JP2020062705A - Machine tool, program and correction amount calculation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform thermal displacement correction satisfactorily from the start of machining of a work, and to perform thermal displacement correction in consideration of thermal displacement occurring in a configuration other than a slide portion. A machine tool 1 detects a first X-axis slide unit 45 that adjusts a relative position between a work W and a tool in the X-axis direction, a detection unit that detects that a dog D1 and a detection unit Sp1 are in contact with each other. A calculation means for acquiring the X coordinate of the first X-axis slide unit 45 at the time of detection of the means, acquiring the detected temperature detected by the temperature sensor St1, and calculating the correction amount for correcting the thermal displacement in the X-axis direction. Be prepared. The calculation means calculates a first value indicating the amount of thermal displacement based on the acquired plurality of X coordinates, and calculates a second value indicating an estimated value of the amount of thermal displacement based on the detected temperature. The calculation means calculates the correction amount using the first value within a predetermined period from the start of machining of the work W, and calculates the correction amount using the second value after the lapse of the predetermined period. [Selection diagram] Fig. 3

Description

  The present invention relates to a machine tool, a program, and a correction amount calculation method.

  As a conventional machine tool, Patent Document 1 includes a slide part that is movable in a predetermined axial direction in order to adjust the relative position between a work (workpiece) and a tool, and thermal displacement in the moving direction of the slide part. A machine tool is disclosed which performs correction based on the output of a touch switch.

  Further, Patent Document 2 discloses a machine tool that corrects thermal displacement of a shaft to be corrected based on the output of a temperature sensor embedded in a predetermined portion.

Patent No. 5883264 Japanese Patent No. 3136472

  With the technique using the touch switch provided corresponding to the slide portion as in Patent Document 1, it is difficult to correct the thermal displacement in consideration of the thermal displacement that occurs in another unit that does not move together with the slide portion (such as the headstock).

  On the other hand, with the technique using a temperature sensor as in Patent Document 2, it is possible to perform thermal displacement correction in consideration of thermal displacement that occurs in other units, but as shown in FIG. It is difficult to correct the rapid thermal displacement that occurs in a few minutes). This is because heat is not sufficiently transmitted to the portion where the temperature sensor is embedded during the predetermined period, and a difference occurs between the actual temperature to be corrected and the temperature detected by the temperature sensor.

  The present invention has been made in view of the above circumstances, and is capable of favorably performing thermal displacement correction from the start of machining a workpiece, and performing thermal displacement correction in consideration of thermal displacement that occurs in a configuration other than the slide portion. It is an object of the present invention to provide a machine tool, a program, and a correction amount calculation method that enable

In order to achieve the above object, the machine tool according to the first aspect of the present invention is
A slide unit that moves in a predetermined axial direction with respect to the base and that adjusts the relative position in the axial direction of the work held by the spindle and the tool for processing the work,
A detection unit that detects that the moving unit that moves in the axial direction together with the slide unit and the immovable unit that does not move in the axial direction come into contact with each other or that they approach each other by a predetermined distance,
The axial position, which is the axial position of the slide portion at the time of detection, is acquired based on the detection by the detection means, and the detected temperature detected by the temperature sensor provided at a predetermined location is acquired and acquired. Calculation means for calculating a correction amount for correcting the thermal displacement in the axial direction based on at least one of the axial position and the detected temperature;
Drive control means for moving the slide portion to a position in which the correction amount is added to the target position,
The calculation means is
A first value indicating the amount of thermal displacement is calculated based on a plurality of axial positions acquired at different detections, and a second value indicating an estimated value of the amount of thermal displacement is calculated based on the detected temperature. Then
The correction amount is calculated using the first value within a predetermined period from the start of machining the work, and the correction amount is calculated using the second value after the predetermined period has elapsed.

The machine tool further includes a tool part having a hollow part through which a work can be passed and a tool whose tip faces the hollow part.
The tool part is movable in the axial direction together with the slide part,
The axial direction is the radial direction of the work,
The moving portion and the immovable portion may be located outside the hollow portion in the axial direction.

  The moving part and the immovable part may be in a position that does not overlap the tool part in the axial direction.

The immovable portion is a contact sensor located outside the slide portion in the axial direction,
The detection unit may detect that the moving unit has contacted the contact sensor.

The calculating means obtains the detected temperature from each of the plurality of temperature sensors,
The plurality of temperature sensors include a temperature sensor that detects an ambient temperature of a ball screw for moving the slide portion in the axial direction, and a temperature sensor that detects an ambient temperature of a configuration other than the ball screw. You may

  The calculation means may calculate the correction amount by using not only the first value but also the second value within the predetermined period.

In order to achieve the above object, a program according to a second aspect of the present invention is
A slide unit that moves in a predetermined axial direction with respect to the base and that adjusts the relative position in the axial direction of the work held by the spindle and the tool for processing the work,
The shaft in a machine tool, comprising: a moving unit that moves in the axial direction together with the slide unit; and a detection unit that detects that a non-moving unit that does not move in the axial direction contacts or approaches a predetermined distance. A program for calculating the correction amount according to the thermal displacement in the direction,
On the computer,
A process of acquiring an axial position that is the axial position of the slide portion at the time of detection based on what the detection means detects;
A process of acquiring a detected temperature detected by a temperature sensor provided at a predetermined location of the machine tool,
And a calculation process of calculating a correction amount for correcting the thermal displacement based on at least one of the acquired axial position and the detected temperature,
In the calculation process,
A first value indicating the amount of thermal displacement is calculated based on a plurality of axial positions acquired at different detections, and a second value indicating an estimated value of the amount of thermal displacement is calculated based on the detected temperature. Then
The correction amount is calculated using the first value within a predetermined period from the start of machining the work, and the correction amount is calculated using the second value after the predetermined period has elapsed.

In order to achieve the above object, a correction amount calculation method according to a third aspect of the present invention is
A slide unit that moves in a predetermined axial direction with respect to the base and that adjusts the relative position in the axial direction of the work held by the spindle and the tool for processing the work,
The shaft in a machine tool, comprising: a moving unit that moves in the axial direction together with the slide unit; and a detection unit that detects that a non-moving unit that does not move in the axial direction contacts or approaches a predetermined distance. A correction amount calculation method for calculating a correction amount according to a thermal displacement in a direction,
Acquiring the axial position which is the axial position of the slide portion at the time of detection based on the detection by the detection means,
Acquiring a detected temperature detected by a temperature sensor provided at a predetermined location of the machine tool,
A calculation step of calculating a correction amount for correcting the thermal displacement based on at least one of the acquired axial position and the detected temperature,
In the calculation step,
A first value indicating the amount of thermal displacement is calculated based on a plurality of axial positions acquired at different detections, and a second value indicating an estimated value of the amount of thermal displacement is calculated based on the detected temperature. Then
The correction amount is calculated using the first value within a predetermined period from the start of machining the work, and the correction amount is calculated using the second value after the predetermined period has elapsed.

  According to the present invention, it is possible to favorably perform thermal displacement correction from the start of machining a workpiece, and also possible to perform thermal displacement correction in consideration of thermal displacement that occurs in a configuration other than the slide portion.

It is the schematic diagram which looked at the machine tool which concerns on one Embodiment of this invention from the X-axis direction. (A) is the figure which looked at the 1st processing mechanism mainly from the Z-axis direction. (B) is the figure which looked at the 2nd processing mechanism from the Z-axis direction. It is the figure which looked at the machine tool from the Y-axis direction. It is a figure which shows the example of installation of a temperature sensor. It is the figure which looked at the machine tool from the X-axis direction, and is a figure mainly for demonstrating the installation location of a predetermined temperature sensor. It is a flow chart of reference position acquisition processing. It is a flowchart of a thermal displacement correction process. It is a figure for demonstrating the period when it becomes difficult to correct thermal displacement, which has occurred in the technology using the conventional temperature sensor.

  A machine tool according to an embodiment of the present invention will be described with reference to the drawings. The machine tool 1 shown in FIG. 1 is configured as a multi-function lathe that processes the front surface and the back surface of a cylindrical workpiece (work) W with two spindles.

  In order to facilitate understanding of the description below, the horizontal direction along the center line of the work W is referred to as the “Z-axis direction”, the vertical direction is referred to as the “Y-axis direction”, and the horizontal direction perpendicular to the Y-axis and the Z-axis direction. The direction is called "X-axis direction". In addition, the direction in which the arrow points in each of the X, Y, and Z axes indicated by the arrow in the drawing is the + side.

  As shown in FIG. 1, the machine tool 1 mainly includes a bed 2, which is a platform of the machine tool 1, a first machining mechanism M1, a second machining mechanism M2, a detection mechanism 200, and a temperature sensor St (see FIG. 4) and the control unit 300.

(First processing mechanism M1)
The first machining mechanism M1 is a mechanism for machining the front surface (the surface facing the + Z axis direction) and the side surface of the work W, and includes a work holding unit 20, a first Z axis slide mechanism 30, and a tool moving mechanism 40. .

  The work holding unit 20 includes a spindle 21 and a spindle stock 22 that rotatably supports the spindle 21. A work rotating motor (not shown) is built in the headstock 22. The work rotating motor rotates the work W held by the chuck 21 a provided on the main shaft 21.

The first Z-axis slide mechanism 30 is a mechanism for moving the work holding unit 20 in the Z-axis direction, and includes a bearing unit 31 mounted on the bed 2 and a Z-axis direction supported by the bearing unit 31. A ball screw 32, a first Z-axis motor 33 that rotates the ball screw 32, and a first Z-axis slide portion 34 on which the headstock 22 is installed are provided. The first Z-axis slide portion 34 has a nut 35 that fits with the ball screw 32. The nut 35 moves in the Z-axis direction when the ball screw 32 rotates.
The first Z-axis slide mechanism 30 rotates the ball screw 32 with the first Z-axis motor 33 to move the first Z-axis slide part 34 together with the nut 35 and move the work holding part 20 in the Z-axis direction. Therefore, in the first machining mechanism M1, the work W can be moved in the Z-axis direction while being held by the chuck 21a and being rotated by the work rotation motor.

  The tool moving mechanism 40 is a mechanism for moving the tool Tf (see FIG. 2A) for processing the work W in the X-axis direction and the Y-axis direction, and includes a fixed base 41 fixed to the bed 2. An X-axis moving unit 44 provided on the fixed base 41 and a Y-axis moving unit 50 provided on the X-axis moving unit 44 are provided.

  The fixed base 41 includes a rail portion Rx1 extending in the X-axis direction, a hollow flange 43a attached to the hollow portion 41H penetrating in the Z-axis direction, and a guide bush 43b attached to the inner surface of the flange 43a. The guide bush 43b assists in holding and moving the work W. Further, the fixed base 41 includes the first X-axis slide mechanism 10 as shown in FIG.

  The first X-axis slide mechanism 10 is a mechanism for moving the X-axis moving unit 44 in the X-axis direction, and includes the bearing unit 11 attached to the fixed base 41 and the bearing unit 11 axially supported in the X-axis direction. The ball screw 12 extends and a first X-axis motor 13 that rotates the ball screw 12 is provided. The nut 15 fitted with the ball screw 12 moves in the X-axis direction when the ball screw 12 rotates. The first X-axis slide mechanism 10 rotates the ball screw 12 by the first X-axis motor 13 to move the later-described first X-axis slide portion 45 provided with the nut 15 in the X-axis direction.

  The X-axis moving portion 44 is a portion that moves in the X-axis direction on the rail portion Rx1 by the first X-axis slide mechanism 10, and includes the first X-axis slide portion 45, the guide groove portion Gx1, the bearing portion 46, the ball screw 47, And a Y-axis motor 48.

  The first X-axis slide portion 45 has a substantially flat plate shape. The ball screw 47 is housed inside the first X-axis slide portion 45 as shown in FIG. The guide groove portion Gx1 extends in the X-axis direction and is provided on one surface of the substantially flat plate shape. The guide groove portion Gx1 engages with the rail portion Rx1 of the fixed base 41. As shown in FIG. 3, a guide groove portion Gy1 extending in the Y-axis direction is provided on the other surface of the substantially flat plate shape. The guide groove portion Gy1 guides the movement of the Y-axis moving portion 50 in the Y-axis direction. The first X-axis slide portion 45 is formed with a hollow portion 45H through which the work W gripped by the main shaft 21 can pass. The bearing 46 rotatably supports a ball screw 47, and the ball screw 47 rotatably supported in this manner is arranged so as to extend in the Y-axis direction and is rotated by a Y-axis motor 48.

  The Y-axis moving portion 50 is a portion that moves in the Y-axis direction along the guide groove portion Gy1, and includes a Y-axis slide portion 51, a tool holding portion 52 and a nut 53 provided on the Y-axis slide portion 51. . Since the Y-axis moving unit 50 is provided in the X-axis moving unit 44, when the X-axis moving unit 44 moves in the X-axis direction by the first X-axis slide mechanism 10, the Y-axis moving unit 50 also moves in the X-axis direction. Move to.

The Y-axis slide portion 51 has a substantially flat plate shape. A hollow portion 51H through which the work W gripped by the main shaft 21 can pass is formed on the substantially flat plate-shaped main surface (a surface parallel to the Y axis).
The tool holding portion 52 is provided on the main surface of the Y-axis slide portion 51. As shown in FIG. 2A, the tool holding portion 52 is arranged along the left and right ends of the hollow portion 51H. The tool holding unit 52 holds a tool Tf including a plurality of cutting tools, a drill and the like. The tool Tf is, for example, as shown in FIG. 2A, nine bites facing the X-axis direction and the center of the hollow portion 51H, and four drills facing the -Z axis direction (indicated by dotted lines in FIG. 2). (Shown), and. The cutting tool forming the tool Tf includes a cutting tool for cutting the work W. Further, the front surface of the work W can be processed by the drill forming the tool Tf.
A rail portion Ry1 extending along the Y-axis direction is provided on the rear surface of the surface of the Y-axis slide portion 51 on which the tool holding portion 52 is provided. The rail portion Ry1 is slidable in the guide groove portion Gy1 provided in the first X-axis slide portion 45.
The first machining mechanism M1 rotates the ball screw 47 with the Y-axis motor 48, thereby moving the nut 53 fitted with the ball screw 47, thereby moving the Y-axis moving unit 50 in the Y-axis direction.

  With the above configuration, the X-axis moving unit 44 and the Y-axis moving unit 50 of the tool moving mechanism 40 can move in the X-axis direction and the Y-axis direction, respectively. Along with this, the tool Tf is also movable in the X-axis and Y-axis directions.

(Second processing mechanism M2)
The second processing mechanism M2 is a mechanism for processing the back surface (the surface facing the −Z axis direction) and side surface of the work W, and includes the work holding unit 70, the second Z axis slide mechanism 80, and the second X axis slide mechanism 90. , Tool base 100.

  The work holding unit 70 includes a spindle 71 and a spindle stock 72 that rotatably supports the spindle 71. A work rotation motor (not shown) is built in the headstock 72. The work rotating motor rotates the work W held by the chuck 71 a provided on the main shaft 71. The headstock 72 is installed on a second X-axis slide portion 91 of the second X-axis slide mechanism 90, which will be described later.

The second Z-axis slide mechanism 80 is a mechanism for moving the work holding unit 70 in the Z-axis direction, and includes a bearing portion 81 and a bearing portion 61 provided on a fixed base 60 fixed on the bed 2, and a bearing portion. 81, a ball screw 82 axially supported by the bearing portion 61 and extending in the Z-axis direction, a second Z-axis motor 83 for rotating the ball screw 82, and a second Z-axis slide portion 84 on which a second X-axis slide mechanism 90 is installed. As shown in FIG. 3, a rail portion Rz2 provided on the fixed base 60 is provided. The bearing 81 receives the ball screw 82 on the side of the second Z-axis motor 83, and the bearing 61 receives the tip of the ball screw 82.
The second Z-axis slide portion 84 has a nut 85 that fits with the ball screw 82 and a guide groove portion Gz2 (see FIG. 2B) that extends in the Z-axis direction. The nut 85 moves in the Z-axis direction when the ball screw 82 rotates. The guide groove portion Gz2 engages with the rail portion Rz2.
The second Z-axis slide mechanism 80 moves the second Z-axis slide portion 84 together with the nut 85 by rotating the ball screw 82 with the second Z-axis motor 83. As a result, the work holding unit 70 can move on the rail portion Rz2 extending in the Z-axis direction.

The second X-axis slide mechanism 90 is a mechanism for moving the work holding unit 70 in the X-axis direction, and as shown in FIG. 2B, etc., the second X-axis slide unit 91 and the second Z-axis slide unit 84. A bearing portion 92 provided above, a ball screw 93 that is axially supported by the bearing portion 92 and extends in the X-axis direction, and a second X-axis motor 94 that rotates the ball screw 93 are provided.
A headstock 72 is installed on the second X-axis slide portion 91. The second X-axis slide portion 91 has a nut 95 (see FIG. 3) fitted to the ball screw 93 and a guide groove portion Gx2 (see FIG. 1 and FIG. 3) extending in the X-axis direction below the Y-axis direction. The nut 95 moves in the X-axis direction when the ball screw 93 rotates. The guide groove portion Gx2 engages with the rail portion Rx2 as shown in FIG.
The second X-axis slide mechanism 90 moves the second X-axis slide portion 91 together with the nut 95 by rotating the ball screw 93 with the second X-axis motor 94. Accordingly, the work holding unit 70 can move on the rail portion Rx2 extending in the X-axis direction. Since the second X-axis slide mechanism 90 is arranged on the second Z-axis slide mechanism 80, the second Z-axis slide mechanism 80 moves the second Z-axis slide portion 84 in the Z-axis direction to cause the second X-axis slide mechanism to slide. The part 91 also moves in the Z-axis direction.

  With the above configuration, the work W held by the work holding unit 70 is movable in the X-axis and Z-axis directions.

The tool base 100 holds a tool Tr such as a drill, a tap, a turning tool, and a boring tool attached such that the tip thereof is oriented in the + Z axis direction. In the present embodiment, there are a plurality of tools Tr, and for example, as shown in FIG. 3, four tools Tr are provided at a predetermined interval in the X-axis direction, and thus have a comb tooth shape.
As shown in FIG. 2A, the tool base 100 is supported by a support member 101 provided on the bed 2 and is immovable with respect to the bed 2. The tool Tr (see FIG. 3) held by the tool base 100 has its tip (for example, the axis center) positioned at the height at which the work W held by the work holder 70 of the second machining mechanism M2 is positioned at the axis center. It is located in.

(Detection mechanism 200)
The detection mechanism 200 includes detection units Sp1 to Sp3 and dogs D1 to D3. The detection units Sp1 and Sp2 and the dogs D1 and D2 are provided in the first processing mechanism M1. The detection unit Sp3 and the dog D3 are provided in the second processing mechanism M2. Each of the detection units Sp1 to Sp3 is composed of, for example, a touch switch.

  The detection unit Sp1 is provided to measure the thermal displacement in the first X-axis slide mechanism 10 of the first processing mechanism M1 in the X-axis direction (mainly the thermal displacement caused by the ball screw 12 extending in the X-axis direction). There is. Since the ball screw 12 is supported by the first X-axis motor 13, when the heat displacement of the first X-axis motor 13 causes heat displacement, the ball screw 12 extends in the −X-axis direction.

  When the tip portion of the detection unit Sp1 contacts the dog D1, the detection unit Sp1 supplies the control unit 300 with an ON signal indicating the contact. As shown in FIG. 3, the dog D1 is configured as a part of the side surface (the surface facing the −X direction) of the first X-axis slide portion 45. The dog D1 moves in the X-axis direction as the first X-axis slide portion 45 moves. As shown in FIGS. 2 and 3, the detection unit Sp1 is attached to the attachment portion 41a that is pushed out from the fixed base 41. The detection unit Sp1 attached in this manner is immovable with respect to the bed 2 and does not move in the X-axis direction. The detection unit Sp1 and the dog D1 are arranged at positions facing each other in the X-axis direction. The detection unit Sp1 and the dog D1 come into contact with each other when the dog D1 moves by a predetermined amount in the −X axis direction by the movement of the first X-axis slide unit 45.

  In particular, as shown in FIG. 3, the dog D1 (moving part that moves in the X-axis direction together with the first X-axis slide part 45) and the detection part Sp1 (immovable part that does not move in the X-axis direction) are hollow in the X-axis direction. It is located outside the portion 51H. Further, the dog D1 and the detection unit Sp1 are in positions that do not overlap the Y-axis slide unit 51 (an example of a tool unit) in the X-axis direction. That is, the dog D1 and the detection unit Sp1 are located at a position away from the tool Tf facing the work W. By doing so, it is possible to prevent the chips generated during the processing of the work W from adhering to the dog D1 and the detection unit Sp1, and prevent the detection accuracy from decreasing.

  Further, the detection unit Sp1 is located outside the first X-axis slide unit 45 in the X-axis direction. As described above, the detection unit Sp1 that outputs a signal is provided not in a movable portion such as the first X-axis slide unit 45 but in a portion that is immovable with respect to the bed 2, so that vibration applied to the detection unit Sp1 is provided. Can be suppressed, and a decrease in detection accuracy can be prevented.

  The detection unit Sp2 is provided to measure the thermal displacement in the Y-axis direction of the Y-axis moving unit 50 of the first processing mechanism M1 (mainly the thermal displacement caused by the ball screw 47 extending in the Y-axis direction). . Since the ball screw 47 is supported by the Y-axis motor 48, when the Y-axis motor 48 and the like generate heat, the ball screw 47 extends in the −Y-axis direction.

  When the tip portion of the detection unit Sp2 comes into contact with the dog D2, the detection unit Sp2 supplies an ON signal indicating the contact to the control unit 300. As shown in FIG. 1, the dog D2 is provided on the first X-axis slide portion 45 and does not move in the Y-axis direction. As shown in FIG. 1, the detection portion Sp2 is attached to the attachment portion 51a that extends from the Y-axis slide portion 51 in the −Z direction and reaches the back side of the first X-axis slide portion 45. The detection unit Sp2 attached in this manner moves in the Y-axis direction as the Y-axis slide unit 51 moves. The detection unit Sp2 and the dog D2 are arranged at positions facing each other in the Y-axis direction. The detection unit Sp2 and the dog D2 come into contact with each other when the detection unit Sp2 moves in the −Y-axis direction by a predetermined amount due to the movement of the Y-axis slide unit 51.

  The detection unit Sp3 is provided to measure the thermal displacement in the second Z-axis slide mechanism 80 of the second processing mechanism M2 in the Z-axis direction (mainly the thermal displacement caused by the ball screw 82 extending in the Z-axis direction). There is. Since the ball screw 82 is supported by the second Z-axis motor 83, when the heat displacement of the second Z-axis motor 83 or the like causes thermal displacement, the ball screw 82 extends in the −Z-axis direction.

  When the tip portion of the detection unit Sp3 comes into contact with the dog D3, the detection unit Sp3 supplies an ON signal indicating the contact to the control unit 300. As shown in FIG. 3, the dog D3 is provided so as to project from the fixed base 60 in the + X direction. The dog D3 is immovable with respect to the bed 2 and does not move in the Z-axis direction. As shown in FIG. 3, the detection unit Sp3 is attached to a mounting portion 84a that protrudes from the second Z-axis slide portion 84 in the + Z direction. The detection unit Sp3 attached in this way moves in the Z-axis direction as the second Z-axis slide unit 84 moves. The detection unit Sp3 and the dog D3 are arranged at positions facing each other in the Z-axis direction. The detection unit Sp3 and the dog D3 come into contact with each other when the detection unit Sp3 moves by a predetermined amount in the + Z-axis direction by the movement of the second Z-axis slide unit 84.

(Temperature sensor St)
The temperature sensor St is composed of, for example, a thermistor and is provided in plural. The plurality of temperature sensors St outputs to the control unit 300 a signal indicating the detected temperature at each installation location. As shown in FIG. 4, the temperature sensor St is directly inserted into the installation location or is provided (embedded manner) in a metal (for example, stainless steel) block fixed to the installation location. In addition, as an exception, the temperature sensor St8 described later is not provided in a buried state.

  Hereinafter, each of the plurality of temperature sensors St will be denoted by a symbol for each installation location, and will be referred to as temperature sensors St1 to St8. The installation locations of the temperature sensors St1, St4, St7, St8 are shown in FIG. The installation locations of the temperature sensors St2, St3, and St5 are shown in FIG. The installation location of the temperature sensor St6 is shown in FIG.

The temperature sensors St1 to St3 are provided in the first processing mechanism M1.
The temperature sensor St1 detects the ambient temperature of the ball screw 12 extending in the X-axis direction, and is provided, for example, at a position near the bearing portion 11 on the fixed base 41.
The temperature sensor St2 detects the ambient temperature of the ball screw 47 extending in the Y-axis direction, and is provided, for example, at a position near the bearing portion 46 in the first X-axis slide portion 45.
The temperature sensor St3 detects the ambient temperature of the fixed base 41, and is provided, for example, above the cavity 41H of the fixed base 41.

The temperature sensors St4 to St6 are provided in the second processing mechanism M2.
The temperature sensor St4 detects the ambient temperature of the ball screw 93 extending in the X-axis direction, and is provided, for example, at a position near the bearing 92 in the second Z-axis slide portion 84.
The temperature sensor St5 detects the ambient temperature of the ball screw 82 extending in the Z-axis direction, and is provided, for example, in the vicinity of the bearing portion 61 on the fixed base 60.
The temperature sensor St6 detects the ambient temperature of the tool Tr (see FIG. 3) of the tool base 100, and is provided, for example, in the vicinity of the tool base 100 on the support member 101.

The temperature sensor St7 detects the ambient temperature of the bed 2, and is provided on, for example, the leg portion 2a of the bed 2.
The temperature sensor St8 detects a room temperature (that is, the ambient temperature of the machine tool 1 itself), and is provided at a predetermined location in the machine tool 1 in a manner not embedded.

(Control unit 300)
The control unit 300 controls the operation of each unit of the machine tool 1, and includes a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores a program that defines a processing procedure by the CPU, and an appropriate numerical value by the user. A RAM (Random Access Memory) for temporarily storing a program to be executed upon receiving an input and necessary information, a timer for measuring time, and the like are provided. A program PG (see FIG. 1) for executing a “reference position acquisition process” and a “thermal displacement correction process” described below is stored in advance in the ROM of the control unit 300, and the CPU reads these programs. ,Run. The control unit 300 may be one in which the CPU and other dedicated circuits cooperate to control the operation of each unit of the machine tool 1.

  The control unit 300 moves the work holding unit 20 in the Z-axis direction and the tool holding unit 52 in the X-axis and Y-axis directions by numerical control (NC (Numerical Control)) so that the work W and the tool Tf are relatively moved. Appropriate positional relationship. Specifically, the above relationship is realized by driving and controlling the work rotation motor, the first Z-axis motor 33, the first X-axis motor 13, and the Y-axis motor 48 of the first machining mechanism M1. Further, the control unit 300 moves the work holding unit 70 in the X-axis and Z-axis directions by numerical control to appropriately set the relative positional relationship between the work W and the tool Tr. Specifically, the above relationship is realized by driving and controlling the motor for rotating the work of the second machining mechanism M2, the second Z-axis motor 83, and the second X-axis motor 94.

  Next, processing of the work W by the machine tool 1 having the above configuration will be described. In the machine tool 1 according to the present embodiment, first, the first machining mechanism M1 performs the primary machining of the work W, and then, the second machining mechanism M2 further processes the workpiece W that has been subjected to the primary machining (secondary machining). Processing). This processing is performed under the control of the control unit 300.

(About work processing)
(1) Primary Processing The control unit 300 processes a work W by indexing a predetermined tool Tf from the plurality of tools Tf in the tool holding unit 52. Specifically, the Y-axis motor 48 is driven to move the Y-axis moving unit 50 so that the desired tool Tf is located at the same height as the work W. Next, the control unit 300 drives the work rotation motor and the first Z-axis motor 33 to move the work W in the Z-axis direction while rotating the work W, and also drives the first X-axis motor 13 at the same time or with a time difference. Then, the X-axis moving unit 44 is moved toward the work W by the first X-axis slide mechanism 10.
In this way, the tool Tf such as a cutting tool or a drill is brought into contact with the front surface or the side surface of the work W, and the first processing mechanism M1 primarily processes the work W.

(2) Secondary Processing After finishing the primary processing, the control unit 300 drives the second Z-axis motor 83 and the second X-axis motor 94 to move the work holding unit 70 to chuck the work W that has been primarily processed. 71a is grasped. Subsequently, the control unit 300 drives the work rotation motor and the first X-axis motor 13, moves the first X-axis slide unit 45 toward the work W, and uses the cutting tool of the tool Tf to cut the work W to a desired position. Cut at position. Note that FIG. 1 and the like show a state after the work W is cut in this way.
Subsequently, the control unit 300 indexes a predetermined tool Tr from among the plurality of tools Tr of the tool base 100, and grips it with the second Z-axis slide mechanism 80 and the second X-axis slide mechanism 90 while rotating the main spindle 71. The back surface or the side surface of the work W is brought into contact with the selected tool Tr, and the work W is further processed.
In this way, the second machining mechanism M2 secondary-machines the work W.

  As described above, the machine tool 1 that processes the workpiece W, when determining the positions of the predetermined tools Tf and Tr, determines the positions that take into account the “correction amount” according to the thermal displacement of the measurement target in the axial direction. That is, when the relative position between the predetermined tools Tf and Tr and the work W is set as the target position, the target position is set with a correction amount.

  From here, the process for calculating the correction amount will be described. The control unit 300 first executes a “reference position acquisition process” that acquires a reference position that is a reference for obtaining a first thermal displacement amount, which will be described later, and then executes a “thermal displacement correction process”.

  The controller 300 corrects the thermal displacement of the first machining mechanism M1 in the X-axis direction, the thermal displacement of the first machining mechanism M1 in the Y-axis direction, and the thermal displacement of the second machining mechanism M2 in the Z-axis direction. Although possible, the method of correcting thermal displacement in each direction is the same. Therefore, the thermal displacement in the X-axis direction in the first processing mechanism M1 will be mainly described below.

(Reference position acquisition process)
The reference position acquisition process executed by the control unit 300 will be described with reference to the flowchart of FIG. This processing is started, for example, on condition that the power of the machine tool 1 is turned on.

  When the reference position acquisition process is started, the control unit 300 first moves the first X-axis slide unit 45 to the detection standby position (step S11). Specifically, the control unit 300 drives the first X-axis motor 13 to move the first X-axis slide unit 45 to the detection standby position where the dog D1 is close to the tip of the detection unit Sp1. The detection standby position is a position where the dog D1 and the detection unit Sp1 are spaced apart from each other so that the dog D1 and the detection unit Sp1 do not erroneously come into contact with each other due to the reaction of the movement. Is a position where the distance becomes several mm.

  Subsequently, the control unit 300 starts the detection by driving the first X-axis motor 13 and moving the first X-axis slide unit 45 in the -X direction (step S12). As a result, the dog D1 gradually approaches the detection unit Sp1. When the dog D1 comes into contact with the tip of the detection unit Sp1, the detection unit Sp1 supplies a detection signal (ON signal) to the control unit 300. By receiving this detection signal, the control unit 300 detects that the detection unit Sp1 has come into contact with the dog D1, and also acquires the X coordinate at the time when the detection signal is received (step S13), RAM, etc. Remember. The X coordinate acquired here is a coordinate with respect to a predetermined arbitrary origin position (X = 0). The origin position may be, for example, a predetermined position (for example, the tip position of the ball screw 12) when the first X-axis slide portion 45 moves most in the −X-axis direction. For example, the control unit 300 sets the lead of the ball screw 12 (the nut 15 per rotation of the ball screw 12 at the rotation speed (rotation speed = rotation angle / 360 °) of the first X-axis motor 13 at the time of receiving the detection signal. The X coordinate at the time when the detection signal is received is obtained by multiplying the distance (traveling in the X-axis direction). The control unit 300 stores the acquired X coordinate as a reference position. This reference position is used when calculating a first thermal displacement amount described later. After performing the process of step S13, the reference position acquisition process ends.

  Next, the thermal displacement correction process will be described with reference to the flowchart in FIG. 7.

(Thermal displacement correction process)
For example, the control unit 300 starts the thermal displacement correction process on the condition that a signal indicating an instruction to start machining the work W (hereinafter, referred to as a machining start instruction) is received.

  First, the control unit 300 determines whether or not a predetermined period of time has elapsed since receiving the processing start instruction (step S20). The predetermined period is a period (for example, several minutes) longer than the period (see FIG. 8) in which it is difficult to correct the thermal displacement when only the temperature sensor St is used, and is stored in the ROM in advance.

  When the predetermined period has not elapsed (step S20; No), the control unit 300 moves the first X-axis slide unit 45 to the detection standby position, as in step S11 described above (step S21). After that, the control unit 300 executes the processes of steps S21 to S23, and these processes are the same as the above-mentioned steps S11 to S13.

  The control unit 300 acquires the X coordinate at the time when the detection signal is received from the detection unit Sp1 (step S23) and stores it in the RAM or the like to calculate the first thermal displacement amount α (step S24). Specifically, the control unit 300 calculates, as the first thermal displacement amount α, a value obtained by subtracting the X coordinate as the reference position acquired in step S13 from the X coordinate acquired in step S23. If α is a positive value, the ball screw 12 is extended by α due to thermal displacement. On the other hand, if α is a negative value, it means that the ball screw 12 is contracted by α due to thermal displacement.

  Subsequently, the control section 300 moves the first X-axis slide section 45 to the processing standby position and then starts the processing of the work W (step S25). The processing standby position may be, for example, the same position as the detection standby position.

The processing of the work W in step S25 is performed as in the procedures (1) and (2) described above (about the processing of the work).
If the predetermined period has not elapsed (step S20; No), the first thermal displacement amount α acquired in step S24 is set as the correction amount as it is, and the first X-axis slide portion 45 is moved to a position in which the correction amount is taken into consideration. Let Specifically, if the preset target coordinate of the first X-axis slide unit 45 is X = A, the control unit 300 positions the corrected target coordinate (X = A + α) in which the correction amount α is added to the target coordinate. Then, by moving the first X-axis slide portion 45, the first processing mechanism M1 processes the work W.

  On the other hand, when the predetermined period has elapsed (step S20; Yes), the control unit 300 acquires the detected temperatures T1 to T8 at various locations based on the outputs of the temperature sensors St1 to St8 (step S26).

  Subsequently, the control unit 300 calculates the second thermal displacement amount β based on the acquired detected temperatures T1 to T8 and the correction formula (formula data) stored in the ROM in advance (step S27). For example, the correction formula is a formula represented by “β = a · T1 + b · T2 + c · T3 + d · T4 + e · T5 + f · T6 + g · T7 + h · T8 + i” where the predetermined coefficients are a to i. The coefficients a to i can be determined in advance by multiple regression analysis. The control unit 300 substitutes the acquired detected temperatures T1 to T8 into the correction formula to calculate the second thermal displacement amount β.

  Then, the control part 300 starts the process of the work W similarly to the above (step S25). However, when the predetermined period has elapsed (step S20; Yes), the second thermal displacement amount β acquired in step S27 is directly used as the correction amount, and the first X-axis slide portion 45 is placed at a position in which the correction amount is taken into consideration. To move. Specifically, if the preset target coordinate of the first X-axis slide unit 45 is X = A, the control unit 300 positions the corrected target coordinate (X = A + β) in which the correction amount β is added to the target coordinate. Then, by moving the first X-axis slide portion 45, the first processing mechanism M1 processes the work W.

  The control part 300 will return a process to step S20, if the process of the one workpiece W is complete | finished. The control unit 300 repeatedly executes the above processing until it receives a signal indicating an instruction to finish processing. It should be noted that the acquisition of the detected temperatures T1 to T8 and the calculation of the second thermal displacement amount β based on the acquired detected temperatures T1 to T8 may be executed in a predetermined cycle during the processing of one work W. Further, the thermal displacement process may be executed only when an arbitrary tool is indexed out of the plurality of tools Tf.

The correction of the thermal displacement in the Y-axis direction in the first processing mechanism M1 and the correction of the thermal displacement in the Z-axis direction in the second processing mechanism M2 can be similarly performed.
Briefly described, when correcting the thermal displacement in the Y-axis direction in the first machining mechanism M1, the control unit 300 moves the Y-axis moving unit 50 in the −Y direction in the reference position acquisition process to detect the detecting unit. It suffices to bring Sp2 into contact with the dog D2 and acquire the reference position of the Y coordinate. In the thermal displacement correction process, the first thermal displacement amount in the Y-axis direction is set as the correction amount within the predetermined period, and in the Y-axis direction calculated based on the temperature detected by the temperature sensor St after the predetermined period has elapsed. The second thermal displacement amount may be the correction amount.
Further, when correcting the thermal displacement in the Z-axis direction in the second machining mechanism M2, the control unit 300 moves the second Z-axis slide unit 84 in the + Z direction in the reference position acquisition process to move the detection unit Sp3 to the dog D3. To obtain the reference position of the Z coordinate. In the thermal displacement correction process, the first thermal displacement amount in the Z-axis direction is set as the correction amount within the predetermined period, and in the Z-axis direction calculated based on the temperature detected by the temperature sensor St after the predetermined period has elapsed. The second thermal displacement amount may be the correction amount.
The value of each coefficient of the correction formula used when obtaining the second thermal displacement amount can be determined in advance by multiple regression analysis for each axis of the thermal displacement correction target.

  The present invention is not limited to the above embodiments and drawings. Modifications (including deletion of constituent elements) can be appropriately added without changing the gist of the present invention.

  The example in which the dog D1 is the moving unit that moves in the X-axis direction together with the first X-axis slide unit 45 and the detection unit Sp1 is the immovable unit that does not move in the X-axis direction has been described above. It may be arranged so as to move in the X-axis direction relative to Sp1, and the relationship between the moving part and the immovable part may be reversed. That is, the detection unit Sp1 may be a moving unit that moves in the X-axis direction together with the first X-axis slide unit 45, and the dog D1 may be a stationary unit that does not move in the X-axis direction. The same applies to the relative movement relationship between the detection unit Sp2 and the dog D2 in the Y-axis direction and the relative movement relationship between the detection unit Sp3 and the dog D3 in the Z-axis direction.

  Further, when the control axes of the first machining mechanism M1 are X1, Y1, Z1 and the control axes of the second machining mechanism M2 are X2, Y2, Z2 in correspondence with the respective X, Y, Z axis directions, Then, an example in which the thermal displacement is corrected in each of the X1, Y1, and Z2 axes has been described, but the present invention is not limited to this. Of the X1, Y1, Z1, X2, Y2, and Z2 axes, which axis is the thermal displacement correction target axis is arbitrary.

  In the above, the example in which the plurality of temperature sensors St is eight of the temperature sensors St1 to St8 has been shown, but the installation location and the number of the plurality of temperature sensors St are arbitrary. Further, the temperature sensor St is not limited to the one using a thermistor, and may be, for example, a sensor that detects temperature by infrared radiation or a semiconductor temperature sensor.

  Further, in the above, an example in which the second thermal displacement amount is calculated based on a correction formula (data indicating a mathematical formula) stored in advance in the ROM has been described, but the second thermal displacement amount is calculated using the table data stored in advance in the ROM. The thermal displacement amount may be calculated. The table data can be configured by associating a detected temperature for each installation location of the temperature sensor St with a predetermined set value (for example, a value indicating a thermal displacement for each installation location). For example, the control unit 300 can obtain the second thermal displacement amount by referring to the table data, obtaining a plurality of set values corresponding to each detected temperature, and adding the obtained set values.

  Further, in the above, an example in which the first thermal displacement amount is used as it is as the correction amount for thermal displacement within a predetermined period from the start of machining of the workpiece W, and the second thermal displacement amount is used as it is as the correction amount for thermal displacement after the predetermined period has elapsed Although explained, it is not limited to this. For example, the correction amount of the thermal displacement may be obtained by multiplying the first thermal displacement amount acquired within the predetermined period by a coefficient, or the second thermal displacement amount acquired after the predetermined period has elapsed may be multiplied by the coefficient. May be a correction amount.

  Further, not only the first thermal displacement amount but also the second thermal displacement amount is calculated within a predetermined period from the start of processing of the work W, and the correction is performed based on the first thermal displacement amount and the second thermal displacement amount within the predetermined period. The amount may be calculated. In such a case, a simple average or a weighted average of the first thermal displacement amount and the second thermal displacement amount is obtained, and the obtained value can be used as the thermal displacement correction amount. Note that, within the predetermined period, as shown in FIG. 8, it is difficult to correct the thermal displacement based on only the output of the temperature sensor St. Therefore, when the correction amount is obtained using the weighted average, the output of the temperature sensor St is set. It is preferable to perform a calculation in which the first thermal displacement amount calculated based on the output of the detection unit Sp1 has a higher priority than the second thermal displacement amount calculated based on the calculation. Further, not only the second thermal displacement amount but also the first thermal displacement amount may be calculated after a predetermined period of time has elapsed, and the correction amount may be calculated based on the first thermal displacement amount and the second thermal displacement amount.

  Further, in the above, the example in which the detection unit Sp1 (the same applies to the detection units Sp2 and Sp3) is configured by a touch switch (an example of a contact sensor) has been described, but the present invention is not limited to this. The detection unit Sp1 may be a non-contact sensor. The non-contact sensor is, for example, an eddy current type distance measuring device, which measures the distance between itself and the target dog D1 (same for dogs D2 and D3) and supplies the measured value to the control unit 300. Is. Specifically, the control unit 300 causes a high-frequency current to flow in a coil included in the eddy current distance measuring device, and generates an eddy current on the surface of the dog D1 by an electromagnetic induction action, thereby changing according to the distance between the two. The impedance of the coil is acquired, and the distance is measured based on the acquired impedance value. In this case, the control unit 300 may acquire the coordinates at the time when the measurement value reaches the distance stored in advance in step S13 and step S23. Further, the contact sensor is not limited to the touch switch, and the non-contact sensor is not limited to the eddy current type distance measuring device. Both the contact sensor and the non-contact sensor may be arbitrarily selected from various known sensors.

  In the above description, the control unit 300 starts the work processing (step S25) and returns the processing to step S20 after processing one work W, but the present invention is not limited to this. The control unit 300 may return to the processing of step S20 after processing the plurality of works W or after a predetermined processing period has elapsed.

  Further, in the above step S20, the period to be compared with the predetermined period (hereinafter referred to as the target period T) has been described as the elapsed period from the time when the processing start instruction is received, but it is not limited to this. . For example, when the target period T is the sum of the machining period (operating period) of the machine tool 1 and the total of the operation stop period of the machine tool 1 is Tb, T = Ta−γ · Tb (γ is a coefficient ) May be a value that can be calculated. The coefficient γ is a value considering that the influence on the thermal deformation differs between the operation stop period and the processing period, and is arbitrary, but can be set to γ = 2, for example. That is, the control unit 300 can calculate the target period T by the above formula, and when executing step S20, it may determine whether the calculated target period T is longer than a predetermined period. . In addition, a plurality of predetermined periods are prepared or made variable, and the predetermined period can be changed according to the conditions (for example, when the thermal displacement correction process is executed for each machining of one work W and when the plurality of works W are processed). A configuration in which a predetermined period different from that in the case where the thermal displacement correction process is executed for each machining is settable) may be adopted.

  Further, in the above, the tool base 100 is assumed to be immovable with respect to the bed 2, but the present invention is not limited to this. The tool base 100 may be, for example, one that can move in the Y-axis direction and that can adjust the position of the tool Tr in the height direction with respect to the spindle 71.

  Further, although the machine tool 1 has been described as a multi-function lathe in the above, the present invention is not limited to this. A machine tool corresponding to only the first machining mechanism M1 or a machine tool corresponding to only the second machining mechanism M2 may be used. Further, the machine tool may be a milling machine, a drilling machine, or the like.

  Further, the operation program (program PG) for the CPU of the control unit 300 to execute the reference position acquisition process and the thermal displacement correction process has been described as being stored in the ROM of the control unit 300 in advance. The operation program and various data may be distributed and provided to the computer included in the machine tool 1 by a removable recording medium. Furthermore, the operation program and various data may be distributed by being downloaded from another device connected via a telecommunication network or the like.

  Further, the execution mode of each process is not limited to that executed by mounting a removable recording medium, but the operation program and various data downloaded via a telecommunication network etc. may be temporarily stored in a built-in storage device. It may be executable by means of, or may be executed directly by using the hardware resources of the other device side connected via a telecommunication network or the like. Furthermore, each process may be executed by exchanging various data with other devices via a telecommunication network or the like.

(1) The machine tool 1 described above moves in a predetermined axial direction (for example, the X-axis direction) with respect to the base (bed S) to process the work W gripped by the main spindle and the work W. Part for adjusting the relative position with respect to the tool in the axial direction (for example, the first X-axis sliding part 45), a moving part for moving in the axial direction together with the sliding part (for example, dog D1), and a stationary part that does not move in the axial direction. The control unit 300 includes a detection unit (detection mechanism 200) that detects contact with (for example, the detection unit Sp1) or that the detection unit Sp1 approaches a predetermined distance.
The control unit 300 functions as a calculation unit and a drive control unit. The calculating means acquires the axial position which is the axial position of the slide portion at the time of detection based on the detection by the detecting means, and acquires the detected temperature detected by the temperature sensor St provided at a predetermined position, A correction amount for correcting the thermal displacement in the axial direction is calculated based on at least one of the acquired axial position and the detected temperature. The drive control means moves the slide portion to a position in which the correction amount is added to the target position.
The calculation means calculates a first value (first thermal displacement amount) indicating the amount of thermal displacement based on the plurality of axial positions acquired at different detections, and estimates the amount of thermal displacement based on the detected temperature. A second value indicating the value (second thermal displacement amount) is calculated, the correction amount is calculated using the first value within a predetermined period from the start of machining the work, and the second value is calculated after the predetermined period has elapsed. The correction amount is calculated using this.

  According to the configuration of (1), it is possible to satisfactorily correct the thermal displacement from the start of processing the work W, and also possible to perform the thermal displacement correction in consideration of the thermal displacement generated in the configuration other than the slide portion. When the example of the slide section is the Y-axis slide section 51, the detection section Sp2 is an example of the moving section and the dog D2 is an example of the immovable section. When the second Z-axis slide section 84 is an example of the slide section, the detection section Sp3 is an example of the moving section and the dog D3 is an example of the immovable section.

(2) Further, the machine tool 1 has a tool portion (a Y-axis slide portion provided with the tool holding portion 52) having a hollow portion 51H through which the work W can be passed and a tool Tf whose tip faces the hollow portion 51H. 51) is further provided. Since the Y-axis moving section 50 is provided in the X-axis moving section 44, the tool section can move in the X-axis direction together with the first X-axis slide section 45 (slide section). In addition, the dog D1 and the detection unit Sp1 are located outside the hollow portion 51H in the X-axis direction.

  According to the configuration of (2), as described above, it is possible to prevent the chips generated during the processing of the work W from adhering to the dog D1 and the detection unit Sp1, and prevent the detection accuracy from decreasing. Further, since the X-axis direction is the radial direction of the work W, the processing accuracy in the radial direction of the work W can be improved.

(3) Further, the dog D1 and the detection unit Sp1 are at positions that do not overlap with the tool unit (Y-axis slide unit 51 provided with the tool holding unit 52) in the X-axis direction.

  According to the configuration of the above (3), as described above, it is possible to prevent the chips generated during the processing of the work W from adhering to the dog D1 and the detection unit Sp1, and prevent the detection accuracy from decreasing.

(4) Further, the detection unit Sp1 as a non-moving part is a contact sensor located outside the first X-axis slide part 45 in the X-axis direction.

  According to the configuration of (4) described above, as described above, the vibration applied to the detection unit Sp1 can be suppressed and the detection accuracy can be prevented from lowering.

(5) Further, the calculating means obtains the detected temperature from each of the plurality of temperature sensors St, and the plurality of temperature sensors is a ball screw for moving the first X-axis slide portion 45 (slide portion) in the X-axis direction. A temperature sensor St1 that detects the ambient temperature of 12 and a temperature sensor St2 to St8 that detects the ambient temperature of a configuration other than the ball screw 12 are included.

  With configuration (5) above, it is possible to perform thermal displacement correction in consideration of thermal displacement that occurs in another unit that does not move together with the slide portion.

(6) Further, the calculation means may calculate the correction amount not only by using the first thermal displacement amount (first value) but also by using the second thermal displacement amount (second value) within the predetermined period. .

(7) The program PG described above is for calculating a correction amount according to a predetermined thermal displacement of the machine tool 1 in the axial direction, and the control unit 300 (an example of a computer) has a detection unit. A process of acquiring an axial position which is an axial position of the slide portion at the time of detection based on the detection, and a process of acquiring a detected temperature detected by a temperature sensor provided at a predetermined location of the machine tool 1. A calculation process of calculating a correction amount for correcting the thermal displacement based on at least one of the acquired axial position and the detected temperature is executed. In the calculation process, a first value indicating the amount of thermal displacement is calculated based on a plurality of axial positions acquired at different detection times, and a second value indicating an estimated value of the amount of thermal displacement is calculated based on the detected temperature. Is calculated, and the correction amount is calculated using the first value within a predetermined period from the start of machining the work W, and the correction amount is calculated using the second value after the predetermined period has elapsed.

(8) The correction amount calculation method for calculating the correction amount according to the predetermined thermal displacement in the axial direction in the machine tool 1 described above is based on the detection by the detection means, and Based on at least one of the step of acquiring the axial position, which is the position, the step of acquiring the detected temperature detected by the temperature sensor provided at the predetermined location of the machine tool 1, and the acquired axial position and the detected temperature. And a calculation step of calculating a correction amount for correcting the thermal displacement. In the calculation step, a first value indicating the amount of thermal displacement is calculated based on the plurality of axial positions acquired at different detection times, and a second value indicating an estimated value of the thermal displacement is calculated based on the detected temperature. Is calculated, and the correction amount is calculated using the first value within a predetermined period from the start of machining the work W, and the correction amount is calculated using the second value after the predetermined period has elapsed.

  If the correction amount calculated by the configuration of (7) or (8) is used, the thermal displacement can be favorably corrected from the start of the machining of the workpiece W, and the thermal displacement considering the thermal displacement generated in the configuration other than the slide portion is also taken into consideration. Displacement correction can be performed.

  In the above description, in order to facilitate understanding of the present invention, description of known technical matters is appropriately omitted.

1 ... Machine tool 2 ... Bed M1 ... 1st processing mechanism 10 ... 1st X-axis sliding mechanism 20 ... Work holding part 30 ... 1st Z-axis sliding mechanism 40 ... Tool moving mechanism 41 ... Fixed stand 44 ... X-axis moving part 45 ... 1 X-axis slide part 50 ... Y-axis moving part M2 ... 2nd processing mechanism 60 ... Fixed stand 70 ... Work holding part 80 ... 2nd Z-axis slide mechanism 90 ... 2nd X-axis slide mechanism 100 ... Tool stand 200 ... Detection mechanism Sp1-Sp3 ... Detection unit D1 to D3 ... Dog St (St1 to St8) ... Temperature sensor 300 ... Control unit

Claims (8)

A slide unit that moves in a predetermined axial direction with respect to the base and that adjusts the relative position in the axial direction of the work held by the spindle and the tool for processing the work,
A detection unit that detects that the moving unit that moves in the axial direction together with the slide unit and the immovable unit that does not move in the axial direction come into contact with each other or that they approach each other by a predetermined distance,
The axial position, which is the axial position of the slide portion at the time of detection, is acquired based on the detection by the detection means, and the detected temperature detected by the temperature sensor provided at a predetermined location is acquired and acquired. Calculation means for calculating a correction amount for correcting the thermal displacement in the axial direction based on at least one of the axial position and the detected temperature;
Drive control means for moving the slide portion to a position in which the correction amount is added to the target position,
The calculation means is
A first value indicating the amount of thermal displacement is calculated based on a plurality of axial positions acquired at different detections, and a second value indicating an estimated value of the amount of thermal displacement is calculated based on the detected temperature. Then
The correction amount is calculated using the first value within a predetermined period from the start of machining the work, and the correction amount is calculated using the second value after the predetermined period has elapsed.
Machine Tools. Further comprising a tool portion having a hollow portion through which a work can be passed, and the tool having a tip facing the hollow portion,
The tool part is movable in the axial direction together with the slide part,
The axial direction is the radial direction of the work,
The moving portion and the immovable portion are located outside the hollow portion in the axial direction,
The machine tool according to claim 1. The moving part and the immovable part are in positions that do not overlap with the tool part in the axial direction,
The machine tool according to claim 2. The immovable portion is a contact sensor located outside the slide portion in the axial direction,
The detection means detects that the moving unit has contacted the contact sensor,
The machine tool according to any one of claims 1 to 3. The calculating means obtains the detected temperature from each of the plurality of temperature sensors,
The plurality of temperature sensors include a temperature sensor that detects an ambient temperature of a ball screw for moving the slide portion in the axial direction, and a temperature sensor that detects an ambient temperature of a configuration other than the ball screw.
The machine tool according to any one of claims 1 to 4. The calculation means calculates the correction amount by using not only the first value but also the second value within the predetermined period.
The machine tool according to claim 1. A slide unit that moves in a predetermined axial direction with respect to the base and that adjusts the relative position in the axial direction of the work held by the spindle and the tool for processing the work,
The shaft in a machine tool, comprising: a moving unit that moves in the axial direction together with the slide unit; and a detection unit that detects that a non-moving unit that does not move in the axial direction contacts or approaches a predetermined distance. A program for calculating the correction amount according to the thermal displacement in the direction,
On the computer,
A process of acquiring an axial position that is the axial position of the slide portion at the time of detection based on what the detection means detects;
A process of acquiring a detected temperature detected by a temperature sensor provided at a predetermined location of the machine tool,
And a calculation process of calculating a correction amount for correcting the thermal displacement based on at least one of the acquired axial position and the detected temperature,
In the calculation process,
A first value indicating the amount of thermal displacement is calculated based on a plurality of axial positions acquired at different detections, and a second value indicating an estimated value of the amount of thermal displacement is calculated based on the detected temperature. Then
The correction amount is calculated using the first value within a predetermined period from the start of machining the work, and the correction amount is calculated using the second value after the predetermined period has elapsed.
program. A slide unit that moves in a predetermined axial direction with respect to the base and that adjusts the relative position in the axial direction of the work held by the spindle and the tool for processing the work,
The shaft in a machine tool, comprising: a moving unit that moves in the axial direction together with the slide unit; and a detection unit that detects that a non-moving unit that does not move in the axial direction contacts or approaches a predetermined distance. A correction amount calculation method for calculating a correction amount according to a thermal displacement in a direction,
Acquiring the axial position which is the axial position of the slide portion at the time of detection based on the detection by the detection means,
Acquiring a detected temperature detected by a temperature sensor provided at a predetermined location of the machine tool,
A calculation step of calculating a correction amount for correcting the thermal displacement based on at least one of the acquired axial position and the detected temperature,
In the calculation step,
A first value indicating the amount of thermal displacement is calculated based on a plurality of axial positions acquired at different detections, and a second value indicating an estimated value of the amount of thermal displacement is calculated based on the detected temperature. Then
The correction amount is calculated using the first value within a predetermined period from the start of machining the work, and the correction amount is calculated using the second value after the predetermined period has elapsed.
Correction amount calculation method.

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