JP2011230160A - Tool for friction stir welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tool for friction stir welding, which can have an extended life by preventing uneven wear of a peripheral region of a probe.SOLUTION: The tool 10 for friction stir welding includes: a circular shoulder section 20; and the probe 14 which has a smaller diameter than the shoulder section 20 and is provided on the center axis of the shoulder section 20. The shoulder section 20 has: a flat section 22 which surrounds the probe 14; a plurality of protrusion sections 24 which are formed at circumferential intervals and extend in an arc from the flat section 22 toward the outer periphery of the shoulder section 20; and a plurality of recessed sections 26 which are formed between the plurality of protrusion sections 24.

Description

  The present invention relates to a friction stir welding tool having a circular shoulder portion and a probe provided on the central axis of the shoulder portion.

  In the friction stir welding method, a cylindrical rotating tool (friction stir welding tool) with a probe (protrusion) at the tip is pressed with a strong force while rotating, and the probe is applied to the joint of the member (base material) to be joined. Is a joining method in which a plurality of members are integrated by softening the base material by generating frictional heat and softening the periphery of the joint by the rotational force of the tool and kneading and mixing (for example, See Patent Document 1 below).

  The rotary tool described in Patent Document 1 has a circular shoulder portion and a probe having a smaller diameter than the shoulder portion, and the shoulder portion has an arc shape from the outer peripheral portion of the probe to the outer edge portion of the shoulder portion. There is a groove extending to the surface. When friction stir welding is performed using a rotary tool provided with such a groove, a part (material) of the joining member flows so as to be wound from the outer peripheral side to the center side of the rotary tool by the action of the arc-shaped groove. . That is, the material is collected on the center side of the rotary tool.

JP 2003-39181 A

  By the way, when performing the friction stir welding of a relatively hard material such as a steel-based material, for example, when the rotary tool described in Patent Document 1 is used, the center probe becomes a wall and the temperature is increased by frictional heat. Due to the high pressure of the material, the amount of wear at the peripheral portion of the probe is larger than that at other portions, and as a result, a donut-shaped wear portion is formed at the peripheral portion of the probe. That is, uneven wear occurs. For this reason, the surface roughness in a shoulder part becomes non-uniform | heterogenous. This uneven surface roughness contributes to shortening the life of the rotary tool.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a friction stir welding tool capable of extending the life by preventing uneven wear around the probe.

  In order to solve the above-mentioned problems, the present invention is a friction stir welding tool, comprising: a circular shoulder portion; a probe formed on a smaller diameter than the shoulder portion and provided on the central axis of the shoulder portion; The shoulder portion includes a flat portion surrounding the probe, and a plurality of convex portions formed at intervals in the circumferential direction and extending in an arc from the flat portion toward the outer peripheral side of the shoulder portion. And a plurality of concave portions formed between the plurality of convex portions.

  According to said structure, since the flat part is provided in the shoulder part, generation | occurrence | production of the partial wear by the pressure becoming high too much in the peripheral part of a probe is suppressed effectively. Further, by suppressing the occurrence of uneven wear, the surface roughness of the flat portion and other portions in the shoulder portion becomes uniform, and the conditions regarding wear and deterioration are the same. As a result, the life of the joining tool can be extended.

  The convex portion may extend within a range that does not go around the flat portion.

  According to said structure, since the width | variety of a convex part does not become narrow too much and the width | variety of a convex part is ensured moderately, the lifetime improvement of the tool for joining can be aimed at.

  The concave portion may be set wider than the convex portion.

  According to the above configuration, by widening the concave portion, the material can be effectively guided to the flat portion side, and the material that has once flowed out of the flat portion easily returns, so the material on the center side of the shoulder portion. Can be collected effectively. Thereby, it can prevent that the location in which the joining bead was formed is dented with respect to joining material, and can improve external appearance quality and joining quality. Further, since the convex portion is smaller than the concave portion, the pressing force against the joining member does not become excessively large, and therefore, an appropriate pressing force is applied to the joining member, the plastic flow of the material is promoted, and good joining is achieved. Can be implemented.

  The convex portion has an inner end side portion extending along a peripheral direction of the probe at an end portion on the probe side, and an inner peripheral portion constituting an inner peripheral side of the curved portion of the convex portion, The corner portion at the location where the inner end side portion and the inner peripheral portion are connected may be formed in a substantially arc shape.

  According to said structure, since the corner part of a convex part is formed in the substantially circular arc shape, the material gathered together by the recessed part can be guide | induced smoothly to a flat part, and this makes material more effective. They can be gathered together, the formation of the concave shape of the joining bead can be suitably prevented, and the appearance quality can be further improved.

  According to the friction stir welding tool of the present invention, uneven wear at the periphery of the probe can be prevented, and the tool life can be extended.

It is a partially omitted perspective view of the friction stir welding tool according to an embodiment of the present invention. 1 is a partially omitted side view of a friction stir welding tool according to an embodiment of the present invention. It is sectional drawing in the III-III line in FIG. It is a perspective view which shows the state which is implementing friction stir welding.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a friction stir welding tool according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a partially omitted perspective view of a friction stir welding tool 10 (hereinafter referred to as a welding tool 10) according to an embodiment of the present invention. FIG. 2 is a partially omitted side view of the welding tool 10. In the accompanying drawings, the axial direction of the welding tool 10 is indicated by an arrow A, and in particular, the distal end side is indicated by A1 and the proximal end side is indicated by A2. Further, the rotation direction of the welding tool 10 when the friction stir welding is performed using the welding tool 10 is indicated by an arrow R.

  As shown in FIGS. 1 and 2, the joining tool 10 is formed with a cylindrical tool body 12 and a smaller diameter than the tool body 12, and the tool body 12 on the axis (center line) C of the tool body 12. And a probe 14 protruding from the distal end surface. The tool body 12 of the illustrated example has a body portion 16 and a head portion 18 having a diameter larger than that of the body portion 16. The front end surface of the head portion 18 is configured as a shoulder portion 20.

  The probe 14 is a portion that protrudes to the most distal end side in the welding tool 10 and is formed in a substantially truncated cone shape having a low height in the illustrated example. Note that the probe 14 may be formed in a long pin shape in the axial direction depending on various conditions such as the thickness of the joining member to be joined.

  The shoulder portion 20 includes a flat portion 22 that surrounds the probe 14, and a plurality of convex portions 24 and concave portions 26 that are provided on the radially outer side of the flat portion 22.

  The position (height) in the axial direction of the flat portion 22 is closer to the proximal end than that of the probe 14. The flat portion 22 extends radially outward from the base portion of the probe 14 and extends in a circular ring shape so as to make a complete round around the probe 14. In the illustrated example, the flat portion 22 is slightly inclined so as to be closer to the base end side (A2 direction) toward the outer side in the radial direction, but may be formed to be substantially perpendicular to the axial direction. . The flat portion 22 may be provided in a range where wear occurs when the convex portion 24 is present up to the position of the flat portion 22. The details of the method for setting the range in which the flat portion 22 is provided will be described later.

  Each convex portion 24 is formed around the flat portion 22 at intervals in the circumferential direction, and extends from the flat portion 22 toward the outer peripheral side of the shoulder portion 20 so as to draw an arc. Specifically, the convex part 24 is curving so that it may approach the rotation direction R side of the tool 10 for joining as it goes to a radial direction outer side. In the present embodiment, the convex portion 24 is not spiral, that is, extends in a range that does not go around the flat portion 22. In the illustrated example, the convex portions 24 are arranged at four locations around the flat portion 22 at equal intervals, but the number of locations where the convex portions 24 are provided is not limited to four, and may be two, three, or five or more. May be.

  The convex portion 24 is connected to the outer peripheral portion of the flat portion 22 at the radially inner end thereof, is curved and extends outward in the radial direction, and the radially outer end reaches the outer peripheral edge portion of the shoulder portion 20. . The radially inner end of the convex portion 24 is separated from the outer peripheral portion of the probe 14 by the amount of the flat portion 22.

  In the illustrated example, the width W of the convex portion 24 is substantially constant over the extending direction of the convex portion 24, but it may be increased as it goes outward in the radial direction, or as it goes outward in the radial direction. It may be small.

  The convex portion 24 has an inner end side portion 28 extending along the circumferential direction of the probe 14 at an end portion on the probe 14 side, and an inner peripheral portion 30 constituting a side on the inner peripheral side of the curved portion of the convex portion 24. The outer peripheral portion 32 constituting the side of the outer peripheral side of the curvature of the convex portion 24. A corner portion 34 at a location where the outer peripheral portion 32 and the inner end side portion 28 are connected on the center side of the shoulder portion 20 is formed in an acute angle shape. On the other hand, the corner portion 36 at the location where the inner end side portion 28 and the inner peripheral portion 30 are connected on the center side of the shoulder portion 20 is formed in a substantially arc shape. In other words, corners 36 are deleted and provided with R (roundness). Further, a minute R is provided by chamfering on the ridge line portion other than the corner portion 36 in each convex portion 24. The minute R may be smaller than R at the corner 36. By providing such a minute R, an increase in the amount of wear at that portion can be suppressed. Note that not only the corner 36 but also the corner 34 may be formed in a substantially arc shape.

  3 is a cross-sectional view taken along line III-III in FIG. As shown in FIG. 3, when the surface of the convex portion 24 is traced from the center side of the shoulder portion 20 to the outer peripheral side, the flat portion 22 approaches the A1 direction side from the outer peripheral portion of the flat portion 22 toward the outer side in the radial direction. It reaches the apex 24a located on the more distal end side, and inclines so as to approach the A2 direction side from the apex 24a to reach the outer peripheral edge of the shoulder portion 20. Thus, the convex portion 24 does not exist in a plane perpendicular to the axis C (center line) of the welding tool 10, but as a whole, is formed so as to rise in the A1 direction as it approaches the axis C side. ing.

  In the illustrated example, the size and shape of each convex portion 24 are the same, but part or all of the size or shape may be varied as necessary.

  As shown in FIGS. 1 and 2, each concave portion 26 is formed around the flat portion 22 with a space in the circumferential direction between the convex portions 24, and extends from the flat portion 22 toward the outer peripheral side of the shoulder portion 20. It extends to draw an arc. The concave portion 26 is connected to the outer peripheral portion of the flat portion 22 at the inner end in the radial direction, extends curvedly in the R direction toward the outer side in the radial direction, and the outer end in the radial direction reaches the outer peripheral portion of the shoulder portion 20. ing.

  The concave portion 26 is formed so that the width in the circumferential direction becomes wider toward the outer side in the radial direction. In the present embodiment, as shown in FIG. 1, the concave portion 26 is formed wider (larger) than the convex portion 24. Of course, the total area of the plurality of concave portions 26 is larger than the total area of the plurality of convex portions 24. In the illustrated example, the size and shape of each recess 26 are the same, but some or all of the size or shape may be varied as necessary.

  As shown in FIG. 3, when the surface of the concave portion 26 is traced from the center side of the shoulder portion 20 to the outer peripheral side, it approaches the base end side (A2 direction side) from the outer peripheral portion of the flat portion 22 toward the outer side in the radial direction. And reaches the outer peripheral edge of the shoulder 20. Thus, the recess 26 does not exist in a plane perpendicular to the axis C (center line) of the welding tool 10, but as a whole, is formed so as to rise in the A1 direction as it approaches the axis C side. Yes.

  The joining tool 10 according to an embodiment of the present invention is basically configured as described above, and the operation and effect thereof will be described below.

  In order to frictionally stir the joining members 40 and 42 using the joining tool 10, as shown in FIG. 4, the joining members 40 and 42 are abutted and positioned at the abutting portion, and driving of a rotational drive source (not shown) is performed. Under the action, the welding tool 10 is lowered while rotating in the R direction around the axis C, and the probe 14 is pressed against the material surface on the abutting portion 44. Thereby, frictional heat is generated by friction between the welding tool 10 and the bonding member, and the material is softened by this heat. Since the joining tool 10 is pressed against the material with a predetermined pressing force, it is inserted into the softened material, and finally the probe 14 is completely buried in the material, and the shoulder portion 20 is the surface of the member. It will be in the state which touched.

  The softened material of the joining members 40 and 42 flows so as to be wound from the outer peripheral side of the shoulder portion 20 to the center side by the action of the arc-shaped convex portion 24. That is, the material is collected on the center side of the welding tool 10 and stirred around the probe 14. In this case, since the concave portion 26 is wider than the convex portion 24, the material can be easily gathered and the material can be efficiently guided to the center side of the shoulder portion 20. Further, in the case of the welding tool 10 according to the present embodiment, since the corner portion 36 (see FIG. 1) of the convex portion 24 is formed in a substantially arc shape, the material gathered by the concave portion 26 is the flat portion 22. Smoothly guided to the side.

  In this case, since the flat portion 22 provided around the probe 14 functions as a portion for escaping the material, wear does not concentrate on the flat portion 22. That is, when a convex portion exists instead of the flat portion 22 on the outer peripheral portion of the probe 14 as in a conventional tool, the high temperature and high pressure material concentrates on the convex portion, so that the convex portion Wears more than other parts, causing uneven wear. On the other hand, in the welding tool 10 according to the present embodiment, there is no portion where uneven wear occurs in the first place, and since the material is appropriately released by the flat portion 22, the pressure at the flat portion 22 is large. It will never be too much. Thereby, generation | occurrence | production of uneven wear is suppressed effectively.

  The softened material around the probe 14 is plastically flowed and agitated by being dragged by the rotation of the welding tool 10. Then, the joining members 40 and 42 are friction stir welded and integrated by moving the joining tool 10 in the arrow B direction along the abutting portion while maintaining the rotation and pressurization of the joining tool 10. . A joining bead 46 is formed at a location where the joining members 40 and 42 are friction stir welded.

  As described above, according to the welding tool 10, since the flat portion 22 is provided on the shoulder portion 20, the occurrence of uneven wear due to excessive pressure around the probe 14 is effectively suppressed. Is done. Further, by suppressing the occurrence of uneven wear, the surface roughness of the flat portion 22 and other portions in the shoulder portion 20 becomes uniform, and the conditions regarding wear and deterioration are the same. As a result, the life of the welding tool 10 can be extended.

  Here, the range in which the flat portion 22 is provided will be described. The inventor of the present application is directed to an experimental joining tool in which a convex portion is formed at a position corresponding to the flat portion 22, and includes a range in which ring-shaped wear occurs (wear range) and whether or not a bonding failure occurs. I investigated the relationship. As a result, when the ratio of the area of the shoulder portion of the portion in contact with the joining member to the total contact area (area of the portion in which the joining tool and the joining member are in contact) is less than 40%, the material by the shoulder portion It was confirmed that the gathering of the particles was insufficient, and that poor bonding was likely to occur.

  Therefore, in the welding tool 10, the flat portion 22 is provided in a range where A1 × 0.4 ≦ A2 when the total contact area is A1 and the area of the shoulder portion 20 in contact with the bonding member is A2. It is preferable to set so as to satisfy. Thereby, generation | occurrence | production of the joining defect resulting from the lack of the area of the shoulder part 20 can be prevented effectively.

  Further, according to the welding tool 10 according to the present embodiment, the convex portion 24 extends in a range that does not go around the flat portion 22 (is not spiral), so that the welding tool 10 lifespan can be improved. That is, when the convex portion 24 is formed in a spiral shape, the width of the convex portion 24 is narrowed, which may affect the life. However, as in the welding tool 10 according to the present embodiment, the convex portion 24 If the range in which the portion 24 is provided (extended range) is a range that does not go around the flat portion 22, the width of the convex portion 24 is not excessively narrowed, and the width of the convex portion 24 is ensured appropriately. The life of the tool 10 can be improved.

  In addition, according to the bonding tool 10 according to the present embodiment, since the concave portion 26 is formed wider than the convex portion 24, it is easy to gather materials. In other words, the material can be effectively guided to the flat portion 22 side by the wide concave portion 26, and the material that has once flowed out of the flat portion 22 easily returns, so that the material is effectively applied to the center side of the shoulder portion 20. Can be collected. Thereby, it can prevent that the location in which the joining bead 46 was formed was recessed with respect to joining material. That is, when a conventional joining tool is used, the place where the joining bead is formed may be recessed with respect to the joining material. However, according to the joining tool 10 according to the present embodiment, the material is effective. Therefore, it is possible to prevent the formation of the concave shape of the joining bead 46 and improve the appearance quality and the joining quality.

  Furthermore, according to the welding tool 10 according to the present embodiment, the corner portion 36 (see FIG. 1) of the convex portion 24 is formed in a substantially arc shape, and therefore the material gathered by the concave portion 26 is collected in the flat portion 22. Accordingly, the materials can be gathered more effectively, the formation of the concave shape of the joint bead 46 can be suitably prevented, and the appearance quality can be further improved.

  Furthermore, according to the welding tool 10 according to the present embodiment, since the convex portion 24 is smaller than the concave portion 26, the pressing force against the joining members 40 and 42 does not become too large. For this reason, an appropriate pressing force is applied to the joining members 40 and 42, the plastic flow of the material is promoted, and good joining can be performed.

  In the above description, the present invention has been described with reference to preferred embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. Needless to say.

DESCRIPTION OF SYMBOLS 10 ... Tool for friction stir welding 14 ... Probe 20 ... Shoulder part 22 ... Flat part 24 ... Convex part 26 ... Concave part 28 ... Inner edge part 30 ... Inner peripheral part 36 ... Corner part

Claims (4)

A friction stir welding tool,
A circular shoulder,
A probe having a smaller diameter than the shoulder portion and provided on the central axis of the shoulder portion;
The shoulder portion is
A flat portion surrounding the probe;
A plurality of convex portions formed at intervals in the circumferential direction and extending so as to draw an arc from the flat portion toward the outer peripheral side of the shoulder portion;
Having a plurality of recesses formed between the plurality of protrusions,
A friction stir welding tool characterized by that. In the friction stir welding tool according to claim 1,
The convex portion extends in a range that does not go around the flat portion.
A friction stir welding tool characterized by that. The friction stir welding tool according to claim 1 or 2,
The concave portion is wider than the convex portion,
A friction stir welding tool characterized by that. In the friction stir welding tool according to any one of claims 1 to 3,
The convex portion has an inner end side portion extending along a peripheral direction of the probe at an end portion on the probe side, and an inner peripheral portion constituting an inner peripheral side of the curved portion of the convex portion,
A corner portion at a location where the inner end side portion and the inner peripheral portion are connected is formed in a substantially arc shape,
A friction stir welding tool characterized by that.

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