JPH08141867A - Pallet changing device for machine tool - Google Patents

Abstract

PURPOSE: To provide the pallet changing device for machine tool, which can secure the arrangement space under a change arm and in which the weight of a frame can be reduced and the structure thereof can be simplified. CONSTITUTION: This pallet changing device 50 for machine tool, which is provided with an elevation driving mechanism 13 for driving elevation of a change arm 9 and a turning driving mechanism 10 for driving rotation of the change arm 9, turns pallets W1, W2 for transference between a working table and a waiting station. The elevation driving mechanism 13 is arranged under the change arm 9, and a frame 25 is stretched over the change arm 9, and the turning driving mechanism 10 is arranged in the frame 25, and an arm shaft 7, which is vertically extended over the change arm 9, is connected to a turning shaft 30, which is vertically extended under the turning driving mechanism 10, freely to be moved in the axial direction and freely to transmit the rotating force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pallet exchanging device for a machine tool in which a pallet on which a work (workpiece) is placed is automatically exchanged between a machining table and a standby station by an exchanging arm.

[0002]

2. Description of the Related Art For example, a machine tool such as a machining center may be equipped with a pallet exchanging device for automatically exchanging a machined work and a machined work in order to improve productivity. As a pallet exchanging device of this type, for example, Japanese Patent Publication No. 2-20374 discloses an elevating and lowering drive mechanism for supporting a pivot shaft of a pallet exchanging arm by a base and raising and lowering the pivot shaft on the base, and a pivot drive. There has been proposed a device provided with a swiveling drive mechanism. The pallet exchanging device of this prior art has a structure in which a mechanism for raising and lowering and revolving the revolving shaft is disposed on the base below the exchanging arm.
There is a problem that the arrangement space of these mechanisms becomes large, the accessibility of the operator is deteriorated, and work is hindered, and the arrangement space of other devices becomes narrow.

On the other hand, Japanese Utility Model Publication No. 6-27309 discloses that
A frame having a frame structure composed of columns and beam members is installed above the bed of the machine tool, and the arm shaft of the exchange arm is extended vertically upward, and the extension is supported by the frame so that it can be raised and lowered and rotated. There has been proposed a structure in which an elevating drive mechanism for elevating and lowering the arm shaft and a swivel drive mechanism for swivel driving are provided on this mount. According to this, since each drive mechanism is arranged on the pedestal above the pallet, accessibility of the operator is improved and work is not hindered, and other devices are accommodated below the exchange arm. Space can be secured.

[0004]

However, in the case of the structure in which both the raising and lowering drive mechanism and the turning drive mechanism of the above-mentioned prior art are arranged on the gantry, all the weights of the pallet, the exchange arm, the work, etc. act on this gantry. Therefore, there is a problem that the pedestal must be a large-scale frame structure having extremely high rigidity capable of supporting these heavy objects. Further, it is necessary to arrange hydraulic pipes and the like for driving the lifting drive mechanism on the pedestal located above, which causes a problem that the structure becomes complicated accordingly.

The present invention has been made in view of the above-mentioned conventional circumstances, and a machine tool which does not require so much rigidity of the gantry and can be simplified in structure while ensuring a space for disposing below the replacement arm. It is intended to provide a pallet changing device.

[0006]

In order to achieve the above-mentioned object, the present inventor has a difference in the role sharing between the lifting drive mechanism and the turning drive mechanism, that is, although the lifting drive mechanism is extremely heavy, We paid attention to the fact that the space required for the swivel drive mechanism is small, whereas the space required for the swivel drive mechanism is large, depending on the structure. Further, by disposing the elevating drive mechanism below the replacement arm, it is possible to significantly reduce the weight burden on the gantry, and to minimize the reduction of the installation space below the replacement arm. On the other hand, the present invention has been completed in view of the fact that by disposing the turning drive mechanism on the gantry, the arrangement space below the replacement arm can be reduced without increasing the weight burden of the gantry.

In view of this, the present invention comprises a replacement arm which is arranged to be movable up and down and rotatable, a lifting drive mechanism which drives the replacement arm up and down, and a swing drive mechanism which swings the replacement arm. In a pallet exchanging device for a machine tool that swivels between a machining table and a standby station, the elevating drive mechanism is arranged below the exchanging arm, and a mount is installed above the exchanging arm. The swing drive mechanism is provided, and an arm shaft extending vertically above the exchange arm is connected to a swing shaft extending vertically below the swing drive mechanism so as to be movable in the axial direction and capable of transmitting a rotational force. I am trying.

[0008]

According to the pallet exchanging device of the present invention, since the lifting drive mechanism is provided below the exchanging arm and the swing drive mechanism is provided on the gantry, the weights of the exchanging arm, pallet, work, etc. are all below the exchanging arm. The pedestal is supported on the base side, and the pedestal only needs to support the weight of the turning drive mechanism among the member weights. As a result, the pedestal can be made less rigid as compared with the case where both conventional drive mechanisms are mounted on the pedestal, and the weight of the gantry can be reduced and the cost can be reduced accordingly. Further, since it is not necessary to route the hydraulic pipes constituting the lifting drive mechanism on the pedestal, the structure can be simplified also from this point.

Further, since the turning drive mechanism is provided on the mount,
Compared to a system in which both drive mechanisms are provided below the replacement arm, the space below the replacement arm is wider, so that the operator's accessibility is improved and work is not hindered, and the storage space for other devices etc. Can be secured.

By the way, it is possible to dispose only the turning drive mechanism below the exchange arm and mount only the elevating drive mechanism on the gantry. In such a case, however, both drive mechanisms are used as described above. Due to the large difference in the weight sharing ratio of the above, the weight acting on the gantry is not so small as compared with the case where the both mechanisms are mounted on the gantry.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 6 are views for explaining a pallet changing device for a machine tool according to an embodiment of the present invention, FIG. 1 is a schematic configuration diagram of the pallet changing device of the present embodiment, and FIG. 2 is a device of the present embodiment. FIG. 3 is a sectional front view showing the lifting drive mechanism of FIG. 3, FIG. 3 is a sectional side view showing the swivel drive mechanism of the apparatus of this embodiment, FIG. 4 is a sectional view taken along the line IV-IV of FIG. 3, and FIG. FIG. 6 and FIG. 6 are schematic configuration diagrams of a machine tool in which the device of this embodiment is adopted.

In the figure, reference numeral 1 is a machine tool provided with the pallet changing device of this embodiment, which is mainly composed of a column 3 arranged at a right end portion of a bed 2 shown in the drawing so as to be movable in a direction perpendicular to the plane of the drawing. A tool mounted on the spindle 4 includes a spindle 4 movably mounted on the column 3 in the vertical direction, and a processing table 5 disposed on the upper surface of the bed 2 movably in the lateral direction in the drawing. The work W1 placed on the processing table 5 is processed by 4a.

At the left end of the machine tool 1 in the figure, a pallet changing device 50, which characterizes this embodiment, is provided. The pallet exchanging device 50 is for automatically exchanging the pallets 11, 11 between the waiting station 45 and the processing table 5 moved to the left end in the figure on the bed 2, and is configured to be rotatable and movable up and down. Replacement arm 9
And a lifting drive mechanism 13 for driving the replacement arm 9 up and down.
And a swivel drive mechanism 10 for swiveling the exchange arm 9.
And a pedestal 25 that supports the turning drive mechanism 10.

The exchange arm 9 extends vertically upward, and an arm support flange 8 is integrally formed at the lower end of an arm shaft 7 having a hollow tip, and a pair of arm bodies 9a and 9b are formed on the arm support flange 8. It has a structure in which it is bolted and fixed. The arm bodies 9a and 9b are substantially U-shaped in a plan view and extend in the horizontal direction so as to form a right angle with the arm shaft 7.

The lifting drive mechanism 13 has a cylindrical cylinder body 14a in a support hole 6a formed in a base 6 fixed on the bed 2, and a guide shaft located at the axis of the cylinder body 14a. Cylinder 14 composed of 14b is inserted and fixed, piston 15 is slidably inserted into cylinder 14, and piston flange 16 is bolted and fixed to the upper end edge of piston 15. The piston flange 16 is located in a recess 8a recessed in the lower surface of the arm support flange 8, and between the outer peripheral surface of the piston flange 16 and the inner peripheral surface of the recess 8a of the arm support flange 8. A cross roller bearing 17 is provided in the above. In this way, the arm shaft 7 is rotatably supported by the piston 15 of the lifting drive mechanism 13 such that the arm shaft 7 cannot move axially relatively.

The bottom surface of the piston 15 and the cylinder shaft 14
The outer peripheral surface of b and the inner peripheral surface of the cylinder body 14a form an ascending hydraulic chamber 20, and the outer peripheral surface of the piston 15 and the inner peripheral surface of the cylinder body 14a form a descending hydraulic chamber 21. Further, a hydraulic passage 22a communicating with the hydraulic chamber 20 for raising is formed in the bottom wall portion of the cylinder shaft 14b.
Hydraulic passages 22b and 22c communicating with the descending hydraulic chamber 21 are formed from the bottom wall portion 4b to the cylinder body 14a, and hydraulic pumps are connected to the hydraulic passages 22a to 22c via hydraulic pipes (not shown). Has been done. By supplying hydraulic oil to the hydraulic chamber 20 for raising, the piston 15 raises the exchange arm 9, and by supplying hydraulic oil to the hydraulic chamber 21 for lowering, the piston 15 lowers the exchange arm 9.

The pedestal 25 has a structure in which columns 26, 26 are erected on the left and right sides of the bed 2, and a beam member 25a is erected between the upper ends of the columns 26, 26. The support plate 28 is fixed.

The swing drive mechanism 10 is disposed on the support plate 28, and has a gear box 27 fixed on the support plate 28, a gear box 27 rotatable therein, and the arm shaft. 7, a swivel shaft 30 arranged coaxially, a roller cam 42 rotatably provided in the gear box 27 and orthogonal to the swivel shaft 30, and rotating the swivel shaft 30. A motor 35, which is fixed to the outer surface of the gear box 27 and rotates and drives the roller cam 42, is provided.

The swivel shaft 30 extends downward through the bottom wall 27a of the gear box 27, and the lower end 30a of the swivel shaft 30 is axially slidably inserted into the arm shaft 7. . The swivel shaft 30 is rotatably supported by a bearing 31 mounted on the bottom wall 27a and a bearing 33 mounted on the ceiling wall 27b.

Two keys 34 extending in the axial direction are connected to the lower end portion 30a of the swivel shaft 30.
Is slidably fitted in a key groove 7a formed on the inner peripheral surface of the arm shaft 7. As a result, the arm shaft 7 is slidable in the axial direction with respect to the turning shaft 30 and is rotationally driven by the turning shaft 30.

A spline or a coupling may be used for the connecting structure of the arm shaft 7 and the turning shaft 30.
Further, the connecting position of the arm shaft 7 and the turning shaft 30 is determined by the beam member
It is not limited to the vicinity of a, but for example, the arm shaft 7 is shortened, the turning shaft 30 is extended downward, and the arm support flange 8 is provided.
You may combine in the vicinity of. Further, in the case of the key groove connection or the spline connection, a through hole is provided from the shortened upper end of the arm shaft 7 to the bottom surface of the arm support flange 8 and the swivel shaft 30 is provided.
May be inserted into the arm support flange 8. On the contrary, in the vicinity of the beam member 25a, the distal end portion of the swivel shaft 30 may be hollow and the arm shaft 7 may be fitted therein, or the swivel shaft 30 may be provided with a through hole so that the swivel shaft is provided in the gear box 27. The arm shaft 7 may be fitted and inserted in 30.

The roller cam 42 and the turning shaft 30 are well-known low gear cams. A guide groove 42a is formed on the outer peripheral surface of the roller cam 42, and the guide groove 42a is rotatably mounted on the turning shaft 30. The roller 43 is rotatably fitted, and when the roller cam 42 is rotated, the swivel shaft 30 is rotated. A drive shaft 37 is inserted into the shaft center of the roller cam 42 and is key-connected, and the drive shaft 37 is rotatably supported by both side walls 27c and 27d of the gear box 27 via bearings 38 and 39. . A driven gear 41 is fixed to the drive shaft 37, and a driven gear 40 fixed to the output shaft 35a of the drive motor 35 is meshed with the driven gear 41.

Next, the operation of the pallet changing device 50 of this embodiment will be described. In the machine tool 1 of this embodiment, the workpiece W1 on the machining table 5 is machined according to a machining program previously input to the controller. During this processing, the operator sets the work W2 on the pallet 11 on the waiting station 45. When the machining of the work W1 is completed, the machining table 5 enters the substantially U-shape of the arm body 9a or 9b without interference and moves to the exchange position A (see the chain double-dashed line in FIG. 6). In this case, the exchanging arm 9 of the pallet exchanging device 50 is located at the lower end, and the arm bodies 9a and 9b are located slightly below the pallets 11 and 11.

A hydraulic chamber 20 for raising by driving a hydraulic pump
When the hydraulic oil is supplied to the exchange arm 9, as shown on the left side of FIG. 2, the exchange arm 9 rises together with the piston 15, and the arm bodies 9a and 9b push up the pallets 11 and 11 at the same time.
As a result, the pallets 11 and 11 are lifted from the processing table 5 and the standby station 45.

In this state, when the drive motor 35 is activated and the roller cam 42 is rotationally driven, the cam groove 42a of the roller cam 42 guides the roller 43, whereby the rotary shaft 3 is rotated.
0 rotates the arm shaft 7, and along with this, the arm body 9
a and 9b turn 180 degrees. As a result, the processed work W1 is reversed and transferred to the waiting station 45 side and the work W2 is reversed to the processing table 5 side.

Next, when the hydraulic oil is supplied to the descending hydraulic chamber 21 by switching the hydraulic passages and the hydraulic oil in the ascending hydraulic chamber 21 is discharged, as shown in the right side of FIG. At the same time, the exchange arm 9 descends, the pallets 11 and 11 are placed on the processing table 5 and the standby station 45, respectively. Further, when the exchange arm 9 descends, the arm bodies 9a and 9b separate below the pallets 11 and 11. . Then, the processing table 5 moves to the spindle 4 side, and the processing of the work W2 is started. On the standby station 45 side, the processed work W1 is removed and the next work is set.

As described above, according to this embodiment, the lift drive mechanism 13 for moving the exchange arm 9 up and down is disposed on the bed 2, and only the turning drive mechanism 10 is mounted on the mount 25 installed above the arm shaft 7. Since the weights of the exchange arm 9, the pallets 11 and 11, the works W1 and W2, etc. are all supported by the bed 2, the pedestal 25 has only the weight of the turning drive mechanism 10 among the member weights. Will work. As a result, it is not necessary to increase the rigidity of the gantry 25 so much, the frame structure can be lightened and simplified, and the cost can be reduced.

Further, in this embodiment, since the structure in which the roller cam 42 is rotated by the drive motor 35 is adopted as the turning drive mechanism 10, it is sufficient to wire only the motor power supply cord to the mount 25, and the hydraulic cylinder is adopted. The structure can be simplified as compared with the hydraulic piping in this case, and the cost can be reduced from this point as well.

Furthermore, in this embodiment, since only the elevating and lowering drive mechanism 13 is arranged below the exchanging arm 9, the elevating and lowering drive mechanism and the swinging drive mechanism are arranged below the exchanging arm 9 as compared with the case where both are arranged. The space can be reduced, the accessibility of the operator is improved and work is hardly hindered, and a storage space for other devices such as a cutting oil tank can be secured below the replacement arm 9.

[0030]

As described above, according to the pallet exchanging device for a machine tool according to the present invention, the elevating drive mechanism is provided below the exchanging arm, and only the turning drive mechanism is provided on the mount installed above the exchanging arm. Since it is provided, exchange arm, pallet,
It is possible to avoid that the weight of the work or the like acts on the gantry, reduce the rigidity required for the gantry, reduce the weight and simplify the gantry, and reduce the cost. The structure can be simplified also because it is not necessary to route the constituent hydraulic pipes to the frame.

Further, since the turning drive mechanism is provided on the gantry, the space below the exchange arm is wider and the operator's accessibility is improved as compared with the case where both drive mechanisms are provided below the exchange arm. This has the effect of avoiding obstacles to work and ensuring a storage space for other devices and the like.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram for explaining a pallet changing device for a machine tool according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an up-and-down drive mechanism of the apparatus of the above embodiment.

FIG. 3 is a sectional side view showing a turning drive mechanism of the apparatus of the embodiment.

FIG. 4 is a cross-sectional view (cross-sectional view taken along the line IV-IV in FIG. 3) showing a connecting portion between the arm shaft and the swivel shaft of the above embodiment.

FIG. 5 is a cross-sectional plan view showing a turning drive mechanism of the apparatus of the embodiment.

FIG. 6 is a schematic configuration diagram showing the apparatus of the above embodiment and a machine tool employing the apparatus.

[Explanation of Codes] 1 Machine tool 5 Machining table 9 Exchange arm 10 Swiveling drive mechanism 11 Pallet 13 Elevating drive mechanism 25 Stand 45 Standby station 50 Pallet changer W1, W2 Work

Claims (1)

[Claims] 1. A pallet processing table, comprising: an exchange arm arranged to be movable up and down and rotatably, an elevation drive mechanism for raising and lowering the exchange arm, and a swing drive mechanism for swinging the exchange arm. In a pallet changer for machine tools that swivels between a machine and a standby station,
The elevating drive mechanism is disposed below the exchange arm, a gantry is installed above the exchange arm, the slewing drive mechanism is disposed on the gantry, and the slewing shaft extends vertically below the slewing drive mechanism. A pallet exchanging device for a machine tool, wherein an arm shaft extending vertically above the exchanging arm is connected so as to be movable in the axial direction and capable of transmitting a rotational force.