JP2010131622A - Device for assembling metal component and method used for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress reduction of separating load and increase fatigue limit even when metal components are formed of a material of steel or the like having ductility in assembling the metal components capable of easily preventing face displacement of joining faces using unevenness of a broken face and achieving reduction of cost and weight by using a plurality of members split by cracking that become one ring shaped component fastened by a fastening member like a connecting rod of an engine. <P>SOLUTION: When separated rod body 4 and cap 5 are temporarily assembled in finish processing, a nut is clamped by a nut runner 12 while imparting ultrasonic vibration by an ultrasonic vibrating means 13. Accordingly, the joining faces generate heat and become softened to be fastened in an almost completely matched state only by pressing the members with slight pressing force through Blaha effect and reduction of friction between the members. The reduction of the separating load due to reduction of a contact area between the members is suppressed to increase the fatigue limit. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an apparatus and method for assembling metal parts, and in particular, after the metal parts are divided into a plurality of rings from a ring-like material made of a ductile material, such as an engine connecting rod, It is used in the case of a configuration in which another member is held in the ring-shaped portion by being combined with each other and fastened by a fastening member. For example, the present invention relates to a temporary assembly for finishing.

  Like the connecting rod of the engine, a plurality of members are fastened by a fastening member to form one ring (ring) -like part, and the plurality of members are not separately prepared, but are originally integrated. By using what was divided into a plurality of parts by so-called cracking, using the unevenness of the fractured surface, without using positioning pins etc., it is possible to easily prevent surface displacement of the joint surface, Conventionally, metal parts that realize cost reduction and weight reduction have been proposed.

As such a metal part, Patent Document 1 discloses that a half mandrel is fitted in a through hole of a steel connecting rod and a wedge is driven into the half mandrel to break it. It is shown that the optimum breaking state can be obtained regardless of experience by managing the expansion speed or expansion acceleration of the hole.
JP 2005-144560 A

  The above-mentioned Patent Document 1 discloses a management method of how to accurately divide at the time of breakage. By the way, although a metal part can be divided relatively neatly in the case of a sintered material, the following problems arise when it is made of a material having ductility such as steel. First, as shown in FIG. 9, the irregularities do not completely coincide with the deformation of the fracture surface. FIG. 9 shows the steel connecting rod. In the enlarged fracture surface, the unevenness is enlarged 10 times with respect to the surface direction. As shown in the enlarged view, the corresponding protrusions and recesses of the cap are not completely fitted into the recesses and protrusions of the rod body. Next, chip-like extras such as burrs and straws are generated. Furthermore, as shown in FIG. 10, a decrease in the circularity of the ring shape causes a deviation in the straightness of a hole through which a fastening member such as a bolt is inserted. That is, at the time of breakage, a tensile force in the direction of the arrow A is generated in the divided portion of the ring (ring), and the diameter D of the ring (ring) is contracted. For this reason, the bolt hole is displaced inward in the radial direction by ΔD, for example, 60 μm.

  Therefore, when the cap is bolted to the rod body, the fastening force (the axial force of the bolt) is used to correct the deformation of the uneven surface, compress the chip (crush), correct the straightness, etc. There is a problem that the separation load between the members to be used and fastened is reduced, and the fatigue limit is reduced.

  SUMMARY OF THE INVENTION An object of the present invention is to assemble a metal part that can match a joint surface (ductile fracture surface) when assembling divided annular metal parts and suppress a decrease in separation load due to a decrease in contact area between members. And to provide a method.

  The metal part assembling apparatus of the present invention is divided into a plurality of parts from a ring-shaped state made of a ductile material, and then combined with each other and fastened with a fastening member. ) In an assembling apparatus for temporarily assembling a metal part having a separate member held in the shape part, for example, in finishing, includes ultrasonic vibration means for applying ultrasonic vibration to the metal part at the time of fastening. It is characterized by that.

  The metal part assembling method of the present invention is a combination of a breaking step of dividing a metal part formed in a ring shape with a ductile material into a plurality of parts, and the divided members. And a fastening step of pressing the joining surface and fastening with a fastening member while applying ultrasonic waves to one member.

  According to the above configuration, like a connecting rod of an engine, a plurality of members are fastened by a fastening member to form a ring-shaped part, and the plurality of members are separately prepared. Rather, by using what was originally molded in one piece but divided into a plurality of parts by so-called cracking, it is easy to use the unevenness of the fracture surface, without using positioning pins etc. In the case of metal parts that prevent surface slippage and realize cost reduction and weight reduction, when the metal parts are sintered materials, they can be divided relatively neatly, but they are made of a ductile material such as steel. Holes through which fastening members such as bolts can be inserted due to the deformation of the fracture surface where unevenness does not completely match, extra chips are generated, and the ring has a reduced roundness. True of Every time deviation occurs in. For this reason, at the time of fastening by the fastening member, the fastening force (axial force of the bolt, etc.) is used for correcting deformation of the uneven surface, compressing chips, correcting the straightness, etc., and a member to be fastened The separation load between them decreases, and the fatigue limit decreases. Therefore, in the present invention, when the divided members are temporarily assembled, for example, in finishing, ultrasonic vibration is applied by ultrasonic vibration means. After finishing from the temporary assembly, the member is divided again, and the main assembly is performed by holding another member in the ring-shaped portion (in the case of the connecting rod, in the engine assembly process). Mounted on the crankshaft).

  Therefore, due to the Braha effect due to the ultrasonic vibration and the reduction of friction between the members, the joint surfaces (ductile fracture surfaces) generate heat and soften only by pressing the members with a slight pressing force, and they are well adapted and closely adhered to each other. Will do. As a result, the joint surface (ductile fracture surface) can be fastened in a state of nearly perfect coincidence, the reduction in the separation load due to the reduction in the contact area between the members can be suppressed, and the fatigue limit can be increased.

  Furthermore, in the metal component assembling apparatus of the present invention, the ultrasonic vibration means includes first ultrasonic vibration means for propagating ultrasonic waves from the ring-shaped outer diameter direction, and the ring (ring). And a second ultrasonic vibration means for propagating ultrasonic waves from the axial direction.

  According to said structure, a 1st ultrasonic vibration means propagates an ultrasonic wave in the pressing direction (fastening direction) of the said joint surface, and a 2nd ultrasonic vibration means transmits an ultrasonic wave from the side of the said joint surface. Propagate.

  Therefore, the joint surface (ductile fracture surface) is better adapted, and the joint surface (ductile fracture surface) can be fastened in a state of close to perfect coincidence, further suppressing the decrease in the separation load due to the decrease in the contact area between the members. be able to.

  Further, in the metal part assembling apparatus of the present invention, the metal parts are divided into two in half, and the first ultrasonic vibration means is arranged at a central position (90 ° position) of the half crack (180 °). ), And is arranged in a shifted manner.

  According to the above configuration, when the metal parts are divided into two half-breaks, the first ultrasonic vibration means for propagating ultrasonic waves from the ring-shaped outer diameter direction includes the half-break. If it is offset from the center position (90 ° position) of (180 °), torsional vibration is generated on the joint surface (ductile fracture surface).

  Therefore, the joint surface (ductile fracture surface) is softened better, and the joint surface (ductile fracture surface) can be fastened in a state of close to perfect coincidence. It can be further suppressed.

  Furthermore, the metal component assembling apparatus of the present invention further includes a sonic vibration means for applying a vibration lower than the ultrasonic wave, and before the fastening, the at least one member divided by the sonic vibration means. Chip removal is performed by applying the sonic vibration.

  According to said structure, the chip produced by the said ductility when the said metal component is divided | segmented by the said cracking can be removed with a sound wave vibration means.

  Therefore, the joint surface (ductile fracture surface) can be fastened in a state that is closer to perfect match, and the reduction in the separation load due to the reduction in the contact area between the members can be further suppressed.

  In the metal part assembling apparatus of the present invention, the sound wave vibrating means is attached to an ultrasonic wave propagation member common to the ultrasonic wave vibrating means.

  According to said structure, the ultrasonic wave propagation member for ultrasonic wave propagation and the diaphragm for chip removal can be shared.

  Furthermore, in the metal component assembling apparatus of the present invention, the metal component is an engine connecting rod.

  According to the above configuration, in the case of the connecting rod of the engine, the demand for cost reduction and weight reduction is severe, and steel cracking is preferable, but the precision and separation load are also demanded. It can implement especially suitably.

  Further, the metal part assembling method of the present invention includes a measuring step of measuring the contracted diameter of the ring (ring) in the divided portion after the breaking step, and expanding the divided portion in response to the measurement result. And a correction step of correcting the contraction by diameter.

  According to the above configuration, a tensile force is generated in the split part of the ring (ring) in the breaking step, and the diameter of the ring (shrink) is contracted. Therefore, the contracted diameter is measured, and the measurement result is By correcting so as to increase the diameter accordingly, the inclination of the joint surface (ductile fracture surface) can be eliminated, and the straightness of the hole through which a fastening member such as a bolt is inserted can be increased. As a result, the joint surface (ductile fracture surface) can be fastened in a state that is closer to perfect coincidence.

  Furthermore, the metal part assembling method of the present invention is characterized by further comprising a brushing step of removing the chips by brushing the fracture surface of the divided portion before the fastening step.

  According to the above configuration, when metal parts formed in a ring shape with a material having ductility are separated by being separated from each other, chips are generated in the divided parts due to the ductility, and thus are removed by brushing. Thereby, the said joint surface (ductile fracture surface) can be fastened in the state near a perfect match.

  The metal part assembling apparatus and method according to the present invention is a ring-shaped part formed by fastening a plurality of members with a fastening member, such as a connecting rod of an engine. By using what is molded in one piece and divided into a plurality of parts by so-called cracking, the unevenness of the fracture surface can be used to easily prevent misalignment of the joint surface, realizing cost reduction and weight reduction. When the metal part is made of a material having ductility such as steel, ultrasonic vibration is given by ultrasonic vibration means when the divided members are assembled.

  Therefore, due to the Braha effect and reduced friction between the members, the joint surfaces (ductile fracture surfaces) are heated and softened only by pressing the members together with a slight pressing force, and they are well adapted to adhere to each other. . As a result, the joint surface (ductile fracture surface) can be fastened in a nearly perfect state, a reduction in separation load due to a reduction in contact area between members can be suppressed, and a fatigue limit can be increased.

[Embodiment 1]
FIG. 1 is a cross-sectional view showing the structure of an assembling apparatus 1 according to the first embodiment of the present invention. This assembling apparatus 1 is an assembling apparatus for temporarily assembling a connecting rod 2 of an engine, which is a metal part formed in a ring shape from a material having ductility. FIG. 2 is a front view of the connecting rod 2, and FIG. 3 is a cross-sectional view as seen from the section line III-III in FIG.

  The connecting rod 2 is forged as a single piece by steel, and once divided into a rod body 4 and a cap 5 by so-called cracking at a portion of the notch 3, and then fastened with a bolt 6 and a nut 7, By utilizing the unevenness of the fracture surface, it is possible to easily prevent the displacement of the joint surface without using positioning pins or the like, thereby realizing cost reduction and weight reduction. In the breaking process, the technique of the above-mentioned Patent Document 1 can be used, and the half mandrel can be fitted into the through-hole 8 and the wedge can be driven into the half mandrel for breaking. .

  And this connecting rod 2 fastens the said rod main body 4 and the cap 5 in the state which inserted the crankshaft which is another member in the through-hole 8 which is the said ring (ring) -shaped part (it was made to hold), Further, before the final assembly of the engine in which the piston pin is inserted into the other through-hole 9, the assembly apparatus 1 performs the temporary assembly as described above in the finishing process in the through-hole 8. is there. Adjustment is performed as will be described later by the temporary assembly, and after the finishing process is performed, it is disassembled again and sent to the main assembly process together with the bolt 6 and the nut 7 used for the temporary assembly.

  Referring to FIG. 1, it should be noted that in the assembling apparatus 1 of the present embodiment, the connecting rod 2 divided into the rod body 4 and the cap 5 is mounted on a base 11 and a pair of nuts. In performing the temporary assembly by fastening the nut 7 to the bolt 6 by the runner 12, an ultrasonic vibration means 13 for applying ultrasonic vibration to the portion of the through hole 8 is provided. The ultrasonic vibration means 13 includes an ultrasonic vibrator 14 that generates the ultrasonic vibration, a plate 15 that propagates the generated ultrasonic waves from the inner peripheral side of the through hole 8 to the rod body 4 and the cap 5. It is configured with. The plate 15 is formed in a truncated cone shape so as to fit in the through-hole 8 and cope with a change in inner diameter due to fastening.

  When the connecting rod 2 is replaced, the ultrasonic vibration means 13 is retracted from the base 11 as indicated by a virtual line, and is positioned by a worker on a jig or the like (not shown) so as to be positioned on the rod body 4. Is mounted on the base 11, and the cap 5 is mounted on the base 11 so that the joint surfaces (ductile fracture surfaces) coincide with each other, the bolt 6 is inserted into the bolt hole, and the nut 7 is temporarily tightened. Then, after the ultrasonic vibration means 13 is moved onto the base 11 and the rod body 4 is pressed by the pressing member 16 to which the ultrasonic vibration means 13 is connected, the ultrasonic vibration means 13 is Contact the rod body 4 and the cap 5. Thereafter, the nut 7 is fastened by the nut runner 12 while applying the ultrasonic vibration by the ultrasonic vibration means 13.

  With such a configuration, in the connecting rod 2 made of a ductile material, the rod body 4 and the cap 5 which are separated from each other in the breaking process are integrally assembled (fastened) with the bolt 6 and the nut 7. By applying ultrasonic vibration, the joint surface (ductile fracture surface) is heated and softened only by pressing the rod body 4 and the cap 5 with a slight pressing force due to the Braha effect and reduction of friction between members. And they will get used to each other and adhere to each other. As a result, the deformation of the concavo-convex surface in the fracture surface (joint surface) generated in the breaking process, the compression of chips, and the straightness of the bolt hole are corrected, and the joint surface (ductile fracture surface) is completely formed. It becomes possible to conclude in a state close to coincidence. Further, the axial force (fastening force) of the bolt 6 is hardly used for such correction of the fracture surface (joint surface). In this way, it is possible to suppress a decrease in the separation load due to a decrease in the contact area between the rod body 4 and the cap 5 and increase the fatigue limit.

  In particular, in the case of the connecting rod 2 of the engine, the demands for cost reduction and weight reduction are severe, and steel cracking is suitable, but since the precision and separation load are also demanded, the present invention is particularly suitably implemented. can do.

  FIG. 4 is a diagram for explaining an assembly process according to an embodiment of the present invention using the assembly apparatus 1 configured as described above. In the breaking step of Step S1, the connecting rod 2 forged as an integral object is once divided into the rod body 4 and the cap 5 using the steel cracking technique of Patent Document 1 described above. Subsequently, in the measurement process of step S2, the shrinkage ΔD (see FIG. 10) of the diameter D generated in the divided portion is measured by the breaking process. A caliper, a three-dimensional measuring device, or the like can be used for the measurement.

  Using the measurement result, in the correction step of step S3, correction for the shrinkage ΔD is performed using a correction jig 21 as shown in FIG. The straightening jig 21 holds and fixes the rod body 4 and the cap 5 from the outer side of the through-hole 8 by a guide pin 22 erected on a base (not shown), and is inserted into the through-hole 8. One of the divided portions is fixed by the piece 23, and the other is expanded by the moving piece 24 that can be displaced away from the fixed piece 23 to correct the shrinkage ΔD. By measuring the amount of shrinkage ΔD of the diameter D of the through-hole 8 generated in the breaking process in this way and correcting it so as to expand the diameter according to the measurement result, the inclination of the joint surface (ductile fracture surface) 25 is corrected. The straightness of the bolt hole 26 can be increased. Thereby, it is possible to fasten the joint surface (ductile fracture surface) 25 in a state closer to perfect match.

  Subsequently, in the brushing step of step S4, the fracture surface (joint surface) 25 is brushed to remove chips. By performing this brushing process, the joint surface (ductile fracture surface) 25 can be fastened in a state closer to perfect match.

  Thereafter, in the fastening process by temporary assembly in step S5, the rod body 4 and the cap 5 are fastened while applying ultrasonic vibration as described above. In the finishing process in step S6, the finishing process in the through hole 8 is performed. Is called. Thereafter, in the re-disassembling process of step S7, the rod body 4 and the cap 5 are unfastened, and the bolt 6 and the nut 7 are combined and sent to the main assembly process of step S8 to be assembled to the crankshaft. It is done.

[Embodiment 2]
FIG. 6 is a side view showing the structure of the assembling apparatus 31 according to the second embodiment of the present invention. The assembling apparatus 31 is similar to the assembling apparatus 1 described above, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. The same applies to the connecting rod 2 to be assembled. It should be noted that in the assembling apparatus 31, as the ultrasonic vibration means, first ultrasonic vibration means for propagating ultrasonic waves from the outer diameter direction of the through hole 8 which is the ring-shaped portion of the connecting rod 2. 32 and second ultrasonic vibration means 33 for propagating ultrasonic waves from the axial direction of the through hole 8 (perpendicular to the first ultrasonic vibration means 32).

  On the base 34, a floating substrate 37 that can be slightly swung around the axis of the pin 35 is supported by a pin 35 and a guide shaft 36, and a jig 38 provided on the floating substrate 37, The connecting rod 2 is mounted on 39. One of the jigs 38 is provided with a mounting piece 38a for supporting the head 4a of the rod body 4 in the connecting rod 2 and a contact piece 38b with which the head 4a abuts. , L-shaped. When the first ultrasonic vibration means 32 applies ultrasonic vibration from the outer side of the contact piece 38b, the pressing direction (fastening direction) of those joint surfaces from the rod body 4 side to the cap 5 side. ) And the rod body 4 and the cap 5 easily come into close contact with each other when the nut runner 12 tightens the nut 7.

  On the other hand, an elevating board 42 is supported by the guide shaft 36 so as to be movable up and down, and a plate 40 is elastically supported by a spring 41 on the lower surface of the elevating board 42. Therefore, when the elevating substrate 42 is lowered with respect to the connecting rod 2 mounted on the jigs 38 and 39, the plate 40 is pressed with a constant pressing force by the spring 41, and by the pin 35 and the spring 41, The floating substrate 37 and the plate 40 are parallel to each other, and the plate 40 is in close contact with the connecting rod 2. When ultrasonic vibration is generated by the second ultrasonic vibration means 33 in this state, ultrasonic waves are applied to the connecting rod 2 via the plate 40 from the side of the joint surface between the rod body 4 and the cap 5. Propagated to promote close contact between the rod body 4 and the cap 5.

  By configuring in this way, the joint surface (ductile fracture surface) is more familiar (can be further softened), and the joint surface (ductile fracture surface) can be fastened in a state close to perfect match. The decrease in the separation load due to the decrease in the contact area between the cap 5 and the cap 5 can be further suppressed. Preferably, the joint surface (ductile fracture surface) can be softened more effectively by operating the ultrasonic vibration means 32 and 33 alternately.

[Embodiment 3]
FIG. 7 is a plan view showing the structure of an assembling apparatus 51 according to the third embodiment of the present invention. This assembling apparatus 51 is similar to the assembling apparatus 31 described above, and corresponding portions are denoted by the same reference numerals, and description thereof is omitted. In FIG. 7, for simplification of the drawing, a configuration below the floating substrate 37 and a configuration above the plate 40 are omitted. It should be noted that, in this assembling apparatus 51, in the connecting rod 2, the rod body 4 and the cap 5 are divided into two in half around the through hole 8, whereas the first Is disposed (offset) by a reference sign ΔD from the center position (90 ° position: indicated by the diameter line D) of the half crack (180 °).

  With such an offset arrangement, torsional vibration is generated on the joint surface (ductile fracture surface), the joint surface (ductile fracture surface) is softened better, and the joint surface (ductile fracture surface) becomes more flexible. It can be fastened in a state close to perfect coincidence, and the reduction in the separation load due to the reduction in the contact area between the rod body 4 and the cap 5 can be further suppressed.

[Embodiment 4]
FIG. 8 is a side view showing the structure of the assembling apparatus 61 according to the fourth embodiment of the present invention. This assembling apparatus 61 is also similar to the assembling apparatus 31 described above, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that in this assembling apparatus 61, the second ultrasonic vibration means 33 is replaced by a sound wave vibration means 63 that gives a vibration that is lower than the ultrasonic wave and has a large amplitude. The sound wave vibration means 63 can be realized by a vibrator or the like that generates vibration by rotating a weight.

  With this configuration, before the rod body 4 and the cap 5 are fastened, the sound wave vibration is applied to at least one of the divided rod body 4 and the cap 5 by the sound wave vibration means 63. Therefore, chip removal can be performed. As a result, the brushing step in step S4 can be omitted. Preferably, the second ultrasonic vibration means 33 and the sound wave vibration means 63 are attached to the plate 40, so that the axial direction of the through hole 8 (perpendicular to the first ultrasonic vibration means 32). The ultrasonic wave is also propagated, and the plate 40 can be shared by the second ultrasonic vibration means 33 and the sound wave vibration means 63.

  Here, in Japanese Patent Application Laid-Open No. 2007-185731, a screw member is brought into contact with an action portion of a piezoelectric actuator and is fastened by ultrasonic vibration, so that a mark corresponding to a driver or the like is not provided on a screw head. Thus, there is shown a screw fastening method that prevents aesthetic improvement and undesired loosening operation, and also shows that a plurality of screw members are simultaneously brought into contact with the action portion of the piezoelectric actuator. . However, in this prior art, ultrasonic waves are applied to the screw itself, and the ultrasonic energy is consumed for turning the screw, whereas in the present invention, the ultrasonic energy is applied to the joint surface (ductile fracture surface). ) Is used to match 25 and is quite different.

It is sectional drawing which shows the structure of the assembly apparatus which concerns on the 1st Embodiment of this invention. It is a front view of a connecting rod. It is sectional drawing seen from the cut surface line III-III of FIG. It is a figure for demonstrating the assembly process of one Embodiment of this invention using the said assembly apparatus. It is a figure for demonstrating the correction method of the deformation | transformation by the fracture | rupture of the said connecting rod. It is a side view which shows the structure of the assembly apparatus which concerns on the 2nd Embodiment of this invention. It is a top view which shows the structure of the assembly apparatus which concerns on the 3rd Embodiment of this invention. It is a side view which shows the structure of the assembly apparatus which concerns on the 4th Embodiment of this invention. It is a figure for demonstrating the mode of a deformation | transformation of the torn surface by the fracture | rupture of the said connecting rod. It is a figure for demonstrating the mode of the shift | offset | difference of the straightness of the fastening bolt hole by the fracture | rupture of the said connecting rod.

Explanation of symbols

1, 31, 51, 61 Assembly device 2 Connecting rod 4 Rod body 5 Cap 6 Bolt 7 Nut 8, 9 Through hole 11 Base 12 Nut runner 13 Ultrasonic vibration means 14 Ultrasonic vibrator 15 Plate 16 Pressing member 21 Correction treatment Tool 23 Fixed piece 24 Moving piece 25 Joint surface (ductile fracture surface)
26 Bolt hole 32 First ultrasonic vibration means 33 Second ultrasonic vibration means 34 Base 37 Floating board 38, 39 Jig 40 Plate 41 Spring 42 Lifting board 63 Sound wave vibration means

Claims (9)

In an apparatus for assembling a metal part in which a separate member is held in the annular part by being combined with each other and fastening with a fastening member after being divided into a plurality from a state formed in an annular shape with a ductile material,
An apparatus for assembling a metal part, comprising ultrasonic vibration means for applying ultrasonic vibration to the metal part at the time of fastening.   The ultrasonic vibration means includes first ultrasonic vibration means for propagating ultrasonic waves from the annular outer diameter direction, and second ultrasonic vibration means for propagating ultrasonic waves from the annular axial direction. The metal part assembling apparatus according to claim 1, wherein the metal part assembling apparatus is configured.   3. The metal part assembly according to claim 2, wherein the metal part is divided into two in half, and the first ultrasonic vibration means is displaced from a central position of the half crack. apparatus. Further comprising a sound wave vibration means for applying vibration lower than the ultrasonic wave,
The chip removal is performed by applying the sonic vibration to the at least one of the divided members by the sonic vibration means before the fastening. Assembling apparatus for metal parts as described.   5. The metal component assembling apparatus according to claim 4, wherein the sonic vibration means is attached to an ultrasonic wave propagation member common to the ultrasonic vibration means.   The metal part assembling apparatus according to claim 1, wherein the metal part is a connecting rod of an engine. A breaking step of dividing a metal part formed in a ring shape from a ductile material into a plurality of parts;
A method of assembling a metal part, comprising: a step of combining the divided members with each other, pressing a joint surface while applying ultrasonic waves to at least one member, and fastening with a fastening member. After the breaking step, a measuring step for measuring the contracted diameter of the ring in the divided portion;
The metal part assembling method according to claim 7, further comprising a correcting step of correcting the contraction by expanding the diameter of the divided portion in response to the measurement result.   The method of assembling a metal part according to claim 7 or 8, further comprising a brushing step of brushing a fracture surface of the divided portion to remove chips before the fastening step.

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