JPH1147863A - Method for straightening deformed cross sectional bar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the straightening continuously to a deformed cross sectional bar without generating local deformation by arranging caterpillar type drawer devices in a linear state at interval and inserting and passing the deformed cross sectional bar into and through each drawer device and also, providing the speed differenel for a feeding speed of each drawer device. SOLUTION: The deformed cross sectional bar 4 is fed into two or more sets of the caterpillar type drawer devices (drawer device) 2a, 2b from a feeding- out machine 1. The deformed cross sectional bar 4 is pressed with caterpillar belts 9c of the caterpillars 5 in the drawer devices 2a, 2b and fed while holding between rolling reduction devices 6. The feeding speed of the drawer device 2b is faster than the feeding speed of the drawer device 2a and the deformed cross sectional bar 4 is stretched by the difference between both feeding speeds. The stretching force of the deformed cross sectional bar 4 is measured with a load cell 7 arranged at the lower part of the drawer device 2a to control the stretching force. Gap between the caterpillars 5 is the almost same thickness of a thin sheet part in the deformed cross sectional bar 4. Gap between the rolling reduction devices 6 is the almost same thickness of the projecting part of the deformed cross sectional bar 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for correcting a deformed cross section, and more particularly to a method for correcting a deformed cross section used as a lead frame material for a power transistor.

[0002]

2. Description of the Related Art In a strip material used for a lead frame material for a semiconductor, a straightening process is often included in a manufacturing process in order to improve a shape and make internal stress uniform.

As a general method of straightening a strip, as shown in FIG. 3, a clamp 11 provided at a predetermined interval is provided.
There is a method in which the strip 14 is clamped by a and 11b and pulled in the longitudinal direction of the strip 14 (the left-right direction in the drawing). When straightening the continuous strip 14 by this method, the strip 1
After being pulled in the longitudinal direction of No. 4, the strip 14 is fed in a fixed amount in one direction, and then clamped again and repeated.

[0004] Further, as shown in FIG.
Are arranged in a zigzag pattern, the strip 14 is inserted between the small-diameter rolls 12, and the strip 14 is repeatedly bent to perform correction. As shown in FIG. There is a method in which the strip material 14 is meandered around the bridging roll 13 and wound, and the straightening is performed by applying tension to the strip material 14, or a method in which both are combined.

FIG. 2 shows a cross-sectional view of the irregularly shaped cross section. FIG.
2A is a cross-sectional view of the deformed cross-section before the correction is performed, and FIG. 2B is a cross-sectional view of the deformed cross-section having a local warp caused by the correction.

[0006] As a strip material, a convex portion 4 as shown in FIG.
a and the deformed cross-section 4 having the thin plate portions 4b, 4b. When the deformed cross-section is corrected by the method shown in FIGS. 4 and 5, the convex portion 4a and the thin plate portion 4b, 4b
Since a bending stress is applied to the irregularly shaped cross-section strips 4 having different curvatures, deformation occurs such that the thin plate portions 4b, 4b warp to the convex portion 4a side as shown in FIG. 2B.

For this reason, as a method of correcting the irregularly shaped cross section strip 4, a method of intermittently applying a linear tension as shown in FIG. 2 is often used.

[0008]

However, in the method of intermittently performing the linear tension, it is necessary to alternately repeat the tension and the feeding of the irregularly shaped cross-section strip 4, which causes a problem that the processing efficiency is low. .

In order to improve the processing efficiency, it is conceivable to increase the distance between the clamps holding the deformed cross-section strip 4, but the deformed cross-section strip 4 before the correction shown in FIG.
If there is no distortion in the width direction (horizontal direction in the figure), it is good, but if there is distortion in the width direction (not shown), the portion clamped by the clamp is shown in FIG. Such local warping occurs. In the step subsequent to the step of correcting the irregularly shaped cross-section strip 4, press working or the like is performed, and this local warping hinders press working or the like.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a method for correcting a deformed cross-section strip that is continuous and free from local deformation.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a method for correcting a deformed strip having a convex cross-sectional shape, comprising at least two or more endless track belt type drawing devices. Are provided in a straight line with an interval, and the continuous deformed cross-section strip is inserted into each drawing device, and a pulling force for correction is given by giving a speed difference to the feeding speed of each drawing device. is there.

According to a second aspect of the present invention, the hardness of the endless track strip on the side of the convex section of the deformed cross section of each of the drawing devices is softer than that of the endless track strip on the side of the flat section of the deformed cross section. This is a method for correcting irregularly shaped cross sections.

According to a third aspect of the present invention, there is provided the method for correcting a deformed cross section according to claim 1, wherein a feed speed of the drawing device is higher at a downstream side in a traveling direction of the deformed cross section.

According to the above configuration, in the method for correcting a deformed cross section having a convex cross section, at least two or more endless track belt type drawing devices are linearly provided at intervals.
In order to apply the tensile force for straightening by inserting the above-mentioned irregular cross section continuous to each drawing device and giving a speed difference to the feeding speed of each drawing device, continuous and local deformation It is a method for correcting irregular shaped strips.

[0015]

Embodiments of the present invention will be described below.

FIG. 1 is a schematic view of a straightening device for straightening a deformed cross-section strip according to the present invention.

As shown in FIG. 1, a straightening device 10 includes a feeder 1 for supplying a deformed cross-section strip 4, a winding machine 3 for winding the deformed cross-section strip 4, and a tension corrector 10. It comprises at least two or more (two in the figure) endless orbital belt (commonly called caterpillar) type drawer 2.

As shown in FIG. 2A, the irregularly shaped section 4 has a convex portion 4a and thin plate portions 4b, 4b.

At least two or more endless track type drawers 2 (2a and 2b in the figure) are provided linearly with an interval therebetween.
An endless track strip 9c is stretched between the drums 9a and 9b, and is disposed between the upper and lower endless track strips 5 arranged vertically in parallel with each other and the endless track strips 5 and 5 of each step. And a pair of pressure reduction devices 6 and 6. Roll-down device 6
Is a roll head 6a provided with a plurality (six in the figure) of small-diameter rolls 6b.

Here, the gap between the endless orbit belts 5 of each stage is
The thickness is about the thickness of the thin plate portion 4b of the irregularly shaped cross section 4, and
The gap between the pair of pressing devices 6 and 6 is about the thickness of the convex portion 4a of the irregularly shaped strip 4. In addition, the endless orbit belt 5,
5 are connected by a shaft (not shown). The drum 9b (or 9a) of the upper endless track belt 5 and the drum 9b (or 9a) of the lower endless track band 5 are connected to each other. The gears and the like (not shown) rotate in the opposite direction at the same rotation speed.

The endless track type drawer 2b on the downstream side in the traveling direction (pass line direction) of the deformed section strip 4 is fixed on the base 8 on the base 8 fixed to the foundation (ground), and the left end thereof is fixed to the base 8. , And is slidably supported in the pass line direction via a load cell 7 for monitoring the pulling force in the pass line direction. Endless track type drawer 2
By supporting b on the base 2 so as to be slidable in the pass line direction, a tensile load is applied to the load cell 7 and, consequently, the tensile force can be controlled. In addition, load cell 7
The right end may be fixed to the base 8 in order to monitor the compression force in the pass line direction.

The space between the endless track type drawers 2a and 2b does not need to be large, and may be as short as possible without inconvenience in maintenance.

The crawler belt material 9c is not particularly limited, and may be, for example, a rubber belt or a block-shaped member joined in a rosary.

The material of the crawler belt material 9c is not particularly limited. For example, when a rubber belt is used as the crawler belt material 9c, if the rubber used is too soft, the rubber is deformed by crimping, and the irregular cross section is formed. Thin plate part 4 of Article 4
Since local warpage occurs in b and 4b, it is desirable to use hard rubber as much as possible, and it is particularly desirable that the hardness of the endless track strip 9c of each of the endless track strips 5 in the upper stage (on the side of the convex section with irregular cross section) be reduced. It is preferable that the endless track strip 9c of each of the endless track strips 5 at the lower level (on the side of the irregularly shaped cross section plane) is softer than the hardness thereof.

Next, the method for correcting a deformed cross-section strip according to the present invention will be described.

First, the deformed cross-section strip 4 supplied from the feeder 1 is inserted into the endless track type drawer 2a.

The thin plate portions 4b, 4b of the modified cross-section strip 4 inserted into the endless track type drawer 2a are inserted between the drums 9a, 9a of the opposing endless track bands 5, and each endless track band. It is pressed by the material 9c.

Next, the deformed cross-section strip 4 which has been press-bonded is held in a state in which the convex portions 4a of the deformed cross-section strip 4 are held between the opposing pressing-down devices 6, and the drums 9b of the opposing endless track belts 5 are held. ,
9c, and is pressed again by each endless track strip 9c.

The pressing force at this time varies depending on the cross-sectional area of the irregularly shaped strip 4, the width of the convex portion 4a, the material of the endless track strip 9c, and the like.

Thereafter, the deformed cross-section strip 4 inserted through the endless track type drawer 2a is inserted into the endless track type drawer 2b, and is crimped in the same manner as the endless track type drawer 2a. .

Here, the endless track type drawer 2a, 2b
There is a difference between the respective feed speeds in, and the feed speed of the crawler belt type drawing device 2b is higher. Assuming that the feed speed of the endless track type drawer 2a is Va and the feed speed of the endless track type drawer 2b is Vb, the irregularly shaped section 4
Is pulled at a speed of Vb-Va downstream in the pass line direction between the endless track type drawers 2a and 2b, and as a reaction force, a speed of Vb-Va upstream in the pass line direction. Will be pulled. That is, the tension at the speed of Vb-Va in the longitudinal direction of the deformed cross-section line 4 is defined as a tensile force for correcting the deformed cross-section line 4.

After that, the irregularly shaped cross section strip 4 inserted through the endless track type drawer 2b is wound up by the winder 3.

The pressing force F is given by the formula: sectional area of deformed cross section × tensile force per unit area / (coefficient of friction × 2). For example, if a rubber belt is used as the endless track strip 9c, The friction coefficient between the deformed cross-section strips 4 is 0.
When the cross section of the deformed section 4 is corrected to 50 mm ² and the tensile force per unit area is set to 30 kgf / mm ² , the pressing force F becomes about 1,500 kg.
f.

That is, the pressing force F is determined by three parameters: the cross-sectional area of the deformed cross-section strip 4, the tensile force per unit area, and the friction coefficient.

If the material of the modified cross-section strip 4 is changed, the surface quality of the modified cross-section strip 4 may be affected depending on the material of the endless track strip 9c. It is conceivable that paper, flannel, or the like is interposed between the tape and the article 4. In this case, the endless track strip 9
Since the coefficient of friction between c and the deformed cross-section strip 4 becomes smaller, a larger pressing force F is required.

The pulling force per unit area depends on the pulling force in the pass line direction of the irregularly shaped cross section 4 between the endless track type drawing devices 2a and 2b. Here, the load cell 7 provided below the crawler belt type drawer 2b measures the pulling speed in the pass line direction of the irregularly shaped strip 4 between the crawler belt type drawers 2a and 2b. From this measured value, the tensile force at the time of correction is calculated.

From the above, the endless track type drawing device 2
The tensile force can be increased or decreased by appropriately controlling the respective feed speeds a and 2b. Also,
Conversely, by increasing the feed speed of each of the endless track type drawers 2a and 2b while keeping the tension force at the time of correction using the load cell 7 constant, continuous correction at a constant tension force is always performed at a higher speed. Can be done.

Further, in the endless track belt type drawers 2a and 2b, the hardness of the endless track strip 9c of each of the upper endless track strips 5 is determined based on the hardness of the endless track strip 9c of each of the lower trackless track strips 5. Also, by softening and crimping, the deformation of the endless track strip 9c of each of the upper endless track strips 5 is increased, and the deformation of the endless track strip 9c of each of the lower endless track strips 5 is increased. Local warping of the thin plate portions 4b, 4b of the cross-sectional strip 4 can be further prevented. by this,
Workability in press working or the like, which is the next process of the straightening process, is improved.

FIG. 1 shows two endless track type drawing devices 2.
Although the deformed section 4 is corrected using a and 2b, when the cross section of the section 4 is large, it is necessary to obtain a larger tensile force and to increase the pressing force.

Here, when the correction is performed by using two endless track belt type drawing devices, it is necessary to increase the length of the endless track belt per vehicle, which causes a problem in terms of maintenance, The surface pressure of the raceway belt and the deformed cross-section strip increases, and the endless track strip may be deformed to cause local warping of the thin plate portion of the deformed cross-section strip.

Therefore, by using three or more endless track type drawing devices, it is possible to reduce the crimping force per one endless track type drawing device.
Since the length per unit is also shortened, the endless track belt can be driven at a higher speed, and the correction can be performed at a higher speed than when the correction is performed using two endless track type drawing devices.

[0042]

In summary, according to the present invention, the following excellent effects are exhibited.

(1) Since the deformed section is corrected by using at least two or more endless track type drawing devices, the deformed section can be corrected continuously.

(2) Even a deformed section having a distortion in the width direction can be corrected, and a good deformed section without local deformation can be obtained by this correction.

[Brief description of the drawings]

FIG. 1 is a schematic view of a straightening device for straightening a deformed cross-section strip according to the present invention.

FIG. 2 is a cross-sectional view of a profiled strip.

FIG. 3 is a view showing a conventional method for correcting a strip material and a deformed cross-section strip.

FIG. 4 is a view showing a conventional method of straightening a strip.

FIG. 5 is a view showing a conventional method of straightening a strip.

[Explanation of symbols]

 2 Endless track type drawer (drawer) 4 Deformed cross section 4a Convex part 9a Endless track strip

Claims (3)

[Claims] 1. A method for correcting a deformed cross-section strip having a convex cross-sectional shape, wherein at least two or more endless track type drawing devices are linearly provided at intervals and connected to each drawing device. A method for correcting a deformed cross-section, wherein a deformed cross-section is inserted, and a pulling force for correction is imparted by giving a speed difference to a feed speed of each drawing device. 2. The straightening section according to claim 1, wherein a hardness of the endless track strip on the side of the convex section of the deformed section of each of the drawing devices is softer than that of the endless track strip on the side of the plane of the shaped section. Method. 3. The method for correcting a deformed cross section according to claim 1, wherein the feed speed of the drawing device is higher at a downstream side in the traveling direction of the deformed cross section.