Speaker grille manufacturing method

Abstract

To provide a method of manufacturing a speaker grille in which a skin member can be easily stuck on a grille to effectively prevent hindrance to transmission of a sound from a speaker.SOLUTION: A method of manufacturing a speaker grille 1 has a fusion step and a crimping step after the fusion step. The fusion step comprises overlaying a resin sheet 3 on the upper side of a punching grille 2 and then heating the punching grille 2 and resin sheet 3 to fuse the resin sheet 3. The crimping step comprises overlaying a synthetic resin fabric member 4 on the upper side of the fused resin sheet 3, and pressing and bonding the punching grille 2, the resin sheet 3, and the synthetic resin fabric member 4. The resin constituting the resin sheet 3 is polyamide.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The technical aspect of the present invention relates to a method for manufacturing a speaker grille that covers a speaker placed inside an automobile or the like. [Background technology]

[0002] Speaker grilles with multiple sound-transmitting holes are widely used to cover speakers placed inside automobiles and the like. Conventionally, a speaker grille of this type, in which the surface of the grille is decorated with a surface material, has been proposed in Patent Document 1 below. In this speaker grille, an adhesive is applied to the grille surface so that the surface material can be easily attached, and the surface material is adhered to the adhesive on the grille surface. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-011645 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, the conventional speaker grill described in Patent Document 1 has the problem that it cannot be easily attached because an adhesive is applied to the grill surface and the surface material is bonded to it, requiring an adhesive application process. In addition, the conventional speaker grill has the problem that the adhesive applied during the adhesive application process may block the through-holes of the grill, potentially hindering the transmission of sound from the speaker.

[0005] The present invention has been made in view of the above-mentioned points, and aims to provide a method for manufacturing a speaker grille that allows the surface material to be easily attached to the grille and effectively prevents obstruction of sound transmission from the speaker. [Means for solving the problem]

[0006] The present invention relates to a method for manufacturing a speaker grille, wherein the upper side of a perforated grille having a plurality of through holes is decorated with a surface material, A resin sheet is placed on top of the perforated grill, and the perforated grill and the resin sheet are heated to melt the resin sheet in a melting step. The process is followed by a pressing step in which the surface material is placed on top of the molten resin sheet, and the punching grill, the resin sheet, and the surface material are pressed together. The resin constituting the resin sheet is characterized by being polyamide.

[0007] According to the speaker grille manufacturing method of the present invention, the speaker grille can be easily manufactured by overlapping a resin sheet on top of a perforated grille and melting it, and then overlapping a surface material on top of the molten resin sheet and pressing it to adhere the surface material to the perforated grille. Furthermore, because the resin constituting the resin sheet is polyamide, in the melting process, the molten resin sheet conforms to the perforated grille due to the hydrogen bonding of the polyamide, is pulled by the perforated grille, and is perforated along the through-holes of the perforated grille without blocking them. As a result, the speaker grille can effectively prevent obstruction of sound transmission from the speaker.

[0008] In the above-described method for manufacturing a speaker grille, the surface material can be a synthetic resin fabric material.

[0009] According to this, since the speaker grille's outer layer is made of synthetic resin fabric, it can effectively prevent obstruction of sound transmission from the speaker. Furthermore, because the fibers of the synthetic resin fabric penetrate the molten resin sheet through an anchoring effect and adhere firmly, it can achieve excellent adhesion strength.

[0010] In addition, in the method for manufacturing the speaker grill, the synthetic resin fibers constituting the synthetic resin fabric member can be coated with a low melting point resin.

[0011] According to this, since the low melting point resin covering the synthetic resin fibers constituting the synthetic resin fabric member of the speaker grill melts and dissolves into the molten resin sheet and adheres firmly, the adhesion strength can be excellent.

[0012] In addition, in the method for manufacturing the speaker grill, the punching grill can have an aperture ratio of 40 to 60%.

[0013] According to this, the adhesion area of the resin sheet can be ensured, and effectively preventing the inhibition of the transmission of sound from the speaker can be achieved.

Effect of the Invention

[0014] According to the method for manufacturing the speaker grill of the present invention, it can be manufactured simply, and effectively preventing the inhibition of the transmission of sound from the speaker can be achieved.

Brief Description of the Drawings

[0015] [Figure 1] FIG. (A) is an image diagram of a state where the punching grill and the resin sheet disposed on the lower surface receiving jig in the melting step of the method for manufacturing the speaker grill of the present invention are heated from above and below, and FIG. (B) is an image diagram of a state where the lower surface receiving jig and the crimping press die in the crimping step crimp the punching grill, the resin sheet, and the skin member.

Mode for Carrying Out the Invention

[0016] Hereinafter, a method for manufacturing a speaker grill according to an embodiment of the present invention will be described. The scope of the present invention is not limited to the scope disclosed in the embodiment. The speaker grill 1 according to the embodiment covers a speaker disposed in an automobile interior and is used for the purpose of protecting the speaker.

[0017] As shown in Fig. 1(B), in the speaker grill 1 of the embodiment, the upper side (front side) of the punching grill 2 having a plurality of through holes (not shown) is decorated with a synthetic resin fabric member 4 as a skin member, and the synthetic resin fabric member 4 is pressure-bonded to the punching grill 2 by a resin sheet 3. Note that the orientation of the speaker grill 1 is such that the speaker side is the lower side (rear side) and the vehicle interior side is the upper side (front side).

[0018] The punching grill 2 is a metal plate having a plurality of through holes. Although the material of the metal plate is not particularly limited, it can be a general-purpose steel plate or a stainless steel plate (SUS (Steel Use Stainless)). As another embodiment, the steel plate can be an electrolytic zinc-plated steel plate (SECC (Steel Electrolytic Cold Commercial)) subjected to rust prevention treatment.

[0019] The plate thickness of the punching grill 2 can be 0.3 to 1.0 mm. This is because it is possible to ensure the bending workability in the pressure-bonding process while ensuring the strength as the speaker grill 1. If the plate thickness of the punching grill 2 is less than 0.3 mm, the strength as the speaker grill 1 may be inferior. On the other hand, if the plate thickness exceeds 1.0 mm, the bending workability in the pressure-bonding process may be inferior. As another embodiment, the plate thickness of the punching grill 2 can be 0.4 to 0.8 mm.

[0020] The opening ratio of the perforated grille 2 can be set to 40-60%. This is because it ensures the strength of the perforated grille 2 and the contact area of ​​the resin sheet 3, while effectively preventing obstruction of sound transmission from the speaker. If the opening ratio of the perforated grille 2 is less than 40%, there is a risk that sound transmission from the speaker will be obstructed. On the other hand, if the opening ratio exceeds 60%, there is a risk that the strength of the perforated grille 2 will be inferior, and the contact area of ​​the resin sheet 3 will not be ensured, which may cause deformation or peeling of the synthetic resin fabric member 4 when the surface of the speaker grille 1 is subjected to load or stress. In another embodiment, the opening ratio of the perforated grille 2 can be set to 40-50%.

[0021] The diameter of the through-holes in the perforated grille 2 can be 0.5 to 5.0 mm. This is because the resin sheet 3 does not block the through-holes, thereby suppressing deformation and peeling of the synthetic resin fabric member 4. If the diameter of the through-holes in the perforated grille 2 is less than 0.5 mm, the resin sheet 3 may block the through-holes. On the other hand, if the diameter of the through-holes exceeds 5.0 mm, deformation and peeling of the synthetic resin fabric member 4 may occur when the surface of the speaker grille 1 is subjected to load or stress. In another embodiment, the diameter of the through-holes in the perforated grille 2 can be 1.5 to 2.5 mm.

[0022] Furthermore, the perforated grille 2 can be coated with cationic electrodeposition paint on its surface. By applying cationic electrodeposition paint, the corrosion resistance of the perforated grille 2 can be improved. It is also presumed that the cationic coating applied to the perforated grille 2 improves its affinity with hydrogen bonds during the melting of the resin sheet 3, strengthening the tension of the molten resin to the perforated grille 2, and making it easier for the resin sheet 3 to be perforated along the through-holes of the perforated grille 2 without blocking them. Cationic electrodeposition painting can be performed using a general-purpose cationic electrodeposition painting machine and general-purpose cationic electrodeposition paint. Examples of general-purpose cationic electrodeposition paints that can be used include the Power Float series (manufactured by Nippon Paint Industrial Coatings Co., Ltd.), the Power Nix series (manufactured by Nippon Paint Industrial Coatings Co., Ltd.), and the Electron series (manufactured by Kansai Paint Co., Ltd.).

[0023] The resin sheet 3 is melted to weld the synthetic resin fabric member 4 to the perforated grille 2. The resin sheet 3 can be composed of polyamide or polyurethane. These are thermoplastic resins that can be hot-melted, and because the resin sheet 3 is made of polyamide or polyurethane, it is perforated along the perforations of the perforated grille 2 without blocking them during the melting process. Polyamide and polyurethane have hydrogen bonds, and it is presumed that these hydrogen bonds allow them to adhere to the metal perforated grille 2, and during the melting process to melt the resin sheet 3, the molten resin is pulled by the perforated grille 2, causing it to perforate along the perforations of the perforated grille 2 without blocking them.

[0024] The resin that makes up the resin sheet 3 can also be a commercially available hot melt resin. As polyamide hot melt resins, THERMETAL series (manufactured by Toagosei Co., Ltd.), TECHNOMELT series (manufactured by Henkel Japan Ltd.), and polyamide hot melt SHM series (manufactured by Seedam Co., Ltd.) can be used. As polyurethane hot melt resins, Elastran series (manufactured by BASF Japan Ltd.), U-Fine series (manufactured by AGC Inc.), and Tyforce series (manufactured by DIC Corporation) can be used. These block-shaped materials can, of course, be processed into sheets by adjusting the thickness before use.

[0025] In yet another embodiment, the resin material constituting the resin sheet 3 can be polyamide, due to its excellent water resistance. The resin composition refers to the main component (50% by mass or more). The resin constituting the resin sheet 3 may also be a mixture of resins, and the main component that best exhibits the characteristics of the resin is used as the resin composition.

[0026] The basis weight of resin sheet 3 is 20-200 g / m². 2 This is possible because the synthetic resin fabric member 4 can be welded to the perforated grill 2 with sufficient adhesion strength. The basis weight of the resin sheet 3 is 20 g / m². 2 If the weight is less than 200 g / m², the thickness of the molten resin will be thin, the anchoring effect of the fibers of the synthetic resin fabric member 4 will be weak, and the adhesion strength may be inferior. On the other hand, if the weight is 200 g / m², the thickness will be thin, the anchoring effect of the fibers of the synthetic resin fabric member 4 will be weak, and the adhesion strength may be poor. 2 If the amount exceeds this, there will be an excess of resin, and the amount of heat required to melt the resin will be high, which may be uneconomical. In another embodiment, the basis weight of the resin sheet 3 is 40 to 100 g / m². 2 It can be done this way.

[0027] The melting point (heat resistance temperature) of the resin sheet 3 can be set to 60-200°C. This is because the resin sheet 3 has excellent heat resistance and can be easily fused in the fusion process. If the melting point of the resin sheet 3 is less than 60°C, the resin sheet 3 may flow when the car to which the speaker grille 1 is attached is placed in direct sunlight, potentially causing deformation of the synthetic resin fabric member 4. On the other hand, if the melting point of the resin sheet 3 exceeds 200°C, the heating temperature in the fusion process will be 200°C or higher, requiring a large amount of heat to melt the resin, which may be uneconomical. In another embodiment, the melting point of the resin sheet 3 can be set to 80-180°C, and in yet another embodiment, it can be set to 100-160°C. The heating temperature in the fusion process of the resin sheet 3 will be 10-50°C higher than the melting point (heat resistance temperature).

[0028] The synthetic resin fabric member 4 is used to decorate the surface (upper side) of the speaker grille 1. As it is a fabric (fiber) member, it effectively prevents obstruction of sound transmission from the speaker, and the fibers penetrate the molten resin sheet 3 through an anchoring effect, resulting in a strong bond.

[0029] Polyamide, polyester, polypropylene, etc., can be used as the resin composition for the synthetic resin fabric member 4. These materials are flexible and have excellent weather resistance. In another embodiment, polyester with excellent weather resistance, particularly PET (Poly Ethylene Terephthalate), can be used. The resin constituting the synthetic resin fabric member 4 may contain coloring pigments for coloring, plasticizers to enhance flexibility, and ultraviolet absorbers to enhance weather resistance. Commercially available general-purpose products can be used for the coloring pigments, plasticizers, and ultraviolet absorbers.

[0030] Further, the synthetic resin fabric member 4 can be such that the fibers constituting the fabric member are coated with a low melting point resin. This is because the low melting point resin melts and penetrates into the molten resin sheet 3 and adheres firmly, so that the speaker grill 1 can have excellent adhesion strength. The low melting point resin is a resin having a lower melting point than the fibers constituting the fabric member, and polyethylene (low density polyethylene), (meth)acrylic resin, etc. can be used. Note that the synthetic resin fabric member 4 can also use fibers having a core-sheath structure with a low melting point resin as the sheath.

[0031] The basis weight of the synthetic resin fabric member 4 can be 50 to 500 g / m 2 This is because the synthetic resin fabric member 4 has strength against breakage and can effectively prevent the transmission of sound from the speaker from being inhibited. If the basis weight of the synthetic resin fabric member 4 is less than 50 g / m 2 , the synthetic resin fabric member 4 may be damaged by external factors such as scratching. On the other hand, if the basis weight exceeds 500 g / m 2 , the transmission of sound from the speaker may be inhibited. As another embodiment, the basis weight of the synthetic resin fabric member 4 can be 75 to 300 g / m 2 and, as yet another embodiment, the basis weight can be 100 to 200 g / m 2 .

[0032] Next, the manufacturing method of the speaker grill 1 of the embodiment will be described. The manufacturing method of the speaker grill 1 of the embodiment is composed of a melting step and a pressure bonding step.

[0033] The melting process, as shown in Figure 1(A), involves placing a punching grill 2, with a resin sheet 3 superimposed on top, onto a lower support jig 31 molded to the shape of the speaker grill 1, and then heating the punching grill 2 and the resin sheet 3 to melt the resin sheet 3. The punching grill 2 and the resin sheet 3 are heated by heat H from the lower support jig 31 and by heat H from far-infrared heaters (not shown) placed at intervals above the resin sheet 3.

[0034] Heating from the lower support fixture 31 is performed using a thermoelectric element so that the lower support fixture 31 reaches a temperature 10 to 50 degrees higher than the melting point of the resin sheet 3. Heating from the far-infrared heater heats the resin sheet 3 from above. Heating continues until the resin sheet 3 melts. When the resin sheet 3 melts, the molten resin sheet 3 conforms to the perforated grill 2 due to hydrogen bonds present in the resin, is pulled by the perforated grill 2, and is perforated along the through-holes of the perforated grill 2 without blocking them. After the resin sheet 3 melts, heating from the thermoelectric element and far-infrared heater is stopped.

[0035] The lower support jig 31 is a jig for heating the perforated grille 2 and the resin sheet 3, and its shape is matched to the product shape of the speaker grille 1. Because it is matched to the product shape of the speaker grille 1, the shape of the lower support jig 31 can be not only flat, but also curved surfaces such as concave and convex surfaces. In addition, the perforated grille 2 can be pre-matched to the product shape of the speaker grille 1.

[0036] The pressing process, as shown in Figure 1(B), involves placing a punching grill 2, which has a molten resin sheet 3 on its surface, on a lower support jig 31, that is, immediately after the melting process, on top of the molten resin sheet 3, and then pressing the punching grill 2, resin sheet 3, and synthetic resin fabric member 4 together. The pressing is performed using a pressing die 32 that matches the shape of the lower support jig 31 (the product shape of the speaker grill 1). Because the synthetic resin fabric member 4 is pressed onto the molten resin sheet 3, the fibers of the synthetic resin fabric member 4 penetrate into the molten resin sheet 3, and the synthetic resin fabric member 4 can adhere firmly to the resin sheet 3 by an anchoring effect. Furthermore, if the synthetic resin fabric member 4 is made of fibers that are coated with a low-melting-point resin, the low-melting-point resin melts into the molten resin sheet 3, allowing for an even stronger adhesion. [Examples]

[0037] The specifications for the perforated grille 2 used in the example are shown in Table 1, the specifications for the resin sheet 3 are shown in Table 2, and the specifications for the synthetic resin fabric member 4 are shown in Table 3.

[0038] [Table 1]

[0039] [Table 2]

[0040] [Table 3] In the examples, the resin sheets were evaluated by conducting puncture tests, peel strength tests, and creep tests after repeated heating and cooling cycles. The evaluation methods for each test are as follows.

[0041] <Perforation test of resin sheets> The perforation test of the resin sheet confirmed whether the molten resin sheet 3 perforated along the perforations of the perforating grill 2 without blocking them during the melting process. The results were evaluated as follows: ○ if the molten resin sheet 3 perforated along all of the perforations of the perforating grill 2, △ if it perforated 90% or more of the perforations, and × if it perforated less than 90% of the perforations.

[0042] <Peel Strength Test> For the peel strength test as an indicator of adhesion strength, an attachment was attached to the synthetic resin fabric member 4 side (surface side) of the speaker grille 1 with epoxy adhesive, and the maximum strength (peel strength) was determined by pulling the attachment. The peel strength was 0.5 N / mm². 2 The above items are marked with ○, 0.1 N / mm 2 More than 0.5N / mm 2 Values ​​less than 0.1 N / mm² are indicated by △. 2 Values ​​less than a certain value were marked with an "x".

[0043] <Creep test after repeated heating and cooling cycles> The creep test after repeated heating and cooling cycles involves conducting repeated heating and cooling cycles simulating freeze-thaw cycles, followed by a creep test to assess the peelability of the fabric component. For the repeated heating and cooling cycles, speaker grille 1 was subjected to four cycles: 18 hours in a 50°C, 95% humidity environment, 3 hours in a -30°C environment, and 3 hours in an 80°C environment. For the creep test, an attachment (φ10mm) was attached to the synthetic resin fabric component 4 side (surface side) of speaker grille 1 with epoxy adhesive. The synthetic resin fabric component 4 side was then placed downwards, a 100g weight was suspended from the attachment, and the grille was left in an 80°C environment for 24 hours to observe its condition. The condition was evaluated as follows: ○ if no peeling of the synthetic resin fabric component 4 was observed, △ if peeling was observed but did not extend beyond the attachment surface, and × if peeling beyond the attachment surface was observed.

[0044] Table 4 lists the test examples and the evaluation results of the above tests for each test example. Test examples 1-4 and 6-9 are examples, and test example 5 is a comparative example.

[0045] [Table 4] (Test Example 1) The melting process in Test Example 1 involves PG1, which is an electro-galvanized steel sheet (SPCC) with cationic electrodeposition coating applied to perforated acrylic 2, and then a resin sheet 3 containing 60 g / m² of polyamide. 2 The RS1 sheets were stacked and placed on the lower support jig 31, and heated at 150°C for 5 minutes using a thermoelectric element and a far-infrared heater. In this state, a perforation test of the resin sheet was performed, and it was found that the molten resin sheet 3 had perforated along all the through holes of the punching grill 2. In the crimping process, after stopping the heating of the thermoelectric element and far-infrared heater, a PET fabric (150g / m²) coated with low-density polyethylene was placed on top of the molten resin sheet 3 as a synthetic resin fabric member 4. 2 The RF1s were stacked and placed on the lower support jig 31, and then pressed together with a crimping press die 32 for 2 minutes. The speaker grille 1 of Test Example 1 obtained in this way showed a peel strength of 0.5 N / mm² in the peel strength test. 2 In conclusion, no delamination of the synthetic resin fabric member 4 was observed in the creep test after repeated heating and cooling cycles.

[0046] (Test Example 2) Test Example 2 involves using resin sheet 3 from Test Example 1 with polyamide 30 g / m². 2 This test was modified to use RS2, with all other conditions being the same as in Test Example 1. The test results showed that while peeling was observed in the creep test after repeated heating and cooling cycles, no peeling beyond the attachment surface was observed. This is presumed to be due to the low basis weight of the resin sheet 3. Other test results were the same as in Test Example 1.

[0047] (Test Example 3) Test Example 3 involves using a resin sheet 3 from Test Example 1 with polyamide at 150 g / m². 2This test was modified to use RS3, with all other conditions being the same as in Test Example 1. The test results were the same as in Test Example 1.

[0048] (Test example 4) Test Example 4 involves using resin sheet 3 from Test Example 1 with polyurethane at 60 g / m². 2 The RS4 was used, and the heating temperature in the melting process was set to 155°C, while other conditions were the same as in Test Example 1. The test results showed that while peeling was observed in the creep test after repeated heating and cooling cycles, no peeling beyond the attachment surface was observed. This is presumed to be due to hydrolysis of the polyurethane in resin sheet 3. Other test results were the same as in Test Example 1.

[0049] (Test Example 5) Test Example 5 involves using resin sheet 3 from Test Example 1 with polyethylene 60g / m². 2 The RS5 was used, and the heating temperature in the melting process was set to 160°C, while other conditions were the same as in Test Example 1. The test results showed that the perforation test of the resin sheet was rated as ×, meaning that not all through-holes were perforated. Since polyethylene does not have hydrogen bonds, it does not adhere well to the perforating grille 2, and it is presumed that the molten resin was not pulled by the perforating grille 2 during the melting process, causing the resin sheet 3 to block the through-holes of the perforating grille 2.

[0050] (Test Example 6) Test Example 6 is the same as in Test Example 1, except that the perforated grille 2 is made of electro-galvanized steel sheet (SPCC) PG2 without cationic electrodeposition coating, and all other conditions are the same. The test results were the same as in Test Example 1. In this test, the effect of cationic electrodeposition coating on the perforated grille 2 could not be confirmed.

[0051] (Test Example 7) Test Example 7 is the same as in Test Example 1, but with the perforated grille 2 replaced with PG3 made of cation-electrodeposited stainless steel plate (SUS304), while all other conditions were the same. The test results were the same as in Test Example 1. It was confirmed that cation-electrodeposited stainless steel plate can be used for the perforated grille 2.

[0052] (Test Example 8) Test Example 8 is the same as in Test Example 7, but with the perforated grille 2 replaced with PG4 made of stainless steel plate (SUS304) that has not been cationically electrodeposited. All other conditions were the same as in Test Example 7. The test results were the same as in Test Example 7. In this test, the effect of cationically electrodeposited coating on the perforated grille 2 could not be confirmed.

[0053] (Test Example 9) Test Example 9 involves replacing the synthetic resin fabric member 4 from Test Example 1 with polypropylene fabric (70g / m²). 2 The RF2 component was changed to the same as in Test Example 1, and all other conditions were the same. The test results were the same as in Test Example 1. However, because the synthetic resin fabric component 4 was not coated with a low-melting-point resin, the peel strength test was numerically inferior compared to Test Example 1. [Explanation of symbols]

[0054] 1. Speaker Grille 2 Perforated Grill 3. Resin sheet 4. Synthetic resin fabric component 31 Lower support jig 32 Crimping press molds H fever

Claims

1. A method for manufacturing a speaker grille in which the upper part of a perforated grille having multiple through holes is decorated with a surface material, A resin sheet is placed on top of the perforated grill, and the perforated grill and the resin sheet are heated to melt the resin sheet in a melting step. The process is followed by a pressing step in which the surface material is placed on top of the molten resin sheet, and the punching grill, the resin sheet, and the surface material are pressed together. A method for manufacturing a speaker grille, characterized in that the resin constituting the resin sheet is polyamide.

2. The method for manufacturing a speaker grille according to claim 1, characterized in that the surface material is a synthetic resin fabric material.

3. The method for manufacturing a speaker grille according to claim 2, characterized in that the synthetic resin fibers constituting the synthetic resin fabric member are coated with a low-melting-point resin.

4. The method for manufacturing a speaker grille according to claim 1, characterized in that the punching grille has an opening ratio of 40 to 60%.

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