Welding device for surfacing stainless steel sealing surface on cast iron valve base body

Abstract

The invention relates to the technical field of welding, in particular to a welding device for surfacing a stainless steel sealing surface on a cast iron valve base body, which comprises a positioner and a welding machine, a positioning and clamping device is rotatably arranged on the mounting surface of the positioner, and a rotation driving mechanism for driving the positioning and clamping device to rotate is arranged between the positioner and the positioning and clamping device; the positioning and clamping device comprises a clamping table, a positioning arm and a clamping arm, a first sliding block and a second sliding block are arranged on the clamping table in a sliding mode, the positioning arm is fixedly arranged on the first sliding block, and the clamping arm is fixedly arranged on the second sliding block. The driving gear ring drives the three racks to synchronously move, then the three positioning arms are driven to synchronously clamp the valve base body, the positioning arms synchronously move along the edges of the equilateral triangle all the time, so that the three positioning arms can achieve self-centering of the cast iron base body, the gear ring and the racks are standard components, the manufacturing difficulty is low, and the precision is better controlled.

Description

Technical Field

[0001] The invention relates to the technical field of welding, and more particularly to a welding device for surfacing a stainless steel sealing surface on a cast iron valve substrate. Background Art

[0002] With the development of industrial automation, the requirements for production efficiency and product quality in modern industrial production are getting higher and higher. The development of automation technology has prompted the traditional manual welding to gradually change to automated welding. In the valve manufacturing industry, especially the process of surfacing stainless steel sealing surface on cast iron valve substrate, which has high requirements for welding quality, more efficient and more precise welding equipment is needed.

[0003] The valve base needs to be rotated when the sealing surface is surfacing, so the valve base needs to be aligned. The existing positioning mechanism mostly uses a three-jaw chuck for centering and clamping. For valve bases with larger sizes, the manufacturing difficulty and cost of the three-jaw chuck are both relatively high. The three-jaw chuck is generally driven by a curved guide rail. As a non-conventional shape, the curved guide rail is difficult to process and the accuracy is not easy to guarantee.

[0004] The Chinese utility model patent with publication number CN207840552U discloses a manual multi-claw centering clamping structure for positioning welding of automobile parts, which drives the clamping arm to move synchronously toward the center of the disc by pushing the push clamp, thereby clamping and fixing the product, making the product axis coincide with the center of the disc, and ensuring the consistency of the axis of the welded product. Although this solution realizes the self-centering of the product, the disc and the positioning block cannot rotate, and cannot meet the welding requirements of the sealing surface on the valve base.

[0005] The Chinese invention patent with publication number CN118002968A discloses a valve body sealing surface welding device, which drives the clamping block to move by manually rotating the screw, and the clamping block drives the fixed ring to rotate through the magnetic element, so that the limit grooves provided on the fixed ring push the clamping rod to clamp the valve body. Due to the complex matching relationship between the clamping rod and the limit groove, in order to ensure the centering accuracy, the size and relative position of the three limit grooves are required to be high, resulting in high manufacturing costs.

[0006] Therefore, it is necessary to improve the prior art. Summary of the invention

[0007] In order to overcome the shortcomings in the prior art, a welding device for surfacing a stainless steel sealing surface on a cast iron valve substrate with high positioning accuracy and low cost is provided.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is: A welding device for surfacing a stainless steel sealing surface on a cast iron valve substrate, comprising a positioner and a welding machine, a positioning clamping device being rotatably arranged on the mounting surface of the positioner, and a rotating driving mechanism for driving the positioning clamping device to rotate being arranged between the positioner and the positioning clamping device; The positioning clamping device comprises a clamping platform, a positioning arm and a clamping arm. The three long sides of the clamping platform with an angle of 60° are provided with slide grooves. A first slider and a second slider are slidably arranged in each of the slide grooves. The positioning arm is fixedly arranged on the first slider, and the clamping arm is arranged on the second slider. A driving gear ring is rotatably provided at the lower side of the clamping platform, a rack meshing with the driving gear ring is fixedly connected to the first slider, a positioning sleeve hole is fixedly provided at the lower side of the clamping platform, a gear shaft is provided in the positioning sleeve hole, the middle part of the gear shaft meshes with the driving gear ring, a spline shaft is fixedly connected to the upper end of the gear shaft, a spline cavity matching with the spline shaft is provided in the positioning sleeve hole, and a compression spring is provided in the positioning sleeve hole to separate the spline shaft from the spline cavity; The lower end of the gear shaft is fixedly connected with a first thread nesting, the clamping table is fixedly provided with a positioning motor, the motor shaft of the positioning motor is provided with a second thread nesting matched with the first thread nesting, and the matching surfaces of the first thread nesting and the second thread nesting are inclined surfaces.

[0009] Preferably, the rotary drive mechanism comprises a drive motor, an inner gear ring is fixedly arranged inside the drive gear ring, the drive motor is fixedly arranged on the positioner, and a driving gear meshing with the inner gear ring is arranged on the motor shaft of the drive motor.

[0010] Preferably, a horizontal plane connected to the inclined plane is provided on the first thread nesting or the second thread nesting, and a torque sensor is connected to the motor shaft of the positioning motor. When the first thread nesting is disengaged from the second thread nesting, the torque sensor sends a signal to control the positioning motor to stop.

[0011] Preferably, the clamping arm comprises a rotating rod, an L-shaped sleeve and a pressing piece, the rotating rod is rotatably arranged on the second slider, the upper end of the rotating rod is provided with an external thread, the L-shaped sleeve is sleeved on the upper end of the rotating rod and cooperates with the rotating rod thread, the horizontal section of the L-shaped sleeve is slidably provided with a connecting rod, the pressing piece is arranged on the lower side of the connecting rod, and a rubber pad is arranged at the lower end of the pressing piece; A positioning rack is provided on the inner side of the slide groove, a positioning gear is fixedly connected to the lower end of the rotating rod, a rotating shaft is provided in the second sliding block for rotating along the vertical direction, a small gear meshing with the positioning rack is fixedly provided on the upper end of the rotating shaft, and a large gear meshing with the positioning gear is fixedly provided on the lower end of the rotating shaft.

[0012] Preferably, a locking groove is provided in the second sliding block, a locking rack is provided inside the sliding groove, a limiting rack cooperating with the locking rack is slidably provided in the locking groove, and a return spring is provided between the limiting rack and the locking groove; A connecting rod I is slidably arranged on the side of the limiting rack away from the engaging rack, and connecting rods II and III are hinged at both ends of the connecting rod I, and the ends of connecting rods II and III away from connecting rod I are hinged on the second sliding block, and a handle is fixedly connected to connecting rod II.

[0013] Preferably, it further comprises a welding machine seat and a welding machine frame, wherein the welding machine seat is located at one side of the positioner, the welding machine frame is arranged on the welding machine seat through a length adjustment mechanism and a height adjustment mechanism, and the welding machine is detachably arranged on the welding machine frame.

[0014] Preferably, the welding machine frame includes a mounting shaft and a mounting plate, the mounting plate is rotatably connected to the mounting shaft, and a positioning plate for vertically limiting the mounting plate is fixedly arranged on the mounting shaft; the welding machine is arranged at one end of the mounting plate, and a knocking assembly is arranged at the other end of the mounting plate; The positioning plate is provided with a positioning hole, the mounting plate is provided with a plug hole, and the positioning plate and the mounting plate are limited by a pin shaft.

[0015] Preferably, the knocking assembly includes a knocking hammer and a knocking motor, a sliding hole is provided at one end of the mounting plate, the knocking hammer is slidably arranged in the sliding hole, guide grooves are provided on both sides of the sliding hole, guide blocks that slide with the guide grooves are fixedly connected on both sides of the knocking hammer, and limit springs are provided between the upper and lower sides of the guide blocks and the ends of the guide grooves; The inner end of the sliding hole is rotatably provided with a cam matched with the bottom of the knocking hammer. The knocking motor is arranged on the mounting plate, and the motor shaft of the knocking motor is drivingly connected with the cam.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention drives the three racks to move synchronously by driving the gear ring, and then drives the three positioning arms to clamp the valve base synchronously. Since the positioning arms always move synchronously along the sides of the equilateral triangle, the three positioning arms can achieve self-centering of the cast iron base. The gear ring and rack are standard components, with low manufacturing difficulty and better precision control.

[0017] 2. The present invention transmits torque through the cooperation of the first thread nesting and the second thread nesting. When the positioning arm contacts the valve base, the torque between the first thread nesting and the second thread nesting increases, causing the first thread nesting to move upward and disconnect from the second thread nesting. At this time, the spline shaft is inserted into the spline cavity to lock the gear shaft and the drive gear ring, thereby achieving positioning and retention.

[0018] 3. The present invention uses a clamping arm to clamp the valve base. When the second slider moves along the slide groove, the small gear cooperates with the positioning rack to drive the rotating shaft to rotate, and then the large gear and the positioning gear cooperate to drive the rotating rod to rotate, so that the L-shaped sleeve and the clamping piece move downward to clamp the valve base. When the valve base is clamped, release the handle, and the limit rack presses the engaging rack under the action of the return spring to lock the second slider.

[0019] 4. The present invention provides a knocking assembly on the welding machine frame. After welding is completed, impurities at the weld can be removed by knocking the assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a structural schematic diagram of the positioning clamping device and the welding machine base of the present invention; Figure 3 This is a schematic diagram of the lower structure of the positioning and clamping device of the present invention; Figure 4 This is a schematic diagram of the internal structure of the positioning and clamping device of the present invention; Figure 5 It is a schematic diagram of the side structure of the positioning and clamping device of the present invention; Figure 6 for Figure 5 A partial enlarged view of middle A; Figure 7 This is a schematic diagram of the internal structure of the second sliding block of the present invention; Figure 8 It is a structural schematic diagram of the welding machine base of the present invention; Fig. 9 This is a schematic diagram of the internal structure of the positioning plate of the present invention; Fig.10 It is a cross-sectional view of the gear shaft of the present invention.

[0022] In the figure; 1-positioner, 2-welding machine, 3-positioning clamping device, 31-clamping table, 32-positioning arm, 33-torque sensor, 34-slide, 35-first slider, 36-second slider, 37-driving gear ring, 38-rack, 39-positioning sleeve hole, 310-gear shaft, 311-spline shaft, 312-spline cavity, 313-compression spring, 314-first tooth nesting, 315-positioning motor, 316-second tooth nesting, 317-horizontal plane, 4-rotation drive mechanism, 41-inner gear ring, 42-driving gear, 5-clamping arm, 51-rotating rod, 52-L-shaped sleeve, 53-pressing Parts, 54-connecting rod, 55-rubber pad, 56-positioning rack, 57-positioning gear, 58-rotating shaft, 59-locking groove, 510-limiting rack, 511-return spring, 512-connecting rod I, 513-connecting rod II, 514-connecting rod III, 515-handle, 516-engaging rack, 6-welding machine base, 61-welding machine frame, 62-length adjustment mechanism, 63-height adjustment mechanism, 64-mounting shaft, 65-mounting plate, 66-positioning plate, 67-pin shaft, 7-knocking assembly, 71-knocking hammer, 72-knocking motor, 73-guide groove, 74-guide block, 75-limiting spring, 76-cam. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example:

[0025] like Figures 1 to 10 As shown, a welding device for surfacing a stainless steel sealing surface on a cast iron valve substrate comprises a positioner 1 and a welder 2. A positioning clamping device 3 is rotatably provided on the mounting surface of the positioner 1. A rotary drive mechanism 4 for driving the positioning clamping device 3 to rotate is provided between the positioner 1 and the positioning clamping device 3. The positioner 1 can adopt the existing technology to change the angle of the surface to be welded so that the welding point is in a horizontal state as much as possible. The positioning clamping device 3 is used to position and clamp the valve substrate. Since the sealing surface of the valve substrate is a rotary surface, the rotary drive mechanism 4 drives the positioning clamping device 3 and the valve substrate thereon to rotate, so that the welder 2 can weld the entire sealing surface.

[0026] Specifically, the positioning and clamping device 3 includes a clamping platform 31, a positioning arm 32 and a clamping arm 5. The three long sides of the clamping platform 31 with an angle of 60° are all provided with a slide groove 34. A first slider 35 and a second slider 36 are slidably provided in each slide groove 34. The positioning arm 32 is fixedly provided on the first slider 35. The outer circumferential surface or the inner circumferential surface of the valve base is positioned by three synchronously moving positioning arms 32. The clamping arm 5 is provided on the second slider 36. The movement of the second slider 36 drives the clamping arm 5 to clamp the valve base.

[0027] In order to make the three first sliders 35 move synchronously, a driving ring gear 37 is rotatably provided on the lower side of the clamping table 31, and a rack 38 meshing with the driving ring gear 37 is fixedly connected to the first slider 35. When the driving ring gear 37 rotates, the three racks 38 are driven to move synchronously, thereby realizing synchronous control of the three first sliders 35.

[0028] A positioning sleeve hole 39 is fixedly provided at the lower side of the clamping platform 31, and a gear shaft 310 is provided in the positioning sleeve hole 39. The gear shaft 310 can rotate in the positioning sleeve hole 39 and can move up and down relative to the positioning sleeve hole 39. The middle part of the gear shaft 310 meshes with the driving gear ring 37, and a spline shaft 311 is fixedly connected to the upper end of the gear shaft 310. A spline cavity 312 matching with the spline shaft 311 is provided in the positioning sleeve hole 39, and a compression spring 313 is provided in the positioning sleeve hole 39 to separate the spline shaft 311 from the spline cavity 312. A first tooth nest 314 is fixedly connected to the lower end of the gear shaft 310, and a positioning motor 315 is fixedly provided on the clamping platform 31. A second tooth nest 316 matching with the first tooth nest 314 is provided on the motor shaft of the positioning motor 315, and the matching surfaces of the first tooth nest 314 and the second tooth nest 316 are inclined surfaces.

[0029] The second tooth nest 316 is driven to rotate by the positioning motor 315, and the first tooth nest 314 and the second tooth nest 316 cooperate to drive the gear shaft 310 to rotate, thereby driving the driving ring gear 37 to rotate; when the positioning arm 32 contacts the valve base, the movement resistance of the first slider 35 increases. At this time, the torque transmitted between the first tooth nest 314 and the second tooth nest 316 increases, so that the first tooth nest 314 overcomes the elastic force of the compression spring 313 and moves upward, driving the gear shaft 31 and the spline shaft 311 to move upward and insert into the spline cavity 312, thereby realizing circumferential limiting, and then locking the gear shaft 31 and the driving ring gear 37.

[0030] Preferably, a horizontal plane 317 connected to the inclined plane is provided on the first tooth nest 314 or the second tooth nest 316, and a torque sensor 33 is connected to the motor shaft of the positioning motor 315, and the torque sensor 33 adopts an existing sensor for measuring shaft torque. When the second tooth nest 316 is separated from the first tooth nest 314, the convex teeth of the second tooth nest 316 or the first tooth nest 314 abut against the corresponding horizontal plane 317, and at this time, the torque sensor 3 detects that the torque of the motor shaft suddenly decreases, and the torque sensor 33 sends a signal to control the positioning motor 315 to stop. Specifically, the positioning motor 315 is controlled by the motor drive board and the controller, and the torque sensor 33 sends a signal to the controller.

[0031] In order to drive the valve base to rotate as a whole, the rotation drive mechanism 4 includes a drive motor, an inner gear ring 41 is fixedly arranged inside the drive gear ring 37, the drive motor is fixedly arranged on the positioner 1, and a driving gear 42 meshing with the inner gear ring 41 is arranged on the motor shaft of the drive motor. After the drive gear ring 37 is locked with the clamping platform 31, the drive motor drives the driving gear 42 to rotate, and then drives the drive gear ring 37 and the clamping platform 31 to rotate through the inner gear ring 41.

[0032] In order to reliably clamp the valve base, the clamping arm 5 includes a rotating rod 51, an L-shaped sleeve 52 and a pressing member 53. The rotating rod 51 is rotatably arranged on the second slider 36. The upper end of the rotating rod 51 is provided with an external thread. The L-shaped sleeve 52 is sleeved on the upper end of the rotating rod 51 and is threadedly matched with the rotating rod 51. The height of the L-shaped sleeve 52 can be adjusted by rotating the rotating rod 51. The horizontal section of the L-shaped sleeve 52 is slidably provided with a connecting rod 54. The pressing member 53 is arranged on the lower side of the connecting rod 54. The lower end of the pressing member 53 is provided with a rubber pad 55.

[0033] A positioning rack 56 is provided inside the slide groove 34, a positioning gear 57 is fixedly connected to the lower end of the rotating rod 51, a rotating shaft 58 is provided in the second slider 36 for rotation in the vertical direction, a small gear meshing with the positioning rack 56 is fixedly provided on the upper end of the rotating shaft 58, and a large gear meshing with the positioning gear 57 is fixedly provided on the lower end of the rotating shaft 58. When in use, the second slider 36 is pulled to move along the slide groove 34, the small gear meshes with the positioning rack 56 to drive the rotating shaft 58 to rotate, and then the large gear meshes with the positioning gear 57 to drive the rotating rod 51 to rotate. The manual restriction clamp 53 does not cause horizontal displacement, and when the rotating rod 51 rotates, the L-shaped sleeve 52 is driven to descend, and the clamp 53 moves downward to clamp the valve base.

[0034] After the clamping member 53 presses the valve base, the position of the second slider 36 needs to be locked. Specifically, a locking groove 59 is provided in the second slider 36, and a locking rack 516 is provided on the inner side of the slide groove 34. A limiting rack 510 cooperating with the locking rack 516 is slidably provided in the locking groove 59, and a return spring 511 is provided between the limiting rack 510 and the locking groove 59. The return spring 511 presses the limiting rack 510 so that the limiting rack 510 meshes with the locking rack 516 to achieve locking.

[0035] A link rod I 512 is slidably provided on the side of the limit rack 510 away from the engaging rack 516, and two ends of the link rod I 512 are hingedly connected with a link rod II 513 and a link rod III 514 arranged in parallel, and one end of the link rod II 513 and the link rod III 514 away from the link rod I 512 is hingedly connected to the second slider 36, and the link rod II 513 or the link rod III 514 is fixedly connected to the handle 515. By pulling the handle 515, the limit rack 510 can be separated from the engaging rack 516.

[0036] In order to install the welding machine 2, a welding machine base 6 and a welding machine frame 61 are also included. The welding machine base 6 is located on one side of the positioner 1. The welding machine frame 61 is arranged on the welding machine base 6 through a length adjustment mechanism 62 and a height adjustment mechanism 63. The welding machine 2 is detachably arranged on the welding machine frame 61. The length adjustment mechanism 62 and the height adjustment mechanism 63 adopt the existing technology. For example, the length adjustment mechanism 62 and the height adjustment mechanism 63 both adopt a telescopic rod with adjustable length.

[0037] The welding machine frame 61 comprises a mounting shaft 64 and a mounting plate 65, wherein the mounting plate 65 is rotatably connected to the mounting shaft 64, the welding machine 2 is arranged at one end of the mounting plate 65, and the other end of the mounting plate 65 is provided with a knocking assembly 7. By rotating the mounting plate 65 by 180 degrees, the welding machine 2 and the knocking assembly 7 can be transformed.

[0038] In order to limit the mounting plate 65, a positioning plate 66 for vertically limiting the mounting plate 65 is fixedly provided on the mounting shaft 64; specifically, a positioning hole is provided on the positioning plate 66, and a plug hole is provided on the mounting plate 65, and the positioning plate 66 and the mounting plate 65 are limited by a pin shaft 67.

[0039] Preferably, the knocking assembly 7 includes a knocking hammer 71 and a knocking motor 72. A sliding hole is provided at one end of the mounting plate 65. The knocking hammer 71 is slidably arranged in the sliding hole. Guide grooves 73 are provided on both sides of the sliding hole. Guide blocks 74 that slide with the guide grooves 73 are fixedly connected on both sides of the knocking hammer 71. The travel of the knocking hammer 71 is limited by the guide blocks 74. Limiting springs 75 are provided between the upper and lower sides of the guide blocks 74 and the ends of the guide grooves 73.

[0040] The inner end of the sliding hole is rotatably provided with a cam 76 that cooperates with the bottom of the striking hammer 71 . The striking motor 72 is arranged on the mounting plate 65 . The motor shaft of the striking motor 72 is transmission-connected with the cam 76 , and the striking hammer 71 is excited by the cam 76 .

[0041] Only the preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention, and various changes should be included in the protection scope of the present invention.

Claims

1. A welding device for cladding a stainless steel sealing surface on a cast iron valve substrate, comprising a positioner (1) and a welding machine (2), characterized in that: A positioning clamping device (3) is rotatably arranged on the mounting surface of the positioner (1), and a rotation driving mechanism (4) for driving the positioning clamping device (3) to rotate is arranged between the positioner (1) and the positioning clamping device (3); The positioning clamping device (3) comprises a clamping platform (31), a positioning arm (32) and a clamping arm (5); three long sides of the clamping platform (31) forming an angle of 60° are each provided with a slide groove (34); a first slider (35) and a second slider (36) are slidably arranged in each of the slide grooves (34); the positioning arm (32) is fixedly arranged on the first slider (35); and the clamping arm (5) is arranged on the second slider (36). A driving gear ring (37) is rotatably provided on the lower side of the clamping platform (31); a rack (38) meshing with the driving gear ring (37) is fixedly connected to the first slider (35); a positioning sleeve hole (39) is fixedly provided on the lower side of the clamping platform (31); a gear shaft (310) is provided in the positioning sleeve hole (39); a middle portion of the gear shaft (310) meshes with the driving gear ring (37); a spline shaft (311) is fixedly connected to the upper end of the gear shaft (310); a spline cavity (312) matching with the spline shaft (311) is provided in the positioning sleeve hole (39); and a compression spring (313) for separating the spline shaft (311) from the spline cavity (312) is provided in the positioning sleeve hole (39); The lower end of the gear shaft (310) is fixedly connected to a first tooth nest (314); a positioning motor (315) is fixedly arranged on the clamping platform (31); a second tooth nest (316) matching with the first tooth nest (314) is arranged on the motor shaft of the positioning motor (315); and the matching surfaces of the first tooth nest (314) and the second tooth nest (316) are inclined surfaces.

2. The welding device for surfacing a stainless steel sealing surface on a cast iron valve substrate according to claim 1, characterized in that: The rotary drive mechanism (4) comprises a drive motor, an inner gear ring (41) is fixedly arranged inside the drive gear ring (37), the drive motor is fixedly arranged on the positioner (1), and a driving gear (42) meshing with the inner gear ring (41) is arranged on the motor shaft of the drive motor.

3. The welding device for surfacing a stainless steel sealing surface on a cast iron valve substrate according to claim 1, characterized in that: A horizontal surface (317) connected to the inclined surface is provided on the first tooth nest (314) or the second tooth nest (316); a motor shaft of the positioning motor (315) is connected to a torque sensor (33); when the first tooth nest (314) is disengaged from the second tooth nest (316), the torque sensor (33) sends a signal to control the positioning motor (315) to stop rotating.

4. The welding device for surfacing a stainless steel sealing surface on a cast iron valve substrate according to claim 1, characterized in that: The clamping arm (5) comprises a rotating rod (51), an L-shaped sleeve (52) and a pressing piece (53); the rotating rod (51) is rotatably arranged on the second slider (36); an upper end of the rotating rod (51) is provided with an external thread; the L-shaped sleeve (52) is sleeved on the upper end of the rotating rod (51) and is threadably engaged with the rotating rod (51); a connecting rod (54) is slidably arranged on the horizontal section of the L-shaped sleeve (52); the pressing piece (53) is arranged on the lower side of the connecting rod (54); and a rubber pad (55) is arranged at the lower end of the pressing piece (53); A positioning rack (56) is arranged inside the slide groove (34), a positioning gear (57) is fixedly connected to the lower end of the rotating rod (51), a rotating shaft (58) is arranged in the second sliding block (36) to rotate in the vertical direction, a small gear meshing with the positioning rack (56) is fixedly arranged at the upper end of the rotating shaft (58), and a large gear meshing with the positioning gear (57) is fixedly arranged at the lower end of the rotating shaft (58).

5. The welding device for surfacing a stainless steel sealing surface on a cast iron valve substrate according to claim 4, characterized in that: A locking groove (59) is provided in the second sliding block (36), a locking rack (516) is provided inside the sliding groove (34), a limiting rack (510) cooperating with the locking rack (516) is slidably provided in the locking groove (59), and a return spring (511) is provided between the limiting rack (510) and the locking groove (59); A connecting rod I (512) is slidably disposed on the side of the limiting rack (510) away from the engaging rack (516), and connecting rods II (513) and III (514) arranged in parallel are hinged at both ends of the connecting rod I (512), and ends of the connecting rods II (513) and III (514) away from the connecting rod I (512) are hinged on the second slider (36), and a handle (515) is fixedly connected to the connecting rod II (513).

6. The welding device for surfacing a stainless steel sealing surface on a cast iron valve substrate according to claim 1, characterized in that: It also comprises a welding machine base (6) and a welding machine frame (61), wherein the welding machine base (6) is located on one side of the positioner (1), the welding machine frame (61) is arranged on the welding machine base (6) via a length adjustment mechanism (62) and a height adjustment mechanism (63), and the welding machine (2) is detachably arranged on the welding machine frame (61).

7. A welding device for surfacing a stainless steel sealing surface on a cast iron valve substrate according to claim 6, characterized in that: The welding machine frame (61) comprises a mounting shaft (64) and a mounting plate (65), wherein the mounting plate (65) is rotatably connected to the mounting shaft (64), and a positioning plate (66) for vertically limiting the mounting plate (65) is fixedly arranged on the mounting shaft (64); the welding machine (2) is arranged at one end of the mounting plate (65), and a knocking assembly (7) is arranged at the other end of the mounting plate (65); The positioning plate (66) is provided with a positioning hole, the mounting plate (65) is provided with a plug hole, and the positioning plate (66) and the mounting plate (65) are limited by a pin shaft (67).

8. The welding device for surfacing a stainless steel sealing surface on a cast iron valve substrate according to claim 7, characterized in that: The knocking assembly (7) comprises a knocking hammer (71) and a knocking motor (72); a sliding hole is provided at one end of the mounting plate (65); the knocking hammer (71) is slidably arranged in the sliding hole; guide grooves (73) are provided on both sides of the sliding hole; guide blocks (74) slidably matched with the guide grooves (73) are fixedly connected to both sides of the knocking hammer (71); and limit springs (75) are provided between the upper and lower sides of the guide block (74) and the end of the guide groove (73); A cam (76) that cooperates with the bottom of the knocking hammer (71) is rotatably provided at the inner end of the sliding hole. The knocking motor (72) is arranged on the mounting plate (65), and the motor shaft of the knocking motor (72) is drivingly connected to the cam (76).

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