JP2011245512A - Method for joining metal members - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure high joint strength with a minimized joint energy.SOLUTION: First and second outer diameter portions 11, 12 of a second metal member (10) are allowed to abut respectively on first and second inner diameter portions 4, 5 of a first metal member (1), and the first metal member (1) and the second metal member (10) are electrified by use of a pair of electrodes 21, 22 while being pressed axially, whereby a first joint portion P1 in which the first inner diameter portion 4 and the first outer diameter portion 11 are joined together and a second joint portion in which the second inner diameter portion 5 and the second outer diameter portion 12 are joined together are formed between both the members (1, 10) while forming a gap portion 15 between both the joint portions P1, P2. Of a contact portion C1 between the first outer diameter portion 11 and the first inner diameter portion 4 and a contact portion C2 between the second outer diameter portion 12 and the second inner diameter portion 5, an overlap margin (S1) of the contact portion which has high temperature by the electrification is set larger than an overlap margin (S2) of the other contact portion.

Description

  The present invention relates to a first metal member provided with an opening and a second metal member having an outer peripheral wall part that can partially contact the inner peripheral wall part of the first metal member surrounding the opening. The present invention relates to a method of joining by resistance heat generation by energization while applying pressure in the direction.

  Conventionally, as a kind of so-called ring mash joining method, a joining method shown in the following Patent Document 1 is known. Specifically, in the method of Patent Document 1 below, a hollow first metal member and a second metal member having an outer diameter slightly larger than the inner diameter of the first metal member are overlapped in the axial direction, and in the same direction. By applying a welding current in a state where pressure is applied to the inner surface of the first metal member, the inner peripheral surface of the first metal member and the outer peripheral surface of the second metal member are joined.

  In this case, the form of joining between the first metal member and the second metal member is not fusion melting but diffusion bonding. That is, by applying current to both the metal members while applying pressure, the metal at the contact portion is softened to generate plastic flow, and the new metal surfaces are metallurgically joined together.

JP 2004-17048 A

  According to the ring mash joining method as shown in the above-mentioned Patent Document 1, there is no occurrence of carbide segregation due to melting, solidification cracking due to thermal influence, or the like as compared with general melt joining such as arc welding. There is an advantage that the time required for welding is very short.

  However, in the method disclosed in Patent Document 1, when the bonding area between the first metal member and the second metal member is increased for the purpose of further increasing the bonding strength, There is a problem that it is necessary to increase the applied pressure and the current value, leading to an increase in the size of the equipment. For this reason, it has been required to further improve the bonding strength while keeping the energy required for bonding as low as possible.

  This invention is made | formed in view of the above situations, and it aims at providing the joining method of the metal member which can obtain high joining strength with little joining energy.

  In order to solve the above-mentioned problems, the present invention provides a first metal member provided with an opening and an outer peripheral wall part that can partially contact the inner peripheral wall part of the first metal member surrounding the opening. A second metal member having a predetermined inner diameter on an inner peripheral wall portion of the first metal member; A second inner diameter portion having a larger inner diameter than the first inner diameter portion and the outer diameter wall portion of the second metal member having a larger outer diameter by a predetermined overlap margin than the first inner diameter portion and the second inner diameter portion. An outer diameter portion and a second outer diameter portion are formed, and among the contact portion between the first outer diameter portion and the first inner diameter portion, and the contact portion between the second outer diameter portion and the second inner diameter portion, during energization The overlap margin of the contact portion that is hotter is larger than the overlap margin of the other contact portion The first metal member and the second metal member are set in a state where the first and second outer diameter portions of the second metal member are in contact with the first and second inner diameter portions of the first metal member, respectively. And a first joint part in which the first inner diameter part and the first outer diameter part are joined between the two metal members by applying current while pressing in the axial direction using a pair of electrodes, A second joint portion is formed by joining the second inner diameter portion and the second outer diameter portion, and a gap portion where the metals do not contact each other is formed over a predetermined axial length between the two joint portions. (Claim 1).

  According to the joining method of the present invention, the inner peripheral wall portion of the first metal member and the outer peripheral wall portion of the second metal member are formed in steps, and by forming two joint portions spaced apart from each other, Even if the axial length of each joint (joint length) is not increased unnecessarily, an excellent joint structure that is particularly resistant to bending can be constructed, and the joint strength is effectively avoided while avoiding an increase in joint energy. Can be improved.

  In particular, in the present invention, when the first metal member and the second metal member are joined, the contact portion between the first outer diameter portion and the first inner diameter portion, and the second outer diameter portion and the second inner diameter portion. Among the contact parts, the overlap margin of the contact section that becomes hotter when energized is set to be relatively large, so a high-quality joint based on the appropriate overlap margin according to the temperature rise width of the contact section The joint strength between the first metal member and the second metal member can be improved more effectively.

  Specifically, in order to increase the overlap margin of the contact portion that becomes hotter when energized, the contact portion between the first outer diameter portion and the first inner diameter portion, and the second outer diameter portion and the second Of the contact portions with the inner diameter portion, the overlap margin of the contact portion having the shorter distance from the electrode may be set larger than the overlap margin of the other contact portion.

  According to this aspect, by setting the overlap margin of the contact portion that is short in distance to the electrode and is likely to become hot when energized to be larger than the other overlap margin, it is possible to appropriately improve the quality of the joint portion. Can be planned.

  On the other hand, when the first metal member and the second metal member are made of different metals having different electric resistance values, the contact portion between the first outer diameter portion and the first inner diameter portion, and the second outer diameter portion, Of the contact portions with the second inner diameter portion, an overlap margin of a contact portion having a larger current flowing during energization may be set larger than an overlap margin of the other contact portion.

  According to this aspect, due to the difference in the electric resistance value, the overlapping portion of the contact portion that has a large current value when energized and is likely to be heated to a high temperature is set to be larger than the other overlapping portion. Can be improved appropriately.

  The joining method of the present invention can be applied to joining various metal members. As a specific example, the first metal member is a clutch cone used in a manual transmission, and the second metal member is the clutch. In the case where the gear is joined to the cone, the joining method of the present invention can be suitably applied (claim 4).

  Also, the joining method of the present invention can be suitably applied when the first metal member is a gear used for a differential mechanism and the second metal member is a differential case joined to the gear. (Claim 5).

  As described above, according to the method for joining metal members of the present invention, high joining strength can be obtained with little joining energy.

It is sectional drawing which shows the state before joining of the clutch cone and helical gear used as joining object in 1st Embodiment of this invention. It is a figure which shows schematic structure of the joining apparatus used when joining the said clutch cone and a helical gear. It is the A section enlarged view of FIG. FIG. 4 is a view corresponding to FIG. 3 showing a state where the joining is completed. It is a figure for demonstrating the condition where a bending moment is added to the said clutch cone. It is a figure for demonstrating the modification of the said 1st Embodiment, (a) has shown the state before joining, (b) has each shown the state after joining. It is sectional drawing which shows the state before joining of the ring gear used as joining object in 2nd Embodiment of this invention, and a differential case. It is a figure which shows schematic structure of the joining apparatus used when joining the said ring gear and a differential case. It is the B section enlarged view of FIG. FIG. 10 is a view corresponding to FIG. 9 showing a state where the joining is completed. It is a figure for demonstrating the modification of the said 2nd Embodiment. It is a figure which shows the state after joining of the components shown by FIG.

<Embodiment 1>
First, a first embodiment of the present invention will be described. As shown in FIG. 1, in this embodiment, the clutch cone 1 and the helical gear 10 which are parts for vehicles are joined based on the joining method of this invention.

  The helical gear 10 is a gear part for a manual transmission and corresponds to a second metal member according to the present invention. The material of the helical gear 10 is steel, and a specific example thereof is carburized and hardened steel such as SCR420H.

  The helical gear 10 is formed of a cylindrical body having an axially penetrating opening formed at the center, and the outer peripheral wall has a multi-stage shape with a plurality of large and small outer diameters. Specifically, a first outer diameter portion 11 having an outer diameter Y1 and a second outer diameter portion 12 having an outer diameter Y2 larger than the outer diameter Y1 are formed on the outer peripheral wall portion of the helical gear 10. Yes. Further, a gear portion 13 made of screw teeth is formed on the outermost peripheral portion having a diameter larger than that of the second outer diameter portion 12.

  The clutch cone 1 is a part used for the rotation synchronization of the manual transmission, and corresponds to the first metal member according to the present invention. The material of the clutch cone 1 is steel, and a specific example thereof is carburized and hardened steel such as SCR420H.

  The clutch cone 1 is formed of a cylindrical body having an axially penetrating opening 2 formed in the center, and a tapered cone surface 3 is formed on the outer peripheral surface thereof so as to be pressed against a synchronizer ring (not shown). Yes. A first inner diameter portion 4 having an inner diameter X1 and a second inner diameter portion 5 having an inner diameter X2 larger than the inner diameter X1 are formed on the inner peripheral wall portion of the clutch cone 1 surrounding the opening 2.

  Regarding the relationship between the inner diameters X1 and X2 of the clutch cone 1 and the outer diameters Y1 and Y2 of the helical gear 10, the outer diameter Y1 of the first outer diameter portion 11 is slightly smaller than the inner diameter X1 of the first inner diameter portion 4. The outer diameter Y2 of the second outer diameter portion 12 is slightly larger than the inner diameter X2 of the second inner diameter portion 5. In addition, as shown in FIG. 3 to be described later, with respect to the overlap margin which is a radial difference between the outer portions 11 and 12 and the inner diameter portions 4 and 5, the first outer diameter portion 11 and the first inner diameter portion 4 Is set so that S1> S2, where S1 is the overlap margin and S2 is the overlap margin of the second outer diameter portion 12 and the second inner diameter portion 5. Further, in this case, the difference in diameter is 2S1 and 2S2, respectively, (the outer diameter Y1 of the first outer diameter portion 11) = (the inner diameter X1 of the first inner diameter portion 4) + 2S1, (the outer diameter of the second outer diameter portion 12) Diameter Y2) = (Inner diameter X2 of second inner diameter portion 5) + 2S2.

  FIG. 2 is a diagram showing a schematic configuration of a joining device 20 used when joining the clutch cone 1 and the helical gear 10. As shown in the figure, the bonding apparatus 20 includes an upper electrode 21 and a lower electrode 22, an unshown pressurizing mechanism that pressurizes the electrodes 21 and 22 in the axial direction (vertical direction in FIG. 2), , 22 and a power supply device 23 for supplying a high current for bonding.

  Such joining using the joining device 20 is performed by inserting the part of the helical gear 10 into the opening 2 of the clutch cone 1 and temporarily fixing the two members 1 by the upper electrode 21 and the lower electrode 22. , 10 by energizing while pressing in the axial direction. FIG. 2 illustrates a case where the upper electrode 21 and the lower electrode 22 are disposed to face each other in the vertical direction, and the clutch cone 1 and the helical gear 10 are sandwiched therebetween to be joined. Of course, it is also possible to join them in a state of being opposed to each other in the horizontal direction.

  The procedure for joining the clutch cone 1 and the helical gear 10 will be described in more detail. In order to join the clutch cone 1 and the helical gear 10, first, the helical gear 10 is installed on the lower electrode 22 in a posture in which the second outer diameter portion 12 is lower than the first outer diameter portion 11. Then, the clutch cone 1 is approached from above with respect to the helical gear 10 in this state. The posture of the clutch cone 1 at this time is a posture in which the second inner diameter portion 5 is lower than the first inner diameter portion 4. As a result, the helical gear 10 is inserted into the opening 2 of the clutch cone 1 before the first outer diameter portion 11.

  FIG. 3 is an enlarged view of a portion A in FIG. As described above, the outer diameter Y1 of the first outer diameter portion 11 of the helical gear 10 is larger by the overlap margin S1 than the inner diameter X1 of the first inner diameter portion 4 of the clutch cone 1 (Y1 = X1 + 2S1). The outer diameter Y2 of the second outer diameter portion 12 of the helical gear 10 is larger than the inner diameter X2 of the second inner diameter portion 5 of the clutch cone 1 by the overlap margin S2 (Y2 = X2 + 2S2). For this reason, when the helical gear 10 is inserted into the clutch cone 1, the outermost peripheral portion of the first outer diameter portion 11 contacts the lower end of the first inner diameter portion 4, and the outermost peripheral portion of the second outer diameter portion 12 is It contacts the lower end of the second inner diameter portion 5. At this time, the first outer diameter portion 11 and the first inner diameter portion 4, and the second outer diameter portion 12 and the second inner diameter portion are set by setting the axial lengths of the first outer diameter portion 11 and the second inner diameter portion 5. The part 5 is in contact with the same at the same time.

  When the clutch cone 1 is temporarily fixed on the helical gear 10 as described above, the clutch cone 1 and the helical gear 10 are sandwiched and pressurized by the upper electrode 21 and the lower electrode 22 from above and below, and the both electrodes 21 are pressed. , 22 is applied with a bonding voltage. Specifically, the upper electrode 21 is approached from above with respect to the clutch cone 1 and the helical gear 10 temporarily fixed on the lower electrode 22, and the lower end thereof is brought into contact with the upper end surface of the helical gear 10. In this state, a predetermined pressure is applied to the electrodes 21 and 22 in the approaching direction (axial direction). Further, by operating the power supply device 23 in accordance with this, a voltage for joining is applied to both the electrodes 21 and 22.

  A large current instantaneously flows between the electrodes 21 and 22 via the clutch cone 1 and the helical gear 10 in response to the application of the voltage as described above. At this time, the clutch cone 1 and the helical gear 10 include a contact portion C1 between the first inner diameter portion 4 and the first outer diameter portion 11, and a contact portion C2 between the second inner diameter portion 5 and the second outer diameter portion 12. Therefore, the current flows through the two contact portions C1 and C2.

  Then, resistance heat generation due to energization occurs, and metal softening and plastic flow occur at both contact portions C1 and C2. At this time, since the pressurization by the electrodes 21 and 22 is continued, the clutch cone 1 is gradually pushed downward with respect to the helical gear 10 as the metal is softened. As a result, the contact area between the clutch cone 1 and the helical gear 10 (that is, each contact area between the first inner diameter portion 4 and the first outer diameter portion 11, and the second inner diameter portion 5 and the second outer diameter portion 12) increases. The area where the metal softens also increases. In the following, the contact portion C1 between the first inner diameter portion 4 and the first outer diameter portion 11 is referred to as the upper contact portion C1, and the contact portion C2 between the second inner diameter portion 5 and the second outer diameter portion 12 is referred to. It may be referred to as a lower contact portion C2.

  Here, in the contact portions C1 and C2 that are heated and softened by energization and pressurization as described above, the upper contact portion C1 that is a contact portion between the first inner diameter portion 4 and the first outer diameter portion 11 is used. The temperature tends to be higher than the temperature of the lower contact portion C2, which is a contact portion between the second inner diameter portion 5 and the second outer diameter portion 12. This is because the distance from the upper contact portion C1 to the upper electrode 21 is shorter than the distance from the lower contact portion C2 to the lower electrode 22 (FIG. 2).

  That is, in the upper contact portion C1 and the lower contact portion C2, heat is generated due to the contact resistance between the metals. Of these, the upper contact portion C1 has a short distance from the upper electrode 21, and thus In addition to such resistance heat generation, the electrode 21 is easily affected by heat generation due to contact resistance between the electrode 21 and the upper surface of the clutch cone 1 and tends to have a higher temperature. In FIG. 3, the upper end portion of the clutch cone 1 that becomes particularly hot due to the contact resistance with the upper electrode 21 is indicated by a symbol Q (hereinafter referred to as a high temperature portion Q). Since the upper contact portion C1 is close to the high temperature portion Q in position, the upper contact portion C1 is heated higher than the lower contact portion C2 due to the thermal influence from the portion Q.

  In consideration of such a temperature difference between the upper contact portion C1 and the lower contact portion C2, in this embodiment, as described above, the overlap margin S1 of the upper contact portion C1 is changed to the overlap of the lower contact portion C2. It is set larger than the cost S2 (S1> S2). That is, the upper contact portion C1, which is a contact portion between the first outer diameter portion 11 and the first inner diameter portion 4, is closer to the high temperature portion Q, and the second outer diameter portion 12 and the second inner diameter portion 5 are in contact with each other. Since the temperature is higher than that of the lower contact portion C2, which is a portion, the softening range of the upper contact portion C1 is wider than the softening range of the lower contact portion C2 in the range where the metal is softened. Therefore, in this embodiment, in order to ensure an appropriate overlap margin corresponding to the softening range of the metal, the overlap margin S1 which is a radial difference between the first outer diameter portion 11 and the first inner diameter portion 4 is increased. 2 The overlap margin S2, which is a radial difference between the outer diameter portion 12 and the second inner diameter portion 5, is reduced. For example, S1 = 0.3 mm and S2 = 0.15 mm.

  FIG. 4 shows a state in which the connection between the clutch cone 1 and the helical gear 10 is completed as a result of the energization and pressurization using the upper electrode 21 and the lower electrode 22 being continued. That is, when the joining is completed, the clutch cone 1 is pushed downward until the protrusion 6 provided on the lower surface of the clutch cone 1 contacts the helical gear 10, and as shown in FIG. When the two inner diameter portions 4 and 5 and the first and second outer diameter portions 11 and 12 of the helical gear 10 are in surface contact with each other over a predetermined axial length, the energization between the electrodes 21 and 22 is performed. Is stopped. Thereby, the metal of each said contact surface resolidifies, and two junction part P1, P2 as shown in the figure is formed.

  That is, metal softening and plastic flow occur on the contact surfaces of the first inner diameter portion 4 and the first outer diameter portion 11, and the second inner diameter portion 5 and the second outer diameter portion 12, thereby causing an oxide film or When the foreign matter is removed and the energization is stopped in this state, the softened portion is solidified again, and the new metal surfaces are metallurgically bonded (diffusion bonding). Thereby, the first joint P1 is formed between the first inner diameter part 4 and the first outer diameter part 11, and the second joint part is formed between the second inner diameter part 5 and the second outer diameter part 12. P2 is formed.

  By passing through the above processes, joining of the clutch cone 1 and the helical gear 10 is completed. Between the first joint P1 and the second joint P2 formed in this case, there is a gap 15 where the metals do not contact each other over a predetermined axial length. That is, the first and second inner diameter portions 4 and 5 of the clutch cone 1 and the first and second of the helical gear 10 are arranged so that the first joint portion P1 and the second joint portion P2 are separated from each other in the axial direction. The dimensional relationship between the outer diameter portions 11 and 12 (the relationship between the axial lengths) is set, and by setting such a dimensional relationship, there is a gap between the joint portions P1 and P2 in the state after joining. A portion 15 is formed.

  As described above, in the first embodiment of the present invention, when the clutch cone 1 and the helical gear 10 are joined, first, the first inner diameter portion 4 having the inner diameter X1 is formed on the inner peripheral wall portion of the clutch cone 1. The outer diameter of the helical gear 10 is larger by the overlap margins S1 and S2 than the inner diameters X1 and X2 (outer diameter Y1, The first outer diameter portion 11 and the second outer diameter portion 12 (of Y2) are formed. The first and second outer diameter portions 11 and 12 of the helical gear 10 are brought into contact with the first and second inner diameter portions 4 and 5 of the clutch cone 1, respectively, and the clutch cone 1 and the helical gear 10 are also brought into contact with each other. The first inner diameter portion 4 and the first outer diameter portion 11 are joined between the members 1 and 10 by energizing them while applying pressure in the axial direction using a pair of electrodes 21 and 22. The first joint portion P1 and the second joint portion P2 in which the second inner diameter portion 5 and the second outer diameter portion 12 are joined are formed, and the metal is between the joint portions P1 and P2. The non-contact gap 15 is formed over a predetermined axial length. According to such a configuration, there is an advantage that a high bonding strength can be obtained with a small bonding energy.

  That is, in the first embodiment, the inner peripheral wall portion of the clutch cone 1 and the outer peripheral wall portion of the helical gear 10 are formed in steps, so that the two joint portions P1 and P2 are formed apart from each other, and a gap is formed between them. Since it is the portion 15, even if the axial length (joint length) of each of the joints P1 and P2 is not increased unnecessarily, it is possible to construct an excellent joint structure that is particularly resistant to bending and increase the joint energy. There is an advantage that the bonding strength can be effectively improved while avoiding the problem.

  For example, if the purpose is merely to increase the bonding strength, one bonding portion having a long bonding length is formed without dividing the bonding portion into two (P1, P2) as in the first embodiment. The joint strength can be increased. However, in such a case, a current value and a pressing force required at the time of joining increase, resulting in an increase in equipment size and cost.

  On the other hand, when the two joint portions P1 and P2 separated in the axial direction are formed as in the first embodiment, for example, the joint portions P1 and P2 are continuous in the axial direction. In comparison, since the section modulus of the joint portion increases, especially when a bending moment M as shown in FIG. 5 acts on the clutch cone 1, the force acting on the joint portions P1 and P2 is reduced, and the bending rigidity is reduced. More improved. The clutch cone 1 used for the rotation synchronization of the manual transmission receives forces in various directions from a synchronizer ring (not shown) that is pressed against the tapered cone surface 3. Improvements can improve the reliability of manual transmissions.

  Furthermore, in the first embodiment, as shown in FIG. 3, when the clutch cone 1 and the helical gear 10 are joined, the distance between the upper electrode 21 is short and the upper contact portion that is likely to become hotter when energized. The overlap margin S1 of C1 (the contact portion between the first outer diameter portion 11 and the first inner diameter portion 4) is the same as that of the lower contact portion C2 (the contact portion between the second outer diameter portion 12 and the second inner diameter portion 5). It was set to be larger than the overlap margin S2. Thus, by setting an appropriate overlap margin according to the temperature rise width of the contact portion, each joint between the first and second outer diameter portions 11 and 12 and the first and second inner diameter portions 4 and 5 is performed. The quality of the parts P1 and P2 can be ensured satisfactorily, and the joining strength between the clutch cone 1 and the helical gear 10 can be sufficiently increased.

  For example, the contact portion C1 between the first outer diameter portion 11 and the first inner diameter portion 4 has a large temperature rise during energization, and a wider range of metal softens. Therefore, the overlap margin S1 of the contact portion C1 If it is too small, a phenomenon such as sputtering in which the molten metal scatters occurs, and there is a possibility that diffusion bonding between the metals becomes incomplete. On the other hand, in the contact portion C2 between the second outer diameter portion 12 and the second outer diameter portion 5, the temperature is relatively low and the range in which the metal softens is narrow, so the overlap margin S2 of the contact portion C2 is too large. Then, it becomes the same state as mere press-fitting, and there is a possibility that diffusion bonding between metals is incomplete.

  In contrast, in the first embodiment, the overlap margin S1 of the contact portion C1 between the first outer diameter portion 11 and the first inner diameter portion 4 is increased, and the second outer diameter portion 12 and the second outer diameter portion 5 are Since the overlap margin S2 of the contact portion C2 is reduced, the temperature rise width of the contact portions C1 and C2 and the overlap margins S1 and S2 are well balanced, and the above situation can be avoided appropriately. The second outer diameter portions 11 and 12 and the first and second inner diameter portions 4 and 5 can be bonded by good diffusion bonding. As a result, good-quality joints P1 and P2 (FIG. 4) having sufficient strength can be formed, and the joint strength between the clutch cone 1 and the helical gear 10 can be improved more effectively.

  In the first embodiment, the clutch cone 1 and the helical gear 10 are joined via the two joints P1 and P2 that are spaced apart in the axial direction. You may join the clutch cone 1 and the helical gear 10 through the location of a part or more. 6 (a) and 6 (b) illustrate the case where the joints are set at three locations (P1 ′, P2 ′, P3 ′). FIG. 6 (a) shows the state before joining. (B) has shown the state after joining, respectively.

  In this case, the overlap margins S1 ′, S2 ′, S3 ′ of the contact portions between the clutch cone 1 and the helical gear 10 are made larger as they are closer to the upper electrode 21, as shown in FIG. '> S2'> S3 '. As described above, by increasing the overlap margin of the contact portion that is close to the electrode and easily becomes high temperature, the quality of the joint portions P1 ′, P2 ′, and P3 ′ is appropriately improved as in the first embodiment. be able to.

  Further, in the first embodiment, as shown in FIG. 3, the contact portion C1 between the first outer diameter portion 11 and the first inner diameter portion 4 is quite close to the upper electrode 21 and is likely to become high temperature when energized. Therefore, the overlap margin S1 of the contact portion C1 between the first outer diameter portion 11 and the first inner diameter portion 4 is greater than the overlap margin S2 of the contact portion C2 between the second outer diameter portion 12 and the second inner diameter portion 5. However, since the positional relationship between the upper electrode 21 and the lower electrode 22 and the contact portions C1 and C2 is different, the contact portion C2 between the second outer diameter portion 12 and the second inner diameter portion 5 is When the temperature is higher than the contact portion C1 between the outer diameter portion 11 and the first inner diameter portion 4, the overlap margin S2 of the contact portion C2 is set to be larger than the overlap margin S1 of the contact portion C1. It should be larger.

  In the above embodiment, the case where the steel clutch cone 1 and the steel helical gear 10 are joined is described as an example. However, the joining method of the present invention can be applied to other metal parts. Of course, it is applicable and the material is not limited to steel. Since the joining method of the present invention is joined by softening and plastic flow of metal, there are fewer restrictions on materials than in the case of fusion joining such as arc welding and laser welding, and application to various materials can be expected. .

Next, an example where the materials to be joined are different will be described as a second embodiment of the present invention.
<Embodiment 2>
In 2nd Embodiment of this invention, as shown in FIG. 7, the ring gear 50 and differential case 60 which are components for vehicles are joined based on the joining method of this invention.

  The differential case 60 is a case that houses a pinion gear and a side gear of a differential mechanism, and corresponds to a second metal member according to the present invention. The material of the differential case 10 is cast iron, and specific examples thereof include spheroidal graphite cast iron such as FCD450 and FCD550.

  The differential case 60 is formed of a hollow multi-stage member having an axial intermediate portion swelled more than both end portions. A first outer diameter portion 61 having an outer diameter Y11 and a second outer diameter portion 62 having an outer diameter Y12 larger than the outer diameter Y11 are formed on an outer peripheral wall portion near one end in the axial direction of the differential case 60. Yes.

  The ring gear 50 is a gear part that receives the driving force transmitted from the transmission, and corresponds to a first metal member according to the present invention. The material of the ring gear 50 is steel, and a specific example thereof is carburized and hardened steel such as SCR420H.

  The ring gear 50 is made of a ring-shaped member having an opening 52 penetrating in the axial direction (thickness direction) formed at the center, and a gear portion 53 that meshes with an output gear of the transmission at the outermost peripheral portion. Is formed. A first inner diameter portion 54 having an inner diameter X11 and a second inner diameter portion 55 having an inner diameter X12 larger than the inner diameter X11 are formed on the inner peripheral wall portion of the ring gear 1 surrounding the opening 52.

  Regarding the relationship between the inner diameters X11 and X12 of the ring gear 50 and the outer diameters Y11 and Y12 of the differential case 60, the outer diameter Y11 of the first outer diameter portion 61 is slightly larger than the inner diameter X11 of the first inner diameter portion 54. The outer diameter Y2 of the second outer diameter portion 12 is slightly larger than the inner diameter X2 of the second inner diameter portion 5. In addition, as shown in FIG. 9 to be described later, with respect to the overlap margin which is a radial difference between the outer portions 61 and 62 and the inner diameter portions 54 and 55, the first outer diameter portion 61 and the first inner diameter portion 54 Is set so that S12> S11, where S11 is the overlap allowance and S12 is the overlap allowance between the second outer diameter portion 62 and the second inner diameter portion 55. In this case, the difference in diameter is 2S11 and 2S12, respectively, (the outer diameter Y11 of the first outer diameter portion 61) = (the inner diameter X11 of the first inner diameter portion 54) + 2S11, (the outer diameter of the second outer diameter portion 62) Diameter Y12) = (Inner diameter X12 of second inner diameter portion 55) + 2S12.

  FIG. 8 is a diagram showing a schematic configuration of a joining device 70 used when joining the ring gear 50 and the differential case 60. As shown in this figure, the bonding apparatus 70 in the present embodiment has basically the same configuration as the bonding apparatus 20 used in the previous first embodiment, and includes an upper electrode 71 and a lower electrode 72, A pressing mechanism (not shown) that pressurizes the electrodes 71 and 72 in the axial direction (vertical direction in FIG. 8) and a power supply device 73 that supplies a high current for bonding to the electrodes 71 and 72 are provided.

  Such joining using the joining device 70 is performed by inserting both the members 50, the upper electrode 71 and the lower electrode 72 in a state where a part of the differential case 60 is inserted and temporarily fixed in the opening 52 of the ring gear 50. This is done by energizing 60 while pressing 60 in the axial direction. FIG. 8 illustrates a case where the upper electrode 71 and the lower electrode 72 are arranged opposite to each other in the vertical direction, and the ring gear 50 and the differential case 60 are sandwiched therebetween to be joined. It is of course possible to join in a state of being opposed to each other in the horizontal direction.

  The procedure for joining the ring gear 50 and the differential case 60 will be described in more detail. In order to join the ring gear 50 and the differential case 60, first, the ring gear 50 is installed on the lower electrode 72 in such a posture that the first inner diameter portion 54 is lower than the second inner diameter portion 55. Then, the differential case 60 is made to approach the ring gear 50 in this state from above. The posture of the differential case 60 at this time is a posture in which the first outer diameter portion 61 is lower than the second outer diameter portion 62. Thus, the differential case 60 is inserted into the opening 52 of the ring gear 50 first from the first outer diameter portion 61.

  FIG. 9 is an enlarged view of a portion B in FIG. As described above, the outer diameter Y11 of the first outer diameter portion 61 of the differential case 60 is larger by the overlap margin S11 than the inner diameter X11 of the first inner diameter portion 54 of the ring gear 50 (Y11 = X11 + 2S11). The outer diameter Y12 of the second outer diameter portion 62 of the differential case 60 is larger by the overlap margin S12 than the inner diameter X12 of the second inner diameter portion 55 of the ring gear 50 (Y12 = X12 + 2S12). For this reason, when the differential case 60 is inserted into the ring gear 50, the outermost peripheral portion of the first outer diameter portion 61 contacts the upper end of the first inner diameter portion 54, and the outermost peripheral portion of the second outer diameter portion 62 is 2 abuts on the upper end of the inner diameter portion 55. At this time, the first outer diameter portion 61 and the first inner diameter portion 54 and the second outer diameter portion 62 and the second inner diameter portion are set by setting the axial lengths of the first outer diameter portion 61, the second inner diameter portion 55, and the like. The portion 55 is in contact with the portion 55 at the same time.

  When the differential case 60 is temporarily fixed on the ring gear 50 as described above, the ring gear 50 and the differential case 60 are sandwiched and pressurized by the upper electrode 71 and the lower electrode 72 from above and below, and both the electrodes 71 and 72 are pressed. A voltage for bonding is applied to. Specifically, the upper electrode 71 is approached from above with respect to the ring gear 50 and the differential case 60 temporarily fixed on the lower electrode 72, and the lower end thereof is brought into contact with the inner wall surface of the differential case 60, and the state thereof Then, a predetermined pressing force is applied to the electrodes 71 and 72 in the approaching direction (axial direction). In addition, by operating the power supply device 73 in accordance with this, a voltage for bonding is applied to the electrodes 71 and 72.

  A large current instantaneously flows between the electrodes 71 and 72 through the ring gear 50 and the differential case 60 in accordance with the application of the voltage as described above. At this time, the ring gear 50 and the differential case 60 include a contact portion C11 between the first inner diameter portion 54 and the first outer diameter portion 61 and a contact portion C12 between the second inner diameter portion 55 and the second outer diameter portion 62. Since they are in contact at two places, the current flows through the two contact portions C11 and C12.

  Then, resistance heat generation due to energization occurs, and metal softening and plastic flow occur at both contact portions C11 and C12. At this time, since the pressurization by the electrodes 71 and 72 is continued, the differential case 60 is gradually pushed downward with respect to the ring gear 50 as the metal is softened. Thereby, the contact area between the ring gear 50 and the differential case 60 (that is, each contact area between the first inner diameter portion 54 and the first outer diameter portion 61 and the second inner diameter portion 55 and the second outer diameter portion 62) is increased. The area where the metal softens also increases. Hereinafter, the contact portion C11 between the first inner diameter portion 54 and the first outer diameter portion 61 is referred to as the lower contact portion C11, and the contact portion C12 between the second inner diameter portion 55 and the second outer diameter portion 62. May be referred to as the upper contact portion C12.

  Here, in the contact portions C11 and C12 that are heated and softened by energization and pressurization as described above, the upper contact portion C12 that is a contact portion between the second inner diameter portion 55 and the second outer diameter portion 62 is used. The temperature tends to be higher than the temperature of the lower contact portion C11 that is a contact portion between the first inner diameter portion 54 and the first outer diameter portion 61. This is because the current I2 passing through the upper contact portion C12 has a larger value than the current I1 passing through the lower contact portion C11.

  That is, when the ring gear 50 to be joined in the present embodiment and the differential case 60 are compared, the electric resistance value of the differential case 60 made of cast iron is larger than that of the ring gear 50 made of steel. On the other hand, comparing the path of the current I2 passing through the upper contact portion C12 and the path of the current I1 passing through the lower contact portion C11, the path of the current I1 is longer in the high-resistance differential case 60. Since it passes over a distance, it is a path through which current hardly flows. Therefore, the value of the current I2 becomes larger than the value of the current I1, and the upper contact portion C12 through which the current I2 flows becomes higher in temperature than the lower contact portion C11 through which the current I1 flows.

  As described in the first embodiment, the temperature difference between the upper contact portion C12 and the lower contact portion C11 may be related to the distance between the upper electrode 71 and the lower electrode 72. In the embodiment, since there is no great difference in the distance between the upper electrode 71 and the upper contact portion C12 and the distance between the lower electrode 72 and the lower contact portion C11, the temperature difference between the two contact portions C11 and C12 is mainly a current. This is considered to be due to the difference between the values I1 and I2.

  In view of the temperature difference between the upper contact portion C12 and the lower contact portion C11 as described above, in the present embodiment, as described above, the overlap margin S12 of the upper contact portion C12 is set to be greater than that of the lower contact portion C11. It is set larger than the lap margin S11 (S12> S11). That is, the upper outer contact portion C12 that is the contact portion between the second outer diameter portion 62 and the second inner diameter portion 55 causes the higher current I2 to flow, so that the first outer diameter portion 61 and the first inner diameter portion 54 Therefore, the softening range at the upper contact portion C12 is wider than the softening range at the lower contact portion C11. Therefore, in this embodiment, in order to ensure an appropriate overlap margin corresponding to the softening range of the metal, the overlap margin S12 which is a radial difference between the second outer diameter portion 62 and the second inner diameter portion 55 is increased. The overlap margin S11, which is the radius difference between the first outer diameter portion 61 and the first inner diameter portion 54, is reduced. For example, S12 = 0.5 mm and S11 = 0.2 mm.

  FIG. 10 shows a state where joining of the ring gear 50 and the differential case 60 is completed as a result of continuing energization and pressurization using the upper electrode 71 and the lower electrode 72. That is, when the joining is completed, the differential case 60 is pushed downward until the lower end of the first outer diameter portion 61 of the differential case 60 comes into contact with the lower electrode 72, and as shown in FIG. When the inner diameter portions 54 and 55 and the first and second outer diameter portions 61 and 62 of the differential case 60 come into surface contact over a predetermined axial length, the energization between the electrodes 71 and 72 is stopped. Is done. Thereby, the metal of each said contact surface resolidifies, and two junction part P11, P12 as shown to the same figure is formed.

  That is, metal softening and plastic flow occur at the contact surfaces of the first inner diameter portion 54 and the first outer diameter portion 61, and the second inner diameter portion 55 and the second outer diameter portion 62. When the foreign matter is removed and the energization is stopped in this state, the softened portion is solidified again, and the new metal surfaces are metallurgically bonded (diffusion bonding). Thus, the first joint P11 is formed between the first inner diameter portion 54 and the first outer diameter portion 61, and the second joint portion is disposed between the second inner diameter portion 55 and the second outer diameter portion 62. P12 is formed.

  By passing through the above processes, joining of the ring gear 50 and the differential case 60 is completed. Between the first joint P11 and the second joint P12 formed in this case, there is a gap 65 where the metals do not contact each other over a predetermined axial length. That is, the first and second inner diameter portions 54 and 55 of the ring gear 50 and the first and second outer portions of the differential case 60 so that the first joint portion P11 and the second joint portion P12 are separated from each other in the axial direction. The dimensional relationship between the diameter portions 61 and 62 (the axial size relationship) is set, and by setting such a dimensional relationship, a gap portion is formed between the joint portions P11 and P12 in a state after joining. 65 is formed.

  As described above, in the second embodiment of the present invention, when the ring gear 50 and the differential case 60 are joined, first, the first inner diameter portion 54 with the inner diameter X11 is formed on the inner peripheral wall portion of the ring gear 50, A second inner diameter portion 55 having a larger inner diameter X12 is formed, and the outer diameter of the outer peripheral wall portion of the differential case 60 is larger than the inner diameters X11 and X12 by the overlap margins S11 and S12 (the outer diameters Y11 and Y12). ) The first outer diameter portion 61 and the second outer diameter portion 62 are formed. Then, the first and second outer diameter portions 61 and 62 of the differential case 60 are brought into contact with the first and second inner diameter portions 54 and 55 of the ring gear 50 respectively, and the ring gear 50 and the differential case 60 are connected to each other. The first inner diameter portion 54 and the first outer diameter portion 61 are joined between the members 50 and 60 by energizing the pair of electrodes 71 and 72 while applying pressure in the axial direction. The joint portion P11 and the second joint portion P12 in which the second inner diameter portion 55 and the second outer diameter portion 62 are joined are formed, and the metals do not contact each other between the joint portions P11 and P12. The gap 65 is formed over a predetermined axial length. According to such a configuration, higher bonding strength can be obtained with less bonding energy for the same reason as described in the first embodiment.

  Further, in the second embodiment, as shown in FIG. 9, when the steel ring gear 50 and the cast iron differential case 60 are joined, the current values I1 and I2 due to the difference in the electric resistance values of the two are obtained. Due to the size, the overlap margin S12 of the upper contact portion C12 (the contact portion between the second outer diameter portion 62 and the second inner diameter portion 55), which is likely to become higher temperature when energized, is changed to the lower contact portion C11 (the first contact portion C11). The overlap margin S2 of the outer diameter portion 12 and the second inner diameter portion 5) is set to be larger. As described above, by setting an appropriate overlap margin according to the temperature rise width of the contact portion, the first and second outer diameter portions 61 and 62 and the first and second outer diameter portions 61 and 62 are set in the same manner as in the first embodiment. The quality of each joint part P11 and P12 with 2 inner diameter parts 54 and 55 can be ensured favorably, and the joint strength of the clutch cone 1 and the helical gear 10 can fully be raised.

  In the second embodiment, the ring gear 50 and the differential case 60 are joined through the two joint portions P11 and P12 that are spaced apart in the axial direction. However, FIGS. 6A and 6B described above. Similarly, the number of joints may not be two, and the ring gear 50 and the differential case 60 may be joined via three or more joints.

  In the second embodiment, the first and second outer diameter portions 61 and 62 are not located in the axial direction intermediate portion having the largest outer diameter in the differential case 60 but in the portion near the lower end having a smaller outer diameter. This is joined to the first and second inner diameter portions 54 and 55 of the ring gear 50, but it is naturally possible to join the ring gear 50 to the portion with the largest outer diameter of the differential case 60. It is. Below, joining of the differential case 160 and the ring gear 150 by such an aspect is demonstrated based on FIG. 11 and FIG.

  As shown in FIG. 11, a first outer diameter portion 161 having an outer diameter Y <b> 101 and an outer diameter Y <b> 102 larger than the outer diameter Y <b> 101 are formed on the outer peripheral wall portion of the axially intermediate portion having the largest outer diameter in the differential case 160. And a second outer diameter portion 162 having the shape. On the other hand, corresponding to the first and second outer diameter portions 161 and 162, the inner peripheral wall portion of the ring gear 150 (the peripheral wall of the opening 152) has a first inner diameter portion 154 having an inner diameter X101 and an inner diameter X101. And a second inner diameter portion 155 having a larger inner diameter X102. The outer diameter Y101 of the first outer diameter portion 161 is slightly larger than the inner diameter X101 of the first inner diameter portion 154, and the outer diameter Y102 of the second outer diameter portion 162 is slightly larger than the inner diameter X102 of the second inner diameter portion 155.

  When the ring gear 150 and the differential case 160 having such a configuration are joined by the same method as in the second embodiment, a joined structure as shown in FIG. 12 is obtained. As shown in the figure, the ring gear 150 and the differential case 160 include a first joint P101 formed between the first inner diameter portion 154 and the first outer diameter portion 161, the second inner diameter portion 155, and the second It joins via the 2nd junction part P102 formed between the outer diameter parts 162, and the clearance gap part 165 is formed between both the junction parts P101 and P102.

  In the example of FIGS. 11 and 12 as described above, since the diameters of the joint portions P101 and P102 are larger than those in the case of the second embodiment (FIGS. 7 to 10), the total joint area is large. It is expected that the bonding strength is further improved. However, if the bonding area is too large, the energy required for bonding becomes excessive, and it is considered difficult to maintain the quality of the bonding portions P101 and P102 with a certain degree of accuracy. Therefore, when the outer shape of the differential case 160 is large and the diameters of the joints P101 and P102 are considerably large, as shown in the second embodiment (FIGS. 7 to 10), the outer diameter of the differential case 60 is relatively large. It is desirable that first and second outer diameter portions 61 and 62 are formed in a small portion of the ring gear 50 and joined to the first and second inner diameter portions 54 and 55 of the ring gear 50.

1 Clutch cone (first metal member)
2 Opening portion 4 First inner diameter portion 5 Second inner diameter portion 10 Helical gear (second metal member)
11 First outer diameter portion 12 Second outer diameter portion 15 Gap portion 21 Upper electrode (electrode)
22 Lower electrode (electrode)
C1 Contact portion (the first outer diameter portion and the first inner diameter portion) Contact portion C2 Contact portion (the second outer diameter portion and the second inner diameter portion) P1 First joint portion P2 Second joint portion S1, S2 Overlap allowance

50 Ring gear (first metal member)
52 Opening 54 First Inner Diameter 55 Second Inner Diameter 60 Differential Case (Second Metal Member)
61 1st outer diameter part 62 2nd outer diameter part 65 Gap part 71 Upper electrode (electrode)
72 Lower electrode (electrode)
C11 Contact portion (the first outer diameter portion and the first inner diameter portion) Contact portion C12 Contact portion (the second outer diameter portion and the second inner diameter portion) P11 First joint portion P12 Second joint portion S11, S12 Overlap allowance I1, I2 current

Claims (5)

A first metal member provided with an opening and a second metal member having an outer peripheral wall that can partially contact the inner peripheral wall of the first metal member surrounding the opening are pressurized in the axial direction. While joining by resistance heating by energization,
Forming a first inner diameter portion having a predetermined inner diameter and a second inner diameter portion having an inner diameter larger than the first inner diameter wall portion of the first metal member;
Forming a first outer diameter portion and a second outer diameter portion having an outer diameter larger than the first inner diameter portion and the second inner diameter portion by a predetermined overlap margin on the outer peripheral wall portion of the second metal member;
Of the contact portion between the first outer diameter portion and the first inner diameter portion, and the contact portion between the second outer diameter portion and the second inner diameter portion, the overlap margin of the contact portion that becomes hotter when energized , Set larger than the overlap margin of the other contact part,
The first metal member and the second metal member are paired with the first and second inner diameter portions of the first metal member in contact with the first and second outer diameter portions of the second metal member, respectively. The first joint part in which the first inner diameter part and the first outer diameter part are joined between the two metal members by applying current while pressing in the axial direction using the electrode of the electrode, and the second inner diameter Forming a second joining portion in which the portion and the second outer diameter portion are joined, and forming a gap between the joining portions so that the metals do not contact each other over a predetermined axial length. A method for joining metal members. In the joining method of the metal member of Claim 1,
Of the contact portion between the first outer diameter portion and the first inner diameter portion, and the contact portion between the second outer diameter portion and the second inner diameter portion, the overlap margin of the contact portion having a shorter distance from the electrode Is set to be larger than the overlap margin of the other contact portion. In the joining method of the metal member of Claim 1,
The first metal member and the second metal member are made of different metals having different electric resistance values,
Of the contact portion between the first outer diameter portion and the first inner diameter portion, and the contact portion between the second outer diameter portion and the second inner diameter portion, an overlap margin of a contact portion having a larger current flowing during energization is set. The method of joining metal members, characterized in that the metal member is set to be larger than an overlap margin of the other contact portion. In the joining method of the metal member of any one of Claims 1-3,
The metal member joining method, wherein the first metal member is a clutch cone used in a manual transmission, and the second metal member is a gear joined to the clutch cone. In the joining method of the metal member of any one of Claims 1-3,
The metal member joining method, wherein the first metal member is a gear used for a differential mechanism, and the second metal member is a differential case joined to the gear.

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