KR102167401B1 - Carbon fiber or CNT composite materials and suspension bearing for smallsize vehicle without insert therewith - Google Patents

Abstract

The present invention relates to a carbon fiber or a CNT composite material and a suspension bearing for a small-size car without an insert using the same, which can reduce the weight of a product while providing excellent performance by providing desired performance without installing an insert inside a body housing of a body, is friendly, can significantly improve impact resistance, tensile strength and impact strength, and can reduce specific gravity by injection-molding the housing with PA66 and a mixture of a carbon fiber composite material or a CNT composite material, shorten a process time, maximize production volume, and reduce work costs significantly by manufacturing the body, a sealing body, and a damper through a series of processes through third injection molding, and can completely block the inflow of foreign matter and moisture from the outside by installing the sealing body between the body and the damper through secondary injection molding.

Description

Carbon fiber or CNT composite materials and suspension bearing for small size vehicle without insert therewith

The present invention relates to a carbon fiber composite material or a CNT composite material, and a suspension bearing for a compact vehicle in which the insert using the same is removed, and in detail, the insert is removed from the inside of the body to reduce the overall load of the product and at the same time primary injection molding Carbon fiber composite material or CNT composite material that is eco-friendly and can improve performance such as impact resistance, tensile strength, and impact strength by including carbon fiber composite material or CNT composite material in the material of the body, and for small cars with the insert removed It relates to a suspension bearing.

Suspension is a vehicle suspension device that connects the axle and the vehicle body to support the weight of the vehicle and at the same time alleviates the vertical vibration of the wheel so that the vibration or impact energy transmitted from the tire is not transmitted directly to the vehicle body. It is a device to prevent the load, and it is classified into mechanical spring type and fluid spring according to the tuning of the spring.

In particular, the strut suspension has a simple structure and a built-in shock absorber, and the high point where the shock absorber is mounted allows accurate alignment setting, less change in alignment values, and a wide range of road impacts. Due to its decentralized advantage, it is currently mainly installed in passenger cars.

1 is a side cross-sectional view showing a suspension thrust bearing device disclosed in Korean Patent Registration No. 10-1345852 (name of the invention: suspension thrust bearing device and strut).

The suspension thrust bearing device (hereinafter referred to as the prior art) 101 of FIG. 1 includes a rolling bearing 117 forming an axial thrust bearing, and a rolling bearing 117 provided with a body 122 made of a synthetic material. The lower support cap 116, the upper support cap 115 of the rolling bearing 117, the vibration-filtering element 125 mounted on the body 122 of the lower support cap 116, and the shaft relative to each other A bearing seat 102 provided with an upper cup 107 and a lower cup 108 supporting in the direction and a rubber block 109 clamped in the axial direction between the cups, and a shaft provided with a bearing surface for a damping buffer It consists of a cup 128 having a directional portion 128a and a radial portion 128b.

At this time, the constituent means including the upper support cap 115, the lower support cap 116, the rolling bearing 117, and the filtering element 125 are referred to as suspension bearings.

In addition, the body 122 is made of a composite material in which PA66 material and glass fiber are mixed.

In the prior art 101 configured as described above, the gap between the lower support cap 116 and the cup 128 is blocked by the filtering element 125 so that the inflow of foreign matter and moisture into the rolling bearing 117 can be blocked. do.

However, since the main body 122 of the prior art 101 is made of a composite material in which a PA66 material and glass fiber are mixed, there is a problem in that environment-friendly properties are very poor.

In addition, since the main body 122 of the prior art 101 continuously generates external shocks and vibrations according to the characteristics of the installation environment installed between the knuckle of the wheel and the vehicle body, the impact resistance, tensile strength and impact strength above the threshold must be secured. , In the past, since the material of the main body 122 is made of a composite material of a mixture of PA66 material and glass fiber, performance improvement is insufficient, and the phenomenon that the main body 122 is damaged due to external shock, friction, and vibration occurs uncommonly. have.

In addition, the prior art 100 has a problem that impact resistance, impact strength, and tensile strength are significantly deteriorated because the insert is not inserted into the body 122, and recently, in order to solve this problem, the inside of the body 122 Although inserts are placed, this device has the disadvantage of increasing the load on the product due to the insert.

The present invention is to solve such a problem, and the problem of the present invention is that it is possible to exhibit the desired performance without installing an insert inside the body housing of the body, so that the carbon has excellent performance and can reduce the load of the product. It is to provide a fiber composite material or a CNT composite material, and a suspension bearing for a compact vehicle in which the insert using the same is removed.

In addition, another problem of the present invention is that by mixing PA66 with a material of carbon fiber composite material or CNT composite material to fabricate a body, it is eco-friendly and can significantly increase performance such as impact resistance, tensile strength and impact strength, and It is to provide a carbon fiber composite material or a CNT composite material that can be reduced, and a suspension bearing for a small vehicle from which the insert using the same is removed.

In addition, another problem of the present invention is that the body, sealing body and dumper are manufactured in a series of processes through the third injection molding, thereby shortening the process time and maximizing the production volume, and at the same time, a carbon fiber composite material that can significantly reduce work costs. Or, it is to provide a CNT composite material and a suspension bearing for a compact vehicle in which the insert using the same is removed.

In addition, another problem of the present invention is a carbon fiber composite material or CNT that can thoroughly block the inflow of foreign substances and moisture from the outside by the sealing body by installing a sealing body between the body and the dumper through secondary injection molding. It is to provide a composite material and a suspension bearing for a compact vehicle in which the insert using the same is removed.

In the suspension bearing of the present invention for solving the above problem, comprising a body and bearing balls (B), and installed in a vehicle suspension: The body is formed in a cylindrical shape with an upper and lower portion open, A body housing through which the piston rod of the shock absorber passes through the upper and lower openings; An extension part formed to extend vertically outward to the upper end of the body housing and connected along an arc; It includes a protruding plate formed in a hollow cylindrical shape having an inner diameter larger than that of the body housing and connected to the upper surface of the expansion part, and at a point where the upper surface of the expansion part formed on the inner side of the protrusion plate and the inner circumferential surface of the protrusion plate are connected The seating grooves in which the bearing balls (B) are seated are repeatedly formed along an arc, and the body is made of a synthetic material, and the manufacturing method (S1) of the synthetic material is a dispersion by mixing a water-dispersible acrylic-based anion resin with distilled water. Preparation of the dispersion to prepare; A coating step of injecting CNT (carbon nanotube) or carbon fiber into a stirrer, and then spraying the dispersion obtained by the dispersion preparation step to coat CNT or carbon fiber with a water-dispersible acrylic anionic resin; A moisture evaporation step of evaporating the moisture of the mixture by the coating step; A compression and pelletizing step of extruding the mixture obtained by the water evaporation step with an extruder to produce CNT pellets or carbon fiber pellets; A polymer material mixing step of mixing and compounding CNT pellets or carbon fiber pellets by the compression and pelletizing step and a polymer material to prepare a CNT composite material or a carbon fiber composite material; Including a PA66 mixing step of preparing the mixed material by mixing and stirring the CNT composite material or carbon fiber composite material by the polymer material mixing step with PA66, the polymer material mixing step is CNT pellets or carbon fiber pellets 10 ~ 25 A CNT composite material or a carbon fiber composite material is prepared by mixing wt%, 40 to 70 wt% of a polypropylene resin, and 5 to 35 wt% of styrene-ethylene-butylene-styrene (SEBS).

In addition, in the present invention, the suspension bearing further includes a first sealing body, a second sealing body, and a dumper, and a first sealing body insertion groove is formed to be connected along an arc on an upper surface adjacent to the outer edge of the expansion part, and the A second sealing body insertion groove is formed in an inner edge of the upper surface of the expansion part formed on the inside of the protrusion plate to be connected along an arc, and the first sealing body is coupled to the first sealing body insertion groove of the expansion part, It is preferable that the second sealing body is coupled to the second sealing body insertion groove of the expansion part, and the dumper is installed to surround the outer side from the lower surface of the expansion part to the lower end of the body housing.

In addition, in the present invention, the body is manufactured through primary injection molding by a primary mold device, and the first sealing body and the second sealing body are placed in a secondary mold device in which the primary injection molding is placed inside the cavity. It is manufactured through secondary injection molding by, and the dumper is preferably manufactured through a third injection molding by a tertiary mold apparatus in which the secondary injection molded object is disposed inside the cavity.

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In addition, in the present invention, the PA66 mixing step is preferably mixed and stirred with 15 to 40% by weight of the composite material and 60 to 85% by weight of the PA66.

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In addition, in the present invention, the coating step is sprayed on CNTs so that 98.5 to 99.40% by weight of CNT or the carbon fiber and 0.60 to 1.44% by weight of a water-dispersible acrylic anionic resin are mixed, and the step of preparing the dispersion is a water-dispersible acrylic anionic resin. (11) It is preferable to prepare a dispersion by mixing 5.0 to 10.0% by weight and 90.0 to 95.0% by weight of distilled water (13).

According to the present invention having the above problems and solutions, since the desired performance can be exhibited without installing an insert in the body housing of the body, it is possible to reduce the load of the product while having excellent performance.

In addition, according to the present invention, the housing is injection-molded from a material that is a mixture of PA66 and carbon fiber composite material or CNT composite material, so that it is friendly and can significantly improve impact resistance, tensile strength and impact strength, and reduce specific gravity. You can make it.

In addition, according to the present invention, the body, the sealing body, and the dumper are manufactured through a series of processes through the third injection molding, so that the process time can be shortened to maximize the production amount and at the same time significantly reduce the operation cost.

In addition, according to the present invention, by installing the sealing body between the body and the dumper through the secondary injection molding, it is possible to thoroughly block the inflow of foreign substances and moisture from the outside by the sealing body.

1 is a side cross-sectional view showing a suspension thrust bearing device disclosed in Korean Patent Registration No. 10-1345852 (name of the invention: suspension thrust bearing device and strut).
2 is a flowchart illustrating a method of manufacturing a suspension bearing for a compact vehicle according to an embodiment of the present invention.
3 is a perspective view showing a body manufactured in the first injection molding step of FIG. 2.
4 is a side view of FIG. 3.
5 is a perspective view showing an injection-molded product in the second injection molding step of FIG. 2.
6 is a perspective view showing a third injection product manufactured by the third injection molding step of FIG. 2.
7 is a perspective view showing a suspension bearing for a compact vehicle according to an embodiment of the present invention.
FIG. 8 is a process flow chart showing a method of manufacturing a composite material injected in the first injection molding step of FIG. 2 and used as a material for a body.
9 is a block diagram illustrating a dispersion prepared by the dispersion manufacturing step of FIG. 8.
10 is a block diagram showing a CNT composite material or a carbon fiber composite material manufactured by the polymer material mixing step (S70) of FIG.

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

2 is a flowchart for explaining a method of manufacturing a suspension bearing for a compact vehicle with an insert removed, which is an embodiment of the present invention.

An embodiment of the present invention, the suspension bearing 1 for a compact vehicle with the insert of FIG. 7 removed, which will be described later, is manufactured by the method S900 for manufacturing a suspension bearing for a compact vehicle of FIG. 2.

In addition, the method of manufacturing a suspension bearing for a compact vehicle (S900), as shown in FIG. 2, includes a first injection molding step (S910), a first transfer step (S920), a second injection molding step (S930), and a second transfer step. It consists of (S940), the third injection molding step (S950), and the vision inspection step (S960).

3 is a perspective view showing a body manufactured in the first injection molding step of FIG. 2, and FIG. 4 is a side view of FIG. 3.

The first injection molding step (S910) of FIG. 2 is the body of FIGS. 3 and 4 through the first injection molding in which the composite material 910 manufactured by FIGS. 8 to 10 to be described later is injected into the cavity of the first mold apparatus. (4) is prepared.

In addition, the body 4, as shown in Figs. 3 and 4, a cylindrical body housing 41 with an upper and lower part open, and an extension part extending outwardly from the upper end of the body housing 41 and connected along an arc ( 43), and a protruding plate 45 formed in a hollow cylindrical shape having an inner diameter larger than that of the body housing 41 and connected to the upper surface of the expansion part 43.

In addition, when the body housing 41 is installed, the piston rod of the shock absorber and the bumper rubber are inserted into the inner opening.

In addition, since the body housing 41 does not have an insert installed therein, since the load of the entire product can be effectively reduced, the efficiency of operation and installation can be increased, and the deterioration of performance due to the removal of the insert is shown in FIGS. 8 to 10 to be described later. It was to be improved through the composite material manufacturing method (S1).

The extension 43 is formed to extend outward from the outer peripheral surface of the body housing 41.

In addition, a first sealing body insertion groove 431 in which the first sealing body 51 of FIG. 5 to be described later is installed is formed on an upper surface adjacent to the outer edge of the extension part 43.

In addition, a second sealing body insertion groove 433 in which the second sealing body 53 of FIG. 5 to be described later is installed is formed in the inner edge of the upper surface formed on the inner side of the protrusion plate 45 of the expansion part 43.

In addition, in the area where the upper surface formed on the inner side of the protruding plate 45 of the expansion part 43 and the inner circumferential surface of the protruding plate 45 are connected, the bearing balls B of FIG. 7 to be described later are seated. It is formed at intervals along an arc.

The body 4 configured as described above is eco-friendly by first injection molding using a carbon fiber composite material prepared by the polymer material mixing step (S70) of FIG. 8 to be described later or a composite material in which PA66 is mixed with a CNT composite material. At the same time, performance such as impact resistance, tensile strength and impact strength can be improved, and the load of the entire product can be significantly reduced as the insert inside is removed.

The first transfer step (S920) of FIG. 2 is a step of transferring the body of FIG. 3 injection-molded by the first injection molding step (S910) to a secondary mold apparatus applied to the second injection molding step (S930), In detail, known transfer means such as a conveyor belt may be applied.

In the second injection molding step (S930), after inserting the body 4 transferred through the first transfer step (S920) into the cavity of the secondary mold apparatus, the body 4 is described later through the second injection molding. The sealing body 5 of FIG. 5 is joined.

5 is a perspective view showing an injection-molded product in the second injection molding step of FIG. 2.

As shown in FIG. 5, the second injection product 920 is coupled with the first sealing body 51 into the first sealing body insertion groove 431 of the body 4 and the second sealing body of the body 4 The second sealing body 53 is coupled to the insertion groove 433.

At this time, the sealing body 5 blocks foreign matter or moisture flowing into the outer gap and the inner gap between the expansion part 4 of the body 4 of FIG. 6 and the cover (not shown), which will be described later. Due to the inflow of moisture, durability decreases, noise is generated, and lifespan is shortened.

The second transfer step (S940) is a step of transferring the second injection product 920 of FIG. 5 injection-molded through the second injection molding step (S940) to a third mold apparatus applied to the third injection molding step (S950) to be.

In the third injection molding step (S950), the second injection product 920 transferred through the second transfer step (S940) is inserted into the cavity of the third mold device, and then the second injection product 920 through the third injection molding process. ) To combine the dumper.

6 is a perspective view showing a third injection product manufactured by the third injection molding step of FIG. 2.

As shown in FIG. 6, the 3rd injection product 930 is coupled with a dumper 7 to surround the outer edge of the extension 43 to the lower end of the body housing 41. That is, the dumper 7 is manufactured integrally with the body 4 through the third injection molding step (S950), thereby simplifying assembly and installation and being firmly coupled to the body 4.

The vision inspection step 60 of FIG. 2 is a step of performing a vision inspection of the third injection molding 930 injection-molded through the third injection molding step S950.

At this time, since vision inspection is a technique commonly used in various process lines, detailed descriptions will be omitted.

7 is a perspective view showing a suspension bearing for a compact vehicle according to an embodiment of the present invention.

The suspension bearing 1 for a compact vehicle according to an embodiment of the present invention includes a body 4, a sealing body 5 and a dumper 7 of FIGS. 3 to 7 described above.

In addition, the medium-sized vehicle suspension bearing (1) is formed in the shape of a circular band whose diameter decreases toward the top and bearing balls (B) that are respectively seated in the mounting grooves (433) of the body (4). Ball-shaped blocking holes are formed and the bearing cage 9 is installed so that blocking holes are disposed on the outside of the bearing balls (B) seated in the mounting grooves 433 of the expansion part 43 of the body 4 Include. At this time, a cover (not shown) may be installed on the upper portion of the expansion part 43. At this time, since the cover (not shown), the ball bearings (B), and the bearing cage 9 are techniques commonly used in suspension bearings, detailed descriptions will be omitted.

In addition, the blocking holes of the bearing cage 9 are formed to have a size smaller than the diameter of the bearing balls B, thereby preventing the bearing balls B from being separated.

Meanwhile, a method of manufacturing a composite material injected into the body injection molding of the present invention will be described.

In general, carbon nanotubes (CNTs) are a kind of carbon allotrope composed of carbon such as diamond and fullerene, and a graphite sheet in which one carbon forms a hexagonal shape with another carbon atom and is bonded is cylindrical. It is a material that forms a tube-shaped material. Depending on the angle and shape of the graphite surface, it can be divided into armchair type, zigzag type, and chiral type, and depending on the number of walls of the graphite surface, single wall carbon nano tube (SWCNT), double wall carbon nano tube (DWCNT). tube) and MWCNT (Multiple wall carbon nano tube). CNTs have a different energy gap depending on their diameter, have a large aspect ratio of horizontal and vertical length, and have a quasi-one-dimensional structure, so they exhibit a peculiar quantum effect.These CNTs have a tensile strength of more than 100 times compared to steel. At the same time, it has an electrical conductivity of 1,000 times or more compared to a copper wire, and is widely used as a variety of electrode materials due to the advantage of having a thermal conductivity of 6000W/mK.

FIG. 8 is a process flow chart showing a method of manufacturing a composite material injected in the first injection molding step of FIG. 2 and used as a material for a body.

The composite material manufacturing method (S1) of FIG. 8 1) increases the dispersibility and increases the CNT content, thereby reducing the surface electrical resistance to 1Ω/□ or less to maximize electrical conductivity, and 2) improving dimensional safety and injection It is intended to be suitable for use for injection molding, and 3) excellent electrical conductivity because it does not contain a separate metal, and to remarkably solve the problem of deteriorating performance due to corrosion when using metal in the prior art.

In addition, the composite material manufacturing method (S1) of the present invention, as shown in Figure 8, the dispersion composition manufacturing step (S10), the dispersion manufacturing step (S20), carbon fiber or CNT preparation step (S30), coating step (S40) , Moisture evaporation step (S50), compression and pelletizing step (S60), polymer material mixing step (S70), PA66 mixing step (S80).

The dispersion composition manufacturing step (S10) is a step of preparing a water-dispersible acrylic anionic resin, which is a dispersion composition.

In addition, in the dispersion composition manufacturing step (S10), polyethylene glycol, acrylic acid, benzene, and sulfuric acid are sufficiently stirred in a stirrer to prepare an intermediate reaction resin, and acrylic acid, acrylonitrile, distilled water, ammonium persulfate and sodium hydrogen sulfide are added to the intermediate reaction resin. To prepare a water-dispersible acrylic-based anionic resin.

At this time, castor oil may be additionally added to the water-dispersible acrylic-based anionic resin, and castor oil is an acrylic-based anionic resin, which improves heat resistance and increases flexibility, thereby increasing the impact strength of the finally manufactured composite material.

The dispersion preparation step (S20) is a step of preparing a dispersion by mixing the water-dispersible acrylic anionic resin prepared by the dispersion composition preparation step (S10) and distilled water.

In addition, in the dispersion preparation step (S20), the higher the content of the water-dispersible acrylic anionic resin contained in the dispersion, the higher the viscosity of the dispersion, and when the viscosity of the dispersion increases excessively, the dispersion is sprayed in the coating step (S40). When this occurs, there is a problem that the dispersion is not uniformly sprayed onto CNTs or carbon fibers.

In addition, in the dispersion manufacturing step (S20), as the content of the water-dispersible acrylic anionic resin contained in the dispersion decreases, the viscosity of the dispersion decreases together, so that the dispersion is uniformly sprayed onto CNTs or carbon fibers during the coating step (S40). However, the dispersibility of CNTs or tamso fibers decreases.

9 is a block diagram illustrating a dispersion prepared by the dispersion manufacturing step of FIG. 8.

The dispersion preparation step of the present invention optimally contains the composition of the dispersion to solve the above-described problem, and in detail, water-dispersible acrylic anionic resin (11) 5.0 to 10.0% by weight and distilled water (13) 90.0 to 95.0 A dispersion liquid (10) is prepared by mixing% by weight.

Carbon fiber or CNT preparation step (S30) is a step of preparing a conventional CNT or carbon fiber. At this time, the CNT is S single-walled carbon nanotube (SWCNT), double-walled carbon nanotube (DWCNT), multi-walled carbon nanotube (MWCNT, multi-walled carbon nanotube), bundle type. The carbon nanotube (rope carbon nanotube) or a combination thereof may be used, and the carbon nanotube (CNT) has a hexagonal shape made of six carbons connected to each other to form a tube shape, and the multi-walled carbon nanotube (MWCNT) has a plurality of The tubes form a concentric circle shape.

The coating step (S40) is a water-dispersible acrylic-based anionic resin and CNT or carbon fiber by spraying the dispersion (10) prepared by the dispersion manufacturing step (S20) onto the carbon fiber or CNT or carbon fiber by the CNT preparation step (S30). This is a step of coating a water-dispersible acrylic-based anionic resin on CNT or carbon fiber by mixing.

That is, in the present invention, the outer surfaces of the CNT particles or carbon fiber particles are coated with a water-dispersible acrylic-based anionic resin through the coating step (S40), thereby increasing the interfacial adhesion of the CNT particles or CNT or carbon fiber particles.

In addition, the coating step (S40) is a process by spraying a dispersion on CNTs or carbon fibers introduced into a stirrer, and in detail, 98.56 to 99.40% by weight of CNTs or carbon fibers, and 0.60 to 1.44% by weight of a water-dispersible acrylic anion resin. The dispersion is sprayed onto CNTs or carbon fibers so that the% is mixed.

At this time, the water-dispersible acrylic anionic resin is 1) If mixed with less than 0.6% by weight based on solid content, the interfacial adhesion of CNTs or carbon fibers in the compression and pelletizing step (S60) to be described later decreases, as well as CNT pellets or CNT pellets after water evaporation. There is a problem that the volume of carbon fiber pellets is reduced, and 2) if it exceeds 1.44% by weight based on solid content, the interfacial adhesion between CNT particles or carbon fiber particles becomes excessively strong, and the compression and pelletization step (S60) When CNT pellets or carbon fiber pellets are not properly broken, the dispersibility of CNTs or carbon fibers is lowered.

On the other hand, when the dispersion is sprayed, CNTs absorb water and the volume of CNTs is reduced, thereby increasing the apparent density of CNTs, thereby obtaining an effect of increasing the dispersibility of CNTs and water-dispersible acrylic anionic resins.

The water evaporation step (S50) is a step of evaporating the moisture of the mixture mixed by the coating step (S40).

In addition, the water evaporation step (S50) evaporates water by stirring the RPM to 10 or less while the agitator is heated to about 110°C. At this time, if the RPM of the stirrer is more than 10, the adhesion of the CNT is weakened, and thus it is broken or the volume is increased.

Compression and pelletization step (S60) is a step of producing CNT pellets or carbon fiber pellets by compressing the mixture that has passed through the moisture evaporation step (S50) with an extruder.

In addition, in the compression and pelletizing step (S60), the mixture is extruded in a size of 3.0 to 4.0 mm in diameter and 4.0 mm in length using an extruder having a length of a single screw less than 1500 mm. At this time, it is preferable that the screw temperature of the extruder is 110 ~ 130℃, and if the screw temperature is over 130℃, the curing speed of the water-dispersible acrylic anionic resin is accelerated, so that the interfacial adhesion between the CNT or Tanseo fiber and the polymer materials for product molding is reduced. It may be weakened, so set the screw temperature to a temperature lower than 130℃.

As the CNT pellets or carbon fiber pellets produced by the compression and pelletizing step (S60) are pressed during the extrusion process to reduce their volume, the apparent density is higher than the apparent density of CNTs or carbon fibers themselves. Dispersibility is improved. At this time, if the apparent density of CNT pellets or carbon fiber pellets is 0.2g/cc or more, there is a problem in dispersibility, and if it is 0.12g/cc or less, it is difficult to compound a high content.

Accordingly, in the compression and pelletizing step (S60) of the present invention, an environment is created so that the CNT pellets or carbon fiber pellets have an apparent density of 0.12 to 0.20 g/cc.

The polymer material mixing step (S70) is a step of mixing and compounding CNT pellets or carbon fiber pellets, which are extrudates of the compression and pelletizing step (S60), a polymer material for product molding, and other additives. At this time, polypropylene resin, thermoplastic elastomer, etc. may be applied as the polymer material, and since the polypropylene resin has excellent chemical resistance, the chemical resistance of CNT or carbon fiber can be improved.

At this time, the mixture prepared by the high injection jet mixing step (S70) will be referred to as a CNT composite material or a carbon fiber composite material.

In addition, since CNT or carbon fiber itself has a low impact strength, a thermoplastic elastomer is mixed in the polymer material mixing step (S70) to solve this problem. At this time, among the thermoplastic elastomers, styrene-ethylene-butylene-styrene (SEBS) is used, and SEBS has strong acid resistance and alkali resistance, and excellent weather resistance and heat aging resistance, so that the function of CNT or carbon fiber can be improved.

10 is a block diagram showing a CNT composite material or a carbon fiber composite material manufactured by the polymer material mixing step (S70) of FIG.

The CNT composite material or carbon fiber composite material 901 manufactured by the polymer material mixing step (S70) is 10 to 25 weight of the CNT pellet 903 by the compression and pelletizing step (S60) as shown in FIG. %, and 40 to 70% by weight of a polypropylene resin (905) and 5 to 35% by weight of styrene-ethylene-butylene-styrene (SEBS) (907). Although not shown in the drawings, the CNT composite material or the carbon fiber composite material 901 may further contain 0.2% by weight of other additives based on the total weight, and antioxidants, plasticizers, stabilizers, etc. may be applied as other additives. .

At this time, the CNT pellets or carbon fiber pellets 903 have a disadvantage that if the content exceeds 25% by weight, the effect of improving electrical resistance is insufficient, and if the content is less than 10% by weight, the electrical conductivity is poor.

In addition, if the content of SEBS (907) is less than 5% by weight, the impact strength of the final composite material is lowered, and if the content exceeds 35% by weight, the compatibility with the polypropylene resin 905 is reduced. Occurs.

PA66 mixing step (S80) is by mixing and stirring PA66 to the CNT composite material or carbon fiber composite material 901 prepared by the polymer material mixing step (S70), and finally manufacturing a composite material to be applied to the body 4 The impact resistance, tensile strength, and impact strength of the body 4 of FIG. 4 described above were increased.

In addition, in the PA66 mixing step (S80), a composite material is prepared by mixing and stirring 15 to 40% by weight of the CNT composite material or carbon fiber composite material (901) by the polymer material mixing step (S70) and 60 to 85% by weight of PA66. do.

As described above, in the composite material manufacturing step (S1) of the present invention, the mixture prepared by the polymer material mixing step (S70) is formed by pelletizing CNT or carbon fiber through the compression and pelletizing step (S60). In addition to obtaining the effect of improving the dispersibility of the fiber, the CNT or carbon fiber particles are coated with a water-dispersible acrylic anionic resin through the coating step (S40). As the dispersibility of CNT or carbon fiber particles is improved due to the occurrence of ionic repulsion, the effect of dispersing CNT or carbon fiber particles evenly and effectively with the polypropylene resin and the thermoplastic elastomer is obtained.

In addition, since the CNT or carbon fiber particles are coated with a water-dispersible acrylic anion to modify the surface, the interfacial adhesion between the CNT or carbon fiber particles and the polypropylene resin and thermoplastic elastomer is also increased.

Hereinafter, a method for manufacturing a CNT material (S1), which is an embodiment of the present invention, will be described in more detail by way of examples. In addition, the following examples are for the purpose of explanation and do not limit the scope of protection of the present invention.

Table 1 shows examples and comparative examples of the present invention.

CNT composite material PA66 Fiberglass
Example 1 15 85 - Example 2 30 70 - Example 3 40 60 - Comparative Example 1 - 70 30 Comparative Example 2 5 95 - Comparative Example 3 50 50 -

*Unit is weight%.

[Example 1]

15% by weight of CNT composite material;

Composites containing 85% by weight of PA66.

At this time, the CNT composite material is a mixture prepared by the polymer material mixing step (S70) of FIG. 8 described above.

[Example 2]

30% by weight of CNT composite material;

Composite material containing 70% by weight of PA66.

[Example 3]

40% by weight of CNT composite material;

Composite material containing 60% by weight of PA66.

[Comparative Example 1]

15% by weight of glass fibers;

A composite material comprising 85% by weight of PA66;

[Comparative Example 2]

5% by weight of CNT composite material;

Composite material containing 95% by weight of PA66.

[Comparative Example 3]

50% by weight of CNT composite material;

Composites containing 50% by weight of PA66.

Table 2 shows the measured values of the compression test test according to the Examples and Comparative Examples of Table 1.

Compressive strength (kgf/mm ² ) Example 1 790.000 Example 1 855.300 Example 1 870.900 Comparative Example 1 737.200 Comparative Example 2 740.300 Comparative Example 31 762.600

In Examples 1 to 3, as the CNT composite material 901 is contained in an appropriate content of 15 to 40% by weight, the compressive strength is '790.000kgf/mm ² ', '855.300kgf/mm ² ', '870.900kgf/mm ² It can be seen that all were measured with a compressive strength of more than '790.000kgf/mm ² '.

In Comparative Example 1, it can be seen that as the glass fiber is contained instead of the CNT composite material 901, the compressive strength of '737.200kgf/mm ² ', which is low compared to the Examples, is measured.

In Comparative Example 2, the compressive strength was measured to be '740.300kgf/mm ² ', and as the content of the CNT composite material 901 contained 5% by weight less than the appropriate content of 15 to 40% by weight, compared with the examples. It can be seen that the compressive strength has decreased.

In Comparative Example 3, the compressive strength was measured as '762.600kgf/mm ² ', and as the content of the CNT composite material 901 contained 50% by weight exceeding the appropriate content of 15 to 40% by weight, the dispersibility was rather lowered. It can be seen that the compressive strength is low compared to the examples.

As described above, since the suspension bearing 1 for a compact vehicle according to an embodiment of the present invention can exhibit a desired performance without installing an insert inside the body housing of the body, it is excellent in performance and can reduce the load of the product.

In addition, in the present invention, the suspension bearing 1 for a compact vehicle is injection-molded with a material in which the housing is made of a mixture of PA66 and a carbon fiber composite material or CNT composite material, thereby remarkably improving performance such as impact resistance, tensile strength and impact strength while being friendly. It can be increased, and the specific gravity can be reduced.

In addition, the suspension bearing 1 for a compact vehicle of the present invention is manufactured in a series of processes through the third injection molding of the body, sealing body, and dumper, thereby shortening the process time and maximizing the production amount, and at the same time, significantly reducing the work cost. .

In addition, in the suspension bearing 1 for a compact vehicle of the present invention, by installing a sealing body between the body and the dumper through secondary injection molding, it is possible to thoroughly block the inflow of foreign substances and moisture from the outside by the sealing body.

1: Suspension bearing 4: Body 5: Sealing body
7: Dumper 9: Bearing cage B: Bearing ball
41: body housing 43: expansion part 51: first sealing body
53: second sealing body 431: first sealing body insertion groove
433: 2nd sealing body insertion groove
S1: composite material manufacturing method S10: dispersion composition manufacturing step
S20: dispersion manufacturing step S30: carbon fiber or CNT preparation step
S40: Coating step S50: Water evaporation step
S60: Compression and pelletization step S70: Polymer material mixing step
S80:PA66 mixing stage
S900: Manufacturing method of suspension bearings for small vehicles
S910: 1st injection molding step S920: 1st transfer step
S930: 2nd injection molding step S940: 2nd transfer step
S950: 3rd injection molding step S960: Vision inspection step

Claims (7)

In the suspension bearing installed in the vehicle suspension (Suspension) comprising a body and bearing balls (B):
The body
A body housing formed in a cylindrical shape with upper and lower portions opened, and through which a piston rod of a shock absorber passes through the upper and lower openings;
An extension part formed to extend vertically outward to the upper end of the body housing and connected along an arc;
And a protruding plate formed in a hollow cylindrical shape having an inner diameter larger than that of the body housing and connected to the upper surface of the expansion part,
At a point where the upper surface of the extension part formed on the inner side of the protruding plate and the inner circumferential surface of the protruding plate are connected, the seating grooves in which the bearing balls B are seated are repeatedly formed along an arc,
The body is made of a synthetic material,
The method of manufacturing the composite material (S1)
A dispersion preparation step of preparing a dispersion by mixing a water-dispersible acrylic anionic resin with distilled water;
A coating step of injecting CNT (carbon nanotube) or carbon fiber into a stirrer, and then spraying the dispersion obtained by the dispersion preparation step to coat CNT or carbon fiber with a water-dispersible acrylic anionic resin;
A moisture evaporation step of evaporating the moisture of the mixture by the coating step;
A compression and pelletizing step of extruding the mixture obtained by the water evaporation step with an extruder to produce CNT pellets or carbon fiber pellets;
A polymer material mixing step of mixing and compounding CNT pellets or carbon fiber pellets by the compression and pelletizing step and a polymer material to prepare a CNT composite material or a carbon fiber composite material;
Including a PA66 mixing step of preparing the mixed material by mixing and stirring the CNT composite material or carbon fiber composite material by the polymer material mixing step with PA66,
The polymer material mixing step
CNT composite material or carbon fiber composite material by mixing 10 to 25% by weight of CNT pellets or carbon fiber pellets, 40 to 70% by weight of polypropylene resin, and 5 to 35% by weight of styrene-ethylene-butylene-styrene (SEBS) Suspension bearing, characterized in that to manufacture a. The method of claim 1, wherein the suspension bearing further comprises a first sealing body, a second sealing body, and a dumper,
A first sealing body insertion groove is formed on an upper surface adjacent to the outer edge of the expansion portion to be connected along an arc, and a second sealing body insertion groove is formed on an inner edge of the upper surface of the expansion portion formed on the inside of the protruding plate. Is formed to be connected,
The first sealing body is coupled to the first sealing body insertion groove of the expansion part,
The second sealing body is coupled to the second sealing body insertion groove of the expansion part,
The dumper is
Suspension bearing, characterized in that it is installed to surround the outer side from the lower surface of the extension to the lower end of the body housing. The method of claim 2, wherein the body is manufactured through primary injection molding by a primary mold device,
The first sealing body and the second sealing body are manufactured through secondary injection molding by a secondary mold apparatus in which the primary injection molded product is disposed inside a cavity,
The dumper is a suspension bearing, characterized in that it is manufactured through a third injection molding by a third mold apparatus in which the second injection molding is arranged inside the cavity. delete The suspension bearing of claim 3, wherein in the mixing step of PA66, 15 to 40 wt% of the composite material and 60 to 85 wt% of PA66 are mixed and stirred. delete The method of claim 5, wherein the coating step
The dispersion is sprayed on the CNT so that 98.5 to 99.40% by weight of CNT or carbon fiber and 0.60 to 1.44% by weight of a water-dispersible acrylic anionic resin are mixed,
The dispersion preparation step
Suspension bearing, characterized in that the dispersion is prepared by mixing 5.0 to 10.0% by weight of a water-dispersible acrylic anionic resin (11) and 90.0 to 95.0% by weight of distilled water (13).

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