KR101974883B1 - Manufacturing method of bolt using welding - Google Patents

Abstract

The present invention relates to a manufacturing method of a power transmission bolt using welding and, more specifically, relates to a manufacturing method of a power transmission bolt using welding, wherein a bolt and an object to be welded are individually prepared, and in a state in which the bolt is close to the object to be welded as one side is designated as a fixing base material, and the other side is designated as a moving base material, a current is supplied to soften the bolt and the object to be welded by using heat generated by electric resistance. In the state, the bolt and the object to be welded are pressurized and bonded to be semipermanently coupled to each other to increase productivity and produce a product having constant quality.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a bolt,

The present invention relates to a method of manufacturing a power transmission bolt using welding, more specifically, a method of preparing a bolt and a workpiece separately, one of which is a fixed base material and the other is a moving base material, And a bolt and a workpiece are softened by using the heat generated by the electric resistance, and a semi-permanent connection is made by press bonding in this state, so that a bolt for power transmission .

The power transmission bolts are formed on one side with screws for fixation to the fixture and the other on the other side with bolts formed in a hemisphere or other form for power transmission. As such a power transmitting bolt, there is a ball stud which is typical.

A typical ball stud is a member of a ball joint which is in contact with a spherical contact socket in the form of an annulus with a round bar on a metal sphere and is rotatable in any direction and at the same time has a high rigidity in the direction of translation, It is widely used for bonding.

Conventionally, the manufacturing process of the ball stud used in the prior art is to produce a cold forging which is composed of a head portion, a tapered portion and a tail portion which are annealed to increase the ductility of the material by eliminating internal cracks in the structural steel material, And the cold forging is subjected to heat treatment by quenching for improving hardness and tempering for enhancing viscosity.

Such cold and simple forming type bolster has many uneconomical problems such as a decrease in productivity and an increase in production cost because the work time is long due to the cutting process of cold forging and the material ratio is increased by the amount of cutting, There is a problem that it falls.

As a conventional technique related to such a ball stud manufacturing method, there is a ball stud forming method proposed for the stabilizer link proposed in Japanese Patent Application Laid-Open No. 10-2008-0114219.

The method of forming a ball stud for a stabilizer link in which a ball stud material is disposed in a dice so as to form a head portion, a neck portion, a flange and a shaft portion, and the ball portion is struck by a punch from above the head portion, To a position of the upper end of the flange from the shaft portion; Disposing a plurality of divided molds for forming the neck portion on the upper side of the die; A step of hitting the head portion of the ball stud material and the split mold with the punch to form a shape of the neck portion and a shape of the flange; And separating the punch and the split mold from the dice to pull out the ball stud part from the dies. In the method of forming the ball stud for the stabilizer link, it takes a long time to produce by using a mold suitable for the shape, , Noise pollution and punch mold replacement costs are incurred in the factory.

As another conventional technique, there is a method of manufacturing a ball stud which can improve the concentricity between a ball and a stud proposed in Registration Practical Utility Model No. 20-0364024.

The registered utility model inserts the stud 2b of the ball stud 2 into the lower jig 32 of the resistance welder and then fixes the stud 2b using the lower electrode 11 of the bidirectional open chuck structure, In which the ball 2c vacuum-adsorbed 30 is placed on the center of the stud 2b by using the upper electrode 10 and then the ball stud 2 is manufactured by the resistance welding 114. In the stud 2b, The spherical balls 2a are configured to be welded 44 and tempered 46 to provide good weld quality and strength at the welded site so that the temperature of the ball stud is maintained at 350 to 650 占 폚 However, since the quality is determined only by controlling the temperature, there is a problem in that it can not cope with various variables.

Registration Utility Model No. 20-03640224 Korean Patent Registration No. 10-1820514

Therefore, in the present invention, a bolt and an object to be welded are separately prepared, one is a fixed base material and the other is a moving base material, and a current is supplied in a state in which the bolt and the object to be welded are close to each other. The present invention provides a method of manufacturing a power transmission bolt using welding that softens a workpiece to be welded, press-joins the workpiece in a semi-permanent manner, and increases productivity and produces a product of a constant quality.

Further, a protrusion is formed on the jointed end face of the stud welded to the ball, so that the current supplied in the current supply step is concentratedly supplied between the ball and the protrusion, thereby increasing the softening speed of the tissue and uniformizing the softening amount. Another object of the present invention is to provide a method of manufacturing a power transmission bolt using welding capable of producing a product.

The method for manufacturing a bolt for power transmission using welding according to the present invention comprises a raw material preparation step of preparing a ball of a fixed base material and a stud of a moving base material, a fixing step of fixing the prepared ball and stud to the respective jig devices, A current supplying step of flowing a current between the ball and the stud moved close to each other; and a step of fixing one of the ball and the stud, in which the softening is caused by the supplied current, A press-bonding step of moving the other side by pressure bonding, and a discharging step of discharging the press-bonded product.

In the method of manufacturing a power transmitting bolt using welding according to the present invention, bolts and workpieces are prepared separately, one is set as a fixed base material and the other is set as a moving base material so as to supply current A bolt and a welded material are softened by using heat generated by electrical resistance, and a semi-permanent connection is made by press bonding in this state, so that productivity can be enhanced and a product of constant quality can be produced. So that the current supplied in the current supply step is concentratedly supplied between the balls and the protrusions, thereby increasing the softening speed of the tissue and uniformizing the amount of softening, thereby remarkably producing a product of a constant quality have.

1 is a flowchart of a method of manufacturing a ball stud according to the present invention;
2 is a perspective view of a ball stud according to the present invention;
3 is a view showing the entire construction of a method of manufacturing a ball stud according to the present invention
4 is a conceptual view of a ball stud according to the present invention.

The present invention relates to a method of manufacturing a power transmission bolt using welding, more specifically, a method of preparing a bolt and a workpiece separately, one of which is a fixed base material and the other is a moving base material, And a bolt and a workpiece are softened by using the heat generated by the electric resistance, and a semi-permanent connection is made by press bonding in this state, so that a bolt for power transmission .

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

2 is a perspective view of a ball stud according to the present invention, FIG. 3 is an overall view of a method for manufacturing a ball stud according to the present invention, and FIG. 4 is a cross- A method of manufacturing a ball stud according to the present invention is a method of manufacturing a bolt for power transmission using welding that is used for a ball joint of a vehicle in which a ball 6 and a stud 7 are prepared A fixing step S20 of fixing the prepared ball and stud to the respective jig devices, a proximity moving step S30 of approaching the fixed ball and the stud within a predetermined distance, , A current supplying step (S40) of flowing a current between the ball and the stud moved close to each other, a step of fixing one of the ball and the stud which is softened by the supplied current, Step S50 And a discharging step (S 70) of discharging the press-fitted product.

First, a raw material preparation step (S 10) is a step of preparing a spherical ball 6 and a bolt-shaped stud 7 for making a ball stud.

The next fixing step S 20 is a step of seating and fixing the prepared ball 6 and the stud 7 to the respective jig devices attached to the servo press 1. When the ball 6 is used as a fixed base material, The ball 7 is inserted into the inner surface of the fixed clamping jig 5 and is seated and fixed at a uniform position. The stud 7, which is a relatively movable base material, is inserted into the inner surface of the moving clamping jig 8, And is fixed.

Next, the proximal moving step S30 is carried out by moving the stud 7, which is set on the basis of one side of the ball 6, which is the fixed base material seated and fixed to the fixed clamping jig 5, It is close to the interval value of the specified condition, and the proximity distance is about 1 to 3 mm. The automatic close-up system adjusts the distance between the base materials with minimum movement and can change individually, thereby reducing the cycle time and increasing the productivity.

The movable clamping jig 8 attached to one side of the servo press 1 is moved in the left-right direction or the up-down direction with reference to the fixed clamping jig 5 on which the balls 6 of the fixed base material, The distance between the stud 7 of the movable base material and the ball 6 of the fixed base material can be selectively adjusted and changed even if the stud 7 fixed to the movable clamping jig 8 is changed, And the cycle time can be maintained.

The next current supply step S40 is a step for supplying electric current to the two parent materials in which the close movement step S30 has been completed. The current supply step S40 is a step for supplying current to both the balls 6 as the fixed parent material and the stud 7 Heat is generated to cause softening phenomena in both base materials.

Referring to the welding conditions of FIG. 4, when the initial voltage is rapidly increased, the current is allowed to flow, the current is gradually stopped, and then the voltage is gradually increased again. Then, when the voltage is increased by the servo press 1, And the current can be cut off after welding is finished.

Here, designation conditions for softening between the two base materials designate heat generation amount and flash time, and the designated conditions can be individually changed.

In addition, the calorific value can be adjusted by individually adjusting the amount of current flowing between the base materials and the flow time of the current, thereby increasing productivity by appropriately adjusting the amount of melting and melting time of the base material.

In addition, the flash time will be reduced when the same material is used, and it is desirable to give comparatively more flash time when bonding materials of different materials.

The next pressurizing and bonding step (S50) is a step of fixing one of the ball 6 and the stud 7 softened by the supplied current and moving the other one by pressure bonding, The moving clamping jig 8 in which the stud 7 as the moving base material is seated and fixed in the direction of the fixed clamping jig 5 in which the ball 6 as the fixed base material is seated and fixed is moved to the designated condition , The pressing force, the feeding speed and the waiting time can be individually changed according to the specified conditions.

The next discharge step (S70) is a discharging step of discharging the press-bonded product, which is a step of discharging the press-bonded product.

Here, a rapid cooling step (S55) may be added between the press bonding step (S50) and the bead inspecting step (S60).

That is, in the rapid cooling step (S 55), compressed air of 5 to 8 kg / cm ² is supplied for 5 to 10 seconds to the balls and studs to which pressure bonding is applied, thereby rapidly cooling the balls and the stud joint surfaces, It is possible to improve the strength, that is, the shear strength of the joint surface between the two.

Meanwhile, as shown in FIG. 3, the designation condition for each step is individually changed through text control and graphical control through a control program, so that the productivity is high, and uniform quality and data are digitized to prevent a bad recurrence.

2, the stud 7 has a protrusion 7a protruded by a predetermined length on the end face contacting with the ball 6, and the ball 6 and the stud 6a, which are caused by the current supplied by the protrusion 7a, The softening speed of the resin layer 7 is increased and the productivity is improved.

That is, the protrusion 7a protrudes to the central portion of the end face of the stud 7 when the current supply step S40 is performed, so that the flow of the current is concentrated and the temperature of the protrusion 7a rises faster than the ambient, Uniform uniform heat transfer occurs at the outer periphery of the cross section centered on the outer circumferential surface of the stud, so that the softened amount of the stud surface, that is, the entirety of the cross section, becomes uniform.

The protrusion 7a formed on one surface of the stud 7 has a length of 0.5 to 1.5 mm.

 When the length of the protrusion 7a is less than 0.5 mm, the concentration of the current is decreased and the uniform softening due to the protrusion 7a does not occur. When the length exceeds 1.5 mm, the softening speed of the tissue is slowed, The amount of beads supplied while the molten resin 7a melts increases and the shape of the beads increases due to the appearance of the beads at the outer surface of the joint between the balls 6 and the stud 7 so that the bead cutting process may further occur. mm.

Between the pressurizing and bonding step S50 and the discharging step S70 a bead inspecting step S60 for inspecting the beads formed between the ball 6 and the stud 7 by the vision sensor 9 is added The bead detected in the bead inspecting step S60 is quantified as a defective product when the difference between the reference shape and the reference shape is greater than a predetermined value, and in the current supplying step S40, S 60, the amount of current supplied is increased or decreased.

That is, if the bead amount detected in the bead inspecting step S60 is larger than the bead amount of the reference product, the supplied current amount can be lowered, and in the opposite case, the amount of supplied current can be increased.

Also, when the current amount is left as it is, the pressing force by the servo press 1 can be applied by using the bead amount detected in the bead inspecting step (S60) as a variable. That is, by changing the pressing force by the servo press 1, the bead amount can be changed.

By applying the vision sensor 9 as described above, it is possible to perform uniform and stable inspection and collect data on the room temperature, the hardness, the calorific value, the pressing force, the moving speed and the waiting time, And can be analyzed and quantified, and since the specified conditions can be reflected and changed in the control program through the numerical data, it is possible to produce ball stud with uniform quality.

In the above-described embodiments, a method of manufacturing a ball stud using a ball and a stud is mainly described. However, the ball stud can be applied to a power transmitting bolt having various shapes such as hemispheres and polygons instead of a ball.

As a result, in the method for manufacturing a power transmitting bolt using welding according to the present invention, the bolt and the workpiece are prepared separately, one is set as a fixed base material and the other is set as a movable base material, And the welds are softened by using the heat generated by the electrical resistance, and the welded joints are semi-permanently bonded by press bonding in this state, thereby remarkably improving the productivity and producing a product of constant quality. And the current supplied in the current supply step is concentratedly supplied between the balls and the protrusions so as to increase the softening speed of the tissue and keep the amount of softening uniform, It is effective.

S 10. Raw material preparing step S 20. Fixing step
S 30. Proximity movement step S 40. Current supply step
S 50. Pressure bonding step S 60. Bead inspection step
S 70. Discharge phase S 80. Current rise / fall
1. Servo press 2. Inverter
3. Transformer 4. Display device
5. Fixed clamping jig 6. Ball
7. Studs 7a. spin
8. Movement clamp 9. Vision sensor

Claims (4)

A method of manufacturing a power transmitting bolt using welding for a ball joint of a vehicle,
(S 10) for preparing the balls (6) and the studs (7), a fixing step (S 20) for fixing the prepared balls and studs to the respective jig devices, (S30) for moving the ball and the stud in close proximity to each other, a current supplying step (S40) for flowing a current between the ball and the stud moved close to each other, And a discharging step (S 70) of discharging the press-bonded product, wherein the press-bonding step (S 50)
The stud 7 has a protrusion 7a protruded by a predetermined length on the end face in contact with the ball 6. The protrusion 7a serves to soften the ball 6 and the stud 7 by the current supplied by the protrusion 7a, The speed is increased, the productivity is improved,
The length of the protrusion 7a formed on one surface of the stud 7 is between 0.5 and 1.5 mm,
A rapid cooling step (S 55) is added between the press bonding step (S 50) and the bead inspecting step (S 60), wherein the rapid cooling step (S 55) cm < ² > of compressed air for 5 to 10 seconds to rapidly cool the ball and stud contact surfaces, thereby improving the strength of the joint surface between the ball and the stud, that is,
A bead inspection step (S60) for inspecting beads formed between the ball (6) and the stud (7) by the vision sensor (9) is added between the pressurizing and bonding step (S50) The bead detected in the bead inspecting step S60 is quantified as a defective product when the difference is greater than a predetermined value by digitizing the difference between the reference shape and the reference shape, and in the current supplying step S40, Wherein the pressing force of the servo press (1) is changed while keeping the amount of current supplied by using the shape of the bead detected by the servo press (1).
delete delete delete

Images