JP2003320487A - Motor driven type link press - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor driven type link press which can be processed under a high press load and can improve the cycle time of the processing even when a motor of a relatively small output is used, is excellent in controllability, and can select the most suitable characteristic of a link mechanism corresponding to the kind of processing. <P>SOLUTION: The link press is equipped with the link mechanism 1 for converting a rotary motion to a straight-line motion and a ram 6 moving up and down for a press processing. The link mechanism 1 has a crankshaft 3, a crank member 2 having an eccentric shaft part 4, a swinging link 5, a connecting rod 7 and a constraint link 8. A rotation center changing means 51 for changing the rotation center E of the constraint link at the base end of the constraint link 8 for changing the descending speed of the ram. The rotation center changing means is composed of a turning member 51 in which the base end of the constraint link is turnably supported on an eccentric part, and an actuator 53 for turning the member 52, and controls the operation with the rotation control of a motor 13. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor-driven link press using a link mechanism as a slide drive mechanism.

[0002]

2. Description of the Related Art In mechanical punch presses, a crank mechanism is generally used as a slide drive mechanism for converting a rotating operation of a motor into an elevating operation of a ram. In addition, a flywheel is used to switch between driving and stopping the ram by connecting and disconnecting the rotation of the flywheel when the clutch is turned on and off. With the crank mechanism,
The curve of the ascending / descending speed of the ram is symmetrical with respect to the bottom dead center at the time of descending and ascending, and the descending speed and the ascending speed are the same. However, in general press working such as punching, when the ram descends, it is preferable to make it low speed because of the requirement of noise reduction and press load, but when ascending, there is no particular limitation, so it is desirable to be high speed. With a crank mechanism in which the descending speed and the ascending speed are the same, it takes more time than necessary to ascend, and the punching cycle time becomes long.
Recently, a servo motor is used as a drive source, and a ram is raised and lowered via a crank mechanism without providing a flywheel. If a servo motor is used, it is possible to freely change the speed during the stroke of the ram, to increase the descending speed and decrease the ascending speed. However, the capacity of the motor changes depending on the rotation speed, and in order to make the best use of the capacity of the motor, it is necessary to operate within the range of the optimum motor rotation speed according to the motor characteristics. By controlling the motor rotation speed to change the speed when the ram descends and when it rises, it is not possible to make full use of the capacity of the motor, and in order to obtain the necessary press load and increase the speed when climbing, A large motor is required.

Therefore, the inventor of the present invention has conducted various studies on what is slowed down when moving down and fast when moving up by selecting an appropriate slide mechanism. BACKGROUND ART Conventionally, a link press has been used for a long time as a slide mechanism used in a press device for plastic working such as cold extrusion and upsetting of metal (for example, Japanese Patent Publication No. 3-42159). The link press has a swing pin connected to a crank pin of a crank mechanism, a connecting rod connected to the swing link, and a restraint link connected to the swing link. The crankshaft is driven by a motor via a flywheel. According to the link press, the operation characteristic that the ram speed is slow when descending and fast when ascending is obtained by the action of the restraining link.

However, the conventional link press is used for improving the working quality of plastic working such as cold extrusion by utilizing a very slow descending operation near the bottom dead center thereof. There is no application example to a punch press that requires operating characteristics different from those of processing. Also, because it has a flywheel that stores the motor output as inertial energy,
Lack of controllability. In addition, since the link mechanism of the link press has a fixed operation characteristic, the optimum characteristic may not be obtained when the type of processing is changed, for example, when the magnitude of the load is changed. When punching, etc., the load is large when the plate thickness is thick or when the material is hard, so it is necessary to slow down the ram to drive it with a small output motor, but the load is small and there is a margin. If there is
The higher the descending speed, the better the processing quality. That is, in shearing such as punching, higher punching speed results in higher quality with less burrs. It is impossible to obtain an operation according to the type of processing as described above with the conventional link mechanism.

The object of the present invention is to enable processing by a high press load and improvement of the cycle time of processing even if a motor of relatively small output is used, and it is excellent in controllability. The present invention is to provide a motor-driven link press capable of selecting the optimum characteristics of the link mechanism. Another object of the present invention is to realize a means for changing the rotation center of the restraint link with a simple structure. Still another object of the present invention is to increase the degree of freedom in designing the means for changing the rotation center of the restraint link.

[0006]

The structure of the present invention will be described with reference to FIG. 1 corresponding to the embodiment. The motor-driven link press includes a motor (13) and the motor (13).
A link mechanism (1) for converting a rotary motion transmitted from a drive transmission system (14) into a linear motion, and a link mechanism (1) installed below the link mechanism (1) and moved up and down for press working by the linear motion. And a ram (6). The link mechanism (1) includes a crank member (2) having a crank shaft (3) and an eccentric shaft portion (4), and first to third connecting portions (P1 to P3) that rotatably connect to each other. A rocking link (5) having a first connecting part (P1) connected to the eccentric shaft part (4) of the crank member (2), and a second link having a first connecting part (P1). Connection part (P2)
And a connecting rod (7) whose both ends are connected to the upper end of the ram (6), and a third end of the swing link (5) whose base end is rotatably connected to the frame (9) And a restraint link (8) that is connected to the portion (P3) and restricts the swing of the swing link (5). The drive transmission system (14) transmits the rotational drive of the motor (13) to the crankshaft (3) so that the raising and lowering operation of the ram (6) can be controlled by controlling the rotation of the motor (13).
This drive transmission system (14) does not include a flywheel or other component for imparting inertia. Even if it has a speed reducer, the output shaft of the motor and the crank shaft are directly connected. May be. In the motor-driven link press, in the above-described structure, link rotation center changing means (51) for changing the position of the rotation center (E) of the base end of the restraint link (8) is provided.

The operation of this configuration will be described. Due to the rotation of the crankshaft (3), the swing link (5) revolves in the orbital motion of the eccentric shaft portion (4) along the orbit of the center of the eccentric shaft portion (4), and the restraint link (8) is connected so that the swing link (5) is reversed. Performs a combined action with the shaken rotation movement. The revolving motion of the rocking link (5) causes the connecting rod (7) connected thereto to ascend and descend, but because of the above-described rotation movement, the lower end position of the connecting rod (7), that is, the ram position ascends and descends. The velocity curve does not become a quasi-sine curve, but becomes asymmetric between the descent and the ascent. Which of the descending speed and the ascending speed becomes faster is determined by a combination of various elements such as the fulcrum position and length of the restraint link (8). Therefore,
By properly designing each element, the restraint link (8) swings so that the descending motion of the ram (6) when the crankshaft (3) is rotated in one direction at a constant speed is slower than the ascending speed. The swing of the dynamic link (5) can be restricted. In this way, by lowering the descending speed, it is possible to perform processing with a high press load even when using the motor (13) having a relatively small output, and the ascending speed becomes faster, so that the machining cycle time is improved. To do. Since the above-mentioned speed change is given while the motor speed remains constant, for example, by interposing a speed reducer having an appropriate speed reduction ratio, it is possible to operate at the motor rotation speed that maximizes the motor output according to the motor characteristics. This also makes it possible to use the motor (13) having a small output.
Further, the motor (13) and the crankshaft (3) have a drive transmission system (1) in which an inertia imparting system such as a flywheel is not interposed.
4), the controllability such as changing the ram speed by controlling the rotation speed of the motor (13) and stopping during the stroke is excellent.

Further, link rotation center changing means (5) for changing the position of the rotation center (E) of the base end of the restraint link (8).
Since 1) is provided, the characteristics such as the ram lowering speed in the link mechanism (1) can be changed. Therefore, in the case of machining with a heavy load, the descending speed is slowed down to reduce the torque, and in the case of machining with a light load, the machining speed is comparatively increased to improve the machining quality. The optimum characteristics of the link mechanism (1) can be selected. In the present invention, when the rotation center (E) of the restraint link (8) is changed, after confirming that the changed position is fixed, the motor (13) is driven to perform the machining. A processing control means (61) for starting may be provided. In that case, it is safe because the processing is prevented from being started in the state where the change or fixing is incomplete.

The link rotation center changing means (51) is
A rotating member (52) that rotatably supports the base end of the restraint link (8) on the eccentric part (12), and the rotating member (5).
It may be composed of an actuator (53) for rotating 2). When the rotating member (52) having the eccentric portion (12) is used as described above, the base end position of the restraint link (8) can be changed only by rotating the rotating member (52).
The link rotation center changing means (51) can have a simple structure.

When the machining control means (61) is caused to change the link rotation center changing means (51), the crankshaft (3) is rotated by a predetermined angle by driving the motor (13). It is preferable to provide a changeable motor angle control means (63). The restraint link (8), when changing the rotation center (E) of the base end,
Since the tip end is connected to the third connecting portion (P3) of the swing link (5), if the base end position of the restraint link (8) is changed without significantly moving the ram (6) up and down, It is necessary to change on an arc centered on the third connecting portion (P3). In order to change the position on such an arc, the structure of the link rotation center changing means (51) is limited. Motor angle control means (63) corresponding to the above change
, The rotation center (E) of the base end of the restraint link (8)
Even if the position of the motor is changed along an arbitrary path, the crankshaft (3) is rotated by an amount corresponding to the swing of the swing link (5) and the raising and lowering of the ram (6) accompanying the change, that is, the motor. By rotating the crankshaft (3) by a predetermined angle by (13), the rotation center position of the restraint link (8) can be changed without largely changing the ascending / descending position of the ram (6). That is, it is possible to change the rotation center position of the restraint link (8) while suppressing the elevation of the ram (6) within an appropriate range.
Therefore, the structure of the link rotation center changing means (51) is not limited, the degree of freedom in design is increased, and the structure can be simplified.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram combining a link mechanism and a block diagram showing a conceptual configuration of a control system in this motor-driven link press. The control system will be described later. This motor-driven link press has a motor 13 and
A link mechanism 1 for converting a rotary motion transmitted from the motor 13 via a drive transmission system 14 into a linear motion, and a ram 6 installed below the link mechanism 1 and moved up and down for press working by the linear motion. With. The link mechanism 1 includes an eccentric shaft portion 4 which is eccentric with respect to the axis of the crankshaft 3.
The crank member 2 has a swing link 5, which is connected to the eccentric shaft portion 4, a connecting rod 7, and a restraining link 8. The crankshaft 3 is rotatably installed on the frame 9 and serves as a shaft that receives a rotational driving force. The eccentric shaft portion 4 has a larger diameter than the crankshaft 3. The eccentric shaft portion 4 may have a smaller diameter than the crankshaft 3 and may be integrated with the crankshaft 4 via a crank arm (not shown), instead of having the large diameter as described above. The ram 6 is a member that raises and lowers a press working portion such as a punch tool.
It is installed so that it can be raised and lowered through the guide member 10. The ram 6 is directly below the crankshaft 2.

The swinging link 5 has first to third connecting portions P1 to P3, and the crank member 2 is connected to the first connecting portion P1.
Is connected to the eccentric shaft portion 4. Each connecting portion P1-3
Each of them is a connecting portion for rotatably connecting and is located at each vertex of the triangle T, as schematically shown in FIG. This triangle T is an arbitrary triangle in a plane perpendicular to the axis of the crankshaft 3. In FIG. 1, the connecting rod 7 is the second connecting portion P of the swing link 5.
The upper end is connected to 2 and the lower end is rotatably connected to the upper end of the ram 6 via a pin 11. The restraint link 8 has a base end rotatably supported by the frame 9 via a fulcrum shaft 12,
The tip is connected to the third connecting portion P3 of the swing link 5. The restraint link 8 is arranged such that the swing center, which is the axial center of the fulcrum shaft 12, and the third connecting point P3 are distributed to both sides of the crankshaft 3. The both sides are both sides in a plane perpendicular to the axis of the crankshaft 3, and both sides in the left-right direction and both sides in the front-rear direction with respect to the entire motor-driven link press. good.

As shown in FIGS. 4 and 5, the crankshaft 3 has a drive transmission system 14 connected to an output shaft (not shown) of the motor 13.
Are connected via. The drive transmission system 14 is the motor 1
It is assumed that the rotation drive of the ram 6 can be controlled by the rotation control of the motor 3, and the rotational drive of the motor 13 can be transmitted to the crankshaft 3. Therefore, the drive transmission system 14 is a means for transmitting the torque of the motor 13 without interposing components such as a flywheel for imparting inertia. In this embodiment, the drive transmission system 14 includes a speed reducer 15 and a coupling 16 that connects the output shaft of the speed reducer 15 to the crankshaft 3.
A servo motor is used as the motor 13. The speed reducer 15 and the motor 13 may be integrated with each other to form a motor with a speed reducer.

FIG. 2 shows a broken side surface of the link mechanism 1.
The crankshaft 3 extends on both sides of the eccentric shaft portion 4, and is rotatably supported on the frame 9 on both sides via bearings 17 such as journal bearings. In the swinging link 5, the inner diameter surface of the connecting hole forming the first connecting portion P1 is fitted to the outer periphery of the eccentric shaft portion 4 via the liner 18. Second of swing link 5
The connecting portion P2 and the connecting rod 7 are connected by a connecting pin 19.

As shown in FIG. 1, the frame 9 is provided with link rotation center changing means 51 for changing the position of the rotation center E of the base end of the restraint link 8. As shown in FIG. 8 and FIG. 8, the link rotation center changing means 51 includes a rotating member 52 provided with the fulcrum shaft 12 as an eccentric portion, and an actuator 53 for rotating the rotating member 52. . The rotating member 52 has a shaft portion 52 that is aligned with the center position.
a (FIG. 9) and is rotatably supported by the shaft 52a on the frame 9 via a bearing (not shown). The base end of the restraint link 8 is rotatably supported by the fulcrum shaft 12, and when the turning member 52 is turned, the position of the fulcrum shaft 12 is changed and the turning center E of the restraint link 8 is changed. change. A pair of rotating members 52 are provided coaxially, and the fulcrum shaft 12 is provided across the rotating members 52 on both sides. As the actuator 53, for example, a fluid pressure cylinder such as an air cylinder, a motor, or an electromagnetic solenoid is used.

Locking means 54 for fixing the rotation center E of the restraint link 8 at each change position is provided for the link rotation center changing means 51. The locking means 54 includes an engaged portion 55 provided on the rotating member 52 and the engaged portion 55.
And a drive source 57 for engaging and disengaging the lock member 56. The engaged portion 55 is a concave portion provided on the outer peripheral surface of the rotating member 54, and the lock member 56 is a pin-shaped member that can advance and retreat. The engagement / disengagement drive source 57 includes a fluid pressure cylinder or an electromagnetic solenoid, and is installed on the frame 9. The engaged parts 55 of the rotating member 52 are provided at two positions that are separated from each other in the circumferential direction, and the lock member 56 can be engaged with the engaged parts 55 facing each other by the rotation of the rotating member 52. Is. Therefore, the rotation center E of the restraint link 8 can be fixed at two positions. The engaged parts 55 are provided at three or more places, and the rotation center E is set to 3
It may be fixed at more than one place.

As shown in FIG. 5, the frame 9 is an independent link part frame that supports the link mechanism 1, and is attached to the tip of the upper frame part 22a of the main body frame 22. The link frame 9 has a box shape. The frame 9 supports both ends of the crankshaft 3 by a support plate 9b provided on the inner surface of the mounting substrate 9a and a counter plate 9c facing the support plate 9b. The frame 9 has a motor support member 23.
The motor 13 is installed on the motor support member 23. Therefore, the motor 9 is connected to the link mechanism 1
Together with the link frame 9 in which the
It is removably attached to the 2. Body frame 2
2 has a C-shaped side surface, and an opening portion 24 serving as a throat portion thereof is a space into which a plate work and a tool support enter. The body frame 22 has a pair of opposing side plates, and only one opposing side plate is shown in FIG. In the upper frame portion 22a, opposite side plates on both sides are joined to each other by an upper frame lower surface plate 25 and an intermediate reinforcing plate 26.

12 and 13 are a plan view and a side view of the whole motor-driven link press equipped with the link mechanism 1 of FIG. 1, respectively. The body frame 22 is the body cover 3
It is covered with 0. The link mechanism 1 is attached to the body frame 22.
Besides, a tool supporting means 28 and a work feeding means 29 are installed. The tool supporting means 28 mounts a plurality of punch tools 31 and die tools 32, and arbitrary tools 31, 32 (FIG. 13) at the press working position Q by the ram 6.
The index can be calculated. Tool support means 28
Is composed of upper and lower turrets 28a and 28b on which a punch tool 31 and a die tool 32 are mounted, respectively. The work feeding means 29 moves the plate work W on the table 33,
This is means for moving an arbitrary portion in the two orthogonal axis directions (X axis, Y axis) so that it comes to the press working position Q. The work feeding means 29 is a carriage 34 that moves back and forth (Y-axis direction).
And a cross slide 35 mounted on the carriage 34 and moving left and right (X-axis direction).
The plate work W is gripped by the plurality of work holders 36 provided in the. By moving the carriage 34 back and forth and moving the cross slide 35 left and right, the plate material work W in the biaxial direction is obtained.
Is sent.

The operation of the above configuration will be described. The link mechanism 1 of FIG. 1 performs the following operation, as can be seen by referring to the schematic view of FIG. 7. When the crank shaft 3 is rotated by driving the motor, the center of the eccentric shaft portion 4 of the crank member 2 is, as shown in FIG. 7, a circular orbit C1 centered on the shaft center of the crank shaft 3.
Draw. The oscillating link 5 includes the eccentric shaft portion 4 and the first connecting portion P.
Since it is rotatably connected at 1, the above-mentioned circumferential orbit C1
Perform an orbital movement in line with. Since the swing link 5 is connected to the restraint link 8 by the third connecting portion P3, its operation is restricted, and the first connecting portion P1 is associated with the revolving movement.
Performs a rotational movement that is swung in the normal and reverse directions. Due to this combined movement of the revolution movement and the rotation movement, the second connecting portion P2, which is the connecting portion of the swinging link 5 with the connecting rod 7, is
As shown in the figure, it moves along an oblique elliptical orbit C2.
The ram 6 is supported so that it can be raised and lowered only, and is connected to the second connecting portion P2 of the swing link 5 via the connecting rod 7, so that the second connecting portion P2 draws an elliptical orbit. Moves up and down by. As shown by the curve H in FIG. 9, the relationship between the crank angle and the displacement of the ram 6 causes the ascending / descending speed to be asymmetric between the descending and the ascending. Further, the crank angle θ _BDC when the ram 6 reaches the bottom dead center BDC is a position deviated from 180 °. A curve J also shown in the figure shows the vertical displacement of the ram in a general crank mechanism and is symmetrical.

Elements that affect the operation of the link mechanism 1 are the following eight elements shown in FIG. The crank length (eccentricity) r, the length w of the restraint link 8, the length L of the connecting rod 7, the opening angle α between the connecting portions P2 and P3 of the swing link 5, and the connecting portion P1 of the swing link 5. Connection part P
The lengths a and b between 2 and P3, and the X coordinate Ex and the Y coordinate Ey of the rotation center E of the restraint link 8. The center of coordinates is the axis of the crankshaft 3. As a condition for establishing the link mechanism 1, the rotation center of the crankshaft 3 and the connecting portion P1
-Connecting part P3-A four-joint rotary chain that is established by using the fulcrum shaft 12 of the restraint link 8 as a connecting point between the joints must be established, and the following equations must be satisfied with the shortest joint being the crank length r. is there. As A = √ (Ex ^ 2 + Ey ^ 2), r + a ≦ w + A r + w ≦ a + A r + A ≦ a + w This is known as Grashof's theorem. , The displacement curve of the ram 8 can be freely designed.
The link rotation center changing means 51 of FIG. 1 changes the position of the rotation center E to change the values of Ex and Ey, and changes the displacement curve of the ram 8 as described later.

Which of the descending speed and the ascending speed becomes faster is determined by the combination of the motor rotation direction and the above-mentioned respective elements. Therefore, assuming that the motor rotation direction is constant, by appropriately designing the respective elements, it is possible to perform an operation in which the descending speed of the ram 6 when the motor 13 rotates at a constant speed becomes slower than the ascending speed. By slowing the descending speed in this way, machining can be performed with a high press load even when the motor 13 having a relatively small output is used, and the ascending speed is increased, so that the machining cycle time is improved. As shown in FIG. 10 by comparing the crank type press and the link type press, when the cycle time is “10”, the crank type both has a descending time and an ascending time of “5” as shown in FIG. However, in the link type, it is possible to design so that the falling time is “7” and the rising time is “3” as shown in FIG. When the link mechanism 1 is designed in this way, the ram speed of the descending operation becomes 5/7 as slow as that of the crank type, and the press load becomes 7/5 as much, and even if the same motor is used, 40%
The press load can be improved. Since no work is performed when the ram 6 is raised, even if the force is weak, it does not affect the machining.

Further, since the above-mentioned speed change is given while the motor speed is kept constant, the speed reducer 15 having an appropriate deceleration ratio is provided.
By interposing (FIG. 4), it is possible to operate at the motor rotation speed that maximizes the motor output according to the motor characteristics. This also makes it possible to use the motor 13 with a small output.
Further, since the motor 13 and the crankshaft 3 are connected via the drive transmission system 14 in which an inertia imparting system such as a flywheel does not intervene, the controllability of changing the ram speed by controlling the rotational speed of the motor 13 is excellent.

When the motor 13 is a servo motor,
Since the motor speed can be freely changed, the speed during the up-and-down stroke of the ram 6 can also be changed, and machining according to various requests can be performed. That is, the crank member 2 is used as a speed curve when the motor 13 is rotated at a constant speed.
Based on the speed curve according to the operation of the link mechanism 1 composed of the rocking links 5, the restraint links 8 and the like, the speed when the punch tool 31 comes into contact with the plate work W is changed by changing the motor speed. It is also possible to further reduce the noise to further reduce the noise, and to further increase the speed at the time of rising. Further, the ram 6 can be stopped at an arbitrary height.

In this motor-driven link press,
When punching, as shown in FIG. 9, the punching section M, which is a section used for punching the plate material work W, needs to be an intermediate section of the descending process of the ram lifting stroke. The intermediate section, which is the punching section M, is a section in which the curve H of the displacement of the ram 6 with respect to the crank angle is substantially linear. The lower limit position H ₁ of the punching section M is slightly above the die height DH. In the link press, if the motor speed is constant, as can be seen from the ram displacement curve H in the same figure, the curve becomes a gentle curve near the top dead center TDC, becomes a straight line in the middle section, and again near the bottom dead center BDC. It becomes a gentle curve. The speed near the bottom dead center BDC is the slowest, and therefore the largest press load is obtained near the bottom dead center BDC. In the conventional linking press for forming, a large press load near the bottom dead center BDC is used for forming. However, in the case of punching, a stroke is required below the lower surface of the plate work W in order to surely drop the punch residue. On the other hand, if the punching section M is the middle section of the stroke, a sufficient stroke can be obtained below the lower surface of the plate work W, and the punching scraps can be reliably dropped, and the originally small punch load in the middle section. Link mechanism 1
Can be supplemented with. In other words, for this reason, the vicinity of the bottom dead center BDC where a large press load can be obtained cannot be used, but it can be used more efficiently than the conventional symmetrically operating crank mechanism. Punching requires a large press load and high-speed processing. Further, in punching, the higher the punching speed, the better the processing quality, and the punching section M
When is the intermediate section, the punching speed required for processing quality can be obtained without waste. In this way, when applied to a punch press, the action of the link mechanism 1 can be effectively used in a usage pattern different from that of the conventional link press for molding.

Next, the change in the link characteristics when the rotation center E of the restraint link 8 is changed will be described. In the case of the position and dimensional relationship of each part of the link mechanism 1 shown in FIG. 1, when the rotation center E is located above the rotation member 52 as shown in FIG. 9A, according to the analysis result, The ram displacement curve shown by curve HA in FIG. 11 is obtained. This is shown in FIG.
It is the same as the ram displacement curve H shown in FIG. Note that FIG.
Shows the crank angle at the bottom dead center of the ram displacement curve HA as a position of 180 ° for the sake of comparison. The torque in the case of the ram displacement curve HA can be obtained for a long period in which the torque is substantially constant when descending, as indicated by the curve TA in the figure.
On the other hand, when the rotation center E is located lower left than the original position as shown in FIG. 8B, the ram displacement curve shown by the curve HB in FIG. 11 is obtained, which is higher than the curve HA before the change. The speed when descending becomes faster. When the ram displacement curve HB is reached, as shown by the curve TB in the figure, the torque tends to greatly change as the ram descends when it descends.

According to the link rotation center changing means 51, by changing the rotation center E, the two ram displacement curves HA and HB can be freely selected. When a ram displacement curve HA with a slow descending speed is used, when a large work load is to be performed, such as when the plate work W has a large plate thickness, is made of a hard material, or is processed with a punch tool having a large outer diameter. In addition, there is an advantage that processing can be performed by the motor 13 having a small output. When the ram displacement curve HB with a fast descending speed is used, the punching can be performed at high speed when the plate work W can be processed with a small load, such as when the plate work W has a small thickness. Therefore, high quality machining with less burr can be performed. There is. Thus, the link rotation center changing means 51 can change the characteristics of the link mechanism 1 to select the optimum characteristics according to the type of processing. The link characteristic control means 6 for controlling the link rotation center changing means 51 according to the type of processing.
7 (FIG. 1) is preferably provided. The link characteristic control means 67 is provided in, for example, the processing control means 61 described later. In the link characteristic control means 67, the type of processing is judged based on predetermined processing type identification information. The machining type identification information may be, for example, a predetermined command or information in the machining program 65, and the machining control means 6
It may be a predetermined command or information given from one host controller (not shown), or may be a predetermined command or information inputted by an operator from an operation panel (not shown) or the like. The link characteristic control means 67
For example, it has a correspondence table (not shown) between the predetermined machining type identification information and the position of the rotation center E controlled by the link rotation center changing means 51, and collates the machining type identification information with the above correspondence table. Then, the position of the rotation center E is controlled. The processing type identification information may be a combination of a plurality of pieces of information, for example, a combination of plate thickness and processing peripheral length.

The control system will be described. Processing control means 61
Is a device that controls the entire motor-driven link press, and includes a computer-based numerical control device that is controlled by a machining program 65 and a programmable controller. When the rotation center of the restraint link 8 is changed, the processing control means 61 has a control function of driving the motor 13 and starting it after confirming that the changed position is fixed. This function and the like will be described.

The processing control means 61 includes a link characteristic control means 67, a change command means 62, and a change-compatible motor angle control means 6
3 and the lock confirmation processing permission means 64. The change command means 62 is a part or the whole of the link characteristic control means 67. The change command means 62 recognizes the type of machining by a predetermined command in the machining program 65,
The link rotation center changing means 51 is controlled to change the rotation center E of the restraint link 8 according to the type of processing. In the change command means 62, the types of machining are divided into two types, large load machining and small load machining. In the case of heavy load machining, the rotation center E is located at a position corresponding to a large load (FIG. 8). (The position shown in (A)), and in the case of light load machining, the rotation center E corresponds to the light load (the position shown in FIG. 8B).
And Further, the lock means 54 is unlocked before the operation of the link rotation center changing means 51, and the lock means 54 is locked after the change is completed. The change command means 62 may be configured to cause the link rotation center changing means 51 to change the rotation center E by operating the switch 66, and the above change can be made by both the machining program 65 and the switch 66. It may be one that can be operated.

The change corresponding motor angle control means 63 is means for driving the motor 13 to rotate the crankshaft 3 by a predetermined angle when the link rotation center changing means 51 performs the changing operation. . The predetermined angle is determined by changing the position of the rotation center E so that the swing link 5 swings and the ram 6 moves up and down, so that the vertical position of the ram 6 does not change much before and after the change. Is the angle that causes the rotation of.

The lock confirmation processing permitting means 64 prohibits the drive of the motor 13 when the rotation center E of the restraint link 8 is changed by the link rotation center changing means 51, and the changed position is fixed. After confirming that, the motor 13
Is a means for permitting the start of driving. Specifically, the rotation member 52 of the link rotation center changing unit 51 rotates, and the lock member 56 of the locking unit 54 rotates the engaged portion 5 of the rotation member 52.
When it is confirmed that it is engaged with 5, the lock confirmation processing permission means 64 permits the drive of the motor 13. The engagement of the lock member 56 or the engaged portion 55 is recognized by a signal detected by the detection means 58 that the lock driving means 57 has moved to a predetermined position. The detection unit 58 may be omitted, and the drive of the motor 13 may be permitted after a predetermined time has elapsed after the change command unit 62 outputs a lock operation command to the lock drive unit 57. The non-permission by the lock confirmation processing permission means 64 is, for example, the change command means 6
2 when the lock output command is issued to the lock means 54.

The control operation by the machining control means 61 when changing the rotational center position will be described. When performing high-load machining, the change command means 62 causes the link rotation center changing means 51 to set the rotation center E of the restraint link 8 to a position corresponding to a large load in response to a predetermined command of the processing program 65 or a signal from the switch 66. (The position of FIG. 8A). In this position, the ram displacement curve HA shown in FIG. 11 is obtained as described above, the descending speed of the ram 6 is slow, and punching can be performed with low torque. When performing light load machining, the change command means 6 is issued by a predetermined command of the machining program 65 or a signal from the switch 66.
2, the link rotation center changing means 51 sets the rotation center E of the restraint link 8 to the small load corresponding position (position in FIG. 8B). In this position, the ram displacement curve HB shown in FIG. 11 is obtained, and the ram 6 descends at a high speed, so that high quality punching can be performed.

When the change command means 62 causes the link rotation center changing means 51 to perform the changing operation, first, the lock of the rotating member 52 by the locking means 54 is released, and then the rotating member 52 is predetermined by the actuator 53. Rotate at an angle. By this rotation, as shown in FIG. 8B, another engaged portion 55 of the rotation member 52 corresponds to the lock member 56. Then, the lock member 55 is engaged with the engaged portion 55 by the locking means 54, and the rotating member 52 is locked so as not to rotate. By locking the rotating member 52 with the locking means 54 in this manner, the rotation center E of the restraint link 8 is prevented from moving due to a load during processing. The lock confirmation processing permission means 64 disables the driving of the motor 13 by the processing control means 61 at the time of unlocking the rotating member 52, and the detection means 58 detects that the locking means 54 is in the locked state. Then, the drive of the motor 13 is allowed. As described above, since the operation of the motor 13 is permitted and the punching is performed after the position of the rotation center E is fixed, the punching is performed in the lock failure state or the incomplete positioning of the rotation center E. Is prevented and safety is secured. The above-described change operation has been described in the case of changing from the large load position to the small load position, but changing from the small load position to the large load position only requires that the rotating member 52 rotate in the opposite direction. , Perform the same operation as above.

Further, when the rotation member 52 is rotated by the link rotation center changing means 51, the change corresponding motor control means 63 causes the motor 13 to rotate the crankshaft 3 by a predetermined angle. That is, since the tip end of the restraint link 8 is connected to the third connecting portion P3 of the swing link 5 when the rotation center E of the base end is changed, the restraint link 8 does not move up and down the ram 6. When it is attempted to change the base end position of (3), it is necessary to change it on an arc centered on the third connecting portion P3. In order to change the position on such an arc, the structure of the link rotation center changing means 51 is limited, and the fulcrum shaft 1 is attached to the rotating member 52 in this embodiment.
A configuration in which 2 is provided eccentrically cannot handle this. When the change-compatible motor angle control means 63 is provided, even if the position of the rotation center E of the base end of the restraint link 8 is changed along an arbitrary path, the swing link 5 swings and the ram 6 moves up and down due to the change. By rotating the crankshaft 3 by an amount corresponding to, that is, by rotating the crankshaft 3 by a predetermined angle by the motor 13, the swing center E of the restraint link 8 can be changed without significantly changing the vertical position of the ram 6. The position can be changed. Therefore, the operation of the link rotation center changing means 51 is not limited, the degree of freedom in designing the link rotation center changing means 51 is increased, and the fulcrum shaft 12 is eccentrically provided on the rotating member 52. it can.

[0034]

Since the motor-driven link press of the present invention employs a link mechanism having a crank member, a swinging link, a connecting rod, and a restraining link, a high press load can be obtained even if a motor having a relatively small output is used. It is possible to improve the processing time and the processing cycle time. Also, while adopting the link mechanism, a drive transmission system for transmitting the rotational drive of the motor to the crankshaft of the link mechanism was used to controllably transmit the raising and lowering motion of the ram by controlling the rotation of the motor, that is, the flywheel. Since a drive transmission system that does not include parts for the purpose of imparting inertia such as is used, controllability is also excellent. Also,
Since the link rotation center changing means for changing the position of the rotation center of the base end of the restraint link is provided, the optimum characteristics of the link mechanism can be selected according to the type of processing. When the link rotation center changing means is composed of a rotating member that rotatably supports the base end of the restraint link on an eccentric part and an actuator that rotates the rotating member, the link rotation center changing means. Can have a simple configuration. When the processing control means is provided with a change corresponding motor angle control means for rotating the crankshaft by a predetermined angle by driving the motor when changing the link rotation center changing means, when the ram is moved up and down. Since the rotation center of the restraint link is changed without largely changing the position, the degree of freedom in design can be obtained, and the link rotation center changing means can have a simple structure.

[Brief description of drawings]

FIG. 1 is an explanatory view in which a broken front view of a link mechanism in a motor-driven link press according to an embodiment of the present invention and a block diagram showing a conceptual configuration of a control system are combined.

FIG. 2 is a cutaway side view of the link mechanism.

3A and 3B are respectively a front view and a side view of the link mechanism.

FIG. 4 is a side view showing a connected state of the link mechanism and the motor.

FIG. 5 is a perspective view showing a portion where the link mechanism and the motor are installed in a main body frame.

FIG. 6 is a perspective view of the link mechanism.

FIG. 7 is an explanatory diagram of an operation model of the link mechanism.

8A and 8B are cutaway front views showing respective operating states of the link rotation center changing means.

FIG. 9 is a graph comparing the relationship between the crank angle and the ram displacement of the link mechanism and the crank type press.

FIG. 10 is a graph comparing ram displacement processes of the link mechanism and the crank type press.

FIG. 11 is a graph showing a relationship between a crank angle, a ram displacement, and a torque in the link mechanism at each rotation center position of the restraint link.

FIG. 12 is a plan view showing the entire motor-driven link press of the same embodiment.

FIG. 13 is a side view showing the entire motor-driven link press.

[Explanation of symbols]

1 ... Link mechanism 2 ... Crank member 3 ... crankshaft 4 ... Eccentric shaft 5 ... Swing link 6 ... Ram 7 ... Connecting rod 8 ... Restraint link 9 ... Frame 10 ... Guide member 11 ... pin 12 ... fulcrum shaft (eccentric part) 13 ... Motor 14 ... Drive transmission system 15 ... reducer 51 ... Link rotation center changing means 52 ... Rotating member 53 ... Actuator 54 ... Locking means 61 ... Processing control means 63 ... Changeable motor angle control means 67 ... Link characteristic control means

Claims (3)

[Claims] 1. A motor, a link mechanism for converting a rotary motion transmitted from the motor via a drive transmission system into a linear motion, and a link mechanism installed below the link mechanism for press working by the linear motion. The link mechanism includes a ram that moves up and down, and a crank member having a crank shaft and an eccentric shaft portion, and first to third connecting portions that rotatably connect the crank member and the crank member. A swing link having a first connecting portion connected to the eccentric shaft portion of the crank member; a connecting rod having both ends connected to the second connecting portion and the upper end of the ram; and a base end having a frame. A restraining link for pivotally controlling the swing of the swing link, the tip being coupled to the third linking portion of the swing link so as to control the rotation of the motor. Rum's rise The rotation drive of the motor is transmitted to the crankshaft so that the descending operation can be controlled, and link rotation center changing means for changing the position of the rotation center of the base end of the restraint link is provided. Motor driven link press. 2. The link rotation center changing means includes a rotation member that rotatably supports a base end of the restraint link on an eccentric portion, and an actuator that rotates the rotation member. The motor-driven link press described. 3. A change-adaptive motor angle control means for rotating the crankshaft by a predetermined angle by driving the motor when changing the link rotation center changing means is provided. The motor-driven link press described in 2.