WO2021210280A1

WO2021210280A1 - Structural member and method for manufacturing structural member

Info

Publication number: WO2021210280A1
Application number: PCT/JP2021/007892
Authority: WO
Inventors: 辰宗森
Original assignee: 株式会社神戸製鋼所
Priority date: 2020-04-14
Filing date: 2021-03-02
Publication date: 2021-10-21
Also published as: JP2021169104A

Abstract

A method for manufacturing a structural member (1) includes preparing an outside member (10) having an inner space (S) and an attenuation material (20) having a larger loss coefficient than the outside member (10), and crimping the attenuation material (20) to a specific portion (R) of the outside member (10) in the inner space (S).

Description

Structural members and manufacturing methods for structural members

The present invention relates to a structural member and a method for manufacturing the structural member.

Patent Document 1 discloses a method of joining a tube body and a wall surface body having a through hole. The method is a so-called rubber bulge bond. Specifically, the tube body is inserted into the through hole of the wall surface body, and the elastic body is inserted inside the tube body. Then, by applying pressure so as to sandwich the elastic body, the tubular body is expanded radially outward by the elastic body and is pressed against the inner wall of the through hole of the wall surface body.

Japanese Unexamined Patent Publication No. 51-133170

In the rubber bulge coupling of Patent Document 1, there is a possibility that the flexural rigidity and vibration damping characteristics of the bonded structural member may deteriorate at a specific portion where the tubular body is deformed. Patent Document 1 does not mention such a problem.

An object of the present invention is to improve the flexural rigidity and vibration damping characteristics of a specific part in a structural member and a method for manufacturing the structural member.

In the first aspect of the present invention, an outer member having an internal space and a damping material having a loss coefficient larger than that of the outer member are prepared, and the damping material is pressure-bonded to a specific portion of the outer member in the internal space. Provided is a method for manufacturing a structural member including the above.

According to this method, the flexural rigidity and damping characteristics of the specific part can be improved by crimping the damping material to the specific part of the outer member. Generally, the damping material is often attached to the outside of the outer member for ease of processing, but in the above method, the damping material is crimped to the inside of the outer member. Therefore, the appearance of the outer member is not impaired. Here, the specific portion refers to an arbitrary portion of the outer member, and the specific portion can be set, for example, at a position susceptible to deformation or a position subject to molding. The loss coefficient is one of the evaluation indexes of the vibration damping characteristic, and the larger the loss coefficient, the higher the damping characteristic. Further, the internal space of the outer member includes not only a closed space defined inside the box but also an open space defined by a recess.

A bulging portion may be formed on the outer member so that the internal space expands at the same time as the crimping of the damping material, and the specific portion may include the bulging portion.

According to this method, the forming of the bulging portion and the crimping of the damping material can be performed at the same time, so that the increase in man-hours can be suppressed. In particular, since the bulging portion is a portion where the bending rigidity and the damping characteristics may deteriorate, it is effective to press a damping material on the bulging portion to suppress the deterioration of the bending rigidity and the damping characteristics. .. Further, the bulging portion can be used to fit the hole portion of another member.

The bulging portion may be molded by rubber bulge molding or hydraulic molding.

According to this method, a forming force can be applied to the inside (inner surface) of the outer member via the damping material by rubber bulge molding or hydraulic molding, so that molding of the bulging portion and crimping of the damping material can be easily performed at the same time. Can be executed. Further, rubber bulge molding and hydraulic molding are more versatile than molding such as electromagnetic molding because there are few restrictions on the shape of the outer member to be molded.

The specific portion is set only at at least one of the bulging start portion, which is the boundary portion between the bulging portion and the non-bulging portion, and the maximum bulging portion, which is the most bulging portion in the bulging portion. May be done.

According to this method, the flexural rigidity and damping characteristics at at least one of the bulging start portion and the maximum bulging portion can be concentrated and improved. In particular, the flexural rigidity and damping characteristics of the bulging start portion and the maximum bulging portion tend to deteriorate. Therefore, in the above method, by crimping the damping material only at a position where the bending rigidity and the damping characteristic are likely to deteriorate, the bending rigidity and the damping characteristic at such a position are suppressed while suppressing the excessive use of the damping material. Deterioration can be concentrated and suppressed.

The damping material includes a first damping material having a relatively high loss coefficient and a second damping material having a relatively low loss coefficient, and the specific portion is a first specific portion for crimping the first damping material. And a second specific portion for crimping the second damping material, the first specific portion is a bulging start portion and the bulging portion which are boundary portions between the bulging portion and the other portion. The second specific portion may be set to at least one of the maximum bulging portions, which is the most bulging portion, and the second specific portion may be set to the bulging portion other than the first specific portion.

According to this method, the flexural rigidity and vibration damping characteristics at at least one of the bulging start portion and the maximum bulging portion can be further improved. As described above, the flexural rigidity and damping characteristics of the bulging start portion and the maximum bulging portion tend to deteriorate. Therefore, in the above method, the first damping material having a relatively high loss coefficient is crimped to a position where the flexural rigidity and the damping characteristics are likely to deteriorate, and the second damping material having a relatively low loss coefficient is applied to other parts. By crimping, the bending rigidity and vibration damping characteristics can be equalized.

The outer member and the damping material are both tubular, and the molding of the bulging portion may be a tube expansion molding for forming a tube-expanded portion.

According to this method, since the outer member is tubular, it is highly versatile as a structural member. For example, structural members can be used in vehicle bumper systems, steering supports, instrument panel reinforcements and bicycle frames.

In the method for manufacturing the structural member, an inner member which is tubular and has a loss coefficient smaller than that of the damping material is further prepared, and the inner member is inserted into the outer member to form the inner member. The damping material is arranged between the outer member and the bulging portion, and in the molding of the bulging portion, the expanded tube portion is formed on the outer member and at the same time the expanded tube portion is formed on the inner member. The expanded tube portion of the outer member and the expanded tube portion of the inner member may be included.

According to this method, the flexural rigidity and vibration damping characteristics of each tube-expanded portion can be improved by crimping a damping material to each tube-expanded portion between the inner member and the outer member. Since the expanded pipe portion has a bulging shape and is a joint portion between the inner member and the outer member, the flexural rigidity and the vibration damping characteristics are likely to deteriorate. In the above method, since the damping material is crimped to the portion where the bending rigidity and the damping characteristic are likely to deteriorate, the deterioration of the bending rigidity and the damping characteristic can be effectively suppressed.

The damping material may be provided with a cut extending in the pipe axis direction.

According to this method, the elasticity of the damping material in the radial direction can be improved by the cut. Therefore, the damping material can be more reliably crimped to the outer member.

The outer member has a tray shape having a recess that defines the internal space, and the molding of the bulging portion may be a molding that partially bulges the side wall portion of the recess.

According to this method, since the outer member is tray-shaped, it is highly versatile as a structural member. For example, structural members can be used in battery cases for vehicles and the like.

A second aspect of the present invention is a specific portion of the inner member and the outer member between the tubular inner member, the tubular outer member arranged outside the inner member, and the inner member and the outer member. The inner member and the outer member are provided with a damping material which is crimped to and has a larger loss coefficient than the outer member, and the inner member and the outer member are provided with a tube-expanded portion which is formed by expanding the tube so as to bulge outward in the radial direction. By being caulked to each other, the specific portion provides a structural member including the inner member and the expanded tube portion of the outer member.

According to this configuration, the flexural rigidity and vibration damping characteristics of the expanded tube portion can be improved by crimping the damping material against the expanded tube portion between the inner member and the outer member. The expanded pipe portion has a bulging shape and is a joint portion between an inner member and an outer member, and such a portion tends to deteriorate flexural rigidity and vibration damping characteristics. In the above configuration, since the damping material is pressure-bonded to the portion where the bending rigidity and the damping characteristic are likely to deteriorate, the deterioration of the bending rigidity and the damping characteristic can be effectively suppressed. Further, since the structure is such that two pipe members are joined, the versatility as the structural member 1 is high. For example, structural members can be used in vehicle bumper systems, steering supports, instrument panel reinforcements and bicycle frames.

According to the present invention, in the structural member and the method for manufacturing the structural member, since the damping material is crimped to the specific portion, the bending rigidity and the vibration damping characteristic of the specific portion are improved.

Sectional drawing of the structural member which concerns on 1st Embodiment of this invention. The first cross-sectional view which shows the manufacturing method of the structural member of FIG. A second cross-sectional view showing a method of manufacturing the structural member of FIG. A third cross-sectional view showing a method of manufacturing the structural member of FIG. A fourth cross-sectional view showing a method of manufacturing the structural member of FIG. FIG. 5 is a fifth cross-sectional view showing a method of manufacturing the structural member of FIG. A side view showing an analysis model. A graph showing the relationship between the excitation force and the excitation frequency as analysis conditions. A graph showing the relationship between acceleration and frequency as an analysis result. FIG. 3 is a cross-sectional view of a structural member showing a first modification of the first embodiment. FIG. 3 is a cross-sectional view of a structural member showing a second modification of the first embodiment. FIG. 3 is a cross-sectional view of a structural member showing a third modification of the first embodiment. The cross-sectional view of the structural member which concerns on 2nd Embodiment. The first cross-sectional view which shows the manufacturing method of the structural member of FIG. A second cross-sectional view showing a method of manufacturing the structural member of FIG. 13. FIG. 3 is a third cross-sectional view showing a method of manufacturing the structural member of FIG. 13. FIG. 4 is a fourth cross-sectional view showing a method of manufacturing the structural member of FIG. 13. FIG. 5 is a fifth cross-sectional view showing a method of manufacturing the structural member of FIG. 13. FIG. 6 is a sixth cross-sectional view showing a method of manufacturing the structural member of FIG. 13. Sectional drawing of the structural member which concerns on 3rd Embodiment. A first cross-sectional view showing a method of manufacturing the structural member of FIG. 20. A second cross-sectional view showing a method of manufacturing the structural member of FIG. 20. A third cross-sectional view showing a method of manufacturing the structural member of FIG. 20. A fourth cross-sectional view showing a method of manufacturing the structural member of FIG. 20. FIG. 5 is a fifth cross-sectional view showing a method of manufacturing the structural member of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

(First Embodiment)
FIG. 1 shows a cross-sectional view of the structural member 1 of the first embodiment. The structural member 1 of the present embodiment has an outer member 10 and a damping member 20.

The outer member 10 is tubular and extends in the L direction of the pipe axis. In the present embodiment, the outer member 10 has a circular tubular shape. An internal space S is defined inside the outer member 10. The outer member 10 has a tube-expanded portion (bulging portion) 11 that has been tube-expanded so as to expand the internal space S, and a tubular portion 12 that has not undergone tube-expansion molding and maintains the original circular tubular shape. There is. The outer member 10 is made of, for example, an aluminum alloy. However, the shape and material of the outer member 10 are not particularly limited.

The damping material 20 is tubular and extends in the same pipe axis L direction as the outer member 10. In the present embodiment, the damping material 20 is a circular tube shorter than the outer member 10. The outer diameter of the damping material 20 is smaller than the inner diameter of the outer member 10. The damping material 20 is arranged in the internal space S of the outer member 10, and is crimped to the inner surface of the expanded pipe portion 11. Therefore, when viewed in a cross section perpendicular to the pipe axis L, the outer member 10 and the damping material 20 are arranged in close contact with each other concentrically. Further, when viewed in cross section including the pipe shaft L (see FIG. 1), the damping material 20 is crimped to the specific portion R. The specific portion R here is a portion of the outer member 10 including the expanded tube portion 11. More specifically, the specific portion R is set to the entire expanded tube portion 11 and a part of the tubular portion 12. Further, the damping material 20 may be made of, for example, a polyurethane or epoxy-based resin.

The loss coefficient of the damping material 20 is designed to be larger than the loss coefficient of the outer member 10. The loss coefficient is one of the evaluation indexes of the vibration damping characteristic, and the larger the loss coefficient, the higher the damping characteristic. The magnitude of the loss coefficient depends on the material and thickness of the member. In general, the more flexible the material, the larger the loss coefficient, and the thicker the member, the larger the loss coefficient. Therefore, from the viewpoint of improving the flexural rigidity and damping characteristics of the structural member 1, the damping material 20 is preferably a more flexible material (lower Young's modulus) than the outer member 10 and is thick to a certain extent.

In the method for manufacturing the structural member 1 having the above configuration, the steps shown in FIGS. 2 to 6 are executed in order.

With reference to FIG. 2, a fixing jig 30 having a fixed position is prepared. The fixing jig 30 is set in, for example, a press machine (not shown) so that its position does not move. The fixing jig 30 is, for example, cylindrical and has a flat surface 31 for receiving a pressing force, which will be described later. The flat surface 31 is a surface perpendicular to the pipe axis L and flat.

With reference to FIG. 3, the outer member 10 is set on the fixing jig 30. At this time, the expanded tube portion 11 (see FIG. 1) is not formed on the outer member 10. Therefore, the outer member 10 is composed of only the tubular portion 12 having a uniform cross-sectional shape. Then, the fixing jig 30 is arranged by aligning the flat surface 31 with the portion of the outer member 10 that forms the expanded tube portion 11.

With reference to FIG. 4, the damping material 20 is arranged in the internal space S of the outer member 10. Specifically, the damping material 20 is arranged according to a portion (specific portion) forming the expanded tube portion 11 (see FIG. 1). An adhesive is applied to the outer surface of the damping material 20. Therefore, the position of the damping material 20 is fixed by being attached to the inner surface of the outer member 10. Depending on the material of the damping material 20, it may not be necessary to apply the adhesive.

With reference to FIG. 5, the elastic body 40 is arranged inside the damping material 20. The elastic body 40 is, for example, a columnar shape having a diameter slightly smaller than the inner diameter of the damping material 20. In the tube axis L direction, the length of the elastic body 40 is longer than the length of the damping material 20. The material of the elastic body 40 may be, for example, urethane rubber, chloroprene rubber, CNR rubber (chloroprene rubber and nitrile rubber), or silicon rubber. Preferably, the hardness of the elastic body 40 is 30 or more on the shore A.

With reference to FIG. 6, a moving jig 50 having a flat surface 51 for applying a pressing force to the elastic body 40 is prepared. The flat surface 51 is a surface perpendicular to the pipe axis L and flat. Then, the elastic body 40 is pressed toward the fixing jig 30 by the moving jig 50. That is, in the pipe axis L direction, the elastic body 40 is pressed so as to be sandwiched between the flat surface 51 of the moving jig 50 and the flat surface 31 of the fixing jig 30. The pressing may be performed by a press machine. By the pressing, the elastic body 40 is compressed in the tube axis L direction and bulges outward in the radial direction. As a result, the damping material 20 is crimped to the outer member 10, and the outer member 10 is tube-expanded to form the tube-expanded portion 11 (see FIG. 1). A molding method using such an elastic body 40 is called rubber bulge molding.

With reference to FIG. 1 again, after the completion of the crimping and tube expansion molding, the elastic body 40 whose pressing force is released is restored to its original shape by its own elastic force, and can be easily removed. In this way, the structural member 1 is manufactured.

The manufacturing method of the structural member 1 described above is an example, and is not limited thereto. For example, the order of the steps of FIGS. 3 to 5 may be changed, the steps of FIGS. 4 and 5 may be executed at the same time, and the steps of FIGS. 5 and 6 may be executed at the same time. Further, tube expansion molding is not essential in the process of FIG. That is, the damping material 20 is only crimped to the outer member 10, and the expanded pipe portion 11 may not be provided in the structural member 1 of FIG.

With reference to FIGS. 7 to 9, the analysis performed to confirm the effect of improving the flexural rigidity and vibration damping characteristics of the structural member 1 having the above configuration will be described.

FIG. 7 is a side view showing an analysis model of the structural member 1. In FIG. 7, half of the structural member 1 is shown in the L direction of the pipe axis. Although the inside of the structural member 1 is not shown, the damping material 20 is crimped to the inner surface of the outer member 10 as in the structural member 1 shown in FIG. Since the finite element method is used in the analysis, the analysis model of the structural member 1 is divided into a plurality of elements and shown.

The analysis conditions were set as follows. The outer member 10 is an aluminum material having a thickness of 2.0 mm. The Young's modulus of the outer member 10 is about 70 GPa. The loss coefficient of the outer member 10 is 0.01. The damping material 20 has a thickness of 2.0 mm and a density equivalent to that of aluminum. The Young's modulus of the damping material 20 is about 600 MPa. The loss coefficient of the damping material 20 is 0.45.

Further, as an analysis condition, the end portion of the structural member 1 in the pipe axis L direction is set as the evaluation point P1, and the point 100 mm away from the evaluation point P1 is set as the excitation point P2. The arrow at the excitation point P2 in FIG. 7 indicates the excitation direction. Further, a portion 100 mm away from the excitation point P2 is the swelling start portion P3. The bulging start portion P3 is a boundary portion between the expanded tube portion (bulging portion) 11 and the non-bulging portion. Further, in FIG. 7, the maximum bulging portion P4 that bulges most in the expanded tube portion 11 is also shown. In the analysis, the displacement of the element of the maximum bulging portion P4 was fixed and the excitation force was applied to the excitation point P2.

FIG. 8 is a graph showing the relationship between the excitation force and the excitation frequency at the excitation point P2. The horizontal axis represents the frequency (Hz), and the vertical axis represents the exciting force (N). A constant excitation force of 1.0 N was applied to the excitation point P2 in the frequency range of 300 to 2500 Hz. The graph of FIG. 9 shows the analysis result at the evaluation point P1 at this time.

In FIG. 9, the horizontal axis represents frequency (Hz) and the vertical axis represents acceleration (mm / S ² ). In FIG. 9, the analysis result of the structural member 1 of the present embodiment is shown as a curve C1, and the analysis result of another structural member whose other analysis conditions are the same as those of the present embodiment without using the damping material 20 is a curve. It is indicated by C2. Further, in FIG. 9, the peak value portion of the curves C1 and C2 is enlarged and shown (see the broken line circle).

The peak value of curve C1 is lower than the peak value of curve C2. Therefore, it can be confirmed that the vibration is suppressed and the vibration damping characteristics are improved by using the damping material 20. Further, the curve C1 is located on the higher frequency side than the curve C2 as a whole. In particular, the frequency at which the peak value of the curve C1 is taken is higher by Δf than the frequency at which the peak value of the curve C2 is taken. Therefore, it can be confirmed that the structural member 1 is hardened and the flexural rigidity is improved by using the damping material 20.

According to the present embodiment, by crimping the damping material 20 to the specific portion R of the outer member 10, the bending rigidity and the vibration damping characteristics of the specific portion R can be improved. Generally, the damping material 20 is often attached to the outside of the outer member 10 for ease of processing, but in the present embodiment, the damping material 20 is crimped to the inside of the outer member 10. Therefore, the appearance of the outer member 10 is not impaired.

Further, since the molding of the expanded pipe portion 11 and the crimping of the damping material 20 can be performed at the same time, an increase in man-hours can be suppressed. In particular, since the expanded tube portion 11 is a portion where the bending rigidity and the damping characteristics may deteriorate, it is possible to suppress the deterioration of the bending rigidity and the damping characteristics by crimping the damping material 20 to the expanded tube portion 11. It is valid. Further, the expanded tube portion 11 can be used to fit the hole portion of another member.

Further, since the forming force can be applied to the inside (inner surface) of the outer member 10 via the damping material 20 by the rubber bulge molding, the molding of the expanded tube portion 11 and the crimping of the damping material 20 can be easily performed at the same time. Further, rubber bulge molding is highly versatile because there are few restrictions on the shape of the outer member to be molded as compared with molding such as electromagnetic molding.

Further, since the outer member 10 is tubular, it is highly versatile as a structural member 1. Examples of application of the structural member 1 of the present embodiment include a bumper system for a vehicle, a steering support, an instrument panel reinforcement, a frame for a bicycle, and the like. Further, in such a structural member 1 which can be large or long, it is preferable that the specific portion R is set at a position out of reach from both ends of the outer member 10.

(First modification)
With reference to FIG. 10, in the first modification of the present embodiment, the specific portion R for crimping the damping material 20 is set only at at least one of the bulging start portion P3 and the maximum bulging portion P4. In the example of FIG. 10, two bulging start portions P3 and one maximum bulging portion P4 are set as specific portions R, and the damping material 20 is crimped only to the specific portion R. In other words, the damping material 20 is not crimped to the portion other than the two bulging start portions P3 and the maximum bulging portion P4.

According to this modification, the flexural rigidity and damping characteristics at at least one of the bulging start portion P3 and the maximum bulging portion P4 can be concentrated and improved. In particular, the bulging start portion P3 and the maximum bulging portion P4 tend to deteriorate in bending rigidity and vibration damping characteristics. Therefore, in the above method, by crimping the damping material 20 only at a position where the bending rigidity and the damping characteristic are likely to deteriorate, the bending rigidity and the damping material 20 at such a position are suppressed while suppressing the excessive use of the damping material 20. Deterioration of characteristics can be concentrated and suppressed.

(Second modification)
With reference to FIG. 11, in the second modification of the present embodiment, as the damping material 20, the first damping material 21 having a relatively high loss coefficient and the second damping material 22 having a relatively low loss coefficient are used. prepare. The specific portion R includes a first specific portion R1 for crimping the first damping material 21 and a second specific portion R2 for crimping the second damping material 22. The first specific site R1 can be set at at least one of the swelling start portion P3 and the maximum bulge portion P4. The second specific portion R2 may be set to the expanded tube portion (bulging portion) 11 excluding the first specific portion R1.

In the example of FIG. 11, two bulging start portions P3 and one maximum bulging portion P4 are set as the first specific portion R1, and the first damping material 21 is crimped. Further, the expanded tube portion 11 excluding the first specific portion R1 is set as the second specific portion R2, and the second damping material 22 is crimped.

According to this modification, the flexural rigidity and vibration damping characteristics at at least one of the bulging start portion P3 and the maximum bulging portion P4 can be further improved. As described above, the bulging start portion P3 and the maximum bulging portion P4 tend to have deteriorated bending rigidity and damping characteristics. Therefore, in the above method, the first damping material 21 having a relatively high loss coefficient is crimped to a position where the flexural rigidity and damping characteristics are likely to deteriorate, and the second damping material 21 having a relatively low loss coefficient is crimped to other parts. By crimping 22, the bending rigidity and vibration damping characteristics can be equalized.

(Third modification example)
With reference to FIG. 12, in the third modification of the present embodiment, the damping material 20 is provided with a cut 23 extending in the pipe axis L direction. Note that FIG. 12 shows a cross section perpendicular to the pipe axis L at the maximum bulging portion P4 of the structural member 1.

According to this modification, the elasticity of the damping material 20 in the radial direction can be improved by the cut 23. Therefore, the damping material 20 can be more reliably crimped to the outer member 10.

(Second Embodiment)
The structural member 1 of the second embodiment shown in FIG. 13 has an inner member 60. Except for the inner member 60, it is substantially the same as the structural member 1 of the first embodiment. Therefore, the description of the same part as that of the first embodiment may be omitted.

The inner member 60 is a tubular shape that can be inserted into the outer member 10. In the present embodiment, the inner member 60 has a circular tubular shape and extends in the L direction of the pipe axis. The inner member 60 is partially arranged in the inner space S of the outer member 10. In the radial direction, the damping material 20 is arranged between the inner member 60 and the outer member 10. That is, the inner member 60, the outer member 10, and the damping material 20 form a triple pipe sharing the pipe shaft L.

The inner member 60 has a tube-expanded portion (bulging portion) 61 that has been tube-expanded and a tubular portion 62 that has not undergone tube-expansion molding and maintains the original circular tubular shape. The inner member 60 and the outer member 10 are caulked and joined to each other by the expanded

pipe portions

11, 61. Further, the inner member 60 is made of the same aluminum alloy as the outer member 10, for example.

The damping material 20 is crimped to the inner member 60 and the outer member 10 between the inner member 60 and the outer member 10. The damping material 20 has a larger loss coefficient than the inner member 60 and the outer member 10. The specific portion R for crimping the damping material 20 includes the expanded tube portion 61 of the inner member 60 and the expanded tube portion 11 of the outer member 10. More specifically, the specific portion R is set to the entire expanded

tube portion

11,61 and a part of the

tubular portion

12, 62.

In the method for manufacturing the structural member 1 having the above configuration, the steps shown in FIGS. 14 to 19 are sequentially executed.

With reference to FIG. 14, a fixing jig 30 having a fixed position is prepared.

With reference to FIG. 15, the inner member 60 is set on the fixing jig 30. At this time, the expanded tube portion 61 (see FIG. 13) is not formed on the inner member 60. Therefore, the inner member 60 is composed of only the tubular portion 62 having a uniform cross-sectional shape. Then, the fixing jig 30 is arranged by aligning the flat surface 31 with the portion of the inner member 60 that forms the expanded tube portion 61.

With reference to FIG. 16, the damping material 20 is arranged on the outside of the inner member 60 in accordance with the portion (specific portion) forming the expanded tube portion 61. An adhesive is applied to the inner surface of the damping material 20. Therefore, the position of the damping material 20 is fixed by being attached to the outer surface of the inner member 60. Depending on the material of the damping material 20, it may not be necessary to apply the adhesive.

With reference to FIG. 17, the outer member 10 is arranged outside the damping material 20. At this time, the expanded tube portion 11 (see FIG. 13) is not formed on the outer member 10. Therefore, the outer member 10 is composed of only the tubular portion 12 having a uniform cross-sectional shape. Specifically, the outer member 10 is arranged according to a portion (specific portion) forming the expanded tube portion 11. An adhesive is applied to the outer surface of the damping material 20. Therefore, the position of the damping material 20 is fixed by being attached to the inner surface of the outer member 10.

With reference to FIG. 18, the elastic body 40 is arranged inside the inner member 60. The elastic body 40 is, for example, a columnar body having a diameter slightly smaller than the inner diameter of the inner member 60. In the tube axis L direction, the length of the elastic body 40 is longer than the length of the damping material 20.

With reference to FIG. 19, the moving jig 50 is prepared, and the elastic body 40 is pressed toward the fixing jig 30 by the moving jig 50. That is, in the pipe axis L direction, the elastic body 40 is pressed so as to be sandwiched between the flat surface 51 of the moving jig 50 and the flat surface 31 of the fixing jig 30. The pressing may be performed by a press machine. By the pressing, the elastic body 40 is compressed in the tube axis L direction and bulges outward in the radial direction. As a result, the expanded tube portion 61 is formed on the inner member 60, the expanded tube portion 11 is formed on the outer member 10, and the damping material 20 is further crimped to the inner member 60 and the outer member 10.

With reference to FIG. 13 again, after the completion of the crimping and the tube expansion molding, the elastic body 40 whose pressing force is released is restored to its original shape by its own elastic force, and can be easily removed. In this way, the structural member 1 is manufactured.

The manufacturing method of the structural member 1 described above is an example, and is not limited thereto. For example, the steps of FIGS. 18 may be executed at arbitrary timings between the steps of FIGS. 14 to 18, the steps of FIGS. 15 and 16 may be executed at the same time, and the steps of FIGS. 16 and 17 may be executed at the same time. The

steps

17 and 18 may be performed at the same time.

According to the present embodiment, by crimping the damping material 20 against the expanded

tube portions

61 and 11 between the inner member 60 and the outer member 10, the flexural rigidity and vibration damping characteristics of the expanded

tube portions

61 and 11 can be obtained. Can be improved. Since the expanded

pipe portions

61 and 11 have a bulging shape and serve as a joint portion between the inner member 60 and the outer member 10, the bending rigidity and vibration damping characteristics are likely to deteriorate. In the present embodiment, since the damping material 20 is crimped to the portion where the bending rigidity and the damping characteristic are likely to deteriorate, the deterioration of the bending rigidity and the damping characteristic can be effectively suppressed.

Further, since the structure is such that two pipe members (inner member 60 and outer member 10) are joined, the versatility as the structural member 1 is high. The structural member 1 of the present embodiment can be used, for example, for a bumper system for a vehicle, a steering support, an instrument panel reinforcement, a bicycle frame, and the like.

(Third Embodiment)
In the structural member 1 of the third embodiment shown in FIG. 20, the shapes of the outer member 10 and the damping

members

20A and 20B are different from those of the first embodiment. Except for these configurations, it is substantially the same as the structural member 1 of the first embodiment. Therefore, the description of the same part as that of the first embodiment may be omitted. In FIG. 20, half of the structural member 1 is shown.

The outer member 10 has a tray shape having a recess 13 that defines the internal space S. The outer member 10 has a bottom wall portion 14, a bulging portion 15, a neck portion 16, and a flange portion 17. The bottom wall portion 14 constitutes the bottom surface of the recess 13 of the outer member 10. The bulging portion 15 rises vertically from the bottom wall portion 14 and constitutes the side surface of the recess 13. The neck portion 16 is formed so as to be continuous from the bulging portion 15 and narrow the recess 13 from the bulging portion 15. In other words, the bulging portion 15 is formed so as to bulge from the neck portion 16. The flange portion 17 extends outward in parallel with the bottom wall portion 14 continuously so as to be curved from the neck portion 16.

The damping material 20A is crimped to the inner surface of the outer member 10, and the damping material 20B is crimped to the outer surface of the outer member 10. The damping

materials

20A and 20B are crimped to a part (specific portion R) of the neck portion 16 and the bulging portion 15 of the outer member 10. The damping

materials

20A and 20B are both the same member, and have a larger loss coefficient than the outer member 10. The damping

materials

20A and 20B can be made of, for example, a polyurethane or epoxy-based resin.

In the method for manufacturing the structural member 1 having the above configuration, the steps shown in FIGS. 21 to 25 are sequentially executed. It should be noted that FIGS. 21 to 25 are shown rotated by 90 degrees with respect to FIG. 20.

With reference to FIG. 21, a mold 70 having a fixed position is prepared. The mold 70 has a shape complementary to the outer member 10 shown in FIG. Specifically, the mold 70 includes a bottom wall forming portion 71 forming the bottom wall portion 14, a bulging forming portion 72 forming the bulging portion 15, a neck forming portion 73 forming the neck portion 16, and a flange portion. It has a flange forming portion 74 forming the 17.

With reference to FIG. 22, the damping material 20B is arranged over the neck forming portion 73 and the bulging forming portion 72 of the mold 70. Since the damping material 20B is a flexible member, it can be arranged along the shapes of the neck forming portion 73 and the bulging forming portion 72.

With reference to FIG. 23, the blank material 10 is placed on the mold 70 on which the damping material 20B is placed. Here, the same reference numerals are used for the blank material 10 and the outer member 10 because they indicate the same members before and after molding. The blank material 10 includes a bottom wall portion 14, a flat side wall portion 18 rising vertically from the bottom wall portion 14, and a flange portion 17 extending outward in parallel with the bottom wall portion 14 so as to be curved from the side wall portion 18. And have. That is, the blank material 10 does not have the neck portion 16 and the bulging portion 15. In a later step, the side wall portion 18 of the blank material 10 is formed into the neck portion 16 and the bulging portion 15.

With reference to FIG. 24, the damping material 20A is arranged inside the blank material 10 (internal space S). Specifically, the damping material 20A is arranged so as to be a boundary portion between the neck portion 16 and the bulging portion 15. An adhesive is applied to the outer surface of the damping material 20A. Therefore, the position of the damping material 20A is fixed by being attached to the inner surface of the blank material 10. An adhesive is also applied to the inner surface of the damping material 20B, and the damping material 20B is attached to the blank material 10 at the time of crimping, which will be described later. Depending on the materials of the damping

materials

20A and 20B, it may not be necessary to apply the adhesive.

With reference to FIG. 25, the hydraulic member 41 is arranged inside the blank material 10 and the damping material 20A. The hydraulic member 41 is formed by coating a liquid with a rubber film. Only a part of the hydraulic member 41 is shown for the sake of clarity. The type of liquid is not particularly limited and may be oil, water, or the like. By pressing the hydraulic member 41 against the blank material 10, the blank material 10 is formed along the mold 70 and has the shape of the outer member 10 (see FIG. 20). That is, the side wall portion 18 of the blank material 10 is formed so as to partially bulge, and the side wall portion 18 is formed into the neck portion 16 and the bulging portion 15. At the same time, the damping

materials

20A and 20B are pressed against the blank material 10 (that is, the outer member 10). A molding method using such a hydraulic member 41 is called hydraulic molding. Hydraulic molding may also be referred to as flex forming.

With reference to FIG. 20 again, after the completion of crimping and swelling molding, the hydraulic member 41 whose pressing force is released is restored to its original shape and can be easily removed. In this way, the structural member 1 is manufactured.

The manufacturing method of the structural member 1 described above is an example, and is not limited thereto. For example, the step shown in FIG. 22 may be omitted. That is, the damping material 20B crimped to the outer surface of the outer member 10 may be omitted.

According to the present embodiment, since the forming force can be applied to the outer member 10 via the damping material 20A by hydraulic molding, the forming of the bulging portion 15 and the crimping of the damping material 20A can be easily performed at the same time. In the present embodiment, crimping of the damping material 20B can be performed at the same time. Further, the hydraulic molding is highly versatile because there are few restrictions on the shape of the outer member 10 to be molded as compared with molding such as electromagnetic molding.

Further, since the outer member 10 has a tray shape, it is highly versatile as a structural member 1. The structural member 1 of the present embodiment can be used, for example, in a battery case for a vehicle.

Although the specific embodiments of the present invention and variations thereof have been described above, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention. For example, an embodiment of the present invention may be a combination of individual embodiments and the contents of modifications thereof as appropriate.

1 Structural member 10 Outer member (blank material)
11 Expanded tube (bulging part)
12 Tubular part 13 Recession 14 Bottom wall part 15 Protruding part 16 Neck part 17 Flange part 18

Side wall part

20, 20A, 20B Damping material 21 1st damping material 22 2nd damping material 23 Cut 30 Fixing jig 31 Flat surface 40 Elastic body 41 Hydraulic member 50 Moving jig 51 Flat surface 60 Inner member 61 Expanded pipe part (bulging part)
62 Tubular part 70 Mold 71 Bottom wall forming part 72 Swelling forming part 73 Neck forming part 74 Flange forming part S Internal space R Specific part R1 First specific part R2 Second specific part P1 Evaluation point P2 Vibration point P3 Expansion Start part P4 Maximum bulge part

Claims

An outer member having an internal space and a damping material having a larger loss coefficient than the outer member are prepared.
A method for manufacturing a structural member, which comprises crimping the damping material to a specific portion of the outer member in the internal space.
A bulging portion is formed on the outer member so that the internal space expands at the same time as the crimping of the damping material.
The method for manufacturing a structural member according to claim 1, wherein the specific portion includes the bulging portion.
The method for manufacturing a structural member according to claim 2, wherein the bulging portion is molded by rubber bulge molding or hydraulic molding.
The specific portion is set only at at least one of the bulging start portion, which is the boundary portion between the bulging portion and the non-bulging portion, and the maximum bulging portion, which is the most bulging portion in the bulging portion. The method for manufacturing a structural member according to claim 2 or 3.
The damping material includes a first damping material having a relatively high loss coefficient and a second damping material having a relatively low loss coefficient.
The specific portion includes a first specific portion for crimping the first damping material and a second specific portion for crimping the second damping material.
The first specific portion is set at at least one of a bulging start portion which is a boundary portion between the bulging portion and the other portion and a maximum bulging portion which is the most bulging portion in the bulging portion. ,
The method for manufacturing a structural member according to claim 2 or 3, wherein the second specific portion is set in the bulging portion excluding the first specific portion.
The outer member and the damping material are both tubular and have a tubular shape.
The method for manufacturing a structural member according to claim 2 or 3, wherein the molding of the bulging portion is a tube expansion molding for forming a tube-expanded portion.
An inner member which is tubular and has a smaller loss coefficient than the damping material is further prepared.
The inner member is inserted into the outer member,
The damping material is arranged between the inner member and the outer member, and the damping material is arranged.
In the molding of the bulging portion, a tube-expanded portion is formed on the outer member and at the same time, a tube-expanded portion is formed on the inner member.
The method for manufacturing a structural member according to claim 6, wherein the specific portion includes the expanded tube portion of the outer member and the expanded tube portion of the inner member.
The method for manufacturing a structural member according to claim 6, wherein the damping material is provided with a cut extending in the pipe axis direction.
The outer member has a tray shape having a recess that defines the internal space.
The method for manufacturing a structural member according to claim 2 or 3, wherein the molding of the bulging portion is a molding in which the side wall portion of the recess is partially bulged.
With a tubular inner member,
A tubular outer member arranged outside the inner member and
A damping material that is crimped to a specific portion of the inner member and the outer member between the inner member and the outer member and has a loss coefficient larger than that of the inner member and the outer member is provided.
The inner member and the outer member are caulked and joined to each other by providing a tube-expanded portion formed so as to bulge outward in the radial direction.
The specific portion is a structural member including the inner member and the expanded tube portion of the outer member.