JP7617639B2 - Joining member, joining method and joined body - Google Patents

Description

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

Conventionally, when joining metal members, there is a method of joining by pressing one metal member into a hole in the other metal member. In addition, in order to firmly fit metal members together, a technique is known in which serrations are formed on the circumferential surface of one member (e.g., shaft member) and when the other member is pressed into a hole in the other member, part of the serrations is deformed or a groove is carved into the inner circumferential surface of the hole by the serrations to allow the fitting (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).

Patent No. 3402036 JP 2004-293714 A

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

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 an interference 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).

In addition, if one metal component has a high hardness and the other has a low hardness, there is a risk that the metal component with the lower hardness will break, so there is a limit to the load that can be applied when pressing the components together. For this reason, when joining stainless steel and aluminum, for example, a certain degree of joining strength is generally maintained by hardening the stainless steel, pressing the two together, and then laser welding, which makes the joining process complicated and limits the improvement of joining strength and removal force.

In view of the above circumstances, the present invention aims to provide a joining member, joining method, and joined body that are joined by press-fitting in an interference fit (fitting with interference), and that have a sufficient anti-pullout structure to increase the removal force (for example, by increasing the axial pullout load or rotational torque strength to make it difficult to pull out).

The present invention relates to a joining member having a first metal member and a second metal member, which is used for joining by press-fitting, wherein 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, and the protrusion has a tapered surface in a part of the press-fitting direction of the first metal member that gradually expands the diameter of the first metal member from the front to the rear in the press-fitting direction, and after press-fitting, the first metal member and the second metal member are engaged with each other without melting, with a part of the second metal member elastically deformed, or with a part of the second metal member elastically deformed and plastically deformed .

The present invention also provides a joining member having a first metal member and a second metal member and used for joining by press-fitting, wherein the second metal member is a member that is more easily deformed than the first metal member, and the first metal member has a contact surface with the second metal member that is provided with a plurality of protrusions that protrude radially outward from the first metal member, and each of the protrusions includes an inclined portion that forms an angle of 50 degrees with the press-fitting direction.

The present invention also relates to a joining method using the above-mentioned joining member, characterized in that 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 portion of the second metal member with the protrusion without melting the first metal member and the second metal member, or by elastically deforming and plastically deforming a portion of the second metal member.

The present invention also relates to a bonded body bonded by the above-mentioned bonding method.

The present invention provides a joining member, joining method, and joined body that are joined by press-fitting in an interference fit (fitting with interference), and that have an adequate anti-pullout structure that increases resistance to removal forces (for example, by increasing the axial pullout load and rotational torque strength to make them less likely to come out).

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 a second metal member 21. 1A and 1B are diagrams 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. 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). 4 is a side view illustrating the first metal member of the present embodiment and a comparative example. FIG. 1 is a conceptual diagram illustrating a bonded body according to the present embodiment and a comparative example. 5(b) is an enlarged conceptual diagram of the vicinity of the protrusion in FIG. 5(b). 10 is a side view showing another example of the protrusion of the present embodiment. FIG. FIG. 13 illustrates another embodiment of the present invention. FIG. 13 illustrates another embodiment of the present invention.

The following describes an embodiment of the present invention with reference to the drawings.

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

The joining member 10 is composed of a first metal member 11 and a second metal member 21 that are joined by press-fitting in an interference fit state.

The first metal member 11 and the second metal member 21 are different types 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) 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, 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 here.

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 with a hole 14. The pressing surfaces 12A and 12B are the surfaces that directly receive the pressing force, and the side surface (circumferential surface) 13 is the contact surface with the second metal member 21. The peripheral surface (in this example, the outer peripheral surface) 13 has 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 axial direction V (of the cylinder), 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.

In top view as shown in FIG. 1(a), the protrusion 15 has a tip 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 FIG. 1(b)), the tip 15T is formed in a line extending in a direction different from the axial direction V.

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 position of the starting point) P1 of the tip 15T on the pressing surface 12A and the position (e.g., the position of 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 in a plan view 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)).

As shown in FIG. 1(a), the protrusions 15 are provided at three locations, spaced apart at (approximately) equal intervals. Note that FIG. 1(b) is a schematic diagram for convenience in 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 starting 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 the 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 one protrusion 15.

As shown in Fig. 1(c) and Fig. 1(d), the second metal member 21 has, for example, pressing surfaces 22A, 22B and a side surface 23, and is (approximately) cylindrical (ring-shaped) 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.

Referring to FIG. 2, the protrusion amount D of the protrusion 15 of the first metal member 11 (the distance from the outer peripheral surface 13 to the tip 15T) is, for example, approximately 0.1% to 0.5% of the size (outer diameter d1) of the pressing surface 15A (15B).

As mentioned above, the protrusions 15 are exaggerated in the drawings for ease of explanation, 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.

As an example, when the outer diameter d1 of the pressing surface 15A is, for example, about 25 mm, the protrusion amount D is about 50 μm. Furthermore, 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 of the axial direction V (plate thickness direction).

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 dimension (outer diameter d1 of the first metal member 11 - inner diameter (diameter of the hole portion 24) d3 of the second metal member 21).

Figure 3 shows an example of a joining method using the joining member 10 of this embodiment, where (a) and (b) are side views, and (c) is a top view of (b).

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

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 that a part of the inner peripheral surface 25 of the second metal member 21 is scraped off (so that a groove is carved) by the protrusion 15, and 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 joint 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. (b) and (c)).

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.

The number of protrusions 15 may be more than one, but considering the stability when placing and pressing the first metal member 11 on the second metal member 21, three or more is preferable.

In this manner, in this embodiment, arc-shaped protrusions 15 are formed on the peripheral surface (outer peripheral surface) 13 of the first metal member 11, which is less likely to deform, so as to be spaced apart so as not to overlap each other in the circumferential direction R (and axial direction V), 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, to form the joint 30. This allows the joint 30 to significantly increase not only the joining strength but also the pull-out load (removal force).

This will be explained below with reference to Figures 4 to 6. First, according to this embodiment, it is believed that the removal force can be increased by adjusting the number and arrangement of the protrusions 15.

Figure 4 is a side view showing the first metal member 11 of this embodiment and a comparative example. Figures 4(a) and 4(b) are examples of first metal members 50 and 52 that are comparative examples of the first metal member 11, and Figure 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. Figure 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 partially in the circumferential direction R (axial direction V). For example, in this example, one protrusion 53 (53A) is located in its entirety over the arrangement region DR, but in the arrangement region DR, other protrusions 53 (53B, 53C) adjacent to the left and right are arranged so as to overlap one protrusion 53A in the circumferential direction R (axial direction V).

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

Figure 5 is a conceptual diagram showing the joined body 30 of this embodiment and a comparative example. Figure 5(a) is a conceptual diagram of the top surface of the joined body 60 formed by pressing the first metal member 52 shown in Figure 4(b) into the second metal member 54, and Figure 5(b) is a conceptual diagram of the top surface of the joined body 30 of this embodiment. The first metal member 50 shown in Figure 4(a) is similar to Figure 5(a).

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

In the present embodiment, the joining by press fitting is performed such that 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, the press fitting causes the second metal members 21, 54 to at least elastically deform and adhere closely to the first metal members 11, 53, and in addition, some of the second metal members 21, 54 may also plastically deform, thereby fitting the two together.

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. In this way, if there are a large number of protrusions 53, there will be more point (line) contact at their tips, and conversely, the surface contact between the protrusions 53 will be smaller.

And because the numerous protrusions 53 press the entire surface outward in the radial direction H as indicated by the single arrow, the amount of elastic deformation (distributed amount of elastic deformation) near each protrusion 53 becomes small as indicated by the dashed line, making it difficult for each to deform flexibly. And even in the area between the protrusions 53, the area that is actually in surface contact becomes even smaller, which is thought to reduce adhesion.

In particular, as shown in FIG. 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.

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 in Figure 5(a), and conversely, the surface contact between the protrusions 15 is much greater. In addition, since the number of protrusions 15 is small and the overall amount of pressure applied outward in the radial direction H is small, it is possible to ensure a sufficient amount of elastic deformation (distributed amount of elastic deformation) near each protrusion 15. 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).

In addition, as shown in FIG. 1(b) in particular, in the arrangement region DR of a certain protrusion 15, adjacent protrusions 15 do not overlap with each other along the circumferential direction R (axial direction V), so that the area of surface contact between the protrusions 15 can be sufficiently secured.

In other words, in the present embodiment, compared to the configuration shown in FIG. 5(a), the second metal member 21 is configured to elastically deform gently near each protrusion 15 while suppressing the overall amount of deformation, and to ensure a sufficient area of surface contact. This is thought 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.

Also, referring to FIG. 4, when considering the state of adhesion due to elastic deformation, in the case of the first metal member 50 shown in FIG. 4(a), the second metal member 54 is elastically deformed by 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 (indicated by the arrow) is not restricted in any way. Therefore, for example, assuming that the second metal member 54 is not broken, if a force exceeding the bonding strength is applied in the axial direction V (the pushing direction during press-fitting or the opposite direction), the first metal member 50 will be removed from the second metal member 54.

The same is true for the first metal member 52 shown in FIG. 5B, where the second metal member 54 is elastically deformed by the press-in and comes into close contact with the first metal member 52 along the protrusion 51 as shown by the hatching, but the progress of the first metal member 52 in the extension direction of the protrusion 53 (indicated by the arrow) is not restricted in any way. Therefore, for example, assuming that the second metal member 54 is not broken, if a force exceeding the bonding strength is applied in the extension direction of the protrusion 53 (the pushing direction during press-in or the opposite direction), the first metal member 52 will be removed from the second metal member 54.

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 peripheral 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.

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 it from the second metal member 21, its progress is restricted by one of the portions PX of the arc-shaped protrusion 15 coming into contact with the second metal member 21.

In other words, the protrusion 15 formed on the first metal member 11 in this embodiment includes a restricting portion PX that restricts the first metal member 11, which is fitted into 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.

Therefore, even when attempting to remove the first metal member 11 from the second metal member 21, the restricting portion PX restricts the progress of the first metal member 11, 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 method.

Note that while FIG. 1C shows only a few restricting portions PX, if the protrusion 15 is formed in an arc shape, the entire protrusion 15 will become a restricting portion PX that restricts linear progression in the pressing direction (axial direction V) and in a direction inclined relative to the pressing direction (at least one of the inclined directions).

Specifically, for example, assuming that all conditions other than the shape of the protrusions 15, 51, and 53 are the same, if the removal force (removal load) when the protrusions 51 and 53 shown in Fig. 1(a) and (b) are formed is, for example, 20 kg to 30 kg, it can be improved to 200 kg to 300 kg by using the pattern of the protrusion 15 of this embodiment.

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 protrusions 15 in addition to elastic deformation.

Figure 7 is a side view showing another example of the protrusion 15.

The protrusion 15 is not limited to the above example, so long as it includes a restricting portion PX that restricts the first metal member 11, which is fitted into 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.

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

In this case, although they overlap in the circumferential direction, the length of the protrusions 15A and 15B is short, so the area of surface contact can be sufficiently secured.

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 shape, the restricting portion PX exists over the entire protrusion, but with this shape, if the second metal member 21 is scraped off by the press-fitting, the scraps can be prevented from being discharged to the outside.

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

As shown in FIG. 8, a hole 17 may be formed in a first metal member 11 that is difficult to deform, and a second metal member 21 that is easy to deform may be press-fitted into the hole 17.

In this case, a protrusion 15 that protrudes toward the second metal member 21 (inside) is formed on the peripheral surface (inner peripheral surface) 18 of the hole 17 of the first metal member 11, which is the contact surface of the second metal member 21. The pattern of the protrusion 15 in a side view is the same as that shown in Figures 1 and 5.

Even in this case, the protrusions 15 have a restricting portion PX that restricts linear progression 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.

Figure 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 on the contact surface with the second metal member 21 that protrudes toward the second metal member 21 and the protrusion 15 causes at least a part of the second metal member 21 to elastically deform.

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 the 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 approximately 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 (the lower end in the figure), and the tip portion 15T to the starting point S2 (the tip in the press-fitting direction) may be formed into a wedge shape that exhibits a gentle taper shape. 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.

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), the thickness (thickness in the axial direction V) of the first metal member 11 (FIG. 1(b), FIG. 1(d)) is made smaller than the thickness of the second metal member 21 (FIG. 1(c), FIG. 1(d)), and a support portion 27 that supports the first metal member 11 is provided on the inner peripheral surface 25 of the hole portion 24 of the second metal member 21, which is preferable for preventing the first metal member 11 from coming out in the axial direction. The support portion 27 protrudes inward in the radial direction H (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)).

In the case of the wedge-shaped protrusion 15 shown in Figs. (a) to (d), the diameter becomes smaller toward the tip in the press-fitting direction (the lower part in the figure), and there is a gentle taper from the tip in the press-fitting direction to the protrusion 15 (tip portion 15T), making it easier to press in and reducing the press-in force. In addition, because the protrusion 15 is wedge-shaped, the removal load (removal force) in the press-fitting direction can be increased.

Figure (e) shows a wedge-shaped projection 15 shown in Figure (a) in which the other base point S2 of the projection is located midway in the axial direction of the first metal member 11.

Even in this case, the diameter of the protrusion 15 becomes smaller toward the tip in the press-fit direction (lower in the figure), and the protrusion 15 (tip 15T) is tapered from the tip in the press-fit direction, making it easier to press in (reducing the press-in force). And because all of the protrusions 15 are wedge-shaped, the removal load (removal force) in the press-fit direction can be increased.

Furthermore, as shown in FIG. 4(f), the wedge-shaped protrusion 15 shown in FIG. 4(a) is not limited to being annular (a shape that is continuous in the circumferential direction R), but may be provided in multiple pieces separated in the circumferential direction R.

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-fit direction (the lower part in the figure), and there is a gentle taper from the tip in the press-fit direction to the protrusion 15 (tip portion 15T), making it easier to press in and reducing the press-in force. In addition, because the protrusion 15 is wedge-shaped, the removal load (removal force) in the press-fit direction can be increased.

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

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 different position in the axial direction V from both of the protrusion base points S1 and S2. In this case, the protrusion 15 may be continuous in the circumferential direction R as shown in FIG. 1(g), or, although not shown, may be provided in multiple parts separated in the circumferential direction R.

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

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).

Also, as shown in FIG. 1(h), the protrusions 15 shown in FIG. 1(a) (or the protrusions 15 shown in FIG. 1(g)) may be combined in multiple ways in the axial direction of the first metal member 11.

As described above, in the embodiment shown in FIG. 9, when the first metal member 11 is pressed into the second metal member 21, the second metal member 21 at least undergoes elastic deformation, or in addition to elastic deformation, undergoes plastic deformation, and deforms in such a way that a part of the inner peripheral surface 25 of the second metal member 21 is scraped off by the protrusion 15 (so that a groove is carved), so that the protrusion 15 and the inner peripheral surface 25 of the second metal member 21 are firmly fitted (fitted), and the first metal member 11 forms a joint 30 in which its outer peripheral surface 13 contacts the inner peripheral surface 25 of the hole portion 24 of the second metal member 21 (see FIG. (d)).

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 in the conventional case, and the press-in force (press-in load) is the same as in the conventional case, the removal load (removal force) can be significantly increased compared to the conventional case.

In other words, if it is sufficient to maintain the same level of pull-out 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 contributes to the miniaturization (weight reduction) of the parts.

In addition, by making parts smaller and lighter, costs can be reduced and layout freedom is improved.

Furthermore, while adhesives have traditionally been used to improve removal force, it is now possible to improve removal force without using adhesives.

It also makes it possible to downsize the press-fitting machine (reducing labor required).

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 product, a bearing part, or other pressed-in part) made of the second metal member 21 as reinforcement in a location where strength is required.

A joint 30 was formed using the joining member 10 shown in FIG. 9(a), and the pressing force and removal force were compared with a comparative example of a joint that does not have a protrusion 15.

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. The second metal member 21 is made of aluminum.

The comparative example joint does not have protrusions 15, the material of the inner metal member (the member corresponding to the first metal member in 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 in this embodiment) is aluminum, the same as in this embodiment. In addition, the other configurations (plate thickness, outer diameter, inner diameter, interference, and other shapes) are the same for both.

The press-in load (press-in force) and removal load (removal force, removal strength) were measured for the joint 30 of this embodiment and the joint 60 of the comparative example. The joint of the comparative example had a press-in load of 190 kgf and a removal strength of 190 kgf. On the other hand, the joint 30 of this embodiment had a press-in load of 200 kgf and a removal strength of 520 kgf.

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

In other words, if it is sufficient to maintain the same level of pull-out 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 the miniaturization (weight reduction) of the parts.

The present invention can be used to join multiple components.

REFERENCE SIGNS LIST 10: Joining member 11: First metal member 15: Protrusion 21: Second metal member 30: Joint body

Claims (9)

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: The protrusion has a wedge-shaped cross-sectional shape along the diameter of the first metal member.
The joining member according to claim 1 . 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. 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 . 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. 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: A joint body joined by the joining member according to any one of claims 1 to 6. 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: A bonded body bonded by the bonding method according to claim 8.

Images