Centering device and method for the tensioning of the cylinder head bolts of a marine main engine

Abstract

A centering device and method for tightening the cylinder head bolt of a marine main engine, comprising a lower ring assembly, an upper ring assembly and a plurality of wedge-shaped positioning frame plates; wherein the lower ring assembly is clamped on the cylinder head bolt below the cylinder head, the upper ring assembly is screwed on the lower ring assembly and surrounds the outer periphery of the cylinder head bolt between the lower ring assembly and the cylinder head, the wedge-shaped positioning frame plates gradually narrow from the bottom to the top, and the plurality of wedge-shaped positioning frame plates are hinged to the upper end of the upper ring assembly; the upper ring assembly is lifted by rotating on the lower ring assembly, pushing the wedge-shaped positioning frame plates to move upwards and synchronously inserting the top into the gap between the cylinder head bolt and the bolt hole of the cylinder head, and as the wedge-shaped positioning frame plates are inserted deeper, the cylinder head bolt is gradually squeezed and positioned to the center of the bolt hole. The positioning device is used to rely on the cylinder head bolt itself to achieve accurate positioning of the cylinder head bolt before pumping, and to ensure the quality of the main engine, improve production efficiency and save production cost.

Description

Technical Field

[0001] This invention relates to the assembly process of marine diesel engines, specifically to a centering device and method for pumping tightness of cylinder head bolts in marine main engines, belonging to the field of marine diesel engine manufacturing technology. Background Technology

[0002] During the pre-assembly and inspection submission of marine diesel engine main units, the cylinder head bolts need to be tightened and loosened frequently. Tightening the cylinder head bolts properly is an important step and foundation for the main unit assembly, commissioning and operation. Inadequate tightening will affect the quality and performance of the main unit.

[0003] Currently, the pump-tightening process for cylinder head bolts suffers from a problem: the upper end of the bolt offsets from the center axis of the cylinder head bolt hole after pump tightening, and the offset direction varies for each bolt, affecting the overall quality of the main engine and subsequent assembly work. Excessive offset of the upper end of the cylinder head bolts will affect the performance of the bolt itself and the achieved pre-tightening effect. Secondly, during main engine lifting, the cylinder block assembly lifting tool or the entire machine lifting tool needs to be installed on multiple cylinder head bolts. If multiple bolts are irregularly offset, it will seriously affect the installation of the lifting tool, often resulting in installation failures. For example, in a certain ship main engine assembly project, after the cylinder head bolts were pump-tightened during the pre-assembly stage, the cylinder block assembly lifting tool was installed. Each lifting tool was installed on 6 cylinder head bolts. Due to the offset caused by the pump tightening of the cylinder head bolts, the 6 bolt holes on the lifting tool could not be simultaneously aligned with the cylinder head bolts, making normal installation impossible. Some cylinder head bolts had to be pumped loose, adjusted, re-pumped tight, and then the lifting tool reinstalled, which was not only time-consuming and labor-intensive but also affected the overall quality of the main engine. Therefore, accurate positioning before pump-tightening the cylinder head bolts is crucial; however, there is currently no effective positioning method. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies in the absence of accurate and effective positioning methods before the main engine cylinder head bolts are pumped tight, and to provide a centering device and method for pumping tight the cylinder head bolts of marine main engines. By installing the centering device in the upper part of the cylinder head bolts, the positioning work of the cylinder head bolts during main engine assembly can be completed conveniently and accurately, achieving the effect of simple structure and easy use.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A centering device for pump-tightening cylinder head bolts in marine main engines, the main engine including cylinder head bolts that are pump-tightened through bolt holes in the cylinder head; characterized in that: the centering device is detachably mounted on the cylinder head bolts, including a lower ring assembly, an upper ring assembly, and a plurality of wedge-shaped positioning plates; the lower ring assembly is clamped around the cylinder head bolts below the cylinder head, the upper ring assembly is threaded onto the lower ring assembly and surrounds the outer periphery of the cylinder head bolts between the lower ring assembly and the cylinder head, the wedge-shaped positioning plates... The positioning bracket plate gradually narrows from bottom to top. Several wedge-shaped positioning bracket plates are evenly positioned and hinged at the bottom to the periphery of the upper end of the upper ring assembly, and swing on the radial plane of the cylinder head bolt. The upper ring assembly is spirally lifted by rotating on the lower ring assembly, pushing the wedge-shaped positioning bracket plate upward and simultaneously inserting its top into the gap between the cylinder head bolt and the bolt hole of the cylinder head. As the wedge-shaped positioning bracket plate is inserted deeper, the cylinder head bolt is gradually pressed and positioned to the center position of the bolt hole.

[0007] Furthermore, the lower ring assembly is formed by the mating of a right ring clamp and a left ring clamp. The upper outer periphery is provided with an external thread for connecting the upper ring assembly, and the two sides of the lower outer periphery are respectively provided with a hinge assembly and a locking assembly. The right ring clamp and the left ring clamp rotate around the hinge assembly to open and close, and are locked by the locking assembly, thereby immovably clamping the lower ring assembly onto the cylinder head bolt.

[0008] Furthermore, the lower inner wall of the lower ring assembly is provided with a rubber layer for protection and to increase friction.

[0009] Furthermore, the upper ring assembly is formed by the mating of a right ring and a left ring. The lower inner wall is provided with an internal thread for connecting the lower ring assembly. The two sides of the outer periphery are respectively provided with a hinge assembly and a locking assembly. The right ring and the left ring rotate around the hinge assembly to open and close, and are locked by the locking assembly.

[0010] Furthermore, the hinge assembly consists of a vertical round pin and a left pin seat and a right pin seat that pass through it, and the locking assembly consists of a horizontal bolt and two connecting lugs that connect it.

[0011] Furthermore, the outer periphery of the upper end of the upper ring assembly is provided with a plurality of hinge seats evenly distributed for hinged to the wedge-shaped positioning frame plate.

[0012] Furthermore, the surface of the wedge-shaped positioning bracket plate is parallel to the radial plane of the cylinder head bolt along the axial direction of the cylinder head bolt and has an inclined wedge edge on the outer side. As the inclined wedge edge extends, the wedge-shaped positioning bracket plate gradually narrows from the bottom to the top.

[0013] Another technical solution of the present invention is:

[0014] A centering method for tightening cylinder head bolts in marine main engines using the aforementioned centering device comprises the following steps:

[0015] The first step is to install the cylinder head by pre-installing the nuts on the cylinder head bolts without tightening them, and then inserting and locking the lower ring assembly at a suitable height position on the cylinder head bolts below the cylinder head.

[0016] The second step is to fit the upper ring assembly onto the cylinder head bolt between the lower ring assembly and the cylinder head and lock it in place. Then, the upper ring assembly and the lower ring assembly are screwed together. The height of the positioning device on the cylinder head bolt is adjusted to maintain a suitable distance from the cylinder head. The lower ring assembly is locked and clamped to the cylinder head bolt, thereby completing the installation of the centering device on the cylinder head bolt.

[0017] Third, swing all the wedge-shaped positioning plates upward and against the cylinder head bolts, rotate the upper ring assembly to slowly rise, so that the top of each wedge-shaped positioning plate is simultaneously inserted into the gap between the cylinder head bolt and the bolt hole of the cylinder head. As the wedge-shaped positioning plates continue to rise, the cylinder head bolt is gradually squeezed towards the center of the bolt hole of the cylinder head until the cylinder head bolt is accurately positioned in the center of the bolt hole.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. Before the cylinder head bolts are pumped tight, the center line of the cylinder head bolts can be accurately positioned to coincide with the center line of the cylinder head bolt holes, avoiding the occurrence of the cylinder head bolts shifting off the bolt holes after pumping tightness. This saves a lot of repetitive rework steps, reduces production time, saves production costs, and improves production efficiency.

[0020] 2. Precise positioning of the cylinder head bolts before pumping them into place was achieved, ensuring that the cylinder head bolts were in a completely perpendicular axial position after pumping them into place, thereby guaranteeing the assembly quality of the main unit.

[0021] 3. The positioning device has a simple structure, is easy to use, safe and reliable, highly versatile, and practical.

[0022] In summary, this invention employs a positioning device that relies on the cylinder head bolts themselves to achieve precise positioning of the cylinder head bolts before pump tightening, thereby ensuring the quality of the main unit, improving production efficiency, and saving production costs. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the present invention.

[0024] Figure 2 This is a schematic diagram of the lower circular ring assembly.

[0025] Figure 3 This is a schematic diagram of the upper ring assembly.

[0026] Figure 4 This is a schematic diagram of the method of the present invention.

[0027] In the picture,

[0028] 1—Lower ring assembly, 11—Right ring clamp, 12—Left ring clamp, 13—External thread, 2—Upper ring assembly, 21—Right ring, 22—Left ring, 23—Internal thread, 3—Wedge positioning bracket plate, 4—Hinge assembly, 5—Locking assembly, 6—Hinge seat, A—Cylinder head, B—Cylinder head bolt. Detailed Implementation

[0029] This invention is used for the centering operation before tightening the cylinder head bolts of a marine main engine. Please refer to [link / reference]. Figure 1 The main engine of the ship includes a cylinder head A that is pumped tight by cylinder head bolts B.

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the scope of protection of the present invention.

[0031] Please refer to the following: Figure 1 and Figure 4 The centering device is detachably mounted on the cylinder head bolt B below the cylinder head A, and includes a lower ring assembly 1, an upper ring assembly 2, and several wedge-shaped positioning plates 3. The lower ring assembly 1 is an annular component that clamps and immovably locks onto the outer periphery of the cylinder head bolt B. The upper ring assembly 2 is an annular component that is threaded onto the lower ring assembly 1 and surrounds the outer periphery of the cylinder head bolt B. The wedge-shaped positioning plates 3 are flat components that gradually narrow from bottom to top, with a wedge edge 31 on the outer side. The four wedge-shaped positioning plates 3 are evenly hinged at the bottom to the periphery of the upper end of the upper ring assembly 2. After hinge, the surface of the wedge-shaped positioning plates 3 is parallel to the radial plane of the cylinder head bolt B along the axial direction of the cylinder head bolt B, and the wedge edge 31 is located on the outer side. The wedge-shaped positioning plates 3 can swing about the hinge point on the radial plane.

[0032] Please see Figure 2The lower ring assembly 1 is a cylindrical component formed by the mating of a right ring clamp 11 and a left ring clamp 12. The upper outer circumference of this cylindrical component has an integrally machined external thread 13 for connecting to the upper ring assembly 2. A hinge assembly 4 is provided on one side of the lower outer circumference of the cylindrical component, and a locking assembly 5 is provided on the other side. Both the hinge assembly 4 and the locking assembly 5 are located at the mating point of the right ring clamp 11 and the left ring clamp 12. The lower inner wall of the lower ring assembly 1 has a rubber layer for contact with the cylinder head. Bolt B is in contact to protect the surface of the cylinder head bolt B from damage, while increasing the friction when the lower ring assembly 1 clamps the cylinder head bolt B; the right ring clamp 11 and the left ring clamp 12 are hinged to each other on one side by the hinge assembly 4, and locked on the other side by the locking assembly 5 to immovably clamp the lower ring assembly 1 onto the cylinder head bolt B. The right ring clamp 11 and the left ring clamp 12 can rotate around the hinge assembly 4 and are opened and closed by the locking assembly 5.

[0033] Please see Figure 3 The upper ring assembly 2 is a cylindrical component formed by the mating of a right ring member 21 and a left ring member 22. The inner wall of the lower part of the cylindrical component is provided with an internal thread 23 that is machined into one piece for connecting the lower ring assembly 1. A hinge assembly 4 is provided on one side of the outer periphery of the lower part of the cylindrical component, and a locking assembly 5 is provided on the other side. Both the hinge assembly 4 and the locking assembly 5 are located at the mating point of the right ring member 21 and the left ring member 22. The right ring member 21 and the left ring member 22 are hinged to each other on one side by the hinge assembly 4 and locked on the other side by the locking assembly 5 to form a cylindrical upper ring assembly 2. The right ring member 21 and the left ring member 22 can rotate around the hinge assembly 4 and are opened and closed by the locking assembly 5. The outer periphery of the upper end of the right ring member 21 and the left ring member 22 is provided with a hinge seat 6 for hinged to the wedge-shaped positioning frame plate 3.

[0034] Please refer to the following: Figure 1 , Figure 2 and Figure 3 The hinge assembly 4 consists of a vertical round pin and a left pin seat and a right pin seat that pass through it, and the locking assembly 5 consists of a horizontal bolt and two connecting lugs that connect it.

[0035] Please see Figure 3As the wedge edge 31 extends, the wedge-shaped positioning plate 3 gradually narrows from bottom to top. The wedge-shaped positioning plate 3 is hinged to the hinge seat 6 at the upper end of the upper ring assembly 2 via hinge pins, and their positions are evenly distributed at 90° intervals. When the four wedge-shaped positioning plates 3 swing around the hinge point in the radial plane until they are close to the cylinder head bolt B at the top, the upper ring assembly 2 is rotated and spirally lifted on the lower ring assembly 1. The upper ring assembly 2 pushes the four wedge-shaped positioning plates 3 upwards and simultaneously inserts them into the gap between the cylinder head bolt B and the bolt hole of the cylinder head A. The inner side of the top of the wedge-shaped positioning plate 3 is close to the cylinder head bolt B, and the outer wedge edge 31 is close to the inner wall of the bolt hole of the cylinder head A. As the height of the upper ring assembly 2 changes, due to the action of the wedge edge 31, the cylinder head bolt B is finally pressed and positioned at the center of the bolt hole of the cylinder head A.

[0036] The positioning device described in this invention, when used in conjunction with existing pump-tightening tools, can pump-tighten cylinder head bolts in two stages, aligning the centerline of the cylinder head bolts with the centerline of the bolt holes in the cylinder head. The first stage is a positioning step, where the positioning device is used to position the cylinder head bolts at the center of the bolt holes; then, in the second stage, the cylinder head bolts are pumped tight, and finally, the positioning device is removed.

[0037] Please see Figure 4 The centering method for tightening cylinder head bolts in marine main engines, as described in this invention, comprises the following steps:

[0038] First, install the cylinder head A and cylinder head bolts B, pre-installing the nuts without tightening them; then, slip the lower ring assembly 1 onto the cylinder head bolts B below the cylinder head A, place it at a suitable height, and lock it using the locking assembly 5.

[0039] The second step is to fit the upper ring assembly 2 onto the cylinder head bolt B between the lower ring assembly 1 and the lower plane of the cylinder head A, close it, and lock it with the locking assembly 5. Then, screw the upper ring assembly 2 onto the lower ring assembly 1 and adjust the height of the entire device on the cylinder head bolt B. Note that the height should not be too low or too high. It needs to be placed in a suitable position in conjunction with the pump's tightening stroke. After confirming the height, lock the lower ring assembly 1 so that the lower ring assembly 1 is clamped and fixed on the cylinder head bolt B, thereby completing the installation and fixing of the centering device on the cylinder head bolt B.

[0040] The third step involves swinging the four wedge-shaped positioning plates 3 in the radial plane until they are close to the cylinder head bolt B. Then, the upper ring assembly 2 is rotated and slowly raised so that the wedge-shaped positioning plates 3 are simultaneously inserted into the gap between the cylinder head bolt B and the bolt hole of the cylinder head A. As the wedge-shaped positioning plates 3 rise, the cylinder head bolt B is gradually squeezed toward the center of the bolt hole of the cylinder head A. Finally, after reaching a certain height, the cylinder head bolt B is accurately positioned at the center of the bolt hole.

[0041] After the positioning operation is completed, tighten the nut and use a hydraulic tensioner to tighten the cylinder head bolt B.

[0042] The scope of protection claimed by this invention is not limited to the above embodiments, but should also include other variations and alternatives that are obvious to this invention.

Claims

1. A centering device for pumping tightness of cylinder head bolts in a marine main engine, the marine main engine including cylinder head bolts that are pumped through bolt holes in the cylinder head; characterized in that: The centering device is detachably mounted on the cylinder head bolt and includes a lower ring assembly, an upper ring assembly, and several wedge-shaped positioning plates. The lower ring assembly is clamped around the cylinder head bolt below the cylinder head. The upper ring assembly is threaded onto the lower ring assembly and surrounds the outer periphery of the cylinder head bolt between the lower ring assembly and the cylinder head. The shape of the wedge-shaped positioning plates gradually narrows from bottom to top. Several wedge-shaped positioning plates are evenly positioned at the bottom and hinged to the periphery of the upper end of the upper ring assembly, and swing in the radial plane of the cylinder head bolt. The upper ring assembly is spirally lifted by rotating on the lower ring assembly, pushing the wedge-shaped positioning plates upward and simultaneously inserting their tops into the gap between the cylinder head bolt and the bolt hole of the cylinder head. As the wedge-shaped positioning plates are inserted deeper, the cylinder head bolt is gradually pressed and positioned to the center of the bolt hole. The lower ring assembly is formed by the mating of a right ring clamp and a left ring clamp. The upper outer circumference is provided with an external thread for connecting the upper ring assembly. The two sides of the lower outer circumference are respectively provided with a hinge assembly and a locking assembly. The right ring clamp and the left ring clamp rotate around the hinge assembly to open and close, and are locked by the locking assembly, thereby clamping the lower ring assembly immovably onto the cylinder head bolt. The upper ring assembly is formed by the mating of a right ring and a left ring. The lower inner wall is provided with an internal thread for connecting the lower ring assembly. The two sides of the outer periphery are respectively provided with a hinge assembly and a locking assembly. The right ring and the left ring rotate around the hinge assembly to open and close, and are locked by the locking assembly.

2. The centering device for pumping tightness of cylinder head bolts in marine main engines according to claim 1, characterized in that: The lower inner wall of the lower ring assembly is provided with a rubber layer for protection and to increase friction.

3. The centering device for pumping tightness of cylinder head bolts in marine main engines according to claim 1, characterized in that: The hinge assembly consists of a vertical round pin and a left pin seat and a right pin seat that pass through it, and the locking assembly consists of a horizontal bolt and two connecting lugs that connect it.

4. The centering device for pumping tightness of cylinder head bolts in marine main engines according to claim 1, characterized in that: The upper ring assembly has several evenly distributed hinge seats on its outer periphery for hinged to the wedge-shaped positioning frame plate.

5. The centering device for pumping tightness of cylinder head bolts in marine main engines according to claim 1, characterized in that: The wedge-shaped positioning bracket plate has a plate surface that is parallel to the radial plane of the cylinder head bolt along the axial direction of the cylinder head bolt and has an inclined wedge edge on the outer side. As the inclined wedge edge extends, the wedge-shaped positioning bracket plate gradually narrows from the bottom to the top.

6. A centering method for pump-tightening cylinder head bolts in marine main engines, characterized in that: Using the centering device for pumping tightness of cylinder head bolts for marine main engines as described in any one of claims 1-5, the operation steps of the centering method for pumping tightness of cylinder head bolts for marine main engines are as follows: The first step is to install the cylinder head by pre-installing the nuts on the cylinder head bolts without tightening them, and then inserting and locking the lower ring assembly at a suitable height position on the cylinder head bolts below the cylinder head. The second step is to fit the upper ring assembly onto the cylinder head bolt between the lower ring assembly and the cylinder head and lock it in place. Then, the upper ring assembly and the lower ring assembly are screwed together. The height of the centering device on the cylinder head bolt is adjusted to maintain a suitable distance from the cylinder head. The lower ring assembly is then locked and clamped to the cylinder head bolt, thereby completing the installation of the centering device on the cylinder head bolt. Third, swing all the wedge-shaped positioning plates upward and against the cylinder head bolts, rotate the upper ring assembly to slowly rise, so that the top of each wedge-shaped positioning plate is simultaneously inserted into the gap between the cylinder head bolt and the bolt hole of the cylinder head. As the wedge-shaped positioning plates continue to rise, the cylinder head bolt is gradually squeezed towards the center of the bolt hole of the cylinder head until the cylinder head bolt is accurately positioned in the center of the bolt hole.

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