Spindle of machine tool

Abstract

According to the present invention, a spindle of a machine tool may comprise: a spindle head; a spindle arranged in the spindle head to be tiltable; and a tilting unit, including an operation unit, a first support unit, and a second support unit, for tilting the spindle with respect to a tilting axis by means of a linear movement of the operation unit.

Description

spindle of a machine tool

[0001] The present invention relates to a spindle of a machine tool, and more particularly, to a spindle of a machine tool capable of applying a large rotational torque to the spindle in a miniaturized state and performing precise tilting angle control when performing processing on a material, and particularly to a spindle of a machine tool that performs friction stir welding.

[0002] In general, a machine tool refers to a machine used for the purpose of processing a metal / non-metal workpiece into a desired shape and size using an appropriate tool using various cutting or non-cutting processing methods.

[0003] Various types of machine tools, including turning centers, vertical / horizontal machining centers, gate-type machining centers, Swiss turns, electrical discharge machines, horizontal NC boring machines, CNC lathes, and multi-tasking machines, are widely used in various industrial fields for their respective tasks.

[0004] Among machine tools, a multi-tasking machine (MTM) is a turning center equipped with a multi-functional automatic tool changer (ATC) and a tool magazine, capable of performing a variety of machining operations, including turning, drilling, tapping, and milling. In a multi-tasking machine, the operator manually loads or replaces tools required for machining into the tool magazine.

[0005] Many types of machine tools in use today typically feature control panels utilizing numerical control (NC) or computerized numerical control (CNC) technology. These panels feature various function switches or buttons and a monitor.

[0006] In addition, the machine tool is equipped with a table on which the workpiece material is placed and transferred for processing the workpiece, a pallet for preparing the workpiece before processing, a spindle on which a tool or workpiece is combined and rotates, a tailstock for supporting the workpiece during processing, a vibration damper, etc.

[0007] Typically, in machine tools, the table, tool rest, spindle, tailstock, and oscillation unit are equipped with a transfer unit that moves along the transfer axis to perform various processing operations.

[0008] Additionally, machine tools generally use multiple tools for various processing operations, and tool magazines or turrets are used as tool storage spaces for storing multiple tools.

[0009] These machine tools use multiple tools for various processing tasks, and a tool magazine is used as a tool storage space to store multiple tools.

[0010] Additionally, machine tools are generally equipped with an automatic tool changer (ATC) to retrieve or retract a specific tool from the tool magazine under the command of the numerical control unit in order to improve the productivity of the machine tool.

[0011] Additionally, machine tools are typically equipped with an automatic pallet changer (APC) to minimize downtime. The APC automatically exchanges pallets between the workpiece processing area and the workpiece installation area. Pallets can be loaded with workpieces.

[0012] Additionally, machine tools are generally classified into turning centers and machining centers depending on the processing method.

[0013] Meanwhile, Friction Stir Welding (FSW) refers to a welding process in which a tool is inserted into the materials to be joined while rotating at high speed, heat is generated by the mutual friction between the tool and the materials to be joined, the material around the tool is softened by this frictional heat, and the materials on both sides of the joining surface are forcibly mixed by the plastic flow of the material caused by the stirring of the tool.

[0014] The joining materials for friction stir welding (FSW) are mainly lightweight non-ferrous metals (Al, Cu, etc.).

[0015] Friction stir welding (FSW) of this type has the advantage of being a solid-state weld, free of solidification defects (e.g., pores, high-temperature cracks, softening cracks, etc.) and having high joint strength.

[0016] Friction stir welding (FSW) is a forging-type joining process that requires high axial force, frictional heat generated during processing, and vibration caused by the stirring action when the tool rotates.

[0017] When performing friction stir welding (FSW), if the material and tool are inclined at a predetermined angle, the friction stir welding speed is faster and the friction stir welding quality is better than when using a vertically fixed tool.

[0018] When the tool travel direction (i.e., the friction stir welding travel direction) is a flat straight line, friction stir welding can be performed while initially maintaining the tool inclination angle until the end.

[0019] However, when the tool travel direction (i.e., the friction stir welding travel direction) changes, such as to a curved surface, the initial inclination angle of the tool is not maintained according to the tool travel direction. Therefore, the tool inclination angle must be adjusted according to the tool travel direction to increase the friction stir welding speed and improve the quality of friction stir welding.

[0020] To adjust the tool inclination angle according to the tool travel direction, the spindle of a conventional machine tool can be manually adjusted. However, this has the problem of not promoting continuous processing and automation of friction stir welding and increasing processing time.

[0021] In addition, the spindle of a conventional machine tool requires a rotational torque of 20KN or more due to the inclination angle during friction stir welding, and to achieve this, the size of the spindle increases, making it impossible to miniaturize, and there was a problem that manufacturing cost and time increased.

[0022] Moreover, the spindle of conventional machine tools had a problem in that it could not precisely control the inclination angle during friction stir welding, which resulted in reduced processing precision and consumer dissatisfaction.

[0023] The present invention is intended to solve the above-mentioned problems, and the present invention provides a spindle of a machine tool, which has a tilting unit including an operating unit, a first support unit, and a second support unit, and which tilts the spindle about a tilting axis by linear movement of the operating unit, thereby miniaturizing the tilting unit and applying a large rotational torque to the spindle, and which can perform precise tilting angle control.

[0024] In order to achieve the object of the present invention, the spindle of the machine tool according to the present invention may include a spindle head; a spindle tiltably arranged on the spindle head; and a tilting unit having an operating part, a first support part, and a second support part, and tilting the spindle about a tilting axis by linear movement of the operating part.

[0025] In addition, in another preferred embodiment of the spindle of the machine tool according to the present invention, the operating unit of the tilting unit of the spindle of the machine tool may be extended through the spindle head and the spindle, the first support unit may be arranged on one side of the operating unit so that the center of the first support unit is spaced apart from the center of the tilting axis by a predetermined distance, and the second support unit may be arranged on the other side of the operating unit so that the angle formed by the center of the second support unit, the center of the first support unit, and the center of the tilting axis forms a right angle when the spindle is in an origin state where it is not tilted.

[0026] In addition, in another preferred embodiment of the spindle of the machine tool according to the present invention, when the spindle is tilted by the operation of the operating part of the spindle of the machine tool, only the distance between the center of the first support part and the center of the second support part changes, and the distance between the center of the first support part and the center of the tilting axis can be maintained constant.

[0027] In addition, in another preferred embodiment of the spindle of the machine tool according to the present invention, the operating part of the tilting unit of the spindle of the machine tool may include a motor part that generates rotational power; a ball screw that rotates by the rotational power of the motor part; a moving part that moves linearly along the ball screw in conjunction with the rotation of the ball screw; and a connecting part that is coupled to the spindle head and moves in conjunction with the movement of the moving part.

[0028] In addition, in another preferred embodiment of the spindle of the machine tool according to the present invention, the operating unit of the tilting unit of the spindle of the machine tool may further include a reduction unit installed between the motor unit and the ball screw; and a stopper unit installed at the tip of the ball screw to prevent the moving unit from being detached.

[0029] In addition, in another preferred embodiment of the spindle of the machine tool according to the present invention, the first support part of the tilting unit of the spindle of the machine tool may include a first housing part; a first shaft part arranged inside the first housing part so as to rotate in conjunction with the movement of the moving part; a first bearing that supports the rotation of the first shaft part; and a first preload part arranged outside the first bearing to apply a preload to the first bearing.

[0030] In addition, in another preferred embodiment of the spindle of the machine tool according to the present invention, the second support part of the tilting unit of the spindle of the machine tool may include a second housing part; a second shaft part disposed inside the second housing part so as to rotate in conjunction with the rotation of the ball screw; a second bearing supporting the rotation of the second shaft part; and a second preload part disposed outside the second bearing to apply a preload to the second bearing.

[0031] In addition, in another preferred embodiment of the spindle of the machine tool according to the present invention, the first bearing of the first support part of the tilting unit of the spindle of the machine tool may be formed as a tapered roller bearing.

[0032] In addition, in another preferred embodiment of the spindle of the machine tool according to the present invention, the spindle of the machine tool may further include a clamping unit that clamps the spindle after tilting of the spindle is completed by the tilting unit.

[0033] In addition, in another preferred embodiment of the spindle of the machine tool according to the present invention, the spindle of the machine tool may further include a control unit in which the spindle head is arranged to be rotatable in the axial direction and the spindle head rotates in accordance with the direction of travel of the spindle to match the tilting direction and the direction of travel of the spindle.

[0034] In addition, in another preferred embodiment of the spindle of the machine tool according to the present invention, the spindle of the machine tool can perform friction stir welding.

[0035] The spindle of the machine tool according to the present invention has a tilting unit having an operating portion, a first support portion, and a second support portion, and the operating portion is extended through the spindle head and the spindle, the first support portion is arranged on one side of the operating portion so that the center of the first support portion is spaced apart from the center of the tilting axis by a predetermined distance, and the second support portion is arranged on the other side of the operating portion so that the angle formed by the center of the second support portion, the center of the first support portion, and the center of the tilting axis forms a right angle when the spindle is in the origin state where it is not tilted, thereby enabling a sufficient rotational torque to be stably applied to the spindle in a state where miniaturization is promoted, thereby having the effect of improving processing safety and reliability.

[0036] In addition, the spindle of the machine tool according to the present invention has the effect of improving processing precision and preventing damage to the equipment by precisely controlling the tilting angle by maintaining the distance between the center of the first support part and the center of the second support part constant while only changing the distance between the center of the first support part and the center of the tilting axis when the spindle is tilted by the operation of the operating part.

[0037] Furthermore, the spindle of the machine tool according to the present invention has the effect of maximizing space utilization by miniaturizing the spindle of the machine tool through a structure that converts linear motion into rotary motion by means of a ball screw method, and reducing manufacturing costs, maintenance costs, and time, thereby improving consumer satisfaction.

[0038] Figure 1 shows a front view of the spindle of the machine tool according to the present invention at the origin state.

[0039] Figure 2 shows a side view of the spindle of the machine tool according to the present invention at the origin state.

[0040] Figure 3 shows a conceptual diagram of the arrangement structure of the spindle of the machine tool according to the present invention.

[0041] FIG. 4 shows a cross-sectional view of a tilting unit of a spindle of a machine tool according to the present invention in FIG. 1.

[0042] FIG. 5 shows a cross-sectional view of a tilting unit of a spindle of a machine tool according to the present invention in FIG. 2.

[0043] Figure 6 shows a front view of the spindle of the machine tool according to the present invention when it is tilted to the maximum.

[0044] Fig. 7 shows a side view of the spindle of the machine tool according to the present invention when it is tilted to the maximum.

[0045] FIG. 8 shows a cross-sectional view of the tilting unit of the spindle of the machine tool according to the present invention in FIG. 6.

[0046] FIG. 9 shows a cross-sectional view of the tilting unit of the spindle of the machine tool according to the present invention in FIG. 7.

[0047] Hereinafter, a spindle of a machine tool according to an embodiment of the present invention will be described in detail with reference to drawings. The embodiments introduced below are provided as examples to ensure that the spirit of the present invention can be sufficiently conveyed to those skilled in the art. Therefore, the present invention is not limited to the embodiments described below and may be embodied in other forms. In addition, in the drawings, the size and thickness of the device may be exaggerated for convenience. Like reference numbers represent like elements throughout the specification.

[0048] The advantages and features of the present invention, and the methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms. These embodiments are provided only to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Like reference numerals designate like elements throughout the specification. The sizes and relative sizes of layers and regions in the drawings may be exaggerated for clarity of description.

[0049] The terminology used herein is for the purpose of describing embodiments and is therefore not intended to be limiting of the present invention. In this specification, the singular also includes the plural unless specifically stated otherwise. As used herein, the terms "comprise" and / or "comprising" do not exclude the presence or addition of one or more other components, steps, operations, and / or elements mentioned.

[0050] Fig. 1 is a front view of a spindle of a machine tool according to the present invention at its origin. Fig. 2 is a side view of a spindle of a machine tool according to the present invention at its origin. Fig. 3 is a conceptual diagram of a spindle arrangement structure of a machine tool according to the present invention. Fig. 4 is a cross-sectional view of a tilting unit of a spindle of a machine tool according to the present invention in Fig. 1. Fig. 5 is a cross-sectional view of a tilting unit of a spindle of a machine tool according to the present invention in Fig. 2. Fig. 6 is a front view of a spindle of a machine tool according to the present invention at its maximum tilt. Fig. 7 is a side view of a spindle of a machine tool according to the present invention at its maximum tilt. Fig. 8 is a cross-sectional view of a tilting unit of a tilting unit of a spindle of a machine tool according to the present invention in Fig. 6. Fig. 9 is a cross-sectional view of a tilting unit of a tilting unit of a spindle of a machine tool according to the present invention in Fig. 7.

[0051] The spindle (1) of the machine tool according to the present invention will be described with reference to FIGS. 1 to 9.

[0052] A cutting tool for performing general cutting processing can be mounted on the spindle (1) of the machine tool according to the present invention.

[0053] In addition, a friction stir welding tool for performing friction stir welding can be mounted on the spindle (1) of the machine tool according to the present invention, and accordingly, the spindle of the machine tool according to the preferred embodiment of the present invention can perform friction stir welding.

[0054] Below, the explanation focuses on the case where the spindle performs friction stir welding.

[0055] When performing friction stir welding (FSW), if an inclined tool is used in which the material and tool are at a predetermined inclination angle, the friction stir welding speed increases and the friction stir welding quality also improves.

[0056] When the spindle of the machine tool according to the present invention is applied in the process of performing friction stir welding (FSW), the tilting unit is miniaturized as required when performing friction stir welding, and the spindle is miniaturized overall, thereby maximizing space utilization, and at the same time, the linear motion of the ball screw method can be converted into a tilting rotational motion, thereby applying a large rotational torque to the spindle, and the tilting angle can be precisely controlled to 0.001 degrees or less, thereby maximizing the processing quality.

[0057] As shown in FIGS. 1 to 2 and FIG. 4 and FIG. 9, the spindle (1) of the machine tool according to the present invention includes a spindle head (100), a spindle (200), and a tilting unit (300).

[0058] The spindle head (100) is rotatably mounted on a ram, etc., and provides a space in which the spindle is installed so as to be tilted.

[0059] That is, the spindle head (100) is rotatably mounted on a ram or the like in the axial direction (110).

[0060] A spindle (200) is tiltably positioned on the spindle head.

[0061] The tilting unit (300) has an operating part (310), a first support part (320), and a second support part (330), and tilts the spindle about the tilting axis (210) by linear movement of the operating part.

[0062] The operating part (310) is extended through the spindle head and the spindle.

[0063] The first support part (320) is arranged on one side of the operating part so that the center (B) of the first support part is spaced apart from the center (A) of the tilting axis by a predetermined distance (h).

[0064] The second support part (330) is positioned on the other side of the operating part so that the angle formed by the center (C) of the second support part, the center (B) of the first support part, and the center (A) of the tilting axis forms a right angle when the spindle is in the origin state where it is not tilted.

[0065] In this way, since the tilting unit of the spindle of the machine tool according to the present invention is installed on the spindle and the spindle head so that the operating part, the first support part, and the second support part form a right angle, the tilting unit can be miniaturized, the spindle can be compacted, and space utilization can be maximized, and the manufacturing and maintenance time and cost can be reduced.

[0066] As shown in FIG. 2 and FIG. 7, the spindle (1) of the machine tool according to the present invention further includes a control unit (500).

[0067] The control unit (500) performs control to rotate the spindle head according to the direction of travel of the spindle to match the tilting direction and the direction of travel of the spindle.

[0068] That is, the control unit performs control to first appropriately rotate the spindle head in the axial direction according to the direction of travel (K) of the spindle while the spindle head is positioned so as to be rotatable in the axial direction, thereby matching the tilting direction and the direction of travel of the spindle, thereby preventing collision or damage to the equipment and maximizing the processing quality of friction stir welding.

[0069] Additionally, these control units include NC (numerical control) or CNC (computerized numerical control) and have various numerical control programs built in.

[0070] In addition, although not shown in the drawing, according to a preferred embodiment of the present invention, the control unit includes a main operation unit and a display unit, and the main operation unit includes a screen display program and a data input program according to screen display selection, and performs a function of displaying a software switch on a display screen according to an output of the screen display program, and recognizing the on / off of the software switch to issue an input / output command for machine operation.

[0071] The display unit may include at least one of a liquid crystal display (LCD), a thin film transistor-liquid crystal display (TFT LCD), an organic light-emitting diode (OLED), a flexible display, a 3D display, and an e-ink display.

[0072] In addition, although not necessarily limited thereto, the display unit may be formed in the form of a touch screen and installed on the housing, case, or one side of the machine tool to display various function switches or buttons and various types of information.

[0073] In this way, since the display shows information such as the spindle's direction of travel, tilting angle, and axial rotation angle of the spindle head, the user or operator can check the current operating status and equipment status of the machine tool in real time, thereby preventing collisions or tool damage that may occur in advance, reducing maintenance costs and time, preventing safety accidents, and preparing for sudden accidents through alarms, etc.

[0074] As illustrated in FIGS. 2 and 3, when the spindle is tilted by the operation of the operating part, only the distance (L) between the center (B) of the first support part and the center (C) of the second support part changes, and the distance (h) between the center (B) of the first support part and the center (A) of the tilting axis is maintained constant.

[0075] That is, as illustrated in FIG. 3, when the spindle is tilted at a tilting angle (α) by the operation of the operating part, the distance (L) between the center (B) of the first support part and the center (C) of the second support part increases to the distance (L') between the center (B') of the first support part and the center (C) of the second support part as the center of the first support part moves (B'), but the distance (h) between the center (B) of the first support part and the center (A) of the tilting axis remains constant.

[0076] Accordingly, the spindle's large rotational torque is possible, and through precise tilting angle control, processing precision can be improved and damage to the equipment can be prevented.

[0077] As shown in FIG. 2 and FIG. 7, the spindle (1) of the machine tool according to the present invention includes a clamping unit (400) that clamps the spindle after tilting of the spindle is completed by the tilting unit.

[0078] In this way, when the clamping part completes tilting of the spindle by the tilting unit, the spindle is maintained at the corresponding tilting angle to perform processing stably, thereby improving processing precision, minimizing tool damage, and reducing maintenance costs and time of the operating part.

[0079] As shown in FIGS. 4 to 5 and 8 to 9, the operating part (310) of the spindle (1) of the machine tool according to the present invention includes a motor part (311), a ball screw (312), a moving part (313), a connecting part (314), a reduction part (315), and a stopper part (316).

[0080] The motor unit (311) generates rotational power by a control signal from the control unit. Although not necessarily limited thereto, the motor unit may be formed as a servo motor.

[0081] The ball screw (312) rotates by the rotational power of the above motor unit.

[0082] The moving part (313) moves in a straight line along the ball screw in conjunction with the rotation of the ball screw.

[0083] That is, when the ball screw rotates due to the rotational power of the motor, the moving part moves in a straight line along the ball screw in the direction of rotation of the ball screw.

[0084] The connecting part (314) is coupled to the spindle head and moves in conjunction with the movement of the moving part.

[0085] The reduction unit (315) is installed between the motor unit and the ball screw to reduce the rotational speed of the motor. That is, the ball screw rotates at a reduced speed by the reduction unit.

[0086] The stopper part (316) is detachably installed at the tip of the ball screw to prevent the moving part from coming off.

[0087] As illustrated in FIGS. 4 to 5 and 8 to 9, the first support portion (320) of the spindle (1) of the machine tool according to the present invention includes a first housing portion (321), a first shaft portion (322), a first bearing (323), and a first preload portion (324).

[0088] The first housing part (321) forms the outer shape of the first support part.

[0089] The first shaft portion (322) is positioned inside the first housing portion so as to rotate in conjunction with the movement of the moving portion.

[0090] The first bearing (323) supports the rotation of the first shaft portion.

[0091] According to one embodiment of the present invention, the first bearing is formed as a tapered roller bearing.

[0092] Since the first bearing is formed as a tapered roller bearing, it can support the rotation of the first shaft portion while withstanding sufficient radial load.

[0093] The first preload member (324) is arranged on the outside of the first bearing to apply preload to the first bearing and fix the first bearing.

[0094] That is, the first preload unit fixes the first bearing while applying preload to the outer ring portion of the first bearing using a nut structure.

[0095] As illustrated in FIGS. 4 to 5 and 8 to 9, the second support portion (330) of the spindle (1) of the machine tool according to the present invention includes a second housing portion (331), a second shaft portion (332), a second bearing (333), and a second preload portion (334).

[0096] The second housing part (331) forms the outer shape of the second support part.

[0097] The second shaft portion (332) is positioned inside the second housing portion so as to rotate in conjunction with the rotation of the ball screw.

[0098] The second bearing (333) supports the rotation of the second shaft portion.

[0099] The second preload member (334) is arranged on the outside of the second bearing and applies preload to the second bearing.

[0100] That is, the second preloading part fixes the second bearing while applying preload to the outer ring portion of the second bearing using a nut structure.

[0101] In this way, the spindle of the machine tool according to the present invention has the effect of maximizing space utilization by miniaturizing the spindle of the machine tool through a structure that converts linear motion into rotary motion by means of a ball screw method, and reducing manufacturing costs, maintenance costs, and time, thereby improving consumer satisfaction.

[0102] The tilting principle of the spindle of the machine tool according to the present invention is explained with reference to FIGS. 1 to 9.

[0103] As described above, the spindle (1) of the machine tool according to the present invention may be equipped with a cutting tool for performing general cutting processing, but may also be equipped with a friction stir welding tool for performing friction stir welding. Since tilting is relatively more important when performing friction stir welding, the following description will focus on a case where the spindle of the machine tool performs friction stir welding.

[0104] As shown in Fig. 3, friction stir welding is a forging-type joining process that requires a high axial force (Fz), and although the axial force (Fz) varies depending on the joining material, welding thickness, or spindle rotation speed, generally, an axial force of at least 20 KN is required for friction stir welding.

[0105] In addition, as friction stir welding is performed and the spindle moves in the direction of movement (K) to soften the solid material (W) with frictional heat, a horizontal force (Fx) opposite to the direction of movement (K) of the spindle is required that is approximately 30 to 50% of the axial force (Fz).

[0106] In this way, in order to perform friction stir welding in Fig. 3, the rotational torque applied to the center (A) of the tilting axis of the spindle becomes very large.

[0107] That is, for example, in Fig. 3, when the tilting angle (α) is 5 degrees, the distance from the tilting axis center (A) to the tip of the spindle is 150 mm, and the tool length is only 160 mm, the rotational torque applied to the tilting axis center (A) becomes very large at 3,609 Nm.

[0108] In this way, since the tilting axis center requires a large rotational torque, a large gear and motor are required. However, in this case, the tilting axis rotation radius becomes large, which makes it impossible to miniaturize the equipment, increases manufacturing costs, and increases the weight of the tilting unit, which also reduces processing precision.

[0109] To this end, the spindle of the machine tool according to the present invention, as shown in FIGS. 2 to 3 and FIGS. 7 to 8, has a tilting unit including an operating unit, a first support unit, and a second support unit, and operates in a manner in which the linear movement of the ball screw of the operating unit is converted into a rotational movement for tilting while these are arranged at a predetermined position, thereby tilting around the spindle tilting axis by the linear movement of the operating unit.

[0110] That is, as illustrated in FIGS. 2 and 3, the operating part is installed to extend through the spindle head and the spindle, the first support part is installed on one side of the operating part so that the center (B) of the first support part is spaced apart from the center (A) of the tilting axis by a predetermined distance (h), and the second support part is installed on the other side of the operating part so that the angle formed by the center (C) of the second support part, the center (B) of the first support part, and the center (A) of the tilting axis forms a right angle when the spindle is in the origin state where it is not tilted, and the center (C) of the second support part and the center (B) of the first support part are spaced apart by a predetermined length (L).

[0111] In order to perform friction stir welding with a spindle with the tilting unit installed in this way, the spindle must be tilted at a predetermined tilting angle (α) to form a welding angle.

[0112] At this time, when the spindle moves in the right direction (K) in Fig. 3 while friction stir welding the material (W) while tilting at a tilting angle (α), a large axial force (Fz) is applied to the spindle, but the tilting unit of the present invention can support not only precise tilting angle control but also large rotational torque.

[0113] In order to process a material through friction stir welding using a spindle, the spindle is tilted at a tilting angle (α) around the tilting axis center (A) by the operation of the operating part.

[0114] At this time, when the operating part tilts the spindle at a tilting angle (α) about the tilting axis center (A), only the distance (L) between the center (B) of the first support part and the center (C) of the second support part changes, and the distance (h) between the center (B) of the first support part and the center (A) of the tilting axis remains constant.

[0115] Specifically, as illustrated in FIG. 3, when the spindle is tilted at a tilting angle (α) by the operation of the operating part, the distance (L) between the center (B) of the first support part and the center (C) of the second support part is longer as the center of the first support part moves to another point (B') along with the linear movement of the ball screw, but the distance (L') between the center (B) of the first support part and the center (A) of the tilting axis is maintained constant, so that the spindle is tilted at a tilting angle (α) with respect to the center (A) of the tilting axis.

[0116] In this way, the spindle of the machine tool according to the invention is miniaturized by arranging the operating part of the tilting unit, the first support part, and the second support part in an optimal state, and the spindle of the machine tool is tilted around the tilting axis by a structure that converts linear motion into rotational motion by a ball screw method, thereby miniaturizing the spindle of the machine tool, thereby maximizing space utilization, and reducing manufacturing cost, maintenance cost, and time, thereby improving consumer satisfaction.

[0117] Although the detailed description of the present invention described above has been described with reference to preferred embodiments of the present invention, it will be understood by those skilled in the art or having ordinary knowledge in the art that various modifications and changes can be made to the present invention without departing from the spirit and technical scope of the present invention as set forth in the claims below. Accordingly, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

[0118] <Explanation of symbols>

[0119] 1: Spindle of a machine tool

[0120] 100: Spindle head

[0121] 200: Spindle

[0122] 300: Tilting unit

[0123] 400: Clamping section

[0124] 500: Control Unit

Claims

1. Spindle head; a spindle tiltably arranged on the spindle head; and A spindle of a machine tool, characterized by comprising an operating part, a first support part, and a second support part, and including a tilting unit that tilts the spindle about a tilting axis by linear movement of the operating part.

2. In paragraph 1, The above operating part is arranged to extend through the spindle head and the spindle, The first support part is arranged on one side of the operating part so that the center of the first support part is spaced apart from the center of the tilting axis by a predetermined distance, A spindle of a machine tool, characterized in that the second support part is arranged on the other side of the operating part so that the angle formed by the center of the second support part, the center of the first support part, and the center of the tilting axis forms a right angle when the spindle is in a non-tilted origin state.

3. In paragraph 2, A spindle of a machine tool, characterized in that when the spindle is tilted by the operation of the operating part, only the distance between the center of the first support part and the center of the second support part changes, and the distance between the center of the first support part and the center of the tilting axis is maintained constant.

4. In paragraph 3, The above operating part is, A motor section that generates rotational power; A ball screw that rotates by the rotational power of the above motor unit; A moving part that moves in a straight line along the ball screw in conjunction with the rotation of the ball screw; A spindle of a machine tool, characterized in that it includes a connecting part that is coupled to the spindle head and moves in conjunction with the movement of the moving part.

5. In paragraph 4, The above operating part is, A reduction unit installed between the motor unit and the ball screw; and A spindle of a machine tool, characterized in that it further includes a stopper part installed at the tip of the ball screw to prevent the moving part from coming off.

6. In paragraph 4, The above first support part, 1st Housing Division; A first shaft portion arranged inside the first housing portion so as to rotate in conjunction with the movement of the moving portion; A first bearing supporting the rotation of the first shaft portion; and A spindle of a machine tool, characterized in that it includes a first preloading part arranged on the outside of the first bearing and applying preload to the first bearing.

7. In paragraph 4, The above second support part, Second Housing Division; A second shaft portion disposed inside the second housing portion so as to rotate in conjunction with the rotation of the ball screw; A second bearing supporting the rotation of the second shaft portion; and A spindle of a machine tool, characterized in that it includes a second preloading part arranged on the outside of the second bearing and applying preload to the second bearing.

8. In paragraph 6, A spindle of a machine tool, characterized in that the first bearing is formed as a tapered roller bearing.

9. In paragraph 3, A spindle of a machine tool, characterized in that it further includes a clamping unit that clamps the spindle after tilting of the spindle is completed by the tilting unit.

10. In paragraph 1, A spindle of a machine tool, characterized in that the spindle head is arranged to be rotatable in the axial direction, and includes a control unit that rotates the spindle head according to the direction of travel of the spindle to match the tilting direction and the direction of travel of the spindle.

11. In paragraph 1, A spindle of a machine tool characterized in that the spindle performs friction stir welding.

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