Vehicle and method for manufacturing fender liner

Abstract

This fender liner is disposed in a curved shape along the outer circumference of a tire of a vehicle. The fender liner comprises a first foam layer, and a second foam layer. The first foam layer is formed of a first foam material. The second foam layer is formed of a second foam material with a composition different from the first foam material. The first foam layer and the second foam layer are arranged in the circumferential direction of the tire.

Description

[Technical Field]

[0001] The present disclosure provides: vehicle and Fender liner Manufacturing method By law Regarding. [Background technology]

[0002] Fender liners are curved and positioned around the outer periphery of a vehicle's tires to prevent pebbles and other foreign objects kicked up while the vehicle is running from colliding with the vehicle body. Furthermore, fender liners contain nonwoven fabrics and the like, and absorb vehicle running noise and the sound of foreign objects colliding with the vehicle (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2015-17339 Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors of the present invention investigated the relationship between the frequency and magnitude of sound waves observed near the fender liner while the vehicle was running, and found that the characteristics of the sound waves differ in the circumferential direction of the tire.

[0005] One aspect of the present disclosure provides a technique for reducing noise intensity over a wide frequency range using fender liners. [Means for solving the problem]

[0006] A fender liner according to one embodiment of the present disclosure is arranged in a curved shape along the outer periphery of a vehicle tire. The fender liner includes a first foam layer and a second foam layer. The first foam layer is formed of a first foam. The second foam layer is formed of a second foam having a different composition from the first foam. The first foam layer and the second foam layer are aligned in the circumferential direction of the tire. [Effects of the Invention]

[0007] According to one aspect of the present disclosure, the sound absorption characteristics of the fender liner can be changed in the circumferential direction of the tire, and the fender liner can be used to reduce noise intensity over a wide frequency band. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing the undercarriage of a vehicle on which a fender liner according to one embodiment is mounted. [Figure 2] FIG. 2 is a flowchart illustrating a method for manufacturing a fender liner according to one embodiment. [Figure 3] FIG. 3 is a cross-sectional view showing an example of S102 in FIG. [Figure 4] FIG. 4 is a cross-sectional view showing an example of S105 in FIG. [Figure 5] FIG. 5 is a cross-sectional view showing an example of S106 in FIG. [Figure 6] FIG. 6 is a diagram showing the sound absorption characteristics of the foam A and foam B used in Examples 1 to 3. As shown in FIG. [Figure 7] FIG. 7 is a diagram showing the infrared absorption spectra of Foam A and Foam B used in Examples 1 to 3. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding components are denoted by the same reference numerals, and their description may be omitted. Furthermore, in the specification, a numerical range indicated by "to" means that the numerical values before and after the range are included as the lower and upper limits.

[0010] First, a fender liner 1 according to one embodiment will be described with reference to Fig. 1. In Fig. 1, the outline arrow indicates the direction of travel of the vehicle, with the left side being the front of the vehicle and the right side being the rear of the vehicle.

[0011] The fender liner 1 is disposed inside a tire well 31. The tire well 31 is a space that houses a tire 2 of a vehicle body 3. The fender liner 1 is disposed in a curved shape along the outer periphery of the tire 2. The fender liner 1 forms a gap of a certain size between itself and the tire 2 so as not to come into contact with the tire 2.

[0012] Fender liner 1 prevents foreign objects, such as pebbles, kicked up while the vehicle is running from colliding with vehicle body 3. Fender liner 1 also absorbs vehicle running noise and the sound of foreign objects colliding with the vehicle. Fender liner 1 is attached to vehicle body 3 using, for example, pins and washers.

[0013] The inventors of the present application investigated the relationship between the frequency and magnitude of sound waves observed near the fender liner 1 while the vehicle was running and found that the characteristics of the sound waves differed in the circumferential direction of the tire 2. As will be explained in more detail in the Examples section, when the frequency of the sound waves was 1250 Hz or less, the sound waves (noise) were louder in front of the top end of the tire 2 than behind it. On the other hand, when the frequency of the sound waves exceeded 1250 Hz, the sound was louder in the rear of the top end of the tire 2 than in front. In this way, the inventors of the present application found that the location where the sound volume was loudest changed in the circumferential direction of the tire 2 depending on the frequency of the sound waves.

[0014] The characteristics of the sound waves observed near the fender liner 1 can change depending on the shape and dimensions of the fender liner 1, as well as the rotation speed and tread pattern of the tire 2. However, even if the shape or dimensions of the fender liner 1, or the rotation speed or tread pattern of the tire 2, changes, it is believed that the tendency for the location where the sound volume is loudest to change circumferentially around the tire 2 according to the frequency of the sound waves will not change.

[0015] As shown in Figure 1, the fender liner 1 includes at least a first foam layer 11 and a second foam layer 12. The first foam layer 11 is formed from a first foam, while the second foam layer 12 is formed from a second foam having a different composition from the first foam.

[0016] The difference between the composition of the first foam and the composition of the second foam can be confirmed by the difference between the infrared absorption spectrum of the first foam and the infrared absorption spectrum of the second foam. The infrared absorption spectrum is measured in accordance with Japanese Industrial Standard JIS K0117:2017 by the attenuated total reflection method (ATR method). The difference between the infrared absorption spectrum of the first foam and the infrared absorption spectrum of the second foam can be confirmed by, for example, observing different peaks or by observing a difference in the resolution of 4 cm. -1 When measured at 20 cm, the wave number of the peak is 5 times the resolution. -1 Furthermore, even when the wave numbers of the peaks are the same, if the ratio of the intensity of one peak to the intensity of another peak is different, it can be determined that the compositions are different.

[0017] According to this embodiment, the first foam layer 11 and the second foam layer 12, which have different compositions, are aligned in the circumferential direction of the vehicle tire 2. Therefore, the sound absorption characteristics of the fender liner 1 can be changed in the circumferential direction of the tire 2, and the fender liner 1 can be used to reduce noise levels over a wide frequency band.

[0018] For example, the first foam layer 11 has a lower sound absorption coefficient peak frequency and is located closer to the front of the vehicle than the second foam layer 12. When low-frequency sounds are louder in the area forward of the top end of the tire 2 than in the area behind, the fender liner 1 can be used to reduce the noise level over a wide frequency band.

[0019] The first foam layer 11 may have a higher peak frequency of sound absorption coefficient and may be located closer to the front of the vehicle than the second foam layer 12. When high-frequency sounds are louder in the area forward of the top end of the tire 2 than in the area rearward, the fender liner 1 can be used to reduce the noise level over a wide frequency band.

[0020] Although not shown, the fender liner 1 may include a third foam layer between the first foam layer 11 and the second foam layer 12 along the circumferential direction of the tire 2. The third foam layer is formed of a third foam having an intermediate composition between the first foam and the second foam. The fact that the composition of the third foam is intermediate between the compositions of the first and second foams can be confirmed by the fact that the infrared absorption spectrum of the third foam is intermediate between the infrared absorption spectrum of the first foam and the infrared absorption spectrum of the second foam.

[0021] As will be described later, the fender liner 1 is obtained by injecting a first resin composition that forms a first foam body and a second resin composition that forms a second foam body into the internal space 56 of a molding die 5 shown in Figure 3, etc., and foaming and solidifying the first and second resin compositions. A third foam layer is formed where the first and second resin compositions join.

[0022] The presence of the third foam layer means that the first foam layer 11 and the second foam layer 12 are simultaneously molded in the internal space 56 of the mold 5. In this case, the number of steps can be reduced compared to when the first foam layer 11 and the second foam layer 12 are molded separately and then joined together with an adhesive or the like, thereby reducing the manufacturing costs of the fender liner 1.

[0023] Next, referring back to FIG. 1, the first foamed layer 11 and the second foamed layer 12 that constitute the fender liner 1 will be described.

[0024] First, the first foam layer 11 will be described. Unlike nonwoven fabric, the first foam layer 11 has a three-dimensional network structure. The first foam layer 11 has many air bubbles inside. The many air bubbles are interconnected, and sound waves propagate through them. At this time, the air inside the first foam layer 11 vibrates. Friction occurs between the three-dimensional network structure of the first foam layer 11 and the air, and the energy of the sound waves is converted into heat energy. As a result, sound is absorbed. This can reduce the noise level outside the vehicle and the noise level inside the vehicle.

[0025] While nonwoven fabric contains two-dimensionally oriented fibers, the first foam layer 11 has a three-dimensionally laid network skeleton. Therefore, the first foam layer 11 can improve the sound absorption coefficient compared to nonwoven fabric. Furthermore, the first foam layer 11 has a three-dimensionally laid network skeleton that is continuously connected, which can improve the shape retention.

[0026] The first foam layer 11 is, for example, a polyurethane foam. The polyurethane foam is a so-called polyurethane foam, and is obtained by foaming and solidifying a first resin composition containing polyisocyanate, polyol, a catalyst, and a foaming agent. The foaming agent contains water. The foaming agent may also contain chlorine. Details of the first resin composition will be described later.

[0027] In this embodiment, the first foam layer 11 is a polyurethane foam, but it may be a polyacrylic, melamine, rubber, polyolefin, or polyimide foam. These materials containing polyurethane are lightweight and have excellent shape retention.

[0028] The thickness of the first foam layer 11 is, for example, 3 mm to 30 mm, preferably 3 mm to 20 mm, from the viewpoint of achieving both light weight and sound absorption properties.

[0029] The density of the first foam layer 11 is set to, for example, 20 kg / m from the viewpoint of achieving both light weight and sound absorption properties. 3 ~140kg / m 3 The density of the first foamed layer 11 is the so-called bulk density, and is measured in accordance with JIS K7222:2005 "Foamed plastics and rubber - Determination of apparent density." The density of the first foamed layer 11 is preferably 30 kg / m 3 ~130kg / m 3 , more preferably 55 kg / m 3 ~120kg / m 3 is.

[0030] The sound absorption coefficient of the first foam layer 11 is, for example, 0.4 to 1.0. The sound absorption coefficient of the first foam layer 11 is measured by cutting out a test piece with a thickness of 10 mm, applying a 1000 Hz sound wave perpendicularly to the test piece, and following JIS A1405-2:2007 "Measurement of sound absorption coefficient and impedance using an acoustic tube." The sound absorption coefficient of the first foam layer 11 is preferably 0.5 to 1.0. A sound absorption coefficient of 1.0 means that no sound is reflected at all.

[0031] Next, the second foam layer 12 will be described. Like the first foam layer 11, the second foam layer 12 has a three-dimensionally laid out network skeleton. Therefore, the second foam layer 12 can improve the sound absorption coefficient compared to nonwoven fabric. Furthermore, the second foam layer 12 has a three-dimensionally laid out network skeleton that is continuously connected, which can improve shape retention.

[0032] The second foam layer 12 is, for example, a polyurethane foam. The polyurethane foam is a so-called polyurethane foam, and is obtained by foaming and solidifying a second resin composition containing polyisocyanate, polyol, a catalyst, and a blowing agent. The blowing agent contains water. The blowing agent may contain chlorine. The composition of the second resin composition is different from the composition of the first resin composition. Details of the second resin composition will be described later.

[0033] In this embodiment, the second foam layer 12 is a polyurethane foam, but it may be a polyacrylic, melamine, rubber, polyolefin, or polyimide foam. These materials containing polyurethane are lightweight and have excellent shape retention.

[0034] The thickness of the second foam layer 12 is, for example, 3 mm to 30 mm, preferably 3 mm to 20 mm, from the viewpoint of achieving both lightness and sound absorption properties.

[0035] The density of the second foam layer 12 is set to, for example, 20 kg / m from the viewpoint of achieving both light weight and sound absorption properties. 3 ~140kg / m 3The density of the second foamed layer 12 is the so-called bulk density, and is measured in accordance with JIS K7222:2005 "Foamed plastics and rubber - Determination of apparent density." The density of the second foamed layer 12 is preferably 30 kg / m 3 ~130kg / m 3 , more preferably 55 kg / m 3 ~120kg / m 3 is.

[0036] The sound absorption coefficient of the second foam layer 12 is, for example, 0.4 to 1.0. The sound absorption coefficient of the second foam layer 12 is measured by cutting out a test piece with a thickness of 10 mm, applying a 1000 Hz sound wave perpendicularly to the test piece, and following JIS A1405-2:2007 "Measurement of sound absorption coefficient and impedance using an acoustic tube." The sound absorption coefficient of the second foam layer 12 is preferably 0.5 to 1.0.

[0037] The difference in frequency between the sound absorption peak of the second foam layer 12 and the sound absorption peak of the first foam layer 11 is, for example, 1 / 3 octave or more, preferably 2 / 3 octave or more, more preferably 1 octave or more. The difference is, for example, 7 / 3 octave or less, preferably 2 octaves or less.

[0038] Next, a method for manufacturing a fender liner according to one embodiment will be described with reference to Fig. 2. The method for manufacturing a fender liner 1 includes, for example, steps S101 to S107 shown in Fig. 2. In this embodiment, a molding die 5 shown in Figs. 3 to 5 is used. From the viewpoint of temperature controllability, the molding die 5 is a metal mold. Note that the molding die 5 may be a sand mold, a wooden mold, or a resin mold.

[0039] First, in step S101, the temperature of casting mold 5 is adjusted. Temperature adjustment of casting mold 5 continues in subsequent steps. Temperature adjustment (step S101) only needs to be started before injection (step S103). It is sufficient for the temperature of casting mold 5 to stabilize before injection (step S103).

[0040] The temperature of casting mold 5 is adjusted to 50° C. to 70° C. A flow path through which a temperature control medium such as water flows is formed inside casting mold 5. An electric heater or the like may be embedded inside casting mold 5.

[0041] If the temperature of the mold 5 is 50°C or higher, the polymerization reaction and the foaming reaction can proceed. If the temperature of the mold 5 is 70°C or lower, the reaction rates can be appropriately suppressed, preventing solidification from completing before the resin has permeated the entire interior space 56 of the mold 5, and preventing the occurrence of incomplete filling, or so-called short circuits.

[0042] The temperature distribution of the molding die 5 may be uniform or non-uniform. In the latter case, the polymerization reaction and foaming reaction of the first resin composition and the second resin composition can be adjusted by the temperature difference.

[0043] Next, in step S102, as shown in FIG. 3, the lower mold 51 and upper mold 52 that make up the molding die 5 are closed. Specifically, the molding die 5 is closed by moving the upper mold 52 from the mold open position (see FIG. 5) to the mold closed position (see FIG. 3). When the mold closing is complete, an internal space 56 is formed between the lower mold 51 and the upper mold 52. The internal space 56 is the space in which the fender liner 1 is molded.

[0044] The forming die 5 is divided into a lower die 51 and an upper die 52. The upper die 52 is disposed above the lower die 51. The upper die 52 is further divided into a plurality of split dies 53 to 55. The lower die 51 and the upper die 52 are also split dies of the forming die 5. The boundary between these split dies is called the parting line PL of the forming die 5.

[0045] The lower mold 51 is a fixed mold. The lower mold 51 has an upper surface 511 that is convex upward, and has a recess 512 on the upper surface 511. The recess 512 is formed at a certain depth from the upper surface 511 of the lower mold 51.

[0046] On the other hand, the upper mold 52 is a movable mold. The upper mold 52 has a lower surface 521 that is convex upward. The lower surface 521 of the upper mold 52 contacts the upper surface 511 of the lower mold 51. Although not shown, a second recess may be formed in the lower surface of the upper mold 52, and the resin composition may be foamed inside the second recess. The thickness of at least one of the first foam layer 11 and the second foam layer 12 can be partially increased. The number of second recesses is one or more.

[0047] The upper mold 52 has an upwardly convex arch shape and is divided into three split molds 53 to 55 in the circumferential direction. The split molds 53 and 55 at both ends are connected to the lower mold 51 by different hinges H1 and H2. The split mold 53 at one end rotates around the hinge H1 between a mold closed position (see FIG. 3) and a mold open position (see FIG. 5). The split mold 55 at the other end rotates around the hinge H2 between a mold closed position (see FIG. 3) and a mold open position (see FIG. 5).

[0048] The middle split mold 54 is connected to one of the two split molds 53, 55 at both ends (for example, split mold 53) by a hinge H3. The middle split mold 54 rotates around the hinge H3 and rotates between a mold closed position (see FIG. 3) and a mold open position (see FIG. 5) relative to the split mold 53 at one end.

[0049] In this embodiment, the upper mold 52 is divided into three split molds 53 to 55, but it may be divided into two split molds, or into four or more split molds. The number of split molds into which the upper mold 52 is divided is not particularly limited.

[0050] As described above, the upper mold 52 is divided into a plurality of split molds 53 to 55. The split molds 53 to 55 can be moved individually, and the range of movement of the upper mold 52 can be made smaller than when the entire upper mold 52 is moved collectively.

[0051] Next, in step S103, the first resin composition is injected into the internal space 56 of the molding die 5 closed in step S102 through the first injection inlet 57, and the second resin composition is injected through the second injection inlet 58. The first injection inlet 57 and the second injection inlet 58 are spaced apart from each other in the circumferential direction of the tire 2.

[0052] The internal space 56 of the molding die 5 is arch-shaped and convex upward. The first resin composition flows down to one lower end of the arch-shaped internal space 56, and the second resin composition flows down to the other lower end of the arch-shaped internal space 56.

[0053] The injection of the first resin composition and the injection of the second resin composition may be carried out simultaneously or at different times, as long as the first resin composition and the second resin composition meet in a softened state.

[0054] After the first resin composition is injected, a first plug 59 is inserted into the first injection port 57 as shown in Fig. 4, and the first plug 59 closes the first injection port 57. After the second resin composition is injected, a second plug 60 is inserted into the second injection port 58, and the second plug 60 closes the second injection port 58.

[0055] Next, in step S104, the first resin composition and the second resin composition are foamed in the internal space 56 of the molding die 5. During this process, gas is generated. The generated gas is pushed out of the internal space 56 through the parting line PL of the molding die 5 to the outside of the molding die 5. During this process, the resin composition infiltrates the parting line PL together with the gas, and when it cools and hardens, so-called flash B is formed.

[0056] In this embodiment, the parting lines PL are not positioned on the surface 1b of the fender liner 1 that faces the tire 2. As a result, no burrs B are formed on the surface 1b of the fender liner 1 that faces the tire 2. This prevents burrs B from interfering with the tire 2. Burrs B are formed on the surface 1a of the fender liner 1 that faces away from the tire 2.

[0057] Next, in step S105, as shown in Fig. 4, the foamed first resin composition and second resin composition are solidified. Solidification includes curing. Step S105 results in a fender liner 1 including a first foamed layer 11 and a second foamed layer 12. Although not shown, a third foamed layer is formed between the first foamed layer 11 and the second foamed layer 12.

[0058] The first foam layer 11 and the second foam layer 12 are connected near the upper end of the arch-shaped internal space 56 via a third foam layer (not shown). Note that by changing the injection amounts of the first resin composition and the second resin composition, it is possible to change the position of the boundary (third foam layer) between the first foam layer 11 and the second foam layer 12 in the circumferential direction of the tire 2. The molding die 5 may also be installed upside down. Even when the molding die 5 is installed upside down, the first injection port 57 and the second injection port 58 are provided above the internal space 56.

[0059] In either case, the fender liner 1 is molded to have the same shape and dimensions as the internal space 56 of the mold 5. Therefore, fender liners 1 having the same shape and dimensions can be mass-produced.

[0060] Furthermore, since the shape and dimensions of the fender liner 1 are determined by the shape and dimensions of the internal space 56 of the molding die 5, it is possible to impart a fine structure, and post-processing such as cutting or pressing is not required.

[0061] Furthermore, compared to molding the first foam layer 11 and the second foam layer 12 that make up the fender liner 1 separately and joining them with an adhesive or the like, the number of steps can be reduced, thereby reducing the manufacturing cost of the fender liner 1.

[0062] Next, in step S106, lower mold 51 and upper mold 52 are opened as shown in Fig. 5. Specifically, upper mold 52 is moved from the mold closed position (see Fig. 3) to the mold open position (see Fig. 5), thereby opening forming mold 5.

[0063] Finally, in step S107, the fender liner 1 is removed from the mold 5 after the mold is opened. The fender liner 1 may include a tapered surface 1c that tapers toward the tire 2 (toward the tire 2 radially inward). The tapered surface 1c is inclined relative to the radial direction of the tire 2. The tapered surface 1c makes it easier to remove the fender liner 1 from the lower mold 51 and reduces damage during mold release.

[0064] If the fender liner 1 has excellent flexibility, the tapered surface 1c is not necessary. In this case, the fender liner 1 is released from the mold while being deformed.

[0065] The method for manufacturing fender liner 1 may include steps other than steps S101 to S107 shown in Fig. 2. For example, the method for manufacturing fender liner 1 may include a step of forming a water-repellent layer on surface 1b of fender liner 1 that faces tire 2 after removing fender liner 1 from mold 5.

[0066] The water-repellent layer makes it easier for water droplets scattered by the tire 2 to slide. This prevents water droplets from remaining on the surface, and prevents ice from forming. If ice does not form, damage caused by the ice peeling off will not occur. The water-repellent layer is formed from a coating agent, such as a fluorine-based, silicone-based, or hydrocarbon-based coating agent with low polarity, such as polyethylene or polypropylene.

[0067] The water-repellent layer may be breathable. Compared to a water-repellent layer that is not breathable, sound waves, such as the running noise of the tire 2, can easily penetrate into the fender liner 1. This reduces the reflection of sound waves. A breathable water-repellent layer is formed by a spray coating method using, for example, a fluorine-based, silicone-based, or hydrocarbon-based coating agent. The hydrocarbon-based coating agent preferably contains polyethylene, polypropylene, or other agents with low polarity.

[0068] Next, the first resin composition, which is the raw material of the first foam, will be described. When the first foam is a polyurethane foam, the first resin composition contains a polyisocyanate, a polyol, a catalyst, and a blowing agent. The first resin composition may further contain additives. The first resin composition is usually prepared by mixing a system liquid containing raw materials other than the polyisocyanate with the polyisocyanate.

[0069] Examples of polyisocyanates include, but are not limited to, toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymethylene polyphenylisocyanate (commonly known as crude MDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), and hexamethylene diisocyanate (HMDI), as well as prepolymer-modified, isocyanurate-modified, urea-modified, and carbodiimide-modified versions of these polyisocyanates. TDI may be either 2,4-TDI or 2,6-TDI, or a mixture thereof. MDI may be any of 2,2'-MDI, 2,4'-MDI, and 4,4'-MDI, or a mixture of two or three of these.

[0070] Examples of the polyol include polyoxyalkylene polyol and polyester polyol.

[0071] Water can be used as a blowing agent, but is not limited to this. A blowing agent other than water is preferably an inert compound with a low boiling point. Examples of such inert compounds include inert gases and saturated hydrocarbons with a boiling point of 70°C or less, a carbon number of 8 or less, and in which hydrogen atoms bonded to carbon atoms may be substituted with halogen atoms. The halogen atoms are, for example, chlorine atoms or fluorine atoms. Examples of saturated hydrocarbons include but are not limited to butane, pentane, hexane, dichloromethane (methylene chloride), trichloroethane, and various fluorocarbon compounds. Furthermore, one type of blowing agent may be used alone, or two or more types may be used in combination.

[0072] The catalyst is at least one selected from the group consisting of amine catalysts and tin catalysts. One catalyst may be used alone, or two or more catalysts may be used in combination. Examples of the amine catalyst include, but are not limited to, triethylenediamine, bis(2-dimethylaminoethyl)ether, N,N,N',N'-tetramethylhexamethylenediamine, N,N-dimethylaminoethoxyethoxyethanol, N,N-dimethylamino-6-hexanol, N,N-dimethylaminoethoxyethanol, a compound in which two moles of ethylene oxide are added to N,N-dimethylaminoethoxyethanol, and 5-(N,N-dimethyl)amino-3-methyl-1-pentanol. Examples of the tin-based catalyst include, but are not limited to, tin 2-ethylhexanoate, di-n-butyltin oxide, di-n-butyltin dilaurate, di-n-butyltin diacetate, di-n-octyltin oxide, di-n-octyltin dilaurate, monobutyltin trichloride, di-n-butyltin dialkyl mercaptan, and di-n-octyltin dialkyl mercaptan.

[0073] The additive may contain a foam stabilizer. Examples of the foam stabilizer include, but are not limited to, silicone-based foam stabilizers and fluorine-containing compound-based foam stabilizers. One type of foam stabilizer may be used alone, or two or more types may be used in combination.

[0074] A crosslinking agent may be included as an additive. The crosslinking agent may be a compound having two or more active hydrogen-containing groups selected from a hydroxyl group, a primary amino group, and a secondary amino group. Examples of crosslinking agents include ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, pentaerythritol, diglycerin, monoethanolamine, diethanolamine, triethanolamine, bisphenol A, ethylenediamine, 3,5-diethyl-2,4-diaminotoluene, 3,5-diethyl-2,6-diaminotoluene, 2-chloro-p-phenylenediamine, 3, Examples of crosslinking agents include, but are not limited to, 5-bis(methylthio)-2,4-diaminotoluene, 3,5-bis(methylthio)-2,6-diaminotoluene, 1-trifluoromethyl-3,5-diaminobenzene, 1-trifluoromethyl-4-chloro-3,5-diaminobenzene, 2,4-toluenediamine, 2,6-toluenediamine, bis(3,5-dimethyl-4-aminophenyl)methane, 4,4'-diaminodiphenylmethane, m-xylylenediamine, 1,4-diaminohexane, 1,3-bis(aminomethyl)cyclohexane, and isophoronediamine. Furthermore, the above-mentioned polyoxyalkylene polyols having a molecular weight / hydroxyl group number of less than 500 can also be used as crosslinking agents. One type of crosslinking agent may be used alone, or two or more types may be used in combination.

[0075] Examples of additives other than those mentioned above include emulsifiers, antioxidants, anti-aging agents such as ultraviolet absorbers, fillers such as calcium carbonate or barium sulfate, plasticizers, colorants, flame retardants, anti-fungal agents, and foam breakers, and various other known additives and auxiliaries. However, the present invention is not limited to these, and additives conventionally used in polyurethane foams can also be used.

[0076] Next, the second resin composition, which is the raw material of the second foam, will be described. When the second foam is a polyurethane foam, the second resin composition contains polyisocyanate, polyol, catalyst, and blowing agent, similar to the first resin composition. The second resin composition may further contain additives. The second resin composition is prepared by mixing the same materials as the first resin composition but in a different mixing ratio, or is prepared from materials different from those of the first resin composition. [Example]

[0077] Experimental data will be explained below. Examples 1 and 2 below are comparative examples, and Example 3 is an embodiment. First, Foam A and Foam B used in Examples 1 to 3 will be explained. Resin composition A, which is the material for Foam A, was prepared by placing 109.3 parts by mass of system liquid A and 39.3 parts by mass of polyisocyanate (a mixture of TDI and MDI, manufactured by Tosoh Corporation, product name: Coronate 1021) in a container and mixing them in a high-speed mixer at room temperature. System liquid A contained 60 parts by mass of polyoxyalkylene polyol 1 (manufactured by AGC, trade name: EXCENOL 820), 40 parts by mass of polyoxyalkylene polyol 2 (manufactured by AGC, trade name: EXCENOL 923), 3 parts by mass of water as a blowing agent, 0.3 parts by mass of catalyst 1 (manufactured by Tosoh Corporation, trade name: TEDA L-33), 0.05 parts by mass of catalyst 2 (manufactured by Tosoh Corporation, trade name: TOYOCAT-ET), 3 parts by mass of foam stabilizer 1 (manufactured by Evonik, trade name: Tegostab B8737LF2), and 3 parts by mass of crosslinker 1 (manufactured by AGC, trade name: EXCENOL 555).

[0078] Resin composition B, the material for foam B, was prepared by placing 142.4 parts by weight of system liquid B and 42.4 parts by weight of polyisocyanate (a mixture of TDI and MDI, manufactured by Tosoh Corporation, trade name: Coronate 1021) in a container and mixing them in a high-speed mixer at room temperature. System liquid B contained 60 parts by weight of the polyoxyalkylene polyol 1, 40 parts by weight of the polyoxyalkylene polyol 2, 30 parts by weight of polyoxyalkylene polyol 3 (manufactured by Fujifilm Wako Pure Chemical Industries, trade name: Polytetramethylene Oxide 2,000), 3 parts by weight of water as a blowing agent, 0.3 parts by weight of catalyst 1, 0.05 parts by weight of catalyst 2, 3 parts by weight of foam stabilizer 1, 3 parts by weight of colorant (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., trade name: FTR5570), and 3 parts by weight of crosslinker 1.

[0079] Resin composition A was injected, foamed, and solidified to prepare a test piece consisting only of foam A, and the frequency dependence of the normal incident sound absorption coefficient of the test piece was measured. Resin composition B was injected, foamed, and solidified to prepare a test piece consisting only of foam B, and the frequency dependence of the normal incident sound absorption coefficient of the test piece was measured. These measurements were performed using a WinZac MTX manufactured by Nihon Onkyo Engineering Co., Ltd. The measurement results are shown in Figure 6. As shown in Figure 6, Foam A had a lower peak frequency of the sound absorption coefficient than Foam B. The difference in frequency between the sound absorption peak of Foam A and the sound absorption peak of Foam B was 1 / 3 octave.

[0080] Figure 7 shows the infrared absorption spectra of Foam A and Foam B. The measurements were performed using an infrared absorption spectrometer (FT-IR, Nicolet iZ10 manufactured by Thermo Fisher Scientific Co., Ltd.). The absorbance was measured at 800 cm -1 ~4000cm -1 The absorbance was normalized to the maximum value measured at a wavenumber of 2700 cm. -1 ~3100cm -1 Only the range of wavenumber 2700 cm is shown. -1 ~3100cm -1 Infrared absorption due to the C–H bond of hydrocarbons is observed in the range. The number of scans was 32, and the resolution was 4 cm.-1 It was decided.

[0081] In the infrared absorption spectra of Foam A and Foam B shown in FIG. 7, only Foam B exhibited a peak at 2800 cm -1 A peak was observed around 2870cm, which indicates that the composition is different. -1 Nearby peaks and 2970cm -1 The different peak intensity ratios in the vicinity also indicate that they have different compositions.

[0082] In Examples 1 to 3, as shown in Table 1, foam A and foam B were used to create an analytical model of a fender liner.

[0083] [Table 1] As shown in Table 1, the analytical model of the fender liner of Example 1 was created using only foam A. The analytical model of the fender liner of Example 2 was created using only foam B. The analytical model of the fender liner of Example 3 was created with the front (the portion forward of the top end of the tire) made of foam A and the rear (the portion rearward of the top end of the tire) made of foam B.

[0084] In Examples 1 to 3, the relationship between the frequency and magnitude of sound waves observed near the fender liner while the vehicle was running was analyzed using the finite element method. The analysis conditions were as follows: Acoustic boundary conditions: The ground and tire surface were set as perfect reflecting boundaries, and the fender liner was set as an admittance boundary based on the normal incidence sound absorption coefficient. Air: speed of sound is set to 340 m / s and density is 1.225 kg / m 3 was set to. Tires: Diameter 636mm, width 226mm. No tread pattern. Input sound source: Point sound sources were set at the front and rear ends of the tire's contact area. The sound volume of each of the two point sound sources was set based on the noise level measured with surrounding microphones when the tire was rotated at a constant speed in the laboratory. The tire rotation speed was equivalent to a vehicle speed of 50 km / h. -Fender liner shape: Standard shape.

[0085] The analytical results of Example 1 are shown in Table 2, the analytical results of Example 2 are shown in Table 3, and the analytical results of Example 3 are shown in Table 4. In Tables 2 to 4, L max _f is the maximum noise level observed at the front of the fender liner. max _r is the maximum noise level observed at the rear of the fender liner. L max is the maximum noise level observed across the entire fender liner.

[0086] [Table 2]

[0087] [Table 3]

[0088] [Table 4] As is clear from Tables 2 to 4, when the sound wave frequency was 1250 Hz or less, the sound waves (noise) were louder at the front of the fender liner than at the rear of the fender liner. On the other hand, when the sound wave frequency exceeded 1250 Hz, the sound was louder at the rear of the fender liner than at the front of the fender liner.

[0089] The results of Tables 2 to 4 are summarized in Table 5.

[0090] [Table 5] In Table 5, L0 max is the maximum noise level observed throughout the entire fender liner when the fender liner is made of a dense resin sheet, specifically a polypropylene resin sheet. max was analyzed for each sound wave frequency.

[0091] As is clear from Table 5, in Example 3, unlike Examples 1 and 2, the fender liner was constructed by combining Foam A and Foam B, which had different compositions, and therefore noise intensity could be reduced over a wide frequency band.

[0092] The above relates to the present disclosure. vehicle and Fender liner Manufacturing method of law Embodiments, etc. However, the present disclosure is not limited to the above-described embodiments. Within the scope of the above, various changes, modifications, substitutions, additions, deletions, and combinations are possible. Naturally, these also fall within the technical scope of the present disclosure.

[0093] The first foam layer 11 and the second foam layer 12 having different compositions may be aligned in the width direction of the vehicle tire 2. When the location where the sound volume is loudest varies in the width direction of the tire 2 depending on the frequency of the sound wave, the noise volume can be reduced over a wide frequency band.

[0094] This application claims priority based on Japanese Patent Application No. 2020-194962, filed with the Japan Patent Office on November 25, 2020, the entire contents of which are incorporated herein by reference. [Explanation of symbols]

[0095] 1 fender liner 2 tires 11 First foam layer 12 Second foam layer

Claims

1. A tire; a fender liner that is curved and disposed along the outer periphery of the tire of a vehicle, The fender liner includes a first foam layer formed of a first foam material and a second foam layer formed of a second foam material having a composition different from that of the first foam material, The first foam layer and the second foam layer are aligned in the circumferential direction of the tire. The first foam layer has a lower peak frequency of sound absorption coefficient than the second foam layer and is located closer to the front of the vehicle.

2. 2. The vehicle according to claim 1, further comprising: a third foam layer formed between the first foam layer and the second foam layer along the circumferential direction of the tire, the third foam layer being formed of a third foam having an intermediate composition between the first foam layer and the second foam layer.

3. The vehicle of claim 1 or 2, wherein the first foam comprises polyurethane, polyacrylic, melamine, rubber, polyolefin, or polyimide.

4. A method for manufacturing a fender liner included in a vehicle according to any one of claims 1 to 3, comprising: Injecting a first resin composition that forms the first foam and a second resin composition that forms the second foam into an internal space of a molding die; foaming the first resin composition and the second resin composition in the internal space of the molding die; solidifying the first resin composition and the second resin composition foamed in the internal space of the molding die to form the first foamed layer and the second foamed layer.

5. The vehicle according to any one of claims 1 to 3, further comprising a water-repellent layer on a surface of the fender liner facing the tire.

6. The vehicle according to claim 5 , wherein the water-repellent layer is breathable.

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