[0001]
　The present disclosure relates to mechanical bonding apparatus, in particular, the tensile strength is related to the mechanical bonding apparatus for bonding a plurality of metal plates including more than one of the above high strength steel sheet 780 MPa.
Background technique
[0002]
　In recent years, in the automotive field, lower fuel consumption and CO 2 in order to reduce emissions, while the vehicle body weight, for the improvement of collision safety, are required to the vehicle body member with high strength. To satisfy these requirements, it is effective to use a high strength steel sheet such as a vehicle body or parts. Therefore, there is an increasing demand for high-strength steel sheet. To use the high-strength steel sheet, such as a vehicle body or parts, it is necessary to join the high-strength steel plate and other metal plates, in this bonding, has the following problems.
[0003]
　Conventionally, such attachment of the body assembly and parts, mainly, have been carried out by spot welding, also joining of a plurality of metal plates including a high-strength steel sheet is performed by spot welding. Such, by superimposing a plurality of metal plates, in the joint formed by spot welding, the tensile strength is an important property. The tensile strength, the tensile shear strength is measured by a load tensile shear direction (TSS), there is a cross tensile strength (CTS) to be measured by a load tensile peeling direction.
[0004]
　270 CTS spot welded joint formed by a plurality of steel plates having a tensile strength of ~ 600 MPa increases with increasing strength of the steel sheet. Accordingly, the spot welding joint is formed by a steel sheet having a tensile strength of 270 ~ 600 MPa, problems with joint strength is unlikely to occur.
[0005]
　However, in the spot welded joint formed by a plurality of metal plates including more than one sheet of steel plate having a tensile strength of at least 780 MPa, even if increase the tensile strength of the steel sheet, CTS is either not increase or decrease. This is possible due to the high content of it and alloying elements increases the stress concentration to the weld portion due to a decrease in deformability, by and solidification segregation is baked into the weld toughness of the weld is reduced There is a reason.
[0006]
　Therefore, at the junction of a plurality of metal plates including a steel sheet having a tensile strength of at least 780MPa or one, a technique for improving the CTS is needed. As one of techniques for solving it, there is a technique of mechanically joined without melting the base metal. Specifically, overlay a plurality of metal plates are a material to be joined, while holding the outer circumference of the punch plate presser for preventing jumping of the metal plate, driving the rivet punch, a plurality of metal plates are there is a technique of mechanically joined.
[0007]
　However, in this technique, for driving the rivet, deforming the die side of the metal plate becomes very large, the ductility missing or deformed localized problem cracking occurs at the die side of the metal plate, the shearing direction and the peeling direction If the tensile stress is applied, rivets fracture occurs missing, shearing direction and the peeling direction of the tensile strength for the problem that a sufficient value can not be obtained, as well as joint and soft steel plate of high-strength steel sheet of the same riveting system for fittings, when comparing the fatigue strength of both, there is a problem that almost no difference.
[0008]
　As a technique for solving such a problem, Patent Document 1, the high-strength steel sheet of the superimposed tensile strength 430 ~ 1000 MPa, passed through by implanting rivet by deforming the leading end of the rivet passed through the machine to be joined, joining techniques to obtain a high strength steel sheet excellent in tensile properties and fatigue properties are disclosed.
[0009]
　The technique disclosed in Patent Document 1 is effective as a technique for joining a plurality of steel plates, the tensile strength is considered for high-strength steel sheet of up to 619MPa. However, in Patent Document 1, the tensile strength with respect to a plurality of steel plates containing the above high strength steel sheet 780 MPa, the application of the technique has not been studied.
[0010]
　Further, Non-Patent Document 1, at the junction of the high-strength steel sheet and aluminum alloy sheet, when mechanically bonded by implanting rivets, to a plurality of metal plates tensile strength including high strength steel sheet of about 590MPa is can be bonded without defects, tensile strength in the plurality of metal plates including a high-strength steel sheet of 980 MPa, the rivet is described as not able to penetrate the high-strength steel sheet.
[0011]
　In this way, by implanting rivet metal plate mechanically joining technique, usually, not the hole processing prior to bonding the materials to be joined, it is necessary to punch the welded material in the rivet itself, high strength steel sheet, for example, mechanically bonded by implanting rivet into a plurality of metal plates including more than one sheet of steel plate having a tensile strength of at least 780MPa had been difficult.
[0012]
　In contrast, Patent Document 2, or high work hardening has been bonded sheet having a high strength, a method for joining using rivets, start or just before the joining process, pressing member and the die, or pressing members and component disposed near the die, or by component disposed before a mechanical joining method local and heating temporally limit of the bonding sheet, carried out by electrical resistance heating There has been disclosed.
CITATION
Patent Literature
[0013]
Patent Document 1: JP 2000-202563 Patent Publication
Patent Document 2: JP-T 2004-516140 Patent Publication
Patent Document 3: JP 2007-254775 JP
Non-Patent Document
[0014]
Non-Patent Document 1: Ferrum, Vol. 16 (2011) No. 9, p. 32-38
Summary of the Invention
Problems that the Invention is to Solve
[0015]
　In Patent Document 2, there is a technique that can be applied to or higher work hardening steel sheet having a high strength. However, using the technique disclosed in Patent Document 2, the tensile strength by joining a plurality of metal plates including more than one of the above high strength steel sheet 780MPa by rivets, to implement the joint strength test of the resulting bonded joint , there is the peripheral that includes a rivet may be damaged.
[0016]
　The present disclosure, in view of the current state of the prior art described above, a plurality of metal plates including a tensile strength greater high-strength steel sheet more one even when riveting, damage to the peripheral including a rivet bonded joint obtained and to provide a mechanical joint system can be reduced.
Means for Solving the Problems
[0017]
　Accordingly, the present inventors have intensively studied how to solve the above problems. Steel sheet having a tensile strength of at least 780 MPa (hereinafter, "high-strength steel sheet" also referred to) a plurality of metal plates superimposed containing more than one (hereinafter, also referred to as "plate pair") and, in general-purpose products not high strength When joining the rivet, stress is concentrated in the low strength rivets was found that damage to the peripheral results including rivets.
[0018]
　Accordingly, the present inventors have studied means to increase the strength of the rivet. As a result, constitute the punch and die driving a rivet from the electrode material, were electrically heated by applying a current to the rivet after typing in a plate pair, by heat treatment of the rivet, the strength of the rivet is increased, damage to the peripheral, including the rivet was found to be reduced.
[0019]
　Mechanical bonding apparatus and mechanical bonding method of the present disclosure has been made based on the above findings, it is an gist is as follows.
(1) a mechanical bonding apparatus driving a rivet by punching a plurality of metal plates,
　a punch and die,
　and Itaosae,
　a first power supply,
　a second power supply,
　a cooling device,
　the provided,
　the punch and die, so that can be sandwiched between a plurality of metal plates superimposed, is arranged opposite,
　said plates holding is an insertable tubular body the punch inside , one end portion of said plate presser, the plurality of in contact with the punch side of the metal plate of the metal plate, is composed of the plurality of metal plates can pressed and energized heatable electrode material,
　the punch is configured implantation can and energization heatable electrode material rivet,
　said die, a supportable and said rivet the plurality of metal plates is composed of a current heatable electrode material,
　wherein the 1 power supply, the punch Before further implanting the rivet, so as to raise the temperature of said plurality of metal plates, is adapted to energize the plate retainer and said die,
　said second power supply, implanting the rivet by the punch as heat treatment by energizing the rivet after it is configured to energize said punch and said die,
　said cooling device is connected to the punch, so as to cool the rivet after the heat treatment of the rivet It is configured,
　the mechanical bonding apparatus.
(2) the cooling device further until completion driving from the start driving of the rivet, and is configured to cool the rivet, mechanical bonding apparatus according to (1).
(3) of said die, and said rivet portion opposite to the material is tool steel sandwiched between at least the plurality of metal plates, the material of the outer peripheral portion of the tool steel is copper or a copper alloy, mechanical bonding apparatus according to (1) or (2).
(4) A mechanical bonding method of implanting rivet by the punch on a plurality of metal plates,
　providing a plurality of metal plates,
　between the punch disposed opposite and die, said plurality of metal placing superposed plate,
　one end portion of the plate pressing is insertable tubular body the punch inside, is pressed against the punch side of the metal plate of the plurality of metal plates,
　the plates said plurality of metal plates pressed by the pressing, implanting rivet by the punch,
　before implantation of the rivet, so as to raise the temperature of said plurality of metal plates, through the plate retainer and the die the performing the electrical heating to the plurality of metal plates, and
　after typing the rivet by the punch, and electrically heating the rivet through the punch and the die, then the Liberation Cooling the bets,
　including, mechanical joining method.
(5) until completion of driving from the start driving of the rivet, further comprising a mechanical joining method according to (4) cooling the said rivet through said punch.
(6) of the die, a sandwich is made is a tool steel of the rivet facing the portion between at least the plurality of metal plates, the material of the outer peripheral portion of the tool steel is copper or a copper alloy, mechanical bonding method according to (4) or (5).
Effect of the invention
[0020]
　According to the mechanical joining system and mechanical bonding method of the present disclosure, reduced after typing a rivet on a plurality of metal plates, since the rivet is high strength heat treated, damage to the peripheral including a rivet bonded joint can do.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021]
[1] Figure 1 is a schematic sectional view showing the form of a mechanical joint. 1 (a) is a cross-sectional schematic view showing a state of performing a plate set of electrical heating before driving of the rivet, FIG. 1 (b), a state of electrically heating the rivet after implantation of the rivet schematic cross-sectional views showing.
FIG. 2 is a schematic sectional view showing the form of mechanical bonding in the case of using a tool steel to a portion of the die. 2 (a) is, in the case of using a tool steel to a portion of the die, a cross-sectional schematic view showing a state of electrically heating the plate pair before driving of the rivet, FIG. 2 (b), die when using a tool steel to a part of a cross-sectional schematic view showing a state of electrically heating the rivet after implantation of the rivet.
DESCRIPTION OF THE INVENTION
[0022]
　The present inventors have found that in the joint strength test of the resulting bonded joint was riveted, it was examined for damage caused to the peripheral including a rivet. As a result, damage to the peripheral including a rivet was found out occurs that when joining the plate set including a high-strength steel sheet, a general-purpose products of rivets not high strength. This stress on the rivet is concentrated low strength, bonding joint obtained by riveted was believed to be damaged.
[0023]
　Accordingly, the present inventors have studied means to increase the strength of the rivet. As a method to increase the strength of the rivet is to adjust the component composition, heat treatment of the applied technologies such as quenching is known (Patent Document 3). However, in this technique, the component composition of the rivet is limited, requires heat treatment furnace for heat treatment, resulting in increase in cost. Furthermore, a heat treatment step of the heat treatment furnace is required, there is a problem of causing an increase in the rivet of production time.
[0024]
　Therefore, without using a heat treatment furnace, it was examined means for implementing the heat treatment of the rivet mechanical bonding apparatus, constitute the punch and die driving a rivet in the electrode material, current rivets after typing in a plate assembly the energized heating flowing, was inspired heat treating the rivet. In other words, by heating the rivet steel made of general-purpose products to a temperature at which the austenite region, and the martensite structure was cooled and conceived that increasing the strength of the rivet.
[0025]
　The present disclosure provides a mechanical bonding apparatus driving a rivet by punching a plurality of metal plates,
　a punch and die,
　and Itaosae,
　a first power supply,
　a second power supply,
　a cooling device,
　the provided,
　the punch and die, so that can be sandwiched between a plurality of metal plates superimposed, is arranged opposite,
　said plates holding is a insertable tubular body the punch inside There, one end portion of said plate presser, the plurality of in contact with the punch side of the metal plate of the metal plate, is composed of a plurality of metal plates capable and energizable heating pressed electrode material ,
　the punch is configured implantation can and energization heatable electrode material rivet,
　said die, a supportable and said rivet the plurality of metal plates is composed of a current heatable electrode material,
　wherein the first power supply, said path Before implanting the rivet by Ji, to raise the temperature of said plurality of metal plates, is adapted to energize the plate retainer and said die,
　said second power supply, the rivet by the punch implanted it to heat treatment by energizing the rivet after, is adapted to energize said punch and said die,
　said cooling device is connected to the punch, to cool the rivet after the heat treatment of the rivet It is configured so as,
　to target mechanical bonding apparatus.
[0026]
　Hereinafter, with reference to the drawings, mechanical bonding apparatus of the present disclosure (hereinafter, also referred to as "joining apparatus") will be described. For convenience of explanation, the upper punch side, the die-side as the lower punch side of the metal plate upper metal plate, but refers to the die side of the metal plate and lower metal plate, joining device as long as it can be fixed, vertical, direction, such as horizontal placement does not matter.
[0027]
　(Embodiment 1)
　FIG. 1 shows a schematic sectional view showing the form of mechanical junctions with mechanical bonding apparatus of the present disclosure. 1 (a) is a cross-sectional schematic view showing a state of electrically heating the plate pair before driving of the rivet, FIG. 1 (b) represents a state of electrically heating the rivet after implantation of the rivet it is a schematic cross-sectional view.
[0028]
　As shown in FIG. 1 (a), in the mechanical connecting apparatus 1, so that it can sandwich the upper metal plate 2 and the lower metal plate 3 is a plate pair 4 superposed, facing the punch 5 and the die 6 is arranged. The outer periphery of the punch 5, Itaosae 7 is arranged.
[0029]
　Mechanical bonding apparatus 1, before implanting the rivet 8 by the punch 5, so as to raise the temperature of the plate assembly 4, the first power supply for energizing the Itaosae 7 and the die 6 (not shown) and the punch as rivet 8 which is driven by 5 is heat treated, a second power supply for energizing the punch 5 and the die 6 (not shown).
[0030]
　The before implanting rivets 8, the rivet 8, which are discharged by the punch 5 which means prior to contact with the punch side of the metal plate of the plate assembly 4.
[0031]
　By raising the temperature of the plate assembly 4 before implanting rivets 8, softened metal plate becomes easy driving of the rivet 8, in particular even when the plate group 4 contains the above high-strength steel sheet 780 MPa, cracking of the metal plate , rivets damaged, and it is possible to obtain a bonded joint without causing a rivet blind.
[0032]
　The first power supply is connected to Itaosae 7 and the die 6, and is configured to electrically heating the plate pair 4. The first power supply device comprises a first control device (not shown) for controlling the quantity of electricity (current value and the energization time) for energizing the Itaosae 7 and the die 6, heating the plate pair 4 to the desired temperature can do.
[0033]
　The first control unit energizes the Itaosae 7 and the die 6 so as to raise the temperature of the plate assembly 4 before driving of the rivet 8, further to the end driving of the rivet 8, heating the plate pair 4 to a predetermined temperature as controls to energize the Itaosae 7 and the die 6.
[0034]
　Electrical heating of the plate pair 4 is started before driving of the rivet 8, after completion of driving of the rivet 8 also continues, although thereafter may be stopped, preferably, stops driving of the rivet 8 ends substantially simultaneously .
[0035]
　Implantation and the end of the rivet 8, can be moved in the driving direction of the punch means the time when substantially stopped, it is detected by detecting the position of the punch. Method of detecting the position of the punch is not particularly limited, for example, it can be carried out using a device for detecting the position from the rotational speed of the ball screw to push the non-contact laser displacement meter or punch.
[0036]
　The heating temperature of the plate assembly 4 is improved plate set of ductility, cracking of metal plate such as a steel plate rivets breakage, and while suppressing the rivet blind, may be a temperature range which can drive a rivet. That is, the lower limit of the heating temperature of the plate assembly 4, cracking of the metal plate, rivets damaged, and may be set to a temperature capable of suppressing the rivet blind. The upper limit of the heating temperature of the plate assembly 4 may be a temperature below the melting point of the highest melting point is lower metal plate in the plate pair 4.
[0037]
　The lower limit of the heating temperature of the plate assembly 4 is preferably 400 ° C. or higher, more preferably 500 ° C. or higher, more preferably 600 ° C. or higher. The upper limit of the heating temperature of the plate assembly 4 is preferably 900 ° C. or less, more preferably 800 ° C. or less. May be lower than the temperature range at the start implantation, but is preferably heated is heated in the temperature range by the end implantation, more preferably, the plate assembly 4 at the start before or implantation the start implantation in the temperature range , the temperature of the plate assembly 4 until the end implant is maintained in the temperature range. Measuring point temperature of the plate assembly 4 is a riveting position of the surface of the upper metal plate in surrounded by Itaosae 7 region. The surface temperature of the upper metal plate, for example, can be measured using a thermocouple. Surface temperature measurement of the upper metal plate, before preparing a rivet, may be performed in advance. If advance for surface temperature measurement of the upper metal plate, when implanted by holding the rivet punch, it is possible to omit the temperature measurement.
[0038]
　Current for energizing the heating plate assembly 4, the plate assembly 4 to heat within the temperature range can be controlled by the first control device. The first control unit may control the current flowing through the plate assembly 4, for example 8 ~ 14 kA or 10 ~ 12 kA.
[0039]
　The second power supply is connected to the punch 5 and the die 6, after typing the rivet 8 by the punch 5, is configured to heat treatment by energizing the rivet 8 via a punch 5 and a die 6. The second power supply device includes a second control device for controlling the electric amount to be supplied to the punch 5 and the die 6 (the current value and the energization time) (not shown), heating the rivet 8 to the desired temperature can.
[0040]
　Mechanical bonding apparatus 1 includes a cooling device (not shown). Cooling device is connected to the punch 5, via the punch 5, it is configured to cool the rivet after the heat treatment of the rivet.
[0041]
　Using the second power supply and cooling unit, after the end driving of the rivet 8, a heat treatment of heating the rivet austenite region, then it can be cooled. Thus, the rivet 8 may have a martensite structure, it is possible to improve the strength of the rivet 8.
[0042]
　The heating temperature in the heat treatment of the rivet 8 is not particularly limited as long as it can heat the rivet 8 to the austenite region, preferably heated to a temperature below the melting point of A3 point-rivet. Current value and time in heating up to a maximum temperature of the rivet 8, for example, the current value can be 8 ~ 10 kA, time is 0.1 to 1.0 second.
[0043]
　Electrical heating of the rivet 8 may start from driving end of implant ends at the same time or rivets 8 rivets 8 after a predetermined time elapses. Second control apparatus, the driving end of the implant and end at the same time or rivets 8 rivets 8 after a predetermined time has elapsed, so as to energize the heating of the rivet 8, it is possible to control the second power supply.
[0044]
　Cooling device is not particularly limited as long as it can cool the rivet 8 through the punch 5, the punch 5 may have a cooling tube 9 therein. In FIG. 1 (a), are arranged inside the punch 5 is illustrated connected a cooling tube 9 to the cooling device.
[0045]
　Cooling tube 9, for example in the direction indicated by the arrow, is a tube which can be supplied to the refrigerant. The end portion of the punch 5 the rivet 8 is in contact with the other end on the opposite side, the cooling device may be provided which is connected to the cooling tube 9. The material of the cooling tube 9, by circulating a coolant therein is not particularly limited as long as it can cool the rivet through the punch 5 can be, for example, copper or a copper alloy. In this case, it is preferable that the punch 5 and high copper or copper alloy heat conductivity.
[0046]
　The refrigerant is not limited in particular, but may be a known refrigerant fluid or refrigerant gas, taking into account such economic and ease of handling, water is preferred.
[0047]
　Inside the cooling tube 9 without providing the punch 5, the cooling device so as to be in contact with the other end portion opposite arranged to the end portion of the punch 5 the rivet 8 is in contact, to cool the punch 5, the punch 5 by heat conduction, it may be cooled rivets 8. Again, it is preferable that the punch 5 and high copper or copper alloy heat conductivity.
[0048]
　Cooling device is provided with a control device, the control device may control the cooling temperature and cooling rate, as well as the timing of the cooling start and end.
[0049]
　Cooling conditions after heating the rivet 8 in the austenite region is not particularly limited as long as the martensite structure is obtained, a control device included in the cooling apparatus, after heating the rivet 8 in the austenite region, preferably in a cooling rate of more than 10 ° C. / sec, martensite transformation finish temperature of the rivet material below, typically to cool the rivet 8 to about 200 ° C. or less, it is possible to control the cooling device.
[0050]
　The first power supply and the second power supply device is not limited in particular, the power conventionally used, can be, for example, a DC power supply or AC power supply.
[0051]
　The first controller, second controller, and a control device provided in the cooling device is not limited in particular, can contain a known temperature controller.
[0052]
　The first controller may control the quantity of electricity using a temperature controller comprising a thermometer for measuring the temperature of the plate assembly 4, energizing the Itaosae 7 and the die 6. Depending on the combination of the metal plate of the plate assembly 4 obtained in advance the relationship between the current value and time to become a predetermined temperature, the first control device, the current value and time so as to first power supply it may be controlled.
[0053]
　The second controller may use a temperature controller comprising a thermometer for measuring the temperature of the rivet 8 to control the quantity of electricity for energizing the punch 5 and the die 6. Rivet 8 is obtained in advance the relationship between the current value and time to become a predetermined temperature, the second control apparatus may control the second power supply so that the current value and time.
[0054]
　Provided in the cooling system controller may use the temperature controller to control the cooling rate and cooling temperature of the rivet 8.
[0055]
　The first power supply and the second power supply may be separate power supply may be a function of may be a power device integrated, or the first power supply is a second power supply.
[0056]
　When the first power supply and the second power supply is integral power supply, or when the first power supply also has the function of the second power supply, the power supply is Itaosae 7 and the die 6 When, it is connected to both the punch 5 and the die 6.
[0057]
　Punch 5 may be a rod-like cross-sectional shape perpendicular to the longitudinal direction of the punch 5 is not limited in particular, circular, elliptical, it can be located in such as a rectangular shape. Punch 5 may have a different cross-sectional shapes in the longitudinal direction.
[0058]
　Punch 5, if the present invention is composed of the electrode material having a mechanical strength and electrical conductivity can be and conduction heating can drive a rivet 8, the material is not particularly limited, the desired material it is possible to select from. Punch 5 is preferably a Vickers hardness Hv is 300 to 510, configured electric conductivity from high copper or a copper alloy.
[0059]
　Die 6, if the present invention is composed of the electrode material having a mechanical strength and electrical conductivity and plate assembly can support a plurality of metal plates 4 and the rivet 8 may be electric heating, the material is not particularly limited, it may be selected from the desired material. Die 6 is preferably a copper or copper alloy.
[0060]
　The outer periphery of the punch 5, Itaosae 7 is arranged. Itaosae 7, the one end plate assembly 4 punch 5 side in contact with the metal plate plate sets 4 is a member which can be pressed against the die 6, along the longitudinal axis of the punch 5, the relative it can be moved. The shape of Itaosae 7 is a cylindrical body, such as a cylindrical punch 4 is inserted therein.
[0061]
　Itaosae 7, if the present invention is composed of the electrode material having a mechanical strength and electrical conductivity can be and conduction heating can be pressed against a plurality of metal plates to the die 6, the material is particularly limited not, it can be selected from the desired material. Itaosae 7 is preferably copper or a copper alloy.
[0062]
　Copper alloy punch 5, the die 6 can be used as a material constituting Itaosae 7, and the cooling tube 9 is preferably chromium copper or alumina dispersed copper. The composition of the chromium copper alloy is preferably 0.4 ~ 1.6% Cr-Cu, more preferably 0.8 ~ 1.2% Cr-Cu, for example, 1.0% Cr-Cu, alumina dispersed copper the composition of the alloy, preferably ~ 1.0% 0.2 Al 2 O 3 -Cu, more preferably ~ 0.7% 0.3 Al 2 O 3 -Cu, eg% Al 0.5 2 O 3 - is Cu.
[0063]
　The distal end of the punch 5, the rivet 8 is arranged. The rivet 8 is what is driven into the plate assembly 4 by the punch 5 may be a general-purpose products of rivets, or the like can be used full tubular rivet. The material of the rivet 8 is not limited in particular as long as it can obtain martensite structure by heat treatment and cooling after bondable and implantation by implanting a plate group 4, for example, machine structural steel, high hardness it can be a steel or the like.
[0064]
　Before implantation, the rivet 8, while being supported by the state or a suitable supporting member supported on the punch 5 may be disposed above the plate assembly 4.
[0065]
　Method for instructing the punch 5 to the support member of rivets 8 or suitably is not particularly limited, for example, may be mechanically held, the punch 5 and the support member, and a material having a magnetic force, the rivet 8 it may be held magnetically attached so.
[0066]
　Die 6 disposed punch 5 and opposite to have a dish-shaped or concave pressing restraining surface 12 corresponding to the shape and size of the legs of the rivet 8 to implant, protruding substantially frustoconical central portion thereof part 13 may have. Top portion of the protruding portion 13 may be slightly lower than the upper surface of the die 6. Root portion side of the projecting portion 13 may have a smooth arcuate surface so as to be continuous to the bottom of the restraint surface 12 pressed.
[0067]
　Plate pairs 4, which are discharged rivets using the apparatus of the present disclosure may be configured by two upper metal plate 2 and the lower metal plate 3 may include three or more of the plurality of metal plates. Metal plate has a plate-shaped portion on at least a portion, as long as the plate-like portion having a stackable parts together, may not be entirely plate shape. The plate assembly 4 is not limited to those composed of separate metal plate, it may be a superposition of those forming the single metal plate into a predetermined shape, such as tubular.
[0068]
　A plurality of metal plates may be the same type of metal plates may be of different types of metal plate. The metal plate can be a metal plate having a high strength steel sheet, it can be an aluminum plate, a magnesium or the like. Steel sheet is preferably a high strength steel plate, more preferably a high-strength steel sheet having a tensile strength of at least 780 MPa. A plurality of metal plates may include a steel plate or one, a high-strength steel sheet having a tensile strength of at least 780MPa may comprise more than one. For example, the plate pair 4 is a plate set to steel all metal plates of the plate assembly 4, the upper metal plate or the lower metal plate and high-strength steel sheet, tensile another metal plate strength and steel less than 780MPa plate assembly, an upper metal plate and an aluminum plate, a lower metal plate plate sets to high-strength steel sheet, or all of the metal plate of the plate assembly 4 may be a plate pair to the aluminum plate. With the apparatus of the present disclosure, it is possible to plate assembly comprising at least one or more high strength steel sheet even better bonding with the above tensile strength 780 MPa.
[0069]
　The thickness of the metal plate is not particularly limited, for example, be a 0.5 ~ 3.0 mm. The thickness of the plate pairs is also not particularly limited and may be, for example, 1.0 ~ 6.0 mm. Also, the presence or absence of plating, well as chemical composition, not particularly limited.
[0070]
　FIG. 1, the flow of current flowing from Itaosae 7 to the die 6 is exemplified by the dotted line arrow, as long electrically heated plate set 4 may be the flow of current flowing from the die 6 to Itaosae 7. Further, the flow of current flowing from the punch 5 in the die 6 is exemplified by the solid arrow, as long electrically heated rivet 8 may be current flow toward the die 6 on the punch 5. The same applies to FIG.
[0071]
　(Embodiment 2)
　With reference to FIG. 1, illustrating a second embodiment is a preferred embodiment.
[0072]
　Cooling system also preferably through a punch 5 until completion driving from the start driving of the rivet, and is configured to cool the rivet. While performing electrical heating plate set 4, while cooling the rivet 8 in the connected cooling device to the punch 5 can be bonded to the plate assembly 4 by implanting rivet 8 in the punch 5.
[0073]
　The plate assembly 4 between the Itaosae 7 and the die 6 when implanting rivet 8 with electrical heating, cooling the rivet 8 through the punch 5, suppressing the softening of the rivet 8 by heat plate pairs 4 it can be, can be performed more stably rivet connection. By cooling the rivet 8, in particular, when the temperature of the plate assembly 4 when implanting the rivet 8 is higher, to suppress softening of the rivets 8, the rivet 8 is prevented from becoming a blind, more it can be performed stably joined.
[0074]
　Cooling of the rivet 8 may be carried out between the end driving from the start driving of the rivet 8. That is, the cooling of the rivet 8 may be started before driving of the rivet 8, may be started driving at the same time as the start, preferably cooling the rivet 8 starts before implantation. Cooling of the rivet 8 may be terminated implanted Upon termination, after completion of implantation may be carried out continuously, but preferably terminates driving ends substantially simultaneously.
[0075]
　Control device provided in the cooling device, it is possible to control the cooling temperature as well as the timing of the cooling start and end. Controller, preferably at the end implantation, more preferably to the end driving from the start driving, so that the temperature of the rivet 8 becomes preferably 3 ~ 50 ° C., more preferably between 5 ~ 30 ° C., controlling the cooling device can do. Temperature of the rivet 8, for example, before the actual joining, pre perform preliminary tests for measuring the temperature of the rivet may have been measuring the temperature of the rivet using a thermocouple.
[0076]
　While performing heat treatment of the rivet 8 may continue the cooling of the rivet 8 through the punch 5, but preferably reduces the cooling of the cooling device, and more preferably stops the cooling device.
[0077]
　(Embodiment 3)
　with reference to FIG. 2, illustrating a third embodiment is a preferred embodiment. Figure 2 shows a schematic sectional view showing the form of mechanical bonding with mechanical joining device comprising a tool steel to a portion of the die. 2 (a) is, in the case of using a tool steel to a portion of the die, a cross-sectional schematic view showing a state of electrically heating the plate pair before driving of the rivet, FIG. 2 (b), die when using a tool steel to a part of a cross-sectional schematic view showing a state of electrically heating the rivet after implantation of the rivet. Mechanical bonding apparatus of Figure 2, except that the die 6 is constituted by a tool steel die 6a and copper or copper alloy die 6b, have a mechanical joint system similar to the configuration of FIG. 1.
[0078]
　To suppress the deformation of the die, of the die, it is effective to increase the strength of the rivet portion facing the (lower part of the portion where the rivet 8 is driven) in between the plate pairs 4. Therefore, as shown in FIG. 2, of the die 6, a portion for restraining a lower metal plate 3 which may be deformed by the rivet 8 is driven by a tool steel die 6a, the strength of the die 6 It can be increased, thereby suppressing the deformation of the die 6.
[0079]
　When driving a rivet into a plate pair, it is energized between the Itaosae and die, or implanted it is energized between the punch and the die when the heat treatment of the rivet, the die is heated. In this case, the material of the die are all tool steels, die tends to soften. Therefore, preferably, the outer peripheral part of the tool steel dies 6a, from the viewpoint of facilitating current flow, composed of copper or a copper alloy.
[0080]
　So as to surround the circumference of the tool steel die 6a, by placing a lower copper or copper alloy die 6b electric resistance, when energized between Itaosae 7 and the die 6, or punch 5 and when energized with the die 6, the current flows preferentially to lower outer peripheral portion of the electric resistance, tool steel die 6a is hardly heated, it is possible to prevent the softening.
[0081]
　When forming part of the die 6 tool steel, of a die 6, the portion facing the rivet 8 in between at least the plate assembly 4 may be composed of tool steel, but in between the plate pairs 4 in Itaosae 7 and may be configured with tool steel a part of the opposing portions. However, among the die 6, as the proportion of the portion constituted of copper or a copper alloy is reduced, since the current tool steel flows through the tool steel is likely to soften during or punch the Itaosae 7 and the die 6 5 and in accordance with the energization amount between the die 6, it is possible to adjust the proportion between the portion constituted by the formed part and the copper or copper alloy tool steel.
[0082]
　The present disclosure also provides a mechanical joining method of implanting rivet by the punch on a plurality of metal plates,
　providing a plurality of metal plates,
　between the punch disposed opposite and die, said plurality of placing superposing a metal plate,
　one end portion of the plate pressing is insertable tubular body the punch inside, is pressed against the punch side of the metal plate of the plurality of metal plates,
　said plurality of metal plates which are pressed by the plate pressing, implanting rivet by the punch,
　before implantation of the rivet, so as to raise the temperature of a plurality of metal plates, the plate retainer and the die through it, to perform the electrical heating of the to a plurality of metal plates, and
　after typing the rivet by the punch, the rivet was electrically heated through the punch and the die, then Cooling the serial rivets,
　including directed to a mechanical joining method.
[0083]
　The bonding method of the present disclosure will be described with reference to FIG.
[0084]
　Prepare a plate set 4 of a plurality of metal plates. Plate assembly 4, the tensile strength may comprise at least one or more of the high strength steel sheet 780 MPa, tensile strength may include only the metal plate below 780 MPa.
[0085]
　The plate assembly 4 is placed on the die 6, the one end portion of Itaosae 7 is a cylindrical body, pressing the metal plate the punch 5 side of the plate assembly 4, the plate set which is pressed by Itaosae 7 4, driving the rivet 8 by the punch 5.
[0086]
　Before driving of the rivet, so as to raise the temperature of the plate assembly 4, through the Itaosae 7 and the die 6, and starts energizing the heating of the plate assembly 4, which electrically heating the plate assembly 4 until the end driving of the rivet 8 .
[0087]
　After implantation of the rivet, via a punch and die, by energizing the rivet is heated to a temperature at which the austenite region, then cooled and the martensite structure and to increase the strength of the rivet.
[0088]
　Preferably, until the completion of implantation from the start driving of the rivet 8 to cool the rivet 8 through the punch 5.
[0089]
　Preferably, among the die, the material of the rivet facing the portion in between at least a plurality of metal plates are tool steel, the material of the outer peripheral portion of the tool steel is copper or a copper alloy.
[0090]
　The configuration of the bonding method of the present disclosure, it is possible to apply the configuration explained in the mechanical bonding apparatus.
Example
[0091]
　(Example 1)
　using a mechanical joining apparatus 1 shown in FIG. 1, it performs a mechanical bonding using rivets plate sets were joint strength test of the bonded joints.
[0092]
　The steel sheet of thickness 1.2mm and upper metal plate tensile strength have a tensile strength of 980MPa as a high-strength steel sheet of more than 780MPa, the steel sheet of thickness 1.6mm tensile strength have a tensile strength of 440MPa as a steel sheet of less than 780MPa upper were prepared plate set 4 to the metal plate.
[0093]
　As shown in FIG. 1 (a), placing the plate assembly 4 on the copper die 6 was stuck with copper plate presser 7 presses the plate group 4. Made hardened steel prepared a full tubular rivet 6mm diameter was held in the punch 5.
[0094]
　The Itaosae 7 and the die 6, a first current of 10kA flows for one second using a power device, where it reaches the 750 ° C., the rivet punch 5 made of 1.0% Cr-Cu having a temperature controller 8 were implanted in joining.
[0095]
　After completion of implantation, stop cooling and heating of the plate assembly 4 of the rivet 8, the punch 5 and the die 6, the current of 8kA flow 0.5 seconds using a second power supply having a temperature controller, rivets 8 was heated to 900 ° C. in the austenite region, then up to 0.99 ° C. at a cooling rate of 30 ° C. / sec, and quenched using a cooling apparatus equipped with a temperature controller.
[0096]
　When checking rivet after the heat treatment, it was confirmed to have a martensitic structure. Then, it was subjected to a joint strength test of the bonded joint, compared with the case of no heat treatment of the rivet, breakage near containing rivets were found to have decreased.
[0097]
　(Example 2)
　the cooling tube 9 shown in the temperature controller connected to Figure 1 to a cooling apparatus equipped with using a punch 5 provided inside, while cooling the rivet 8 to 30 ° C. over the punch 5, the punch 5 by implanted rivets 8, and except that heated plate set 4 up to 780 ° C., was bonded test under the same conditions as in example 1. Without causing rivet damaged, it was possible to perform joining of the plate pairs.
[0098]
　(Example 3)
　using a mechanical joining apparatus 1 shown in FIG. 2, the portion facing the rivet 8 in between the plate pairs 4 and tool steel die 6a, copper on the outer peripheral portion of the die 6a die except that disposed 6b was subjected to bonding tests under the same conditions as in example 1. It is possible to suppress the deformation of the die 6, and cracking of the metal plate, rivets damage, and without causing the rivet blind, it was possible to perform the bonding of the plate sets.
DESCRIPTION OF SYMBOLS
[0099]
　1 mechanical bonding device
　2 upper metal plate
　3 lower metal plate
　4 plate assembly
　5 punch
　5a large diameter portion of the punch
　5b small diameter portion of the punch
　6 die
　6a tool steel die
　6b copper or copper alloy die
　7 Itaosae
　8 rivet
　9 cooling tube
　10 through hole
　11 insulator layer
　12 pressed restraint surface
　13 protrusion
　14 movable plate
　15 holder
　16 compression coil spring
　17 holding plate
　18 molded resin
　19 guide bolt
The scope of the claims

WE CLAIM
[Claim 1]A mechanical bonding apparatus driving a rivet by punching a plurality of metal plates,
　a punch and die,
　and Itaosae,
　a first power supply,
　a second power supply,
　a cooling device,
　comprising a
　said punches and dies, as can be sandwiched between a plurality of metal plates superimposed, is arranged opposite,
　said plates holding is insertable tubular body said punch inside said plate one end of the presser, said plurality of contacting with the punch side of the metal plate of the metal plate, is composed of a plurality of metal plates capable and energizable heating pressed electrode material,
　said punch , consists of a can and energizing heatable electrode material implanted rivet,
　said die, said plurality supportable and said rivet the metal plate is composed of a possible electrical heating electrode material,
　said first power supply device, by the punch Before implanting serial rivets, so as to raise the temperature of said plurality of metal plates, is adapted to energize the plate retainer and said die,
　said second power supply, implanted the rivet by the punch the rivet to heat treated current after said configured to energizing a punch and the die,
　the cooling device is connected to the punch, so as to cool the rivet after the heat treatment of the rivet It is configured,
　the mechanical bonding apparatus.
[Claim 2]
　The cooling device further until completion driving from the start driving of the rivet, and is configured to cool the rivet, mechanical bonding apparatus according to claim 1.
[Claim 3]
　Among the die is sandwiched therebetween the material is tool steel of the rivet facing the portion between at least the plurality of metal plates, the material of the outer peripheral portion of the tool steel is copper or a copper alloy, according to claim 1 or mechanical bonding apparatus according to 2.
[Claim 4]
　A mechanical bonding method of implanting rivet by the punch on a plurality of metal plates,
　providing a plurality of metal plates,
　between the punch and die arranged to face, overlapping the plurality of metal plates placing together,
　one end of the plate presser is insertable tubular body the punch inside, is pressed against the punch side of the metal plate of the plurality of metal plates,
　pressed by the plate pressing said plurality of metal plates which are, implanting rivet by the punch,
　before implantation of the rivet, so as to raise the temperature of said plurality of metal plates, through the plate retainer and said die, said plurality performing the electrical heating of the sheets to the metal plate, and
　after typing the rivet by the punch, the rivet was electrically heated through the punch and the die, then the rivet To retirement,
　including, mechanical joining method.
[Claim 5]
　Until completion driving from the start driving of the rivet, further comprising a mechanical bonding method according to claim 4 to cool the rivet through the punch.
[Claim 6]
　Among the die, the material of the portion facing the rivet in between at least the plurality of metal plates are tool steel, the material of the outer peripheral portion of the tool steel is copper or a copper alloy, according to claim 4 or mechanical bonding method according to 5.