JPH0780555A - Method for calculating spring back coefficient of roll bender - Google Patents

Abstract

PURPOSE:To provide a method which can easily calculate the spring back coefficient in bending a metallic plate by a roll bender consisting of an upper roll and two lower rolls. CONSTITUTION:In a roll bender which consists of an elevatable upper roll 10 and lower rolls 1 2, 14 and passes a metallic plate 16 between the upper roll and the lower rolls to provide the cylindrical bending, the elevating quantity of a rotary member 20 which can be elevated/lowered while being brought into contact with the metallic plate 16 elevating during the bending operation is detected, and the curvature in bending the metallic plate is calculated by this elevating quantity. The spring back coefficient specific to the metallic plate 16 is calculated from the calculated curvature in the bending of the metallic plate 16, and various control data in the roll bender are corrected according to this calculated spring back coefficient.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for calculating a springback coefficient of a roll bender, and more specifically, it bends a metal plate by a roll bender consisting of an upper roll and two lower rolls arranged diagonally left and right of the upper roll. When forming a cylindrical body with the required curvature, it is possible to easily calculate the springback coefficient required for controlling the roll bender and prevent the curvature difference due to springback that occurs in the bent cylindrical body. The present invention relates to a springback coefficient calculation method.

[0002]

2. Description of the Related Art As shown in FIGS. 9 and 10, a required length is provided between an upper roll 10 and two lower rolls 12 and 14 which are disposed diagonally below and to the left and right of the upper roll 10, respectively. 2. Description of the Related Art A roll bender is widely known in which a metal plate 16 having a length of 40 mm is passed through, and a cylindrical bending process is applied to the metal plate by the upper roll 10 and two lower rolls 12 and 14.
With regard to the basic structure of this roll bender, in order to efficiently bend a metal plate as an object to be processed with good accuracy, for example, as shown in Japanese Patent Publication No. 37-1570, the lower roll is placed in the horizontal direction. And a structure in which the upper roll is raised or lowered within a predetermined range along a vertical line passing through the central axis of the roll, as shown in Japanese Patent Publication No. 46-7451. What you have done is known.

[0003]

The following problems are pointed out when bending a metal plate into a cylindrical body by using a conventionally known roll bender. That is, the metal plate used for bending has elasticity peculiar to the material.
Therefore, even if the roll bender is used to forcibly bend the metal plate to form a cylinder with the required curvature, the curvature of the obtained cylinder does not fall within the range of the expected value, and is less than the desired curvature. There is the inconvenience of becoming large. This is because after the metal has been bent to a target value of curvature, the metal material bends slightly due to the elasticity inherent in the metal material, which is generally called "spring back". Therefore, when operating the roll bender,
A skilled worker previously passes a metal plate through the roll bender to perform trial bending, and finely adjusts the operation of the upper and lower roll groups according to the result. For example, the curvature of the metal plate set in the roll bender is set to be smaller than the originally required curvature, and the curvature of the cylindrical body in the state where the bending back is finished and the spring back is generated is the desired curvature. This is the operation to make it fit. However, this operation requires a skilled operator's experience and intuition, and also has the drawback of wasting material and time because trial bending is performed several times.

The springback coefficient peculiar to the material to be bent can be calculated by the following mathematical formula. Here, K is a springback coefficient. Also, r ₁
Is the desired inner diameter of curvature obtained by bending, and r ₂
Indicates the inner diameter of the curvature in the state where the springback after bending causes a slight return. S indicates the plate thickness of the material (metal plate) to be bent (see FIG. 8 for both). Therefore, the springback coefficient K is calculated and input to the computer control data in the roll bender. However, the desired inner radius of curvature “r ₁ ” and the inner radius of curvature after the return is “r ₂ ”,
Instantaneous calculation is extremely difficult. Therefore, it is necessary to measure the inner diameter of curvature of the bent cylindrical body each time and input data, and as a matter of fact, it takes a lot of time and labor as in the case of relying on an expert.

[0005]

It is an object of the present invention to bend a metal plate of a required length into a cylindrical body by a roll bender consisting of one upper roll described above and two lower rolls on the left and right arranged diagonally below the upper roll. At this time, it is an object of the present invention to provide a springback coefficient calculation method capable of preventing inconvenience such as occurrence of springback when the metal plate is bent, which may hinder the bending accuracy of the obtained cylinder. To do.

[0006]

[Means for Solving the Problems] In order to overcome the above problems and preferably achieve the intended purpose, the method of calculating the springback coefficient of a roll bender according to the present invention can move up and down along a perpendicular line passing through the central axis. And an upper roll provided on the lower side of the workpiece, and two lower rolls respectively disposed on the inlet side and the outlet side of the material to be processed with the perpendicular line interposed therebetween. The material to be processed is provided between the upper roll and the two lower rolls. In a roll bender that imparts a cylindrical bend to the metal plate by passing the metal plate, the amount of vertical movement of a rotating member that can move up and down while contacting the metal plate that moves up and down during the bending process is detected. , Calculating the curvature at the time of bending of the metal plate by this amount of elevation, from the curvature at the time of bending of the metal plate obtained from the calculation, to calculate the springback coefficient specific to the metal plate,
It is characterized in that various control data in the roll bender are corrected according to the calculated springback coefficient.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a method for calculating a springback coefficient of a roll bender according to the present invention will be described below with reference to the accompanying drawings with reference to preferred embodiments. The basic configuration of the roll bender is shown in FIG. That is, the upper roll 10 in the roll bender can be raised or lowered stepwise or continuously along the perpendicular line S ₀ passing through the central axis thereof. Further, the lower roll 12 (on the material-containing side) located diagonally on the right side of the perpendicular S ₀ of the upper roll 10 and the perpendicular S ₀
Lower roll 14 located on the diagonal left side across the material (material exit side)
Can be integrally displaced in the material feeding direction (+) or the counter feeding direction (-) with S ₀ as a reference.
Then, in the bending process of the metal plate 16, the upper roll 10 has a vertical line S.
_This is achieved by the operation of moving up and down along the ₀ at the required timing, and the operation of the lower rolls 12 and 14 integrally moving at the required timing in the feeding direction or the anti-feeding direction of the metal plate 16 with reference to the perpendicular S ₀ . However, the raising and lowering drive mechanism of the upper roll 10 and the displacement drive mechanism of the two lower rolls 12 and 14 are well-known structures and will not be described.

FIGS. 4 to 6 show an example of an apparatus capable of suitably implementing the spring bend coefficient calculation method for a roll bender according to the present invention. This springback coefficient calculator is used for the lower roll 12,
It is provided in relation to the measuring roll 20 which is arranged between 14 so as to be movable up and down. That is, in order to bend a metal plate with a roll bender, one upper roll 10 and two lower rolls 12 and 14 are rotated in a forward rotation direction or a reverse rotation direction at a required timing, and the metal plate 16 is rotated. It is important to control the material to move forward or backward in the material feeding direction (+) or counter feeding direction (-) by the required amount. In order to achieve this control with high precision, the metal plate 16 should have the material feeding direction (+).
Alternatively, it is necessary to accurately know the feed amount that can be moved forward / backward in the reverse feed direction (-). Therefore, the applicant of the present application proposes that the measuring roll 20 is vertically movable between the two lower rolls 12 and 14 as an auxiliary device for suitably performing the bending process of the metal plate. The details are disclosed in Japanese Patent Application No. 5-120789.

The springback coefficient calculating device shown in the embodiment is arranged as follows in relation to the measuring roll 20. For example, a small-diameter measuring roll 20 is rotatably supported via a pair of elevating frames 22 and 22 in a space formed between two parallel lower rolls 12 and 14 in a roll bender. That is, the measuring roll 20
Is fixed to a long rotary shaft 24 horizontally supported by a pair of lifting frames 22 and 22. Since the pair of lifting frames 22 and 22 have the same configuration on the left and right, only one lifting frame will be described. In particular, as shown in FIG. 6, the elevating frame 22 is fixed to the tops of the vertical guide shafts 26, 26, and these guide shafts 26, 26 are movably inserted and supported by the corresponding bases 28, 28. . The bases 28, 28 are the base frame 30 of the roll bender.
It is fixed to.

As shown in FIG. 4, the base frame 30 has a common shaft 3 directly below and parallel to the rotary shaft 24.
2 is rotatably supported by bearings 34, 34. The first pinion 36 and the second pinion 38 are fixed to one end of the common shaft 32, and only the first pinion 36 is fixed to the other end. Further, as shown in FIG. 6, a first rod-shaped member is provided inside the elevating frame 22.
A rack 42 is fixed vertically, and the first rack 42 meshes with the first pinion 36 of the common shaft 32. Further, a fluid pressure cylinder 39 is horizontally arranged on the side surface of the base frame 30 of the roll bender, and a rod-shaped second cylinder is provided at the tip of a piston rod 40 extending from the cylinder 39.
The rack 44 is fixed and extends horizontally. This second
The rack 44 meshes with the second pinion 38 of the common shaft 32. Therefore, when the fluid pressure cylinder 39 is driven forward and backward, the common shaft 32 rotates in the forward or reverse direction under the meshing action of the second rack 44 and the second pinion 38. Then, under the action of the first pinion 36 fixed to both ends of the common shaft 32 and the first rack 42, the pair of elevating frames 22 and the rotating shaft 24 equipped with the measuring roll 20 are integrated into a horizontal posture. Can be moved up and down while holding (see FIG. 1 and FIG. 2).

The fluid pressure cylinder 39 is always kept in a biased state when the roll bender is in operation, and the piston rod 40 thereof is extended from the cylinder barrel. Therefore, as shown in FIG. 1, the measuring roll 20 always rises to the maximum and is positioned slightly above the horizontal pass line PL through which the metal plate 16 passes. The common shaft 32 is connected with a lift amount measuring means 48 including a pulse generator or the like, and the lift frame 2 forming the pair is connected.
2, 22, in other words, a pulse can be generated according to the amount of elevation of the measuring roll 20. A ring made of hardened steel is externally fitted to the measuring roll 20, and the measuring roll 20 slips by contacting the lower surface of the metal plate 16 fed horizontally when the measuring roll 20 is maximally raised. Freely rotate without following. Since the rotation measuring means 46 composed of a pulse generator or the like is connected to one end of the rotating shaft 24, the feed amount of the metal plate 16 is changed by the follow-up rotation of the measuring roll 20 with respect to the metal plate 16. Can be detected by. As described above, the measuring roll 20 is brought into direct contact with the metal plate 16 and slippage is hardly generated in order to measure the feed amount, and thus the feed amount of the metal plate 16 can be accurately measured.

Next, the operation of the springback coefficient calculating device during bending according to the embodiment will be described below. When carrying out the arc bending of the metal plate 16 by the roll bender, first, as shown in FIG. 1, the upper roll 10 is positioned above the pass line PL, and the metal plate 16 is moved along the pass line PL. Feed it horizontally on top of 14.
At this time, the measuring roll 20 is in contact with the metal plate 16 in a pushed-up state from below. Then, as shown in FIG.
By forcibly lowering the upper roll 10 below the pass line PL and driving the upper and lower rolls in the material feeding direction, the metal plate 16 is bent.
As the metal plate 16 descends while being curved between the two lower rolls 12 and 14, the measuring roll 20 that is in contact with the lower roll 12 also descends synchronously, and the descending amount is the common axis. It is output as the number of pulses generated from the rotation pulse generating means 48 provided in 32.

After the metal plate 16 is bent in this way to form the cylindrical body shown in FIG. 2, when the upper roll 10 is raised, the upper roll 10 and the lower rolls 12, 14 are made.
The clamp to the metal plate 16 due to is released. When the upper roll 10 rises, the springback acts on the cylinder body that has just been bent. For this reason, as shown in FIG. 3, as a result of the curvature of the cylindrical body (metal plate 16) changing in the increasing direction, the metal plate 16 slightly rises by the amount of springback. That is, the measuring roll 20, which is in contact with the cylindrical body in a pushed-up state from below, also rises synchronously, and the amount of rise is output as the number of pulses generated from the rotation pulse generating means 48. The signal from the rotation pulse generating means 48 may be subjected to arithmetic processing in a control circuit (not shown) to obtain the curvature of the cylindrical body, which may be displayed in real time on a liquid crystal display or the like. At this time, the operator of the roll bender can grasp visually the curvature of the cylindrical body during bending, which is extremely convenient.

The ascending / descending amount of the measuring roll 20 can be calculated based on the number of pulses generated by the rotation pulse generating means 48. Therefore, when the metal plate 16 is bent, the winding inner radius (that is, the curvature) of the cylindrical body when the metal plate 16 is clamped by the upper roll 10 and the lower rolls 12 and 14 as shown in FIG. As shown in FIG. 3, the spring back coefficient is calculated by dividing the calculation into the case where the upper roll 10 is raised and the clamp on the metal plate 16 is released, and substituting these curvatures into the following mathematical formulas. Easy to find. K: springback coefficient, r ₁ : desired inner diameter of curvature obtained by bending, r ₂ : inner diameter of curvature with slight return due to springback after bending, S:
Thickness of material (metal plate) to be bent

Therefore, a calculation example in which the winding radius r of the cylindrical body when the metal plate 16 is bent is calculated from the amount of lowering of the measuring roll 20 will be described below.
FIG. 7 is a process drawing of bending the metal plate 16. In this figure, R: outer radius of winding, r: inner radius of winding, t: thickness of metal plate, a: lower roll radius (150),
b: measured value, c: half the pitch between the lower rolls (225),
y: Indicates the measured value (the amount of descent from the linear metal plate). Here, from (R + a) ² = (R + b) ² + c ² , R ² + 2Ra + a ² = R ² + 2Rb + b ² + c ² 2Ra-2Rb = b ² + c ² −a ² 2R (a−b) = b ² + c ² −a ² Here, when R = r + t and b = a−y are substituted, Therefore, The winding inner radius r corresponds to the desired inner radius of curvature r ₁ obtained by the bending process described above.

Calculation Example (1) The metal plate 16 has an actually measured value of y = 2.
When 0 mm down (t = 30),

Calculation Example (2) The metal plate 16 has an actually measured value of y = 5.
When 0 mm down (t = 30)

Once the inner winding radius r ₁ is obtained as described above, the inner winding radius r ₂ when the clamp on the metal plate 16 is released by raising the upper roll 10 shown in FIG. 3 is obtained by the same method. . The in-winding radius r ₂ indicates the inner diameter of the curvature in the state where the spring-back after the bending process causes a slight return. By substituting the desired inner radius of curvature r ₁ thus obtained, the inner radius of curvature r _{2 in} the state of springback, and the plate thickness S of the metal plate 16 into the following equation, the spring The back coefficient is calculated. Note that the calculation of these mathematical expressions is instantaneously executed by the computer incorporated in the control system of the roll bender. Then, the obtained springback coefficient is directly taken in to correct various control data in the roll bender.

[0019]

As described above, according to the method of calculating the springback coefficient of the roll bender according to the present invention,
When a metal plate having a required length is bent into a cylindrical body by a roll bender consisting of one upper roll and two left and right lower rolls arranged diagonally below the upper roll, when bending the metal plate It is possible to prevent inconveniences such as the occurrence of springback, which hinders the bending accuracy of the obtained cylindrical body. Therefore, the beneficial effect of obtaining the cylindrical body with excellent winding precision is achieved.

[Brief description of drawings]

FIG. 1 is a side view of an apparatus for implementing a springback coefficient calculation method according to the present invention.

FIG. 2 is a side view of an apparatus for implementing the springback coefficient calculation method according to the present invention.

FIG. 3 is a side view of an apparatus for implementing the springback coefficient calculation method according to the present invention.

FIG. 4 is a front view showing an example of an apparatus for carrying out the springback coefficient calculation method according to the present invention.

FIG. 5 is a side view showing an example of an apparatus for implementing the springback coefficient calculation method according to the present invention.

FIG. 6 is a perspective view showing an example of an apparatus for carrying out the springback coefficient calculation method according to the present invention.

FIG. 7 is a process drawing of bending a metal plate.

FIG. 8 is an explanatory diagram showing a desired inner diameter of curvature of a metal plate obtained by bending and an inner diameter of curvature of the metal plate in a state where a slight return is caused by springback after bending.

FIG. 9 is an explanatory view showing a step of a method of bending a cylindrical body according to a conventional technique.

FIG. 10 is an explanatory view showing a step of a method of bending a cylindrical body according to a conventional technique.

FIG. 11 is an explanatory diagram showing a step of a method of bending a cylindrical body according to a conventional technique.

[Explanation of symbols]

10 Upper Roll 12 Lower Roll 14 Lower Roll 16 Metal Plate 20 Rotating Member S ₀ Perpendicular

Claims (3)

[Claims] 1. An upper roll (10) arranged so as to be able to move up and down along a perpendicular (S ₀ ) passing through a central axis, and an upper roll (10) sandwiching this perpendicular (S ₀ ) on the inlet side and the outlet side of a material to be processed. Two lower rolls (1
2, 14) and by passing a metal plate (16) which is a material to be processed between the upper roll (10) and the two lower rolls (12, 14), the metal plate (16) is In a roll bender that imparts a cylindrical bend, the amount of lifting of a rotating member (20) that can move up and down by contacting the metal plate (16) that moves up and down with the bending is detected, and the metal plate is detected by this amount of lifting. The curvature during bending of (16) was calculated, and the springback coefficient specific to the metal plate (16) was calculated from the calculated curvature during bending of the metal plate (16). A method for calculating a springback coefficient of a roll bender, wherein various control data of the roll bender is corrected according to a springback coefficient. 2. The two lower rolls (12, 14) have a material feeding direction (+) or a counter feeding direction with respect to the perpendicular (S ₀ ).
The method for calculating the springback coefficient of a roll bender according to claim 1, wherein the springback coefficient is integrally displaceable to (-). 3. The rotating member (20) comprises two lower rolls (12,
14) A metal plate that is placed between the two and is movable up and down
Rotation measuring means that can detect the feed amount of (16) by the number of pulses
The method for calculating a springback coefficient of a roll bender according to claim 1, which is a measuring roll having (46).