Hydraulic drive type cold cutting pipe cutting machine suitable for DN400 caliber or above

Abstract

The hydraulic drive type cold cutting pipe cutting machine comprises a box body unit, a chain, a crawling unit, a hydraulic unit and a milling cutter unit, the crawling unit and the milling cutter unit are both arranged in the box body unit, the hydraulic unit is used for controlling the crawling unit and the milling cutter unit, and the chain is arranged in the box body unit. The crawling unit comprises a main crawling wheel rotationally installed at the bottom of the box body unit, and in the crawling unit of the device, the arranged driven chain wheel unit has a position adjusting function, so that when the whole device is connected with a pipeline, the pipe cutting machine can be combined and matched with a driven chain wheel through a chain; it is guaranteed that the pipe cutting machine can be perfectly attached to the side wall of a to-be-cut pipeline during working, an adjusting screw rod in the milling cutter unit can adjust the position of a cutting blade, the position of the cutting blade can be adjusted in the direction perpendicular to the center of the pipeline within a certain range, and it is guaranteed that the pipeline cutting function of equipment is achieved; and the device is suitable for cutting operation of pipelines with various calibers and wall thicknesses.

Description

Technical Field

[0001] This invention relates to the field of non-fired pipe cutting machine technology, and in particular to a hydraulically driven cold cutting pipe cutting machine suitable for diameters of DN400 and above. Background Technology

[0002] In recent years, along with the rapid development of the national economy, the energy transmission industry has flourished. After years of service, long-distance pipelines are susceptible to damage from long-term factors such as foundation settlement, corrosion, and external construction activities, necessitating pipeline maintenance and emergency repairs. The national standard "Guidelines for Repairing Defects in Buried Steel Pipelines" recommends pipe replacement as the preferred permanent repair method. Pipe replacement requires non-flame cutting of the pipeline using specialized equipment.

[0003] Existing cold cutting equipment mainly includes hydraulically driven self-climbing hydraulic cutting machines and manual pipe cutting machines. Manual pipe cutting machines are only suitable for small-diameter, thin-walled pipe scenarios, and the construction efficiency is also not ideal. Existing hydraulically driven self-climbing hydraulic cutting machines have low working efficiency and cannot be applied to pipes with different wall thicknesses. Summary of the Invention

[0004] This invention proposes a hydraulically driven cold-cutting pipe cutting machine suitable for pipes with a diameter of DN400 and above, in order to solve the problems mentioned in the background art, such as low construction efficiency, low working efficiency, and inability to be applied to pipes with different wall thicknesses.

[0005] The technical solution of this invention is implemented as follows: A hydraulically driven cold-cutting pipe cutting machine suitable for diameters of DN400 and above includes a housing unit, a chain, a crawling unit, a hydraulic unit, and a milling cutter unit. The crawling unit and the milling cutter unit are both located inside the housing unit. The hydraulic unit is used to control the crawling unit and the milling cutter unit. The crawling unit includes a main crawling wheel that is rotatably mounted on the bottom of the housing unit.

[0006] Preferably, the crawling unit further includes a hydraulic motor, a motor support, a connecting shaft, a worm gear, an end cover, a bearing housing, a turbine gear, an output shaft, a small sprocket, and a housing. The motor support and the housing are both fixedly installed inside the housing unit. The hydraulic motor is fixedly installed on the motor support. The connecting shaft is fixedly installed on the output end of the hydraulic motor. The worm gear is fixedly installed on the end of the connecting shaft away from the hydraulic motor. The end of the worm gear away from the connecting shaft is rotatably installed on the end cover via a bearing. The end cover is fixedly installed on the housing. The bearing housing is fixedly installed on the housing. The connecting shaft is rotatably installed on the bearing housing via a bearing. The turbine gear meshes with the worm gear. The turbine gear is fixedly installed on the outer surface of the output shaft. One end of the output shaft is rotatably installed on one side of the housing. The other end of the output shaft passes through the other side of the housing and extends to the outside of the housing. The small sprocket is fixedly installed on the outer surface of the end of the output shaft that extends to the outside of the housing.

[0007] Preferably, the crawling unit further includes a large sprocket unit, which includes a large sprocket, a drive shaft, a bearing cover, and a bushing. The large sprocket is connected to a small sprocket via a chain and is fixedly mounted on the outer surface of the drive shaft. One end of the drive shaft is rotatably mounted on the bearing cover via a bearing, and the other end of the drive shaft passes through the bushing and extends to the outside of the bushing. The bushing is fixedly mounted on the housing. A drive sprocket is connected to the other side of the drive shaft of the large sprocket unit.

[0008] Preferably, the crawling unit further includes a driven sprocket unit, which includes a pull rod, a guide rail, a slider, and a driven sprocket. The driven sprocket is connected to the driving sprocket and the crawling unit via a chain and is fixed to the pipe by winding.

[0009] Preferably, the guide rail is fixedly installed on the housing unit, the slider is slidably installed on the guide rail, the driven sprocket is fixedly installed on the slider, and the pull rod is fixedly installed on the slider.

[0010] Preferably, the milling cutter unit includes a second hydraulic motor, a short shaft, a second worm gear, a turbine housing, a rear cover, a second worm gear, a milling cutter shaft, a tool holder, a guide post, and a lock nut. The turbine housing is threaded onto an adjusting screw, which is rotatably mounted on the housing unit. The second hydraulic motor is fixedly mounted on the outside of the housing unit. The short shaft is rotatably mounted inside the housing unit, with its two ends fixedly mounted to the output end of the hydraulic motor and the second worm gear, respectively. The end of the second worm gear away from the short shaft is rotatably mounted inside the turbine housing. The second worm gear meshes with the second worm gear and is fixedly mounted on the outer surface of the milling cutter shaft. One end of the milling cutter shaft is rotatably mounted on the rear cover via a bearing, and the rear cover is fixedly mounted on one side of the turbine housing. One end of the milling cutter shaft passes through the other side of the turbine housing and extends to the outside of the turbine housing. The tool holder is mounted on the outer surface of the end of the milling cutter shaft that extends to the outside of the turbine housing. The guide post is mounted on the tool holder, and the cutting tool is mounted on the tool holder via the guide post and then secured by the lock nut.

[0011] Preferably, the turbine housing has a guide hole, and a guide rod that cooperates with the guide hole is fixedly installed inside the housing unit. The turbine housing is slidably installed on the guide rod through the guide hole.

[0012] Preferably, the housing unit has a through slot for the hydraulic motor to move up and down.

[0013] Preferably, the hydraulic unit includes a valve block, a hose, and a quick connector. The valve block is fixedly installed on the housing unit, and the valve block is connected to hydraulic motor one and hydraulic motor two via hoses.

[0014] Preferably, the housing unit has a notch for the overall lifting and lowering of the turbine shaft, milling cutter shaft, tool holder, guide post, and lock nut.

[0015] By adopting the above technical solution, the beneficial effects of the present invention are as follows: In the crawling unit of the device of the present invention, the driven sprocket unit has a position adjustment function. The position adjustment function allows the pipe cutter to perfectly fit the side wall of the pipe to be cut when the entire device is connected to the pipe through the combination of chain and driven sprocket. The adjusting screw in the milling cutter unit can adjust the position of the cutting blade, so that the position of the cutting blade can be adjusted within a certain range in the direction perpendicular to the center of the pipe, ensuring that the pipe cutting function of the device is realized, and it is suitable for pipe cutting operations of various diameters and wall thicknesses.

[0016] The device of this invention has a simple and compact structure, without any redundant design. The equipment is also lightweight and can be moved and installed on-site by manual handling. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a front view schematic diagram of the device of the present invention; Figure 2 This is a front view schematic diagram of the crawling unit of the device of the present invention; Figure 3 This is a side view of the crawling unit of the device of the present invention; Figure 4 This is a front view schematic diagram of the main sprocket of the crawling unit of the device of the present invention; Figure 5 This is a front view schematic diagram of the driven sprocket of the crawling unit of the device of the present invention; Figure 6 This is a front view schematic diagram of the milling cutter unit of the device of the present invention; Figure 7 This is a side view of the milling cutter unit of the device of the present invention.

[0019] in: 1. Housing unit; 2. Crawler unit; 3. Hydraulic unit; 4. Milling cutter unit; 2-1. Hydraulic motor one; 2-2. Motor support; 2-3. Connecting shaft; 2-4. Worm gear one; 2-5. End cover; 2-6. Bearing housing; 2-7. Turbine gear one; 2-8. Output shaft; 2-9. Small sprocket; 2-10. Housing cover; 2-11. Housing; 2-12. Bearing cover; 2-13. Drive shaft; 2-14. Large sprocket; 2- 15. Bushing; 2-16. Drive sprocket; 2-17. Tie rod; 2-18. Guide rail; 2-19. Slider; 2-20. Driven sprocket; 4-1. Hydraulic motor II; 4-2. Short shaft; 4-3. Worm gear II; 4-4. Rear end cover; 4-5. Turbine housing; 4-6. Adjusting screw; 4-7. Rear cover; 4-8. Turbine gear II; 4-9. Milling cutter shaft; 4-10. Tool holder; 4-11. Guide post; 4-12. Lock nut. Implementation The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] See Figure 1-7A hydraulically driven cold-cutting pipe cutting machine suitable for diameters of DN400 and above includes a housing unit 1, a chain, a crawling unit 2, a hydraulic unit 3, and a milling cutter unit 4. The crawling unit 2 and the milling cutter unit 4 are both located inside the housing unit 1. The hydraulic unit 3 is used to control the crawling unit 2 and the milling cutter unit 4. The crawling unit 2 includes a main crawling wheel that is rotatably mounted on the bottom of the housing unit 1.

[0021] The crawling unit 2 also includes a hydraulic motor 2-1, a motor support 2-2, a connecting shaft 2-3, a worm gear 2-4, an end cover 2-5, a bearing housing 2-6, a worm wheel 2-7, an output shaft 2-8, a small sprocket 2-9, and a housing 2-11. The motor support 2-2 and the housing 2-11 are both fixedly installed inside the housing unit 1. The hydraulic motor 2-1 is fixedly installed on the motor support 2-2. The connecting shaft 2-3 is fixedly installed on the output end of the hydraulic motor 2-1. The worm gear 2-4 is fixedly installed on the end of the connecting shaft 2-3 away from the hydraulic motor 2-1. The end of the worm gear 2-4 away from the connecting shaft 2-3 is connected via... The bearing is rotatably mounted on the end cover 2-5, the end cover 2-5 is fixedly mounted on the housing 11, the bearing seat 2-6 is fixedly mounted on the housing 11, the connecting shaft 2-3 is rotatably mounted on the bearing seat 2-6 via the bearing, the worm gear 2-7 is meshed with the worm 2-4, the worm gear 2-7 is fixedly mounted on the outer surface of the output shaft 2-8, one end of the output shaft 2-8 is rotatably mounted on one side of the housing 2-11, the other end of the output shaft 2-8 passes through the other side of the housing 2-11 and extends to the outside of the housing 2-11, and the small sprocket 2-9 is fixedly mounted on the outer surface of the end of the output shaft 2-8 that extends to the outside of the housing 2-11; The top of the box 2-11 is fixedly installed with a box cover 2-10.

[0022] Hydraulic motor 2-1 drives connecting shaft 2-3 to rotate. During the rotation of connecting shaft 2-3, worm gear 2-4 can rotate synchronously. During the rotation of worm gear 2-4, worm gear 2-7 can rotate. During the rotation of worm gear 2-7, output shaft 2-8 can rotate. During the rotation of output shaft 2-8, small sprocket 2-9 can rotate. Under the action of hydraulic motor 2-1, small sprocket 2-9 can be driven to rotate.

[0023] The crawling unit 2 also includes a large sprocket unit, which includes a large sprocket 2-14, a drive shaft 2-13, a bearing cover 2-12, and a bushing 2-15. The large sprocket 2-14 is connected to the small sprocket 2-9 via a chain, and the large sprocket 2-14 is fixedly installed on the outer surface of the drive shaft 2-13. One end of the drive shaft 2-13 is rotatably installed on the bearing cover 2-12 via a bearing, and the other end of the drive shaft 2-13 passes through the bushing 2-15 and extends to the outside of the bushing 2-15. The bushing 2-15 is fixedly installed on the housing 2-11. The other side of the drive shaft 2-13 of the large sprocket unit is connected to a drive sprocket 2-16. Under the action of hydraulic motor 2-1, the small sprocket 2-9 can be driven to rotate, and the large sprocket 2-14 can be driven to rotate synchronously through the chain. During the rotation of the large sprocket 2-14, the drive shaft 2-13 can be driven to rotate, and the drive shaft 2-13 can be driven to rotate. That is, under the action of hydraulic motor 2-1, the drive sprocket 2-16 can be driven to rotate.

[0024] The crawling unit 2 also includes a driven sprocket unit, which includes a pull rod 2-17, a guide rail 2-18, a slider 2-19, and a driven sprocket 2-20. The driven sprocket 2-20 is connected to the driving sprocket 2-16 and the crawling unit 2 by a chain and is fixed to the pipe by winding. During the rotation of the drive sprocket 2-16 driven by the hydraulic motor 2-1, the drive sprocket 2-16 can drive the driven sprocket 2-20 to rotate via a chain. Since the driven sprocket 2-20 is connected to the drive sprocket 2-16 and the crawling unit 2 via a chain and is fixed to the pipe by winding, the pipe cutter can crawl on the pipe to be cut during the rotation of the drive sprocket 2-16 and the driven sprocket 2-20.

[0025] Guide rail 2-18 is fixedly installed on housing unit 1, slider 2-19 is slidably installed on guide rail 2-18, driven sprocket 2-20 is fixedly installed on slider 2-19, and pull rod 2-17 is fixedly installed on slider 2-19; Pulling the lever 2-17 causes the slider 2-19 to slide on the guide rail 2-18. During the sliding process, the slider 2-19 can drive the driven sprocket 2-20 to move synchronously. That is, by adjusting the lever 2-17, the driven sprocket 2-20 is caused to move left and right on the guide rail 2-18. With the help of chains of different lengths (the chain length is adjusted according to the pipe diameter), the entire pipe cutting machine can be coiled and secured on the pipe to be cut.

[0026] The milling cutter unit 4 includes a hydraulic motor 4-1, a short shaft 4-2, a worm gear 4-3, a turbine housing 4-5, a rear cover 4-7, a worm gear 4-3, a milling cutter shaft 4-9, a cutter holder 4-10, a guide post 4-11, and a lock nut 4-12. The turbine housing 4-5 is threaded onto an adjusting screw 4-6, which is rotatably mounted on the housing unit 1. The hydraulic motor 4-1 is fixedly mounted on the outside of the housing unit 1. The short shaft 4-2 is rotatably mounted inside the housing unit 1, with both ends of the short shaft 4-2 fixedly mounted to the output end of the hydraulic motor 4-1 and the worm gear 4-3, respectively. The end of the worm gear 4-3 furthest from the short shaft 4-2 is rotatably mounted on the turbine housing 4-5. Inside 5, the second worm gear 4-8 meshes with the second worm gear 4-3, and the second worm gear 4-8 is fixedly installed on the outer surface of the milling cutter shaft 4-9. One end of the milling cutter shaft 4-9 is rotatably installed on the rear cover 4-7 through a bearing, and the rear cover 4-7 is fixedly installed on one side of the worm gear housing 4-5. One end of the milling cutter shaft 4-9 passes through the other side of the worm gear housing 4-5 and extends to the outside of the worm gear housing 4-5. The tool holder 4-10 is installed on the outer surface of the end of the milling cutter shaft 4-9 that extends to the outside of the worm gear housing 4-5. The guide post 4-11 is installed on the tool holder 4-10. The cutting tool is installed on the tool holder 4-10 through the guide post 4-11 and then fastened by the lock nut 4-12. Specifically, the end of the worm gear 4-3 away from the short shaft 4-2 is rotatably mounted inside the rear end cover 4-4, and the rear end cover 4-4 is fixedly mounted inside the turbine housing 4-5.

[0027] Hydraulic motor 4-1 drives short shaft 4-2 to rotate. During the rotation of short shaft 4-2, worm gear 4-3 rotates synchronously. Worm gear 4-3 rotates, which in turn drives turbine 4-8 to rotate. Turbine 4-8 rotates, which in turn drives milling cutter shaft 4-9 to rotate. Milling cutter shaft 4-9 rotates, which in turn drives cutting tool to rotate. The cutting tool can cut the pipe during rotation. That is, under the action of hydraulic motor 4-1, the cutting tool can be driven to cut the pipe to be cut; at the same time, with the cooperation of crawling unit 2, crawling cutting of the pipe is realized.

[0028] The turbine housing 4-5 has a guide hole, and a guide rod that matches the guide hole is fixedly installed inside the housing unit 1. The turbine housing 4-5 is slidably installed on the guide rod through the guide hole. By rotating the adjusting screw 4-6, since the adjusting screw 4-6 is threadedly connected to the turbine housing 4-5, the turbine housing 4-5 can move downwards when the adjusting screw 4-6 is rotated clockwise. The downward movement of the turbine housing 4-5 can drive the entire milling cutter unit 4 (excluding the adjusting screw 4-6) to move downwards. Similarly, the counterclockwise rotation of the adjusting screw 4-6 can cause the entire milling cutter unit 4 (excluding the adjusting screw 4-6) to move upwards. That is, the turbine housing 4-5 is fixed inside the housing unit 1 through the adjusting screw 4-6 and has the function of vertical adjustment. The guide hole and guide block prevent the turbine housing 4-5 from rotating with the adjusting screw 4-6, and instead allow the turbine housing 4-5 to move up and down along the adjusting screw 4-6, and guide the movement of the turbine housing 4-5.

[0029] The housing unit 1 has a through slot for the hydraulic motor 4-1 to move up and down; the through slot allows the hydraulic motor 4-1 to follow the turbine housing 4-5 to move up and down.

[0030] The housing unit 1 has a notch for the overall lifting and lowering of the turbine 4-8, milling cutter shaft 4-9, tool holder 4-10, guide post 4-11, and lock nut 4-12. The notch is designed to allow the cutting tool installed on the tool holder 4-10 to cut the pipe, and also to allow the turbine 4-8, milling cutter shaft 4-9, tool holder 4-10, guide post 4-11, and lock nut 4-12 to move up and down with the turbine housing 4-5.

[0031] The hydraulic unit 3 includes a valve block, a hose, and a quick connector. The valve block is fixedly installed on the housing unit 1, and the valve block is connected to the hydraulic motor 2-1 and the hydraulic motor 4-1 via a hose. Under the action of the hydraulic unit 3, the start and stop of the hydraulic motor 2-1 and the hydraulic motor 4-1 can be controlled, thereby controlling the pipe cutter's cutting of the pipe and the pipe cutter's crawling.

[0032] The housing unit 1 is fixedly equipped with a handle for easy handling, which makes it easy for users to move and transport the pipe cutter.

[0033] In this embodiment, based on the design of the ratio between the pipe cutting machine's running speed and the milling cutter speed, the hydraulic motor 2-1 is a cycloidal motor BMR-400, and the hydraulic motor 4-1 is a cycloidal motor BMRS-100. The worm gear 2-4 has a module m=2, number of threads Z=1, and pitch circle diameter d=22.4; the turbine gear 2-7 has a module m=2 and number of teeth Z=39. The worm gear 2 4-3 has a module m=2, number of threads Z=3, and pitch circle diameter d=35.5; the turbine gear 2 4-8 has a module m=2 and number of teeth Z=27.

[0034] Working principle: Place the entire pipe cutter directly above the pipe to be cut, and use a chain to pass around the drive sprocket 2-20, the driven sprocket 2-16, and the pipe respectively, and tighten it by adjusting the tie rod 2-17. Turn on the pipe cutter's liquid unit 3, and manually and slowly adjust the adjusting screw 4-6 until the blade cuts through the pipe. Then, control the valves and flow control elements on the hydraulic unit 3 to start and adjust the pipe cutter's crawling speed until the pipe is finally cut. Close the valves and dismantle the pipe cutter in sequence.

[0035] In summary, the driven sprocket unit in the crawling unit 2 of the device of the present invention has a position adjustment function. The position adjustment function allows the pipe cutter to perfectly fit the side wall of the pipe to be cut when the entire device is connected to the pipe through the combination of chain and driven sprocket. The adjusting screws 4-6 in the milling cutter unit 4 can adjust the position of the cutting blade, so that the position of the cutting blade can be adjusted within a certain range in the direction perpendicular to the center of the pipe, ensuring that the pipe cutting function of the device is realized, and it is suitable for pipe cutting operations of various diameters and wall thicknesses.

[0036] The device of this invention has a simple and compact structure, without any redundant design. The equipment is also lightweight and can be moved and installed on-site by manual handling.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A hydraulically driven cold-cutting pipe cutting machine suitable for diameters of DN400 and above, characterized in that: It includes a housing unit (1), a chain, a crawling unit (2), a hydraulic unit (3), and a milling cutter unit (4). The crawling unit (2) and the milling cutter unit (4) are both located inside the housing unit (1). The hydraulic unit (3) is used to control the crawling unit (2) and the milling cutter unit (4). The crawling unit (2) includes a main crawling wheel that is rotatably mounted on the bottom of the housing unit (1).

2. The hydraulically driven cold-cutting pipe cutting machine suitable for diameters of DN400 and above as described in claim 1, characterized in that: The crawling unit (2) further includes a hydraulic motor (2-1), a motor support (2-2), a connecting shaft (2-3), a worm gear (2-4), an end cap (2-5), a bearing seat (2-6), a turbine (2-7), an output shaft (2-8), a small sprocket (2-9), and a housing (2-11). The motor support (2-2) and the housing (2-11) are both fixedly installed inside the housing unit (1). The hydraulic motor (2-1) is fixedly installed on the motor support (2-2). The connecting shaft (2-3) is fixedly installed at the output end of the hydraulic motor (2-1). The worm gear (2-4) is fixedly installed at the end of the connecting shaft (2-3) away from the hydraulic motor (2-1). The bearing is rotatably mounted on the end cover (2-5), which is fixedly mounted on the housing (11). The bearing seat (2-6) is fixedly mounted on the housing (11). The connecting shaft (2-3) is rotatably mounted on the bearing seat (2-6) via the bearing. The first worm gear (2-7) is meshed with the first worm (2-4). The first worm gear (2-7) is fixedly mounted on the outer surface of the output shaft (2-8). One end of the output shaft (2-8) is rotatably mounted on one side of the housing (2-11). The other end of the output shaft (2-8) passes through the other side of the housing (2-11) and extends to the outside of the housing (2-11). The small sprocket (2-9) is fixedly mounted on the outer surface of the end of the output shaft (2-8) that extends to the outside of the housing (2-11).

3. A hydraulically driven cold-cutting pipe cutting machine suitable for DN400 and above diameters according to claim 2, characterized in that: The crawling unit (2) also includes a large sprocket unit, which includes a large sprocket (2-14), a drive shaft (2-13), a bearing cover (2-12), and a bushing (2-15). The large sprocket (2-14) is connected to the small sprocket (2-9) via a chain, and the large sprocket (2-14) is fixedly installed on the outer surface of the drive shaft (2-13). One end of the drive shaft (2-13) is rotatably installed on the bearing cover (2-12) via a bearing, and the other end of the drive shaft (2-13) passes through the bushing (2-15) and extends to the outside of the bushing (15). The bushing (2-15) is fixedly installed on the housing (2-11). The other side of the drive shaft (2-13) of the large sprocket unit is connected to a drive sprocket (2-16).

4. A hydraulically driven cold-cutting pipe cutting machine suitable for diameters of DN400 and above, as described in claim 3, characterized in that: The crawling unit (2) also includes a driven sprocket unit, which includes a pull rod (2-17), a guide rail (2-18), a slider (2-19), and a driven sprocket (2-20). The driven sprocket (2-20) is connected to the driving sprocket (2-16) and the crawling unit (2) by a chain and is fixed to the pipe by winding.

5. A hydraulically driven cold-cutting pipe cutting machine suitable for DN400 and above diameters according to claim 4, characterized in that: The guide rail (2-18) is fixedly installed on the housing unit (1), the slider (2-19) is slidably installed on the guide rail (2-18), the driven sprocket (2-20) is fixedly installed on the slider (2-19), and the pull rod (2-17) is fixedly installed on the slider (2-19).

6. A hydraulically driven cold-cutting pipe cutting machine suitable for DN400 and above diameters according to claim 2, characterized in that: The milling cutter unit (4) includes a second hydraulic motor (4-1), a short shaft (4-2), a second worm gear (4-3), a turbine housing (4-5), a rear cover (4-7), a second turbine gear (4-8), a milling cutter shaft (4-9), a cutter holder (4-10), a guide post (4-11), and a lock nut (4-12). The turbine housing (4-5) is threaded onto an adjusting screw (4-6), which is rotatably mounted on the housing unit (1). The second hydraulic motor (4-1) is fixedly mounted on the outside of the housing unit (1). The short shaft (4-2) is rotatably mounted inside the housing unit (1), and both ends of the short shaft (4-2) are fixedly mounted to the output end of the hydraulic motor (4-1) and the second worm gear (4-3), respectively. The end of the second worm gear (4-3) away from the short shaft (4-2) is rotatably mounted on the turbine. Inside the housing (4-5), the second turbine (4-8) is meshed with the second worm (4-3), and the second turbine (4-8) is fixedly installed on the outer surface of the milling cutter shaft (4-9). One end of the milling cutter shaft (4-9) is rotatably installed on the rear cover (4-7) through a bearing, and the rear cover (4-7) is fixedly installed on one side of the turbine housing (4-5). One end of the milling cutter shaft (4-9) passes through the other side of the turbine housing (4-5) and extends to the outside of the turbine housing (4-5). The tool holder (4-10) is installed on the outer surface of the end of the milling cutter shaft (4-9) that extends to the outside of the turbine housing (4-5). The guide post (4-11) is installed on the tool holder (4-10). The cutting tool is installed on the tool holder (4-10) through the guide post (4-11) and then secured by the lock nut (4-12).

7. A hydraulically driven cold-cutting pipe cutting machine suitable for DN400 and above diameters according to claim 6, characterized in that: The turbine housing (4-5) has a guide hole, and a guide rod that matches the guide hole is fixedly installed inside the housing unit (1). The turbine housing (4-5) is slidably installed on the guide rod through the guide hole.

8. A hydraulically driven cold-cutting pipe cutting machine suitable for DN400 and above diameters according to claim 6, characterized in that: The housing unit (1) has a through slot for the hydraulic motor (4-1) to move up and down.

9. A hydraulically driven cold-cutting pipe cutting machine suitable for DN400 and above diameters according to claim 6, characterized in that: The hydraulic unit (3) includes a valve block, a hose and a quick connector. The valve block is fixedly installed on the housing unit (1), and the valve block is connected to the first hydraulic motor (2-1) and the second hydraulic motor (4-1) through the hose.

10. A hydraulically driven cold-cutting pipe cutting machine suitable for DN400 and above diameters according to claim 6, characterized in that: The housing unit (1) has a notch for the overall lifting and lowering of the turbine 2 (4-8), milling cutter shaft (4-9), tool holder (4-10), guide post (4-11) and lock nut (4-12).

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