Linear motor and machine tool

Abstract

A linear motor (100), which is used in a machine tool, is provided with: a magnet plate (10) in which a plurality of magnets (12) are arranged in a first direction; and a slider (50) in which a plurality of coils (52) are arranged in the first direction, the slider (50) being configured so as to be slidable in the first direction with respect to the magnet plate (10). The slider (50) includes an air supply path (54) for supplying air to a gap between the magnet plate (10) and the slider (50).

Description

Technical Field

[0001] The present disclosure relates to a linear motor and a machine tool. Background Art

[0002] Japanese Patent Application Publication No. 2014-042423 (Patent Document 1) discloses an invention related to a linear motor. This linear motor includes an excitation unit that functions as a stator and an armature that functions as a mover. The armature has a coil inside. When current flows through the coil, the armature generates a driving force due to electromagnetic induction, and the armature moves on the excitation unit.

[0003] The armature has two cooling tubes, arranged one above the other. These two cooling tubes are positioned so as to cool the coil from the side of the armature opposite the side facing the excitation unit. The refrigerant in the upper cooling tube flows in the opposite direction to the refrigerant in the lower cooling tube. This ensures a uniform temperature distribution in the armature in the linear motor disclosed in Patent Document 1.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-042423 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] Heat generated by the coils on the mover side is sometimes transferred to the magnets on the fixed side. When the temperature of the magnets rises, the performance of the linear motor deteriorates. Patent Document 1 does not disclose any method for preventing heat transfer from the coils to the magnets. Therefore, technology that can prevent heat transfer from the coils to the magnets is desired.

[0009] Solutions for solving problems

[0010] In one example of the present disclosure, a linear motor is used in a machine tool. The linear motor includes: a magnet plate having a plurality of magnets arranged in a first direction; and a slider having a plurality of coils arranged in the first direction, the slider being configured to slide relative to the magnet plate in the first direction. The slider includes an air supply path for supplying air to a gap between the magnet plate and the slider.

[0011] In one example of the present disclosure, the air supply path is arranged so as to supply air toward the gap from a second direction parallel to the surface of the magnet plate and perpendicular to the first direction.

[0012] In one example of the present disclosure, the air supply path is arranged to overlap with ends of the plurality of coils in the second direction when viewed from a third direction perpendicular to both the first direction and the second direction.

[0013] In one example of the present disclosure, the air supply path includes a pipe for guiding the air to the gap, and the pipe is held by the slider so as to move together with the slider.

[0014] In one example of the present disclosure, the air supply path is arranged so as to overlap with the plurality of magnets in the second direction when viewed from the second direction.

[0015] In one example of the present disclosure, the slider is formed with a through hole that passes through the slider in a direction perpendicular to the surface of the magnet plate. The through hole functions as the air supply path.

[0016] In one example of the present disclosure, a plurality of the through holes are formed in the slider, and the plurality of the through holes are arranged along the first direction.

[0017] In one example of the present disclosure, the present invention includes: the linear motor; and a spindle for rotatably holding a workpiece or a tool. The linear motor is used to move the spindle.

[0018] In another example of the present disclosure, a machine tool is provided. The machine tool includes: the linear motor; and a table for placing a workpiece. The linear motor is used to drive the table.

[0019] In another example of the present disclosure, a machine tool is provided. The machine tool includes: a linear motor; and a loader for conveying components. The linear motor is used to drive the loader.

[0020] The above objects, features, aspects and advantages and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a perspective view showing the linear motor 100 according to the embodiment from an oblique direction.

[0022] Figure 2 It is a side view showing the linear motor 100 from the Y-axis direction.

[0023] Figure 3 It is along Figure 2 A cross-sectional view taken along line III-III is shown.

[0024] Figure 4 This is a diagram showing the slider 50 from the Z-axis direction.

[0025] Figure 5 It is along Figure 4 A cross-sectional view of the slider 50 is shown along line VV.

[0026] Figure 6 It is along Figure 4 A cross-sectional view of the slider 50 is shown along line VI-VI.

[0027] Figure 7 This is a diagram showing the slider 50 from the Z-axis direction.

[0028] Figure 8 It is along Figure 7 A cross-sectional view of the slider 50 is shown along line VIII-VIII.

[0029] Figure 9 It is along Figure 7 A cross-sectional view of the slider 50 is shown along line IX-IX.

[0030] Figure 10 This is a diagram showing an example of the device configuration of the machine tool 200 .

[0031] Figure 11 This is a diagram showing another example of the device configuration of the machine tool 200 .

[0032] Figure 12 This is a diagram showing another example of the device configuration of the machine tool 200 . DETAILED DESCRIPTION

[0033] Hereinafter, various embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, identical components and elements are denoted by the same reference numerals. Their names and functions are also identical. Therefore, detailed descriptions thereof will not be repeated. In addition, the various embodiments and modifications described below may be optionally combined as appropriate.

[0034] <A. Linear Motor 100>

[0035] First, refer to Figure 1 , an overview of the linear motor 100 will be described. Figure 1 This is a perspective view showing the linear motor 100 according to the embodiment from an oblique direction.

[0036] like Figure 1 As shown, the linear motor 100 includes a magnet plate 10 and a slider 50 .

[0037] The magnet plate 10 functions as a stator. A plurality of magnets 12 are arranged on the magnet plate 10. For ease of explanation, the direction in which the magnets 12 are arranged is also referred to as the X-axis direction (first direction) below. The direction parallel to the surface of the magnet plate 10 and perpendicular to the X-axis direction is also referred to as the Y-axis direction (second direction). The direction perpendicular to both the X-axis direction and the Y-axis direction is also referred to as the Z-axis direction (third direction).

[0038] Each magnet 12 among the plurality of magnets 12 is arranged on the magnet plate 10 at predetermined intervals in the X-axis direction. Each magnet 12 among the magnets 12 is a permanent magnet. Each magnet 12 among the magnets 12 is arranged on the magnet plate 10 in such a manner that the polarity thereof is opposite to that of the adjacent magnets 12. As an example, it is assumed that the surface of one magnet 12 is an N pole and the back surface of the same magnet 12 is an S pole. In this case, the surface of the magnet 12 arranged next to the one magnet 12 is an S pole and the back surface is an N pole.

[0039] The slider 50 functions as a mover. The slider 50 includes a plurality of coils 52. The plurality of coils 52 are arranged in the X-axis direction on the slider 50. Each coil 52 is wound in an oblong shape around a tooth 53 (see FIG. 1 ) formed on the slider 50. Figure 3 ).

[0040] The plurality of coils 52 are provided on the slider 50 so as to face the plurality of magnets 12. In other words, the plurality of coils 52 are provided on the slider 50 so as to overlap with the plurality of magnets 12 when viewed from the Z-axis direction.

[0041] The slider 50 slides on the magnet plate 10 in the X-axis direction by applying a magnetic field to the magnets 12. The magnetic field is generated by applying an AC current to the coils 52. The AC current is supplied by a power supply (not shown) electrically connected to the coils 52, for example.

[0042] <B. Air Supply Path 54>

[0043] Next, refer to Figure 2 and Figure 3 Next, the air supply path 54 provided in the slider 50 will be described. Figure 2 It is a side view showing the linear motor 100 from the Y-axis direction. Figure 3 It is along Figure 2 A cross-sectional view taken along line III-III is shown.

[0044] The linear motor 100 includes an air supply path 54 for supplying air to the gap SP between the magnet plate 10 and the slider 50. The gap SP is a space devoid of objects. In other words, only air exists within the gap SP. Air supplied from the air supply path 54 to the gap SP forms a thermal insulation layer within the gap SP. This prevents heat generated by the coils 52 within the slider 50 from being transferred to the magnet plate 10.

[0045] Furthermore, when the linear motor 100 is used in a machine tool, workpiece chips may enter the gap SP. This chipping may cause performance degradation of the linear motor 100 or damage to the magnet plate 10 and the slider 50. Providing the air supply path 54 in the slider 50 prevents workpiece chips from entering the gap SP.

[0046] Note that the air supplied from the air supply path 54 to the gap SP may contain only one type of gas or may contain a plurality of types of gases.

[0047] In addition, the air supply path 54 can be implemented in any form as long as it is a structure that can supply air to the gap SP. Figure 2 and Figure 3 , an air pipe 54A is shown as an example of the air supply path 54 .

[0048] The air pipe 54A is configured to supply air along the Y-axis toward the gap SP. As a result, the air flows from one side of the gap SP to the other side in the Y-axis direction. This allows workpiece chips that enter the gap SP to be discharged along the short side of the magnet plate 10, preventing these chips from remaining on the magnet plate 10.

[0049] More specifically, the air piping 54A is arranged so as to overlap with the Y-axis end of the coil 52 when viewed from the Z-axis direction. The "end of the coil 52" refers to the coil portion including at least the outermost end of the coil 52 in the Y-axis direction. As an example, the end of the coil 52 refers to the coil portion within a range of a predetermined length measured from the outermost end of the coil 52.

[0050] Furthermore, the air piping 54A is arranged so as to overlap with the end portion of the magnet 12 in the Y-axis direction when viewed from the Z-axis direction. The "end portion of the magnet 12" refers to the portion of the magnet including at least the outermost end portion in the Y-axis direction of the magnet 12. As an example, the end portion of the magnet 12 refers to the portion of the magnet included in a range of a predetermined length from the outermost end portion of the magnet 12.

[0051] Typically, the air pipe 54A is held by the slider 50. As a result, when the slider 50 slides on the magnet plate 10, the air pipe 54A moves together with the slider 50. This allows air to be supplied only to portions that require cooling, thereby reducing power consumption.

[0052] The air pipe 54A is provided with an air outflow port OL. The air outflow port OL is provided in the air pipe 54A so as to face the gap SP. Thus, the air sent into the air pipe 54A is ejected from the outflow port OL toward the gap SP.

[0053] The number of outflow ports OL provided in the air pipe 54A is arbitrary. The air pipe 54A may be provided with one outflow port OL or a plurality of outflow ports OL.

[0054] The air pipe 54A also has an air inlet IL. The inlet IL is connected to an air system (not shown) via piping. The air system comprises, for example, an air compressor and valves. The air system pressurizes air from the inlet IL into the air pipe 54A and ejects the air from the outlet OL.

[0055] In addition, Figure 3 In FIG. 5 , an example in which the cross-sectional shape of the air pipe 54A is circular is shown, but the cross-sectional shape of the air pipe 54A is arbitrary. As an example, the cross-sectional shape may be a polygon or other shapes.

[0056] <C. Slider 50>

[0057] Next, refer to Figures 4 to 6 , the above-mentioned sliding member 50 is further described in detail. Figure 4 This is a diagram showing the slider 50 from the Z-axis direction. Figure 5 It is along Figure 4 A cross-sectional view of the slider 50 is shown along line VV. Figure 6 It is along Figure 4 A cross-sectional view of the slider 50 is shown along line VI-VI.

[0058] The slider 50 has a housing 60 that forms its exterior. The housing 60 is made of, for example, resin. The housing 60 houses the slider core 51, the plurality of coils 52, the air piping 54A, the cooling piping 56, and the fixing member 58.

[0059] The slider core 51 is made of, for example, an electromagnetic steel plate. The teeth 53 are formed on the slider core 51 .

[0060] The teeth 53 include auxiliary teeth 53A, which are located outermost in the X-axis direction and are not wound around the coils 52; and coil teeth 53B, which are located inside the auxiliary teeth 53A and are wound around the coils 52. The coils 52 are wound around the coil teeth 53B in an oblong shape.

[0061] The coil teeth 53B are formed with through-holes H extending in the Y-axis direction. A fixing member 58 is inserted into the through-holes H. The fixing member 58 has a threaded hole formed in the Z-axis direction, and the slider core 51 has a through-hole H formed in the Z-axis direction that communicates with the threaded hole of the fixing member 58.

[0062] The fixing member 58 is made of a different type of member from the slider core 51. For example, the slider core 51 is made of laminated steel plates, while the fixing member 58 is made of a metal other than laminated steel plates. For example, the fixing member 58 may be made of iron or another type of metal.

[0063] The cooling pipe 56 is provided on the upper surface of the slider core 51 (i.e., the surface of the slider core 51 opposite the surface facing the magnet plate 10). More specifically, a plurality of grooves are formed on the upper surface of the slider core 51. The grooves are formed at equal intervals in the X-axis direction. Furthermore, the grooves extend in the Y-axis direction. The cooling pipe 56 is arranged in a serpentine manner along the grooves formed in the upper surface of the slider core 51.

[0064] The cooling pipe 56 has an inlet and an outlet for the refrigerant. The inlet and the outlet are connected to a cooler (not shown). The refrigerant flows from the inlet of the cooling pipe 56 to the outlet of the cooling pipe 56, thereby cooling the sliding member 50. The refrigerant reaching the outlet is sent to the cooler for cooling. Thereafter, the cooled refrigerant is sent to the inlet of the cooling pipe 56 again. In this way, the refrigerant circulates on the upper surface of the sliding member core 51 to dissipate heat from the sliding member 50. The refrigerant is, for example, a liquid including water.

[0065] The cooling pipe 56 is made of, for example, a metal pipe having good thermal conductivity. As an example, the cooling pipe 56 may be made of a copper pipe, an aluminum pipe, or a stainless steel pipe.

[0066] In addition, Figure 5 , the cross-sectional shape of the cooling pipe 56 is circular, but the cross-sectional shape of the cooling pipe 56 is arbitrary. The cross-sectional shape of the cooling pipe 56 may be, for example, polygonal or other shapes.

[0067] <D. Modification>

[0068] Next, refer to Figures 7 to 9 , the air supply path 54 (refer to Figure 2 and Figure 3 ) is described as a modified example. Figure 7 This is a diagram showing the slider 50 from the Z-axis direction. Figure 8 It is along Figure 7 A cross-sectional view of the slider 50 is shown along line VIII-VIII. Figure 9 It is along Figure 7 A cross-sectional view of the slider 50 is shown along line IX-IX.

[0069] In the above Figure 2 and Figure 3 , the air supply path 54 is described as the air pipe 54A. However, the air supply path 54 is not limited to the air pipe 54A and can be implemented by any mechanism that can supply air to the gap SP between the magnet plate 10 and the slider 50. As an example, the air supply path 54 is implemented by a through hole 54B formed in the slider 50.

[0070] The through hole 54B is a hole that passes through the slider 50 in the Y-axis direction. In this modification, air is supplied to the gap SP between the magnet plate 10 and the slider 50 via the through hole 54B. In this way, the through hole 54B functions as an air supply path 54. Air is supplied to the gap SP via the through hole 54B, whereby the air becomes a heat insulating layer in the gap SP. As a result, it is possible to prevent the heat generated by the coil 52 in the slider 50 from being transferred to the magnet plate 10. In addition, there is no need to provide a new structure in the linear motor 100 to prevent heat transfer from the slider 50 to the magnet plate 10.

[0071] More specifically, the through hole 54B is formed in the slider core 51 so as not to overlap with the coil 52, the cooling pipe 56, and the fixing member 58 when viewed from the Z-axis direction. The through hole 54B includes an air inlet IL and an air outlet OL.

[0072] The inlet IL is connected to an air machine (not shown) via a pipe. The air machine is composed of, for example, an air compressor and a valve. The air machine pressurizes air from the inlet IL to the through hole 54B and ejects the air from the outlet OL.

[0073] The outflow port OL is formed in the slider core 51 so as to communicate with the gap SP between the magnet plate 10 and the slider 50. Thus, the air sent into the through-hole 54B is ejected from the outflow port OL toward the gap SP.

[0074] The number of through holes 54B formed in the slider core 51 is arbitrary. The slider core 51 may have one through hole 54B or a plurality of through holes 54B. Figures 7 to 9 In the example shown in FIG. 5 , four through holes 54B are formed in the slider core 51 .

[0075] In one embodiment, the plurality of through holes 54B are formed in the slider core 51 so as to be aligned along the X-axis direction. In this case, the plurality of through holes 54B are preferably formed in the slider core 51 so as to pass through the center line of the slider core 51 in the Y-axis direction.

[0076] In another embodiment, the plurality of through holes 54B are formed in the slider core 51 so as to be aligned along the Y-axis direction. In this case, the plurality of through holes 54B are preferably formed in the slider core 51 so as to pass through the center line of the slider core 51 in the X-axis direction.

[0077] In another embodiment, the through-holes 54B arranged in a row along the Y-axis direction may be arranged in a plurality of rows along the X-axis direction and formed in the slider core 51. In this case, the through-holes 54B are formed at symmetrical positions with respect to the center line of the slider core 51 in the Y-axis direction. Furthermore, the through-holes 54B are formed at symmetrical positions with respect to the center line of the slider core 51 in the X-axis direction.

[0078] <E. Application Examples of Linear Motor 100>

[0079] Next, refer to Figures 10 to 12 Next, an application example of the linear motor 100 will be described. The linear motor 100 can be used, for example, to drive various components in a machine tool.

[0080] The term "machine tool" as used herein encompasses a variety of devices capable of machining workpieces. Machine tool 200 may be a horizontal machining center or a vertical machining center. Alternatively, machine tool 200 may be a lathe, an additive manufacturing machine, or other cutting or grinding machinery.

[0081] When the linear motor 100 is used in a machine tool, the magnet plate 10, functioning as a stator, is mounted on a stationary component within the machine tool. Meanwhile, the slider 50, functioning as a mover, is mounted on a driven component within the machine tool. In this case, a bolt passes through the driven component and engages with a threaded hole formed in the fixing member 58 within the slider 50. This secures the driven component to the slider 50.

[0082] (E1. Spindle)

[0083] First, refer to Figure 10 , an example in which the linear motor 100 is applied to drive a main spindle will be described. Figure 10 This is a diagram showing an example of the device configuration of the machine tool 200 .

[0084] The linear motor 100 is used, for example, to move the position of a spindle 250 that rotatably holds a workpiece or a tool. The spindle 250 may be a workpiece spindle for rotating the workpiece or a tool spindle for rotating the tool.

[0085] For convenience of explanation, the coordinate system based on the main axis 250 is represented by the X' axis, the Y' axis, and the Z' axis. The X' axis, the Y' axis, and the Z' axis are orthogonal to each other.

[0086] like Figure 10 As shown, the machine tool 200 includes a control unit 200A, a drive unit 240A, and a spindle 250 .

[0087] The control unit 200A is, for example, a CNC (Computer Numerical Control) device. A CNC device is comprised of at least one integrated circuit. An integrated circuit may be comprised of, for example, at least one CPU (Central Processing Unit), at least one MPU (Micro Processing Unit), at least one ASIC (Application Specific Integrated Circuit), at least one FPGA (Field Programmable Gate Array), or a combination thereof. The control unit 200A controls the operation of the drive unit 240A by executing various programs, such as machining programs.

[0088] The drive unit 240A is a mechanism for driving the main shaft 250. The device structure of the drive unit 240A is arbitrary. The drive unit 240A can be composed of a single drive unit or a plurality of drive units. Figure 10 In the example of FIG. 1 , the drive unit 240A is composed of motor drivers 241A to 241C, linear motors 242A to 242C, and encoders 243A to 243C. The linear motors 242A to 242C each correspond to the linear motor 100 described above.

[0089] The motor driver 241A controls the driving of the spindle 250 in the X′-axis direction. The motor driver 241A receives an input of a control signal from the control unit 200A and outputs a current corresponding to the control signal to the linear motor 242A.

[0090] More specifically, control unit 200A sequentially outputs control signals containing target positions to motor driver 241A. Motor driver 241A calculates the actual position of spindle 250 based on feedback signals from encoder 243A and supplies current to linear motor 242A to reduce the difference between the actual position and the target position. Consequently, motor driver 241A moves spindle 250 to any desired position in the X'-axis direction.

[0091] The motor driver 241B controls the driving of the spindle 250 in the Y′-axis direction. The motor driver 241B receives an input of a control signal from the control unit 200A and outputs a current corresponding to the control signal to the linear motor 242B.

[0092] More specifically, control unit 200A sequentially outputs control signals containing target positions to motor driver 241B. Motor driver 241B calculates the actual position of spindle 250 based on feedback signals from encoder 243B and supplies current to linear motor 242B to reduce the difference between the actual position and the target position. Consequently, motor driver 241B moves spindle 250 to any desired position in the Y'-axis direction.

[0093] The motor driver 241C controls the driving of the spindle 250 in the Z′-axis direction. The motor driver 241C receives an input of a control signal from the control unit 200A and outputs a current corresponding to the control signal to the linear motor 242C.

[0094] More specifically, control unit 200A sequentially outputs control signals containing target positions to motor driver 241C. Motor driver 241C calculates the actual position of spindle 250 based on feedback signals from encoder 243C and supplies current to linear motor 242C to reduce the difference between the actual position and the target position. Consequently, motor driver 241C moves spindle 250 to any desired position in the Z'-axis direction.

[0095] (E2. Workbench)

[0096] Next, refer to Figure 11 , an example in which the linear motor 100 is applied to drive a worktable will be described. Figure 11 This is a diagram showing another example of the device configuration of the machine tool 200 .

[0097] The linear motor 100 is used, for example, to drive a table 260 provided in a machine tool. The table 260 is a table for placing a workpiece to be processed.

[0098] like Figure 11 As shown, the machine tool 200 includes a control unit 200A, a drive unit 240B, and a table 260 .

[0099] The driving unit 240B is a mechanism for driving the workbench 260. The device structure of the driving unit 240B is arbitrary. The driving unit 240B can be composed of a single driving unit or a plurality of driving units. Figure 11 In the example of FIG. 2 , the drive unit 240B is composed of motor drivers 241D and 241E, linear motors 242D and 242E, and encoders 243D and 243E. The linear motors 242D and 242E each correspond to the linear motor 100 described above.

[0100] The motor driver 241D controls the driving of the table 260 in the X′-axis direction. The motor driver 241D receives an input of a control signal from the control unit 200A and outputs a current corresponding to the control signal to the linear motor 242D.

[0101] More specifically, the control unit 200A sequentially outputs control signals containing target positions to the motor driver 241D. The motor driver 241D calculates the actual position of the worktable 260 based on feedback signals from the encoder 243D and supplies current to the linear motor 242D to reduce the difference between the actual position and the target position. Consequently, the motor driver 241D moves the worktable 260 to any position in the X'-axis direction.

[0102] The motor driver 241E controls the driving of the table 260 in the Y′-axis direction. The motor driver 241E receives an input of a control signal from the control unit 200A and outputs a current corresponding to the control signal to the linear motor 242E.

[0103] More specifically, the control unit 200A sequentially outputs control signals containing target positions to the motor driver 241E. The motor driver 241E calculates the actual position of the worktable 260 based on feedback signals from the encoder 243E and supplies current to the linear motor 242E to reduce the difference between the actual position and the target position. Consequently, the motor driver 241E moves the worktable 260 to any position along the Y' axis.

[0104] (E3. Loader)

[0105] Next, refer to Figure 12 , an example in which the linear motor 100 is applied to driving a loader will be described. Figure 12 This is a diagram showing another example of the device configuration of the machine tool 200 .

[0106] The linear motor 100 is used, for example, to drive a loader 270 for conveying a component, which may be a workpiece before or after processing, or a tool.

[0107] like Figure 12As shown, the machine tool 200 includes a control unit 200A, a drive unit 240C, and a loader 270 .

[0108] The drive unit 240C is a mechanism for driving the loader 270. The device structure of the drive unit 240C is arbitrary. The drive unit 240C can be composed of a single drive unit or a plurality of drive units. Figure 12 In the example of FIG. 2 , the drive unit 240C includes motor drivers 241F, 241G, and 241H, linear motors 242F, 242G, and 242H, and encoders 243F, 243G, and 243H. The linear motors 242F, 242G, and 242H each correspond to the aforementioned linear motor 100 .

[0109] The motor driver 241F controls the driving of the loader 270 in the X′-axis direction. The motor driver 241F receives an input of a control signal from the control unit 200A and outputs a current corresponding to the control signal to the linear motor 242F.

[0110] More specifically, control unit 200A sequentially outputs control signals containing target positions to motor driver 241F. Motor driver 241F calculates the actual position of loader 270 based on feedback signals from encoder 243F and supplies current to linear motor 242F to reduce the difference between the actual position and the target position. Consequently, motor driver 241F moves loader 270 to any desired position in the X'-axis direction.

[0111] The motor driver 241G controls the driving of the loader 270 in the Y′-axis direction. The motor driver 241G receives an input of a control signal from the control unit 200A and outputs a current corresponding to the control signal to the linear motor 242G.

[0112] More specifically, control unit 200A sequentially outputs control signals containing target positions to motor driver 241G. Motor driver 241G calculates the actual position of loader 270 based on feedback signals from encoder 243G and supplies current to linear motor 242G to reduce the difference between the actual position and the target position. Consequently, motor driver 241G moves loader 270 to any desired position in the Y'-axis direction.

[0113] The motor driver 241H controls the driving of the loader 270 in the Z′-axis direction. The motor driver 241H receives an input of a control signal from the control unit 200A and outputs a current corresponding to the control signal to the linear motor 242H.

[0114] More specifically, the control unit 200A sequentially outputs control signals containing target positions to the motor driver 241H. The motor driver 241H calculates the actual position of the loader 270 based on feedback signals from the encoder 243H and supplies current to the linear motor 242H to reduce the difference between the actual position and the target position. Consequently, the motor driver 241H moves the loader 270 to any desired position in the Z'-axis direction.

[0115] The embodiments disclosed herein are to be considered in all respects as illustrative rather than restrictive. The scope of the present invention is indicated by the claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0116] Description of Reference Numerals

[0117] 10. Magnetic plate; 12. Magnet; 50. Slider; 51. Slider core; 52. Coil; 53. Tooth; 53A. Auxiliary tooth; 53B. Coil tooth; 54. Air supply path; 54A. Air piping; 54B. Through hole; 56. Cooling piping; 58. Fixing member; 60. Housing; 100. Linear motor; 200. Machine tool; 200A. Control unit; 240A. Drive unit; 240B. Drive unit; 240C. Drive unit; 241A. Motor driver; 241B. Motor driver; 241C. Motor driver; 241D. Motor driver; 241E. Motor driver Actuator; 241F, motor driver; 241G, motor driver; 241H, motor driver; 242A, linear motor; 242B, linear motor; 242C, linear motor; 242D, linear motor; 242E, linear motor; 242F, linear motor; 242G, linear motor; 242H, linear motor; 243A, encoder; 243B, encoder; 243C, encoder; 243D, encoder; 243E, encoder; 243F, encoder; 243G, encoder; 243H, encoder; 250, spindle; 260, workbench; 270, loader.

Claims

1. A linear motor for a machine tool, wherein: The linear motor has: a magnet plate having a plurality of magnets arranged in a first direction; and a slider having a plurality of coils arranged in the first direction, the slider being configured to be slidable in the first direction relative to the magnetic plate; The slider includes an air supply path for supplying air to a gap between the magnet plate and the slider.

2. The linear motor according to claim 1, wherein: The air supply path is arranged so as to supply air toward the gap from a second direction parallel to the surface of the magnetic plate and perpendicular to the first direction.

3. The linear motor according to claim 2, wherein: The air supply path is arranged so as to overlap with ends of the plurality of coils in the second direction when viewed from a third direction that is orthogonal to both the first direction and the second direction.

4. The linear motor according to claim 3, wherein: The air supply path includes a pipe for guiding the air to the gap. The pipe is held by the slider so as to move together with the slider.

5. The linear motor according to any one of claims 2 to 4, wherein: When viewed from the second direction, the air supply path is arranged so as to overlap with the plurality of magnets in the second direction.

6. The linear motor according to claim 1, wherein The slider is formed with a through hole that penetrates the slider in a direction perpendicular to the surface of the magnet plate. The through hole functions as the air supply path.

7. The linear motor according to claim 6, wherein: A plurality of through holes are formed in the sliding member. The plurality of through holes are arranged along the first direction.

8. A machine tool, wherein: The machine tool has: A linear motor according to any one of claims 1 to 7; and a spindle for rotatably holding a workpiece or a tool, wherein the linear motor is used to move the position of the spindle.

9. A machine tool, wherein: The machine tool has: The linear motor according to any one of claims 1 to 7; and A workbench for placing workpieces. The linear motor is used to drive the workbench.

10. A machine tool, wherein: The machine tool has: The linear motor according to any one of claims 1 to 7; and Loaders for transporting components, The linear motor is used to drive the loader.

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