JPH0120928B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a press brake, and more particularly to a press brake that detects the amount of displacement of a frame and has a bending angle feedback control function.

Conventionally, when using a press brake to perform a specified bending operation on a material, the material is inserted between a punch and a die, and the material is trial bent several times to adjust the engagement between the punch and die to achieve the required angle. I was adjusting the matching status.

For this reason, it takes a lot of time and effort to start the bending operation, and therefore the operation cannot be carried out efficiently.

Further, trial bending to a set angle often depends on the experience and feeling of the operator, making it difficult to perform accurate bending.

This invention effectively solves the above-mentioned conventional problems, and aims to improve the plate thickness, tensile strength, bending length, die groove width, and required bending of the workpiece. To provide a press brake that automatically controls the approach distance between a punch and a die by inputting an angle, etc., and enables efficient bending work without trial bending.

Hereinafter, a preferred embodiment of the present invention will be described based on the accompanying drawings.

1 to 3 show a front view, a side view, and a plan view of a press brake main body 1 embodying the present invention. A long upper apron 5 is fixed to the upper apron 5, and the lower apron 7 is raised and lowered by a hydraulic cylinder (not shown) while processing is performed using a punch 5a and a die 7a.

Support bodies 9 are fixed to the left and right sides of the lower apron 7, and a ball screw 11 provided on this support body 9 is fixed to the lower apron 7.
(See FIG. 4) The stretch 13 moves forward and backward by rotation. Also, on the front of the stretch 13,
A plurality of abutments 15 are provided so as to be movable in the left-right direction, and when setting the bending flange length of the workpiece, the workpiece is engaged with the abutments 15 to determine the dimensions. .

To explain the abutment 15 in more detail based on FIG. 4, the stretch 13 is attached to be movable back and forth via a guide 17 and a ball screw 11 attached to the left and right supports. , the ball screw 11 is rotated by a motor 19 fixed to the frame 3 via a spline shaft 21 and a gear 23.

Further, the amount of rotation of the ball screw 11, that is, the moving distance of the abutment, is detected by an encoder 25 attached to the rear end of the ball screw 11, and the rotation of the motor 19 is controlled.

In addition, when the height of the die 7a attached to the lower apron 7 is changed, the stretcher 13 is moved vertically by rotating the handle 27 provided on the stretcher 13, and the abutment 15 is adjusted to the set height. Move it up to the top.

Next, FIG. 5 shows a control mechanism for controlling the raising and lowering operation of the lower apron 7, and this control mechanism consists of a locking piece 2 provided at the longitudinal center of the lower apron 7.
A lever 31 which can be freely engaged and detached from the lower apron 7 is rotatably mounted on a rotating body 35 and a shaft 33 via a shaft 37 fixed to a frame (not shown) provided on the back side of the lower apron 7.

In addition, a lower apron 7 is attached to the frame (not shown).
An upper limit valve 39 is fixed, and a spool 41 of the upper limit valve 39 is engaged with one end of the lever 31 via a leaf spring 43 fixed to a frame (not shown).

The rotating body 35 is connected to one end of a feed screw 49 via a pin 45 and a lever 47, and the feed screw 49 is rotatably supported by a case 51 fixed to the frame 3.

The other end of the feed screw 49 is connected to a clutch 55 that is spline engaged via a gear 53, and a lever 57 is connected to the connecting portion of the clutch 55.
A manual handle 59 is connected thereto. The lever 57 is used to switch the clutch 55, and controls the rotation of the manual handle 59 from the feed screw 49.
5, the lever 57 is pushed to the right in FIG. 5, the clutch 55 is moved to the right, and the rotation of the manual handle 59 is transmitted through spline engagement.

The gear 53 provided on the feed screw 49 includes:
An endless belt 61 is wound around a gear 65a fitted to a shaft 65 of a detector 63 such as an encoder rotatably supported by the case 51.

A belt 69 is mounted on the detector 63 via a gear 67, and this belt 69 connects to the shaft 7 of a clutch 71 rotatably supported on the case 51.
The gear 75 is integrally fixed to the gear 75. A shaft 79 of a motor 77 attached to the case 51 is connected to one end of the clutch 71, and a tachogenerator 81 is fixed to one end of the motor 77.

As described above, the manual handle 59 or the motor 7
7 rotates the feed screw 49, which rotates the rotating body 35 about the shaft 37 to control the engagement distance between the lever 31 and the locking piece 29, that is, the upward stroke of the lower apron 7.

When raising the lower apron 7, pump 8
When pressure oil is supplied from 3 to the cylinder 85, the lower apron 7 rises, and the locking piece 29 also rises together. When the lever 31 is engaged, the lever 31 rotates counterclockwise around the shaft 33, pushes down the spool 41 of the upper limit valve 39 against the leaf spring 43, and supplies pressure oil from the pump 83 to the cylinder 85. is released from the upper limit valve 39 to the tank T side, and the lower apron 7 stops rising.

In FIG. 1, 87 is a control panel for inputting the bending angle required for processing the workpiece and automatically controlling the approach distance between the punch 5a and the die 7a.

As shown in FIGS. 2 and 6, inside the frame 3, there is a detection plate 1 for detecting the displacement of the press brake body 1 during processing of the workpiece W.
21 are provided.

As shown in FIG. 7, the detection plate 121 is rotatably supported by a shaft 125 integrated with the locking plate 123 above the frame 3.
A rotating body 129 is provided below the detection plate 12 and is rotatable around a shaft 127 supported by the frame 3.
1 is provided so as to guide the movement in the vertical direction.

As shown in FIGS. 8 and 9, the detection plate 121 includes a detector 13 that can be adjusted vertically and rotationally.
1 is provided, and this detector 131 is attached so as to come into contact with a locking plate 130 protruding from the frame 3.

The control panel 87 mainly includes a power switch 89 and a mode selection switch 9, as shown in FIG.
1, a manual feed rate selection switch 93, a function key 95, and a process data setting key 97.

The function key 95 is for each process (1 operation)
a process data setting key 95a for setting parameters necessary to define the process, a process data display 95b for displaying the contents of the above data settings, and a process setting key 95c for setting the process execution order.
and M setting key 9 for setting auxiliary function parameters and correction amounts for the workpiece W set above.
5d, a work call key 95e for specifying the work number to be operated prior to continuous operation, the L axis, the D
Start the position and speed display 95f that displays the current position and speed of the axis, the PA setting key 95g that sets various parameters on the system, and the puncher.
PU activation key 9 that prints the necessary data on paper tape
Self-diagnosis key 9 that displays 5h and alarm details
5i.

Next, when bending the workpiece W by inputting predetermined data into the control panel 87 as described above, the punch 5a required for bending is inserted into the upper apron 5.
and attach the required V-shaped die 7a to the lower apron 7.

When bending a workpiece, it is first necessary to align the attached punch 5a and die 7a. That is, the center of the tip of the punch 5a and the mold groove of the die 7a must be on a vertical line.

Therefore, the punch 5a and the die 7a are brought close to each other without placing the workpiece W on the die 7a. This operation is performed by pump 8 to cylinder 85 in FIG.
When a working pressure fluid such as pressure oil is sent from 3, the lower apron 7 rises. In this case, if an excessive load is applied during the engagement between the punch 5a and the die 7a, damage such as buckling may occur on the upper apron 5 and the lower apron 7.
Therefore, it is necessary to control the raised position of the lower apron 7.

Therefore, in the case of engagement between the punch 5a and the die 7a,
Rotation of the manual handle 59 rotates the feed screw 49, rotates the rotating body 35, and moves the lever 31 upward. When the lever 31 moves upward, the locking piece 29 of the lower apron 7
Keep pressing 1. As a result, the lever 31 is pressed, which pushes the spool 41 of the upper limit valve 39 and releases the operating pressure fluid from the pump 83 into the tank T.

That is, by rotating the manual handle 59, the lower apron 7 is raised with a small pressure due to the action of the upper limit valve 39.

When the punch 5a and the die 7a engage in this manner, the stroke point of the lower apron 7 is set as the origin.

When setting the origin of the upward stroke of the lower apron 7, the punch 5a and the die 7a engage and apply pressure, which causes the frame 3 to be displaced upward, and this displacement position causes the lower apron 7 to move upward. be the stroke origin.

Next, the operating pressure fluid in the cylinder 85 is released and the lower apron 7 is lowered. The lever 31 is operated by the motor 77 and the detector 63 so as to control the upward stroke of the lower apron 7 based on the set contents.
The workpiece W is placed on the die 7a and bent. In this case, the actual pressing force B _F
is not detected, so first, the position of the theoretical value D ₁ ,
Or the lower apron 7 is stopped at the stroke position of D ₁ =V/2+T-0.1.

With this value, pressurizing force is generated, so frame 3
The upward displacement position is detected by the detector 131, and the lower apron 7 is controlled to rise so as to subtract the upward displacement position of the frame 3 from the theoretical value _D1 .

Actual pressing force due to upward displacement of frame 3
B _F is calculated, the correction value δ is determined, the stroke D of the lower apron 7 is determined, and the lower apron 7 is controlled so as to achieve this D value.

Furthermore, depending on the amount of displacement of the frame 3, the pressing force B _F
In addition to calculating , the displacement amount of the member that guides the elevation of the lower apron 7 or the upward displacement amount of the upper apron 5 can also be calculated using the pressing force B _F.

Furthermore, the pressure of the lower apron 7 is detected and the pressing force B _F
It is also possible to calculate

Further, the amount of displacement of the upper apron 5 can be detected using a strain measuring device or the like.

When bending a predetermined shape from such a state, first input operations such as data setting and process setting are performed on the control panel 87.

This input operation is performed using the function key 95 and process data setting key 97 of the control panel 87 shown in FIG. Required bending angle A,
Input the numerical value of the mold groove width V of the die (lower mold).

In addition, there are few types of Rp at the tip of the punch,
Also, since it is rarely changed, a certain value is set in advance.

In addition, the shoulder radius Rd of the die 7a and the die 7a
The V angle θ is determined by the width V of the mold groove of the die 7a. In special cases, Rd and θ can also be input. _K1 is an end face treatment coefficient, which is input especially when the end face of the workpiece W is in poor condition.

_K2 is a preset value depending on the machine used, and there is no need to reset it unless the machine is changed.

After completing the data settings as described above, press the process setting key 95c of the function key 95.
The order of sequential bending of the workpiece W is set. At the same time, the auxiliary function M is set.

The above settings include manual settings 89 and tape settings 91 by tape input, as shown in the block diagram of FIG. 97
You can also punch the tape with Based on the above-mentioned settings, the NC calculation section 99 performs calculations, and the motor 77 is controlled via the amplifier 103 while constantly receiving feedback from the detector 63.
Then, the stroke of the lower apron 7 and the position of the lever 31 are controlled by the motor 77 and the detector 63, and the workpiece W is placed on the die 7a and bent.

Further, the positioning of the abutment 15 is also controlled by the motor 19 and encoder 25.

Next, the process of bending the workpiece W is shown in FIGS.
If explained theoretically with reference to FIG. 14, the analysis will be as follows.

That is, the workpiece W is bent by the tip Rp of the punch 5a and the shoulder radius Rd of the die 7a.

As the punch 5a and the die 7a approach, the workpiece W is bent by the tip of the punch and the contact point of the shoulder radius of the die moves sequentially.

The inner bending radius of the workpiece W changes depending on various conditions, but the relationship is as follows: inner bending radius=V/Q. Q = (V, T, A, σ, K ₁ ) K ₁ is the end surface processing coefficient of the workpiece, V: die groove width, T: plate thickness of the workpiece, Rp: punch tip radius, Rd; Shoulder radius of the die, θ: V angle in the mold groove of the die, A: bending angle of the workpiece W.

Although the bending state of the workpiece is analyzed in FIG. 12, it is only necessary to find the approach distance between the punch and the die with respect to the bending angle A. In other words, the distance between the tip of the punch and the bottom of the mold groove of the die can be determined.

From Figure 12, Z ₁ + (I-V/Q) + J + K = V/2tan (90-θ/
2) I=V/Q・1/sinA/2...J=T/sinA/2...From Figure 13 K=V/2tan(90-θ/2)-M-N...R=(cosA+θ/ 4/cosA-θ/4-tan180-θ/
4) Rd... M=(1-sinA+θ/4/cosA-θ/4) Rd... From the formula, N=[V/2-(cosA+θ/4/cosA-θ/4-tan1
80-θ/4)Rd〕tan(90-A/2)..., substitute the formula ∴K=V/2tan(90-θ/2)-M-N=V/2tan(90
-θ/2) -(1-sinA+θ/4/cosA-θ/4)Rd-[V/2
-(cosA+θ/4/cosA-θ/4 -tan180-θ/4)×Rd]tan(90-A/2)...Z ₁ =V/2tan(90-θ/2)-(I-V/ Q)-J
Substitute the formula ,, into -K and get Z ₁ = [V/2-(cosA+θ/4/cosA-θ/4-tan1
80-θ/4)Rd] tan(90-A/2)+(1-sinA+θ/4/cosA-
θ/4) Rd - (V/Q+T)1/sinA/2+V/Q...The point of engagement between the punch tip and the V angle of the die groove is rounded, so the die angle θ intersects with the punch tip. It's not a point.

Therefore, to find the distance between the punch tip and the bottom of the die groove, find Q ₁ in Figure 12 and find D ₁ .

Q ₁ = (1/cos (90-θ/2)-1) Rp... ∴D ₁ = V/2 tan (90-θ/2)-Z ₁ -Q ₁ , so,
Substitute the formula D ₁ = V/2tan (90-θ/2)-V/Q+(V/
Q+T)1/sinA/2-(1-sinA+θ/4/cosA
-θ/4) Rd -[V/2-cosA+θ/4/cosA-θ/4-
tan(180−θ/4)Rd〕×tan180−A/2−(1/cos
(90-θ/2-1)Rp... This formula is the distance between the tip of the punch and the bottom of the die when bending the workpiece, but this formula can be replaced with other formulas. As will be described later, the formula changes depending on the shape of the die.

That is, it can be shown that D ₁ ={T, A, Rd, Rp, V(U)} .

However, the formula does not take into account the characteristics that occur when the workpiece is bent.

That is, it is necessary to add the following conditions.

Let δ ₂ be the correction value for the amount by which the punch tip digs into the workpiece.

The correction value for the amount of swell in the longitudinal direction due to the pressing force of the upper apron and the lower apron is set as δ ₃ .

As described above, δ ₄ is a correction value for the amount of elastic displacement of the workpiece. The value of δ ₄ is a correction value based on the difference between the angle when actually bent and the angle when the pressing force is removed after bending.

δ ₄ is the bending angle A, the plate thickness T, and the width of the die groove V
It can be expressed as a function of (U).

δ ₄ = {A, T, V (U), σ, Rp} Thus, the distance D between the tip of the punch and the bottom of the die groove, taking into account the characteristics that occur when bending the workpiece, is D = D ₁ -(δ ₂ + δ ₃ + δ ₄ ) = {V (U) ₂ T, A, Rd)} − [(BF, B, σ) + (BF, B, K ₂ ) + {A, T, V (U ), σ, Rp}. That is, D={V(U) ₂ T, A, Rd, Rp} - {BF, B, σ, Rp, AT, V(U), K ₂ } Figure 14 shows the punch tip for a U-shaped die. and the distance between the dies. In this case, there are various ways to set the origin of D (one method is to find the origin by engagement with the tip angle of the punch and the shoulder radius of the die, the other is to set the origin by using a V-shaped origin setting die at the bottom of the U-shaped die). → In any case, it is necessary to align the punch and die in the left and right direction at the same time in Figure 14.) Only the part corresponding to Z ₁ in the equation is shown.

Z ₂ =U/2+Rd(1-cosA/2)/tanA/2+Rd(
1-sinA/2) Z ₁ =Z ₂ -U/Q+T/sinA/2+U/Q=U/Q+U
/2+Rd(1-cosA/2/tanA/2+Rd(1-sinA
/2)=U/Q+T/sinA/2 That is, it can be expressed as Z ₁ =(U, T, A, Rd), which corresponds to the formula.

As is clear from the above theoretical analysis, the control panel 87 displays the V width used for the workpiece W, the V groove angle θ, the shoulder radius R, the plate thickness T, the bending length B, the tensile strength S, etc. By inputting the data necessary for bending and the desired bending angle A, the approach distance between the punch 5a and the die 7a can be automatically controlled.

In the above embodiment, a press brake in which the lower apron 7 moves up and down is explained, but it goes without saying that it can also be applied to a press brake in which the upper apron 5 moves up and down.

As can be understood from the description of the embodiments above, in this invention, the punch 5a and the die 7a
In a press brake that bends a plate-shaped workpiece W by engaging with A detector 131 detects the amount of displacement of the frame 3, the plate thickness T of the workpiece W, the bending angle A, and the shoulder radius of the die 7a.
A theoretical value D ₁ of the distance from the bottom of the die 7a to the tip of the punch 5a is calculated using Rd, the punch tip radius Rp, and the mold groove width V of the die 7a, and the detector is used when bending the workpiece W. The pressing force BF is calculated based on the detected value of 131, and this pressing force
BF, the bending length B of the workpiece W, the plate thickness T, the tensile strength σ, the bending angle A, and the mold groove width V of the die 7a are used to consider the mechanical properties in the press brake and the elastic properties of the workpiece. A calculation unit that calculates a correction value δ and calculates a distance D to be controlled from the bottom of the die 7a to the tip of the punch _5a using this correction value δ and the theoretical value D1; Since it is equipped with a feedback control section that feedback-controls the state of engagement between the punch 5a and the die 7a based on the distance D, it is easy to bend the workpiece to a set angle. . That is, according to the present invention, there is no need for trial bending as in the conventional method, and work efficiency is improved, and the amount of deformation of the frame is actually detected by the detector 131, and correction is performed by taking the detected value into consideration. Since the frame is bent, the actual amount of displacement of the frame is taken into account when performing the bending process, and the bending process can be performed with high precision.

Note that this invention is not limited to the above embodiments,
Other embodiments are possible, and the numbers appended to the claims do not limit the technical scope.

[Brief explanation of drawings]

Fig. 1 is a front view of the press brake main body in which the present invention is implemented, Fig. 2 is a side view of Fig. 1, Fig. 3 is a plan view of Fig. 1, and Fig. 4 shows the operating mechanism of the abutment part. 5 is an explanatory diagram showing the control mechanism that controls the raising and lowering of the lower apron, FIG. 6 is a side view of the detection plate attached to the side of the press brake body, and FIG. 7 is the arrow shown in FIG. 6. Enlarged side view, Figures 8 and 9 are front and side views of the detector that detects the displacement of the detection plate, Figure 10 is an explanatory diagram showing the setting board of the control panel, and Figure 11 is the control panel. FIGS. 12 to 14 are explanatory diagrams showing the control method using a board in the form of block diagrams, and are explanatory diagrams for explaining the theoretical analysis of the process of bending a workpiece.
FIG. 3 is a processing explanatory diagram analyzing the bending state of the workpiece, and FIG. 14 is an explanatory diagram for setting the distance between the punch tip and the die in the case of a shaped die. Explanation of main symbols in the drawings, 5a...Punch, 7
a...Die, W...Workpiece, 1...Press brake body, 87...Control panel.

Claims (1)

[Claims] 1 In a press brake that engages a punch 5a and a die 7a to bend a plate-shaped workpiece W, a detection plate 121 suspended from the upper part of the frame 3 of the press brake and a detection plate 121 located above and below the detection plate 121 A detector 131 detects the displacement of the frame 3 by detecting the displacement of the frame 3, the plate thickness T of the workpiece W, the bending angle A, the shoulder radius Rd of the die 7a, the punch tip radius Rp, and the type of the die 7a. Die 7a due to groove width V
Theoretical value of the distance from the bottom of the hole to the tip of the punch 5a
D ₁ is calculated, and the pressing force is calculated based on the detected value of the detector 131 during the bending process of the workpiece W.
Calculate BF, and calculate the mechanical properties and damage in the press brake using the pressing force BF, the bending length B of the workpiece W, the plate thickness T, the tensile strength σ ₁ , the bending angle A, and the mold groove width V of the die 7a. A correction value δ that takes into account the elastic properties of the workpiece is calculated, and the punch 5 is moved from the bottom of the die 7a using this correction value δ and the theoretical value _D1 .
a calculation unit that calculates the distance D to be controlled to the tip of the punch a, and a feedback control unit that performs feedback control on the engagement state between the punch 5a and the die 7a based on the distance D calculated in the calculation unit. A press brake characterized by the following features: