Machine tool

Abstract

To provide a machine tool capable of more accurately positioning a movable body, with respect to a target movement position.SOLUTION: A machine tool comprises: a movable body (30); a linear guide (51) which has a guide rail (61) and a slider (65) attached to the movable body (30) and slidable along the guide rail (61), and which guides the movable body (30) in its movement direction; and a temperature sensor (81) which is provided in the slider (65) and which detects a temperature of the slider (65).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a machine tool. [Background technology]

[0002] For example, Japanese Patent Application Laid-Open Publication No. 2013-234978 (Patent Document 1) discloses a machine tool including a column installed on a bed, a spindle head having a spindle, and a saddle having a table. The spindle head is supported on the front of the column and is movable up and down (Z-axis direction). The saddle is movable horizontally back and forth (Y-axis direction), and a table is disposed on the saddle. The table is movable horizontally left and right (X-axis direction). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-234978 Summary of the Invention [Problem to be solved by the invention]

[0004] There is known a machine tool equipped with a movable body that can move in a linear direction, as disclosed in the above-mentioned Patent Document 1. In such a machine tool, in order to further improve the machining accuracy of a workpiece, it is required to position the movable body with higher accuracy relative to a target movement position specified in an NC program.

[0005] An object of the present invention is to provide a machine tool that is capable of positioning a moving body with higher precision relative to a target movement position. [Means for solving the problem]

[0006] A machine tool according to one aspect of the present invention has a movable body, a guide rail attached to a base, and a slider attached to the movable body and slidable along the guide rail, and is equipped with a linear guide that guides the movable body in its movement direction, and a temperature sensor provided on the slider that detects the temperature of the slider.

[0007] According to another aspect of the present invention, a machine tool has a base, a movable body movable relative to the base, a guide rail attached to the base, and a slider attached to the movable body and slidable along the guide rail, a linear guide that guides the movable body in its direction of movement, and a temperature sensor provided on the slider that detects the temperature of the slider.

[0008] According to yet another aspect of the present invention, there is provided a machine tool comprising: a base body, a movable body having a guide section guided by the base body and movable relative to the base body, a temperature sensor provided on the guide section for detecting the temperature of the guide section, a servo motor serving as a power source for moving the movable body, and a control device for controlling the servo motor based on a position command indicating a target movement position of the movable body, wherein the control device corrects the position command based on the temperature of the guide section detected by the temperature sensor. [Effects of the Invention]

[0009] According to the invention, it is possible to provide a machine tool that is capable of positioning a moving body with higher precision relative to a target movement position. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view showing a machine tool in a first embodiment of the present invention. [Figure 2] 2 is a perspective view showing a guide mechanism and a position detection mechanism in the machine tool in FIG. 1. [Figure 3] FIG. 3 is an exploded view showing a guide mechanism and a position detection mechanism in FIG. 2. [Figure 4] FIG. 3 is a cross-sectional view showing the slider in FIG. 2. [Figure 5] FIG. 2 is a diagram showing the functional configuration of a control system of the machine tool in FIG. [Figure 6] 6 is a table showing a coefficient table in FIG. 5. [Figure 7] 10 is a flowchart showing a flow of control of a servo motor. [Figure 8] 10 is a table showing the change in relative displacement in the X-axis direction over time during the reciprocating movement of the column in the first verification experiment. [Figure 9] 10 is a table showing the change in relative displacement in the Y-axis direction over time during the reciprocating movement of the column in the second verification experiment. [Figure 10] FIG. 10 is a cross-sectional view showing a machine tool according to a second embodiment of the present invention. [Figure 11] FIG. 11 is a perspective view showing a modified example of the attachment position of the temperature sensor in the guide mechanism in FIG. 2 in the machine tool according to the third embodiment of the present invention. [Figure 12] FIG. 10 is a side view showing a machine tool according to a fourth embodiment of the present invention. [Figure 13] FIG. 13 is a diagram showing the functional configuration of a control system of the machine tool in FIG. [Figure 14] 14 is a table showing a coefficient table in FIG. 13. [Figure 15] FIG. 11 is a side view showing a machine tool according to a fifth embodiment of the present invention. [Figure 16] FIG. 16 is a diagram showing the functional configuration of a control system of the machine tool in FIG. [Figure 17] 17 is a table showing a coefficient table in FIG. 16. [Figure 18] FIG. 13 is a side view showing a machine tool according to a sixth embodiment of the present invention. [Figure 19] FIG. 19 is a diagram showing the functional configuration of a control system of the machine tool in FIG. 18. [Figure 20] 20 is a table showing a coefficient table in FIG. 19. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the accompanying drawings, in which the same or equivalent components are designated by the same reference numerals.

[0012] (Embodiment 1) FIG. 1 is a perspective view showing a machine tool according to a first embodiment of the present invention. Referring to FIG. 1, machine tool 100 is a machining center that machines a workpiece by bringing a rotating tool into contact with the workpiece. Machine tool 100 is a horizontal machining center in which the central axis of rotation of the tool extends horizontally. Machine tool 100 is an NC (Numerically Controlled) machine tool in which various operations for machining a workpiece are automated by computer numerical control.

[0013] In this specification, an axis parallel to the horizontal direction and parallel to the central axis of rotation of the tool is referred to as the "Z-axis," an axis parallel to the horizontal direction and perpendicular to the Z-axis is referred to as the "X-axis," and an axis parallel to the vertical direction is referred to as the "Y-axis." When viewing the spindle 21 (described later) from the front, the left direction corresponds to the "+X-axis direction," and the right direction corresponds to the "-X-axis direction." When viewing the spindle 21 (described later) from the front, the front direction corresponds to the "+Z-axis direction," and the back direction corresponds to the "-Z-axis direction." The up direction corresponds to the "+Y-axis direction," and the down direction corresponds to the "-Y-axis direction."

[0014] The machine tool to which the present invention is applied is not limited to a horizontal machining center, but may be, for example, a vertical machining center, a lathe that processes a workpiece by bringing a tool into contact with a rotating workpiece, or a multi-tasking machine that has a turning function using a fixed tool and a milling function using a rotating tool.The machine tool to which the present invention is applied may also be an AM / SM hybrid machine that is capable of both additive manufacturing and subtractive manufacturing of a workpiece.

[0015] The machine tool 100 has a bed 12 , a column 31 , a spindle head 22 , and a table 41 .

[0016] The bed 12 is a base member for supporting the column 31, the spindle head 22, the table 41, etc., and is fixed to the floor of a factory, etc. The bed 12 is made of metal such as cast iron.

[0017] The column 31 is supported by the bed 12. The column 31 has an overall gate-like shape that rises upward from the bed 12. The column 31 is disposed at the end of the bed 12 in the -Z-axis direction. The column 31 can be moved in the X-axis direction by various feed mechanisms, guide mechanisms, servo motors, etc.

[0018] The spindle head 22 is supported by a column 31. The spindle head 22 has an overall cylindrical shape that protrudes in the +Z-axis direction from the column 31. The spindle head 22 is movable in the Y-axis direction by various feed mechanisms, guide mechanisms, servo motors, etc.

[0019] The spindle head 22 has a spindle (tool spindle) 21. The spindle 21 can be rotated by a motor around a rotation center axis 101 that is parallel to the Z axis. A clamping mechanism for holding a tool for machining a workpiece in the machine tool 100 is built into the spindle 21. As the spindle 21 rotates, the tool held by the spindle 21 rotates around the rotation center axis 101.

[0020] The table 41 is supported by the bed 12. The table 41 is provided on the bed 12. The table 41 is provided at a position away from the column 31 in the +Z-axis direction. The table 41 is a device for holding a workpiece. The table 41 holds the workpiece at a position facing the spindle 21 in the Z-axis direction. The table 41 can be moved in the Z-axis direction by various feed mechanisms, guide mechanisms, servo motors, etc. The table 41 has a built-in rotation mechanism for rotating a pallet mounted on the table 41 around a rotation center axis extending in the Y-axis direction (up and down direction).

[0021] In this configuration, the machining position of the workpiece by the tool moves three-dimensionally by a combination of movement of the column 31 in the X-axis direction, movement of the spindle head 22 (spindle 21) in the Y-axis direction, and movement of the table 41 in the Z-axis direction.

[0022] The column 31, the spindle head 22, and the table 41 each correspond to a movable moving body 30. The column 31 as the moving body 30 is movable relative to the bed 12 as the base body 10. The spindle head 22 as the moving body 30 is movable relative to the column 31 as the base body 10. The table 41 as the moving body 30 is movable relative to the bed 12 as the base body 10.

[0023] Fig. 2 is a perspective view showing a guide mechanism and a position detection mechanism in the machine tool in Fig. 1. Fig. 3 is an exploded assembly view showing the guide mechanism and the position detection mechanism in Fig. 2.

[0024] 1 to 3, machine tool 100 further includes linear guides 51 (51A, 51B) and a linear scale 71. Linear guide 51 constitutes a guide mechanism that guides movable body 30 in its movement direction. Linear scale 71 constitutes a position detection mechanism that detects the position of movable body 30.

[0025] The linear guide 51 and the linear scale 71 are provided for each of the moving bodies 30, namely, the column 31, the spindle head 22 (spindle 21), and the table 41.

[0026] Linear guides 51 provided for column 31 guide column 31 in the X-axis direction. Machine tool 100 has linear guides 51A and 51B as linear guides 51 that guide column 31 in the X-axis direction. Linear guides 51A and 51B are provided spaced apart from each other in the Z-axis direction, which is perpendicular to the X-axis direction, which is the movement direction of column 31. Linear scale 71 provided for column 31 detects the position of column 31 in the X-axis direction.

[0027] Linear guide 51 provided for spindle head 22 guides spindle head 22 in the Y-axis direction. Machine tool 100 has linear guide 51A and linear guide 51B as linear guides 51 that guide spindle head 22 in the Y-axis direction. Linear guide 51A and linear guide 51B are provided spaced apart from each other in the X-axis direction, which is perpendicular to the Y-axis direction, which is the movement direction of spindle head 22. Linear scale 71 provided for spindle head 22 detects the position of spindle head 22 in the Y-axis direction.

[0028] Linear guides 51 provided for table 41 guide table 41 in the Z-axis direction. Machine tool 100 has linear guides 51A and 51B as linear guides 51 that guide table 41 in the Z-axis direction. Linear guides 51A and 51B are provided at an interval from each other in the X-axis direction, which is perpendicular to the Z-axis direction, which is the movement direction of table 41. Linear scale 71 provided for table 41 detects the position of table 41 in the Z-axis direction.

[0029] The linear guides 51 and linear scales 71 provided for each movable body 30 of the column 31, the spindle head 22, and the table 41 basically have the same structure. Below, we will explain, as a representative example, the structure of the linear guide 51 that guides the column 31 in the X-axis direction and the structure of the linear scale 71 that detects the position of the column 31 in the X-axis direction, as shown in Figures 2 and 3.

[0030] As shown in FIGS. 2 and 3, the linear guide 51 includes a guide rail 61 and sliders 65 (65J, 65K).

[0031] The guide rail 61 extends in the X-axis direction. The guide rail 61 is attached to the bed 12. The guide rail 61 is fastened to the bed 12 using bolts or the like. The guide rail 61 is made of metal. When the guide rail 61 is cut along the Y-axis-Z-axis plane, it has a cross section that is constricted in the Z-axis direction at the center in the Y-axis direction.

[0032] The slider 65 is attached to the column 31. The slider 65 is fastened to the column 31 using bolts or the like. The slider 65 is slidable in the X-axis direction along the guide rail 61. When the slider 65 is cut along the Y-axis-Z-axis plane, it opens toward the -Y-axis direction and has a concave cross section that can receive the guide rail 61.

[0033] The slider 65J and the slider 65K are spaced apart from each other in the X-axis direction, which is the direction in which the column 31 moves.

[0034] The slider 65 has a main body portion 66 and resin portions 67 (67p, 67q). The main body portion 66 is made of metal. The main body portion 66 engages with the guide rail 61 via a plurality of rolling elements (not shown), such as balls or rollers. The main body portion 66 is fastened to the column 31. The resin portion 67 is made of resin, such as polyacetal resin (POM resin). The resin portion 67 is adjacent to the main body portion 66 in the X-axis direction, which is the movement direction of the column 31. The resin portion 67 is connected to the main body portion 66. The length of the resin portion 67 in the X-axis direction is shorter than the length of the main body portion 66 in the X-axis direction.

[0035] Resin portion 67p is connected to the side surface of main body portion 66 facing the +X-axis direction. Resin portion 67q is connected to the side surface of main body portion 66 facing the -X-axis direction. Resin portion 67q of slider 65J and resin portion 67p of slider 65K face each other in the X-axis direction.

[0036] The linear scale 71 has a scale section 72 and a head section 76. A scale (not shown) is recorded on the scale section 72. The scale section 72 is provided on the guide rail 61. The scale section 72 is not limited to being provided on the guide rail 61, and may be provided on the bed 12 near the guide rail 61. The head section 76 moves in the X-axis direction together with the column 31. The head section 76 is capable of reading the scale recorded on the scale section 72.

[0037] The scale unit 72 has a base unit 73, a scale main body 74, and a cover 75. The base unit 73 extends in the X-axis direction. The base unit 73 is attached to the top surface of the guide rail 61. The scale main body 74 is made of an elongated magnetic body with its longitudinal direction in the X-axis direction, and has a scale recorded thereon magnetically. The scale is marked at equal intervals in the X-axis direction. The scale main body 74 is supported by the base unit 73. The cover 75 is attached to the base unit 73 so as to cover the scale main body 74. The cover 75 is made of, for example, stainless steel foil.

[0038] The head portion 76 is attached to the column 31. The head portion 76 is fastened to the column 31 using bolts or the like. The slider 65J, the head portion 76, and the slider 65K are aligned at intervals in the X-axis direction. The head portion 76 is provided between the slider 65J and the slider 65K in the X-axis direction. The distance between the head portion 76 and the slider 65J in the X-axis direction may be the same as or different from the distance between the head portion 76 and the slider 65K in the X-axis direction. The head portion 76 is provided with a TMR (tunnel magnetoresistance) sensor (not shown) for reading the scale recorded on the scale portion 72. The head portion 76 is not in contact with the linear guide 51. The TMR sensor is provided on the bottom surface of the head portion 76 so as to face the scale portion 72 with a gap in the Y-axis direction.

[0039] When the column 31 moves in the X-axis direction, the head unit 76 moves in the X-axis direction while maintaining a fixed distance from the sliders 65J and 65K. The head unit 76 moves in the X-axis direction while facing the scale unit 72 with a fixed gap between them. The TMR sensor provided in the head unit 76 moves in the X-axis direction while facing the scale main body 74 via the cover 75, and reads the scale marks recorded on the scale main body 74.

[0040] Fig. 4 is a cross-sectional view showing the slider in Fig. 2. With reference to Figs. 2 to 4, machine tool 100 further has a temperature sensor 81. Temperature sensor 81 is formed of, for example, a thermistor.

[0041] The temperature sensor 81 is provided on the slider 65. The temperature sensor 81 is capable of detecting the temperature of the slider 65. The temperature sensor 81 is provided on the slider 65J. The temperature sensor 81 is capable of detecting the temperature of the slider 65J. The temperature sensor 81 is not provided on the slider 65K.

[0042] As shown in FIG. 4, the temperature sensor 81 is supported by the resin portion 67 so as to be in contact with the main body portion 66. The temperature sensor 81 is supported by the resin portion 67q of the slider 65J. A hole 68 is provided in the resin portion 67. The hole 68 penetrates the resin portion 67 in the X-axis direction. The temperature sensor 81 is disposed in the hole 68. The tip of the temperature sensor 81 in the X-axis direction abuts against the main body portion 66. Note that the hole 68 is originally provided as a supply path for lubricating oil to the rolling elements. In the slider 65J in which the resin portion 67q is used to support the temperature sensor 81, lubricant is supplied to the rolling elements through a hole provided in the resin portion 67p.

[0043] When viewed in the X-axis direction, which is the sliding direction of the slider 65, the temperature sensor 81 may be provided so as to be able to detect the temperature of the center of the slider 65 in the Z-axis direction. The tip of the temperature sensor 81 in the X-axis direction may abut against the center of the main body 66 in the Z-axis direction. The temperature sensor 81 is provided at a position where frictional heat is generated as the column 31 moves in the X-axis direction, while the TMR sensor is provided at a position where such frictional heat is not generated.

[0044] The linear scale 71 is provided on the linear guide 51A. The linear scale 71 is not provided on the linear guide 51B. The temperature sensor 81 is provided on the slider 65 of the linear guide 51A. The temperature sensor 81 is not provided on the slider 65 of the linear guide 51B.

[0045] The linear scale 71 may be provided on both the linear guide 51A and the linear guide 51B. The temperature sensor 81 may be provided on both the slider 65 of the linear guide 51A and the slider 65 of the linear guide 51B. The temperature sensor 81 may be provided on both the slider 65J and the slider 65K of each linear guide 51.

[0046] Fig. 5 is a diagram showing the functional configuration of a control system of the machine tool in Fig. 1. With reference to Figs. 1 and 5, machine tool 100 further has servo motors 141 (141X, 141Y, 141Z) which are power sources for moving movable body 30. Servo motor 141X is a power source for moving column 31 in the X-axis direction, servo motor 141Y is a power source for moving spindle head 22 in the Y-axis direction, and servo motor 141Z is a power source for moving table 41 in the Z-axis direction.

[0047] To explain the structure of the servo motor 141X as a representative example, the servo motor 141X is attached to the bed 12. The screw of the ball screw, which is the feed mechanism, is connected to the output shaft of the servo motor 141, and the nut of the ball screw is connected to the column 31. The rotational motion output from the servo motor 141X is converted into linear motion in the X-axis direction by the ball screw and transmitted to the column 31.

[0048] 5, the machine tool 100 further includes a control device 120. The control device 120 controls the operation of the machine tool 100.

[0049] The components of the control device 120 are realized by hardware including computing units such as a CPU (Central Processing Unit) and various computer processors, storage devices such as memory or storage, and wired or wireless communication lines connecting them, as well as software stored in the storage devices and supplying processing instructions to the computing units. The computer programs may be configured by device drivers, an operating system, various application programs located at higher layers than these, or libraries that provide common functions to these programs.

[0050] The control device 120 includes a program analysis unit 131 , a position command unit 132 , a motor control unit 133 , and a position command correction unit 161 .

[0051] The program analysis unit 131 reads out an NC program (machining program) stored in the storage unit 156 (described later). The program analysis unit 131 analyzes the NC program. The program analysis unit 131 extracts information relating to a target movement position and movement speed of the moving body 30 included in the NC program, and outputs the extracted information relating to the target movement position and movement speed to the position command unit 132.

[0052] The position command unit 132 sequentially generates position commands Px, Py, Pz for the X-axis, Y-axis, and Z-axis according to the movement speed based on the input information relating to the target movement position and movement speed of the moving body 30, and outputs the generated position commands Px, Py, Pz to the position command correction unit 161 and the motor control unit 133.

[0053] The motor control unit 133 controls the servo motor 141. The motor control unit 133 generates a control signal (current control signal) according to a position command from the position command unit 132, and controls the servo motor 141 using the generated control signal. More specifically, the motor control unit 133 generates a control signal according to a position command Px from the position command unit 132, and controls the servo motor 141X using the generated control signal. The motor control unit 133 generates a control signal according to a position command Py from the position command unit 132, and controls the servo motor 141Y using the generated control signal. The motor control unit 133 generates a control signal according to a position command Pz from the position command unit 132, and controls the servo motor 141Z using the generated control signal.

[0054] Position command corrector 161 corrects position commands Px, Py, Pz from position command unit 132 when thermal displacement occurs in machine tool 100. When position command corrector 161 corrects position commands Px, Py, Pz, the corrected position commands px, py, pz are input to motor control unit 133. Motor control unit 133 generates control signals in accordance with the corrected position commands, and controls servo motor 141 using the generated control signals.

[0055] The motor control unit 133 further executes feedback control of the servo motor 141 based on position data of the movable body 30 detected by the linear scale 71. More specifically, the motor control unit 133 executes feedback control of the servo motor 141X based on position data of the X axis of the column 31 detected by the linear scale 71. The motor control unit 133 executes feedback control of the servo motor 141Y based on position data of the Y axis of the spindle head 22 detected by the linear scale 71. The motor control unit 133 executes feedback control of the servo motor 141Z based on position data of the Z axis of the table 41 detected by the linear scale 71.

[0056] Machine tool 100 has linear guides 51 including linear guide 51X, linear guide 51Y, and linear guide 51Z.

[0057] The linear guide 51X guides the column 31 in the X-axis direction and corresponds to the linear guide 51 shown in Figures 2 and 3. The linear guide 51Y guides the spindle head 22 in the Y-axis direction. The guide rail 61 of the linear guide 51Y is attached to the column 31. The slider 65 of the linear guide 51Y is attached to the spindle head 22. The linear guide 51Z guides the table 41 in the Z-axis direction. The guide rail 61 of the linear guide 51Z is attached to the bed 12. The slider 65 of the linear guide 51Z is attached to the table 41.

[0058] Machine tool 100 has, as temperature sensors 81, temperature sensor 81X, temperature sensor 81Y, and temperature sensor 81Z.

[0059] The temperature sensor 81X is provided on the slider 65 of the linear guide 51X and corresponds to the temperature sensor 81 shown in FIGS. 2 to 4. The temperature sensor 81X detects the temperature Tx of the slider 65 of the linear guide 51X (hereinafter also referred to as the "X-axis slider temperature Tx"). The temperature sensor 81Y is provided on the slider 65 of the linear guide 51Y. The temperature sensor 81Y detects the temperature Ty of the slider 65 of the linear guide 51Y (hereinafter also referred to as the "Y-axis slider temperature Ty"). The temperature sensor 81Z is provided on the slider 65 of the linear guide 51Z. The temperature sensor 81Z detects the temperature Tz of the slider 65 of the linear guide 51Z (hereinafter also referred to as the "Z-axis slider temperature Tz").

[0060] Machine tool 100 further has temperature sensor 82. Temperature sensor 82 is formed, for example, by a thermistor. Temperature sensor 82 is provided at a position away from temperature sensors 81 (81X, 81Y, 81Z). Temperature sensor 82 is provided on bed 12. Temperature sensor 82 is provided near the floor of a factory or the like to which bed 12 is fixed. Temperature sensor 82 detects machine tool 100's body temperature t. Machine tool temperature t is a reference temperature that depends on the ambient temperature (air temperature) of machine tool 100.

[0061] Temperature sensors 81 (81X, 81Y, 81Z) generate signals of the detected temperatures of slider 65 (X-axis slider temperature Tx, Y-axis slider temperature Ty, Z-axis slider temperature Tz) and output the signals to control device 120. Temperature sensor 82 generates a signal of the detected body temperature t of machine tool 100 and outputs the signal to control device 120.

[0062] Control device 120 further has a temperature data acquisition unit 151. Temperature data acquisition unit 151 acquires temperature data including the temperatures of slider 65 detected by temperature sensor 81 (X-axis slider temperature Tx, Y-axis slider temperature Ty, Z-axis slider temperature Tz) and machine body temperature t of machine tool 100 detected by temperature sensor 82.

[0063] The temperature data acquisition unit 151 identifies the X-axis slider temperature Tx based on a signal from the temperature sensor 81X. The temperature data acquisition unit 151 identifies the Y-axis slider temperature Ty based on a signal from the temperature sensor 81Y. The temperature data acquisition unit 151 identifies the Z-axis slider temperature Tz based on a signal from the temperature sensor 81Z. The temperature data acquisition unit 151 identifies the machine body temperature t of the machine tool 100 based on a signal from the temperature sensor 82. The temperature data acquisition unit 151 outputs the acquired temperature data to the position command correction unit 161.

[0064] Fig. 6 is a table showing the coefficient table in Fig. 5. With reference to Fig. 5 and Fig. 6, control device 120 further includes a storage unit 156. Storage unit 156 stores a coefficient table 157.

[0065] The position command corrector 161 corrects the position commands Px, Py, and Pz based on the temperature of the slider 65 detected by the temperature sensor 81.

[0066] More specifically, position command corrector 161 has thermal change amount calculator 162X, thermal change amount calculator 162Y, and thermal change amount calculator 162Z. Thermal change amount calculator 162X calculates the amount of thermal change Dx in the X-axis direction of machine tool 100. Thermal change amount calculator 162Y calculates the amount of thermal change Dy in the Y-axis direction of machine tool 100. Thermal change amount calculator 162Z calculates the amount of thermal change Dz in the Z-axis direction of machine tool 100.

[0067] The calculation of the thermal change amount Dx by the thermal change amount calculation unit 162X, the calculation of the thermal change amount Dy by the thermal change amount calculation unit 162Y, and the calculation of the thermal change amount Dz by the thermal change amount calculation unit 162Z are performed in the same manner. As a representative example, the calculation of the thermal change amount Dx by the thermal change amount calculation unit 162X will be described.

[0068] The thermal change amount calculation unit 162X reads out the coefficient table 157 from the storage unit 156. The thermal change amount calculation unit 162X refers to the coefficient table 157 to identify the coefficient Cxx to be applied to the X-axis position correction using the X-axis slider temperature Tx. The thermal change amount calculation unit 162X calculates the thermal change amount dxx in the X-axis direction due to heat generation from the slider 65 of the linear guide 51X by substituting the X-axis slider temperature Tx, the machine body temperature t, and the coefficient Cxx into the formula (Tx - t) × Cxx. The thermal change amount dxx is mainly caused by heat generated by the slider 65 of the linear guide 51X as the column 31 moves in the X-axis direction, and the heat being transmitted via the guide rail 61 of the linear guide 51X to the bed 12 or the scale unit 72 of the linear scale 71 that detects the X-axis position of the column 31.

[0069] The thermal displacement calculation unit 162X refers to the coefficient table 157 to identify the coefficient Cyx to be applied to the X-axis position correction using the Y-axis slider temperature Ty. The thermal displacement calculation unit 162X calculates the thermal displacement dyx in the X-axis direction due to heat generation of the slider 65 of the linear guide 51Y by substituting the Y-axis slider temperature Ty, the machine body temperature t, and the coefficient Cyx into the formula (Ty-t)×Cyx. The thermal displacement dyx is mainly caused by the slider 65 of the linear guide 51Y generating heat as the spindle head 22 moves in the Y-axis direction, and the heat being transmitted via the column 31 and the linear guide 51X to the bed 12 or the scale portion 72 of the linear scale 71 that detects the X-axis position of the column 31.

[0070] The thermal displacement calculation unit 162X refers to the coefficient table 157 to identify the coefficient Czx to be applied to the X-axis position correction using the Z-axis slider temperature Tz. The thermal displacement calculation unit 162X calculates the thermal displacement dzx in the X-axis direction due to heat generation from the slider 65 of the linear guide 51Z by substituting the Z-axis slider temperature Tz, the machine body temperature t, and the coefficient Czx into the formula (Tz-t) × Czx. The thermal displacement dzx is mainly caused by the heat generated by the slider 65 of the linear guide 51Z as the table 41 moves in the Z-axis direction, and the heat being transmitted via the guide rail 61 of the linear guide 51Z to the scale portion 72 of the linear scale 71 that detects the X-axis position of the bed 12 or the column 31.

[0071] The thermal change amount calculation unit 162X calculates the thermal change amount Dx, which is the sum of the thermal change amounts dxx, dyx, and dzx (Dx=dxx+dyx+dzx).

[0072] Using a similar method, the thermal displacement calculation unit 162Y uses the coefficient Cxy to calculate the thermal displacement dxy in the Y-axis direction due to heat generation of the slider 65 of the linear guide 51X, uses the coefficient Cyy to calculate the thermal displacement dyy in the Y-axis direction due to heat generation of the slider 65 of the linear guide 51Y, and uses the coefficient Czy to calculate the thermal displacement dzy in the Y-axis direction due to heat generation of the slider 65 of the linear guide 51Z. The thermal displacement calculation unit 162Y calculates the thermal displacement Dy, which is the sum of the thermal displacement dxy, the thermal displacement dyy, and the thermal displacement dzy (Dy=dxy+dyy+dzy).

[0073] Furthermore, the thermal displacement calculation unit 162Z uses the coefficient Cxz to calculate the thermal displacement dxz in the Z-axis direction due to heat generation of the slider 65 of the linear guide 51X, uses the coefficient Cyz to calculate the thermal displacement dyz in the Z-axis direction due to heat generation of the slider 65 of the linear guide 51Y, and uses the coefficient Czz to calculate the thermal displacement dzz in the Z-axis direction due to heat generation of the slider 65 of the linear guide 51Z. The thermal displacement calculation unit 162Z calculates the thermal displacement Dz, which is the sum of the thermal displacement dxz, the thermal displacement dyz, and the thermal displacement dzz (Dz=dxz+dyz+dzz).

[0074] The coefficient C shown in Figure 6 was determined in advance through an experiment conducted by an operator at the manufacturer of the machine tool 100. In the experiment, each moving body 30 (column 31, spindle head 22, table 41) was continuously reciprocated, causing the slider 65, which guides these moving bodies 30 in the axial direction, to generate heat. As the slider 65 generated heat, a temperature sensor was used to measure the temperature of the slider 65 and the temperature of the base body of the machine tool 100, and further, a measuring instrument such as a digital gauge was used to measure the amount of thermal displacement in the X-axis, Y-axis, and Z-axis directions at each temperature. The coefficient C was determined from the relationship between the measured temperature value and the measured amount of thermal displacement.

[0075] 6, during X-axis position correction, the slider 65 of the linear guide 51X corresponds to the axial slider, and the sliders 65 of the linear guides 51Y and 51Z correspond to the axis-orthogonal sliders. During Y-axis position correction, the slider 65 of the linear guide 51Y corresponds to the axial slider, and the sliders 65 of the linear guides 51X and 51Z correspond to the axis-orthogonal sliders. During Z-axis position correction, the slider 65 of the linear guide 51Z corresponds to the axial slider, and the sliders 65 of the linear guides 51X and 51Y correspond to the axis-orthogonal sliders.

[0076] 1 and 6, the coefficient C applied to position correction using the axial slider temperature increases as the distance from the reference position in the axial direction increases, while the coefficient C applied to position correction using the orthogonal-axis slider temperature remains constant. In Fig. 6, for machine tool 100 having machine specifications of an X-axis stroke of 800 mm, a Y-axis stroke of 800 mm, and a Z-axis stroke of 880 mm, the coefficient C applied to position correction based on the axial slider temperature is simply determined for each predetermined range in the axial direction.

[0077] For example, as the coefficient Cxx applied to the X-axis position correction using the X-axis slider temperature Tx, Cxx1 is set when the X-axis coordinate is in the range of 0 to -200 mm, Cxx2 larger than Cxx1 is set when the X-axis coordinate is in the range of -200 to -400 mm, Cxx3 larger than Cxx2 is set when the X-axis coordinate is in the range of -400 to -600 mm, and Cxx4 larger than Cxx3 is set when the X-axis coordinate is in the range of -600 to -800 mm. Thermal displacement amount calculation unit 162X identifies the coefficient Cxx in the range including the value of position command Px by comparing the value of position command Px with coefficient table 157.

[0078] The coefficient C applied to the position correction based on the slider temperature in the direction perpendicular to the axis may also be determined for each predetermined range in each axial direction, similar to the coefficient C applied to the position correction based on the slider temperature in the axial direction.

[0079] The position command corrector 161 further includes a correction executor 163. The correction executor 163 corrects the position command Px based on the thermal change amount Dx calculated by the thermal change amount calculator 162X. The correction executor 163 corrects the position command Py based on the thermal change amount Dy calculated by the thermal change amount calculator 162Y. The correction executor 163 corrects the position command Pz based on the thermal change amount Dz calculated by the thermal change amount calculator 162Z.

[0080] More specifically, the correction execution unit 163 calculates a corrected position command px by subtracting the thermal change amount Dx from the position command Px (px = Px - Dx). The correction execution unit 163 calculates a corrected position command py by subtracting the thermal change amount Dy from the position command Py (py = Py - Dy). The correction execution unit 163 calculates a corrected position command pz by subtracting the thermal change amount Dz from the position command Pz (pz = Pz - Dz). The correction execution unit 163 outputs the calculated corrected position commands px, py, and pz to the servo motors 141 (141X, 141Y, 141Z).

[0081] Fig. 7 is a flowchart showing the flow of servo motor control. With reference to Fig. 5 to Fig. 7, as machine tool 100 operates in accordance with the NC program, temperature sensor 81X, temperature sensor 81Y, and temperature sensor 81Z detect X-axis slider temperature Tx, Y-axis slider temperature Ty, and Z-axis slider temperature Tz, respectively, and temperature sensor 82 detects machine body temperature t of machine tool 100 (S110).

[0082] Next, the control device 120 (temperature data acquisition unit 151) acquires temperature data including the X-axis slider temperature Tx, the Y-axis slider temperature Ty, the Z-axis slider temperature Tz, and the device temperature t detected in step S110 (S120).

[0083] Next, the control device 120 (thermal change amount calculation unit 162X) refers to the coefficient table 157 recorded in the storage unit 156 to identify the coefficients Cxx, Cyx, and Czx. The control device 120 (thermal change amount calculation unit 162Y) refers to the coefficient table 157 recorded in the storage unit 156 to identify the coefficients Cxy, Cyy, and Czy. The control device 120 (thermal change amount calculation unit 162Z) refers to the coefficient table 157 recorded in the storage unit 156 to identify the coefficients Cxz, Cyz, and Czz (S130).

[0084] Next, the control device 120 (thermal change amount calculation unit 162X) calculates the thermal change amount dxx using the coefficient Cxx identified in step S130 and the X-axis slider temperature Tx and body temperature t obtained in step S120, calculates the thermal change amount dyx using the coefficient Cyx identified in step S130 and the Y-axis slider temperature Ty and body temperature t obtained in step S120, and calculates the thermal change amount dzx using the coefficient Cxz identified in step S130 and the Z-axis slider temperature Tz and body temperature t obtained in step S120.

[0085] Similarly, the control device 120 (thermal change amount calculation unit 162Y) calculates the thermal change amounts dxy, dyy, and dzy. The control device 120 (thermal change amount calculation unit 162Z) calculates the thermal change amounts dxz, dyz, and dzz (S140).

[0086] Next, the control device 120 (thermal change amount calculation unit 162X) calculates the thermal change amount Dx in the X-axis direction using the thermal change amounts dxx, dyx, and dzx calculated in step S140. Similarly, the control device 120 (thermal change amount calculation unit 162Y) calculates the thermal change amount Dy in the Y-axis direction. The control device 120 (thermal change amount calculation unit 162Z) calculates the thermal change amount Dz in the Z-axis direction (S150).

[0087] Next, the control device 120 (correction execution unit 163) corrects the position command Px from the position command unit 132 to a position command px using the thermal change amount Dx calculated in step S150. The control device 120 (correction execution unit 163) corrects the position command Py from the position command unit 132 to a position command py using the thermal change amount Dy calculated in step S150. The control device 120 (correction execution unit 163) corrects the position command Pz from the position command unit 132 to a position command pz using the thermal change amount Dz calculated in step S150 (S160).

[0088] Next, the control device 120 (motor control unit 133) controls the servo motors 141 (141X, 141Y, 141Z) in accordance with the corrected position commands px, py, pz (S170).

[0089] The control device 120 repeatedly executes the steps described above every time a new target movement position of the moving body 30 is specified in the ongoing NC program.

[0090] Figure 8 is a table showing the change in relative displacement in the X-axis direction over time during the reciprocating movement of the column in the first verification experiment. Figure 9 is a table showing the change in relative displacement in the Y-axis direction over time during the reciprocating movement of the column in the second verification experiment.

[0091] 1, 8, and 9, a machine tool 100 with machine specifications of an X-axis stroke of 800 mm, a Y-axis stroke of 800 mm, and a Z-axis stroke of 880 mm was used in both the first and second verification experiments. Column 31 was continuously reciprocated within the ranges of X-axis coordinates 0 to -200 mm, 0 to -400 mm, and 0 to -600 mm (feed rate F = 30,000 mm / min, movement time 8 hours). The axial slider temperature (slider 65 of linear guide 51X) at the end of the reciprocating movement had risen by 1.9°C from the start of the reciprocating movement.

[0092] 8, the relative displacement in the X-axis direction between the cutting edge of the tool attached to spindle 21 and table 41 was measured at each of the positions of X-axis coordinate -200 mm, X-axis coordinate -400 mm, and X-axis coordinate -600 mm, and the change in relative displacement over time is shown in the figure. In the example with correction, the X-axis position command was corrected using the axial slider temperature (the temperature of slider 65 of linear guide 51X), and in the comparative example without correction, the X-axis position command was not corrected.

[0093] 9, the relative displacement in the Y-axis direction between the cutting edge of the tool attached to spindle 21 and table 41 was measured at each of the positions of X-axis coordinate -200 mm, X-axis coordinate -400 mm, and X-axis coordinate -600 mm, and the change in relative displacement over time is shown in the figure. In the example with correction, the Y-axis position command was corrected using the slider temperature in the direction perpendicular to the axis (the temperature of slider 65 of linear guide 51X), and in the comparative example without correction, the Y-axis position command was not corrected.

[0094] In both the first and second verification experiments, by correcting the position command, it was possible to suppress the occurrence of relative displacement between the cutting edge of the tool attached to the spindle 21 and the table 41.

[0095] To summarize the structure of machine tool 100 in embodiment 1 of the present invention as described above, machine tool 100 in this embodiment has a base 10, a movable body 30 movable relative to base 10, a guide rail 61 attached to base 10, a slider 65 attached to movable body 30 and slidable along guide rail 61, a linear guide 51 that guides movable body 30 in its movement direction, and a temperature sensor 81 provided on slider 65 that detects the temperature of slider 65.

[0096] In addition, machine tool 100 in this embodiment has a movable body 30, a guide rail 61 attached to base 10, a slider 65 attached to movable body 30 and slidable along guide rail 61, a linear guide 51 that guides movable body 30 in its movement direction, and a temperature sensor 81 provided on slider 65 that detects the temperature of slider 65.

[0097] With this configuration, the temperature of the slider 65 detected by the temperature sensor 81 can be used to identify the amount of thermal displacement caused by heat generated by the slider 65, which is the heat source. This makes it possible to remove the influence of thermal displacement caused by heat generated by the slider 65 from the position command indicating the target movement position of the movable body 30, thereby enabling the movable body 30 to be positioned with higher accuracy relative to the target movement position.

[0098] Machine tool 100 also includes servo motor 141, which serves as a power source for moving movable body 30, and control device 120, which controls servo motor 141 based on a position command indicating a target movement position of movable body 30. Control device 120 corrects the position command based on the temperature of slider 65 detected by temperature sensor 81.

[0099] According to this configuration, the effect of thermal displacement due to heat generation of the slider 65 can be removed from the position command indicating the target movement position of the movable body 30 by performing correction by the control device 120. This allows the movable body 30 to be positioned with higher accuracy relative to the target movement position.

[0100] In addition, the control device 120 corrects the position command Px indicating the target movement position of the column 31, corrects the position command Py indicating the target movement position of the spindle head 22, and corrects the position command Pz indicating the target movement position of the table 41 based on the temperature of the slider 65 of the linear guide 51X detected by the temperature sensor 81X, the temperature of the slider 65 of the linear guide 51Y detected by the temperature sensor 81Y, and the temperature of the slider 65 of the linear guide 51Z detected by the temperature sensor 81Z.

[0101] With this configuration, it is possible to eliminate not only the influence of heat generated by the axial slider but also the influence of heat generated by the orthogonal-to-axial slider from the position command indicating the target movement position of each of the movable bodies 30, i.e., the column 31, the spindle head 22, and the table 41. This allows the movable body 30 to be positioned with even higher accuracy relative to its target movement position.

[0102] Furthermore, the temperature sensor 81 is supported by the resin part 67 of the slider 65 so as to be in contact with the main body part 66 of the slider 65. With this configuration, the temperature sensor 81 can be supported by a simple configuration, and the temperature of the slider 65 can be detected more accurately by the temperature sensor 81.

[0103] Machine tool 100 in this embodiment also includes base 10, movable body 30 having slider 65 as a guide portion guided by base 10 and movable relative to base 10, temperature sensor 81 provided on slider 65 for detecting the temperature of slider 65, servo motor 141 serving as a power source for moving movable body 30, and control device 120 for controlling servo motor 141 based on a position command indicating a target movement position of movable body 30. Control device 120 corrects the position command based on the temperature of slider 65 detected by temperature sensor 81.

[0104] According to this configuration, the effect of thermal displacement due to heat generation of the slider 65 can be removed from the position command indicating the target movement position of the movable body 30 by performing correction by the control device 120. This allows the movable body 30 to be positioned with higher accuracy relative to the target movement position.

[0105] The machine tool in this embodiment includes a movable body, a guide rail, a linear guide having a slider attached to the movable body and slidable along the guide rail, which guides the movable body in its moving direction, and a temperature sensor provided on the slider to detect the temperature of the slider. The temperature sensor is located within the plane of the slider when viewed in the sliding direction of the slider.

[0106] With this configuration, the temperature of the slider detected by the temperature sensor can be used to determine the amount of thermal displacement caused by heat generated by the slider, which is the heat source. This makes it possible to eliminate the influence of thermal displacement caused by heat generated by the slider from the position command indicating the target movement position of the movable body, thereby enabling the movable body to be positioned with higher accuracy relative to the target movement position. Furthermore, the temperature sensor is located within the plane of the slider when viewed in the sliding direction of the slider. With this configuration, the temperature sensor is provided in the space through which the slider moves as it slides, making it possible to easily ensure installation space for the temperature sensor relative to the slider while avoiding interference between the temperature sensor and components around the linear guide.

[0107] (Embodiment 2) 10 is a cross-sectional view showing a machine tool according to a second embodiment of the present invention. Machine tool 200 according to the present embodiment basically has the same structure as machine tool 100 according to the first embodiment. Hereinafter, description of the overlapping structure will not be repeated.

[0108] 10, machine tool 200 in this embodiment employs a slideway guide system for guiding movable body 30 relative to base body 10. Fig. 10 representatively shows cross sections of bed 12 as base body 10 and column 31 as movable body 30.

[0109] The bed 12 has a sliding portion 16. The column 31 has a sliding portion 32. The sliding portion 16 and the sliding portion 32 face each other in the Y-axis direction. The sliding portion 16 has a sliding surface 16a. The sliding surface 16a extends in a strip shape with the X-axis direction as its longitudinal direction. The sliding portion 32 has a sliding surface 32a. The sliding surface 32a is in surface contact with the sliding surface 16a via a lubricant. In this configuration, the sliding portion 32 is guided in the X-axis direction by the bed 12 (sliding portion 16).

[0110] A temperature sensor 81 (81X) is provided in the sliding portion 32. The temperature sensor 81 (81X) is embedded in the sliding portion 32. The temperature sensor 81 (81X) is embedded in a position spaced apart from the sliding surface 32a in the Y-axis direction. The distance between the temperature sensor 81 (81X) and the sliding surface 32a in the Y-axis direction may be 3 mm or less, 5 mm or less, 10 mm or less, or 30 mm or less. The temperature sensor 81 (81X) detects the temperature of the sliding portion 32.

[0111] To summarize the structure of machine tool 200 according to the second embodiment of the present invention as described above, machine tool 200 according to the present embodiment includes base 10, movable body 30 having sliding part 32 as a guide part guided by base 10 and movable relative to base 10, temperature sensor 81 provided on sliding part 32 and detecting the temperature of sliding part 32, servo motor 141 serving as a power source for moving movable body 30, and control device 120 that controls servo motor 141 based on a position command indicating a target movement position of movable body 30. Control device 120 corrects the position command based on the temperature of sliding part 32 detected by temperature sensor 81.

[0112] According to machine tool 200 configured in this manner according to the second embodiment of the present invention, it is possible to achieve the same effects as those described in the first embodiment.

[0113] (Embodiment 3) Fig. 11 is a perspective view showing a modified example of the mounting position of the temperature sensor in the guide mechanism in Fig. 2 in a machine tool according to the third embodiment of the present invention. Referring to Fig. 11, the mounting position of temperature sensor 81 may be any position as long as it can detect the temperature of slider 65.

[0114] The temperature sensor 81 may be attached to the main body 66. The temperature sensor 81 may be attached to a side surface of the main body 66 facing the X-axis direction, or may be attached to a side surface of the main body 66 facing the Z-axis direction. With this configuration, even if the distance between the slider 65J and the slider 65K is small, it is possible to ensure space for attaching the temperature sensor 81.

[0115] (Fourth embodiment) The machine tool in this embodiment has a partially similar configuration to machine tool 100 in embodiment 1. Hereinafter, description of the overlapping configuration will not be repeated.

[0116] Fig. 12 is a side view showing a machine tool according to a fourth embodiment of the present invention. Fig. 13 is a diagram showing the functional configuration of a control system of the machine tool in Fig. 12. Fig. 14 is a table showing the coefficient table in Fig. 13.

[0117] 12 to 14, the machine tool in this embodiment has temperature sensor 81X and temperature sensor 81Z as temperature sensor 81. Temperature sensor 81X is provided on slider 65 of linear guide 51X and detects X-axis slider temperature Tx. Temperature sensor 81Z is provided on slider 65 of linear guide 51Z and detects Z-axis slider temperature Tz.

[0118] The slider 65 has a mounting surface 211. The mounting surface 211 is a surface on which an object to be guided by the slider 65 is attached. In the slider 65 of the linear guide 51X, the column 31 is attached to the mounting surface 211. The mounting surface 211 is a plane perpendicular to the Y-axis direction. In the slider 65 of the linear guide 51Z, the table 41 is attached to the mounting surface 211. The mounting surface 211 is a plane perpendicular to the Y-axis direction.

[0119] In this embodiment, the X-axis slider temperature Tx and the Z-axis slider temperature Tz, which are the slider temperatures perpendicular to the axes, are used to correct the position command indicating the target movement position of the spindle head 22 moving in the Y-axis direction (Y-axis position correction).

[0120] 13 and 14, a coefficient table 201 is stored in the storage unit 156. The position command corrector 161 has a thermal change amount calculator 162Y. The thermal change amount calculator 162Y calculates the thermal change amounts dxy and dzy in the Y-axis direction, which will be described below.

[0121] The thermal change amount calculation unit 162Y reads out the coefficient table 201 from the storage unit 156. The thermal change amount calculation unit 162Y refers to the coefficient table 201 to identify the coefficient Sxy to be applied to the Y-axis position correction using the X-axis slider temperature Tx and the coefficient Szy to be applied to the Y-axis position correction using the Z-axis slider temperature Tz.

[0122] The thermal displacement calculation unit 162Y calculates the thermal displacement dxy in the Y-axis direction due to heat generation of the slider 65 of the linear guide 51X by substituting the X-axis slider temperature Tx, the machine body temperature t, and the coefficient Sxy into the formula (Tx-t)×Sxy. The thermal displacement dxy is mainly caused by the slider 65 of the linear guide 51X generating heat as the column 31 moves in the X-axis direction, and the heat being transferred to the column 31 through the mounting surface 211 of the slider 65 of the linear guide 51X, causing thermal expansion of the column 31 in the Y-axis direction perpendicular to the mounting surface 211 of the slider 65 of the linear guide 51X.

[0123] The thermal displacement calculation unit 162Y calculates the thermal displacement dzy in the Y-axis direction due to heat generation of the slider 65 of the linear guide 51Z by substituting the Z-axis slider temperature Tz, the machine body temperature t, and the coefficient Szy into the formula (Tz-t)×Szy. The thermal displacement dzy is mainly caused by the slider 65 of the linear guide 51Z generating heat as the table 41 moves in the Z-axis direction, and the heat being transferred to the table 41 through the mounting surface 211 of the slider 65 of the linear guide 51Z, causing thermal expansion of the table 41 in the Y-axis direction, which is perpendicular to the mounting surface 211 of the slider 65 of the linear guide 51Z.

[0124] The coefficient S shown in FIG. 14 is determined in advance through an experiment conducted by an operator at the manufacturer of the machine tool.

[0125] In the experiment, the column 31 was continuously reciprocated in the X-axis direction, causing the slider 65 of the linear guide 51X that guides the column 31 to generate heat. As the slider 65 generated heat, a temperature sensor was used to measure the temperature of the slider 65 of the linear guide 51X and the temperature of the base of the machine tool 100. Furthermore, a measuring instrument such as a digital gauge was used to measure the thermal displacement of the column 31 in the Y-axis direction at each temperature. The coefficient Sxy was determined from the relationship between the measured temperature and the measured amount of thermal displacement. Furthermore, the table 41 was continuously reciprocated in the Z-axis direction, causing the slider 65 of the linear guide 51Z that guides the table 41 to generate heat. As the slider 65 generated heat, a temperature sensor was used to measure the temperature of the slider 65 of the linear guide 51Z and the temperature of the base of the machine tool 100. Furthermore, a measuring instrument such as a digital gauge was used to measure the thermal displacement of the table 41 in the Y-axis direction at each temperature. The coefficient Szy was determined from the relationship between the measured temperature and the measured amount of thermal displacement.

[0126] The correction execution unit 163 calculates a corrected position command py based on the thermal change amount dxy and the thermal change amount dzy (py=Py-dxy+dzy).

[0127] As shown by arrow 310 in Fig. 12, column 31 thermally expands in the +Y-axis direction due to heat from slider 65 of linear guide 51X, and the contact point of tool T on workpiece W is displaced in the +Y-axis direction. In this case, the correction direction of position command Py for spindle head 22 based on thermal displacement amount dxy should be set to the -Y-axis direction. As shown by arrow 320 in Fig. 12, table 41 thermally expands in the +Y-axis direction due to heat from slider 65 of linear guide 51Z, and the contact point of tool T on workpiece W is displaced in the -Y-axis direction. In this case, the correction direction of position command Py for spindle head 22 based on thermal displacement amount dzy should be set to the +Y-axis direction.

[0128] The correction execution unit 163 outputs the calculated corrected position command py to the servo motor 141Y.

[0129] To summarize the configuration of the machine tool in embodiment 4 of the present invention described above, the machine tool in this embodiment has a movable body, a guide rail 61, a slider 65 attached to the movable body and slidable along the guide rail 61, a linear guide 51 (51X / 51Z) that guides the movable body in its movement direction, and a temperature sensor 81 (81X / 81Z) provided on the slider 65 that detects the temperature of the slider 65.

[0130] The movable body includes a first movable body (column 31 / table 41) that moves in a first direction (X-axis direction / Z-axis direction). The linear guide 51 (51X / 51Z) has a slider 65 with a mounting surface 211 to which the first movable body (column 31 / table 41) is attached, and guides the first movable body (column 31 / table 41) in the first direction (X-axis direction / Z-axis direction). The movable body further includes a second movable body (spindle head 22) that moves in a second direction (Y-axis direction) that is perpendicular to the mounting surface 211 and perpendicular to the first direction (X-axis direction / Z-axis direction). The machine tool further includes a servo motor 141Y that serves as a power source for moving the second movable body (spindle head 22), and a control device 120 that controls the servo motor 141Y based on a position command that indicates a target movement position of the second movable body (spindle head 22). The control device 120 corrects a position command indicating a target movement position of the second moving body (spindle head 22) based on the temperature of the slider 65 detected by the temperature sensors 81X / 81Z.

[0131] Moreover, the machine tool in this embodiment is equipped with: a first movable body (column 31 / table 41) that moves in a first direction (X-axis direction / Z-axis direction); a slider 65 having an attachment surface 211 to which the first movable body (column 31 / table 41) is attached; linear guides 51X / 51Z that guide the first movable body (column 31 / table 41) in the first direction (X-axis direction / Z-axis direction); temperature sensors 81X / 81Z that are provided on the slider 65 and detect the temperature of the slider 65; a second movable body (spindle head 22) that moves in a second direction (Y-axis direction) that is perpendicular to the attachment surface 211 and perpendicular to the first direction (X-axis direction / Z-axis direction); a servo motor 141Y that serves as a power source for moving the second movable body (spindle head 22); and a control device 120 that controls the servo motor 141Y based on a position command that indicates a target movement position of the second movable body (spindle head 22). The control device 120 corrects a position command indicating a target movement position of the second moving body (spindle head 22) based on the temperature of the slider 65 detected by the temperature sensors 81X / 81Z.

[0132] With this configuration, even if the first moving body (column 31 / table 41) thermally expands in the second direction (Y-axis direction) due to heat generation from the slider 65 that guides the first moving body (column 31 / table 41), the position command indicating the target movement position of the second moving body (spindle head 22) moving in the second direction (Y-axis direction) can be corrected based on the temperature of the slider 65, thereby making it possible to position the second moving body (spindle head 22) with respect to its target movement position with higher accuracy.

[0133] (Embodiment 5) The machine tool in this embodiment has a partially similar configuration to machine tool 100 in embodiment 1. Hereinafter, description of the overlapping configuration will not be repeated.

[0134] Fig. 15 is a side view showing a machine tool in a fifth embodiment of the present invention. Fig. 16 is a diagram showing the functional configuration of a control system of the machine tool in Fig. 15. Fig. 17 is a table showing the coefficient table in Fig. 16.

[0135] 15 to 17, the machine tool in this embodiment has a temperature sensor 81Y as temperature sensor 81. Temperature sensor 81Y is provided on slider 65 of linear guide 51Y and detects Y-axis slider temperature Ty. Spindle head 22 is attached to mounting surface 211 of slider 65 of linear guide 51Y. Mounting surface 211 is a plane perpendicular to the Z-axis direction.

[0136] In this embodiment, the Y-axis slider temperature Ty as the axis-orthogonal direction slider temperature is used to correct a position command indicating a target movement position of the table 41 moving in the Z-axis direction (Z-axis position correction).

[0137] 16 and 17, the storage unit 156 stores a coefficient table 202. The position command corrector 161 has a thermal change amount calculator 162Z. The thermal change amount calculator 162Z calculates a thermal change amount dyz in the Z-axis direction, which will be described below.

[0138] The thermal change amount calculation unit 162Z reads out the coefficient table 202 from the storage unit 156. The thermal change amount calculation unit 162Z refers to the coefficient table 202 and identifies the coefficient Syz to be applied to the Z-axis position correction using the Y-axis slider temperature Ty.

[0139] Thermal displacement calculation unit 162Z calculates the thermal displacement dyz in the Z-axis direction due to heat generation from slider 65 of linear guide 51Y by substituting Y-axis slider temperature Ty, machine body temperature t, and coefficient Syz into the formula (Ty-t)×Syz. The thermal displacement dyz is mainly caused by the slider 65 of linear guide 51Y generating heat as spindle head 22 moves in the Y-axis direction, and the heat being transferred to spindle head 22 through mounting surface 211 of slider 65 of linear guide 51Y, causing thermal expansion of spindle head 22 in the Z-axis direction, which is perpendicular to mounting surface 211 of slider 65 of linear guide 51Y.

[0140] The coefficient S shown in FIG. 17 is determined in advance through an experiment conducted by an operator at the manufacturer of the machine tool.

[0141] In the experiment, the spindle head 22 was caused to continuously reciprocate in the Y-axis direction, causing the slider 65 of the linear guide 51Y that guides the spindle head 22 to generate heat. As the slider 65 generated heat, a temperature sensor was used to measure the temperature of the slider 65 of the linear guide 51Y and the temperature of the base of the machine tool 100, and furthermore, a measuring instrument such as a digital gauge was used to measure the amount of thermal displacement in the Z-axis direction of the spindle head 22 at each temperature. The coefficient Syz was determined from the relationship between the measured temperature value and the measured amount of thermal displacement.

[0142] The correction execution unit 163 calculates the corrected position command pz based on the thermal change amount dyz (pz=Pz+dyz).

[0143] 15, the spindle head 22 receives heat from the slider 65 of the linear guide 51Y and thermally expands in the +Z-axis direction, displacing the contact point of the tool T on the workpiece W in the +Z-axis direction. In this case, the correction direction of the position command Pz of the table 41 based on the thermal displacement amount dyz can be set to the +Z-axis direction.

[0144] The correction execution unit 163 outputs the calculated corrected position command pz to the servo motor 141Z.

[0145] To summarize the configuration of the machine tool in embodiment 5 of the present invention described above, the machine tool in this embodiment has a movable body, a guide rail 61, a slider 65 attached to the movable body and slidable along the guide rail 61, a linear guide 51 (51Y) that guides the movable body in its movement direction, and a temperature sensor 81 (81Y) provided on the slider 65 that detects the temperature of the slider 65.

[0146] The movable body includes a first movable body (spindle head 22) that moves in a first direction (Y-axis direction). The linear guide 51 (51Y) has a slider 65 with a mounting surface 211 to which the first movable body (spindle head 22) is attached, and guides the first movable body (spindle head 22) in the first direction (Y-axis direction). The movable body further includes a second movable body (table 41) that moves in a second direction (Z-axis direction) that is perpendicular to the mounting surface 211 and perpendicular to the first direction (spindle head 22). The machine tool includes a servo motor 141Z that serves as a power source for moving the second movable body (table 41), and a control device 120 that controls the servo motor 141Z based on a position command that indicates a target movement position of the second movable body (table 41). The control device 120 corrects the position command that indicates the target movement position of the second movable body (table 41) based on the temperature of the slider 65 detected by a temperature sensor 81Y.

[0147] The machine tool in this embodiment also includes a first movable body (spindle head 22) that moves in a first direction (Y-axis direction), a linear guide 51Y that has a slider 65 with a mounting surface 211 to which the first movable body (spindle head 22) is attached and that guides the first movable body (spindle head 22) in the first direction (Y-axis direction), a temperature sensor 81Y that is attached to the slider 65 and detects the temperature of the slider 65, a second movable body (table 41) that moves in a second direction (Z-axis direction) that is perpendicular to the mounting surface 211 and perpendicular to the first direction (Y-axis direction), a servo motor 141Z that serves as a power source for moving the second movable body (table 41), and a control device 120 that controls the servo motor 141Z based on a position command that indicates a target position of the second movable body (table 41). The control device 120 corrects the position command that indicates the target position of the second movable body (table 41) based on the temperature of the slider 65 detected by the temperature sensor 81Y.

[0148] With this configuration, even if the first moving body (spindle head 22) thermally expands in the second direction (Z-axis direction) due to heat generation from the slider 65 that guides the first moving body (spindle head 22), the second moving body (table 41) can be positioned with higher accuracy relative to its target movement position by correcting the position command that indicates the target movement position of the second moving body (table 41) that moves in the second direction (Z-axis direction) based on the temperature of the slider 65.

[0149] (Sixth embodiment) The machine tool in this embodiment has a configuration that combines the machine tool in embodiment 4 and the machine tool in embodiment 5. Hereinafter, description of the overlapping configuration will not be repeated.

[0150] Fig. 18 is a side view showing a machine tool in a sixth embodiment of the present invention. Fig. 19 is a diagram showing the functional configuration of a control system of the machine tool in Fig. 18. Fig. 20 is a table showing the coefficient table in Fig. 19.

[0151] 18 to 20, the machine tool in this embodiment has temperature sensor 81X, temperature sensor 81Y, and temperature sensor 81Z as temperature sensor 81. As shown in FIGS. 19 and 20, memory unit 256 stores coefficient table 203. Coefficient table 203 includes coefficient Sxy applied to Y-axis position correction using X-axis slider temperature Tx, coefficient Szy applied to Y-axis position correction using Z-axis slider temperature Tz, and coefficient Syz applied to Z-axis position correction using Y-axis slider temperature Ty.

[0152] In this embodiment, the X-axis slider temperature Tx and the Z-axis slider temperature Tz as the axis-orthogonal direction slider temperatures are used to correct a position command indicating a target movement position of the spindle head 22 moving in the Y-axis direction (Y-axis position correction), as described in the fourth embodiment. Also, the Y-axis slider temperature Ty as the axis-orthogonal direction slider temperature is used to correct a position command indicating a target movement position of the table 41 moving in the Z-axis direction (Z-axis position correction), as described in the fifth embodiment.

[0153] According to this configuration, the effects described in the fourth and fifth embodiments can be similarly achieved.

[0154] The machine tool of the present invention may be configured by arbitrarily combining the configurations of the machine tools described in the first to sixth embodiments.

[0155] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0156] 10 base body, 12 bed, 16, 32 sliding part, 16a, 32a sliding surface, 21 spindle, 22 spindle head, 30 moving body, 31 column, 41 table, 51, 51A, 51B, 51X, 51Y, 51Z linear guide, 61 guide rail, 65, 65J, 65K slider, 66 main body part, 67, 67p, 67q resin part, 68 hole, 71 linear scale, 72 scale part, 73 base part, 74 scale main body, 75 cover, 76 head part, 81, 81X, 81Y, 81Z, 82 temperature sensor, 100, 200 machine tool, 101 rotation center axis, 120 control device, 131 program analysis part, 132 position command part, 133 Motor control unit, 141, 141X, 141Y, 141Z servo motor, 151 temperature data acquisition unit, 156 memory unit, 157, 201, 202, 203 coefficient table, 161 position command correction unit, 162X, 162Y, 162Z thermal displacement calculation unit, 163 correction execution unit, 211 mounting surface.

Claims

1. A moving object and a linear guide including a guide rail and a slider attached to the moving body and slidable along the guide rail, and guiding the moving body in its moving direction; a temperature sensor provided on the slider to detect a temperature of the slider.

2. a servo motor serving as a power source for moving the moving body; a control device that controls the servo motor based on a position command indicating a target movement position of the moving body, the control device corrects the position command based on the temperature of the slider detected by the temperature sensor; The moving body is a first moving body that moves in a first direction; a second moving body that moves in a second direction perpendicular to the first direction; a third moving body that moves in a third direction perpendicular to the first direction and the second direction, The linear guide is a first linear guide that guides the first movable body in the first direction; a second linear guide that guides the second movable body in the second direction; a third linear guide that guides the third movable body in the third direction, The temperature sensor a first temperature sensor that detects the temperature of the slider of the first linear guide; a second temperature sensor that detects the temperature of the slider of the second linear guide; a third temperature sensor that detects the temperature of the slider of the third linear guide, 2. The machine tool according to claim 1, wherein the control device corrects the position command indicating a target movement position of the first movable body based on the temperature of the slider of the first linear guide detected by the first temperature sensor, the temperature of the slider of the second linear guide detected by the second temperature sensor, and the temperature of the slider of the third linear guide detected by the third temperature sensor.

3. The slider is a metal body that engages with the guide rail via rolling elements; a resin portion made of resin, the resin portion being adjacent to the main body portion in the movement direction of the movable body and connected to the main body portion, The machine tool according to claim 1 or 2, wherein the temperature sensor is supported by the resin portion so as to be in contact with the main body portion.

4. the moving body includes a first moving body that moves in a first direction; the linear guide includes the slider having a mounting surface to which the first moving body is attached, and guides the first moving body in the first direction; The movable body further includes a second movable body that moves in a second direction that is perpendicular to the mounting surface and perpendicular to the first direction, and a servo motor serving as a power source for moving the second moving body; a control device that controls the servo motor based on a position command that indicates a target movement position of the second moving body, The machine tool according to claim 1 , wherein the control device corrects the position command indicating a target movement position of the second movable body based on the temperature of the slider detected by the temperature sensor.

5. the first moving body is a column or a table that moves in a horizontal direction, 5. The machine tool according to claim 4, wherein the second movable body is a spindle head that moves in a vertical direction.

6. the first movable body is a spindle head that moves in a vertical direction, The machine tool according to claim 4 , wherein the second movable body is a table that moves in a horizontal direction.

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