JP3219283B2 - Welding equipment for metal parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal member welding apparatus, and more particularly, to welding of a metal wheel for a caster, a so-called caster core, or the like, for welding a bowl-shaped metal wheel material constituting a plated metal part. The present invention relates to a welding apparatus that can prevent discoloration of a plating layer at a welding portion and generation of harmful smoke due to burning of a plating, and can improve strength and airtightness of a welding portion.

[0002]

2. Description of the Related Art Conventionally, casters having wheels formed by baking rubber members on the outer periphery of a hollow metal wheel have been widely used in carts for carrying goods, and such casters are used for machinery and furniture. It is also used for such purposes.
By the way, since a few casters usually support the entire load of a bogie, machinery, or the like, the wheels must have sufficient mechanical strength to withstand a considerably large load. For this reason, the metal wheel of the above-mentioned wheel was generally manufactured by firmly joining a pair of bowl-shaped metal wheel materials by welding.

FIGS. 7, 8 and 9 are views for explaining a conventional example of a method of welding the above-mentioned metal wheel.
FIGS. 8 (a) to 8 (c) and FIGS. 8 (a) and 8 (b) are perspective views showing the outline of the cross-sectional structure and appearance of the metal wheel divided into main assembling stages, respectively, and FIGS. 9 (a) to 9 (c). ) Are cross-sectional views showing a detailed cross-sectional structure of the metal wheel.
(c) is supported. In the figure, reference numerals 1a and 1b denote a pair of bowl-shaped metal members constituting the metal wheel 1.
It has a substantially cylindrical shape (outside diameter X) with a bottom that has an open upper surface,
Component mounting holes 2a and 2b for mounting the bearing member 4 are formed in the center of the bottom surface. Reference numerals 3a and 3b denote annular grooves formed on the bottom surface of the metal members 1a and 1b, respectively, for reinforcing the wheel body.
0b is an opening peripheral part of the metal members 1a and 1b,
The outer peripheral surface of the cylindrical shape having the outer diameter X coincides with the outer peripheral surface (FIG. 9).
(a)). Reference numerals 10a ₁ and 10b ₁ denote thick portions formed by making the ends of the opening peripheral portions 10a and 10b have a wall thickness over the entire periphery thereof. Can be provided.

That is, the above-mentioned bowl-shaped metal member is formed by pressing a flat plate of a predetermined size between upper and lower mold frames and pressing the metal member immediately after this pressing. The brim remains. Therefore, after the pressing step, there is a step of cutting off the brim portion, that is, trimming. At the time of this trimming, as shown in FIG. 9 (a), the collar portion is cut off along a circumference (diameter X ₁ ) larger than the outer diameter X of the opening peripheral portion by the thickness t of the flat plate. Opening edge 10a
It is possible to form the thick portion 10a ₁ on the opening side end portion of the. This thick portion is not shown in FIGS.

[0005] 7 is a welded portion of the contact portion of the opening edge of both the metal members, that is, the thick portion 10a _1, 10b ₁ and joined by CO ₂ welding. 8a is the CO ₂
A welding torch for performing welding, which is attached to an automatic welding apparatus main body (not shown). Nozzle 8c torch body 8a, as well as feed the welding wire 8c _1, the welding portion to inject a shielding gas for shielding from air
And a cable portion 8b for connecting the nozzle 8c to the welding device main body side.

As shown in FIG. 9 (c), the bearing member 4 includes left and right bearings 4a and 4b, and an intermediate pipe 44 as a spacer interposed between these bearings. The left and right bearing portions 4a, 4b are respectively provided with inner pipes 41a ₁ , 41 fitted with a shaft member (not shown).
and b _1, it has component mounting hole 2a of the bowl-shaped metal member, an outer pipe 41a _2, 41b ₂ to 2b mating bearing 42a interposed between the pipe, and 42b. 43a ₁ and 43b ₁ are the outer pipes 41a, respectively.
₂ , 41 b ₂ , an outer annular cover fixed to 43, 43
a ₂ and 43b ₂ are inner annular covers fixed to the outer pipes 41a ₂ and 41b ₂ .

Next, the welding method will be described. First, as shown in FIGS. 7 (a) and 7 (b), a pair of bowl-shaped metal members 1 are formed.
a, 1b of the automatic welding apparatus chucks These opening edge 10a (not shown), 10b thick portion 10a ₁ of
Superimposed to 10b ₁ are in contact, joining the contact portions CO ₂ welding, as shown in Figure 8 (b). Then, the metal wheel 1 thus welded is immersed in a plating solution to perform a plating process, and thereafter, a rubber member is baked on the outer peripheral surface of the metal wheel 1 to form a tire portion 5, and further, the component mounting of the wheel 1 is performed. The left and right bearings 4 are provided in the holes 2a and 2b.
a and 4b are press-fitted with the intermediate pipe 44 interposed between the two bearing portions. As a result, the wheels 15
Is completed (FIG. 7 (c)). The reason why the intermediate pipe 44 is interposed here is to prevent the metal members 1a, 1b from being deformed due to the two bearings 4a, 4b approaching at a predetermined distance or more during press fitting. Finally, a shaft member (not shown) is fitted into the bearing member 4, and a bracket or the like (not shown) for supporting the shaft member on a carriage for carrying cargo is attached to the shaft member to complete the caster. I do.

[0008]

However, in the production of such a conventional caster, a pair of bowl-shaped metal members 1 are required.
The thick portions 10a ₁ , 10b ₁ of a, 1b are cut along the
Since the metal wheel 1 is formed by joining by O ₂ welding, it is necessary to weld uniformly and accurately over the entire circumference, and when uniformity or accuracy is poor, for example, a pinhole or the like is formed in a welded portion. If it occurs, there is a problem that a problem such as a failure to perform the rubber baking process properly occurs.

[0009] Further, if the plating treatment is performed before the arc welding, the heat of the arc welding causes discoloration of the plated layer, generation of harmful smoke due to burning of the zinc plating, and peeling of the plated layer. Therefore, conventionally, the plating process was performed after arc welding. In this case, a plating solution, a washing solution, and the like accumulate in the recess inside the metal wheel.
There was a problem that it was troublesome to discharge these.

The present invention has been made in order to solve the above-mentioned problems, and a pair of metal members constituting a metal part, such as a metal wheel of a caster, can be uniformly formed in a short time. Welding can be performed while minimizing the heating of the parts other than the welded parts, thereby improving the workability of welding and improving the airtightness and strength of the welded parts.In addition, when plating is performed before welding Another object of the present invention is to provide an apparatus for welding metal members capable of preventing discoloration, generation of toxic gas, and peeling of plating due to heat in a plated portion.

[0011]

[0012]

[0013]

[0014]

According to the present invention, there is provided an apparatus for welding a metal member according to the present invention, wherein a metal member having a substantially cylindrical shape having a bottom and an open upper surface is accommodated in an inner wall surface of the metal member. A pair of welding electrode members each having a component housing portion formed in a shape that is in close contact with the bottom surface of the opening and the outer surface of the opening peripheral edge portion, and driving the pair of welding electrode members so as to come close to each other to contact the opening peripheral edge portion. A pair of metal members superposed and overlapped are accommodated in the component accommodating portions of the respective welding electrode members, and in this state, both metal members are provided with pressure contact means for press-contacting the ends of the opening peripheral edges so as to be in close contact with each other. Primary input is low voltage on both sides of the welding electrode
Two transformers for converting the current into a secondary output of a large current and supplying a welding current to the both welding electrode members are arranged, and the control means controls the pressure welding means and the two transformers to control the welding. The welding voltage is applied between the two welding electrode members for a required time while the pair of metal members are pressed against each other by the electrode members.

[0015]

[0016]

[0017]

[0018]

[0019]

According to the present invention, a pair of approaching and releasable welding electrode members each having a component accommodating portion for accommodating a metal member, and a pair of opposing metallic members are driven by bringing the welding electrode members into close proximity to each other. And a transformer for converting a primary input into a low-voltage, high-current secondary output on both sides of the pair of welding electrode members, respectively. In a state in which each of the members is housed in the component housing portion of the pair of welding electrode members in such a manner that the outer surface of the peripheral edge of the opening of the metal member and the inner wall surface of the component housing portion are housed in close contact with each other, While the members are pressed against each other so that the peripheral edges of the openings are in close contact with each other, a low-voltage and large-current power is supplied between the two welding electrode members in a short time. Can be automated and also By the genus members made adding device continuously supplied onto the welding electrode member, it is possible to mass-produce the metal wheel for use in casters, can be reduced the production cost.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing the overall configuration of a welding apparatus, FIGS. 2 and 3 are front views and plan views showing an enlarged view of a welding electrode member of the welding apparatus and peripheral parts thereof, and FIG. FIG. FIG. 5 is a view for explaining the operation of the welding apparatus, FIG. 6 is a view showing a relationship between welding current and a pressing force applied to a pair of members to be welded, and FIG. 7 is a perspective view showing wheels of the caster for each manufacturing process. It is a diagram, also in the present invention, since the metal member constituting the metal wheel of the caster has exactly the same structure as that described in the conventional example, in the description of this embodiment, the metal member The thick part of the peripheral edge of the opening is not shown.

In FIG. 1, reference numeral 100 denotes a pair of plated metal members 1a and 1b having a substantially cylindrical shape having a bottom with an open upper surface, the openings being opposed to each other, and a peripheral edge 10a of the opening. , 10b are welded and joined to each other, and a pair of upper and lower welding electrode members 400a, 400 arranged at the center of a gantry 101 formed by combining channel steel.
0b, a pressing mechanism for driving the upper welding electrode member 400a downward and pressing the pair of metal members 1a and 1b, and a second pressing mechanism disposed on both sides of the welding electrode member on the gantry 101. It has first and second transformers 210 and 220, and a control device 300 for controlling the press-contact mechanism and both transformers. Here, in the case where the member to be welded is relatively small, for example, a diameter of about 10 cm or less, good welding is possible even with one transformer, but if the member to be welded is larger, one transformer is required. Therefore, in the portion of the member to be welded opposite to the transformer, the distance from the transformer is longer than that of the portion on the transformer side, that is, the impedance of the welding current path increases accordingly, so there is a possibility that welding may not be performed well. . For this reason, in the present embodiment, the transformers are arranged on both sides of the welding electrode members 400a and 400b so that good welding can always be performed.

Here, each of the above welding electrode members 400a, 40
0b is an electrode fixing base 120a, 1 made of brass, respectively.
20b and bolts 110a ₁ , 110b
Copper welding electrodes 110a and 110b fixed to ₁
And the lower welding electrode 110b
Has a component housing portion 111b having a concave cross section formed in such a shape that the bottom outer surface and the side surface of the opening peripheral portion 10b and the inner wall surface of the metal member 1b are in close contact with each other when the bowl-shaped metal member 1b is housed. and has parts insertion hole 111b ₁ is formed in its bottom center. Note 120b ₃ are inserted through holes in the bolt 110b ₁ which is formed on the electrode fixing base 130b.

[0023] Similar to the welding electrode 110b also lower welding electrode 110a of the upper has a component accommodating portion 111a for accommodating the metal member 1a, larger parts than the parts insertion hole 111b ₁ on the bottom surface center insertion holes 111a ₁ is formed.

Reference numeral 102 denotes a component mounting table provided at the center of the gantry 101, and its mounting bracket 102a is fastened and fixed to the gantry 101 by bolts 102b so that the height can be adjusted. On the upper surface of the mounting table 102, a lower platen 130b made of brass having electrode connection brackets 131 on both sides is mounted via an insulating spacer member 103. And on the lower platen 130b the welding electrode member 400b is fastened by a bolt 120b _1. The lower platen 130b
Has a water circulation passage 134 formed therein. During welding, water flows through the circulation passage 134 so that the platen table itself and a welding electrode member 400 mounted thereon are formed.
b is cooled. Reference numerals 132 and 133 denote water supply and drain pipes for supplying and discharging water to and from the circulation passage 134, respectively.

Reference numeral 150 denotes a pneumatic cylinder device which is disposed above the component mounting table 102 and constitutes the press-contact mechanism. An upper platen 130a having an electrode connection bracket 131 is attached to the lower end of the sliding rod 151. ing. This is the lower surface of the upper platen 130a and the welding electrode member is clamped by a bolt 120a _1, and this is the upper platen 130a circulation passage 134 of the same water and the lower platen 130b are formed, the circulation passage 134 Water and drain pipes 132,1 at both ends
The upper platen itself and the welding electrode member 400a are cooled during welding.

Reference numerals 141 and 142 denote secondary outputs of the left and right transformers 210 and 220, respectively, to the lower platen 130.
b, a conductor member having a substantially U-shape in a plane for guiding the water to the inside, and a water circulation passage 143 is formed therein.
Water supply and drainage tubes 143c, 143
d is connected. The U-shaped conductor member 142
Of the upper and lower sides are fixed to the electrode connection bracket 131 of the lower platen 130b by bolts 142a, and the back side thereof is connected to the transformer 220 by bolts 142a.
Is fixed to one terminal 223 of the secondary side output. 1
42b is a washer attached to each bolt 142a. In FIG. 2, the conductor member 142 on the right side of the lower platen
Only the connection between the secondary output terminal of the transformer 210 on the left side and the lower platen 130b is performed by the conductor member 141 on the left side in exactly the same manner.

Reference numerals 214 and 224 denote the secondary outputs of the left and right transformers 210 and 220, respectively.
It is a side-reverse U-shaped flexible conductor member for leading up to 30a, which is formed by laminating a plurality of thin copper plates, and is flexibly bent in accordance with the vertical movement of the platen 130a. Each flexible conductor member 214, 22
4 is attached to the electrode connection bracket 131 of the upper platen 130a by bolts 215a and 225a.
14a and 225a, and the other ends are respectively applied to the other terminals 212 and 222 of the secondary outputs of the left and right transformers 210 and 220, respectively.
a.

Here, both terminals 212, 213, 222 and 223 of the secondary side output of each of the transformers 210 and 220 are described.
Is mounted so as to be vertically adjustable via each of the transformer bodies and insulating plates 211 and 221 so that the distance between the upper and lower terminals of the secondary output can be adjusted according to the type of the member to be welded. Has become.

Each of the transformers 210 and 220 and the pneumatic cylinder 150 are driven and controlled by a control device 300. Specifically, the control device 300
The pair of upper and lower welding electrode members 400a and 400b are driven close to each other by the pneumatic cylinder 150 to press the pair of bowl-shaped metal members 1a and 1b into contact with each other. After reaching a predetermined value in the range of 1,000 to several thousand kgf / cm 2, the welding voltage is applied for 1/60 [seconds / cycle] × several [cycles] to tens of cycles [cycles]. And then apply 1/6
The setting is such that the pressing force is released after 0 [sec / cycle] × several tens of cycles have elapsed. Here, the time from the start of the pressing of the bowl-shaped metal member to the application of the welding voltage is set to about 1/60 [sec / cycle] × several tens [cycles] to allow for a margin.

Next, a method of manufacturing a caster, particularly a method of welding a metal wheel of a caster will be described. Here, a case will be described in which a mild steel wheel having a diameter of 6 inches and a wall thickness of 1.6 mm is used as a metal wheel to be welded.

In the method of manufacturing a caster according to the present embodiment, before welding the metal wheel 1, the pair of bowl-shaped metal members 1a and 1b constituting the wheel are preliminarily plated. Then, as shown in FIG.
Initial state in which 00a and 400b are separated (FIG. 5 (a))
, The member housing portion 111 of the lower welding electrode 110b
One of the plated bowl-shaped metal members 1b is fitted into the plate b (FIG. 5 (b)). Then fitted fixed to the member insertion hole 111b ₁ of the lower welding electrode 110b, the insulating rod 160 for positioning through component mounting holes 111b ₁ of the bowl-shaped metal member 1b (FIG. 5 (c)). Then the other bowl-shaped metal member 1a
The in component mounting hole 111a ₁ is inserted through the insulating rod 160 is disposed on the lower side of the bowl-shaped metal member 1b (FIG. 5
(d), (e)). By using the insulating rod 160 in this manner, the upper and lower bowl-shaped metal members 1a and 1b can be easily positioned such that the opening peripheral portions 10a and 10b coincide with each other.

When the control device 300 is turned on in this state, a series of welding operations starts. That is, the control device 30
In response to the control signal from 0, the pneumatic cylinder 150 is driven to lower the upper welding electrode member 400a, and at a position close to the lower welding electrode member 400b, the upper bottom surface of the welding electrode 110a and the upper bowl-shaped metal member 1a. Abuts on the upper surface of the pair of upper and lower bowl-shaped metal members 1a and 1b. At this time, as shown in FIG. 6, the applied pressure reaches 2,000 to several thousand kgf / cm2 very steeply. When about 1/60 [sec / cycle] × several tens [cycles] have elapsed since the start of pressurization, the left and right transformers 210 and 220 are driven by the control signal from the control device 300 to the respective secondary sides. , Tens of thousands to hundreds of thousands of amps, power of several to several tens of volts 1/60 [second / cycle] x several to several tens of cycles
Output for a while.

At this time, the large current is generated by the transformer 21 on the right side.
For 0, one of the secondary output terminals 212
The conductor member 214, the upper platen 130a, the upper welding electrode member 400a, the upper bowl-shaped metal member 1a, the lower bowl-shaped metal member 1b, and the lower welding electrode member 400
b, the lower platen 130b and the conductor member 141,
On the path leading to the other terminal 213, and for the transformer 220 on the left side, one of the secondary output terminals 2
22, a conductor member 224, an upper platen 130a, an upper welding electrode member 400a, and an upper bowl-shaped metal member 1
a, lower bowl-shaped metal member 1b, lower welding electrode member 4
00b, the lower platen 130b, and the conductor member 142, and flows along a path leading to the other terminal 223. Due to the large current, the contact portions of the upper and lower bowl-shaped metal members 1a and 1b with the opening edges 10a and 10b, more precisely, the thick portions (see FIG. 9) of the openings are heated and melted.

After stopping the supply of the large current, 1/60
[Second / cycle] × Several tens of cycles are maintained, and the pressure is maintained as it is. Thereafter, the pneumatic cylinder 150 is driven again to return the upper welding electrode member 400a to the initial position. A series of welding operations controlled by control device 300 is completed. During the operation of the welding device, cooling water is always supplied to the upper and lower platens 130a and 130b and the circulation passages 134 and 143 of the conductor members 141 and 142.

Thereafter, the metal wheel 1 on which the welding has been completed is taken out from the lower welding electrode 110b together with the insulating rod 160, and the following processing is performed. Specifically, as shown in FIG. 7 (b), a rubber member is baked on the outer peripheral portion of the metal wheel 1 on which the welding has been completed to form a tire portion 5, and a component mounting hole in the center of the metal wheel 1 is further formed. The wheel of the caster is completed by mounting the bearing member 4 on 2a and 2b (FIG. 7 (c)).

As described above, in the present embodiment, the pair of bowl-shaped metal members 1a and 1b, which have been plated in advance, are pressed against each other by the pair of welding electrode members 400a and 400b, and the opening peripheral portions 10a and 10b of each bowl-shaped metal member are pressed. 10b was brought into uniform contact with each other, a large current was applied to the two welding electrode members in this state, and the pressing force was maintained for a predetermined period of time after the current supply was stopped. Part), the welding current flows evenly, that is, the heating and melting of the contact portion are performed uniformly, and the contact portion is pressed down by a constant pressing force while the molten portion solidifies. It will solidify uniformly. As a result, a welded portion having a predetermined length can be welded in a short time and with good airtightness without causing the occurrence of thermal distortion. Thereby, the time of the welding operation can be shortened, the workability can be improved, and the quality of the metal wheel can be improved.
In addition, it is pulled by the strength tester Amsler etc.
The pressing strength is high, and particularly in a tensile test, a tensile strength of 8 t or more has been demonstrated. In addition, since the welding current flows only in the welded part, heat generation in other parts of the member to be welded can be suppressed. It is possible to avoid generation of smoke and peeling of the plating, and it is possible to eliminate inconvenience in performing plating before welding.

In the above embodiment, a mild steel wheel having a diameter of 6 inches and a thickness of 1.6 mm has been described as an example of a metal member to be welded, but the member to be welded is made of steel and stainless steel. May be. However, in the case of a stainless steel wheel (diameter 6 inches, thickness 1.6 mm), the pressing force at the time of welding,
Further, the welding current is set to be larger, and the energization time is set to be slightly shorter. Note that the time from the start of pressurization to the application of the welding current is preferably set to be longer than the above welding conditions in consideration of the increase in the pressing force.

In the above embodiment, the upper and lower metal members 1a and 1b are aligned with each other in the component mounting holes 1a and 1b.
The insulating rod 160 is inserted into the metal member 1b, and the upper welding electrode 110a is configured so that the metal member 1a can be sucked into the component accommodating portion 111a by evacuation. May be held by the welding electrode 110a so that the positioning of the two metal members is performed.

[0039]

[0040]

[0041]

[0042]

According to the welding apparatus for a metal member according to the present invention, a pair of approaching and releasable welding electrode members each having a component accommodating portion for accommodating the metal member are brought into close proximity to each other. A driving means for pressing a pair of metal members opposed to each other, and converting a primary-side input into a low-voltage, large-current secondary-side output on both sides of the pair of welding electrode members. The transformers were respectively arranged, and each of the pair of metal members was housed in the component housing portion of the pair of welding electrode members in close contact with the outer surface of the opening peripheral portion of the metal member and the inner wall surface of the component housing portion. In this state, a low-voltage and large-current power is supplied between the welding electrode members in a short time while a pair of metal members facing each other are pressed against each other so that the peripheral edges of the openings are in close contact with each other. On top of the effect in the method There is an effect that can automate the welding of the pair of metal members. In addition, by adding a device for continuously supplying a metal member onto the welding electrode member, it is possible to mass-produce the metal wheel and to reduce the production cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a welding device .

FIG. 2 is an enlarged front view showing a welding electrode member of the welding device and a peripheral portion thereof.

FIG. 3 is an enlarged plan view showing a welding electrode member of the welding device and a peripheral portion thereof.

FIG. 4 is a perspective view showing a structure of the welding electrode member.

FIG. 5 is a diagram for explaining the operation of the welding device.

FIG. 6 is a diagram showing a relationship between a welding current and a pressing force applied to a pair of bowl-shaped metal members in the welding method.

FIG. 7 is a diagram for explaining a method of manufacturing wheels of a caster.

FIG. 8 is a view showing a conventional method of welding a metal wheel by joining a pair of bowl-shaped metal members by welding.

FIG. 9 is a view showing a detailed cross-sectional structure of the bowl-shaped metal member.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B23K 11/00 B23K 11/02 B23K 11/16 B23K 37/04

Claims (1)

(57) [Claims] 1. A substantially cylindrical shape having a bottom with an open upper surface.
The peripheral edges of the opening of a pair of metal members to each other
And joining the two metal members, wherein the inner wall surface of the metal member is
The shape that is in close contact with the outer surface of the bottom of the metal member and the periphery of the opening
Pair of welding electrodes each having a component receiving portion formed in
The member and the pair of metal members are driven close to each other to open
A pair of metal members superposed by contacting the edge of the mouth
Each welding electrode member is housed in the component housing,
Press the metal member so that the edge of the opening
Press-contact means, and primary-side input devices disposed on both sides of the pair of metal members.
Is converted to a low-voltage, high-current secondary output, and the welding electrodes
Two transformers for supplying welding current between members, and pressure welding of the pair of metal members by the two welding electrode members
While the welding voltage is being applied to the welding electrode member for the required time.
Control the above-mentioned pressing means and two transformers
Metal member characterized by comprising control means for performing welding
apparatus.