JPH0144468B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a pallet changer for a machine tool, and in particular to a pallet changer for placing a workpiece between the pallet magazine located at the front of the machine tool and the machine tool. A pallet changer of a machine tool that performs pallet exchange by twisting the orientation of the workpiece mounting surface of the pallet between the horizontal exchange position on the magazine and the horizontal attachment position in the pallet attachment part of the machine tool. Regarding ya.

[Conventional technology]

As a pallet changer that automatically exchanges a pallet on a pallet table with a workpiece mounted thereon and a pallet on a work table of a machine tool with a machined workpiece mounted thereon, it is possible to change the pallet from the horizontal pallet stand to the horizontal pallet table. A number of systems have already been proposed in which automatic exchange of pallets is carried out by transferring the pallets to and from a work table while maintaining their horizontal orientation.

JP-A No. 56-9153 discloses an example of such a conventional pallet changer that rotates a pinion using the rotational movement of a machine table of a machine tool, and moves a carriage rack that is constantly engaged with the pinion in the X direction. The carriage of the pallet changer is moved in the X direction by movement, and the pallet is transferred from the carriage of the pallet changer by the movement of the column in the Z direction, which is equipped with a special tool for changing pallets on the spindle of the machine tool. , discloses a configuration for export. In addition, Utility Model Application No. 57-157441 has a structure in which a pallet placed on a cart, which is arranged in an oval shape on the side of the machine table and guided by a rail, is carried into and out of the machine table using a hydraulic cylinder. Disclosed.

Furthermore, the present applicant and the same applicant's JP-A-60-
No. 167420 discloses a pallet changer that simultaneously grips a pallet on a pallet table and a pallet on a work table with two pairs of gripping arms, and can automatically exchange the pallets with each other by rotating 180 degrees.

The above is a conventional technique for automatically exchanging pallets in a horizontal plane, but it is similar to the technique for automatically exchanging pallets between a work table with a vertical mounting surface of a machine tool and a horizontal pallet stand. For example, Japanese Patent Application Laid-Open No. 59-107839 is an example of this technique.
This discloses a technology for a handling robot that mutually exchanges workpieces between the vertical workpiece mounting surface of the chuck of a lathe and a workpiece magazine adjacent to the lathe where the workpieces are placed horizontally. Two hands are provided at the tip of the robot arm, one of which grips a new workpiece and waits at a standby position. When a workpiece exchange command is issued, the robot arm first swings toward the chuck side.
Grip the processed workpiece attached to the chuck with the other empty hand. Then, the entire robot arm moves to the right to remove the machined work from the chuck, and then only the hand rotates 180 degrees to direct the new work toward the chuck. The entire robot arm moves to the left and attaches a new workpiece to the chuck. Next, the robot arm swings upward to a vertical position, and then swings 90 degrees toward the workpiece table. Next, the robot arm descends and places the work into the work magazine. Then, the robot arm rises, the work magazine indexes the next work, the robot arm descends, grips the next work, swings 90 degrees to the standby position, and indexes the next work in an upward vertical position. Wait until a replacement order is issued.
This handling robot has two actuators for performing the above-mentioned movements: two for type 2 singing, one for rotating the hand part 180 degrees, one for left and right movement, and one for raising and lowering. 5
pcs are required.

[Problem that the invention seeks to solve]

When exchanging a pallet placed horizontally on a pallet magazine and a pallet placed horizontally vertically on a machine tool, the aforementioned lathe work handling robot can be applied.
Requires a large number of actuators. This poses a problem in that not only the structure becomes complicated, but also the drive control device becomes large-scale and the control method becomes complicated.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a compact and inexpensive pallet with a small number of actuators that can exchange two pallets that are twisted by 90 degrees with each other by a translational movement and a single rotational movement. The purpose is to provide the following information.

[Means for solving problems]

In view of the above-mentioned object of the invention, the present invention provides a pallet changer that automatically exchanges pallets while rotating them between a machine tool and a pallet magazine disposed in front of the machine tool. a changer saddle that is movable reciprocally along a fixed path provided between the changer saddle and the magazine; and a changer saddle that is provided to be pivotable about a horizontal axis provided on the changer saddle to a pallet exchange position of the pallet magazine. A swing arm that swings over a predetermined angle between the machine tool and the pallet mounting portion, and a housing that is connected to the tip of the swing arm with a pin, and has gripping axes swinging 90 degrees to each other on both sides of the housing. a gripping device equipped with a pair of pallet grippers, the swinging arm being a driving node, the changer saddle being a fixed node, and the housing of the gripping device being a horizontally movable node, which is parallel to the swinging arm and having both ends connected to the changer saddle; and a parallel link mechanism that uses a rod pin-coupled to the housing of the gripping device as a driven link to move the pallet gripped by the gripping device in a horizontal state between the pallet magazine and the machine tool side; a rotation mechanism for rotating the pair of pallet grippers around a first axis in a horizontal direction connecting the centers of the pair of pallet grippers; and a rotation mechanism for rotating the pair of pallet grippers around a second axis perpendicular to the first axis. A rotating mechanism for rotating the pallet grippers, and a pallet gripper turning device for rotating the pair of pallet grippers by 180 degrees by the rotating mechanism and 90 degrees by the rotating mechanism at the same time, To provide a pallet changer for a machine tool configured so that a pallet horizontally placed at a pallet exchange position and a pallet horizontally mounted on a pallet mounting part of the machine tool can be mutually rotated and replaced.

[Effect]

According to the above means according to the present invention, a pair of pallet grippers can simultaneously turn 180 degrees and rotate 90 degrees around two orthogonal axes, so that two pallets that are twisted 90 degrees relative to each other can be translated. It can be replaced with one turning operation. Hereinafter, the present invention will be explained in more detail based on embodiments shown in the accompanying drawings.

〔Example〕

FIG. 1 is a schematic front view showing a pallet changer according to the present invention together with a pallet magazine and a machine tool, FIG. 2 is a plan view of FIG. 1, and FIG.
An enlarged sectional view of the gripping device along the arrow line in the figure,
4 is a sectional view taken along the arrow line - in FIG. 3, and FIG. 5 is an explanatory diagram of the operation of the pallet changer according to the present invention.

First, referring to Figure 1, pallet magazine 1
A pallet changer 40 according to the present invention is disposed on a changer base 18 installed between the pallet changer 0 and the machine tool 20. Said pallet magazine 1
A workpiece is placed on the pallet table 12 of 0.
Pallet A with item a attached is placed so that the pallet surface is horizontal. The machine tool 20 also includes a column section 24 having a spindle head 28 and a bed section 22 on which a work table 26 is mounted.A rotary table 30 is attached to the work table 26. A pallet B carrying a processed workpiece B is attached to the pallet mounting portion 29 so that the pallet surface is perpendicular to the side surface (a plane parallel to the plane of the paper in FIG. 1).

A pallet changer 40 that automatically exchanges the pallet B on which the work b is also loaded and the pallet A on which the work a is loaded is provided with a gripping device comprising a housing 44 and a pallet gripping arm 41. At both ends of the pallet gripping arm 41 of the gripping device, there are a pallet gripper (hereinafter referred to as gripper) 42A for gripping pallet A and a gripper 42B for gripping pallet B, each with their gripping axes aligned.
They are arranged horizontally and vertically with a 90 degree twist. Note that a turning device for turning both grippers 42A and 42B will be described later. The pallet gripping arm 41 is supported by the housing 44 via the turning device. On the other hand, two guideways 46 are disposed on the changeer base 18 in a direction connecting the pallet stand 12 for pallet exchange of the pallet magazine 10 and the pallet mounting section of the machine tool 20. The guideway 46
A chain seat saddle 48 is mounted which is slidable along. At the top of the saddle 48 is a horizontal shaft 50.
A housing shaft 51 is provided horizontally to the horizontal shaft 50 and the housing 44.
A swing arm 52 is attached between the two shafts 50 and 51 so as to be pivotable, and the upper part of the saddle 48 is a fixed joint, and the fixed joint, the swing arm 52, and the A rod 54 for forming a parallel link mechanism in combination with the housing 44 is disposed parallel to the swing arm 52 and is connected to the upper part of the saddle 48 and the housing 44 with a pin.

An arm 58 is provided on the segment gear 56 which is rotatable around the horizontal axis 50 and is arranged to mesh with the gear 49 fixed to the swing arm 52, and a pin 63 is attached to the tip of the arm 58. A connecting member 59 is attached via. Further, a hydraulic reciprocating actuator (second cylinder) 60 is fixed to the saddle 48, and the reciprocating movement of the actuator 60 is transmitted to the connecting member 59 via a pin 65 at the tip of the piston. As a result of this reciprocating motion, the arm 58 is given a rocking motion, and the segment gear 56 can be rotated forward and backward (rotated) around a pin (another horizontal axis) 62 fixed to the saddle 48. This rotation of the segment gear 56 is transmitted to the gear 49, causing the swing arm 52 to swing. At this time,
Since the swing arm 52 forms a parallel link mechanism together with the rod 54 and the housing 44 as described above, the pallet gripping arm 4 is supported by the housing 44 via a fixed shaft 78 (FIG. 3), which will be described later.
1 swings and moves while maintaining a horizontal state. Note that the stroke of the reciprocating actuator 60 is determined by an appropriate stopper (not shown), and in this embodiment, the horizontal height of the pallet gripping arm 41 is at a position P1 after swinging, which is the same as the pallet mounting position of the machine tool 20. The stroke is set so that the oscillating movement can be made up to .

The pallet gripping arm 41 that has oscillatedly moved to the same height position P1 in this way is moved to the position P2 where the gripper 42B grips the pallet B of the machine tool 20.
need to be moved to. Therefore, the saddle 48 is moved along the guideway 46 by a saddle reciprocating actuator (first cylinder) 64 fixedly supported on the cylinder support 19 of the base 18.
Move in a straight line along. In this case as well, the stroke of the actuator 64 is set by a suitable stopper.

The second diagram shows a plan view of the pallet changer 40, pallet magazine 10, and machine tool 20 according to the present invention as outlined above.
It is a diagram. A plurality of pallets carrying workpieces are mounted on the pallet magazine, and in this figure, a desired pallet is transported to a pallet exchange position P0 by a command control unit (not shown), and a desired pallet A is transferred by a gripper 42A. The figure shows a state in which it is being held. The completion of gripping the pallet A by the gripper 42A is detected by a dog and a limit switch (not shown). Further, the work table 26 of the machine tool 20 is horizontally movable in the axial direction (X direction) of the pallet mounting section 29.

Next, FIG. 3 shows the gripping device in a sectional view taken along the arrow line - in FIG. First, the turning mechanism of the turning device will be explained.
Rack 70 is in the vertical direction (perpendicular to the paper in Figure 3)
, the pinion 72 meshing with the rack 70 rotates, and the T-shaped cylinder 76 that is integrally fixed to the pinion 72 via a key 74 rotates.
rotates. The T-shaped cylinder 76 and the pinion 72 are fixed horizontally (parallel to the plane of the paper in FIG. 3) to the housing 44 by a plurality of screws 77.
It pivots around a horizontal fixed shaft 78 extending in the direction through a pusher 80 and through another pusher 82 between it and the housing 44 .

Next, the rotation mechanism of the rotation device will be explained. The T-shaped cylindrical body 76 supports the gripper shaft 84 so as to be rotatable around its axis (first axis), and the axis is coincident with the axis of the horizontal fixed shaft 78 (second axis). is perpendicular to and at the same height. Moreover, the gripper 42A and the gripper 42B are fixed to both ends of the gripper shaft 84 so that their gripping axes are twisted 90 degrees with respect to each other. Furthermore, the horizontal fixed shaft 7
A large sun gear 86 and a planetary gear 88, which are made of bevel gears, are fixed to the tip of the T-shaped cylinder 76 of No. 8 and the outer periphery of the gripper shaft 84 at appropriate axial positions so as to mesh with each other. , the gripper shaft 84 has a bush 90 between it and the T-shaped cylinder 76.
The gripper shaft 84 is rotatable around the axis of the gripper shaft 84 via the gripper shaft 84 . Further, the sun gear 86 does not rotate because it is fixed to the horizontal fixed shaft 78. Note that the number of teeth of the sun gear 86 and the planetary gear 88
The number of teeth is set at a ratio of 1:2.

By reciprocating the rack 70 in a manner to be described later, the pallet gripping arm 41 is pivoted around the horizontal fixed shaft 78 via the pinion 72 and the T-shaped cylinder 76. In this case, the planet gear 88 rotates around the axis of the gripper shaft 84 while revolving around the sun gear 86 fixed to the horizontal fixed shaft 78, but as described above, the number of teeth of the sun gear 86 and the planet gear Since the ratio of 88 teeth is 1:2, the ratio of the angle of revolution to the angle of rotation is 2:1. For example, when the pallet gripping arm 41 rotates (revolutions) 180 degrees around the axis of the horizontal fixed shaft 78, the pallet gripping arm 41 rotates (rotates) 90 degrees around the axis of the gripper shaft 84.

In this embodiment, since the fixed shaft 78 is provided in the horizontal direction as the second axis, the pallet gripping arm 41
is 180 in the vertical plane around its horizontal fixed axis 78.
It turned once. Here, the gripper shaft 8 which is the first axis
4 remains in a horizontal state, a fixed shaft serving as a second axis is vertically provided, and a sun gear 86 is attached to the vertical fixed shaft so as to mesh with a planetary gear 88. Of course, the pinion 72, T-shaped cylinder 76, etc. are also provided around this vertically fixed shaft, and the rack 70 is also provided so as to reciprocate in the horizontal direction. Then, the pallet gripping arm 41 rotates 180 degrees in the horizontal plane around the fixed vertical axis. In this case as well, both grippers 42A and 42B can perform a 90 degree twisting rotation at the same time as the 180 degree rotation. Therefore, as long as the second axis is perpendicular to the horizontally provided first axis, the same action and effect will be achieved whether the second axis is horizontal or vertical.

Figure 4 shows Rack 7 according to the arrow line in Figure 3.
FIG. Pistons 94a and 94b are inserted into the cylinder 96, and a rack 70 guided by a guide 92 is disposed between the pistons 94a and 94b. Said piston 94a is pushed up by pressure oil supplied from the lower pressure oil supply port 98a under suitable control means, thereby pushing up the rack 70. At this time, the pinion 72 engaged with the rack 70 is driven to rotate. Further, the piston 94b is pushed down by the pressure oil supplied from the upper pressure oil supply port 98b under the appropriate control means, and the rack 70 is pushed down.
As a result, the pinion 72 is rotated in a direction opposite to the aforementioned rotational direction. This causes the pallet gripping arms 41 to pivot in opposite directions. The length of the cylinder 96 is set so that the stroke of each piston 94a or 94b corresponds to the rotation of the pallet gripping arm 41 by 180 degrees.

When manufacturing a cylinder with such a long stroke, it is generally ground from both ends to form a single cylinder bore. In this case, due to problems with machining accuracy, the entire cylinder bore cannot be centered on one axis, and a slight misalignment inevitably occurs. When a long rack that also serves as a piston is inserted into such a cylinder bore, the piston (rack) becomes distorted as it reciprocates, and the piston (rack) is used in a state in which it does not slide smoothly. This causes wear between the piston and cylinder, and eventually a phenomenon called "galling" occurs in which the piston becomes clogged with wear particles and stops moving. In this embodiment, in order to solve this problem, two short pistons are provided, a rack slightly smaller than the cylinder bore is disposed between them, and the rack is guided by the dovetail 93 of the guide 92. When the rack moves upward, it is actuated by the lower piston, and when it moves downward, it is actuated by the upper piston. In other words, each of the two pistons has 1
Since it reciprocates only within the cylinder bore formed by the shaft center, there is no chance of prying, and eventually "galling"
can be prevented.

The operation of the pallet changer according to the present invention having the above structure will be explained with reference to FIG. 5 as well as FIGS. 1 to 4. FIG. 5a shows a state in which the pallet changer 40 has been moved by the saddle reciprocating actuator 64 from its retracted position to the position where it grips pallet A of the pallet magazine 10. In this state, the horizontal gripper 42A grips the pallet A, and when the dog and the limit switch detect the completion of gripping, the reciprocating actuator 60 operates, and the pallet gripping arm 4
1 moves in translation while maintaining a horizontal state, and stops at a position P1 where the horizontal height of the pallet gripping arm 41 is at the same height as the pallet device position of the machine tool 20 by means of a suitable stopper. b illustrates this state.

Next, the saddle reciprocating actuator 64 is actuated to horizontally move the saddle 48, and the vertical gripper 42B reaches a position P2 where it grips the pallet B vertically attached to the machine tool 20. When the pallet B is gripped by the gripper 42B, the work table 26 moves back relative to the bed 22 in the "X" direction shown in FIG. 2 (toward the back side of the paper in FIG. 1). In this way, the pallet B is removed from the machine tool while being gripped by the grippers 42B. c indicates this state.

Next, the rack 70 is moved from top to bottom by hydraulic pressure, and this movement causes the pallet gripping arm 4 to move.
1 is rotated 180 degrees counterclockwise around the horizontal fixed shaft 78, and both grippers 42A and 42B are rotated (rotated) 90 degrees around the axis of the gripper shaft 84 via the gripper shaft 84. In this way, pallets A and B are exchanged with each other, and this state is shown at d. Further, from this state, the work table 26 moves forward (from the back side to the front side of the paper in FIG. 1), and a new pallet A is loaded. d also shows this state.

After installing a new pallet A on the rotary table 30 of the machine tool, the pallet changer 40 is returned to the pallet magazine 10 side by the saddle reciprocating actuator 64 while holding the pallet B. This state is shown in e.

Next, the reciprocating actuator 60 places the pallet B on the pallet stand 12 of the pallet magazine 10 while keeping the pallet gripping arm 41 in a horizontal state. f indicates this state.

Finally, the pallet changer 40 is moved to its retracted position using the reciprocating actuator 64, the rack 70 is moved from bottom to bottom, the pallet gripping arm 41 is rotated 180 degrees clockwise, and the gripper 42A picks up the pallet. The gripper 42B faces the magazine 10 side and the gripper 42B faces the machine tool 20 side, respectively, in preparation for the next pallet exchange. This state is g
Shown below.

〔Effect of the invention〕

As is clear from the above description, it is possible to simultaneously generate a 180 degree rotation of the pallet gripping arm and a 90 degree twisting rotation of the two grippers by one actuation of one linear actuator. Two linear actuators are provided for transporting pallets between the pallet magazine and the machine tool. Furthermore, the loading and unloading of pallets on the rotary table on the machine tool utilizes the X-direction feeding function originally possessed by the machine tool. Therefore, the pallet changer of the present invention is capable of mutually exchanging a pallet placed vertically on a pallet magazine and a pallet placed horizontally vertically on a rotary table of a machine tool using only three actuators. can. In other words, the structure is compact, the control method is simple, and an inexpensive pallet changer can be provided.

In addition, a rack sandwiched between two pistons that move linearly within the cylinder is used as a linear actuator that rotates the pallet gripping arm 180 degrees and twists the two grippers 90 degrees. There is no galling of the piston due to misalignment errors between the top and bottom of the cylinder during long strokes, which inevitably occurs, and smooth and reliable rotation of the pallet gripping arm can be achieved.

[Brief explanation of drawings]

FIG. 1 is a schematic front view showing a pallet changer according to the present invention together with a pallet magazine and a machine tool, FIG. 2 is a plan view of FIG. 1, and FIG.
An enlarged sectional view of the gripping device along the arrow line in the figure,
FIG. 4 is a sectional view taken along the arrow line - in FIG. 3, and FIG. 5 is an explanatory diagram of the operation of the pallet changer according to the present invention. 10... Pallet magazine, 12... Pallet stand, 18... Changer base, 19... Cylinder support stand, 20... Machine tool, 22... Bed section, 24... Column section, 26... Work table , 28... spindle head, 29... pallet mounting part,
30... rotary table, 40... pallet changer, 41... pallet gripping arm, 42
A, 42B...Pallet gripper, 44...Housing, 46...Guideway, 48...Change saddle, 49...Gear, 50...Horizontal shaft, 5
2... Swinging arm, 54... Rod, 56... Segment gear, 58... Arm, 59... Connecting member, 60... Reciprocating actuator, 62... Pin (other horizontal axis), 64... Reciprocating actuator for saddle, 70...Rack, 72...Pinion, 76...T-shaped cylinder, 78...Horizontal fixed shaft,
84...grip shaft, 86...sun gear, 88...
...Planetary gear, 92...Guide, 94a, 94b...
...Piston, 96...Cylinder, 98a, 98b
...Pressure oil supply port.

Claims (1)

[Scope of Claims] 1. In a pallet changer that automatically exchanges pallets while rotating them between a machine tool and a pallet magazine disposed in front of the machine tool, a changer saddle that is movable back and forth along a fixed path; and a changer saddle that is pivotable about a horizontal axis provided on the changer saddle to change the pallet exchange position of the pallet magazine and the pallet of the machine tool. A swinging arm swings over a predetermined angle between the swinging arm and the mounting part, and a pair of pallet grippers having gripping axes twisted 90 degrees to each other on both sides of a housing pin-connected to the tip of the swinging arm. a gripping device comprising a gripping device, the swinging arm being a driving node, the chainer saddle being a fixed node, and the housing of the gripping device being a horizontally movable node; a parallel link mechanism that uses a rod pin-coupled to the housing as a driven link to move the pallet gripped by the gripping device in a horizontal state between the pallet magazine and the machine tool side; A rotation mechanism that rotates the pair of pallet grippers around a first axis in a horizontal direction that connects the centers of the pair of pallet grippers, and a turning mechanism that rotates the pair of pallet grippers around a second axis that is orthogonal to the first axis. The pallet gripper rotates the pallet grippers horizontally at the pallet exchange position of the pallet magazine. A pallet changer for a machine tool configured to mutually rotate and exchange a mounted pallet and a pallet mounted laterally on a pallet mounting portion of the machine tool. 2. The changer saddle is installed between the machine tool and the pallet changer, is provided on the changer base, and is reciprocated by a first cylinder along a guideway that forms the constant path. A pallet changer for a machine tool according to claim 1. 3. The swing arm is meshed with a gear that rotates in forward and reverse directions around another horizontal axis parallel to the horizontal axis axis in accordance with the operation of a second cylinder provided in the changer saddle. Claim 1 or 2, which is operated by a swinging mechanism configured by providing a gear at the rear end of the swinging arm concentrically with the horizontal axis axis. The pallet changer for the machine tool described in section. 4. The pallet gripper turning device includes a cylindrical body in which the turning mechanism of the turning device can turn around the second axis concentrically with the second axis, and a rack and pinion mechanism that drives the cylindrical body to turn. The rotation mechanism of the rotation device is rotatably supported by the cylinder, the rotation shaft having the first axis as the axis and having the pair of pallet grippers fixed to both ends thereof; a non-rotating sun gear consisting of a bevel gear fixed concentrically to the second axis with respect to the housing forming the horizontally moving node; and a bevel gear meshing with the sun gear and concentrically fixed to the rotating shaft. A pallet chip for a machine tool according to any one of claims 1 to 3, comprising a planetary gear, wherein the ratio of the number of teeth between the sun gear and the planetary gear is 1:2. Engineer. 5. The rack and pinion mechanism includes two pistons that reciprocate within a cylinder provided in the housing of the gripping device using fluid pressure, a rack that is sandwiched between the two pistons from both sides and reciprocates, and the rack. A rack guide is provided in the cylinder and guides the rack so as to maintain uniform meshing with the pinion over the entire stroke. A pallet changer for a machine tool according to claim 4.