JP2019002420A - Damping member, method of manufacturing the same, and method of manufacturing structure - Google Patents

Abstract

To provide a damping member having an improved damping characteristic.SOLUTION: A damping member inserted into a cylinder includes a formed body. The formed body includes a plurality of base parts, and a connection part connecting two adjacent ones of the base parts. The connection part is configured to be foldable between the two adjacent base parts.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vibration damping member, a method for manufacturing the same, and a method for manufacturing a structure.

  For example, it is known to form a resin material in a structure such as a car body of an automobile. For example, Patent Document 1 describes disposing an annular foam material in a cylindrical body constituting a car body of an automobile.

JP 2007-90542 A

  Although the vibration damping performance can be ensured to some extent by the configuration of Patent Document 1, it is desired to further improve the vibration damping performance.

  The present invention has been made in view of such circumstances, and provides a vibration damping member with improved vibration damping performance.

  According to the present invention, the damping member is inserted into a cylinder, and the damping member includes a molded body, and the molded body includes a plurality of base portions and two adjacent ones of the plurality of base portions. There is provided a vibration damping member that includes a connecting portion that connects two base portions, and the connecting portion is configured to be foldable between the two adjacent base portions.

  The present inventor has intensively studied to improve the vibration damping performance of the vibration damping member. As a result, the vibration damping performance is improved by configuring the vibration damping member inserted into the cylinder to press the cylinder from the inside. I noticed that And when the structure which enables a damping member to press a cylinder from the inner side was examined, it connected so that a connection part might be folded between two adjacent bases among a plurality of bases which constitute a forming object. By configuring the part, it was found that a strong restoring force was generated in the connecting part, and the base of the molded body pressed the cylinder from the inside by the restoring force generated in the connecting part, and the present invention was completed.

Hereinafter, various embodiments of the present invention will be exemplified. The following embodiments can be combined with each other.
Preferably, the connecting part includes first and second outer hinge parts and an inner hinge part provided between the first and second outer hinge parts, and the inner hinge part can be bent in a direction opposite to the first and second outer hinge parts. It is configured.
Preferably, the connection part includes a first connection base between the first outer hinge part and the inner hinge part, and a second connection base between the second outer hinge part and the inner hinge part, The member includes an elastic member between surfaces of the first and second connection bases facing each other when the connection part is bent at the inner hinge part.
Preferably, the elastic member is made of a nonwoven fabric.
Preferably, the elastic member is integrally formed with the molded body.
Preferably, the molded body has a hollow portion.
Preferably, the molded body is a foam molded body.

  According to another aspect of the present invention, there is provided a method for manufacturing a vibration damping member as described above, wherein a parison forming step of forming a parison by extruding a molten resin and placing the parison between a pair of split molds, and the split metal A molding step of forming the molded body by performing mold clamping of the mold to form the molded body, and compressing the parison with the divided mold when clamping the divided mold; A method of manufacturing a damping member is provided in which the connecting portion is formed.

  According to still another aspect of the present invention, there is provided a structure manufacturing method including a step of inserting a damping member into a cylinder, wherein the damping member is the damping member described above, and the damping member is provided. A structure manufacturing method is provided in which the vibration damping member is inserted into the cylindrical body in a state where the vibration member is folded at the connecting portion.

It is a perspective view which shows the structure of the damping member 1 of one Embodiment of this invention. 2A is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 2B shows a state where the elastic member 3 is not shown in FIG. 2A. FIG. 3A shows a state where an external force is applied to the damping member 1 and the damping member 1 is folded at the connecting portion 8, and FIG. 3B is an enlarged view of the vicinity of the end face of the damping member 1 in FIG. 1A. A state after the damping member 1 is inserted into the cylinder 5 in a state where the damping member 1 is folded at the connecting portion 8 is shown. An example of the molding machine 6 which can be used with the manufacturing method of the damping member 1 of one Embodiment of this invention is shown. In FIG. 5, the shapes of the split molds 19 and 20 are simplified. It is BB sectional drawing in FIG. 4 which shows a parison formation process. It is sectional drawing of the same cross section as FIG. 5 which shows a formation process.

  Hereinafter, embodiments of the present invention will be described. Various characteristic items shown in the following embodiments can be combined with each other. In addition, the invention is independently established for each feature.

1. Configuration of Damping Member A configuration of the damping member 1 according to an embodiment of the present invention will be described with reference to FIGS. The damping member 1 is a member for reducing sound propagation through the cylinder 5 by suppressing vibration of the cylinder 5 by being inserted into the cylinder 5. The cylindrical body 5 is, for example, a reinforcement in an instrument panel of an automobile, has a pipe shape, and has a circular inner cross section, for example.

  The vibration damping member 1 includes a molded body 2 and an elastic member 3.

  The molded body 2 includes a first base portion 2a and second base portions 2b provided on both sides thereof. The base portions 2 a and 2 b are connected to each other by a connecting portion 8. Therefore, the molded body 2 has a configuration in which three base portions are connected by two connecting portions 8. The connecting portion 8 is configured to be foldable between the base portions 2a and 2b. In order from the base portion 2a side, the first outer hinge portion 8a, the first connecting base 8b, the inner hinge portion 8c, the second connecting base 8d, A second outer hinge portion 8e is provided.

  As shown in FIG. 3B, in a state where the connecting portion 8 is folded, the outer hinge portions 8a and 8e are located on the outer side of the molded body 2, and the inner hinge portion 8c is a molded body rather than the outer hinge portions 8a and 8e. 2 is located inside. When the connecting portion 8 is folded, the outer hinge portions 8a and 8e are mountain-folded and the inner hinge portion 8c is valley-folded when viewed from the outside of the molded body 2. That is, the inner hinge portion 8c is bent in the opposite direction to the outer hinge portions 8a and 8e. The connecting portion 8 is folded so that the connecting bases 8b and 8d are sandwiched between the base portions 2a and 2b. The hinge portions 8a, 8c and 8e are preferably thinner than the connection bases 8b and 8d. The ratio of the thickness T2 of the hinge portions 8a, 8c, 8e to the thickness T1 of the connection bases 8b, 8d is preferably 0.01 to 0.2, more preferably 0.02 to 0.1.

  The connecting portion 8 is configured to function as a leaf spring, and a restoring force is generated when the molded body 2 is folded at the connecting portion 8. As in the present embodiment, the molded body 2 preferably includes at least two connecting portions 8. This is because as the number of the connecting portions 8 increases, the total restoring force increases, and as a result, the force with which the molded body 2 presses the cylindrical body 5 from the inside increases.

  As shown in FIGS. 5 to 7, the connecting portion 8 is formed by compressing the parison 23 with the split molds 19 and 20 (details will be described later). For this reason, the connecting portion 8 has high accuracy and high rigidity. The bases 2a and 2b are formed by molding the parison 23 using the split molds 19 and 20, respectively. Each of the base portions 2a and 2b includes a hollow portion 2d. The base portions 2a and 2b may be foamed molded products or non-foamed molded products. However, since the base portions 2a and 2b are foam molded products, the base portions 2a and 2b are superior in light weight and sound deadening. 2a and 2b are preferably foam molded articles. The molded body 2 is preferably formed of, for example, a thermoplastic resin such as polyolefin, and examples of the polyolefin include low density polyethylene, linear low density polyethylene, high density polyethylene, polypropylene, ethylene-propylene copolymer, and mixtures thereof. Etc.

  The damping member 1 is inserted into the cylinder 5 as shown by an arrow X in FIG. 3A in a state where the damping member 1 is folded at the connecting portion 8 as shown in FIGS. 3A to 3B. As a result, a structure in which the damping member 1 is disposed in the cylinder 5 is obtained. When the damping member 1 is folded at the connecting portion 8, the outer surface shape of the damping member 1 substantially matches the inner surface shape of the cylindrical body 5. As shown in FIG. 4, when the damping member 1 is accommodated in the cylinder 5, the connecting portion 8 functions as a leaf spring, and a restoring force is generated. By this restoring force, the base portions 2a and 2b of the molded body 2 press the cylindrical body 5 from the inside, and the vibration of the cylindrical body 5 is effectively suppressed. The connecting portion 8 has an inner hinge portion 8c and outer hinge portions 8a and 8e, and a restoring force is generated in each hinge portion. Therefore, a strong restoring force is generated in the connecting portion 8, and the base portions 2a and 2b are connected to each other. The force which presses the cylinder 5 from the inside is very strong, and excellent vibration damping is achieved.

  As shown in FIG. 1, the elastic member 3 is provided on one surface of the molded body 2. The elastic member 3 may be provided so as to cover only the connecting portion 8 or may be provided so as to cover the connecting portion 8 and the base portions 2a and 2b. The part 3a which covers the connection part 8 among the elastic members 3 is between the surfaces where the connection bases 8b and 8d face when the connection part 8 is bent by the inner hinge part 8c, as shown in FIGS. 3A to 3B. Arranged and compressed and deformed by the connecting bases 8b and 8d. And base 2a, 2b presses the cylinder 5 from the inner side by the restoring force of the elastic member 3, and the vibration of the cylinder 5 is suppressed more effectively.

  Of the elastic member 3, a portion 3 b covering the base portions 2 a and 2 b is disposed between the base portions 2 a and 2 b and the cylindrical body 5 in a state where the damping member 1 is accommodated in the cylindrical body 5 as shown in FIG. 4. And functions to enhance the adhesion between the base portions 2a and 2b and the cylindrical body 5.

  As the elastic member 3, any member that generates a restoring force by being compressed can be used. The elastic member 3 can be formed of resin or rubber. It is preferable that the elastic member 3 is comprised with a nonwoven fabric. In this case, it is because the elastic member 3 is easy to generate a restoring force and it is easy to integrally mold the elastic member 3 with the molded body 2. The nonwoven fabric is preferably composed of resin fibers. The resin fiber is preferably a fiber of 5 denier or more. In this case, the rigidity of the elastic member 3 tends to be sufficiently high. The resin constituting the resin fiber preferably has a higher Picat softening point than the resin constituting the molded body 2. In this case, even in an environment where the vibration damping member 1 is exposed to a high temperature, the force with which the elastic member 3 presses the base portions 2a and 2b against the cylindrical body 5 is maintained for a long time. Examples of the resin constituting the resin fiber include PET and polyamide.

  Thus, in this embodiment, the bases 2a and 2b strongly press the cylinder 5 from the inside by the restoring force of the connecting portion 8 and the restoring force of the elastic member 3, and vibration of the cylinder 5 is effectively suppressed. . The elastic member 3 can be omitted, and in this case, the base portions 2a and 2b press the cylindrical body 5 from the inside by the restoring force of the connecting portion 8.

2. Configuration of Molding Machine 6 With reference to FIG. 5, a molding machine 6 that can be used for carrying out a method for manufacturing a vibration damping member according to an embodiment of the present invention will be described. The molding machine 6 includes a resin supply device 7, a head 18, and divided molds 19 and 20. The resin supply device 7 includes a hopper 12, an extruder 13, an injector 16, and an accumulator 17. The extruder 13 and the accumulator 17 are connected via a connecting pipe 25. The accumulator 17 and the head 18 are connected via a connecting pipe 27.
Hereinafter, each configuration will be described in detail.

<Hopper 12, Extruder 13>
The hopper 12 is used for charging the raw resin 11 into the cylinder 13 a of the extruder 13. Although the form of the raw material resin 11 is not specifically limited, Usually, it is a pellet form. The raw material resin 11 is, for example, a thermoplastic resin such as polyolefin, and examples of the polyolefin include low density polyethylene, linear low density polyethylene, high density polyethylene, polypropylene, ethylene-propylene copolymer, and a mixture thereof. The raw material resin 11 is poured into the cylinder 13a from the hopper 12 and then melted by being heated in the cylinder 13a to become a molten resin. Moreover, it is conveyed toward the front-end | tip of the cylinder 13a by rotation of the screw arrange | positioned in the cylinder 13a. A screw is arrange | positioned in the cylinder 13a and conveys molten resin by kneading | mixing by the rotation. A gear device is provided at the base end of the screw, and the screw is driven to rotate by the gear device. The number of screws arranged in the cylinder 13a may be one or two or more.

<Injector 16>
The cylinder 13a is provided with an injector 16 for injecting a foaming agent into the cylinder 13a. When the raw material resin 11 is not foamed, the injector 16 can be omitted. Examples of the foaming agent injected from the injector 16 include physical foaming agents, chemical foaming agents, and mixtures thereof, but physical foaming agents are preferred. As physical foaming agents, inorganic physical foaming agents such as air, carbon dioxide, nitrogen gas, and water, and organic physical foaming agents such as butane, pentane, hexane, dichloromethane, dichloroethane, and their supercritical fluids are used. be able to. As the supercritical fluid, carbon dioxide, nitrogen or the like is preferably used. If nitrogen, the critical temperature is 149.1 ° C. and the critical pressure is 3.4 MPa or more. If carbon dioxide, the critical temperature is 31 ° C., the critical pressure. It is obtained by setting it to 7.4 MPa or more. Examples of the chemical foaming agent include those that generate carbon dioxide by a chemical reaction between an acid (eg, citric acid or a salt thereof) and a base (eg, sodium bicarbonate). The chemical foaming agent may be supplied from the hopper 12 instead of being injected from the injector 16.

<Accumulator 17, head 18>
The molten resin 11a with or without a blowing agent added is pushed out from the resin extrusion port of the cylinder 13a and injected into the accumulator 17 through the connecting pipe 25. The accumulator 17 includes a cylinder 17a and a piston 17b that can slide inside the cylinder 17a, and the molten resin 11a can be stored in the cylinder 17a. Then, by moving the piston 17b after a predetermined amount of the molten resin 11a is stored in the cylinder 17a, the molten resin 11a is pushed out from the die slit provided in the head 18 through the connecting pipe 27, and the parison 23 is dropped. Form. The shape of the parison 23 is not particularly limited, and may be a cylindrical shape or a sheet shape.

<Split molds 19, 20>
The parison 23 is guided between the pair of split molds 19 and 20. A molded body is obtained by molding the parison 23 using the divided dies 19 and 20. The molding method using the split molds 19 and 20 is not particularly limited, and may be blow molding in which air is blown into the cavities of the split molds 19 and 20. Vacuum forming in which the inside of the cavity is decompressed from the inner surface of the cavity to form the parison 23 may be used, or a combination thereof may be used. When the molten resin contains a foaming agent, the parison 23 becomes a foamed parison, and the molded body becomes a foamed molded body.

3. Method for Manufacturing Damping Member 1 Damping member 1 can be formed by a method including a parison formation step, a molding step, and a post-treatment step. Hereinafter, each step will be described in detail.

<Parison formation process>
In the parison forming step, as shown in FIGS. 5 to 6, the molten resin is pushed out from the head and dropped to form the parison 23, and the parison 23 is disposed between the divided molds 19 and 20. The split mold 19 includes a cavity 19a surrounded by a pinch-off portion 19b. The split mold 20 includes a cavity 20a surrounded by a pinch-off portion 20b.

  Between the split mold 20 and the parison 23, an elastic member sheet 3s constituting the elastic member 3 is suspended. When the elastic member 3 is comprised with a nonwoven fabric, the elastic member sheet 3s is a nonwoven fabric sheet.

<Molding process>
In the molding process, as shown in FIG. 7, the molds 2 are formed by clamping the divided dies 19 and 20 and molding the parison 23. The molded body 2 is formed in a space surrounded by the cavities 19a and 20a. At this time, the parison 23 is compressed by the split molds 19 and 20 at the portion corresponding to the connecting portion 8 to form the connecting portion 8. Further, the elastic member sheet 3 s is integrally formed with the molded body 2 by being sandwiched between the parison 23 and the split mold 20. When the thickness of the parison 23 is T, the ratio of the thickness of the coupling bases 8b and 8d to the thickness T is preferably 0.2 to 1.4, and more preferably 0.4 to 1.0. The ratio of the thickness of the hinge portions 8a, 8c, 8e to the thickness T is preferably 0.02 to 0.28, and more preferably 0.04 to 0.14.

<Post-processing process>
In the post-processing step, the molded body 2 with the burr 23b formed as shown in FIG. 7 is taken out from the split molds 19 and 20, and the burr 23b is removed. Thereby, the damping member 1 having the configuration shown in FIG. 1 is obtained.

1: Damping member 2: Molded body 2a: First base 2b: Second base 2d: Hollow part 3: Elastic member 3a: Part 3b: Part 3s: Elastic member sheet 5: Cylindrical body 6: Molding machine 7: Resin supply Device 8: Connecting portion 8a: First outer hinge portion 8b: First connecting base 8c: Inner hinge portion 8d: Second connecting base 8e: Second outer hinge portion 11: Raw resin 11a: Molten resin 12: Hopper 13: Extrusion Machine 13a: Cylinder 16: Injector 17: Accumulator 17a: Cylinder 17b: Piston 18: Head 19: Split mold 19a: Cavity 19b: Pinch off part 20: Split mold 20a: Cavity 20b: Pinch off part 23: Parison 23b: Burr 25 : Connection pipe 27: Connection pipe

Claims (9)

A damping member inserted into the cylinder,
The vibration damping member includes a molded body,
The molded body includes a plurality of base portions and a connecting portion that connects two adjacent base portions of the plurality of base portions,
The said connection part is a damping member comprised so that folding was possible between the said two adjacent base parts. The connecting portion includes first and second outer hinge portions and an inner hinge portion provided therebetween,
2. The vibration damping member according to claim 1, wherein the inner hinge portion is configured to be bent in a direction opposite to the first and second outer hinge portions. The connection part includes a first connection base between the first outer hinge part and the inner hinge part, and a second connection base between the second outer hinge part and the inner hinge part,
The said damping member is a damping member of Claim 2 provided with an elastic member between the surfaces where a 1st and 2nd connection base opposes when the said connection part is bent by the said inner side hinge part.   The vibration damping member according to claim 3, wherein the elastic member is made of a nonwoven fabric.   The damping member according to claim 3 or 4, wherein the elastic member is integrally formed with the molded body.   The said molded object is a damping member as described in any one of Claims 1-5 which has a hollow part.   The damping member according to any one of claims 1 to 6, wherein the molded body is a foam molded body. A method for manufacturing a vibration damping member according to any one of claims 1 to 7,
A parison forming step of extruding the molten resin to form a parison and placing it between a pair of split molds;
Including a molding step of forming the molded body by molding the parison by performing clamping of the split mold,
The method for manufacturing a vibration damping member, wherein the connecting portion is formed on the molded body by compressing the parison with the divided mold when the divided mold is clamped. A method of manufacturing a structure comprising a step of inserting a damping member into a cylinder,
The damping member is the damping member according to any one of claims 1 to 7,
The manufacturing method of a structure, wherein the damping member is inserted into the cylindrical body in a state where the damping member is folded at the connecting portion.