Pallet exchange device

Abstract

To provide a pallet exchange device which reduces the scattering of coolant during pallet exchange without increasing the time required for exchanging a rotating pallet as much as possible. [Solution] A pallet exchange device 130 of a machine tool that exchanges pallets using a rotating arm has a rotating drive unit 138 that can switch the rotating command speed to different values ​​while the rotating arm 132 is rotating, a graphical user interface screen 200 that sets the phase for switching the rotating command speed of the rotating arm, and a control device 150 that switches the rotating command speed of the rotating drive unit 138 in accordance with the phase set on the graphical user interface screen.

Description

[Technical field]

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

[0002] There are various types of pallet exchange devices that exchange a pallet carrying a machined workpiece for a pallet carrying an unmachined workpiece, but the most widely used type of pallet exchange device involves placing a pallet carrying a machined workpiece on one end of a rotating arm, and a pallet carrying an unmachined workpiece on the other end, and rotating the rotating arm 180° about a vertical axis to exchange pallets.

[0003] In order to increase the productivity of machine tools, it is preferable to shorten the time required for pallet exchange. However, the speed of pallet exchange is limited by the driving force required to rotate the rotating arm and the centrifugal force required to prevent the pallet and workpiece from falling over, and is generally fixed at one speed calculated from these limitations. Patent Document 1 describes a pallet exchange device that uses a strain gauge to measure the weight of workpieces of various weights and changes the rotation speed during pallet movement to various values ​​according to the weight of each workpiece, thereby shortening the pallet exchange time. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-276162 A Summary of the Invention [Problem to be solved by the invention]

[0005] In such a pallet exchange device equipped with a rotating arm, the rotation of the rotating arm during a pallet exchange operation causes the coolant adhering to the components that rotate with the rotating arm, such as the machined workpiece, the pallet, and the rotating door, to scatter. Since the scattered coolant contaminates the area around the pallet exchange device, it can be important to prevent the coolant from scattering, but in the pallet exchange device of Patent Document 1, when the workpiece is light, the rotating arm rotates at high speed, scattering a large amount of coolant over a wide area around the pallet exchange device. On the other hand, rotating the rotating arm at a slow speed can prevent coolant from splashing, but it increases the time required for pallet replacement, which reduces the productivity of the machine.

[0006] The present invention has as its technical objective the resolution of these problems in the prior art, and aims to provide a pallet changing device that reduces the splashing of coolant during pallet changing without increasing the time required for rotating pallet changing as much as possible. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, according to the present invention, a pallet exchange device for a machine tool that exchanges pallets using a swing arm includes a swing drive device that can switch a swing command speed to different values ​​while the swing arm is swinging, a phase setting device that sets a phase for switching the swing command speed of the swing arm, and a control device that switches the swing command speed of the swing drive device in accordance with the phase set by the phase setting device. an input device that inputs a rotation command speed for preventing the coolant from scattering due to the rotation of the rotation arm to the control device and inputs a phase for switching the rotation command speed to the phase setting device; A pallet exchange apparatus is provided comprising: Effect of the Invention

[0008] According to the present invention, the rotation command speed is switched according to the phase set by the phase setting device, so that the section in which coolant splashing can be prevented by rotating the rotation arm at a low speed is limited, making it possible to effectively suppress coolant splashing without significantly increasing the pallet replacement time. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic side view showing an example of a machine tool to which the present invention is applied. [Diagram 2] FIG. 2 is a schematic plan view of the machine tool of FIG. [Diagram 3] FIG. 2 is a block diagram showing a rotation drive device that rotates the rotation arm. [Figure 4] 13 is a graph showing the relationship between turning speed and pallet exchange time. [Diagram 5] 4 is a schematic diagram of a graphical user interface displayed on a display device. [Figure 6] FIG. 13 is a block diagram showing another example of the turning drive device. [Figure 7] 7 is a block diagram showing an example of a hydraulic pressure supply device used in the swing drive device of FIG. 6. [Figure 8] FIG. 11 is a schematic plan view showing another example of a machine tool to which the present invention is applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. 1 and 2 showing an example of a machine tool to which the present invention is applied, machine tool 100 is equipped with a bed 102 as a base fixed to the floor of a factory. On the upper surface of the front part (left side in Figs. 1 and 2) of bed 102, a Z-axis slider 112 is provided so as to be capable of reciprocating along a pair of Z-axis guide rails 102b extending in the front-rear direction or the Z-axis direction (left-right direction in Figs. 1 and 2). On Z-axis slider 112, a rotary table 114 is provided so as to be rotatably fed in the B-axis direction around a vertical axis. Rotary table 114 is equipped with a B-axis servo motor (not shown) as a B-axis feed device that rotates and feeds rotary table 114 in the B-axis direction.

[0011] A column 104 is provided on the upper surface of the rear portion (right side in Figs. 1 and 2) of bed 102 so as to be capable of reciprocating 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, and the up-down direction in Fig. 2). A Y-axis slider 106 is provided on the front surface of the column 104 so as to be capable of reciprocating along a Y-axis guide rail (not shown) extending in the up-down direction or the Y-axis direction. A spindle head 108 is attached to the Y-axis slider 106, which supports a spindle 110 so as to be rotatable about a horizontal central axis O. A spindle servo motor (not shown) that rotates and drives the spindle 110 is provided on the spindle head 108.

[0012] A pallet P to which a workpiece mounting fixture M such as a tombstone is attached is removably fixed to the rotating table 114. In this embodiment, the workpiece mounting fixture M has a workpiece mounting surface perpendicular to the Z axis when fixed to the rotating table 114 together with the pallet P, and a workpiece W is attached to this workpiece mounting surface. In this manner, the workpiece W to be machined is mounted so as to face the tool T attached to the tip of the spindle 110. Note that the workpiece W may be fixed directly to the pallet P without using a workpiece mounting fixture M such as a tombstone.

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

[0014] In addition, the machine tool according to this embodiment is equipped with a tool magazine 140 that stores a plurality of tools necessary for machining in the machine tool 100, an automatic tool changer 142 that replaces one of the tools stored in the tool magazine 140 with tool T attached to 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 this embodiment is equipped with a pallet exchange device 130 disposed on the upper surface of the bed 102, in front of the rotary table 114. The pallet exchange device 130 is equipped with a rotating shaft 134 provided rotatably about a vertical rotation axis OV, a rotating arm 132 attached to the upper end of the rotating shaft 134 and extending in the horizontal direction, a rotating door 122 attached to the upper end of the rotating shaft 134 and extending within a vertical plane, a rotating drive device that rotates the rotating shaft 134 about the rotation axis OV, and a rotating arm lifting device that raises and lowers the rotating arm 132.

[0016] In this embodiment, the swivel drive device includes a pallet exchanging servo motor 138 that is rotatable about a swivel axis OV, and a rotary encoder 138a that measures the rotational position (phase) of the pallet exchanging servo motor 138. In addition, 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 parts of the machine tool 100, including the Z-axis slider 112, the rotary table 114, and the spindle 110, the automatic tool changer 142, and the pallet changer 130, are surrounded by a splash guard 120. Also, as shown in Figures 1 and 2, when the rotating door 122 is in a rotation position perpendicular to the Z-axis of the machine tool 100, the space inside the splash guard 120 is divided into a machining chamber 126 in which the Z-axis slider 112, the rotary table 114, the spindle 110, and one end of the rotating arm 132 of the pallet changer 130 (the end indicated by reference number 132b in Figures 1 and 2) of the machine tool 100 are disposed, and a workpiece setup chamber 128 in which the other end of the rotating arm 132 (the end indicated by reference number 132a in Figures 1 and 2) is disposed.

[0018] In order for the operator to access the work setup chamber 128, the splash guard 120 has a work setup chamber opening 120a and a work setup chamber safety door 124 for opening and closing the work setup chamber opening 120a. The work setup chamber safety door 124 is provided with a window for the operator to visually view the inside of the work setup chamber 128. The machine tool 100 is provided with a work setup chamber side operation panel 136 for operating the machine tool 100. The work setup chamber side operation panel 136 is provided with 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 a display device (not shown) for displaying the status of the machine tool 100 and for confirming numerical values ​​input by the operator. The display device can be formed by a touch panel (not shown). Similarly, the machining chamber 126 is equipped with a machining chamber opening 120 b , a machining chamber operator door 125 for opening and closing the machining chamber opening 120 b , and a machining chamber side operation panel 137 for operating the machine tool 100 .

[0019] The control device 150 may be configured by a computer including a CPU (Central Processing Unit), a memory device such as a RAM (Random Access Memory) or a ROM (Read Only Memory), a storage device such as a HDD (Hard Disk Drive) or an SSD (Solid State Drive), an input / output port, a RTC (Real Time Clock), and a bidirectional bus interconnecting these, and associated software. The control device 150 may be configured by software as a 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 a spindle servo motor, an X-axis servo motor, a Y-axis servo motor, a Z-axis servo motor, and a B-axis servo motor.

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

[0021] The operation of this embodiment will now be described. When the machining of the workpiece W is completed, the pallet is replaced. The pallet replacement includes: 1) a first stage in which the pallet P on which the machined workpiece is attached is moved to a pallet replacement position; 2) a second stage in which the swivel arm 132 is raised and the pallet is placed on it; 3) a third stage in which the swivel arm 132 is rotated; and 4) a fourth stage in which the swivel arm 132 is lowered and the pallet is placed on the rotary table 114.

[0022] First, in the first stage, the pallet P on which the machined workpiece W is attached moves in the Z-axis direction toward the pallet exchange device 130 and stops at the pallet exchange standby position. At this time, the first end portion 132b of the rotating arm 132 of the pallet exchange device 130, which extends into the machining chamber 126, enters between the pallet P and the rotary table 114.

[0023] Next, the process moves to the second stage, where the NC device 156 confirms that the rotary table 114 is placed in the pallet exchange standby position, and then outputs a pallet exchange command to the control device 150. Upon receiving the pallet exchange command, the control device 150 outputs a control command to the lifting servo amplifier 158 in accordance with the pallet exchange program stored therein. The lifting servo amplifier 158 outputs a current to the lifting servo motor 144 based on the control command from the control device 150. This rotates the lifting servo motor 144 and the ball screw 146 directly connected to the output shaft of the lifting servo motor 144, and the ball screw nut 148 attached to the lower end of the swivel arm 132 moves upward.

[0024] As a result, 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 of the swing arm 132 extending into the machining chamber 126. After the pallet P is placed on the swing arm, the swing table 114 moves along the Z axis in a direction away from the swing arm 132 to a retracted position where it does not interfere with the swing arm 132, in response to a command from the NC device 156. This completes the second stage of pallet exchange.

[0025] Next, the process moves to the third stage, and the swing servo amplifier 152 outputs a current to the pallet exchanging servo motor 138 based on a control command from the control device 150. This causes the pallet exchanging servo motor 138 to rotate 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 arm 132 finishes swinging, the third stage ends.

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

[0027] During the pallet changing operation, the coolant adhering to the components that rotate together with the rotating arm 132, such as the pallet P, workpiece fixture M, workpiece W, and rotating door 122, is scattered inside the workpiece setup chamber 128 by centrifugal force and adheres to the window of the workpiece setup chamber safety door 124, preventing the operator from observing the inside of the workpiece setup chamber 128. To solve this problem, in this embodiment, the rotation command speed is changed during part of the rotation process of the rotating arm 132 and the rotating door 122, i.e., during a certain section during the third stage of the pallet changing operation.

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

[0029] In FIG. 4, line L1 shows the change in the swing speed during a normal pallet exchange operation in which the swing arm 132 and the swing door 122 are rotated at a swing command speed V1 (hereinafter referred to as a high swing command speed) substantially throughout the entire pallet exchange process. Generally, as described above, it is preferable that the time required for pallet exchange is short, so the high swing command speed V1 is set based on a speed at which the pallet loaded with the workpiece does not fall over due to centrifugal force during rotation, or on the upper limit output of the swing mechanism. Line L2 shows the change in the swing speed during a conventional pallet exchange operation in which the swing arm 132 and the swing door 122 are rotated at a swing command speed V2 (hereinafter referred to as a low swing command speed) lower than V1 in order to prevent or reduce the scattering of coolant. In the conventional technology, the swing speed is reduced from the high swing command speed V1 to the low swing command speed V2 substantially throughout the entire pallet exchange process. This reduces the amount of coolant that is scattered due to centrifugal force during the pallet exchange operation and prevents or reduces the coolant from adhering to the window of the work setup room safety door 124, but it increases the time required for the pallet exchange process from T3 to T5, resulting in a decrease in productivity.

[0030] Line L3 shows the change in the swing speed during the pallet exchange operation according to this embodiment. In this embodiment, after the start of the pallet exchange operation, at time T1, the swing speed is reduced from the high swing command speed V1 to the low swing command speed V2, and at time T2, the swing speed is returned from the low swing command speed V2 to the high swing command speed V1. Of course, if the position of the swing arm at time T2 is close to the swing end position and the return from the low swing command speed V2 to the high swing command speed V1 is not possible in time, the swing speed can be kept at the low swing command speed V2 without returning.

[0031] In this way, in order to reduce the swing speed of the swing arm 132 in a certain section during the pallet changing operation, the timing for reducing the swing speed from the high swing command speed V1 to the low swing command speed V2 and then returning from the low swing command speed V2 to the high swing command speed V1, and the degree to which the swing speed is reduced, or the high swing command speed V1 and the low swing command speed V2, are inputted from the input device 154 to the control device 150. As will be described below, in this embodiment, the input device 154 is formed by a touch panel which is a display device of the work setup room side operation panel 136.

[0032] 5 shows an example of a graphical user interface displayed on a touch panel. A low swing command speed V2, and a speed change start point P1 and a speed change end point P2 for switching the swing speed of the swing arm 132 between the high swing command speed V1 and the low swing command speed V2 are input as parameters for the pallet exchange device 130 to the touch panel serving as the input device 154.

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

[0034] The parameter display area 210 includes an area 212 displaying a phase θ1 of a shift start point P1 at which the swing speed is changed to a low swing command speed V2, an area 214 displaying a phase θ2 of a shift end point P2 at which the swing speed is returned to the high swing command speed V1, and an area 216 displaying the low swing command speed V2. By tapping a point on the trajectory 208 on the graphical user interface screen 200, the phases θ1 and θ2 from the standby position at which the swing door 204 is perpendicular to the Z axis are automatically input, and the operator can 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 swing speed from the high swing command speed V1 to the low swing command speed V2 and for returning from the low swing command speed V2 to the high swing command speed V1 is set in the control device 150 by inputting the speed change start point P1 and the speed change end point P2 via the graphical user interface screen 200. In other words, the graphical user interface screen 200 constitutes a phase setting device that sets the phases of the speed change start point P1 and the speed change end point P2 for switching the swing speed of the swing arm 132 between the high swing command speed V1 and the low swing command speed V2.

[0036] The rotating arm 132 alternates between counterclockwise rotation as shown in Fig. 5 and clockwise rotation in the opposite direction to Fig. 5 every time the pallet is changed. During clockwise rotation, the rotation speed is controlled by replacing P2 with P1 and P1 with P2. Also, the phases θ1 and θ2 do not have to be angles from a standby position perpendicular to the Z axis, but may be angles from the Z axis and the horizontal direction, for example. In short, it is sufficient if the speed change start point P1 and speed change end point P2 can be uniquely determined during pallet change.

[0037] In the embodiment of FIG. 5, the low swing command speed V2 is input as a deceleration rate δ% relative to the high swing command speed V1, rather than directly inputting the reduced swing command speed. The deceleration rate δ% can be input using the keys on the work setup room side operation panel 136, for example, when the operator taps on the area 216, which becomes active. Alternatively, when the operator taps on the area 216, a dialog box (not shown) for inputting the deceleration rate δ% may be displayed in the graphical user interface screen 200. The decelerated low swing command speed V2 may be input directly. Of course, the high swing command speed V1, the low swing command speed V2, and the deceleration rate δ% may be input as G codes, M codes, machine parameters, or NC parameters without using a graphical user interface. Also, the same operation can be performed using the machining room side operation panel 137.

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

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

[0040] According to this embodiment, by reducing the swing speed during a certain section of the pallet changing operation, it is possible to prevent or reduce the adhesion of coolant scattered by centrifugal force during the pallet changing operation to the window of the work setup room safety door 124, without excessively increasing the time required for the pallet changing. According to this embodiment, the time required for the pallet changing process is reduced to T4 from T5 in the conventional technology in which the swing speed is reduced from the high swing command speed V1 to the low swing command speed V2 throughout substantially the entire pallet changing process.

[0041] In the embodiment described above, the work setup room safety door 124 is provided with a window for visually observing the inside of the work setup room 128, but even if a side window (not shown) is provided on the side of the splash guard 120 or an on-board camera (not shown) is provided inside the work setup room 128, it is possible to prevent coolant from splashing onto the side window or the on-board camera.

[0042] At this time, a low swing command speed V3 different from the low swing command speed V2, and an additional speed change start point P3 and speed change end point P4 may be set according to the distance from the side window or the rotating door of the in-flight camera, and the swing speed may be changed in three stages: high swing command speed V1, low swing command speed V2, and low swing command speed V3.In short, the intention of the present invention is to change the speed during pallet exchange at any point in order to prevent coolant from splashing without reducing productivity as much as possible, and therefore the number of changes and the change speed can be freely set.

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

[0044] Although the preferred embodiments of the present invention have been described, the present invention is not limited to the above-described embodiments, and various modifications and improvements are possible, which will be obvious to those skilled in the art. In the example of FIG. 3, the rotary encoder 138a is used to detect the phase or rotation angle of the rotating arm 132, so that the rotating speed is reduced from the high rotating command speed V1 to the low rotating command speed V2 when the speed change start point P1 and the speed change end point P2 are reached, and then returned from the low rotating command speed V2 to the high rotating command speed V1. However, a time counter may be provided to change the rotating speed by measuring the time from the start of the pallet exchange operation.

[0045] In this case, based on the speed change start point P1, speed change end point P2, high swing command speed V1, and low swing 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 pallet exchange until the swing arm 132 reaches the speed change start point P1 and the speed change end point P2, or can measure the time simultaneously with the start of pallet exchange using a time counter and calculate the phase or rotation angle of the swing arm using the control device 150, thereby making it possible to reduce the swing speed from the high swing command speed V1 to the low swing command speed V2 at an appropriate timing, and then return it from the low swing command speed V2 to the high swing command speed V1.

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

[0047] In the modification shown in FIG. 6, the swing drive device includes a hydraulic cylinder 160 instead of the above-mentioned pallet exchange servo motor 138. The hydraulic cylinder 160 swings the swing shaft 134, the swing arm 132, and the swing 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) that engages with the rack gear is coaxially coupled to the swing shaft 134. The swing drive device further includes a hydraulic supply device 170 that supplies hydraulic pressure to the hydraulic cylinder 160, and a time counter 164. If the control device 150 is equipped with an RTC, the time counter 164 may be an RTC.

[0048] 7, a hydraulic supply device 170 shown as an example includes a hydraulic pump 172 that draws hydraulic oil from a hydraulic oil tank 174, pressurizes the hydraulic oil to a predetermined pressure, and supplies the hydraulic oil to the hydraulic cylinder 160. The hydraulic supply device 170 further includes a proportional electromagnetic control valve 176 that is disposed between the hydraulic pump 172 and the hydraulic cylinder 160 and can change the flow rate of hydraulic oil to be output by an electric signal. The proportional electromagnetic control valve 176 can include, for example, a two-position or three-position directional control valve. The hydraulic cylinder 160 extends or retracts according to the position of the directional control 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 in accordance with the pallet exchange program stored therein. The hydraulic pressure supply command is a command signal voltage supplied to a proportional electromagnetic control valve 176. In this embodiment, the hydraulic pressure supply device 170 is equipped with a proportional electromagnetic control valve 176 that can change the flow rate according to the command signal voltage issued from the control device 150, and therefore can change the amount of hydraulic oil supplied per unit time to the hydraulic cylinder 160. When the proportional electromagnetic control valve 176 is closed, the hydraulic oil is collected in a hydraulic oil tank 174 without being supplied to the hydraulic cylinder 160.

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

[0051] In other words, as described above, based on the speed change start point P1, speed change end point P2, high swing command speed V1, and low swing command speed V2 input on the graphical user interface screen 200, the control device 150 can calculate the time from the start of pallet exchange until the phase or rotation angle of the swing arm 132 reaches the speed change start point P1 and the speed change end point P2, or the time counter 164 can measure the time simultaneously with the start of pallet exchange, and the control device 150 can reduce the swing speed from the high swing command speed V1 to the low swing command speed V2 at an appropriate timing for calculating the phase or rotation angle of the swing arm, and then return the swing speed from the low swing command speed V2 to the high swing command speed V1.

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

[0053] In the embodiment described above, the splash guard 120 has a work setup chamber opening 120a through which the operator can access the work setup chamber 128, and a work setup chamber safety door (work setup chamber safety door 124) is provided at the work setup chamber opening 120a so that it can be opened and closed. However, the present invention is not limited to this, and may also be applied to a machine tool used in a so-called automated machining system equipped with a pallet transport line in which the operator does not have access to the work setup chamber.

[0054] Referring to FIG. 8, there is shown another example of a machine tool to which the present invention is applied. 8, machine tool 300 is different from machine tool 100 in that, in principle, an operator does not have access to the setup room. Like machine tool 100, machine tool 300 is equipped with a spindle head 304 that supports a spindle 302 rotatably about a horizontal central axis O, a table 306 that is provided movably in the Z-axis direction, a pallet changer equipped with a rotating arm 308 and a rotating door 310 that are provided rotatably together with a rotating shaft 312 extending vertically, a splash guard 316 that surrounds spindle 302, spindle head 304, table 306, and pallet changers 308, 310, and 312, and a control device 350 that controls machine tool 300.

[0055] In the machine tool 300, the rotating arm 308, the rotating door 310, and the rotating shaft 312 are provided with the rotating drive device (not shown) in the previously described embodiment. Furthermore, like the previously described embodiment, the machine tool 300 is provided with 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 exchange device, i.e., the phase or rotation angle of the rotating arm 308.

[0056] The spindle 302, spindle head 304, table 306, pallet changers 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 previously described embodiment. Although not shown in Fig. 8, the machine tool 300 also includes a tool magazine and a tool changer.

[0057] The machine tool 300 is equipped with a pallet transport device 320. The pallet transport device 320 is equipped with a transport vehicle 322 that is provided so as to be capable of reciprocating along a rail 326 extending in the X-axis direction, and a pallet delivery arm 324 that is mounted on the transport vehicle 322 so as to be capable of advancing and retreating in the Z-axis direction. The pallet delivery arm 324 is capable of accessing the swivel arm 308 of the pallet exchange device in a work setup room 328 through an opening 316a of a splash guard 316. As described above, in this configuration, a plurality of machine tools, not limited to machining centers, pallet stockers for storing machined or unmachined pallets, and work washing devices are arranged along the rail 326, and an automated machining system can be configured in which the transport vehicle 322 transports and delivers pallets between them.

[0058] In this example, the splash guard 316 does not have a work setup room safety door that opens and closes the opening 316a. In this case, in the existing configuration, the coolant splashed from the opening 312a contaminates the floor surface of the pallet transport device 320. If the cut coolant is water-soluble, it will spoil and cause a deterioration of the factory environment such as a foul odor, and if it is water-insoluble, it may cause a fire. In order to manually clean this contamination, it is necessary to stop the transport vehicle 322 for safety, which causes a decrease in productivity. The present invention can be applied to such cases as well, and it is possible to prevent the coolant from splashing out of the splash guard 316 from the opening 316a without excessively increasing the time required for pallet replacement. In this case, the command speed and the speed change point can be set using the machining room side operation panel 318.

[0059] In the above-described embodiment, the machine tools 100, 300 constitute a horizontal machining center, but the present invention is not limited to this and may be a vertical machining center. Furthermore, the present invention is not limited to machine tools and may be applied to, for example, a pallet exchange device of a cleaning device that is installed together with the machine tool 300 in an automated machining system, delivers a pallet carrying a machined workpiece to and from the pallet transport device 320, and automatically cleans the machined workpiece. [Explanation of symbols]

[0060] 100 Machine tools 112 Z-axis slider 114 Rotating Table 120 Splash Guard 120a Work preparation room opening 120b Processing chamber opening 122 Swivel Door 124 Work preparation room safety door 125 Processing room operator door 126 Processing room 128 Work Preparation Room 130 Pallet exchange device 132 Swivel Arm 134 Swivel Axis 136 Work preparation room side operation panel 137 Processing room side operation panel 138 Pallet exchange servo motor 138a rotary encoder 144 Lifting servo motor 150 Control device 152 Swing servo amplifier 154 Input Devices 156 NC device 158 Lift servo amplifier 160 Hydraulic Cylinder 162 Rack and pinion mechanism

Claims

1. In a pallet exchange device for a machine tool that uses a rotating arm to exchange pallets, A rotation drive device capable of switching a rotation command speed to different values ​​while the rotation arm is rotating; a phase setting device that sets a phase for switching the rotation command speed of the rotation arm; a control device that switches a rotation command speed of the rotation drive device in accordance with the phase set by the phase setting device; an input device that inputs a rotation command speed for preventing splashing of coolant due to rotation of the rotation arm to the control device and inputs a phase for switching the rotation command speed to the phase setting device; A pallet exchange device comprising:

2. 2. The pallet exchange device according to claim 1, wherein the phase for switching the rotation command speed includes a speed change start point for switching the rotation speed of the rotation arm from a high rotation command speed to a low rotation command speed, and a speed change end point for switching the rotation speed of the rotation arm from the low rotation command speed to the high rotation command speed.

3. The pallet exchange device of claim 2, wherein the input device is a graphical user interface displayed on a display device, the graphical user interface including a movement trajectory of the swivel arm, and an operator is able to indicate the speed change start point and the speed change end point on the movement trajectory.

4. 2. The pallet exchange device according to claim 1, wherein the turning drive device comprises a servo motor for turning the turning arm about a vertical axis, and a rotary encoder for detecting a rotation angle of the servo motor.

5. 2. The pallet exchange device according to claim 1, wherein the swivel drive device has a servo motor that rotates the swivel arm about a vertical axis, and the phase setting device has a time counter that measures the elapsed time from the start of pallet exchange, and sets the phase for switching the swivel command speed of the swivel arm by the time measured by the time counter.

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