Estimation device, estimation method, and machine tool

Abstract

The present application relates to a control device (100) provided with: an arm (64) mounted to a drive section (62) capable of rotating a tray (76) around a rotation center axis, holding the tray (76) and changing a posture in an arm rotation range including a horizontal state and an upright state; a storage section (104) storing a first and second reference load when the arm (64) is individually rotated to a first and second arm position in the arm rotation range, and a horizontal direction distance between a tray central portion in the horizontal state and the rotation center axis, i.e., a reference distance (L); and an estimation section (106) acquiring a first and second load when the tray (76) changes the posture to the first and second arm position, and estimating a mass and a center of gravity position of the tray (76) based on at least the loads and the reference distance.

Description

Technical Field

[0001] This invention relates to an estimation device, estimation method, and machine tool. Background Technology

[0002] Patent document 1 discloses a method for detecting workpiece weight using an Automatic Pallet Changer (APC) on a machine tool (machining center). According to this method, the weight of the workpiece is calculated based on the load of the pallet lifting servo motor, and the acceleration and servo loop gain of the pallet lifting servo motor can be optimized based on the calculated weight. However, to improve the machining accuracy of the workpiece and the operating efficiency of the machine tool, it is desirable to detect not only the weight of the workpiece but also its center of gravity position.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-196105 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] In view of the above, the present invention aims to provide a device and method for estimating the mass and center of gravity of a pallet on which a workpiece is mounted with high precision without increasing the number of parts, in order to improve the machining accuracy of workpieces and the operating efficiency of machine tools.

[0008] Methods for solving problems

[0009] According to one aspect of the present invention, a device for estimating the mass and center of gravity of a pallet on which a workpiece is mounted is provided, comprising: a base; a drive unit mounted on the base and configured to rotate the pallet about a rotation center axis extending in a horizontal direction and to acquire a load; an arm rotatably mounted on the drive unit, holding the pallet having an upper surface for mounting a workpiece, and configured to change its posture within a range of arm rotation including a horizontal state in which the upper surface of the pallet is moved towards a horizontal plane and an upright state in which the upper surface of the pallet is moved towards a vertical plane; and a storage unit for storing the force exerted on the drive unit when the arm is rotated individually to a first arm position within the range of arm rotation. The first reference load, the second reference load acting on the drive unit when rotating to the second arm position within the arm rotation range different from the first arm position, and the horizontal distance, i.e., the reference distance, between the central portion of the pallet and the rotation center axis of the drive unit in a horizontal state; and the estimation unit, used to obtain the first load acting on the drive unit when changing the posture of the pallet held by the arm to the first arm position within the arm rotation range, and the second load acting on the drive unit when changing the posture to the second arm position within the arm rotation range, and to estimate the mass and center of gravity position of the pallet based at least on the reference distance, the first reference load, the second reference load, the first load, and the second load.

[0010] According to one aspect of the present invention, a method for estimating the mass and center of gravity position of a pallet on which a workpiece is mounted is provided, comprising: holding a pallet having a top surface for mounting a workpiece on an arm rotatably mounted to a drive unit configured to acquire a load; changing the posture within a range of arm rotation, including a horizontal state in which the upper surface of the pallet is moved to a horizontal plane and an upright state in which the upper surface of the pallet is moved to a vertical plane; acquiring a first reference load acting on the drive unit when the arm is rotated to a first arm position within the range of arm rotation; and acquiring a first reference load acting on the drive unit when the arm is rotated to a first arm position within the range of arm rotation. When the second arm is in the range of the second arm position, a second reference load acting on the drive unit is obtained; a first load acting on the drive unit is obtained when the pallet held by the arm is changed to the first arm position within the range of arm rotation; a second load acting on the drive unit is obtained when the pallet held by the arm is changed to the second arm position within the range of arm rotation; and, based on the horizontal distance between the central portion of the pallet in the horizontal state and the rotation center axis of the drive unit, i.e., the reference distance, and at least the first reference load, the second reference load, the first load and the second load, the mass and center of gravity position of the pallet are estimated.

[0011] According to one aspect of the present invention, a machine tool is provided, comprising: a spindle for mounting tools; a worktable for receiving a pallet fitted with a workpiece from an arm, capable of being mounted in an upright position; a housing integrally formed with a worktable support portion, a first actuator mounting portion, and a second actuator mounting portion; an actuator mounted on the first actuator mounting portion and the second actuator mounting portion, applying a force to the first actuator mounting portion and the second actuator mounting portion in a direction away from or near the housing, causing elastic deformation of the housing; an estimation device according to one aspect of the present invention; a calculation unit for calculating the adjustment force of the actuator acting on the first actuator mounting portion and the second actuator mounting portion based on the mass and center of gravity position of the pallet estimated by the estimation device; and a worktable position control device for operating the actuator such that the calculated adjustment force acts on the first actuator mounting portion and the second actuator mounting portion, causing elastic deformation of the housing and changing the position or orientation of the worktable support portion, thereby controlling the position of the worktable.

[0012] Invention Effects

[0013] One aspect of the present invention relates to an estimation device comprising a storage unit that stores: a first reference load acting on the drive unit when the arm is rotated to the first arm position; a second reference load acting on the drive unit when the arm is rotated to the second arm position; and a reference distance, i.e., the horizontal distance between the central portion of the pallet in a horizontal state and the rotation center axis of the drive unit. Furthermore, the estimation device comprises an estimation unit that acquires the first load acting on the drive unit when the pallet held by the arm is changed to the first arm position within the arm's rotation range, and the second load acting on the drive unit when the pallet is changed to the second arm position, and estimates the mass and center of gravity position of the pallet based at least on the reference distance, the first reference load, the second reference load, the first load, and the second load. Therefore, the mass and center of gravity position of the pallet can be estimated using the drive unit and the arm, enabling high-precision estimation of the mass and center of gravity position of a pallet with a workpiece mounted without increasing the number of parts. This facilitates easy confirmation and adjustment of the workpiece mounting position, and allows for control of the machine tool's operation, improving workpiece machining accuracy and machine tool operating efficiency.

[0014] According to one aspect of the present invention, the estimation method can obtain a first reference load acting on the drive unit when the arm is rotated to a first arm position within the arm's rotation range, and a second reference load acting on the drive unit when rotated to a second arm position. Furthermore, it can obtain the first load acting on the drive unit when the pallet held by the arm is repositioned to the first arm position within the arm's rotation range, and the second load acting on the drive unit when the pallet is repositioned to the second arm position. Moreover, it can estimate the mass and center of gravity of the pallet based on the horizontal distance (i.e., the reference distance) between the central portion of the pallet in a horizontal state and the rotation center axis of the drive unit, and at least the first reference load, the second reference load, the first load, and the second load. Therefore, the mass and center of gravity of the pallet can be estimated using the drive unit and the arm, enabling high-precision estimation of the mass and center of gravity of a pallet with a workpiece mounted without increasing the number of parts. This facilitates easy confirmation and adjustment of the workpiece's mounting position, and allows for control of the machine tool's operation, improving workpiece machining accuracy and machine tool operating efficiency.

[0015] According to one aspect of the present invention, a machine tool equipped with the estimation device of the same aspect can estimate the mass and center of gravity of a pallet using a drive unit and an arm, enabling high-precision estimation of the mass and center of gravity of a pallet with a workpiece mounted on it without increasing the number of parts. Furthermore, the machine tool includes an actuator and a calculation unit that calculates the adjustment force exerted by the actuator on the first and second actuator mounting portions based on the mass and center of gravity of the pallet estimated by the estimation device. Additionally, the machine tool includes a table position control device that operates the actuator by applying the calculated adjustment force to the first and second actuator mounting portions, causing elastic deformation of the housing and changing the position or orientation of the table support portion, thereby controlling the position of the table. This further facilitates easier confirmation and adjustment of the workpiece mounting position and improves the machine tool's operation, enhancing workpiece machining accuracy and machine tool operating efficiency. Attached Figure Description

[0016] Figure 1 A top view of a machine tool equipped with the presumed apparatus according to this embodiment.

[0017] Figure 2 This is a perspective view showing the estimation device involved in this embodiment.

[0018] Figure 3 This diagram shows the claws engaging with the pin at the tray engagement position, viewed from the length of the arm.

[0019] Figure 4 A block diagram illustrating the machine tool involved in this embodiment.

[0020] Figure 5 (a) shows a side view of the arm when the first load is acquired. Figure 5 (b) shows a side view of the arm when the first reference load is obtained.

[0021] Figure 6 (a) shows a side view of the arm when the second load is acquired. Figure 6 (b) shows a side view of the arm when the second reference load is obtained.

[0022] Figure 7A This is a side view of the arm when the load is being acquired at a position where the arm is tilted θ1 degrees relative to the horizontal plane.

[0023] Figure 7B This is a side view of the arm when the load is being acquired at a position where the arm is tilted θ2 degrees relative to the horizontal plane.

[0024] 【 Figures 8a-8b Figure 8a shows a side view of the arm when the center of gravity is not aligned with the center of the pallet to obtain the first load, and Figure 8b shows a side view of the arm when obtaining the second load.

[0025] 【 Figures 8c-8d Figure 8c shows a front view of the worktable when the first worktable load is obtained, and Figure 8b shows a front view of the worktable when the second worktable load is obtained.

[0026] Figure 9 A flowchart illustrating the position control of the workbench.

[0027] Figure 10 A side view showing a pallet being moved in from the outside of the machine tool.

[0028] Figure 11 This is a side view of the arm after it has been rotated to the engaged position and positioned relative to the tray.

[0029] Figure 12 A side view of the tray in which the pawls engage with the pins to move to the tray engagement position.

[0030] Figure 13 A side view showing the tray changing its posture to an upright position.

[0031] Figure 14 This shows a side view of the tray held in the APC arm.

[0032] Figure 15 A side view of a tray in an upright position, showing the gripper moving to the tray engagement / disengagement position.

[0033] Figure 16 A side view showing the arm rotated to the standby position.

[0034] Figure 17This is a side view of the second pallet replaced by the APC arm.

[0035] Figure 18 This is a side view of the C-axis rotary table after the replacement tray has been installed.

[0036] Figure 19 This is a side view of the APC arm handing over the pallet to the C-axis rotary table.

[0037] Figure 20 A side view showing the pallet and workpiece tilted due to their own weight.

[0038] Figure 21 This is a side view of a C-axis rotary table that actuates the actuator for tilt correction.

[0039] Figure 22 This is a side view of the C-axis rotary table that has been rotated toward the spindle for machining. Detailed Implementation

[0040] Hereinafter, a machine tool equipped with the presumed device according to the embodiment will be described with reference to the accompanying drawings. The same or corresponding elements will be labeled with the same reference numerals, and repeated descriptions will be omitted. For ease of understanding, the scaling of the drawings may sometimes be changed during the description.

[0041] exist Figure 1 The diagram shows a schematic top view of a machine tool 10 equipped with a pallet orientation changing device 42, which is the presumed device according to this embodiment. The machine tool 10 is covered by a protective cover 16 to prevent the scattering of chips and the like generated during machining. Furthermore, the interior of the protective cover 16 is equipped with a rotation axis R2 (see reference 16) that is parallel to the vertical direction. Figure 2 A rotating door 46, configured to rotate (able to return), divides the processing chamber 12 and the preparation chamber 14. Furthermore, on the protective cover 16, the operator's WK (refer to...) is... Figure 4 The processing room 12 and the preparation room 14 are respectively equipped with an operator door 12a and a preparation room door 14a, which allow external access to the interior of the processing room 12 and the preparation room 14.

[0042] The machining chamber 12 is equipped with workpieces W1 and W2 (see reference) for machining the workpieces. Figure 10 and Figure 17 The machine tool 10 includes a spindle 26, a C-axis rotary table 36 serving as a worktable, and other similar equipment. On the bed 18, located on the ground of a factory or similar facility where the machine tool 10 is installed, a pair of X-axis linear guideways 30 extending in the left-right direction (X-axis direction) are mounted. A column 22, capable of reciprocating along the X-axis linear guideways 30, is erected on each X-axis linear guideway 30. Furthermore, the machine tool 10 has a vertically aligned (Y-axis direction, relative to...) section in front of the column 22. Figure 1A pair of Y-axis linear guides (not shown) extending in the direction perpendicular to the paper surface are provided, and a saddle 24 capable of reciprocating along the Y-axis linear guides is arranged on the Y-axis linear guides. A spindle 26 configured to rotate about a central axis in the horizontal direction is arranged in front of the saddle 24. Furthermore, a tool 28 for machining workpieces W1 and W2 is detachably mounted in front of the spindle 26 (on the preparation chamber 14 side). The machine tool 10 is equipped with an NC device (not shown) electrically connected to the spindle 26 for controlling the machining process, configured to control the machining of workpieces W1 and W2 using the tool 28.

[0043] On the front side of the spindle 26 of the machine tool 10, on the upper surface of the bed 18, there is a pair of Z-axis linear guideways 38 extending in the front-rear direction, i.e., the Z-axis direction. A Z-axis worktable 32 capable of reciprocating along the Z-axis linear guideways 38 is arranged on the Z-axis linear guideways 38. Furthermore, on the Z-axis worktable 32, a B-axis rotary worktable 34 configured to rotate about a rotation axis (about the B-axis) parallel to the vertical direction is arranged. Furthermore, on the B-axis rotary worktable 34, a C-axis rotary worktable 36 serving as a worktable is arranged, which is configured to allow the upper surface 76a (refer to the reference) of the mounted tray 76 (first tray) to be rotated. Figure 2 The C-axis rotary table 36 is configured to allow the mounted workpieces W1, W2, and pallet 76 to rotate about a horizontal central axis (about the C-axis). Thus, the Z-axis table 32, B-axis rotary table 34, and C-axis rotary table 36 enable the positioning of workpieces W1, W2, and tool 28. Furthermore, the machine tool 10 includes an X-axis feed device for driving the column 22 along the X-axis linear guide 30, a Y-axis feed device for driving the saddle 24 along the Y-axis linear guide 38, and a Z-axis feed device for driving the Z-axis table 32 along the Z-axis linear guide 38 (all figures omitted).

[0044] like Figure 4 and Figure 18As shown, the C-axis rotary table 36 includes a table 36d, a table support 36c supporting the rotation axis of the table 36d, and a housing 36e integrally formed with a first actuator mounting portion 36a and a second actuator mounting portion 36b disposed on the rear side of the C-axis rotary table 36. The rotation center axis CC of the table 36d of the C-axis rotary table 36 (see Figure 8c) extends horizontally. The first actuator mounting portion 36a extends horizontally on the lower side of the C-axis rotary table 36, and the second actuator mounting portion 36b extends horizontally on the upper side of the C-axis rotary table 36. The vertical spacing between the first actuator mounting portion 36a and the rotation center axis CC and the vertical spacing between the second actuator mounting portion 36b and the rotation center axis CC are configured to be the same. Furthermore, on the back side of the C-axis rotary table 36, an actuator 35 extending vertically in a manner orthogonal to the rotation center axis CC is mounted via a first actuator mounting portion 36a and a second actuator mounting portion 36b. The actuator 35 is a pull-in type hydraulic cylinder configured to apply force to the first actuator mounting portion 36a and the second actuator mounting portion 36b in a direction away from or near the housing 36e, causing the housing 36e to elastically deform. Furthermore, the table 36d is configured to rotate via a built-in servo motor 36f, which has an encoder 36g configured to detect rotational position and is electrically connected to a servo amplifier 36h configured to supply power to the servo motor 36f and detect rotational position from the encoder 36g. While the actuator 35 is described here as being integrally formed, it is not limited to this; for example, the actuator may also be formed from multiple units divided into a first actuator mounting portion side and a second actuator mounting portion side. The workbench support 36c can be composed of bearings, etc.

[0045] like Figure 1 As shown, a preparation station 40 is provided in the preparation chamber 14 for performing the following preparations: mounting (assembling) the workpiece W1 before processing onto the pallet 76, and unloading the workpiece W2 after processing. The preparation station 40 is equipped with a pallet orientation changing device 42 for changing the orientation of the workpieces W1 and W2 mounted on the pallet 76. Furthermore, the preparation station 40 is equipped with a medium supply unit 80 for supplying a medium containing oil, air, or cutting fluid to the pallet 76 and any one of the workpieces W1 and W2 mounted on the pallet 76 and / or the fixture. The medium supply unit 80 is configured to be installed via the lower part 76b of the pallet 76 (see reference 76b). Figure 2 The connector (illustration omitted) supplies the medium.

[0046] A rotary door 46, separating the processing chamber 12 and the preparation chamber 14, extends vertically between the side walls of the protective cover 16 and is mounted on a rotary door retaining portion 48 disposed below the side wall of the protective cover 16. Specifically, it is mounted in a state where the fitting portions (not shown) formed on both the rotary door 46 and the rotary door retaining portion 48 are engaged. Furthermore, the width direction of the rotary door 46 is the left-right direction, i.e., the X-axis direction, as viewed from the front of the machine. On the lower side of the rotary door 46, a tray exchange device 44 is disposed, which is configured to rotate around a rotary axis R1 parallel to the vertical direction (Y-axis direction) independently of or in conjunction with the rotary door 46. The pallet exchange device 44, for transferring workpiece W1 before processing and workpiece W2 after processing between the preparation chamber 14 and the processing chamber 12, includes: an APC arm 50 as a rotary arm, which is configured to rotate about a rotary axis R1 parallel to the vertical direction (Y-axis direction); and an APC arm drive mechanism 56 as a rotary drive unit for rotating the APC arm 50. Furthermore, the APC arm 50 is configured to be able to rotate along the vertical direction (Y-axis direction) via the APC arm drive mechanism 56. Figure 2 The APC arm drive mechanism 56 has an actuator (not shown) such as a hydraulic cylinder, a pneumatic cylinder, or a servo motor capable of fine motion setting and adjustment, which causes the APC arm 50 to rotate and move up and down. Furthermore, the actuator is configured to be controlled by a control device 100 (see reference 100) located on the machine tool 10. Figure 4 Control. Furthermore, although it is described that the rotating door retainer 48 is disposed on the lower side of the side wall of the protective cover 16, it is not limited thereto; the rotating door retainer can also be directly disposed on the bed or the ground. Moreover, as long as the rotating door retainer can replace the APC arm in restricting the rotation direction and gravity direction of the rotating door when the APC arm is lowered and not engaged with the rotating door, the rotating door can also be held in a manner other than the engaging part.

[0047] When workpieces W1 and W2 are not being exchanged, the APC arm 50 is positioned and stored in a storage position, with its length direction along the width direction of the rotary gate 46, i.e., the X-axis direction. Furthermore, a chip shield 52 is formed on the lower side of the rotary gate 46. This chip shield 52 has an inclined surface that extends towards the preparation station 40 and the machining chamber 12 (front and rear sides in the Z-axis direction) towards its lower side (vertical lower side). The chip shield 52 is configured to cover the APC arm 50, which engages with the rotary gate 46, from above, preventing or suppressing chips and other debris generated during machining in the machining chamber 12 from adhering to the APC arm 50.

[0048] like Figure 2As shown, the APC arm 50 has a first tray holding portion 82 and a second tray holding portion 84 at both ends in the longitudinal direction for holding the tray 76. The first tray holding portion 82 and the second tray holding portion 84 have columnar members at both ends in the width direction of the APC arm 50, and are concave in shape when viewed from the longitudinal direction of the APC arm 50. A holding member 76f is installed on the side of the tray 76 opposite to the APC arm 50, i.e., the abutting side 76d. The holding member 76f is formed into a plate shape of a size that can be embedded into the concave portions of the first tray holding portion 82 and the second tray holding portion 84. Therefore, when the tray 76 is in an upright state, the holding member 76f is embedded into the concave portions of the first tray holding portion 82 and the second tray holding portion 84, and the top surfaces of the columnar members at both ends of the first tray holding portion 82 and the second tray holding portion 84 abut against the abutting side 76d of the tray 76. Thus, the APC arm 50 can support the pallet 76 and maintain the pallet 76 in an upright position, as well as the fixture 96 and workpieces W1 and W2 mounted on it (see reference). Figure 10 and Figure 17 ).

[0049] Furthermore, the first tray holding portion 82 and the second tray holding portion 84 of the APC arm 50 are described here as components that support the tray 76 by embedding the holding member 76f into the concave portion and having the upper surface of the columnar members at both ends abut against the abutting side 76d of the tray 76, but are not limited thereto. For example, the holding portion of the APC arm may also be configured by a mechanism that clamps the upper and lower surfaces of the tray.

[0050] In addition, such as Figure 1As shown, the APC arm 50 and the rotary door 46 can be engaged by the engaging mechanism 54. The engaging mechanism 54 is configured to include an engaging pin 54a on the APC arm 50 side and a guide hole 46a on the rotary door 46 side. The engaging pin 54a is formed extending upwards from the upper side of the APC arm 50. Therefore, the engaging pin 54a is configured to move up and down with the up and down movement of the APC arm 50. Furthermore, the guide hole 46a is formed at the bottom of the rotary door 46 to engage with the inserted engaging pin 54a. Here, two engaging pins 54a are arranged at 180° intervals around the rotary axis RA2 of the APC arm 50, and four guide holes 46a are formed at 90° intervals around the rotary axis RA2 of the APC arm 50, corresponding to the engaging pins 54a. In addition, at least one pair of engaging pins 54a and guide holes 46a is required. The engaging mechanism 54 is configured such that the engaging pin 54a and the guide hole 46a can engage or disengage, thereby enabling the APC arm 50 to engage with the revolving door 46. Therefore, when the APC arm 50 is engaged with the revolving door 46, the APC arm 50 and the revolving door 46 can rotate together. Furthermore, when the engagement between the APC arm 50 and the revolving door 46 is disengaged, the APC arm 50 can rotate independently to facilitate the transfer of trays 76 and 94, or to retract the untransferred APC arm 50 to its storage position. While this description focuses on the case where the APC arm 50 has the engaging pin 54a and the guide hole 46a is formed at the bottom of the revolving door 46, the description is not limited to this. For example, the revolving door may also have an engaging pin extending from the bottom, and the APC arm may also have a guide hole. Furthermore, it can be not only a combination of the engaging pin 54a and the guide hole 46a, but also configured to engage / disengage the claws and other parts disposed on both the APC arm and the rotary door. Moreover, the engaging pin is not limited to a rod or column shape; for example, it can be configured to use a drive mechanism disposed on the engaging mechanism and be capable of vertical movement.

[0051] The pallet exchange device 44 operates as follows. In the machine tool 10, when the exchange of pallets 76 begins, the engaging mechanism 54 disengages the rotary door 46 from the APC arm 50, and the APC arm drive mechanism 56 lowers the APC arm 50. At this time, the rotary door 46 is released from engagement with the APC arm 50 due to the disengagement of the engaging pin 54a of the engaging mechanism 54 from the guide hole 46a, and is thus engaged with the rotary door retaining portion 48 and placed thereon. When the APC arm 50 lowers, the APC arm drive mechanism 56 rotates the APC arm 50 90 degrees (or 270 degrees). Therefore, the first pallet retaining portion 82 and the second pallet retaining portion 84 of the APC arm 50 move along the rotation trajectory TR1 (see reference...). Figure 1 The APC arm 50 moves towards the C-axis rotary table 36 and the pallet posture changing device 42, so that the length direction of the APC arm 50 is along the Z-axis.

[0052] When the first pallet holding part 82 and the second pallet holding part 84 move toward the C-axis rotary table 36 and the pallet posture changing device 42, the APC arm drive mechanism 56 raises the APC arm 50. As the APC arm 50 rises, the engaging pin 54a of the engaging mechanism 54 inserts into the guide hole 46a and engages. As a result, the rotary door 46 engages with the APC arm 50, replacing the rotary door holding part 48, and thus the rotary door 46 is loaded onto the APC arm 50.

[0053] When the APC arm 50 is loaded with the rotating door 46, the APC arm drive mechanism 56 raises both the rotating door 46 and the APC arm 50. This allows the tray 76 to be held in place by inserting the holding member 76f of the tray 76 into the concave portions of the first tray holding part 82 and the second tray holding part 84, and by having the columnar members at both ends abut against the contact side 76d of the tray 76. Here, the tray 76 is transferred from the C-axis rotary table 36 and the tray posture changing device 42 to the APC arm 50. After transferring the tray 76 to the APC arm 50, the C-axis rotary table 36 and the tray posture changing device 42 retract to a standby position that does not interfere with the rotating APC arm 50 and the rotating door 46. Then, the APC arm 50 rotates them 180 degrees as a whole. This allows the tray 76 held by the APC arm 50 to be changed between the processing chamber 12 side and the preparation chamber 14 side. When pallet 76 is replaced, the arm 64 of the C-axis rotary table 36 and / or pallet attitude changing device 42 moves from the standby position to the pallet handover position, holding the replaced pallets 76 and 94. Then, the APC arm drive mechanism 56 lowers the rotating door 46 and the APC arm 50, which is holding pallet 76, so that only the rotating door 46 mounted on the APC arm 50 is engaged with the rotating door holding part 48. Furthermore, the engaging pin 54a of the engaging mechanism 54 is pulled out from the guide hole 46a, and the engagement is released. After lowering the APC arm 50, the APC arm drive mechanism 56 rotates 90 degrees, moving the first pallet holding part 82 and the second pallet holding part 84 to the lower side of the rotating door 46.

[0054] When the first tray holding part 82 and the second tray holding part 84 move towards the lower side of the rotary door 46, the APC arm drive mechanism 56 raises the APC arm 50, and the rotary door 46 is loaded onto the APC arm 50 in place of the rotary door holding part 48. Then, the engaging pin 54a of the engaging mechanism 54 inserts into the guide hole 46a to engage. Thus, the APC arm 50 is stored in the storage position below the rotary door 46.

[0055] like Figure 2 As shown, in the preparation station 40, there is a spacer for transferring and assembling the prepared workpiece W1 (before processing) and the processed workpiece W2 (after processing) between the preparation station 40 and the APC arm 50. Figure 10 and Figure 17 The pallet 76 has a pallet orientation changing device 42. The pallet 76 is configured to have a fixture 96 for assembling workpieces W1, W2 and a clamp 96 (see reference). Figure 10 The tray 76 has a plate-like upper part 76a and a lower part 76b. Furthermore, the tray 76 has: two engaging sides 76e, which are in contact with the upper part 76a and the lower part 76b and are located on the outer side of the tray 76 in the X-axis direction; an abutting side 76d, which is located between the two engaging sides 76e and on the rear side of the tray 76 in the Z-axis direction, opposite to the APC arm 50; and a front side 76c, which is located on the front side of the tray 76 in the Z-axis direction and opposite to the preparation chamber door 14a. Furthermore, the two engaging sides 76e have pins 78, which are integrally formed with the tray 76 and extend outward, i.e., outward in the X-axis direction. Here, on each engaging side 76e, two cylindrical pins 78 extending along the surface direction of the engaging side 76e are formed. The two pins 78 are spaced apart at each end of the long side (Z-axis direction) of the engaging side 76e. Alternatively, one pin may be formed on each engaging side, or it may be formed in a shape other than a cylinder, such as a prism or a triangular prism.

[0056] The operator WK, who assembles the workpiece W1 and the fixture 96 in the preparation station 40 of the preparation chamber 14, places the pallet 76 on the media supply unit 80 with the top 76a of the pallet 76 facing the horizontal plane. In order to transfer the pallet 76 between the preparation station 40 and the C-axis rotary table 36, which is mounted in an upright position, the pallet attitude changing device 42 is configured to hold the pallet 76 and change its attitude to a state that includes both a horizontal and an upright position. Specifically, the pallet posture changing device 42 includes: a base 60 disposed along the X-axis in front of the rotary door 46 and the APC arm 50 in the Z-axis direction; a drive unit 62 mounted on the base 60, configured to rotate a rotation axis extending along the X-axis (horizontal direction) about a rotation center axis RA1 (R1 direction); and a pair of arms 64 rotatably mounted on the drive unit 62, extending parallel to the two engaging sides 76e when facing them, capable of holding the pallet 76. Figure 10 As shown, the base 60 extends forward in the Z-axis direction (towards the preparation chamber door 14a) from the outer periphery of the APC arm drive mechanism 56, which is located at the rotation center of the APC arm 50. Therefore, the base 60 can be positioned inside the rotation trajectory TR1 of the APC arm 50 when viewed from above, and when the APC arm 50 rotates while holding the tray 76 with workpieces W1 and W2 mounted at its end, it can prevent chips from falling directly onto the base 60.

[0057] The drive unit 62 is equipped with a hydraulic cylinder, a pneumatic cylinder, or a servo motor 62a capable of fine motion setting and adjustment (see reference). Figure 4 The servo motor 62a is used to rotate the rotating shaft. The servo motor 62a has an encoder 62b configured to detect the rotational position and is electrically connected to a servo amplifier 62c configured to supply power to the servo motor 62a and obtain the rotational position from the encoder 62b. Furthermore, the servo motor 62a is configured to be controllable by a control device 100 (see reference 100) located on the machine tool 10. Figure 4 The pallet posture changing device 42, as described later, is capable of rotating the arm 64 not only between an upright position and a horizontal position, but also of rotating the arm 64 from an upright position to a retracted position beyond the engaging position in the horizontal position, and is configured to be stationary. Furthermore, the pallet posture changing device 42 is configured to be stationary even in an intermediate position such as a standby position between an upright position and an engaging position.

[0058] Furthermore, the following description focuses on the case where the tray 76 is square in top view, with its two parallel engaging sides 76e held by a pair of parallel arms 64, but is not limited to this. For example, the tray may also include cases where the corners are chamfered, or where the tray is octagonal or circular in top view, and other than a square shape. Moreover, even if the two engaging sides are not parallel due to the tray being a shape other than a square, the pair of arms may extend in a V-shape in top view, for example, parallel to the two engaging sides. Additionally, if the tray is circular, the arms may be curved and designed to follow the shape of the tray.

[0059] like Figure 2As shown, the arm 64 has: an arm base end portion 66 connected to the rotation axis of the drive unit 62; and an arm engaging portion 68 extending linearly from the outer portion of the arm base end portion 66 in the X-axis direction, so as to be opposite to the engaging side 76e. On the inner side of the arm base end portion 66, which serves as the base 60 side of the arm 64, a receiving portion 74 is formed, positioned opposite to the abutting side 76d when the pallet 76 is held by the arm 64. When viewed from the side (outer X-axis direction) of the machine tool 10 in a horizontal state, the receiving portion 74 is L-shaped or inverted L-shaped, having a planar first pallet receiving surface 74a extending vertically relative to the arm 64, and a planar second pallet receiving surface 74b extending along the length direction of the arm 64. The dimensions are set such that the abutting side 76d abuts against the first pallet receiving surface 74a, and the lower surface 76b abuts against the second pallet receiving surface 74b. Furthermore, the dimensions of the first and second pallet-receiving surfaces do not need to be strictly defined; they only need to be formed to a degree that allows them to abut against the pallet and reliably bear its own weight. Therefore, the first and second pallet-receiving surfaces are not limited to flat surfaces; for example, they can also be formed into curved or pyramidal shapes, thereby supporting the pallet in a point-contact or line-contact manner.

[0060] Each arm 64 has two sliding portions 70 at both ends of the arm engaging portion 68 along its length, i.e., at both ends along the Z-axis. These portions are configured to slide along the length of the arm engaging portion 68. Furthermore, each of the two sliding portions 70 is equipped with a pawl 72 for engaging with the tray 76. The spacing between the two pawls 72 corresponds to the spacing between the two pins 78. A rod disposed within the arm engaging portion 68 is integrally connected to each of the two sliding portions 70. This rod is connected to an actuator such as a hydraulic cylinder, a pneumatic cylinder, or a servo motor capable of fine motion setting and adjustment (all figures omitted). Therefore, the sliding portions 70 and pawls 72 can move in the same direction between the tray engaging position and the tray disengaged position based on the movement of the rod by the actuator. Here, the tray engaging position is configured to be closer to the arm base end 66 than the tray disengaged position. Furthermore, the actuators that move the sliding portions 70 and pawls 72 are configured to be controlled by a control device 100 disposed on the machine tool 10 (see reference). Figure 4 To control it. For example... Figure 3As shown, the claw 72 has: a central portion 72c facing the engaging side 76e when the arm engaging portion 68 is moved to the side of the tray 76 to hold the tray 76; an upper side limiting portion 72a formed on the upper side (upper side 76a side) of the central portion 72c; and a lower side limiting portion 72b formed on the lower side (lower side 76b side) of the central portion 72c. Therefore, a groove 72d is formed by the central portion 72c, the upper side limiting portion 72a, and the lower side limiting portion 72b. When the claw 72 is viewed from the length direction of the arm 64, the groove 72d is formed as a concave shape facing the tray 76 side. The groove 72d is formed such that its depth direction coincides with the extending direction of the pin 78. Therefore, by moving the arm engaging portion 68 to the side of the engaging side 76e of the tray 76, and moving it from a position where the pawl 72 and the pin 78 are not facing each other along the X-axis (tray engagement release position) to a position where the pawl 72 and the pin 78 are facing each other along the X-axis (tray engagement position) (sliding along the XF1 direction), the pawl 72 can be engaged with the tray 76. Thus, the arm 64 can stably hold the tray 76. Furthermore, since the concave groove 72d is open relative to the outside of the pawl 72, it is possible to prevent or suppress the trapping of chips generated during machining between the pawl 72 and the pin 78.

[0061] In addition, the case where the claw 72 is concave towards the tray 76 when viewed from the length direction of the arm 64 has been described here, but it is not limited to this. It can be any shape that can engage with the pin. For example, the claw can also be formed into a V-shape or other shapes that are open towards the pin when viewed from the length direction of the arm.

[0062] Furthermore, on the inner side of the arm engaging portion 68 in the width direction opposite to the engaging side 76e, i.e., in the X-axis direction, an arm protrusion 86 extending toward the engaging side 76e is formed (see reference). Figure 10 Furthermore, a tray groove 88 is formed on the engaging side 76e, recessed inwards towards the tray 76, configured to allow the arm protrusion 86 to be inserted. Thus, the arm 64 can hold the tray 76 using both the claw 72 and the arm protrusion 86, thereby stably holding the tray 76.

[0063] Furthermore, here, the claw 72 of the arm engaging portion 68 is configured to be able to move along the length direction of the arm engaging portion 68, i.e., the Z-axis direction ( Figure 3 The sliding of the pawl (in the XF1 direction) between the tray engagement / disengagement position and the tray engagement position has been described, but it is not limited to this. The pawl can also be configured along the X-axis direction, that is, in the direction opposite to the tray. Figure 3 The claw slides in the XF2 direction to hold the tray. In this configuration, since the claw does not displace in the length direction of the arm, space can be saved in the length direction, allowing for a compact arm configuration.

[0064] exist Figure 4 The diagram shows a block diagram of a machine tool 10. The machine tool 10 includes a control unit 100 with an NC (NC) device 102 for machining control. The NC device 102 is electrically connected to a servo amplifier 62c for a drive unit 62, configured to send commands to the servo amplifier 62c regarding the rotational position of the arm 64, and to acquire, via the servo amplifier 62c, the current value or torque generated in the servo motor 62a and the rotational position of the arm 64 detected by the encoder 62b. Therefore, the machine tool 10 can acquire (calculate) the load (load) acting on the arm 64 holding the tray 76 as the torque generated in the servo motor 62a, based on the current value generated in the servo motor 62a. Furthermore, while the drive unit 62 is described here as acquiring the load from both arms 64 simultaneously, it is not limited to this configuration. For example, a first drive unit and a second drive unit corresponding to each of the two arms may be configured, and the load may be acquired by summing the loads (torques) acquired by them.

[0065] Furthermore, the NC device 102 is electrically connected to a servo amplifier 36h for the C-axis rotary table 36, configured to send a command for the rotational position of the table 36d to the servo amplifier 36h, and to acquire the current value or torque generated in the servo motor 36f and the rotational position of the table 36d detected by the encoder 36g via the servo amplifier 36h. Therefore, the machine tool 10 can acquire (calculate) the load (load) acting on the table 36d holding the pallet 76 as the torque generated in the servo motor 36f based on the current value generated in the servo motor 36f.

[0066] The control device 100 also includes a storage unit 104, a estimation unit 106, and a calculation unit 108. The storage unit 104 is configured to store the load of the drive unit 62 and the load of the C-axis rotary table 36 acquired by the NC device 102. Furthermore, as described later, the storage unit 104 is configured to pre-store a first reference load TB1 and a second reference load TB2. When the arm 64 rotates to the first arm position within the arm's rotation range (including both horizontal and vertical states) while the arm 64 is alone (i.e., without any load other than its own load), the first reference load TB1 acts on the drive unit 62 (see reference 108). Figure 5 b) When the second arm rotates to a position within the arm's rotation range different from the first arm position, the second reference load TB2 acts on the drive unit 62 (see reference). Figure 6 b). In addition, the horizontal distance L between the central portion of the tray 76 in the pre-stored horizontal state and the rotation center axis RA1 of the drive unit 62 is the reference distance.

[0067] The estimation unit 106 is configured to obtain the first load T1 acting on the drive unit 62 when the tray 76 held by the arm 64 changes its posture to the first arm position within the arm's rotation range (see reference). Figure 5 a) and the second load T2 acting on the drive unit 62 when the posture is changed to the second arm position within the arm rotation range (see reference). Figure 6 a) Based on the reference distance L, the first reference load TB1, and the first load T1, the mass M of the pallet 76 on which the workpiece W1 is mounted is estimated. Furthermore, the position H of the center of gravity GW1 of the pallet 76 on which the workpiece W1 is mounted is estimated based on the estimated mass of the pallet 76, the second reference load TB2, and the second load T2.

[0068] pass Figure 5 a and Figure 5 b explains the method for estimating the mass M of pallet 76. First, as... Figure 5 As shown in diagram a, the horizontal distance L between the center portion of the pallet (which also corresponds to the position of the center of gravity GW1) and the rotation center axis RA1 of the drive unit 62 when the pallet 76 is in a horizontal state, i.e., when the arm 64 is in the engaged position, is measured in advance or obtained from the design information, and is stored in the storage unit 104. Furthermore, as Figure 5 As shown in b, the first reference load TB1 is obtained when the arm 64 is in the engaged position, which is the first arm position, in a state where there is no load other than the load on the arm 64 itself, and is stored in the storage unit 104. Specifically, using a pre-defined conversion formula between current and torque, the first reference load TB1, which is the torque acting on the drive unit 62, is obtained based on the current value generated in the servo motor 62a. Next, as... Figure 5 As shown in figure a, the current value of the servo motor 62a is obtained when the arm 64 of the holding tray 76 is in the engaged position, and the first load T1, which is the torque acting on the drive unit 62, is obtained by the same method as the first reference load TB1. The relationship between the reference distance L, the first reference load TB1, the first load T1, and the mass M can be expressed as follows.

[0069] T1-TB1=MgL (1)

[0070] Where g represents gravitational acceleration.

[0071] Therefore, by transforming equation (1) into

[0072] M = (T1 - TB1) / gL (2)

[0073] It is possible to estimate (calculate) the mass M.

[0074] Next, through Figure 6 a and Figure 6b. The position of the center of gravity GW1 of the pallet 76, and here the method for estimating the distance H of the center of gravity position, will be explained. The distance H of the center of gravity position is defined as the horizontal distance between the center of gravity GW1 and the rotation center axis RA1 of the drive unit 62 when the arm 64 of the pallet 76 is in an upright position. First, as Figure 6 As shown in b, when arm 64 is alone, i.e., not holding tray 76 and in an upright position as the second arm position, a second reference load TB2, which serves as the torque acting on drive unit 62, is obtained based on the current value generated in servo motor 62a and stored in storage unit 104. Specifically, using a pre-defined conversion formula between current value and torque, the second reference load TB2, which serves as the torque acting on drive unit 62, is obtained based on the current value generated in servo motor 62a. Next, as... Figure 6 As shown in Figure a, the current value of the servo motor 62a is obtained when the arm 64 of the tray 76 is in an upright position, and the second load T2, which is the torque acting on the drive unit 62, is obtained by the same method as the second reference load TB2. The horizontal distance H between the center of gravity GW1 of the tray 76 in the upright state and the rotation center axis RA1 of the drive unit 62, the relationship between the second reference load TB2 and the second load T2 obtained as described above and the mass M can be expressed as follows.

[0075] T2-TB2=MgH (3)

[0076] Where g represents gravitational acceleration.

[0077] Therefore, by transforming equation (3) into

[0078] H = (T2 - TB2) / Mg (4)

[0079] It is possible to estimate (calculate) the distance H of the center of gravity.

[0080] The mass M and the distance H of the center of gravity of pallet 76 can be estimated even when arm 64 is in a position other than the engaged or upright position. For example, Figure 7A As shown, the torque acting on the drive unit 62 when the arm 64 is tilted θ1 degrees relative to the horizontal plane is taken as the first reference load TB1 and the first load T1, and, as Figure 7B As shown, when the torque acting on the drive unit 62 with the arm 64 tilted θ2 degrees relative to the horizontal plane is taken as the second reference load TB2 and the second load T2, the relationship between these loads, the reference load, the mass M and the distance H between the center of gravity is expressed by the following formula.

[0081] T1-TB1=(L×cosθ1-H×sinθ1)Mg (5)

[0082] or,

[0083] T2-TB2=(L×cosθ2-H×sinθ2)Mg (6)

[0084] Where g represents gravitational acceleration.

[0085] Therefore, by combining equations (1) and (6), (3) and (5), or (5) and (6), the mass M and the distance H from the center of gravity can be estimated (calculated). Furthermore, by obtaining the load and the reference load at three or more arm positions and performing univariate regression analysis, the mass M and the distance H from the center of gravity can be estimated more accurately.

[0086] The estimation of mass M and center of gravity distance H by the control device 100 is configured to be performed at any time after the load is acquired. For example, the mass M and center of gravity distance H can be estimated in parallel with the pallet 76 exchange operation performed by the APC arm 50, and the actuator 35 can be activated after the pallet 76 is exchanged. As a result, the work cycle time equivalent to the estimation time can be shortened.

[0087] The estimation of the mass M and the distance H from the center of gravity is based on the assumption that the center of gravity GW1 is located at the center of the pallet. In principle, the center of gravity GW1 of the pallet 76, which contains the workpiece and the fixture, is designed to be located near the center of the pallet. Therefore, it can be said that the mass M and the distance H from the center of gravity can be estimated with a certain degree of accuracy. However, in other words, the workpiece W1 and the fixture 96 are different designs, and the center of gravity GW1 is not strictly located at the center of the pallet. Therefore, under the above assumption, the mass M and the distance H from the center of gravity cannot always be estimated correctly. In this case, the further the center of gravity GW1 is from the center of the pallet in the direction of the reference distance L, the lower the accuracy of the estimated mass M and the distance H from the center of gravity. Therefore, as shown in Figures 8c and 8d, when the position of the center of gravity GW1 of the tray 76 mounted on the worktable 36d is offset in the X-axis direction and / or Y-axis direction (u and / or v in the figure) relative to the rotation center axis CC of the C-axis rotating worktable 36 which rotates about the horizontal direction axis (C-axis), the estimation unit 106 of the control device 100 is configured to estimate these offsets (u and v).

[0088] The specific estimation method will be explained using Figures 8a to 8d. First, as shown in Figures 8a and 8b, the estimation unit 106 of the control device 100 acquires a first load T1 when the arm 64 of the holding tray 76 is in the engaged position and a second load T2 when the arm 64 of the holding tray 76 is in the upright position. Furthermore, as... Figure 5 (b) Figure 6As shown in (b), the first reference load TB1 when the arm 64 is alone, i.e., not holding the tray 76 and in the engaged position, and the second reference load TB2 when not holding the tray 76 and in the engaged position, are acquired and pre-stored in the storage unit 104. Next, as shown in FIG8c, the estimation unit 106 of the control device 100 acquires the first table load T3 (torque) acting on the table 36d at the first table rotation position based on the current value generated in the servo motor 36f of the C-axis rotary table 36 when the C-axis rotary table 36 is in the first table rotation position after the tray 76 is handed over. Specifically, the first table load T3 acting on the table 36d is acquired based on the current value generated in the servo motor 36f using a pre-defined conversion formula between current value and torque. Furthermore, as shown in Figure 8d, the estimation unit 106 of the control device 100 rotates the worktable 36d to a second worktable rotation position, which is 90 degrees different from the first worktable rotation position. Based on the current value generated in the servo motor 36f of the C-axis rotating worktable 36, the second worktable load T4 (torque) acting on the worktable 36d at the second worktable rotation position is obtained. Specifically, using a pre-defined conversion formula between current value and torque, the second worktable load T4, which is the torque acting on the worktable 36d, is obtained based on the current value generated in the servo motor 36f. The various information thus obtained is represented by the following relationship.

[0089] T1-TB1=Mg(L+v) (7)

[0090] T2-TB2=MgH (8)

[0091] T3=Mgu (9)

[0092] T4=Mgv (10)

[0093] Where g represents gravitational acceleration.

[0094] By combining equations (7) to (10), the mass M, the distance H between the center of gravity and the offset (u and v) of the center of gravity GW1 relative to the rotation center axis CC of the C-axis rotary table 36 can be estimated (calculated) as follows:

[0095] M = (T1 - TB1 - T4) / gL (11)

[0096] H = (T2 - TB2) / Mg (12)

[0097] u=T3 / Mg (13)

[0098] v=T4 / Mg (14).

[0099] Thus, the estimation unit 106 can estimate the offset (u and v) of the center of gravity GW1 relative to the rotation center axis CC of the C-axis rotary table 36. Therefore, the maximum rotational speed and acceleration when the table 36d rotates can be set taking into account the offset (u and v). Furthermore, the C-axis rotary table 36 is unloaded when the tray 76 is not held. Therefore, although it is not essential to obtain the reference loads corresponding to the first table load T3 and the second table load T4 in advance, these reference loads can be obtained as needed. In addition, torque acquisition has been described here, but it is not limited to this. Current values ​​can also be obtained from the servo amplifiers 62c and 36h and converted into torque in the control device 100, or the mass and center of gravity position can be directly estimated based on the current values.

[0100] like Figure 4 As shown, the control device 100 includes a calculation unit 108, which calculates the adjustment force acting from the actuator 35 on the first actuator mounting portion 36a and the second actuator mounting portion 36b based on the mass M and center-of-gravity distance H of the tray 76 estimated by the estimation unit 106. This adjustment force is the force used to lift the worktable 36d, which is tilted downwards due to the weight of the mounted tray 76, and to correct the rotation center axis CC of the tilted worktable 36d (tilt correction) to align with the horizontal axis, thereby actuating the actuator 35. In this embodiment, it is hydraulic pressure used to actuate the actuator 35. The relationship between the mass M and center-of-gravity distance H and the hydraulic pressure, or the relationship between the tilting amount estimated based on the mass M and center-of-gravity distance H and the hydraulic pressure, is measured and organized through experiments, and stored in the storage unit 104 in the form of formulas or numerical tables. The control device 100 includes a table position control device 110, which actuates the actuator 35 by applying a calculated adjustment force. This causes the housing 36e to elastically deform via the first actuator mounting portion 36a and the second actuator mounting portion 36b, thereby changing the position or orientation of the table support portion 36c and controlling the position of the table 36d. The table position control device 110 actuates the hydraulic source (fluid pressure source) 112 of the machine tool 10, supplying hydraulic pressure to the actuator 35. This enables the actuator 35 to generate an adjustment force. The table position control device 110 is configured to also take into account the effects of displacement or tilting of the table 36d due to the C-axis rotation of the table 36, correcting the adjustment force of the actuator 35. Specifically, the hydraulic pressure supplied to the actuator 35 is controlled according to the position of the table 36d, which changes due to displacement or tilting. Therefore, the adjustment force can be precisely applied in a manner that corresponds to the change in position (tilt) of the center of gravity GW1 caused by the change in position (tilt) of the rotation center axis CC of the worktable 36d, so that the rotation center axis CC of the worktable 36d is always aligned with the horizontal axis, that is, in a manner that positions the workpiece W1 in the position to be machined.

[0101] Furthermore, the table position control device 110 is configured to change the adjustment force of the actuator 35 based on the progress of the machining process of the workpiece W1 obtained from the NC program and the model information of the workpiece W1 in the NC device 102. Moreover, the table position control device 110 is configured to change the adjustment force generated by the actuator 35 based on the position information (displacement information and tilt information) of the table 36d measured by a position sensor or the like disposed on the C-axis rotary table 36.

[0102] The control device 100 includes a notification unit 100 (not shown), which notifies the operator of an exceedance if the estimated mass M of the tray 76 exceeds the upper limit of the mass that can be mounted on the worktable 36d (worktable mounting limit mass), the upper limit of the mass that the arm 64 can hold (arm holding limit mass), or the upper limit of the mass that the APC arm 50, which is a swivel arm, can hold (APC arm holding limit mass). Therefore, for example, after a change in the posture of the tray 76, before exchanging the tray 76 held by the arm 64 with the tray 94 to be mounted on the C-axis rotary worktable 36, the operator can estimate the mass M of the tray 76. If the mass exceeds the upper limit of the worktable mounting limit or the upper limit of the APC arm holding limit, the operator can stop the tray exchange and issue an alarm to the operator (through a display that can be perceived by sound or light, or a notification to a personal computer, mobile terminal, etc.). It can also estimate the mass immediately after acquiring the first load T1, and issue an alarm without changing the pallet posture if the mass exceeds the arm's maximum possible limit. Therefore, it can prevent malfunctions of the C-axis rotary table 36, arm 64, and APC arm 50, and improve the operating efficiency of the machine tool 10.

[0103] exist Figure 9 The flowchart shows the process of tilting correction. Furthermore, in... Figures 10 to 22 The text indicates the preparation of the tray 76 corresponding to the tilting correction process. Based on these descriptions, the effects of the control device 100 and the estimation method of the machine tool 10 according to the embodiments of the present invention will be explained below. Furthermore, Figures 10 to 22 The side view of the pallet posture changing device 42 and the C-axis rotary table 36 shown is a schematic diagram used to illustrate the effects of these devices. Therefore, from the viewpoint of easy observation of the attached drawings, parts that cannot be directly seen in the actual side view due to being obscured by the arm 64 (such as the claw 72, the receiving part 74, and the arm protrusion 86) and the internal structure of the C-axis rotary table 36 (such as the table support part 36c and the table 36d) are also depicted with solid lines. Please note this.

[0104] Control device 100 proceeds to step S10 (refer to) Figure 9), begin the tilting correction. When starting the tilting correction, proceed to step S20 (refer to...). Figure 9 The pallet is then moved into the pallet orientation changing device 42. Figure 10 The image shows the state where the pallet 76, equipped with the fixture 96 and the workpiece W1 to be processed, is moved in from the outside of the machine tool 10. Here, directly below the pallet orientation changing device 42, the pallet 76 (76b) is placed on the track 90 located above the bed 18. Figure 10 The pallet 76 (the dotted part) is moved horizontally from the outside of the machine tool 10 through the preparation chamber door 14a into the preparation station 40 side, i.e., the pallet posture changing device 42 side. Furthermore, the method of moving the pallet 76 is not limited to the track 90; it can also be moved vertically by a conveyor provided on the upper part of the machine tool, or by using the forks of a forklift. The moved pallet 76 stops sliding by abutting against the stop 92 formed at the end of the track 90 and is positioned in the horizontal preparation position. At this time, the arm 64 is positioned (rotated) to a retracted position lower than the horizontal engagement position, and the pawl 72 is positioned in the pallet engagement release position. The pallet posture changing device 42 is configured such that, in the retracted position, the arm 64 and its constituent elements, the pawl 72, the receiving part 74, and the arm protrusion 86, do not interfere with the moving of the pallet 76. On the other hand, the C-axis rotary table 36 (see reference 12) on the machining chamber side (not shown)... Figure 2 ), and holds a second tray 94 which serves as a tray for assembling the machined (processed) workpiece W2 and the fixture 96.

[0105] When the pallet is moved into the pallet orientation change device 42, the process proceeds to step S30 (refer to step S30). Figure 9 This causes the arm 64 of the pallet attitude changing device 42 to move, maintaining the pallet 76 in a horizontal position. Figure 11 The image shows the state in which the arm 64 is rotated by the drive unit 62 to an engaged position opposite the engaging side 76e of the pallet 76 and positioned relative to the pallet 76. In this state, the arm protrusion 86 and the second pallet receiving surface 74b of the receiving part 74 can be configured to either not contact the pallet 76 or to contact the pallet 76. When not in contact with the pallet 76, the pallet 76 is held on the track 90. ​​When in contact with the pallet 76, the arm protrusion 86 contacts the upper side of the inner wall of the pallet groove 88, and the second pallet receiving surface 74b contacts the lower side 76b of the pallet 76. Therefore, the pallet 76 is removed from the track 90 and held by the arm 64. In this case, since the arm protrusion 86 is inserted into the pallet groove 88, even if an unexpected external force is applied to the pallet 76, it is possible to prevent the pallet 76 from accidentally moving to the outside of the machine tool 10.

[0106] exist Figure 12The diagram shows the state where the pawl 72 moves from the tray engagement release position to the tray engagement position (arrow in the diagram) and engages with the pin 78. Here, the dimensions of the pawl 72 and the pin 78 are set to create a gap (playback) between the pawl 72 and the pin 78 to a degree that prevents the pin 78 from falling off. When the arm 64 holds the tray 76, the process moves to step S40 (see...). Figure 9 The encoder 62b of the servo motor 62a detects that the rotational position of the arm 64 is in the engaged position (the first arm position in the estimation of mass M and center of gravity distance H). Furthermore, a current corresponding to the mass M and center of gravity distance H of the tray 76 is generated in the servo motor 62a of the drive unit 62. The control device 100 (NC device 102) obtains the torque (first load T1) based on the current value at this time from the servo amplifier 62c and stores it in the storage unit 104.

[0107] When the control device 100 acquires the first load T1, it proceeds to step S50 (refer to...). Figure 9 This causes the arm 64 of the pallet orientation changing device 42 to move, rotating the pallet 76 to an upright position. Figure 13 The text indicates that the drive unit 62 rotates the arm 64 to an upright position, changing the posture of the tray 76 to an upright state. During the posture change, since the pawl 72 engages with the pin 78, the movement of the tray 76 in the rotational direction (R1 direction) can be restricted. Furthermore, since the second tray receiving surface 74b abuts against the lower surface 76b of the tray 76, and the first tray receiving surface 74a abuts against the contact side 76d of the tray 76, the weight of the tray 76 can be supported, restricting its movement in the direction of gravity. Thus, the arm 64 can change its posture from a horizontal state to an upright state while stably holding the tray 76. When the tray 76 is rotated to the upright state, the process proceeds to step S60 (see...). Figure 9 The encoder 62b of the servo motor 62a detects that the rotational position of the arm 64 is in the upright position (the second arm position in the estimation of mass M and center of gravity distance H). Furthermore, a current corresponding to the mass M and center of gravity distance H of the tray 76 is generated in the servo motor 62a of the drive unit 62. The control device 100 (NC device 102) acquires the torque (second load T2) based on the current value at this time and stores it in the storage unit 104.

[0108] When the control device 100 acquires the second load T2, it proceeds to step S70 (refer to...). Figure 9 The control device 100 causes the APC arm 50 to move and exchange trays 76 and 94. Figure 14This indicates that the APC arm 50 of the tray exchange device 44 is raised and the tray 76 is held by the first tray holding part 82. Specifically, by raising the APC arm 50, the holding member 76f is inserted into the concave portion of the first tray holding part 82, and the upper surfaces of the columnar members at both ends of the first tray holding part 82 abut against the abutting side 76d of the tray 76. Thus, the APC arm 50 is able to hold the tray 76. At this time, the pawl 72 only restricts the movement of the pin 78 in the individual rotational direction (R1 direction) of the tray 76, so the APC arm 50 can lift the tray 76 without interfering with the arm 64.

[0109] Figure 15 This indicates that, while holding the tray 76, the APC arm 50 moves the gripper 72 from the tray engaging position to the tray disengaged position. As shown by the arrow in the figure, by moving the gripper 72 from the tray engaging position to the tray disengaged position, only the APC arm 50 holds the tray 76. At this time, the second tray 94 on the machining chamber 12 side (not shown) is also unloaded from the C-axis rotary table 36. Thus, the tray 76 on the preparation chamber 14 side and the second tray 94 on the machining chamber 12 side (see reference) are both unloaded. Figure 17 Both are held together by APC arm 50.

[0110] Figure 16 This indicates that the arm 64, which has moved the gripper 72 to the tray engagement release position, is rotated to the standby position by the drive unit 62. The tray posture changing device 42 can position (rotate) the arm 64 to a standby position between the upright position (upright state) and the engagement position (horizontal state). Therefore, when the APC arm 50 and the rotary door 46 are rotated back to change the tray 76 on the preparation chamber 14 side and the second tray 94 on the processing chamber 12 side, interference between the APC arm 50 and the rotary door 46 and the tray posture changing device 42 or other components within the machine tool 10 can be prevented. Furthermore, since the arm 64 can be positioned to the standby position without returning to the engagement position, the time required to rotate the arm 64 can be minimized, thereby reducing the time required for changing and exchanging the tray 76's posture.

[0111] Figure 17 This indicates that the tray 76 on the side of the preparation chamber 14 was replaced (exchanged) by rotating the APC arm 50 (see reference). Figure 16 The state of the second tray 94 on the side of the processing chamber 12. By rotating the APC arm 50 holding the tray 76 and the second tray 94 180 degrees, the tray 76 with the workpiece W1 before processing can be moved to the side of the processing chamber 12 and handed over to the C-axis rotary table 36, and the second tray 94 with the workpiece W2 after processing can be moved to the side of the preparation chamber 14.

[0112] In parallel with or after the exchange of trays 76 and 94, the estimation unit 106 proceeds to step S80 (see reference). Figure 9 Using equations (1) and (2) above, the mass M is estimated based on the reference distance L, the first reference load TB1, and the first load T1 stored in the storage unit 104. Next, the estimation unit 106 proceeds to step S90 (refer to...). Figure 9 Using equations (3) and (4) above, the distance H of the center of gravity is estimated based on the second reference load TB2 and the second load T2 stored in the storage unit 104. At this time, the first reference load TB1 and the second reference load TB2 are obtained in advance through experiments, etc., and stored in the storage unit 104. Then, proceed to step S100 (refer to...). Figure 9 In order to perform tilt correction, the calculation unit 108 of the control device 100 calculates the adjustment force acting from the actuator 35 on the first actuator mounting part 36a and the second actuator mounting part 36b based on the mass M of the tray 76 estimated by the estimation unit 106 and the distance H of the center of gravity.

[0113] Figure 18 The C-axis rotary table 36 is shown with the replaced pallet 76 mounted. The APC arm 50 rotates 180 degrees, changing the pallet 76 to the side of the machining chamber 12. The replaced pallet 76 is then positioned and mounted on the C-axis rotary table 36. During the rotation of the APC arm 50, the C-axis rotary table 36 is in a standby position that does not interfere with the APC arm 50 or the pallet 76 it holds. Figure 18 The C-axis rotary table 36 waits at the position indicated by the dotted line until it has fully rotated. After rotating, the C-axis rotary table 36 moves along the Z-axis toward the APC arm 50 and the tray 76. The tray 76 is held and mounted by the mounting mechanism (not shown) on the mounting surface of the C-axis rotary table 36, which is located below the tray 76b.

[0114] Figure 19This is a side view of the APC arm 50 transferring pallet 76 to the C-axis rotary table 36. When pallet 76 is mounted on the C-axis rotary table 36, the APC arm 50 descends, disengaging from the pallet 76 transferred to the C-axis rotary table 36. The holding provided by the APC arm 50 is released, thus the pallet 76 is held only by the mounting surface of the table 36d of the C-axis rotary table 36. The pallet 76, fixture 96, and workpiece W1 are mounted upright on the mounting surface of the table 36d, protruding horizontally. Therefore, a torque generated by the weight of the pallet 76, fixture 96, and workpiece W1 acts on the table 36d, resulting in the table 36d tilting vertically downwards. The rotation axis (C-axis) of the table 36d tilts vertically downwards relative to the horizontal axis, a phenomenon known as tipping, which reduces machining accuracy. When machining workpiece W1 in a tilted state, for example, the parallelism requirement of the upper surface 76a of workpiece W1 relative to the reference surface of the reference surface mounted on fixture 96 cannot be met.

[0115] Figure 20 This is a side view showing the tray 76 and workpiece W1, indicating that the worktable 36d is tilted (tipping) due to its own weight. When the tray 76 is handed over to the C-axis rotary table 36, the process moves to step S110 (refer to...). Figure 9 The control device 100 activates the worktable position control device 110 to perform tilt correction, and controls the hydraulic source 112 to activate the actuator 35 by means of the adjustment force (hydraulic) calculated by the calculation unit 108.

[0116] Figure 21 This is a side view of the C-axis rotary table 36, which actuates the actuator 35 for tilt correction. When the table position control device 110 controls the hydraulic source 112 to actuate the actuator 35, the process moves to step S120 (see reference). Figure 9 The actuator 35 actuates, causing the housing 36e of the C-axis rotating table 36 to elastically deform. Specifically, the actuator 35 is actuated by a hydraulic supply, applying an adjustment force to the first actuator mounting portion 36a and the second actuator mounting portion 36b. Therefore, a force is applied to the housing 36e in a direction away from or towards it, causing the housing 36e to elastically deform towards the rear side (actuator 35 side), tilting (standing up). As a result, the rotation center axis CC of the table 36d, which tilts downwards along with the fixture 96, workpiece W1, and pallet 76, is corrected to be along the horizontal axis, and the table 36d is positioned in its proper place. When the table 36d is positioned, the process proceeds to step S130 (see...). Figure 9 ), and end the tilting correction.

[0117] Figure 22This is a side view of the C-axis rotary table 36, which rotates towards the spindle 26 via the B-axis rotary table 34 for machining. The workpiece W1, mounted on a pallet 76 that rotates via the B-axis rotary table 34 and is positioned opposite the spindle 26, is machined by a tool 28 mounted on the spindle 26 through relative movement between the spindle 26, the C-axis rotary table 36, and the B-axis rotary table 34. After machining, the pallet 76 is exchanged again.

[0118] According to the control device 100 of the machine tool 10 of this embodiment, the control device 100 includes a storage unit 104, which stores a first reference load TB1 acting on the drive unit 62 when the arm 64 is rotated to the first arm position, a second reference load TB2 acting on the drive unit 62 when the arm 64 is rotated to the second arm position, and a horizontal distance L between the central portion of the pallet 76 in the horizontal state and the rotation center axis RA1 of the drive unit 62. In addition, the control device 100 includes an estimation unit 106, which acquires the first load T1 acting on the drive unit 62 when the pallet 76 held by the arm 64 is changed to the first arm position within the arm rotation range, and the second load T2 acting on the drive unit 62 when the pallet 76 is changed to the second arm position, and estimates the mass M and the position of the center of gravity GW1 (center of gravity position distance H) of the pallet 76 based at least on the reference distance L, the first reference load TB1, the second reference load TB2, the first load T1, and the second load T2. Therefore, the mass M and center of gravity distance H of the pallet 76 can be estimated without increasing the number of parts by using the drive unit 62 and the arm 64.

[0119] Furthermore, according to the machine tool 10 of this embodiment, the machine tool 10 includes an actuator 35 and a calculation unit 108. The calculation unit 108 calculates the adjustment force of the actuator 35 acting on the first actuator mounting portion 36a and the second actuator mounting portion 36b based on the mass M of the pallet 76 and the distance H of the center of gravity position estimated by the control device 100. In addition, the machine tool 10 includes a table position control device 110, which actuates the actuator 35 such that the calculated adjustment force acts on the first actuator mounting portion 36a and the second actuator mounting portion 36b, causing the housing 36e to elastically deform and changing the position or posture of the table support portion 36c, thereby controlling the position of the table 36d. As a result, tilt correction of the table 36d can be performed, and the machining accuracy of the workpiece W1 can be improved.

[0120] Furthermore, according to the machine tool 10 of this embodiment, the estimation unit 106 of the control device 100 can obtain the first table load T3 acting on the table 36d when the C-axis rotary table 36 is in the first table rotation position after the pallet 76 has been handed over. Furthermore, the estimation unit 106 of the control device 100 can rotate the table 36d to a second table rotation position, which is 90 degrees rotated from the first table rotation position, and obtain the second table load T4 acting on the table 36d. Therefore, the offset of the center of gravity GW1 relative to the rotation center axis CC of the C-axis rotary table 36 can be estimated.

[0121] Furthermore, according to the machine tool 10 of this embodiment, the control device 100 has a notification unit 100 that notifies the operator if the estimated mass M of the pallet 76 exceeds the maximum possible mass for table installation, the maximum possible mass for holding, or the maximum possible mass for APC arm holding stored in the storage unit 104. Therefore, it is possible to estimate the mass M of the pallet 76 after a change in the pallet 76's posture but before exchanging the pallet 76 held by the arm 64 with the pallet 94 mounted on the C-axis rotary table 36. If the mass M exceeds the maximum possible mass for table installation or the maximum possible mass for APC arm holding, the pallet exchange is stopped, and the operator is notified. It is also possible to estimate the mass immediately after acquiring the first load T1, and if the mass exceeds the maximum possible mass for arm holding, an alarm is issued without changing the pallet's posture. Thus, malfunctions of the C-axis rotary table 36, arm 64, and APC arm 50 can be prevented, improving the operating efficiency of the machine tool 10.

[0122] Furthermore, according to the machine tool 10 of this embodiment, the control device 100 is configured to control the speed and / or acceleration of the movement of the arm 64, the APC arm 50, and the feed axis of the machine tool 10 based on the estimated mass M of the pallet 76 and the distance H between the center of gravity and the pallet 76. Therefore, when the mass M is greater than a certain proportion of the maximum possible mass of the APC arm, the rotation speed and lifting speed of the APC arm 50 of the pallet exchange device 44 can be set to be relatively small. In addition, when the center of gravity GW1 is positioned such that the load on the C-axis is relatively small, the acceleration / rotational acceleration of the C-axis, B-axis, and Z-axis can be set to be relatively large; conversely, when the center of gravity GW1 is positioned such that the load on the C-axis is relatively large, the acceleration / rotational acceleration of the C-axis, B-axis, and Z-axis can be set to be relatively small. Therefore, the machining accuracy of the workpiece W1 and the operating efficiency of the machine tool can be improved.

[0123] As described above, according to the control device 100 and estimation method of the machine tool 10 according to this embodiment, in order to improve the machining accuracy and operating efficiency of the workpiece W1, the mass M and center-of-gravity distance H of the pallet 76 on which the workpiece W1 is mounted can be estimated with high accuracy without increasing the number of parts. Furthermore, the estimated mass M and center-of-gravity distance H of the pallet 76 can be applied to various scenarios of the machine tool 10 to improve the machining accuracy of the workpiece W1 and the operating efficiency of the machine tool 10.

[0124] The above describes the implementation of the control device 100 of the machine tool 10 and the method for estimating the distance H between the mass M and the center of gravity. However, the present invention is not limited to the above-described implementation. In addition to the above, those skilled in the art should understand that various modifications can be made to the above-described implementation.

[0125] Explanation of reference numerals in the attached figures

[0126] 10 machine tools

[0127] 26 Spindle

[0128] 28 tools

[0129] 35 Actuators

[0130] 36 C-axis rotary table (worktable)

[0131] 36a First Actuator Mounting Section

[0132] 36b Second Actuator Mounting Section

[0133] 36c Workbench Support

[0134] 36D workbench

[0135] 36e housing

[0136] 36f servo motor

[0137] 36g encoder

[0138] 36h Servo Amplifier

[0139] 38 Z-axis linear guide rail

[0140] 40 Preparation Station

[0141] 42. Pallet posture changing device (estimation device)

[0142] 44. Tray exchange device

[0143] 60 base

[0144] 62 Drive Unit

[0145] 64 arms

[0146] 76 pallets

[0147] 76a above

[0148] 96 Fixtures

[0149] 100 Control device

[0150] 104 Storage Department

[0151] 106 Presumption Department

[0152] 108 Computing Department

[0153] 110 Workbench Position Control Device

[0154] H Distance from the center of gravity

[0155] L reference distance

[0156] M mass

[0157] RA1 drive unit rotation center shaft

[0158] TB1 First Reference Load

[0159] TB2 Second Reference Load

[0160] T1 First Load

[0161] T2 Second Load

[0162] T3 First Workbench Load

[0163] T4 Second Workbench Load

[0164] W1 workpiece

[0165] W2 workpiece

Claims

1. A device for estimating the mass and center of gravity of a pallet on which workpieces are mounted, wherein, The estimation device includes: Base; A drive unit, which is mounted on the base, is configured to enable the tray to rotate about a rotation center axis extending in a horizontal direction and to acquire a load. An arm, rotatably mounted on the drive unit, holds the tray with the upper surface for assembling the workpiece, and is used to change posture within a range of arm rotation, including a horizontal state after moving the upper surface of the tray to the horizontal plane and an upright state after moving the upper surface of the tray to the vertical plane. The storage unit stores a first reference load acting on the drive unit when the arm rotates to a first arm position within the arm's rotation range, a second reference load acting on the drive unit when the arm rotates to a second arm position within the arm's rotation range that is different from the first arm position, and the horizontal distance, i.e., the reference distance, between the central portion of the tray and the rotation center axis of the drive unit in the horizontal state. as well as The estimation unit acquires a first load acting on the drive unit when the pallet held by the arm changes its posture to a first arm position within the rotation range of the arm, and a second load acting on the drive unit when the posture changes to a second arm position within the rotation range of the arm, and estimates the mass and center of gravity position of the pallet based at least on the reference distance, the first reference load, the second reference load, the first load, and the second load.

2. A method for estimating the mass and center of gravity of a pallet on which workpieces are mounted, wherein, include: Using an arm rotatably mounted to a drive unit configured to acquire a load, the pallet having an upper surface for assembling the workpiece is held, and the posture is changed within a range of arm rotation, including a horizontal state after moving the upper surface of the pallet to the horizontal plane and an upright state after moving the upper surface of the pallet to the vertical plane. When the arm is rotated to the first arm position within the arm's rotation range, a first reference load is obtained acting on the drive unit; When the arm is rotated to the second arm position within the rotation range of the arm, a second reference load is obtained acting on the drive unit; The first load acting on the drive unit is obtained when the tray held by the arm changes its posture to the first arm position within the rotation range of the arm; The second load acting on the drive unit is obtained when the tray held by the arm changes its posture to a second arm position within the rotation range of the arm; and Based on the horizontal distance, i.e., the reference distance, between the central portion of the pallet and the rotation center axis of the drive unit in the horizontal state, and at least the first reference load, the second reference load, the first load, and the second load, the mass and center of gravity of the pallet are estimated.

3. A machine tool, comprising: Spindle, the spindle being used to mount tools; A workbench that receives the tray with the workpiece mounted on it from the arm and can be mounted in the upright position; The housing integrally comprises a worktable support portion for supporting the worktable, a first actuator mounting portion, and a second actuator mounting portion; An actuator is mounted on the first actuator mounting portion and the second actuator mounting portion, and applies a force to the first actuator mounting portion and the second actuator mounting portion in a direction away from or close to the housing, causing the housing to elastically deform. The estimating device as described in claim 1; The calculation unit, based on the mass and center of gravity position of the tray estimated by the estimation device, calculates the adjustment force exerted by the actuator on the first actuator mounting portion and the second actuator mounting portion; and A worktable position control device, wherein the worktable position control device causes the actuator to move by applying the calculated adjustment force to the first actuator mounting part and the second actuator mounting part, thereby causing the housing to elastically deform and changing the position or posture of the worktable support part, thereby controlling the position of the worktable.

4. The machine tool as described in claim 3, wherein, The worktable is configured to rotate and acquire a load when the tray is mounted on it. The estimation unit obtains the first workbench load acting on the workbench on which the tray is mounted at the first workbench rotation position, and the second workbench load acting on the workbench on which the tray is mounted at the second workbench rotation position after the workbench has been rotated 90 degrees from the first workbench rotation position. Based on the reference distance, the first reference load, the second reference load, the first load, the second load, the first workbench load, and the second workbench load, the mass and center of gravity of the pallet are estimated.

5. The machine tool as described in claim 3 or 4, wherein, The estimation device includes a notification unit that notifies if the estimated mass of the tray exceeds the maximum possible mass of the workbench stored in the storage unit or the maximum possible mass of the arm.

6. The machine tool as described in claim 3 or 4, wherein, The estimation device is configured to control the speed and / or acceleration of the arm and the feed axis of the machine tool based on the estimated mass of the pallet and the center of gravity position of the pallet.

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