JP2003320484A - Motor driven type link press - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a link press which is capable of working with a high press load and improving the cycle time of working and is excellent in controllability even when using a relatively small output motor. <P>SOLUTION: A link mechanism 1 for converting rotating motion to linear motion and a ram 6 vertically moved by the linear motion for press working are provided. The link mechanism 1 has a crank member 2 with a crankshaft 3 and an eccentric shaft part 4, a rocking link 5, a connecting rod 7, and a restricting link 8. The rocking link 5 has a first, a second, and a third connection part P1, P2, P3 and is connected to the eccentric shaft part 4 of the crank member 2 through the connection part 1. The connecting rod 7 is connected to the second connection part P2 and the ram 6. The restricting link 8 is turnably supported by a frame 9 and connected to the connection part P3 to restrict rocking of the rocking link 5. A driving transmitting system 14 which transmits driving from a motor 13 to the crankshaft 3 in the link mechanism 1 is provided. The system 14 transmits the driving in a manner that it controls the vertical motion of the ram 6 by controlling the rotation of the 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 applied to punch presses and other press machines.

[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.

An object of the present invention is to provide a motor-driven link press which is capable of processing by a high press load and improving the cycle time of the processing even when a motor having a relatively small output is used and which is excellent in controllability. Is to provide. Another object of the present invention is to enable various processing by free speed control while utilizing the advantages of the link press. Still another object of the present invention is to enable the punch dust to be reliably dropped when applied to a punch press.

[0006]

A motor-driven link press according to the present invention includes a motor, a link mechanism for converting a rotary motion transmitted from the motor through a drive transmission system into a linear motion, and the link mechanism described above. And a ram installed below and moved up and down for press work by the linear motion. The link mechanism has a crank member having a crankshaft and an eccentric shaft portion, and first to third connecting portions that rotatably connect to each other so as to be located at respective vertices of a triangle. A rocking link whose part is connected to the eccentric shaft part of the crank member, a connecting rod whose both ends are connected to the second connecting part and the upper end of the ram, and a base end of which is rotatably connected to the frame. The tip of the oscillating link is connected to the third connecting portion of the oscillating link so that the descending motion of the ram when the crankshaft is rotated in one direction at a constant speed is slower than the ascending speed. And a restraint link that regulates swinging. The drive transmission system transmits the rotational drive of the motor to the crankshaft so that the raising / lowering operation of the ram can be controlled by controlling the rotation of the motor. This drive transmission system does not include a component such as a flywheel for the purpose of imparting inertia, and may have a speed reducer or may directly connect the output shaft of the motor and the crankshaft. .

The operation of this configuration will be described. Due to the rotation of the crankshaft, the swing link performs a combined operation of an orbital motion along the swirl orbit of the shaft center of the eccentric shaft portion and a rotation motion that is swung forward and backward due to the connection of the restraint link. Due to the revolving motion of the rocking link, the connecting rod connected to it moves up and down.However, because of the above-mentioned rotation motion, the lowering position of the connecting rod, that is, the ram position lifting speed curve is not a quasi-sine curve. Instead, it becomes asymmetrical when descending and when ascending. 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 the length of the restraint link. Therefore, by properly designing each element, the restraint link regulates the swing of the swing link so that the descending motion of the ram when the crankshaft is rotated in one direction at a constant speed is slower than the ascending speed. can do. In this way, by slowing the descending speed, it is possible to process with a high press load and to increase the ascending speed even if a motor with a relatively small output is used.
The processing cycle time is improved. 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 enables the use of a low power motor. Further, since the motor and the crankshaft are connected via a drive transmission system such as a flywheel in which an inertia imparting system does not intervene, the controllability such as changing the ram speed by controlling the rotational speed of the motor is excellent.

When the above motor is a servo motor,
Since the motor speed can be freely changed, the speed can be changed during the up-and-down stroke of the ram, and machining according to various needs can be performed. That is, as the speed curve when the motor is rotated at a constant speed, the speed curve based on the operation of the link mechanism composed of the crank mechanism, the swing link, the restraint link, etc. is basically used, and the motor speed is changed. For example, it is possible to further reduce the speed when the punch tool comes into contact with the work for further noise reduction, or to further increase the speed when the punch tool rises.

The motor-driven link press of the present invention is
It may be a punch press. In that case, the section used for punching the plate work during the lifting stroke of the ram is the intermediate section of the lowering process of the lifting stroke. The setting of the section used for this punching is determined by the relationship between the table height on which the plate work is placed, the ram position, the installation height of the punch and die tool, and the like. In this way, when the intermediate section of the ram elevating stroke is the punching section, a sufficient stroke can be obtained further downward from the lower surface of the plate work, and the punching dust can be reliably dropped.

[0010]

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 cutaway front view of a link mechanism in this motor-driven link press. The motor-driven link press is provided with a motor 13, 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 installed below the link mechanism 1. And a ram 6 that moves up and down for press working by linear movement. The link mechanism 1 includes a crank member 2 having an eccentric shaft portion 4 which is eccentric with respect to the axis of the crank shaft 3, a swing link 5 connected to the eccentric shaft portion 4, a connecting rod 7, and a restraining link 8. Have. 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 4. The eccentric shaft 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. Ram 6 is
It is a member for raising and lowering a press working portion such as a punch tool, and is installed on the frame 9 via a guide member 10 so as to be able to move up and down. The ram 6 is directly below the crankshaft 2.

The swing 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. In the restraint link 8, the swing center that is the axis of the fulcrum shaft 12 and the third connecting portion P3 are arranged separately on 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.

By changing the length of the connecting rod 7 in two stages of long and short at the intermediate portion in the length direction, the lower end position of the ram 6 is set to the upper shift position and the lower shift position. Ram shift mechanism 20 for switching
have. The ram shift mechanism 20 has a shift drive source 21 including a cylinder device and the like.
The shift position is switched by driving 1. As will be described in detail later, this switching of the shift position is used to enable the tool exchange while lowering the top dead center of the punch tool when driven by the ram 6 compared to the standby punch tool on the turret. To be The reason for lowering the top dead center of the punch tool is to improve the cycle time and to allow the crank member 2 with a small eccentricity to be adopted, thereby reducing the motor torque. The torque is reduced by both the link mechanism 1 and the ram shift mechanism 20. Eccentric shaft part 4 of crank member 2
Twice the amount of eccentricity is the distance between the lower shift position and the bottom dead center, that is, the lifting stroke of the punch tool and the ram 6.

As shown in FIG. 5, the frame 9 is an independent link portion frame that supports the link mechanism 1, and is attached to the tip of the upper frame portion 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 its opening 24 is
It is the space where the plate work and tool support enter. The body frame 22 has a pair of opposing side plates, and only one opposing side plate is shown in FIG. Upper frame part 2
In 2a, the opposite side plates on both sides are the upper frame lower surface plate 2
5 and the intermediate reinforcing plate 26 are joined to each other.

10 and 11 are a plan view and a side view, respectively, of an example in which the motor-driven link press having the link mechanism 1 of FIG. 1 is applied to a punch press. The body frame 22 is covered with a body cover 30. In the main body frame 22, in addition to the link mechanism 1, the tool supporting means 2
8 and a work feeding means 29 are installed. The tool supporting means 28 has a plurality of punch tools 31 and die tools 32 mounted thereon, and is capable of indexing arbitrary tools 31, 32 (FIG. 11) at the press working position Q by the ram 6. The tool supporting means 28 are respectively the punch tools 3
Upper and lower turret 28 equipped with 1 and die tool 32
It consists of a and 28b. The work feeding means 29 causes the plate work W on the table 33 to be pressed at a pressing position Q at an arbitrary portion.
Is a means for moving in two orthogonal axes directions (X axis, Y axis). The work feeding means 29 is forward and backward (Y axis direction).
It has a moving carriage 34 and a cross slide 35 mounted on the carriage 34 and moving left and right (X-axis direction), and a plurality of work holders 36 provided on the cross slide 35 grip the plate material work W. Carriage 34
The plate work W is fed in the biaxial directions by the forward and backward movement of the cross slide 35 and the left and right movement of the cross slide 35.

The operation of the above configuration will be described. The specific configuration and operation of the ram shift mechanism 20 will be described later. 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 crankshaft 3 is rotated by driving the motor, the center of the eccentric shaft portion 4 of the crank member 2 draws a circular orbit C1 around the shaft center of the crankshaft 3, as shown in FIG. The oscillating link 5 includes the eccentric shaft portion 4
Since it is rotatably connected to the first connecting portion P1,
The orbital motion is performed along the circular orbit C1. Since the swing link 5 is linked to the restraint link 8 by the third linking portion P3, its operation is restricted.
A rotation motion is performed that swings in the forward and reverse directions around the first connecting portion P1. Due to the combined movement of the revolution movement and the rotation movement, the second portion which is the connecting portion of the swinging link 5 with the connecting rod 7
The connecting portion P2 moves along an oblique elliptical orbit C2 as shown in FIG. 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 swinging link 5 via the connecting rod 7, so that the second connecting portion P
2 moves up and down by drawing an elliptical orbit. The speed of the raising / lowering operation of the ram 6 is asymmetric between the descending time and the ascending time, as shown by the curve H in FIG. Also, ram 6 is at bottom dead center BDC
The crank angle θ _BDC at the time of reaching is at 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.

The 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 fulcrum position 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-the connecting portion P1-
It is necessary to establish a four-joint rotary chain that is established by using the fulcrum shaft 12 of the connecting portion P3-restraining link 8 as a connecting point between the joints, and the shortest joint is defined as the crank length r, and each of the following expressions must be satisfied. . 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.

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. 9 by comparing the crank type press and the link type press, when the cycle time is “10”, both the descending time and the ascending time are “5” in the crank type 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 is performed, as shown in FIG. 8, the punching section M, which is a section used for punching the plate 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 height relationship between each shift position of the ram shift mechanism 20 and the punch tool 31 on the tool supporting means 28 will be described with reference to FIGS. 13 and 14. The punch tools 31 (31 _{1 to} 31 ₈ ) at the respective positions supported by the upper turret 28a of the tool supporting means 28 are held at a constant height except for the punch tool 31 ₁ at the press working position Q. The height is maintained by engaging the neck portion of the punch tool 31 with a position-fixing guide ring (not shown) provided along the turret circumferential direction above the turret 28a, or each punch is held. This is performed by providing a supporting spring member (not shown) on the turret 28a for each tool 31. In the case of the above guide ring, it has a shape having a cutout portion at the press working position Q. The height of each punch tool 31 supported by the turret 28a as described above is, for example, such that the lower surface is substantially located on the lower surface of the turret 28a. In this embodiment, the ram 6 is of a type capable of engaging the neck portion of the punch tool 31 that has come to the press working position Q and forcibly pulling up the punch tool 31, and supporting the punch tool 31 at other positions. Is performed with the above guide ring. Engagement at the neck is achieved by inserting the punch tool 31 into the groove having a T-shaped cross section formed at the lower end of the ram 6.
The T-shaped head is fitted and the neck, which is the constricted portion of the T-shaped head, is hung.

When the punch tool 31 is driven up and down by the ram 6 at the press working position Q, as shown in FIG. 14B, the punch tool 3 located at the top dead center position of the lifting stroke.
1 is positioned below the other punch tools 31 on the turret 28a. When the top dead center position of the punch tool 31 at the press working position Q is lowered in this way, at the same height of the ram 6, the lower end of the ram 6 is lower than the upper ends of the other punch tools 31 of the turret 28a. Since it extends downward, when the turret 28a is rotated,
The other punch tool 31 interferes with the side surface of the ram 6, and the tool cannot be exchanged with the ram 6. Therefore,
The ram shift mechanism 20 switches the lower end position of the ram 6 between an upper shift position and a lower shift position. In this case, with the ram 6 in the link mechanism 1 at the top dead center position and the ram shift mechanism 20 in the upper shift position, as shown in FIG. 14A, the punch tool 31 and the turret 28a supported by the ram 6 are supported. The heights of the punch tools 31 above are the same. As a result, the tool can be smoothly replaced with respect to the ram 6 simply by rotating the turret 28a. Punching is performed by moving the ram 6 downward by the ram shift mechanism 20 as described above. Therefore, the top dead center in the lifting stroke of the punch tool 31 can be lowered, and the distance between the punch tool 31 and the surface of the plate material work W can be minimized. Therefore, the ram stroke is designed to be short and the punch tool 31
It is possible to shorten the descending time from the top dead center until it touches the surface of the plate material, and the time for the punch tool 31 to rise and retract,
The cycle time of work machining can be improved. As described above, the tool replacement work for the ram 6 can be easily performed while the punch tool 31 is configured to lower the top dead center to improve the cycle time.

Details of the ram shift mechanism 20 will be described with reference to FIGS. The ram shift mechanism 20 divides the connecting rod 7 into an upper rod 7a and a lower rod 7b that are elastically coupled to each other, and the upper and lower rods 7a,
Slider 52 (Fig. 12) can be inserted and removed between the ends of 7b.
Is interposed. In the slider 52, the thickness of the intervening portion between the upper and lower rods 7a and 7b differs depending on the insertion / removal position. In addition, the ram shift mechanism 20,
Even if the slider 52 is inserted and removed, the slider 52
An interlocking mechanism 53 is provided that moves the lower rod 7b up and down mechanically in conjunction with the inserting / removing operation of the slider 52 so that the upper and lower rods 7a and 7b come into contact with each other with no space therebetween.

In the divided portion of the connecting rod 7,
The upper part of the lower rod 7b is detachably connected to the lower part of the upper rod 7a. Specifically, the lower portion of the upper rod 7a is formed in a hollow shaft shape, and the upper portion of the lower rod 7b is fitted in the hollow hole so as to be slidable in the longitudinal direction.

The interlocking mechanism 53 is a cam mechanism including a guide plate 54 having a guide hole 55 and an action rod 56 slidably engaged with the guide hole 55 of the guide plate 54. Two guide plates 54 are provided on both side surfaces of the slider 52, and are fixed to the slider 52 at the front and rear ends. The guide plate 54 is provided with the guide hole 55 in a portion protruding downward from the slider 52. A pair of action rods 56 is provided on the upper end of the lower rod 7a so as to project in a direction orthogonal to the longitudinal direction thereof, and engages with the guide holes 55 of the guide plates 54 on both sides. An elongated hole 57 through which the working rod 56 of the lower rod 7b projects is formed in the lower portion of the upper rod 7a, which has a hollow shaft shape, along the longitudinal direction. The guide holes 55 of both guide plates 54 have a shape in which the front half is substantially horizontal and the rear half is inclined upward, and the guide holes 55 are integrated with the slider 52.
4 advances as shown in FIG. 12B, the lower rod 47b is pulled up by the guide of the guide hole 55. As a result, the connecting rod 7 is shortened.

The slider 52 is removably inserted into a lateral hole 64 formed in the upper rod 7a, and is driven forward and backward by a shift driving source 21 such as an air cylinder attached to the upper rod 7a. The lateral hole 64 is specifically formed along the upper bottom surface of the hollow shaft-shaped portion of the upper rod 47a. In addition, the lower end portion of the slider 52 facing the upper end 7bb of the lower rod 7b has an upper end 7 of the lower rod 7b.
A recess 52a for fitting into which bb is fitted is formed. In the fitting recess 52a, the slider 52 is moved to a predetermined insertion / removal position with respect to the upper rod 7a,
The upper end 7bb of the lower rod 7b can be fitted. Due to the formation of the fitting recess 52a, the thickness of the slider 52 varies depending on the insertion / removal position. That is, a portion of the slider 52 where the fitting recess 52a is formed is a thin portion, and a portion where it is not formed is a thick portion. The upper end 7bb of the lower rod 7b is formed as a boss protruding from the upper end surface of the lower rod 7b.

The ram shift mechanism 20 is used as a downward shift position when performing press working. Figure 1
In the ram shaft control means 61 for controlling the motor 13 for driving the crankshaft 3, the ram shift mechanism 20 operates the ram 6
The drive of the crankshaft 13 by the motor 13 is allowed in the state where is in the downward shift position. The ram shift mechanism 20 has a shift position detecting means 62 for detecting that the down shift position is reached. The shift position detecting means 62 may be provided in the shift drive source 21. The ram axis control means 61 is means for controlling the motor 13 in accordance with a ram drive command given from a machining program (not shown) or the like. For example, a numerical controller for controlling the entire motor driven link press (see FIG. (Not shown).

The operation of the ram shift mechanism 20 will be described. When it is set to the upper shift position, the connecting rod 7 is shortened as follows. That is, the shift drive source 21
The drive of the slider 52 causes the slider 52 to move from the normal position shown in FIG. 12 (A) to a predetermined position as shown in FIG. 12 (B). As a result, the recess 52a for fitting the slider 52 is formed.
Reaches the position where it crosses the inside of the upper rod 7a, and the guide hole 5 of the guide plate 54 that advances integrally with the slider 52.
5, the working rod 56 of the lower rod 47b is guided,
The lower rod 7b enters the fitting recess 52a such that the upper end 7bb of the lower rod 7b is in contact with the upper bottom surface of the fitting recess 52a of the slider 52 without a gap, and the connecting rod 7 is shortened. When the slider 52 is returned to the position shown in FIG. 9A by the driving of the shift driving source 21, the connecting rod 7 becomes the original length.

Since the ram shift mechanism 20 of this structure expands and contracts the connecting rod 7 as described above, it differs from the one that vertically shifts the entire link mechanism 1 including the crankshaft 3, the links 5, 8 and the like. A large mechanism is unnecessary, a large drive source is not required for the shift, and the ram shift mechanism 20 has a simple structure. Further, the expansion / contraction operation of the connecting rod 7 is performed by the interlocking mechanism 5 including the guide hole 55 and the working rod 56.
By the action of 3, the slider 52 is driven forward and backward, so there is no need to separately provide a drive source for expansion and contraction, and a simpler configuration is possible, and cost reduction can be achieved. Also,
It is not necessary to extend and contract the connecting rod 7 after waiting for the completion of the movement of the slider 52, and the operation time required for the expansion and contraction is shortened. When the ram 6 is to be driven by the motor 13 while the ram shift mechanism 20 is kept in the upper shift position, the function of the ram axis control means 61 prevents the drive and prevents a malfunction.

In the above embodiment, the ram shift mechanism 20 expands and contracts the connecting rod 7, but the ram shift mechanism 20 can switch the lower end position of the ram 6 between the upper shift position and the lower shift position. Any mechanism may be used, and for example, the entire link mechanism 1 may be vertically shifted. Further, in the above-described embodiment, the servo motor is used as the motor 13, but the servo motor may not necessarily be the servo motor. Further, the above embodiment has been described for the case of being applied to the punch press,
The motor-driven link press of the present invention can be applied to various press workings such as forming work and bending work in addition to punching work.

[0033]

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 so as to controllably move the ram up and down by controlling the rotation of the motor. Since a drive transmission system that does not include parts for the purpose of imparting inertia such as is used, controllability is also excellent. When a servomotor is used as the above-mentioned motor, various advantages can be achieved by free speed control while taking advantage of the link press. When this motor-driven link press is applied to a punch press, when the section used for punching the plate material work in the lifting stroke of the ram is an intermediate section of the descending process of the lifting stroke, A sufficient stroke can be obtained further downward, and the punched dust can be surely dropped.

[Brief description of drawings]

FIG. 1 is a cutaway front view of a link mechanism of a motor-driven link press according to an embodiment of the present invention.

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 partially omitted perspective view of the link mechanism.

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

FIG. 8 is a graph showing a relationship between a crank angle and a ram displacement in the link mechanism.

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

FIG. 10 is a plan view showing the entire motor-driven link press of the same embodiment.

FIG. 11 is a side view showing the entire motor-driven link press.

FIG. 12 is a cutaway side view showing a downward shift state and a downward shift position of a ram shift mechanism in the motor-driven link press.

FIG. 13 is a plan view of a turret in the motor-driven link press.

14 (A) and 14 (B) are sectional side views showing the positional relationship among the ram, the turret, and the punch tool at the upper shift position and the lower shift position in the motor-driven link press, respectively.

[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 axis 13 ... Motor 14 ... Drive transmission system 15 ... reducer 61 ... Ram axis control means 62 ... Shift position detecting 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. Rotatably connected at its tip to the third connecting portion of the swing link, and the ram lowering operation becomes slower than the ascending speed when the crankshaft is rotated in one direction at a constant speed. So on The drive transmission system is configured to transmit the rotational drive of the motor to the crankshaft so that the raising / lowering operation of the ram can be controlled by controlling the rotation of the motor. Motor driven link press. 2. The motor-driven link press according to claim 1, wherein the motor is a servomotor. 3. The motor-driven type according to claim 1, wherein in the punch press, a section used for punching a plate material work in an elevating stroke of the ram is an intermediate section of a descending process of the elevating stroke. Link press.