JP2008055486A - Friction pressure-welded component and friction pressure-welding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a friction pressure-welded component for which variation in strength is small and the strength can correctly be grasped, and to provide a friction pressure-welding method. <P>SOLUTION: In the friction pressure-welded component obtained by subjecting the first member 10 and the second member 20 to friction pressure welding, each notch by burrs 11a, 11b formed on the side of the first member 10 is made smaller than each notch by burrs 21a, 21b formed on the side of the second member 20. Alternatively, in a friction pressure-welded component obtained by subjecting the cylindrical part 11 of the first member 10 and the cylindrical part 21 of the second member 20 to friction pressure welding, the notch by the burr 11a formed at the inner space side of the first member 10 is made smaller than the notch by the burr 21a formed at the inner space side of the second member 20. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a friction welding component and a friction welding method.

  Steel materials have been used for rod-like parts (hereinafter referred to as “suspension parts”) such as upper links, lower links, and radius rods. However, in recent years, aluminum alloy materials have been used from the viewpoint of weight reduction of vehicles. For example, Patent Document 1 discloses a suspension component in which an aluminum alloy end member is friction-welded to both ends of an aluminum alloy pipe-shaped member.

  Friction welding is a kind of solid-phase bonding, so it does not have the defects found in fusion welding, and it does not require special skills such as MIG welding or TIG welding, so that various members have a certain quality. Because it can be joined with a wide range, it is used in a wide range of fields.

Japanese Patent Laid-Open No. 11-156562

  When the pipe-shaped member and the end member are joined by friction welding, the part softened by the frictional heat is discharged as burrs. However, when this burr is left without being cut, the burr is notched (change in cross section). Part), stress concentrates on this part, and the strength (static strength, fatigue strength, etc.) at the part decreases, so it is necessary to design suspension parts in anticipation of the strength reduction due to burrs. There is.

  By the way, the strength of the part including the burr (that is, the degree of stress concentration) depends on the burr shape (the shape of the notch due to the burr). Variation will occur. If the variation in strength in the part including burrs can be reduced, the failure mode and durability of the suspension parts can be grasped more accurately, and the design of the suspension parts can be rationalized. However, even a slight difference in the material strength, dimensional tolerance, friction welding conditions, and the like of the pipe-shaped member and the end member causes variation in the burr shape, which is very difficult in practice.

  The above-mentioned problem is not limited to suspension parts formed by friction welding the pipe-shaped member and the end member, but also applies to friction welding parts formed by friction welding the first member and the second member. It is.

  From this point of view, the present invention provides a friction welding component and a friction welding method in which the variation in the strength of the friction welding portion is small and the strength can be accurately grasped even if the burr shape varies. The task is to do.

  A friction welding component according to the present invention for solving such a problem is a friction welding component formed by friction welding a first member and a second member, and is a notch formed by a burr formed on the first member side. Is smaller than the notch formed by the burr formed on the second member side.

  In short, the present invention forms a burr that is steeper than the burr formed on the second member side on the first member side, thereby reducing the shape factor (stress concentration coefficient) on the first member side relative to the bonding interface to the second. It is characterized in that it is larger than the shape factor on the member side. That is, the burr bottom radius and burr bottom angle of the burr formed on the first member side are made smaller than the burr bottom radius and burr bottom angle of the burr formed on the second member side, and the cross section on the first member side It is characterized in that the change is steeper than the cross-sectional change on the second member side. In this way, the stress concentration level in the burr portion on the first member side is always higher than the stress concentration level in the burr portion on the second member side. It is sufficient to design considering only the above. This makes it possible to rationalize the design of the friction welding parts.

  In the friction welding part formed by friction welding the cylindrical part of the first member and the cylindrical part of the second member, the notch formed by the burr formed on the inner peripheral side of the cylindrical part of the first member It is good to make it smaller than the notch by the burr | flash formed in the inner peripheral side of the cylindrical part of a member.

  In addition, in the friction welding component formed by friction welding the cylindrical portion of the first member and the cylindrical portion of the second member, the outer diameter of the cylindrical portion of the first member is set to the outer diameter of the cylindrical portion of the second member. Should be equal. In this way, the burr bottom radius and burr bottom angle of the burr formed on the inner side of the first member are always larger than the burr bottom radius and burr bottom angle of the burr formed on the inner side of the second member. Since it becomes small, it becomes easy to specify the destruction mode. In addition, since there is no step between the outer peripheral surface of the cylindrical portion of the first member and the outer peripheral surface of the cylindrical portion of the second member, it is possible to easily perform the work of removing the burrs formed on the outer peripheral side.

  When the first member and the second member are made of JIS standard aluminum alloy 6061-T6, it is desirable that the shape factor on the first member side with respect to the bonding interface is 2.0 or more. This reduces the variation of the notch coefficient (fatigue strength when there is no stress concentration / fatigue strength when there is stress concentration), so the fracture strength of the first member (that is, the fracture strength of the friction welded part) Can be grasped more accurately. In order to set the shape factor on the first member side to 2.0 or more, for example, the burr bottom angle of the burr formed on the first member side may be an acute angle.

  In the present invention, the area of the abutting surface of the first member before the friction welding is made smaller than the area of the abutting surface of the second member before the friction welding, or the first member before the friction welding The cross-sectional secondary moment of the abutting surface may be smaller than the cross-sectional secondary moment of the abutting surface of the second member before the friction welding. Even when the first member and the second member are made of dissimilar metals showing a difference in strength (especially high temperature strength difference) or made of the same kind of metal, an apparent strength difference (especially high temperature) In cases such as showing a difference in strength, the strength of the first member may be lower than the strength of the second member. If it does in this way, it becomes possible to make the notch by the burr | flash formed in the 1st member side smaller than the notch by the burr | flash formed in the 2nd member side simply and reliably. In other words, the burr bottom radius and burr bottom angle of the burr formed on the first member side can be easily and reliably made smaller than the burr bottom radius and burr bottom angle of the burr formed on the second member side. It becomes.

  In the friction welding component formed by friction welding the cylindrical portion of the first member and the cylindrical portion of the second member, the thickness of the cylindrical portion of the first member before the friction welding is set to the thickness of the first member before the friction welding. If the thickness is smaller than the wall thickness of the cylindrical part of the two members, the burr bottom radius and burr bottom angle of the burr formed on the first member side can be set easily and reliably on the burr bottom radius of the burr formed on the second member side. It becomes possible to make it smaller than the burr bottom angle.

  The friction welding method according to the present invention for solving the above-described problem is a method of friction welding the first member and the second member, and the first member and the second member are abutted while rotating relative to each other. When the first member is fluidized first, the notch formed by the burr formed on the abutting surface side of the first member is made smaller than the notch formed by the burr formed on the second member side. It is characterized by doing.

  According to such a friction welding method, it is possible to obtain a friction welding component in which variation in strength is small and the magnitude of strength can be accurately grasped. That is, in the friction welded part obtained by this friction welding method, the stress concentration in the burr part on the first member side is always higher than the stress concentration in the burr part on the second member side. For the stress concentration at, only the first member side needs to be considered.

  When the cylindrical portion of the first member and the cylindrical portion of the second member are friction-welded, when the cylindrical portion of the first member and the cylindrical portion of the second member are abutted while rotating relative to each other, By first fluidizing the first member, a notch by a burr formed on the inner peripheral side of the cylindrical portion of the first member is formed on the inner peripheral side of the cylindrical portion of the second member. What is necessary is just to make it smaller than the notch by a burr | flash.

  In order to fluidize the first member first, for example, the first member may be heated to a temperature higher than that of the second member. Further, the area of the abutting surface of the first member before the friction welding is made smaller than the area of the abutting surface of the second member before the friction welding, or the abutting of the first member before the friction welding. The first member can also be fluidized first by keeping the cross-sectional secondary moment of the surface smaller than the cross-sectional secondary moment of the abutting surface of the second member before the friction welding. Furthermore, even when the first member and the second member are made of different metals showing a difference in strength (especially, high temperature strength difference), or even when made of the same kind of metal, an apparent strength difference (especially high temperature) In cases such as showing a difference in strength, the first member can be fluidized first by forming the first member with a material having a lower strength than the second member.

  In addition, in the case of friction welding the cylindrical portion of the first member and the cylindrical portion of the second member, the thickness of the cylindrical portion of the first member before the friction welding is set to the cylinder of the second member before the friction welding. By making it smaller than the thickness of the part, the first member can be fluidized first.

  According to the friction welding component according to the present invention, the variation in strength is small, and the strength can be accurately grasped. In addition, according to the friction welding method according to the present invention, it is possible to obtain a friction welding component in which variation in strength is small and the strength can be accurately grasped.

  The best mode for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the following embodiment, the case where the friction welding component is a suspension rod which is a kind of suspension component is illustrated, but the application of the friction welding component according to the present invention is not limited.

  As shown in FIG. 1A, the friction welding component 1 according to this embodiment is formed by friction welding the second members 20 and 20 as end members to both ends of the first member 10 as a pipe-like member. Is. In addition, since the main structure of the two 2nd members 20 and 20 is the same, in the following description, only the 2nd member 20 of one side (right side in FIG. 1) is demonstrated, and the other 2nd member 20 is demonstrated. The detailed description of is omitted.

  As shown in FIG. 1 (b), the first member 10 is made of an extruded shape made of an aluminum alloy having a circular tube shape, and a cylinder formed on each of a main body portion 12 and both end portions of the main body portion 12. Part 11. The cylindrical portion 11 before friction welding has a cylindrical shape with no cross-sectional change in the extrusion direction. The main body 12 also has a cylindrical shape with no cross-sectional change in the extrusion direction, and has the same cross-sectional shape as the cylindrical portion 11.

  Each of the second members 20 is formed using an extruded shape made of an aluminum alloy, and includes a cylindrical portion 21 and a cross-section changing portion 22. The cylindrical portion 21 before friction welding has a cylindrical shape with no cross-sectional change. The cylindrical portion 21 is formed into a cylindrical shape by subjecting a part of the extruded shape to be the second member 20 to cutting or drilling.

  The type of the aluminum alloy is not particularly limited. However, when the friction welding part 1 is used as a suspension part, an Al—Mg—Si based alloy subjected to T6 treatment (a JIS standard 6000 series aluminum alloy and solutionized). It is desirable that a quenching treatment be performed after the treatment, followed by an artificial aging treatment). In particular, an Al—Mg—Si based alloy (JIS standard aluminum alloy 6061-T6) treated with T6 has high strength (0.2% proof stress of 245 MPa or more) and durability (stress corrosion cracking resistance and weather resistance). It is even more desirable. Moreover, the 1st member 10 and the 2nd member 20 do not need to be an extrusion shape material, and may be a casting (including die-casting). Incidentally, when a suspension part is formed using the first member 10 and the second member 20 made of a cast product, it is desirable to use an AC4C alloy or an ADC3 alloy.

In the present embodiment, the thickness t ₁ of the cylindrical portion 11 of the first member 10 before the friction welding is smaller than the thickness t ₂ of the cylindrical portion 21 of the second member 20 before the friction welding. Further, the outer diameter of the cylindrical portion 11 of the first member 10 is equal to the outer diameter of the cylindrical portion 21 of the second member 20. That is, in this embodiment, the area of the abutting surface (end surface of the cylindrical portion 11) 11c of the first member 10 before the friction welding is equal to the abutting surface (end surface of the cylindrical portion 21) 21c of the second member 20 before the friction welding. And the second moment of section of the abutting surface 11 c of the first member 10 is smaller than the second moment of section of the abutting surface 21 c of the second member 20. In other words, the tip end portion of the cylindrical portion 11 of the first member 10 is more easily deformed than the tip end portion of the cylindrical portion 21 of the second member 20 during friction welding.

  Here, a method for friction welding the first member 10 and the second member 20 (that is, a method for manufacturing the friction welding component 1) will be described. The friction welding method according to the present embodiment includes a preparation process, a friction process, and an upset process.

  In the preparation process, the first member 10 is gripped by a clamp of a friction welding apparatus (not shown), and the central axis of the cylindrical portion 21 of the second member 20 is coaxial with the central axis of the cylindrical portion 11 of the first member 10. It is gripped by the chuck of the spindle of the friction welding apparatus (not shown).

  In the friction process, while the first member 10 and the second member 20 are relatively rotated, the second member 20 is advanced toward the first member 10, and the abutting surface 11 c of the cylindrical portion 11 of the first member 10 and the second member 10 are moved forward. The abutting surface 21c of the cylindrical portion 21 of the member 20 is abutted and a friction pressure is applied to the abutting surfaces 11c and 21c. The relative rotational speed, the friction pressure, the friction deviation, the friction deviation speed, and the like may be appropriately set in consideration of the material of the first members 10 and 20 and the dimensions and shapes of the cylindrical portions 11 and 21.

  When pressure is applied to the abutting surfaces 11c and 21c while relatively rotating the cylindrical portions 11 and 21, softened portions that are softer than the base material are formed around the abutting surfaces 11c and 21c by frictional heat, and the fluidity of the softened portions is increased. Then, it is pushed out into and out of the cylindrical portions 11 and 21, and burrs begin to be formed. In the present embodiment, the area of the abutting surface 11c of the first member 10 is smaller than the area of the abutting surface 21c of the second member 20, and the first member 10 and the second member 20 are the same material. The stress generated in the cylindrical portion 11 of the member 10 is greater than the stress generated in the cylindrical portion 21 of the second member 20, and the first member 10 has a smaller cross-sectional area than the second member 20. Deformation resistance is small because heat diffusion due to conduction is small and the temperature is high. Therefore, the cylindrical portion 11 of the first member 10 is fluidized first. That is, the tip of the cylindrical portion 11 of the first member 10 starts to deform (plastic fluidization) before the second member due to the friction pressure, and as a result, the burrs located on the first member 10 side with respect to the bonding interface J. The notch (cross-sectional change) due to sag becomes steeper than the notch (cross-sectional change) due to the burr on the second member 20 side. In addition, the oxide film, the deposits, and the like existing on the abutting surfaces 11c and 21c of the cylindrical portions 11 and 21 before the friction welding are discharged together with the burrs.

  The upset process is a process of applying an upset pressure, and is performed after or just before the end of the friction process. That is, the pressure applied to the abutting surfaces 11c and 21c of the cylindrical portions 11 and 21 is increased more than the friction pressure, and when the predetermined upset pressure is reached, the upset pressure is maintained for a predetermined time and the cylindrical portions 11 and 21 are pressure bonded. . When an upset pressure is applied, the softened part formed in the friction process is pushed out into and out of the cylindrical parts 11 and 21 following the friction process, and as a result, as shown in FIG. As a result, a bonding interface J having no oxide film or the like is formed.

The form of the joint formed through such a process will be described in more detail with reference to FIG. As described above, since the cylindrical portion 11 of the first member 10 is more easily deformed than the cylindrical portion 21 of the second member 20, the notches formed by the burrs 11a and 11b formed on the first member 10 side are first. It becomes smaller than the notch by the burr | flash 21a, 21b formed in the two member 20 side. That is, the burr bottom angle θ _1a of the burr 11a formed on the inner peripheral side (inner side) of the cylindrical part 11 is smaller than the burr bottom angle θ _2a of the burr 21a formed on the inner peripheral side of the cylindrical part 21. Thus, the burr bottom radius R _1a of the burr 11a is smaller than the burr bottom radius R _2a of the burr 21a. Similarly, burrs 11b are formed on the outer peripheral side of the cylindrical portion 11 burrs bottom angle theta _1b is, the burr 21b formed on the outer peripheral side of the cylindrical portion 21 Ri of less than burr bottom angle theta _2b, the burrs 11b The burr bottom radius R _1b is smaller than the burr bottom radius R _2b of the burr 21b.

The burr bottom radii R _1a , R _1b , R _2a , and R _2b are cross-sectional shapes of rising portions of the burrs 11a, 11b, 21a, and 21b, and are arcs that pass through the thickness change points P1, P2, Q1, and Q2. This means the minimum radius when approximated, and the burr bottom angles θ _1a , θ _1b , θ _2a , θ _2b are at the contact points (or intersections) of the arcs and the contour lines of the burr 11a, 11b, 21a, 21b. Tangent lines S _1a , S _1b , S _2a , S _2b with respect to the arc and straight lines T _1a , T 2 that are parallel to the central axes of the cylindrical portions 11, 21 and pass through the thickness change points P 1, P 2, Q 1, Q 2. _It means the angle formed by _1b , T _2a and T _2b .

In the present embodiment, the burr bottom angles θ _1a and θ _{1b of} the burrs 11a and 11b formed on the first member 10 side are acute angles (less than π / 2 (rad)).

  In addition, since the softening part formed by frictional heat tends to be pushed out to the outer peripheral side rather than the inner peripheral side of the cylindrical parts 11 and 21, the burr 11a formed on the inner peripheral side of the cylindrical parts 11 and 21. , 21a is smaller than the volume of burrs 11b, 21b formed on the outer peripheral side. As a result, the thickness change point P1 on the inner peripheral side of the cylindrical portion 11 is greater than the thickness change point Q1 on the outer peripheral side. Is closer to the joining interface J, and the thickness change point P2 on the inner peripheral side of the cylindrical portion 21 is closer to the joining interface J than the thickness change point Q2 on the outer peripheral side.

  By the way, due to frictional heat during pressure welding, a heat affected zone (HAZ = Heat Affected Zone) having a strength and material different from the strength of the base material inevitably occurs around the joint interface J. It tends to increase as it approaches the joint interface J. The strength of the heat affected zone H is such that the first member 10 and the second member 20 are heat treated alloys (JIS standard 2000 series aluminum alloy (Al-Cu-Mg series alloy), JIS standard 6000 series aluminum alloy (Al -Mg-Si alloy), JIS standard 7000 series aluminum alloy (Al-Zn-Mg alloy)), it is smaller than the base metal, and is not heat-treatable alloy (JIS standard 1000 series aluminum alloy) In the case of (pure aluminum series), JIS standard 3000 series aluminum alloy (Al-Mn series alloy), JIS standard 5000 series aluminum alloy (Al-Mg series alloy), it is larger than the base material. Therefore, for example, when the first member 10 and the second member 20 are made of a heat treatment type alloy, the thickness on the inner peripheral side of the cylindrical portions 11 and 21 is higher than the strength at the outer peripheral thickness change points Q1 and Q2. The intensity at the change points P1 and P2 becomes smaller.

  Further, in the friction welding component 1 according to the present embodiment, the steep burrs 11a and 11b are formed on the first member 10 side, so that the shape factor α on the first member 10 side than the joint interface J is formed. However, it is 1.5 or more.

The shape factor α is also called a stress concentration factor, and is defined by the following equation, _where σ _max is the maximum stress and σ _n is the average stress in the cross section including the wall thickness change point P1.
α = σ _max / σ _n

The shape factor α ₀ when the butt weld joint of the wide strip 101 and the narrow strip 102 shown in FIGS. 3A and 3B receives the tensile force F can be calculated by the following equation. Are known.

  Since the cross-sectional shape of the notch by the burr on the first member 10 side with respect to the joining interface J approximates the shape of the butt weld joint shown in FIG. 3, the shape factor α on the first member 10 side with respect to the joining interface J. Can be calculated by the following equation.

As can be seen from the above equation, the shape factor α increases as the burr bottom angles θ _1a , θ _1b decrease, increases as the burr bottom radii R _1a , R _1b decrease, and the thickness t _{J at the} joint interface J increases. It gets bigger. For reference, Table 1 shows an example of specifications in which the shape factor α is rounded to 2.0.

  The notch coefficient β (= (fatigue strength in the absence of stress concentration) / (fatigue strength in the presence of stress concentration), which is an index of durability performance, increases as the stress concentration increases, that is, as the shape factor α increases. 4, the change rate Δβ of the notch coefficient β tends to decrease as the shape factor α increases, and the change rate Δα of the shape factor α and the notch coefficient β The ratio (= Δβ / Δα) with the change rate Δβ is 1 or less, and the graph shown in Fig. 4 shows that the material of the butt welded joint shown in Fig. 3 is JIS standard aluminum alloy 6061-T6 (JIS standard). 6000 series aluminum alloy (Al-Mg-Si series alloy), which has been subjected to quenching treatment after solution treatment and then artificial aging treatment).

  By the way, since the shape of the notch due to burrs slightly changes due to slight differences in tolerances, temperature changes, and friction welding conditions of the first member 10 and the second member 20, the shape factor α varies for each friction welding component 1. However, when the first member 10 and the second member 20 are made of JIS standard aluminum alloy 6061-T6, if the shape factor α is set to 2.0 or more, the variation in the shape factor α is notched. The effect on β is small. That is, if the friction welding is performed so that the shape factor α on the first member 10 side with respect to the joining interface J is 2.0 or more, the change rate Δβ of the notch coefficient β is reduced, so that there is an error in the friction welding conditions and the like. Even if such occurs, it is possible to reduce the variation in fracture strength (fatigue strength) at the joint, and it is possible to accurately grasp the magnitude of fracture strength at the joint.

  As described above, in the friction-welded component 1 according to the present embodiment, the degree of stress concentration in the notched portions by the burrs 11a and 11b on the first member 10 side is the burr portions 21a and 21b on the second member 20 side. Since it always becomes higher than the stress concentration degree in the notch portion due to, the stress concentration in the joint portion only needs to be considered on the first member 10 side. That is, according to the friction welded part 1, it is possible to reduce variations in strength, and in addition, it is possible to accurately grasp the magnitude of the strength, so that the design of the friction welded part can be streamlined. It becomes possible.

Incidentally, when the first member 10 and the second member 20 are made of a heat-treated alloy, the strength decreases as the joint interface J is approached. Therefore, at the thickness change points P1 and P2 on the inner peripheral side of the cylindrical portions 11 and 21, respectively. Is smaller than the strength at the wall thickness change points Q1, Q2. That is, when an unexpected load is applied, there is a high possibility that the destruction proceeds from the inner peripheral side of the cylindrical portions 11 and 21. Particularly in the present embodiment, the notch formed by the burr 11a formed on the inner peripheral side of the cylindrical portion 11 of the first member 10 is more than the notch formed by the burr 21a formed on the inner peripheral side of the cylindrical portion 21 of the second member 10. Therefore, when an unexpected load is applied, from the notch of the rising portion of the burr 11a (that is, near the thickness change point P1 on the inner peripheral side of the cylindrical portion 11 of the first member 10). Destruction is likely to progress. In this way, the burr bottom angle θ _1a of the burr 11a formed on the inner peripheral side of the cylindrical portion 11 and the burr bottom radius R _1a are used as the burr bottom angle θ _{2a of the} burr 21a formed on the inner peripheral side of the cylindrical portion 21. If it is smaller than the burr bottom radius R _2a , it is easy to specify the destruction mode.

Even if the outer diameter of the cylindrical portion 11 and the outer diameter of the cylindrical portion 21 are not equal, the burr bottom angle θ _1a and the burr bottom radius R _1a formed on the inner space side of the cylindrical portion 11 Although it can be made smaller than the burr bottom angle θ _2a and burr bottom radius R _2a formed on the inner peripheral side, the outer diameters of the cylindrical portions 11 and 21 are made equal to each other as in the present embodiment, and a step is formed on the inner peripheral surface. If provided, the burr bottom angle θ _1a and burr bottom radius R _1a formed on the inner peripheral side of the cylindrical portion 11 are changed to the burr bottom angle θ _2a and burr bottom radius R formed on the inner peripheral side of the cylindrical portion 21, respectively. _It tends to be smaller than _2a . Further, if the outer diameter of the cylindrical portion 11 is equal to the outer diameter of the cylindrical portion 21, there is no step between the outer peripheral surface of the cylindrical portion of the first member and the outer peripheral surface of the cylindrical portion of the second member. The work of excising the burrs 11b, 21b thus made can be easily performed.

Further, as shown in FIG. 5, the burrs 11 b and 21 b formed on the outer peripheral side of the joint portion may be cut out to smooth the outer peripheral surface of the joint portion. If the burr bottom angle θ _1a and burr bottom radius R _1a formed on the side are smaller than the burr bottom angle θ _2a and burr bottom radius R _2a formed on the inner peripheral side of the cylindrical portion 21, the burr 11b , 21b can be easily identified even after excision.

  Moreover, in this embodiment, while forming the 1st member 10 and the 2nd member 20 with the aluminum alloy 6061-T6 of JIS specification, the shape factor alpha by the side of the 1st member 10 rather than the joining interface J is 2.0 or more. Therefore, there is no variation in the notch coefficient β. That is, the fracture strength of the friction welded part 1 can be grasped more accurately.

In the above-described embodiment, the thickness t ₁ of the cylindrical portion 11 of the first member 10 before the friction welding is made smaller than the thickness t ₂ of the cylindrical portion 21 of the second member 20, so that the friction welding is performed. The area of the abutting surface 11c of the first member 10 and the secondary moment of the cross section are smaller than the area of the abutting surface 21c of the second member 20 and the secondary moment of the cross section before the friction welding. For example, FIG. ), By forming a thin portion 13 with a step on the tip of the cylindrical portion 11 of the first member 10 before the friction welding, the area of the abutting surface 11c of the first member 10 before the friction welding and The cross-sectional secondary moment may be smaller than the area of the abutting surface 21c of the second member 20 and the cross-sectional secondary moment before the friction welding. In this case, the thickness t ₁ of the cylindrical portion 11 of the first member 10 and the thickness t ₂ of the cylindrical portion 21 of the second member 20 may be the same.

  Even if it does in this way, since the cylindrical part 11 of the 1st member 10 fluidizes previously at the time of friction welding, although illustration is abbreviate | omitted, the burr | flash burr bottom angle formed in the 1st member 10 side, It is possible to make the burr bottom radius smaller than the burr bottom angle or burr bottom radius of the burr formed on the second member 20 side. Further, if the thin portion 13 is formed in the cylindrical portion 11 of the first member 10, it is not necessary to make the cylindrical portion 21 of the second member 20 thick over the entire length, so the weight of the friction welding component 1 is more than necessary. Will not increase.

Further, as shown in FIG. 6B, the first member before friction welding is formed by forming a thick portion 23 by providing a step at the tip of the cylindrical portion 21 of the second member 20 before friction welding. The area of the 10 abutting surfaces 11c and the secondary moment of the cross section may be smaller than the area of the abutting surface 21c of the second member 20 and the secondary moment of the cross section before the friction welding. In this case, the thickness t ₁ of the cylindrical portion 11 of the first member 10 and the thickness t ₂ of the cylindrical portion 21 of the second member 20 may be the same.

  Even if it does in this way, since the cylindrical part 11 of the 1st member 10 fluidizes previously at the time of friction welding, although illustration is abbreviate | omitted, the burr | flash burr bottom angle formed in the 1st member 10 side, It is possible to make the burr bottom radius smaller than the burr bottom angle or burr bottom radius of the burr formed on the second member 20 side. Moreover, if the thick part 23 is formed in the cylindrical part 21 of the second member 20, it is not necessary to make the cylindrical part 21 of the second member 20 thick over the entire length, so the weight of the friction welding component 1 is necessary. There is no increase.

Further, as shown in FIG. 6C, the tapered portion 14 is formed at the tip of the cylindrical portion 11 of the first member 10 before the friction welding, so that the first member 10 butt before the friction welding. The area of the surface 11c and the cross-sectional secondary moment may be smaller than the area of the abutting surface 21c of the second member 20 and the cross-sectional secondary moment before the friction welding. In this case, the thickness t ₁ of the cylindrical portion 11 of the first member 10 and the thickness t ₂ of the cylindrical portion 21 of the second member 20 may be the same.

  Even if it does in this way, since the cylindrical part 11 of the 1st member 10 fluidizes previously at the time of friction welding, although illustration is abbreviate | omitted, the burr | flash burr bottom angle formed in the 1st member 10 side, It is possible to make the burr bottom radius smaller than the burr bottom angle or burr bottom radius of the burr formed on the second member 20 side. Further, if the inclined portion 14 is formed at the tip of the cylindrical portion 11 of the first member, it is not necessary to make the cylindrical portion 21 of the second member 20 thick over the entire length, so the weight of the friction welding component 1 is increased. Does not increase more than necessary.

  In the above-described embodiment, the first member 10 and the second member 20 are made of the same material, and the area of the abutting surface 11 c of the first member 10 is made smaller than the area of the abutting surface 21 c of the second member 20. The cylindrical portion 11 of the first member 10 is fluidized first, but if the first member 10 is formed of a dissimilar metal having a lower strength (particularly high temperature strength) than the second member 20, the abutting surfaces 11c and 21c Even if the area is the same, the cylindrical portion 11 of the first member 10 can be fluidized first. That is, the burr bottom angle of the burr formed on the first member 10 side is also omitted, although the first member 10 is formed of a dissimilar metal having a strength (particularly high temperature strength) lower than that of the second member 20. It becomes possible to make it smaller than the burr bottom angle of the burr formed on the second member 20 side. Specifically, for example, if the first member 10 is made of an aluminum alloy and the second member 20 is made of a copper alloy having a higher high temperature strength than the aluminum alloy, the areas of the abutting surfaces 11c and 21c are the same. However, the cylindrical portion 11 of the first member 10 can be fluidized first.

  Even when the first member 10 and the second member 20 are made of the same kind of metal, the first member is used when there is a clear strength difference (particularly a high temperature strength difference) due to a difference in the metal manufacturing process. Ten cylindrical portions 11 can be fluidized first. Specifically, for example, the first member 10 is made of a 2000 series aluminum alloy (Al-Cu-Mg series alloy (geralmine or the like) which is a heat treatment type alloy) or a 4000 series aluminum alloy (Al-Si which is a non-heat treatment type alloy). If the second member 20 is made of a 6000 series aluminum alloy having a high temperature strength higher than that of a 2000 series or 4000 series aluminum alloy, the area of the abutting surfaces 11c and 21c is the same. Since the cylindrical portion 11 of the first member 10 can be fluidized first, the burr bottom angle and the burr bottom radius of the burr formed on the first member 10 side are set to the second member although illustration is omitted. The burr bottom angle and burr bottom radius of the burr formed on the 20 side can be made smaller.

  Also, the first member 10 can be fluidized first by setting the first member 10 to a temperature higher than that of the second member 20. For example, even if the first member 10 and the second member 20 are made of the same material and the areas of the abutting surfaces 11c and 21c are the same, the first member 10 is moved from the second member 20 in the friction process. However, if the temperature is too high, the first member 10 can be fluidized first. As a result, although not shown, the burr bottom angle of the burr formed on the first member 10 side is set to the second member 20 side. It becomes possible to make it smaller than the burr bottom angle of the formed burr. In order to raise the temperature of the first member 10 higher than that of the second member 20, for example, the second member 20 is air-cooled or water-cooled during the friction process, or the jig that chucks the first member 10 is insulated. Then, heat transfer from the first member 10 to the jig may be prevented, or the jig may be heated with a heating wire, a burner or the like.

  Further, in the above-described embodiment, the case where the end surfaces of the hollow cylindrical portions 11 and 21 are the abutting surfaces 11c and 21c is illustrated, but for example, as illustrated in FIG. The solid column portion 25 may be provided, and the end surface thereof may be used as the abutting surface 25c. If the first member 10 and the second member 20 are made of the same material, the tip of the cylindrical portion 11 of the first member 10 will be fluidized before the column portion 25 of the second member 20. Although not shown, the burr bottom angle and burr bottom radius of the burr formed on the cylindrical part 11 are smaller than the burr bottom angle and burr bottom radius of the burr formed on the outer peripheral side of the column part 25.

  Further, as shown in FIG. 7B, not only the second member 20 but also the first member 10 may be provided with a solid column portion 15, and the end surface thereof may be used as the abutting surface 15 c. When the first member 10 and the second member 20 are made of the same material, the column portion 15 of the first member 10 has a smaller diameter than the column portion 25 of the second member 20 (that is, the abutting surface 15c). The area is made smaller than the area of the abutting surface 25c). If it does in this way, since the front-end | tip part of the pillar part 15 of the 1st member 10 will buckle and fluidize ahead of the pillar 25 of the 2nd member 20, although illustration is abbreviate | omitted, it forms in the pillar part 15 The burr bottom angle and burr bottom radius of the burr formed are smaller than the burr bottom angle and burr bottom radius of the burr formed on the outer peripheral side of the column portion 25.

(A) is sectional drawing which shows the friction welding part which concerns on embodiment of this invention, (b) is sectional drawing which shows the 1st member and 2nd member before friction welding. It is an enlarged view of the X part of (a) of FIG. It is a schematic diagram for demonstrating the calculation formula of a shape factor. It is a graph which shows an example of the relationship between a shape factor and a notch coefficient. It is an expanded sectional view which shows the state which excised the burr | flash on the outer peripheral side. (A)-(c) is sectional drawing which shows the modification of the 1st member and the 2nd member before friction welding. (A) And (b) is sectional drawing which shows the other modification of the 1st member and the 2nd member before friction welding.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Friction welding part 10 1st member 11 Cylindrical part 11a, 11b Burr 11c Abutting surface 20 Second member 21 Cylindrical part 21a, 21b Burr 21c Butting surface J Joining interface

Claims (16)

A friction welding component formed by friction welding the first member and the second member,
The friction welding part, wherein a notch formed by the burr formed on the first member side is smaller than a notch formed by the burr formed on the second member side. A friction welding component formed by friction welding the cylindrical portion of the first member and the cylindrical portion of the second member,
Friction welding, wherein a notch formed by a burr formed on the inner peripheral side of the cylindrical portion of the first member is smaller than a notch formed by a burr formed on the inner peripheral side of the cylindrical portion of the second member. parts.   The friction welding component according to claim 2, wherein the thickness of the cylindrical portion of the first member before friction welding is smaller than the thickness of the cylindrical portion of the second member before friction welding.   The friction welding part according to claim 3, wherein an outer diameter of the cylindrical portion of the first member is equal to an outer diameter of the cylindrical portion of the second member.   The first member and the second member are made of JIS standard aluminum alloy 6061-T6, and the shape factor on the first member side with respect to the bonding interface is 2.0 or more. The friction welding part as described in any one of Claims 4 thru | or 4.   The friction welding part according to any one of claims 1 to 4, wherein a burr bottom angle of a burr formed on the first member side is an acute angle.   5. The area of the abutting surface of the first member before friction welding is smaller than the area of the abutting surface of the second member before friction welding. 6. Friction welding parts.   The cross-sectional secondary moment of the abutting surface of the first member before friction welding is smaller than the cross-sectional secondary moment of the abutting surface of the second member before friction welding. The friction welding part as described in any one.   The friction welded part according to any one of claims 1 to 4, wherein the strength of the first member is lower than the strength of the second member. A method of friction welding the first member and the second member,
When the first member and the second member are butted while rotating relative to each other, the first member is fluidized first, so that a notch is formed by a burr formed on the abutting surface side of the first member. Is made smaller than a notch formed by a burr formed on the second member side. A method of friction welding the cylindrical portion of the first member and the cylindrical portion of the second member,
When the cylindrical portion of the first member and the cylindrical portion of the second member are abutted while rotating relative to each other, the inner periphery of the cylindrical portion of the first member is fluidized first. A friction welding method, wherein a notch formed by a burr formed on the side is made smaller than a notch formed by a burr formed on an inner peripheral side of the cylindrical portion of the second member.   The first member is fluidized first by setting the thickness of the cylindrical portion of the first member before friction welding to be smaller than the thickness of the cylindrical portion of the second member before friction welding. The friction welding method according to claim 11.   The friction welding method according to any one of claims 10 to 12, wherein the first member is fluidized first by setting the first member to a temperature higher than that of the second member. .   The first member is fluidized first by making the area of the abutting surface of the first member before friction welding smaller than the area of the abutting surface of the second member before friction welding. The friction welding method according to any one of claims 10 to 12.   By setting the second moment of section of the butt surface of the first member before friction welding to be smaller than the second moment of section of the butt surface of the second member before friction welding, the first member first The friction welding component according to any one of claims 10 to 12, wherein the friction welding component is fluidized.   13. The first member is fluidized first by forming the first member with a material having lower strength than the second member. The friction welding method according to item.

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