Pallet replacement device

Abstract

To provide a pallet replacement device with which scattering of coolant at the time of pallet replacement is reduced while suppressing an increase in turning type pallet replacement time as much as possible.SOLUTION: A pallet replacement device 130 of a machine tool that replaces a pallet by using a turning arm includes: a turning drive device 138 capable of switching a turning command speed to a different value during turning of a turning arm 132; a graphical user interface screen 200 that sets a phase of switching the turning command speed of the turning arm; and a control device 150 that switches the turning command speed of the turning drive device 138 according to a phase set in the graphical user interface screen.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a pallet changer used together with a machine tool or a workpiece cleaning device.

Background Art

[0002] There are various types of pallet changers for exchanging a pallet with a processed workpiece attached thereto and a pallet with an unprocessed workpiece attached thereto. Among them, a type of pallet changer is widely used in which a pallet with a processed workpiece attached thereto is placed on one end of a swing arm, a pallet with an unprocessed workpiece attached thereto is placed on the other end, and the swing arm is rotated 180° around a vertical axis to exchange the pallets.

[0003] In order to increase the productivity of a machine tool, it is preferable that the time required for pallet exchange is short. However, the speed of pallet exchange is restricted by the driving force required for the rotation of the swing arm and the centrifugal force that prevents the pallet and the workpiece from tipping over, and it is generally fixed at a single speed calculated from these restrictions. Patent Document 1 describes a pallet changer in such a pallet changer that measures the weight of various workpieces using a strain gauge and changes the swing speed during various pallet movements according to the weight of each workpiece, thereby shortening the pallet exchange time.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a pallet changer equipped with such a swivel arm, during the pallet changing operation, as the swivel arm rotates, the coolant adhering to the members that rotate together with the swivel arm, such as the machined workpiece, the pallet, and the swivel door, scatters. Since the scattered coolant contaminates the surroundings of the pallet changer, it may be important to prevent the scattering of the coolant. However, in the pallet changer of Patent Document 1, when the workpiece is light, the swivel arm rotates at high speed, so a large amount of coolant is scattered over a wide area around the pallet changer. On the other hand, if the swivel arm is rotated at a low speed, the scattering of the coolant can be suppressed, but there is a problem that the pallet changing time becomes long and the productivity of the machine decreases.

[0006] An object of the present invention is to solve such problems of the prior art, and to provide a pallet changer that reduces the scattering of coolant during pallet changing without increasing the swivel type pallet changing time as much as possible.

Means for Solving the Problems

[0007] In order to solve the above problems, according to the present invention, in a pallet changer of a machine tool that exchanges a pallet using a swivel arm, during the rotation of the swivel arm, a swivel drive device capable of switching the swivel command speed to different values, a phase setting device for setting a phase for switching the swivel command speed of the swivel arm, and a control device for switching the swivel command speed of the swivel drive device according to the phase set by the phase setting device are provided.

Effects of the Invention

[0008] According to the present invention, since the swivel command speed is switched at the phase set by the phase setting device, the section where the scattering of the coolant can be prevented by rotating the swivel arm at a low speed is limited, and it is possible to effectively suppress the scattering of the coolant without significantly increasing the pallet changing time.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0010] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Referring to FIGS. 1 and 2 showing an example of a machine tool to which the present invention is applied, the machine tool 100 includes a bed 102 as a base fixed to the floor surface of the factory. On the upper surface of the front portion (the left side in FIGS. 1 and 2) of the bed 102, a Z-axis slider 112 is provided so as to be reciprocable along a pair of Z-axis guide rails 102b extending in the front-rear direction or the Z-axis direction (the left-right direction in FIGS. 1 and 2). A rotary table 114 is provided on the Z-axis slider 112 so as to be rotationally feedable in the B-axis direction about a vertical axis. The rotary table 114 includes a B-axis servo motor (not shown) as a B-axis feed device for rotationally feeding the rotary table 114 in the B-axis direction.

[0011] On the upper surface of the rear portion of the bed 102 (the right side in FIGS. 1 and 2), a column 104 is provided so as to be reciprocally movable along a pair of X-axis guide rails 102a extending in the left-right direction or the X-axis direction (the direction perpendicular to the paper surface in FIG. 1, the up-down direction in FIG. 2). On the front surface of the column 104, a Y-axis slider 106 is provided so as to be reciprocally movable along a Y-axis guide rail (not shown) extending in the up-down direction or the Y-axis direction. A spindle head 108 that rotatably supports a spindle 110 about a horizontal central axis O is attached to the Y-axis slider 106. A spindle servo motor (not shown) for rotationally driving the spindle 110 is disposed on the spindle head 108.

[0012] A pallet P to which a work fixture M such as an IKE is attached is detachably fixed to the rotary table 114. In the present embodiment, when the work fixture M is fixed to the rotary table 114 together with the pallet P, it has a work mounting surface perpendicular to the Z-axis, and a work W is mounted on the work mounting surface. In this way, the work W to be machined is mounted so as to face the tool T attached to the tip of the spindle 110. Note that the work W may be directly fixed to the pallet P without using a work fixture M such as an IKE.

[0013] Furthermore, in the machine tool 100, an X-axis servo motor (not shown) as an X-axis feed device for driving the column 104 in the X-axis direction and a Z-axis servo motor (not shown) as a Z-axis feed device for driving the Z-axis slider 112 in the Z-axis direction are disposed on the bed 102. A Y-axis servo motor (not shown) as a Y-axis feed device for driving the Y-axis slider 106 in the Y-axis direction is disposed on the column 104. In this way, by the X-axis feed device, the Y-axis feed device, and the Z-axis feed device, the spindle 110 and the rotary table 114 are relatively linearly fed in three orthogonal axis directions.

[0014] Further, the machine tool according to the present embodiment includes a tool magazine 140 that stores a plurality of tools necessary for machining in the machine tool 100, one of the tools stored in the tool magazine 140, and an automatic tool changer 142 that exchanges the tool T mounted on the tip of the spindle 110 of the machine tool 100, and a control device 150 that controls the machine tool 100.

[0015] Furthermore, the machine tool 100 according to the present embodiment includes a pallet changer 130 disposed in front of the rotary table 114 on the upper surface of the bed 102. The pallet changer 130 includes a swivel shaft 134 rotatably provided about a vertical swivel axis OV, a swivel arm 132 extending horizontally and attached to the upper end of the swivel shaft 134, a swivel door 122 attached to the upper end of the swivel shaft 134 and extending in a vertical plane, a swivel drive device that rotates the swivel shaft 134 about the swivel axis OV, and a swivel arm lifting device that raises and lowers the swivel arm 132.

[0016] In the present embodiment, the swivel drive device includes a pallet change servo motor 138 rotatable about the swivel axis OV and a rotary encoder 138a that measures the rotational position (phase) of the pallet change servo motor 138. Further, the swivel arm lifting device includes a lifting servo motor 144, a ball screw 146 directly connected to the output shaft of the lifting servo motor 144, and a ball screw nut 148 attached to the lower end of the swivel arm 132.

[0017] The main components including the Z-axis slider 112, the rotary table 114, and the spindle 110 of the machine tool 100, the automatic tool changer 142, and the pallet changer 130 are surrounded by a splash guard 120. Also, as shown in FIGS. 1 and 2, when the swing door 122 is in a rotational position perpendicular to the Z-axis of the machine tool 100, the space within the splash guard 120 is divided into a machining chamber 126 where one end (the end indicated by reference numeral 132b in FIGS. 1 and 2) of the swing arm 132 of the Z-axis slider 112, the rotary table 114, the spindle 110, and the pallet changer 130 of the machine tool 100 is arranged, and a workpiece setup chamber 128 where the other end (the end indicated by reference numeral 132a in FIGS. 1 and 2) of the swing arm 132 is arranged.

[0018] For the operator to access the workpiece setup chamber 128, the splash guard 120 has a workpiece setup chamber opening 120a and a workpiece setup chamber safety door 124 that opens and closes the workpiece setup chamber opening 120a. The workpiece setup chamber safety door 124 is provided with a window for the operator to visually observe the interior of the workpiece setup chamber 128. The machine tool 100 includes a workpiece setup chamber side operation panel 136 for operating the machine tool 100. The workpiece setup chamber side operation panel 136 includes a display device, a keyboard (not shown) and / or buttons (not shown) for inputting numerical values and commands to the control device 150, and further includes a display device (not shown) for displaying the state of the machine tool 100 and for the operator to confirm the numerical values input. The display device can be formed by a touch panel (not shown). Similarly, the machining chamber 126 includes a machining chamber opening 120b, a machining chamber operator door 125 that opens and closes the machining chamber opening 120b, and a machining chamber side operation panel 137 for operating the machine tool 100.

[0019] The control device 150 can be composed of a computer including a CPU (Central Processing Unit), a memory device such as a RAM (Random Access Memory) and a ROM (Read Only Memory), a storage device such as an HDD (Hard Disk Drive) and an SSD (Solid State Drive), an input / output port, an RTC (Real-Time-Clock), and a bidirectional bus for interconnecting these, and related software. The control device 150 can be configured software-wise as part of a machine control device (not shown) that controls, in particular, the tool magazine 140, the automatic tool changer 142, and the pallet changer 130. The control device 150 may include an NC device 156 (see FIG. 3) that controls the spindle servo motor, the X-axis servo motor, the Y-axis servo motor, the Z-axis servo motor, and the B-axis servo motor.

[0020] Referring to FIG. 3, a block diagram of a turning drive device for the pallet changer 130 according to one embodiment is shown. The turning drive device according to this embodiment includes a rotary encoder 138a that detects the phase or rotation angle of the turning arm 132, the turning shaft 134, and the pallet change servo motor 138, a turning servo amplifier 152 that supplies drive current to the pallet change servo motor 138 based on a control signal from the control device 150, a lifting servo amplifier 158 that supplies drive power to the lifting servo motor 144 based on a control signal from the control device 150, and an input device 154 that inputs parameters described later to the control device 150.

[0021] The operation of this embodiment will be described below. When the machining of the workpiece W is completed, the pallet is exchanged. The pallet exchange includes: 1) a first stage of moving the pallet P on which the machined workpiece is mounted to the pallet exchange position; 2) a second stage of raising the turning arm 132 to place the pallet; 3) a third stage of turning the turning arm 132; and 4) a fourth stage of lowering the turning arm 132 to place the pallet on the rotary table 114.

[0022] First, in the first stage, the pallet P to which the processed workpiece W is attached moves in the Z-axis direction toward the pallet changer 130 and stops at the pallet change waiting position. At this time, the first end portion 132b extending into the processing chamber 126 of the swing arm 132 of the pallet changer 130 enters between the pallet P and the rotary table 114.

[0023] Next, shifting to the second stage, after the NC device 156 confirms that the rotary table 114 is arranged at the pallet change waiting position, it outputs a pallet change command to the control device 150. Upon receiving the pallet change command, the control device 150 outputs a control command to the lifting servo amplifier 158 according to the held pallet change program. The lifting servo amplifier 158 outputs current to the lifting servo motor 144 based on the control command from the control device 150. Thereby, the lifting servo motor 144 and the ball screw 146 directly connected to the output shaft of the lifting servo motor 144 rotate, and the ball screw nut 148 attached to the lower end of the swing arm 132 moves upward.

[0024] Thereby, the swing arm 132 rises together with the swing door 122. Also, the pallet P is lifted from the rotary table 114 by the first end portion 132b extending into the processing chamber 126 of the swing arm 132. When the pallet P is placed on the swing arm, the rotary table 114 moves in a direction away from the swing arm 132 along the Z-axis to a retracted position where it does not interfere with the swing arm 132 according to the command of the NC device 156. Thereby, the second stage of the pallet change ends.

[0025] Next, shifting to the third stage, the swing servo amplifier 152 outputs current to the pallet change servo motor 138 based on the control command from the control device 150. Thereby, the pallet change servo motor 138 rotates about the swing axis OV, and the swing arm 132 and the swing door 122 swing 180° about the swing axis OV together with the swing shaft 134. When the swing of the swing arm 132 is completed, the third stage ends.

[0026] Next, moving on to the fourth stage, the NC device 156 moves the rotary table 114 along the Z-axis from the retracted position to the pallet exchange standby position, and then rotates the elevating servo motor 144 so that the swing arm 132 descends. As a result, the pallet placed on the second end portion 132a of the swing arm 132 is placed on the rotary table 114, and the fourth stage of the pallet exchange is completed. At this time, the processed workpiece W in the processing chamber 126 is placed in the workpiece setup chamber 128, and the unprocessed workpiece W prepared in the workpiece setup chamber 128 is placed in the processing chamber 126. In this way, the unprocessed workpiece and the processed workpiece are exchanged.

[0027] With the pallet exchange operation, the coolant adhering to the members that rotate together with the swing arm 132 such as the pallet P, the workpiece fixture M, the workpiece W, and the swing door 122 scatters into the workpiece setup chamber 128 due to centrifugal force and adheres to the window of the workpiece setup chamber safety door 124, which hinders the operator's observation of the inside of the workpiece setup chamber 128. To solve this problem, in the present embodiment, the swing command speed is changed during a part of the swing process of the swing arm 132 and the swing door 122, that is, during a certain section in the third stage of the pallet exchange operation.

[0028] Referring to FIG. 4, a graph showing the speed change of the swing operation of the swing arm 132 in the pallet exchange process is shown. In the graph of FIG. 4, the vertical axis represents the swing command speed (rpm) of the swing arm 132. The horizontal axis represents the time (seconds) in one pallet exchange process, and the start time of the pallet exchange process is T = 0. The swing arm accelerates from the speed of 0 at T = 0 to the swing command speed, maintains the swing command speed substantially throughout the pallet exchange, and decelerates from the swing command speed to the speed of 0 as the swing end position approaches.

[0029] In FIG. 4, line L1 shows the change in the turning speed during the normal pallet exchange operation in which the turning arm 132 and the turning door 122 are turned at a turning command speed V1 (hereinafter referred to as the high turning command speed) substantially throughout the pallet exchange process. Generally, since it is preferable that the time required for pallet exchange is shorter as described above, the high turning command speed V1 is set based on the speed at which the pallet loaded with the work does not fall due to centrifugal force during turning or the upper limit output of the turning mechanism. Line L2 shows the change in the turning speed during the conventional pallet exchange operation in which the turning arm 132 and the turning door 122 are turned at a turning command speed V2 (hereinafter referred to as the low turning command speed) lower than V1 for the purpose of preventing or reducing the scattering of the coolant. In the prior art, the turning speed is reduced from the high turning command speed V1 to the low turning command speed V2 substantially throughout the pallet exchange process. As a result, the coolant scattered by the centrifugal force during the pallet exchange operation is reduced, and the adhesion of the coolant to the window of the work setup chamber safety door 124 is prevented or reduced. However, the time required for the pallet exchange process increases from T3 to T5, and the productivity decreases.

[0030] Line L3 shows the change in the turning speed during the pallet exchange operation according to the present embodiment. In the present embodiment, after the start of the pallet exchange operation, at time T1, the turning speed is reduced from the high turning command speed V1 to the low turning command speed V2, and at time T2, the turning speed is restored from the low turning command speed V2 to the high turning command speed V1. Of course, if the position of the turning arm at time T2 is close to the turning end position and the return from the low turning command speed V2 to the high turning command speed V1 is not in time, it is also possible not to perform the return at the low turning command speed V2.

[0031] Thus, in order to reduce the turning speed of the turning arm 132 during a certain period of the pallet exchange operation, the turning speed is reduced from the high turning command speed V1 to the low turning command speed V2, and the timing to return from the low turning command speed V2 to the high turning command speed V1, as well as the degree of reduction of the turning speed, or the high turning command speed V1 and the low turning command speed V2, are input from the input device 154 to the control device 150. As will be described below, in the present embodiment, the input device 154 is formed by a touch panel which is a display device of the work setup chamber side operation panel 136.

[0032] Referring to FIG. 5, an example of the graphical user interface displayed on the touch panel is illustrated. To the touch panel as the input device 154, as parameters for the pallet exchanger 130, the low turning command speed V2, the shift start point P1 and the shift end point P2 for switching the turning speed of the turning arm 132 between the high turning command speed V1 and the low turning command speed V2 are input.

[0033] In FIG. 5, reference numeral 200 indicates a graphical user interface screen displayed on the touch panel of the work setup chamber side operation panel 136 as a display device. The graphical user interface screen 200 includes a graphic display 202 for the pallet exchanger 130 and a parameter display area 210. The graphic display 202 for the pallet exchanger 130 includes the turning arm 132, the pallet P, the turning door 204, the window 206 of the work setup chamber safety door 124, and the locus 208 drawn by the tips of the turning arm 132, the pallet P, and the turning door 204 during turning.

[0034] The parameter display area 210 includes an area 212 for displaying the phase θ1 of the shift start point P1 at which the turning speed is changed to the low turning command speed V2, an area 214 for displaying the phase θ2 of the shift end point P2 at which the turning speed is restored to the high turning command speed V1, and an area 216 for displaying the low turning command speed V2. By tapping a point on the locus 208 of the graphical user interface screen 200, the operator can automatically input the phases θ1 and θ2 from the standby position where the turning door 204 is orthogonal to the Z-axis, and set the shift start point P1 and the shift end point P2 in the control device 150.

[0035] Thus, in this embodiment, the timing for reducing the turning speed from the high turning command speed V1 to the low turning command speed V2 and then restoring it from the low turning command speed V2 to the high turning command speed V1 is set in the control device 150 by inputting the shift start point P1 and the shift end point P2 through the graphical user interface screen 200. That is, the graphical user interface screen 200 constitutes a phase setting device for setting the phases of the shift start point P1 and the shift end point P2 for switching the turning speed of the turning arm 132 between the high turning command speed V1 and the low turning command speed V2.

[0036] Note that the turning arm 132 alternately repeats the counterclockwise rotation shown in FIG. 5 and the clockwise rotation in the direction opposite to FIG. 5 each time the pallet is exchanged. During clockwise rotation, the turning speed control is performed by reading P2 as P1 and P1 as P2. Also, the phases θ1 and θ2 may be angles from, for example, the horizontal direction with respect to the Z-axis, rather than angles from the standby position orthogonal to the Z-axis. Ultimately, it is sufficient that the shift start point P1 and the shift end point P2 can be uniquely determined during pallet exchange.

[0037] Also, in the embodiment of FIG. 5, instead of directly inputting the reduced turning command speed, the low turning command speed V2 is input as a deceleration ratio δ% with respect to the high turning command speed V1. The deceleration ratio δ% can be input, for example, by the operator tapping the area 216, which then becomes active, using the keys on the work setup chamber side operation panel 136. Alternatively, when the operator taps the area 216, a dialog box (not shown) for inputting the deceleration ratio δ% may be displayed within the graphical user interface screen 200. It is also possible to directly input the decelerated low turning command speed V2. Of course, without using the graphical user interface, the high turning command speed V1, the low turning command speed V2, and the deceleration ratio δ% may be input as G-codes, M-codes, machine parameters, or NC parameters. Similar operations can also be performed using the processing chamber side operation panel 137.

[0038] In this embodiment, when the pallet exchange operation is started, the control device 150 monitors the signal from the rotary encoder 138a, and when the phase or rotation angle of the pallet exchange servo motor 138, that is, the phase or rotation angle of the turning arm 132 with respect to the turning axis OV, reaches θ1, it outputs a control command to the turning servo amplifier 152 to reduce the output current value to the current value corresponding to the low turning command speed V2. Based on the control command from the control device 150, the turning servo amplifier 152 outputs a current corresponding to the low turning command speed V2 to the pallet exchange servo motor 138. As a result, the turning speed of the pallet exchange servo motor 138 is reduced from the high turning command speed V1 to the low turning command speed V2.

[0039] The control device 150 continuously monitors the signal from the rotary encoder 138a, and when the phase or rotation angle of the swivel arm 132 reaches θ2, it outputs a control command to the swivel servo amplifier 152 to control the output current value to return to the current value corresponding to the high swivel command speed V1. The swivel servo amplifier 152 outputs a current corresponding to the high swivel command speed V1 to the pallet exchange servo motor 138 based on the control command from the control device 150. As a result, the swivel speed of the pallet exchange servo motor 138 returns from the low swivel command speed V2 to the high swivel command speed V1.

[0040] According to the present embodiment, by reducing the swivel speed in a certain section of the pallet exchange operation, it is possible to prevent or reduce the coolant scattered by the centrifugal force during the pallet exchange operation from adhering to the window of the work setup chamber safety door 124 without excessively increasing the time required for the pallet exchange. According to the present embodiment, the time required for the pallet exchange process is shortened from T5 of the prior art, in which the swivel speed is substantially reduced from the high swivel command speed V1 to the low swivel command speed V2 throughout the pallet exchange process, to T4.

[0041] In the above-described embodiment, the work setup chamber safety door 124 is provided with a window for visually observing the inside of the work setup chamber 128. However, even when a side window (not shown) provided on the side surface of the splash guard 120 or an in-machine camera (not shown) is provided inside the work setup chamber 128, it is possible to prevent the coolant from scattering to the side window or the in-machine camera.

[0042] At this time, according to the distance from the swivel door of the side window or the in-machine camera, a low swivel command speed V3 different from the low swivel command speed V2, an additional shift start point P3, and a shift end point P4 are set, and the swivel speed may be changed in three stages: the high swivel command speed V1, the low swivel command speed V2, and the low swivel command speed V3. Ultimately, the intention of the present invention is to change the speed during pallet exchange at an arbitrary point in order to suppress the scattering of the coolant without reducing the productivity as much as possible, and for this purpose, the number of changes and the change speed can be freely set.

[0043] According to this embodiment, the operator can easily change parameters at any time while observing the scattering state of the coolant during the pallet exchange operation. For example, when the workpiece W is a tall workpiece or a workpiece having a recess where coolant is likely to accumulate such as a spoon shape, the coolant is likely to scatter far, but it is difficult to predict the scattering area of the coolant in advance. Therefore, it is advantageous that the operator can change parameters, particularly the low turning command speed V2, while observing the scattering state of the coolant during the pallet exchange operation.

[0044] Although the preferred embodiments of the present invention have been described, it is a matter of course for those skilled in the art that the present invention is not limited to the above-described embodiments, and various changes and improvements are possible. In the example of FIG. 3, by using the rotary encoder 138a to detect the phase or rotation angle of the turning arm 132, when the shift start point P1 and the shift end point P2 are reached, the turning speed is reduced from the high turning command speed V1 to the low turning command speed V2, and then restored from the low turning command speed V2 to the high turning command speed V1. However, it may be configured to change the turning speed by providing a time counter and measuring the time from the start of the pallet exchange operation.

[0045] In this case, based on the shift start point P1, the shift end point P2, the high turning command speed V1, and the low turning command speed V2 input on the graphical user interface screen 200, the control device 150 can calculate in advance the time from the start of the pallet exchange until the turning arm 132 reaches the shift start point P1 and the shift end point P2 by calculation, or measure the time simultaneously with the start of the pallet exchange by a time counter, and calculate the phase or rotation angle of the turning arm by the control device 150, so that the turning speed can be reduced from the high turning command speed V1 to the low turning command speed V2 and restored from the low turning command speed V2 to the high turning command speed V1 at an appropriate timing.

[0046] In addition, in the above-described embodiment, the turning drive device includes the pallet exchange servo motor 138 which is an electric motor, but the present invention is not limited thereto. The turning drive device may include, for example, a hydraulic motor such as a hydraulic cylinder.

[0047] In the modification shown in FIG. 6, the turning drive device includes a hydraulic cylinder 160 instead of the above-described pallet exchange servo motor 138. The hydraulic cylinder 160 turns the turning shaft 134, the turning arm 132, and the turning door 122 via a rack and pinion mechanism 162. A piston (not shown) of the hydraulic cylinder 160 is coupled to a rack gear (not shown) of the rack and pinion mechanism 162, and a pinion (not shown) engaged with the rack gear is coaxially coupled to the turning shaft 134. The turning drive device further includes a hydraulic supply device 170 that supplies hydraulic pressure to the hydraulic cylinder 160 and a time counter 164. The time counter 164 may use the RTC when the control device 150 includes the RTC.

[0048] Referring to FIG. 7, the hydraulic supply device 170 shown as an example includes a hydraulic pump 172 that sucks hydraulic oil from an hydraulic oil tank 174, pressurizes it to a predetermined pressure, and supplies it to the hydraulic cylinder 160. The hydraulic supply device 170 further includes a proportional electromagnetic control valve 176 disposed between the hydraulic pump 172 and the hydraulic cylinder 160 and capable of changing the flow rate of the hydraulic pressure output by an electric signal. Further, the proportional electromagnetic control valve 176 can include, for example, a two-position or three-position direction switching valve. The hydraulic cylinder 160 extends or contracts according to the position of the direction switching valve of the proportional electromagnetic control valve 176.

[0049] When the control device 150 receives a pallet exchange command from the NC device 156, it outputs a hydraulic pressure supply command to the hydraulic pressure supply device 170 according to the pallet exchange program it holds. The hydraulic pressure supply command is the command signal voltage supplied to the proportional electromagnetic control valve 176. In the present embodiment, since the hydraulic pressure supply device 170 is provided with a proportional electromagnetic control valve 176 capable of changing the flow rate according to the command signal voltage commanded by the control device 150, the supply amount of the hydraulic oil to the hydraulic cylinder 160 per unit time can be changed. When the proportional electromagnetic control valve 176 is closed, the hydraulic oil is not supplied to the hydraulic cylinder 160 but is recovered into the hydraulic oil tank 174.

[0050] In the example of FIG. 3, by using the rotary encoder 138a to detect the phase or rotation angle of the swing arm 132, when the shift start point P1 and the shift end point P2 are reached, the swing speed is reduced from the high swing command speed V1 to the low swing command speed V2, and then restored from the low swing speed V2 to the high swing command speed V1. However, in the modification example of FIG. 6, the swing command speed is changed by measuring the time from the start of the pallet exchange operation by the time counter 164.

[0051] That is, as described above, based on the shift start point P1, the shift end point P2, the high swing command speed V1, and the low swing command speed V2 input on the graphical user interface screen 200, after the start of pallet exchange, the control device 150 can calculate by calculation the time until the phase or rotation angle of the swing arm 132 reaches the shift start point P1 and the shift end point P2, or measure the time simultaneously with the start of pallet exchange by the time counter 164, and reduce the swing speed from the high swing command speed V1 to the low swing command speed V2 and restore it from the low swing command speed V2 to the high swing command speed V1 at an appropriate timing when the control device 150 calculates the phase or rotation angle of the swing arm.

[0052] In the modification example of FIG. 6, instead of the time counter 164, a limit switch (not shown) installed in a rack and pinion mechanism or a swing arm may be used to detect that the phase or rotation angle of the swing arm 132 has reached the speed change start point P1 and the speed change end point P2.

[0053] In the above-described embodiment, the splash guard 120 has a work setup chamber opening 120a for the operator to access the work setup chamber 128, and a work setup chamber safety door 124 is provided to be openable and closable at the work setup chamber opening 120a. However, the present invention is not limited to this, and it may be applied to a machine tool used in a so-called automated machining system equipped with a pallet transfer line where the operator does not access the work setup chamber.

[0054] Referring to FIG. 8, another example of a machine tool to which the present invention is applied is shown. In FIG. 8, different from the machine tool 100, the machine tool 300 is configured such that, in principle, an operator does not access the setup chamber. The machine tool 300 includes a spindle head 304 that rotatably supports a spindle 302 around a horizontal central axis O, a table 306 provided to be movable in the Z-axis direction, a swing arm 308 provided to be rotatable together with a swing axis 312 extending in the vertical direction, and a pallet changer including a swing door 310, a splash guard 316 that surrounds the spindle 302, the spindle head 304, the table 306, the pallet changer 308, 310, 312, and a control device 350 that controls the machine tool 300.

[0055] The machine tool 300 includes a swing drive device (not shown) in the swing arm 308, the swing door 310, and the swing axis 312 as in the above-described embodiment. Further, similar to the above-described embodiment, the machine tool 300 includes a phase detection device such as a rotary encoder, a limit switch, or a time counter that detects the phase or rotation angle of the pallet changer, that is, the phase or rotation angle of the swing arm 308.

[0056] The spindle 302, spindle head 304, table 306, pallet changer 308, 310, 312, spindle 302, spindle head 304, table 306, splash guard 316 and control device 350 are configured in the same manner as in the above-described embodiments. Although not shown in FIG. 8, the machine tool 300 also includes a tool magazine and a tool changer.

[0057] The machine tool 300 includes a pallet transfer device 320. The pallet transfer device 320 includes a transfer vehicle 322 that is reciprocally movable along a rail 326 extending in the X-axis direction and a pallet transfer arm 324 that is mounted on the transfer vehicle 322 and is movable forward and backward in the Z-axis direction. The pallet transfer arm 324 can access the swing arm 308 of the pallet changer in the workpiece setup chamber 328 through the opening 316a of the splash guard 316. As described above, in this configuration, machine tools not limited to a plurality of machining centers along the rail 326, a pallet stocker for storing machined or pre-machined pallets, and a workpiece cleaning device can be arranged, and an automated machining system for transferring and delivering pallets between them by the transfer vehicle 322 can also be formed.

[0058] In this example, the splash guard 316 does not include a workpiece setup chamber safety door for opening and closing the opening 316a. In this case, in the existing form, the coolant scattered from the opening 312a contaminates the floor surface of the pallet transfer device 320. If the cut coolant is a water-soluble coolant, it will rot and cause deterioration of the factory environment such as bad smell, and if it is a water-insoluble coolant, it may also cause a fire. In order to clean this contamination manually, it is necessary to stop the transfer vehicle 322 for safety, which causes a decrease in productivity. Even in such a case, the present invention can be applied to prevent the coolant from scattering from the opening 316a to the outside of the splash guard 316 without excessively increasing the time required for pallet exchange. Also in this case, the command speed and shift points can be set using the operation panel 318 on the machining chamber side.

[0059] In the above-described embodiments, the machine tools 100 and 300 constitute horizontal machining centers, but the present invention is not limited thereto, and a vertical machining center may also be used. Furthermore, the present invention is not limited to machine tools. For example, in an automated machining system, it may be applied to a pallet changer of a cleaning device that is installed together with the machine tool 300, receives and transfers a pallet loaded with a machined workpiece to and from the pallet transfer device 320, and automatically cleans the machined workpiece.

Explanation of Signs

[0060] 100 Machine tool 112 Z-axis slider 114 Rotary table 120 Splash guard 120a Work setup chamber opening 120b Machining chamber opening 122 Swing door 124 Work setup chamber safety door 125 Machining chamber operator door 126 Machining chamber 128 Work setup chamber 130 Pallet changer 132 Swing arm 134 Swing axis 136 Work setup chamber side operation panel 137 Machining chamber side operation panel 138 Pallet exchange servo motor 138a Rotary encoder 144 Lifting servo motor 150 Control device 152 Swing servo amplifier 154 Input device 156 NC device 158 Lifting servo amplifier 160 Hydraulic cylinder 162 Rack and pinion mechanism

Claims

1. In a pallet changer for a machine tool that exchanges pallets using a swivel arm, a swivel drive device capable of switching the swivel command speed to different values during the swiveling of the swivel arm; a phase setting device for setting a phase for switching the swivel command speed of the swivel arm; a control device for switching the swivel command speed of the swivel drive device according to the phase set by the phase setting device; A pallet changer characterized by comprising the above.

2. The pallet changer according to claim 1, wherein the phase setting device is a graphical user interface displayed on a display device.

3. The phase for switching the swivel command speed includes a speed change start point for switching the swivel speed of the swivel arm from a high swivel command speed to a low swivel command speed, and a speed change end point for switching the swivel speed of the swivel arm from the low swivel command speed to the high swivel command speed. The pallet changer according to claim 1.

4. The pallet changer according to claim 2, wherein the graphical user interface includes a movement locus of the swivel arm, and an operator can indicate the speed change start point and the speed change end point on the movement locus.

5. The pallet changer according to claim 1, wherein the swivel drive device includes a servo motor for swiveling the swivel arm around a vertical axis, and a rotary encoder for detecting the rotation angle of the servo motor.

6. The swivel drive device has a servo motor for swiveling the swivel arm around a vertical axis, the phase setting device has a time counter for measuring the elapsed time from the start of pallet exchange, and the phase for switching the commanded swivel speed of the swivel arm is set by the time measured by the time counter. The pallet changer according to claim 1.

Images