Multi-process continuous reaming device

Abstract

The multi-process continuous reaming device comprises a flat hammer anvil, a blank, a hammer head and a horse rod, two connecting blocks are integrally and fixedly connected to the two sides of the flat hammer anvil, a rotating shaft column is movably connected to the two connecting blocks on the same side in an inserted mode, and a connecting plate with the L-shaped longitudinal section is fixedly connected to the periphery of the middle of the rotating shaft column; the L-shaped bent part, away from the rotating shaft column, of the connecting plate faces the flat hammer anvil, and the tail end of the L-shaped bent part is fixedly connected with a mandrel supporter piece. Compared with the prior art, a flat hammer anvil is replaced with a trestle hammer anvil, so that continuous upsetting, punching and chambering operations of workpieces are realized; after upsetting and punching operation, a structural form similar to a mandrel supporter hammer anvil can be formed only by pulling the mandrel supporter pieces on the two sides of the flat hammer anvil, subsequent reaming operation can be achieved, the operation of pulling the mandrel supporter pieces to form the structural form similar to the mandrel supporter hammer anvil is simple, time and labor are saved, and therefore the overall machining efficiency is greatly improved, and the machining cost is reduced. Therefore, continuous operation is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of forging tooling, and in particular relates to a multi-process continuous hole expanding device. Background Art

[0002] Forging is a processing method that uses a forging machine to apply pressure to a metal blank to cause it to undergo plastic deformation in order to obtain a forging with certain mechanical properties, shape, and size.

[0003] Among them, when forging annular products, there are three stages: upsetting, punching and expanding. The traditional flat hammer anvil is a flat type, as shown in the attached Figure 1 The flat hammer anvil shown in the figure first places the cylindrical blank on the center of the flat hammer anvil, and then the hammer head presses down on the blank to achieve the initial upsetting of the blank. After upsetting, the punching column core extends from the center of the hammer head to punch the upsetting blank. After the blank is punched, the punched blank needs to be placed on the horse stick, and then the horse stick is placed as shown in the attached figure. Figure 2 The next step of hole enlarging can only be carried out on the horse-frame hammer anvil shown in the figure. However, it takes more than an hour to disassemble and assemble the flat hammer anvil to replace the horse-frame hammer anvil in the prior art, which is very time-consuming and labor-intensive, greatly affecting the overall processing efficiency. Summary of the invention

[0004] The present invention aims at solving the problems in the prior art and proposes the following technical solutions: A multi-process continuous hole reaming device, comprising a flat hammer anvil, a blank, a hammer head and a horse stick, two connecting blocks are integrally fixedly connected to the two sides of the flat hammer anvil, a rotating shaft column is movably inserted into the two connecting blocks on the same side, a connecting plate with an L-shaped longitudinal section is fixedly connected to the periphery of the middle part of the rotating shaft column, the L-shaped bending part of the connecting plate away from the rotating shaft column faces the flat hammer anvil, and a horse frame is fixedly connected to the end of the L-shaped bending part; During the upsetting and punching stages of the blank, the blank is placed in the center of the top of the flat hammer anvil, and the two horse frames are detached from the top of the flat hammer anvil and placed in an "eight" shape; after the blank is upset and punched, the horse frames are manually turned to rotate around the rotating shaft column until the horse frames stand vertically on the top of the flat hammer anvil, and the bottom of the vertically standing horse frames and the top of the flat hammer anvil are in contact, and a horse bar groove is opened on the top of the horse frames; after the punching of the blank, the horse bars are sleeved around the periphery of the center part of the horse bars and the horse bar horizontal placement frame is placed in the horse bar grooves on the tops of the two horse frames, and the hammer head acts on the punched blank to realize the subsequent hole expansion stage.

[0005] As a preferred embodiment of the above technical solution, a through groove is provided in the middle of the connecting block, and the top of the through groove passes through the top of the connecting block so that the longitudinal section of the connecting block is "U"-shaped.

[0006] As a preferred embodiment of the above technical solution, the periphery of the rotating shaft column is processed with symmetrically arranged cutting surfaces, and the distance between the two symmetrically arranged cutting surfaces is smaller than the diameter of the rotating shaft column; the connecting plate is fixedly connected to the periphery of the middle part and is located in the middle position of the two cutting surfaces; The through groove comprises an upper through groove, an arc through groove and a lower through groove which are arranged in sequence from top to bottom. The diameter of the arc through groove is larger than the diameter of the shaft column. The widths of the upper through groove and the lower through groove match the spacing between two symmetrically arranged cutting surfaces.

[0007] As a preferred embodiment of the above technical solution, the height of the lower through groove is h1, and when the rotating shaft column and the arc through groove are coaxial, the rotating shaft column is rotated until the bottom of the horse frame and the top of the hammer anvil are parallel. At this time, the distance between the bottom of the horse frame and the top of the hammer anvil is h2, and h1>h2.

[0008] As a preferred embodiment of the above technical solution, both ends of the cutting surface are fixedly connected with limiting protrusions.

[0009] As a preferred embodiment of the above technical solution, the two limiting protrusions located on the same cutting surface are both located outside the two connecting blocks, and the distance between the two limiting protrusions is d, the distance between the two connecting blocks on the sides away from each other is d1, and d>d1.

[0010] As a preferred embodiment of the above technical solution, the distance between the end of the limiting protrusion away from the cutting surface and the cutting surface is q, and when the shaft column and the arc groove are coaxial, the distance between the outer periphery of the shaft column and the inner wall of the arc groove is q1, and q>2q1.

[0011] As a preferred embodiment of the above technical solution, a horizontal groove is provided on the side of the two connecting blocks away from each other, a limit baffle matching the horizontal groove is movably inserted in the horizontal groove, and the limit baffle is located above the circular arc groove.

[0012] As a preferred embodiment of the above technical solution, the middle part of the limit baffle is processed into an arc shape, and the curvature of the arc shape matches the curvature of the outer circumference of the shaft column. When the shaft column and the arc groove are coaxial, the outer circumferential arc surface of the shaft column and the arc-shaped middle part of the limit baffle are in contact with each other.

[0013] As a preferred embodiment of the above technical solution, a limiting strip is fixedly connected to the connecting plate, a limiting groove is provided on the top of the connecting block, and the limiting groove matches the limiting strip.

[0014] As a preferred embodiment of the above technical solution, when the two horse rack members stand vertically on the top of the flat hammer anvil, the distance between the two horse rack members is greater than twice the width of the hammer head.

[0015] As a preferred embodiment of the above technical solution, the bottom of the longitudinal section of the horse frame member is conical, and the bottom area of ​​the horse frame member is larger than the top area of ​​the horse frame member.

[0016] As a preferred embodiment of the above technical solution, an anti-slip groove with a diameter larger than that of the horse stick groove is opened in the middle of the horse stick groove, and fixing rings are provided on both ends of the horse stick, and the diameter of the fixing rings matches the anti-slip groove.

[0017] As a preferred embodiment of the above technical solution, the diameter of the fixing ring is smaller than the inner diameter of the punching hole of the blank.

[0018] The beneficial effects of the present invention are: When the continuous hole expanding device of the present invention is working, the blank is first placed on the center of the top of the flat hammer anvil, and the two horse racks are simultaneously moved to rotate around the rotating shaft column, so that the horse racks are separated from the top of the flat hammer anvil and placed in an "eight" shape, that is, Figure 3 The hammer head then performs upsetting and punching operations on the blank; after the blank is upset and punched, the horse frame is manually moved to rotate around the rotating shaft column until the horse frame stands vertically on the top of the flat hammer anvil, that is, Fig. 9 In the state shown, the bottom of the vertically standing horse frame and the top of the flat hammer anvil are in contact, and a horse rod groove is provided on the top of the horse frame; after the punching, the blank is sleeved around the central part of the horse rod and the horizontal horse rod placement frame is placed in the horse rod groove on the top of the two horse frame pieces, and the hammer head acts on the punched blank to realize the subsequent hole expansion stage. Compared with the prior art in which the flat hammer anvil is replaced with a horse frame hammer anvil to realize continuous upsetting, punching, and hole expansion of the workpiece; the present invention can form a structure similar to the horse frame hammer anvil by only moving the horse frame pieces on both sides of the flat hammer anvil after the upsetting and punching operations, and then the subsequent hole expansion operation can be carried out. Since the operation of moving the horse frame pieces to form a structure similar to the horse frame hammer anvil is simple, time-saving and labor-saving, it greatly improves the overall processing efficiency, thereby realizing continuous operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 What is shown is a schematic diagram of the structure of a flat hammer anvil in the prior art; Figure 2 What is shown is a structural schematic diagram of a horse rack hammer anvil in the prior art; Figure 3 The figure shows a three-dimensional structural schematic diagram of a multi-step continuous hole expanding device in the present invention at the upsetting and hole opening stages; Figure 4 The figure shows the structure schematic diagram of the rotating shaft column and the horse frame member in the upsetting and hole-opening stages of a multi-process continuous hole-expanding device in the present invention; Figure 5 The figure shows a three-dimensional structural diagram of a multi-step continuous hole-expanding device in the present invention during the process of adjusting the position of the horse frame in the hole-expanding preparation stage; Figure 6It shows a schematic structural diagram of a rotating shaft column and a horse frame member in the process of adjusting the position of a horse frame member in the preparation stage of hole expansion in a multi-step continuous hole expansion device of the present invention; Figure 7 The figure shows a three-dimensional structural diagram of a multi-step continuous hole enlarging device in the process of installing a horse rod in the hole enlarging stage in the present invention; Figure 8 It shows a schematic structural diagram of a rotating shaft column and a horse frame member in the hole enlarging stage of a multi-step continuous hole enlarging device in the present invention; Fig. 9 Shown is a three-dimensional structural schematic diagram of a multi-step continuous hole expanding device in the hole expanding stage of the present invention.

[0020] a. Blank; b. Hammer head; 10. Flat hammer anvil; 11. Connecting block; 111. Limiting groove; 112. Limiting baffle; 113. Through groove; 1131. Lower through groove; 1132. Arc through groove; 1133. Upper through groove; 20. Horse frame hammer anvil; 21. Horse rod; 211. Fixing ring; 30. Rotating shaft column; 31. Cutting surface; 32. Limiting protrusion; 40. Connecting plate; 41. Limiting strip; 50. Horse frame piece; 51. Horse rod groove; 52. Anti-slip groove. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0022] like Figure 3 As shown, a multi-step continuous hole reaming device comprises a flat hammer anvil 10, a blank a, a hammer head b and a horse stick 21, two connecting blocks 11 are integrally fixedly connected to both sides of the flat hammer anvil 10, a rotating shaft column 30 is movably inserted into the two connecting blocks 11 on the same side, a connecting plate 40 with an L-shaped longitudinal section is fixedly connected to the outer periphery of the middle part of the rotating shaft column 30, the L-shaped bending part of the connecting plate 40 away from the rotating shaft column 30 faces the flat hammer anvil 10, and a horse frame 50 is fixedly connected to the end of the L-shaped bending part; When the continuous hole enlarging device of the present invention is in operation, the blank a is first placed at the center of the top of the flat hammer anvil 10, and the two horse frame members 50 are simultaneously moved to rotate around the rotating shaft column 30, so that the horse frame members 50 are separated from the top of the flat hammer anvil 10 and placed in an "eight" shape, that is, Figure 3 After the blank a is upset and punched, the horse frame 50 is manually moved to rotate around the rotating shaft column 30 until the horse frame 50 stands vertically on the top of the flat hammer anvil 10, that is, Fig. 9In the state shown, the bottom of the vertically standing horse frame 50 and the top of the flat hammer anvil 10 are in contact, and a horse rod groove 51 is provided on the top of the horse frame 50; after the punching, the blank a is sleeved around the central part of the horse rod 21 and the horse rod 21 is placed horizontally in the horse rod groove 51 on the top of the two horse frame members 50, and the hammer head b acts on the punched blank a to realize the subsequent hole expansion stage. Compared with the prior art in which the flat hammer anvil 10 is replaced with a horse frame hammer anvil 20 to realize the continuous upsetting, punching and hole expansion of the workpiece; the present invention can form a structure similar to the horse frame hammer anvil 20 by only bending the horse frame members 50 on both sides of the flat hammer anvil 10 after the upsetting and punching operations, and then the subsequent hole expansion operation can be carried out. Since the operation of bending the horse frame member 50 to form a structure similar to the horse frame hammer anvil 20 is simple, time-saving and labor-saving, the overall processing efficiency is greatly improved, thereby realizing continuous operation.

[0023] It should be noted that if Figure 3 As shown, the plane where XY is located forms the horizontal plane in the present invention; the plane where XZ is located forms the longitudinal section in the present invention; and the plane where YZ is located forms the vertical section in the present invention.

[0024] In the present invention, in the process of manually bending the horse frame 50 to rotate it around the rotating shaft column 30 until the horse frame 50 stands vertically on the top of the flat hammer anvil 10, in order to make the position accuracy and stability of the horse frame 50 standing on the top of the flat hammer anvil 10 better, the present invention makes the following arrangements: A through groove 113 is provided in the middle of the connecting block 11, and the top of the through groove 113 passes through the top of the connecting block 11 so that the longitudinal section of the connecting block 11 is "U"-shaped. The through groove 113 includes an upper through groove 1133, an arc through groove 1132 and a lower through groove 1131 arranged in sequence from top to bottom. The periphery of the shaft column 30 is processed with symmetrically arranged cutting surfaces 31, and the spacing between the two symmetrically arranged cutting surfaces 31 is smaller than the diameter of the shaft column 30; the connecting plate 40 is fixedly connected to the periphery of the middle part and is located in the middle position of the two cutting surfaces 31; the diameter of the arc through groove 1132 is larger than the diameter of the shaft column 30, and the widths of the upper through groove 1133 and the lower through groove 1131 match the spacing between the two symmetrically arranged cutting surfaces 31.

[0025] The process of manually moving the horse frame 50 to rotate it around the shaft column 30 until the horse frame 50 stands vertically on the top of the flat hammer anvil 10 includes two steps: step 1 and step 2. Before step 1, the shaft column 30 and the horse frame 50 are in the position as shown in FIG. Figure 4As shown, the shaft column 30 is located at a position coaxial with the arc groove 1132. At this time, the symmetrically arranged cutting surface 31 and the lower groove 1131 are not parallel in the vertical plane. Since the diameter of the shaft column 30 is larger than the width of the lower groove 1131, the shaft column 30 is stuck in the arc groove 1132; step one of moving the horse frame 50: moving the horse frame 50 so that it can rotate with the shaft column 30 and the connecting plate 40 as a whole with the axis of the shaft column 30 as the center of the circle. In this process, since the diameter of the arc groove 1132 is larger than the diameter of the shaft column 30, the flexibility of rotation is improved; until it rotates to Figure 5 , Figure 6 In the state shown, the shaft column 30 is located at a coaxial position with the arc groove 1132, and the cutting surface 31 and the lower groove 1131 are located on the same vertical plane, and the bottom of the horse frame 50 is parallel to the top of the flat hammer anvil 10; then step two is performed: the horse frame 50 is loosened, and under the action of gravity, the shaft column 30, the connecting plate 40, and the horse frame 50 are lowered as a whole. At this time, since the spacing between the two cutting surfaces 31 matches the width of the lower groove 1131, it plays a guiding role in the vertical descent of the shaft column 30, the connecting plate 40, and the horse frame 50 as a whole, so that the horse frame 50 can stand vertically on the top of the flat hammer anvil 10, ensuring the stability of the vertical standing of the horse frame 50; at the same time, the accuracy of the position of the horse frame 50 in the X-axis direction is ensured.

[0026] The height of the lower through slot 1131 is h1. When the rotating shaft column 30 and the arc through slot 1132 are coaxial, the rotating shaft column 30 is rotated until the bottom of the horse frame 50 and the top of the flat hammer anvil 10 are parallel. At this time, the distance between the bottom of the horse frame 50 and the top of the flat hammer anvil 10 is h2, and h1>h2. Since h1>h2, after the horse frame 50 is loosened in step 2, the bottom of the horse frame 50 first contacts the top of the flat hammer anvil 10, and the rotating shaft column 30 has not yet contacted the bottom of the lower through slot 1131, so that the connecting block 11 can be prevented from being damaged by force in the subsequent hole expansion stage.

[0027] Both ends of the cutting surface 31 are fixedly connected with limiting protrusions 32; the limiting protrusions 32 are provided to limit the rotation shaft column 30 in the through groove 113 in the Y-axis direction, thereby preventing the rotation shaft column 30 from being separated from the through groove 113; the two limiting protrusions 32 located on the same cutting surface 31 are both located outside the two connecting blocks 11, and the distance between the two limiting protrusions 32 is d, and the distance between the two connecting blocks 11 on the side away from each other is d1, and d>d1. Since d>d1, the rotation shaft column 30 retains a certain degree of flexibility in the Y-axis direction in the through groove 113, further improving the flexibility of the rotation shaft column 30 to move and rotate in the circular arc through groove 1132 when the rotation shaft column 30 and the circular arc through groove 1132 are coaxial.

[0028] like Figure 6As shown, in order to ensure that the shaft column 30 and the limiting protrusion 32 as a whole do not separate from the circular arc groove 1132 in the Y-axis direction when the shaft column 30 and the circular arc groove 1132 are coaxial, the present invention makes the following arrangements: the distance between the end of the limiting protrusion 32 away from the cutting surface 31 and the cutting surface 31 is q, and when the shaft column 30 and the circular arc groove 1132 are coaxial, the distance between the outer periphery of the shaft column 30 and the inner wall of the circular arc groove 1132 is q1, and q>2q1.

[0029] A limiting strip 41 is fixedly connected to the connecting plate 40 , and a limiting groove 111 is provided on the top of the connecting block 11 , and the limiting groove 111 matches the limiting strip 41 .

[0030] By providing the limiting groove 111 and the limiting strip 41, in step 2, by moving the positions of the rotating shaft column 30, the connecting plate 40, and the horse frame 50 as a whole so that the limiting strip 41 is inserted into the limiting groove 111, the rotating shaft column 30, the connecting plate 40, and the horse frame 50 as a whole can be further accurately limited on the Y axis, and the position accuracy of the horse frame 50 when standing on the top of the flat hammer anvil 10 can be further ensured. It should be noted that when the limiting strip 41 is inserted into the limiting groove 111, the bottom of the horse frame 50 contacts the top of the flat hammer anvil 10.

[0031] A horizontal groove is provided on the side away from each other of the two connecting blocks 11, in which a limit baffle 112 matching the horizontal groove is movably inserted, and the limit baffle 112 is located above the circular arc groove 1132; the middle part of the limit baffle 112 is processed into an arc shape, and the curvature of the arc shape matches the outer circumferential curvature of the shaft column 30. When the shaft column 30 and the circular arc groove 1132 are coaxial, the outer circumferential arc surface of the shaft column 30 fits with the arc-shaped middle part of the limit baffle 112.

[0032] After the workpiece is processed, the device needs to be restored to Figure 3 In the state shown, similarly, only the reverse operation is required. First, the shaft column 30, the connecting plate 40, and the horse frame member 50 are lifted up as a whole so that the shaft column 30 moves to the coaxial height with the arc groove 1132. At this time, the limiting baffle 112 can be set to control the overall raising degree of the shaft column 30, the connecting plate 40, and the horse frame member 50, so that when the shaft column 30 is against the limiting baffle 112, the shaft column 30 can be located at the coaxial height with the arc groove 1132; at the same time, the limiting baffle 112 is of detachable design. After the limiting baffle 112 is pulled out from the horizontal groove, it is convenient for the shaft column 30 to pass through the upper groove 1133 and be separated from the connecting block 11, thereby facilitating the maintenance and replacement of the shaft column 30, the connecting plate 40, and the horse frame member 50 as a whole.

[0033] When the two horse frames 50 stand vertically on the top of the flat hammer anvil 10, the distance between the two horse frames 50 is greater than twice the width of the hammer head b, thereby preventing the hammer head b from hitting the top of the horse frames 50 during operation.

[0034] The bottom of the longitudinal section of the horse member 50 is in a cone shape, so as to increase the force-bearing area of ​​the bottom of the horse member 50 , thereby reducing the pressure of the bottom of the horse member 50 on the top of the flat hammer anvil 10 .

[0035] The middle of the horse rod groove 51 is provided with an anti-slip groove 52 whose diameter is larger than that of the horse rod groove 51. The two ends of the horse rod 21 are fixedly sleeved with fixing rings 211, and the diameter of the fixing rings 211 matches the anti-slip groove 52. By providing the fixing rings 211 and the anti-slip groove 52, the horse rod 21 can be limited in the X-axis direction, so that the horse rod 21 is separated from the horse rod groove 51 during the hole expansion operation.

[0036] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them.

Claims

1. A multi-step continuous hole expanding device, comprising a flat hammer anvil (10), a blank (a), a hammer head (b) and a hammer bar (21), characterized in that: Two connecting blocks (11) are integrally fixedly connected to both sides of the flat hammer anvil (10); the two connecting blocks (11) on the same side are movably plugged with a rotating shaft column (30); a connecting plate (40) having an L-shaped longitudinal section is fixedly connected to the periphery of the middle part of the rotating shaft column (30); the L-shaped bending portion of the connecting plate (40) away from the rotating shaft column (30) faces the flat hammer anvil (10), and a horse frame member (50) is fixedly connected to the end of the L-shaped bending portion; During the upsetting and punching stages of the blank (a), the blank (a) is placed at the center of the top of the flat hammer anvil (10), and the two horse racks (50) are separated from the top of the flat hammer anvil (10) and placed in an "eight" shape; after the blank (a) is upset and punched, the horse rack (50) is manually moved to rotate around the rotating shaft column (30) until the horse rack (50) stands vertically on the top of the flat hammer anvil (10), and the bottom of the vertically standing horse rack (50) and the top of the flat hammer anvil (10) are in contact, and a horse rod groove (51) is opened on the top of the horse rack (50); after the punching of the blank (a), the horse rod (21) is sleeved on the outer periphery of the center of the horse rod (21) and the horse rod (21) is placed horizontally in the horse rod groove (51) on the top of the two horse racks (50), and the hammer head (b) acts on the punched blank (a) to realize the subsequent hole expansion stage.

2. A multi-step continuous hole expanding device according to claim 1, characterized in that: A through slot (113) is provided in the middle of the connecting block (11), and the top of the through slot (113) passes through the top of the connecting block (11), so that the longitudinal section of the connecting block (11) is in a "U" shape.

3. A multi-step continuous hole expanding device according to claim 2, characterized in that: The outer periphery of the rotating shaft column (30) is processed with symmetrically arranged cutting surfaces (31), and the distance between the two symmetrically arranged cutting surfaces (31) is smaller than the diameter of the rotating shaft column (30); the connecting plate (40) is fixedly connected to the outer periphery of the middle part and is located in the middle position of the two cutting surfaces (31); The through groove (113) comprises an upper through groove (1133), a circular arc through groove (1132) and a lower through groove (1131) which are arranged in sequence from top to bottom; the diameter of the circular arc through groove (1132) is greater than the diameter of the rotating shaft column (30); the widths of the upper through groove (1133) and the lower through groove (1131) match the spacing between the two symmetrically arranged cutting surfaces (31).

4. A multi-step continuous hole expanding device according to claim 3, characterized in that: The height of the lower through groove (1131) is h1. When the rotating shaft column (30) and the arc through groove (1132) are coaxial, the rotating shaft column (30) is rotated until the bottom of the horse frame (50) and the top of the flat hammer anvil (10) are parallel. At this time, the distance between the bottom of the horse frame (50) and the top of the flat hammer anvil (10) is h2, and h1>h2.

5. The multi-step continuous hole expanding device according to claim 3, characterized in that: Both ends of the cutting surface (31) are fixedly connected to limiting protrusions (32); the two limiting protrusions (32) located on the same cutting surface (31) are located outside the two connecting blocks (11); the distance between the two limiting protrusions (32) is d; the distance between the two connecting blocks (11) on the sides away from each other is d1, and d>d1.

6. A multi-step continuous hole expanding device according to claim 5, characterized in that: The distance between the end of the limiting protrusion (32) away from the cutting surface (31) and the cutting surface (31) is q, and when the rotating shaft column (30) and the circular arc groove (1132) are coaxial, the distance between the outer periphery of the rotating shaft column (30) and the inner wall of the circular arc groove (1132) is q1, and q>2q1.

7. The multi-step continuous hole expanding device according to claim 3, characterized in that: A horizontal groove is provided on one side of the two connecting blocks (11) that is away from each other. A limit baffle (112) matching the horizontal groove is movably inserted into the horizontal groove, and the limit baffle (112) is located above the circular arc groove (1132).

8. A multi-step continuous hole expanding device according to claim 7, characterized in that: The middle portion of the limit baffle (112) is processed into an arc shape, and the curvature of the arc shape matches the curvature of the outer circumference of the shaft column (30). When the shaft column (30) and the circular arc groove (1132) are coaxial, the outer circumferential arc surface of the shaft column (30) and the arc-shaped middle portion of the limit baffle (112) fit together.

9. The multi-step continuous hole expanding device according to claim 1, characterized in that: A limiting strip (41) is fixedly connected to the connection plate (40), a limiting groove (111) is provided on the top of the connection block (11), and the limiting groove (111) matches the limiting strip (41).

10. The multi-step continuous hole expanding device according to claim 1, characterized in that: The middle of the horse stick groove (51) is provided with an anti-slip groove (52) having a diameter larger than that of the horse stick groove (51); fixing rings (211) are provided at both ends of the horse stick (21), and the diameter of the fixing rings (211) matches that of the anti-slip groove (52).

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