed in the placement groove (14).

8. The cylinder head stud protection device for marine low-speed diesel engines according to claim 1, characterized in that, The inner wall of the inner liner (1) is provided with a ceramic coating.

9. The cylinder head stud protection device for marine low-speed diesel engines according to claim 8, characterized in that, The thickness of the ceramic coating ranges from 0.04 mm to 0.06 mm.

10. A cylinder for a marine low-speed diesel engine, characterized in that, The device includes a cylinder head, studs, and a stud protection device for a marine low-speed diesel engine cylinder head as described in any one of claims 1-9. The cylinder head is provided with a mounting hole, the studs extend into the mounting hole and are provided with a gap between them and the inner wall of the mounting hole, and the inner bushing (1) and the outer bushing (2) can extend into the gap and abut against the inner wall of the mounting hole and the studs.

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