JP3073648B2 - Pallet positioning mechanism for machining eccentric parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pallet positioning mechanism for carrying a pallet on which a workpiece is mounted to a machine tool, rotating the workpiece together with the pallet, and performing a turning operation even at an eccentric position of the workpiece.

[0002]

2. Description of the Related Art For example, in order to mount a work 32 having an eccentric portion shown in FIG. 4 on a pallet and perform turning at an eccentric position, the pallet on which the work (material) is mounted is loaded on a rotary table. The center line 34 of the workpiece (material) is made to coincide with the center line of rotation of the rotary table. In this state, the rotary table is rotated to turn a predetermined portion 33 of the workpiece.

[0003] Next, the operator removes the workpiece from the pallet, repositions the center 37 of the portion to be subjected to eccentric machining to the rotation center of the rotary table, and reattaches the workpiece to the pallet. Thereafter, turning processing is performed on the desired eccentric cylindrical portion 36. When re-attaching the workpiece, another pallet prepared for setup using a loader or the like may be used.

[0004]

When a workpiece is fixed on a pallet and carried into a machine tool, the shape of the workpiece is special and complicated, and it is often difficult to grip the workpiece with a general chuck. In many cases, automation is not possible if only the workpiece is handled. Such a work requires a lot of time and setup to be mounted on the pallet, which not only increases the ratio of the time required for mounting to the pallet to the total work time, but also causes the eccentric part as described in the prior art. There is a problem in that re-attaching the workpiece to turn the workpiece has an adverse effect on time and cost.

According to the present invention, when turning an eccentric portion of a workpiece mounted on a pallet, the pallet is automatically moved, so that the time required for changing the processing position is reduced, and the position change is performed. The purpose is to reduce the cost of the product by eliminating the need for special setup.

[0006]

In order to achieve the above object, a pallet positioning mechanism for machining an eccentric part according to the present invention is detachably mounted on a pallet on which a workpiece is placed by a clamp member capable of tightening and loosening. A rotary table rotatable around a vertical rotation axis and a column having a vertically movable spindle head are provided so as to be movable relative to each other in a direction perpendicular to the rotation axis. In a machine tool for turning a workpiece on a pallet with an attached tool, a connecting means is provided for connecting the pallet to the column so that the pallet can be put on and off, and prevents movement of the connecting means in a direction perpendicular to the rotation axis. A braking member which can be freely applied and detached is provided, and the pallet is connected to the column by the connecting means, and the rotary table is rotated by the relative movement between the rotary table and the column. It is intended to position the pallet in the desired position in the direction perpendicular to the line.

The connecting means is a pallet holding device, which has a hook-like portion at the tip of the piston rod to be inserted into a concave portion of the pallet and projects from a cylinder in parallel with the piston rod.
A lock for holding the pallet in cooperation with the hook
A first piston cylinder member which is movable in horizontal direction toward a de, the interposed first piston cylinder member
Pressure to urge piston rod forward and said rod backward
Inserting the compression spring and the hook into the recess of the pallet
Therefore, the first piston cylinder member is moved up and down.
A second piston cylinder member that, said first piston cylinder unit after rise of the oil feeding oil pressure to the second piston cylinder member
And a hydraulic sequence circuit for feeding oil to the material and clamping the pallet .

[0008] An air circuit is used instead of the hydraulic circuit.

[0009]

The pallet on which the workpiece is mounted is carried on the rotary table, and after the clamp, the rotary table is rotated to perform turning. Thereafter, the clamp is released, the pallet is held by the holding device, and the holding state is maintained by the braking member. In this state, the column is moved to move the pallet to a predetermined position on the table, and clamping is performed again. Thereafter, the rotary table is rotated again to perform turning at the eccentric position.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall view of a vertical machining center, which is an example of a machine tool to which the present invention is applied, and a saddle 2 is movably mounted on an upper front side of a T-shaped base 1 horizontally in the X-axis direction. The turntable 3 is mounted on the saddle 2. Further, a column 4 is erected in the back of the T-shaped base 1 so as to be movable horizontally in the Y-axis direction, and a spindle head 5 is movably mounted on the front surface of the column 4 vertically in the Z-axis direction. A spindle 6 for mounting a tool is provided below the spindle head 5.
Is provided.

FIG. 2 shows a device for fixing the pallet 7 to the rotary table 3, and a hollow rotary shaft 8 is vertically supported on the saddle 2. The rotary shaft 8 and the rotary table 3 are fitted via a key. Then, the rotating shaft 8 is appropriately rotated by transmitting a rotating force to the gear 9 by a driving source (not shown). The pallet 7 is provided with a vertically movable clamp shaft 10 at the center of a rotating shaft 8 having a hollow cross section opened downward, and is inserted into a groove of the pallet 7 at the upper end of the clamp shaft 10. Is fixed to the rotary table 3.

A pallet 7 is provided on the upper surface of the clamp plate 11.
A roller 12 is attached for contacting the groove bottom surface and smoothly moving the pallet 7. Clamp shaft 10
A piston cylinder member 13 for pallet clamping is attached to the lower end of the pallet, and raises the clamp shaft 10 and the clamp plate 11. Further, between the hollow rotary shaft 8 and the clamp shaft 10, a disc spring 14 for pressing the clamp shaft 10 and the clamp plate 11 downward is interposed.

FIG. 3 shows a pallet holding device for repositioning the pallet 7 carried on the rotary table 3, and a window 1 is provided at a position facing the pallet 7 on the front surface of the column 4.
5 is provided. A vertical guide 4 a is provided inside the column 4, and a holding device main body 16 is provided on the guide 4 a so as to be vertically movable, and a lower end of the main body 16 is provided with a vertically upward 2 piston cylinder member 17
Connected to a piston rod. A small first piston cylinder member 18 for a pallet holding rod is attached to the main body 16 so as to be movable in the Y-axis direction with respect to the main body 16.

The front piston rod 19 of the first piston cylinder member 18 protrudes outward from the window 15 toward the pallet, and its tip 20 is bent upward like a hook. The rear piston rod 21 of the first piston cylinder member 18 is releasably braked by a braking device 22 for stopping the movement of the piston. Cylinder 2 of first piston cylinder member 18
From 3, a rod 24 projects outward from the window 15 in parallel with the piston rod 19. A compression spring 25 is mounted in the rear chamber of the cylinder 23, and constantly urges the piston rod 19 to move forward and the rod 24 to move backward.

Pressure oil from a pump 27 is sent to a lower chamber 26a of a cylinder 26 of the second piston cylinder member 17 via a three-position switching electromagnetic valve 28. Further, pressure oil is sent from the pump 27 to the front chamber 23 a of the cylinder 23 through the branch flow path via the check valve 30 and the two-position switching electromagnetic valve 31.

Next, the operation of the embodiment will be described for the case of processing the workpiece 32 shown in FIG. First, the pallet 7 to which the material of the workpiece 32 is attached is carried into the rotary table 3 of the vertical machining center and is placed on the rollers 12 of the clamp plate 11. At this time, the center line 34 of the first cylindrical portion 33 of the workpiece
And the rotation center line of the turntable 3 are aligned.

Next, when the pressure oil in the lower chamber of the piston cylinder member 13 is switched to the discharge side, the clamp shaft 10 and the clamp plate 11 are lowered by the disc spring 14, and the pallet 7 is pressed against the rotary table 3 and clamped. Thereafter, when the rotating shaft 8 is rotated by a driving source (not shown), the rotary table 3 is rotated.
At the same time, the pallet 7 rotates, and the turning is performed by the tool attached to the main shaft 6, whereby the turning of the cylindrical portion 33 about the center line 34 is performed.

After the turning of the cylindrical portion 33 is completed, the rotary table 3 is rotated by a drive source (not shown) so that the groove direction of the pallet 7 coincides with the Y-axis direction. In this state, set column 4 to Y
The shaft is advanced to make the tip hook 20 of the piston rod 19 coincide with the concave portion 35 formed in the ceiling of the pallet 7 in the Z-axis direction. Then, the three-position switching electromagnetic valve 28 is switched to the a position and the two-position switching electromagnetic valve 31 is simultaneously switched to the d position, and the lower chamber 26a of the cylinder 26 of the second piston cylinder member 17 is passed through the three-position switching electromagnetic valve 28 by the pump 27. Send pressure oil.

At this time, the pressure oil to the branch passage is supplied to the check valve 3
Oil supply is stopped by a spring force of zero. When the holding device main body 16 connected to the piston rises and the upper end of the hook 20 is inserted into the concave portion 35 of the pallet 7 and the tip abuts on the ceiling of the concave portion, the main body 16 is prevented from rising and the cylinder lower chamber 26 is closed. pressure of the oil is increased, the pressure oil from the branch passage against the spring force of the check valve 30 is fed into the front chamber 23a of the cylinder 23 via the 2 position changeover valve 31.

When pressure oil is sent to the front chamber 23a of the cylinder 23, the piston rod 19 and the tip hook 20
The tip hooks abut against the rear wall in the recess 35 of the pallet 7. At the same time the cylinder 23, the rod 24 abuts against the outer wall of the rod 24 tip pallet 7 moves forward against the body 16. That is, the pallet 7 is held between the hook 20 and the rod 24. In this state, the rear piston rod 21 is immovably gripped by the braking device 22 and the sandwiching state of the pallet 7 is maintained.

The pressure oil is sent to the lower chamber of the piston cylinder member 13 to raise the piston, the rotating shaft 8 and the clamp plate 11 to release the clamping of the pallet 7. The Ann click <br/> to follow the pallet 7 rise during lamp increases with body 16, three-position changeover valve by the signal of the pallet clamp release 28 is the lower chamber of the switched cylinder 26 in position C 26
a is closed to prevent the body 16 from descending.

After that, the column 4 is moved in the Y-axis direction,
The pallet 7 is moved on the rollers 12 of the clamp plate 11 so that the center line 37 of the second cylindrical portion 36 coincides with the center line of the rotary table 3 for positioning. And 3 position switching solenoid valve 2
After switching the position 8 to the position b to allow the holding device main body 16 to descend, the pallet 7 is clamped to the rotary table 3.

Next, when the braking of the rear piston rod 21 is released by the action of the braking device 22 and the two-position switching solenoid valve 31 is switched to the position e, the piston advances by the action of the compression spring 25 and at the same time the cylinder 23 retreats. The holding of the pallet 7 is released, whereby the cylinder lower chamber 26 is released.
The oil inside is discharged into the tank 38 and the holding device main body 16 descends by its own weight. Then, the turning of the eccentric cylindrical portion 36 is performed.

By setting the groove width of the T-shaped groove provided on the pallet 7 to be larger than the clamp plate 11 so that the saddle 2 can be held in a state where the pallet is clamped after the clamp is released. By moving the shaft, the eccentric turning can be performed on a center line other than the plane including the two center lines 34 and 37.

In this embodiment, a machine tool in which the column 4 moves in the Y-axis has been described. However, a machine tool in which the column 4 is fixed and the rotary table 3 can move in the Y-axis can be used. Of course.

[0026]

According to the first aspect of the present invention, it is possible to easily and automatically position a work for turning in an eccentric portion of the work in a short time.

The effect of claim 2 is that, since the pallet holding portion is constituted by the piston cylinder itself, no additional operating member for holding is required, the structure is simple and the cost is low.
Also, the hydraulic circuit sends hydraulic pressure to the second piston cylinder member.
Oil rises to the first piston cylinder member after
Since a hydraulic sequence circuit is used to hold the unit, no means for checking each operation is required, and the structure is simple and the cost is low.

The effect of claim 3 is that the air circuit is used instead of the hydraulic circuit, so that there is no fear of oil leakage and the cost is reduced.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of a vertical machining center according to the present embodiment.

FIG. 2 is an explanatory diagram of a pallet clamp structure.

FIG. 3 is an explanatory view of a pallet holding device.

FIG. 4 is an external view of a workpiece having an eccentric portion for explaining the operation of the present embodiment and the operation of a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 T-type base 2 Saddle 3 Rotary table 4 Column 7 Pallet 11 Clamp plate 16 Nipping device main body 17 Second
Piston cylinder member 18 First piston cylinder member 22 Braking device 28 3-position switching solenoid valve 30 Check valve 31 2-position switching solenoid valve

Claims (3)

(57) [Claims] 1. A rotary table rotatable around a vertical rotation axis, which is detachably mounted by a clamp member capable of tightening and loosening a pallet on which a workpiece is placed, and a spindle head movable vertically. A column having a pallet that is rotatable relative to the axis of rotation in a direction perpendicular to the axis of rotation, and the workpiece mounted on the pallet is turned by a tool attached to the spindle head. A connecting means for removably connecting the connecting means to prevent movement in a direction perpendicular to the rotation axis of the connecting means; and a releasable braking member for connecting the pallet to the column by the connecting means and the rotating table. A pallet for machining an eccentric part, wherein the pallet is positioned at an arbitrary position in a direction perpendicular to the rotation axis on a rotary table by relative movement between columns. Positioning mechanism. 2. The pallet clamping device according to claim 2, wherein the coupling means has a hook-like portion at a tip end of the piston rod to be inserted into a concave portion of the pallet and projects from a cylinder in parallel with the piston rod.
A lock for holding the pallet in cooperation with the hook
A first piston cylinder member which is movable in horizontal direction toward a de, the interposed first piston cylinder member
Pressure to urge piston rod forward and said rod backward
Inserting the compression spring and the hook into the recess of the pallet
Therefore, the first piston cylinder member is moved up and down.
A second piston cylinder member that, said first piston cylinder unit after rise of the oil feeding oil pressure to the second piston cylinder member
2. The eccentric part processing pallet positioning pallet positioning mechanism according to claim 1, further comprising a hydraulic sequence circuit for feeding oil to the material and holding the pallet. 3. The eccentric part processing pallet positioning mechanism according to claim 2, wherein an air circuit is used in place of the hydraulic circuit.