Automatic tool changing method for ultra-high speed air bearing spindle CNC machine tool and machine tool thereof

Abstract

An automatic tool changing method for an ultra-high-speed air-floating spindle CNC numerical control machine tool and the machine tool thereof, wherein the method comprises the following steps: S1, sending a tool changing command; S2, a sensor detecting whether there is a tool on the spindle, S3, performing a tool return action; S4, performing a tool grabbing action; S5, moving the spindle above the tool holder, the spindle aligning the tool pre-installed in the tool holder; S6, a Z-direction driving mechanism driving the spindle downward, so that the reference surface of the spindle contacts the positioning surface of the positioning clamp of the tool; S7, the spindle cylinder is depressurized, the spindle disc spring stretches to drive the driving rod to rise, the locking nozzle follows the driving rod to rise, the locking nozzle retracts to clamp the upper part of the tool, and the reference surface of the spindle and the positioning surface of the positioning clamp are kept in a close contact state; S8, the Z-direction driving device drives the spindle to rise synchronously with the grasped tool, and the machine enters a processing state. The present invention has the advantage of no need to align the tool after tool changing.

Description

Technical Field

[0001] The invention relates to an automatic tool changing method of an ultra-high-speed air-floating spindle CNC numerically controlled machine tool and the machine tool. Background Art

[0002] CNC machine tools can be divided into three categories according to their spindle speed: low-speed, high-speed and ultra-high-speed spindles. Among them, ultra-high-speed machine tools are mainly used for high-mirror processing of workpieces, so they are also called high-gloss machines in the industry.

[0003] At present, most high-gloss machines use manual tool changing, which has the problems of slow tool changing speed and poor precision. Some people now imitate the tool changing method of low-speed machines and change tools automatically on high-gloss machines, that is, use a tool holder with a bevel positioning to clamp the tool, and the spindle of the high-gloss machine grasps the tool holder with bevel positioning to achieve tool changing. However, this tool changing method is difficult to apply to high-gloss machines with a rotation speed of more than 80,000 rpm due to the large size and heavy mass of the tool holder and poor dynamic balance of accumulated tolerance. Another tool changing method is to install multiple high-gloss spindles (usually three) on one machine, and install different tools on several spindles respectively, and sequentially process the same workpiece to replace the tool changing function. This tool changing method is limited by the number of spindles, and can only change tools with the same number of spindles.

[0004] In order to solve the above problems, Chinese patent document CN104128831A discloses an ultra-high-speed electric spindle automatic tool changing device and method thereof, wherein the automatic tool changing method includes the following steps: the electric spindle moves to the front end of the caliper, and the tool is pushed into the caliper for clamping; the electric spindle is separated from the tool and moves to the tool change checker for tool change logic check; after checking that the tool change is successful, the electric spindle moves to the upper end of the next caliper, and the tool is loaded into the spring clamp tool chuck, and the spring clamp tool chuck on the electric spindle clamps the tool; the electric spindle and the clamped tool are moved out of the caliper laterally, and the tool length is measured to complete the tool change. However, this tool changing device and tool changing method have a new problem, that is, tool alignment needs to be performed after each tool change, and tool alignment takes time, which affects the processing efficiency of the product, especially for products with complex structures and frequent tool changes, which will greatly reduce the processing efficiency of the product; in addition, frequent tool alignment will also have an adverse effect on the tool tip.

[0005] In order to solve the problem of frequent tool alignment, Chinese patent document CN113103045A discloses a tool magazine, including a placement rack and at least two tools, the placement rack is provided with at least two placement positions, and a positioning part is provided at the bottom of the placement position; the tool is placed in the placement position, and the tip of the tool is in contact with the positioning part. When using the processing equipment of this tool magazine, the tool alignment operation can be avoided when replacing the tool, which saves tool alignment time, simplifies the processing process, and effectively improves production efficiency. However, this kind of processing equipment that uses a special tool magazine to avoid tool alignment has a certain pressure on the tool handle when grabbing the tool, so that the tip of the tool presses the positioning part. Over time, damage will occur between the tip of the tool and the positioning part, affecting the Z-direction accuracy of the tool.

[0006] How to realize the ultra-high-speed spindle automatic tool changing technology that can automatically change tools without tool alignment and has high Z-axis accuracy is a technical problem that needs to be solved urgently by technicians in the same industry. Summary of the invention

[0007] The object of the present invention is to provide an automatic tool changing method of an ultra-high-speed air-floating spindle CNC numerical control machine tool and a machine tool thereof, which can realize automatic tool changing without tool setting and with high tool changing accuracy.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] Provided is an automatic tool changing method for an ultra-high-speed air-bearing spindle CNC machine tool, comprising the following steps:

[0010] S1, send tool change command;

[0011] S2, the sensor detects whether there is a tool on the spindle, if yes, go to step S3, if not, go to step S4;

[0012] S3, perform the knife-returning action;

[0013] S4, perform the knife grabbing action and grab the knife according to the following steps;

[0014] S5, moving the spindle to above the tool holder, the spindle is aligned with the tool pre-installed in the tool holder, the tool comprises a tool and a positioning clamp, the positioning clamp is coaxially positioned on the tool, and the distance from the positioning surface of the positioning clamp of each tool to the tool tip is equal;

[0015] S6, the Z-axis driving mechanism drives the spindle downward, so that the reference surface of the spindle contacts the positioning surface of the positioning clamp of the tool. At the same time, the spindle cylinder built into the spindle drives the rod downward, so that the lock mouth at the lower end of the drive rod opens, and the upper part of the tool extends into the lock mouth. The spindle disc spring located at the upper part of the drive rod is compressed, and the tool holder elastic body in the tool holder is compressed under the action of the downward force of the tool. Under the action of the reaction force of the tool holder elastic body, the reference surface of the spindle contacts closely with the positioning surface of the positioning clamp.

[0016] S7, the spindle cylinder is depressurized, the spindle disc spring is stretched to drive the driving rod to rise, the locking jaw follows the driving rod to rise, the locking jaw is retracted to clamp the upper part of the tool, and the reference surface of the spindle and the positioning surface of the positioning clamp are kept in close contact;

[0017] S8, the Z-axis drive device drives the spindle and the grasped tool to rise synchronously, and the machine enters the processing state.

[0018] As an improvement to the present invention, the present invention further includes step S9 and repeating steps S2-S8, thereby realizing a cyclic tool changing function during the machining process.

[0019] As an improvement to the present invention, the step S3 includes the following steps:

[0020] S31, move the spindle to the top of the tool holder seat, aligning the spindle with the empty space of the tool holder seat;

[0021] S32, the Z-axis driving mechanism drives the spindle to move downward, the tool on the spindle moves downward to the set position, the tool holder holds the positioning clamp on the tool, and the spindle stops moving downward; the spindle cylinder in the spindle is inflated, the butterfly spring is pressed downward, the driving rod moves downward, the locking mouth opens, and the locking mouth releases the tool;

[0022] S33, the spindle moves upward, and the spindle and the tool are separated to complete the tool return.

[0023] As an improvement to the present invention, the step S5 further includes a tool assembly step:

[0024] S51, placing the knife and the positioning clamp in the special fixture, inserting the knife handle into the center hole of the positioning clamp, making the positioning surface of the positioning clamp close to the upper positioning surface of the special fixture, making the tip of the knife against the lower positioning surface of the special fixture, ensuring that the distance between the positioning surface of the positioning clamp and the tip of the knife of all knives is the same fixed value;

[0025] S52, fixing the positioning clamp on the tool handle to form a tool.

[0026] The present invention also provides a single-drive multi-spindle CNC machine tool capable of automatic tool change, which can use the above-mentioned automatic tool change method to change tools.

[0027] The present invention also provides a single-drive multi-spindle CNC machine tool with automatic tool change, comprising a frame, a processing table is provided on the frame, a tool magazine that can be extended and retracted along the Y direction is provided above the processing table, a processing part is provided above the tool magazine, the processing part comprises a spindle fixing seat, a spindle is vertically provided on the spindle fixing seat, the spindle is driven by a Z-direction driving mechanism, a tool grabbing structure for grabbing the tool is provided in the spindle, a plurality of tools are stored in the tool magazine, each of the tools has a tool and a positioning clamp, the positioning clamp is coaxially positioned on the tool, and the distance from the positioning surface of the positioning clamp of each tool to the tool tip is equal; after the tool grabbing structure grabs the tool, the positioning surface of the positioning clamp is tightly attached to the reference surface of the spindle.

[0028] As an improvement to the present invention, the knife grabbing structure includes a spindle cylinder arranged in the spindle, a driving rod connected to the output shaft of the spindle cylinder, a butterfly spring driven by the output shaft is provided at the upper end of the driving rod, and a locking mouth is provided at the lower end of the driving rod.

[0029] As an improvement to the present invention, the tool magazine is provided with a plurality of tool holder seats, each of which has a clamping portion of a positioning clamp for holding the tool, and a tool holder seat elastic body located below the clamping portion for pushing the tool upward.

[0030] As an improvement to the present invention, the clamping portion is an elastic clamping portion.

[0031] As an improvement to the present invention, the positioning clip is coaxially fixed on the handle of the knife by means of a fastener or heat shrinkage.

[0032] The core of the present invention is to design all tools to include two parts, namely, a positioning clamp and a tool, and to position the positioning clamp on the tool, and to make the positioning surfaces of the positioning clamps of all tools be at equal distances from the tool tip, and to place the tool on the tool holder of the tool magazine so that the tool holder elastic body in the tool holder pushes up the tool; when the spindle grabs the tool, the reference surface of the spindle is tightly attached to the positioning surface of the positioning clamp, thereby ensuring that no matter which tool is grabbed, the tool tip has the same height in the Z direction, and the tool tip is suspended when the tool is changed, thus achieving the purpose of not needing to align the tool and ensuring accurate Z-direction height accuracy of the tool after tool change. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the block structure of an embodiment of the method of the present invention.

[0034] Figure 2 yes Figure 1 Schematic diagram of the refined structure of the S3 step in .

[0035] Figure 3 yes Figure 1Schematic diagram of the refined structure of step S5 in .

[0036] Figure 4 It is a structural schematic diagram of the knife return of the present invention.

[0037] Figure 5 It is a structural schematic diagram of the tool changing process of the present invention.

[0038] Figure 6 It is a schematic diagram of the tool changing completion structure of the present invention.

[0039] Figure 7 It is a structural schematic diagram of the main shaft moving upward after the tool change is completed in the present invention.

[0040] Figure 8 It is a schematic diagram of the planar structure of the machine tool of the present invention.

[0041] Fig. 9 It is a structural schematic diagram of a cutting tool in the present invention.

[0042] Fig.10 It is a structural diagram of another embodiment of the tool holder of the present invention.

[0043] Fig.11 yes Fig.10 Schematic diagram of the top view structure.

[0044] Fig.12 yes Fig.10 Schematic diagram of the structure used for returning the knife.

[0045] Fig.13 yes Fig.10 Schematic diagram of the structure used for grabbing the knife.

[0046] Fig.14 It is a schematic diagram of the planar structure of an embodiment of the positioning clamp in the present invention.

[0047] Fig.15 yes Fig.14 Schematic diagram of the top plan structure.

[0048] Fig.16 yes Fig.14 Schematic diagram of the three-dimensional structure.

[0049] Fig.17 It is a schematic diagram of the top structure of the positioning protective cover of the present invention.

[0050] Fig.18 yes Fig.17 Schematic diagram of the three-dimensional structure.

[0051] Fig.19 It is a schematic diagram of the planar structure after the positioning protective sleeve is put on the positioning clip.

[0052] Fig. 20yes Fig.19 Schematic diagram of the top plan structure.

[0053] Fig.21 yes Fig. 20 AA cross-sectional structure schematic diagram.

[0054] In the figure:

[0055] Rack 1;

[0056] Processing table 2;

[0057] Tool magazine 3;

[0058] Tool holder seat 31;

[0059] A clamping portion 311;

[0060] Tool holder elastic body 312;

[0061] Processing department 4;

[0062] Spindle fixing seat 41;

[0063] Spindle 411;

[0064] Reference surface 4111;

[0065] Spindle fixing clamp 4112;

[0066] Tighten the screws 4113;

[0067] Z direction driving mechanism 412 drives;

[0068] Tool 413;

[0069] Knife 4131;

[0070] Tip 41311

[0071] Handle 41312;

[0072] Positioning clip 4132;

[0073] Positioning surface 41321;

[0074] Clamped portion 41322;

[0075] Screw 41323;

[0076] Positioning clamp upper cylinder 41324;

[0077] Upper cylinder surface 413241;

[0078] Undercut fitting hole 413242

[0079] Positioning clamp lower cylinder 41325;

[0080] Lower cylinder surface 413251;

[0081] Upper tube opening slot 41326;

[0082] Lower barrel opening slot 41327;

[0083] Positioning clip center hole 41328;

[0084] Claw grab structure 414;

[0085] Spindle cylinder 4141;

[0086] Output shaft 4142;

[0087] Driving rod 4143;

[0088] Belleville spring 4144;

[0089] Lock mouth 4145. DETAILED DESCRIPTION

[0090] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0091] See also Figure 1-Figure 3 , Figure 1-Figure 3 Disclosed is an automatic tool changing method for an ultra-high-speed air-floating spindle CNC machine tool, comprising the following steps:

[0092] S1, the CNC device of the machine tool sends a tool change command;

[0093] S2, the sensor on the machine tool detects whether there is a tool on the spindle, if there is, go to step S3, if not, go to step S4; in this embodiment, the sensor is an infrared sensor, the infrared sensor includes an infrared transmitting tube and an infrared receiving tube, the infrared transmitting tube and the infrared receiving tube are arranged oppositely, when the infrared ray emitted by the infrared transmitting tube can be received by the infrared receiving tube, it means that there is no tool at the lower end of the spindle, otherwise, it means that there is a tool at the lower end of the spindle; of course, the sensor can also use a magnetic induction switch, etc.

[0094] S3, perform the knife return action; see Figure 2 and Figure 4 ,

[0095] S31, through the cooperation of the spindle X-direction moving mechanism (not shown) and the tool magazine Y-direction moving mechanism (not shown) (i.e., the spindle fixing seat moves up and down under the drive of the Z-direction driving mechanism, and the spindle fixing seat is fixed on the X-axis fixing seat to move horizontally), the spindle is moved to the top of the tool holder seat, so that the spindle is aligned with the empty position of the tool holder seat;

[0096] S32, the Z-axis driving mechanism drives the spindle to move downward, and the tool on the spindle moves downward to a set position, so that the tool holder seat holds the positioning clamp on the tool (specifically, the lower part of the positioning clamp is provided with a clamped part, see Fig.10 ; A clamping part is provided on the upper part of the tool holder seat, and the clamping part has a certain elasticity. When the clamped part extends to the clamping clamp, the clamping clamp uses its elasticity to hold the clamped part; of course, it can also be designed to directly clamp the tool handle, or clamp the outer edge of the positioning sleeve, or use magnetic attraction, etc. according to needs), the spindle stops moving down; the spindle cylinder in the spindle is inflated, the butterfly spring is pressed down, the driving rod moves down, the locking mouth opens, and the locking mouth releases the tool;

[0097] S33, the spindle moves upward, and the spindle is separated from the tool, completing the tool return.

[0098] S4, perform the knife grabbing action and grab the knife according to the following steps, see Figure 5-Figure 7 ;

[0099] S5, by means of the cooperation between the spindle X-direction moving mechanism (not shown) and the tool magazine Y-direction moving mechanism (not shown), the spindle is moved above the tool holder seat, the spindle is aligned with the tool pre-installed in the tool holder seat, the tool comprises a tool and a positioning clamp, the positioning clamp is coaxially positioned on the tool, and the distance from the positioning surface of the positioning clamp of each tool on the tool holder seat to the tool tip is equal;

[0100] S6, the Z-axis driving mechanism drives the spindle downward, so that the reference surface of the spindle contacts the positioning surface of the positioning clamp of the tool, and at the same time, the spindle cylinder built into the spindle is inflated to make the driving rod move downward, so that the locking mouth at the lower end of the driving rod opens, and the upper part of the tool extends into the locking mouth, the spindle disc spring located at the upper part of the driving rod is compressed, and the tool holder elastic body in the tool holder is compressed under the action of the downward force of the tool, and the reference surface of the spindle is closely contacted with the positioning surface of the positioning clamp under the action of the reaction force of the tool holder elastic body;

[0101] S7, the spindle cylinder is depressurized, the spindle disc spring is stretched to drive the driving rod to rise, the locking jaw follows the driving rod to rise, the locking jaw is retracted to clamp the upper part of the tool, and the reference surface of the spindle and the positioning surface of the positioning clamp are kept in close contact;

[0102] S8, the Z-axis drive device drives the spindle and the grasped tool to rise synchronously, and the machine enters the processing state.

[0103] The core of the present invention is that when the spindle grabs the tool, the reference surface of the spindle is tightly attached to the positioning surface of the positioning clamp. Since the positioning surface and the tool tip of each tool are the same fixed value, and the tool tip is suspended when the tool is changed, it is ensured that no matter which tool is grabbed, the height of the tool tip in the Z direction is the same, so that the purpose of not having to align the tool and having accurate Z-direction accuracy of the tool after the tool change can be achieved.

[0104] Preferably, the present invention further includes step S9 and repeating steps S2-S8, thereby realizing a cyclic tool changing function during the machining process.

[0105] Preferably, the step S5 further comprises a tool assembly step: Figure 3 ;

[0106] S51, placing the knife and the positioning clamp in the special fixture, inserting the knife handle into the center hole of the positioning clamp, making the positioning surface of the positioning clamp close to the upper positioning surface of the special fixture, making the tip of the knife against the lower positioning surface of the special fixture, ensuring that the distance between the positioning surface of the positioning clamp and the tip of the knife of all knives is the same fixed value;

[0107] S52, fixing the positioning clamp on the tool handle to form a tool.

[0108] In the present invention, the tool can be pre-assembled outside the machine:

[0109] Use a special fixture outside the machine to assemble the positioning clamp and the knife, ensuring that the distance between the positioning surface of the positioning clamp of all knives and the tip of the knife is the same predetermined fixed value, and the distance is preferably accurate within 0.005mm;

[0110] like Fig.10 A first reference surface F and a second reference surface G are set in a special fixture, the positioning surface of the positioning clamp is close to the first reference surface F, and the tip of the knife is close to the second reference surface G. Then, the positioning clamp is fixed on the knife to form a tool.

[0111] The fixing methods of the positioning clip and the knife include but are not limited to mechanical methods, such as locking with screws 41323, or fixing by heat shrinking, etc.

[0112] If heat shrinking is used to achieve a close fit between the tool and the locating clamp, the locating clamp must first be heated with a high-frequency heater to expand the inner diameter of the locating clamp and the tool handle so that the tool handle can be smoothly inserted into the locating clamp, and the tool tip is in close contact with the special fixture and the second reference surface G, and the locating surface of the locating clamp is in close contact with the first reference surface F. The locating clamp is cooled, and the inner diameter of the locating clamp shrinks so that the locating clamp tightly holds the tool handle.

[0113] The present invention also provides a CNC numerically controlled machine tool with an ultra-high-speed air-floating spindle capable of automatically changing tools, and the tool can be changed using the automatic tool changing method described above.

[0114] See also Figure 8 and Fig. 9 , Figure 8 and Fig. 9The invention discloses a CNC machine tool with an ultra-high-speed air-floating spindle and automatic tool change, comprising a frame 1, a processing table 2 is provided on the frame 1, a tool magazine 3 that can be extended and retracted along the Y direction is provided above the processing table 2, a processing unit 4 is provided above the tool magazine 3, the processing unit 4 comprises a spindle fixing seat 41, a spindle 411 is vertically provided on the spindle fixing seat 41, the spindle 411 is driven by a Z-direction driving mechanism 412 (in this embodiment, the Z-direction driving mechanism 412 comprises a servo motor and a corresponding screw nut structure, the Z-direction driving mechanism The structure 412 drives the spindle fixing seat 41 to move up and down, and the spindle fixing seat 41 thereby drives the spindle 411 to move up and down. At the same time, the spindle fixing seat 41 is fixed on the X-axis fixing seat (not shown) and can move horizontally). A tool grabbing structure 414 for grabbing a tool 413 is respectively provided in the spindle 411. A plurality of tools 413 are stored in the tool magazine 3. Each tool 413 has a tool 4131 and a positioning clamp 4132 (a clamped portion 41322 having a diameter smaller than that of the positioning clamp 4132 is provided at the lower part of the positioning clamp 4132, see Fig. 9 ), the positioning clamp 4132 is coaxially fixed on the handle of the knife 4131, and the distance from the positioning surface 41321 of the positioning clamp 4132 of each knife 413 to the knife tip 41311 is equal; after the knife grabbing structure grabs the knife 413, the positioning surface 41321 of the positioning clamp 4132 is tightly attached to the reference surface 4111 of the spindle 411.

[0115] The tool can be pre-assembled outside the machine: a special fixture is used outside the machine to assemble the positioning clamp and the tool to ensure that the distance between the positioning surface of the positioning clamp of all tools and the tip of the tool is the same predetermined fixed value, and the distance is preferably accurate within 0.005mm.

[0116] Preferably, the grabber structure 414 (see Figure 4-7 ) includes a main shaft cylinder 4141 arranged in the main shaft 411, a driving rod 4143 connected to the output shaft 4142 of the main shaft cylinder 4141, a butterfly spring 4144 driven by the output shaft 4142 is provided at the upper end of the driving rod 4143, and a locking mouth 4145 is provided at the lower end of the driving rod 4143.

[0117] Preferably, the tool magazine 3 is provided with a plurality of tool holders 31, each tool holder 31 having a clamping portion 311 of a positioning clamp 4132 for holding a tool 413, and a tool holder elastic body 312 located below the clamping portion 311 for pushing the tool 413 upward. In the present invention, the clamping portion 311 may be an elastic clamping portion, a pneumatic clamping portion, an electric clamping portion, or a magnetic clamping portion, etc.; the tool holder elastic body 312 may be a tool holder spring, a tool holder elastic rubber, or a tool holder elastic air cushion, etc.

[0118] See also Fig.10 In the present invention, the tool holder seat 31 comprises a clamping portion 311 of a positioning clamp 4132 for holding a tool 413, and a tool holder seat elastic body 312 for pushing the tool 413 upward. In this embodiment, the clamping portion 311 comprises a horizontal clamping surface (3111) and a sliding member (3112) connected perpendicularly to the horizontal clamping surface (3111), and the horizontal clamping surface (3111) and the sliding member (3112) form an L-shape. An elastic bayonet 3113 is provided on the side of the horizontal clamping surface (3111) away from the sliding member (3112) (see Fig.11 ), the elastic bayonet 3113 is used to carry the tool 413.

[0119] When you want to return the knife, Fig.12 As shown, the spindle moves the tool 413 to the vicinity of the clamping portion 311, so that the clamped portion 41322 of the tool 413 is aligned with the elastic bayonet 3113, and the tool 413 clamps the clamped portion 41322 in the elastic bayonet 3113 from the side along the direction of the first arrow 415 to complete the tool return.

[0120] When you want to grab the knife, Fig.13 As shown, the locking mouth 4145 of the spindle holds the tool handle on the upper part of the positioning clamp, the spindle moves slightly downward, the positioning surface 41321 of the positioning clamp 4132 is tightly attached to the reference surface 4111 of the spindle 411, the locking mouth 4145 locks the tool handle on the upper part of the positioning clamp, and the spindle is translated to remove the tool 413 from the side along the direction of the second arrow 416 to complete the tool grabbing.

[0121] See also Figure 14-16 , Figure 14-16Another positioning clamp in the present invention is disclosed. As can be seen from the figure, the positioning clamp 4132 comprises a positioning clamp upper tube 41324 and a positioning clamp lower tube 41325, wherein the positioning clamp upper tube 41324 and the positioning clamp lower tube 41325 are coaxially arranged up and down, wherein the outer diameter of the positioning clamp lower tube 41325 is larger than the outer diameter of the positioning clamp upper tube 41324, and a positioning surface 41321 is formed at the intersection of the positioning clamp upper tube 41324 and the positioning clamp lower tube 41325; a positioning clamp middle hole 41328 penetrating the positioning clamp upper tube 41324 and the positioning clamp lower tube 41325 is provided at the center of the positioning clamp upper tube 41324 and the positioning clamp lower tube 41325, and the positioning clamp upper tube 41324 and the positioning clamp lower tube 41325 are provided. At least three upper tube opening grooves 41326 and at least three lower tube opening grooves 41327 are alternately arranged on the tube wall; the upper tube opening grooves 41326 extend from the upper tube surface 413241 of the positioning clamp upper tube 41324 to the vicinity of the lower tube surface 413251 of the positioning clamp lower tube 41325, dividing the positioning clamp upper tube 41324 and the positioning clamp lower tube 41325 into at least three upper elastic sheets; the lower tube opening grooves 41327 extend from the lower tube surface 413251 of the positioning clamp lower tube 41325 to the vicinity of the upper tube surface 413241 of the positioning clamp upper tube 41324, dividing the positioning clamp lower tube 41325 and the positioning clamp upper tube 41324 into at least three lower elastic sheets.

[0122] An undercut fitting hole 413242 is provided on the positioning clamp upper cylinder 41324 near the positioning surface 41321 for fitting with the positioning protection sleeve 4133 on the main shaft.

[0123] See also Figure 17-Figure 21 The present invention also includes a positioning protective sleeve 4133, which includes a bottom plate 41331, the circumference of which extends to one side to form a cylinder 41332, a center hole 41333 is provided in the center of the bottom plate 41331, the diameter of which is equal to the outer diameter of the positioning clamp upper cylinder 41324, and at least two lugs protruding into the center hole 41333 are evenly provided on the inner wall of the center hole 41333 41334 (in the present embodiment, there are three lugs 41334; of course, a structure with more than three lugs 41334 may also be designed), and arc grooves 41335 are respectively provided at one end thereof in communication with the center hole 41333 to form elastic arms 41336 relative to the lugs 41334; the positioning protective sleeve 4133 is sleeved on the positioning clamp upper tube 41324, and the lugs 41334 are clamped in the buckle fitting holes 413242 to fix the two in connection.

[0124] When the lug 41334 is stuck in the buckle fitting hole 413242 , the positioning surface 41321 may be the inner surface 413311 of the base plate 41331 or the upper surface 413312 of the cylinder 41332 .

[0125] In the present invention, the positioning clamp upper cylinder 41324 and the positioning clamp lower cylinder 41325 are an integrated structure. When in use, the knife 4131 is first inserted into the positioning clamp middle hole 41328, and the upper end of the handle of the knife 4131 is preferably not to exceed the upper cylinder surface 413241. When the knife 4131 is selected, the diameter of the knife 4131 should be slightly larger than the inner diameter of the positioning clamp middle hole 41328, so that there is a pre-tightening force between the knife 4131 and the positioning clamp middle hole 41328. When the spindle grabs the knife 413 through the knife grabbing structure 414, the knife grabbing structure 414 directly grabs the upper cylinder of the positioning clamp upper cylinder 41324, and indirectly grabs the knife 4131.

[0126] Since the knife grasping structure 414 grasps the knife 4131 indirectly instead of directly grasping the handle of the knife 4131 , the knife 4131 will not be damaged, thus extending the service life of the knife 4131 .

[0127] The spindle 411 in the present invention is an ultra-high-speed air-bearing spindle.

[0128] The numerical control device in the present invention includes a hardware printed circuit board, a CRT display, a key box, a paper tape reader, etc. and corresponding software, which is used to input digital part programs and complete the storage of input information, data conversion, interpolation operations and realize various control functions.

[0129] The present invention also has auxiliary devices, which are some necessary supporting components in the present invention to ensure the operation of the CNC machine tool, such as cooling, chip removal, lubrication, lighting, monitoring, etc. It includes hydraulic and pneumatic devices, chip removal devices, exchange workbenches, CNC turntables and CNC dividing heads, as well as tools and monitoring and detection devices.

[0130] The present invention also has programming and other auxiliary equipment, which can be used to program and store parts outside the machine.

[0131] The method of the present invention is suitable for use on a machine tool with a spindle speed of 30,000 revolutions per minute or more. For the machine tool, the spindle speed can reach a speed of 30,000 revolutions per minute or more.

[0132] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An automatic tool changing method for an ultra-high-speed air-floating spindle CNC machine tool, characterized in that: The steps include: S1, send tool change command; S2, the sensor detects whether there is a tool on the spindle, if yes, go to step S3, if not, go to step S4; S3, perform the knife-returning action; S4, perform the knife grabbing action and grab the knife according to the following steps; S5, moving the spindle above the tool holder, the spindle is aligned with the tool pre-installed in the tool holder, the tool comprises a tool and a positioning clamp, the positioning clamp is coaxially positioned on the tool, and the distance from the positioning surface of the positioning clamp of each tool on the tool holder to the tool tip is equal; S6, the Z-axis driving mechanism drives the spindle downward, so that the reference surface of the spindle contacts the positioning surface of the positioning clamp of the tool. At the same time, the spindle cylinder built into the spindle drives the rod downward, so that the lock mouth at the lower end of the drive rod opens, and the upper part of the tool extends into the lock mouth. The spindle disc spring located at the upper part of the drive rod is compressed, and the tool holder elastic body in the tool holder is compressed under the action of the downward force of the tool. Under the action of the reaction force of the tool holder elastic body, the reference surface of the spindle contacts closely with the positioning surface of the positioning clamp. S7, the spindle cylinder is depressurized, the spindle disc spring is stretched to drive the driving rod to rise, the locking jaw follows the driving rod to rise, the locking jaw is retracted to clamp the upper part of the tool, and the reference surface of the spindle and the positioning surface of the positioning clamp are kept in close contact; S8, the Z-axis drive device drives the spindle and the grasped tool to rise synchronously, and the machine enters the processing state.

2. The automatic tool changing method for ultra-high-speed air-floating spindle CNC machine tool according to claim 1, characterized in that: It also includes step S9 and repeating steps S2-S8, thereby realizing the cyclic tool changing function during the machining process.

3. The automatic tool changing method for ultra-high-speed air-floating spindle CNC machine tool according to claim 1 or 2, characterized in that: The S3 step comprises the following steps: S31, move the spindle to the top of the tool holder seat, aligning the spindle with the empty space of the tool holder seat; S32, the Z-axis driving mechanism drives the spindle to move downward, the tool on the spindle moves downward to the set position, the tool holder holds the positioning clamp on the tool, and the spindle stops moving downward; the spindle cylinder in the spindle is inflated, the butterfly spring is pressed downward, the driving rod moves downward, the locking mouth opens, and the locking mouth releases the tool; S33, the spindle moves upward, and the spindle is separated from the tool, completing the tool return.

4. The automatic tool changing method for ultra-high-speed air-floating spindle CNC machine tool according to claim 1 or 2, characterized in that: The step S5 also includes a tool assembly step: S51, placing the knife and the positioning clamp in the special fixture, inserting the knife handle into the center hole of the positioning clamp, making the positioning surface of the positioning clamp close to the upper positioning surface of the special fixture, making the tip of the knife against the lower positioning surface of the special fixture, ensuring that the distance between the positioning surface of the positioning clamp and the tip of the knife of all knives is the same fixed value; S52, fixing the positioning clamp on the tool handle to form a tool.

5. An ultra-high-speed air-bearing spindle CNC machine tool, characterized in that: The tool can be changed using the automatic tool changing method described in any one of claims 1 to 4.

6. An ultra-high-speed air-floating spindle CNC numerically controlled machine tool, comprising a frame (1), a processing table (2) being provided on the frame (1), a tool magazine (3) being provided above the processing table (2), a processing section (4) being provided above the tool magazine (3), the processing section (4) comprising a spindle fixing seat (41), a spindle (411) being vertically provided on the spindle fixing seat (41), the spindle (411) being driven by a Z-direction driving mechanism (412), a tool grabbing structure (414) for grabbing a tool (413) being provided inside the spindle (411), characterized in that: A plurality of cutting tools (413) are stored in the tool magazine (3), each of the cutting tools (413) comprising a cutting tool (4131) and a positioning clamp (4132), the positioning clamp (4132) being coaxially positioned on the cutting tool (4131), and the distance between the positioning surface (41321) of the positioning clamp (4132) of each cutting tool (413) and the cutting tool tip (41311) being equal; after the tool grabbing structure grabs the cutting tool (413), the positioning surface (41321) of the positioning clamp (4132) is in close contact with the reference surface (4111) of the spindle (411).

7. The ultra-high-speed air-bearing spindle CNC machine tool according to claim 6, characterized in that: The knife grabbing structure (414) comprises a main shaft cylinder (4141) arranged in the main shaft (411), a driving rod (4143) connected to the output shaft (4142) of the main shaft cylinder (4141), a butterfly spring (4144) driven by the output shaft (4142) is arranged at the upper end of the driving rod (4143), and a locking mouth (4145) is arranged at the lower end of the driving rod (4143).

8. The ultra-high-speed air-bearing spindle CNC machine tool according to claim 6 or 7, characterized in that: The tool magazine (3) is provided with a plurality of tool clamp seats (31), each tool clamp seat (31) having a clamping portion (311) of a positioning clamp (4132) for holding a tool (413), and a tool clamp seat elastic body (312) located below the clamping portion (311) for pushing the tool (413) upward.

9. The ultra-high-speed air-bearing spindle CNC machine tool according to claim 8, characterized in that: The clamping portion (311) is an elastic clamping portion.

10. The ultra-high-speed air-bearing spindle CNC machine tool according to claim 6 or 7, characterized in that: The positioning clip (4132) is coaxially fixed on the handle of the knife (4131) by means of a fastener or heat shrinkage.

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