PRESS SYSTEM

Abstract

A press system capable of achieving improvement in production rate is provided. A controller has a slide driven upward and downward based on a prescribed press motion. A position of the slide where a workpiece can be transported without interfering with an upper die is defined as a feed-allowable height. A stand-by height is higher than the feed-allowable height and located at a highest position in the press motion. The controller also has the work transported while the slide is moving between the feed-allowable height and the stand-by height.

Description

TECHNICAL FIELD

The present invention relates to a press system.

BACKGROUND ART

For example, Japanese Patent Laying-Open No. 2013-184222 (PTL 1) discloses a method of setting a rotary motion at the time when a crankshaft is rotated by a servo motor in a conventional press.

CITATION LIST

Patent Literature

PTL 1: Japanese Patent Laying-Open No. 2013-184222

SUMMARY OF INVENTION

Technical Problem

In a conventional servo press, an operation of a slide in a pendular motion and an operation of a feeder are alternately performed. The servo press has been demanded to achieve a further improved production rate.

An object of the present invention is to provide a press system capable of achieving an improved production rate.

Solution to Problem

In a conventional servo press, an approach to improvement in production rate in a pendular motion by minimizing a distance of travel of a slide by setting a lower limit position where a workpiece can be transported without interfering with a die as a slide stop position has been adopted. The present inventors have found during studies about further improvement in production rate of the servo press that improvement in production rate can be achieved by increasing a distance of travel of the slide by shifting the slide stop position upward, and made the present invention as below.

A press system according to the present invention includes a press portion, a transportation portion, and a controller. The press portion includes an electric motor, an eccentric mechanism, a slide, and a bolster. The eccentric mechanism converts a rotary motion by the electric motor into an upward and downward motion. An upper die can be attached to the slide and the slide is driven upward and downward with the eccentric mechanism being interposed. A lower die can be attached to the bolster. The press portion is configured to press work a workpiece by upward and downward movement of the slide with respect to the bolster. The transportation portion is configured to transport the workpiece. The controller is configured to control the press portion and the transportation portion. The controller is configured to have the slide driven upward and downward based on a prescribed press motion. A position of the slide where the workpiece can be transported without interfering with the upper die is defined as a feed-allowable height, and a position higher than the feed-allowable height and highest in the press motion is defined as a stand-by height. The controller is also configured to have the workpiece transported while the slide is moving between the feed-allowable height and the stand-by height.

Advantageous Effects of Invention

According to the press system in the present invention, a production rate can be improved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a construction of a press system based on an embodiment.

FIG. 2 is a perspective view of a press apparatus based on the embodiment.

FIG. 3 is a lateral cross-sectional view showing a main portion of the press apparatus.

FIG. 4 is a plan view of a partial cross-section showing another main portion of the press apparatus.

FIG. 5 is a diagram illustrating overview of a drive system of the press system based on the embodiment.

FIG. 6 is a functional block diagram of a CPU based on the embodiment.

FIG. 7 is a schematic diagram showing arrangement of a die and a workpiece when a slide is located at a feed-allowable height.

FIG. 8 is a schematic diagram showing arrangement of the die and the workpiece when the slide is located at a touch position.

FIG. 9 is a schematic diagram showing arrangement of the die and the workpiece when the slide is located at a work end position.

FIG. 10 is a first diagram illustrating an angle of rotation of a main shaft corresponding to each position representing a slide position parameter.

FIG. 11 is a second diagram illustrating an angle of rotation of the main shaft corresponding to each position representing a slide position parameter.

FIG. 12 is a flowchart illustrating generation of a motion in the press system based on the embodiment.

FIG. 13 is a diagram showing a press motion and a feeder motion generated by the press system based on the embodiment.

FIG. 14 is a diagram showing an approach to setting of a monitoring position.

DESCRIPTION OF EMBODIMENTS

The present embodiment will be described in detail with reference to the drawings. The same or corresponding elements in the drawings have the same reference characters allotted and description thereof will not be repeated.

The present example relates to a press apparatus and describes a forward feed press apparatus by way of example.

<Overall Construction>

FIG. 1 is a diagram illustrating a construction of a press system based on an embodiment. As shown in FIG. 1, the press system includes an uncoiler 100, a leveler feeder (a transportation portion) 200, a press apparatus (a press portion) 10, and a conveyor 120.

A coil material (a strip plate) is wound around uncoiler 100. In the present embodiment, press working of the coil material as a workpiece (material) will be described. The coil material unwound from uncoiler 100 is transported to press apparatus 10 by leveler feeder 200.

Leveler feeder 200 adjusts a position of a feed height of the coil material transported from uncoiler 100 to press apparatus 10 and transports the coil material to press apparatus 10 under an operation condition (a feeder motion) in a set direction of transportation.

Press apparatus 10 press works the coil material transported from leveler feeder 200.

Conveyor 120 transports the workpiece formed by press working by press apparatus 10. Conveyor 120 can also transport the formed workpiece, for example, to a next press apparatus.

Components in the press system are in synchronization with one another, and a series of operations is sequentially and successively performed. The coil material is transported from uncoiler 100 via leveler feeder 200 to press apparatus 10. Then, press apparatus 10 performs press working, and the worked workpiece is transported by conveyor 120. A series of processes above is repeated.

The above construction of the press system is by way of example and limitation thereto is not particularly intended.

Leveler feeder 200 is operated in accordance with an instruction from press apparatus 10. In this connection, a controller configured to control leveler feeder 200 is provided in press apparatus 10.

Though the present example describes a construction in which the controller configured to control leveler feeder 200 is provided in press apparatus 10, limitation thereto is not intended, and for example, a controller configured to control press apparatus 10 may be provided on a side of leveler feeder 200. A controller configured to control press apparatus 10 and leveler feeder 200 may be arranged at a position different from press apparatus 10 and leveler feeder 200 to remotely control press apparatus 10 and leveler feeder 200. The embodiment describes an example in which a single controller controls both of leveler feeder 200 and press apparatus 10.

<Press Apparatus>

FIG. 2 is a perspective view of press apparatus 10 based on the embodiment.

FIG. 2 shows a forward feed press apparatus without a plunger by way of example.

Press apparatus 10 includes a main body frame 2, a slide 20, a bed 4, a bolster 5, a control panel 6, and a controller 40.

Slide 20 is supported in a substantially central portion of main body frame 2 of press apparatus 10 as being vertically movable. Bolster 5 attached onto bed 4 is arranged under slide 20. Controller 40 is provided laterally to main body frame 2. Control panel 6 connected to controller 40 is provided laterally to main body frame 2 and in front of controller 40.

An upper die of dice for working a workpiece is removably attached to a lower surface of slide 20. A lower die of the dice for working a workpiece is removably attached to an upper surface of bolster 5. A prescribed workpiece corresponding to the dice is placed on the lower die, the upper die is lowered together with slide 20, and the workpiece is press worked as being sandwiched between the upper die and the lower die.

A remote controller (remote control unit) 70 provided to communicate with a main body of press apparatus 10 and to allow external remote control is provided. An operator (a person responsible for operation) can perform various setting operations by operating remote controller 70. Remote controller 70 can communicate with controller 40 to operate press apparatus 10 in accordance with an instruction therefrom.

The present example shows that remote controller 70 is provided with an up button 72 and a down button 74 for vertically operating slide 20 and an enter button 76.

Control panel 6 is provided to input various types of data necessary for controlling press apparatus 10, and includes a switch and a numeric keypad for inputting data and a display configured to show a setting screen and data output from press apparatus 10.

Such a programmable display that a transparent touch switch panel is attached to a front surface of a graphic display such as a liquid crystal display or a plasma display is adopted as a display.

Control panel 6 may include a data input device which receives input of data from an external storage medium such as an integrated circuit (IC) card where data set in advance is stored or a communication device which transmits and receives data wirelessly or through a communication line.

Though the present example describes a construction in which both of control panel 6 and remote controller 70 are provided for press apparatus 10, the construction of press apparatus 10 is by way of example and limitation thereto is not intended. For example, only one of control panel 6 and remote controller 70 may be provided for press apparatus 10.

FIG. 3 is a lateral cross-sectional view showing a main portion of press apparatus 10. As shown in FIG. 3, press apparatus 10 is implemented by a servo press.

Press apparatus 10 includes a servo motor 121, a spherical hole 33A, a screw shaft 37, a spherical portion 37A, a thread portion 37B, and a connecting rod main body 38. Press apparatus 10 further includes a female thread portion 38A, a connecting rod 39, a main shaft 110, an eccentric portion 110A, a side frame 111, bearing portions 112 to 114, a main gear 115, a power transmission shaft 116, a transmission gear 116A, bearing portions 117 and 118, and a pulley 119.

In press apparatus 10, servo motor 121 drives slide 20. Servo motor 121 represents one example of an electric motor. In spherical hole 33A provided in an upper portion of slide 20, spherical portion 37A provided at a lower end of screw shaft 37 for adjusting a die height is rotatably inserted so as not to come off. Spherical hole 33A and spherical portion 37A make up a spherical joint. Thread portion 37B of screw shaft 37 is exposed upward through slide 20, and screwed to female thread portion 38A of connecting rod main body 38 provided above screw shaft 37. Screw shaft 37 and connecting rod main body 38 make up extendable connecting rod 39.

The die height refers to a distance from a lower surface of slide 20 at the time when slide 20 is arranged at a bottom dead center to an upper surface of bolster 5.

An upper portion of connecting rod 39 is rotatably coupled to eccentric portion 110A like a crank provided in main shaft 110. Main shaft 110 is movably supported by bearing portions 112, 113, and 114 located at three front and rear locations between a pair of left and right thick side frames 111 which form main body frame 2. Main gear 115 is attached to a rear portion of main shaft 110.

Main gear 115 is meshed with transmission gear 116A of power transmission shaft 116 provided below. Power transmission shaft 116 is movably supported by bearing portions 117 and 118 located at two front and rear locations between side frames 111. Power transmission shaft 116 has a rear end attached to driven pulley 119. Pulley 119 is driven by servo motor 121 arranged below.

Press apparatus 10 further includes a bracket 122, an output shaft 121A, a pulley 123, a belt 124, a bracket 125, a position detector 126, a rod 127, a position sensor 128, an auxiliary frame 129, and bolts 131 and 132.

Servo motor 121 is supported between side frames 111 with bracket 122 substantially in an L shape being interposed. Servo motor 121 has output shaft 121A projecting along a front-rear direction of press apparatus 10, and motive power is transmitted by belt 124 wound around driving pulley 123 provided on output shaft 121A and driven pulley 119.

A pair of brackets 125 projecting rearward between side frames 111 from two upper and lower locations is attached on a rear surface side of slide 20. Rod 127 which implements position detector 126 such as a linear scale is attached between upper and lower brackets 125. Rod 127 is provided with a scale for detecting a vertical position of slide 20 and vertically movably fitted into position sensor 128 similarly implementing position detector 126. Position sensor 128 is fixed to auxiliary frame 129 provided in one side frame 111.

Auxiliary frame 129 is formed in a vertically elongated manner. The auxiliary frame has a lower portion attached to side frame 111 by bolt 131 and an upper portion vertically slidably supported by bolt 132 inserted in a vertically elongated hole. Auxiliary frame 129 has thus only any one side (a lower side in the present embodiment) of upper and lower sides fixed to side frame 111 and has the other side vertically movably supported. Therefore, the auxiliary frame is not affected by contraction and extension caused by variation in temperature of side frame 111. Position sensor 128 can thus accurately detect a slide position and a die height position without being affected by such contraction and extension of side frame 111.

A slide position of slide 20 and a die height are adjusted by a slide position adjustment mechanism 133 (FIG. 4) provided in slide 20. FIG. 4 is a plan view of a partial cross-section showing another main portion of press apparatus 10.

As shown in FIG. 4, slide position adjustment mechanism 133 is constituted of a worm wheel 134 attached to an outer circumference of spherical portion 37A with a pin 37C being interposed, a worm gear 135 meshed with worm wheel 134, an input gear 136 attached to an end of worm gear 135, and an induction motor 138 including an output gear 137 (FIG. 3) meshed with input gear 136. Induction motor 138 is in a flat shape shorter in axial length and constructed to be compact. Screw shaft 37 can be turned by a rotary motion of induction motor 138 with worm wheel 134 being interposed. A length of screwing between thread portion 37B of screw shaft 37 and female thread portion 38A of connecting rod main body 38 is thus varied to adjust the slide position of slide 20 and the die height.

<Configuration of Drive System of Press System>

FIG. 5 is a diagram illustrating overview of a drive system of the press system based on the embodiment.

As shown in FIG. 5, leveler feeder 200 includes a transportation roller 63, a servo motor 62, an encoder 64, a feed completion detector 68, and a servo amplifier 60.

Press apparatus 10 includes controller 40, a servo amplifier 66, servo motor 121, an encoder 65, main gear 115, main shaft 110, eccentric portion 110A, slide 20, an upper die 22A, a lower die 22B, and bolster 5.

Controller 40 includes a central processing unit (CPU) 42, a memory 44, a communication circuit 46, and an input unit 48.

Communication circuit 46 is provided to be able to communicate with remote controller 70.

CPU 42 outputs a target value to servo amplifier 60. Servo amplifier 60 gives a speed instruction to servo motor 62 based on the target value. Transportation roller 63 performs an operation to transport a workpiece W as servo motor 62 is driven. Feed completion detector 68 determines whether or not an operation to transport workpiece W has been completed. When the feed completion detector detects completion of the transportation operation and stop of workpiece W, the feed completion detector outputs a result of detection to CPU 42 as a feed completion signal.

Encoder 64 outputs a feedback signal based on the number of rotations of servo motor 62 in accordance with the speed instruction to servo amplifier 60.

Servo amplifier 60 adjusts the number of rotations of servo motor 62 to a value in accordance with the target value by controlling supply of electric power to servo motor 62 based on the feedback signal from encoder 64.

Through the processing, CPU 42 controls a speed of transportation in the operation to transport workpiece W.

Similarly, CPU 42 outputs a target value to servo amplifier 66. Servo amplifier 66 gives a speed instruction to servo motor 121 based on the target value. Main gear 115 drives main shaft 110 as servo motor 121 is driven. As main shaft 110 is driven, eccentric portion 110A is rotated. Eccentric portion 110A is coupled to slide 20, and slide 20 to which upper die 22A is attached moves upward and downward in accordance with a rotation of eccentric portion 110A. Eccentric portion 110A implements an eccentric mechanism which converts a rotary motion by servo motor 121 into an upward and downward motion of slide 20. As slide 20 is driven upward and downward and lowered to a position of the bottom dead center under an operation condition (press motion) in the set upward and downward direction, press working of workpiece W transported to a position between upper die 22A and lower die 22B is performed.

Upper die 22A is a movable die which is attached to slide 20 and is reciprocatively vertically moved integrally with slide 20 with upward and downward movement of slide 20. Lower die 22B is a fixed die attached to bolster 5 and placed and fixed onto bolster 5. As slide 20 moves upward and downward with respect to bolster 5, workpiece W is sandwiched between upper die 22A and lower die 22B and press worked.

Encoder 65 outputs a feedback signal based on the number of rotations of servo motor 121 in accordance with a speed instruction to servo amplifier 66.

Servo amplifier 66 adjusts the number of rotations of servo motor 121 to a value in accordance with the target value by controlling supply of electric power to servo motor 121 based on the feedback signal from encoder 65.

Through the processing, CPU 42 controls a speed of slide 20 in the upward and downward movement.

CPU 42 based on the embodiment performs processing for synchronizing a transportation operation by leveler feeder 200 (which is also simply referred to as a feeder) with the upward and downward movement of slide 20 of press apparatus 10 based on control data stored in memory 44.

Specifically, memory 44 stores control data in which upward and downward movement of slide 20 is associated with a workpiece transportation operation by leveler feeder 200.

Input unit 48 accepts input of various parameters. In the present example, input unit 48 accepts input of a parameter through control panel 6 or remote controller 70. An operator inputs various parameters by operating a switch and a numeric keypad in control panel 6 or each button on remote controller 70. Control panel 6 and remote controller 70 implement the operation portion in the embodiment.

A parameter received by input unit 48 includes a slide position parameter relating to a position of slide 20 in the upward and downward direction with respect to bolster 5. A parameter received by input unit 48 includes a transportation parameter relating to an operation by leveler feeder 200.

<Generation of Motion>

A method of generating a motion based on the embodiment will now be described.

FIG. 6 is a functional block diagram of CPU 42 based on the embodiment.

As shown in FIG. 6, CPU 42 includes a touch speed generator 51, a press motion generator 53, a feeder motion generator 55, a motion synthesizer 56, and an execution unit 58.

Each one in the functional block diagram is implemented in coordination with each component (such as communication circuit 46) by execution by CPU 42 of a prescribed application program stored in memory 44.

Touch speed generator 51 sets a speed (touch speed) of slide 20 at the time when slide 20 is lowered and upper die 22A comes in contact with workpiece W based on a material property and a thickness of workpiece W input to input unit 48.

Press motion generator 53 automatically generates a press motion based on a slide position parameter input to input unit 48. The slide position parameter includes a feed-allowable height, a touch position, and a work end position.

Feeder motion generator 55 automatically generates a feeder motion based on a transportation parameter input to input unit 48. The transportation parameter includes a feed length.

Motion synthesizer 56 automatically generates a synthesized motion by automatically synthesizing the press motion generated by press motion generator 53 and a feeder motion generated by feeder motion generator 55.

The feed-allowable height refers to a lower limit of a position of slide 20 where upper die 22A does not interfere with transported workpiece W. FIG. 7 is a schematic diagram showing arrangement of the die and workpiece W when slide 20 is located at the feed-allowable height. When slide 20 is distant from bolster 5 by a distance greater than the feed-allowable height, workpiece W can be transported without interfering with upper die 22A.

The touch position refers to a position of slide 20 at the time when upper die 22A comes in contact with workpiece W. FIG. 8 is a schematic diagram showing arrangement of the die and workpiece W when slide 20 is located at the touch position. When slide 20 lowered toward bolster 5 reaches the touch position, upper die 22A comes in contact with workpiece W placed on lower die 22B.

The work end position refers to a position of slide 20 at the time point of end of press working of workpiece W. FIG. 9 is a schematic diagram showing arrangement of the die and workpiece W when slide 20 is located at the work end position. When slide 20 lowered toward bolster 5 reaches the work end position, press working of workpiece W ends.

The feed length refers to a length of transportation of workpiece W by leveler feeder 200 in the direction of transportation of workpiece W after end of press working of workpiece W and before start of next press working. A speed of transportation of workpiece W transported by leveler feeder 200 is referred to as a feed rate. The feed rate is saved in memory 44. Alternatively, the feed rate may be included in a transportation parameter input to input unit 48.

When press motion generator 53 generates a press motion, an operation mode for maximizing an amount of production per unit time is set. Furthermore, a production rate (unit: shot per minute (SPM)) is set.

The operation mode includes a rotary motion, a reverse motion, and a pendular motion.

The rotary motion refers to an operation mode in which eccentric portion 110A (FIG. 3) is rotated in one direction to drive slide 20 in one cycle.

The reverse motion refers to an operation mode in which slide 20 is reversely driven between a down stroke and an up stroke between two angles of rotation corresponding to prescribed lower limit position and upper limit position set between angles of rotation of eccentric portion 110A corresponding to the top dead center and the bottom dead center of slide 20.

The pendular motion refers to an operation mode in which slide 20 is reciprocatively driven across the bottom dead center by setting as two upper limit positions, two angles of rotation distant by a prescribed angle in a direction of forward rotation and a direction of reverse rotation from a bottom dead center angle of rotation of eccentric portion 110A corresponding to the bottom dead center of slide 20 and rotationally driving the slide in one direction from one upper limit position across the bottom dead center angle of rotation to the other upper limit position.

Execution unit 58 controls a transportation operation by leveler feeder 200 and press working by press apparatus 10 based on a synthesized motion generated by motion synthesizer 56. Specifically, execution unit 58 outputs a target value for driving servo motors 62 and 121 to servo amplifiers 60 and 66 based on the synthesized motion, and performs synchronization processing for synchronizing the press motion and the feeder motion with each other.

FIG. 10 is a first diagram illustrating an angle of rotation of main shaft 110 corresponding to each position representing a slide position parameter. FIG. 10 shows angles of rotation of main shaft 110 corresponding to a top dead center TDC, a bottom dead center BDC, a stand-by height P0, a monitoring position Pa, a feed-allowable height P1, a touch position P2, a work end position P3, a jump prevention height P4, a feed-allowable height P5, and a stand-by height P6 of slide 20. FIG. 10 shows each position representing a slide position parameter when main shaft 110 is rotated clockwise in the figure.

The operation mode of slide 20 is set to the pendular motion in which the slide is reciprocatively driven across bottom dead center BDC with stand-by heights P0 and P6 being defined as upper limit positions. Slide 20 starts lowering from stand-by height P0, sequentially passes monitoring position Pa, feed-allowable height P1, touch position P2, and work end position P3, reaches bottom dead center BDC, moves upward from bottom dead center BDC, sequentially passes jump prevention height P4 and feed-allowable height P5, moves to stand-by height P6, and stops. Since stand-by heights P0 and P6 are located at positions lower than top dead center TDC, slide 20 never passes top dead center TDC.

As shown in FIG. 10, stand-by height P0 is located at a position higher than feed-allowable height P1. Stand-by height P6 is located at a position higher than feed-allowable height P5. Stand-by heights P0 and P6 are located at a highest position in a press motion. Monitoring position Pa is set at a position higher than feed-allowable height P1 and lower than stand-by height P0 in the upward and downward direction of slide 20.

Work end position P3 is set as a position higher than bottom dead center BDC. Lowered slide 20 passes work end position P3 before reaching bottom dead center BDC.

Jump prevention height P4 is set as a position higher than bottom dead center BDC. Slide 20 starts moving upward after it passes bottom dead center BDC, and passes jump prevention height P4. In order to prevent wobble of workpiece W between upper die 22A and lower die 22B at the time when upper die 22A is raised after end of press working of workpiece W, a speed of slide 20 while it is moved from work end position P3 to jump prevention height P4 is set to be low.

A different position of jump prevention height P4 can be set for each condition of a material property, a thickness, and a method of working of workpiece W. Set jump prevention height P4 is saved in memory 44 (FIG. 5). When jump prevention height P4 corresponding to workpiece W to be press worked has not been saved in memory 44 at the time of change in material property, thickness, or method of working of workpiece W, jump prevention height P4 is set by making trials a plurality of times before starting working.

FIG. 11 is a second diagram illustrating an angle of rotation of main shaft 110 corresponding to each position representing a slide position parameter. FIG. 11 shows angles of rotation of main shaft 110 corresponding to top dead center TDC, bottom dead center BDC, stand-by height P0, monitoring position Pa, feed-allowable height P1, touch position P2, work end position P3, jump prevention height P4, feed-allowable height P5, and stand-by height P6 of slide 20 as in FIG. 10. FIG. 11 shows each position representing a slide position parameter when main shaft 110 is rotated counterclockwise in the figure.

Stand-by height P0 shown in FIG. 11 is a position the same as stand-by height P6 which represents a stop position of slide 20 shown in FIG. 10. Monitoring position Pa, feed-allowable height P1, touch position P2, work end position P3, jump prevention height P4, and feed-allowable height P5 shown in FIGS. 10 and 11 are set in line symmetry with respect to a straight line which passes through top dead center TDC and bottom dead center BDC in FIGS. 10 and 11. Stand-by height P6 shown in FIG. 11 is a position the same as stand-by height P0 which represents a movement start position of slide 20 shown in FIG. 10. Slide 20 starts lowering from stand-by height P0, sequentially passes monitoring position Pa, feed-allowable height P1, touch position P2, and work end position P3, reaches bottom dead center BDC, starts moving upward from bottom dead center BDC, sequentially passes jump prevention height P4 and feed-allowable height P5, moves to stand-by height P6, and stops.

FIG. 12 is a flowchart illustrating generation of a motion in the press system based on the embodiment.

As shown in FIG. 12, initially, in step S1, various parameters are input to input unit 48. Specifically, an operator inputs parameters necessary for generating a motion by operating control panel 6 or remote controller 70 (FIG. 2).

Then, in step S2, a touch speed is set. Specifically, touch speed generator 51 sets a touch speed by referring to a touch speed table for each material property of workpiece W stored in memory 44 (FIG. 5) of controller 40, based on input material property and thickness of workpiece W.

Then, in step S3, a feeder motion is generated. Specifically, feeder motion generator 55 generates a feeder motion based on input feed length and feed rate.

FIG. 13 is a diagram showing a press motion and a feeder motion generated by the press system based on the embodiment. The abscissa in the graph in FIG. 13 (A) represents time and the ordinate represents an angular speed ω of main shaft 110 based on rotational drive by servo motor 121. An angular speed (max represents a value set as a maximum value of the angular speed of main shaft 110. An angular speed ω1 represents an angular speed of main shaft 110 corresponding to a touch speed set in step S2. As main shaft 110 rotates at angular speed ω1, a lowering speed of slide 20 is set to a touch speed. In FIG. 13 (A), stand-by height P0, monitoring position Pa, feed-allowable height P1, touch position P2, work end position P3, jump prevention height P4, feed-allowable height P5, and stand-by height P6 are plotted. The abscissa in the graph in FIG. 13 (B) represents time and the ordinate represents a speed of transportation v of workpiece W.

As shown in FIG. 13 (B), the transportation speed is increased up to the set feed rate at a prescribed acceleration from a state that workpiece W remains stopped (speed of transportation v=0). After reaching the feed rate, transportation of workpiece W at the set feed rate is continued to a position where the speed can be lowered by deceleration at a prescribed acceleration to speed of transportation v=0 at the time point of transportation of workpiece W by a set transportation length. A prescribed value of an acceleration at the time of increase or decrease in transportation speed is saved in memory 44.

Workpiece W is decelerated from the set feed rate at a prescribed acceleration. Speed of transportation v=0 is achieved at the time point of transportation of workpiece W by the set transportation length. Transportation of workpiece W is thus completed. The feeder motion is generated as set forth above.

Referring back to FIG. 12, in step S4, a press motion is generated. Specifically, press motion generator 53 generates a press motion based on the input feed-allowable height (P1), touch position (P2), and work end position (P3) and the touch speed set in step S2.

As shown in FIG. 13 (A), stand-by height P0 refers to a position where slide 20 remains stopped, and hence angular speed ω of main shaft 110 at stand-by height P0 is zero. Stand-by height P0 is set as a position from which the main shaft can be accelerated to maximum angular speed ωmax at an angle of rotation corresponding to feed-allowable height P1 by being accelerated at a prescribed acceleration.

Slide 20 starts lowering from stand-by height P0 toward bottom dead center BDC, and is accelerated at a prescribed acceleration until main shaft 110 reaches maximum angular speed ωmax. Main shaft 110 reaches its maximum angular speed ωmax when slide 20 passes feed-allowable height P1. Slide 20 passes feed-allowable height P1 at the maximum speed. Main shaft 110 completes acceleration before slide 20 passes feed-allowable height P1 as slide 20 is lowered.

After maximum angular speed ωmax is reached, rotation of main shaft 110 at maximum angular speed ωmax is continued to a position where the speed can be lowered by deceleration at a prescribed acceleration to touch speed ω1 at an angle of rotation corresponding to touch position P2. Prescribed values of maximum angular speed (max of main shaft 110 and an acceleration at the time of acceleration and deceleration are saved in memory 44.

Main shaft 110 is decelerated from maximum angular speed ωmax and rotated at angular speed ω1 at the time point when slide 20 reaches touch position P2. Thereafter, main shaft 110 is rotated at equal angular speed ω1 until slide 20 reaches work end position P3. Slide 20 is thus lowered at the touch speed from touch position P2 to work end position P3.

When slide 20 reaches work end position P3, main shaft 110 (and slide 20) starts acceleration. While slide 20 is moving between work end position P3 and jump prevention height P4, in order to prevent wobble of workpiece W, slide 20 is moved at a speed slightly higher than the touch speed and main shaft 110 is rotated at a speed slightly higher than angular speed ω1.

When slide 20 reaches jump prevention height P4, main shaft 110 is again accelerated at a prescribed acceleration until maximum angular speed ωmax is reached. After maximum speed ωmax is reached, rotation of main shaft 110 at maximum angular speed ωmax is continued until slide 20 reaches feed-allowable height P5. Slide 20 passes feed-allowable height P5 at the maximum speed.

As slide 20 passes feed-allowable height P5, main shaft 110 is decelerated at a prescribed acceleration from maximum angular speed ωmax. Main shaft 110 starts deceleration after it passes feed-allowable height P5 as slide 20 is moved upward. Main shaft 110 stops rotation at the time point when slide 20 reaches stand-by height P6. Slide 20 stops at a position at stand-by height P6. Stand-by height P6 is set as a position where the main shaft is decelerated to a zero angular speed by deceleration at a prescribed acceleration from an angle of rotation corresponding to feed-allowable height P5. The press motion is generated as set forth above.

Then, in step S5, a synthesized motion is generated. Specifically, motion synthesizer 56 generates a synthesized motion by synthesizing the feeder motion generated in step S3 and the press motion generated in step S4.

As shown in FIG. 13, after slide 20 passes feed-allowable height P5 at the highest speed, transportation of workpiece W is started. At the time point when slide 20 passes feed-allowable height P5, speed of transportation v of workpiece W is v=0. At the time point of start of transportation of workpiece W, slide 20 is moving from feed-allowable height P5 to stand-by height P6. While slide 20 is being transported between feed-allowable height P5 and stand-by height P6, workpiece W is also being transported. While slide 20 is decelerated, transportation of workpiece W by leveler feeder 200 is started.

Slide 20 which has stopped at stand-by height P6 starts lowering after lapse of a prescribed time period. Main shaft 110 which has stopped rotation when slide 20 reached stand-by height P6 starts rotation in a reverse direction after lapse of the prescribed time period.

A time period elapsed since start of transportation of workpiece Was usual until completion of feed in transportation of workpiece W by a feed length at a prescribed acceleration and at a set feed rate is referred to as a feeder movement time period. Main shaft 110 starts rotation such that slide 20 reaches monitoring position Pa after lapse of a press waiting time (margin) ts since a time point of lapse of the feeder movement time period. Leveler feeder 200 stops its operation while slide 20 is accelerated. Feed of workpiece W has been completed press waiting time (margin) ts before the time point when slide 20 lowered from stand-by height P0 reaches monitoring position Pa higher than feed-allowable height P1. Feed of workpiece W has been completed by the time point when slide 20 reaches feed-allowable height P1.

The synthesized motion in which interference between an operation to transport workpiece W and upward and downward movement of upper die 22A does not occur is thus generated.

An approach to setting of monitoring position Pa will be described. FIG. 14 is a diagram showing an approach to setting of monitoring position Pa. The abscissa in the graph in FIGS. 14 (A) and (B) represents time. The ordinate in the graph in FIG. 14 (A) represents a position P of slide 20. The ordinate in the graph in FIG. 14 (B) represents angular speed co of main shaft 110 based on rotational drive by servo motor 121.

A solid line in FIG. 14 (A) represents a position of slide 20 when the slide is lowered as being accelerated at a prescribed acceleration until time Ta and forced stop of slide 20 is started at time Ta, and a solid line in FIG. 14 (B) represents an angular speed of main shaft 110 when the main shaft is rotated as being accelerated at a prescribed angular acceleration until time Ta and forced stop of rotation of main shaft 110 is started at time Ta. A dashed line in FIG. 14 (A) represents a position of slide 20 after time Ta when slide 20 is lowered in a normal operation, and a dashed line in FIG. 14 (B) represents an angular speed of main shaft 110 after time Ta when main shaft 110 is rotated in a normal operation.

As described above, stand-by height P0 refers to a position where slide 20 remains stopped, and hence angular speed co of main shaft 110 at stand-by height P0 is zero. Main shaft 110 is accelerated at a prescribed acceleration so as to reach maximum angular speed co at the time when slide 20 passes feed-allowable height P1. At time Ta, as shown in FIG. 14 (A), slide 20 reaches monitoring position Pa.

At the time point of time Ta when slide 20 is lowered from stand-by height P0 and reaches monitoring position Pa, controller 40 determines whether or not completion of feed of workpiece W has been detected. Controller 40 determines whether or not it has received input of a feed completion signal indicating completion of transportation of workpiece W from feed completion detector 68 (FIG. 5) at time Ta a prescribed time period after start of lowering of slide 20 from stand-by height P0.

When completion of feed of workpiece W has not been detected at time Ta, controller 40 forces slide 20 to stop. As shown in FIG. 14 (B), main shaft 110 is decelerated at a prescribed acceleration after time Ta. At time Tb, main shaft 110 stops rotation, angular speed ω shown in FIG. 14 (B) is set to zero, and slide 20 stops. A stop position Pb where slide 20 stops is higher than feed-allowable height P1 as shown in FIG. 14 (A).

Monitoring position Pa is thus set such that slide 20 which has started lowering from stand-by height P0 and reached monitoring position Pa can start deceleration at monitoring position Pa and stop at stop position Pb higher than feed-allowable height P1 when completion of feed of workpiece W has not been detected.

Referring back to FIG. 12, in step S6, workpiece W is worked in accordance with the generated synthesized motion. Execution unit 58 has press working of workpiece W performed based on the generated synthesized motion.

Then, in step S7, whether or not a result of working of workpiece W based on the synthesized motion generated in step S5 is appropriate is determined. For example, torque required for rotation of main shaft 110 is calculated based on a current value of servo motor 121, and when the torque exceeds an allowable value, the result of working is determined as inappropriate. Alternatively, for example, vibration generated during working is determined, and when vibration exceeds an allowable value, the result of working is determined as inappropriate. The allowable value of torque or vibration has been saved in memory 44.

When the result of working is determined as inappropriate (NO in step S7), the synthesized motion is modified in step S8. For example, a speed other than the speed during press working (that is, the touch speed of slide 20 (angular speed ω1 of main shaft 110)) is modified to be lower.

After the synthesized motion is modified, the process returns to step S6, where workpiece W is worked in accordance with the modified synthesized motion. In succession, in step S7, whether or not the result of working of workpiece W based on the modified synthesized motion is appropriate is determined.

When the result of working is determined as appropriate (YES in step S7), the process proceeds to step S9, where the synthesized motion is saved in memory 44.

In step S10, the result is output. Values input as a slide position parameter and a transportation parameter and a set and calculated value determined with automatic generation of a motion are shown on the display of control panel 6, so that an operator can readily know a state of operation by the press system by viewing that screen on the display.

Then, the process ends (end).

<Function and Effect>

A function and effect of the present embodiment will now be described.

According to the press system based on the embodiment, as shown in FIGS. 10 and 11, stand-by height P0 located at a position higher than feed-allowable height P1 is set and stand-by height P6 located at a position higher than feed-allowable height P5 is set. As shown in FIG. 13, transportation of workpiece W is started while slide 20 is moving between feed-allowable height P5 and stand-by height P6, and transportation thereof is completed while slide 20 is moving between stand-by height P0 and feed-allowable height P1. Transportation of workpiece W and movement of slide 20 overlap in time.

When slide 20 is stopped at feed-allowable height P1, P5, the speed of slide 20 should be zero at feed-allowable height P1, P5. By setting a position where slide 20 is to be stopped at stand-by height P0, P6 higher than feed-allowable height P1, P5 instead of feed-allowable height P1, P5, slide 20 is moved at a speed higher than zero at the time point of passage by feed-allowable height P1, P5. Thus, a time period required for slide 20 to lower from feed-allowable height P1 and a time period until slide 20 is moved upward and reaches feed-allowable height P5 can be shortened. More specifically, a time period for slide 20 to be moved from feed-allowable height P1 across bottom dead center BDC to feed-allowable height P5 can be shortened.

Before slide 20 passes feed-allowable height P1 and after slide 20 passes feed-allowable height P5, workpiece W can be transported without interfering with a die. Since the time period for slide 20 to be moved from bottom dead center BDC to feed-allowable height P5 is shortened, timing of start of transportation of workpiece W can be advanced. As the time period required for one cycle of press working is shortened, a production rate of the press system can be improved.

As shown in FIG. 13, main shaft 110 has been decelerated from maximum angular speed ωmax to zero by the time when slide 20 reaches stand-by height P6 after it passed feed-allowable height P5. Therefore, servo motor 121 has also been decelerated by the time when slide 20 reaches stand-by height P6 after it passed feed-allowable height P5. Transportation of workpiece W by leveler feeder 200 is started during deceleration of servo motor 121.

By doing so, a time period of transportation of workpiece W and a time period of movement of slide 20 can reliably overlap with each other. From a point of view of a shorter distance of travel of slide 20, stand-by height P6 is desirably set at a position closer to feed-allowable height P5. By making such setting that servo motor 121 has already been decelerated by the time point of start of transportation of workpiece W, slide 20 can readily be stopped at stand-by height P6 closer to feed-allowable height P5.

As shown in FIG. 13, deceleration of main shaft 110 is started after slide 20 passes feed-allowable height P5. Therefore, while slide 20 is moving upward, deceleration of servo motor 121 is started after slide 20 passes feed-allowable height P5. Servo motor 121 has not yet been decelerated at the time of passage by feed-allowable height P5. Slide 20 passes feed-allowable height P5 at the highest speed. By doing so, a time period for slide 20 to be moved from feed-allowable height P1 across bottom dead center BDC to feed-allowable height P5 can reliably be shortened.

As shown in FIG. 13, main shaft 110 has been accelerated from a zero angular speed to maximum angular speed (max by the time when slide 20 reaches feed-allowable height P1 after it starts movement from stand-by height P0. Therefore, servo motor 121 has also been accelerated while slide 20 is moving from stand-by height P0 to feed-allowable height P1. Transportation of workpiece W by leveler feeder 200 is completed during acceleration of servo motor 121.

By doing so, a time period of transportation of workpiece W and a time period of movement of slide 20 can reliably overlap with each other. From a point of view of a shorter distance of travel of slide 20, stand-by height P0 is desirably set at a position closer to feed-allowable height P1. By making such setting that servo motor 121 is being accelerated and the slide is moved at a speed lower than the highest speed at the time point of completion of feed of workpiece W, slide 20 can readily be lowered from stand-by height P0 closer to feed-allowable height P1.

As shown in FIG. 13, main shaft 110 has completed acceleration before slide 20 passes feed-allowable height P1. Therefore, as slide 20 is lowered, acceleration of servo motor 121 has been completed before slide 20 passes feed-allowable height P1. By the time point of passage by feed-allowable height P1, servo motor 121 has reached the highest speed. Slide 20 passes feed-allowable height P1 at the highest speed. By doing so, a time period for slide 20 to be moved from feed-allowable height P1 across bottom dead center BDC to feed-allowable height P5 can reliably be shortened.

As shown in FIG. 14, stand-by height P0 and monitoring position Pa are set such that when completion of feed of workpiece W has not been detected at the time point when slide 20 lowered from stand-by height P0 reaches monitoring position Pa, slide 20 can be stopped at stop position Pb higher than feed-allowable height P1. Even though an abnormal condition occurs during transportation of workpiece W, interference between workpiece W and a die can thus reliably be avoided.

An example in which the operation mode of slide 20 is set to the pendular motion has been described. Without being limited to the example in which the operation mode is set to the pendular motion, the concept in the embodiment described above is applicable to an example in which slide 20 moves upward and downward with respect to bolster 5 by rotating servo motor 121 alternately in forward and reverse directions during press working each time press working of workpiece W is performed. For example, the concept of the embodiment described above can be applied also to an example in which the operation mode is set to a reverse motion.

The press apparatus is not limited to those of the construction described in the embodiment, and the press apparatus may be constructed such that a plunger and a plunger holder are interposed between the connecting rod and the slide. An eccentric mechanism may have a crankshaft structure or a drum structure.

It should be understood that the embodiment disclosed herein is illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims rather than the description above and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

REFERENCE SIGNS LIST

2 main body frame; 4 bed; 5 bolster; 6 control panel; 10 press apparatus; 20 slide; 22A upper die; 22B lower die; 37 screw shaft; 38 connecting rod main body; 39 connecting rod; 40 controller; 42 CPU; 44 memory; 46 communication circuit; 48 input unit; 51 touch speed generator; 53 press motion generator; 55 feeder motion generator; 56 motion synthesizer; 58 execution unit; 60, 66 servo amplifier; 61 display; 62, 121 servo motor; 63 transportation roller; 64, 65 encoder; 68 feed completion detector; 70 remote controller; 72, 74 button; 76 enter button; 100 uncoiler; 110 main shaft; 110A eccentric portion; 115 main gear; 200 leveler feeder

Claims

1. A press system comprising:

a press portion including an electric motor, an eccentric mechanism configured to convert a rotary motion by the electric motor into a motion in an upward and downward direction, a slide to which an upper die is attachable, the slide being driven upward and downward with the eccentric mechanism being interposed, and a bolster to which a lower die is attachable, the press portion being configured to press work a workpiece by upward and downward movement of the slide with respect to the bolster;

a transportation portion configured to transport the workpiece; and

a controller configured to control the press portion and the transportation portion,

the controller being configured to have the slide driven upward and downward based on a prescribed press motion,

with a position of the slide where the workpiece can be transported without interfering with the upper die being defined as a feed-allowable height, and a position higher than the feed-allowable height and highest in the press motion being defined as a stand-by height,

the controller being also configured to have the workpiece transported while the slide is moving between the feed-allowable height and the stand-by height.

2. The press system according to claim 1, wherein

the controller is configured to start transportation of the workpiece by the transportation portion while the electric motor is decelerated.

3. The press system according to claim 1, wherein

the controller is configured to start transportation of the workpiece by the transportation portion while the slide is moving from the feed-allowable height to the stand-by height.

4. The press system according to claim 2, wherein

the controller starts deceleration of the electric motor after the slide passes the feed-allowable height as the slide moves upward.

5. The press system according to claim 1, wherein

the controller is configured to have the transportation portion complete transportation of the workpiece while the electric motor is accelerated.

6. The press system according to claim 1, wherein

the controller is configured to have the transportation portion complete transportation of the workpiece while the slide is moving from the stand-by height to the feed-allowable height.

7. The press system according to claim 5, wherein

the controller is configured to complete acceleration of the electric motor before the slide passes the feed-allowable height as the slide is moved downward.

8. The press system according to claim 5, wherein

the transportation portion includes a feed completion detector configured to detect completion of transportation of the workpiece,

the controller sets a monitoring position at a position higher than the feed-allowable height and lower than the stand-by height in the upward and downward direction of the slide, and

the controller sets the stand-by height and the monitoring position such that the slide can be stopped at a position higher than the feed-allowable height when completion of transportation of the workpiece has not been detected at a time point when the slide lowered from the stand-by height reaches the monitoring position.

9. The press system according to claim 1, wherein

the controller has the electric motor alternately rotate in forward and reverse directions each time press working is performed.

10. The press system according to claim 1, wherein

the electric motor is implemented by a servo motor.