Linear motors and machine tools

Abstract

The linear motor (100) includes a magnet plate (10) on which a plurality of magnets (12) are arranged in a first direction, a slider (50) configured to be slidable in the first direction relative to the magnet plate (10), and a cooling pipe (56) provided on a surface of the slider (50) opposite to the side facing the magnet plate (10). Grooves (G) and ridges (R) are alternately formed on the surface in the first direction. Each groove (G) extends in a second direction that is parallel to the surface of the magnet plate (10) and perpendicular to the first direction. Each ridge (R) extends in the second direction. The cooling pipe (56) is installed on the slider (50) so as to snake through each groove (G). On at least one side in the second direction, the entire first end (E1) of each protrusion (R), or a part of the first end (E1) excluding the center of the first end (E1) in the first direction, is located inside both end surfaces of the slider (50) in the second direction.

Description

Technical Field

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

Background Art

[0002] Japanese Patent Application Laid-Open No. 2014-042423 (Patent Document 1) discloses an invention related to a linear motor. The linear motor includes a field part that functions as a stator and an armature that functions as a mover. The armature has a core, a coil, and a cooling pipe. The armature generates a driving force associated with electromagnetic induction by passing a current through the coil and moves on the field part.

[0003] The core is a member that forms the main body of the armature. A plurality of accommodation holes penetrating in the short-side direction are formed inside the core. The cooling pipe is piped so as to meander through each accommodation hole. As a result, the cooling pipe protrudes from the core in the short-side direction.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When the cooling pipe largely protrudes from the core in the short-side direction, the size of the linear motor in the short-side direction increases. Therefore, a technique for making the size of the linear motor in the short-side direction smaller is desired.

Means for Solving the Problems

[0006] One example of the present disclosure provides a linear motor for use in a machine tool. The linear motor comprises a magnet plate on which a plurality of magnets are arranged in a first direction, a slider on which a plurality of coils are arranged in the first direction and configured to slide relative to the magnet plate in the first direction, and a cooling pipe provided on the surface of the slider on the side opposite to the side facing the magnet plate. Grooves and ridges are alternately formed on the surface in the first direction. Each of the plurality of grooves extends in a second direction parallel to the surface of the magnet plate and perpendicular to the first direction. Each of the plurality of ridges extends in the second direction. The cooling pipe is routed to the slider so as to meander through the plurality of grooves. If the end of each of the multiple protrusions in the second direction described above that is aligned with the bent portion of the cooling pipe is defined as the first end, then in at least one side of the second direction, the entire first end, or a portion of the first end excluding the central part of the first end in the first direction, is located inward from both end faces of the slider in the second direction.

[0007] In one example of this disclosure, on both sides in the second direction, the entirety of the first end, or a portion of the first end excluding the central part of the first end in the first direction, is located inward from the end faces.

[0008] In one example of this disclosure, if the end of the above-mentioned ends that is not along the bent portion of the cooling pipe is designated as the second end, then the second end is located in the same position as either of the above-mentioned end faces when viewed from a third direction that is perpendicular to both the first and second directions.

[0009] In one example of this disclosure, each bend in the cooling pipe is located outside the end faces when viewed from a third direction that is perpendicular to both the first and second directions.

[0010] In one example of this disclosure, when viewed from a third direction perpendicular to both the first and second directions, the end of the cooling pipe in the second direction overlaps with the ends of the plurality of coils in the second direction.

[0011] In one example of this disclosure, the width of the cooling pipe in the second direction is longer than the width of each of the plurality of coils in the second direction.

[0012] Another example of the present disclosure provides a machine tool comprising the linear motor and a spindle for rotatably holding a workpiece or tool. The linear motor is used to move the position of the spindle.

[0013] Another example of this disclosure provides a machine tool comprising the linear motor and a table for placing a workpiece. The linear motor is used to drive the table.

[0014] Another example of this disclosure provides a machine tool comprising the linear motor and a loader for transporting a workpiece. The linear motor is used to drive the loader.

[0015] The above and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description relating to the invention, which will be understood in conjunction with the accompanying drawings. [Brief explanation of the drawing]

[0016] [Figure 1] This is a perspective view showing a linear motor according to an embodiment, viewed from an oblique direction. [Figure 2] This diagram shows the slider from the Z-axis perspective. [Figure 3] Figure 2 shows a cross-sectional view of the slider along the line III-III. [Figure 4] Figure 2 shows a cross-sectional view of the slider along the line IV-IV. [Figure 5] This diagram shows the slider core from the Z-axis direction. [Figure 6] Figure 5 shows a cross-sectional view of the slider core along the line VI-VI. [Figure 7] It is a cross-sectional view of the slider core along the line VII-VII shown in FIG. 5. [Figure 8] It is a diagram showing cooling pipes provided for the slider core shown in FIGS. 5 to 7. [Figure 9] It is a diagram showing cooling pipes provided for the slider core according to the comparative example. [Figure 10] It is a diagram showing the slider core according to Modification 1 from the Z-axis direction. [Figure 11] It is a diagram showing the slider core according to Modification 2 from the Z-axis direction. [Figure 12] It is a diagram showing the slider core according to Modification 3 from the Z-axis direction. [Figure 13] It is a diagram showing the cooling pipe from the Z-axis direction. [Figure 14] It is a diagram showing one coil wound around the teeth from the Z-axis direction. [Figure 15] It is a diagram showing an example of the device configuration of a machine tool. [Figure 16] It is a diagram showing another example of the device configuration of a machine tool. [Figure 17] It is a diagram showing another example of the device configuration of a machine tool.

Embodiments for Carrying Out the Invention

[0017] Hereinafter, each embodiment according to the present invention will be described while referring to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated. In addition, each embodiment and each modification described below may be selectively combined as appropriate.

[0018] <A. Linear Motor 100> First, referring to FIG. 1, the outline of the linear motor 100 will be described. FIG. 1 is a perspective view showing the linear motor 100 according to the embodiment from an oblique direction.

[0019] As shown in Figure 1, the linear motor 100 includes a magnet plate 10 and a slider 50.

[0020] The magnetic plate 10 functions as a stator. Multiple magnets 12 are arranged on the magnetic plate 10. For the sake of explanation, the direction in which the magnets 12 are arranged will also be referred to as the X-axis direction (first direction). The direction parallel to the surface of the magnetic plate 10 and perpendicular to the X-axis direction will also be referred to as the Y-axis direction (second direction). The direction perpendicular to both the X-axis direction and the Y-axis direction will also be referred to as the Z-axis direction (third direction).

[0021] Each of the multiple magnets 12 is arranged on the magnet plate 10 at a predetermined interval in the X-axis direction. Each of the magnets 12 is a permanent magnet. Each of the magnets 12 is placed on the magnet plate 10 such that its polarity is opposite to that of adjacent magnets 12. For example, suppose the surface of one magnet 12 is the north pole and the back surface of that magnet 12 is the south pole. In this case, the magnet 12 placed next to that magnet 12 will have its surface as the south pole and its back surface as the north pole.

[0022] The slider 50 functions as a movable element. The slider 50 has a plurality of coils 52. The plurality of coils 52 are arranged in the X-axis direction and provided on the slider 50. Each of the coils 52 is wound in an oval shape around a tooth 53 (see Figure 3), which will be described later and is formed on the slider 50.

[0023] Multiple coils 52 are provided on the slider 50 so as to face multiple magnets 12. In other words, multiple coils 52 are provided on the slider 50 so as to overlap with multiple magnets 12 when viewed from the Z-axis direction.

[0024] The slider 50 receives thrust by applying an alternating current to multiple coils 52, which generates a magnetic field that acts on multiple magnets 12, causing it to slide along the magnet plate 10 in the X-axis direction. The alternating current is supplied, for example, from a power source (not shown) electrically connected to the coils 52.

[0025] <B.スライダ50> Next, the slider 50 described above will be explained in more detail with reference to Figures 2 to 4. Figure 2 is a view of the slider 50 from the Z-axis direction. Figure 3 is a cross-sectional view of the slider 50 along the line III-III shown in Figure 2. Figure 4 is a cross-sectional view of the slider 50 along the line IV-IV shown in Figure 2.

[0026] The slider 50 has a housing 60 that forms its external appearance. The housing 60 is made of, for example, resin. Inside the housing 60 are a slider core 51, a plurality of coils 52, cooling pipes 56, and fixing members 58.

[0027] The slider core 51 is made of, for example, electrical steel sheet. The slider core 51 also has multiple teeth 53 formed on it.

[0028] Each of the teeth 53 protrudes toward the magnet plate 10 from the lower surface of the slider core 51 (i.e., the surface facing the magnet plate 10). In other words, the multiple teeth 53 are facing the aforementioned magnet plate 10 and are formed on the slider core 51 so as to overlap with the magnet plate 10 when viewed from the Z-axis direction. Furthermore, each of the teeth 53 extends in the Y-axis direction.

[0029] The teeth 53 include an auxiliary tooth 53A, which is the outermost tooth in the X-axis direction and does not have the coil 52 wound around it, and a coil tooth 53B, which is located inside the auxiliary tooth 53A and has the coil 52 wound around it. The coil tooth 53B has the coil 52 wound in an oval shape.

[0030] The coil teeth 53B have 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 screw holes in the Z-axis direction, and the slider core 51 has through holes H that communicate with the screw holes of the fixing member 58 in the Z-axis direction.

[0031] The shape of the fixing member 58 is arbitrary. For example, the fixing member 58 may be a rectangular prism, a cylindrical shape, or any other shape.

[0032] The fixing member 58 is made of a different type of material than the slider core 51. For example, while the slider core 51 is made of laminated steel plate, the fixing member 58 is made of a metal other than laminated steel plate. For example, the fixing member 58 may be made of iron or of another type of metal.

[0033] The cooling pipe 56 is provided on the side opposite to the side facing the magnet plate 10. The cooling pipe 56 has a refrigerant inlet and a refrigerant outlet. The inlet and 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, cooling the slider 50. The refrigerant that reaches the outlet is sent to the cooler and cooled. After that, the cooled refrigerant is sent back to the inlet of the cooling pipe 56. In this way, the refrigerant dissipates heat from the slider 50 by circulating over the upper surface of the slider core 51. The refrigerant is a liquid, such as water.

[0034] The cooling pipe 56 is made of, for example, a metal pipe with good thermal conductivity. For example, the cooling pipe 56 may be made of copper pipe, aluminum pipe, or stainless steel pipe.

[0035] Although Figure 3 shows an example where the cross-sectional shape of the cooling pipe 56 is circular, the cross-sectional shape of the cooling pipe 56 is arbitrary. The cross-sectional shape of the cooling pipe 56 may be, for example, a polygon or any other shape.

[0036] <C.スライダコア51> Next, the slider core 51 described above will be explained in more detail with reference to Figures 5 to 9. Figure 5 is a view of the slider core 51 from the Z-axis direction. Figure 6 is a cross-sectional view of the slider core 51 along the line VI-VI shown in Figure 5. Figure 7 is a cross-sectional view of the slider core 51 along the line VII-VII shown in Figure 5.

[0037] On the surface of the slider core 51 opposite to the side facing the magnet plate 10, grooves G and protrusions R are alternately formed in the X-axis direction.

[0038] Each groove G is formed at equal intervals in the X-axis direction. Each groove G also extends in the Y-axis direction. The cooling pipe 56 described above is routed so as to meander through each groove G. The length of each groove G in the Y-axis direction is the same as the length of the slider core 51 in the Y-axis direction. In other words, both ends of the groove G in the Y-axis direction are at the same position as the end faces of the slider core 51 in the Y-axis direction when viewed from the Z-axis direction.

[0039] Although Figure 7 shows an example where the cross-sectional shape of groove G is a semicircle, the cross-sectional shape of groove G is arbitrary. For example, the cross-sectional shape may be a polygon or any other shape.

[0040] Each ridge R is formed at equal intervals in the X-axis direction. Each ridge R also extends in the Y-axis direction. Furthermore, each ridge R protrudes from the slider core 51 on the side opposite to the side facing the magnet plate 10. Two adjacent ridges R form one groove G.

[0041] In the following, the end of each projection R in the Y-axis direction that is aligned with the bent portion of the cooling pipe 56 will also be referred to as "end E1". The bent portion of the cooling pipe 56 represents the U-shaped section of the pipe that is bent from one side to the other in the Y-axis direction. The end of each projection R in the Y-axis direction that is not aligned with the bent portion of the cooling pipe 56 will also be referred to as "end E2". Since the cooling pipe 56 is arranged to meander along the groove G, ends E1 and E2 appear alternately in the X-axis direction.

[0042] In this embodiment, the end E1 of each projection R is located inside the end faces of the slider 50 in the Y-axis direction. In the example shown in Figure 5, each end E1 is located at a distance "ΔD" from the end face of the slider 50. As a result, the bent portion of the cooling pipe 56 can be routed further inside the slider core 51. Consequently, the width of the cooling pipe 56 in the Y-axis direction is reduced, and the size of the linear motor 100 in the Y-axis direction is reduced.

[0043] Figure 8 shows a slider core 51 with cooling pipes 56 provided, as shown in Figures 5 to 7. Figure 9 shows a slider core 51X with cooling pipes 56 provided, as shown in a comparative example.

[0044] Referring to Figure 8, when the cooling pipe 56 is routed to the slider core 51, which has a shaved end of the protrusion R, the bent portion of the cooling pipe 56 can be routed further inward from the slider core 51. As a result, the width of the linear motor 100 in the Y-axis direction becomes "ΔY1".

[0045] Referring to Figure 9, when the cooling pipe 56 is routed to the slider core 51X where the end of the protrusion R is not machined, the bent portion of the cooling pipe 56 protrudes significantly from both end faces of the slider core 51X in the Y-axis direction. As a result, the size of the linear motor 100 in the Y-axis direction becomes "ΔY0". The width "ΔY0" shown in Figure 9 is larger than the width "ΔY1" shown in Figure 8.

[0046] In this way, the end E1 on the side along which the bend of the cooling pipe 56 is aligned is formed inside the slider core 51, thereby reducing the width of the cooling pipe 56 in the Y-axis direction. As a result, the size of the linear motor 100 in the Y-axis direction is reduced.

[0047] On the other hand, the end E2 of the ridge R on the side not along the bent portion of the cooling pipe 56 may or may not be shaved. In the examples of FIGS. 5 to 8, the end E2 is not shaved. In this case, the end E2 of the ridge R is at the same position as either one of the both end faces of the slider core 51 in the Y-axis direction when viewed from the X-axis direction. In other words, the end E2 constitutes the same plane as the end face of the slider core 51 in the Y-axis direction. By adopting a configuration in which only one end of the ridge R is shaved, the cutting portion is reduced.

[0048] Preferably, the cooling pipe 56 is miniaturized in the Y-axis direction within a range where the cooling effect of the coil 52 can be maintained. As an example, the cooling pipe 56 is piped such that its bent portion is located outside both end faces of the slider core 51 in the Y-axis direction. In other words, each bent portion of the cooling pipe 56 is piped so as to protrude from the slider core 51 in the Y-axis direction. In this case, the cooling pipe 56 is piped such that the outer peripheral surface of its bent portion is located outside the both end faces, and the inner peripheral surface of its bent portion is located inside the both end faces.

[0049] Also, the coil 52 is provided such that its end portion is located outside both end faces of the slider core 51 in the Y-axis direction. In other words, the coil 52 is provided on the slider core 51 so as to protrude from the slider core 51 in the Y-axis direction. The end portion (i.e., the bent portion) of the cooling pipe 56 in the Y-axis direction overlaps with the end portion of the coil 5 in the Y-axis direction when viewed from the Z-axis direction. Thereby, the cooling pipe 56 can cool including the end portion of the coil 52. As a result, the deterioration of the performance of the linear motor 100 due to the generated heat is suppressed.

[0050] <D. Modified Example 1> Next, referring to FIG. 10, a modified example of the above-described slider core 51 will be described. FIG. 10 is a view showing a slider core 51A according to Modified Example 1 from the Z-axis direction.

[0051] In the ridge R shown in FIG. 5 above, the end E1 was located inside both end faces of the slider core 51A on both sides in the Y-axis direction. In contrast, in the slider core 51A according to this modification, the end E1 is located inside both end faces of the slider core 51A only on one side in the Y-axis direction.

[0052] Even in such a case, the bent portion on one side of the cooling pipe 56 can be piped more inside the slider core 51, and the size of the linear motor 100 in the Y-axis direction becomes smaller.

[0053] <E. Modification 2> Next, referring to FIG. 11, a further modification of the above-described slider core 51 will be described. FIG. 11 is a view showing the slider core 51B according to Modification 2 from the Z-axis direction.

[0054] In the ridge R shown in FIG. 5 above, the end E2 on the side where the bent portion of the cooling pipe 56 does not run was not cut off. In contrast, in the slider core 51B according to this modification, the end E2 of the ridge R is cut off.

[0055] More specifically, the end E2 of each ridge R is located inside both end faces of the slider 50 in the Y-axis direction. Preferably, the distance “ΔD” from the end face of the slider core 51B to the end E2 is equal to the distance “ΔD” from the end face of the slider core 51B to the end E1. Thereby, the shape of the slider core 51B becomes substantially symmetric with respect to the X-axis. As a result, the operation of the linear motor 100 becomes stable.

[0056] <F. Modification 3> Next, referring to FIG. 12, a further modification of the above-described slider core 51 will be described. FIG. 12 is a view showing the slider core 51C according to Modification 3 from the Z-axis direction.

[0057] In the rib R shown in FIG. 5 above, the entire end portion E1 was located inside both end faces of the slider core 51 in the Y-axis direction. In contrast, in the slider core 51C according to this modification, only a part of the end portion E1 in the X-axis direction is located inside both end faces.

[0058] More specifically, the central portion of the end portion E1 in the X-axis direction is at the same position as the end face of the slider core 51 in the Y-axis direction when viewed from the Z-axis direction. That is, the central portion constitutes the same plane as the end face of the slider core 51 in the Y-axis direction. On the other hand, the remaining portion of the end portion E1 excluding the central portion is located inside both end faces of the slider core 51 in the Y-axis direction.

[0059] Thus, even when the portion other than the central portion of the end portion E1 is cut off, the bent portion of the cooling pipe 56 can be made more inside the slider core 51. As a result, the size of the linear motor 100 in the Y-axis direction becomes smaller.

[0060] As an example, the end portion E1 is chamfered. Preferably, the end portion E1 is R-chamfered such that its outer peripheral surface follows the inner peripheral surface of the bent portion of the cooling pipe 56.

[0061] Note that the chamfering method of the end portion E1 is not limited to R-chamfering, and other chamfering methods may be adopted. As an example, the end portion E1 may be C-chamfered.

[0062] Also, in FIG. 12, an example where the central portion of the end portion E1 constitutes the same plane as the end face of the slider core 51 has been described. However, the entire chamfered end portion E1 may be located inside both end faces of the slider core 51 in the Y-axis direction.

[0063] <G. Preferred amount of cutting> As described above, the end portion E1 of each rib R is cut by a distance “ΔD” (see FIG. 5) from the end face so as to be located inside both end faces of the slider 50 in the Y-axis direction. Hereinafter, the preferred value of the distance “ΔD” will be described with reference to FIGS. 13 and 14.

[0064] Figure 13 shows the cooling pipe 56 as described above, viewed from the Z-axis direction. Figure 14 shows one coil 52 wound around the teeth 53, viewed from the Z-axis direction.

[0065] As shown in Figure 13, let "S" be the length of the straight portion of the cooling pipe 56 in the Y-axis direction. Let "X" be the length of the cooling pipe 56 outside of this straight portion. In this case, the total length of the cooling pipe 56 in the Y-axis direction is "S + X".

[0066] As shown in Figure 14, the length of the slider core 51 in the Y-axis direction is denoted as "L". "L" corresponds to the stacked thickness of the slider core 51. Also, the distance between the teeth 53 and the coil 52 in the Y-axis direction is denoted as "E". Furthermore, the length of the slider core 51 in the Y-axis direction is denoted as "L". Furthermore, the width of the end of the coil 52 in the Y-axis direction is denoted as "A".

[0067] In order for the cooling pipe 56 to sufficiently cool the coil 52, it is preferable that the width of the cooling pipe 56 in the Y-axis direction is longer than the width of the coil 52 in the Y-axis direction. Therefore, it is preferable that the total length "S+X" of the cooling pipe 56 in the Y-axis direction satisfies the following equation (1).

[0068] S+X≧L+2(A+E)···(1) Furthermore, the aforementioned distance "ΔD," which corresponds to the amount of material removed from the protrusion R, is expressed by the following equation (2).

[0069] ΔD = (LS) / 2 ···(2) From equations (1) and (2) above, it is preferable that the distance "ΔD" satisfies the following equation (3).

[0070] ΔD = (LS) / 2 ≤ X / 2 - AE···(3) As a result, the width of the cooling pipe 56 in the Y-axis direction becomes longer than the respective widths of the coils 52 in the Y-axis direction. Also, the cooling pipe 56 becomes shorter by the distance “ΔD” in the Y-axis direction. As a result, while the cooling effect of the coil 52 by the cooling pipe 56 is maintained, the size of the linear motor 100 in the Y-axis direction becomes smaller.

[0071] <H. Application Example of Linear Motor 100> Next, referring to FIGS. 15 to 17, an application example of the above-described linear motor 100 will be described. The linear motor 100 can be used, for example, to drive various components within a machine tool.

[0072] The “machine tool” as referred to herein is a concept that encompasses various devices having a function of processing a workpiece. The machine tool 200 may be a horizontal machining center or a vertical machining center. Alternatively, the machine tool 200 may be a lathe, an attachment processing machine, or other cutting or grinding machines.

[0073] When the linear motor 100 is used within a machine tool, the magnet plate 10 that functions as a stator is attached to a stationary component within the machine tool. On the other hand, the slider 50 that functions as a mover is attached to a component to be driven within the machine tool. In this case, a bolt is passed through the component to be driven, and the bolt is fitted into a threaded hole formed in the above-described fixing member 58 formed within the slider 50. Thereby, the component to be driven is fixed to the slider 50.

[0074] (H1. Spindle) First, referring to FIG. 15, an example of applying the linear motor 100 to drive a spindle will be described. FIG. 15 is a diagram showing an example of the device configuration of the machine tool 200.

[0075] The linear motor 100 is used, for example, to move the position of the spindle 250 for rotatably holding a workpiece or tool. The spindle 250 may be a workpiece spindle for rotating a workpiece, or a tool spindle for rotating a tool.

[0076] For the sake of explanation, the coordinate system based on the principal axis 250 will be represented below by the X', Y', and Z' axes. The X', Y', and Z' axes are orthogonal to each other.

[0077] As shown in Figure 15, the machine tool 200 includes a control unit 200A, a drive unit 240A, and a spindle 250.

[0078] The control unit 200A is, for example, a CNC (Computer Numerical Control) device. The CNC device is composed of at least one integrated circuit. The integrated circuit is composed 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.

[0079] The drive unit 240A is a mechanism for driving the spindle 250. The configuration of the drive unit 240A is arbitrary. The drive unit 240A may consist of a single drive unit or multiple drive units. In the example in Figure 15, the drive unit 240A consists of motor drivers 241A to 241C, linear motors 242A to 242C, and encoders 243A to 243C. Each of the linear motors 242A to 242C corresponds to the linear motor 100 described above.

[0080] The motor driver 241A controls the drive of the spindle 250 in the X' axis direction. The motor driver 241A receives a control signal input from the control unit 200A and outputs a current corresponding to the control signal to the linear motor 242A.

[0081] More specifically, the control unit 200A sequentially outputs a control signal, including the target position, to the motor driver 241A. The motor driver 241A calculates the actual position of the spindle 250 from the feedback signal of the encoder 243A and outputs current to the linear motor 242A so as to minimize the difference between the actual position and the target position. As a result, the motor driver 241A moves the spindle 250 to any position in the X' axis direction.

[0082] The motor driver 241B controls the drive of the spindle 250 in the Y' axis direction. The motor driver 241B receives a control signal input from the control unit 200A and outputs a current corresponding to the control signal to the linear motor 242B.

[0083] More specifically, the control unit 200A sequentially outputs a control signal, including the target position, to the motor driver 241B. The motor driver 241B calculates the actual position of the spindle 250 from the feedback signal of the encoder 243B and outputs current to the linear motor 242B so as to minimize the difference between the actual position and the target position. As a result, the motor driver 241B moves the spindle 250 to any position in the Y' axis direction.

[0084] The motor driver 241C controls the drive of the spindle 250 in the Z' axis direction. The motor driver 241C receives a control signal input from the control unit 200A and outputs a current corresponding to the control signal to the linear motor 242C.

[0085] More specifically, the control unit 200A sequentially outputs a control signal, including the target position, to the motor driver 241C. The motor driver 241C calculates the actual position of the spindle 250 from the feedback signal of the encoder 243C and outputs current to the linear motor 242C so as to minimize the difference between the actual position and the target position. As a result, the motor driver 241C moves the spindle 250 to any position in the Z' axis direction.

[0086] (H2. Table) Next, with reference to Figure 16, an example of applying the linear motor 100 to drive a table will be described. Figure 16 shows another example of the device configuration of the machine tool 200.

[0087] The linear motor 100 is used, for example, to drive a table 260 located inside a machine tool. The table 260 is a platform on which a workpiece to be machined is placed.

[0088] As shown in Figure 16, the machine tool 200 includes a control unit 200A, a drive unit 240B, and a table 260.

[0089] The drive unit 240B is a mechanism for driving the table 260. The configuration of the drive unit 240B is arbitrary. The drive unit 240B may consist of a single drive unit or multiple drive units. In the example in Figure 16, the drive unit 240B consists of motor drivers 241D, 241E, linear motors 242D, 242E, and encoders 243D, 243E. Each of the linear motors 242D and 242E corresponds to the linear motor 100 described above.

[0090] The motor driver 241D controls the drive of the table 260 in the X' axis direction. The motor driver 241D receives a control signal input from the control unit 200A and outputs a current corresponding to the control signal to the linear motor 242D.

[0091] More specifically, the control unit 200A sequentially outputs a control signal, including the target position, to the motor driver 241D. The motor driver 241D calculates the actual position of the table 260 from the feedback signal of the encoder 243D and outputs current to the linear motor 242D so as to minimize the difference between the actual position and the target position. As a result, the motor driver 241D moves the table 260 to any position in the X' axis direction.

[0092] The motor driver 241E controls the drive of the table 260 in the Y' axis direction. The motor driver 241E receives a control signal input from the control unit 200A and outputs a current corresponding to the control signal to the linear motor 242E.

[0093] More specifically, the control unit 200A sequentially outputs a control signal, including the target position, to the motor driver 241E. The motor driver 241E calculates the actual position of the table 260 from the feedback signal of the encoder 243E and outputs current to the linear motor 242E so as to minimize the difference between the actual position and the target position. As a result, the motor driver 241E moves the table 260 to any position in the Y' axis direction.

[0094] (H3. Loader) Next, with reference to Figure 17, an example of applying the linear motor 100 to drive a loader will be described. Figure 17 shows another example of the device configuration of the machine tool 200.

[0095] The linear motor 100 is used, for example, to drive a loader 270 for transporting a component. This component may be a workpiece before or after processing, or a tool.

[0096] As shown in Figure 17, the machine tool 200 includes a control unit 200A, a drive unit 240C, and a loader 270.

[0097] The drive unit 240C is a mechanism for driving the loader 270. The configuration of the drive unit 240C is arbitrary. The drive unit 240C may consist of a single drive unit or multiple drive units. In the example in Figure 17, the drive unit 240C consists of motor drivers 241F, 241G, 241H, linear motors 242F, 242G, 242H, and encoders 243F, 243G, 243H. Each of the linear motors 242F, 242G, and 242H corresponds to the linear motor 100 described above.

[0098] The motor driver 241F controls the drive of the loader 270 in the X' axis direction. The motor driver 241F receives a control signal input from the control unit 200A and outputs a current corresponding to the control signal to the linear motor 242F.

[0099] More specifically, the control unit 200A sequentially outputs a control signal, including the target position, to the motor driver 241F. The motor driver 241F calculates the actual position of the loader 270 from the feedback signal of the encoder 243F and outputs current to the linear motor 242F so as to minimize the difference between the actual position and the target position. As a result, the motor driver 241F moves the loader 270 to any position in the X' axis direction.

[0100] The motor driver 241G controls the drive of the loader 270 in the Y' axis direction. The motor driver 241G receives a control signal input from the control unit 200A and outputs a current corresponding to the control signal to the linear motor 242G.

[0101] More specifically, the control unit 200A sequentially outputs a control signal including the target position to the motor driver 241G. The motor driver 241G calculates the actual position of the loader 270 from the feedback signal of the encoder 243G and outputs current to the linear motor 242G so as to minimize the difference between the actual position and the target position. As a result, the motor driver 241G moves the loader 270 to any position in the Y' axis direction.

[0102] The motor driver 241H controls the drive of the loader 270 in the Z' axis direction. The motor driver 241H receives a control signal input from the control unit 200A and outputs a current corresponding to the control signal to the linear motor 242H.

[0103] More specifically, the control unit 200A sequentially outputs a control signal including the target position to the motor driver 241H. The motor driver 241H calculates the actual position of the loader 270 from the feedback signal of the encoder 243H and outputs current to the linear motor 242H so as to minimize the difference between the actual position and the target position. As a result, the motor driver 241H moves the loader 270 to any position in the Z' axis direction.

[0104] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope of equivalents of the claims are intended. [Explanation of Symbols]

[0105] 10 Magnet plate, 12 Magnet, 50 Slider, 51 Slider core, 51A Slider core, 51B Slider core, 51C Slider core, 51X Slider core, 52 Coil, 53 Teeth, 53A Auxiliary teeth, 53B Coil teeth, 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, 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 table, 270 loader.

Claims

1. A linear motor for use in a machine tool, a magnet plate on which a plurality of magnets are arranged in a first direction; a slider including a plurality of coils arranged in the first direction and configured to be slidable in the first direction relative to the magnet plate; a cooling pipe provided on a surface of the slider opposite to a surface facing the magnet plate, The surface portion has grooves and protrusions alternately formed in the first direction, Each of the plurality of grooves extends in a second direction parallel to a surface of the magnetic plate and perpendicular to the first direction, Each of the plurality of protrusions extends in the second direction, The cooling pipe is arranged on the slider so as to meander through the plurality of grooves, When an end portion of each of the plurality of protrusions in the second direction, which is located along a bent portion of the cooling pipe, is defined as a first end portion, on at least one side in the second direction, A linear motor, wherein the entire first end, or a portion of the first end excluding a center portion of the first end in the first direction, is located inside both end surfaces of the slider in the second direction.

2. 2. The linear motor of claim 1, wherein on both sides in the second direction, the entire first end, or a portion of the first end excluding a center portion of the first end in the first direction, is located inside the end faces.

3. 3. A linear motor as described in claim 1 or 2, wherein when the end of the two ends that is not along the bent portion of the cooling pipe is defined as a second end, the second end is located at the same position as either one of the two end faces when viewed from a third direction perpendicular to both the first direction and the second direction.

4. 3. The linear motor according to claim 1, wherein each bent portion of the cooling pipe is positioned outside both end faces when viewed from a third direction perpendicular to both the first direction and the second direction.

5. 3. The linear motor according to claim 1, wherein when viewed from a third direction perpendicular to both the first direction and the second direction, an end of the cooling pipe in the second direction overlaps with an end of the multiple coils in the second direction.

6. The linear motor according to claim 1 , wherein a width of the cooling pipe in the second direction is longer than a width of each of the plurality of coils in the second direction.

7. A linear motor according to claim 1 or 2; a spindle for rotatably holding a workpiece or a tool; The linear motor is used to move the position of the spindle.

8. A linear motor according to claim 1 or 2; A table for placing a workpiece thereon, The linear motor is used to drive the table.

9. A linear motor according to claim 1 or 2; a loader for transporting the member; The linear motor is used to drive the loader.

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