JP7461820B2 - Work table - Google Patents

Description

This invention relates to a work table used in an automatic work exchange system in which a loader transports workpieces to a machine tool such as a lathe or multitasking machine, to store multiple workpieces so that they can be transferred to the loader in sequence.

When machining workpieces using a machine tool such as a lathe, an automatic workpiece exchange system is known that allows continuous machining of workpieces to be performed unmanned by stocking a large number of workpieces on a worktable installed adjacent to the machine tool and removing the workpieces one by one from the worktable using a loader that can move back and forth in the horizontal Z-axis direction and transporting them to the machine tool.

For example, as shown in Patent Documents 1 and 2, the work table is equipped with multiple pallets that can be moved along a predetermined circulation path so as to be sequentially indexed to a work transfer position where the work is transferred to and from the loader. Each pallet is equipped with a lift table that can be raised and lowered and has a work placement section on its upper surface, and multiple guide bars that extend vertically upward. The multiple workpieces placed in a stack on the work placement section are held by the multiple guide bars so that horizontal movement is restricted.

Here, when the workpiece being machined by the machine tool is changed to another type of workpiece having, for example, a different outer diameter, it becomes necessary to change and adjust the positions of the multiple guide bars relative to the workpiece mounting portion depending on the size of the workpiece.
In order to accommodate such setup changes, conventional work tables, as described in Patent Documents 1 and 2, for example, are provided with a mechanism on each pallet that horizontally moves multiple guide bars equal distances in the radial direction from the center of the lift table.

Japanese Utility Model Application Publication No. 6-42041 Japanese Patent Application Laid-Open No. 9-234644

In an automatic workpiece changing system, in order to increase the efficiency of workpiece processing by a lathe or the like, it is necessary to stock as many workpieces as possible on the worktable. For this reason, the worktable is usually equipped with 10 to 20 pallets.
However, with conventional work tables, the positions of all of the multiple guide bars on each pallet must be changed and adjusted when changing the setup, which requires a lot of time and effort, resulting in problems with work efficiency.

The object of this invention, which has been made in consideration of the above problems, is to provide a work table that can reduce the effort and time required for changeovers and improve work efficiency.

To achieve the above objective, this invention comprises the following aspects:

1) The present invention includes a plurality of pallets that can be moved along a predetermined circulation path so as to be sequentially indexed to a workpiece transfer position where the workpiece is transferred between the pallets and a loader that can reciprocate in a horizontal Z-axis direction;
Each of the plurality of pallets has a lift table that can be raised and lowered and has a work placement portion on an upper surface thereof, and three guide bars that face vertically upward and hold the work placed on the work placement portion so that horizontal movement of the work is restricted,
The three guide bars are a work table consisting of two fixed guide bars whose horizontal positions relative to the lift table are fixed, and one movable guide bar that is movable in a predetermined horizontal linear direction relative to the lift table during setup changeover.

2) The work table of 1) above, in which the horizontal positions of the three guide bars relative to the lift table and the linear direction of the movable bar are set so that the center of the work held by the three guide bars at the work transfer position is located on the Z axis along which the center of the work holder provided on the loader moves when viewed from a plane, regardless of the size of the work.

When using the work table described above in 1), when changing the setup, all that is required is to move one movable guide table of each pallet in a predetermined horizontal linear direction to change and adjust its position according to the size of the work to be changed, which significantly reduces the effort and time required for changeover compared to conventional technology and improves work efficiency.

According to the work table in 2) above, the center of the work held by the three guide bars at the work transfer position moves according to the size of the work, but when viewed from above, it is always located on the Z-axis along which the center of the work holder provided on the loader moves, so it is possible to respond to setup changes by changing the teaching point of the loader, making teaching work easy.

1 is a vertical sectional view showing an outline of an automatic workpiece changing system in which a worktable according to an embodiment of the present invention is combined with a lathe and a loader. FIG. 2 is a plan view of the automatic workpiece changing system. 13 is a plan view showing a pallet indexed to a workpiece transfer position on the work table. FIG.

An embodiment of the present invention will now be described with reference to FIGS.
In the following description, the left and right sides of each of Figs. 1 to 3 will be referred to as "left and right", the bottoms of each of Figs. 2 and 3 will be referred to as "front", and the tops of each of Figs. 2 and 3 will be referred to as "rear".

As shown in Figures 1 and 2, the work table (4) in this embodiment is combined with a lathe (2) and a loader (3) to form an automatic workpiece exchange system (1).

The lathe (2) has a spindle (21) and a tool rest (22) arranged in a machining chamber (20).
The spindle (21) is installed so as to be rotatable about a horizontal spindle axis extending in the left-right direction. A chuck (21a) for gripping a workpiece (W) is provided at the tip of the spindle (21).
The illustrated tool rest (22) is movable in the machining chamber (20) in the horizontal Z-axis direction (left-right direction) and in the X-axis direction perpendicular to the Z-axis direction, and a tool holder (22a) on which a plurality of tools can be mounted is provided so as to be rotatable about a horizontal rotation axis extending in the left-right direction.
An opening (23a) for inserting and removing the workpiece (W) is provided in an upper cover (23) covering an upper portion of the machining chamber (20). The opening (23a) is closed by a sliding door (24) during machining of the workpiece.

The loader (3) is a gate-shaped device that is installed above the lathe (2) and the work table (4) and includes a carrier (32) that is attached to a horizontal beam (31) that extends in the left-right direction and is movable back and forth, a vertical arm (33) that is attached to the carrier (32) and is movable up and down, and a work hand (34) (work holder) that is attached to the lower end of the arm (33) and detachably holds the work (W). The work hand (34) grips the work (W) with a chuck. It is also possible to use a work holder that attracts and holds the work (W) with, for example, an electromagnet instead of the work hand (34).
In the case of the loader (3) shown in the figures, two work hands (34) are attached to a rotating body (35) that can rotate about a rotation axis that is inclined 45° downward to the left at the lower end of the arm (33). The two work hands (34) are attached to the rotating body (35) so that one faces horizontally to the left on the main shaft (21) side and the other faces vertically downward, and the positions of both work hands (34) are interchanged by rotating the rotating body (35) by 180°.
The loader 3 described above can alternately transport the workpiece W before and after machining between the spindle 21 of the lathe 2 and a pallet indexed to the workpiece transfer position on the work table 4. During transportation, the center of the workpiece W held by each work hand 34 moves on the Z axis that coincides with the axis of the spindle of the lathe 2 when viewed from above.
It should be noted that the work table of the present invention is not limited to being combined with a two-axis loader (3) as shown in the figure, but can also be applied when combined with a one-axis loader capable of transporting a workpiece only in the Z-axis direction, or a three-axis loader capable of transporting a workpiece in the X-axis direction (front-back direction) in addition to the Z-axis and Y-axis directions.

The work table (4) is provided with a plurality of pallets (5) (ten in FIG. 2) that can be moved in a loop shape on a top plate (41a) of a base (41) that is long in the front-rear direction.
Each pallet 5 has a base plate 51 that is movable on the top plate 41a of the base 41. The base plate 51 can be configured to run on the top plate 41a, for example, by attaching wheels (not shown) to the bottom of the base plate 51.
Below the top plate (41a) of the base (41), there are arranged two sprockets (42), one in the front and one in the rear, which are rotatable about a vertical axis, and a chain (43) stretched around both sprockets (42). The base plate (51) of each pallet (5) is connected to the chain (43) at a predetermined interval via a connecting means (not shown). When one of the sprockets (42) is driven to rotate by a motor (not shown) or the like, the chain (43) is rotated in a horizontal plane, and the base plate (51) of each pallet (5) is moved along the circulation path (R) on the top plate (41a).
Each pallet (5) also has a lift table (52) that can be raised and lowered and has a workpiece mounting portion (52a) on its upper surface, and three vertically upward guide bars (531) (532) that hold the workpiece (W) placed on the workpiece mounting portion (52a) so that horizontal movement is restricted.
The three guide bars consist of two fixed guide bars (531) whose horizontal positions relative to the lift table (52) are fixed, and one movable guide bar (532) which is movable in a predetermined horizontal linear direction relative to the lift table (52) during changeover.
2, the front ends of the left and right straight portions of the circulation path (R) of the pallet (5) are workpiece transfer positions (P1) and (P2) where the workpiece (W) is transferred to and from the loader (3). Specifically, for example, at the right-side workpiece transfer position (P1), the unmachined workpiece (W) placed on the workpiece placement portion (52a) of the pallet (5) is taken out by one of the work hands (34) of the loader (3), and at the left-side workpiece transfer position (P2), the machined workpiece (W) held by the other work hand (34) of the loader (3) is returned to the workpiece placement portion (52a) of the pallet (5).

The lift table (52) is, for example, in the shape of a disk, and is disposed on the base plate (51).
A plurality of unmachined or machined workpieces (W) are placed in a stack on a workpiece placement surface (52a) of the lift table (52).

3, the lift table 52 is formed with three vertical insertion holes 521, 522 through which three guide bars 531, 532 are inserted so as to be movable vertically relative to each other. The lift table 52 is raised and lowered in the vertical direction while being guided by the guide bars 531, 532.
Of the three insertion holes in the lift table 52, the two insertion holes 521 through which the fixed guide bar 531 is inserted are generally circular holes having a diameter slightly larger than the outer diameter of the fixed guide bar 531. The remaining insertion hole 522 through which the movable guide bar 532 is inserted is an elongated hole extending in the linear motion direction of the movable guide bar 532. The movable guide bar 532 is allowed to move linearly within the length of the insertion hole 522.
In addition, instead of the two insertion holes (521a) through which the fixed guide bar (531) is inserted, the lift table (52) may have two arc-shaped cutouts formed in the outer periphery when viewed from above, and the two fixed guide bars (531) may be arranged to be relatively movable up and down in these cutouts. Also, instead of the elongated insertion holes (522) in the work table (52), a slit extending radially from the outer periphery to the center may be formed, and the movable guide bar (532) may be arranged in the slit so as to be linearly movable.

When each pallet (5) is indexed to the work transfer position (P1) (P2), the lift table (52) is raised and lowered by a lifting device (not shown) located below it, so that it can be moved to the required height suitable for the transfer of the work (W). The lifting device can have, for example, a vertical lifting rod (not shown) that penetrates the top plate (41a) of the base (41) and is driven to rise and fall by a driving device (not shown) such as a motor at the work index position (P1) (P2). The lift table (52) can be raised by raising the lifting rod and pushing up the lift table (52) with its upper end, and can be lowered by lowering the lifting rod.

The two fixed guide bars (531) have their lower ends fixedly attached to the base plate (51).
The movable guide bar (532) is attached so that its lower end can move linearly horizontally within a range corresponding to the length of the insertion hole (522) of the lift table (52), and its position can be changed or adjusted, for example, by a driving means such as a motor (not shown) arranged below the base plate (51), or manually.
Taking into consideration the attachment to the work hand 34 of the loader 3, it is preferable that each of the guide bars 531, 532 is made of a round bar having a circular outer periphery in cross section.

As shown in FIG. 3, the center (W1) of the workpiece (W) held by the three guide bars (531) and (532) at the workpiece transfer positions (P1) and (P2) is always located on the Z-axis (Z) along which the center of the workpiece hand (34) (workpiece holder) provided on the loader (3) moves when viewed from above, regardless of the size of the workpiece (W).
The centering of the workpiece (W) as described above can be achieved by appropriately setting the horizontal positions of the three guide bars (531) and (532) relative to the lift table (52) and the linear motion direction of the movable guide bar (532) . More specifically, as shown in Fig. 3, the two fixed guide bars (531) are arranged so that when the pallet (5) is indexed to the workpiece transfer positions (P1) and (P2 ) , a straight line (L1) connecting their centers as viewed from above is perpendicular to the Z-axis (Z) at the center of the length of the straight line (L1). In addition, when the pallet (5) is indexed to the workpiece transfer positions (P1) and (P2), the center of the movable guide bar (532) is located on the Z-axis (Z) as viewed from above, and the linear motion direction is aligned with the Z-axis (Z).
When positioning the three guide bars (531) (532) , first, the outer periphery of the workpiece (W) is brought into contact with the two fixed guide bars (531) , and then the movable guide bar (532) is moved in the linear direction to bring it into contact with the outer periphery of the workpiece (W), thereby holding the center of the workpiece (W). Also, by changing the teaching point of the loader (3) according to the size of the workpiece (W), centering can be performed, making teaching work easy.

This invention is suitable for use as a work table in combination with a machine tool such as a lathe and a loader to create an automatic workpiece exchange system.

(1): Automatic workpiece exchange system
(2) : Lathe (machine tool)
(20) Processing room
(21): Main shaft
(22): Tool holder
(3): Loader
(32): Career
(33): Arm
(34): Work hand (work holder)
(4): Work table
(5) Palette
(52): Lift table
(52a): Workpiece placement section
(531): Fixed guide bar
(532): Movable guide bar

Claims (1)

The present invention provides a method for manufacturing a workpiece loading machine comprising: a loader that is movable in a horizontal Z-axis direction; a plurality of pallets that can be moved along a predetermined circulation path so as to be sequentially indexed to a workpiece transfer position where the workpiece is transferred between the loader and the loader;
Each of the plurality of pallets has a lift table that can be raised and lowered and has a work placement portion on an upper surface thereof, and three guide bars that face vertically upward and hold the work placed on the work placement portion so that horizontal movement of the work is restricted,
The three guide bars include two fixed guide bars whose horizontal positions relative to the lift table are fixed, and one movable guide bar that is movable in a predetermined horizontal linear direction relative to the lift table during a changeover,
A work table in which the horizontal positions of the three guide bars relative to the lift table and the linear direction of the movable guide bar are set so that the center of the work held by the three guide bars at the work transfer position is located on the Z axis along which the center of the work holder provided on the loader moves when viewed from a plane, regardless of the size of the work.

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