Friction stir spot welding tool and method of use

Abstract

This invention provides a friction stir point welding tool that prevents oil leakage from the base of the tool even when the tool's axis is tilted from the vertical. [Solution] Tool 1 comprises a pin 11 and a shoulder 12 into which the pin 11 is inserted. The pin 11 is inserted into the hollow portion 12B of the shoulder 12 with the pin tip 111 inserted into the shoulder tip 121 and the pin base 112 inserted into the shoulder base 122. This creates a gap C between the outer surface of the pin 11 and the inner surface of the shoulder 12. At least one of the outer surface 112a of the pin base 112 and the inner surface 122a of the shoulder base 122 is formed of a sintered cemented carbide.

Description

Technical Field

[0001] The present disclosure relates to a friction stir spot welding tool having a pin and a shoulder, and a method of using the same.

Background Art

[0002] As a method of joining two or more members made of metal members, fiber reinforced thermoplastic resin members, etc. by overlapping them, joining using friction stir is known. For friction stir joining, a friction stir spot welding tool having a pin and a shoulder having a hollow portion for accommodating the pin may be used. For example, in the shoulder-first process, while rotating the shoulder and protruding it into the overlapping portion of the members, the pin is retracted to accommodate the material overflowing due to the press-fitting.

[0003] Since a part of the tool is press-fitted into the joining target member while rotating, a part separated from the joining target member during tool press-fitting may adhere and be held inside the tool. As the number of joining points increases, the amount of the separated matter held from the joining target member also increases, and finally, it adheres to the pin surface and hinders the operation of the tool.

[0004] In the tool described in Patent Document 1, an oil agent is filled in the gap formed between the outer peripheral surface of the pin and the inner peripheral surface of the shoulder. The filled oil agent suppresses the adhesion of the separated matter from the joining target member that has entered the gap between the pin and the shoulder of the tool. Further, due to the lubricating action between the pin and the shoulder by the oil agent, the load on the tool during friction stir joining is reduced.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] When performing friction stir point welding using the above tool, if the two members to be joined are stacked vertically, that is, stacked vertically, the joining operation can be performed with the tip of the tool pointed straight down. However, if the two members to be joined are stacked at an angle relative to the vertical, it is necessary to tilt the axis of the tool from the vertical and point the tip of the tool towards the members to be joined. For example, the axis of the tool may be horizontal, or the tool may be tilted so that the tip points diagonally upward or straight up. In this case, there is a risk that the lubricant inside the gap may leak from the base of the tool.

[0007] This disclosure aims to provide a friction stir point welding tool that prevents oil leakage from the base of the tool even when the tool's axis is tilted from the vertical. [Means for solving the problem]

[0008] A friction stir point joining tool according to one aspect of the present disclosure comprises a pin and a shoulder having a hollow portion into which the pin is inserted, wherein the shoulder has a cylindrical shoulder tip and a cylindrical shoulder root connected to the root end of the shoulder tip, and the hollow portion is formed by the shoulder tip and the shoulder root, and the pin has a cylindrical pin tip inserted into the shoulder tip and a cylindrical pin root connected to the root end of the pin tip and inserted into the shoulder root, a gap is formed between the outer circumferential surface of the pin and the inner circumferential surface of the shoulder, and at least one of the outer circumferential surface of the pin root and the inner circumferential surface of the shoulder root is formed of a sintered cemented carbide.

[0009] A friction stir point joining tool according to another aspect of the present disclosure comprises a pin and a shoulder having a hollow portion into which the pin is inserted, wherein the shoulder has a cylindrical shoulder tip and a cylindrical shoulder root continuous with the root end of the shoulder tip, and the hollow portion is formed by the shoulder tip and the shoulder root, and the pin has a cylindrical pin tip inserted into the shoulder tip and a cylindrical pin root connected to the root end of the pin tip and inserted into the shoulder root, a gap is formed between the outer circumferential surface of the pin and the inner circumferential surface of the shoulder, and the root side surface roughness, which is the value obtained by expressing the surface roughness of at least one of the outer circumferential surface of the pin root and the inner circumferential surface of the shoulder root, is such that the wetting spread rate of the oil over 3 to 20 seconds is 5.65 mm 2 This is a value that is less than / second.

[0010] A method of using a friction stir point welding tool according to yet another aspect of the present disclosure is a method of using a friction stir point welding tool described above, wherein an oil is filled into the gap between the outer surface of the pin and the inner surface of the shoulder, the tip of the tool is directed toward the object to be joined, and friction stir point welding is performed on the object to be joined, while tilting the axis of the tool from the vertical direction. [Effects of the Invention]

[0011] According to this disclosure, it is possible to provide a friction stir point welding tool that prevents oil leakage from the base of the tool even when the axis of the tool is tilted from the vertical. [Brief explanation of the drawing]

[0012] [Figure 1] This is a notched cross-sectional view showing the configuration of a friction stir point welding tool according to an embodiment of the present disclosure. [Figure 2] Figure 1 is an exploded view of a friction stir point welding tool. [Figure 3] Figure 1 is a schematic diagram of a friction stir point welding apparatus equipped with a friction stir point welding tool, the tool of which is filled with an oil. [Figure 4]This is an explanatory diagram showing examples of how the surface roughness of the inner circumferential surface of the shoulder base can be changed by altering the finishing process of the inner circumferential surface in Figure 1. The diagram schematically shows the roughness of the inner circumferential surface in the cases of (I) as-sintered, (II) micro-machining, (III) medium-machining, and (IV) rough machining. [Figure 5] Figure 1 is a diagram showing the entire pin of the tool inserted into the shoulder, and is a cross-sectional explanatory diagram showing the case where the clearance distance, which is the axial length of the gap at the base, is 42 mm. [Figure 6] Figure 1 is a cross-sectional diagram illustrating the case where the pin is pulled X mm towards the base, causing a portion of the pin base to protrude outside the shoulder, and the axial length of the gap at the base becomes 42 - X mm. [Figure 7] Figure 1 is a diagram showing the entire pin of the tool inserted into the hollow part of the shoulder, and is a cross-sectional explanatory diagram showing the volume ratio of the tip gap, base gap, and intermediate gap to the total volume of the gap. [Figure 8] This figure shows the results of varying the clearance distance and the ratio of oil dripped into the tool gap under room temperature and 70°C temperature conditions, in order to determine whether or not there is oil leakage from the base of the tool when the inner circumferential surface of the shoulder base of the tool is inverted. [Figure 9] Figure 1 shows the inner circumferential surface of the shoulder base, inverted to determine whether or not there is leakage of the lubricant from the base of the tool. This figure shows the results when the clearance distance and the ratio of the amount of oil dripped into the tool gap are changed under room temperature and 70°C temperature conditions. [Figure 10] This graph shows the change in the contact angle of an oil droplet immediately after dropping the oil onto the sample surface and 3 seconds later, in order to verify the difference in wettability of the oil at different surface roughnesses, for (I) as-sintered, (II) micro-machined, (III) semi-machined, and (IV) rough-machined surfaces. [Figure 11] This is an explanatory diagram showing the contact angle and wetting spread area of ​​oil droplets on a sample surface, illustrating the state of oil droplets in (I) as-sintered, (II) micro-machined, or (III) medium-machined cases. [Figure 12]It is an explanatory diagram showing the contact angle and wetting spread area of an oil droplet on the sample surface, and is a diagram showing the state of the oil droplet in the case of (IV) rough machining. [Figure 13] It is a diagram showing the change in the wetting spread of an oil droplet on the sample surface, and is a diagram showing the state of each oil agent 3 seconds and 50 seconds after dropping. [Figure 14] (I) As sintered, (II) micro machining, (III) medium machining, (IV) rough machining. It is a graph showing the change in the wetting spread area from 3 seconds to 50 seconds after dropping an oil agent on the sample surface. [Figure 15] (I) As sintered, (II) micro machining, (III) medium machining, (IV) rough machining. It is a bar graph showing the wetting spread rate from 3 seconds to 50 seconds after dropping an oil agent on the sample surface.

Embodiments for Carrying out the Invention

[0013] [First Embodiment] Hereinafter, based on the drawings, embodiments of the present disclosure will be described in detail. The friction stir spot welding tool according to the present disclosure can be applied to the manufacture of various joined bodies formed by overlapping two or more structural materials such as metal or resin plates, frames, exterior materials, or columnar materials by spot welding. The joined body to be manufactured becomes a constituent member of a structure such as an aircraft, a railway vehicle, or an automobile, for example.

[0014] (Configuration of Tool 1) As shown in FIGS. 1 to 2, the friction stir spot welding tool 1 includes a pin 11 and a shoulder 12 having a hollow portion 12B through which the pin 11 is inserted. Note that the drawings of the tool 1 in FIGS. 1 to 7 below are schematic diagrams and do not limit the actual tool shape.

[0015] As shown in Figure 2, the pin 11 is a cylindrical body whose diameter gradually decreases towards the lower end 11T. The pin 11 has a cylindrical pin tip 111, a cylindrical pin root 112, and a tapered pin middle section 113. The pin root 112 is connected to the root end of the pin tip 111 via the tapered pin middle section 113.

[0016] The pin tip 111 is the smallest outer diameter portion that forms the tip of the pin 11, and its tip surface is the lower end 11T of the pin 11. The pin root 112 is located at the axial root of the pin 11 and is a cylindrical portion with a larger diameter than the pin tip 111. The pin middle portion 113 is a tapered portion that connects the upper end of the pin tip 111 and the lower end of the pin root 112. The pin middle portion 113 has a lower end with the same outer diameter as the upper end of the pin tip 111 and an upper end with the same outer diameter as the lower end of the pin root 112. The pin middle portion 113 has a tapered outer shape in which the outer diameter widens from the lower end to the upper end. Note that if the regions corresponding to the pin tip 111 and the pin root 112 have the same or similar outer diameters, the tapered pin middle portion 113 may be omitted.

[0017] As shown in Figure 2, the shoulder 12 is made up of a cylindrical body whose inner diameter gradually decreases towards the lower end 12T. The shoulder 12 has a shoulder tip 121 with the smallest inner diameter, a shoulder root 122 with the largest inner diameter, and a shoulder intermediate 123 having a tapered inner surface 123a. The shoulder root 122 is connected to the root end of the shoulder tip 121 via the shoulder intermediate 123.

[0018] The shoulder tip portion 121 is the smallest inner diameter portion that forms the tip of the shoulder 12, and its tip surface is the lower end portion 12T of the shoulder 12. The lower end portion 12T is a ring-shaped portion. The shoulder root portion 122 is located at the axial root portion of the shoulder 12 and is a cylindrical portion having an inner diameter larger than the inner diameter of the shoulder tip portion 121. The shoulder middle portion 123 has a tapered inner surface 123a that connects the upper end of the shoulder tip portion 121 and the lower end of the shoulder root portion 122. The tapered inner surface 123a has a lower end with the same inner diameter as the shoulder tip portion 121, an upper end with the same inner diameter as the shoulder root portion 122, and a middle portion in which the inner diameter widens from the lower end to the upper end.

[0019] The shoulder 12 is formed by the shoulder tip 121, shoulder middle 123, and shoulder base 122, which together constitute the shoulder 12, creating a hollow section 12B. The hollow section 12B is open to the outside of the shoulder 12 through a tip opening 12A formed at the lower end of the shoulder tip 121 and a base opening 12C formed at the upper end of the shoulder base 122. In the actual tool 1 used, a gripping section connected to the shoulder drive unit 23 shown in Figure 3 is provided at the upper end of the shoulder base 122, but the gripping section is omitted in Figures 1 to 3.

[0020] The pin 11 is inserted into the hollow portion 12B with its tip 111 inserted into the shoulder tip 121 and its base 112 inserted into the shoulder base 122. This creates a gap C between the outer surface of the pin 11 and the inner surface of the shoulder 12 into which the oil A shown in Figure 3 can be filled.

[0021] The gap C has a tip gap portion C1 on the tip side of the tool 1, a root gap portion C2 on the root side of the tool 1, and an intermediate gap portion C3. The tip gap portion C1 is a cylindrical space sandwiched between the outer peripheral surface 111a of the pin tip portion 111 and the inner peripheral surface 121a of the shoulder tip portion 121. The root gap portion C2 is a cylindrical space sandwiched between the outer peripheral surface 112a of the pin root portion 112 and the inner peripheral surface 122a of the shoulder root portion 122. The intermediate gap portion C3 is a cylindrical space surrounded by the outer peripheral surface 111a of the pin tip portion 111 and the outer peripheral surface 113a of the pin intermediate portion 113, and the inner peripheral surface 122a of the shoulder root portion 122 and the tapered inner surface 123a of the shoulder intermediate portion 123.

[0022] The width of the above-mentioned gap C is a width that can be filled with the oil agent A, and is set to a width that allows the pin 11 to move relative to the shoulder 12 inside the hollow portion 12B, specifically, a linear reciprocating movement and a rotational movement in the axial direction. The widths w1, w2, and w3 of the tip gap portion C1, the root gap portion C2, and the intermediate gap portion C3 that constitute the gap C are set in consideration of the following points.

[0023] The width w1 of the tip gap portion C1 is set very narrow to prevent a part separated from the bonding material from adhering inside the tip gap portion C1 of the tool 1 during friction stir point joining. From such a viewpoint, the width w1 is set in a narrow range of about 0.01 to 0.1 mm. The width w2 of the root gap portion C2 is set wider than the width w1 of the tip gap portion C1 because the risk of adhesion of separated matter from the bonding material inside the root gap portion C2 is low. From such a viewpoint, the width w2 is set in a wide range of about 0.1 to 3.5 mm. The width w3 of the intermediate gap portion C3 is set to a width sufficiently wider than the width w2 of the root gap portion C2 in order to hold a sufficient amount of the oil agent A inside the tool 1 during friction stir point joining. Therefore, the widths w1, w2, and w3 of the root gap portion C2 and the intermediate gap portion C3 are set in the relationship of w1 < w2 < w3.

[0024] As the oil A to be filled into the gap C, when metal materials are friction stir point-joined as joining materials, a liquid or grease-like oil can be used that has the effect of preventing the adhesion of metal powder, which is separated from the metal materials during the joining process. For example, mineral oil or synthetic oil mainly composed of lubricating oil base oil or petroleum hydrocarbons can be used as the oil. Alternatively, mineral oil or synthetic oil to which molybdenum, graphite, solid paraffin, or metal powder has been added as a solid lubricant may also be used as the oil.

[0025] The viscosity of oil A, which fills gap C, is 1 to 101 mm² under a temperature of 40°C. 2 Range of / second, preferably 1-21mm 2 A viscosity in the range of / second is preferred.

[0026] (Configuration of friction stir point bonding device M) Figure 3 is a schematic diagram of a friction stir point welding apparatus M equipped with a friction stir point welding tool 1 configured as described above, and the tool 1 filled with lubricant A. The friction stir point welding apparatus M includes the friction stir point welding tool 1 configured as described above, a tool drive unit 2 that rotates and moves the tool 1 up and down, and a controller CT that controls the operation of each part of the friction stir point welding apparatus M, i.e., a control unit for the tool 1. Note that Figure 3 is marked with "up" and "down" directions, but this is for the convenience of explanation and is not intended to limit the actual direction of use of the tool 1.

[0027] Tool 1 is supported by various tool fixing parts. The tool fixing parts are, for example, the tip of an articulated robot. A backup 15 is positioned opposite the lower end surface of tool 1. At least two members to be joined are positioned between tool 1 and backup 15. Figure 3 shows an example in which an overlapping portion 30, in which a part of a first member 31 made of a flat plate and a part of a second member 32 also made of a flat plate overlap in the vertical direction, is positioned between tool 1 and backup 15.

[0028] In Figure 3, tool 1 is positioned so that its axis extends in the vertical direction. Pin 11 is rotatable around its axis R and can move up and down along the axis R. When tool 1 is used, the axis R and the point contact position W at the overlapping portion 30 are aligned.

[0029] The axis of the shoulder 12 is coaxial with the axis of the pin 11, i.e., the rotation axis R. The shoulder 12 is rotatable around the rotation axis R and can move up and down along the rotation axis R. The gap C between the outer surface of the pin 11 and the inner surface of the shoulder 12, specifically the tip gap portion C1, the base gap portion C2, and the intermediate gap portion C3 that constitute the gap C, is filled with lubricant A. Lubricant A enhances the lubrication between the pin 11 and the shoulder 12 and suppresses the adhesion of deposits in the gap C.

[0030] When filling the gap C with lubricant A, the pin 11 shown in Figure 1 should be raised until the middle portion 113 of the pin extends outside the shoulder base portion 122, and then lubricant A should be filled into the gap C using the lubrication device.

[0031] Tool 1 allows the pin 11 and shoulder 12 to move independently in the axial direction when friction stir point bonding is performed. That is, the shoulder 12 and the pin 11 inserted into the shoulder 12 can both rotate around the axis of rotation R and move relative to each other in the direction of the rotation axis R. Specifically, the pin 11 and shoulder 12 can not only move up and down simultaneously along the rotation axis R, but can also move independently, with one moving down and the other moving up.

[0032] Tool 1 in Figure 3 further includes a clamp 13 that covers the outer circumference of the shoulder 12. The clamp 13 is a cylindrical member with a hollow section into which the shoulder 12 is inserted. The axis of the clamp 13 is also coaxial with the rotation axis R. The clamp 13 does not rotate around its axis, but moves up and down, i.e., forward and backward, along the rotation axis R. The clamp 13 serves to surround the outer circumference of the pin 11 or the shoulder 12 when they perform friction stirring. The enclosure of the clamp 13 prevents the friction-stirred material from scattering and allows the friction-stirred point joint to be finished smoothly.

[0033] The backup 15 has a flat surface that contacts the lower surface of the overlapping portion 30 to be joined. The backup 15 is a backing member that supports the overlapping portion 30 when the pin 11 or shoulder 12 is pressed into the overlapping portion 30. The clamp 13 receives a biasing force from a pressurizing mechanism such as a spring and presses the overlapping portion 30 against the backup 15.

[0034] The tool drive unit 2 includes a rotary drive unit 21, a pin drive unit 22, a shoulder drive unit 23, a clamp drive unit 24, and a swivel drive unit 25. The rotary drive unit 21 includes a motor and drive gears, etc., and rotates the pin 11 and the shoulder 12 around the rotation axis R. The pin drive unit 22 is a mechanism that moves the pin 11 forward and backward along the rotation axis R. The pin drive unit 22 drives the pin 11 to press it into the overlapping portion 30 and to retract it from the overlapping portion 30. The shoulder drive unit 23 is a mechanism that moves the shoulder 12 forward and backward along the rotation axis R, causing the shoulder 12 to press into the overlapping portion 30 and to retract. The clamp drive unit 24 is a mechanism that moves the clamp 13 forward and backward along the rotation axis R. The clamp drive unit 24 moves the clamp 13 vertically toward the overlapping portion 30, pressing the overlapping portion 30 against the backup 15.

[0035] The swivel drive unit 25 is a mechanism that swivels the tool 1 in a direction that is inclined vertically. Depending on the shape of the product being manufactured, such as an aircraft, the point joint position W at the overlapping portion 30 of the first member 31 and the second member 32 to be joined may be oriented in a direction that is inclined vertically. For example, the point joint position W may be oriented in a horizontal direction or in a direction that is inclined upward from the horizontal direction. Even in such cases, the swivel drive unit 25 makes it possible to point the tip of the tool 1 toward the overlapping portion 30 by swiveling the tool 1 in a direction that is inclined vertically.

[0036] The controller CT consists of a microcomputer and other components, and controls the operation of the tool drive unit 2 and other mechanisms by executing a predetermined control program. Specifically, the controller CT controls the rotation drive unit 21 to cause the pin 11 and shoulder 12 to perform the required rotational movement. The controller CT also controls the pin drive unit 22, shoulder drive unit 23, clamp drive unit 24, and swivel drive unit 25 to cause the pin 11, shoulder 12, and clamp 13 to perform the required forward and backward movement and swivel movement.

[0037] (Friction bonding using friction stir point bonding device M) The friction bonding method using the friction stir point bonding apparatus M broadly includes a pin-first process in which the pin 11 of tool 1 is pressed into the overlapping portion of the bonding members first, and a shoulder-first process in which the shoulder 12 is pressed into the overlapping portion of the bonding members first.

[0038] For example, in the shoulder-first process, first, as a preheating step for the overlapping portion 30, the controller CT rotates the pin 11 and shoulder 12 around its axis at a predetermined number of rotations while the lower end of the tool 1 is in contact with the surface of the first member 31. Next, in the press-fitting step of the shoulder 12, the controller CT lowers the shoulder 12 and presses it into the overlapping portion 30, while retracting the pin 11 upward. This action stirs the material in the press-fitting area of ​​the shoulder 12. In addition, any overflow material that spills out from the overlapping portion 30 due to the press-fitting is released into the space inside the tip of the shoulder 12 created by the retraction of the pin 11. Thus, in this embodiment, the pin 11 is moved upward relative to the shoulder 12 during friction stir welding. Subsequently, in the backfilling step of the overflow material, the controller CT raises the shoulder 12 and retracts it, while lowering the pin 11. As the pin 11 descends, the overflow material that has been released into the space inside the tip of the shoulder 12 is filled back into the press-fit area of ​​the shoulder 12. Subsequently, in the leveling process, the pin 11 and the lower end surfaces of the shoulder 12 are returned to the height of the surface of the first member 31, and both are rotated to smooth the point joint portion. This makes it possible to join the first member 31 and the second member 32 at the point joint portion.

[0039] (Regarding preventing leakage of oil A from the base of tool 1) When applying tool 1 to the friction stir point welding apparatus M described above to perform friction welding, if the point welding position W of the overlapping portion 30 is oriented in a direction that is inclined vertically, the swivel drive unit 25 rotates tool 1 in the direction that is inclined vertically, so that the tip of tool 1 is used facing the overlapping portion 30.

[0040] In this embodiment, the tool 1 prevents leakage of the lubricant A from the base of the tool 1 even when the axis of the tool 1, i.e., the rotation axis R shown in the figure, is tilted from the vertical direction. To achieve this, the surface roughness of at least one of the outer circumferential surface 112a of the pin base portion 112 and the inner circumferential surface 122a of the shoulder base portion 122 is set to a range that prevents leakage of the lubricant A. Specifically, the base side surface roughness, which is the value obtained by expressing the surface roughness of at least one of the outer circumferential surface 112a of the pin base portion 112 and the inner circumferential surface 122a of the shoulder base portion 122 as an arithmetic mean roughness Ra, is set to a range greater than 0.04 and less than 5.9. In this embodiment, the base side surface roughness is set to the above range by adjusting the surface roughness of the inner circumferential surface 122a of the shoulder base portion 122 shown in Figure 4. By setting the root side surface roughness within the above range, when using tool 1 for joining work with the gap C between pin 11 and shoulder 12 filled with lubricant A, it is possible to prevent leakage of lubricant A from the root of tool 1 even when the axis of tool 1, i.e., the rotation axis R in Figure 3, is tilted from the vertical direction. It is also possible to prevent leakage of lubricant A from the root of tool 1 by setting the outer peripheral surface 112a of the pin root portion 112 to the above root side surface roughness.

[0041] For example, if tool 1 is rotated with its tip pointed diagonally upward or nearly directly upward, the base of tool 1 will be below the tip. Even in this case, by setting the base side surface roughness within the above range, the oil A is retained inside the base gap portion C2 of gap C, thus preventing leakage of oil A from the base of tool 1.

[0042] In the tool 1 of this embodiment, it is preferable that the pin 11 can move relative to the shoulder 12 in the axial direction by the controller CT controlling the pin drive unit 22 so that the axial length of the root gap portion C2 formed by the outer circumferential surface 112a of the pin root portion 112 and the inner circumferential surface 122a of the shoulder root portion 122 in the gap C is within a range of 27 mm or more. With the above configuration, it is possible to reliably prevent leakage of the lubricant A from the root of the tool 1.

[0043] In tool 1 of this embodiment, it is preferable that the inner circumferential surface 122a of the shoulder base portion 122 is formed of a sintered cemented carbide base material such that the root side surface roughness is in the range of greater than 0.04 and less than 5.9. By forming the inner circumferential surface 122a of the shoulder base portion 122 with a sintered cemented carbide base material, the inner circumferential surface 122a will have a predetermined dimension and a predetermined root side surface roughness. Therefore, leakage can be prevented without performing finishing work to achieve the predetermined root side surface roughness.

[0044] In the method of using tool 1 of this embodiment, first, as shown in Figure 3, the gap C between the outer surface of the pin 11 and the inner surface of the shoulder 12 is filled with oil A. Next, if the overlapping portion 30, which is the object to be joined by friction stir point welding, overlaps in a direction inclined from the vertical, the pivot drive unit 25 is used to pivot the axis of tool 1, causing it to tilt from the vertical, and the tip of tool 1 is directed toward the overlapping portion 30, which is the object to be joined by friction stir point welding. Then, friction stir point welding of the overlapping portion 30 is performed. In this way, even when friction stir point welding is performed with the tip of tool 1 directed toward a direction inclined from the vertical, since tool 1 of this embodiment has the above-mentioned base side surface roughness, it is possible to prevent leakage of oil A from the base of tool 1.

[0045] In the method of using tool 1 of this embodiment, it is preferable to fill the gap C with oil A in an amount that is 70% or less of the total volume of the gap C in tool 1. By filling the gap C with oil A within the above volume range, it is possible to reliably prevent leakage of oil A from the base of tool 1.

[0046] (Explanation of the demonstration experiment for preventing leakage of oil agent A) Next, using Figures 4-9, we will explain the demonstration experiment demonstrating the prevention of leakage of oil agent A, including tool 1 and its usage, which enabled the prevention of leakage of oil agent A as described above.

[0047] Figure 4 is an explanatory diagram showing examples of how the surface roughness of the inner circumferential surface of the shoulder base portion 122 in Figure 1 can be changed by altering the finishing process of the inner circumferential surface 122a, and is a diagram showing the roughness of each inner circumferential surface in the cases of (I) as-sintered, (II) micro-machining, (III) medium-machining, and (IV) rough machining.

[0048] Figure 4(I) shows that the inner circumferential surface 122a of the shoulder base 122 in the as-sintered state is formed from the sintered cemented carbide, resulting in a surface with low surface roughness. As a result, the surface roughness of the inner circumferential surface 122a is approximately 1.8 in terms of arithmetic mean roughness Ra. Furthermore, the inner diameter of the inner circumferential surface 122a is approximately the dimension specified in the design. In other words, it is possible to form the inner circumferential surface 122a in a near-net shape.

[0049] In Figure 4 (II) for micro-machining, (III) for medium-machining, and (IV) for rough machining, the inner circumferential surface 122a of the shoulder root portion 122 is a surface in which the surface roughness is increased in stages from (II) to (IV) by performing electrical discharge machining on the inner circumferential surface 122a formed from the sintered surface of the cemented carbide as shown in Figure 4 (I) above. In Figures 4 (II) to (IV), the surface roughness of the inner circumferential surface 122a is approximately 3.1 for micro-machining, approximately 4.8 for medium-machining, and approximately 5.9 for rough machining.

[0050] Of the (I) to (IV) in Figure 4, for (I) as-sintered, (II) micro-machined, and (III) medium-machined, the surface roughness of the inner circumferential surface 122a is approximately 1.8 in arithmetic mean roughness Ra for (I) as-sintered, approximately 3.1 for (II) micro-machined, and approximately 4.8 for (III) medium-machined. Since these fall within the range greater than 0.04 and less than 5.9 in arithmetic mean roughness Ra, it is considered that leakage from the base of tool 1 will not occur. On the other hand, for (IV) rough-machined, the roughness is approximately 5.9, which exceeds the above range, so it is considered that leakage of oil A from the base of tool 1 cannot be suppressed.

[0051] Therefore, using Figures 8-9, we verify that leakage of oil A from the base of tool 1 can be suppressed in the following states: (I) as sintered, (II) micro-machined, (III) semi-machined, and (IV) rough-machined, while it is difficult to suppress leakage of oil A from the base of tool 1 in the (IV) rough-machined state.

[0052] As shown in Figures 8-9, when oil A was dripped into the gap C of tool 1 at oil volume (%) of 35% and 70%, the clearance distance (mm) of tool 1 was changed from 27 to 42 mm, and tool 1 was inverted and held with the base of tool 1 facing downwards for 30 minutes to verify whether or not oil A leaked from the base of tool 1. This verification was performed at room temperature and at a room temperature of 70°C.

[0053] Figure 8 shows the results of testing whether or not oil A leaks from the base of tool 1, where the inner circumferential surface 122a of the shoulder base portion 122 in Figure 1 is in the as-sintered state as shown in Figure 4(I), by inverting tool 1. The test is conducted at room temperature and 70°C, and the ratio of the clearance distance, which is the axial length of the gap portion C2 at the base, to the amount of oil dripped into the gap C of tool 1 is changed accordingly.

[0054] Figure 9 shows the presence or absence of leakage of oil A when the clearance distance and the ratio of the amount of oil dripped into the tool gap are changed at room temperature and 70°C temperature conditions, in order to determine whether or not there is leakage of oil A from the base of the tool 1, which is in the rough machining state of the inner circumferential surface 122a of the shoulder base portion 122 in Figure 1 as shown in Figure 4(IV).

[0055] Here, region G1 in Figures 8-9 is the range where no leakage of oil A occurred at room temperature, and it also includes the range of region G2, while region G2 is the range where no leakage of oil A occurred at a temperature of 70°C. Region N1 in Figures 8-9 is the range where leakage of oil A occurred at room temperature, and region N2 is the range where oil A could not be filled into the gap C of tool 1.

[0056] The clearance distance shown in Figures 8-9 changes within the range of 27-42 mm depending on the amount the pin 11 is pulled out, as shown in Figures 5-6. Figure 5 is a diagram showing the state in which the entire pin 11 of tool 1 in Figure 1 is inserted into the hollow portion 12B of the shoulder 12, and is a cross-sectional explanatory diagram showing the case where the clearance distance, which is the axial length of the base gap portion C2, is 42 mm. Figure 6 is a cross-sectional explanatory diagram showing the case in which the pin 11 in Figure 1 is pulled out X mm towards the base side, i.e., to the left side of Figure 6, so that a part of the pin base portion 112 protrudes outside the shoulder 12, and the clearance distance, which is the axial length of the base gap portion C2, becomes 42-X mm. If the amount X mm that the pin 11 is pulled out in Figure 6 is changed within the range of 0-15 mm, the clearance distance changes within the range of 27-42 mm, as shown in Figures 8-9.

[0057] The amount of oil dropped (%) shown in Figures 8-9 will be explained in detail using Figure 7. Figure 7 is a diagram showing the entire pin 11 of tool 1 in Figure 1 inserted into the hollow portion 12B of shoulder 12, and is a cross-sectional explanatory diagram showing the volume ratio of the tip gap portion C1, the base gap portion C2, and the intermediate gap portion C3 to the total volume of gap C. As shown in Figure 7, the volume ratio of the tip gap portion C1 is 1.0%, the volume ratio of the base gap portion C2 is 62.4%, and the volume ratio of the intermediate gap portion C3 is 36.6%. In this case, the volume ratio of the tip of gap C, the sum of the volume ratio of the tip gap portion C1 and the volume ratio of the intermediate gap portion C3 is 37.6%. When 35% of the oil A is dropped relative to the total volume of gap C, that is, when the amount of oil dropped (%) is 35%, it will be approximately the same as the volume ratio of the intermediate gap portion C3, which is 36.6%. Furthermore, when 70% of the total volume of gap C is dispensed with oil A, that is, when the amount of dispensed oil (%) is 70%, it exceeds the sum of the volume ratio of the tip gap C1 and the volume ratio of the intermediate gap C3, which is 37.6%. This indicates that the amount of oil A fills not only the tip gap C1 and the intermediate gap C3 but also a portion of the base gap C2. The above 35% and 70% are the values ​​shown on the vertical axis of the graphs in Figures 8 and 9.

[0058] As can be seen in Figure 8, when the inner circumferential surface 122a of the shoulder base 122 is in the as-sintered state as shown in Figure 4(I), with a dripping oil amount of 35%, at room temperature, the clearance distance in the range of 27-42 mm falls within the range G1 where no oil leakage occurred, and at 70°C, the clearance distance in the range of 35-42 mm falls within the range G2 where no oil leakage occurred. Furthermore, with a dripping oil amount of 70%, at room temperature, the clearance distance in the range of 32-42 mm falls within the range G1 where no oil leakage occurred, and at 70°C, the clearance distance in the range of 37-42 mm falls within the range G2 where no oil A leakage occurred.

[0059] Furthermore, experiments have confirmed that no leakage of oil A occurred in the micro-machined state (Figure 4(II)) and the intermediate-machined state (Figure 4(III)) when the oil volume was 35%, the clearance distance was 27 mm, and the temperature was room. Experiments have also confirmed that no leakage of oil A occurred even when the oil volume was 35%, the clearance distance was 37 mm, and the temperature was 70°C. Therefore, it is presumed that the same judgment results as those obtained in Figure 8, which were verified in the as-sintered state (Figure 4(I)), can be obtained in the micro-machined state (Figure 4(II)) and the intermediate-machined state (Figure 4(III)).

[0060] Next, looking at Figure 9, we can see that in the rough machining state shown in Figure 4(IV), the inner circumferential surface 122a of the shoulder base 122 is within the range of region N1 where oil leakage occurs when the amount of dripping oil is 35% and the clearance distance is 27 mm at room temperature. Also, at 70°C, the clearance distance is 37 mm, so it falls outside the range of region G2 where oil leakage does not occur, and leakage occurs. With a dripping oil amount of 70%, at 70°C, the clearance distance is 39 mm, so it falls outside the range of region G2 where oil A leakage did not occur, and leakage occurs. Comparing the judgment results in Figure 8 and Figure 9, we can see that in the rough machining state shown in Figure 4(IV), both regions G1 and G2 where oil A leakage does not occur are narrow, as shown in Figure 9.

[0061] Based on the above results, it can be seen that in order to prevent leakage from the base of tool 1, the surface roughness of at least one of the outer circumferential surface 112a of the pin base portion 112 and the inner circumferential surface 122a of the shoulder base portion 122 should be set within a range that can prevent leakage of oil A. Specifically, it can be seen that the surface roughness should be set within a range greater than 0.04 and less than 5.9 in terms of the easy, arithmetic mean roughness Ra mentioned above.

[0062] Furthermore, from the judgment results in Figure 8, it can be understood that, in addition to setting the roughness of the root side surface as described above, if the clearance distance, i.e., the axial length of the root gap portion C2, is 27 mm or more, and the tool 1 is axially movable relative to the shoulder 12, then leakage of the lubricant A from the root of the tool 1 can be reliably prevented.

[0063] Furthermore, it is understood that when using tool 1 at an operating temperature of 70°C or higher, if oil A is filled into the gap C within a range where the clearance distance, i.e., the axial length of the gap C2 at the base, is 37 mm or more, it is possible to reliably prevent leakage of oil A from the base of tool 1 even at high operating temperatures.

[0064] (Relationship between contact angle and surface roughness) Figure 10 is a graph showing the change in the contact angle of the oil droplet immediately after oil A was dropped onto the surface of sample S shown in Figures 11-12 and 3 seconds later, corresponding to Figures 4(I)-4: (I) as-sintered, (II) micro-machined, (III) semi-machined, and (IV) rough-machined, in order to verify the difference in wettability of the oil at different surface roughnesses.

[0065] Figures 11 and 12 are explanatory diagrams showing the contact angle and wetting spread area of ​​oil droplets on the surface of sample S. Figure 11 shows the state of oil droplets in the following cases: (I) as-sintered, (II) micro-machined, or (III) semi-machined. Figure 12 shows the state of oil droplets in the following case: (IV) rough-machined.

[0066] As can be seen from the graph in Figure 10, in the cases of (I) as-sintered, (II) micro-machined, and (III) semi-machined, the surface roughness is in the range of average surface roughness Ra greater than 0.04 and less than 5.9, and the difference in the contact angle of the oil droplet immediately after dropping oil A and 3 seconds later is smaller than in the case of (IV) rough machining, indicating that the leakage prevention effect has improved.

[0067] Furthermore, in the cases of (II) micro-machining and (III) intermediate machining, the contact angle of the oil droplet is larger both immediately after dropping and 3 seconds later compared to the case of (IV) rough machining, indicating a significant improvement in the leakage prevention effect.

[0068] In the case of (IV) rough machining, where oil A leaks from the base of tool 1, the contact angle is significantly lower than in the case of the most recent (III) intermediate machining. The reason for this is thought to be as follows: In the state of oil droplet A on the surface of sample S in the cases of (I) as-sintered, (II) micro-machining, or (III) intermediate machining shown in Figure 11, the contact angle α is large, so the increase from the droplet area S1' immediately after dropping to the wetting spread area S1 after 3 seconds is small. A large contact angle α is thought to contribute to preventing leakage of oil A. On the other hand, in the case of (IV) rough machining shown in Figure 12, the surface of sample S has large irregularities, and the contact angle β is smaller than the contact angle α in Figure 11. Therefore, oil A is more likely to wet and spread through between two adjacent protrusions, and the increase from the droplet area S2' immediately after dropping to the wetting spread area S2 after 3 seconds is large. Consequently, it is thought that leakage prevention cannot be achieved.

[0069] (Regarding the rate of wetting) In addition to the setting of the roughness of the base side surface described above, at least one of the outer circumferential surface 112a of the pin base portion 112 and the inner circumferential surface 122a of the shoulder base portion 122 shall have a wetting spread speed of 5.65 mm for 3 to 20 seconds. 2 It is preferable to have a surface that reduces the temperature to less than 1 second. By adopting the above configuration, it is possible to reliably prevent leakage of oil A from the base of tool 1.

[0070] The above wetting spread rate will be further examined with reference to Figures 13-15. Figure 13 shows the change in the wetting spread of oil A on the surface of sample S in the case of rough machining (IV), which corresponds to Figure 4(IV). Looking at Figure 13, it can be seen that the wetting spread area of ​​oil A after 50 seconds of dropping expands rapidly compared to the wetting spread area of ​​oil A after 3 seconds of dropping.

[0071] Figure 14 is a graph showing the change in the area of ​​wetting spread on the surface of sample S from 3 seconds to 50 seconds after dropping oil A onto the surface, corresponding to Figures 4(I) to (IV): (I) as-sintered, (II) micro-machined, (III) medium-machined, and (IV) rough-machined. Looking at Figure 14, it can be seen that the rate of change in the area of ​​wetting spread is small in the cases of (I) as-sintered, (II) micro-machined, and (III) medium-machined, while the rate of change is larger in the case of (IV) rough-machined than in the cases of (I) to (III). In other words, the slope of the lines for (I) to (III) is gentle, while the slope of the line for (IV) is steeper than that of the lines for (I) to (III).

[0072] From the graph in Figure 14, the wetting spread rate for (I) as-sintered, (II) micro-machined, (III) medium-machined, and (IV) rough-machined can be represented as shown in Figure 15. Figure 15 is a bar graph showing the wetting spread rate on the surface of sample S from 3 seconds to 50 seconds after the oil agent is dropped onto the sample surface for (I) as-sintered, (II) micro-machined, (III) medium-machined, and (IV) rough-machined, corresponding to (I) to (IV) in Figure 4.

[0073] As can be seen in the graph in Figure 15, for (I) as-sintered, (II) micro-machined, and (III) medium-machined, the wetting spread rate from 3 seconds to 50 seconds after dropping oil A was 4 to 4.5 mm. 2 While the range is within the range of / second, (IV) in rough machining, the wetting spread rate is 5.65 mm 2 This is significantly larger than in the other cases (I) to (III). As can be seen in the results in Figure 15, the wetting spread rate of the oil agent from 3 to 20 seconds is 5.65 mm 2It can be seen that by having a surface that reduces the leakage rate to less than 1 second, leakage of oil A from the base of tool 1 can be reliably prevented.

[0074] (Regarding other parameters of surface roughness) In addition to the arithmetic mean roughness Ra mentioned above, other parameters that represent surface roughness include the maximum peak height Rp and the maximum valley height Rv. By optimizing the maximum peak height Rp and the maximum valley height Rv, it is possible to reliably prevent leakage of oil A from the base of tool 1.

[0075] Specifically, the surface roughness of at least one of the outer circumferential surface 112a of the pin base portion 112 and the inner circumferential surface 122a of the shoulder base portion 122 is preferably set to 6.9 or more and less than 29.2 at the maximum peak height Rp, in addition to the arithmetic mean roughness Ra setting described above. By adopting the above configuration, it is possible to reliably prevent leakage of the lubricant A from the base of the tool 1.

[0076] Furthermore, it is preferable that the surface roughness of at least one of the outer circumferential surface 112a of the pin base portion 112 and the inner circumferential surface 122a of the shoulder base portion 122 be set to 5.4 or more and less than 22.5 in terms of the maximum valley height Rv, in addition to the setting of the arithmetic mean roughness Ra described above. By adopting the above configuration, it is possible to reliably prevent leakage of the lubricant A from the base of the tool 1.

[0077] [Second Embodiment] In the first embodiment described above, in order to prevent leakage of the lubricant A from the base of the tool 1, the surface roughness of at least one of the outer circumferential surface 112a of the pin base portion 112 and the inner circumferential surface 122a of the shoulder base portion 122 is considered, i.e., only the surface roughness on the base side of the tool 1 is considered, and the surface roughness is set to a range greater than 0.04 and less than 5.9 in terms of arithmetic mean roughness Ra.

[0078] In the second embodiment, attention was paid to both the surface roughness at the base and the surface roughness at the tip of the tool 1, and the ratio of the surface roughness at the base to the surface roughness at the tip of the tool 1 was optimized to prevent leakage of the oil A from the base of the tool 1.

[0079] In other words, when the surface roughness of at least one of the outer circumferential surface 112a of the pin base 112 and the inner circumferential surface 122a of the shoulder base 122 is expressed in terms of arithmetic mean roughness Ra, and the surface roughness of at least one of the outer circumferential surface 111a of the pin tip 111 and the inner circumferential surface 121a of the shoulder tip 121 is expressed in terms of arithmetic mean roughness Ra, the surface roughness ratio, which is the value obtained by dividing the root side roughness by the tip side roughness, is set to a range greater than 1 and less than or equal to 118. By setting the root side roughness and tip side roughness within the above range, when the tool 1 is used for joining work with the gap C between the pin 11 and the shoulder 12 filled with lubricant A, the lubricant A does not leak from the base of the tool 1 even when the axis of the tool 1 is tilted from the vertical.

[0080] Here, the root side surface roughness is set to a range greater than 0.04 and less than 5.9 in terms of arithmetic mean roughness Ra, for example, in the same way as in the first embodiment described above, in order to prevent oil A from leaking from the root of the tool 1. The tip side surface roughness is set to be less than the root side surface roughness in order to suppress the adhesion of separated material from the bonding material inside the tip gap portion C1. Specifically, the tip side surface roughness is set to a range of 0.04 or more and 1.8 or less in terms of arithmetic mean roughness Ra. Therefore, the surface roughness ratio, which is the value obtained by dividing the root side surface roughness by the tip side surface roughness in terms of arithmetic mean roughness Ra, is set to a range greater than 1 and 118 or less, as described above, thereby preventing oil A from leaking from the root of the tool 1.

[0081] The width w2 of the base gap portion C2 is set to a wide range of about 0.1 to 3.5 mm, for example, as in the first embodiment described above. The width w1 of the tip gap portion C1 is set to a narrow range of about 0.01 to 0.1 mm, as in the first embodiment described above, in order to suppress adhesion of separated material from the bonding material. Therefore, the ratio of the width w2 of the base gap portion C2 to the width w1 of the tip gap portion C1, i.e., w2 / w1, is set to a range of 1 to 350, preferably 3 to 150, and more preferably 5 to 50.

[0082] Furthermore, the other configurations and usage methods of Tool 1 in the second embodiment are the same as those of Tool 1 and usage methods in the first embodiment described above, so a description will be omitted.

[0083] [Summary of this disclosure] A friction stir point joining tool according to a first aspect of the present disclosure comprises a pin and a shoulder having a hollow portion into which the pin is inserted, wherein the shoulder has a cylindrical shoulder tip and a cylindrical shoulder root connected to the root end of the shoulder tip, and the hollow portion is formed by the shoulder tip and the shoulder root, and the pin has a cylindrical pin tip inserted into the shoulder tip and a cylindrical pin root connected to the root end of the pin tip and inserted into the shoulder root, a gap is formed between the outer circumferential surface of the pin and the inner circumferential surface of the shoulder, and the root side surface roughness, which is the value obtained by expressing the surface roughness of at least one of the outer circumferential surface of the pin root and the inner circumferential surface of the shoulder root as an arithmetic mean roughness Ra, is set in a range greater than 0.04 and less than 5.9.

[0084] According to the first embodiment, by setting the root side surface roughness within the above range, when the tool is used for joining work with the gap between the pin and the shoulder filled with lubricant, it is possible to prevent leakage of lubricant from the root of the tool even when the axis of the tool is tilted from the vertical.

[0085] A friction stir point joining tool according to a second aspect of the present disclosure comprises a pin and a shoulder having a hollow portion into which the pin is inserted, wherein the shoulder has a cylindrical shoulder tip and a cylindrical shoulder base continuous with the base end of the shoulder tip, and the hollow portion is formed by the shoulder tip and the shoulder base, and the pin has a cylindrical pin tip inserted into the shoulder tip and a cylindrical pin root connected to the base end of the pin tip and inserted into the shoulder base The pin has a base portion, a gap is formed between the outer surface of the pin and the inner surface of the shoulder, and the surface roughness of at least one of the outer surface of the pin base portion and the inner surface of the shoulder base portion is expressed in terms of arithmetic mean roughness Ra as the base side surface roughness, and the surface roughness of at least one of the outer surface of the pin tip portion and the inner surface of the shoulder tip portion is expressed in terms of arithmetic mean roughness Ra as the tip side surface roughness, the surface roughness ratio, which is the value obtained by dividing the base side surface roughness by the tip side surface roughness, is set in a range greater than 1 and less than or equal to 118.

[0086] According to the second embodiment, by setting the root side roughness and tip side roughness within the above range, when the tool is used for joining work with the gap between the pin and the shoulder filled with lubricant, the lubricant will not leak from the root of the tool even when the axis of the tool is tilted from the vertical.

[0087] A friction stir point bonding tool according to a third aspect of this disclosure is a friction stir point bonding tool according to the first and second aspects, wherein the root side surface roughness is such that the wetting spread rate of the oil over 3 to 20 seconds is 5.65 mm 2 This is a value that is less than / second.

[0088] According to the third embodiment, it is possible to reliably prevent oil leakage from the base of the tool.

[0089] A friction stir point joining tool according to a fourth aspect of this disclosure is a friction stir point joining tool according to the first to third aspects, wherein the root side surface roughness is a value such that the maximum peak height Rp is 6.9 or more and less than 29.2.

[0090] According to the fourth embodiment, it is possible to reliably prevent oil leakage from the base of the tool.

[0091] A friction stir point joining tool according to a fifth aspect of this disclosure is a friction stir point joining tool according to the first to fourth aspects, wherein the root side surface roughness is a value such that the maximum valley height Rv is 5.4 or more and less than 22.5.

[0092] According to the fifth embodiment, it is possible to reliably prevent oil leakage from the base of the tool.

[0093] A friction stir point joining tool according to a sixth aspect of the present disclosure is a friction stir point joining tool according to a first to fifth aspect, wherein the pin is axially movable relative to the shoulder within a range in which the axial length of the root gap portion formed by the outer circumferential surface of the pin root portion and the inner circumferential surface of the shoulder root portion in the gap is 27 mm or more.

[0094] According to the sixth embodiment, it is possible to reliably prevent oil leakage from the base of the tool.

[0095] A friction stir point joining tool according to the seventh aspect of this disclosure is a friction stir point joining tool according to the first to sixth aspects, wherein at least one of the outer circumferential surface of the pin root portion and the inner circumferential surface of the shoulder root portion is formed of a sintered cemented carbide base such that the root side surface roughness is in the range greater than 0.04 and less than 5.9.

[0096] According to the seventh embodiment, at least one of the outer circumferential surface of the pin base and the inner circumferential surface of the shoulder base is formed with a sintered cemented carbide base so that the base side surface roughness is in the range of greater than 0.04 and less than 5.9, thereby the inner circumferential surface has a predetermined dimension and a predetermined base side surface roughness. Therefore, leakage can be prevented without performing finishing work to achieve a predetermined base side surface roughness.

[0097] A method for using a friction stir point bonding tool according to the eighth aspect of this disclosure is a method for using a friction stir point bonding tool according to the first to seventh aspects, wherein an oil is filled into the gap between the outer surface of the pin and the inner surface of the shoulder, the tip of the tool is directed toward the object to be bonded while tilting the axis of the tool from the vertical, and friction stir point bonding is performed on the object to be bonded.

[0098] According to the eighth aspect, when performing friction stir point welding using the tools according to the first to seventh aspects, an oil is filled into the gap between the outer surface of the pin and the inner surface of the shoulder, and the tip of the tool is directed toward the object to be joined while tilting the tool from the vertical direction, thereby performing friction stir point welding of the object to be joined. In this way, even when friction stir point welding is performed with the tip of the tool tilted from the vertical direction, since the tool of this disclosure has the above-mentioned roughness of the base side surface, it is possible to prevent leakage of the oil from the base of the tool.

[0099] A method for using a friction stir point bonding tool according to a ninth aspect of this disclosure is the method for using a friction stir point bonding tool according to an eighth aspect, wherein the oil is filled into the gap in an amount equal to or less than 70% of the total volume of the gap in the tool.

[0100] According to the ninth aspect, by filling the gap with oil within the above volume range, it is possible to reliably prevent oil leakage from the base of the tool. [Explanation of Symbols]

[0101] 1 Tool 11 pins 12 shoulders 12B Hollow part 111 Pin tip 112 Pin base 112a Outer surface 121 Shoulder tip 122 Shoulder base 122a Inner surface A oil-based agent C Gap C1 Tip gap C2 Gap at the base

Claims

1. Ping, A shoulder having a hollow portion through which the aforementioned pin is inserted, Equipped with, The shoulder has a cylindrical shoulder tip and a cylindrical shoulder base connected to the base end of the shoulder tip, and the hollow portion is formed by the shoulder tip and the shoulder base. The pin has a cylindrical pin tip that is inserted into the shoulder tip, and a cylindrical pin base that is connected to the base end of the pin tip and inserted into the shoulder base. A gap is formed between the outer surface of the pin and the inner surface of the shoulder. At least one of the outer circumferential surface of the pin base and the inner circumferential surface of the shoulder base is formed of a sintered cemented carbide. A tool for friction stir point bonding.

2. Ping, A shoulder having a hollow portion through which the aforementioned pin is inserted, Equipped with, The shoulder has a cylindrical shoulder tip and a cylindrical shoulder base connected to the base end of the shoulder tip, and the hollow portion is formed by the shoulder tip and the shoulder base. The pin has a cylindrical pin tip that is inserted into the shoulder tip, and a cylindrical pin base that is connected to the base end of the pin tip and inserted into the shoulder base. A gap is formed between the outer surface of the pin and the inner surface of the shoulder. The root side surface roughness, which is the value obtained by expressing the surface roughness of at least one of the outer circumferential surface of the pin root and the inner circumferential surface of the shoulder root as an arithmetic mean roughness Ra, is obtained when the wetting spread rate of the oil agent over 3 to 20 seconds is 5.65 mm. ２ The value is less than / second. A tool for friction stir point bonding.

3. In the friction stir point bonding tool according to claim 1 or 2, A friction stir point welding tool, wherein the surface roughness of at least one of the outer circumferential surface of the pin root and the inner circumferential surface of the shoulder root is set to a value expressed as an arithmetic mean roughness Ra, which is the root side surface roughness, and is set to be in a range greater than 1.8 and less than 5.

9.

4. In the friction stir point bonding tool according to claim 1, The aforementioned root side surface roughness is such that it is 6.9 or more and less than 29.2 at the maximum peak height Rp, in a friction stir point joining tool.

5. In the friction stir point bonding tool according to claim 1, The aforementioned root side surface roughness is such that it is 5.4 or more and less than 22.5 at the maximum valley height Rv, in a friction stir point joining tool.

6. In the friction stir point bonding tool according to claim 1, The pin is a friction stir point joining tool that is axially movable relative to the shoulder within a range in which the axial length of the root gap portion formed by the outer circumferential surface of the pin root portion and the inner circumferential surface of the shoulder root portion in the gap is 27 mm or more.

7. In the method of using the friction stir point bonding tool described in claim 1, The gap between the outer surface of the pin and the inner surface of the shoulder is filled with an oily agent. The tip of the tool is directed toward the object to be joined, with the axis of the tool tilted from the vertical, The friction stir spot bonding of the objects to be joined is performed. Instructions for using friction stir point welding tools.

8. In the method of using the friction stir point bonding tool described in claim 7, A method for using a friction stir point welding tool, comprising filling the gap with the aforementioned oil in an amount of 70% or less of the total volume of the gap in the tool.

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