JPH0443729B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to mounting a workpiece on a pallet, and placing the pallet at a fixed retracted position with a table of a machine tool such as a machining center, such as a pallet on which a replacement pallet is placed. The present invention relates to an improvement in a pallet changer for a machine tool that automatically supplies workpieces to the machine tool and takes out processed workpieces by automatically exchanging the pallet changer with a table or the like.

Conventional technology The basic operation of this type of pallet changer is to load the workpiece to be machined onto a pallet, transport the workpiece to the machine tool table via this pallet, retreat while the workpiece is being machined, and place the workpiece on the pallet. After that, the processed work is carried out via a pallet, and the next work is carried in.

Two pairs of exchange arms that can open and close, which hold the pallet from both sides, are used to carry out the above operation.
It is arranged symmetrically so that it can rotate 180 degrees with the center of rotation between the table top of the machine tool and the top of the pallet table remote from the machine tool, and the opening/closing mechanism, vertical movement mechanism, and rotation movement of the exchange arm are located at the center of rotation. A device equipped with a mechanism is disclosed in Japanese Patent Application Laid-Open No. 62-28149.

Problems to be Solved by the Invention The above-mentioned conventional apparatus has a structure in which the exchanging arm opens and closes on both sides, so it has low rigidity, is not suitable for large pallets, and is difficult to increase speed.

In addition, in the conventional device, the opening/closing mechanism and the vertical movement mechanism of the exchange arm are provided at the center of rotation via two types of cam mechanisms in the first cylinder, and the two pairs of exchange arms are operated symmetrically at the same time. In order to do this, a link mechanism is provided, and a pivoting mechanism consisting of a second cylinder and a rack and pinion is provided at the pivot center position, making the structure extremely complicated.

In addition, in conventional equipment, the exchange arm is retracted to a position open on both sides during processing of the workpiece, and the opening/closing mechanism and the vertical movement mechanism of the exchange arm are shared by one cylinder. It is becoming difficult to use it as an exchange method.

The present invention was proposed in view of the above-mentioned problems of conventional devices, and its purpose is to provide a pallet exchange function with high speed and excellent stability for large and rectangular pallets in a small amount of space. The objective is to provide a pallet changer for machine tools that has the following features.

Means for Solving the Problems In order to achieve the above object, the present invention includes a main body frame, a rotating lifting shaft supported upright on the main body frame so as to be rotatable and movable up and down, and an arm fixed to the upper end of the rotating lifting shaft. The base is mounted on the arm base so that it can move straight in the horizontal direction between the table of the machine tool and the position evacuated from the table, and pallets are removably placed on both ends of the machine tool in the straight direction. It is equipped with an exchange arm, a linear movement mechanism for the exchange arm installed on the main body frame, an elevating mechanism for the swivel elevating shaft installed on the main body frame, and a turning mechanism for the swivel elevating axis installed on the main body frame.

Furthermore, the present invention provides a machine tool table and a corresponding pallet stand having a turret structure capable of arranging a plurality of pallets, and an elevating mechanism for a rotating lift shaft that is connected to the machine tool table and a pallet stand having a turret structure. It can be raised and lowered in two stages.

Function: The exchange arm moves up and down and rotates integrally with the arm base, with pallets placed on both ends, and moves straight ahead independently.

The exchange arm has a rotating structure that allows it to rotate 180 degrees between the machine tool table and the pallet stand.

At the end of the turning operation, the elevating mechanism lowers the pallet and transfers the pallet on the exchange arm onto the table and pallet stand of the machine tool. After the transfer, the exchange arm is retracted from the table of the machine tool by the linear movement mechanism, and the work on the pallet transferred to the table is processed by the machine tool.
During this time, the pallet loaded with the next workpiece is placed on one end of the exchange arm. After machining the workpiece, the exchange arm moves straight and enters the position corresponding to the pallet on the table of the machine tool. and,
It moves upward and receives the pallet on the machine tool table. Then it turns 180 degrees and descends. As a result, the pallet loaded with the next workpiece is transferred onto the table of the machine tool, and the pallet loaded with the processed workpiece is transferred onto the pallet stand. After the transfer, the exchange arm is retracted from the table of the machine tool by the straight mechanism and the above operation is repeated.

When using a pallet stand with a turret structure, the elevating mechanism is raised and lowered in two stages, and by lowering the first stage, the pallet on the exchange arm is transferred to the table of the machine tool and the pallet stand, and then the pallet is moved to the second stage. By lowering the exchange arm, a pallet stand having a pallet structure passes over the exchange arm, and a pallet on which the next work is mounted is prepared while the work is being processed.

Embodiment In FIG. 1, A generally indicates a pallet changer of the present invention, which automatically exchanges a pallet E between a table C of a machine tool B and a pallet stand D.

The above pallet changer A has main body frame 1.
, a rotating lift shaft 2 , an arm base 3 , an exchange arm 4 , a straight moving mechanism 5 , a lifting mechanism 6 , and a turning mechanism 7 .

The turning and lifting shaft 2 is supported by the main body frame 1 in an upright state so that it can rotate and move up and down, and has an arm base 3 fixed to its upper end.

The exchange arm 4 is located on the arm base 3, on the table C of the machine tool B, and in a position retracted from this table C toward the pallet table D (position shown by the chain line in Fig. 1).
The pallet E is installed so that it can be moved straight in the horizontal direction, and pallets E are removably positioned and placed at both ends in the above-mentioned straight direction.

The exchange arm 4 has the shape of two parallel forks with a substantially vertically elongated hexagonal cross section and a chevron shape at the top and bottom, and has a locking protrusion 4a at both ends, and a recess ( (not shown) are formed on the pallet E, and the pallet E is positioned on the exchange arm 4 by their engagement.

The straight moving mechanism 5 consists of a fluid pressure cylinder 5a fixedly installed on the main body frame 1 and its piston rod 5b. The exchange arm 4 is configured to engage in position and move the exchange arm 4 in a straight line. Note that the linear mechanism 5 may have a motor and feed screw structure instead of the fluid pressure cylinder 5a. In addition, although the locking protrusion 4a was also used,
May be done separately.

As shown in FIG. 4, the elevating mechanism 6 includes two sets of two-stage operating cylinders 6a interposed between the main body frame 1 and an elevating plate 8 connected to the lower end of the rotating elevating shaft 2 via a thrust bearing. , 6b, and pistons 6d and 6e are fixed to both ends of a piston rod 6c, and these pistons 6d and 6e are connected to the cylinder 6, respectively.
The upper cylinder 6a is fixed to the main body frame 1, the lower cylinder 6b is fixed to the elevating plate 8, and both raising and lowering are operated in two stages. In addition, the lifting mechanism 6
It is also possible to configure it with a one-stage cylinder, and it is also possible to use a motor and a feed screw structure instead of the cylinder.

The turning mechanism 7, as shown in FIGS. 5 and 6,
A motor 7a fixed to the main body frame 1, a camshaft 7c rotating from the motor 7a via a transmission gear device 7b, and a camshaft 7c fixed on the camshaft 7c,
A roller gear cam 7d having a spiral groove (not shown) on its outer circumferential surface, a turret 7f having rollers 7e fitted in the spiral grooves of the roller gear cam 7d radially at equidistant positions on the outer circumferential surface, and a spline shaft 7g to which the turret 7f is fixed. It consists of a spline gear 7h fixed to the spline shaft 7g, and a drive gear 7i meshed with the spline gear 7h and fixed to the swing lift shaft 2.

The spline shaft 7g is rotatably supported on the main body frame 1 in parallel with the turning and lifting shaft 2, and the cam shaft 7c is rotatably supported on the main body frame 1 orthogonal to the spline shaft 7g. The roller gear cam 7d and the turret 7f are
Since the roller 7e is fitted into the spiral groove, they mesh in a relationship similar to that between a worm gear and a worm wheel, thereby transmitting the rotation of the roller gear cam 7d to the turret 7f. In this case, the roller gear cam 7d cannot be rotated from the turret 7f side, has a locking function similar to a worm lock, and can smoothly transmit rotational force without backlash. Incidentally, the turning mechanism 7 may be of a rack and pinion type.

The pallet stand D may be a single one, but
As shown by the chain lines in Fig. 1, pallet stands D are arranged at equidistant positions around the circumference of the turret F, so that not only the same work but also different types of work can be prepared to accommodate high-mix, low-volume production. It can be a multi-palette method.

As shown in FIG. 4, the exchange arm 4 is clamped to the arm base 3 by a clamper 10 operated by a clamp cylinder 9 provided on the arm base 3. position) and the retracted position are determined by fitting the positioning pin 11a of the positioning cylinder 11 provided on the arm base 3 into the positioning hole 4b of the exchange arm 4, and these mechanisms are symmetrical in Fig. 4. However, in FIG. 4, only one of each is shown.

The operation of the embodiment according to the present invention will be described below.
The exchange arm 4 is in the forward position by the linear movement mechanism 5, and is raised one step from the lowermost position by the lifting mechanism 6, and is moved from the pallet stand D on the turret F.
Receive the first pallet E. Then, it rises one more step, and in this state, the turning mechanism 7 turns it 180 degrees. Subsequently, the first pallet E is transferred onto the table C of the machine tool B by descending one step. Then, after descending one more step, the straight moving mechanism 5 moves backward and waits, and the workpiece on the table C is processed by the machine tool B. During machining, the pallet E on which the next workpiece is mounted is indexed by the turret F to an exchange position and stands by.
After machining, the exchange arm 4 moves forward by the linear mechanism 5, ascends one step, receives the pallet E located at the exchange position on the turret F side at one end, and then ascends another step to transfer it to the machine tool B. pallet E on table C is received at the other end. and,
Turn 180 degrees (either in the same direction or in the opposite direction) to move the next pallet E onto the table C of the machine tool B, and move the processed pallet E onto the replacement position of the turret F. Next, the exchange arm 4
The lifting mechanism 6 lowers the pallet one step and transfers the next pallet E onto the table C of the machine tool B. It then descends one more step and transfers the processed pallet E to the pallet stand D at the replacement position of the turret F. After that, the straight moving mechanism 5 moves backward and waits. During this time, processing is performed on the table C, and the processed pallet E is carried out from the turret F side, and the next pallet E is indexed and carried in. Thereafter, the above-described operations are repeated.

Although we have described the case in which the exchange arm 4 is raised and lowered in two steps, this is a one-step raise and lower operation, and the parts E on the pallet table D can be replaced manually or by a loading/unloading means such as a robot. You can let it.

Effects of the Invention According to the present invention, the structure is simple, and the pallet exchange arm is a single piece with a vertically elongated hexagonal cross section, thereby improving stability and rigidity during pallet loading. In addition, since the pallet exchange arm moves in a straight line, in the case of rectangular pallets, the arm moves in a skewering manner, making it possible to make the arm base small and strong, thereby reducing space. Furthermore, since the elevating mechanism is independent of the turning mechanism and the straight moving mechanism, there are advantages such as easy multi-pallet exchange system.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view of a pallet changer showing an embodiment of the present invention, FIG. 2 is a schematic side view thereof,
FIG. 3 is a schematic front view, FIG. 4 is a longitudinal sectional front view showing an example of the lifting mechanism, FIG. 5 is a longitudinal sectional side view showing an example of the turning mechanism, and FIG. 6 is a cross-sectional plan view of the roller gear cam section in FIG. 5. It is. A...Pallet changer, B...Machine tool,
C...Table, D...Pallet stand, E...Pallet, F...Turret, 1...Main frame, 2
...Swivel lifting axis, 3... Arm base, 4... Exchange arm, 5... Straight movement mechanism, 6... Lifting mechanism, 7...
...Swivel mechanism.

Claims (1)

[Scope of Claims] 1. A main body frame, a swivel lift shaft that is supported upright on the main body frame so as to be rotatable and movable up and down, an arm base fixed to the upper end of the swivel lift shaft, and a workpiece on the arm base. A replacement arm is installed so that it can move straight horizontally between the table of the machine and a position evacuated from the table, and removably places pallets on both ends of the machine, and a replacement arm that is installed on the main body frame. A pallet changer for a machine tool, characterized in that it is equipped with a linear movement mechanism for an arm, a lifting mechanism for a rotating lifting shaft installed on a main body frame, and a turning mechanism for a turning lifting axis installed in the main body frame. 2. The table of the machine tool and the corresponding pallet stand have a turret structure that allows for arranging multiple pallets, and the elevating mechanism of the rotating lifting axis is installed on the table of the machine tool and the pallet stand of the turret structure.
2. The pallet changer for a machine tool according to claim 1, wherein the pallet changer is capable of being raised and lowered in stages. 3. A pallet changer for a machine tool, wherein the structure of the arm base, exchange arm, and pallet mounting portion according to claim 1 is comprised of a chevron shape and a V-groove that fits the chevron shape.