JPS645968B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a round bending method in a press brake for forming a workpiece into an arc shape with a certain radius of curvature, for example, a circular arc shape.

Conventionally, as a method of R-bending (R-bending) a workpiece, for example, processing it into an arc shape, by using a press brake, the workpiece is placed between a punch (upper mold) and a die (lower mold), which are processed into an arc shape. insert something,
Bend it once while pressing with a punch and die,
A method of processing that matches the arc shape of the punch,
The workpiece is inserted between a circular arc-shaped punch and a die with an elastic material such as urethane rubber on the top surface, and the workpiece is fed and bent by the desired amount for each bending process. I knew how to go.

However, in the case of the former processing method, it is necessary to manufacture punches and dies for each different arc shape of the workpiece, and both punches and dies are large and heavy, making it difficult to replace the dies. The problem was that it required a lot of time and effort.

In addition, in the case of the latter processing method, it is not possible to bend the arc radius smaller than that of the arc-shaped punch, so the punch must be replaced, and the punch and die must be adjusted for each feed rate of the workpiece. Since the approach distance is always constant, there is a problem that it becomes continuous and, for example, it is not possible to perform circular arc machining that is close to a perfect circle.

This invention effectively solves these conventional problems, and its purpose is to eliminate the need to change the punch and die even if the radius of curvature of the workpiece is changed. The present invention provides a processing method that can cleanly process the arc-shaped portions of.

In this invention, a workpiece is placed between a punch having a small arc at the tip and a die having a V-shaped mold groove, and in order to obtain the final bending angle of the workpiece,
For each diffraction bend, the workpiece is fed at the desired feed distance, and the approach distance between the punch tip and the bottom of the die (the state of engagement between the punch and die) is changed sequentially, and the workpiece is bent by air bending. By performing processing while moving forward, the final bending angle can be obtained by only one sequential bending movement from the rear to the front of the workpiece.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As for the bending method, in a press brake 1 as shown in FIGS. 1 to 3, a workpiece is placed horizontally on a die 7a having a V-shaped mold groove, and the die is bent by air bending. The workpiece is bent slightly (at an obtuse angle) by the punch 5a facing the punch 7a. In this case, since it is an air bend, the tip of the punch 5a and the bottom of the die 7a are measured based on the position where the tip of the punch 5a and the bottom of the die 7a abut.
The approach distance D ₁ (see FIG. 9a) from the bottom of the workpiece is controlled to perform the first bending of the workpiece.

Next, move the workpiece to the desired pitch P (see Figure 8).
(move the abutment (back gauge) 15 shown in Figures 2 and 3 forward by the pitch P) so that the bending angle of the bent corner becomes equal to the first bending angle. In this case, the workpiece is deformed by the first bending process and is not horizontal, so the punch 5a
The approach distance D ₂ between the tip of the die 7a and the bottom of the die 7a (9th
(see Figure b) is controlled again to bend the workpiece a second time.

Next, the workpiece is similarly moved by a desired bit P, and the approach distances D ₃ and D between the tip of the punch 5a and the bottom of the die 7a are adjusted so that the bending angles of the bent corners are the same every time. ₄ (see Fig. 9 c, d) respectively to bend the workpiece N times, and after passing through the states shown in Fig. 9 e and f, the radius is changed as shown by the imaginary line in Fig. 8. The workpiece can be bent at a bending angle A at R.

As described above, by moving the workpiece by the desired pitch P and continuously performing obtuse angle bending over the desired range of the workpiece, one part of the workpiece can be bent.
The part is bent into an arc shape. In this case, strictly speaking, the bending line is a continuous arc, so for example, when bending the workpiece into an arc, each pitch P
It is also desirable that the bending angles at each corner be equal. However, when the arc-shaped portion is not circular, the angles of each pitch P and each corner do not necessarily have to be equal, and may be set arbitrarily.

To explain in more detail the case of bending into an arc shape, FIG. 8 shows a processing state diagram when the workpiece W is bent into an arc shape with radius R and final bending angle A. is the number of bends N,
The shape of the m-th workpiece is shown.

Here, if the length of the arc is l, then l=f(A, R, K), The number of bends N is N=f(A,R).

The feed distance P for each time is P=l/N. Using this formula, if the bending angle A and bending radius R are set, and the number of bends is set, the feed distance P is
can be determined, and conversely, by setting the feed distance P, the number of bends N can be determined. (When setting the feed distance P, include limiting conditions so that the number of bends does not fall below the decimal point.) Also, even if the feed distance P and the number of bends N are not set, the number of bends N can be determined later. By setting the bending angle A and the bending radius R internally in the storage section of the control device, it is also possible to automatically calculate the feed distance P.

9a to 9f show the bending shapes of the workpiece W from the 1st to the Nth bending.
In Figure e), the m-th bending point is on the engagement line between the punch 5a and the die 7a.

In the case of arcuate bending, the shoulder in Fig. 11 is smaller than the actual shoulder of the V die (the engaging shoulder in the case of 90° bending).
Since the engagement point is at the point V ₁ , if the shoulder radius of the V die is Rd and the angle of the groove of the V die is θ, then V ₁ =f(V, Rd, θ).

Therefore, the feed distance P and the distance Cm required for bending the workpiece to the final bending angle A and the m-th bending number N are determined. The angles αm and βm in FIG. 8 are given by the following equations.

αm = f (A, m, N), βm = f (A, m, N) Number of bends N = distance between the engagement point of the first punch and die and the shoulder engagement point of the V die is b (9th (See figure a)
Then, b=f(V ₁ , A, N).

Further, the angles γm and θm in FIG. 8 are given by the following equations.

γm=f(b, p, bm, V ₁ , αm) From θm=180−γm−αm, the m-th distance Cm is Cm=f(V ₁ , θm) The number of bends N=1, that is, the first If the distance between the punch and die is D ₁ (see FIG. 9) and spring back is taken into account, then D ₁ =f(A, N, V ₁ , σ, B, T).

If the distance for the mth bend is Dm (see Figure 9e), it can be found as Dm=D ₁ -Cm+f(T, θm).

FIG. 10 shows a relationship diagram of the distance to the abutment (back gauge).

H ₁ = H ₃ + (b _N +1) + H _4Here , H ₄ = f (T, A, K ₂ ) If the distance from the first bending point to the end is L ₂ , then L ₂ = H ₃ + {P(N-1)-kTN} Here, kTN corresponds to the elongation of the workpiece.

L ₂ = H ₁ - (b _N +1) - f (T, A, K ₂ ) + P (N-1) - kTN Therefore, the m-th contact distance Lm is Lm = L ₂ - P (m-1) +kTN Length (developed length) of the workpiece shown in the figure before processing DP
is determined by DP=H ₁ +H ₂ -f(A, R, T) +P(N-1)-kTN.

As is clear from the above theoretical analysis, by setting the V-shaped die width V, plate thickness T, final bending angle A, bending radius R, etc. on the control panel 87 described later, the number of bends , or feed pitch P each time
This method automatically controls the approach distance between the punch and die and the distance to abutment when bending a workpiece.

Next, a press brake that can carry out the bending method according to the present invention will be described. FIGS. 1 to 3 show a front view, a side view, and a plan view of the press brake main body 1. The press brake main body 1 has a horizontally long upper apron 5 fixed above a frame 3 which is erected on the left and right, and is processed using a punch 5a and a die 7a while a lower apron 7 is raised and lowered by a hydraulic cylinder (not shown). belongs to.

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 (back gauges) 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. It is something.

The abutment 15 will be explained in more detail based on FIG. 4. The stretch 13 is connected to the guide 17 and the ball screw 11 attached to the left and right supports (not shown in FIG. 4). 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.

If the height of the die 7a attached to the lower apron 7 needs to be changed, rotate the handle 27 provided with the stretch 13 to move the stretch 13 up and down, and set the abutment 15 to the set height. move it to.

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 provided by 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.

A clutch 55 such as a spline is connected to the other end of the feed screw 49 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.

This 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 an M setting key 95 for setting auxiliary function parameters and correction amounts for the workpiece set above.
d, a work call key 95e for specifying the work number to be operated prior to continuous operation, and a position/speed display 9 for displaying the current positions and speeds of the L and D axes.
Set 5f and various parameters on the system
PA setting key 95g and PU start key 95 to start the puncher and punch out the necessary data onto paper tape.
h and a self-diagnosis key 95 that displays the alarm contents.
It is composed of i.

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. In this operation, as shown in FIG. 5 described above, when a working pressure fluid such as pressure oil is sent from the pump 83 to the cylinder 85, the lower apron 7 rises. In this case, when an excessive load is applied to the engagement between the punch 5a and the die 7a, damage such as buckling will occur in the upper apron 5 and the lower apron 7, so 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.

Next, the operating pressure fluid in the cylinder 85 is released, and the lower apron 7 is lowered.

From this state, input operations such as data settings and process settings are performed on the control panel 87 in order to perform the bending process into a predetermined shape.

This input operation uses the function key 95 and process data setting key 97 of the control panel 87 to input the plate thickness T of the workpiece W, the width V of the mold groove of the die 7a, and the circular arc of the workpiece W. Input the radius R and the final bending angle A of the workpiece W. (V angle θ of die 7a,
The shoulder radius Rd of the die 7a is determined by the width of the mold groove of the die 7a. In special cases, Rd and θ can also be input. ) Further, a fixed number of bends N is set in the control panel 87, and is calculated by calculating the feed distance P.

If particularly necessary, the feed distance P is calculated by setting the number of bends N. Furthermore, by setting the feed distance P, the number of bends N is calculated.

With the above settings and calculations, each bending content, for example, the distance of the punch 7a and die 5a at the m-th
Dm and the abutment distance Lm are determined, and the order in which the workpieces W are sequentially bent is also set by the control panel 87.

For the above settings, as shown in the block diagram of FIG. 7, there are a manual setting section 89 and a tape setting section 91 for tape input. puncher 9
You can also punch the tape with 7. and,
Based on the above settings, the NC calculation section 99
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.

Although the above example describes a press brake in which the lower apron 7 moves up and down, 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 above explanation, the present invention provides the following excellent effects.

(1) Smooth arc bending can be performed using a V-bending punch and die without requiring an arc-shaped punch and die.

(2) Since there is no need to change the punch and die according to changes in the arc radius of the workpiece, it is economical because the mold cost can be greatly reduced.

[Brief explanation of drawings]

Fig. 1 is a front view of the press brake main body, Fig. 2 is a side view of Fig. 1, Fig. 3 is a plan view of Fig. 1, Fig. 4 is an explanatory diagram showing the operating mechanism of the abutment part, Fig. 5
Fig. 6 is an explanatory diagram showing a control mechanism that controls the lifting and lowering operation of the lower apron, Fig. 6 is an explanatory diagram showing a setting board of the control panel, Fig. 7 is an explanatory diagram showing a control method by the control panel in a block diagram, FIG. 8 is an explanatory diagram when processing a workpiece to radius R and final bending angle A; FIGS. 9a to 9f are explanatory diagrams showing the arc bending process order of the workpiece; The figure is an explanatory diagram showing the relationship between the distances to the abutments, and FIG. 11 is an explanatory diagram of the engagement points in the case of arcuate bending. (Explanation of main symbols in the drawings) 5a...Punch, 7a...Die, W...Workpiece, 1...Press brake body.

Claims (1)

[Claims] 1 A part of the workpiece W is removed by a press brake,
A punch 5a and a die 7a provided in a press brake are used in a method of bending into an arc shape with a certain curvature.
The workpiece W is sent at a desired pitch P between the two, and the approach distance between the tip of the punch 5a and the bottom of the die 7a is controlled for each pitch to continuously bend the obtuse angle over a predetermined range. A round bending method using a press brake, characterized in that a part of a workpiece W is bent into an arc shape by bending the workpiece W into an arc shape.