JPH08155776A - Pallet changing device in machine tool - Google Patents

Abstract

PURPOSE: To provide a pallet changing device in a machine tool capable of minimizing the number of actuators to a necessary minimum and simplifying the structure of a pallet table. CONSTITUTION: When a pallet is changed, the pallet Pa is positioned on a pallet table 15, and a clamp is released by a pallet clamping device 31, and separated from the pallet table 15 by a pallet elevating device 47. Then, a fork Fa is advanced between the pallet Pa and the pallet table 15 to position and load the pallet Pa on the fork Fa. The fork Fa on which the pallet Pa is loaded is moved to a pallet stocker by sliding a plurality of rollers 19 provided on a frame 1 on a guide surface 15a.

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 for exchanging pallets between a pallet stocker and a pallet table on a machine tool.

[0002]

2. Description of the Related Art Generally, when machining of a work is finished by a machine tool, a pallet with a machined work is removed from a pallet table of the machine tool by a pallet exchanging device, and a pallet stocker provided outside the machine tool. Then, the pallet, which is placed on another pallet stocker provided outside the machine tool and has the other workpieces already set up, is newly loaded onto the pallet table of the machine tool by the pallet changer. Replace the pallet.

As an example of the pallet exchanging device, there is a pallet exchanging device for machine tools as disclosed in the specification of Japanese Patent Application No. 5-247109 filed by the present applicant. When pallets are carried out from the pallet table of the machine tool to the pallet stocker provided outside the machine tool, this device first releases the pallet clamp means for positioning and fixing the pallet, and then the pallet lifting means moves the pallet up and down. The rail is lifted and separated from the pallet table, and the rail as the pallet supporting means provided on the pallet table is lifted by the rail elevating means so that the rail and the pallet stocker are aligned in height. After that, the pallet is lowered by the pallet elevating means and supported on the rail, and the pallet is moved on the pallet stocker so as to slide on the plurality of rollers provided on the rail and the pallet stocker. When loading a pallet from another pallet stocker provided outside the machine tool to the pallet table, move the new pallet onto the pallet table by sliding it on the rollers provided on the pallet stocker and rails. . After that, when the pallet is supported on the rail, the pallet elevating means raises the pallet from the rail once and removes it from the rail, and the rail elevating means lowers and retracts the pallet. The pallet clamp means is moved down to operate and position and fix it on the pallet table.

[0004]

However, in the above apparatus, when the pallet stocker and the pallet table of the machine tool are exchanged, the rail that is the pallet supporting means provided on the pallet table is raised, Since the pallet is moved by aligning the height positions of the rail and the pallet stocker, the pallet table must be provided with a pallet elevating means for separating the pallet from the pallet table and a rail elevating means for elevating the rail. Structure becomes complicated. Also, chips generated by processing may scatter, and chips may accumulate on a plurality of rollers provided on the pallet stocker and the rails and between each roller.When the pallet moves on the rollers, the pallet and the rollers are separated from each other. There is a problem that chips get caught in between, which hinders the rotation of the roller and prevents the smooth movement of the pallet. Therefore, the present invention is
The number of actuators such as pistons and cylinders is minimized to simplify the structure of the pallet table, and the pallet can be moved smoothly between the pallet stocker and the pallet table of the machine tool without being affected by chips. An object of the present invention is to provide a pallet changing device for machine tools.

[0005]

In view of this object, the present invention has the respective constituent features described below. (1) In a pallet exchanging device of a machine tool for exchanging pallets between a pallet stocker and a pallet table on a machine tool, positioning means for positioning the pallet at a predetermined position on the pallet table, and positioning by the positioning means. Pallet clamp means for detachably fixing the pallet to the pallet table, pallet elevating means for elevating and lowering the pallet to engage and disengage with the positioning means, a frame for mounting the pallet, and a pallet mounted on the frame. And a fork member configured to position the pallet when the pallet is exchanged, and to move between the pallet stocker and the pallet table together with the pallet, and a positioning pin that positions the pallet and a plurality of rollers rotatably attached to the frame. , The pallet stocker and the Guide means provided across the pallet table and for guiding the movement of the fork member between the pallet stocker and the pallet table;
A fork member drive means for moving the pallet and the fork member along the guide means, and the fork member so as not to drop from the pallet stocker,
A pallet exchanging device for a machine tool, comprising: fork member locking means for locking the fork member to the pallet stocker. (2) The item (1) above, wherein the fork member includes cleaning means for cleaning the guide surface of the guide means as the fork member moves between the pallet stocker and the pallet table. Machine tool pallet changer.

[0006]

With the above structure, when the pallet is replaced, the pallet clamp means is unclamped to release the positioning and fixing of the pallet on the pallet table of the machine tool, and the pallet lifting means lifts the pallet from the pallet table. A fork member is inserted between the pallet and the pallet table, the pallet elevating means lowers the pallet to the fork member, and the locating pin positions and places the pallet on the frame. After that, a fork member on which the pallet is positioned and placed by the fork member drive means is slid on a guide surface of a guide means provided by a plurality of rollers provided on the fork member across the pallet table and the pallet stocker. And move to the pallet stocker. At this time, the cleaning means provided on the fork member cleans the guide surface of the guide means as the fork member moves between the pallet stocker and the pallet table. Then, the fork member is locked to the pallet stocker by the fork member locking means. Remove the machined work from the pallet locked to the pallet stocker together with the fork member, attach the preprocessed work to the pallet, and position the pallet with the new work on the pallet table through the reverse path to the above.
Clamp to complete a series of pallet changing operations.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view of a pallet table at the time of pallet exchange of a machine tool equipped with the pallet exchange device of the present invention, and FIG. 2 is at the time of pallet exchange of a machine tool provided with the pallet exchange device of the present invention. 3 is a plan view of a pallet table in FIG. 3, FIG. 3 is a plan view showing a machine tool equipped with the pallet changing device of the embodiment of the present invention, and FIG.
FIG. 5 is a front view showing a machine tool equipped with the pallet changing device of the embodiment of the present invention, FIG. 5 is an operation explanatory view showing an outline of pallet changing of the pallet changing device of the machine tool of the present invention, and FIG. It is a flowchart which shows the operation sequence of the pallet exchange of the pallet exchange apparatus of a machine.

First, referring to FIGS. 3 and 4, a machine tool having a pallet changing device according to an embodiment of the present invention will be described. The machine tool 53 is provided with an X-axis guide surface 55 on the front of the bed 27, and is provided with a pallet clamp device 31 for positioning and fixing the pallet P by the taper cone 29, and a pallet lifting device 47 for lifting the pallet P. The pallet table 15 moves on the X-axis guide surface 55 in the X-axis direction. A Z-axis guide surface 57 is provided behind the bed 27, and a column 59 standing on the bed 27 moves on the Z-axis guide surface 57 in the Z-axis direction. A Y-axis guide surface (not shown) is provided on the front surface of the column 59, and a spindle head 63 that rotatably supports a spindle 61 on which a tool is mounted moves in the Y-axis direction on the Y-axis guide surface. It should be noted that pallet stockers 5 and 5 on which pallets Pa and Pb are placed are arranged adjacent to each other on both outer sides of the bed 27 of the machine tool 53.

3 and 4 show a pallet table 15
It shows a state when the pallet table 15 is moved to a pallet exchange position where the pallet Pa placed on the pallet stocker 5 on the left side of the machine tool 53 is carried out, and the fork Fa is in front of the bifurcated frame 1. The portion is locked on the pallet stocker 5 such that the rear portion of the chain rack 3 provided on the frame 1 is sandwiched by the stopper 65 and the stopper portion 5b of the pallet stocker 5. A limit switch (not shown) is built in the stopper portion 5b of the pallet stocker 5 so that the fork F moves from the pallet table 15 onto the pallet stocker 5 and the chain provided on the frame 1 of the fork F is moved. When the limit switch is turned on by the rear portion of the rack 3, the stopper 65 rises from the inside of the pallet stocker 5 to the front portion of the bifurcated frame 1 to sandwich the fork F.

A positioning pin 3 for positioning and placing the pallet P on the upper surface of the frame 1 of the fork F.
5 are provided at the four corners, and six rollers 19 are rotatably attached to the lower surface of the frame 1, and when the fork 1 is moved, on the guide surface 5a of the upper surface of the pallet stocker 5 and the upper surface of the pallet table 15. Of the pallet stocker 5 and the side surfaces of the pallet table 15 at the same time. The six side rollers 13 are rotatably attached to the side surfaces of the frame 1, respectively. The movement of the fork F is guided so as to slide between and. Further, as the fork F moves, the wiper 6 provided before and after the plurality of rollers 17 mounted on the lower surface of the frame 1 is sandwiched therebetween.
7, the cleaning is performed on the guide surface 5a on the upper surface of the pallet stocker 5 and on the guide surface 15a on the upper surface of the pallet table 15.

The fork F is moved between the pallet stocker 5 and the pallet table 15 by tensioning a chain rack 3 provided on the frame 1 of the fork F and the pallet stocker 5 with a pair of idlers 69, 69 at both ends. The endless chain 7 provided so as to be installed always meshes with each other, and among the three sprockets 71 provided at the central portion of the endless chain 7 so as to mesh with the endless chain 7, a chain drive motor ( By driving (not shown), the chain rack 3 is rotated together with the endless chain 7. Machine tool 5
The pallet stocker 5 arranged on the outer right side of the pallet 3 also has the same structure as the pallet stocker 5 arranged on the outer left side, and the upper surface of the frame 1 of the fork Fb fixed on the pallet stocker 5 The pallet Pb is positioned and placed by the positioning pins 35 provided at the four corners.

Next, with reference to FIGS. 1 and 2, description will be given of a pallet table and its surroundings when a pallet is to be replaced in a machine tool equipped with a pallet changing device according to an embodiment of the present invention. FIG.
And FIG. 2 shows that the endless chain 7 meshed with the chain rack 3 provided on the frame 1 of the fork Fa is rotated and the blocks 9 attached to both side portions of the frame 1 are rotated.
A side roller 13 rotatably attached via a shaft 11 provided on the sliding surface slides between both side surface portions of the pallet stocker 5 and both side surface portions of the pallet table 15 and rotates via a shaft 17 provided on the lower surface portion of the frame 1. The freely mounted roller 19 slides between the guide surface 5a on the upper surface of the pallet stocker 5 and the guide surface 15a on the upper surface of the pallet table 15, and the fork Fa moves from the pallet stocker 5 to the pallet table 15. The pallet Pa is then positioned between the pallet Pa and the pallet table 15, and the pallet Pa is positioned and placed on the fork Fa.

Pull stud bolts 21 for fixing pallets are screwed into every other 12 equally spaced locations on the same circumference of the bottom surface of the pallet P so that the pull stud bolts 21 penetrate and project through the center. A locate bush 23 having a tapered hole is provided in each of the pull stud bolts 21, and a support bush 25 having a tapered hole is embedded between the pull stud bolts 21 like the locate bush 23. On the other hand, at a position corresponding to the pallet P on the upper surface of the pallet table 15 moving on the bed 27, the taper cone 29 that fits into the taper hole of the locate bush 23 to position the pallet P and the pull stud bolt 21 are pulled in. , And a pallet clamp device 31 for fixing the pallet P on the pallet table 15 are provided coaxially. further,
Positioning bushes 33 having tapered holes are provided at the four corners of the lower surface of the pallet P, and the frame 1 of the fork F is
Positioning pins 35 for fitting the tapered holes of the positioning bush 33 to position the pallet P are provided at positions corresponding to the pallet P on the upper surface.

The pallet clamp device 31 includes a plurality of balls 37 arranged in a ring shape, and has a pull stud bolt 2
Cylindrical ball collet portion 39 that engages with 1 in a retractable manner
A piston 39 provided with a at the tip thereof is adapted to move up and down translationally in a cylindrical cylinder 41. When positioning and placing the pallet P on the fork F, first
By switching the hydraulic pressure switching valve (4 port valve) 43, hydraulic oil is supplied from the hydraulic pressure source (P port) to the cylinder head side, the hydraulic oil on the cylinder rod side is collected in the tank (T port), and the piston 39 is raised. Let When the piston 39 rises, the balls 37 arranged in the ball collet portion 39 a at the tip of the piston 39 and the inner circumferential groove 29 of the taper cone 29.
The ball 37 is radiated outward in the inner circumferential groove 29a of the taper cone 29 at the same height position as a, and the pull stud bolt 21 extending so as to pass through the ring-shaped ball 37 is unclamped. Becomes Further, when positioning and fixing the pallet P on the pallet table 15, the hydraulic oil is supplied from the hydraulic pressure source (P port) to the cylinder rod side by another switching of the first hydraulic pressure switching valve 43, and the cylinder head side. Is collected in the tank (T port) and the piston 39 is lowered. When the piston 39 descends, the ball 3 moves from the inner circumferential groove 29a of the taper cone 29.
7 is pushed radially inward and pull stud bolt 21
The pull stud bolt 21 is engaged with the hooking portion 21a of the above and the pull stud bolt 21 is pulled downward to be in a clamped state.

The upper surface of the pallet table 15 corresponding to the support bush 25 embedded in the lower surface of the pallet P is fitted into the tapered hole of the support bush 25,
A pallet elevating device 47 having a piston 45 having a tapered tip end portion so as to restrain the movement of the pallet P in the plane is provided.
It is slidably mounted in a cylindrical cylinder 49 embedded in the. When the fork F is moved between the pallet P and the pallet table 15 and retracted, the second hydraulic pressure switching valve 51 is switched to supply hydraulic oil from the hydraulic pressure source (P port) to the cylinder head side to move the cylinder rod. Side hydraulic oil is collected in the tank (T port) and the piston 45 is raised. Further, when the pallet P is positioned on the fork F, placed, and positioned and fixed on the pallet table 15, another switching of the second hydraulic pressure switching valve 51 operates from the hydraulic pressure source (P port) to the cylinder rod side. By supplying oil, the working oil on the cylinder head side is collected in the tank (T port) and the piston 45 is lowered.

Referring to FIG. 2, the hydraulic oil supply piping path for raising the piston 45 to the cylinder head side is
A shunt / collector valve V for synchronously controlling both going and returning steps of the cylinder 49 of the pallet lifting device 47 is provided. Three shunt flow valves V are provided, and there are six pallet lifting devices 4
In FIG. 7, one diverter valve (Va, Vb, Vc) is assigned to each set of two pallet lifting devices (47a, 47b, 47c) located at 180 degrees opposite to each other, and the two pallet lifting devices are lifted. The pistons 45 in the device 47 coincide with each other in vertical movement speed, and the pistons 45 opposed to each other by 180 degrees move up and down in synchronization with each other.
Does not tilt. It should be noted that another new branching / collecting valve may be provided in the hydraulic oil supply pipe path so that the assembling of the pallet lifting / lowering devices 45 are mutually synchronized so that the pallet lifting / lowering device 45 is entirely synchronized. it can. The same effect can be obtained by combining a plurality of flow dividing valves that synchronize only the going process of the cylinder 49.

3 and 4 based on the mechanical structure of the pallet exchanging device for machine tools according to the embodiment of the present invention described above.
The process of pallet exchange from pallet Pa to pallet Pb will be described with reference to FIGS. 5 and 6. First,
As shown in FIG. 5A, the pallet table 15 is moved to the pallet exchange position where the pallet Pa positioned and clamped on the pallet table 15 is carried out to the pallet stocker 5 on the left side outside the machine tool 53 (step S1). Unpallet the pallet clamp device 31 to pallet P
Positioning and fixing of the tape a on the pallet table 15 by the taper cone 29 are released (step S2), the pallet elevating device 47 is operated to raise the piston 45, and the pallet Pa is moved.
From the pallet table 15 (step S
3).

Further, as shown in FIG. 5 (b), the fork Fa on the pallet stocker 5 on the left side of the machine tool 53 is inserted between the pallet Pa and the pallet table 15 (step S4) to raise and lower the pallet. The device 47 is operated to lower the piston 45, and the pallet Pa is positioned and placed on the fork Fa by the positioning pin 35 (step S
5) Then, the pallet Pa is carried out from the pallet table 15 onto the pallet stocker 5 together with the fork Fa (step S6). When the fork Fa moves onto the pallet stocker 5 and the rear portion of the chain rack 3 provided on the frame 1 turns on the limit switch attached to the stopper portion 5b of the pallet stocker 5, as shown in FIG. The stopper 65 rises from the inside of the pallet stocker 5 to the front part of the frame 1 (step S7) and locks the fork Fa so as not to move back and forth.

Next, the pallet table 15 is moved to the pallet exchange position where the pallet Pb is carried into the pallet table 15 from the pallet stocker 5 on the right side outside the machine tool 53 (step S8). Pallet P with fork Fb
b is loaded from the pallet stocker 5 onto the pallet table 15 (step S9), the pallet elevating device 47 is operated to raise the piston 45, and the pallet Pb is moved to the fork F.
It is disengaged from above b (step S10). The fork Fb is retracted from between the pallet Pb and the pallet table 15 onto the pallet stocker 5 (step S11), the pallet lifting device 47 is operated, and the piston 45 is lowered (step S11).
12), the pallet clamp device 31 is clamped to move the pallet Pb onto the pallet table 15 by the taper cone 29.
Are positioned and fixed by (step S13).

[0020]

As is apparent from the above description, according to the present invention, the fork member is inserted between the lifted pallet and the pallet table, and the pallet is moved together with the fork member between the pallet stocker and the pallet stocker. Since this is done, it is possible to omit the actuator that is the rail elevating means compared to the prior art, and the structure of the pallet table can be simplified. Further, by providing a roller on the fork member side so as to slide on the guide surface of the guide means and by providing a cleaning means, the movement of the pallet between the pallet stocker and the pallet table of the machine tool is affected by chips. Can be done smoothly without The pallet exchanging device for machine tools of the present invention is particularly suitable for exchanging heavy pallets.

[Brief description of drawings]

FIG. 1 is a side sectional view of a pallet table at the time of pallet exchange of a machine tool including a pallet exchange device according to an embodiment of the present invention.

FIG. 2 is a plan view of a pallet table at the time of pallet exchange of a machine tool including the pallet exchange device of the embodiment of the present invention.

FIG. 3 is a plan view showing a machine tool including the pallet changing device according to the embodiment of the present invention.

FIG. 4 is a front view showing a machine tool including a pallet changing device according to an embodiment of the present invention.

FIG. 5 is an operation explanatory view showing the outline of pallet exchange of the pallet exchange device for a machine tool of the present invention.

FIG. 6 is a flowchart showing an operation sequence of pallet exchange of the pallet exchange device for a machine tool of the present invention.

[Explanation of symbols]

 F, Fa, Fb Fork P, Pa, Pb Pallet 1 Frame 3 Chain rack 5 Pallet stocker 5a Guide surface 5b Stopper part 7 Endless chain 13 Side roller 15 Pallet table 15a Guide surface 19 Roller 21 Pull stud bolt 29 Tapered cone 31 Pallet clamp device 35 Positioning Pins 47, 47a, 47b, 47c Pallet Lifting Device 65 Stopper 67 Wiper

Claims (2)

[Claims] 1. A pallet exchanging device for a machine tool for exchanging pallets between a pallet stocker and a pallet table on a machine tool; positioning means for locating the pallet at a predetermined position on the pallet table; and positioning by the locating means. Pallet clamp means for removably fixing the pallet to the pallet table, pallet elevating means for elevating and lowering the pallet to engage and disengage with the positioning means, a frame on which the pallet is placed, and a frame mounted on the frame A fork that comprises a positioning pin for positioning the pallet and a plurality of rollers rotatably attached to the frame, mounts the pallet when replacing the pallet, and moves with the pallet between the pallet stocker and the pallet table. Member and the pallet strike Guide means provided across the pallet and the pallet table, and guiding the movement of the fork member between the pallet stocker and the pallet table; and moving the pallet and the fork member along the guide means. A pallet changer for a machine tool, comprising: fork member driving means, and fork member locking means for locking the fork member to the pallet stocker so that the fork member does not fall off the pallet stocker. apparatus. 2. The fork member according to claim 1, further comprising a cleaning unit that cleans a guide surface of the guide unit as the fork member moves between the pallet stocker and the pallet table. Machine tool pallet changing device.