A first embodiment of the present invention will be described with reference to
The tool supports 2, 3 comprise an upper turret and a lower turret, respectively, which are concentrically installed and have punch press tools 6 and die press tools 7, respectively, mounted at a plurality of positions in a circumferential direction. Rotation of the tool supports 2, 3 indexes each of the press tools 6, 7 to a predetermined press working axis center P.
The workpiece feeding mechanism 4 has a workpiece holder 8 that grips an edge of a workpiece W that is a plate material to move the workpiece W forward, backward, rightward, and leftward on a table 9.
The press driving mechanism 5 comprises a first linear motor 11 and a second linear motor 12 installed immediately below the first linear motor 11, as a press driving source. Output shafts of the first linear motor 11 and the second linear motor 12 are releasably coupled together by a coupling switching mechanism 13. A ram 14 is coupled to the output shaft of the second linear motor 12 to allow the punch press tool 6 to be lowered for a press working. The press tool 6 may be elevated and returned by a spring member (not shown in the drawings) or may be forcibly lifted by the ram 14.
As shown in
As shown in
The unit linear motor case 27 is fixed to a general motor frame 26 so that the coil unit 24 of each unit linear motor 15 constitutes a motor stator for the first linear motor 11. The coils 25 of the coil units 24 of the individual unit linear motors 15 may be installed in one common general motor frame 26 without providing the individual unit linear motor cases 27.
One ends of the shaft member 23 of the unit linear motors 15 are coupled together by an upper output shaft coupling frame 28, and other ends of the shaft member 23 of the unit linear motors 15 are coupled together by a lower output shaft coupling frame 29. An output shaft 30 (
Like the first linear motor 11, the second linear motor 12 comprises a unit linear motor assembly of a plurality of unit linear motors 15 arranged around the press working axis center P. The number of unit linear motors 15 in the second linear motor 12 is set equal to or greater than that in the first linear motor 11 and is two in the illustrated example. The configuration of the unit linear motor 15 of the second linear motor 12 is the same as that of the unit linear motor 15 of the first linear motor 11, described above with reference to
The unit linear motor case 27 is fixed to a general motor frame 31 so that the coil unit 24 of each unit linear motor 15 of the second linear motor 12 constitutes a motor stator for the linear motor 12. One ends of the shaft member 23 of the unit linear motors 15 are coupled together by an upper output shaft coupling frame 32, and other ends of the shaft member 23 of the unit linear motors 15 are coupled together by a lower output shaft coupling frame 33. An output shaft 34 of the linear motor 12 is provided in the center of the lower output shaft coupling frame 33.
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Where the press tool 6 has a plurality of individual tools 6a as shown in
With reference to
When a required press tonnage is smaller than a set press tonnage, the coupling state and motor-to-be-used selection control means 51 controllably brings the coupling switching mechanism 13 into a decoupling state to allow only the second linear motor 12 to be driven. When the required press tonnage is at least the set press tonnage, the coupling state and motor-to-be-used selection control means 51 controllably brings the coupling switching mechanism 13 into a coupling state to allow both the first linear motor 11 and the second linear motor 12 to be driven. In this case, for example, the first linear motor 11 is driven in synchronism with the second linear motor 12. The coupling state and motor-to-be-used selection control means 51 recognizes the required press tonnage on the basis of, for example, a value described in the machining program or obtains it by performing a predetermined arithmetic operation on a press tool to be used which is specified by the machining program.
The unit linear motor selection control means 52 controllably and selectively drives some of the plurality of unit linear motors 15 of one of the first linear motor 11 and the second linear motor 12. More specifically, the unit linear motor selection control means 52 controllably drives, for example, only three or two of the unit linear motors 15 of the first linear motor 11 which are arranged at equally distributed positions.
The operation of the above configuration will be described. For machining with a greater press tonnage, the coupling switching mechanism 13 is brought into a coupling state in which the combining shaft 38 is fitted into both combining holes 39, 40 to drive both the first linear motor 11 and the second linear motor 12. Thus, a high thrust produced by driving both the first linear motor 11 and the second linear motor 12 can be used to elevate and lower the ram 14 for press working. The press working may be performed by driving only the first linear motor 11 without applying any driving current to the second linear motor 12. The first linear motor 11 provides higher power than the second linear motor 12, enabling machining with a greater press tonnage.
For machining with a smaller press tonnage, the coupling switching mechanism 13 is brought into a decoupling state by removing the combining shaft 38 from the combining hole 40 to allow only the second linear motor 12 to be driven. This allows the press working to be performed only by the second linear motor 12, which provides lower power, and allows the ram 14 to elevate and lower at a high speed for the press working. In this case, the output shaft 30 of the first linear motor 11 is disconnected from the second linear motor 12. Accordingly, the movable portion of the first linear motor 11 does not contribute to offering resistance or inertia to the driving of the second linear motor 11. This enables efficient machining.
Alternatively, for machining with a smaller press tonnage, it is possible to drive only some of the unit linear motors 15 of the second linear motor 12. Where the second linear motor 12 has two unit linear motors 15 as shown in the illustrated example, both unit linear motors need to be driven. However, where the second linear motor 12 has at least four unit linear motors 15, energy consumption can be saved by selectively driving the unit linear motors 15. Also for the driving of the first linear motor 11, the press working may be preformed by driving only some of the unit linear motors 15.
The coupling state and decoupling state of the coupling switching mechanism 13 may be selectively switched for each machining operation for one workpiece W or for each lot, or during machining of each workpiece W.
The linear motor mounted press machine configured as described above uses the linear motors 11, 12 to move the press tool 6 forward and backward. Thus, the linear motor mounted press machine does not require any mechanism for converting rotations into rectilinear motion, as opposed to press machines using rotary motors. This provides a simplified structure with a reduced number of parts. Further, the linear motor mounted press machine has the first linear motor 11 and the second linear motor 12, and the coupling switching mechanism 13 that releasably couples these linear motors together. This enables the optimum thrust for the press tonnage to be generated, allowing the single linear motor mounted press machine to efficiently perform different machining operations including one requiring a greater press tonnage and one requiring a high speed and a smaller press tonnage.
Each of the first linear motor 11 and the second linear motor 12 is an assembly of the unit linear motors 15. This allows the power of the individual unit linear motors 15 to be collectively utilized to obtain high power. Further, the plurality of unit linear motors 15 are installed around the press working axis center P. This provides balanced rectilinear-propagation outputs even with the installation of the plurality of unit linear motors 15. The number of the unit linear motors 15 of the second linear motor 12 is smaller than that of the first linear motor 11. Consequently, machining only with the second linear motor 12 allows a thrust of a small press tonnage to be efficiently produced.
When the coupling state and motor-to-be-used selection control means 51 is provided to controllably couple and drive the linear motors 11, 12 in accordance with the required press tonnage, the linear motors 11, 12 can be appropriately driven to efficiently perform a machining operation requiring a greater press tonnage and a machining operation requiring a high speed and a smaller press tonnage. When the unit linear motor selection control means 52 is provided to selectively drive some of the unit linear motors 15 of one of the first linear motor 11 and the second linear motor 12, energy-efficient machining corresponding to the press tonnage can be performed driving only some of the unit linear motors 15.
When the arrangements of the unit linear motors 15 of the first linear motor 11 and the second linear motor 12 are thus concentric and form a double arrangement, the entire arrangement can be made more compact. In this case, the second linear motor 12 for a smaller press tonnage is located inside. This enables a spatially efficient arrangement corresponding to the size of each of the linear motors 11, 12. Therefore, an efficient, more compact arrangement can be achieved.
In the above description, the embodiments are applied to a punch press. However, the present invention is applicable to general press machines, for example, press brakes.
While the present invention has been described with respect to preferred embodiments thereof, it will be apparent to those skilled in the art that the disclosed invention may be modified in numerous ways and may assume many embodiments other than those specifically set out and described above. Accordingly, it is intended by the appended claims to cover all modifications of the present invention that fall within the true spirit and scope of the invention.
Number | Date | Country | Kind |
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2006-223781 | Aug 2006 | JP | national |