Pipe contracting machine for defrosting heater

Abstract

The utility model provides a pipe contracting machine for a defrosting heater, and belongs to the technical field of pipe contracting machines. Comprising a rack, a plurality of groups of rolling mechanisms and an oiling device, the oiling device comprises an oil absorption sponge and a fixing frame fixedly installed on the rack, an oil groove is formed in the fixing frame, the oil absorption sponge is located at the top end of the oil groove, the bottom end of the oil absorption sponge is provided with an oil absorption part extending into the oil groove, and the oil absorption sponge is provided with an oiling channel aligned to the rolling channel in the first rolling mechanism; the oil absorption sponge can continuously and uniformly smear the lubricating oil on the outer side wall of the pipe, and compared with oil dripping through an oil dripping pot, it can be guaranteed that all positions of the outer side wall of the pipe can be uniformly smeared with the lubricating oil, and the property consistency of all positions of the surface of the pipe after follow-up machining is improved; when a heating pipe of a defrosting heater is produced, the probability of surface defects can be reduced when a final defrosting heater finished product is under the working conditions that the temperature difference is large and the defrosting heater finished product is extruded by external frost, and the service life is prolonged.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of pipe reducing machines, and more particularly relates to a pipe reducing machine for a defrosting heater. BACKGROUND

[0002] Pipe reducing is a forming process of reducing the diameter of the end of a pipe blank. Cold reducing pipe is a pipe reducing method in which the diameter of a pipe material is continuously reduced to a target size through multiple rolling, and is one of main processing methods of an electric heating pipe. The main structure of the electric heating pipe includes a metal pipe and an electric heating wire in the metal pipe, and the metal pipe is filled with magnesium oxide powder and other materials with good insulation and heat conduction. The processing is carried out by a pipe reducing machine. One of the application scenarios of the electric heating pipe is to be used as a defrosting heater for use in refrigeration equipment such as a refrigerator to avoid failure of the refrigeration equipment due to excessive frosting.

[0003] In the prior art, a pipe reducing machine is disclosed in the utility model patent with publication number CN208131830U. In this scheme, the pipe material first passes through the oil dripping pot at the input end, the oil dripping pot continuously drips oil onto the pipe material to play a lubricating role, and then the pipe material continuously passes through the rolling mechanism. Since the width of the rolling groove in the rolling mechanism decreases in turn, the pipe diameter is continuously extruded and reduced to realize pipe reducing processing.

[0004] However, in this scheme, the oil dripped by the oil dripping pot is difficult to spread on the outer surface of the pipe material, and often flows linearly, with most of the surface not being coated with lubricating oil. Even if it is coated to a certain extent during movement, it is still difficult to completely adhere to the surface of the pipe material, resulting in inconsistent surface lubrication during pipe processing, and slight uniformity of the surface properties of the finished product after processing. For the defrosting heater, since its working environment is in a low temperature environment, ice and frost will be attached to the surface during work, and even be wrapped by ice, the internal and external temperature difference is large and the defrosting heater is extruded by the external ice, if the surface properties are not uniform, the defrosting heater is more likely to be damaged over time and the service life is reduced. SUMMARY

[0005] To solve the problems of the prior art, the application provides a pipe reducing machine for a defrosting heater, which can uniformly coat lubricating oil on the surface of the pipe material before pipe reducing, to improve the uniformity of the surface properties of the processed pipe material, ensure the use stability of the defrosting heater in a low temperature environment, and improve the service life.

[0006] To achieve the above object, the technical scheme of the present application provides a pipe shrinking machine for defrosting heater, which comprises a rack and a plurality of groups of roller pressing mechanisms, the roller pressing mechanisms are sequentially arranged along the rack, each group of roller pressing mechanisms has two roller pressing wheels arranged side by side and driven by a driving motor, the driving motor is fixedly installed on the rack, the two roller pressing wheels are in driving connection with the driving motor, each roller pressing wheel has a roller pressing groove, the roller pressing grooves of the two roller pressing wheels in each group of roller pressing mechanisms are opposite to each other and enclose a roller pressing channel, the widths of the roller pressing grooves in the plurality of groups of roller pressing mechanisms gradually decrease in sequence along the process direction; the rack is further provided with an oiling device located at the inlet end of the first roller pressing mechanism; the oiling device comprises an oil absorption sponge and a fixing frame fixedly installed on the rack, the fixing frame has an oil groove therein, the oil absorption sponge is located at the top end of the oil groove, the bottom end of the oil absorption sponge has an oil absorption part extending into the oil groove, and the oil absorption sponge is provided with an oiling channel aligned with the roller pressing channel in the first roller pressing mechanism.

[0007] The pipe passes through the oiling channel and then enters the roller pressing channel for processing. The oil absorption sponge can uniformly apply lubricating oil to the outer sidewall of the pipe without interruption, which can ensure that the lubricating oil is uniformly applied to all parts of the outer sidewall of the pipe without dead angles, and the properties of the pipe surface after subsequent processing are consistent. The oil absorption sponge can continuously absorb oil from the oil groove through the oil absorption part, ensuring that the oil level in the oil absorption sponge remains the same. For the production of heating pipes for defrosting heaters, it can ensure that the final defrosting heater product can reduce the probability of surface defects under the condition of large temperature difference and external frost extrusion, and prolong the service life.

[0008] Optionally, the oiling device further comprises a fixing plate and a fastening nut; the fixing frame has a fixing cavity located at the top end of the oil groove, the bottom wall of the fixing cavity has a communication port in communication with the oil groove, the oil absorption sponge is placed in the fixing cavity, and the oil absorption part extends into the oil groove through the communication port; two fixing grooves are symmetrically formed on the two sides of the oil absorption sponge, a fixing plate is inserted into each of the two fixing grooves, the fixing plate is provided with a screw rod, the end portion of the screw rod extends to the outside of the fixing frame through the oil absorption sponge and the side wall of the fixing cavity, and the portion of the screw rod extending to the outside of the fixing frame is screwed with the fastening nut. The position of the oil absorption sponge can be fixed firmly by the two fixing plates, the screw rod and the fastening nut, thereby ensuring the stability of the oil absorption sponge.

[0009] Optionally, the portion of the oil absorption sponge between the fixing plate and the side wall of the fixing cavity has a protruding part extending to the side, and the protruding part is clamped between the fixing plate and the side wall of the fixing cavity under pressure, so as to avoid the shaking of the fixing plate and the shifting of the position of the oiling channel.

[0010] Optionally, the rack is further provided with a guide pipe, one end of the guide pipe is aligned with the oiling channel, and the other end of the guide pipe is aligned with the rolling channel in the first rolling mechanism; the inner diameter of the guide pipe gradually decreases in the direction away from the oiling channel. Since the side wall of the oiling channel can be deformed, the pipe material can be slightly displaced laterally, and the end of the guide pipe with a larger inner diameter can ensure that the pipe material smoothly enters the inside of the guide pipe and gradually aligns to the rolling channel as the inner diameter of the guide pipe decreases, avoiding the situation that the pipe material cannot be aligned with the rolling channel.

[0011] Optionally, the side wall of the oil groove is provided with an oil injection hole, and the oil groove can be supplemented with lubricating oil by means of a main oil pump, manual addition or a communicating vessel, so as to avoid depletion of the lubricating oil.

[0012] Optionally, the rack has a first top plate and a second top plate arranged in a V shape, and the plurality of rolling mechanisms are divided into two groups and alternately installed on the first top plate and the second top plate. The rolling mechanisms on the first top plate and the second top plate can respectively extrude the pipe material in different spatial directions, ensuring the uniformity of the cross-sectional shape of the pipe material. The first top plate and the second top plate can be preferably perpendicular to each other, and the pipe material is extruded in two perpendicular directions, and the stress is uniform.

[0013] Optionally, the oil discharge hole is distributed along the extension direction of the junction of the first top plate and the second top plate, and the bottom end of the oil discharge hole is vertically provided with an oil guide needle, and the rack is provided with an oil collection box located at the bottom of all the oil guide needles. When the pipe material passes through the rolling mechanism, the lubricating oil dripping can fall into the oil collection box through the oil discharge hole and the oil guide needle. The oil guide needle has a drainage effect, and the lubricating oil can flow down along the outer side wall of the oil guide needle, avoiding deviation of the lubricating oil along the rack. The setting of the oil guide needle can also reduce the height of the liquid surface inside the oil collection box when the lubricating oil drips, avoiding splashing. At the same time, compared with the setting of the drainage pipe, the oil guide needle does not have the problem of blockage inside the pipeline.

[0014] Optionally, the inside of the rack is provided with a bearing groove located at the bottom of the oil discharge hole, and the side wall of the rack is provided with a socket aligned with the end of the bearing groove, and the oil collection box is inserted into the bearing groove from the socket. When the oil collection box is full of lubricating oil, the oil collection box can be taken out from the socket for cleaning. In actual use, since the lubricating oil is uniformly laid on the surface of the pipe material, the dripping amount is relatively small, and there is no need to set up a lubricating oil return device. The dripping amount of the lubricating oil used for a long time is also limited, and the cleaning period of the oil collection box is also long, and it does not need to be cleaned frequently.

[0015] Optionally, the rolling mechanism further comprises a coupling, a first gear, a second gear, a first rotating shaft, a second rotating shaft, a first adjusting part and a second adjusting part; the first rotating shaft is connected with the output end of the driving motor through the coupling, the second rotating shaft is arranged in parallel with the first rotating shaft, the first gear is fixedly sleeved on the outer side of the first rotating shaft, the second gear is fixedly sleeved on the outer side of the second rotating shaft, and the first gear and the second gear are engaged with each other; the two rolling wheels are respectively fixedly sleeved on the outer sides of the first rotating shaft and the second rotating shaft, the driving motor is fixedly connected with the rack, and the first adjusting part and the second adjusting part are respectively located on the two sides of the two rolling wheels and are arranged on the outer sides of the first rotating shaft and the second rotating shaft. The driving motor drives the first rotating shaft and the second rotating shaft to rotate to realize the relative rotation of the two rolling wheels. The first adjusting part and the second adjusting part are used for adjusting the distance between the first rotating shaft and the second rotating shaft to change the pipe reducing size.

[0016] The technical scheme of the present application has the beneficial effects over the prior art, which are as follows:

[0017] The oil absorption sponge can continuously and uniformly apply lubricating oil to the outer sidewall of the pipe, and can ensure that the lubricating oil is uniformly applied to all parts of the outer sidewall of the pipe without dead angles, thereby ensuring the consistency of the properties of the pipe surface after subsequent processing. The oil absorption sponge can continuously absorb oil from the oil tank through the oil absorption part to ensure that the oil level in the oil absorption sponge remains the same. When producing a heating pipe for a defrosting heater, the oil absorption sponge can ensure that the final defrosting heater product can reduce the probability of surface defects under the condition of a large temperature difference and external ice and snow extrusion, thereby prolonging the service life. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical scheme in the embodiments of the present application, the drawings needed in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0019] Figure 1 Fig. 1 is a schematic diagram of the overall structure of the pipe reducing machine for the defrosting heater;

[0020] Figure 2 Fig. 2 is a schematic diagram of the structure of the pipe reducing machine for the defrosting heater after the internal structure of the oil application device is cut open;

[0021] Figure 3 Fig. 3 is a schematic diagram of the structure of the pipe reducing machine for the defrosting heater after the internal structure of the oil application device is cut open; Figure 2 Fig. 4 is an enlarged view of part A in Fig. 3;

[0022] Figure 4 Fig. 5 is a schematic diagram of the structure of the rolling mechanism;

[0023] Figure 5Schematic view of oil absorption sponge structure;

[0024] Figure 6 Schematic view of guide pipe structure;

[0025] Figure 7 Schematic view of oil discharge hole and oil guide needle structure;

[0026] Figure 8 Schematic view of socket and oil collection box structure.

[0027] Icon: 1, rack; 101, guide pipe; 102, first top plate; 103, second top plate; 104, oil discharge hole; 105, oil guide needle; 106, oil collection box; 107, bearing groove; 108, socket; 2, roller mechanism; 201, roller; 202, roller groove; 203, roller channel; 204, drive motor; 205, coupling; 206, first gear; 207, second gear; 208, first rotating shaft; 209, second rotating shaft; 210, first adjusting part; 211, second adjusting part; 3, oiling device; 301, oil absorption sponge; 302, fixing frame; 303, oil groove; 304, oil absorption part; 305, oiling channel; 306, fixed plate; 307, fastening nut; 308, fixed cavity; 309, communication port; 310, fixed groove; 311, screw rod; 312, oil injection hole; 313, protruding part. DETAILED DESCRIPTION

[0028] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0029] Embodiment:

[0030] The embodiment provides a pipe shrinking machine for a defrosting heater, based on Figures 1 to 4As shown, it comprises a rack 1 and several groups of rolling mechanisms 2, and the rolling mechanisms 2 are arranged in sequence along the rack 1. Each group of rolling mechanisms 2 has a driving motor 204 and two parallel arranged rolling wheels 201, the driving motor 204 is fixedly installed on the rack 1, and the two rolling wheels 201 are in driving connection with the driving motor 204. Each rolling wheel 201 has a rolling groove 202, and the rolling grooves 202 of the two rolling wheels 201 in each group of rolling mechanisms 2 are opposite to each other and enclose a rolling channel 203. The widths of the rolling grooves 202 in the several groups of rolling mechanisms 2 decrease in sequence along the process direction. The pipe material passes through the rolling channels 203 of the several groups of rolling mechanisms 2 in sequence, and is driven by the rolling wheels 201 to pass through the rolling channels 203 formed by the rolling grooves 202 with decreasing widths in sequence, so as to realize pipe shrinking processing. On the basis of the above structure, the rack 1 is further provided with an oiling device 3 located at the inlet end of the first rolling mechanism 2. The oiling device 3 comprises an oil absorbing sponge 301 and a fixed frame 302 fixedly installed on the rack 1. The fixed frame 302 has an oil groove 303 therein, the oil absorbing sponge 301 is located at the top end of the oil groove 303, the bottom end of the oil absorbing sponge 301 has an oil absorbing part 304 extending into the oil groove 303, and the oil absorbing sponge 301 is provided with an oiling channel 305 aligned with the rolling channel 203 in the first rolling mechanism 2. The oil groove 303 is used for containing lubricating oil.

[0031] In use, the pipe material passes through the oiling channel 305 and then enters the rolling channel 203 for processing. The oil absorbing sponge 301 can continuously absorb oil from the oil groove 303 through the oil absorbing part 304, so as to ensure that the oil amount in the oil absorbing sponge 301 always remains at the same level. The oil absorbing sponge 301 can continuously and uniformly apply lubricating oil on the outer sidewall of the pipe material. Compared with dripping oil through an oil dropper, the oil absorbing sponge 301 can ensure that the lubricating oil is uniformly applied on the outer sidewall of the pipe material, and there is no dead angle, so as to ensure that the properties of the pipe material surface after subsequent processing are consistent. For the production of heating pipes of defrosting heaters, the higher consistency of the surface can ensure that the final defrosting heater product can reduce the probability of surface defects under the working condition of large temperature difference and external ice and snow extrusion, and prolong the service life.

[0032] Further, based on Figure 3As shown, the oiling device 3 further comprises a fixing plate 306 and a fastening nut 307. The fixing frame 302 has a fixing cavity 308 at the top end of the oil groove 303, the bottom wall of the fixing cavity 308 has a communication port 309 communicating with the oil groove 303, the oil absorption sponge 301 is placed in the fixing cavity 308, and the oil absorption part 304 extends into the oil groove 303 through the communication port 309. Specifically, two fixing grooves 310 are symmetrically formed on the two sides of the oil absorption sponge 301, and the fixing plate 306 is inserted into each of the two fixing grooves 310. The fixing plate 306 is provided with a threaded rod 311, the end of the threaded rod 311 extends to the outside of the fixing frame 302 through the side wall of the fixing cavity 308 and the oil absorption sponge 301, and the portion of the threaded rod 311 extending to the outside of the fixing frame 302 is screwed with the fastening nut 307. Through the two fixing plates 306, the threaded rod 311 and the fastening nut 307, the position of the oil absorption sponge 301 can be fixed firmly.

[0033] Preferably, based on Figure 3 and Figure 5 As shown, in order to ensure the stability of the connection, the portion of the oil absorption sponge 301 between the fixing plate 306 and the side wall of the fixing cavity 308 has a protruding part 313 extending to the side, and the protruding part 313 is clamped between the fixing plate 306 and the side wall of the fixing cavity 308 by compression. After the oil absorption sponge 301 is fixed in the fixing cavity 308, the protruding part 313 is fully extruded and cannot be deformed under force, which ensures that the position of the fixing plate 306 cannot shake and avoids the position of the oiling channel 305 from shifting. At the same time, this arrangement can also reduce the oil absorption capacity of the portion of the oil absorption sponge 301 between the fixing plate 306 and the side wall of the fixing cavity 308, so that the lubricating oil can more fully enter the side wall of the oiling channel 305.

[0034] Further, based on Figure 6 As shown, the rack 1 is further provided with a guide pipe 101, one end of the guide pipe 101 is aligned with the oiling channel 305, and the other end of the guide pipe 101 is aligned with the roller pressing channel 203 in the first roller pressing mechanism 2. The inner diameter of the guide pipe 101 gradually decreases in the direction away from the oiling channel 305. Since the side wall of the oiling channel 305 can be deformed, which may cause slight lateral displacement of the pipe material, the end of the guide pipe 101 with a larger inner diameter can ensure that the pipe material smoothly enters the inside of the guide pipe 101 and gradually aligns to the roller pressing channel 203 along with the decrease of the inner diameter of the guide pipe 101, avoiding the situation that the pipe material cannot align with the roller pressing channel 203.

[0035] Further, based on Figure 3 As shown, the side wall of the oil groove 303 is provided with an oil injection hole 312, and the lubricating oil can be supplemented into the oil groove 303 through a main oil pump, manual addition or a communicating vessel, avoiding the depletion of the lubricating oil.

[0036] Further, based on Figure 1 As shown andFigure 7 As shown, the rack 1 has a first top plate 102 and a second top plate 103 arranged in a V shape, and a plurality of rolling mechanisms 2 are alternately installed on the first top plate 102 and the second top plate 103. The rolling mechanisms 2 on the first top plate 102 and the second top plate 103 can respectively extrude the pipe in different spatial directions, ensuring the uniformity of the pipe cross-sectional shape. The first top plate 102 and the second top plate 103 can be preferably perpendicular to each other, and the pipe is extruded in two perpendicular directions, and the stress is uniform.

[0037] Further, based on Figure 7 As shown, the oil discharge holes 104 are distributed along the extension direction of the junction of the first top plate 102 and the second top plate 103, and the bottom end of the oil discharge hole 104 is vertically provided with an oil guide needle 105, and the rack 1 is provided with an oil collecting box 106 located at the bottom of all the oil guide needles 105. When the pipe passes through the rolling mechanism 2, the lubricating oil dripping can fall into the oil collecting box 106 through the oil discharge hole 104 and the oil guide needle 105 for collection. The oil guide needle 105 has a drainage effect, and the lubricating oil can flow down along the outer side wall of the oil guide needle 105, avoiding the deviation of the lubricating oil along the rack 1. The setting of the oil guide needle 105 can also reduce the height of the liquid surface inside the oil collecting box 106 when the lubricating oil drips, avoiding splashing. At the same time, compared with the setting of the drainage pipe, the oil guide needle 105 does not have the problem of internal blockage of the pipeline, ensuring the smooth discharge of oil.

[0038] At the same time, based on Figure 7 and Figure 8 As shown, the inside of the rack 1 is provided with a bearing groove 107 located at the bottom of the oil discharge hole 104, and the side wall of the rack 1 is provided with a socket 108 aligned with the end of the bearing groove 107, and the oil collecting box 106 is inserted into the bearing groove 107 from the socket 108. When the oil collecting box 106 is full of lubricating oil, the oil collecting box 106 can be taken out from the socket 108 for cleaning. In actual use, since the lubricating oil is uniformly laid on the pipe surface, the dripping amount is relatively small, and it is not necessary to set up a lubricating oil return device. The dripping amount of the lubricating oil used for a long time is also limited, and the cleaning period of the oil collecting box 106 is also relatively long, and it is not necessary to clean frequently.

[0039] In this embodiment, based on Figure 1 and Figure 4As shown, the rolling mechanism 2 further comprises a coupling 205, a first gear 206, a second gear 207, a first rotating shaft 208, a second rotating shaft 209, a first adjusting part 210 and a second adjusting part 211. The first rotating shaft 208 is connected with the output end of the driving motor 204 through the coupling 205, and the second rotating shaft 209 is arranged in parallel with the first rotating shaft 208. The first gear 206 is fixedly sleeved on the outer side of the first rotating shaft 208, the second gear 207 is fixedly sleeved on the outer side of the second rotating shaft 209, and the first gear 206 and the second gear 207 are engaged with each other. The two rolling wheels 201 are respectively fixedly sleeved on the outer sides of the first rotating shaft 208 and the second rotating shaft 209. The driving motor 204 drives the first rotating shaft 208 and the second rotating shaft 209 to rotate to realize the relative rotation of the two rolling wheels 201. The first adjusting part 210 and the second adjusting part 211 are respectively located on the two sides of the two rolling wheels 201 and are arranged on the outer sides of the first rotating shaft 208 and the second rotating shaft 209. The first adjusting part 210 and the second adjusting part 211 are used to adjust the distance between the first rotating shaft 208 and the second rotating shaft 209, so as to change the pipe shrinking size. The specific structure and principle of the first adjusting part 210 and the second adjusting part 211 are the same as those of the first adjusting part 210 and the second adjusting part 211 in the utility model patent with the publication number CN208131830U and the name of a pipe shrinking machine in the prior art, and will not be described in detail.

[0040] The oil-absorbing sponge 301 can continuously and uniformly apply lubricating oil to the outer side wall of the pipe material without interruption, which can ensure that the lubricating oil is uniformly applied to all parts of the outer side wall of the pipe material, and there is no dead angle, ensuring the consistency of the properties of the pipe material surface after subsequent processing. The oil-absorbing sponge 301 can continuously absorb oil from the oil tank 303 through the oil-absorbing part 304, ensuring that the oil amount in the oil-absorbing sponge 301 remains the same. When producing heating pipes for defrosting heaters, the oil-absorbing sponge 301 can ensure that the final defrosting heater product can reduce the probability of surface defects under the condition of large temperature difference and external frost extrusion, prolonging the service life.

[0041] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A defrosting heater pipe shrinking machine, comprising a frame and a plurality of groups of roller pressing mechanisms, the roller pressing mechanisms being sequentially arranged along the frame, each group of roller pressing mechanisms having two parallel roller pressing wheels driven by a driving motor fixedly installed on the frame, the roller pressing wheels being in driving connection with the driving motor, each roller pressing wheel having a roller pressing groove, the roller pressing grooves of the two roller pressing wheels in each group of roller pressing mechanisms being opposite to each other and surrounding a roller pressing channel, the widths of the roller pressing grooves in the plurality of groups of roller pressing mechanisms gradually decreasing along a process direction; characterized in that the frame is further provided with an oiling device located at an entrance end of a first roller pressing mechanism; the oiling device comprises an oil absorption sponge and a fixed frame fixedly installed on the frame, the fixed frame having an oil groove therein, the oil absorption sponge being located at a top end of the oil groove, a bottom end of the oil absorption sponge having an oil absorption portion extending into the oil groove, the oil absorption sponge being provided with an oiling channel aligned with the roller pressing channel in the first roller pressing mechanism.

2. The defrosting heater pipe shrinking machine according to claim 1, wherein: the oiling device further comprises a fixed plate and a fastening nut; the fixed frame has a fixed cavity located at a top end of the oil groove, a bottom wall of the fixed cavity having a communication port in communication with the oil groove, the oil absorption sponge being arranged in the fixed cavity, the oil absorption portion extending into the oil groove through the communication port; two fixed slots are symmetrically formed on both sides of the oil absorption sponge, the fixed plate being inserted into the fixed slots, the fixed plate being provided with a threaded rod, end portions of the threaded rod extending to an outside of the fixed frame through the oil absorption sponge and a side wall of the fixed cavity, the threaded rod being screwed with the fastening nut at the portions extending to the outside of the fixed frame.

3. The defrosting heater pipe shrinking machine according to claim 2, wherein: a protruding portion extending to a side is formed on a portion of the oil absorption sponge between the fixed plate and the side wall of the fixed cavity, the protruding portion being clamped between the fixed plate and the side wall of the fixed cavity under pressure.

4. The defrosting heater pipe shrinking machine according to claim 2, wherein: the frame is further provided with a guide pipe, one end of the guide pipe being aligned with the oiling channel, the other end of the guide pipe being aligned with the roller pressing channel in the first roller pressing mechanism; an inner diameter of the guide pipe gradually decreases along a direction away from the oiling channel.

5. The defrosting heater pipe shrinking machine according to claim 2, wherein: an oil injection hole is formed in a side wall of the oil groove.

6. The defrosting heater pipe shrinking machine according to any one of claims 1 to 5, wherein: the frame is provided with a first top plate and a second top plate arranged in a V shape, the roller pressing mechanisms being alternately arranged on the first top plate and the second top plate.

7. The defrosting heater pipe shrinking machine according to claim 6, wherein: an oil discharge hole is formed along an extension direction of a junction between the first top plate and the second top plate, a bottom end of the oil discharge hole being vertically provided with an oil guide needle, the frame being provided with an oil collecting box located at bottom portions of all the oil guide needles.

8. The defrosting heater pipe shrinking machine according to claim 7, wherein: an internal portion of the frame is provided with a bearing groove located at a bottom portion of the oil discharge hole, a side wall of the frame being provided with a socket aligned with an end portion of the bearing groove, the oil collecting box being inserted into the bearing groove from the socket.

9. The pipe reducing machine for defrosting heater as claimed in any one of claims 1 to 5, wherein: the roller pressing mechanism further comprises a shaft coupling, a first gear, a second gear, a first rotating shaft, a second rotating shaft, a first adjusting portion and a second adjusting portion; The first rotating shaft is connected with the output end of the driving motor through the coupling, the second rotating shaft is arranged in parallel with the first rotating shaft, the first gear is fixedly sleeved on the outer side of the first rotating shaft, the second gear is fixedly sleeved on the outer side of the second rotating shaft, and the first gear and the second gear are in mesh with each other; the two roller wheels are fixedly sleeved on the outer sides of the first rotating shaft and the second rotating shaft respectively, and the first adjusting part and the second adjusting part are respectively located on the two sides of the two roller wheels and are arranged on the outer sides of the first rotating shaft and the second rotating shaft.

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