Magnetic quick-change core-pulling oil injection device

Abstract

The utility model relates to a kind of quick-change formula core-pulling oil injection device of magnetic attraction, including shell, and magnet is equipped on the rear end surface of shell;Oil passage is equipped in shell, and core rod pull rod end portion is inserted in oil passage, shell side wall is equipped with the oil injection hole of intercommunication oil passage, and oil injection hole is connected with inlet tube;Junction plug is equipped with jack;Top plug includes sealing part and main part, and elastic member is supported between main part and oil passage bottom portion;Elastic member can be acted on main part to make sealing part extend into jack to form seal;Annular oil guide groove is formed between the outer side of core rod pull rod end portion and the inner wall inner end of jack, and it is equipped with the notch of intercommunication lubricating passage and oil guide groove on it.In the above scheme, when shell is quickly adsorbed on core-pulling device by magnet, the end of core rod pull rod will open top plug sealing part, and oil pipe and lubricating passage are conducted;When replacing core rod pull rod, shell is pulled down, and top plug will plug sealing part back into junction plug due to the elastic force of elastic member, realize the quick disassembly of core rod pull rod, and improve production efficiency.

Description

Technical Field

[0001] This utility model relates to the field of aerospace pipe bending machine technology, and in particular to a magnetic quick-change core-pulling and oil-injection device. Background Technology

[0002] Grease nipples, also known as grease guns, are one of the simplest methods of mechanical lubrication. They are categorized into straight-through grease nipples, connector-type grease nipples, and screw-cap grease nipples, used to connect grease guns to mechanical equipment. A Chinese utility model patent with publication number CN222849014U discloses an adjustable grease nipple, including a connecting tube and an input tube. The connecting tube is movably sleeved at one end of the input tube, and the two are connected. The input tube has a circumferentially rotatable adjusting cap connected to the connecting tube. The other end of the input tube has a one-way valve with a circumferentially rotatable locking assembly on its outer wall. The connecting tube and input tube are connected by a rotatable insert and sealed by the adjusting cap. Regardless of how the connecting tube is connected to the equipment, the input tube can be adjusted during installation to avoid obstruction and ensure convenient subsequent lubrication.

[0003] Aircraft, rockets, and spacecraft are equipped with numerous metal conduits designed to transport various fluids and support the equipment's flight missions; these conduits are crucial components of these devices. These metal conduits are manufactured using pipe bending machines. The lubrication channels inside the mandrel pull rod of the pipe bending machine need to be connected to external oil pipes via a straight-through pressure-filled oil cup. Because different specifications of mandrel pull rods need to be frequently replaced on the pipe bending machine, the straight-through pressure-filled oil cup between the oil pipe and the mandrel pull rod needs to be frequently disassembled and reassembled. This makes oil pipe disassembly not only cumbersome but also damages the oil pipe joints, affecting the efficiency of mandrel pull rod replacement, reducing production efficiency, shortening equipment lifespan, and increasing production costs. Summary of the Invention

[0004] To address the aforementioned problems, the purpose of this invention is to provide a magnetic quick-change core-pulling oil injection device. This device can be quickly removed from the core rod without disassembling the oil pipe, reducing damage to the joint. At the same time, it can also be quickly assembled when connecting the core rod, improving the efficiency of core rod replacement and thus increasing production efficiency.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A magnetic quick-change core-pulling and oil-filling device is characterized by: a housing, a mounting groove on the rear end face of the housing, a magnet for adsorbing onto the end face of the core-pulling device fixed in the mounting groove; an oil passage extending to the rear end face inside the housing, a core rod end protruding from the core-pulling device and insertable into the oil passage, the core rod having an axially penetrating lubrication channel inside; and an oil filling hole communicating with the oil passage on the side wall of the housing, with an oil inlet pipe connected to the oil filling hole. The oil passage is equipped with a connecting plug, a top plug, and an elastic element. The connecting plug is fixed to the oil passage outlet and has an insertion hole for the end of the mandrel pull rod to be inserted. The top plug includes a sealing part and a main body. The main body is adapted to abut against the oil passage, and the elastic element is supported between the main body and the bottom of the oil passage. An oil passage gap communicating with the oil injection hole is formed between the sealing part and the inner wall of the oil passage. The elastic element can act on the main body to make the sealing part extend into the insertion hole to form a seal. The outer side of the end of the mandrel pull rod forms a truncated cone shape with a gradually narrowing outer diameter, and an annular oil guide groove is formed between it and the inner end of the inner wall of the insertion hole. A cut is provided on it to connect the lubrication channel and the oil guide groove. When the housing is adsorbed on the end face of the core-pulling device, the end of the mandrel pull rod is inserted into the insertion hole and opens the sealing part, thereby guiding the oil passage gap, the oil guide groove, the cut, and the lubrication channel to be connected. When the housing is removed, the top plug is reset under the action of the elastic element to seal the insertion hole.

[0006] In the above technical solution, the oil pipe and the mandrel rod are connected by a housing. The rear end face of the housing is magnetically attached to the core-pulling device containing the mandrel rod. An oil passage is provided inside the housing to connect to the oil pipe. A connecting plug (or a threaded plug), a top plug, and an elastic element are fixedly installed inside the oil passage. An insertion hole is formed on the connecting plug. A cutout is provided on the outer side of the end of the mandrel rod, forming an annular oil guide groove between the cutout and the inner wall of the connecting plug. The front sealing part of the top plug can extend into the insertion hole to form a seal. An oil passage gap is formed between the sealing part and the oil passage. When the housing is quickly attached to the core-pulling device by a magnet, the end of the mandrel rod is quickly inserted into the oil passage of the oil injection device, pushing open the top plug sealing part in the insertion hole. Oil enters the lubrication channel after passing through the oil pipe, oil injection hole, oil passage gap, oil guide groove, and cut. When replacing the mandrel rod, the housing (oil injection device) is pulled out. Due to the elastic force of the elastic element, the top plug pushes the sealing part back into the connecting plug, blocking the insertion hole and preventing leakage. This achieves quick assembly and disassembly of the mandrel rod, improving production efficiency. This structure does not require disassembly of the oil pipe, reducing damage to the joint and extending the service life of the equipment.

[0007] Preferably, the rear end face of the housing is provided with an annular mounting groove, in which an annular magnet is fitted and fixed.

[0008] Preferably, the mandrel pull rod has two symmetrical cuts on the outer side of its end.

[0009] Preferably, the inner end of the inner wall of the insertion hole is configured as a first frustum with a larger outer diameter and a smaller inner diameter, and the middle part of the sealing part is provided with an annular sealing platform. The front part of the sealing platform forms a frustum with a gradually narrowing outer diameter, and its surface forms a second frustum that abuts and seals with the first frustum.

[0010] Preferably, the sealing part has an annular plug on the front side of the sealing platform that abuts against the insertion hole. The front end of the plug forms a truncated cone shape with a gradually narrowing outer diameter, and its surface forms a third truncated cone surface. A first annular groove is formed between the plug and the sealing platform, and a first sealing ring is provided on the first annular groove.

[0011] Preferably, the inner wall of the oil passage outlet is provided with a limiting step, and the inner side of the limiting step forms a first insertion section in the oil passage. The side wall of the connecting plug is provided with a third annular groove. The connecting plug is provided with an annular first plug on the front side of the third annular groove, which is either plugged or threaded into the first insertion section. The front side wall of the first plug is provided with a first guide cone surface in the circumferential direction. The connecting plug is provided with multiple annular blocks at axial intervals on the rear side of the third annular groove, which abut against the inner wall of the oil passage. The side wall of the blocks is provided with multiple circumferentially spaced cross-sections that are clearance fit with the inner wall of the oil passage.

[0012] Preferably, the device also includes a plug, wherein the oil passage is axially disposed through the housing, the front end of the plug is provided with a receiving groove, the elastic element is a spring, and the spring abuts against the receiving groove and the main body; the middle part of the plug is provided with a fourth annular groove; the inner wall of the oil passage is provided with a second insertion section, the front part of the plug is provided with an annular second plug block that is plugged or threaded into the second insertion section, and the front side wall of the second plug block is provided with a second guide cone surface circumferentially.

[0013] Preferably, a fifth annular groove is provided on the rear end of the housing inside the annular mounting groove, and a third sealing ring is provided in the fifth annular groove.

[0014] Preferably, the surface of the housing is knurled.

[0015] The present invention adopts the above technical solution and has the following technical effects: ① The oil pipe and the mandrel rod are connected by a housing. The rear end of the housing is magnetically attached to the core-pulling device containing the mandrel rod. An oil passage is provided inside the housing to connect to the oil pipe. A connecting plug (or threaded plug), a top plug, and a spring are fixedly installed inside the oil passage. An insertion hole is formed on the connecting plug. A cutout is provided on the outer side of the end of the mandrel rod, forming an annular oil guide groove between the cutout and the inner wall of the connecting plug. The front sealing part of the top plug can extend into the insertion hole to form a seal. An oil passage gap is formed between the sealing part and the oil passage. Thus, in the housing… When the mandrel is quickly attached to the core-pulling device by a magnet, the end of the mandrel pull rod is quickly inserted into the oil passage of the oil injection device, pushing open the top plug sealing part in the insertion hole. Oil then enters the lubrication channel through the oil pipe, oil injection hole, oil passage gap, oil guide groove, and cut. When replacing the mandrel pull rod, the housing (oil injection device) is pulled off. Due to the elasticity of the spring, the top plug pushes the sealing part back into the connecting plug, blocking the insertion hole and preventing leakage. This achieves quick assembly and disassembly of the mandrel pull rod, improving production efficiency. This structure does not require disassembly of the oil pipe, reducing damage to the joint and extending the service life of the equipment.

[0016] ② The first conical surface on the sealing part abuts against the second conical surface on the connecting plug, which achieves a better sealing and limiting effect. At the same time, the volume of the oil guide groove between the second conical surface and the mandrel pull rod increases, thereby increasing the oil delivery capacity.

[0017] ③ A first sealing ring is provided on the sealing part of the top plug, a second sealing ring is provided on its main body, and a third sealing ring is provided on the adsorption end face of the shell, which greatly improves the sealing effect of the oil injection device and prevents leakage.

[0018] ④ The oil passage is axially installed on the housing, and a plug and spring are installed on the outside to facilitate the installation and removal of the top plug inside the oil passage, which is very convenient.

[0019] ⑤ The surface of the oil injection device housing is knurled to increase friction, so that the oil injection device can be removed. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the magnetic quick-change core-pulling and oil-filling device being assembled on the core-pulling device.

[0021] Figure 2 This is a three-dimensional structural diagram of a magnetic quick-change core-pulling oil injection device.

[0022] Figure 3 This is a schematic diagram of the core-pulling device extending from the end of the core rod pull rod.

[0023] Figure 4 A schematic diagram of the cross-section of the magnetic quick-change core-pulling and oil-filling device adsorbed onto the core-pulling device and cooperating with the core rod pull rod.

[0024] Figure 5This is a cross-sectional schematic diagram of the internal structure of the magnetic quick-change core-pulling oil injection device after it has been removed from the core-pulling device.

[0025] Figure 6 This is a three-dimensional structural diagram of the mandrel pull rod end ejecting the push plug.

[0026] Figure 7 This is a three-dimensional structural diagram of a top plug sealing the connecting plug under the action of a spring.

[0027] Figure 8 This is a three-dimensional structural diagram of the connector plug.

[0028] Figure 9 This is a schematic diagram showing the arrangement of the first and second sealing rings on the top plug.

[0029] Figure 10 This is a three-dimensional structural diagram of the top plug.

[0030] Figure 11 This is a schematic diagram showing the arrangement of the mounting slots on the housing.

[0031] Figure 12 This is a schematic diagram of the three-dimensional structure of the shell.

[0032] Figure 13 This is a schematic diagram of the cross-sectional structure of the shell. Detailed Implementation

[0033] The embodiments of this utility model 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 elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0034] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more, unless otherwise expressly defined.

[0036] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0037] In this invention, unless otherwise explicitly 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 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 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.

[0038] like Figures 1-13 The magnetic quick-change core-pulling oil injection device shown includes a housing 1. The rear end face of the housing 1 is provided with a mounting groove 2, and a magnet 3 for adsorbing onto the end face of the core-pulling device 6 is fixed in the mounting groove 2. The housing 1 is provided with an oil passage 4 extending to the rear end face. The end of the core rod 5 extends out of the core-pulling device 6 and can be inserted into the oil passage 4. The core rod 5 is provided with an axially penetrating lubrication channel 7. The side wall of the housing 1 is provided with an oil injection hole 8 communicating with the oil passage 4, and an oil inlet pipe 9 is connected to the oil injection hole 8. The oil passage 4 is provided with a connecting plug 10, a top plug 11 and an elastic element; the connecting plug 10 is fixed to the outlet of the oil passage 4 and is provided with an insertion hole 12 for the end of the core rod 5 to be inserted; the top plug 11 includes a sealing part 13 and a main body 14, the main body 14 is adapted to abut against the inside of the oil passage 4, and the elastic element is supported between the main body 14 and the bottom of the oil passage 4; an oil passage gap 15 communicating with the oil injection hole 8 is formed between the sealing part 13 and the inner wall of the oil passage 4, and the elastic element can act on the main body 14 to make the sealing part 13 extend into the insertion hole 12 to form a seal; The outer side of the end of the mandrel pull rod 5 forms a truncated cone shape with a gradually narrowing outer diameter, and an annular oil guide groove 16 is formed between it and the inner end of the inner wall of the insertion hole 12. A cut 17 is provided on it to connect the lubrication channel 7 and the oil guide groove 16. When the housing 1 is adsorbed on the end face of the core pulling device 6, the end of the mandrel pull rod 5 is inserted into the insertion hole 12 and pushes open the sealing part 13, thereby guiding the oil gap 15, the oil guide groove 16, the cut 17 and the lubrication channel 7 to be connected. When the housing 1 is removed, the top plug 11 is reset under the action of the elastic element so that the sealing part 13 seals the insertion hole 12.

[0039] In the above technical solution, the oil pipe and the mandrel rod are connected by a housing. The rear end face of the housing is magnetically attached to the core-pulling device containing the mandrel rod. An oil passage is provided inside the housing to connect to the oil pipe. A connecting plug (or a threaded plug), a top plug, and an elastic element are fixedly installed inside the oil passage. An insertion hole is formed on the connecting plug. A cut is provided on the outer side of the end of the mandrel rod. An annular oil guide groove is formed between the cut and the inner wall of the connecting plug. The front sealing part of the top plug can extend into the insertion hole to form a seal. An oil passage gap is formed between the sealing part and the oil passage. Thus, in the housing... When the core is quickly attracted to the core-pulling device by a magnet, the end of the core rod is quickly inserted into the oil passage of the oil injection device 300, opening the top plug sealing part in the insertion hole. Oil enters the lubrication channel after passing through the oil pipe, oil injection hole, oil passage gap, oil guide groove, and cut. When replacing the core rod, the housing (oil injection device) is pulled out. Due to the elastic force of the elastic element, the top plug pushes the sealing part back into the connecting plug, blocking the insertion hole and preventing leakage. This achieves quick disassembly and assembly of the core rod, improving production efficiency. This structure does not require disassembly of the oil pipe, reducing damage to the joint and extending the service life of the equipment.

[0040] It should be noted that the oil injection pipe and the oil injection hole are connected by a connector 100, which makes assembly convenient.

[0041] like Figure 2 and Figure 11 As shown, an annular mounting groove 2 is provided on the rear end face of the housing 1, and an annular magnet 3 is adapted and fixed in it. In this technical solution, the cooperation between the annular magnet and the annular mounting groove provides a stable, uniform and strong adsorption force, ensuring that the device and the end face of the core-pulling device are tightly fitted. It should be noted that the magnet can be glued to the oil-filling device with AB glue to facilitate the fixation of the magnet and ensure that the end face of the magnet is flat and adsorbed.

[0042] like Figure 3 As shown, two symmetrical cuts 17 are provided on the outer side of the end of the mandrel pull rod 5. In this technical solution, the symmetrically arranged cuts allow the oil to flow more evenly and stably from the annular oil guide groove into the oil passage of the mandrel pull rod, avoiding uneven pressure or insufficient flow caused by unilateral oil supply, and improving the balance and reliability of oil injection.

[0043] like Figure 4 and Figure 7 As shown, the inner end of the inner wall of the insertion hole 12 is configured as a first frustoconical surface 18 with a larger outer diameter and a smaller inner diameter. The sealing part 13 has an annular sealing platform 19 in its middle. The front part of the sealing platform 19 forms a frustoconical shape with a gradually decreasing outer diameter, and its surface forms a second frustoconical surface 20 that abuts and seals against the first frustoconical surface 18. In this technical solution, the first frustoconical surface on the sealing part abuts and cooperates with the second frustoconical surface on the connecting plug, achieving a better sealing and limiting effect. Simultaneously, the volume of the oil guide groove between the second frustoconical surface and the mandrel pull rod increases, increasing the oil delivery capacity. The conical surface fit provides good guidance and low frictional resistance during the top plug's movement, facilitating smooth insertion and withdrawal of the sealing part and extending the sealing life.

[0044] like Figures 4-10 As shown, the sealing part 13 has an annular plug 21 on the front side of the sealing platform 19, which abuts against the insertion hole 12. The front end of the plug 21 forms a truncated cone shape with a gradually narrowing outer diameter, and its surface forms a third truncated cone surface 22. A first annular groove 23 is formed between the plug 21 and the sealing platform 19, and a first sealing ring 24 is provided on the first annular groove 23. In this technical solution, the annular plug forms the first sealing barrier at the front end, which together with the sealing platform (second truncated cone surface) at the rear constitutes a double seal, greatly improving the sealing reliability at the insertion hole inlet. If the sealing part is slightly smaller, the third truncated cone surface ensures that the sealing part moves forward and is guided into the insertion hole, playing a safety role. The first sealing ring further enhances the sealing effect and prevents oil from leaking from the mating gap between the top plug and the connecting plug after the housing is removed.

[0045] The side wall of the main body 14 is provided with a second annular groove 25 in the circumferential direction, and a second sealing ring 26 is provided on the second annular groove 25. In this technical solution, the second sealing ring ensures the static seal between the main body of the top plug and the inner wall of the oil passage, preventing high-pressure oil from leaking from the periphery of the top plug to the rear of the oil passage.

[0046] The inner wall of the outlet of the oil passage 4 is provided with a limiting step. The inner side of the limiting step forms a first insertion section 28 within the oil passage 4. The side wall of the connecting plug 10 is provided with a third annular groove 27. An annular first plug 30 is provided on the front side of the third annular groove 27 on the connecting plug 10, which is either tightly plugged or threaded into the first insertion section 28. The front side wall of the first plug 30 is provided with a first guide cone surface 31 circumferentially. Multiple annular blocks 32 are provided on the connecting plug 10 at axial intervals on the rear side of the third annular groove 27, which abut against the inner wall of the oil passage 4. The side wall of the blocks 32 is provided with multiple circumferentially spaced cut surfaces 33 that are clearance-fitted with the inner wall of the oil passage 4. In this technical solution, the front part of the connecting plug is tightly fitted into the first insertion section, and its front first guide cone surface plays a guiding role. The third annular groove reduces the contact area with the inner wall of the oil passage, which is conducive to disassembly and assembly. The connecting plug is inserted into the oil passage until the innermost block and the limiting step are engaged. The cut surface of the block is clearance-fitted with the inner wall of the oil passage, which is convenient for disassembly and assembly.

[0047] Furthermore, the oil injection device also includes a plug 34. The oil passage 4 is axially inserted into the housing 1. The front end of the plug 34 is provided with a receiving groove. The elastic element is a spring 35, which abuts against the receiving groove and the main body 14. The middle part of the plug 34 is provided with a fourth annular groove 36. The inner wall of the oil passage 4 is provided with a second insertion section 38. The front part of the plug 34 is provided with an annular second plug 39 that is tightly or threadedly connected to the second insertion section 38. The front side wall of the second plug 39 is provided with a second guide cone surface 40. In this technical solution, the oil passage is axially inserted into the housing, which facilitates the disassembly and assembly of the spring and the top plug. The front part of the plug is tightly fitted into the second insertion section, and its front second guide cone surface plays a guiding role. The fourth annular groove reduces the contact area with the inner wall of the oil passage, which is conducive to disassembly and assembly.

[0048] like Figure 2 and Figure 11 As shown, a fifth annular groove 41 is provided on the inner side of the annular mounting groove 2 at the rear end of the housing 1, and a third sealing ring 42 is provided in the fifth annular groove 41. In this technical solution, when the device is adsorbed onto the end face of the core-pulling device, it can effectively seal any possible microscopic uneven gaps, forming an auxiliary sealing ring, further preventing the possibility of oil leakage from the adsorption interface.

[0049] It should be noted here that, as Figure 3 As shown, the outer support rod end 200 of the mandrel pull rod protrudes from the end face of the core-pulling device. When the oil injection device cooperates with the mandrel pull rod, the support rod end 200 is exactly supported at the oil passage opening, which plays a certain supporting role and improves the stability of the oil injection device.

[0050] Furthermore, the surface of the housing 1 is provided with knurling 43. In this technical solution, the knurling on the surface of the housing increases friction, making it less likely for the operator to slip when holding the housing for installation, disassembly, or adjustment, thus improving the safety and convenience of operation.

[0051] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0052] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A magnetic quick-change core-pulling oil injection device, characterized in that: The device includes a housing (1), a mounting groove (2) on the rear end face of the housing (1), a magnet (3) for adsorbing onto the end face of the core-pulling device (6) is fixed in the mounting groove (2); an oil passage (4) extending to the rear end face is provided inside the housing (1), the end of the core rod (5) extends out of the core-pulling device (6) and can be inserted into the oil passage (4), and an axially penetrating lubrication channel (7) is provided inside the core rod (5); an oil injection hole (8) communicating with the oil passage (4) is provided on the side wall of the housing (1), and an oil inlet pipe (9) is connected to the oil injection hole (8); The oil passage (4) is provided with a connecting plug (10), a top plug (11), and an elastic element; the connecting plug (10) is fixed to the outlet of the oil passage (4) and is provided with an insertion hole (12) for the end of the core rod (5) to be inserted; the top plug (11) includes a sealing part (13) and a main body part (14), the main body part (14) is adapted to abut against the oil passage (4), and the elastic element is supported between the main body part (14) and the bottom of the oil passage (4); an oil passage gap (15) communicating with the oil injection hole (8) is formed between the sealing part (13) and the inner wall of the oil passage (4), and the elastic element can act on the main body part (14) to make the sealing part (13) extend into the insertion hole (12) to form a seal. The outer side of the end of the mandrel pull rod (5) forms a tapered cone shape with a gradually narrowing outer diameter, and an annular oil guide groove (16) is formed between the inner end of the inner wall of the insertion hole (12). A cut (17) is provided on it to connect the lubrication channel (7) and the oil guide groove (16). When the housing (1) is adsorbed on the end face of the core pulling device (6), the end of the mandrel pull rod (5) is inserted into the insertion hole (12) and pushes open the sealing part (13), thereby guiding the oil gap (15), the oil guide groove (16), the cut (17) and the lubrication channel (7) to be connected. When the housing (1) is removed, the top plug (11) is reset under the action of the elastic element so that the sealing part (13) seals the insertion hole (12).

2. The magnetic quick-change core-pulling oil injection device according to claim 1, characterized in that: The rear end face of the housing (1) is provided with an annular mounting groove (2), and an annular magnet (3) is adapted and fixed inside it.

3. The magnetic quick-change core-pulling oil injection device according to claim 1, characterized in that: The mandrel (5) has two symmetrical cuts (17) on the outer side of its end.

4. The magnetic quick-change core-pulling oil injection device according to claim 3, characterized in that: The inner end of the inner wall of the insertion hole (12) is set as a first frustum surface (18) with a larger outer diameter and a smaller inner diameter. The middle part of the sealing part (13) is provided with an annular sealing platform (19). The front part of the sealing platform (19) forms a frustum shape with a gradually narrowing outer diameter, and its surface forms a second frustum surface (20) that abuts and seals with the first frustum surface (18).

5. The magnetic quick-change core-pulling oil injection device according to claim 4, characterized in that: The sealing part (13) has an annular plug (21) on the front side of the sealing platform (19) that abuts against the insertion hole (12). The front end of the plug (21) forms a truncated cone shape with a gradually narrowing outer diameter, and its surface forms a third truncated cone surface (22). A first annular groove (23) is formed between the plug (21) and the sealing platform (19), and a first sealing ring (24) is provided on the first annular groove (23).

6. The magnetic quick-change core-pulling oil injection device according to claim 1, characterized in that: The side wall of the main body (14) is provided with a second annular groove (25) in the circumferential direction, and a second sealing ring (26) is provided on the second annular groove (25).

7. The magnetic quick-change core-pulling oil injection device according to claim 1, characterized in that: The inner wall of the outlet of the oil passage (4) is provided with a limiting step. The inner side of the limiting step forms a first insertion section (28) in the oil passage (4). The side wall of the connecting plug (10) is provided with a third annular groove (27). The connecting plug (10) is provided with an annular first plug (30) on the front side of the third annular groove (27) to be tightly or threaded into the first insertion section (28). The front side wall of the first plug (30) is provided with a first guide cone surface (31) in the circumferential direction. The connecting plug (10) is provided with multiple annular blocks (32) on the rear side of the third annular groove (27) at axial intervals, which abut against the inner wall of the oil passage (4). The side wall of the blocks (32) is provided with multiple cut surfaces (33) at circumferential intervals and clearance fits with the inner wall of the oil passage (4).

8. The magnetic quick-change core-pulling oil injection device according to claim 1, characterized in that: It also includes a plug (34), the oil passage (4) is axially disposed on the housing (1), the front end of the plug (34) is provided with a receiving groove, the elastic element is a spring (35), the spring (35) abuts between the receiving groove and the main body (14); the middle part of the plug (34) is provided with a fourth annular groove (36); the inner wall of the oil passage (4) is provided with a second insertion section (38), the front part of the plug (34) is provided with an annular second plug (39) to be plugged or threaded into the second insertion section (38), and the front side wall of the second plug (39) is provided with a second guide cone surface (40) circumferentially.

9. A magnetic quick-change core-pulling oil injection device according to claim 2, characterized in that: The rear end of the housing (1) is provided with a fifth annular groove (41) on the inner side of the annular mounting groove (2), and a third sealing ring (42) is provided in the fifth annular groove (41).

10. A magnetic quick-change core-pulling oil injection device according to claim 1, characterized in that: The surface of the housing (1) is provided with knurling (43).

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