JPH10125513A - Device for manufacturing current detecting resistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for manufacturing a current detecting resistor which manufactures the current detecting resistor of high reliability, extremely low resistance and high precision with low cost. SOLUTION: This manufacturing device is provided with a device 5 for manufacturing a resistor which welds lead terminals to about both ends of a strip of metal resistance material to manufacture a resistor, a forming machine 6 which works the manufactured resistor by bending, a resistance value detecting/measuring device 7 which measures a resistance value to judge normal or defective and further outputs deviation value information from the pre-set resistance value, and a control device 8 which inputs the deviation value information and controls the device 5 so as to modify the welding point of the lead terminal in the resistance material to bring the deviation to a value close to 0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current detecting resistor mounted on a printed circuit board, for example.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 7, a current detecting resistor of this type is provided with lead terminals 2 near both ends of a strip-shaped metal resistor 1 cut to a predetermined size from a band-shaped hoop material.
Are welded (3 is a welded portion), and are bent and shaped so that the lead terminals 2 face in the same direction, and are mainly used by being mounted on a printed circuit board.

[0003] The resistance value is in the range of several mΩ to several tens mΩ, and high accuracy such as 5 mΩ ± 1% is required. Now, as shown in FIG. 8, the total length of the resistor 1 is L, the width is b, the thickness is t, and the welding portion 3 of the lead terminal 2 is
Is an interval of l, the resistance value R is R = specific resistance × (l / b
-It is represented by t).

[0004] The current detecting resistor manufactured in this manner has a stable resistance value, is highly reliable, and can flow a large current. Therefore, it is used as an element for detecting a current value flowing in a circuit. .

[0005]

Generally, a resistor obtained by rolling a resistance material to a predetermined thickness and cutting it to a predetermined width must allow a variation of ± 5% or more.
It is not easy to manufacture a resistor of ± 1% from a material with a variation of ± 5%, so it is necessary to select a resistor that meets the specifications from the manufactured resistors. As a result, the yield is low and the cost is high.

Therefore, when the material (resistivity), width b and thickness t of the resistor are selected, the total length L is determined in order to obtain a predetermined resistance value.
Is determined, and fine adjustment of the resistance value is performed by changing l. Although this is theoretically clear,
It is not easy in actual production. That is, for example, 5m
Conventionally, it has been difficult to manufacture a current detecting resistor having a high accuracy of Ω ± 1% on a commercial basis.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a highly reliable, extremely low-resistance, high-precision current detecting resistor at low cost. An object is to provide a manufacturing apparatus.

[0008]

In order to achieve the above object, a current detecting resistor manufacturing apparatus according to the present invention comprises a system in which lead terminals are welded to both ends of a strip-shaped resistor near both ends thereof. A resistor manufacturing apparatus for manufacturing a resistor, a resistance value measuring device for measuring the resistance value of the manufactured resistor and judging pass / fail, and outputting deviation value information from a preset resistance value, and a deviation value A control device is provided for controlling the resistor manufacturing apparatus so as to input information and finely adjust the welding location of the lead terminal of the resistor to make the deviation value close to zero. In addition, you may further arrange the shaping machine which bends the resistor taken out from the resistor manufacturing apparatus.

Even if the hoop-shaped resistor has a variation of ± 5%, the variation generally gradually changes from one part of the hoop material to another part. Therefore, it is relatively homogeneous in part. Therefore, according to the above configuration, the resistance value measuring device measures the resistance value of the resistor manufactured by the resistor manufacturing device and feeds back the deviation value information at that time to the control device, and the control device sets the deviation value to 0. The resistor manufacturing apparatus is controlled so as to correct the welding portion of the lead terminal of the resistor so as to approach the temperature. The resistor manufacturing apparatus corrects the welding location and performs the welding of the lead terminal according to the instruction of the control device, so that the resistance value of the subsequent resistors is within the allowable range.

[0010] Further, the resistor manufacturing apparatus includes a work transfer unit for chucking a resistor cut to a predetermined size from a hoop material and transferring the same to a welding position, and a pair of lead terminals for cutting and supplying a lead terminal of a predetermined size from a continuous electric wire. A lead terminal supply unit and a pair of lead terminal transfer units for nipping the supplied lead terminals and transferring them to a welding position, and aligning one end of the lead terminals with the welding location of the resistor transferred to the work transfer unit. The pair of welding units to be welded and the frame on which the welding unit and the lead terminal transfer unit are mounted are sandwiched by the upper and lower welding electrodes, respectively. And a pair of frame displacing means.

According to this structure, the frame displacing means displaces the welding unit and the lead terminal transfer unit to the optimum welding position in accordance with the instruction of the control device, and the work transfer unit places the lead terminal on the transferred resistive element. Welding is performed at the corrected welding spot interval.

[0012]

Embodiments of the present invention will be described below in detail. (Embodiment 1) First, FIG. 1 shows a system of an apparatus for manufacturing a current detection resistor according to Embodiment 1 of the present invention. The product to be manufactured is made by welding the lead terminal 2 to the resistor 1 as shown in FIGS.

Reference numeral 5 denotes a metal resistor 1 cut into a strip shape.
Lead terminals 2 are welded near both ends of a resistor (hereinafter simply referred to as a resistor), and a resistor is manufactured from the outside by a resistor manufacturing apparatus for manufacturing a resistor as shown in FIG. Reference numeral 6 denotes a shaping machine for bending a resistor taken out of the resistor manufacturing apparatus 5 so that the lead terminals 2 face in the same direction as shown in FIG. 7, and 7 measures a resistance value of the shaped resistor. Then, it is detected whether or not it is within a preset allowable error range, for example, the target resistance value ± 1%. Even if there is a certain range set in advance, for example ± 0.
If it exceeds 5%, the resistance value detector 8 outputs deviation value information from the target resistance value. The resistance value detector 8 inputs the deviation value information, and sets the lead terminals of the resistor in order to make the deviation value close to zero. This is a control device that controls the resistor manufacturing device 5 so as to correct the welding location.

It is to be noted that supply of materials to the resistor manufacturing apparatus 5
The worker may manually transfer and deliver the resistor between the resistor manufacturing apparatus 5, the shaping machine 6, and the resistance value detector 7, and discharge the non-defective and defective products from the resistance value detector 7. Alternatively, an automatic conveying means may be used.

According to the first embodiment configured as described above, the control device controls the resistor manufacturing device 5 based on the deviation value information.
And the distance between the welding points 3-3 of the lead terminals is corrected, so that the resistance value of the resistor manufactured by the correction almost falls within the allowable error range and becomes a good product.

(Embodiment 2) FIG. 2, FIG. 3 and FIG.
FIG. 9 shows a specific example of a resistor manufacturing device 5 in the current detection resistor manufacturing device according to the second embodiment of the present invention. FIG. FIG. 2 is a plan view showing a portion below the welding position, and FIG.
2 is an AA front view of FIG. 2 including a portion above the welding position, and FIG. 4 is a BB side view of FIG. 2 including a portion above the welding position.

In FIG. 2 to FIG. 4, reference numeral 11 denotes a work transfer unit movable in the direction of arrow C, and a chuck means 12 for chucking a strip-shaped resistor 1 cut to a predetermined size from a hoop material at a tip end thereof. The chucked resistor is transferred from the chuck position to the welding position 13, and after the lead terminal 2 is welded, the resistor is transferred to the chuck position.
(FIG. 2 shows this state.) Release the chuck. Note that FIG.
In the description, resistors 1 'of different sizes are also described, and resistors of various sizes can be chucked.
(Incidentally, 1 indicates the minimum dimension and 1 'indicates the maximum dimension). Numeral 14 denotes a positioning means for positioning the strip-shaped resistor 1 to be supplied to the work transfer unit, which can be adjusted according to resistors of various sizes.

Reference numeral 15 denotes a pair of lead terminal supply units disposed on the left and right sides of the work transfer unit 11, which feed a continuous amount of electric wires and cut the lead terminals into predetermined dimensions by an air nipper 16 (see FIG. 4). Supply. As a specific example, a feed portion that moves a predetermined distance in the lateral direction in addition to a part of the wire, and after sending a predetermined amount, when the feed portion returns, it is composed of a holding portion that prevents movement of the wire, It is not limited to this configuration.

Reference numeral 17 denotes a lead terminal transfer unit for holding the lead terminals supplied from the lead terminal supply unit 15 and transferring them to the welding position 13. Lead terminal transfer unit 17
Is provided with a split groove at its tip, and when it moves in the direction of arrow D to the lead terminal supply position, the lead terminal is held in the split groove. Then, connect the lead terminal to the welding position
Then, one end of the lead terminal is positioned at a welding point near both ends of the resistor transferred by the work transfer unit 11. Reference numeral 18 denotes an air cylinder for moving the lead terminal transfer unit 17.

Reference numeral 21 denotes a pair of welding units for sandwiching the resistor 1 and the lead terminal 2 set at the welding position between the upper and lower welding electrodes 22 and 23 and applying current to perform welding. Welding electrode
22 and 23 are held by holders 24 and 25, respectively.
24 and 25 are rotatable around support shafts 26 and 27 provided at one end. That is, during welding, the member 29 is
Is pushed out in the direction of arrow E to push up the lower holder 25,
The lower welding electrode 23 is lifted up by about 1 cm and is brought into contact with the lower side of the welding portion of the resistor 1. On the other hand, the upper holder 24 is pushed down by the operation of the press machine 31 (from the position of the dotted line to the position of the solid line), and presses the welding end of the lead terminal 2 with the upper welding electrode 22. Then, an electric current is applied, and spot welding is performed by Joule heat at that time. FIG. 3 shows a state at the time of welding. Numeral 32 denotes an elastic body, and when the lead terminal 2 is deformed by welding, it immediately follows the deformation and maintains the pressing force.

Reference numeral 33 denotes a pair of frames 34 on which the welding unit 21 and the lead terminal transfer unit 17 are mounted, respectively.
It is a pair of frame displacement means for minutely displacing in the direction of arrow F to a position designated by the control device.

Next, the operation of the second embodiment will be described. First, a strip-shaped resistor 1 cut to a predetermined size from a hoop material (not shown) is set on the positioning means 14, and a start button is pressed. The work transfer unit 11 moves to the position of the positioning means 14, the chuck means 12 chucks the resistor 1 and returns to the welding position 13.

At the same time, the lead terminal supply unit 15 feeds a continuous amount of electric wire and cuts it into a predetermined size by the air nipper 16. The lead terminal transfer unit 17 having a split groove at the tip thereof moves there, holds the lead terminal 2, moves to the welding position 13, and aligns one end of the lead terminal 2 with the welding location of the resistor 1.

Next, the holders 24 and 25 are rotated by the operation of the cylinder 28 and the pressurizing machine 31, so that the resistor 1 and the lead terminal 2 are sandwiched between the upper and lower welding electrodes 22 and 23 and pressurized. Then, current is supplied from a welding power source (not shown) to perform welding.

When the welding is completed, the welding electrode 22 and the welding electrode 23 are separated from the resistor, and the resistor is moved to the work transfer unit.
It is transferred to the position of the positioning means 14 by 11 (FIG. 2 shows the state), the chuck is released, and the resistor manufacturing apparatus 5
Taken out of

FIG. 5 shows an example of the shaping machine 6.
The resistor taken out from the resistor manufacturing device 5 supports the work.
Positioned on the folding stage 37 supported by 36. Then, first, the presser pin 38 descends to press the center of the resistor, and the work support 36 retreats. Next, the pair of bending tools 39 descends to bend the resistor according to the shape of the bending stage 37. The bending position of the shaping machine 6 can also be adjusted according to various sizes of the resistor.

FIG. 6 shows an example of the resistance value detector 7. The lead terminal portion of the bent and shaped resistor is inserted into a predetermined position. Then, an accurate constant current flows from the pair of contact terminals 41 that come into contact with the lead terminals, and the voltage between the resistors is measured at the other pair of contact terminals 42, and the resistance value is measured by a so-called four-terminal method. .

In this resistance value detector, a target resistance value is set, and whether the resistance value of the manufactured resistor is positive or negative with respect to the target resistance value, is within an allowable deviation value (pass), or deviates from it. Is displayed (failed), and if defective, an alarm is given by a lamp or buzzer. Further, even within the allowable deviation value, if it exceeds a certain range, information on a deviation value from the target resistance value is output and fed back to the control device. The control device is shown in FIG.
As described in the above, a signal is sent to the resistor manufacturing apparatus 5, and control is performed so as to correct the welding portion of the lead terminal of the resistor in order to make the deviation value close to zero.

According to the current detecting resistor manufacturing apparatus of the second embodiment constructed as described above, if the material is supplied to the positioning means of the resistor manufacturing apparatus, the optimum position of the resistor is automatically adjusted. Since the lead terminals are welded, the current detection resistor can be manufactured with extremely high yield.

[0030]

As described above, according to the present invention,
Even if there is variation in the resistance value of the hoop-shaped resistor, control is performed by measuring the resistor manufactured by the resistor manufacturing device with a resistance value measuring instrument and feeding back the deviation value information at that time to the control device. Since the device controls the resistor making device to correct the welding point of the lead terminal on the resistor so that the deviation value approaches 0, the next corrected resistor always has the resistance value within the allowable range. This has the effect that a highly reliable, extremely low resistance, high precision current detection resistor can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a block diagram of an apparatus for manufacturing a current detection resistor according to Embodiment 1 of the present invention.

FIG. 2 is a plan view showing a portion below a welding position of a resistor manufacturing device in a current detection resistor manufacturing device according to a second embodiment of the present invention.

FIG. 3 is an AA front view of FIG. 2 including a portion above a welding position in the resistor manufacturing apparatus.

FIG. 4 is a BB side view of FIG. 2 including a portion above a welding position in the resistor manufacturing apparatus.

FIG. 5 is a front view of a shaping machine in a current detection resistor manufacturing apparatus according to a second embodiment of the present invention.

FIG. 6 is a front view of a resistance value measuring instrument in a current detection resistor manufacturing apparatus according to Embodiment 2 of the present invention.

FIG. 7 is a perspective view of a current detecting resistor manufactured by the manufacturing apparatus of the present invention.

FIG. 8 is a diagram showing a dimensional relationship for determining a resistance value of the current detecting resistor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Resistance element, 2 ... Lead terminal, 3 ... Welding point, 5
... Resistor manufacturing device, 6 ... Shaping machine, 7 ... Resistance value detector, 8 ... Control device, 11 ... Work transfer unit, 12 ...
Chuck means, 13 ... welding position, 14 ... positioning means,
15 ... Lead terminal supply unit, 16 ... Air nipper,
17… Lead terminal transfer unit, 21… Welding unit,
22,23… Welding electrode, 24,25… Holder, 31… Pressurizer, 33… Frame displacement means, 38… Presser pin, 39…
Bending tools, 41,42… Contact terminals.

Claims (3)

[Claims] 1. A resistor manufacturing apparatus for manufacturing a resistor by welding lead terminals near both ends of a strip-shaped resistor, respectively.
A resistance value measuring device for measuring the resistance value of the manufactured resistor and judging pass / fail and outputting deviation value information from a preset resistance value, and inputting the deviation value information, and setting the deviation value to 0
And a control device for controlling the resistor manufacturing device so as to correct a welded portion of the lead terminal of the resistor so as to approach the resistance value. 2. The current detecting resistor according to claim 1, further comprising a shaping machine for bending a resistor taken out of the resistor manufacturing apparatus so that the lead terminals face in the same direction. Manufacturing equipment. 3. A resistor manufacturing apparatus, comprising: chuck means for chucking a strip-shaped resistor cut into a predetermined size from a hoop material; transferring the chucked resistor from a chuck position to a welding position; And a work transfer unit for transferring the resistor to the chuck position and releasing the chuck after welding, and a lead terminal arranged on both the left and right sides of the work transfer unit for feeding a certain amount of continuous electric wires and cutting to a predetermined size. A pair of lead terminal supply units, and the supplied lead terminals are clamped and transferred to the welding position, and one end of the lead terminal is aligned with a welding portion near both ends of the resistor transferred by the work transfer unit. A pair of lead terminal transfer units, and a resistor and a lead terminal set at the welding position are separated by upper and lower welding electrodes. A pair of welding units for sandwiching and welding by passing an electric current; and a pair of frame displacing means for minutely displacing a pair of frames respectively mounting the welding unit and the lead terminal transfer unit to a position instructed by the control device; The apparatus for manufacturing a current detection resistor according to claim 1 or 2, further comprising: