JP2024029974A - Machine tool with gantry loader - Google Patents

Abstract

An object of the present invention is to provide a machine tool with a gantry loader that suppresses the influence of the movement position of a transfer device. [Solution] A bed equipped with a processing section for processing a workpiece, and pillars fixed and erected at both ends of the bed in the left and right width direction, and a support beam with a length exceeding the width dimension of the bed. a gantry loader supported by the pillar and equipped with a transfer device capable of moving a robot hand in a predetermined direction including the left and right width directions along the support beam; and a gantry loader fixed to both ends of the bed in the left and right width direction and extending A machine tool equipped with a gantry loader, comprising: a load adjustment actuator that adjusts the load acting on leveling blocks provided at a plurality of locations to support the bed by the thrust of its tip pressed against the floor surface when activated. [Selection diagram] Figure 1

Description

The present invention relates to a machine tool with a gantry loader, which is integrally assembled with a bed and has a mechanism for suppressing the influence of movement of the loader.

In the lathe described in Patent Document 1 below, the bed of an ultra-precision lathe, which is equipped with a machining section including a spindle device, is attached to the upper surface of a fixed base installed on the floor via a plurality of air springs and hydraulic dampers. It is being Further, a loader support stand equipped with an autoloader is installed straddling the lathe. A hydraulic cylinder provided in such a lathe is configured to push up a piston so that the relative positions of the lathe and the fixed base are fixed. The lathe is designed to absorb external vibrations using air springs and hydraulic dampers to perform cutting operations.

Japanese Patent Application Publication No. 1-58443

By the way, some conventional machine tools such as lathes equipped with an autoloader have a gantry loader integrally constructed by erecting a support on a bed on which the machining parts of each device are mounted. In the gantry loader, the transport device equipped with a robot hand has a wide movement range, so the transport device may overhang outward from the support column. In such a case, the machining section of the machine tool mounted on the bed is affected by the strain that is generated in the bed due to the overhang of the transport device, which may reduce the machining accuracy of the workpiece. On the other hand, overhang is unavoidable because it is necessary to move the transport device outward in order to automatically transport the workpiece to and from a stocker or the like.

SUMMARY OF THE INVENTION In order to solve this problem, it is an object of the present invention to provide a machine tool with a gantry loader that suppresses the influence of the movement position of a transport device.

A machine tool with a gantry loader according to the present invention includes a bed on which a processing section for processing a workpiece is mounted, and pillars fixed and erected at both ends of the bed in the left and right width direction, and the width of the bed exceeds the width dimension of the bed. a gantry loader having a length of a support beam supported by the support column, and a gantry loader equipped with a transfer device capable of moving a robot hand in a predetermined direction including the left and right width directions along the support beam; A load adjustment actuator is fixed to both ends and adjusts the load acting on the leveling blocks provided at a plurality of locations to support the bed by the thrust of the tip pressed against the floor surface by extension operation.

According to the above configuration, the workpiece is processed by the processing section mounted on the bed, and the workpiece is transported by moving the robot hand in the left and right width direction along the support beam using the gantry loader, which is installed on the bed in the processing section. However, at this time, the bed, which was supported by leveling blocks installed at four locations on the front, rear, left, and right, may be deformed due to the load imbalance caused by the movement of the transfer device equipped with a robot hand, so the load The load acting on the leveling block can be adjusted by generating thrust by pressing the tip against the floor by extending the adjustment actuator.

FIG. 1 is a front view simply showing an embodiment of a machine tool with a gantry loader. FIG. 6 is a diagram showing an overhanging state in which the conveyance device has moved beyond the support column to the end side of the support beam. FIG. 3 is an enlarged view of one of the hydraulic cylinders.

An embodiment of a machine tool with a gantry loader according to the present invention will be described below with reference to the drawings. FIG. 1 is a front view simply showing a machine tool with a gantry loader according to this embodiment. This machine tool with a gantry loader (hereinafter simply referred to as a "machine tool") 1 has a bed 3 supported by leveling blocks 4 (4L, 4R) placed at four locations on the front, back, left, and right. It is configured to perform leveling. The machine tool 1 has a spindle device 5 and a turret device 6 mounted on the bed 3, and a gantry loader 7 for transporting a workpiece to be machined.

The main spindle device 5 of the machine tool 1, which is a lathe, is configured such that the center direction of the main spindle is in the width direction of the machine body, which is the longitudinal direction of the bed 3. Therefore, in this embodiment, the body width direction parallel to the main axis is referred to as the Z axis, and the vertical direction orthogonal to the Z axis is referred to as the X axis. The spindle device 5 is rotatably provided with a spindle chuck 11 that grips a workpiece, and rotation is applied to the workpiece gripped by the spindle chuck 11 by driving a spindle motor. In the turret device 6, a plurality of tools are attached to a tool rest 12, and a specific tool can be selected by turning and indexing according to the processing content.

The turret device 6 is provided with a guide rail 13 in the Z-axis direction so that the tool rest 12 can move along the main axis, and it is possible to linearly move the tool that has been rotated and indexed during machining in the Z-axis direction. . That is, the device body 14 is slidably assembled to the guide rail 13, and the device body 14 is moved along the guide rail 13 by a drive mechanism that converts rotation of a Z-axis servo motor into linear motion via a ball screw. Predetermined movement is possible.

Work stockers 70 and 80 are arranged on the left and right outer sides of the machine tool 1, and workpieces are transferred to and from the inside of the machine by a gantry loader 7, which is an automatic workpiece transfer machine. In the case of this embodiment, a plurality of unprocessed workpieces are stored in the workpiece stocker 70 located on the left side of the drawing, and the workpieces processed by the machine tool 1 are collected into the workpiece stocker 80 on the right side of the drawing. The gantry loader 7 has pillars 21 fixed to both ends of the bed 3 in the width direction, and a support beam 23 having a length exceeding the width of the bed 3 is placed at the top in a horizontal state parallel to the Z axis. Fixed. The conveying device 25 assembled so as to be suspended from the support beam 23 is configured to be movable in the Z-axis direction.

In the gantry loader 7, a guide rail parallel to the Z axis is fixed to the support beam 23, and a traveling platform 31 of the transport device 25 is slidably assembled thereto. Further, in addition to the guide rail, a rack parallel to the Z-axis is fixed to the platform beam 23, and a pinion fixed to the rotating shaft of a traveling servo motor provided on the traveling platform 31 meshes with the rack. Therefore, the transport device 25 is moved in the Z-axis direction and positioned in the width direction of the machine body by controlling the rotation of the traveling servo motor. Further, in the transport device 25, a vertical lifting arm 33 is attached to the traveling table 31 so as to be slidable in the X-axis direction.

A rack is fixed to the elevating arm 33 in its longitudinal direction (X-axis direction), and a pinion fixed to a rotating shaft of an elevating servo motor provided on the traveling platform 31 is engaged with the elevating arm 33 . Therefore, the lifting arm 33 is moved in the vertical direction and positioned at a predetermined height by controlling the rotation of the lifting servo motor. A robot hand 35 is attached to the lower end of the lifting arm 33, and the gantry loader 7 positions the robot hand 35 inside or outside the machine by moving the traveling platform 31 and the lifting arm 33. The robot hand 35 includes a pair of chuck mechanisms 51 and 53, each of which can grip and release a workpiece.

Subsequently, in the workpiece machining by the machine tool 1, the workpiece is taken out by the robot hand 35, which is moved to the workpiece stocker 70 by the drive of the gantry loader 7, and the workpiece is carried to the spindle device 5 inside the machine, so that the workpiece is placed in the spindle chuck. 11, the workpiece is transferred to and from 11. In the turret device 6, the tool on the tool rest 12 is rotated and indexed, the device main body 14 is moved along the guide rail 13 by the drive mechanism, and the tool is applied to the rotating workpiece in the spindle device 5 to perform a predetermined job such as outer diameter turning. processing is performed. Then, the processed workpiece is again gripped by the robot hand 35 and transported to the workpiece stocker 80 on the recovery side.

Incidentally, the gantry loader 7 uses a pair of chuck mechanisms 51 and 53 to efficiently transport the workpiece. For example, after a workpiece is taken out from the workpiece stocker 70 by the chuck mechanism 51 and carried into the machine, the empty chuck mechanism 53 receives the processed workpiece gripped by the spindle chuck 11, while the chuck mechanism 51 The gripped workpiece to be processed is transferred to the spindle chuck 11. Thereafter, as described above, the workpiece gripped by the spindle chuck 11 is processed, but in the meantime, the workpiece gripped by the chuck mechanism 53 is transported to the workpiece stocker 80, and the robot hand 35 is also transported to the workpiece stocker 70. It moves again and a new workpiece is taken out by the chuck mechanism 51.

In such work transport, the gantry loader 7 is driven while the machine tool 1 is processing the work, and the transport device 25 is moved to the work stockers 70 and 80. Therefore, the machine tool 1 in which the gantry loader 7 is assembled to the bed 3 is affected by the moving load caused by the transport device 25. This is particularly affected in an overhanging state where the transport device 25 moves toward the end of the support beam 23 beyond one of the two support columns 21 as shown in FIG. 2 . Note that although FIG. 2 shows a case where the transport device 25 moves beyond the support 21 to the work stocker 70 side, the same applies when the conveyance device 25 moves beyond the support 21 to the opposite work stocker 80.

As described above, the transport device 25 is a heavy object that includes the robot hand 35, the lifting arm 33, and the like. Therefore, if it moves beyond the support column 21 to the end side, the support beam 23 becomes cantilevered and a moment is applied, which is applied to the left and right leveling blocks 4 (4L, 4R) that support the bed 3. The load is biased to one side. In other words, the load that the other leveling block 4 receives becomes smaller, and the left and right load balance is lost. Such a change in the load applied to the leveling block 4 causes extremely small deformation in the bed 3, which affects the machining accuracy of the workpiece.

In the machine tool 1, the load is balanced by adjusting the leveling blocks 4 that are supported at four locations, front, rear, left, and right, and the machine tool 1 is installed so that the center of gravity is located approximately in the vicinity of the center of the bed 3. The transport device 25 of the gantry loader 7 is located at the center of the support beam 23 when the load balance is adjusted. Since the bed 3 on which the leveling block 4 has been adjusted is long in the Z-axis direction, the central portion of the bed 3 is bent by its own weight, although it is extremely small. Since such deflection also affects the machine tool 1 which requires high machining accuracy, adjustments are made to the turret device 6 mounted on the bed 3 to achieve tool positioning accuracy. The adjustment is performed on the guide rail 13 arranged in the Z-axis direction, and a precise surface treatment is performed to cancel the deflection of the bed 3.

The position of the tool on the tool rest 12 that moves in the Z-axis direction is adjusted in units of 10 microns. However, as described above, when the conveyance device 25 moves away from the central center of gravity, particularly when it moves beyond the position of the support column 21 to the cantilevered portions 23L and 23R of the support beam 23, the center of gravity changes and the bed 3 This causes extremely small deformation in the area, and the adjusted guide rail 13 is also affected. Therefore, the movement of the tool post 12 that moves along the guide rail 13 is also affected, and the positional accuracy of the cutting edge of the tool is reduced. In other words, machining accuracy will be reduced. Therefore, in this embodiment, a configuration is adopted to suppress the influence on the bed 3 due to the movement of the transport device 25.

In the machine tool 1 of this embodiment, hydraulic cylinders 15 are fixed to both sides of the bed 3 as actuators for adjusting loads. The left and right hydraulic cylinders 15 are provided at substantially the same position as the support column 21, and are fixed at the center position of the leveling block 4L that extends back and forth to the left in the drawing, and at the center position of the leveling block 4R that moves back and forth to the right in the drawing. FIG. 3 is an enlarged view of one of the hydraulic cylinders 15. As shown in FIG. However, in addition to the hydraulic cylinder, a high-thrust electric cylinder or the like may be used as the load adjustment actuator. The hydraulic cylinder 15 is fixed in a contracted state so that a piston rod 55 projects directly below, and a flange 56 that contacts the floor surface is fixed to the tip of the piston rod 55. For example, the stroke of the hydraulic cylinder 15 where the flange 56 contacts the floor surface is set to about 10 mm.

The hydraulic cylinder 15 aims at load adjustment by bearing a part of the load that the leveling blocks 4 (4L, 4R) located on the left and right sides receive. Although the load applied to the left and right leveling blocks 4L and 4R changes as the transport device 25 moves between the left and right columns 21, the influence thereof is considered to be small. On the other hand, when the conveying device 25 moves the cantilevered portions 23L and 23R of the beam 23, a moment M1 acts so that the leveling block 4L or 4R is the fulcrum, and in the case of FIG. The difference in the load received by the leveling block 4L and that of the leveling block 4R becomes large.

As a result, the bed 3 whose load is unbalanced undergoes minute changes due to flexure, which causes changes in the movements of the turret device 6, such as the guide rail 13, which have been precisely adjusted, reducing the accuracy of machining the workpiece. . The hydraulic cylinder 15 suppresses a change in the center of gravity position of the bed 3 that causes such a phenomenon, and applies a moment M2 that cancels the moment M1 generated by the transport device 25. Since the moment M1 of the transport device 25 changes depending on the movement position, it is desirable that the load adjustment actuator adjusts the thrust, and in the case of the hydraulic cylinder 15, the hydraulic pressure applied to the piston is adjusted. However, in this embodiment, since the stop positions of the conveyance device 25 at the cantilever portions 23L and 23R are approximately constant, the hydraulic cylinder 15 generates a thrust force (a moment M2 based on the thrust force) that cancels the moment M1 at that position. The hydraulic pressure is set to

The hydraulic cylinder 15 is a single-acting cylinder configured such that a biasing force of a spring acts in the direction of contraction, and a hydraulic circuit is configured so that the hydraulic oil sent from the hydraulic pump is supplied and discharged by controlling the directional control valve. It is configured. Specifically, the directional control valve is switched by the control device of the machine tool 1, and the hydraulic cylinder 15 in the normal state is released from the hydraulic pressure and is contracted by the biasing force of the spring, so that the flange 56 is separated from the floor surface. There is. During load adjustment where the moment M1 acts due to the movement of the transport device 25, hydraulic pressure is supplied to the hydraulic cylinder 15 and the cylinder 15 is in an extended state.

The directional control valve for extending the hydraulic cylinder 15 is switched at the timing when the conveying device 25 enters the cantilevered portions 23L, 23R. Moreover, the hydraulic cylinder 15 is contracted at the timing when the conveyance device 25 moves from the cantilever portions 23L, 23R to the support portions at both ends between the left and right columns 21. Each timing is determined based on position information calculated based on a detection signal obtained from an encoder of a traveling servo motor that moves the traveling table 31 of the transport device 25 in the Z-axis direction. Alternatively, the determination may be made based on an operation signal transmitted according to the operation program of the gantry loader 7.

Therefore, when the conveyance device 25 moves to the cantilever portions 23L and 23R while the tool is moved to the processing position and the workpiece is processed, the corresponding one of the left and right hydraulic cylinders 15 is extended. The flange 56 is pressed against the floor surface with a predetermined thrust. Therefore, even if the conveying device 25 moves to the cantilevered portion 23L or 23R and a moment M1 is applied with the leveling block 4L or 4R as a fulcrum, the hydraulic cylinder 15 that cancels the moment acts in the opposite direction, M2. act.

Therefore, the situation in which the load applied to the leveling block 4L or 4R, which served as the fulcrum of the moment M1, becomes large and the load balance collapses is improved, and the deformation of the bed 3 is suppressed. By preventing deformation of the bed 3, the positional accuracy of the tool relative to the workpiece can be maintained, and the required machining accuracy for the workpiece can be ensured.

Although one embodiment of the present invention has been described above, the present invention is not limited to this, and various changes can be made without departing from the spirit thereof.
For example, in the embodiment, a lathe is shown as an example of a machine tool, but a machining center, a drilling machine, etc. may also be used.
Furthermore, the gantry loader may also be configured to allow movement in three axes including forward and backward movement.

1... Machine tool with gantry loader 3... Bed 4 (4L, 4R)... Leveling block 5... Spindle device 6... Turret device 7... Gantry loader 11... Spindle chuck 12... Turret 13... Guide rail 15... Hydraulic cylinder 21... Strut 23...Beam 23L, 23R...Cantilever portion 25...Transfer device 31...Traveling platform 33...Elevating arm 35...Robot hand 51, 53...Chuck mechanism 55...Stone rod 56...Flange

Claims (3)

A bed equipped with a processing section that processes the workpiece,
Supports are fixedly erected at both ends of the bed in the left and right width direction, and a support beam having a length exceeding the width dimension of the bed is supported by the support support, including the support beam in the left and right width direction along the support beam. a gantry loader equipped with a transfer device that allows the robot hand to move in a predetermined direction;
A load adjustment device that is fixed to both ends of the bed in the left and right width direction and that adjusts the load that acts on leveling blocks that are provided at multiple locations to support the bed by the thrust of the tip of the bed pressed against the floor surface by extension. an actuator;
A machine tool with a gantry loader. The gantry according to claim 1, wherein the load adjustment actuator generates a thrust force by pressing a tip end against a floor surface when the transport device moves a cantilevered portion protruding from the column of the support beam. Machine tool with loader. 3. The machine tool with a gantry loader according to claim 2, wherein the load adjustment actuator is a hydraulic cylinder whose hydraulic pressure is set according to a stop position of the transfer device at the cantilevered portion.

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