JPH07266187A - Positioning mechanism for eccentric part machining pallet - Google Patents

Abstract

PURPOSE:To perform the positioning of a workpiece for turning an eccentric part of this workpiece easily and automatically in a short time by installing a connecting means, connecting a pallet free of tripping motion, in a column and a braking member, being free of tripping to check any motion in the orthogonal direction, in a turning axis of this connecting member, respectively. CONSTITUTION:A pallet 7 attached with a workpiece is carried in on top of a turntable and, after being clamped by a clamp plate, this turntable is rotated and turning work tales place. Subsequently the clamp is released and the pallet 7 is pinched by a hook part 20 of a pinching device and a rod 24, and this pinched state is maintained by a braking member 22. In this state intact, a column 4 is moved and the pallet 7 is traveled up to a specified position on the table. Next, the pinch by the braking member 22 is released, and clamping takes place again. Afterward the turntable is rotated again, whereby turning work is applied to an eccentric position.

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 having a workpiece attached thereto into a machine tool, rotating the workpiece together with the pallet, and performing turning even at an eccentric position of the workpiece.

[0002]

2. Description of the Related Art For example, in order to attach a workpiece 32 having an eccentric portion shown in FIG. 4 to a pallet and perform turning at an eccentric position as well, the pallet with the workpiece (material) attached is carried onto a rotary table. , The center line 34 of the workpiece (material) and the center line of rotation of the rotary table are aligned. In this state, the rotary table is rotated to turn the predetermined portion 33 of the workpiece.

Next, the operator removes the workpiece from the pallet, repositions the center 37 of the portion to be eccentric to the rotation center of the rotary table, and reattaches the workpiece to the pallet. Thereafter, the desired eccentric cylindrical portion 36 is subjected to turning. When reattaching the work, another pallet prepared for the setup may be used by using a loader or the like.

[0004]

When a work piece is fixed to a pallet and carried into a machine tool, the shape of the work piece is special and complicated, and it is often difficult to hold the work piece by a general chuck. In many cases, automation cannot be performed if only the workpiece is handled. Such a workpiece requires a lot of time and setup to be mounted on the pallet, which not only increases the ratio of the mounting time to the pallet to the total working time, but also causes the eccentric portion as described in the prior art. Reattaching the work piece for turning has a problem of adversely affecting time and cost.

The present invention automatically moves the pallet when performing turning on the eccentric part of the workpiece mounted on the pallet, thereby shortening the time required for changing the machining position and changing the position. The purpose is to reduce the cost of the product by eliminating the need for dedicated setup.

[0006]

In order to achieve the above object, the eccentric part machining pallet positioning mechanism of the present invention is detachably attached by a clamp member capable of tightening and loosening a pallet on which a workpiece is placed. A rotary table rotatable about a rotation axis in the vertical direction and a column having a spindle head movable in the vertical direction are provided so as to be able to move relative positions in a direction perpendicular to the rotation axis, and to the spindle head. 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 hung and removed freely, and the movement of the connecting means in a direction perpendicular to the rotation axis is blocked. A braking member that can be applied and removed freely is provided, and the pallet is connected to the column by the connecting means, and the rotary table is rotated by 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-shaped portion for inserting into a recess of the pallet at the tip of the piston rod, and the cylinder is movable in a direction perpendicular to the rotation axis of the rotary table, which is movable in the horizontal and vertical directions. A first piston cylinder member, a second piston cylinder member fixed to the cylinder of the first piston cylinder member and abutting the outer periphery of the pallet to sandwich the pallet with the hook-shaped portion, the first piston cylinder member, And a hydraulic circuit for driving the second piston cylinder member.

An air circuit is used instead of the hydraulic circuit.

[0009]

[Operation] The pallet with the work is mounted on the rotary table, and after the clamp, the rotary table is rotated to perform turning. After that, 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 clamp it again. After this, the rotary table is rotated again to perform turning at the eccentric position.

[0010]

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. A saddle 2 is movably mounted horizontally on the front side of a T-shaped base 1 in the X-axis direction. A rotary table 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 horizontally movable in the Y-axis direction, and a spindle head 5 is movably attached to the front surface of the column 4 vertically in the Z-axis direction. At the bottom of the spindle head 5 is a spindle 6 for tool mounting.
Is provided.

FIG. 2 shows a device for fixing the pallet 7 to the rotary table 3, in which a hollow rotary shaft 8 is supported perpendicularly to 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 drive source (not shown). A clamp shaft 10 is attached to the pallet 7 so as to be vertically movable at the center of a rotary shaft 8 having a hollow cross section that opens downward, and the pallet 7 is inserted into the groove of the pallet 7 at the upper end of the clamp shaft 10. A clamp plate 11 that presses against the rotary table 3 is fixed.

The upper surface of the clamp plate 11 has a pallet 7
A roller 12 for contacting the bottom surface of the groove to smoothly move the pallet 7 is attached. Clamp shaft 10
A piston cylinder member 13 for pallet clamp is attached to the lower end of the clamp shaft 10 and the clamp shaft 10 and the clamp plate 11 are raised. Further, a disc spring 14 for pushing down the clamp shaft 10 and the clamp plate 11 is interposed between the hollow rotary shaft 8 and the clamp shaft 10.

FIG. 3 shows a pallet holding device for repositioning the pallet 7 carried on the rotary table 3. The window 1 is located at the position facing the pallet 7 on the front surface of the column 4.
5 is provided. A vertical guide 4a is provided inside the column 4, and a holding device main body 16 is provided on the guide 4a so as to be vertically movable, and a lower end of the main body 16 is provided in the column 4 and extends vertically upward. 2 piston cylinder member 17
It is connected to the piston rod of. Inside the main body 16, 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.

The front piston rod 19 of the first piston cylinder member 18 projects from the window 15 toward the outer pallet side, and the tip 20 is bent upward in a hook shape. Further, the rear piston rod 21 of the first piston cylinder member 18 is adapted to be braked by a braking device 22 which stops the movement of the piston so as to be freely detachable. Cylinder 2 of the first piston cylinder member 18
3, the rod 24 projects outward from the window 15 in parallel with the piston rod 19. A compression spring 25 is attached to the rear chamber of the cylinder 23 and always urges the piston rod 19 to move forward and the rod 24 to move backward.

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

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

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 to press the pallet 7 against the rotary table 3 to clamp it. Thereafter, when the rotary shaft 8 is rotated by a drive source (not shown), the rotary table 3
At the same time, the pallet 7 rotates and the turning work is carried out by the tool attached to the main shaft 6 to carry out the turning work of the cylindrical portion 33 around the center line 34.

After the turning of the cylindrical portion 33 is completed, the rotary table 3 is rotated by a drive source (not shown) to align the groove direction of the pallet 7 with the Y-axis direction. In this state, move column 4 to Y
By axially advancing, the tip hook 20 of the piston rod 19 and the recess 35 formed in the ceiling portion of the pallet 7 are aligned in the Z-axis direction. Then, the 3-position switching solenoid valve 28 is switched to the a position and the 2-position switching solenoid valve 31 is switched to the d position at the same time, and the lower chamber 26a of the cylinder 26 of the second piston cylinder member 17 is pumped through the 3-position switching solenoid valve 28. Send pressure oil.

At this time, the pressure oil to the branch flow passage is supplied to the check valve 3
Oil supply is stopped with a spring force of 0. 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 its tip abuts the ceiling of the concave portion, the main body 16 is prevented from rising and the inside of the cylinder lower chamber 26 is blocked. The pressure of the oil increases, and the pressure oil is sent from the branch flow passage to the front chamber 29 of the cylinder 23 through the two-position switching solenoid valve 31 against the spring force of the check valve 30.

When pressure oil is sent to the front chamber 23a of the cylinder 23, the piston rod 19 and the tip hook portion 20 are compressed by the compression spring 25.
And retracts, and the tip hook contacts the rear wall in the recess 35 of the pallet 7. At the same time, the cylinder 23 and the rod 24 advance toward the main body 16 and the tip of the rod 24 moves to the pallet 7.
Abut the outer wall of. That is, the pallet 7 is clamped by the hook portion 20 and the rod 24. In this state, the rear piston rod 21 is immovably gripped by the braking device 22, and the sandwiched state of the pallet 7 is maintained.

Pressure oil is sent to the cylinder lower chamber of the piston cylinder member 13 to raise the piston, the rotary shaft 8 and the clamp plate 11 to release the clamp of the pallet 7. Following the rise of the pallet 7 at the time of this clamping, the main body 16 rises together with it, and the signal for releasing the pallet clamp switches the 3-position switching solenoid valve 28 to the C position, closing the lower chamber 26a of the cylinder 26 and closing the main body 16 of the main body 16. Prevent the descent.

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, and the center line 37 of the second cylindrical portion 36 is aligned with the center line of the rotary table 3 for positioning. And 3 position switching solenoid valve 2
After switching 8 to the b position to enable the lowering of the holding device body 16, the pallet 7 is clamped on 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 electromagnetic valve 31 is switched to the e position, the action of the compression spring 25 causes the piston to move forward and at the same time the cylinder 23 to retract, The clamping of the pallet 7 is released, which causes the cylinder lower chamber 26
The oil inside is discharged into the tank 38, and the holding device body 16 descends by its own weight. Then, the eccentric cylindrical portion 36 is subsequently turned.

By setting the groove width of the groove having a T-shaped section provided on the pallet 7 to be larger than the clamp plate 11 with a margin, the saddle 2 is moved to the X position while the pallet is clamped after the unclamping. If it is moved to the axis, the eccentric turning machining can be performed on a center line other than the plane including the two center lines 34, 37.

Further, although the machine tool of the type in which the column 4 moves in the Y-axis has been described in this embodiment, it is also applicable to the machine tool of the type in which the column 4 is fixed and the rotary table 3 is movable in the Y-axis. Of course, of course.

[0026]

The advantage of the first aspect is that the positioning of the workpiece for turning the eccentric portion of the workpiece can be easily and automatically performed in a short time.

Since the pallet holding portion is composed of the piston cylinder itself, the pallet holding portion does not require an operating member for holding the pallet, and the structure is simple and the cost is low.
In addition, since the hydraulic circuit is a fluid sequence circuit, confirmation means for each operation is not required, and the structure is simple and the cost is low.
Further, since the hydraulic circuit is a fluid sequence circuit, confirmation means for each operation is not required, and the structure is simple and the cost is low.

With respect to the third aspect, since the hydraulic circuit is replaced by the air circuit, there is no fear of oil leakage and the cost is reduced.

[Brief description of drawings]

FIG. 1 is an overall perspective view of a vertical machining center of this embodiment.

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

FIG. 3 is an explanatory diagram 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 the conventional technique.

[Explanation of symbols]

1 T-type base 2 Saddle 3 Rotating table 4 Column 7 Pallet 11 Clamp plate 16 Clamping device 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)

[Claims] 1. A rotary table, which is removably mounted around a vertical axis of rotation, which is detachably attached by a clamp member capable of tightening and loosening a pallet on which a workpiece is placed, and a spindle head which is movable in the vertical direction. A column having a column that is movable relative to the axis of rotation in a direction perpendicular to the axis of rotation, and a machine tool for turning a workpiece on a pallet with a tool attached to the spindle head. .Providing a connecting means for connecting in a freely detachable manner, and providing a breaking member for preventing the movement of the connecting means in a direction perpendicular to the rotation axis, and providing a detachable braking member, and connecting the pallet to the column by the connecting means to form a rotary table. An eccentric part machining pallet characterized by positioning the pallet at an arbitrary position on the rotary table in a direction perpendicular to the rotation axis by relative movement between columns. Positioning mechanism. 2. The connecting means is a pallet holding device, which has a hook-shaped portion to be inserted into a concave portion of the pallet at a tip of a piston rod, and the cylinder is perpendicular to a rotation axis of a rotary table which is movable in horizontal and vertical directions. A first piston cylinder member in different directions, a second piston cylinder member fixed to the cylinder of the first piston cylinder member and abutting the outer periphery of the pallet to sandwich the pallet with the hook-shaped portion, and the first piston cylinder 2. The eccentric part machining pallet positioning mechanism according to claim 1, comprising a member and a hydraulic circuit for driving the second piston cylinder member. 3. The eccentric part machining pallet positioning mechanism according to claim 2, wherein an air circuit is used in place of the hydraulic circuit.