Automatic cutter replacing device of numerical control electric spark forming machine tool

Abstract

The invention discloses an automatic tool changing device of a numerical control electric spark forming machine tool, which comprises a fixed bracket, a rotating body, a first rotating driving mechanism, a linear driving mechanism, a tool magazine and a second rotating driving mechanism, and is characterized in that the fixed bracket is mounted on a stand column of the electric spark forming machine tool; the rotating body is mounted on the fixed bracket through a first rotating driving mechanism; the linear driving mechanism is mounted on the rotating body; and the tool magazine is mounted on the linear driving mechanism through the second rotary driving mechanism. The first rotating driving mechanism drives the rotating body to rotate so as to drive the linear driving mechanism, the tool magazine and the second rotating driving mechanism to rotate to proper positions, the linear driving mechanism drives the second rotating driving mechanism and the tool magazine to linearly move, and the second rotating driving mechanism drives the tool magazine to rotate to a relatively open position. And the spindle head moves to clamp the tool, automatic replacement of the electric spark tool is achieved, cost is low, and the structure is simple.

Description

Technical Field

[0001] The invention relates to the technical field of tool replacement devices, and more particularly to an automatic tool replacement device for a numerically controlled electric spark forming machine tool. Background Art

[0002] At present, most of the existing CNC EDM machines use manual tool changing devices, and some use automatic tool changing devices. However, most of them use servo motors connected to pulleys and ball screws for transmission to achieve tool position conversion and clamping, which is costly and complex in structure.

[0003] Therefore, providing a simple-structured automatic tool replacement device for CNC EDM forming machines is an urgent problem to be solved by those skilled in the art. Summary of the invention

[0004] In view of this, the present invention provides an automatic tool changing device for a CNC electric spark forming machine tool, which has low cost and simple structure.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A device for automatically changing tools for a CNC electric spark forming machine tool comprises a fixed bracket, a rotating body, a first rotating drive mechanism, a linear drive mechanism, a tool magazine and a second rotating drive mechanism, wherein the fixed bracket is mounted on a column of the electric spark forming machine tool; the rotating body is mounted on the fixed bracket via the first rotating drive mechanism; the linear drive mechanism is mounted on the rotating body; and the tool magazine is mounted on the linear drive mechanism via the second rotating drive mechanism.

[0007] By adopting the above technical solution, the beneficial effects of the present invention are:

[0008] The first rotary drive mechanism drives the rotating body to rotate, so as to drive the linear drive mechanism, the tool magazine and the second rotary drive mechanism to rotate to a suitable position. The linear drive mechanism drives the second rotary drive mechanism and the tool magazine to move linearly. The second rotary drive mechanism drives the tool magazine to rotate to a relatively open position, and the spindle head moves to clamp the tool, thereby realizing automatic replacement of the EDM tool, which has low cost and simple structure.

[0009] Furthermore, the first rotation drive mechanism includes a first cylinder, a first rack and a first gear shaft, the first cylinder is mounted on the fixed bracket through a first cylinder support; the first rack is mounted on the telescopic rod of the first cylinder; the first gear shaft is rotatably connected to the fixed bracket, the first rack is meshedly connected to the first gear of the first gear shaft, and the rotating body is fixedly connected to the shaft of the first gear shaft.

[0010] Furthermore, the top of the first gear shaft is rotatably connected to the upper arm of the fixed bracket through a first transmission support assembly; the bottom of the first gear shaft is rotatably connected to the lower arm of the fixed bracket through a second transmission support assembly; and the rotating body is fixedly connected to the middle of the shaft of the first gear shaft.

[0011] Furthermore, the first transmission support assembly includes a first deep groove ball bearing, a first pressure cover and a first spacer, the first pressure cover, the first deep groove ball bearing and the first spacer are arranged from top to bottom between the shaft body of the first gear shaft and the upper support arm, and the first pressure cover is connected to the fixed bracket by bolts, the bottom end of the first pressure cover abuts on the outer ring of the first deep groove ball bearing; the outer ring of the first deep groove ball bearing is fixedly connected to the fixed bracket, and the inner ring of the first deep groove ball bearing is rotatably connected to the shaft body of the first gear shaft; the upper end of the first spacer abuts on the inner ring of the first deep groove ball bearing, and the lower end of the first spacer abuts on the rotating body; the second transmission support assembly includes a second deep groove ball bearing. A deep groove ball bearing, a spacer sleeve, a second pressure cover and a first locking nut, wherein the second deep groove ball bearing is located between the bottom of the shaft body of the first gear shaft and the lower support arm, and the outer ring of the second deep groove ball bearing is fixedly connected to the fixed bracket, and the inner ring of the second deep groove ball bearing is rotatably connected to the bottom of the shaft body of the first gear shaft; the spacer sleeve is sleeved on the bottom of the shaft body of the first gear shaft and its upper end abuts on the inner ring of the second deep groove ball bearing; the second pressure cover is sleeved on the outside of the spacer sleeve, and the second pressure cover is connected to the lower support arm by bolts, and the top of the second pressure cover abuts on the outer ring of the second deep groove ball bearing; the first locking nut is installed on the bottom end of the shaft body of the first gear shaft and abuts against the bottom end of the spacer sleeve.

[0012] Furthermore, the first rotation drive mechanism also includes two third deep groove ball bearings, the first rack is a cylindrical rack, and the first rack is threadedly connected to the telescopic rod of the first cylinder; the two third deep groove ball bearings are installed on the fixed bracket through the first bearing mounting seat, and the two third deep groove ball bearings are both at an angle of 45° with the horizontal plane to make soft contact with the cylindrical side surface of the first rack.

[0013] The beneficial effect of adopting the above further technical solution is that the overhanging end of the first rack is positioned and guided.

[0014] Furthermore, the linear drive mechanism includes a lower plate, a linear rail, an upper plate, a slider, a second cylinder and a connecting plate, the linear rail is fixed on the top of the lower plate; the upper plate is located above the lower plate and is fixedly connected to the rotating body; the upper plate is slidably connected to the linear rail through the slider; the second cylinder is fixed to the bottom of the upper plate through a second cylinder support, and the telescopic rod of the second cylinder is connected to the lower plate through the connecting plate.

[0015] Furthermore, the second rotation drive mechanism includes a third cylinder, a second rack, a core shaft, a lower rotating shaft, a tapered roller bearing, an elastic retaining ring, a second gear shaft and a second locking nut, the third cylinder is mounted on the lower plate through a third cylinder support; the second rack is mounted on the telescopic rod of the third cylinder; the lower rotating shaft and the core shaft are spaced apart inside and outside, and the lower rotating shaft is fixedly connected to the lower plate; the tapered roller bearing, the elastic retaining ring and the second gear shaft are arranged in sequence between the core shaft and the lower rotating shaft from top to bottom, the outer ring of the tapered roller bearing is fixedly connected to the lower rotating shaft, and the inner ring of the tapered roller bearing is rotatably connected to the core shaft; the inner side of the second gear shaft is fixedly connected to the core shaft, and the outer side of the second gear shaft is rotatably connected to the lower rotating shaft; the second rack passes through the lower rotating shaft and is meshed with the second gear of the second gear shaft; the second locking nut is screwed and tightened on the top of the core shaft; the tool magazine is mounted on the bottom end of the core shaft.

[0016] Furthermore, the second rotation drive mechanism also includes two fourth deep groove ball bearings, the second rack is a cylindrical rack, and the second rack is threadedly connected to the telescopic rod of the third cylinder; the two fourth deep groove ball bearings are installed on the lower plate through second bearing mounting seats, and the two fourth deep groove ball bearings are both at an angle of 45° with the horizontal plane to make soft contact with the cylindrical side surface of the second rack.

[0017] The beneficial effect of adopting the above further technical solution is that the overhanging end of the second rack is positioned and guided.

[0018] Furthermore, the tool magazine includes a mounting plate and a plurality of tool storage assemblies evenly distributed on both sides, each of the tool storage assemblies includes a left tool clamp, a right tool clamp and a spring, and the left tool clamp and the right tool clamp are correspondingly mounted on the mounting plate and connected by the spring.

[0019] Furthermore, a buffer is installed on the mounting plate through a buffer mounting seat, and a push plate is installed on the buffer, corresponding to the two travel limit positions of the lower plate.

[0020] It can be seen that the present invention provides an automatic tool replacement device for a CNC electric spark forming machine tool. Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1) All cylinders are used as power sources, which are cheaper and easier to adjust than traditional servo motors;

[0022] 2) The cylinder is used to fix the rack and mesh the gear to drive the rotation. The structure is simple, stable and reliable. The two limit points of the cylinder can be used to directly complete the conversion of the tool magazine's tool change point and storage point;

[0023] 3) The conventional tool has a steel ball locking mechanism, while the tool clamp of the present invention is directly fixed on the mounting plate, and a spring is connected between the tool clamps, which can be rotated in a small range to clamp the tool;

[0024] 4) The traditional collision mechanism adopts mechanical block dead limit or rubber soft contact, while the present invention directly adopts buffer to reduce the impact force and make the tool change position accurate and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0026] Figure 1 The accompanying drawing is a schematic structural diagram of an automatic tool changing device for a CNC EDM forming machine tool provided by the present invention;

[0027] Figure 2 The accompanying drawing is a structural schematic diagram of an automatic tool changing device for a CNC EDM forming machine tool provided by the present invention from another perspective;

[0028] Figure 3 The accompanying drawing is a schematic structural diagram of a first rotary drive mechanism provided by the present invention;

[0029] Figure 4 The accompanying drawing is a cross-sectional view of the first rotary drive mechanism provided by the present invention;

[0030] Figure 5 The accompanying drawing is a partial enlarged view of the first rotary drive mechanism provided by the present invention;

[0031] Figure 6 The accompanying drawing is a schematic structural diagram of a linear drive mechanism provided by the present invention;

[0032] Figure 7 The accompanying drawing is a schematic structural diagram of a second rotary drive mechanism provided by the present invention;

[0033] Figure 8 The accompanying drawing is a cross-sectional view of the second rotary drive mechanism provided by the present invention;

[0034] Fig. 9 The accompanying drawing is a partial enlarged view of the second rotary drive mechanism provided by the present invention;

[0035] Fig.10 The accompanying drawing is a schematic diagram of the structure of the tool magazine and the buffer provided by the present invention;

[0036] Fig.11 The accompanying drawing is a schematic structural diagram of the tool storage assembly provided by the present invention. DETAILED DESCRIPTION

[0037] 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.

[0038] like Figure 1-11 As shown, the embodiment of the present invention discloses an automatic tool replacement device for a CNC electric spark forming machine tool, comprising a fixed bracket 1, a rotating body 2, a first rotary drive mechanism 3, a linear drive mechanism 4, a tool magazine 5 and a second rotary drive mechanism 6. The fixed bracket 1 is mounted on the column of the electric spark forming machine tool; the rotating body 2 is mounted on the fixed bracket 1 through the first rotary drive mechanism 3; the linear drive mechanism 4 is mounted on the rotating body 2; and the tool magazine 5 is mounted on the linear drive mechanism 4 through the second rotary drive mechanism 6. The first rotary drive mechanism 3 of the present invention drives the rotating body 2 to rotate, so as to drive the linear drive mechanism 4, the tool magazine 5 and the second rotary drive mechanism 6 to rotate to a suitable position, the linear drive mechanism 4 drives the second rotary drive mechanism 6 and the tool magazine 5 to move linearly, and the second rotary drive mechanism 6 is used to drive the tool magazine 5 to rotate to a relatively open position, and the spindle head moves to clamp the tool, so as to realize the automatic replacement of the electric spark tool, which has low cost and simple structure.

[0039] Specifically, the first rotary drive mechanism 3 includes a first cylinder 31, a first rack 32 and a first gear shaft 33. The first cylinder 31 is mounted on the fixed bracket 1 through a first cylinder support 34. The first rack 32 is mounted on the telescopic rod of the first cylinder 31. The first gear shaft 33 is rotatably connected to the fixed bracket 1. The first rack 32 is meshed with the first gear of the first gear shaft 33. The rotating body 2 is fixedly connected to the shaft of the first gear shaft 33. When changing the tool, the telescopic rod of the first cylinder 31 extends, driving the first rack 32 to move, causing the first gear of the first gear shaft 33 meshed with it to rotate, and then driving the rotating body 2 and the linear drive structure 4, the second rotary drive structure 6 and the tool magazine 5 to rotate together.

[0040] In order to facilitate the routing of wires and pipelines, a wiring trough 7 may be installed on the fixed bracket 1 .

[0041] Specifically, the top of the shaft body of the first gear shaft 33 is rotatably connected to the upper arm of the fixed bracket 1 through the first transmission support assembly; the bottom of the shaft body of the first gear shaft 33 is rotatably connected to the lower arm of the fixed bracket 1 through the second transmission support assembly; the rotating body 2 is fixedly connected to the middle part of the shaft body of the first gear shaft 33.

[0042] Specifically, the first transmission support assembly includes a first deep groove ball bearing 34, a first pressure cover 35 and a first spacer 36. The first pressure cover 35, the first deep groove ball bearing 34 and the first spacer 36 are arranged from top to bottom between the shaft body of the first gear shaft 33 and the upper support arm, and the first pressure cover 35 is connected to the fixed bracket 1 by bolts, and the bottom end of the first pressure cover 35 abuts on the outer ring of the first deep groove ball bearing 34; the outer ring of the first deep groove ball bearing 34 is fixedly connected to the fixed bracket 1, and the inner ring of the first deep groove ball bearing 34 is rotatably connected to the shaft body of the first gear shaft 33; the upper end of the first spacer 36 abuts on the inner ring of the first deep groove ball bearing 34, and the lower end of the first spacer 36 abuts on the rotating body 2; the second transmission support assembly includes a second deep groove ball bearing 3 7. A spacer sleeve 38, a second pressure cover 39 and a first locking nut 310. The second deep groove ball bearing 37 is located between the bottom of the shaft body of the first gear shaft 33 and the lower support arm, and the outer ring of the second deep groove ball bearing 37 is fixedly connected to the fixed bracket 1, and the inner ring of the second deep groove ball bearing 37 is rotatably connected to the bottom of the shaft body of the first gear shaft 33; the spacer sleeve 38 is fitted on the bottom of the shaft body of the first gear shaft 33 and its upper end abuts on the inner ring of the second deep groove ball bearing 37; the second pressure cover 39 is fitted on the outside of the spacer sleeve 38, and the second pressure cover 39 is connected to the lower support arm by bolts, and the top of the second pressure cover 39 abuts on the outer ring of the second deep groove ball bearing 37; the first locking nut 310 is installed on the bottom end of the shaft body of the first gear shaft 33 and abuts against the bottom end of the spacer sleeve 38.

[0043] In order to further optimize the technical solution of the present invention, the first rotary drive mechanism 3 also includes two third deep groove ball bearings 311, the first rack 32 is a cylindrical rack, and the first rack 32 is threadedly connected to the telescopic rod of the first cylinder 31; the two third deep groove ball bearings 311 are installed on the fixed bracket 1 through the first bearing mounting seat 312, and the two third deep groove ball bearings 311 are both at an angle of 45° with the horizontal plane to softly contact the cylindrical side surface of the first rack 32, thereby realizing positioning and guiding the overhanging end of the first rack 32.

[0044] In order to improve the sealing performance, a sealing ring 313 is installed between the first pressure cover 35 and the first gear shaft 33 .

[0045] Specifically, the linear drive mechanism 4 includes a lower plate 41, a linear rail 42, an upper plate 43, a slider 44, a second cylinder 45 and a connecting plate 46. The linear rail 42 is fixed on the top of the lower plate 41; the upper plate 43 is located above the lower plate 41 and is fixedly connected to the rotating body 2; the upper plate 43 is slidably connected to the linear rail 42 through the slider 44; the second cylinder 45 is fixed to the bottom of the upper plate 43 through the second cylinder support 47, and the telescopic rod of the second cylinder 45 is connected to the lower plate 41 through the connecting plate. When changing the tool, the telescopic rod of the second cylinder 45 is telescopically extended to drive the lower plate 41 to translate on the linear rail 42, driving the second rotary drive mechanism 6 and the tool magazine 5 to perform linear motion together.

[0046] Specifically, the second rotary drive mechanism 6 includes a third cylinder 61, a second rack 62, a core shaft 63, a lower rotating shaft 64, a tapered roller bearing 65, an elastic retaining ring 66, a second gear shaft 67 and a second locking nut 68. The third cylinder 61 is mounted on the lower plate 41 through a third cylinder support 69; the second rack 62 is mounted on the telescopic rod of the third cylinder 61; the lower rotating shaft 64 and the core shaft 63 are spaced apart inside and outside, and the lower rotating shaft 64 is fixedly connected to the lower plate 61; the tapered roller bearing 65, the elastic retaining ring 66 and the second gear shaft 67 are fixedly connected to the lower plate 61. The shaft 67 is arranged between the mandrel 63 and the lower rotating shaft 64 from top to bottom, the outer ring of the tapered roller bearing 65 is fixedly connected to the lower rotating shaft 64, and the inner ring of the tapered roller bearing 65 is rotatably connected to the mandrel 63; the inner side of the second gear shaft 67 is fixedly connected to the mandrel 63, and the outer side of the second gear shaft 67 is rotatably connected to the lower rotating shaft 64; the second rack 62 penetrates the lower rotating shaft 64 and is meshed with the second gear of the second gear shaft 67; the second locking nut 68 is screwed and fastened to the top of the mandrel 63; the tool magazine 5 is installed at the bottom of the mandrel 63. When changing the tool, the telescopic rod of the third cylinder 61 is extended and retracted to drive the second rack 62 to move, so that the second gear of the second gear shaft 67 meshed with it rotates, and then drives the mandrel 63 and the tool magazine 5 to rotate together.

[0047] In order to further optimize the technical solution of the present invention, the second rotary drive mechanism 6 also includes two fourth deep groove ball bearings 610, the second rack 62 is a cylindrical rack, and the second rack 62 is threadedly connected to the telescopic rod of the third cylinder 61; the two fourth deep groove ball bearings 610 are installed on the lower plate 41 through the second bearing mounting seat 611, and the two fourth deep groove ball bearings 610 are both at an angle of 45° to the horizontal plane to softly contact the cylindrical side surface of the second rack 62, thereby realizing positioning and guiding the overhanging end of the second rack 62.

[0048] Specifically, the tool magazine 5 includes a mounting plate 51 and a plurality of tool storage assemblies 52 evenly distributed on both sides. Each tool storage assembly 52 includes a left tool clamp 521, a right tool clamp 522 and a spring 523. The left tool clamp 521 and the right tool clamp 522 are correspondingly mounted on the mounting plate 51 and are connected by a spring 523. When the tool contacts the left tool clamp 521 and the right tool clamp 522, the left tool clamp 521 and the right tool clamp 522 are blocked, the spring 523 opens and clamps the tool, and the spindle head moves to the top of the corresponding tool to grab and realize tool change.

[0049] In order to further optimize the technical solution of the present invention, a buffer 9 is installed on the mounting plate 51 through the buffer mounting seat 8, and a push plate 10 is installed on the buffer 9 and corresponds to the two travel limit positions of the lower plate 41.

[0050] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0051] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An automatic tool changing device for a CNC electric spark forming machine tool, characterized in that: It includes a fixed bracket, a rotating body, a first rotating drive mechanism, a linear drive mechanism, a tool magazine and a second rotating drive mechanism. The fixed bracket is installed on the column of the electric spark forming machine tool; the rotating body is installed on the fixed bracket through the first rotating drive mechanism; the linear drive mechanism is installed on the rotating body; and the tool magazine is installed on the linear drive mechanism through the second rotating drive mechanism.

2. The automatic tool changing device for CNC EDM machine tool according to claim 1, characterized in that: The first rotation drive mechanism includes a first cylinder, a first rack and a first gear shaft. The first cylinder is installed on the fixed bracket through a first cylinder support; the first rack is installed on the telescopic rod of the first cylinder; the first gear shaft is rotatably connected to the fixed bracket, the first rack is meshed with the first gear of the first gear shaft, and the rotating body is fixedly connected to the shaft body of the first gear shaft.

3. The automatic tool changing device for CNC EDM machine tool according to claim 2, characterized in that: The top of the shaft body of the first gear shaft is rotatably connected to the upper arm of the fixed bracket through the first transmission support assembly; the bottom of the shaft body of the first gear shaft is rotatably connected to the lower arm of the fixed bracket through the second transmission support assembly; the rotating body is fixedly connected to the middle part of the shaft body of the first gear shaft.

4. The automatic tool changing device for CNC EDM machine tool according to claim 3 is characterized in that: The first transmission support assembly includes a first deep groove ball bearing, a first pressure cover and a first spacer, wherein the first pressure cover, the first deep groove ball bearing and the first spacer are arranged from top to bottom between the shaft body of the first gear shaft and the upper support arm, and the first pressure cover is connected to the fixed bracket by bolts, and the bottom end of the first pressure cover abuts against the outer ring of the first deep groove ball bearing; the outer ring of the first deep groove ball bearing is fixedly connected to the fixed bracket, and the inner ring of the first deep groove ball bearing is rotatably connected to the shaft body of the first gear shaft; the upper end of the first spacer abuts against the inner ring of the first deep groove ball bearing, and the lower end of the first spacer abuts against the rotating body; the second transmission support assembly includes a second deep groove ball shaft A bearing, a spacer sleeve, a second pressure cover and a first locking nut, the second deep groove ball bearing is located between the bottom of the shaft body of the first gear shaft and the lower support arm, and the outer ring of the second deep groove ball bearing is fixedly connected to the fixed bracket, and the inner ring of the second deep groove ball bearing is rotatably connected to the bottom of the shaft body of the first gear shaft; the spacer sleeve is fitted on the bottom of the shaft body of the first gear shaft and its upper end abuts on the inner ring of the second deep groove ball bearing; the second pressure cover is fitted on the outside of the spacer sleeve, and the second pressure cover is connected to the lower support arm by bolts, and the top of the second pressure cover abuts on the outer ring of the second deep groove ball bearing; the first locking nut is installed at the bottom end of the shaft body of the first gear shaft and abuts against the bottom end of the spacer sleeve.

5. The automatic tool changing device for CNC EDM machine tool according to any one of claims 2 to 4, characterized in that: The first rotary drive mechanism also includes two third deep groove ball bearings, the first rack is a cylindrical rack, and the first rack is threadedly connected to the telescopic rod of the first cylinder; the two third deep groove ball bearings are installed on the fixed bracket through the first bearing mounting seat, and the two third deep groove ball bearings are both at an angle of 45° with the horizontal plane to make soft contact with the cylindrical side surface of the first rack.

6. The automatic tool changing device for CNC EDM machine tool according to claim 1 or 2, characterized in that: The linear drive mechanism includes a lower plate, a linear rail, an upper plate, a slider, a second cylinder and a connecting plate, wherein the linear rail is fixed to the top of the lower plate; the upper plate is located above the lower plate and is fixedly connected to the rotating body; the upper plate is slidably connected to the linear rail through the slider; the second cylinder is fixed to the bottom of the upper plate through a second cylinder support, and the telescopic rod of the second cylinder is connected to the lower plate through the connecting plate.

7. The automatic tool changing device for CNC EDM machine tool according to claim 6, characterized in that: The second rotary drive mechanism comprises a third cylinder, a second rack, a core shaft, a lower rotating shaft, a tapered roller bearing, an elastic retaining ring, a second gear shaft and a second locking nut, wherein the third cylinder is mounted on the lower plate through a third cylinder support; the second rack is mounted on the telescopic rod of the third cylinder; the lower rotating shaft and the core shaft are spaced apart inside and outside, and the lower rotating shaft is fixedly connected to the lower plate; the tapered roller bearing, the elastic retaining ring and the second gear shaft are arranged in sequence between the core shaft and the lower rotating shaft from top to bottom, the outer ring of the tapered roller bearing is fixedly connected to the lower rotating shaft, and the inner ring of the tapered roller bearing is rotatably connected to the core shaft; the inner side of the second gear shaft is fixedly connected to the core shaft, and the outer side of the second gear shaft is rotatably connected to the lower rotating shaft; the second rack passes through the lower rotating shaft and is meshed with the second gear of the second gear shaft; the second locking nut is screwed and fastened to the top end of the core shaft; the tool magazine is mounted at the bottom end of the core shaft.

8. The automatic tool changing device for CNC EDM machine tool according to claim 7, characterized in that: The second rotary drive mechanism also includes two fourth deep groove ball bearings, the second rack is a cylindrical rack, and the second rack is threadedly connected to the telescopic rod of the third cylinder; the two fourth deep groove ball bearings are installed on the lower plate through second bearing mounting seats, and the two fourth deep groove ball bearings are both at an angle of 45° with the horizontal plane to make soft contact with the cylindrical side surface of the second rack.

9. The automatic tool changing device for CNC EDM machine tool according to claim 7, characterized in that: The tool magazine includes a mounting plate and a plurality of tool storage assemblies evenly distributed on both sides, each of the tool storage assemblies includes a left tool clamp, a right tool clamp and a spring, and the left tool clamp and the right tool clamp are correspondingly mounted on the mounting plate and connected by the spring.

10. The automatic tool changing device for CNC EDM machine tool according to claim 9, characterized in that: A buffer is installed on the installation plate through a buffer mounting seat, and a push plate is installed on the buffer and corresponds to two travel limit positions of the lower plate.

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