Joining member, joining method and joined body

Abstract

The present invention provides a joining member, joining method, and joined body in which the removal force is increased by a sufficient retaining structure in joining members joined by press-fitting in an interference fit (fitting with interference). [Solution] The joining member 10 has a first metal member 11 and a second metal member 21, and is used for joining by press-fitting. The second metal member 21 is a member that is more easily deformed than the first metal member 11, and the first metal member 11 has a protrusion 15 on at least a part of the contact surface with the second metal member 21, and the protrusion 14 has a tapered surface that gradually expands the diameter of the first metal member 11 from the front to the rear in the press-fitting direction in a part of the region in the press-fitting direction of the first metal member 11.

Description

[Technical field]

[0001] The present invention relates to a joining member used for press-fit joining of metal members, a joining method, and a joined body. [Background technology]

[0002] Conventionally, when joining metal members together, there is a joining method by pressing one metal member into a hole provided in the other metal member. In addition, in order to firmly fit the metal members together, a technique is known in which serrations are formed on the circumferential surface of one member (e.g., a shaft member) and when the other member is pressed into a hole provided in the other member, a part of the serrations is deformed or a groove is carved into the inner circumferential surface of the hole by the serrations to fit the metal members together (see, for example, Patent Document 1). Known patterns of serrations include those formed along the axis of the shaft member or inclined relative to the axis (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3402036 [Patent Document 2] JP 2004-293714 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, particularly in the case of press-fitting in an interference fit (fitting with interference) where the member is fixed once fitted and will not be disassembled, there is a limit to the improvement in the pull-out load (improvement in removal force, improvement in difficulty in pulling out) in the case of a configuration having multiple protrusions aligned along the pressing direction (for example, the axial direction of a shaft member, etc.) or inclined relative to the pressing direction (for example, the axial direction) as in the conventional case.

[0005] Specifically, when one metal component has a high hardness and the other has a low hardness, or when a component is fitted into a housing of a specific shape, even if there is a tight fit, the dimensional difference between the metal components cannot be ensured to be large, and as a result, there is a problem that the removal force cannot be increased (resistance to high removal forces is low).

[0006] Furthermore, when one metal member has a high hardness and the other metal member has a low hardness, there is a risk that the metal member with the lower hardness will break, and so there is a limit to the load that can be applied by pressing them in. For this reason, for example, when joining stainless steel and aluminum, the stainless steel is generally hardened, and the two are pressed together and then laser welded to maintain a certain degree of joining strength, which makes the joining process complicated and limits the improvement of the joining strength and the removal force.

[0007] In view of the above circumstances, the present invention aims to provide a joined member, a joining method, and a joined product in which the joining members are joined by press-fitting in an interference fit (fitting with interference), and in which the removal force is increased by a sufficient anti-pullout structure (for example, by increasing the axial pullout load or rotational torque strength to make it difficult to come out). [Means for solving the problem]

[0008] The present invention relates to a joining member having a first metal member and a second metal member and used for joining by press-fitting, the second metal member being a member that is more easily deformed than the first metal member, the first metal member being provided with a protrusion on at least a part of a contact surface with the second metal member, the protrusion having a tapered surface that gradually increases the diameter of the first metal member from the front to the rear in the press-fitting direction in a partial region in the press-fitting direction of the first metal member. After the press-fitting, the first metal member and the second metal member are fitted together without being melted, with a part of the second metal member being elastically deformed, or with a part of the second metal member being elastically deformed and plastically deformed. The joining member is characterized by the above.

[0009] The present invention also relates to a joining member having a first metal member and a second metal member and used for joining by press-fitting, the second metal member being a member that is more easily deformed than the first metal member, the first metal member being provided with a plurality of protrusions on a contact surface with the second metal member that protrude radially outward of the first metal member, and each of the protrusions has an angle of 0.05 mm with respect to a press-fitting direction. 50 degrees and a sloped portion.

[0010] The present invention also provides a joining method using the joining member described above, comprising overlapping and pressing the first metal member and the second metal member together, Without melting the first metal member and the second metal member By the protrusion Applicable A part of the second metal member By elastically deforming a part of the second metal member, or by elastically deforming and plastically deforming a part of the second metal member, This joining method is characterized by deforming the two parts and fitting them together.

[0011] The present invention also relates to a bonded body bonded by the above-mentioned bonding method. Effect of the Invention

[0012] According to the present invention, it is possible to provide a joining member, a joining method, and a joined body in which the joining members are joined by pressing in an interference fit (fitting with interference) and have an adequate anti-pullout structure that increases resistance to pull-out forces (for example, by increasing the axial pull-out load or rotational torque strength to make them less likely to come out). [Brief description of the drawings]

[0013] [Figure 1] 1A and 1B are diagrams showing a joining member according to an embodiment of the present invention, in which (a) is a top view of a first metal member, (b) is a side view of the first metal member, (c) is a top view of a second metal member, and (d) is a side view of the second metal member 21. [Diagram 2] 1A and 1B are views showing a joining member according to an embodiment of the present invention, in which FIG. 1A is a top view of a first metal member, and FIG. 1B is a side view of the first metal member. [Diagram 3]1A to 1C are diagrams showing an example of a joining method using a joining member of the present embodiment, in which (a) is a side view, (b) is a side view, and (c) is a top view of (b). [Figure 4] 4 is a side view illustrating the first metal member of the present embodiment and a comparative example. FIG. [Diagram 5] 1 is a conceptual diagram illustrating a bonded body according to the present embodiment and a comparative example. [Figure 6] 5(b) is an enlarged conceptual diagram of the vicinity of the protrusion in FIG. 5(b). [Figure 7] 10 is a side view showing another example of the protrusion of the present embodiment. FIG. [Figure 8] FIG. 13 illustrates another embodiment of the present invention. [Figure 9] FIG. 13 illustrates another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0015] 1 and 2 are diagrams showing a joining member 10 of this embodiment, with Fig. 1(a) and Fig. 2(a) being top views of a first metal member 11, Fig. 1(b) and Fig. 2(b) being side views of the first metal member 11, Fig. 1(c) being a top view of a second metal member 21, and Fig. 1(d) being a side view of the second metal member 21. Note that in the following diagrams, for ease of explanation, main components are shown exaggerated.

[0016] The joining member 10 is composed of a first metal member 11 and a second metal member 21 joined by press-fitting in an interference fit state (fitting with interference).

[0017] The first metal member 11 and the second metal member 21 are different kinds of metal members, and the second metal member 21 is a member that is more easily deformed than the first metal member 11. Here, "easily deformed" means, for example, that it is easy to deform at least by elastic deformation, or that it is easy to deform (in addition to elastic deformation) by plastic deformation or by engraving (cutting) of a groove. As an example, the hardness of the second metal member 21 is lower than that of the first metal member 11, and specifically, the first metal member 11 is stainless steel, and the second metal member 21 is aluminum. Also, here, as an example, a case where the first metal member 11 is press-fitted into the hole portion 24 of the second metal member 21 will be described.

[0018] 1(a) and 1(b), the first metal member 11 has, for example, pressing surfaces 12A and 12B and a side surface 13, and is a substantially cylindrical (ring-shaped) shape having a hole 14, the pressing surfaces 12A and 12B are surfaces that directly receive a pressing force, and the side surface (circumferential surface) 13 is a contact surface with the second metal member 21. The peripheral surface (in this example, the outer peripheral surface) 13 is provided with a plurality of linear protrusions 15 (three in this example) that protrude toward the second metal member 21 when pressed in. Here, for the sake of convenience, in the following explanation of the directions, the direction perpendicular to the pressing surfaces 12A and 12B (the plate thickness direction of the first metal member 11) is referred to as the (cylinder) axial direction V, the direction horizontal to the pressing surfaces 12A and 12B is referred to as the radial direction H, and the direction along the peripheral surface (outer peripheral surface) 13 is referred to as the circumferential direction R.

[0019] In top view as shown in Figure 1(a), the protrusion 15 has a tip portion 15T that protrudes at an acute angle from the axial center of the cylinder toward the outside in the radial direction H, and in a plan view of the outer circumferential surface 13 (side view as shown in Figure 1(b)), the tip portion 15T is formed in a line extending in a direction different from the axial direction V.

[0020] More specifically, the protrusion 15 extends from the pressing surface (upper surface) 12A to reach the pressing surface (lower surface) 12B, but is inclined with respect to the axial direction V so that the position (e.g., the starting point) P1 of the tip 15T on the pressing surface 12A and the position (e.g., the end point) P2 of the tip 15T on the pressing surface 12B are offset in the circumferential direction R, and is formed in a curved (arcuate) shape that is curved in one direction when viewed in a plane of the outer circumferential surface 13 (curved so as to be convex toward the right in the radial direction H in the same figure (b)).

[0021] As shown in FIG. 1(a), the protrusions 15 are provided at, for example, three locations spaced apart at substantially equal intervals. Note that FIG. 1(b) is a schematic diagram for the convenience of explaining adjacent protrusions 15, and does not correspond to the positions of the protrusions 15 shown in FIG. 1(a). Furthermore, adjacent protrusions 15 are spaced apart so as not to overlap at all in the axial direction V (or circumferential direction R). In detail, the protrusions 15 are formed in an arc shape in which the position of the start point P1 and the position of the end point P2 are offset in the circumferential direction R, and each protrusion 15 exists over a predetermined range of an arrangement region DR in the circumferential direction R. The protrusions 15 are spaced apart so that no other protrusions 15 exist in the arrangement region DR of each protrusion 15.

[0022] As shown in Figures (c) and (d), the second metal member 21 has, for example, pressing surfaces 22A, 22B and a side surface 23, and is an (approximately) cylindrical (ring-shaped) shape with a hole 24 in the center, and the pressing surfaces 22A, 22B are the surfaces that directly receive the pressing force, and the inner peripheral surface 25 of the side surface 23 (the peripheral surface, inner peripheral surface of the hole 24) is the contact surface with the first metal member 11.

[0023] 2, the protrusion amount D of the protrusion 15 of the first metal member 11 (the distance from the outer circumferential surface 13 to the tip 15T) is, for example, about 0.1% to 0.5% of the size (outer diameter d1) of the pressing surface 15A (15B).

[0024] As mentioned above, the protrusions 15 are exaggerated in the drawings for the sake of convenience, but in reality, the ratio of the protrusions 15 to the size (diameter) of the first metal member 11 is different from that shown in the drawings, and the protrusions 15 are very fine compared to the size (diameter) of the first metal member 11.

[0025] For example, when the outer diameter d1 of the pressing surface 15A is about 25 mm, the protrusion amount D is about 50 μm. The protrusion 15 is arc-shaped with a curvature larger than 0 but relatively small, and the inclination angle with respect to the axial direction V is, for example, about 50 degrees as the angle α of the tangent of the arc at the center position in the axial direction V (plate thickness direction).

[0026] The interference between the first metal member 11 and the second metal member 21 is, for example, about 15 μm to 30 μm in terms of diameter (outer diameter d1 of the first metal member 11-inner diameter (diameter of hole 24) d3 of the second metal member 21).

[0027] FIG. 3 is a diagram showing an example of a joining method using the joining member 10 of this embodiment, in which (a) and (b) are side views, and (c) is a top view of (b).

[0028] In the joining method of this embodiment, first, the second metal member 21 is placed on a die 41 of an insertion machine or a press machine, the first metal member 11 is placed (stacked) on top of it, and the pressing surface (e.g., pressing surface 12A) of the first metal member 11 is pressed by a punch 42 (Figure 3(a)).

[0029] At this time, the first metal member 11 is pressed into the hole 24 of the second metal member 21 while rotating in a spiral along the arc-shaped protrusion 15. Here, since the second metal member 21 is more easily deformed than the first metal member 11, the second metal member 21 at least undergoes elastic deformation, or in addition to elastic deformation, undergoes plastic deformation, and the protrusion 15 deforms so as to scrape off a part of the inner peripheral surface 25 of the second metal member 21 (so as to carve a groove), so that the protrusion 15 and the inner peripheral surface 25 of the second metal member 21 are firmly fitted (fitted). In this way, the first metal member 11 and the second metal member 21 are joined by press-fitting in an interference fit state, and a joined body 30 is formed in which the outer peripheral surface 13 of the first metal member 11 contacts the inner peripheral surface 25 of the hole 24 of the second metal member 21 (FIGS. 1(b) and 1(c)).

[0030] Note that the number of protrusions 15 and the size of each of the above-mentioned components, including the protrusion amount D, are merely examples, and are selected appropriately depending on the material, plate thickness, diameter, and required joining strength and removal force of the first metal component 11 and the second metal component 12.

[0031] Furthermore, the number of protrusions 15 may be more than one, but considering the stability when the first metal member 11 is placed on the second metal member 21 and pressed, three or more is preferable.

[0032] In this manner, in this embodiment, arc-shaped protrusions 15 spaced apart so as not to overlap each other in the circumferential direction R (and axial direction V) are formed on the peripheral surface (outer peripheral surface) 13 of the first metal member 11, which is less likely to deform, and the first metal member 11 is press-fitted into the hole 24 of the second metal member 21, which is more likely to deform, by interference fit, to form the joined body 30. This enables the joined body 30 to significantly increase not only the joining strength but also the pull-out load (removal force).

[0033] This will be described below with reference to Figures 4 to 6. First, according to this embodiment, it is believed that the number and arrangement of the projections 15 can increase the removal force.

[0034] FIG. 4 is a side view showing the first metal member 11 of this embodiment and a comparative example. FIG. 4(a) and FIG. 4(b) are examples of first metal members 50, 52 that are comparative examples of the first metal member 11, and FIG. 4(a) is a side view of the first metal member 50 on which a plurality of linear protrusions (protrusions) 51 are formed along the axial direction V. FIG. 4(b) is a side view of the first metal member 52 on which a plurality of linear protrusions (protrusions) 53 inclined with respect to the axial direction V are formed, and adjacent protrusions 53 are arranged so as to overlap each other partially in the circumferential direction R (axial direction V). For example, in this example, one protrusion 53 (53A) is entirely positioned over the arrangement region DR, but other protrusions 53 (53B, 53C) adjacent to each other on the left and right are arranged in the arrangement region DR so as to overlap one protrusion 53A partially in the circumferential direction R (axial direction V).

[0035] 4(c) is a side view of the first metal member 11 on which the protrusion 15 of this embodiment is formed. The first metal members 50, 52, and 11 shown in Fig. 4 all have the same configuration except for the protrusions, and the second metal member 21 into which the first metal members 50, 52, and 11 are press-fitted has the same configuration as that shown in Fig. 1(c) and Fig. 1(d).

[0036] Fig. 5 is a conceptual diagram showing the bonded body 30 of this embodiment and a comparative example. Fig. 5(a) is a conceptual diagram of the top surface of a bonded body 60 formed by press-fitting the first metal member 52 shown in Fig. 4(b) into the second metal member 54, and Fig. 5(b) is a conceptual diagram of the top surface of the bonded body 30 of this embodiment. The first metal member 50 shown in Fig. 4(a) is similar to Fig. 5(a).

[0037] 6 is a conceptual diagram enlarging the vicinity of the protrusion 15 in FIG. 5(b). As described above, the protrusion 15 is shown in an exaggerated manner in each diagram of this embodiment, and the actual shape is close to that shown in FIG. 6 (to repeat, the ratio of the curvature of the actual protrusion 15 to the outer diameter of the first metal member 11 is different from that shown in FIG. 6). FIG. 6 is a schematic diagram of a top view enlarging the vicinity of the protrusion 15 in FIG. 5, but the formation positions of the protrusions 15 along the axial direction V (plate thickness direction) are shown shifted sequentially.

[0038] In the joining by press fitting in this embodiment, the second metal members 21, 54 are more easily deformed than the first metal members 11, 53, and more specifically, have a lower hardness, for example. In other words, it is considered that the second metal members 21, 54 are at least elastically deformed by press fitting to come into close contact with the first metal members 11, 53, and in addition, a portion of the second metal members may be plastically deformed, thereby fitting the two together.

[0039] In this case, focusing particularly on elastic deformation, in the comparative example, as shown in Fig. 5(a), when the first metal member 52 (50) is pressed in, the tips of the protrusions 53 (51) come into point (line) contact with the second metal member 54 and press the second metal member 54 outward in the radial direction H as indicated by the single arrow. Also, the areas between the protrusions 53 press the second metal member 54 in the circumferential direction R as indicated by the double arrow so as to expand it. In this way, when there are a large number of protrusions 53, there is a lot of point (line) contact at the tips and, conversely, the surface contact between the protrusions 53 is small.

[0040] And, since the large number of protrusions 53 press the entirety outward in the radial direction H as shown by the single arrow, the amount of elastic deformation (distributed amount of elastic deformation) near each protrusion 53 becomes small as shown by the broken line, making it difficult for each to deform flexibly. Also, even in the region between the protrusions 53, the area in actual surface contact becomes even smaller, which is thought to reduce adhesion.

[0041] Furthermore, particularly as shown in Figure 4(b), when adjacent protrusions 53B, 53C are arranged so as to overlap each other along the circumferential direction R (axial direction V) in the arrangement region DR of a certain protrusion 53A, part of the area of ​​surface contact between the protrusions 53 also becomes point (line) contact at the tips of the protrusions 53, further reducing the area of ​​surface contact.

[0042] In contrast, in this embodiment, as shown in Figures 5(b) and 6, the point (line) contact at the tip 15T of the protrusion 15 is much less than that in Figure 5(a), and conversely, the surface contact between the protrusions 15 is much greater. In addition, the number of protrusions 15 is small, and the overall amount of pressure applied outward in the radial direction H is small, so that the amount of elastic deformation (distributed amount of elastic deformation) near each protrusion 15 can be sufficiently ensured. In other words, as shown by the dashed lines, it can be said that each of them can undergo gentle and flexible deformation (for example, deformation in which the protrusions expand and contract toward the protrusions 15 near the protrusions 15, and deformation in which the contact surfaces of the first metal member 11 and the second metal member 21 come into close contact with each other between the protrusions 15).

[0043] Furthermore, as shown in particular in Figure 1(b), in the arrangement region DR of a certain protrusion 15, adjacent protrusions 15 do not overlap along the circumferential direction R (axial direction V), so that an area of ​​surface contact between the protrusions 15 can be sufficiently secured.

[0044] 5(a), the second metal member 21 in this embodiment is configured to elastically deform gently near each protrusion 15 while suppressing the overall deformation amount, and to ensure a sufficient area for surface contact. This is believed to increase the adhesion between the first metal member 11 and the second metal member 21, and to be able to withstand a high removal force.

[0045] 4(a), in the case of the first metal member 50 shown in FIG. 4(a), the second metal member 54 is elastically deformed by the press-fitting, and is in close contact with the first metal member 50 along the protrusion 51 as shown by hatching, but the extension direction of the protrusion 51 coincides with the axial direction V, and the progress of the first metal member 50 in the axial direction V (shown by the arrow) is not restricted in any way. Therefore, for example, if a force exceeding the bonding strength is applied in the axial direction V (the pushing direction during press-fitting or the opposite direction) on the assumption that the second metal member 54 will not break, the first metal member 50 will be pulled out of the second metal member 54.

[0046] The same is true for the first metal member 52 shown in Fig. 1(b), where the second metal member 54 is elastically deformed by the press-fitting and comes into close contact with the first metal member 52 along the protrusion 51 as shown by hatching, but there is no restriction on the progress of the first metal member 52 in the extending direction of the protrusion 53 (indicated by the arrow). Therefore, for example, assuming that the second metal member 54 is not broken, if a force exceeding the bonding strength is applied in the extending direction of the protrusion 53 (the pushing direction during press-fitting or the opposite direction), the first metal member 52 will be pulled out of the second metal member 54.

[0047] In contrast, as shown in Fig. 6(c) and Fig. 6, the protrusion 15 in this embodiment is formed in an arc shape in a plan view (side view) of the outer circumferential surface 13 of the first metal member 11. The second metal member 21 is elastically deformed by press-fitting, and is in close contact with the first metal member 11 along the protrusion 15 as shown by hatching.

[0048] In this case, even if the first metal member 11 is moved in the axial direction V or in a direction inclined relative to the axial direction V (the pushing direction during press-fitting or the opposite direction) as shown by the arrow in order to remove the first metal member 11 from the second metal member 21, its progress will be restricted by one of the portions PX of the arc-shaped protrusion 15 abutting against the second metal member 21.

[0049] In other words, the protrusion 15 formed on the first metal member 11 in this embodiment includes a regulating portion PX that regulates the first metal member 11, engaged with the second metal member 21, from progressing linearly in the pressing direction (axial direction V) and in a direction inclined relative to the pressing direction.

[0050] Therefore, even when attempting to remove the first metal member 11 from the second metal member 21, the progress of the first metal member 11 is restricted by the restricting portion PX, so that the force for removing the first metal member 11 from the second metal member 21 can be significantly improved compared to the conventional art.

[0051] Although FIG. 1(c) shows only a few regulating portions PX, if the protrusion 15 is formed in an arc shape, the entire protrusion 15 becomes a regulating portion PX that regulates linear progress in the pressing direction (axial direction V) and in a direction inclined relative to the pressing direction (at least one of the inclined directions).

[0052] Specifically, for example, assuming that all conditions other than the shapes of the protrusions 15, 51, and 53 are the same, if the removal force (removal load) when the protrusions 51 and 53 shown in Figures 11(a) and 11(b) are formed is, for example, 20 kg to 30 kg, this can be improved to 200 kg to 300 kg by using the pattern of the protrusion 15 of this embodiment.

[0053] Note that while the elastic deformation of the second metal member 21 (54) has been mainly described here, the second metal member 21 may also engage (fit) with the first metal member 11 through partial plastic deformation and / or the carving of grooves along the protrusion 15 in addition to elastic deformation.

[0054] FIG. 7 is a side view showing another example of the protrusion 15. As shown in FIG.

[0055] The protrusion 15 is not limited to the above example, so long as it includes a control portion PX that controls the first metal member 11, which is engaged with the second metal member 21, from progressing linearly in the pressing direction (axial direction V) and in a direction inclined relative to the pressing direction.

[0056] For example, as shown in Fig. 1(a), protrusions 15 may be formed from the upper and lower pressing surfaces 12A and 12B toward the center of the plate thickness and inclined with respect to the axial direction V. In this case, protrusion 15A from one pressing surface 12A toward the center of the plate thickness and protrusion 15B from the other pressing surface 12B toward the center of the plate thickness are formed at positions shifted parallel to the axial direction V so as not to be in each other's extending direction. As a result, the end portions of both protrusions 15A and 15B on the center side of the plate thickness become the restriction portions PX.

[0057] In this case, although they overlap in the circumferential direction, the length of the projections 15A, 15B is short, so that a sufficient area for surface contact can be ensured.

[0058] Also, as shown in Fig. 1B, the protrusion 15 may be arc-shaped, but may be formed so that one of its extending ends (e.g., end point P2) does not reach the pressing surface (e.g., pressing surface 12B). In the case of an arc-shaped protrusion, the restricting portion PX exists over the entire protrusion, but with this shape, when the second metal member 21 is scraped off by the press-fitting, the scraps can be prevented from being discharged to the outside.

[0059] 8 shows an example in which the first metal member 11 and the second metal member 21 are interchanged. Fig. 8(a) is a top view of the second metal member 21, Fig. 8(b) is a top view of the first metal member 11, Fig. 8(c) is a top view of a joined body 30 formed by pressing the two together, and Fig. 8(d) is a side view of the joined body 30.

[0060] As shown in FIG. 8, a hole 17 may be formed in a first metal member 11 which is less likely to deform, and a second metal member 21 which is more likely to deform may be press-fitted into the hole 17.

[0061] In this case, protrusions 15 that protrude toward the second metal member 21 (inside) are formed on the peripheral surface (inner peripheral surface) 18 of the hole 17 of the first metal member 11, which is the contact surface with the second metal member 21. The pattern of the protrusions 15 in a side view is the same as that shown in Figs. 1 and 5.

[0062] Even in this case, the protrusions 15 have a regulating portion PX that regulates the protrusions 15 from progressing linearly in the pressing direction (axial direction V) and in a direction inclined relative to the pressing direction, and since the number of protrusions 15 is small and large surface contact can be ensured, the adhesion with the second metal member 21 can be increased and the protrusions 15 can withstand a high removal force.

[0063] 9 is a side view showing another embodiment of the first metal member 11. The first metal member 11 is not limited to the above example as long as it has a protrusion 15 protruding toward the second metal member 21 on the contact surface with the second metal member 21 and the protrusion 15 causes at least a part of the second metal member 21 to elastically deform.

[0064] For example, as shown in FIG. 9(a), a single protrusion 15 may be provided on the outer peripheral surface of the first metal member 11. The protrusion 15 is provided in a ring shape that is continuous in the circumferential direction R along the outer peripheral surface of the first metal member 11. More specifically, the protrusion 15 may be formed so that it protrudes in the radial direction H from a base point S1 of one of the protrusions (upper side in the axial direction V in the figure) toward the tip portion 15T so as to be at substantially the same position in the axial direction V (the tip portion 15T protrudes (almost) horizontally in the radial direction H from the base point S1 of one protrusion), and the base point S2 of the other protrusion is located at the end of the axial direction V of the first metal member 11 (lower end in the figure), and may be formed into a wedge shape that exhibits a gentle taper shape from the tip portion 15T to the starting point S2 (tip in the press-fitting direction). In this case, for example, the radial positions of the base points S1 and S2 are (almost) the same position as shown by the dashed line.

[0065] In the case of a first metal member 11 having a wedge-shaped protrusion 15 as shown in Fig. 1(a), as shown in Fig. 1(b) to Fig. 1(d), it is preferable to make the plate thickness (thickness in the axial direction V) of the first metal member 11 (Fig. 1(b) and Fig. 1(d)) smaller than the plate thickness of the second metal member 21 (Fig. 1(c) and Fig. 1(d)) and provide a support portion 27 for supporting the first metal member 11 on the inner peripheral surface 25 of the hole portion 24 of the second metal member 21, so as to more preferably prevent the first metal member 11 from coming off in the axial direction H. The support portion 27 protrudes inward (toward the axial center) from the inner peripheral surface 25 of the second metal member 21 so as to be able to support the bottom of the first metal member 11 (Fig. 1(d)).

[0066] In the case of the wedge-shaped protrusion 15 shown in Fig. 1(a) to (d), the diameter becomes smaller toward the tip in the press-fitting direction (the lower part in the figure), and the protrusion 15 (tip part 15T) has a gentle taper from the tip in the press-fitting direction, making it easier to press-fit and reducing the press-fitting force. Also, because the protrusion 15 is wedge-shaped, the removal load (removal force) in the press-fitting direction can be increased.

[0067] FIG. 1(e) shows a wedge-shaped projection 15 shown in FIG. 1(a) such that the base point S2 on the other side of the projection is positioned midway in the axial direction of the first metal member 11.

[0068] Even in this case, the diameter of the projection 15 becomes smaller toward the tip in the press-fitting direction (the lower part in the figure), and the projection 15 (tip 15T) is tapered from the tip in the press-fitting direction, making it easier to press in (reducing the press-fitting force). Moreover, since the projections 15 are all wedge-shaped, the removal load (removal force) in the press-fitting direction can be increased.

[0069] Furthermore, as shown in FIG. 2(f), the wedge-shaped protrusion 15 shown in FIG. 2(a) is not limited to being annular (a shape continuous in the circumferential direction R), but may be provided in a plurality of parts separated in the circumferential direction R.

[0070] In the case of a wedge-shaped protrusion 15 as shown in Fig. 1(f), the diameter becomes smaller toward the tip in the press-fitting direction (the lower part in the figure), and the portion from the tip in the press-fitting direction to the protrusion 15 (tip portion 15T) is gently tapered, making it easier to press in and reducing the press-in force. Also, because the protrusion 15 is wedge-shaped, the removal load (removal force) in the press-fitting direction can be increased.

[0071] In addition, the end portion of each protrusion 15 in the circumferential direction R serves as a restricting portion PX that restricts the rotation of the first metal member 11 in the circumferential direction R around the axis, thereby preventing the first metal member 11 from rotating out.

[0072] Also, as shown in Fig. 1(g), the protrusion 15 may be configured to protrude in the radial direction H so that its tip 15T is at a position different from both of the protrusion base points S1 and S2 in the axial direction V. In this case, the protrusion 15 may be continuous in the circumferential direction R as shown in Fig. 1(g), or may be provided in a plurality of portions separated in the circumferential direction R, although this is not shown.

[0073] In this case, the distances from the tip 15T of the projection 15 to the base points S1 and S2 in the axial direction V are approximately equal, but either one of the distances may be longer.

[0074] In this case, the tip portion 15T may be configured so that its position does not change in the axial direction V (see FIG. 1(g)), or it may be configured so that its position changes in the axial direction V (the tip portion 15T is inclined in side view).

[0075] Also, as shown in FIG. 1(h), the protrusions 15 shown in FIG. 1(a) (or shown in FIG. 1(g)) may be combined in a plurality of shapes in the axial direction of the first metal member 11.

[0076] As described above, in the embodiment shown in Figure 9, when the first metal member 11 is pressed into the second metal member 21, the second metal member 21 at least elastically deforms, or in addition to elastically deforming, plastically deforms, and deforms in such a way that a portion of the inner surface 25 of the second metal member 21 is scraped away (a groove is carved) by the protrusion 15, so that the protrusion 15 and the inner surface 25 of the second metal member 21 are firmly fitted (engaged), and a joint 30 is formed in which the outer surface 13 of the first metal member 11 is in contact with the inner surface 25 of the hole portion 24 of the second metal member 21 (see Figure 9 (d)).

[0077] According to the configuration of the above embodiment, even if the plate thickness of the first metal member 11 and the second metal member 12 is the same as that of the conventional one and the pressing force (press-in load) is the same as that of the conventional one, the removal load (removal force) can be significantly increased compared to the conventional one.

[0078] In other words, if it is sufficient to maintain the same level of removal load (removal force) as before, the plate thicknesses of the first metal member 11 and the second metal member 12 can be significantly reduced compared to before, which can contribute to making the parts smaller (lighter).

[0079] Furthermore, by making parts smaller and lighter, costs can be reduced and layout freedom is improved.

[0080] Furthermore, while an adhesive has been used in some cases to improve the removal force in the past, the removal force can be improved without using an adhesive.

[0081] In addition, the pressing machine can be made smaller (labor saving).

[0082] The joining member and joining method of this embodiment can be applied, for example, by forming the first metal member 11 into a ring shape and pressing the ring-shaped first metal member 11 into a part (e.g., an engine head, a die-cast part, a bearing part, or other pressed-in part) made of the second metal member 21 as reinforcement in a portion where strength is required. EXAMPLES

[0083] A bonded body 30 was formed using the bonding member 10 shown in FIG. 9(a), and the press-in force and removal force were compared with those of a comparative bonded body not provided with the projections 15.

[0084] In the joined body 30 of this embodiment, the first metal member 11 is made of carbon tool steel and has a plate thickness of 5.7 mm, and the second metal member 21 is made of aluminum.

[0085] The joint of the comparative example is not provided with protrusions 15, the material of the inner metal member (the member corresponding to the first metal member of this embodiment) is an iron-based sintered metal, and the material of the outer metal member (the member corresponding to the second metal member 21 of this embodiment) is aluminum similar to this embodiment. In addition, other configurations (plate thickness, outer diameter, inner diameter, interference, and other shapes) are the same for both.

[0086] The press-in load (press-in force) and the pull-out load (pull-out force, pull-out strength) were measured for the joined body 30 of this example and the joined body 60 of the comparative example. The joined body of the comparative example had a press-in load of 190 kgf and a pull-out strength of 190 kgf. On the other hand, the joined body 30 of this embodiment had a press-in load of 200 kgf and a pull-out strength of 520 kgf.

[0087] From these results, it became clear that according to the present invention, even if the plate thickness of the first metal member 11 and the second metal member 12 is made the same as in the conventional case and the pressing force (press-in load) is made the same as in the conventional case, the removal load (removal force) can be significantly increased compared to the conventional case.

[0088] In other words, if it is sufficient to maintain the same level of removal load (removal force) as before, the plate thickness of the first metal member 11 and the second metal member 12 can be significantly reduced compared to before, which can contribute to making the parts smaller (lighter). [Industrial Applicability]

[0089] The present invention can be used to join a plurality of members. [Explanation of symbols]

[0090] 10 Joining materials 11 First metal member 15 Protrusions 21 Second metal member 30 zygote

Claims

1. A joining member having a first metal member and a second metal member and used for joining by press fitting, the second metal member is a member that is more easily deformed than the first metal member, the first metal member has a protrusion on at least a part of a contact surface with the second metal member; the protrusion has a tapered surface in a partial region in a press-fitting direction of the first metal member, the tapered surface gradually increasing a diameter of the first metal member from the front to the rear in the press-fitting direction, After the press-fitting, the first metal member and the second metal member are fitted together without being melted, with a part of the second metal member being elastically deformed, or with a part of the second metal member being elastically deformed and plastically deformed. A joining member characterized by:

2. The protrusion has a wedge-shaped cross-sectional shape along the diameter of the first metal member. The joining member according to claim 1 .

3. The protrusion is provided in a continuous annular shape in a circumferential direction of the first metal member. The joining member according to claim 1 or 2.

4. The protrusion is provided in a plurality of portions in the press-fitting direction of the first metal member. The joining member according to claim 3 .

5. The protrusion is provided in a plurality of parts in a circumferential direction of the first metal member. The joining member according to claim 1 or 2.

6. A joining member having a first metal member and a second metal member and used for joining by press fitting, the second metal member is a member that is more easily deformed than the first metal member, The first metal member has a contact surface with the second metal member, and a plurality of protrusions are provided on the contact surface with the second metal member, the protrusions protruding radially outward from the first metal member. Each of the projections includes an inclined portion that forms an angle of 50 degrees with the press-fitting direction. A joining member characterized by:

7. A joined body joined by the joining member according to any one of claims 1 to 6.

8. A joining method using the joining member according to any one of claims 1 to 6, the first metal member and the second metal member are overlapped and pressed together, and the first metal member and the second metal member are fitted together by elastically deforming a part of the second metal member or by elastically and plastically deforming a part of the second metal member with the protrusion without melting the first metal member and the second metal member; A bonding method comprising the steps of:

9. A bonded body bonded by the bonding method according to claim 8.

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