Nut projection welding machine for automobile body

Abstract

The invention relates to the technical field of welding equipment, and provides an automobile body nut projection welding machine which comprises a base, a first sliding block is slidably mounted at the top of the base, a second sliding block is slidably mounted at the top of the base, a workpiece is arranged at the top of the first sliding block, and a mounting hole is formed in the top of the workpiece. A clamping device is arranged on the inner wall of the first sliding block, an auxiliary device and a welding device are arranged above the workpiece, through the arrangement of the clamping device, a pressing plate moves to make contact with the workpiece so that the workpiece can be clamped, and when the clamping force is too large, the auxiliary device can be used for welding the workpiece. The pressing plate is stressed to move upwards to be matched with a round rod, a first spring, a limiting block, a second spring and a clamping groove, so that damage to the workpiece is reduced in the clamping process, and especially for workpieces with low hardness or complex shapes, deformation or breakage caused by improper clamping can be effectively prevented.

Description

Technical Field

[0001] The invention relates to the technical field of municipal roads, and in particular to a nut projection welding machine for an automobile body. Background Art

[0002] The projection welding machine for automobile body nuts is a device specially used in the automobile body manufacturing process to fix nuts to different parts of the body through resistance welding technology. This technology is essential to ensure the structural strength and durability of the automobile body. The projection welding technology can provide high-strength welds while maintaining the integrity of the threads, which is very important in the subsequent assembly process.

[0003] The patent with patent announcement number CN203282039U relates to the technical field of welding equipment. This patent provides a projection welding unit, including four projection welding machines, which are arranged relative to each other in a cross shape, and the tails of the four projection welding machines are relatively arranged with the tails facing inward and the heads facing outward; the tails of the four projection welding machines do not touch each other, so that a reserved space is formed between the tails of the four projection welding machines; a bridge for providing the public works required by the projection welding machine is provided above the projection welding machine. One end of the bridge is located above the center of the cross. The horizontal area of ​​the reserved space is 400mm*400mm. One end of the bridge is located 1200mm above the center of the cross. The public works required by the projection welding machine are water, electricity and gas. This patent uses a cross-shaped layout to layout the projection welding nut equipment for automobile body panels, which has the characteristics of cost saving, improved logistics, optimized working environment, and humanized work.

[0004] The above patents have the characteristics of cost saving, improved logistics, optimized working environment, and humanized work. However, the current measuring equipment has the following problems: improper clamping may cause scratches, dents or other forms of physical damage to the workpiece, which not only affects the appearance of the workpiece, but also may weaken its structural strength. Summary of the invention

[0005] The invention provides a nut projection welding machine for an automobile body, which solves the problem of a nut projection welding machine for an automobile body in the related art.

[0006] The technical solution of the present invention is as follows: A projection welding machine for nut of automobile body comprises a base, a sliding block 1 is slidably mounted on the top of the base, a sliding block 2 is slidably mounted on the top of the base, the workpiece is arranged on the top of the sliding block 1, a mounting hole is arranged on the top of the workpiece, a clamping device is arranged on the inner wall of the sliding block 1, and an auxiliary device and a welding device are arranged above the workpiece; wherein the clamping device comprises a fixing plate, a rotating motor, a rotating rod 1, a fixing button 1, a rotating rod 2, a brake rod, a fixing button 2, a supporting rod, a fixing frame, a screw rod, a sliding plate, a pressing plate, a round rod, a limiting block and a spring No. 1, wherein the The fixing plate is fixedly mounted on the top of the base, the fixing end of the rotating motor is fixedly mounted on the right side of the fixing plate, the rotating rod 1 is fixedly mounted on the output end of the rotating motor, the fixing button 1 is fixedly mounted on the left side of the rotating rod 1, the rotating rod 2 rotates and penetrates the inner and outer walls of the fixing plate, the rotating rod 2 is connected to the rotating rod 1 by a belt No. 1, the brake rod is fixedly mounted on the outer wall of the fixing button 1, and the workpiece is placed on the top of the sliding block 1 and the sliding block 2, the rotating motor rotates to drive the rotating rod 1 to rotate, the rotating rod 1 rotates to drive the fixing button 1 to rotate, and the fixing button 1 rotates to drive the brake rod to move The movement of the brake rod will contact the mounting hole of the workpiece, so that the workpiece moves forward, the fixing button 2 is fixedly installed on the left side of the rotating rod 2, the supporting rod is fixedly installed on the outer wall of the fixing button 2, the fixing frame is fixedly installed on the right side of the sliding block 2, the screw rod rotates and passes through the inner and outer walls of the fixing frame, the slide plate is slidably installed on the circumferential surface of the screw rod, the round rod is slidably installed and passes through the inner and outer walls of the slide plate, one side of the pressure plate is fixedly installed on the bottom of the round rod, and the other side of the pressure plate is slidably installed on the inner wall of the screw rod, the limit block is slidably installed on the surface of the slide plate, and the No. 1 spring is set between the pressure plate and the The workpiece is clamped between the slides. When the clamping force is too large, the pressure plate is forced to move upward, driving the round rod to move and compressing the No. 1 spring. The movement of the round rod will contact the inclined surface of the limit block, causing the limit block to move to the right and compressing the No. 2 spring. The movement of the limit block will be inserted into the slot of the fixed frame. At this time, the slide can not continue to move downward. When the slide moves upward, the inclined surface of the limit block contacts the inner wall of the slot, causing the limit block to move to the left and out of the slot. At this time, the limit block is reset by the No. 2 spring. At this time, the slide can move freely, which can reduce damage to the workpiece during the clamping process.

[0007] According to the above technical solution, a card slot is provided on the left side of the fixing frame, a spiral groove is provided on the circumferential surface of the screw rod, the spiral groove is threadedly connected to the slide plate, and the spiral groove is rotated by rotating the screw rod, and the rotation of the spiral groove causes the slide plate to move downward.

[0008] According to the above technical solution, a No. 2 spring is arranged between the slide plate and the limit block, the side of the limit block close to the round rod is set as an inclined surface, and the side of the limit block close to the slot is set as an inclined surface. When the round rod moves, it will contact the inclined surface of the limit block, causing the limit block to move to the right and compress the No. 2 spring at the same time. When the limit block moves, it will be inserted into the slot of the fixed frame. At this time, the slide plate cannot continue to move downward. When the slide plate moves upward, the inclined surface of the limit block contacts the inner wall of the slot, causing the limit block to move to the left and disengage from the slot.

[0009] According to the above technical solution, the auxiliary device includes a positioning groove, a concave disk, a limit button and a No. 3 spring. The positioning groove is fixedly installed on the inner wall of the screw rod, the concave disk is sleeved on the inner wall of the positioning groove, the limit button is rotatably installed on the inner wall of the concave disk, and the No. 3 spring is arranged between the limit button and the concave disk. When the positioning groove rotates, it will contact one side of the limit button so that the limit button rotates and compresses the No. 3 spring at the same time. At this time, the rotation of the screw rod will not be restricted by the limit button. When the screw rod reverses, it contacts the other side of the limit button through the positioning groove. At this time, the limit button restricts the positioning groove, and the screw rod cannot rotate.

[0010] According to the above technical solution, the auxiliary device also includes a button block, a gear and a rack rod. The button block is rotatably mounted on the inner wall of the concave disk, the gear is fixedly mounted on the circumferential surface of the button block, and the rack rod is fixedly mounted on the surface of the limit button close to the side of the No. 3 spring. The rack rod is meshed with the gear, and the gear is rotated by rotating the button block. The gear rotation drives the rack rod to move. The rack rod movement drives the limit button to rotate, so that the limit button is freed from the restriction of the positioning slot.

[0011] According to the above technical solution, the auxiliary device also includes an L-shaped frame, an electric push rod 1 and a welding groove. The L-shaped frame is fixedly installed on the top of the base, the fixed end of the electric push rod 1 is fixedly installed on the inner wall of the L-shaped frame, and the welding groove is fixedly installed on the output end of the electric push rod 1. The welding groove is driven to move by the downward movement of the output end of the electric push rod 1.

[0012] According to the above technical solution, the welding device includes a feeding rack, a stacking tube, a T-shaped rod and a rotating rack. The feeding rack is fixedly installed on the top of the base, the stacking tube is fixedly installed on the top of the feeding rack, the T-shaped rod is fixedly installed on the inner wall of the feeding rack, and the rotating rack is rotatably installed on the circumferential surface of the T-shaped rod. By placing a nut in the stacking tube, the nut is pushed along the feeding rack until it contacts the rotating rack through the output end of the electric push rod 2.

[0013] According to the above technical solution, the welding device also includes a receiving plate, a bump block, an electric push rod 2 and a nut. The receiving plate is fixedly installed on the top of the base, and the bump block slides through the inner and outer walls of the receiving plate. A No. 4 spring is arranged between the bump block and the receiving plate. The fixed end of the electric push rod 2 is fixedly installed on the inner wall of the feeding rack. The nut is arranged on the inner wall of the stacking tube. At this time, the welding groove moves to contact the nut, so that the rotating frame is rotated under force. At this time, the welding groove is fitted with the nut and then moves to fit with the bump block for welding.

[0014] The working principle and beneficial effects of the present invention are: 1. In the present invention, through the setting of the clamping device, the workpiece is placed on the top of the sliding block 1 and the sliding block 2, and the brake rod moves to contact the mounting hole of the workpiece to move the workpiece forward, and the support rod moves to contact the bottom of the workpiece so that the bottom of the workpiece is supported, and the workpiece is clamped by the movement of the pressure plate to contact the workpiece. When the clamping force is too large, the pressure plate is forced to move upward to cooperate with the round rod, the No. 1 spring, the limit block, the No. 2 spring and the slot to prevent damage to the workpiece during the clamping process, especially for workpieces with lower hardness or complex shapes, it can effectively prevent deformation or cracking caused by improper clamping. After clamping is completed, the brake rod contacts the mounting hole to drive the workpiece to move equidistantly. At this time, the workpiece will drive the sliding block 1 and the sliding block 2 to move, so that the workpiece can be clamped and moved all the time.

[0015] 2. In the present invention, by setting up the auxiliary device, the rotation of the screw rod drives the locking groove to rotate, and the limit button and the No. 3 spring restrict the screw rod from rotating, so as to prevent the screw rod from being accidentally touched by external force and causing reversal after the adjustment is completed, which will cause adjustment errors and affect the clamping effect.

[0016] 3. In the present invention, by setting up the welding device, by placing the nut in the stacking tube, the electric push rod 2 cooperates with the nut, the feeding rack, the rotating rack, the welding groove and the bump to perform welding, the workpiece moves to contact the bump block so that the bump block moves downward until the next mounting hole and the bump block are on the same horizontal line, and the bump block is reset by the No. 4 spring, so that the mounting hole here is welded, and the consistency between the welding points can be ensured by equidistant movement, avoiding errors caused by manual operation, thereby improving the overall quality of welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a schematic diagram of the structure of the feeding rack and the sliding block in two positions of the present invention; Figure 3 This is a schematic diagram of the position structure of the brake rod and the support rod of the present invention; Figure 4 For the present invention Figure 3 A schematic diagram of the structure enlargement of part A; Figure 5 This is a schematic diagram of the position structure of the screw rod and the positioning groove of the present invention; Figure 6 For the present invention Figure 5 A schematic diagram of the structure of part B in the middle is enlarged; Figure 7 It is a schematic diagram of the position structure of the T-shaped rod and the rotating frame of the present invention.

[0019] In the figure: 1. base; 2. sliding block 1; 3. sliding block 2; 4. workpiece; 10. fixed plate; 11. rotating motor; 12. rotating rod 1; 13. fixing button 1; 131. rotating rod 2; 14. brake rod; 15. fixing button 2; 16. support rod; 17. fixed frame; 18. screw rod; 19. slide plate; 110. pressure plate; 111. round rod; 112. limit block; 113. spring No. 1; 20. positioning groove; 21. concave plate; 22. limit button; 23. spring No. 3; 24. button block; 25. gear; 26. rack rod; 27. L-shaped frame; 28. electric push rod 1; 29. ​​welding groove; 30. feeding frame; 31. stacking tube; 32. T-shaped rod; 33. rotating frame; 34. receiving plate; 35. bump block; 36. electric push rod 2; 37. nut. DETAILED DESCRIPTION

[0020] The following will be combined with 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 making creative work are within the scope of protection of the present invention.

[0021] Example 1 like Figure 1 to Figure 7As shown, this embodiment proposes a nut projection welding machine for a car body, including a base 1, a sliding block 2 is slidably installed on the top of the base 1, a sliding block 3 is slidably installed on the top of the base 1, a workpiece 4 is arranged on the top of the sliding block 2, a mounting hole is arranged on the top of the workpiece 4, and a clamping device is arranged on the inner wall of the sliding block 2, and the clamping device includes a fixing plate 10, a rotating motor 11, a rotating rod 12, a fixing button 13, a rotating rod 21, a brake rod 14, a fixing button 215, a support rod 16, a fixing frame 17, a thread Rod 18, slide plate 19, pressure plate 110, round rod 111, limit block 112 and spring No. 113, fixed plate 10 is fixedly mounted on the top of base 1, the fixed end of rotating motor 11 is fixedly mounted on the right side of fixed plate 10, rotating rod 12 is fixedly mounted on the output end of rotating motor 11, fixed button 13 is fixedly mounted on the left side of rotating rod 12, rotating rod 2 131 rotates through the inner and outer walls of fixed plate 10, rotating rod 2 131 is connected to rotating rod 12 through belt No. 1, brake rod 14 is fixedly mounted on fixed button The outer wall of the first 13, the fixing button 15 is fixedly installed on the left side of the rotating rod 131, the supporting rod 16 is fixedly installed on the outer wall of the fixing button 15, and the brake rod 14 moves to contact the mounting hole of the workpiece 4 so that the workpiece 4 moves forward, and the supporting rod 16 moves to contact the bottom of the workpiece 4 so that the bottom of the workpiece 4 is supported, the fixing frame 17 is fixedly installed on the right side of the sliding block 23, the screw rod 18 rotates to pass through the inner and outer walls of the fixing frame 17, the slide plate 19 is slidably installed on the circumferential surface of the screw rod 18, the round rod 111 is slidably installed to pass through the inner and outer walls of the slide plate 19, one side of the pressing plate 110 is fixedly installed on the bottom of the round rod 111, and the other side of the pressing plate 110 is slidably installed on the inner wall of the screw rod 18, and the limit block 112 is slidably installed on the surface of the slide plate 19 to prevent damage to the workpiece 4 during the clamping process, especially for the workpiece 4 with lower hardness or complex shape, which can effectively prevent deformation or rupture caused by improper clamping, and the No. 1 spring 113 is arranged between the pressing plate 110 and the slide plate 19, and the pressing plate 110 is driven to reset by the arranged No. 1 spring 113.

[0022] A clamping groove is arranged on the left side of the fixing frame 17 , and a spiral groove is arranged on the circumferential surface of the screw rod 18 . The spiral groove is threadedly connected with the slide plate 19 , and the slide plate 19 is rotated to move downward.

[0023] A No. 2 spring is arranged between the slide plate 19 and the limit block 112, and the No. 2 spring drives the limit block 112 to reset. The side of the limit block 112 close to the round rod 111 is set as an inclined surface, and the side of the limit block 112 close to the slot is set as an inclined surface. The inclined surface of the limit block 112 contacts the inner wall of the slot, so that the limit block 112 moves to the left and leaves the slot.

[0024] When the present embodiment is working, the workpiece 4 is placed on the top of the sliding block 1 2 and the sliding block 2 3, and the rotating motor 11 rotates to drive the rotating rod 1 12 to rotate, and the rotating rod 1 12 rotates to drive the fixing button 13 to rotate, and the fixing button 13 rotates to drive the brake rod 14 to move, and the brake rod 14 moves to contact with the mounting hole of the workpiece 4, so that the workpiece 4 moves forward, and at the same time, the rotating rod 12 rotates to drive the rotating rod 2 131 to rotate by means of the No. 1 belt, and the rotating rod 2 131 rotates to drive the fixing button 2 15 to move, and the fixing button 2 15 moves to drive the support rod 16 to move, and the support rod 16 moves to contact with the bottom of the workpiece 4, so that the bottom of the workpiece 4 is supported, and the spiral groove is driven to rotate by the rotating screw 18, and the rotation of the spiral groove causes the slide plate 19 to move downward, and the movement of the slide plate 19 drives the round rod 111 to move, and the movement of the round rod 111 drives the pressure plate 110 to move, and the pressure plate 110 moves to contact with the workpiece 4, so that the workpiece 4 is clamped. When the clamping force is too great, the pressure plate 110 is forced to move upward, driving the round rod 111 to move and compressing the No. 1 spring 113. The movement of the round rod 111 will contact the inclined surface of the limit block 112, causing the limit block 112 to move to the right and compress the No. 2 spring. The movement of the limit block 112 will be inserted into the slot of the fixed frame 17, and the slide plate 19 cannot continue to move downward. When the slide plate 19 moves upward, the inclined surface of the limit block 112 contacts the inner wall of the slot, causing the limit block 112 to move to the left and out of the slot. At this time, the limit block 112 is reset by the No. 2 spring. At this time, the slide plate 19 can move freely, which can reduce damage to the workpiece 4 during the clamping process, especially for the workpiece 4 with lower hardness or complex shape. It can effectively prevent deformation or cracking caused by improper clamping. After clamping is completed, the brake rod 14 contacts the mounting hole to drive the workpiece 4 to move equidistantly. At this time, the workpiece 4 will drive the sliding block 1 2 and the sliding block 2 3 to move.

[0025] Example 2 like Figure 1 to Figure 7 As shown, based on the same concept as the above-mentioned embodiment 1, this embodiment further proposes: an auxiliary device and a welding device are arranged above the workpiece 4, the auxiliary device includes a positioning groove 20, a concave disk 21, a limit button 22 and a No. 3 spring 23, the positioning groove 20 is fixedly installed on the inner wall of the screw rod 18, the concave disk 21 is sleeved on the inner wall of the positioning groove 20, and the limit button 22 is rotatably installed on the inner wall of the concave disk 21 to prevent the screw rod 18 from being accidentally touched by external force and causing reversal after the adjustment is completed, which will cause adjustment errors and affect the clamping effect, and the No. 3 spring 23 is arranged between the limit button 22 and the concave disk 21, and the limit button 22 is reset by the arranged No. 3 spring 23.

[0026] The auxiliary device also includes a button block 24, a gear 25 and a rack rod 26. The button block 24 is rotatably mounted on the inner wall of the concave disk 21, the gear 25 is fixedly mounted on the circumferential surface of the button block 24, and the rack rod 26 is fixedly mounted on the surface of the limit button 22 close to the side of the No. 3 spring 23. The rack rod 26 is meshed with the gear 25, so that the limit button 22 is free from the restriction of the locking groove 20, and the screw rod 18 can be rotated freely at this time.

[0027] The auxiliary device also includes an L-shaped frame 27, an electric push rod 28 and a welding groove 29. The L-shaped frame 27 is fixedly installed on the top of the base 1, the fixed end of the electric push rod 28 is fixedly installed on the inner wall of the L-shaped frame 27, and the welding groove 29 is fixedly installed on the output end of the electric push rod 28. The welding groove 29 is driven to move by the downward movement of the output end of the electric push rod 28.

[0028] The welding device includes a feed rack 30, a stacking tube 31, a T-shaped rod 32 and a rotating rack 33. The feed rack 30 is fixedly installed on the top of the base 1, the stacking tube 31 is fixedly installed on the top of the feed rack 30, the T-shaped rod 32 is fixedly installed on the inner wall of the feed rack 30, and the rotating rack 33 is rotatably installed on the circumferential surface of the T-shaped rod 32. After the welding groove 29 is fitted with the nut 37, it is moved to fit with the bump block 35 for welding.

[0029] The welding device also includes a receiving plate 34, a bump block 35, an electric push rod 2 36 and a nut 37. The receiving plate 34 is fixedly installed on the top of the base 1. The bump block 35 slides through the inner and outer walls of the receiving plate 34. A No. 4 spring is arranged between the bump block 35 and the receiving plate 34. The bump block 25 is reset by the arranged No. 4 spring. The fixed end of the electric push rod 2 36 is fixedly installed on the inner wall of the feeding rack 30, and the nut 37 is arranged on the inner wall of the stacking tube 31.

[0030] When the screw rod 18 is in operation, the locking groove 20 is driven to rotate by the rotation of the screw rod 18. When the locking groove 20 rotates, it contacts one side of the limit button 22, causing the limit button 22 to rotate and compress the No. 3 spring 23. At this time, the rotation of the screw rod 18 will not be restricted by the limit button 22. When the screw rod 18 is reversed, the locking groove 20 contacts the other side of the limit button 22. At this time, the limit button 22 restricts the locking groove 20. At this time, the screw rod 18 cannot rotate, preventing the screw rod 18 from being accidentally touched by external force after the adjustment is completed, causing the adjustment to fail, thereby affecting the clamping effect. When the screw rod 18 needs to be reversed, the gear 25 is driven to rotate by rotating the button block 24, and the gear 25 rotates to drive the rack rod 26 to move. The rack rod 26 moves to drive the limit button 22 to rotate, so that the limit button 22 is free from the restriction of the locking groove 20. At this time, the screw rod 18 can be freely rotated, and the welding groove 29 is driven to move by the output end of the electric push rod 1 28 moving downward; By placing the nut 37 in the stacking tube 31, the nut 37 is pushed by the output end of the electric push rod 2 36 to move along the feeding rack 30 until it contacts the rotating rack 33. At this time, the welding groove 29 moves to contact the nut 37, so that the rotating rack 33 is forced to rotate. At this time, the welding groove 29 fits with the nut 37 and moves to fit with the bump block 35 for welding. The workpiece 4 moves to contact the bump block 35, causing the bump block 35 to move downward until the next mounting hole and the bump block 35 are on the same horizontal line. The bump block 35 is reset by the No. 4 spring, thereby welding the mounting hole here.

[0031] The above are only preferred embodiments of the present invention and are 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 in the protection scope of the present invention.

Claims

1. A projection welding machine for nuts of automobile bodies, comprising a base (1), Features: A sliding block 1 (2) is slidably mounted on the top of the base (1), a sliding block 2 (3) is slidably mounted on the top of the base (1), the workpiece (4) is arranged on the top of the sliding block 1 (2), a mounting hole is arranged on the top of the workpiece (4), a clamping device is arranged on the inner wall of the sliding block 1 (2), and an auxiliary device and a welding device are arranged above the workpiece (4); The clamping device comprises a fixing plate (10), a rotating motor (11), a rotating rod (12), a fixing button (13), a rotating rod (131), a braking rod (14), a fixing button (15), a supporting rod (16), a fixing frame (17), a screw rod (18), a sliding plate (19), a pressing plate (110), a round rod (111), a limiting block (112) and a first spring (113), wherein the fixing plate (10) is fixedly mounted on the top of the base (1), the fixing end of the rotating motor (11) is fixedly mounted on the right side of the fixing plate (10), and the rotating rod (12) is fixedly mounted on the rotating motor (11). The output end of the fixing button 1 (13) is fixedly mounted on the left side of the rotating rod 1 (12), the rotating rod 2 (131) rotates and penetrates the inner and outer walls of the fixing plate (10), the rotating rod 2 (131) is transmission-connected with the rotating rod 1 (12) via a No. 1 belt, the braking rod (14) is fixedly mounted on the outer wall of the fixing button 1 (13), the fixing button 2 (15) is fixedly mounted on the left side of the rotating rod 2 (131), the supporting rod (16) is fixedly mounted on the outer wall of the fixing button 2 (15), the fixing frame (17) is fixedly mounted on the right side of the sliding block 2 (3), and the screw rod (18) rotates and penetrates the inner and outer walls of the fixing frame (17).

2. A projection welding machine for nuts of automobile bodies according to claim 1, Features: The slide plate (19) is slidably mounted on the circumferential surface of the screw rod (18); the round rod (111) is slidably mounted and penetrates the inner and outer walls of the slide plate (19); one side of the pressure plate (110) is fixedly mounted on the bottom of the round rod (111); the other side of the pressure plate (110) is slidably mounted on the inner wall of the screw rod (18); the limit block (112) is slidably mounted on the surface of the slide plate (19); and the first spring (113) is arranged between the pressure plate (110) and the slide plate (19).

3. A projection welding machine for nut of automobile body according to claim 2, Features: A clamping groove is provided on the left side of the fixing frame (17), and a spiral groove is provided on the circumferential surface of the screw rod (18), wherein the spiral groove is threadedly connected to the slide plate (19).

4. A projection welding machine for nut of automobile body according to claim 3, Features: A No. 2 spring is provided between the slide plate (19) and the limit block (112); a side of the limit block (112) close to the round rod (111) is provided as an inclined surface; and a side of the limit block (112) close to the slot is provided as an inclined surface.

5. A projection welding machine for nut of automobile body according to claim 4, Features: The auxiliary device comprises a locking groove (20), a concave plate (21), a limit button (22) and a No. 3 spring (23); the locking groove (20) is fixedly mounted on the inner wall of the screw rod (18); the concave plate (21) is sleeved on the inner wall of the locking groove (20); the limit button (22) is rotatably mounted on the inner wall of the concave plate (21); and the No. 3 spring (23) is arranged between the limit button (22) and the concave plate (21).

6. A projection welding machine for nuts of automobile bodies according to claim 5, Features: The auxiliary device further comprises a button block (24), a gear (25) and a rack rod (26); the button block (24) is rotatably mounted on the inner wall of the concave disk (21); the gear (25) is fixedly mounted on the circumferential surface of the button block (24); the rack rod (26) is fixedly mounted on the surface of the limit button (22) on a side close to the third spring (23); and the rack rod (26) is meshed with the gear (25).

7. A projection welding machine for nuts of automobile bodies according to claim 6, Features: The auxiliary device further comprises an L-shaped frame (27), an electric push rod (28) and a welding groove (29), wherein the L-shaped frame (27) is fixedly mounted on the top of the base (1), the fixed end of the electric push rod (28) is fixedly mounted on the inner wall of the L-shaped frame (27), and the welding groove (29) is fixedly mounted on the output end of the electric push rod (28).

8. A projection welding machine for nuts of automobile bodies according to claim 7, Features: The welding device comprises a feeding rack (30), a stacking tube (31), a T-shaped rod (32) and a rotating rack (33); the feeding rack (30) is fixedly mounted on the top of the base (1); the stacking tube (31) is fixedly mounted on the top of the feeding rack (30); the T-shaped rod (32) is fixedly mounted on the inner wall of the feeding rack (30); and the rotating rack (33) is rotatably mounted on the circumferential surface of the T-shaped rod (32).

9. A projection welding machine for nuts of automobile bodies according to claim 8, Features: The welding device further comprises a receiving plate (34), a convex block (35), a second electric push rod (36) and a nut (37); the receiving plate (34) is fixedly mounted on the top of the base (1); and the convex block (35) slides through the inner and outer walls of the receiving plate (34).

10. A projection welding machine for nuts of automobile bodies according to claim 9, Features: A No. 4 spring is provided between the convex block (35) and the receiving plate (34); the fixed end of the second electric push rod (36) is fixedly mounted on the inner wall of the feeding frame (30); and the nut (37) is provided on the inner wall of the stacking tube (31).

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