Method for machining air inlet hole of gas valve hole of low-speed engine cylinder cover for dual-fuel ship

Abstract

According to the method for machining the air inlet holes of the fuel gas valve hole of the low-speed engine cylinder cover for the dual-fuel ship, the fuel gas valve hole comprises a main valve hole, a main air inlet hole and a parallel air inlet hole set, one end of the parallel air inlet hole set is communicated with the main valve hole, the other end of the parallel air inlet hole set is communicated with the main air inlet hole, and the included angle between the axis of the parallel air inlet hole set and the axis of the main valve hole is 58 degrees and the included angle between the parallel air inlet hole set and the orifice plane of the main valve hole is 32 degrees; the parallel air inlet hole set comprises a first air inlet connecting hole, a second air inlet connecting hole and a third air inlet connecting hole, the axes of the first air inlet connecting hole, the second air inlet connecting hole and the third air inlet connecting hole are parallel, the sections of the first air inlet connecting hole, the second air inlet connecting hole and the third air inlet connecting hole intersect, the sizes are the same, the diameter is 38 mm, the hole center distance is 21.5 mm, and the depth is larger than 350 mm. Step 4, mounting a filler rod, step 5, machining a first air inlet connecting hole and a third air inlet connecting hole in the two sides, and step 6, pulling out the filler rod. According to the method, high-efficiency and high-quality machining of the gas inlet hole of the gas valve hole of the low-speed engine cylinder cover for the dual-fuel ship is achieved, and the drawing requirement is met.

Description

Technical Field

[0001] The present invention relates to a processing technology for large-sized dual-fuel marine diesel engine parts, and particularly to a processing method for the air inlet holes of the gas valve holes on the cylinder head of a dual-fuel marine low-speed engine, belonging to the technical field of dual-fuel marine diesel engine processing. Background Art

[0002] The gas valve hole is a key part on the cylinder head of a dual-fuel marine diesel engine. Its traditional structure is shown in Figure 1 , the gas valve is installed in the gas valve hole of the cylinder head, and the intake of gas is connected to the gas valve through an outer pipe. The gas valve hole structure of this design is simple, and the processing is also very simple. It can be directly completed by using conventional drilling, boring, and milling cutters.

[0003] However, some large-sized dual-fuel marine diesel engine cylinder heads adopt a relatively special structure for the gas valve holes. Taking the main engine of the G95ME-C-LGIM model as an example, please refer to Figure 2 and Figure 3 , the gas valve hole of its cylinder head consists of a main valve hole D1, a main air inlet hole D2, and a parallel air inlet hole group D3; one end of the parallel air inlet hole group D3 is communicated with the main valve hole D1, and the other end is communicated with the main air inlet hole D2. The axis of the parallel air inlet hole group D3 forms an angle of 58° with the axis of the main valve hole D1 and an angle of 32° with the orifice plane of the main valve hole D1. The parallel air inlet hole group D3 is composed of three first air inlet connection holes D4, a second air inlet connection hole D5, and a third air inlet connection hole D6 with parallel axes and intersecting cross-sections; the first air inlet connection hole D4, the second air inlet connection hole D5, and the third air inlet connection hole D6 have the same size, with a diameter of 38 mm, a center distance of 21.5 mm between holes, and a depth > 350 mm.

[0004] Since the first air inlet connection hole D4, the second air inlet connection hole D5, and the third air inlet connection hole D6 are parallel in axis from beginning to end and have intersecting cross-sections, resulting in their cross-sections becoming incomplete circles with two adjacent breaks, there are serious tool deflection and tool knocking situations during the tool processing. In addition, due to the 32° angle between the parallel air inlet hole group D3 and the orifice plane of the main valve hole D1, it causes interference to the machine tool spindle, so the tool needs to be lengthened. As a result, the length-diameter ratio of the processing tool exceeds 10 times. Therefore, the processing of the gas valve holes of this special structure of dual-fuel marine diesel engine cylinder heads is much more difficult compared with the gas valve holes of the traditional structure. Especially in the parallel air inlet hole group D3 part, it makes it impossible to complete the processing using conventional drilling, boring, and milling processing methods. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a processing method for the intake holes of the gas valve holes on the cylinder head of a large dual-fuel marine diesel engine, aiming at the difficulty in machining the intake holes of the gas valve holes with a special structure on the cylinder head. By scientifically arranging the cutting sequence, setting up the tooling and reasonably using the cutting tools, a deep hole group with parallel axes and intersecting cross-sections that cannot be machined by conventional processing methods is completed, while meeting the processing requirements of the intake holes of the gas valve holes.

[0006] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0007] A processing method for the intake holes of the gas valve holes on the cylinder head of a dual-fuel marine low-speed engine. The gas valve holes are arranged on the cylinder head and include a main valve hole, a main intake hole and a parallel intake hole group. One end of the parallel intake hole group communicates with the main valve hole, and the other end communicates with the main intake hole. The axis of the parallel intake hole group forms an angle of 58° with the axis of the main valve hole and an angle of 32° with the orifice plane of the main valve hole. The parallel intake hole group includes a first intake connection hole, a second intake connection hole and a third intake connection hole with parallel axes and intersecting cross-sections. The second intake connection hole is located between the first intake connection hole and the third intake connection hole. The first intake connection hole, the second intake connection hole and the third intake connection hole have the same size, with a diameter of 38 mm, a hole center distance of 21.5 mm, and a depth > 350 mm. The characteristics of the processing method are as follows:

[0008] Step 1, machine the second intake connection hole

[0009] Taking the horizontal axis as the reference, turn the workpiece by 32°, use a milling cutter to machine a plane at the orifice of the second intake connection hole to create conditions for the subsequent centering of the drill bit, then use a short drill bit with a diameter of 38 mm to pre-drill a shallow hole, and finally use a gun drill with a diameter of 38 mm to complete the machining of the second intake connection hole;

[0010] Step 2, machine the side fixing screw holes

[0011] Taking the horizontal axis as the reference, turn the workpiece to -58°, and machine three side fixing screw holes on the cylinder head. The side fixing screw holes communicate with the second intake connection hole;

[0012] Step 3, machine the packing rod

[0013] Machine a cylindrical packing rod. Three counterbores are machined on the cylindrical surface of the packing rod, and two pull pin plate mounting screw holes along the axial direction of the packing rod are machined on the end face. The outer circle of the packing rod has a clearance fit with the second intake connection hole;

[0014] Step 4, install the packing rod

[0015] Insert the packing rod into the second air inlet connection hole, align the three counterbores with the three side fixing screw holes on the cylinder head respectively, tighten the side fixing screws in these side fixing screw holes, and let the heads enter the counterbores to fix the packing rod.

[0016] Step Five, machine the first air inlet connection hole and the third air inlet connection hole

[0017] Taking the horizontal axis as the reference, turn the workpiece by 32°, use a milling cutter to machine a plane at the orifice of the first air inlet connection hole and the third air inlet connection hole to create conditions for subsequent drill centering. Then, use a short drill with a diameter of 38 mm to pre-drill a shallow hole, and finally use a gun drill with a diameter of 38 mm to complete the machining of the first air inlet connection hole and the third air inlet connection hole.

[0018] Step Six, pull out the packing rod

[0019] Install the pin pulling plate through the pin pulling plate mounting screw holes on the end face of the packing rod, then connect the pin pulling device to this pin pulling plate, and pull out the packing rod outward to complete the machining of the air inlet holes of the gas valve holes.

[0020] Further, in the above Step Two, the side fixing screw holes are full-thread holes, and the axes are perpendicular to the axis of the second air inlet connection hole.

[0021] Further, in the above Step Three, the material of the packing rod is the same as that of the cylinder head body.

[0022] Further, in the above Step Six, the pin pulling plate is a disc-shaped component, which is provided with a connection hole for connecting the packing rod and a threaded hole for connecting the pin pulling device.

[0023] Compared with the traditional processing method, the present invention has achieved the following beneficial effects:

[0024] 1) The present invention takes the measure of inserting a packing rod into the already machined second air inlet connection hole in the middle, so that when machining the first air inlet connection hole and the third air inlet connection hole on both sides, the cutting tool cuts into the solid packing rod, and the working condition is the same as that of machining a solid part, avoiding the occurrence of tool deflection and tool knocking at the break part of the intersecting holes in the cross section. This not only reduces the damage of the cutting tool, but also ensures the machining quality of the air inlet holes.

[0025] 2) The present invention scientifically arranges the cutting processing sequence. First, the machining of the second air inlet connection hole in the middle is completed, creating conditions for machining the first air inlet connection hole and the third air inlet connection hole by combining the packing rod tooling.

[0026] In summary, the present invention solves the defect that the conventional processing method cannot machine parallel and intersecting deep holes in the cross section, realizes the high-efficiency and high-quality machining of the air inlet holes of the gas valve holes of the cylinder head of a dual-fuel marine low-speed engine, and meets the requirements of the drawings. Brief Description of the Drawings

[0027] Figure 1 is a schematic structural view of a traditional gas valve hole of a cylinder head of a large dual-fuel marine diesel engine.

[0028] Figure 2 is a schematic structural view of a special gas valve hole of a cylinder head of a dual-fuel marine diesel engine processed by the present invention.

[0029] Figure 3 is Figure 2 A - A sectional view of

[0030] Figure 4 is a schematic view of the second processing step of the present invention.

[0031] Figure 5 is a schematic view of the third processing step of the present invention.

[0032] Figure 6 is Figure 5 left view of

[0033] Figure 7 is a schematic view of the fourth processing step of the present invention.

[0034] Figure 8 is a schematic view of the fifth processing step of the present invention.

[0035] Figure 9 is Figure 8 E - E sectional view of

[0036] Figure 10 is Figure 9 F - direction view of

[0037] Figure 11 is a schematic view of the sixth processing step of the present invention.

[0038] Figure 12 is Figure 11 G - G sectional view of

[0039] Figure 13 is Figure 12 H - direction view of

[0040] In the figure,

[0041] D1 - main valve hole, D2 - main intake hole, D3 - parallel intake hole group, D4 - first intake connection hole, D5 - second intake connection hole, D6 - third intake connection hole, D7 - side fixing screw hole, D8 - counterbore, D9 - pull pin plate mounting screw hole, D10 - packing rod, D11 - side fixing screw, D12 - pull pin plate. Detailed Description of the Invention

[0042] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, but the protection scope of the present invention cannot be limited thereby.

[0043] The present invention is used for machining the intake holes of the gas valve holes on the cylinder head of a dual-fuel marine low-speed engine.

[0044] Embodiment

[0045] Taking the machining of the gas valve holes on the cylinder head of the G95-LGIM model main engine as an example, please refer to Figure 2 and Figure 3 , the gas valve hole is composed of a main valve hole D1, a main intake hole D2 and a parallel intake hole group D3; the parallel intake hole group D3 includes a first intake connection hole D4, a second intake connection hole D5 and a third intake connection hole D6. The axes of the first intake connection hole D4, the second intake connection hole D5 and the third intake connection hole D6 are parallel to each other, and the three holes are broken through, the cross-sections intersect, one end communicates with the main valve hole D1, and the other end communicates with the main intake hole D2. The axis of the parallel intake hole group D3 forms an angle of 58° with the axis of the main valve hole D1 and an angle of 32° with the orifice plane of the main valve hole D1. The first intake connection hole D4, the second intake connection hole D5 and the third intake connection hole D6 have the same size, with a diameter of 38 mm, a hole pitch of 21.5, are arranged in sequence, the depth > 350 mm, the surface roughness requirement is Ra12.5, and the diameter of the main valve hole D1 at the penetration with the parallel intake hole group D3 is 165 mm.

[0046] The specific machining process is as follows:

[0047] Step 1, machine the hole in the middle of the parallel intake hole group D3 - the second intake connection hole D5;

[0048] Taking the horizontal axis as the reference, turn the workpiece by 32°, and use a milling cutter to machine a plane at the orifice of the second intake connection hole D5 to create conditions for the subsequent centering of the drill bit; then use a short Φ38 drill bit to pre-drill a shallow hole, and then use a Φ38 gun drill to complete the machining of the second intake connection hole D5.

[0049] Step 2, machine the side fixing screw hole D7;

[0050] Please refer to Figure 4 , taking the horizontal axis as the reference, turn the workpiece to -58°, and machine three full-thread holes on the cylinder head, the side fixing screw hole D7, which is perpendicular and communicates with the second intake connection hole D5.

[0051] Step 3, machine the packing rod D10;

[0052] Please refer to Figure 5 and Figure 6, select a material similar to the cylinder head body and process it into a packing rod D10, which is in clearance fit with the second intake connection hole D5 on the cylinder head. Three counterbores D8 are machined on the cylinder of the packing rod D10, and two dowel plate mounting screw holes D9 are machined at the end face.

[0053] Step 4, install the packing rod D10;

[0054] Please refer to Figure 7 , insert the packing rod D10 into the second intake connection hole D5, align its counterbores D8 with the three side fixing screw holes D7 on the cylinder head, insert the side fixing screws D11, and tighten them.

[0055] Step 5, machine the holes on both sides of the parallel intake hole group D3, the first intake connection hole D4 and the third intake connection hole D6;

[0056] Please refer to Figure 8 、 Figure 9 and Figure 10 , with the horizontal axis as the reference, turn the workpiece by 32°, use a milling cutter to machine a plane at the orifice of the first intake connection hole D4 and the third intake connection hole D6 to create conditions for subsequent drill centering; then use a short Φ38 drill bit to pre-drill a shallow hole, and then use a Φ38 gun drill to complete the machining of the first intake connection hole D4 and the third intake connection hole D6.

[0057] Step 6, pull out the D10 plug rod

[0058] Please refer to Figure 11 、 Figure 12 and Figure 13 , through the two dowel plate mounting screw holes D9 on the end face of the packing rod D10, install the dowel plate D12, and then connect the threaded hole in the dowel plate D12 with a dowel puller to perform the operation of pulling out the packing rod D10.

[0059] The processing method of the intake holes of the gas valve holes of the double-fuel marine low-speed engine cylinder head described in the present invention solves the difficulty of machining deep holes with parallel intersections and large-scale breaks by conventional processing methods, avoids the situation of tool knocking and tool deflection caused by three consecutive side-by-side holes, and enables the machining of the intake holes of the gas valve holes to meet the drawing requirements.

[0060] The above is only the best embodiment of the present invention, but the protection scope required by the present invention is not limited to the above embodiments. Any obvious equivalent transformations and alternative solutions that can be obtained by those skilled in the art within the technical scope disclosed by the present invention without creative labor shall fall within the scope of the present invention.

Claims

1. A method for processing an air intake hole of a dual-fuel marine low-speed engine cylinder head gas valve hole, wherein the gas valve hole is arranged on the cylinder head, and comprises a main valve hole, a main air intake hole and a parallel air intake hole group, wherein one end of the parallel air intake hole group is connected with the main valve hole, and the other end is connected with the main air intake hole, the axis of the parallel air intake hole group is at an angle of 58° with the axis of the main valve hole, and is at an angle of 32° with the orifice plane of the main valve hole, the parallel air intake hole group comprises a first air intake connecting hole, a second air intake connecting hole and a third air intake connecting hole, the axes of which are parallel and whose cross sections intersect, the second air intake connecting hole is located between the first air intake connecting hole and the third air intake connecting hole, the first air intake connecting hole, the second air intake connecting hole and the third air intake connecting hole are of the same size, with a diameter of 38 mm, a hole center distance of 21.5 mm, and a depth of >350 mm; characterized in that: The processing method comprises the following steps: Step 1: Processing the second air inlet connection hole With the horizontal axis as the reference, the workpiece is turned 32 degrees, and a plane is machined at the opening of the second air intake connection hole with a milling tool to create conditions for subsequent drill centering, and then a short drill with a diameter of 38 mm is used to pre-drill a shallow hole, and then a gun drill with a diameter of 38 mm is used to complete the machining of the second air intake connection hole; Step 2: Processing the side screw holes With the horizontal axis as a reference, the workpiece is rotated to -58°, and three side fixing screw holes are processed on the cylinder head, wherein the side fixing screw holes are connected with the second air intake connecting hole; Step 3: Processing the filler rods Processing a cylindrical filler rod, wherein three countersunk holes are processed on the cylindrical surface of the filler rod, and two bolt holes for mounting a pin puller plate are processed on the end surface along the axial direction of the filler rod, and the outer circle of the filler rod is clearance-matched with the second air inlet connection hole; Step 4: Install the filler rod Insert the filler rod into the second air intake connection hole, align the three countersunk holes with the three side fixing screw holes on the cylinder head respectively, tighten the side fixing screws in the side fixing screw holes, push the heads into the countersunk holes, and fix the filler rod; Step 5: Processing the first air intake connection hole and the third air intake connection hole With the horizontal axis as the reference, the workpiece is turned 32°, and a plane is machined at the openings of the first air intake connection hole and the third air intake connection hole using a milling tool to create conditions for subsequent drill centering. A short drill with a diameter of 38 mm is then used to pre-drill a shallow hole, and then a gun drill with a diameter of 38 mm is used to complete the machining of the first air intake connection hole and the third air intake connection hole; Step 6: Pull out the filler rod The pin pulling plate is installed through the pin pulling plate installation screw hole on the end surface of the packing rod, and then the pin pulling plate is connected with a pin pulling device, and the packing rod is pulled outward to complete the processing of the gas valve hole air inlet hole.

2. The method for processing the air inlet hole of the gas valve hole of the cylinder head of a dual-fuel marine low-speed engine according to claim 1, characterized in that: In the step 2, the side fixing screw hole is a fully threaded hole, and the axis thereof is perpendicular to the axis of the second air inlet connecting hole.

3. The method for processing the air inlet hole of the gas valve hole of the cylinder head of a dual-fuel marine low-speed engine according to claim 1, characterized in that: In the step three, the material of the filler rod is the same as that of the cylinder head body.

4. The method for processing the air inlet hole of the gas valve hole of the cylinder head of a dual-fuel marine low-speed engine according to claim 1, characterized in that: In the step six, the pin pulling plate is a disc-shaped component, provided with a connecting hole for connecting the filler rod and a threaded hole for connecting the pin puller.

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