Tool transport device and machine tool

Abstract

Provided are a tool transport device and a machine tool that can suppress an increase in the number of detection units that detect the state of a grasping part. A tool transport device according to the present invention comprises a grasping part that can be in a grasping state in which the grasping part is grasping a tool or a not-grasping state in which the grasping part is not grasping the tool, a first detection unit that detects whether the grasping part is in the grasping state, a second detection unit that detects whether the grasping part is in the not-grasping state, and a determination unit that determines whether the grasping part is in an abnormal state that is different from the grasping state and the not-grasping state on the basis of detection results from the first detection unit and the second detection unit.

Description

Tool transport device and machine tool

[0001] The present technology relates to a tool transport device that transports a tool and a machine tool.

[0002] There is a machine tool that includes a first magazine, a second magazine, and a tool carrier that carries tools between the first magazine and the second magazine. The tool carrier includes a pod that holds the tools (see Patent Document 1).

[0003] International Publication No. 2022 / 004484

[0004] A machine tool may need to detect whether a pod is holding a tool, not holding a tool, or the tool has fallen off the pod. If multiple detectors corresponding to each state are provided, the number of detectors increases, which can increase costs and lead to complicated wiring.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a tool transport device and a machine tool that can suppress an increase in the number of detection units that detect the state of the gripping unit.

[0006] A tool transport device according to one embodiment of the present disclosure includes a gripping unit that can be in a gripping state in which it grips a tool or a non-gripping state in which it does not grip the tool, a first detection unit that detects whether the gripping unit is in the gripping state, a second detection unit that detects whether the gripping unit is in the non-gripping state, and a determination unit that determines whether the gripping unit is in an abnormal state different from the gripping state and the non-gripping state based on detection results of the first detection unit and the second detection unit.

[0007] In the present disclosure, whether the gripping unit is in an abnormal state different from the gripping state and the non-gripping state is determined based on the detection results of the first detection unit and the second detection unit. In other words, three states can be detected by two detection units, and an increase in the number of detection units can be suppressed.

[0008] In one embodiment of the tool transport device of the present disclosure, when the first detection unit detects that the tool is not in the gripping state and the second detection unit detects that the tool is not in the non-gripping state, the judgment unit judges that the gripping unit is in the abnormal state.

[0009] In the present disclosure, it can be reliably determined that the gripping portion is in an abnormal state based on the detection by the first detection unit and the second detection unit.

[0010] A tool transport device according to one embodiment of the present disclosure includes a moving unit that moves the gripping unit, and when the position of the moving unit is in a first range, the first detection unit detects that the gripping unit is in the gripping state.

[0011] In the present disclosure, whether or not the hand is in a gripping state is detected based on whether or not the moving part is in the first range.

[0012] In one embodiment of the tool transport device of the present disclosure, when the position of the moving part is in a second range different from the first range, the second detection part detects that the gripping part is in the non-gripping state.

[0013] In the present disclosure, whether or not the robot is in a non-gripping state is detected based on whether or not the moving part is in the second range.

[0014] In the tool transport device according to one embodiment of the present disclosure, the first detection unit includes a proximity sensor.

[0015] In the present disclosure, a proximity sensor determines whether the moving part is in the first range.

[0016] In the tool transport device according to one embodiment of the present disclosure, the second detection unit includes a proximity sensor.

[0017] In the present disclosure, the proximity sensor determines whether the moving part is in the second range.

[0018] The tool transport device according to one embodiment of the present disclosure includes a notification unit that notifies the user of the abnormal state when the determination unit determines that the gripper is in the abnormal state.

[0019] In the present disclosure, the occurrence of an abnormality is notified.

[0020] A tool transport device according to one embodiment of the present disclosure includes a gripping unit that can be in a gripping state in which it grips a tool or in a non-gripping state in which it does not grip the tool, a moving unit that moves the gripping unit, a first detection unit that detects whether the moving unit is in a first detection range, a second detection unit that detects whether the moving unit is in a second detection range that is different from the first detection range, and a determination unit that determines whether the gripping unit is in an abnormal state that is different from the gripping state and the non-gripping state based on detection results of the first detection unit and the second detection unit.

[0021] In the present disclosure, it is determined whether the gripping portion is in an abnormal state different from the gripping state and the non-gripping state based on the detection results of the first detection portion and the second detection portion.

[0022] A machine tool according to one embodiment of the present disclosure includes a spindle to which a tool is attached, a gripping unit that can be in a gripping state in which it grips the tool or a non-gripping state in which it does not grip the tool, a first detection unit that detects whether the gripping unit is in the gripping state, a second detection unit that detects whether the gripping unit is in the non-gripping state, and a determination unit that determines whether the gripping unit is in an abnormal state different from the gripping state and the non-gripping state based on the detection results of the first detection unit and the second detection unit.

[0023] In the present disclosure, the determination unit determines whether the gripping unit is in an abnormal state different from the gripping state and the non-gripping state based on the detection results of the first detection unit and the second detection unit.

[0024] In the tool transport device and machine tool according to an embodiment of the present disclosure, it is determined whether the gripper is in an abnormal state different from the gripping state and the non-gripping state based on the detection results of the first and second detectors. In other words, three states can be detected by two detectors, and an increase in the number of detectors can be suppressed.

[0025] 6 is a schematic front view of a machine tool. FIG. 7 is a schematic plan view of a first magazine, a second magazine, and a tool transport device. FIG. 8 is a schematic sectional view taken along line III-III in FIG. 2. FIG. 9 is a rear perspective view of the vicinity of the second magazine. FIG. 10 is a block diagram showing a control device, a motor, a first detection unit, a second detection unit, a solenoid valve, and a notification unit. FIG. 11 is a schematic front view of a pod in an ungripped state. FIG. 12 is a schematic sectional view taken along line VII-VII in FIG. 6. FIG. 13 is a schematic sectional view of a pod in a gripped state. FIG. 14 is a schematic sectional view of a pod in an abnormal state. FIG. 15 is an explanatory diagram illustrating the relationship between the position of a piston and the detection ranges of the first and second detection units. FIG. 16 is a table showing the relationship between the range in which the piston is located, the detection results of the first and second detection units, and the state of the hand. FIG. 17 is a diagram showing a state in which a pod is placed at position A. FIG. 18 is a diagram showing a state in which a pod is placed at position B. FIG. 19 is a diagram showing a state in which a pod is placed at position C. FIG. 19 is a flowchart illustrating a process of transferring a tool from the second magazine to the first magazine by the control device. FIG. 19 is a flowchart illustrating a process of transferring a tool from the first magazine to the second magazine by the control device.

[0026] The present disclosure will be described below with reference to the drawings showing a machine tool according to an embodiment. Fig. 1 is a schematic front view of the machine tool, Fig. 2 is a schematic plan view of the first magazine, the second magazine, and the tool transport device, Fig. 3 is a schematic cross-sectional view taken along line III-III in Fig. 2, and Fig. 4 is a rear perspective view of the vicinity of the second magazine. In the following description, the terms up, down, front, back, left, and right shown in the drawings will be used.

[0027] The machine tool includes a base 1, a workpiece holder 2, an XY movement mechanism 3, a pillar 4, a Z movement mechanism 5, a first magazine 6, a support 7, a second magazine 80, a tool transport device 9 (see Figures 2 and 3), a spindle head 10, etc.

[0028] The base 1 has a rectangular shape in a plan view and extends in the front-to-rear direction. A workpiece holder 2 is provided on the upper front side of the base 1. An XY movement mechanism 3 is provided on the upper part of the base 1, behind the workpiece holder 2, that is movable in the left-right direction (X direction) and the front-to-rear direction (Y direction).

[0029] A pillar 4 is provided above the XY movement mechanism 3. A Z movement mechanism 5 that can move up and down (Z direction) is provided in front of the pillar 4. A spindle head 10 is provided on the Z movement mechanism 5. The spindle head 10 has a spindle that extends up and down. A tool 50 is attached to the lower end of the spindle.

[0030] A first magazine 6 is provided in front of the spindle head 10. The first magazine 6 is connected to the upright 4 via a connecting member. The first magazine 6 includes a disk 6a and an arm 6b. A motor 6f (see FIG. 5) is connected to the disk 6a, and the disk 6a rotates around its central axis when driven by the motor 6f. A plurality of arms 6b are provided radially around the periphery of the disk 6a. The arms 6b hold tools 50.

[0031] The first magazine 6 is positioned so that the central axis of the disk 6a extends in the front-to-rear direction and the disk 6a is tilted forward. The lower end position of the first magazine 6 is the tool 50 change position. When loading a tool 50 onto the spindle, the arm 6b holding the tool 50 is positioned at the tool change position, and the Z-movement mechanism 5 is moved downward. As the Z-movement mechanism 5 moves downward, the spindle loads the tool 50 held by the arm 6b. When removing the tool 50 from the spindle, the arm 6b not holding the tool 50 is positioned at the tool change position, and the Z-movement mechanism 5 is moved upward. As the Z-movement mechanism 5 moves upward, the arm 6b grips the tool 50 on the spindle, and the tool 50 is removed from the spindle.

[0032] A tool 50 attached to the spindle processes a workpiece held by the workpiece holder 2. An XY movement mechanism 3 adjusts the front-to-back and left-to-right position of the tool 50 (spindle) relative to the workpiece, and a Z movement mechanism 5 adjusts the up-down position of the tool 50.

[0033] The support portion 7 is provided on the left rear side of the base 1. The support portion 7 extends upward, and a second magazine 80 is provided at its tip. The second magazine 80 is disposed on the left and rear side of the first magazine 6. The second magazine 80 is equipped with a tool transfer device 9. The tool transfer device 9 transfers tools 50 between the arm 6b of the first magazine 6 and the arm 83 of the second magazine 80.

[0034] The cutting line in Figure 2 is perpendicular to the central axis 81a of the support disk 81. The first magazine 6 is provided with a cover 6d. The cover 6d covers the outside of each arm 6b. The cover 6d is rotatable and rotates together with the arm 6b during tool exchange with the spindle, so as not to interfere with tool exchange.

[0035] As shown in Figure 4, a mounting member 70 is fixed to the upper end of the support part 7. The mounting member 70 includes a front plate part 70a, a rear plate part 70b, and a support cylinder 70c. The front plate part 70a and the rear plate part 70b extend from the upper end of the support part 7 in an upper right direction and are aligned in a front-to-rear direction. The support cylinder 70c has its axial direction in the left-to-right direction and is connected to the upper ends of the front plate part 70a and the rear plate part 70b.

[0036] A reduction gear device 71 is connected to the right part of the support cylinder 70c. The reduction gear device 71 has an annular inner peripheral portion 72 and an outer peripheral portion 73. The inner peripheral portion 72 is fixed to the periphery of the support cylinder 70c. The outer peripheral portion 73 is attached around the inner peripheral portion 72 so as to be rotatable about its axis. In other words, the inner peripheral portion 72 rotatably supports the outer peripheral portion 73.

[0037] The second magazine 80 includes a support disk 81, a motor 82, and multiple arms 83. The support disk 81 forms a rotating disk. The motor 82 is connected to the left portion of the support cylinder 70c. The support disk 81 is disposed on the right side of the reduction gear device 71, with both sides facing left and right. The right side of the support disk 81 faces slightly rearward, and the left side faces slightly forward. A through-hole 81b (see Figure 3) penetrating from left to right is provided in the center of the support disk 81. The support cylinder 70c and the inner peripheral portion 72 extend axially and are inserted into the through-hole 81b. The outer peripheral portion 73 is connected to the left edge of the through-hole 81b. When the motor 82 is driven, the outer peripheral portion 73 rotates, and the support disk 81 rotates around its central axis 81a. The central axis 81a forms a rotation axis and extends horizontally.

[0038] 3 and 4, the arms 83 are arranged along the periphery of the support disk 81. The arms 83 extend in the radial direction of the support disk 81. One end 83f of each arm 83 protrudes radially outward from the periphery of the support disk 81. The one end 83f grips the tool 50.

[0039] 1 , the arm 6b of the first magazine 6 and the arm 83 of the second magazine 80 are closest to each other at a position below the central axis 81a. This closest position is the magazine tool change position P where the tool 50 in the first magazine 6 is changed with the tool 50 in the second magazine 80. Hereinafter, the arm 6b of the first magazine 6 arranged at the magazine tool change position P will be referred to as the change position arm 6c, and the arm 83 of the second magazine 80 will be referred to as the change position arm 84. Tool change is performed between the change position arm 6c and the change position arm 84.

[0040] The tool transport device 9 is provided to the right of the support disk 81. The tool transport device 9 includes a motor 9a, a ball screw 9b, a nut 9c, a track 9d, a slider 9e, a pod 9f, and a connecting portion 9g. The support cylinder 70c inserted into the through-hole 81b and the inner peripheral portion 72 support the ball screw 9b and the track 9d. The ball screw 9b is connected to the rotation shaft of the motor 9a. The nut 9c is connected to the ball screw 9b.

[0041] As shown in FIG. 3 , the track 9d is disposed next to the ball screw 9b. The track 9d is fixed at a position offset from the central axis 81a of the support disk 81. The track 9d extends along the longitudinal direction of the exchange position arm 84. One end of the track 9d faces the exchange position arm 84. The slider 9e is slidably mounted on the track 9d. The pod 9f is attached to the slider 9e. The connecting portion 9g connects the slider 9e to the nut 9c. The ball screw 9b rotates when driven by the motor 9a, and the nut 9c moves along the ball screw 9b. As the nut 9c moves, the slider 9e, the connecting portion 9g, and the pod 9f move along the track 9d. The pod 9f is gripped by the exchange position arm 84 and then passed to the exchange position arm 6c, or the exchange position arm 6c grips the tool 50 and then passes it to the exchange position arm 84.

[0042] FIG. 5 is a block diagram showing a control device 60, motors 6f, 9a, and 82, a first detection unit 61, a second detection unit 62, a solenoid valve 63, and an alarm unit 64. The machine tool is equipped with the control device 60. The control device 60 includes a control unit 60a, a main memory unit 60b, an auxiliary memory unit 60c, and an input / output interface (I / F) 60d. The control unit 60a includes, for example, a processor or a logic circuit. The processor includes, for example, a CPU, an MPU, or a GPU. The logic circuit includes, for example, an FPGA or an ASIC. The main memory unit 60b includes, for example, a RAM. The auxiliary memory unit 60c includes a rewritable storage device, for example, an EEPROM, a flash ROM, or a hard disk. The I / F 60d is an interface connected to the motors 6f, 9a, and 82, the first detection unit 61, the second detection unit 62, the solenoid valve 63, the alarm unit 64, and the like.

[0043] The first detection unit 61 and the second detection unit 62 each include a proximity sensor. The proximity sensor is, for example, a proximity sensor that detects magnetic force. The solenoid valve 63 is a valve that controls the supply of air to a first port 90a and a second port 90b (see FIG. 6 ), which will be described later. The first port 90a and the second port 90b are connected to an air source (not shown) that supplies compressed air. The solenoid valve 63 is provided between the air source and the first port 90a and the second port 90b. The solenoid valve 63 is switchable between a first position in which compressed air is supplied to the first port 90a and air is discharged from the second port 90b, and a second position in which air is discharged from the first port 90a and compressed air is supplied to the second port 90b. The alarm unit 64 is, for example, a display screen, a lamp, a buzzer, etc., and, when an abnormality is detected, alerts the user of the abnormality by displaying information indicating the abnormality, illuminating or flashing a light, or emitting a sound.

[0044] The auxiliary memory unit 60c stores a control program. The control unit 60a reads the control program from the auxiliary memory unit 60c into the main memory unit 60b and executes it. The control unit 60a stores data generated by the execution of the control program in the auxiliary memory unit 60c. The control unit 60a transmits drive signals to the motors 6f, 9a, 82, the solenoid valve 63, and the alarm unit 64 via the input / output I / F 60d as necessary. The control unit 60a receives detection results from the first detection unit 61, the second detection unit 62, etc. via the input / output I / F 60d.

[0045] The control program may be stored in a storage medium 65, such as an optical disk, a flash memory, or a hard disk, and may be downloaded from the storage medium 65 to the auxiliary storage unit 60c. Alternatively, the control program may be downloaded from an external server via a network (not shown) to the auxiliary storage unit 60c. Processing by the control program, such as the abnormality determination processing described below, may be performed by a server or a terminal connected to the control device 60 via the network, or may be performed by distributed processing between the server and a device other than the server, such as a terminal or a second server.

[0046] Fig. 6 is a schematic front view of the pod 9f in an unclasped state, and Fig. 7 is a schematic cross-sectional view taken along line VII-VII in Fig. 6. The pod 9f includes a cylinder 90, a piston 91, a rod 92, a support plate 93, two pivots 94, two arms 95, two hands 96, and a connecting shaft 97.

[0047] The cylinder 90 comprises a cylindrical portion extending in the front-to-rear direction, a front portion provided at the front end of the cylindrical portion, and a rear portion provided at the rear end of the cylindrical portion. A support plate 93 is provided at the front portion of the cylinder 90. A chamber 90c is provided inside the cylinder 90. A piston 91 is housed in the chamber 90c. The piston 91 is movable in the axial direction of the cylinder 90. A rod 92 protrudes forward from the piston 91, passes through the front portion of the cylinder 90 and the support plate 93, and protrudes from the support plate. The rod 92 moves back and forth as the piston 91 moves back and forth. The piston 91 corresponds to a moving part.

[0048] Two protrusions 93a protrude forward from the support plate 93. The two protrusions 93a are spaced apart vertically, and the rod 92 is located between the two protrusions 93a in the vertical direction. The protrusions 93a extend left and right. A pivot 94 extending vertically is provided between the left end of the upper protrusion 93a and the left end of the lower protrusion 93a. Another pivot 94 extending vertically is provided between the right end of the upper protrusion 93a and the right end of the lower protrusion 93a.

[0049] An arm 95 is connected to each of the left and right pivot shafts 94. As shown in Figure 7, the arm 95 has an L-shape in plan view, with a first side 95a and a second side 95b connected at a substantially right angle. A corner 95c of the arm 95 is connected to the pivot shaft 94.

[0050] A first side 95a of the left arm 95 protrudes to the right from a corner 95c of the arm 95, and a second side 95b of the left arm 95 protrudes forward from the corner 95c of the arm 95. A first side 95a of the right arm 95 protrudes to the left from the corner 95c of the arm 95, and a second side 95b of the right arm 95 protrudes forward from the corner 95c of the arm 95.

[0051] The first side portion 95 a of the left arm 95, the first side portion 95 a of the right arm 95, and the rod 92 are connected by a connecting shaft 97. The first side portion 95 a of the left arm 95 and the first side portion 95 a of the right arm 95 are rotatable around the axis of the connecting shaft 97.

[0052] A hand 96 is provided on the right side of the second side 95b of the left arm 95. A hand 96 is provided on the left side of the second side 95b of the right arm 95. The hand 96 corresponds to a gripping portion.

[0053] The hands 96 are columnar and extend vertically. A curved surface is formed on the right surface of the left hand 96 so as to protrude leftward in a plan view. A curved surface is formed on the left surface of the right hand 96 so as to protrude rightward in a plan view. The curvature of the curved surface corresponds to the curvature of the peripheral surface of the tool 50.

[0054] When the solenoid valve 63 is switched to the second position, compressed air is supplied to the rear side of the chamber 90c from the second port 90b, and air from the front side of the chamber 90c is exhausted from the first port 90a. As shown in Fig. 7, the piston 91 is located at the front end of the chamber 90c, and the rod 92 moves forward. The two second sides 95b are inclined relative to the rod 92 so that the distance between the two second sides 95b in the left-right direction increases toward the front. In other words, the two hands 96 are spaced apart from each other and are in a non-gripping state in which they are not gripping the tool 50.

[0055] FIG. 8 is a schematic cross-sectional view of the pod 9f in a gripping state. When the solenoid valve 63 is switched to the first position, air in the rear of the chamber 90c is exhausted from the second port 90b, and compressed air is supplied to the front of the chamber 90c from the first port 90a. As shown in FIG. 8, the piston 91 is positioned in the center of the chamber 90c in the front-to-rear direction, and the rod 92 moves further rearward than in the state shown in FIG. 7. The two second sides 95b are approximately parallel to each other. That is, the two hands 96 are closer to each other than in the state shown in FIG. 7, and are in a gripping state in which they grip the tool 50. Note that the postures and positions of the piston 91, rod 92, arm 95, and hand 96 in FIG. 8 are those when the two hands 96 are gripping the tool 50, i.e., when the hand 96 is prevented from approaching by the tool 50.

[0056] FIG. 9 is a schematic cross-sectional view of a pod 9f in an abnormal state. An abnormal state occurs, for example, when a hand 96 is holding a tool 50 and the tool 50 falls off the hand 96. As shown in FIG. 9, the piston 91 is located at the rear end of the chamber 90c, and the rod 92 moves rearward. The two second sides 95b are inclined relative to the rod 92 so that the distance between the two second sides 95b in the left-right direction decreases toward the front. In other words, the two hands 96 are positioned too close to each other, resulting in an abnormal state. In the abnormal state, the tool 50 does not prevent the hands 96 from approaching each other, so the two hands 96 approach each other too closely.

[0057] As shown in Figure 6, a first detector 61 and a second detector 62 are attached to the right side of the cylinder 90. The first detector 61 is located at the rear of the cylinder 90, and the second detector 62 is located at the front of the cylinder 90. That is, the first detector 61 and the second detector 62 are spaced apart from each other in the front-to-rear direction.

[0058] The piston 91 is equipped with a magnet. The first detection unit 61 and the second detection unit 62 are equipped with magnetic sensors. The first detection unit 61 detects whether the piston 91 is located in the center of the chamber 90c in the front-to-rear direction, i.e., whether the hand 96 is in a gripping state. The second detection unit 62 detects whether the piston 91 is located in the front end portion of the chamber 90c, i.e., whether the hand 96 is in a non-gripping state. The magnetic sensor is an example of a proximity sensor. An optical sensor, an ultrasonic sensor, or a contact sensor may be used instead of the magnetic sensor.

[0059] 10 is an explanatory diagram illustrating the relationship between the position of the piston 91 and the detection ranges of the first detection unit 61 and the second detection unit 62. Pa indicates the position of the piston 91 where the two hands 96 are at their maximum distance from each other. The state where the hands 96 are at their maximum distance from each other is included in the non-grasping state. The position of the piston 91 and the posture of the hands 96 at position Pa are, for example, the positions and postures shown in FIG. 7.

[0060] Pb indicates the gripping reference position of the piston 91 in which the hand 96 grips the tool 50 with no chips between the tool 50 and the hand 96. The state in which the hand 96 grips the tool 50 with no chips present is included in the gripping state. The position of the piston 91 and the posture of the hand 96 at position Pb are, for example, the positions and postures shown in FIG. 8 .

[0061] Pc indicates the position of the piston 91 where the two hands 96 are closest to each other. The state where the two hands 96 are closest to each other is included in the abnormal state. The position of the piston 91 and the posture of the hands 96 at position Pc are, for example, the positions and postures shown in FIG. 9 .

[0062] The distance between positions Pa and Pc is the stroke width of the piston 91 in the cylinder 90. In the stroke width, position Pa is located at the frontmost position, and position Pc is located at the rearmost position.

[0063] D1 is the maximum width at which the first detection section 61 can detect the piston 91. The maximum width D1 comprises a main detection width d1 that is not affected by environmental factors, such as temperature, and a sub-detection width k1 that is affected by environmental factors. The sub-detection width k1 is located at both ends of the maximum width D1. The sub-detection width k1 is a width that changes, for example, due to temperature changes. As the temperature decreases, the sub-detection width k1 becomes longer, and as the temperature increases, the sub-detection width k1 becomes shorter. The maximum width D1 corresponds to the first detection range.

[0064] Pd is the frontmost position of the maximum width D1 and is located between positions Pa and Pb. The front end position of the main detection width d1 is a position rearward of position Pd by the sub-detection width k1. The rearmost position of the maximum width D1 is Pe. The rear end position of the main detection width d1 is position Pb. In other words, the width between positions Pb and Pe is the sub-detection width k1.

[0065] D2 is the maximum width at which the piston 91 can be detected by the second detection section 62. The maximum width D2 comprises a main detection width d2 that is not affected by environmental factors, such as temperature, and two sub-detection widths k2 that are affected by environmental factors. The sub-detection widths k2 are located at both ends of the maximum width D2. The main detection width d1 and the main detection width d2 are approximately the same distance apart. The sub-detection width k2 and the sub-detection width k1 are approximately the same distance apart. The relationship between the sub-detection width k2 and temperature is the same as that between the sub-detection width k1. The maximum width D2 corresponds to the second detection width.

[0066] Pf is the frontmost position of maximum width D2 and is located forward of position Pa. Pg is the rearmost position of maximum width D2 and is located between positions Pd and Pb. The distance between positions Pd and Pg is longer than the secondary detection widths k1 and k2. Between positions Pd and Pg, the front end portion of maximum width D1 overlaps with the rear end portion of maximum width D2. Furthermore, maximum width D2 includes the rear secondary detection width k2, and maximum width D1 includes the front secondary detection width k1. Ph is the rear end position of main detection width d2 and is located between positions Pd and Pg.

[0067] Position Pa is located approximately in the center of maximum width D2. Since the piston 91 does not move before position Pa, the portion of maximum width D2 in front of position Pa is not used for detecting the piston 91.

[0068] When the piston 91 is between positions Pa and Pg, the second detection unit 62 detects the piston 91. When the piston 91 is between positions Pd and Pe, the first detection unit 61 detects the piston 91.

[0069] When the piston 91 is between positions Pa and Pd, i.e., in range R1, the second detection unit 62 detects the piston 91, but the first detection unit 61 does not detect the piston 91. When the piston 91 is in range R1, the hand 96 is in a non-grasping state. Range R1 corresponds to the second range.

[0070] When the piston 91 is between positions Pe and Pg, i.e., in range R3, the first detection unit 61 detects the piston 91, but the second detection unit 62 does not detect the piston 91. When the piston 91 is in range R3, the hand 96 is in a gripping state. Range R3 corresponds to the first range.

[0071] As described above, position Pb is the gripping reference position of the piston 91 where the hand 96 grips the tool 50 when there are no chips. Even if the two hands 96 are slightly closer to each other than the gripping reference position Pb, there is no problem in determining that the hand 96 is in a gripping state. Even if chips are caught between the hand 96 and the tool 50, the hand 96 can still grip the tool 50, so there is no problem in determining that the hand 96 is in a gripping state. Therefore, when the piston 91 is in the range R3 between position Pe behind the gripping reference position Pb and position Pg ahead of the gripping reference position Pb, it can be determined that the hand 96 is in a gripping state.

[0072] When the piston 91 is between the position Pe and the position Pc, that is, in the range R4, the first detection unit 61 and the second detection unit 62 do not detect the piston 91. When the piston 91 is in the range R4, the hand 96 is in an abnormal state.

[0073] When the piston 91 is between positions Pd and Pg, i.e., in range R2, the first detection unit 61 and the second detection unit 62 detect the piston 91. When the piston 91 is in range R2, the hand 96 is in a state that is neither a gripping state, a non-gripping state, nor an abnormal state, i.e., a transient state.

[0074] 11 is a table showing the relationship between the range in which the piston 91 is located, the detection results of the first detection unit 61 and the second detection unit 62, and the state of the hand 96. In Fig. 11, the case in which the first detection unit 61 and the second detection unit 62 detect the piston 91 is displayed as "ON", and the case in which the first detection unit 61 and the second detection unit 62 do not detect the piston 91 is displayed as "OFF".

[0075] 11 , when the first detection unit 61 is off and the second detection unit 62 is on, it can be determined that the hand 96 is in a non-grasping state. When the first detection unit 61 is on and the second detection unit 62 is off, it can be determined that the hand 96 is in a gripping state. When the first detection unit 61 and the second detection unit 62 are off, it can be determined that the hand 96 is in an abnormal state.

[0076] That is, taking into consideration the stroke distance of the piston 91 and the detection widths of the first detection unit 61 and the second detection unit 62, the first detection unit 61 and the second detection unit 62 are arranged in the cylinder 90 so that when the hand 96 is in a non-gripping state, the first detection unit 61 is turned off and the second detection unit 62 is turned on, when the hand 96 is in a gripping state, the first detection unit 61 is turned on and the second detection unit 62 is turned off, and when the hand 96 is in an abnormal state, the first detection unit 61 and the second detection unit 62 are turned off.

[0077] When the first detection unit 61 and the second detection unit 62 are on, it can be determined that the hand 96 is in a transitional state, changing from a gripping state to a non-gripping state or from a non-gripping state to a gripping state. The time during which the hand 96 is in the transitional state is short, and the hand 96 usually immediately changes to the gripping state or the non-gripping state.

[0078] In the machine tool according to the embodiment, it is determined whether the hand 96 is in an abnormal state different from the gripping state and the non-gripping state based on the detection results of the first detection unit 61 and the second detection unit 62. In other words, three states can be detected by two detection units, which makes it possible to suppress an increase in the number of detection units.

[0079] Furthermore, if the first detection unit 61 detects that it is off, i.e., not in a gripping state, and the second detection unit 62 detects that it is off, i.e., not in a non-gripping state, it determines that the hand 96 is in an abnormal state.

[0080] Furthermore, whether the hand 96 is in a gripping state is detected based on whether the piston 91 is in range R3. Whether the hand 96 is in a non-gripping state is detected based on whether the piston 91 is in range R1. Furthermore, a proximity sensor is used to determine whether the piston 91 is in range R1 or R3.

[0081] The transfer of the tools 50 between the first magazine 6 and the second magazine 80 will be described.

[0082] 12 shows a state in which the pod 9f is disposed at position A, the exchange position arm 84 of the second magazine 80 holds the tool 50, the exchange position arm 6c of the first magazine 6 does not hold the tool 50, and the pod 9f does not hold the tool 50. The pod 9f is positioned closer to the support disk 81 than the exchange position arm 84.

[0083] 13 shows a state in which the pod 9f is placed at position B, the exchange position arm 84 of the second magazine 80 holds the tool 50, and the exchange position arm 6c of the first magazine 6 does not hold the tool 50. The pod 9f receives the tool 50 from the exchange position arm 84 and holds it.

[0084] 14 shows a state in which the pod 9f is placed at position C, the exchange position arm 84 of the second magazine 80 does not hold the tool 50, and the pod 9f holds the tool 50. The pod 9f hands over the tool 50 to the exchange position arm 84. The exchange position arm 6c receives the tool 50 from the pod 9f and holds it.

[0085] 15 is a flowchart illustrating the process of transferring the tools 50 from the second magazine 80 to the first magazine 6 by the control device 60. In the initial state, the pod 9f is placed at position A (see FIG. 12). Hereinafter, a command to put the two hands 96 into the gripping state will also be referred to as a pod close command, and a command to put the two hands 96 into the non-gripping state will also be referred to as a pod open command.

[0086] The control unit 60a outputs a pod open command to the solenoid valve 63 (S11). The control unit 60a determines whether the detection result of the first detection unit 61 is ON (S12). If the detection result of the first detection unit 61 is ON (S12: YES), the two hands 96 are not in a non-gripping state, so the control unit 60a activates the notification unit 64 (S26) and ends the process.

[0087] If the detection result of the first detector 61 is not ON (S12: NO), the control unit 60a determines whether the detection result of the second detector 62 is ON (S13). If it is determined that the detection result of the second detector 62 is not ON (S13: NO), the two hands 96 are not in a non-grasping state, so the control unit 60a drives the notification unit 64 (S26) and ends the process.

[0088] If it is determined that the detection result of the second detection unit 62 is ON (S13: YES), the two hands 96 are in a non-grasping state, and the control unit 60a outputs a drive command to the motor 9a to move the pod 9f forward from position A to position B (S14). The motor 9a is equipped with an encoder (not shown), and the control unit 60a obtains the detection result of the encoder, i.e., the position of the pod 9f. The control unit 60a determines whether there is a change in the detection results of the first detection unit 61 and the second detection unit 62 until the pod 9f reaches position B (S15). If it is determined that there is a change in the detection results of the first detection unit 61 and the second detection unit 62 (S15: NO), that is, if there is a possibility that the two hands 96 are not maintaining a non-grasping state, the control unit 60a drives the notification unit 64 (S26) and ends the process.

[0089] If it is determined that there is no change in the detection results of the first detection unit 61 and the second detection unit 62 (S15: YES), i.e., if the two hands 96 have maintained a non-gripping state up to position B, the control unit 60a outputs a pod close command to the solenoid valve 63 (S16). The control unit 60a determines whether the detection result of the first detection unit 61 is ON (S17). If it is determined that the detection result of the first detection unit 61 is not ON (S17: NO), i.e., if the two hands 96 are not in a gripping state and have not received a tool 50 from the exchange position arm 84, the control unit 60a drives the notification unit 64 (S26) and ends the process.

[0090] If the control unit 60a determines that the detection result of the first detection unit 61 is ON (S17: YES), the control unit 60a determines whether the detection result of the second detection unit 62 is OFF (S18). If the control unit 60a determines that the detection result of the second detection unit 62 is not OFF (S18: NO), that is, if there is a possibility that the two hands 96 are stopped in a transient state, the control unit 60a drives the notification unit 64 (S26) and ends the process.

[0091] If it is determined that the detection result of the second detection unit 62 is OFF (S18: YES), i.e., if the two hands 96 have received the tool 50 from the exchange position arm 84 (see FIG. 13 ), the control unit 60a outputs a drive command to the motor 9a to move the pod 9f forward from position B to position C (S19). The control unit 60a acquires the detection result of the encoder, i.e., the position of the pod 9f, and determines whether there is a change in the detection results of the first detection unit 61 and the second detection unit 62 until the pod 9f reaches position C (S20). If it is determined that there is a change in the detection results of the first detection unit 61 and the second detection unit 62 (S20: NO), i.e., if there is a possibility that the two hands 96 are not maintaining a gripping state, the control unit 60a drives the notification unit 64 (S26) and ends the process.

[0092] If it is determined that there is no change in the detection results of the first detection unit 61 and the second detection unit 62 (S20: YES), that is, if the two hands 96 have maintained the gripping state up to position C and the tool 50 has been handed over from the hands 96 to the exchange position arm 6c (see FIG. 14), the control unit 60a outputs a pod open command to the solenoid valve 63 (S21). The control unit 60a determines whether the detection result of the first detection unit 61 is on (S22).

[0093] If it is determined that the detection result of the first detection unit 61 is ON (S22: YES), the two hands 96 are not in a non-grasping state, so the control unit 60a drives the alarm unit 64 (S26) and ends the process. If it is determined that the detection result of the first detection unit 61 is not ON (S22: NO), the control unit 60a determines whether the detection result of the second detection unit 62 is ON (S23). If it is determined that the detection result of the second detection unit 62 is not ON (S23: NO), that is, if there is a possibility that the two hands 96 are in an abnormal state, the control unit 60a drives the alarm unit 64 (S26) and ends the process.

[0094] If it is determined that the detection result of the second detection unit 62 is ON (S23: YES), that is, if the two hands 96 are in a non-gripping state and the transfer of the tool 50 from the exchange position arm 84 to the exchange position arm 6c is completed, the control unit 60a outputs a drive command to the motor 9a to move the pod 9f backward from position C to position A (S24). The control unit 60a obtains the detection result of the encoder, that is, the position of the pod 9f, and determines whether there is any change in the detection results of the first detection unit 61 and the second detection unit 62 until the pod 9f reaches position A (S25).

[0095] If it is determined that there is a change in the detection results of the first detection unit 61 and the second detection unit 62 (S25: NO), that is, if there is a possibility that the two hands 96 are not maintaining a non-grasping state, the control unit 60a drives the notification unit 64 (S26) and ends the process. If it is determined that there is no change in the detection results of the first detection unit 61 and the second detection unit 62 (S25: YES), that is, if the two hands 96 are maintaining a non-grasping state up to position A, the control unit 60a ends the process.

[0096] 16 is a flowchart illustrating the process of transferring the tool 50 from the first magazine 6 to the second magazine 80 by the control device 60. In the initial state, the pod 9f is placed at position A. The exchange position arm 84 of the second magazine 80 does not hold the tool 50. The exchange position arm 6c holds the tool 50.

[0097] The control unit 60a outputs a pod open command to the solenoid valve 63 (S31). The control unit 60a determines whether the detection result of the first detection unit 61 is ON (S32). If the detection result of the first detection unit 61 is ON (S32: YES), the two hands 96 are not in a non-gripping state, so the control unit 60a activates the notification unit 64 (S46) and ends the process.

[0098] If the detection result of the first detector 61 is not ON (S32: NO), the control unit 60a determines whether the detection result of the second detector 62 is ON (S33). If it is determined that the detection result of the second detector 62 is not ON (S33: NO), the two hands 96 are not in a non-grasping state, so the control unit 60a drives the notification unit 64 (S46) and ends the process.

[0099] If it is determined that the detection result of the second detection unit 62 is ON (S33: YES), the two hands 96 are in a non-gripping state, and the control unit 60a outputs a drive command to the motor 9a to move the pod 9f forward from position A to position C (S34). The control unit 60a acquires the detection result of the encoder, i.e., the position of the pod 9f, and determines whether there is a change in the detection results of the first detection unit 61 and the second detection unit 62 until the pod 9f reaches position C (S35). If it is determined that there is a change in the detection results of the first detection unit 61 and the second detection unit 62 (S35: NO), that is, if there is a possibility that the two hands 96 are not maintaining a non-gripping state, the control unit 60a drives the notification unit 64 (S46) and ends the process.

[0100] If it is determined that there is no change in the detection results of the first detection unit 61 and the second detection unit 62 (YES in S35), i.e., if the two hands 96 have maintained the non-gripping state up to position C, the control unit 60a outputs a pod close command to the solenoid valve 63 (S36). The control unit 60a determines whether the detection result of the first detection unit 61 is ON (S37). If it is determined that the detection result of the first detection unit 61 is not ON (NO in S37), i.e., if the two hands 96 are not in the gripping state and have not received the tool 50 from the exchange position arm 6c, the control unit 60a drives the notification unit 64 (S46) and ends the process.

[0101] If the control unit 60a determines that the detection result of the first detection unit 61 is ON (S37: YES), the control unit 60a determines whether the detection result of the second detection unit 62 is OFF (S38). If the control unit 60a determines that the detection result of the second detection unit 62 is not OFF (S38: NO), that is, if there is a possibility that the two hands 96 are stopped in a transient state, the control unit 60a drives the notification unit 64 (S46) and ends the process.

[0102] If it is determined that the detection result of the second detection unit 62 is OFF (YES in S38), i.e., if the two hands 96 have received the tool 50 from the exchange position arm 6c (see FIG. 14), the control unit 60a outputs a drive command to the motor 9a to move the pod 9f backward from position C to position B (S39). The control unit 60a acquires the detection result of the encoder, i.e., the position of the pod 9f, and determines whether there is a change in the detection results of the first detection unit 61 and the second detection unit 62 until the pod 9f reaches position B (S40). If it is determined that there is a change in the detection results of the first detection unit 61 and the second detection unit 62 (NO in S40), i.e., if there is a possibility that the two hands 96 are not maintaining a gripping state, the control unit 60a drives the notification unit 64 (S46) and ends the process.

[0103] If it is determined that there is no change in the detection results of the first detection unit 61 and the second detection unit 62 (S40: YES), that is, if the two hands 96 have maintained the gripping state up to position B and the tool 50 has been handed over from the pod 9f to the exchange position arm 84 (see FIG. 13), the control unit 60a outputs a pod open command to the solenoid valve 63 (S41). The control unit 60a determines whether the detection result of the first detection unit 61 is on or not (S42).

[0104] If it is determined that the detection result of the first detection unit 61 is ON (S42: YES), the two hands 96 are not in a non-grasping state, so the control unit 60a drives the alarm unit 64 (S46) and ends the process. If it is determined that the detection result of the first detection unit 61 is not ON (S42: NO), the control unit 60a determines whether the detection result of the second detection unit 62 is ON (S43). If it is determined that the detection result of the second detection unit 62 is not ON (S43: NO), that is, if there is a possibility that the two hands 96 are in an abnormal state, the control unit 60a drives the alarm unit 64 (S46) and ends the process.

[0105] If it is determined that the detection result of the second detection unit 62 is ON (S43: YES), that is, if the two hands 96 are in a non-gripping state and the transport of the tool 50 from the changing position arm 6c to the changing position arm 84 is completed, the control unit 60a outputs a drive command to the motor 9a to move the pod 9f backward from position B to position A (S44). The control unit 60a obtains the detection result of the encoder, that is, the position of the pod 9f, and determines whether there is any change in the detection results of the first detection unit 61 and the second detection unit 62 until the pod 9f reaches position A (S45).

[0106] If it is determined that there is a change in the detection results of the first detection unit 61 and the second detection unit 62 (S45: NO), i.e., if there is a possibility that the two hands 96 are not maintaining a non-grasping state, the control unit 60a drives the notification unit 64 (S46) and ends the process. If it is determined that there is no change in the detection results of the first detection unit 61 and the second detection unit 62 (S45: YES), i.e., if the two hands 96 are maintaining a non-grasping state up to position A, the control unit 60a ends the process. The control unit 60a that makes the determinations of YES in S12, NO in S13, NO in S17, NO in S18, NO in S20, YES in S22, NO in S23, and NO in S25 corresponds to the determination unit. The control unit 60a that executes S26 corresponds to the notification unit.

[0107] The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present disclosure is intended to include all modifications within the scope of the claims and the scope equivalent to the claims. The matters described in each embodiment can be mutually combined. Furthermore, independent claims and dependent claims described in the claims can be mutually combined in any and all combinations, regardless of the reference format. Furthermore, although the claims use a format in which a claim references two or more other claims (multiple claim format), this is not limiting. A multiple claim (multi-multi claim) format in which at least one multiple claim is referenced may also be used.

[0108] 9 Tool transport device 9f Pod 90 Cylinder 91 Piston (moving part) 92 Rod 96 Hand (holding part) 60 Control device 60a Control part 61 First detection part 62 Second detection part 63 Solenoid valve 64 Notification part

Claims

1. A tool transport device comprising: a gripping unit that can be in a gripping state in which it grips a tool or in a non-gripping state in which it does not grip the tool; a first detection unit that detects whether the gripping unit is in the gripping state; a second detection unit that detects whether the gripping unit is in the non-gripping state; and a determination unit that determines whether the gripping unit is in an abnormal state different from the gripping state and the non-gripping state based on the detection results of the first detection unit and the second detection unit.

2. A tool transport device as described in claim 1, wherein when the first detection unit detects that the tool is not in the gripping state and the second detection unit detects that the tool is not in the non-gripping state, the judgment unit judges that the gripping unit is in the abnormal state.

3. A tool transport device according to claim 1 or 2, further comprising a moving unit that moves the gripping unit, and when the position of the moving unit is within a first range, the first detection unit detects that the gripping unit is in the gripping state.

4. The tool transport device according to claim 3, wherein the second detection unit detects that the gripping unit is not in the non-gripping state when the position of the moving unit is in a second range different from the first range.

5. The tool transport device according to claim 3, wherein the first detection unit comprises a proximity sensor.

6. The tool transport device according to claim 4, wherein the second detection unit comprises a proximity sensor.

7. A tool transport device according to claim 1 or 2, further comprising a notification unit that notifies the user of the abnormal state when the determination unit determines that the gripping unit is in the abnormal state.

8. A tool transport device comprising: a gripping unit that can be in a gripping state in which it grips a tool or in a non-gripping state in which it does not grip the tool; a moving unit that moves the gripping unit; a first detection unit that detects whether the moving unit is in a first detection range; a second detection unit that detects whether the moving unit is in a second detection range different from the first detection range; and a determination unit that determines whether the gripping unit is in an abnormal state different from the gripping state and the non-gripping state based on detection results of the first detection unit and the second detection unit.

9. A machine tool comprising: a spindle to which a tool is attached; a gripping unit that can be in a gripping state in which it grips the tool or in a non-gripping state in which it does not grip the tool; a first detection unit that detects whether the gripping unit is in the gripping state; a second detection unit that detects whether the gripping unit is in the non-gripping state; and a determination unit that determines whether the gripping unit is in an abnormal state different from the gripping state and the non-gripping state based on the detection results of the first detection unit and the second detection unit.

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