KR20200083327A - Friction stir welding tool - Google Patents

Abstract

The present invention relates to a friction stir welding tool comprising: a shank unit to perform a reciprocating motion and a rotating motion with respect to a material to be welded; and a pin unit provided with a holder bush to adjust a welding depth of the material to be welded and a coupling protrusion formed on the upper end thereof, and coupled to the shank unit to weld the material to be welded. The shank unit has an upper hollow space and a lower hollow space formed therein. The upper hollow space is formed to insert and screw-couple the holder bush thereinto. The lower hollow space is formed to insert and screw-couple the pin unit thereinto. The holder bush has an adjustment groove formed on the upper end thereof. A length adjustment member is coupled to the adjustment groove to adjust the length of the pin unit. A coupling groove is formed on the lower end of the holder bush to insert the coupling protrusion thereinto to couple the shank unit and the pin unit. Therefore, the length of the pin unit can be easily adjusted in a friction stir welding process.

Description

Friction stir welding tool {FRICTION STIR WELDING TOOL}

In the present invention, by adding a holder bush for facilitating the length adjustment of the pin portion, and forming a thread to convey the holder bush to the inner diameter of the shank portion, to a friction stir welding tool that can be applied to both flat and circular joints. Is about

Friction stir welding is a solid-state joining technique that welds by frictional flow in a material using friction heat. When a non-consumable tool having a thread-like protrusion is rotated at a high speed and inserted into a material to be joined, it is caused by mutual friction between the tool and the material to be joined. Heat is generated, and the material around the tool is softened by frictional heat, and welding of the material to be joined is performed on the principle that the materials on both sides of the joint are forcibly mixed by the plastic flow of the material by stirring of the tool.

In this welding method, since welding is performed with a small amount of heat, the residual stress and the like are excellent in mechanical strength, and since auxiliary materials for welding are not required, such as general welding, unnecessary materials are not generated during the process.

However, in the friction stir welding process, the welding tool rotates at high speed and advances. The material to be plastically deformed by frictional heat receives the advancing pressure of the tool shank portion, and accordingly, the material of the material to be joined is pushed out. (burr).

The burr formed as described above occurs at the surface of the joint, and since the thickness of the joint causes weight reduction of the material to be joined due to the material being pushed out, a material in good condition cannot be obtained.

In addition, in order to efficiently join the material to be joined, the heat of friction due to the rotation of the tool for friction stir welding is rapidly generated, so the temperature of the material to be joined must be rapidly increased so that the rotation speed of the tool for friction stir welding is Differences can occur due to various factors (eg, the shape of the tool).

In addition, in the conventional friction stir welding tool, as shown in FIGS. 1 and 2, the load received by the tool varies according to an offset value in joining dissimilar materials, and when one of the dissimilar materials is steel, has a high lifespan. It is known that it is desirable to apply a three-axis structure without a tilting axis (four-axis structure in case of tilting), which is advantageous for large torque, because expensive materials are required as tools are required, and a large amount of force is required when joining dissimilar materials. have.

In the case of the integrated tool of the pin, shoulder, and shank parts, the material is consumed at the time of manufacture, and when the tool is worn during bonding, it must be disposed of collectively. In the friction stir welding process, the length of the pin should be changed depending on the thickness of the material to be joined. In the case of the integral type, there is a problem that it can be applied only to a single thickness of material.

1. Korean Registered Patent No. 10-1687250 (registered on December 12, 2016) 2. Korean Patent Publication No. 10-2015-0024380 (published on June 6, 2015)

The present invention is to provide a friction stir welding tool in which the length of the pin portion is adjusted as the depth at which the holder bush is inserted into the pin portion is adjusted by using a length adjusting member in order to easily set the friction depth at which the material to be joined rubs. do.

In addition, the present invention is to provide a friction stir welding tool in which the pin portion is provided separately from the shank portion so that the pin portion can be easily replaced, and the pin portion penetrates through the shank portion.

In addition, the present invention provides a friction stir welding tool in which a plurality of threads parallel to the pin portion are formed in order to extend the life of the tool by dispersing the load generated by the material of the material to be joined to each of the plurality of threads. Want to provide

In addition, the present invention, the burr (burr) generated during the welding process is not discharged to the outside so that the weight reduction of the joined material can be suppressed, curved while drawing a gentle arc from the outside of the shank portion shoulder toward the center portion. It is provided with a plurality of burr grooves in the form of a whirlwind from the outside to the inner center, which increases the contact area with the material to be joined and induces a higher pressure to be applied to the protrusion surface where no burr groove is formed in the shoulder of the shank portion. It is intended to provide a friction stir welding tool.

The purpose of the embodiments of the present invention is not limited to the above-mentioned purpose, and other objects not mentioned will be clearly understood by those skilled in the art from the following description. .

According to an embodiment of the present invention, a shank portion that reciprocates and rotates with respect to the to-be-joined material, a holder bush for adjusting the welding depth of the to-be-joined material is provided, an engaging projection is formed at the upper end, and coupled to the shank portion It includes a pin portion for welding the material to be joined, the shank portion, the inside is formed of an upper hollow portion and a lower hollow portion, the upper hollow portion is formed to be screwed by inserting the holder bush, the lower hollow portion, the The pin portion is inserted to be screwed, and the holder bush is formed with an adjusting groove at the upper end, a length adjusting member is coupled to the adjusting groove, the length of the pin portion is adjusted, and an engaging groove is formed at the lower end to engage the Protrusions may be inserted to provide a friction stir welding tool in which the shank portion and the pin portion are coupled.

In addition, according to an embodiment of the present invention, the pin portion includes a friction end generating friction material and friction heat at a lower end, a load reducing end having a plurality of threads removed perpendicular to the friction end, and a material to be joined under the friction end It can provide a friction stir welding tool comprising a contact end in contact with.

In addition, according to an embodiment of the present invention, the shank portion is formed on the burr groove formed in three so as not to cross each other in a whirlwind form from the outside to the bottom surface, and is formed on the upper side of the shank portion, the shank from the motor It is possible to provide a friction stir welding tool comprising a key groove that transmits a rotational force to a negative.

In addition, according to an embodiment of the present invention, the burr inlet groove, the center portion can provide a friction stir welding tool having a width of 1mm to 2mm.

In addition, according to an embodiment of the present invention, the burr-in groove can provide a friction stir welding tool having a ratio of 1:1.5 to 1:5 in the width and depth in the central portion.

According to the present invention, the length of the pin portion is adjusted as the depth at which the holder bush is inserted and coupled to the pin portion using the length adjusting member is adjusted, so that the frictional depth at which the material to be joined rubs can be easily set.

In addition, according to the present invention, as the pin portion is provided to be coupled through the shank portion, the pin portion can be easily replaced.

In addition, the present invention can increase the frictional heat generated between the tool and the material to be joined in the friction stir welding process and suppress the occurrence of burrs that may occur during the process.

In addition, the present invention is to form a load reduction stage in which a portion of the thread is removed on the side surface of the pin portion, thereby suppressing the load applied to the thread to increase the rotational speed of the pin portion, and the large frictional heat generated by the increased rotational speed By rapidly increasing the temperature of the material to be joined to the temperature at which the material can be softened, the process time of friction stir welding can be shortened.

In addition, the present invention is provided with a plurality of burr indentation grooves in which burrs of the material to be joined can be inserted into the shoulder of the shank part, due to fluctuations in the weight of the material to be joined as it is discharged outside the burr that may occur during the process of friction stir welding process. It is possible to prevent the welding efficiency from being reduced.

1 is a view illustrating a friction stir welding tool according to an embodiment of the present invention.
2 is a view for explaining a friction stir welding tool according to an embodiment of the present invention.
3A to 3B are views for explaining a friction stir welding tool according to an embodiment of the present invention.
4A to 4E are views for explaining the shank portion and the pin portion of the friction stir welding tool according to the embodiment of the present invention.

Advantages and features of the embodiments of the present invention, and methods for achieving them will be made clear by referring to embodiments described below in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only the embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention pertains. It is provided to completely inform the person having the scope of the invention, and the present invention is only defined by the scope of the claims. The same reference numerals refer to the same components throughout the specification.

In describing embodiments of the present invention, when it is determined that a detailed description of known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, terms to be described later are terms defined in consideration of functions in an embodiment of the present invention, which may vary according to a user's or operator's intention or practice. Therefore, the definition should be made based on the contents throughout this specification.

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

1 is a view illustrating a friction stir welding tool according to an embodiment of the present invention, FIG. 2 is a view for explaining a friction stir welding tool according to an embodiment of the present invention, and FIGS. 3A to 3B are embodiments of the present invention It is a view for explaining a friction stir welding tool according to an example, and FIGS. 4A to 4E are views for explaining a shank portion and a pin portion of the friction stir welding tool according to an embodiment of the present invention.

1 to 4E, a friction stir welding tool according to an embodiment of the present invention may include a shank portion 110, a pin portion 120, and the like.

The shank portion 110 is a reciprocating and rotational movement with respect to the surface of the material to be joined, the upper portion of which is coupled to a motor provided on the outside, and the lower portion of the pin portion 120 is combined with the pin portion 120 to receive the rotational force transmitted from the motor. ), and may include a bur-in groove 111, a key groove 112, and the like.

Accordingly, the shank portion 110 may move horizontally while pressing and rotating the material to be joined, and when the material to be joined is placed vertically, the shank portion 110 may move vertically while pressing and rotating the material to be joined. .

As the shank portion 110 is formed by being hollow inside, the upper hollow portion is formed to be shaped to correspond to the holder bush 121 so that the holder bush 121 is inserted, and a thread 110a is formed inside the upper hollow part. The inserted holder bush 121 is combined.

In addition, the lower hollow portion is formed to conform to the pin portion so that the pin portion 120 is inserted, a thread 110b is formed inside the lower hollow portion and is coupled to the thread 120a formed on the side of the inserted pin portion 120 do.

Particularly, the width (or diameter) of the lower hollow portion is formed to be narrower than the width (or diameter) of the upper hollow portion, so that the holder bush 121 inserted into the upper hollow portion is inserted by a predetermined depth, and then prevents downward entry Can be.

Meanwhile, a plurality of bur-in grooves 111 are formed on the lower surface of the shank portion 110 so as not to cross each other in a whirlwind form from the outside to the inside.

Here, the bur inlet groove 111 may be provided on the lower surface of the shank portion 110 to which the shank portion 110 and the pin portion 120 are fastened.

That is, the burr indentation groove 111 is curved in a horizontal cross-section on a lower surface of the shank portion 110 by drawing a gentle arc from the outer side to the inner side, which is the central portion, and a burr groove in the form of a whirlwind from the outer side toward the inner center. A plurality of 111 may be formed so as not to cross each other.

For example, if three burr indentations 111 are provided, they may be arranged at 120 degree intervals. Such a tornado shape may be formed such that the width (W) and depth (H) of the central portion have a relatively smaller width (W) and depth (H) than both ends (ie, both ends have a pointed shape).

Here, the material of the material to be joined is softened due to frictional heat generated between the pin portion 120 and the material to be joined during the friction stir welding process, and the softened material is external to the pin portion 120 due to the rotational movement of the pin portion 120. By being pushed out, damage is generated on the surface or inside of the material to be joined. When the burr inlet groove 111 is formed on the lower surface of the shank portion 110 as described above, the burrs generated are each burr. It is possible to prevent damage to the material to be joined by entering the inside without being pushed outward along the inlet groove 111.

In addition, when the burr inlet groove 111 is formed, the rotational force of the motor is further induced by applying a higher pressure to the protruding surface where the burr inlet groove 111 is not formed in the lower surface of the shank portion 110 It is transmitted largely and can contact with the material to be joined and generate large frictional heat.

In addition, when the burr inlet groove 111 is formed, since the friction area corresponding to the burr inlet groove 111 may be increased, as the area to rub the material to be joined is larger than when the groove is not formed, the larger It can generate friction heat.

Here, the burr inlet groove 111 may have a width W of the central portion of 1 mm to 2 mm, and the depth H of the central portion of each burr inlet groove 111 is approximately 1 to the width W. It may be formed to have a depth (H) of 1.5 to 1:3.5, the width (W) and depth (H) of the burr inlet groove (111) toward the inside from the outer side of the lower surface of the shank portion (110) to be smaller Can be formed.

When the ratio of the width and depth in the central portion of the burr inlet groove 111 is less than 1:1.5, the material flow phenomenon is reduced and the flow rate is not smooth, and due to the formation of the burr inlet groove 111, the area of friction with the material to be joined The effect of generating large friction heat can be reduced by widening. On the other hand, when the ratio of the width and depth in the central portion of the burr inlet groove 111 exceeds 1:3.5, the softened material to be joined into the burr inlet groove 111 is not separated and cannot be separated from the burr inlet groove 111 As it remains, there is a concern that stress is generated by the remaining material to be joined, which may weaken the stiffness of the buried groove 111, and also, the depth of the buried groove 111 is reduced by the remaining material to be joined. Accordingly, burrs generated during the friction stir welding process may not be effectively removed.

The key groove 112 is located at the upper end of the shank portion 110, and a part of the upper side of the shank portion 110 is formed in a flat surface, thereby firmly and stably supporting the shank portion 110 and the motor, thereby making the shank portion 110 ) Rotates, it is possible to continuously maintain the rotational force transmitted from the motor to the shank portion 110.

The pin portion 120 is coupled to the shank portion 110 to weld the material to be joined, and serves to weld the material to be welded by generating frictional heat by contacting and rubbing with the material to be joined, the holder bush 121 and the friction end It may include a 122, the load reducing end 123, the contact end 124, and the like.

Here, the pin portion 120 may be coupled through the hollow interior of the shank portion 110. That is, since it can be inserted into the upper surface of the shank portion 110 and penetrates through the shank portion 110 and protrudes to the lower surface, during the friction stir welding process, the pin portion 120 in which wear due to friction is concentrated is easily separated. Can be replaced.

In addition, the welding depth of the material to be joined can be adjusted by the holder bush 121 of the pin part 120. In the holder bush 121, an adjustment groove 121a is formed at an upper end, and a length is adjusted in the adjustment groove 121a. A member (not shown) is coupled to adjust the length of the pin portion 120, and a coupling groove 121b is formed at the lower end, so that the pin portion 120 can be coupled through the coupling groove 121b.

In addition, the holder bush 121 is formed on the side of the holder bush 121 along the thread 110a formed on the inner surface of the upper hollow portion of the shank portion 110, the holder bush 121 is inside the shank portion 110 It can be inserted and combined.

The length adjusting member (not shown) is inserted into the adjusting groove 121a of the holder bush 121 to adjust the length of the pin portion 120 that generates frictional heat by contacting the material to be joined, and can be automatically or manually adjusted. .

That is, when a motor or the like is coupled to the length adjusting member (not shown) and driven, as the friction stir welding operation is performed and the motor that separately operates the length adjusting member (not shown) is driven, the pin portion 120 is simultaneously with the welding process. ) The length of the pin can be adjusted, and when the length adjusting member (not shown) is provided as a work tool such as a wrench, the length of the pin part 120 may be adjusted before or during the friction stir welding operation. have.

In addition, the pin portion 120 is provided with a thread () on the side of the lower portion is coupled to the shank portion 110, a friction end 122 is formed at the lower end to generate the material to be joined and friction heat, the friction end 122 A load reduction end 123 in which a plurality of threads are vertically removed is provided, and a contact end 124 in contact with the material to be joined is provided below the friction end 122.

The friction end 122 is located on the side of the pin portion 120, can generate frictional heat by contacting the material to be joined, and is provided with a plurality of threads 122a horizontally parallel to the bottom direction from the top of the pin portion 120 Can be.

Here, the horizontally parallel threads 122a may soften the object to be welded by generating frictional heat by direct contact or surface contact with the material to be joined. In the case of the helical threads 122a, the tool enters the material to be joined. Since the speed is relatively increased, since the tool can enter without the material to be softened sufficiently, there is a problem in that the bonding performance is deteriorated, according to an embodiment of the present invention, the plurality of threads 122a are horizontally Can be formed.

Due to this, the entry speed of the tool into the material to be joined can be reduced, and sufficient frictional heat can be generated to soften the material to be joined.

In addition, the material of the softened material to be joined may accumulate in the groove of the thread 122a while rising opposite to the entry direction of the pin part 120. In the case of the spiral thread 122a, the entire thread 122a is connected. Therefore, the entire thread 122a can be loaded by the accumulated material of the material to be joined.

On the other hand, in the case of horizontally parallel threads 122a, the material of the softened material to be joined may accumulate in the grooves of each thread 122a according to the softened position, and this is caused by the accumulated material to be joined. Since the load can act on each of the threads 122a, according to an embodiment of the present invention, a plurality of threads 122a can be formed horizontally.

In addition, the load reducing end 123 is a thread 122a that is removed perpendicular to the friction end 122, and may be provided in a plurality with a constant angular spacing.

Here, the utility of friction stir welding generates the frictional heat generated by contact with the material to be joined by rotation of the pin portion 120 at a high speed and increases the temperature to a temperature at which the material to be softened can be softened. Depending on whether it is possible, if there is a thread 123a in the entire friction end 122, the friction area is large, and thus a larger amount of friction heat can be generated, but the load added to the thread 122a according to the width of the friction area By increasing, it is possible to reduce the rotational speed of the pin portion 120.

On the other hand, when the flat surface is formed by removing the thread 122a of a portion of the friction end 122, the load applied to the thread 122a may be reduced, and the load added to the thread 122a may be reduced. When the rotational speed of the pin 120 increases, the frictional heat generated by contact with the material to be joined increases and the speed at which the material to be reached reaches a temperature that can be softened can also be effectively increased.

The ratio between one width (a1, a2, a3) of the load reduction stage 123 and the circumferential length (b) of the pin portion 120 may be formed from 1:10 to 1:15, and the load reduction The number of stages 123 may be provided in two to four. In addition, when the plurality of load reduction stages 123 are not biased or formed at a uniform angle on one side, the vertical axis of the center of gravity of the pin portion 120 does not match the rotation axis when the pin portion 120 is rotated. Because (ie, eccentricity may occur), when the pin 120 is rotated, the pin 120 may vibrate and rotate. Therefore, the plurality of load reduction stages 123 may be arranged with uniform angular spacing.

For example, when three load reduction stages 123 are provided, they may be disposed at 120 degree intervals.

The contact end 124 is located at the bottom of the pin portion 120 so that the tool for friction stir welding can be inserted into the material to be joined while rotating. The shape of the contact end 124 may be V- or U-shaped, but may be provided in a U-shape to reduce the wear rate of the contact end 124 due to direct contact with the material to be joined.

In the above description, various embodiments of the present invention have been presented and described, but the present invention is not necessarily limited thereto, and a person having ordinary knowledge in the technical field to which the present invention pertains may depart from the technical spirit of the present invention. It will be readily appreciated that branch substitution, modification and modification are possible.

110: shank portion
111: Burr entry groove
112: keyway
120: pin
121: holder bush
122: friction stage
123: load reduction stage
124: contact terminal

Claims (5)

Shank portion for reciprocating and rotating motion with respect to the material to be joined,
A holder bush for adjusting the welding depth of the material to be joined is provided, a coupling protrusion is formed at the upper end, and a pin portion is coupled to the shank to weld the material to be joined,
The shank portion, the inside is formed of an upper hollow portion and a lower hollow portion, the upper hollow portion is formed to be screwed by inserting the holder bush, the lower hollow portion is formed to be screwed by inserting the pin portion,
In the holder bush, an adjusting groove is formed at an upper end, a length adjusting member is coupled to the adjusting groove, the length of the pin portion is adjusted, and an engaging groove is formed at a lower end to insert the engaging projection so that the shank portion and the pin portion are Combined
Friction stir welding tool.
According to claim 1,
The pin portion,
A friction end generating friction heat with the material to be joined at the lower end,
A load reducing end having a plurality of threads removed perpendicular to the friction end,
A contact end in contact with the material to be joined below the friction end
Friction stir welding tool comprising a.
According to claim 2,
The shank portion,
A burr groove formed in three so as not to cross each other in a whirlwind form from the outside to the inside on the bottom surface
It is formed on the upper side of the shank portion, the key groove for transmitting the rotational force from the motor to the shank portion
Friction stir welding tool comprising a.
The method of claim 3,
The bur-in groove,
Friction stir welding tool with a central portion having a width of 1 mm to 2 mm.
The method of claim 4,
The bur-in groove,
A friction stir welding tool having a ratio of 1:1.5 to 1:3.5 in the width and depth in the central portion.

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