JP4694873B2 - Press-fit joining method and press-fit joined parts - Google Patents

Description

  The present invention relates to a press-fit joining method and press-fit joining parts between members constituting a metal element part.

  2. Description of the Related Art Conventionally, when manufacturing metal element parts used for automobiles and the like, for example, as a resistance welding method, a method of joining members by a spot welding method or a projection welding method has been performed. Further, according to the eye joint manufacturing method, a bead is formed on the insertion side base portion of the pipe portion to be inserted into the pipe connection hole, or a lip is formed on the inlet side periphery of the pipe connection hole so that the eye portion and the pipe portion are connected. A technique for resistance welding is also disclosed (for example, Patent Document 1).

  The main resistance of the resistance welding method is the lap resistance welding method, and all are joined by forming a molten structure called a nugget at the joint. In this lap resistance welding, in order to strengthen the welding, as a result of increasing the number of nuggets, thermal deterioration of the joint base material and influence on dimensional accuracy are inevitable. In addition, the formation of the beads or lips complicates the manufacturing process and requires post-processing.

Japanese Patent Laid-Open No. 7-40058 JP 2001-353628 A

  On the other hand, the present applicant has previously proposed a press-fit joint structure (Patent Document 2). In this press-fit joining structure, as shown in FIG. 13, the shaft body 92 is press-fit and joined to the hole 94 of the plate 90 using a jig. This jig has a lower die 96 made of chrome copper as an electrode and an upper die 98 provided with a cylindrical hole 97 in the lower part, while a plate 90 is disposed on the upper part of the lower die 96, and the upper die The upper portion of the shaft body 92 is plunged and held in the hole portion 97 of 98 to perform press-fit joining.

  In press-fit joining, the shaft body 92 is pressed into the hole portion 94 of the plate 90 with a predetermined pressure, and the two members are energized through the electrodes to generate electrical resistance heat at the joint portion. The shaft body 92 is press-fitted into the hole portion 94, a bonding interface is formed at the joint portion between the joint surface portion of the shaft body 92 and the inner wall surface portion of the hole portion 94, and this bonding is a solid-phase bonding. is there.

  Now, in the above press-fit joining, a considerable current is required to perform press-fitting together with energization between members. For this reason, the electrical resistance at the contact portion between the member and the electrode is reduced, and the current is efficiently supplied to the joined portion. There is a need to. In this case, an upper die 98 is attached to the shaft body 92 as an electrode. However, in order to detachably place the shaft body 92 in the hole 97 of the upper die 98, the side surface of the shaft body 92 is provided. It is necessary to form a slight gap between the portion and the inner wall surface of the hole 97 of the upper mold 98.

  For this reason, energization from the upper mold 98 to the shaft body 92 is performed on a part of the upper surface portion and the side surface portion of the shaft body 92. At this time, when the shaft body is thick and the outer diameter is large, the contact area between the upper surface portion of the shaft body and the upper mold 98 is wide, which is convenient for energization, but the shaft body is thin and the outer diameter is small. In this case, the contact area between the shaft body and the upper mold 98 becomes narrow, and the support of the shaft body is not stable. If this contact area is small, the electrical resistance of the contact portion between both increases and the amount of heat generation also increases, and in addition, the influence of the electrical resistance of the shaft body itself cannot be ignored, and the current supply to the joint is hindered. There's a problem.

  Also, conventionally, in projection welding on galvanized steel sheets, etc., the range of proper welding conditions is narrow, which affects nugget formation, and electrode tips are consumed significantly due to galvanization, and the electrode life is reduced. In addition, there is a problem that a large current is required and sputtering is likely to occur. For this reason, there are many problems in the projection welding method or spot welding method, particularly in the joining of members that have been plated.

  The present invention has been made in view of the above-mentioned problems, and is a press-fit joining method and a press-fit joined component that are easily and well-bonded, are excellent in mass productivity and reliability, and are excellent in strength. The purpose is to provide.

  In order to solve the above technical problem, the press-fit joining method according to the present invention includes a first member 2 having a hole 3 in which an inner wall surface portion having the same cross-section of the press-fit portion is formed, as shown in FIG. A predetermined press-fitting allowance is provided between the hole and the shaft-shaped second member 4 in which a joint surface portion extending in the axial direction is formed, and the first member 2 is replaced with the first electrode 6. The side surface of the second member 4 is mechanically sandwiched between the second electrodes 8 made up of a plurality of electrode pieces 9 and directed into the hole 3 of the first member 2. The second member 4 held between the two members is pressed with a predetermined pressure, and an electric current is generated between the two members to generate electric resistance heat at the joint between the two members. Press-fit to form a joint interface at the joint between the joint surface of the second member and the inner wall surface of the hole, and this joint is solid Is that the bonding between the.

  As shown in FIG. 12, the press-fitting method according to the present invention includes a cylindrical first member 52 having a hole 53 in which an inner wall surface having the same cross-section of the press-fitted portion is formed, and the hole 53. A side portion of the first member 52 is formed of a plurality of electrode pieces 59 using a shaft-like second member 54 provided with a predetermined press-fitting allowance therebetween and having a joint surface portion extending in the axial direction. While one electrode 58 is mechanically clamped, the side surface portion of the second member 54 is mechanically clamped by a second electrode 64 including a plurality of electrode pieces 62 and 63, and the first member 52 The second member 54 held in the hole 53 is pressed with a predetermined pressure, and an electric current is generated between the two members to generate electric resistance heat at the two parts. A member is press-fitted into the hole, and a joint between the joint surface of the second member and the inner wall surface of the hole is formed. If the interface to form, and resides in that the bonding of the solid state of this joint.

  In the press-fitting method according to the present invention, a hole portion having a larger diameter than that of the hole portion is provided in the surface portion of the first electrode so as to communicate with the hole portion of the first member.

  In the press-fitting method according to the present invention, an insulating positioning member 84 that can move up and down is disposed in the hole of the first electrode, and the hole of the first member is engaged with the positioning member. Positioning.

  In the press-fitting method according to the present invention, the shape of the sandwiching portion of the electrode piece in the second electrode is formed to be the same as the shape of the side surface portion of the second member. That is, the entire or a part of the sandwiching portion of the electrode piece is in contact with the side surface portion of the member.

  The press-fit joining method according to the present invention is configured such that the second electrode can be moved while the second member is held and the second member can be positioned and held at a predetermined position. .

  The press-fit joining method according to the present invention is provided with a pressing portion 46 capable of pressing the end surface portion of the second member in the axial direction on the electrode piece of the second electrode.

  In the press-fitting method according to the present invention, the number of electrode pieces of the second electrode is two or three, and the second electrode is a part of the second electrode on an end surface portion in the axial direction of the second member. The third electrode 10 is provided.

  As shown in FIG. 10, the press-fitting method according to the present invention is provided with a pressing electrode portion 71 above the electrode piece of the second electrode, and a predetermined electrode is provided between the pressing electrode portion 71 and each of the electrode pieces. Support electrode portions 72 and 73 for maintaining a distance and supplying current to the electrode pieces are provided, and the upper portion of the second member 4 is held by the pressing electrode portion 71 so that it can be pressed. This is to pinch the vicinity of the lower part of the second member 4.

  The press-fit joining method according to the present invention is to electrically cut off between the pressing electrode portion and the upper part of the second member.

  The press-fit joining method according to the present invention is that the surface of the first member or the second member is plated.

  The press-fit joining method according to the present invention is that the galvanizing, alloying galvanizing, electrogalvanizing or alloy galvanizing is performed as the plating.

  Moreover, the press-fitting component according to the present invention is manufactured by any of the press-fitting methods described above, and the second member is joined to the hole of the first member.

  According to the press-fitting method according to the present invention, the first member is disposed on the surface portion of the first electrode, while the side surface portion of the second member is mechanically formed by the second electrode including a plurality of electrode pieces. While sandwiching and pressing the second member sandwiched in the hole of the first member at a predetermined pressure, energizing between both of these members to generate electrical resistance heat at the joint of both, Since this is a solid-phase joining obtained by press-fitting the second member into the hole, the electrical resistance between the electrode and the member is reduced during energization, and the second electrode is successfully removed from the second electrode. A current is supplied to the member, and the second member is stably held so that it can be press-fitted into the hole with high accuracy, and can be quickly joined in a simple process, resulting in excellent mass productivity and economy. The interface is cleaned, bonding is performed well, and the strength is excellent. In addition, since this joining method is a solid state joining, there is no occurrence of spatter and a good working environment is obtained, and there is no thermal deterioration of the electrodes and joints, and the durability of the electrodes and the finishing accuracy of the members are good. There is an effect.

  In addition, according to the press-fitting method according to the present invention, since the surface portion of the first electrode is provided with a hole portion having a larger diameter than the hole portion in communication with the hole portion of the first member, In addition, when the contact between the first member and the first electrode becomes unstable when the periphery of the hole of the first member is deformed in the press-fitting direction, the spark generated at this contact portion This has the effect of preventing explosions.

  Further, according to the press-fitting method according to the present invention, the positioning member is disposed in the hole portion of the first electrode, and the positioning member is positioned by engaging the hole portion of the first member. Therefore, there is an effect that the positioning of the first member can be performed accurately and easily.

  Further, according to the press-fitting method according to the present invention, the side surface portion of the first member is mechanically sandwiched by the first electrode composed of a plurality of electrode pieces, while the side surface portion of the second member is the plurality of electrodes. A second electrode made of a piece is mechanically sandwiched, and the second member sandwiched in the hole of the first member is pressed with a predetermined pressure, and both members are energized by energizing them. In the case where the electrical resistance heat is generated at the joint portion and the second member is press-fitted into the hole portion to effect solid-phase joining, the same effect as described above can be obtained, and the first member is cylindrical As described above, since it is configured to be sandwiched by a plurality of electrode pieces, as described above, it is excellent in mass productivity, economical efficiency, easy manufacturing in a simple process, excellent in strength, and good finishing accuracy. is there.

  According to the press-fitting method according to the present invention, since the whole or a part of the sandwiching portion of the electrode piece comes into contact with the side surface portion of the second member, the electrical resistance and the heat generation amount of the contact portion between the electrode and the member Therefore, there is an effect that energization can be satisfactorily performed, high-precision joining can be performed, and the durability of the electrode and the quality of the member are excellent without being affected by heat on the surface of the electrode and the member.

  In addition, according to the press-fitting method according to the present invention, the second electrode can be moved and positioned and held at a predetermined position while the second member is held, so that the electrode can be used for multiple functions. This is effective because it is efficient and the accuracy of the press-fitting position is improved.

  Further, according to the press-fitting method according to the present invention, since the pressing portion capable of pressing the end surface portion of the second member in the axial direction is provided on the electrode piece of the second electrode, in addition to the side surface portion of the second member. As a result, the electrical resistance is further reduced due to the contact of the upper surface portion, and the second member can be pressed to contribute to the reduction of the number of parts.

  According to the press-fitting method according to the present invention, the number of electrode pieces of the second electrode is two or three, and the third electrode is provided on the end surface portion of the second member. The electrical resistance is reduced, and there is an effect that an efficient joining can be performed with less electrical loss.

  Further, according to the press-fitting method according to the present invention, the supporting electrode portion is provided between the pressing electrode portion and each electrode piece, and the upper portion of the second member is held by the pressing electrode portion so as to be pressed. Therefore, the vicinity of the lower part of the second member is sandwiched, so that the second member can be stably supported even when the second member is long, and the press-fitting can be performed satisfactorily. .

  In addition, according to the press-fitting method according to the present invention, since the electrical connection between the pressing electrode part and the upper part of the second member is electrically interrupted, the second member is long and has high electrical resistance such as stainless steel, Or even if it is a case of a slim shape, there exists an effect that press-fit joining can be performed favorably.

  According to the press-fitting method according to the present invention, even if the surface of the first member or the second member is plated, an alloy chemical reaction between the electrode and the plating occurs due to less thermal influence. Therefore, the durability of the electrode is enhanced, and the surface of the member is well maintained, and there is an effect that a high-quality bonded part can be obtained without adversely affecting the plating.

  According to the press-fit joining method according to the present invention, since the hot dip galvanizing, the alloyed hot dip galvanizing, the electrogalvanizing or the galvanizing alloy is performed as the plating, the above-mentioned plating is also applied to the practical plating member. The same effect as the case can be obtained.

  Further, according to the press-fitting joint component according to the present invention, since the second member is manufactured by the press-fitting method according to any one of the above and the second member is joined to the hole of the first member, the hole is accurately obtained. In addition, it can be press-fitted into a joint, and can be joined quickly in a simple process, providing excellent mass productivity and economy. Also, the joining interface is cleaned and the joining is performed well and the strength is excellent. Since the joining is performed at this point, there is no effect on the electrodes, and there is no effect of thermal deterioration of the joining portion, and the finishing accuracy is good.

  Embodiments of press-fitting according to the present invention will be described below with reference to the drawings. 1 and 2 show a mechanism for press-fitting and joining a plate 2 and a shaft body 4 provided with a hole 3 as a workpiece using a press-fitting device. The shaft body 4 may be rod-shaped (solid) or cylindrical (hollow). In the description relating to each of the embodiments below, the components having the same reference numerals are assumed to have the same contents, and repeated description will be omitted.

  The press-fitting device includes a press-fitting mechanism having an electrode for energizing between the plate 2 and the shaft body 4, a moving mechanism for sandwiching the shaft body between the electrodes and moving it to a predetermined position, and the shaft body 4 can be pressed. It has a press mechanism. This press mechanism is provided in a normal resistance welding machine. Further, the electrode includes a thick plate-like lower electrode 6 on which the plate 2 can be placed, an upper electrode 8 divided into two electrode pieces 9, 9 holding the shaft body 4, and the shaft body 4. The material is made of chrome copper. The pressing electrode 10 is electrically connected to the upper electrode 8 and functions as a part thereof.

  The upper electrode 8 is mounted on a moving mechanism, and the shaft body 4 is transported to a predetermined position by the moving mechanism while being held by the upper electrode 8 and is positioned, held and fixed. When the shaft body 4 is press-fitted, the upper electrode 8 can be lowered by the up-and-down movement function of the moving mechanism. The press mechanism presses the pressing electrode 10 and lowers the shaft body 4 together with the applied pressure.

  The plate 2 has a predetermined thickness, the hole 3 provided in the plate 2 has a circular shape with a constant cross-sectional diameter, and the inner wall surface of the hole 3 is perpendicular to the plate surface of the plate 2. Is formed. The shaft body 4 is columnar and has a cylindrical side surface portion 12, a flat upper surface portion 14, and a lower surface portion 13. The outer diameter (diameter) of the joint surface portion 5 of the shaft body 4 is slightly larger than the diameter of the hole portion 3 of the plate 2, and the press-fitting allowance is the difference between them. By this press-fitting allowance, the outer peripheral portion of the joint surface portion 5 of the shaft body 4 is rubbed in contact with the inner wall surface portion of the hole portion 3 of the plate 2 to form a joint interface, and press-fit joining over the entire circumference is performed.

  The lower electrode 6 has a flat surface portion 7 on which the plate 2 is placed and supported, and a cylindrical hole portion 15 is provided near the center of the surface portion 7. The plate 2 is arranged such that the hole 3 is substantially aligned with the center of the hole 3 above the hole 15. The size (diameter) of the hole 15 is slightly larger than that of the shaft body 4. This hole portion 15 is for forming the clearance because the periphery of the hole 3 of the plate 2 is deformed in the press-fitting direction when the shaft member is press-fitted and joined to the plate 2. This is to prevent the shaft 4 from passing through the hole 3 and coming into direct contact with the lower electrode 6 to cause explosions and the like.

  The hole 15 prevents sparks, explosions, and the like generated at the contact portion when the contact between the plate 2 and the lower electrode 6 becomes unstable due to the load applied to the plate 2. In particular, since a spark or the like is likely to be generated around the lower portion of the hole 3, this is prevented. In general, the plate 2 may not be in close contact with the lower electrode 6 in an ideal shape. If the hole 15 is present, the effect of the escape is combined and the periphery of the hole 15 is compared with the plate 2. Good contact and good current flow can be achieved, and therefore, sparks and the like are reduced, and consumption of the lower electrode 6 is reduced. Further, the hole 15 can be used for positioning the plate 2 by arranging the following positioning member 84. The same effect can be obtained for all the holes 15 of the lower electrodes 6 according to the following embodiments.

  The upper electrode 8 is held by a moving mechanism, and the moving mechanism mechanically holds the side surface portion 12 of the shaft body 4 with two electrode pieces 9 and 9 together with a predetermined pressing force, and is in a state of holding it Thus, the shaft body 4 can be moved horizontally and vertically. The pressing force of the electrode piece is obtained by an air cylinder mechanism, a spring mechanism, or the like. These electrode pieces 9 and 9 are plate pieces having a predetermined thickness, and a pinching portion having the same shape as the cross-sectional shape (half half portion) of the side surface portion 12 of the shaft body 4 is provided at a portion where the shaft body 4 is pinched. 16 is formed. Here, as shown in FIG. 2, the cross-sectional shape of the shaft body 4 is circular, and the shape of each holding portion 16 of the electrode pieces 9, 9 is a semicircular shape having the same radius as that of the shaft body 4.

  Thus, by holding the shaft body 4 between the electrode pieces 9, 9, the distance between the joint and the electrode can be reduced, and the influence of the electrical resistance of the shaft body itself can be reduced. Further, by making the shape of the clamping portion 16 of each electrode piece 9, 9 the same as the shape of the side surface portion 12 (one half portion) of the shaft body 4, when the shaft body 4 is clamped, The entirety can be brought into contact with the side surface portion of the shaft body 4, whereby a large contact area between the two can be ensured and electric resistance can be reduced. In addition, since the shaft body 4 is held between the electrode pieces 9 and 9 with a predetermined pressing force, both are brought into close contact with each other, the contact resistance can be reduced, and electrical conduction between the two can be performed satisfactorily.

  By reducing the electrical resistance of this contact portion, heat generation at this portion is reduced during energization, and adverse effects such as alteration (alloying reaction) and deterioration due to heat of the material and the electrode are prevented. The moving mechanism of the upper electrode 8 has a function of sandwiching the shaft body 4 and moving and positioning it to the position of the hole 3 to be joined to the plate 2, a function of setting / holding at the position above the hole 3, and a shaft A function of energizing the body 4 while holding it. In this way, by energizing the shaft with the electrode held, the shaft can be accurately and stably press-fitted into the hole of the plate.

  The upper electrode 8 is composed of movable electrode pieces 9 and 9 for transporting the shaft body 4. In order to ensure the positioning accuracy of the shaft body 4, the shaft body 4 is sandwiched by the upper electrode. Then, after moving to the upper position of the hole 3 of the plate 2, the position can be fixed at this position. In addition, positioning accuracy can be ensured by arranging one of the electrode pieces 9 and 9 at a fixed position and sandwiching the shaft body 4 so that the other can be pressed.

  Energization is performed between the lower electrode 6 and the upper electrode 8. At this time, since the pressing electrode 10 is used as a part of the upper electrode 8, the electrical resistance between the shaft body 4 and the upper electrode 8 is reduced, and a good current can be supplied. Since the shaft body 4 is made of a steel material having a larger electrical resistance than the electrodes, the influence of the electrical resistance of the shaft body 4 itself is reduced by using the three electrodes 6, 8, and 10, and heat generated by the electrical resistance is reduced to the plate 2. The electric loss is reduced by concentrating in a narrow range of the joint portion 11 between the shaft body 4 and the shaft body 4. Further, the electrode pieces 9, 9 of the upper electrode 8 can be smoothly moved downward as the pressing electrode 10 is lowered so as not to hinder press-fitting.

  The shape of the sandwiching portion 16 of the electrode pieces 9, 9 is the same as or slightly larger (large radius) than the shape of the half portion of the cross section of the joined body such as the shaft body 4. For example, when the cross-sectional shape of the joined product is circular, the shape of the sandwiching portion of the electrode piece is a semicircular shape with the same radius or a partial arc shape thereof, and the contact resistance is reduced by increasing the adhesion between them. To do. Therefore, for example, as shown in FIG. 3A, when the cross-sectional shape of the shaft body 4 is circular, the shape of the holding portion of the electrode piece 9 is an arc shape (or semicircular shape) having the same radius. To do.

  In addition, when the electrode pieces are two electrodes, due to manufacturing error of each member, etc., as shown in FIG. 3C, only both ends of the electrode pieces hit the shaft body and the contact between them is insufficient. Can be assumed. For this reason, as described above, the shape of the holding portion of the electrode piece is the same as the outer shape of the side surface portion of the shaft body, or the cross-sectional radius of the holding portion of the electrode piece is formed slightly larger (FIG. 3B). You may do it. Also, as shown in FIG. 3 (d), by providing a slit in the middle part of the electrode, the slit is widened by a holding force to open the holding part of the electrode piece, and thereby the holding part is used as a shaft body. It can be adhered.

  On the other hand, the electrode material is soft, such as chromium copper. For example, when the shaft body is made of steel, the shape of the electrode piece can be adapted to the shaft body. In addition, the contact area between the electrode and the shaft is set to be equal to or larger than the area of the joint 11 to be press-fitted and joined to lower the electrical resistance so that heat generated by the electrical resistance is concentrated at the joint. At the same time, the contact position (energization position) between each electrode piece and the shaft body is close to the joint 11 between the shaft body and the plate (however, the height range to be press-fitted is ensured) and is equidistant. Desirably, the interval between adjacent electrode pieces is made as small as possible, thereby reducing the influence of the electric resistance of the shaft itself, and increasing the contact area with the electrode to reduce the electric resistance.

  In the above embodiment, the structure in which the shaft body 4 is sandwiched by the upper electrode 8 can ensure a wide contact area between the two, and an electrode can be provided in the vicinity of the joint 11 so that the shaft The influence of the electrical resistance of the body 4 itself is reduced, and energization can be performed well. Further, by supporting the shaft body 4 with the shaft body 4 interposed therebetween, the shaft body 4 can be efficiently held, transported, and attached, so that work efficiency is improved and workability is greatly improved.

  FIG. 4 shows a mode in which the shaft body 4 is sandwiched using three electrode pieces 20. In this embodiment, the shape of the sandwiching portion 21 of the electrode piece 20 is the same as the shape of the side surface portion 12 of the shaft body 4 that is a joined product, but the degree of depression of the sandwiching portion 21 of each electrode piece 20 is shallow. The electrode piece 20 is easily detached from the shaft body 4. Thus, when there are three or more electrode pieces, there is no problem that the shaft body is sandwiched between the electrode pieces and is not easily removed as in the case of two electrode pieces.

  The upper electrode 8 is sandwiched from both sides of the shaft using two electrode pieces. As described above, the upper electrode 8 is composed of three electrode pieces, and further four or more electrode pieces. It can be in the form of having. Among these, the electrode composed of two electrode pieces has a relatively simple structure for holding the electrode pieces, and simplification of the apparatus can be expected. On the other hand, an electrode using three or four electrode pieces is There is an advantage that the support of the shaft body 4 is concentrated and stabilized at the center, and the shaft body can be easily attached and detached.

  FIG. 5 shows both forms (cross sections) in the case of holding various shaft bodies 24 (solid, hollow) using the electrode pieces 22. In addition, this form shows the form about both pinching site | parts, and it does not necessarily correspond with the shape of the junction part of a shaft or a cylinder. As for the shaft body and the like, there may be a case where the holding portion is circular in cross section and the cross section of the joining portion is oval or vice versa.

  FIG. 5A shows an elliptical shape in which the side surface portion of the shaft body 24 has an elliptical cross section, and FIG. 5B shows an elliptical shape in which the cross section is hollow. FIG. 5C shows a configuration in which the side surface portion of the shaft body 24 has a quadrangular cross section, and FIG. 5D shows a shape in which the side surface portion of the shaft body has an oval cross section. In this case, (a) and (b) are the same as the shape of the side surface (half part) of the shaft body, and the side surface of the shaft body is held when the electrode body is sandwiched. This is a form in which the sandwiching portion of each electrode piece comes into contact with the entire portion (half portion). Further, (c) and (d) show that the shape of the holding portion of the electrode piece is the same as the shape of a part or the whole of the side surface portion (half portion of the shaft body), and this shaft is held when held. About half or more than half of the side surface (half part) of the body is in contact with the sandwiching part of each electrode piece.

  In the rectangular shaft body 24 of FIG. 5C, the cross-sectional shape of each corner is a partial shape (arc) of a circle centering on the core of the shaft body. The shaft body 24 has an outer diameter (diameter) of the joint portion slightly larger than the diameter of the hole portion 3 of the plate 2, and due to this press-fitting allowance, the outer peripheral portion of the joint portion of the shaft body 24 becomes the hole portion of the plate 2. 3 is in contact with the inner wall surface of the plate 2 and press-fitted into the hole 3 of the plate 2, the corner of the shaft body is press-fitted into contact with the hole 3, so that partial joining is performed in which a part is press-fitted. Similarly, partial joining is performed on the oval shaft body 24 shown in FIG.

  FIG. 6 shows a configuration in which the contact portion between the shaft body and the electrode piece is relatively rough. In FIG. 6A, the shape of the sandwiching portion of the electrode piece 22 is V-shaped, and the electrode piece of this form is compatible with various shapes of the shaft body 24 and is versatile. FIG. 6B is a case where a plurality of protrusions are formed on the sandwiching portion of the electrode piece 22, and is applied when the shape of the side surface portion of the shaft body 24 is not constant, or when there are irregularities. This is used when some element parts have complicated shapes, and such parts are handled as shaft bodies.

  FIG. 7A shows a press-fit joining mechanism using another form of the upper electrode 30. The upper electrode 30 has a pair of electrode pieces 32 and 33, and the shaft body 4 is sandwiched between these electrode pieces. Each electrode piece 32, 33 is formed with a pressing portion 34 bent in an L shape. For this reason, the electrode pieces 32 and 33 have a function of pressing the shaft body 4 in the axial direction in addition to the function of holding the shaft body 4.

  As the upper electrode 30, for example, the form of the collet chuck 35 shown in FIG. 7B and the function as a fastening tool can be applied. This has three electrode pieces 36 made of chrome copper as upper electrodes, and the shaft body 4 is held by these electrode pieces 36 using the function of a chuck. According to the electrode of the collet chuck, the shaft body can be easily held and moved, and the positioning accuracy can be improved. Further, as the upper electrode, in addition to the side surface portion of the shaft body, the upper surface portion contacts to further reduce the electric resistance, and the shaft body can be pressed to reduce the number of parts.

  FIG. 8 shows a press-fit joining mechanism for positioning using a fastening tool such as the collet chuck 35. This has electrode pieces 38 and 39 as upper electrodes, and the shaft body 4 is pinched by these electrode pieces, while the upper portion of the shaft body 4 is held by the collet chuck 35. The shaft body 4 is moved and positioned by the collet chuck 35, and the collet chuck 35 is pressed by a press mechanism.

  According to the collet chuck 35, the shaft body 4 can be easily held and moved, and the positioning accuracy can be improved. At this time, the collet chuck 35 can function as a part of the upper electrode, whereby the electrode is in contact with the upper and upper surface portions in addition to the side surface portion of the shaft body, and the electrical resistance is further reduced. This press-fit joining mechanism is stable and effective especially when the shaft body 4 is relatively long.

  FIG. 9 (a) shows a press-fit joining mechanism using still another form of the upper electrode 40. FIG. The upper electrode 40 divides the electrode into two electrode pieces 42 and 43, and the shaft body 4 is held between the divided electrode pieces 42 and 43.

  As shown in FIG. 9B, the electrode piece 42 has a rectangular parallelepiped shape, and a holding portion 44 is formed on the side holding the shaft body. The electrode piece 43 is formed with a groove 45 cut at a constant width, a holding portion 44 for holding the shaft body 4 is provided on the lower side of the electrode piece 43, and the shaft body 4 is provided on the upper side. A pressing portion 46 that covers the upper portion is provided. For this reason, the electrode piece 43 has a function of holding the shaft body 4 and pressing the shaft body 4 in the axial direction. The electrode piece 42 can be fitted into the groove 45 of the electrode piece 43, and the shape of the holding portion 44 of each electrode piece 42, 43 is the same as the shape of the side surface portion (one half portion) of the shaft body. Is formed. Also in this upper electrode, in addition to the side surface portion of the shaft body, the upper surface portion contacts to further reduce the electrical resistance, and the shaft body can be pressed to reduce the number of parts.

  FIG. 10 shows a press-fit joining mechanism provided with an upper electrode 70 for supporting the shaft body 4 particularly when the shaft body 4 is long. The upper electrode 70 has a substantially frame shape formed entirely of chrome copper. The upper electrode electrode 71, the left and right support electrode portions 72 and 73, and the lower portions of the support electrode portions 72 and 73, respectively. It has left and right electrode pieces 74 and 75 formed facing each other. The shape of the sandwiching portion 76 of these electrode pieces 74 and 75 is also formed partly or entirely the same as the shape of the side surface portion (half portion) of the shaft body 4, similarly to the electrode pieces 9 and 22. . The support electrode portions 72 and 73 are formed to have a length corresponding to the length of the shaft body 4 in order to ensure a space between the pressing electrode portion and each electrode piece. By providing the support electrode portions 72 and 73 on both sides in this way, current can be supplied in a well-balanced manner, and the shaft body can be stably supported.

  The upper electrode 70 has a configuration in which the shaft body 4 is supported at the central portion, and the vicinity of the lower portion of the shaft body 4 is held between the electrode pieces 74 and 75, while the upper portion of the shaft body 4 is a pressing electrode portion. 71 is held with an insulator 77 interposed therebetween. The electrode pieces 74 and 75 hold the shaft body 4 by using, for example, air cylinder pressure or spring pressure. A plate-like pressing electrode 78 is disposed above the pressing electrode portion 71, and the pressing electrode 78 is pressed by a pressing mechanism.

  The insulator 77 insulates the upper portion of the shaft body 4 so that no current flows through the shaft body 4 itself. Even in the in-house test, it was confirmed that if current is passed through the shaft body 4 from above without providing the insulator 77, the amount of heat generated at the joint between the shaft body 4 and the plate 2 is reduced, and the joining cannot be performed sufficiently. ing. In particular, when the shaft body 4 is long and the material of the shaft body 4 is stainless steel or the like having a high electrical resistance, the shaft body 4 itself generates heat when the current flows through the shaft body 4, and heat is generated at the joint. The amount is undesirably reduced. This is presumed to be caused by inconvenience in the supply to the junction because the current flow and the difference in electrical resistance between the shaft body 4 and the electrode affect the current flow and the current flow is restricted. The According to in-house implementation, the shaft body 4 is made of steel and the diameter is 10 mm, the total length is about 40 mm to 130 mm, and the shaft body 4 is made of stainless steel, the diameter is about 10 mm, and the total length is about 30 mm or more. In this case, the effect of the insulator 77 is observed, and the press-fitting is favorably performed by the interposition of the insulator.

  In this upper electrode 70, the pressing electrode 78 on the upper side of the pressing electrode portion 71 is pressed by the pressing mechanism, while the current applied to the pressing electrode 78 from the power source is supported by the supporting electrode portions 72 and 73 via the pressing electrode portion 71. The current passes through the support electrode portions 72 and 73 to reach the electrode pieces 74 and 75 and is supplied to the shaft body 4. According to this upper electrode, even a long shaft body can be supported accurately and stably, and it is practical, and a current can be supplied from the vicinity of the joint portion of the shaft body so that the shaft body can be supplied. In addition, the contact resistance between the electrode and the shaft body is reduced, and the shaft body can be pressed efficiently.

  FIG. 11 shows a press-fit joining mechanism suitable for positioning the plate 2 disposed on the lower electrode 6. In this configuration, a spring 82 is disposed in a hole 80 provided in the lower electrode 6, and a positioning member 84 is disposed above the spring 82. The positioning member 84 is made of an insulating material such as a synthetic resin or ceramics, and an engaging portion 87 protruding in a cylindrical shape from the base portion 86 is formed, and a step portion 88 is provided therebetween. Further, the upper portion of the hole 80 is formed with a locking hole 81 having a reduced inner diameter. The outer diameter of the engaging portion 87 is slightly smaller than the hole portion 3 of the plate 2, and the inner diameter of the locking hole portion 81 is slightly larger than the diameter of the shaft body 4.

  Here, in the positioning member 84, the engaging portion 87 protrudes from the surface portion 7 of the lower electrode 6 in a state where the step portion 88 is locked to the locking hole portion 81 of the hole portion 80 of the lower electrode 6. . In this state, by positioning the hole 3 of the plate 2 so as to fit into the engaging portion 87, the plate 2 can be positioned accurately. When the shaft body 4 is press-fitted, the positioning member 84 moves downward against the spring 82 as the shaft body 4 is lowered, and returns when the joined product is removed. The positioning member provided in the hole 80 allows the positioning of the plate 2 to be performed easily and accurately. In addition, the locking hole 81 has effects such as escape of the plate and prevention of sparks as with the hole 15. It is done.

  Materials for workpieces such as plates and shafts include steel materials for general processing, high-tensile steel materials for automobiles, other metal materials, SUS (stainless steel), a combination of SUS and carbon steel, carbon steel for machine structures Alloy steel for machine structure, heat-resistant steel, tool steel, spring steel, cast iron, free-cutting steel, bearing steel, steel for general processing, steel for pressure vessels, light metals such as titanium, aluminum, magnesium, light metal alloys, etc. are applicable It is.

  The press-fitting and bonding apparatus is equipped with a press mechanism (not shown). The press mechanism is configured to be able to press the pressing electrode 10 arranged on the upper portion of the shaft body 4 and pressurizes and lowers the shaft body 4. On the other hand, a robot as a transfer device is arranged together with the press mechanism, and this robot can hold the plate 2 and the shaft body 4 with an arm (manipulator or the like), and transports the plate 2 and the shaft body 4 to a predetermined position. be able to.

Here, a process when the shaft body 4 is press-fitted and joined to the plate 2 as a workpiece as shown in FIG. 1 using the press-fitting device will be described.
(1) Using a robot, the plate 2 is transported to the surface portion 7 of the lower electrode 6 and placed at a predetermined position. For example, the plate 2 may be held and fixed at the predetermined position by pressing a pinching member from both sides.
(2) The shaft body 4 is transported to the upper part of the hole 3 of the plate 2 using a robot and temporarily placed at this position.
(3) The shaft body 4 is held by the electrode pieces 9 and 9 of the upper electrode 8 with a predetermined pressing force, and the position of the shaft body is adjusted and positioned at the same center of the hole 3 of the plate 2. Ensure sufficient positional accuracy.
(4) The upper part of the shaft body 4 is pressed through the pressing electrode 10 by the press mechanism, and a constant pressure is applied to the shaft body 4.
(5) Energization is performed between the upper electrode 8 (and the pressing electrode 10) and the lower electrode 6. Then, a current flows through a joint portion between the shaft body 4 and the hole 3 of the plate 2, and heat is generated by electric resistance heat due to contact resistance, and the joint portion is softened.
(6) Due to the softening of the joint, the pressure-biased shaft body 4 is press-fitted into the hole 3 of the plate 2. At this time, due to the press-fitting allowance, a squeezing action is produced at the joint between the two members, and a clean joint interface is formed and press-fit joining is performed. The press-fit joining here is solid-phase joining accompanied by plastic deformation (thermoplasticity) by press-fit. The shaft body 4 is press-fitted into the hole 3 of the plate 2 to a required depth.

  In the press-fitting method, the workpiece is transported by a robot, and then the shaft is separately clamped by the upper electrode and press-fitted to the plate. In this method, the structure of the upper electrode can be simplified, and the upper electrode can be directly attached to the lower electrode or the like as the main body of the bonding apparatus so that it can be mounted accurately and firmly. Therefore, the positioning accuracy or repeatability is good. In this method, the robot acquires the next workpiece during press-fit welding, transports it to a predetermined position, and moves the workpiece after joining to the next process. .

  As another press-fitting method, the robot can be equipped with electrodes, and the robot can transport the shaft body to the joining position while holding the shaft body, and can position and hold the shaft body at this position and press-fit to the plate as it is. . In this method, for example, in a form in which a plurality of shaft bodies are joined to the same plate, a flexible response is possible. In addition, the structure of the joining apparatus itself can be simplified, which is suitable when there are many types of workpieces.

  In the above press-fitting process, a sliding direction motion is generated at the bonding interface, which removes and removes the surface impurity layer, oxide film, etc., and this action forms a clean bonding surface essential for solid phase bonding. As a result, the two are firmly joined. Then, after energization is completed, the pressure applied by the press mechanism is unloaded and the pressing electrode 10 is pulled up. At the same time, the electrode pieces 9, 9 are pulled away from the shaft body 4 sandwiched by the upper electrode 8, the shaft body 4 is opened and detached, and the press-fitting process is completed.

  FIG. 12 shows a mechanism for press-fitting and joining a shaft body and a cylindrical body as another embodiment. This shows a form in which a cylindrical body 52 and a shaft body 54 are used as a workpiece using a press-fit joining apparatus, and the shaft body 54 is press-fitted and joined into a hole 53 of the cylindrical body 52. The shaft body 54 may be rod-shaped (solid) or cylindrical (hollow).

  This press-fit joining apparatus also has a press-fit mechanism having an electrode for energization, a moving mechanism for positioning movement, and a press mechanism. The press-fitting mechanism includes a support plate 56 that supports the cylindrical body 52, a lower electrode 58 that is divided into two electrode pieces 59 and 59 that sandwich the cylindrical body 52, and two that sandwich the shaft body 54. The upper electrode 64 is divided into electrode pieces 62 and 63, and each electrode is made of chrome copper. The support plate 56 is made of chrome copper and also functions as a part of the lower electrode 58.

  The electrode piece 62 of the upper electrode 64 is formed with a holding portion 66 for holding the shaft body 54, and the electrode piece 63 is narrow to hold the shaft body 54 on the lower side like the electrode piece 62. A holding portion 66 is formed, and a pressing portion 67 that is bent in an L shape from the holding portion 66 and covers the upper portion of the shaft body 54 is provided on the upper side. For this reason, the electrode piece 63 has a function of pressing the shaft body 54 in addition to a function of holding the shaft body 54.

  The lower electrode 58 has two electrode pieces 59 and 59 as the upper electrode 64 as an electrode for sandwiching the cylindrical body 52. These electrode pieces 59, 59 are plate pieces having a predetermined thickness, and a holding portion having the same shape as the cross-sectional shape of the side surface portion of the cylinder body 52 is formed in a portion where the cylinder body 52 is held. . The upper electrode 64 is held by a moving mechanism, and the moving mechanism mechanically holds the side surface portion of the shaft body 54 with two electrode pieces 62 and 63 together with a predetermined pressing force. The shaft body 54 is transported to the upper portion of the hole 53 of the cylindrical body 52 by the moving mechanism while being held by the upper electrode 64, and is positioned, held, and fixed.

  When the shaft body 54 is press-fitted and joined, the pressing mechanism presses the shaft body 54 via the electrode piece 63, and the upper electrode 64 can be lowered by the vertical movement function of the moving mechanism. The press-fitting process is the same as the above process. When a current is passed between the upper electrode and the lower electrode, the joined part generates heat due to electric resistance heat, and the pressure-biased shaft body is press-fitted into the cylinder.

  In this way, by sandwiching the shaft and cylinder as a workpiece with two electrode pieces (3 or more are also possible), the influence of the electrical resistance of the contact portion between them and the workpiece itself can be reduced. By making the shape of the holding portion of the piece the same as the shape of the side surface portion of the workpiece, it is possible to secure a wide contact area between them and reduce the electric resistance.

  Next, as an embodiment, the case where the shaft body, the plate, the cylinder body, and the shaft body as a workpiece are plated as a surface treatment will be described. In general, when assembling a member, it is preferable to first perform plating on each part and perform processes such as assembly and joining using these parts in order to save labor. For this reason, the said press-fit joining at the time of using the workpiece | work with which the surface was plated is demonstrated.

  The types of plating and the plated materials include hot dip galvanized steel sheet, alloyed hot dip galvanized steel sheet, electrogalvanized steel sheet, alloy galvanized steel sheet, and other galvanized steel sheets. It is not easily rusted even when overheated, and the paint is well adapted to it. Other surface treatments such as plating include nickel plating, nickel composite plating, copper plating, tin plating, chromate treatment, and phosphoric acid treatment.

  Here, in the press-fit joining according to the above-described embodiment, since the joining portion, which is a heat generation place, is different from the attachment location of the electrode, the area of the contact portion between the electrode and the workpiece such as the shaft body, plate, etc. Can be set large, heat generation at the contact portion between the electrode and the workpiece is small, and the temperature from the solid phase bonding to the bonding portion is lower than that of general projection welding. For this reason, the plating material in contact with the electrode does not cause an alloy chemical reaction due to high heat, the electrode is prevented from being deteriorated and crushed, and the durability of the electrode is excellent. Almost no. On the other hand, in general projection welding, electrodes are arranged on both surface portions of the joint portion between the overlapped plate materials, and the joint portion near the electrode melts due to resistance heat generation. Thus, the surface portion of the plate material is exposed to a high temperature, causing an alloy chemical reaction between the electrode and the plating material, and the durability of the electrode is lowered.

  Further, in the above press-fit joining, when using a bare material that is not plated on a steel material such as a plate and a shaft body, and a case using a surface-treated material plated with alloying hot dip galvanizing or the like, There is no difference between the current amount or the bonding strength. This is because, with respect to general projection welding in which the respective surface portions of the members to be joined are joined together, in the above press-fit joining, there is no element that is affected by the electric resistance due to the plating process because of the structure in which the members are press-fit into the holes. Because.

  Thus, in general projection welding (spot welding), the surface portions of members are brought into contact with each other, and this portion is heated and melted to be easily welded. On the other hand, the press-fit joint structure is joined by press-fitting. Since the surface of the part is squeezed and joined in a state in which the impurity layer on the surface is scraped off, even if the inside of the hole of the shaft body and the plate is plated, the plating is scraped off during the press fitting The influence on the press-fit joint by plating can be ignored.

  In projection welding, spatter is likely to occur due to a molten metal such as nugget or plating, but the press-fit joining does not melt the member because of solid phase joining, and therefore spatter is very likely to occur. Sputtering does not occur even when plating is applied. Furthermore, spot welding on galvanized steel sheets requires a larger current than that of bare materials, but the solid-phase joining does not differ greatly regardless of whether it is bare or plated, and process management is easy. is there.

  The press-fit joining method can be used for the production of automobile component parts, for example, the production of parts such as transmission control lever components, shift lever components, etc., in which a cylinder is joined to a plate part, or engine parts. Is preferred.

  Therefore, according to the press-fit joining according to the above-described embodiment, the shaft body is held and energized with a predetermined pressing force by two or a plurality of electrode pieces, so that the electrical resistance of the contact portion between the electrode and the shaft body is reduced. In addition, since the electrode is provided on the side surface portion of the shaft body, the influence of the resistance of the shaft body itself is reduced, current can be satisfactorily performed, and electrical resistance heat suitable for the joint portion is ensured. Also, in this press-fitting, since the shaft body can be accurately positioned and held stably during press-fitting, the joining accuracy is excellent, and solid-phase joining does not cause thermal deterioration of the joint, resulting in good finishing accuracy. Thus, there is an effect that a good working environment can be obtained without generation of spatter.

  Furthermore, since the bonding interface is cleaned and the bonding is performed well, the strength is excellent, and in addition, since the solid-phase bonding is used, the heat influence range on the member (base material) is small, so the high accuracy Bonding is ensured, finishing accuracy is good, and post-processing is almost unnecessary. It is a simple process with only press-fitting and energization, and it can be joined quickly and manufactured easily, with a low manufacturing cost and excellent economy.

It is a figure which shows the press fit joining which concerns on embodiment of this invention. It is a figure which shows the relationship between the shaft body which concerns on embodiment, and the clamping part of an electrode piece. It is a figure which shows the shape (a) (b) (c) (d) of the various clamping parts of an electrode piece. It is a figure which shows the form which has three electrode pieces as an electrode. It relates to the form of the shaft body and the electrode piece. (A) shows the shape of the elliptical shape of the side surface of the shaft body, (b) shows the shape of the elliptical shape of the cross section of the shaft, and (c) shows the side surface of the shaft body. (D) is a figure which shows the side surface part of a shaft body in the shape of a cross-sectional oval shape. In relation to the shape of the shaft body and the electrode piece, (a) shows a shape in which the holding part of the electrode piece is V-shaped, and (b) shows a form in which a plurality of protrusions are provided on the holding part of the electrode piece. FIG. (A) is a figure which shows the press-fit joining which has an electrode of another form, and (b) is a figure which shows the electrode which has three electrode pieces concerning embodiment. It is a figure which shows the mechanism of the press injection joining which concerns on embodiment and positions using a clamp. It is a figure which shows the mechanism of the press-fit joining which concerns on embodiment and has an electrode of another form. It is a figure which concerns on embodiment and shows the form of the press-fit joining which has an electrode suitable for press-fit of a long shaft body. It is a figure which shows the form of the press injection joining which concerns on embodiment and has an electrode suitable for positioning of a plate. It is a figure which shows the press-fit joining which concerns on other embodiment of this invention. It is a figure which shows the press-fit joining which concerns on a prior art example.

Explanation of symbols

2,52 First member (plate, cylinder)
3,53 hole 4,54 second member (shaft)
6,58 First electrode (lower electrode)
8,64 Second electrode (upper electrode)
9, 59, 62, 63 Electrode piece 10 Third electrode (pressing electrode)
15 hole 46 pressing part 71 pressing electrode part 72, 73 supporting electrode part 84 positioning member

Claims (13)

A first member having a hole in which an inner wall surface portion having the same cross-section of the press-fit portion is formed;
A predetermined press-fitting allowance is provided between the hole and the shaft-shaped second member in which a joint surface portion directed in the axial direction is formed.
While the first member is disposed on the surface portion of the first electrode, the side surface portion of the second member is mechanically sandwiched by the second electrode composed of a plurality of electrode pieces,
While pressing the sandwiched second member toward the inside of the hole of the first member with a predetermined pressure, energizing between the two members to generate electrical resistance heat at the joint, The second member is press-fitted into the hole, a bonding interface is formed at the bonding portion between the bonding surface of the second member and the inner wall surface of the hole, and the bonding is a solid-phase bonding. A press-fit joining method characterized by   2. The press-fitting method according to claim 1, wherein a hole having a diameter larger than that of the hole is provided on the surface of the first electrode so as to communicate with the hole of the first member.   An insulating positioning member capable of moving up and down is disposed in the hole of the first electrode, and the positioning member is positioned by engaging the hole of the first member with the positioning member. 2. The press-fit joining method according to 2. A cylindrical first member having a hole in which an inner wall surface portion having the same cross-section of the press-fit portion is formed;
A predetermined press-fitting allowance is provided between the hole and the shaft-shaped second member in which a joint surface portion directed in the axial direction is formed.
The side surface portion of the first member is mechanically clamped by a first electrode made of a plurality of electrode pieces, while the side surface portion of the second member is mechanically held by a second electrode made of a plurality of electrode pieces. Pinching,
While pressing the sandwiched second member toward the inside of the hole of the first member with a predetermined pressure, energizing between the two members to generate electrical resistance heat at the joint, The second member is press-fitted into the hole, a bonding interface is formed at the bonding portion between the bonding surface of the second member and the inner wall surface of the hole, and the bonding is a solid-phase bonding. A press-fit joining method characterized by   The shape of the sandwiching portion of the electrode piece in the second electrode is formed to be the same as the shape of the side surface portion of the second member, and when sandwiched, the electrode piece is placed on the side surface portion of the second member. The press-fit joining method according to any one of claims 1 to 4, wherein the whole or a part of the holding portion is in contact.   6. The device according to claim 1, wherein the second electrode can be moved in a state where the second member is held, and the second member can be positioned and held at a predetermined position. The press-fit joining method according to the above.   The press-fitting method according to any one of claims 1 to 6, wherein a pressing portion capable of pressing an end surface portion of the second member in an axial direction is provided on the electrode piece of the second electrode.   The number of electrode pieces of the second electrode is two or three, and a third electrode that is a part of the second electrode is provided on the axial end surface of the second member. The press-fit joining method according to any one of claims 1 to 6.   A supporting electrode portion for providing a pressing electrode portion above the electrode piece of the second electrode, maintaining a predetermined interval between the pressing electrode portion and each electrode piece, and supplying a current to the electrode piece The upper part of said 2nd member is hold | maintained so that it can press with the said press electrode part, On the other hand, the lower part vicinity of this 2nd member is clamped by the said electrode piece. The press-fit joining method according to any one of the above.   The press-fit joining method according to claim 9, wherein the press electrode part and the upper part of the second member are electrically cut off.   The press-fit joining method according to any one of claims 1 to 10, wherein the surface of the first member or the second member is plated.   12. The press-fit joining method according to claim 11, wherein the plating is performed by hot dip galvanization, alloyed hot dip galvanization, electrogalvanization or alloy galvanization.   A press-fit joining component manufactured by the press-fit joining method according to any one of claims 1 to 12, wherein the second member is joined to a hole of the first member.

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