JP2010069520A - Joining method of metallic member and joining device used for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joining method of metallic members capable of preventing occurrence of welding distortion which causes quality deterioration when instantaneously diffusion-joining first and second metallic members with a large current, and also to provide a joining device used for the same. <P>SOLUTION: A first opposite face 10a, a first opposite wall part 10, and a first fitting part 11 are preliminarily formed at a gear 1. A second opposite face 12a, a second opposite wall part 12, and a second fitting part 13 are preliminarily formed at a clutch cone. The clutch cone is externally fitted to the gear and the second fitting part 13 is held in a fittable state at the first fitting part 11. The gear 1 and the clutch cone 2 are pressurized to allow the first and second opposite wall faces 10, 12 to approach with each other, and the large current is instantaneously applied. The second fitting part 13 is fitted to the first fitting part 11 and the inner circumferential part and outer circumferential part of the second fitting part 13 are joined to the inner circumferential part and outer circumferential part of the first fitting part 11, respectively. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for joining metal members and a joining apparatus therefor, and in particular, the quality deterioration due to welding distortion can be achieved by instantaneously diffusing and joining the opposing wall portions of the first and second metal members orthogonal to each other with a large current. It relates to technology that can be prevented.

Conventionally, as disclosed in Patent Document 1, a transmission gear manufacturing method in which a synchro clutch cone is externally fitted to a transmission main gear, and an inner peripheral surface of the clutch cone is joined to the main gear by electron beam welding. A technique in which a portion close to the tooth portion of the clutch cone is joined to the main gear by electric resistance spot welding before electron beam welding has been put into practical use.
However, in this manufacturing method, since electric resistance welding and electron beam welding are used in combination, it is necessary to perform the welding in two steps, so that the production efficiency is reduced and two types of electric resistance welding and electron beam welding are performed. Since welding equipment is required, the equipment cost becomes expensive.

Accordingly, the applicant of the present application has developed a technique for manufacturing a gear member for a transmission by a welding technique (also referred to as mash joining) in which a metal member is welded by instantaneously energizing a large amount of electricity accumulated in a capacitor. In this manufacturing method, as shown in FIGS. 9 and 10, the pressure force is instantaneously increased and the upper electrode 103 is applied in a state where the clutch cone 102 is held on the cylinder portion 101 of the main gear 100 so as to be externally fitted and pressurized. Then, a large current is applied to the lower electrode 104 instantaneously, and the inner peripheral surface of the clutch cone 102 is diffusion bonded to the outer peripheral surface of the cylindrical portion 101 using heat generated by electric resistance.
JP 2004-11816 A

  In the transmission gear joined as described above, as shown in FIG. 11, due to thermal distortion during welding, the cylindrical portion 101 of the main gear 100 is deformed toward the inner diameter side, and the end surface 101 a of the cylindrical portion 101 is axially centered. It is deformed into an inclined shape inclined with respect to the orthogonal plane. Therefore, since the inner peripheral surface of the cylinder part 101 must be corrected by polishing, the number of polishing steps is increased, and it takes a great deal of cost to polish and correct a large deformation of 20 to 30 μm. In addition, if the end face 101a of the cylinder portion 101 is incorporated into the transmission as it is without being modified, the wear of the end face portion proceeds, causing play and noise.

  An object of the present invention is to provide a method and apparatus for joining metal members capable of preventing the occurrence of welding distortion that causes deterioration in quality when the first and second metal members are diffusion-bonded instantaneously with a large current. It is to be.

The metal member joining method of the present invention (Claim 1) is to diffusely join an annular first metal member and a second metal member fitted on the first metal member to the first metal member by electric resistance heat generation. In the joining method to be performed, a first opposing wall portion having a first opposing surface perpendicular to the axis of the first metal member and facing the second metal member, and an annular formed on the first opposing wall portion And a second opposing wall portion having a second opposing surface perpendicular to the axial center of the second metal member and opposing the first opposing portion, and a second opposing wall portion. An annular second fitting portion that is formed on the opposing wall portion and can be fitted to the first fitting portion is formed in advance,
A first step of externally fitting a second metal member to the first metal member and holding the second fitting portion in a state in which the second fitting portion can be fitted to the first fitting portion; and the first and second opposing wall portions, While pressurizing the first and second metal members so as to approach each other, a current is instantaneously applied to the first and second metal members, and the second fitting portion is fitted to the first fitting portion. The second step of joining the inner peripheral portion and the outer peripheral portion of the second fitting portion to the inner peripheral portion and the outer peripheral portion of the first fitting portion, respectively.

You may employ | adopt the following various structures as said structure of this invention.
(1) The first fitting portion is a concave groove having a cylindrical first inner peripheral surface and a first outer peripheral surface that are concentric with the axis of the first metal member, and the second fitting portion is a second metal. It is a convex part which has the cylindrical 2nd inner peripheral surface and 2nd outer peripheral surface which are concentric with the axial center of a member, and the 1st inner peripheral surface is the 1st overlap amount rather than the 2nd inner peripheral surface in the state before joining The first outer peripheral surface is formed with a smaller diameter than the second outer peripheral surface by a second overlap amount (Claim 2).

(2) The first fitting portion is a convex portion having a cylindrical first inner peripheral surface and a first outer peripheral surface concentric with the axis of the first metal member, and the second fitting portion is a second metal. It is a ditch | groove which has the cylindrical 2nd internal peripheral surface and 2nd outer peripheral surface which are concentric with the axial center of a member, and the 1st internal peripheral surface is the 1st overlap amount rather than the 2nd internal peripheral surface in the state before joining. The first outer peripheral surface is formed to have a larger diameter than the second outer peripheral surface by a second overlap amount (Claim 3).

(3) The first overlap amount is set larger than the second overlap amount.
(4) The axial center position of the second metal member relative to the first metal member is set by bringing the first and second opposing wall surfaces into contact with each other in the joined state.
(5) The first metal member is a gear member of a manual transmission mechanism, and the second metal member is a clutch cone.

According to a seventh aspect of the present invention, there is provided the joining apparatus for a metal member in which a first metal member having an annular shape and a second metal member externally fitted to the first metal member are diffusion-bonded to the first metal member by electric resistance heat generation. The first metal member has a first opposed wall portion having a first opposed surface orthogonal to the axial center and opposed to the second metal member, and an annular first fitting formed on the first opposed wall portion. A second opposing wall having a second opposing surface perpendicular to the axis of the second metal member and opposing the first opposing part; and a second opposing wall part An annular second fitting portion that is formed and can be fitted to the first fitting portion in advance,
The first metal member is externally fitted with a second metal member, and the first fitting portion is provided with holding means for holding the second fitting portion in a state where the second fitting member can be fitted, and the first and second opposing wall portions are The first and second metal members are pressurized so as to approach each other, current is applied to the first and second metal members, and the second fitting portion is fitted to the first fitting portion to perform the first fitting. A pressurizing energization means for joining the inner peripheral portion and the outer peripheral portion of the second fitting portion to the inner peripheral portion and the outer peripheral portion of the second fitting portion, respectively, is provided.

  According to the present invention (Claim 1), a first fitting portion is formed in advance on a first opposing wall portion having a first opposing surface orthogonal to the axis of the first metal member, and the second metallic member A second fitting portion is formed in advance on a second facing wall portion having a second facing surface orthogonal to the axis, and a current is instantaneously applied by pressurizing the first and second metal members, Since the second fitting portion is fitted to the first fitting portion, and the inner peripheral portion and the outer peripheral portion of the second fitting portion are joined to the inner peripheral portion and the outer peripheral portion of the first fitting portion, respectively, the axial center Since the first and second opposing wall portions that have the first and second opposing surfaces in the orthogonal direction and are difficult to deform in the radial direction are joined, the quality deterioration due to the radial deformation of the first and second metal members is reduced. It can be surely prevented. Therefore, it is not necessary to perform a polishing process for correcting the welding distortion, so that the manufacturing cost can be reduced.

  According to the seventh aspect of the present invention, a joining device having the same effect as the present invention can be obtained.

  The best mode for carrying out the present invention will be described based on examples.

  As shown in FIG. 1, a gear 1 as a first metal member to be joined and a clutch cone 2 as a second metal member are shown. The gear 1 is a driven gear provided in a manual transmission for an automobile, and the clutch cone 2 is a component that is welded and joined to the gear 1 as one component of the synchromesh (synchronous meshing mechanism). As the material for the gear 1 and the clutch cone 2, carburized and quenched steel such as SCr steel is used.

  The gear 1 is formed in a disc shape having a predetermined thickness in the direction of the axis A and has a main body 3 having a tooth portion 3a on the outer periphery thereof, and a cylindrical shape protruding from the upper end of the main body 3 in the axial direction. And a cylindrical portion 4. The gear 1 is formed with an insertion hole 5 penetrating in the axial direction over the main body portion 3 and the cylindrical portion 4. When the transmission is assembled, the main shaft (not shown) slides into the insertion hole 5. It is inserted so as to be movable or rollable via a bearing.

  On the other hand, the clutch cone 2 has a main body portion 6 and a cone portion 7 protruding from the upper end of the main body portion 6 toward the axis B. A tooth portion 6 a is formed on the outer peripheral portion of the main body portion 6. The cone portion 7 is formed in a tapered shape whose outer peripheral surface becomes smaller in diameter toward the upper end side. A through hole 8 that can be loosely fitted to the cylindrical portion 4 of the gear 1 is formed in the lower 2/3 portion of the clutch cone 2, and the upper 1/3 portion of the clutch cone 2 has a larger diameter than the through hole 8. The hole 9 is formed. During the synchronization operation of the transmission, the tapered outer peripheral surface of the cone portion 7 is brought into pressure contact with the inner peripheral surface of the synchro ring (not shown) to synchronize the rotational speed.

  On the upper surface portion of the body portion 3 of the gear 1, a first opposing wall portion 10 having a first opposing surface 10 a orthogonal to the axis A and facing the clutch cone 2, and the first opposing wall portion 10 The formed annular first fitting portion 11 is formed in advance. The first opposing wall portion 10 is a wall portion formed to have a thickness of several millimeters on the inner diameter side portion of the upper surface portion of the main body portion 3. The first fitting portion 11 is formed of a concave groove having a rectangular cross section having a cylindrical inner peripheral surface and an outer peripheral surface that are concentric with the axis A.

  The clutch cone 2 has a second opposing wall portion 12 that has a second opposing surface 12 a that is orthogonal to the axis B and that opposes the first opposing surface 10 a of the gear 1, and is formed on the second opposing wall portion 12. In addition, an annular second fitting portion 13 that can be fitted to the first fitting portion 11 is formed in advance. The 2nd fitting part 13 consists of a convex part with a rectangular cross section which has the cylindrical inner peripheral surface and outer peripheral surface which are concentric with the axial center B. As shown in FIG. The depth of the first fitting portion 11 is formed to be, for example, about 0.2 to 0.4 mm larger than the protruding height of the second fitting portion 13.

As shown in FIG. 5, the cylindrical portion 4 of the gear 1 has a smaller diameter than the through hole 8 of the clutch cone 2, and is between the outer peripheral surface of the cylindrical portion 4 of the gear 1 and the inner peripheral surface of the through hole 8. For example, a gap G of about 1 to 2 mm is formed. This is to prevent current from flowing from the inner peripheral surface of the through hole 8 to the cylindrical portion 4 of the gear 1 during energization described later.
Further, as shown in FIG. 5, the inner diameter D1i of the first fitting portion 11 is formed larger than the inner diameter of the second fitting portion D2i by a first overlap amount Gi (for example, 0.15 mm), The outer diameter D1o of the first fitting portion 11 is formed smaller than the outer diameter D2o of the second fitting portion 13 by a second overlap amount Go (for example, 0.15 mm). Said 1st, 2nd overlap amount Gi, Go is a fastening allowance of welding joining, and also is a current passage through which welding current flows at the start of welding as will be described later.

  Next, a metal member joining apparatus for joining the gear 1 and the clutch cone 2 will be described. As shown in FIGS. 2 to 4, the joining device 20 instantaneously energizes the welding target portion of the gear 1 and the clutch cone 2 with a large amount of electricity stored in a large-capacity capacitor, thereby generating a gear by electric resistance heat generation. 1 is a device that diffuses and joins the clutch cone 2 to the clutch cone 2. The above joining method is also called “mash joining”.

  The joining device 20 includes a support base 21, a centering member 23 that is vertically fixed to the center of the upper end portion of the support base 21 with bolts 22, and an annular shape that is fixed to the upper surface of the support base 21 with a plurality of bolts 24. A lower electrode 25, a slide 26 supported by a frame (not shown) so as to be movable up and down, and opposed to the support 21 from above, an upper electrode 27 fixed to the lower surface of the slide 26, and a lower end of the upper electrode 27 A position regulating ring 28 fixed to the periphery, an air cylinder (not shown) that can drive the slide 26 up and down and can be driven to press downward with a pressure of about 10 tons, an upper electrode 27 and a lower electrode 25 And a power supply device 29 with a built-in capacitor capable of supplying a large current of about 320 kA to the objects to be joined (gear 1 and clutch cone 2).

  The centering member 23 is configured so that a part thereof is fitted in the insertion hole 5 of the gear 1 without a gap so as to center the gear 1 at a predetermined position. On the upper end of the lower electrode 25, a mounting surface 25a for receiving and supporting the lower end portion of the gear 1 by surface contact and for allowing a welding current to flow is formed. The upper electrode 27 has an annular electrode portion 27a having substantially the same diameter as the clutch cone 2, and the lower surface of the annular electrode portion 27a abuts on the upper end of the cone portion 7 of the clutch cone 2 by surface contact to transmit the applied pressure. In addition, an abutment surface 27b for forming a welding current is formed.

  The position restricting ring 28 is fixed to the inner peripheral side portion of the contact surface 27b in the lower end surface of the annular electrode portion 27a. This position regulating ring 28 is a member for positioning the clutch cone 2 at a coaxial position where the axis B of the clutch cone 2 coincides with the axis A of the gear 1, and the upper electrode 27 contacts the clutch cone 2. In the state, the position restricting ring 28 is configured to fit into the hole 9 of the cone portion 7 without a gap. Note that the gap G shown in FIG. 5 is formed between the cylindrical portion 4 of the gear 1 and the clutch cone 2 in a state where the axis B of the clutch cone 2 is aligned with the axis A of the gear 1.

Next, a metal member joining method for joining the gear 1 and the clutch cone 2 formed in advance in the shape shown in FIG. 1 using the joining device 20 will be described.
In the first step, as shown in FIG. 2, the gear 1 is set in the joining device 20, the gear 1 is mounted on the mounting surface 25a of the lower electrode 25, and the lower end surface of the gear 1 is in surface contact with the mounting surface 25a. At the same time, the centering member 23 positions the gear 1 by centering.

  Next, in the second step, as shown in FIG. 3, the clutch cone 2 is set on the gear 1, the clutch cone 2 is loosely fitted to the cylindrical portion 4 of the gear 1, and the first fitting portion 11 is fitted. The second fitting portion 13 is opposed so as to be fitted, the slide 26 is lowered, and the contact surface 27b at the lower end of the upper electrode 27 is brought into surface contact with the upper end of the tapered portion 7 of the clutch cone 2 and the position restricting ring 28 is provided. By fitting inside the taper portion 7, the clutch cone 2 is centered and positioned so that the axis B of the clutch cone 2 is coaxial with the axis A of the gear 1. In this state, the clutch cone 2 is pressed against the gear 1 by the pressing force F1 (for example, about 1 ton) of the slide 26.

  Next, in the second step, as shown in FIG. 4, the pressing force F2 of the slide 26 is rapidly increased to about 8 tons to bring the clutch cone 2 closer to the gear 1 and at the same time, the power supply device 29 is activated. Thus, a large current is passed through the upper electrode 27, the clutch cone 2, the gear 1 and the lower electrode 25 instantaneously. Then, due to the electric resistance heat generated when the welding current flows from the second fitting portion 13 to the inner peripheral portion and the outer peripheral portion of the first fitting portion 11, and the pressure of about 8 tons acting from the slide 26. The second fitting portion 13 is fitted into the first fitting portion 11, and the inner and outer peripheral portions of the first fitting portion 11 and the inner and outer peripheral portions of the second fitting portion 13 are plastic. Flow occurs and rapid diffusion bonding is performed at a temperature below the melting point.

  As a result, as shown in FIGS. 4 and 6, the first fitting portion 11 and the second fitting portion 13 are diffusion-bonded and integrated at two locations of the inner peripheral portion and the outer peripheral portion. In addition, surplus metal protrudes into the gap between the bottom surface of the first fitting portion 11 and the second fitting portion 13 to become a burr 30. Further, the second opposing wall portion 12 of the clutch cone 2 is brought into surface contact with the first opposing wall portion 10 of the gear 1 so that the axial position of the clutch cone 2 with respect to the gear 1 is accurately determined.

The operation and effect of the bonding apparatus 20 and the bonding method described above will be described.
The gear 1 and the clutch cone 2 are pressurized to apply a large current instantaneously, the second fitting part 13 is fitted to the first fitting part 11, and the inner and outer peripheral parts of the first fitting part 11 In addition, in order to join the inner peripheral portion and the outer peripheral portion of the second fitting portion 13 respectively, the first and second opposing surfaces 10a, 12a in the direction orthogonal to the axial center are respectively provided, and the first, first, which are not easily deformed in the radial direction. Since the second opposing wall portions 10 and 12 are joined together, it is possible to manufacture a high-quality gear member by reliably preventing a deterioration in quality due to the radial deformation of the gear 1 and the crack cone 2. Therefore, it is not necessary to perform a polishing process for correcting the welding distortion, so that the manufacturing cost can be greatly reduced.

  Since the gear 1 and the clutch cone 2 are joined in a coaxially positioned state via the centering member 23 and the position regulating ring 28, the coaxiality of the gear 1 and the clutch cone 2 can be ensured. In the embodiment, the support base 21, the centering member 23, the position regulating ring 28, the upper electrode 25, the slide 26, and the like correspond to “holding means”. Further, the support base 21, the lower electrode 25, the upper electrode 27, the slide 26, an air cylinder (not shown) that drives the slide 26 downward, the power supply device 29, and the like correspond to the “pressurizing energizing means”. .

Here, the example which changes the said Example partially is demonstrated.
1] In the above embodiment, the inner diameter side tightening allowance Gi and the outer diameter side tightening allowance Go of the first and second fitting portions 11 and 13 are set to be equal, but the amount (volume) of the metal that plastically flows during joining. The inner diameter side tightening allowance Gi may be set larger than the outer diameter side tightening allowance Go so that the inner diameter side is equal to the outer diameter side. For example, as shown in FIG. 7, it is particularly desirable to set D1i · Gi = D1o · Go when the radial widths of the first and second fitting portions 11 and 13 are set large.
If the amount (volume) of metal that plastically flows during welding is set to be equal on the inner diameter side and the outer diameter side, the current flowing on the inner diameter side and the current flowing on the outer diameter side can be made substantially equal, and the bonding quality It is because it can raise.

  2] As shown in FIG. 7, on the inner diameter side and the outer diameter side of the second fitting portion 13, escape grooves 13 a and 13 b for escaping excess metal at the time of joining may be formed. By allowing excess metal to escape into the escape grooves 13a and 13b, the adhesion between the first and second opposing surfaces 10a and 12a can be enhanced.

3] In the above-described embodiment, the first fitting portion 11 is constituted by a concave groove and the second fitting portion 13 is constituted by a convex portion. On the contrary, as shown in FIG. 11 A of joint parts may be comprised by a convex part, and 13 A of 2nd fitting parts may be comprised by a ditch | groove.
4] In the above embodiment, the inner and outer peripheral surfaces of the first and second fitting portions 11 and 13 are formed on a cylindrical surface coaxial with the axis, but the first and second fitting portions 11 and 13 are formed. At least one of the inner peripheral surface and the outer peripheral surface may be formed in a tapered surface close to a cylindrical surface coaxial with the axis.
In addition, those skilled in the art can implement the present invention in a form in which various modifications are added.

It is sectional drawing of the gear and clutch cone which concern on the Example of this invention. It is sectional drawing of the support stand of a joining apparatus, a centering member, a lower electrode, and a gear. It is sectional drawing which shows the state which set the gear and the clutch cone to the joining apparatus. It is sectional drawing which shows the state which joined the gear and the clutch cone with the joining apparatus. It is a principal part expanded sectional view before joining of a gear and a clutch cone. It is a principal part expanded sectional view after joining of a gear and a clutch cone. FIG. 6 is a diagram corresponding to FIG. 5 according to a modified example. FIG. 6 is a diagram corresponding to FIG. 5 according to another modification. It is sectional drawing of the state which set the gear and the clutch cone to the joining apparatus of a prior art. FIG. 10 is a cross-sectional view of a state where the gear of FIG. 9 and the clutch cone are joined. FIG. 10 is an enlarged cross-sectional view of the main part of the gear and clutch cone after joining in FIG. 9.

Explanation of symbols

1 Gear (first metal member)
2 Clutch cone (second metal member)
DESCRIPTION OF SYMBOLS 10 1st opposing wall part 10a 1st opposing surface 11 1st fitting part 12 2nd opposing wall part 12a 2nd opposing surface 13 2nd fitting part 20 Joining device 23 Centering member 28 Position control ring

Claims (7)

In a joining method in which an annular first metal member and a second metal member externally fitted to the first metal member are diffusion-bonded to the first metal member by electric resistance heat generation,
A first opposing wall portion having a first opposing surface perpendicular to the axis of the first metal member and facing the second metal member, and an annular first fitting formed on the first opposing wall portion And forming a part in advance,
A second opposing wall portion having a second opposing surface that is orthogonal to the axial center of the second metal member and that opposes the first opposing surface, and the first fitting is formed on the second opposing wall portion. An annular second fitting part that can be fitted to the part is formed in advance,
A first step of externally fitting a second metal member to the first metal member and holding the second fitting portion in a state in which the second fitting portion can be fitted to the first fitting portion;
The first and second metal members are pressurized so that the first and second opposing wall surfaces come close to each other, and an electric current is instantaneously applied to the first and second metal members, and the second fitting portion is subjected to the second. A second step of fitting the fitting portion to join the inner peripheral portion and the outer peripheral portion of the second fitting portion to the inner peripheral portion and the outer peripheral portion of the first fitting portion, respectively;
A method for joining metal members, comprising:   The first fitting portion is a concave groove having a cylindrical first inner peripheral surface and a first outer peripheral surface that are concentric with the axis of the first metal member, and the second fitting portion is an axis of the second metal member. A convex portion having a cylindrical second inner peripheral surface and a second outer peripheral surface that are concentric with the center, and the first inner peripheral surface has a larger diameter than the second inner peripheral surface by a first overlap amount in a state before joining. The metal member joining method according to claim 1, wherein the first outer peripheral surface is formed to have a smaller diameter than the second outer peripheral surface by a second overlap amount.   The first fitting portion is a convex portion having a cylindrical first inner peripheral surface and a first outer peripheral surface concentric with the axis of the first metal member, and the second fitting portion is a shaft of the second metal member. A concave groove having a cylindrical second inner peripheral surface and a second outer peripheral surface that are concentric with the center, and the first inner peripheral surface is smaller in diameter than the second inner peripheral surface by a first overlap amount in a state before joining. 2. The method for joining metal members according to claim 1, wherein the first outer peripheral surface is formed to have a larger diameter than the second outer peripheral surface by a second overlap amount.   The metal member joining method according to claim 2 or 3, wherein the first overlap amount is set to be larger than the second overlap amount.   4. The axial center position of the second metal member with respect to the first metal member is set by bringing the first and second opposing wall surfaces into contact with each other in the joined state. Metal member joining method.   The metal member joining method according to claim 1, wherein the first metal member is a gear member of a manual transmission mechanism, and the second metal member is a clutch cone. In a joining apparatus that diffuses and joins an annular first metal member and a second metal member fitted on the first metal member to the first metal member by electric resistance heat generation,
A first opposing wall portion having a first opposing surface perpendicular to the axis of the first metal member and facing the second metal member, and an annular first fitting formed on the first opposing wall portion And forming a part in advance,
A second opposing wall portion having a second opposing surface that is orthogonal to the axial center of the second metal member and that opposes the first opposing surface, and the first fitting is formed on the second opposing wall portion. An annular second fitting part that can be fitted to the part is formed in advance,
A holding means for holding the second metal member on the first metal member and holding the second fitting portion in a state in which the second fitting portion can be fitted to the first fitting portion;
The first and second metal members are pressurized so that the first and second opposing wall surfaces approach each other, current is applied to the first and second metal members, and the second fitting portion is applied to the first fitting portion. And pressurizing energization means for joining the inner peripheral portion and the outer peripheral portion of the second fitting portion to the inner peripheral portion and the outer peripheral portion of the first fitting portion, respectively,
A metal member joining apparatus characterized by the above.