Quick forging machine main oil cylinder plunger replacing tool and replacing method thereof

Abstract

The invention relates to the technical field of rapid forging machine overhauling, in particular to a rapid forging machine main oil cylinder plunger replacing tool and a replacing method thereof. The rapid forging machine main oil cylinder plunger replacing tool comprises a hoop, an annular rubber pad, a supporting chuck and a steel wire rope, the outer ring of the annular rubber pad is attached to the inner ring of the hoop, the diameter of the inner ring of the annular rubber pad is matched with the diameter of a plunger on a rapid forging machine main oil cylinder, and a pair of traveling crane lifting points and a pair of chain block lifting points are arranged on the outer ring of the hoop. An accommodating space capable of accommodating a spherical body connecting part at the bottom of an upper plunger of a main oil cylinder of the fast forging machine is formed in the supporting chuck, and the hoop and the supporting chuck are connected into a whole through a steel wire rope. The tool for replacing the plunger of the main oil cylinder of the fast forging machine can prevent the plunger from falling off when the plunger is hoisted, and can protect the sealing surface on the outer side of the plunger.

Description

Technical Field

[0001] The invention relates to the technical field of high-speed forging machine maintenance, in particular to a tool for replacing a main oil cylinder plunger of a high-speed forging machine, and a method for replacing the main oil cylinder plunger of a high-speed forging machine using the tool. Background Art

[0002] Large-scale fast forging machine is a press equipment that changes the shape of steel by extruding the steel ingot, thereby realizing hot forging and forming of the steel ingot. The press equipment is mainly composed of three groups of upper, middle and lower beams and two side columns. Among them, the upper and lower beams and the two side columns are fixed structures, and the middle beam is a movable structure. Under the control of the return cylinders on both sides, the middle beam can move up and down along the two side columns. At the same time, three one-way main cylinder devices are installed between the middle beam and the upper beam, and the main cylinder devices can realize the downward forging of large bars.

[0003] Since the main oil cylinder equipment is operated under high oil pressure, high frequency and high temperature for a long time, the main oil cylinder plunger and other parts often deteriorate, so it is necessary to replace the main oil cylinder equipment parts regularly. However, there is not only no reliable lifting point on the plunger of the fast forging machine, but also it is located at the bottom of the upper beam, which makes it impossible to directly lift the main oil cylinder plunger by using the crane in the factory. In addition, the main oil cylinder plunger of the large fast forging machine has a diameter of 1040mm, a length of 3742mm and a weight of about 20t.

[0004] At present, the replacement process and replacement method of the main oil cylinder plunger are as follows: 1. Make the plunger fall into place as a whole with the middle beam, and the plunger is completely disengaged from the main oil cylinder shell; 2. Use a clamp to fix the plunger, and install a hand winch on the upper beam to connect the plunger; 3. Remove the connecting parts at the bottom of the plunger, and use a jacking equipment to lift the plunger to completely disengage the plunger from the middle beam; 4. Use the 20t hand winch on the upper beam to transport the plunger to the side of the upper beam; 5. After the plunger is moved to the outside of the upper beam as a whole, use the crane in the factory to lift the plunger. The reinstallation of the plunger can be carried out in the reverse order of the above specific removal steps.

[0005] Since the surface of the plunger is relatively smooth, the clamp is likely to slide relative to the plunger during the lifting process of the plunger, which may cause the plunger to fall during the lifting process; in addition, if the clamp is installed too tightly, it will also damage the outer sealing surface of the plunger, increasing the safety risk when the fast forging machine is running after the plunger is reinstalled. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a fast forging machine main cylinder plunger replacement tool that can prevent the plunger from falling during lifting and protect the outer sealing surface of the plunger.

[0007] The present invention adopts the following technical solution:

[0008] The invention provides a tool for replacing a plunger of a main oil cylinder of a fast forging machine, comprising a clamp, an annular rubber pad, a supporting chuck and a steel wire rope, wherein the outer ring of the annular rubber pad is fitted on the inner ring of the clamp, the inner ring diameter of the annular rubber pad matches the diameter of the plunger on the main oil cylinder of the fast forging machine, and a pair of crane hanging points and a pair of hand chain hoist hanging points are arranged on the outer ring of the clamp, an accommodating space for a spherical body connecting part of the bottom of the plunger on the main oil cylinder of the fast forging machine is provided on the supporting chuck, and the clamp and the supporting chuck are connected as a whole through a steel wire rope.

[0009] Preferably, the clamp includes a first half hoop and a second half hoop, the first half hoop and the second half hoop are detachably connected to form a complete annular clamp structure, and a crane lifting point and a hand winch lifting point are arranged at intervals on the first half hoop and the second half hoop, and the crane lifting point on the first half hoop and the hand winch lifting point on the second half hoop are all arranged opposite to each other at intervals.

[0010] Preferably, the supporting chuck comprises a first half-disc and a second half-disc, and the first half-disc and the second half-disc are detachably connected to form a complete disk-shaped structure.

[0011] Preferably, the top surface of the supporting chuck extends outward to form an annular wall, the diameter of the annular wall matches the diameter of the annular outer edge of the spherical body connection portion at the bottom of the plunger on the main cylinder of the fast forging machine, and a through hole penetrating the top surface is provided on the bottom surface of the supporting chuck, the diameter of the through hole is larger than the diameter of the spherical body at the bottom of the plunger on the main cylinder of the fast forging machine, the annular wall is coaxial with the through hole, and the diameter of the annular wall is larger than the diameter of the through hole.

[0012] Preferably, it also includes an inclined platform, two spaced support rods extending upward from the top surface of the inclined platform, each support rod having a concave notch on the top, and an even number of extension rods being arranged at equal intervals in a ring shape on the supporting chuck, each extension rod extending radially toward the outside of the supporting chuck, and any two extension rods spaced opposite to each other on the supporting chuck are respectively overlapped in the two concave notches of the inclined platform.

[0013] The present invention also provides a method for replacing a plunger of a main oil cylinder of a fast forging machine, which adopts the above-mentioned tool for replacing a plunger of a main oil cylinder of a fast forging machine and comprises the following steps:

[0014] S1: Move the plunger to be replaced downward along with the middle crossbeam as a whole, so that the plunger to be replaced is completely separated from the cylinder shell of the main oil cylinder, and remove the auxiliary parts around the plunger to be replaced;

[0015] S2: Install the supporting chuck on the bottom of the plunger to be replaced, so that the spherical connecting part of the bottom of the plunger to be replaced is accommodated in the accommodating space of the supporting chuck, and place the clamp on the plunger to be replaced, so that the inner ring of the annular rubber pad abuts against the outer sealing surface of the plunger to be replaced, and the supporting chuck and the clamp are connected as a whole by a steel wire rope;

[0016] S3: Install a hand chain hoist on both sides of the upper crossbeam, connect the two hand chain hoists to the two hand chain hoist lifting points on the clamp, and set two jacking devices at the bottom of the supporting chuck. Start the jacking devices and hand chain hoists synchronously to lift the plunger to be replaced;

[0017] S4: Manually tilt the plunger to be replaced so that it gradually moves outward from the bottom of the upper beam until the plunger to be replaced is removed from the bottom of the upper beam. Use the crane in the factory to connect the crane lifting point on the clamp to release the connection between the hand chain hoist and the clamp, and lift the plunger to be replaced away.

[0018] S5: Install the replacement tool for the main cylinder plunger of the fast forging machine onto the new plunger in the same manner as in step S2, connect the crane in the factory to the crane lifting point on the clamp, and lift the new plunger;

[0019] S6: Connect the two hand chain hoists to the two hand chain hoist points on the clamp respectively, release the connection between the crane and the clamp, and manually tilt the new plunger to gradually move the new plunger from the outside of the upper beam to the bottom until the new plunger is directly above the two jacking devices;

[0020] S7: Lower the new plunger back to the middle beam, remove the hand chain hoist and jacking equipment, reinstall the accessories, install the new plunger into the cylinder shell of the main cylinder, and move the new plunger upward with the middle beam as a whole.

[0021] Preferably, in step S2, the clamp is arranged above the center of gravity of the plunger to be replaced.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The fast forging machine main oil cylinder plunger replacement tool of the present invention is fixed to the plunger by a clamp when in use, and the presence of the annular rubber pad avoids the problem that the outer sealing surface of the plunger is squeezed out of the pit after the clamp is tightened, thereby protecting the outer sealing surface of the plunger; at the same time, the supporting chuck can support the plunger by accommodating the spherical connecting part at the bottom of the plunger in the accommodating space, thereby preventing the plunger from falling during the lifting process and improving the maintenance efficiency; after the clamp and the supporting chuck are connected as a whole by the wire rope, the clamp can realize the lifting and assembly and disassembly of the plunger through the crane lifting point and the hand winch lifting point.

[0024] The method for replacing the main cylinder plunger of a fast forging machine of the present invention naturally has the above-mentioned beneficial effects due to the use of the above-mentioned replacement tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is a schematic diagram of the use status of the tooling for replacing the main cylinder plunger of a fast forging machine in an embodiment of the present invention.

[0026] Figure 2 It is a schematic structural diagram of a clamp in a tool for replacing a main cylinder plunger of a fast forging machine in an embodiment of the present invention.

[0027] Figure 3 It is a structural schematic diagram of a supporting chuck in a tooling for replacing a main cylinder plunger of a fast forging machine in an embodiment of the present invention.

[0028] Figure 4 It is a structural schematic diagram of a tilting pedestal in a tool for replacing a main cylinder plunger of a fast forging machine in an embodiment of the present invention.

[0029] The reference numerals are described as follows:

[0030] 1. Clamp 24, annular wall

[0031] 11. Driving lifting point 25. Through hole

[0032] 12. Hand chain hoist lifting point 26. Extension rod

[0033] 13. First half hoop 3. Wire rope

[0034] 14. Second half hoop 4. Plunger

[0035] 2. Supporting chuck 5. Tilt stand

[0036] 21. Accommodation space 51. Support rod

[0037] 22. First half plate 52. Concave notch

[0038] 23. Second Half DETAILED DESCRIPTION

[0039] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. These embodiments are only used to illustrate the present invention, but not to limit the present invention.

[0040] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0041] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] Furthermore, in the description of the present invention, unless otherwise specified, “plurality” means two or more.

[0043] See also Figures 1 to 3 The present embodiment provides a tool for replacing the plunger of the main oil cylinder of a fast forging machine, comprising a clamp 1, an annular rubber pad, a supporting chuck 2 and a steel wire rope 3. The outer ring of the annular rubber pad fits on the inner ring of the clamp 1. The inner ring diameter of the annular rubber pad matches the diameter of the plunger 4 on the main oil cylinder of the fast forging machine. A pair of crane hanging points 11 and a pair of hand chain hoist hanging points 12 are provided on the outer ring of the clamp 1. The supporting chuck 2 is provided with an accommodating space 21 for accommodating the spherical connection part of the bottom of the plunger 4 on the main oil cylinder of the fast forging machine. The clamp 1 and the supporting chuck 2 are connected as a whole by a steel wire rope.

[0044] When in use, the fast forging machine main cylinder plunger replacement tool of this embodiment is fixed on the plunger 4 by the clamp 1, and the presence of the annular rubber pad avoids the problem that the outer sealing surface of the plunger 4 is squeezed out of the pit after the clamp 1 is tightened, thereby protecting the outer sealing surface of the plunger 4; at the same time, the supporting chuck 2 can support the plunger 4 by accommodating the spherical connecting part at the bottom of the plunger 4 in the accommodating space 21, thereby preventing the plunger 4 from falling during the lifting process and improving the maintenance efficiency; after the wire rope 3 connects the clamp 1 and the supporting chuck 2 as a whole, the clamp 1 can realize the lifting and assembly and disassembly of the plunger through the crane lifting point 11 and the hand winch lifting point 12.

[0045] Preferably, see Figure 2The clamp 1 includes a first half hoop 13 and a second half hoop 14, which are detachably connected to form a complete annular clamp structure, and a crane lifting point 11 and a hand chain hoist lifting point 12 are arranged on the first half hoop 13 and the second half hoop 14 at intervals, and the crane lifting point 11 on the first half hoop 13 and the crane lifting point 11 on the second half hoop 14, and the hand chain hoist lifting point 12 on the first half hoop 13 and the hand chain hoist lifting point 12 on the second half hoop 14 are arranged opposite to each other at intervals.

[0046] The clamp 1 is divided into a first half hoop 13 and a second half hoop 14, which can make the clamp 1 more convenient to install on the plunger 4. First, one half hoop is fitted on the plunger 4, and then the other half hoop is fitted on the plunger 4. Finally, the two half hoop are detachably connected to form a complete annular clamp structure, so that the connection between the clamp 1 and the plunger 4 can be achieved; and the crane lifting point 11 on the first half hoop 13 and the crane lifting point 11 on the second half hoop 14, the hand winch lifting point 12 on the first half hoop 13 and the hand winch lifting point 12 on the second half hoop 14 are all arranged relative to each other at intervals, which can ensure that after the hand winch and the crane in the factory are connected to the corresponding lifting point, the plunger 4 can be lifted in a vertical state, which is conducive to the deflection adjustment of the plunger 4.

[0047] Preferably, in this embodiment, the first half hoop 13 and the second half hoop 14 are reliably and detachably connected by bolts.

[0048] Preferably, see Figure 3 The supporting chuck 2 includes a first half-disc 22 and a second half-disc 23, and the first half-disc 22 and the second half-disc 23 are detachably connected to form a complete disc-shaped structure.

[0049] Since the plunger 4 is connected to the middle beam by installing the spherical body at the bottom into the installation groove of the middle beam, and there is a gap between the bottom of the plunger 4 and the middle beam, the supporting chuck 2 is divided into two half-disks, which makes the installation of the supporting chuck 2 on the plunger 4 more convenient. By connecting the two half-disks to the bottom of the plunger 4 in sequence from the gap position and then detachably connecting the two half-disks, the spherical body connecting part at the bottom of the plunger 4 can be accommodated in the accommodating space 21, thereby realizing the support of the plunger 4 by the supporting chuck 2.

[0050] Preferably, in this embodiment, the first half disk 22 and the second half disk 23 are detachably connected by bolts to form a complete disk-shaped structure.

[0051] Preferably, see Figure 3The top surface of the supporting chuck 2 extends outward to form an annular wall 24, the diameter of the annular wall 24 matches the diameter of the annular outer edge of the spherical body connection part at the bottom of the upper plunger 4 of the main oil cylinder of the fast forging machine, and a through hole 25 penetrating the top surface is opened on the bottom surface of the supporting chuck 2. The diameter of the through hole 25 is larger than the diameter of the spherical body at the bottom of the upper plunger 4 of the main oil cylinder of the fast forging machine. The annular wall 24 is coaxial with the through hole 25, and the diameter of the annular wall 24 is larger than the diameter of the through hole 25.

[0052] When the supporting chuck 2 supports the plunger 4, the spherical body at the bottom of the plunger 4 is located in the through hole 25, and the annular outer edge of the spherical body connection part is accommodated in the annular wall 24 and fits with the inner wall surface of the annular wall 24, thereby achieving stable support for the plunger 4 and preventing the plunger 4 from falling during the lifting process.

[0053] Preferably, see Figure 3 and Figure 4 The fast forging machine main cylinder plunger replacement tool of this embodiment also includes a tilting platform 5, and two spaced support rods 51 extend upward from the top surface of the tilting platform 5. A concave notch 52 is opened on the top of each support rod 51. An even number of extension rods 26 are arranged at equal intervals in a ring shape on the supporting chuck 2. Each extension rod 26 extends radially toward the outside of the supporting chuck 2. Any two extension rods 26 spaced opposite to each other on the supporting chuck 2 are respectively overlapped in the two concave notches 52 of the tilting platform 5.

[0054] After the plunger 4 is lifted vertically, the tilting seat 5 can be placed with its bottom surface downward on the middle beam, and any two extension rods 26 spaced opposite to each other on the supporting chuck 2 can be respectively overlapped in the two concave notches 52 of the tilting seat 5, so that the tilt adjustment of the plunger 4 can be achieved more labor-saving and conveniently with the support of the tilting seat 5, thereby improving the maintenance efficiency.

[0055] When it is necessary to replace the main cylinder plunger of a large-scale fast forging machine with a diameter of 1040mm, a length of 3742mm and a weight of about 20t, after the fast forging machine main cylinder plunger replacement tooling of this embodiment is adaptively adjusted, the load-bearing capacity of the tooling needs to reach 20t, the inner ring diameter of the clamp 1 after the annular rubber pad is installed is 1040mm, the thickness of the annular rubber pad is 6mm, and the specification of the hand winch used for lifting is 20t.

[0056] This embodiment also provides a method for replacing the plunger of the main oil cylinder of a high-speed forging machine, using the above-mentioned tooling for replacing the plunger of the main oil cylinder of the high-speed forging machine, combined with Figures 1 to 4 , and includes the following steps:

[0057] S1: Move the plunger 4 to be replaced downward along with the middle crossbeam as a whole, so that the plunger 4 to be replaced is completely separated from the cylinder shell of the main oil cylinder, and remove the auxiliary parts around the plunger 4 to be replaced;

[0058] S2: Install the supporting chuck 2 on the bottom of the plunger 4 to be replaced, so that the spherical connecting part of the bottom of the plunger 4 to be replaced is accommodated in the accommodating space 21 of the supporting chuck 2, and put the clamp 1 on the plunger 4 to be replaced, and make the inner ring of the annular rubber pad abut against the outer sealing surface of the plunger 4 to be replaced, and connect the supporting chuck 2 and the clamp 1 as a whole by the wire rope 3;

[0059] S3: Install a hand chain hoist on both sides of the upper crossbeam, respectively, and connect the two hand chain hoists to the two hand chain hoist lifting points 12 on the clamp 1, and set two jacking devices at the bottom of the supporting chuck 2, and start the jacking devices and hand chain hoists synchronously to lift the plunger 4 to be replaced;

[0060] S4: Manually tilt the plunger 4 to be replaced, so that the plunger 4 to be replaced gradually moves outward from the bottom of the upper beam until the plunger 4 to be replaced is moved out from the bottom of the upper beam, and use the crane in the factory to connect with the crane lifting point 11 on the clamp 1, release the connection between the hand chain hoist and the clamp 1, and lift the plunger 4 to be replaced;

[0061] S5: Install the replacement tool for the main cylinder plunger of the fast forging machine onto the new plunger 4 in the same manner as in step S2, connect the crane in the factory to the crane lifting point 11 on the clamp 1, and lift the new plunger 4;

[0062] S6: Connect the two hand chain hoists to the two hand chain hoist points 12 on the clamp 1 respectively, release the connection between the crane and the clamp 1, and manually tilt the new plunger 4 so that the new plunger 4 gradually moves from the outer side of the upper beam to the bottom until the new plunger 4 is located directly above the two jacking devices;

[0063] S7: Lower the new plunger 4 to the middle crossbeam, remove the hand chain hoist and the lifting equipment, reinstall the accessories, install the new plunger 4 into the cylinder shell of the main oil cylinder, and move the new plunger 4 upward as a whole with the middle crossbeam.

[0064] The method for replacing the main cylinder plunger of a fast forging machine can improve the safety of the lifting operation of the main cylinder plunger equipment, ensure that the outer sealing surface of the plunger 4 will not produce pits, scratches, etc. due to the lifting operation, and improve the maintenance quality of the plunger equipment.

[0065] It should be noted that the purpose of setting the jacking device is to move the spherical body at the bottom of the plunger 4 out of the installation groove of the middle beam; the hand chain hoist can ensure that the plunger 4 will not fall over during the process of jacking the plunger 4 by the jacking device.

[0066] Preferably, in step S2, the clamp 1 is disposed above the center of gravity of the plunger 4 to be replaced to prevent the plunger 4 from tipping over during the tilting process.

[0067] The above-mentioned fast forging machine main cylinder plunger replacement tooling and replacement method have been used in the 45MN fast forging machine main cylinder plunger replacement project of Daye Special Steel Forging Plant, which greatly improved the construction efficiency, improved maintenance safety, and improved construction efficiency, creating considerable economic benefits.

[0068] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A tool for replacing the plunger of the main oil cylinder of a fast forging machine, characterized in that: The invention comprises a clamp (1), an annular rubber pad, a supporting chuck (2) and a steel wire rope (3); the outer ring of the annular rubber pad fits on the inner ring of the clamp (1); the inner ring diameter of the annular rubber pad matches the diameter of the upper plunger (4) of the main oil cylinder of the fast forging machine; the outer ring of the clamp (1) is provided with a pair of crane lifting points (11) and a pair of hand chain hoist lifting points (12); the supporting chuck (2) is provided with a spherical body connection part capable of accommodating the bottom of the upper plunger (4) of the main oil cylinder of the fast forging machine; the clamp (1) and the supporting chuck (2) are connected as a whole through the steel wire rope (3).

2. The tooling for replacing the main cylinder plunger of a fast forging machine according to claim 1 is characterized in that: The clamp (1) comprises a first half clamp (13) and a second half clamp (14); the first half clamp (13) and the second half clamp (14) are detachably connected to form a complete annular clamp structure; and a crane lifting point (11) and a hand chain hoist lifting point (12) are arranged at intervals on the first half clamp (13) and the second half clamp (14); the crane lifting point (11) on the first half clamp (13) and the crane lifting point (11) on the second half clamp (14), and the hand chain hoist lifting point (12) on the first half clamp (13) and the hand chain hoist lifting point (12) on the second half clamp (14) are arranged at intervals and relative to each other.

3. The tooling for replacing the main cylinder plunger of a fast forging machine according to claim 1 is characterized in that: The supporting chuck (2) comprises a first half-disc (22) and a second half-disc (23), wherein the first half-disc (22) and the second half-disc (23) are detachably connected to form a complete disk-shaped structure.

4. The tooling for replacing the main cylinder plunger of a fast forging machine according to claim 1 is characterized in that: The top surface of the supporting chuck (2) extends outward to form an annular wall (24), the diameter of which matches the diameter of the annular outer edge of the spherical body connection portion at the bottom of the upper plunger (4) of the main oil cylinder of the fast forging machine. A through hole (25) penetrating the top surface is provided on the bottom surface of the supporting chuck (2), the diameter of the through hole (25) is larger than the diameter of the spherical body at the bottom of the upper plunger (4) of the main oil cylinder of the fast forging machine, the annular wall (24) is coaxial with the through hole (25), and the diameter of the annular wall (24) is larger than the diameter of the through hole (25).

5. The tooling for replacing the main cylinder plunger of a fast forging machine according to claim 1 is characterized in that: The invention also comprises an inclined platform (5), two spaced support rods (51) extending upward from the top surface of the inclined platform (5), each of the support rods (51) having a concave notch (52) formed on the top, and an even number of extension rods (26) being arranged at equal intervals in a ring shape on the supporting chuck (2), each of the extension rods (26) extending radially toward the outside of the supporting chuck (2), and any two spaced extension rods (26) on the supporting chuck (2) being respectively overlapped in the two concave notches (52) of the inclined platform (5).

6. A method for replacing the main cylinder plunger of a fast forging machine, characterized in that: The tool for replacing the main cylinder plunger of a fast forging machine according to any one of claims 1 to 5 is used, and comprises the following steps: S1: the plunger (4) to be replaced is moved downward along with the middle cross beam as a whole, so that the plunger (4) to be replaced is completely separated from the cylinder shell of the main oil cylinder, and the auxiliary parts around the plunger (4) to be replaced are removed; S2: The supporting chuck (2) is mounted on the bottom of the plunger (4) to be replaced, so that the spherical connecting portion of the bottom of the plunger (4) to be replaced is accommodated in the accommodation space (21) of the supporting chuck (2), the clamp (1) is clamped on the plunger (4) to be replaced, and the inner ring of the annular rubber pad is in contact with the outer sealing surface of the plunger (4) to be replaced, and the supporting chuck (2) and the clamp (1) are connected as a whole by the steel wire rope (3); S3: A hand chain hoist is installed on both sides of the upper crossbeam, and the two hand chain hoists are respectively connected to the two hand chain hoist lifting points (12) on the clamp (1), and two jacking devices are arranged at the bottom of the supporting chuck (2), and the jacking devices and the hand chain hoists are started synchronously to lift the plunger (4) to be replaced; S4: manually tilting the plunger (4) to be replaced so that the plunger (4) to be replaced gradually moves outward from the bottom of the upper beam until the plunger (4) to be replaced moves out from the bottom of the upper beam, connecting the crane in the factory with the crane lifting point (11) on the clamp (1), releasing the connection between the hand chain hoist and the clamp (1), and lifting the plunger (4) to be replaced; S5: Install the fast forging machine main cylinder plunger replacement tool on the new plunger (4) in the same manner as in step S2, connect the crane in the factory to the crane lifting point (11) on the clamp (1), and lift the new plunger (4); S6: Connect the two hand chain hoists to the two hand chain hoist points (12) on the clamp (1) respectively, release the connection between the crane and the clamp (1), and manually tilt the new plunger (4) so ​​that the new plunger (4) gradually moves from the outer side of the upper crossbeam to the bottom until the new plunger (4) is located directly above the two jacking devices; S7: Lower the new plunger (4) back onto the middle crossbeam, remove the hand chain hoist and the lifting device, reinstall the accessories, install the new plunger (4) into the cylinder shell of the main oil cylinder, and move the new plunger (4) upward as a whole with the middle crossbeam.

7. The method for replacing the main cylinder plunger of a rapid forging machine according to claim 6, characterized in that: In step S2, the clamp (1) is arranged at a position above the center of gravity of the plunger (4) to be replaced.

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