JPS63295059A - Automatic soldering method - Google Patents

Abstract

PURPOSE:To decrease the amt. of a residual flux by detaching fluxcored wire solder once from a soldering point and resetting the same again after the start of soldering and before the end thereof at the soldering point on a work. CONSTITUTION:The flux cored wire solder 30 is supplied from a soldering nozzle 36 of an automatic soldering device to the soldering point 32 of the work wound with an electric wire 70 on a riser 68 and is heated to melt by an iron tip 66, by which the soldering is executed. The above-mentioned wire solder 30 is once detached from the soldering point 32 by controlling the above- mentioned soldering nozzle 36 after the start of the soldering at the soldering point 32 on the work. The molten solder contg. the flux in a region (b) apart from the iron tip 66 is thereby detached from the solid solder in the region (c) and is absorbed to the solder in the region (a) of a high temp. The flux of this solder is evaporated by heating the same to a high temp. with the iron tip 66. The solder 30 is thereafter reset again and the soldering is continued. The above-mentioned operation is carried out at least once before the soldering ends. The amt. of the residual flux at the soldering point 32 is thereby decreased and the good soldering is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for automatically soldering soldering points on a workpiece using flux-cored thread solder.

BACKGROUND OF THE INVENTION Conventionally, a commutator of a micromotor has a plurality of soldering points arranged circumferentially, as shown in FIG. The (A> figure is a front view, and the (B) figure is a side view. In the figure,
10 is a commutator that forms the rotor of the micromotor together with the armature and shaft.

12 (12a to 12C) are three-pole commutator pieces, which are arranged at equal intervals on the circumference of an insulating cylinder 16 having a shaft hole 14 in the center with a certain insulating space between them. 18(
18a to 18C) are risers provided at one end of each commutator piece 12. These risers 18 are terminals of the commutator piece 12, and the riser 18 connects the commutator piece 12 and the armature winding 20 as shown in FIG. For this purpose, the electric wires 22 (22a, 22b) etc. from the armature winding 20 are tied to the respective risers 18 and soldered thereto. This armature winding 20 generally uses a polyurethane coated electric wire. Therefore, the electric wire 22 that is tied around or hooked onto the riser 18 is also a polyurethane coated electric wire. Further, 24 is an armature, and 26 is its shaft. In this way, a plurality of half-F points are arranged on the circumference of the commutator 10 of the micromotor. Note that the soldering points corresponding to five-pole, seven-pole, nine-pole micromotors, etc. are similarly arranged depending on the polarity.

Soldering workpieces with multiple soldering points on the circumference is generally done using flash-cored thread soldering (
It is hand soldered using wire-core solder. In addition, an automatic soldering device using similar flux-cored thread solder has already been developed, and the present applicant previously filed a patent application in 1983-133.
680g, Utility Application No. 1984-97247, Patent Application No. 1983-2
We have filed applications such as No. 86602 and Japanese Patent Application No. 114449/1986. However, no matter which method is followed, if 7 lux remains in the vicinity of the soldering point after soldering is completed, there will be a problem. In particular, in the commutator 10 of a micromotor, the contact surface of the brush on the commutator piece 12 and the riser 18 are very close to each other, so flux easily adheres to the contact surface of the brush, and if left as is, the contact resistance increases.

Therefore, the commutator is usually subjected to ultrasonic cleaning using a liquid such as trichloroethane, and then polished with sandpaper to remove residual flux. Note that polishing with sandpaper may cause scratches on the commutator surface. For this reason, in both manual and automatic soldering, it is required to minimize unnecessary residual flux near the soldering points. but,
Currently, compared to the amount of flux left by skilled workers, there is usually more flux left behind by automatic soldering. Also, the more 7 lux remains, the worse the soldering condition is and the higher the defect rate.

In the patent application No. 61-114449 filed earlier, the present applicant proposed an automatic soldering nozzle that continuously delivers flux-cored solder wire to the soldering point on the workpiece from the start of soldering to the end of soldering. A soldering device is presented.

Problems to be Solved by the Invention However, the solder thus delivered is in a molten state near the soldering point on the workpiece as shown in FIG. 1A. In other words, area a is the area where the solder has melted at the soldering point, area b is the area that is slightly away from the soldering point but has melted solder, and area C is the area where the solder is not melted at all. It is. In such a state, the flux in the area a is heated to a high temperature (approximately 400 to 500'C) by the soldering iron tip, so it effectively acts as a solvent during semi-aluminum bonding, and then evaporates. However, since the flux in area b is far from the iron tip, it is heated as the solder melts and becomes liquid, but it takes time for it to be delivered and reach area a. Therefore, it does not work effectively and evaporates t! Instead, a large amount of material adheres and remains near the soldering points, causing the problems described above. Note that the area C is used for soldering at other soldering points.

The present invention was made in view of these conventional problems, and it is an object of the present invention to provide an automatic soldering method with less residual flux.

Means for Solving the Problems Means for achieving the above object will be described below with reference to FIG. 1, which corresponds to an embodiment.

In this automatic soldering method, the soldering point 32 on the workpiece is
After the soldering starts and ends, the first soldering nozzle 36 provided in the automatic soldering device is controlled.
From the soldering nozzle 36 to the soldering point 3 as shown in Figure A
The flux-cored solder wire 30 sent to No.2 is transferred to No.1B.
As shown in the figure, the soldering point 32 is temporarily detached from the soldering point 32 and returned again at least once.

action The above means works as follows.

After starting soldering at soldering point 32 on the workpiece,
By the end of the process, from the soldering nozzle 36 to the soldering point 3
The flux-cored solder wire 30 that is being sent to area 2 is separated from the soldering point 32 - and the melted solder in area b is separated from the solid solder in area C and placed in area a. It is rapidly attracted to the hot melted solder. Therefore, the flux that was in the area b also moves rapidly to the area a, and is heated to a high temperature by the iron tip 66. As a result, the flux also acts effectively on soldering, and then evaporates. The solder 30 once removed in this way is moved downward again and returned to the soldering position, and the soldering is continued. In addition, 1g
The amount of residual flux can be reduced by appropriately selecting the number of times the solder is removed and returned to the soldering point 32 from the start to the end of soldering.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a process diagram showing an automatic soldering method according to an embodiment of the present invention, Fig. 2 is a front view showing a nozzle shift unit of an automatic soldering apparatus that implements the method, and Fig. 3 is a side view thereof. , FIG. 4 is a block diagram showing the main parts of the circuit that controls the unit.

In the figure, 30 is a flux-cored solder wire in which 7 lux is packed in the center of the metal alloy. This solder thread 30 is wound around a solder pulley, and a solder feed unit moves one or more threads simultaneously to the soldering point 30 on the workpiece.
2 in sequence.

At that time, the thread solder 30 is fed from the motor pulley 34 provided on the main shaft of the solder feed motor at a feeding force of 17, and the solder nozzle (
Insert the sleeve) 36 in its longitudinal direction (direction of arrow X)
Proceed along toward soldering point 32. In addition, 3
8 is a motor pulley 3 in order to give a sending force to the thread solder 30.
This is a solder crimping feeding pulley that crimps the thread solder 30 on the solder wire 30.

In order to prevent the tip of the solder wire 30 fed in this manner from hitting the soldering point 32, a small distance is maintained between the two in a direction perpendicular to the longitudinal direction.

40 is a nozzle shift unit that moves the solder nozzle 36 in a direction approximately perpendicular to its longitudinal direction. This nozzle shift unit 40 is supported by a common board 42 with the solder feeding unit.

44 is a branch whose one end is fixed to the base plate 42, and a slide unit 46 and a cylinder unit 48 are respectively arranged at predetermined positions on the column 44. This slide unit 46 consists of a fixing member 50 screwed to the lower middle of the column 44, and a slide member 54 to which a member 52 for holding the solder nozzle 36 is screwed. Further, 56 is used to connect the solder nozzle holding member 52 and the like to the common substrate 4.
It is supported by pushing up on 2, and is covered with a compression spring that gives it elasticity. Therefore, by pressing the upper end of the holding member 52, the position of the solder nozzle 36 can be moved downward and adjusted, and the tip of the solder thread 30 and the soldering point 3
2 can be selected. The cylinder unit 48 also has a support 5 that protrudes from the upper end of the column 44.
It consists of a cylinder 60 fixed at 8, and a piston 62 protruding from the cylinder 62 in response to a predetermined air pressure. In addition, 64
is an air tube communicating with the inside of the cylinder 60.

When the air pressure sent from the air duplex 64 to the cylinder 60 is increased, the piston 62 protrudes downward, and its tip presses down the upper end of the solder nozzle holding member 52 against the push-up blade of the spring 56. Then, the solder nozzle 36 moves downward, and the solder thread 30 also moves downward (in the direction of the arrow Y), eliminating the above-mentioned separation distance and moving its tip above the soldering point 32, where it moves. 3rd to
As shown in the figure, it can be placed securely and brought into close contact.

Then, the tip 66 of the half-day trowel is inserted in the direction of the arrow.

Note that such a soldering point 32 is a place where the electric wire 70 is wound around the lie (Aro 8).

In this manner, soldering at the soldering point 32 is started. In this state, as shown in FIG. 1A, the area a is the part where the half EEI has melted at the soldering point 32, the area b is a part slightly away from the soldering point 32, but the solder is melted, Region C is a portion where the solder is not melted at all. If soldering is continued in this state, the problem described above will occur. Therefore,
The flux-cored solder wire 30 being fed from the solder nozzle 36 to the soldering point 32 is once removed from the soldering point 32 as shown in FIG. 1B. At this time, when the air pressure of the air tube 64 is lowered, the piston 62 retreats upward, so that the solder nozzle holding member 52, which always receives the push-up blade of the spring 56, returns to the position before starting soldering, and the solder nozzle 36 also moves. Rise in the direction of the arrow. Therefore, the melted solder in the area b is separated from the solid solder in the area C, and is rapidly attracted to the high temperature melted solder in the area a. At the same time, the flux that was in the region b also rapidly moves to the region a, and is heated to a high temperature by the iron tip 66.

As a result, the flux also acts effectively on soldering, and then evaporates. Next, the once removed solder is moved downward again to return to the previous soldering position, and soldering is continued. In order to control the solder nozzle 36 in this manner, it is necessary to apply a drive signal corresponding to the cylinder 60. Therefore, a soldering iron light driving circuit 7 as shown in FIG.
A timer 74 receiving a signal from the cylinder drive circuit 76 is used to generate a signal to be sent to the cylinder drive circuit 76. For example, solder nozzle 3
After moving 6 downward and placing it in the soldering position for 0.3 seconds,
A signal is generated to perform control such as moving it upward, moving it downward again after 0.1 period, and returning it to the previous soldering position. At the end of soldering, the solder nozzle 36 is raised to separate the tip of the solder thread 30 from the soldering point 32, and then the soldering iron is further retreated to keep the tip 66 from the soldering point 32. In addition, if the number of times of solder separation and return from the start to the end of soldering for one soldering point 32 is selected appropriately, the residual flux can be reduced to the same level as manual soldering by a skilled worker, or even worse. It can be reduced even more.

According to the present invention, which has been described in detail, residual flux at soldering points on a workpiece can be reduced. Therefore, the defect rate in the soldered state is also reduced.

[Brief explanation of the drawing]

Fig. 1 is a process diagram showing an automatic soldering method according to an embodiment of the present invention, Fig. 2 is a front view showing a nozzle shift unit of an automatic soldering apparatus that implements the method, and Fig. 3 is a side view thereof. , FIG. 4 is a block diagram showing the main parts of the circuit that controls the unit. Fig. 5 is a diagram showing a commutator of a micromotor as an example of a workpiece having soldering points. FIG. 3 is a side view showing the vicinity of the brush side of the assembled rotor.

Claims (1)

[Claims] After starting and finishing soldering at the soldering point on the workpiece, the flux-cored solder wire being sent from the soldering nozzle to the soldering point is temporarily soldered by controlling the soldering nozzle installed in the automatic soldering device. An automatic soldering method characterized by separating from a soldering point and returning to the soldering point at least once.