Device capable of plating refractory metal on the inner wall surface of a tubular workpiece

Abstract

The utility model relates to an equipment that can carry out refractory metal coating on the inner wall surface of tubular workpiece, adopts the rotation cathode lifting device and tubular workpiece rotation device drive several rotation cathodes and several tubular workpiece rotation devices simultaneously, and the lower part of rotation cathode is correspondingly inserted into the tubular workpiece for coating; adopts three multilayer telescopic vacuum cavity structure, and through servo electric cylinder lifting linkage control upper cover plate and lower cover, double covers are opened synchronously when stopping to maintain the inner wall of cavity, and the closed cavity makes the rotation multi-arc cathode target probe into the workpiece bore when working, solve the technical problems such as poor inner wall coating uniformity, low refractory metal ionization rate and insufficient coating ablation resistance when coating refractory metal and other metals on the inner wall of long and narrow workpiece (length-diameter ratio > 30: 1) in the existing coating equipment.

Description

Technical Field

[0001] The embodiments of this utility model relate to an apparatus for coating refractory metals, and more particularly to an apparatus for coating refractory metals on the inner wall surface of a tubular workpiece. Background Technology

[0002] In existing coating equipment, when coating the inner wall of long and narrow workpieces (length-to-diameter ratio > 30:1) with refractory metals (W, Ta, Mo, Nb), there are drawbacks such as poor coating uniformity, low ionization rate of refractory metals (W, Ta, Mo, Nb), and insufficient coating ablation resistance. These drawbacks are particularly evident in long and narrow workpieces (length-to-diameter ratio > 30:1) such as artillery muzzle brakes and rocket nozzles. Utility Model Content

[0003] The purpose of this invention is to provide a technology to solve the problems of poor coating uniformity on the inner wall of long and narrow workpieces (length-to-diameter ratio > 30:1), low ionization rate of refractory metals (W, Ta, Mo, Nb), and insufficient coating ablation resistance. This invention designs a coil-enhanced rotating multi-arc ion plating device to achieve full-surface ion plating of irregularly shaped workpieces, especially long and narrow workpieces (length-to-diameter ratio > 30:1).

[0004] To achieve the above objectives, this utility model provides an apparatus for depositing a refractory metal film on the inner wall surface of a tubular workpiece, comprising: Coating chamber; A top cover plate is provided above the coating chamber; A rotating cathode is provided above the upper cover plate; A rotating cathode lifting device is provided on both sides of the upper cover plate; The lower cover plate is disposed below the coating chamber; A tubular workpiece lifting device, wherein several tubular workpiece lifting devices are arranged on both sides of the lower cover plate; A tubular workpiece rotating device is provided above the lower cover plate; a tubular workpiece is fixed on the tubular workpiece rotating device. The rotating cathode lifting device and the tubular workpiece rotating device respectively drive several rotating cathodes and several tubular workpiece rotating devices to move up and down, so that the lower part of the rotating cathode is inserted into the tubular workpiece one by one for coating.

[0005] Furthermore, in the device for coating refractory metals on the inner wall surface of a tubular workpiece according to the present invention, a plurality of heaters are fixed in the coating chamber; the tubular workpiece is positioned inside the heaters, the heaters heat the tubular workpiece, and the lower part of the rotating cathode extends into the tubular workpiece to perform heating and coating simultaneously.

[0006] Furthermore, in the device for coating refractory metals on the inner wall surface of a tubular workpiece as described in this utility model, a vacuum pump assembly is fixedly connected to one side of the coating chamber.

[0007] Furthermore, in the device for coating refractory metals on the inner wall surface of a tubular workpiece according to the present invention, the coating chamber is cylindrical, and a plurality of heaters are evenly fixed inside the coating chamber by a support frame.

[0008] Furthermore, in the apparatus for depositing refractory metal films on the inner wall surface of a tubular workpiece according to this invention, the rotating cathode further includes: A cathode rotation drive component is disposed above the upper cover plate; Cathode; the cathode is driven and connected below the cathode rotation drive component, the cathode passes through the upper cover plate into the tubular workpiece; the cathode rotation drive component drives the cathode to rotate in the tubular workpiece.

[0009] Furthermore, in the device for depositing refractory metal coatings on the inner wall surface of a tubular workpiece according to this invention, the cathode rotation drive component further includes: A cathode rotary motor, the outer casing of which is fixed above the upper cover plate by a fixing bracket; A cathode rotating drive wheel is fixed on the motor shaft of the cathode rotating motor; A cathode bearing housing, with the outer shell of the cathode bearing housing fixed above the upper cover plate; The cathode is fixedly connected at one end in the bearing hole of the cathode bearing housing; the other end of the cathode passes through the upper cover plate. A cathode rotating passive wheel is fixedly connected to the cathode above the cathode bearing seat; A cathode rotating synchronous belt is connected to the cathode rotating drive pulley and the cathode rotating driven pulley; the cathode rotating motor drives the cathode to rotate through the cathode rotating synchronous belt.

[0010] Furthermore, in the device for coating refractory metals on the inner wall surface of a tubular workpiece as described in this utility model, the rotating cathode lifting device is a first servo electric cylinder; the movable end of the first servo electric cylinder is connected and fixed to the edge of the upper cover plate; the fixed end of the first servo electric cylinder is fixedly connected to the top of the frame.

[0011] Furthermore, in the equipment for coating refractory metals on the inner wall surface of a tubular workpiece according to this utility model, the tubular workpiece lifting device is a second servo electric cylinder; the movable end of the second servo electric cylinder is connected and fixed to the edge of the lower cover plate; the fixed end of the second servo electric cylinder is fixedly connected to the bottom of the frame.

[0012] Furthermore, in the apparatus for coating refractory metals on the inner wall surface of a tubular workpiece according to this invention, the tubular workpiece rotating device further includes: A rotary motor for tubular workpieces, with the outer casing of the rotary motor fixed below the lower cover plate; A drive wheel for rotating the tubular workpiece is fixedly connected to the motor shaft of the motor for rotating the tubular workpiece. A tubular workpiece bearing housing, with the outer shell of the tubular workpiece bearing housing fixed above the lower cover plate; A tubular workpiece spindle is fixedly connected at one end in the bearing hole of the tubular workpiece bearing seat; the other end of the tubular workpiece spindle passes through the lower cover plate. A driven wheel for rotating a tubular workpiece is fixedly connected to the main shaft of the tubular workpiece above the bearing seat of the tubular workpiece. A synchronous belt for rotating the tubular workpiece is connected to the driving wheel and the driven wheel of the tubular workpiece; the motor for rotating the tubular workpiece drives the tubular workpiece to rotate via the synchronous belt. A tubular workpiece rotating plate is movably connected to the main shaft of the tubular workpiece via a bearing above the lower cover plate. A driving gear for rotating the tubular workpiece is fixedly connected to the other end of the main shaft of the tubular workpiece, above the rotating plate of the tubular workpiece. A passive rotating gear for rotating a tubular workpiece is movably connected to a rotating plate of the tubular workpiece via bearings; all of the passive rotating gears for rotating the tubular workpiece mesh with the active rotating gear for rotating the tubular workpiece. A workpiece holder is fixed above the passive rotating gear of the tubular workpiece; the tubular workpiece is fixed in the workpiece holder; The rotary motor drives the main shaft of the tubular workpiece to rotate, which in turn drives the active rotary gear of the tubular workpiece to rotate the passive rotary gear, causing the tubular workpiece to rotate.

[0013] Furthermore, in the device for depositing a refractory metal coating on the inner wall surface of a tubular workpiece according to this invention, the heater further includes: A support frame, wherein several layers of the support frame are fixed inside the coating chamber; An electromagnetic induction coil is fixed inside any one of the support frames. A heating coil is fixed inside any one of the electromagnetic induction coils; Several electromagnetic induction coils and several heating coils are stacked together, such that the central hole is on the same axis; the tubular workpiece is disposed in the central hole.

[0014] Compared with the prior art, the embodiment of this utility model adopts an upper cover plate above the coating chamber; several rotating cathodes are arranged above the upper cover plate; rotating cathode lifting devices are arranged on both sides of the upper cover plate; a lower cover plate is arranged below the coating chamber; several tubular workpiece lifting devices are arranged on both sides of the lower cover plate; a tubular workpiece rotating device is arranged above the lower cover plate; and tubular workpieces are fixed on the tubular workpiece rotating device. The rotating cathode lifting device and the tubular workpiece rotating device drive several rotating cathodes and several tubular workpiece rotating devices respectively, so that the lower part of the rotating cathode is inserted into the tubular workpiece one by one for coating. Because this utility model adopts a three-layer telescopic vacuum chamber structure, the upper cover plate (used for target replacement and maintenance) and the lower cover (used for workpiece clamping) are controlled by servo electric cylinder lifting linkage. When the machine stops, the two covers open synchronously to facilitate maintenance of the inner wall of the chamber. When working, the chamber is sealed so that the rotating multi-arc cathode target is inserted into the workpiece bore. The structural design facilitates workpiece clamping and equipment maintenance. The heater in this invention is integrated into the middle layer of the equipment, with a layered design of internal heaters and coils, allowing for individual adjustment of heating temperature and magnetic field strength. To ensure uniform heating of the workpiece during the coating process, the heating device adopts a three-stage adjustable structure; the ring coil structure is sealed in a water-cooling device, reducing localized overheating caused by the electromagnetic coil while ensuring a strong magnetic field strength. Simultaneously, the tubular workpiece is clamped in the lower layer, and the chassis assembly is designed with a transmission component driving a large gear to rotate the workstations, enabling each workstation to rotate synchronously and uniformly during operation. Each workstation is also individually connected to process gas, improving film uniformity. The current of several coils can be individually controlled; by adjusting the current magnitude and direction, magnetic fields of different magnitudes and directions can be generated and coupled with the multi-arc rotation to achieve coating on the inner surface of irregularly shaped workpieces. Individual and uniform gas distribution within each tubular workpiece ensures uniform coating. This invention solves the problems in existing coating equipment when coating the inner walls of long and narrow workpieces (length-to-diameter ratio > 30:1) with refractory metals (W, Ta, Mo, Nb), such as poor coating uniformity, low ionization rate of refractory metals (W, Ta, Mo, Nb), and insufficient coating ablation resistance. These problems are particularly prominent for long and narrow workpieces (length-to-diameter ratio > 30:1) such as artillery muzzle brakes and rocket nozzles. Attached Figure Description

[0015] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 for Figure 1 Front view diagram; Figure 3 This is a schematic diagram of the left view in direction AA; Figure 4 This is a schematic diagram of the rotating cathode of this utility model from the front view direction; Figure 5 This is a top view of the rotating cathode of this utility model; Figure 6 This is a schematic diagram of the front view of the tubular workpiece rotating device of this utility model; Figure 7 This is a schematic diagram of the BB direction of the tubular workpiece rotating device of this utility model; Figure 8 This is a partial enlarged view of point A of this utility model; Figure 9 This is a partial enlarged view of section B of this utility model. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this utility model clearer, the various embodiments of this utility model will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this utility model to facilitate a better understanding of this application. However, the technical solutions claimed in the claims of this application can be implemented even without these technical details and with various variations and modifications based on the following embodiments.

[0017] The embodiments of this utility model relate to a device capable of depositing a refractory metal film on the inner wall surface of a tubular workpiece, such as... Figures 1-9 As shown, it includes: The coating chamber 1 is located in the middle of the apparatus in this embodiment that can perform refractory metal coating on the inner wall surface of a tubular workpiece; A top cover plate 2 is provided above the coating chamber 1; the top cover plate 2 is used to install a rotating cathode 10 on the upper part of the equipment that can perform refractory metal coating on the inner wall surface of the tubular workpiece in this embodiment. Several rotating cathodes 10 are arranged above the upper cover plate 2; the rotating cathodes 10 are used in this embodiment to perform coating on the inner wall surface of the tubular workpiece by the equipment capable of coating refractory metals.

[0018] Rotary cathode lifting devices 4 are installed on both sides of the upper cover plate 2; the rotary cathode lifting devices 4 drive the upper cover plate 2 to move up and down.

[0019] A lower cover plate 3 is installed below the coating chamber 1; the lower cover plate 3 is used for mounting... Several tubular workpiece lifting devices 5 are set on both sides of the lower cover plate 3; the tubular workpiece lifting devices 5 drive the lower cover plate 3 to move up and down.

[0020] A tubular workpiece rotating device 20 is provided above the lower cover plate 3; a tubular workpiece 6 is fixed on the tubular workpiece rotating device 20; the tubular workpiece rotating device 20 is used to fix and rotate the tubular workpiece 6.

[0021] The rotating cathode lifting device 4 and the tubular workpiece rotating device 5 respectively drive several rotating cathodes 10 and several tubular workpiece rotating devices 20 to move up and down, so that the lower part of the rotating cathode 10 is inserted into the tubular workpiece 6 one by one for coating.

[0022] This embodiment employs a three-layer retractable vacuum chamber structure, where a rotating cathode lifting device 4 and a tubular workpiece rotating device 5 drive several rotating cathodes 10 and several tubular workpiece rotating devices 20 to move up and down. A servo electric cylinder controls the lifting and linkage of the upper cover (for target replacement and maintenance) and the lower cover (for workpiece clamping). When the machine stops, both covers open synchronously for easy maintenance of the inner wall of the chamber. During operation, the sealed chamber allows the rotating multi-arc cathode target to penetrate the workpiece bore. The structural design facilitates workpiece clamping and equipment maintenance. The heater in this invention is integrated into the middle layer of the equipment, with internal heaters and coils designed in layers, allowing for independent adjustment of heating temperature and magnetic field strength. To ensure uniform heating during the workpiece coating process, the heating device adopts a three-section adjustable structure; the ring coil structure is sealed in a water-cooling device, reducing localized overheating caused by the electromagnetic coil while ensuring a strong magnetic field strength. Simultaneously, the tubular workpiece is clamped in the lower layer. The chassis assembly design uses a transmission component to drive a large gear to rotate the workstations, ensuring that each workstation rotates synchronously and uniformly during operation. Furthermore, each workstation is individually connected to process gas, improving film uniformity. The current of several coils can be controlled individually. By adjusting the magnitude and direction of the current, magnetic fields of different magnitudes and directions can be generated and coupled with rotating multi-arc coupling to achieve coating on the inner surface of irregularly shaped workpieces. Uniform gas distribution within each tubular workpiece ensures coating uniformity. This solves the problems inherent in existing coating equipment when coating the inner walls of long and narrow workpieces (length-to-diameter ratio > 30:1) with refractory metals (W, Ta, Mo, Nb), including poor coating uniformity, low ionization rate of refractory metals (W, Ta, Mo, Nb), and insufficient coating ablation resistance. These problems are particularly pronounced in long and narrow workpieces (length-to-diameter ratio > 30:1) such as artillery muzzle brakes and rocket nozzles.

[0023] To achieve the aforementioned technical effects, in the equipment of this embodiment capable of depositing a refractory metal coating on the inner wall surface of a tubular workpiece, such as... Figures 1-9 As shown, several heaters 30 are fixed inside the coating chamber 1; the tubular workpiece 6 is positioned inside the heaters 30. The heaters 30 heat the tubular workpiece 6, and the lower part of the rotating cathode 10 extends into the tubular workpiece 6 to perform heating and coating simultaneously.

[0024] To achieve the aforementioned technical effects, in the equipment of this embodiment capable of depositing a refractory metal coating on the inner wall surface of a tubular workpiece, such as... Figures 1-9As shown, a vacuum pump assembly 7 is connected to one side of the coating chamber 1; a vacuum pump assembly 8 is fixedly connected below the vacuum pump assembly 7. The vacuum pump assembly 7 and the vacuum pump assembly 8 create a vacuum coating environment in the coating chamber 1.

[0025] To achieve the aforementioned technical effects, in the equipment of this embodiment capable of depositing a refractory metal coating on the inner wall surface of a tubular workpiece, such as... Figures 1-9 As shown, the coating chamber 1 is cylindrical, and several heaters 30 are evenly fixed inside the coating chamber 1 by a support frame 33.

[0026] To achieve the aforementioned technical effects, in the equipment of this embodiment capable of depositing a refractory metal coating on the inner wall surface of a tubular workpiece, such as... Figures 1-9 As shown, the rotating cathode 10 also includes: A cathode rotation drive component 40 is provided above the upper cover plate 2; A cathode 16 is driven and connected below the cathode rotation drive component 40, and the cathode 16 passes through the upper cover plate 2 into the tubular workpiece 6; the cathode rotation drive component 40 drives the cathode 16 to rotate in the tubular workpiece 6, thereby performing coating. The cathode rotation drive component 40 performs coating while driving the cathode 16 to rotate.

[0027] To achieve the aforementioned technical effects, in the equipment of this embodiment capable of depositing a refractory metal coating on the inner wall surface of a tubular workpiece, such as... Figures 1-9 As shown, the cathode rotation drive component 40 further includes: The housing of the cathode rotary motor 11 is fixed above the upper cover plate 2 by a fixing bracket; A cathode rotating drive wheel 12 is fixed on the motor shaft of the cathode rotating motor 11; the cathode rotating motor 11 drives the cathode rotating drive wheel 12 to rotate.

[0028] The outer shell of the cathode bearing housing is fixed above the upper cover plate 2; the cathode bearing housing 13 supports the cathode 16.

[0029] One end of the cathode 16 is fixedly connected in the bearing hole of the cathode bearing housing 13; the other end of the cathode 16 passes through the upper cover plate 2. Above the cathode bearing seat 13, a cathode rotating passive wheel 14 is fixedly connected to the cathode 16; the cathode rotating passive wheel 14 and the cathode rotating active wheel 12 constitute a driving structure.

[0030] A cathode rotating synchronous belt 15 is connected to the cathode rotating driving pulley 12 and the cathode rotating driven pulley 13; the cathode rotating motor 11 drives the cathode 16 to rotate through the cathode rotating synchronous belt 15. The cathode rotating synchronous belt 15 is used to connect and drive the cathode rotating driving pulley 12 and the cathode rotating driven pulley 13.

[0031] To achieve the aforementioned technical effects, in the equipment of this embodiment capable of depositing a refractory metal coating on the inner wall surface of a tubular workpiece, such as... Figures 1-9 As shown, the rotating cathode lifting device 4 is a first servo electric cylinder 41; the movable end of the first servo electric cylinder 41 is connected and fixed to the edge of the upper cover plate 2; the fixed end of the first servo electric cylinder 41 is fixedly connected to the top of the frame 21.

[0032] To achieve the aforementioned technical effects, in the equipment of this embodiment capable of depositing a refractory metal coating on the inner wall surface of a tubular workpiece, such as... Figures 1-9 As shown, the tubular workpiece lifting device 5 is a second servo electric cylinder 51; the movable end of the second servo electric cylinder 51 is connected and fixed to the edge of the lower cover plate 3; the fixed end of the second servo electric cylinder 51 is fixedly connected to the bottom of the frame 21.

[0033] To achieve the aforementioned technical effects, in the equipment of this embodiment capable of depositing a refractory metal coating on the inner wall surface of a tubular workpiece, such as... Figures 1-9 As shown, the tubular workpiece rotating device 20 also includes: The housing of the tubular workpiece rotary motor 22 is fixed below the lower cover plate 3; A tubular workpiece rotation drive wheel 23 is fixedly connected to the motor shaft of the tubular workpiece rotary motor 22; the tubular workpiece rotary motor 22 drives the tubular workpiece rotation drive wheel 23 to rotate.

[0034] The outer shell of the tubular workpiece bearing seat 24 is fixed above the lower cover plate 3; One end of the tubular workpiece spindle 25 is fixedly connected in the bearing hole of the tubular workpiece bearing seat 24; the other end of the tubular workpiece spindle 25 passes through the lower cover plate 3; the tubular workpiece bearing seat 24 is used to support the rotation of the tubular workpiece spindle 25.

[0035] Above the tubular workpiece bearing seat 24, a tubular workpiece rotating passive wheel 26 is fixedly connected to the tubular workpiece spindle 25; A synchronous belt 27 for rotating tubular workpiece is connected to the driving wheel 23 and the driven wheel 26 of the tubular workpiece rotation. The rotating motor 22 of the tubular workpiece drives the tubular workpiece 6 to rotate through the synchronous belt 27 of the tubular workpiece rotation. The driven wheel 26 and the synchronous belt 27 of the tubular workpiece rotation constitute a rotating structure for the tubular workpiece 6.

[0036] Above the lower cover plate 3, a tubular workpiece rotating plate 28 is movably connected to the tubular workpiece spindle 25 via a bearing; the tubular workpiece rotating plate 28 serves to connect and rotate.

[0037] The tubular workpiece drive rotation gear 29 is fixedly connected to the other end of the tubular workpiece spindle 25 above the tubular workpiece rotating plate 28. Several passive rotating gears 31 for rotating tubular workpieces are movably connected to the rotating plate 28 of the tubular workpieces via bearings; all of the passive rotating gears 31 for rotating tubular workpieces mesh with the active rotating gears 29 for rotating tubular workpieces; the passive rotating gears 31 for rotating tubular workpieces and the active rotating gears 29 for rotating tubular workpieces constitute a self-rotating structure.

[0038] A workpiece seat 32 is fixed above the passive rotating gear 31 of the tubular workpiece; the tubular workpiece 6 is fixed in the workpiece seat 32; the workpiece seat 32 is used to fix the tubular workpiece 6.

[0039] The tubular workpiece rotary motor 22 drives the tubular workpiece spindle 25 to rotate, which in turn drives the tubular workpiece active rotary gear 29 to drive the tubular workpiece passive rotary gear 31 to rotate, thus causing the tubular workpiece 6 to rotate.

[0040] To achieve the aforementioned technical effects, in the equipment of this embodiment capable of depositing a refractory metal coating on the inner wall surface of a tubular workpiece, such as... Figures 1-9 As shown, heater 30 also includes: Several layers of support frames 33 are fixed inside the coating chamber 1; the electromagnetic induction coil 34 is supported by the support frames 33. An electromagnetic induction coil 34 is fixed inside any one of the support frames 33; A heating coil 35 is fixed inside any one of the electromagnetic induction coils 34; the heating coil 35 is installed inside the electromagnetic induction coil 34 to form a heating structure.

[0041] Several electromagnetic induction coils 34 and several heating coils 35 are stacked together so that the central hole is on the same axis; the tubular workpiece 6 is placed inside the central hole.

[0042] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the present invention.

Claims

1. An apparatus for depositing a refractory metal coating on the inner wall surface of a tubular workpiece, characterized in that, include: Coating chamber; A top cover plate is provided above the coating chamber; A rotating cathode is provided above the upper cover plate; A rotating cathode lifting device is provided on both sides of the upper cover plate; The lower cover plate is disposed below the coating chamber; A tubular workpiece lifting device, wherein several tubular workpiece lifting devices are arranged on both sides of the lower cover plate; A tubular workpiece rotating device is provided above the lower cover plate; a tubular workpiece is fixed on the tubular workpiece rotating device. The rotating cathode lifting device and the tubular workpiece rotating device respectively drive several rotating cathodes and several tubular workpiece rotating devices to move up and down, so that the lower part of the rotating cathode is inserted into the tubular workpiece one by one for coating.

2. The equipment for coating refractory metals on the inner wall surface of a tubular workpiece according to claim 1, characterized in that, Several heaters are fixed in the coating chamber; the tubular workpiece is positioned inside the heaters, and the heaters heat the tubular workpiece, with the lower part of the rotating cathode extending into the tubular workpiece to perform heating and coating simultaneously.

3. The apparatus for depositing a refractory metal coating on the inner wall surface of a tubular workpiece according to claim 1, characterized in that, A vacuum pump assembly is fixedly connected to one side of the coating chamber and to the other side of the vacuum pump assembly.

4. The apparatus for depositing a refractory metal coating on the inner wall surface of a tubular workpiece according to claim 1, characterized in that, The coating chamber is cylindrical, and several heaters are evenly fixed inside the coating chamber by a support frame.

5. The apparatus for coating a refractory metal onto the inner wall surface of a tubular workpiece according to claim 1, characterized in that, The rotating cathode further includes: A cathode rotation drive component is disposed above the upper cover plate; Cathode; the cathode is driven and connected below the cathode rotation drive component, the cathode passes through the upper cover plate into the tubular workpiece; the cathode rotation drive component drives the cathode to rotate in the tubular workpiece.

6. The apparatus for depositing a refractory metal coating on the inner wall surface of a tubular workpiece according to claim 1, characterized in that, The cathode rotation drive component further includes: A cathode rotary motor, the outer casing of which is fixed above the upper cover plate by a fixing bracket; A cathode rotating drive wheel is fixed on the motor shaft of the cathode rotating motor; A cathode bearing housing, with the outer shell of the cathode bearing housing fixed above the upper cover plate; The cathode is fixedly connected at one end in the bearing hole of the cathode bearing housing; the other end of the cathode passes through the upper cover plate. A cathode rotating passive wheel is fixedly connected to the cathode above the cathode bearing seat; A cathode rotating synchronous belt is connected to the cathode rotating driving pulley and the cathode rotating driven pulley; the cathode rotating motor drives the cathode to rotate through the cathode rotating synchronous belt.

7. The apparatus for depositing a refractory metal coating on the inner wall surface of a tubular workpiece according to claim 1, characterized in that, The rotating cathode lifting device is a first servo electric cylinder; the movable end of the first servo electric cylinder is connected and fixed to the edge of the upper cover plate; the fixed end of the first servo electric cylinder is fixedly connected to the top of the frame.

8. The apparatus for depositing a refractory metal coating on the inner wall surface of a tubular workpiece according to claim 1, characterized in that, The tubular workpiece lifting device is a second servo electric cylinder; the movable end of the second servo electric cylinder is connected and fixed to the edge of the lower cover plate; the fixed end of the second servo electric cylinder is fixedly connected to the bottom of the frame.

9. The apparatus for depositing a refractory metal coating on the inner wall surface of a tubular workpiece according to claim 1, characterized in that, The aforementioned tubular workpiece rotating device further includes: A rotary motor for tubular workpieces, with the outer casing of the rotary motor fixed below the lower cover plate; A drive wheel for rotating the tubular workpiece is fixedly connected to the motor shaft of the motor for rotating the tubular workpiece. A tubular workpiece bearing housing, with the outer shell of the tubular workpiece bearing housing fixed above the lower cover plate; A tubular workpiece spindle is fixedly connected at one end in the bearing hole of the tubular workpiece bearing seat; the other end of the tubular workpiece spindle passes through the lower cover plate. A driven wheel for rotating a tubular workpiece is fixedly connected to the main shaft of the tubular workpiece above the bearing seat of the tubular workpiece. A synchronous belt for rotating the tubular workpiece is connected to the driving wheel and the driven wheel of the tubular workpiece; the motor for rotating the tubular workpiece drives the tubular workpiece to rotate via the synchronous belt. A tubular workpiece rotating plate is movably connected to the main shaft of the tubular workpiece via a bearing above the lower cover plate. A driving gear for rotating the tubular workpiece is fixedly connected to the other end of the main shaft of the tubular workpiece, above the rotating plate of the tubular workpiece. A passive rotating gear for rotating a tubular workpiece is movably connected to a rotating plate of the tubular workpiece via bearings; all of the passive rotating gears for rotating the tubular workpiece mesh with the active rotating gear for rotating the tubular workpiece. A workpiece holder is fixed above the passive rotating gear of the tubular workpiece; the tubular workpiece is fixed in the workpiece holder; The rotary motor drives the main shaft of the tubular workpiece to rotate, which in turn drives the active rotary gear of the tubular workpiece to rotate the passive rotary gear, causing the tubular workpiece to rotate.

10. The apparatus for depositing a refractory metal coating on the inner wall surface of a tubular workpiece according to claim 2, characterized in that, The heater further includes: A support frame, wherein several layers of the support frame are fixed inside the coating chamber; An electromagnetic induction coil is fixed inside any one of the support frames. A heating coil is fixed inside any one of the electromagnetic induction coils; Several electromagnetic induction coils and several heating coils are stacked together, such that the central hole is on the same axis; the tubular workpiece is disposed in the central hole.

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