A method for manufacturing an integrated molded motor sound insulation pad and the sound insulation pad

Abstract

The application embodiment provides a manufacturing method and a sound insulation pad of an integrated motor, and comprises the following steps: softening a cut EVA composite sheet; placing the softened EVA composite sheet into a vacuum forming mold to form a sound insulation pad blank by vacuum forming; cooling for a set time to shape the sound insulation pad blank after the vacuum forming; taking out the shaped sound insulation pad blank, wherein the taken-out sound insulation pad blank is composed of three parts connected in sequence, and has a folding area between the two adjacent parts; placing the sound insulation pad blank into a foaming mold, and setting a PP resin reinforcing gasket at a position where a mounting hole needs to be formed on the sound insulation pad blank; foaming in the foaming mold to form a sound insulation pad semi-finished product, and the sound insulation pad semi-finished product can be folded along the folding area on the sound insulation pad blank. The sound insulation pad produced by the application is integrally formed, uses less molds, and reduces the maintenance cost of the molds in the later period.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the technical field of motor sound insulation pad, and particularly relates to a manufacturing method of an integrally formed motor sound insulation pad and the sound insulation pad. BACKGROUND

[0002] With the development and popularization of new energy vehicles, the noise problem of the whole vehicle generated by the driving motor system is also concerned, mainly the obvious high-frequency noise generated by the vehicle during acceleration and deceleration, which seriously affects the comfort of the vehicle and the subjective feeling of the driver and the passenger. In order to meet the better driving experience, it is necessary to develop a sound insulation pad with simple manufacturing process and good high-frequency noise absorption effect.

[0003] At present, the design of the motor sound insulation pad is in the exploratory stage, and the existing electric vehicle sound insulation pad mostly uses non-woven fabric + polyurethane + non-woven fabric, hard felt + polyurethane or polyurethane + non-woven fabric + glass fiber + non-woven fabric, and is fixed by male and female buckles or expansion buckles. Since the motor body is in a cylindrical shape, the sound insulation pad wrapped on the motor is usually divided into several parts, such as upper and lower sound insulation pads or front and rear sound insulation pads. The sound insulation pad materials of these parts are the same, only the shapes are different. When producing, 2 molds are needed for the same process, that is, the number of molds is twice the number of sound insulation pads, the mold cost is high, and the mold maintenance cost is high. SUMMARY

[0004] The embodiment of the present application provides a manufacturing method of an integrally formed motor sound insulation pad and the sound insulation pad, relates to the technical field of motor sound insulation pad, and reduces the number of molds and the cost of later mold maintenance by designing an integrally formed sound insulation pad.

[0005] In a first aspect, the embodiment of the present application provides a manufacturing method of an integrally formed motor sound insulation pad, including the following steps:

[0006] The cut EVA composite sheet is softened;

[0007] The softened EVA composite sheet is placed in a vacuum forming mold to form a sound insulation pad blank by vacuum forming;

[0008] After vacuum forming, the sound insulation pad blank is cooled for a set time to shape the sound insulation pad blank;

[0009] The shaped sound insulation pad blank is taken out, and the taken-out sound insulation pad blank is composed of three parts connected in sequence, and has a folding area between adjacent two parts;

[0010] The sound insulation pad blank is placed in a foaming mold, and a PP resin reinforcing gasket is arranged at a position where a mounting hole needs to be arranged on the sound insulation pad blank;

[0011] foaming in a foaming mold to form a soundproofing mat semi-product, which can be folded along a folding area on the soundproofing mat blank;

[0012] putting the soundproofing mat semi-product on a water cutting mold to perform water cutting boundary and installation hole to obtain a soundproofing mat product.

[0013] Optionally, the blister mold has two partition strips, which divide the blister mold into a first blister area, a second blister area and a third blister area; the three parts of the soundproofing mat blank are formed by blistering in the first blister area, the second blister area and the third blister area respectively, and the EVA composite sheet at the corresponding position of the partition strip forms a folding area.

[0014] Optionally, the lower mold of the foaming mold is provided with a first foaming area, a second foaming area and a third foaming area corresponding to the first blister area, the second blister area and the third blister area; the three parts of the soundproofing mat blank taken out of the blister mold are respectively put into the corresponding first foaming area, second foaming area and third foaming area; foaming material is injected into the first foaming area, the second foaming area and the third foaming area; the upper mold of the foaming mold is combined with the lower mold of the foaming mold to perform foaming;

[0015] Optionally, the EVA composite sheet is made by the following method:

[0016] Put the powdered EVA raw material into a container, add additives and stir uniformly in the container, and heat the container until the EVA raw material becomes gelatinous;

[0017] Extrude the gelatinous EVA raw material to a roller to form the required thickness of the EVA sheet, and after cooling for a period of time, send the EVA sheet to a gluing equipment for gluing;

[0018] Cover a layer of non-woven fabric on the EVA sheet after gluing to form an EVA composite sheet, and then cut the EVA composite sheet according to needs.

[0019] Optionally, the cut EVA composite sheet is put into an oven for baking to soften the composite sheet, and the baking temperature is 295-310°C;

[0020] Optionally, the softened EVA composite sheet is sent to the blister mold by a conveyor belt, and after being laid, it is formed into the soundproofing mat blank by blistering.

[0021] Optionally, the blistering uses negative pressure adsorption, and the pressure is 0.4-0.6Mpa.

[0022] Optionally, the thickness of the soundproofing mat product is not less than 20mm, and the temperature of the foaming mold during foaming is kept at 55-65°C.

[0023] In a second aspect, the embodiments of the present application provide an integrally formed motor sound insulation pad, which is made by the manufacturing method described above.

[0024] Optionally, the mounting hole is located at a position corresponding to a position on the motor where a pipeline is mounted, and the pipeline is mounted on the motor through the mounting hole.

[0025] The present application can reduce the number of molds in the production process and reduce the maintenance cost of the molds in the later stage by designing the sound insulation pad to be integrally formed. The process of producing the sound insulation pad is simple, only two steps, vacuum forming + foaming forming process. The vacuum forming efficiency is high, no need to combine the upper and lower molds, no need for a press, less space occupation, simpler operation, higher safety, and the mounting hole of the sound insulation pad is reinforced by a PP resin reinforcing sheet to ensure the size and shape of the mounting hole during installation. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present specification, and other drawings can be obtained by those skilled in the art without creative labor.

[0027] Figure 1 A flow chart of a manufacturing method of an integrally formed motor sound insulation pad according to the present application;

[0028] Figure 2 A structure diagram of an EVA composite sheet according to the present application;

[0029] Figure 3 A structure diagram of a finished sound insulation pad according to the present application;

[0030] Figure 4 A mounting structure diagram of a bolt, a bolt fixing seat, a PP resin reinforcing gasket, an EVA layer, and a non-woven fabric layer.

[0031] Explanation of reference signs:

[0032] 1-non-woven fabric layer, 2-EVA layer, 3-PU foaming layer, 4-PP resin reinforcing gasket, 5-bolt fixing seat, 6-finished sound insulation pad, 7-bolt, 8-folding area.

DETAILED DESCRIPTION

[0033] In order to better understand the technical solutions of the present specification, the embodiments of the present application will be described in detail below with reference to the drawings.

[0034] It should be noted that the described embodiments are merely some of the embodiments of the present specification, rather than all the embodiments. Based on the embodiments in the present specification, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present specification.

[0035] The terms used in the embodiments of the present application are merely for the purpose of describing the specific embodiments, and are not intended to limit the present specification. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0036] The technical solutions protected by the embodiments of the present application will be described in detail below with reference to the drawings.

[0037] Please refer to Figure 1 A one-piece forming motor sound insulation pad manufacturing method provided by the embodiments of the present application comprises the following steps:

[0038] The cut EVA composite sheet is softened; wherein the EVA composite sheet is made by the following method:

[0039] The powdered EVA raw material is put into a container, and an additive is added into the container and stirred uniformly, and the container is heated until the EVA raw material becomes gelatinous;

[0040] The gelatinous EVA raw material is extruded onto a roller to form the required thickness of the EVA sheet, and after cooling for a period of time, the EVA sheet is sent to a gluing equipment for gluing; the gram weight of the EVA is controlled by the thickness of the roller, for example, the gram weight is ≥3600g / m2, and the thickness is ≥2mm;

[0041] A layer of non-woven fabric is covered on the glued EVA sheet to form an EVA composite sheet, and then the EVA composite sheet is cut according to the needs. The non-woven fabric serves to ensure good appearance and strengthen the EVA to prevent local thinning of the EVA during vacuum forming;

[0042] The softened EVA composite sheet is put into a vacuum forming mold to form a sound insulation pad blank; during softening, the cut EVA composite sheet can be put into an oven for baking to soften the composite sheet, and the baking temperature is 295-310℃, and 300℃ is the best. Softening the EVA composite sheet can facilitate subsequent vacuum forming;

[0043] After vacuum forming, the sound insulation pad blank is cooled for a set time to set the shape; for example, the cooling time can be 40s, 45s, 48s, 50s, etc.

[0044] The shaped sound insulation pad blank is removed. The removed sound insulation pad blank consists of three connected parts, with a folded area 8 between adjacent parts. (See reference) Figure 3 As shown; with this setting, the obtained sound insulation pad blank can be a continuous sheet shape, and the sound insulation pad blank can be folded along the folding area 8 to lay the foundation for the subsequent sound insulation pad finished product 6, so that the sound insulation pad finished product 6 can be folded along the folding area 8 to wrap the motor. Figure 3 The dotted line in the middle is the fold line along the folding area 8 when the sound insulation pad 6 is wrapped around the motor.

[0045] The sound insulation pad blank is placed in a foaming mold, and a PP resin reinforcing gasket 4 is placed at the position where an installation hole needs to be made on the sound insulation pad blank. In a specific implementation, the PP resin reinforcing gasket 4 can be glued to the position where an installation hole needs to be made, and the installation hole passes through the PP resin reinforcing gasket 4. Of course, as one embodiment, the PP resin reinforcing gasket 4 itself has a hole. When the PP resin reinforcing gasket 4 is glued to the sound insulation pad blank, the hole on the PP resin reinforcing gasket 4 is aligned with the position of the installation hole to be made on the sound insulation pad blank, and the installation hole passes through the hole on the PP resin reinforcing gasket 4.

[0046] By setting PP resin reinforcing gaskets 4, the strength of the mounting hole can be increased, preventing the mounting hole from cracking during use. At the same time, it can prevent the edge of the mounting hole from being worn by the bolt during bolt installation.

[0047] The sound insulation pad semi-finished product is formed by foaming in a foaming mold, and the sound insulation pad semi-finished product can be folded along the folding area 8 on the sound insulation pad blank;

[0048] The semi-finished sound insulation pad is placed on a water-cutting membrane to cut the boundary and installation holes, so as to obtain the finished sound insulation pad 6.

[0049] To achieve one-time molding of the motor sound insulation pad, the following measures are adopted: the vacuum forming mold has two dividing strips, which divide the vacuum forming mold into a first vacuum forming area, a second vacuum forming area, and a third vacuum forming area; the three parts of the sound insulation pad blank are respectively vacuum formed by the first vacuum forming area, the second vacuum forming area, and the third vacuum forming area, and the EVA composite sheet at the corresponding position of the dividing strip forms a folded area 8.

[0050] The lower mold of the foaming mold is provided with a first foaming area, a second foaming area and a third foaming area corresponding to the first suction area, the second suction area and the third suction area; the three parts of the sound insulation pad blank taken out from the suction mold are respectively placed in the first foaming area, the second foaming area and the third foaming area; the foaming material is injected into the first foaming area, the second foaming area and the third foaming area; and the upper mold of the foaming mold is combined with the lower mold of the foaming mold to perform foaming. In the specific implementation, the foaming material uses PU foaming, the A material for PU foaming is foaming agent + catalyst + polyether polyol, the foaming agent is ammonia, and the catalyst is silicon oil; the B material is isocyanate; after the A material and the B material are mixed in a ratio of 100:60, the mixed A material and B material are simultaneously extruded into the foaming mold through a spray gun; when the temperature of the foaming mold is kept at 55-65℃, the best temperature is 60℃, so that the A material and the B material can be foamed at a certain speed and abnormal pores are not generated; and the foaming time is about 180s.

[0051] As an implementation manner, the softened EVA composite sheet is sent to the suction mold through a conveying belt, and after being well laid, suction forming is performed to form the sound insulation pad blank. In this way, the temperature of the softened EVA composite sheet is prevented from being too high to scald the workers, and the efficiency is improved. After the suction forming is completed, the sound insulation pad blank after shaping is taken out and also conveyed to the foaming mold through the conveying belt.

[0052] The suction forming adopts negative pressure adsorption, and the pressure is 0.4-0.6Mpa, preferably 0.5Mpa.

[0053] The thickness of the sound insulation pad product 6 is not less than 20mm, so as to meet the requirements of NVH.

[0054] The material layers of the sound insulation pad prepared by the above method are, from the outside to the inside of the motor surface, a non-woven fabric layer 1, an EVA layer 2, a PU foaming layer 3, as shown in Figure 2 , the positions of the local mounting fixed points are a non-woven fabric layer 1, an EVA layer 2, a PP resin reinforcing gasket 4 and a PU foaming layer 3, as shown in Figure 4 ;

[0055] The embodiment of the present application also provides an integrally formed motor sound insulation pad, which is prepared by the manufacturing method.

[0056] The positions where the mounting holes are located correspond to the positions where pipes are mounted on the motor, and the pipes are mounted on the motor through the mounting holes. In order to further fix, a bolt fixing seat 5 can be welded on the motor, and mounting holes matched with the bolts are formed on the sound insulation pad. For details, refer to Figure 4As shown, when the mounting hole matched with the bolt is opened on the sound insulation pad, the mounting hole can be opened in the direction from the PU foaming layer 3 to the non-woven fabric layer 1 into a stepped hole including a first hole and a second hole, the hole diameter of the first hole is larger than the hole diameter of the second hole, the hole diameter of the first hole is larger than the diameter of the bolt fixing seat 5, the first hole is opened to penetrate the PU foaming layer 3 but not to penetrate the PP resin reinforcing pad 4, so that the bolt fixing seat 5 abuts against the PP resin reinforcing pad 4 during installation; the second hole is opened to penetrate the non-woven fabric layer 1, the EVA layer 2 and the PP resin reinforcing pad 4. When the sound insulation pad is installed, the stud of the bolt 7 penetrates the second hole and matches with the bolt fixing seat 5, and the head of the bolt 7 abuts against the non-woven fabric layer 1.

[0057] When the sound insulation pad is installed on the motor, the bolt 7 is used for fixing, although the non-woven fabric and the PP resin reinforcing pad 4 are provided at the mounting hole, in order to avoid excessive torque and damage the EVA, the torque of the bolt is limited to 4-6 N. The installation point of the motor sound insulation pad and the installation point of the pipeline are shared, that is, no additional male and female buckles or expansion buckles are needed to fix, thereby saving the cost.

[0058] The sound insulation pad is designed to be integrally formed, so that the number of molds in the production process can be reduced, and the maintenance cost of the mold in the later stage can be reduced; the process for producing the sound insulation pad is simple, only two steps of suction molding and foaming molding are needed; the suction molding efficiency is high, no upper and lower mold closing is needed, no press is needed, the occupied space is small, the operation is simpler, and the safety is higher; the PP resin reinforcing sheet is used at the mounting hole of the sound insulation, so that the size and shape of the mounting hole during installation are ensured, the sound insulation pad is formed by the suction molding mode, integrally formed, the process is simple and efficient, the sound insulation pad uses the EVA+non-woven fabric material, the sound absorption effect is better, and the molding is simple.

[0059] The above only describes the preferred embodiments of the present application, and does not limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of manufacturing an integrated molded motor sound insulation pad, characterized by, The method comprises the following steps: cutting the EVA composite sheet; softening the EVA composite sheet; putting the softened EVA composite sheet into a vacuum forming mold to form a sound insulation pad blank; cooling the sound insulation pad blank for a certain time to shape the sound insulation pad blank; taking out the shaped sound insulation pad blank, which is composed of three parts connected in sequence, and has a folding area between two adjacent parts; putting the sound insulation pad blank into a foaming mold, and setting a PP resin reinforcing gasket at a position where a mounting hole is needed on the sound insulation pad blank; foaming in the foaming mold to form a sound insulation pad semi-finished product, which can be folded along the folding area on the sound insulation pad blank; putting the sound insulation pad semi-finished product onto a water cutting membrane to perform water cutting on the boundary and mounting hole, so as to obtain a sound insulation pad finished product; the vacuum forming mold has two division strips, which divide the vacuum forming mold into a first vacuum forming area, a second vacuum forming area and a third vacuum forming area; the three parts of the sound insulation pad blank are formed by vacuum forming in the first vacuum forming area, the second vacuum forming area and the third vacuum forming area respectively, and the EVA composite sheet at the corresponding position of the division strips forms a folding area; 2. The method of claim 1, wherein the lower mold of the foaming mold is provided with a first foaming area, a second foaming area and a third foaming area corresponding to the first vacuum forming area, the second vacuum forming area and the third vacuum forming area; the three parts of the sound insulation pad blank taken out from the vacuum forming mold are put into the corresponding first foaming area, second foaming area and third foaming area; foaming material is injected into the first foaming area, the second foaming area and the third foaming area; and the upper mold of the foaming mold is combined with the lower mold of the foaming mold to perform foaming. The EVA composite sheet is made by the following method: putting the powdered EVA raw material into a container, adding additives in the container and stirring uniformly, and heating the container until the EVA raw material becomes gelatinous; extruding the gelatinous EVA raw material to a roller to form an EVA sheet with a desired thickness, and sending the EVA sheet to a gluing equipment after cooling for a period of time; 3. The method of claim 1, wherein covering a layer of non-woven fabric on the EVA composite sheet, and then cutting the EVA composite sheet according to needs.

4. The method of claim 1, wherein putting the cut EVA composite sheet into an oven to soften the composite sheet, and the oven temperature is 295-310°C.

5. The method of claim 1, wherein sending the softened EVA composite sheet to the vacuum forming mold by a conveyor belt, and performing vacuum forming after laying the EVA composite sheet to form the sound insulation pad blank.

6. The method of claim 1, wherein The vacuum forming adopts negative pressure adsorption, and the pressure is 0.4-0.6Mpa.

7. An integrally formed motor sound insulation pad, characterized by The thickness of the sound insulation pad finished product (6) is not less than 20mm, and the temperature of the foaming mold is kept at 55-65°C during foaming.

8. The integrally formed motor sound insulation pad of claim 7, wherein, The sound insulation pad is made by the manufacturing method of any one of claims 1-6. The position where the mounting hole is located corresponds to the position of the pipeline mounted on the motor, and the pipeline passes through the mounting hole and is mounted on the motor.

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