KR102429604B1 - Apparatus for reducing noise of pra using sound absorbing damper - Google Patents

Abstract

According to one disclosure, the housing of the PRA (Power Relay Assembly) included in the electric vehicle, the first wire including the relay that is included in the housing and connects the negative voltage between the battery and the inverter, the housing The second wire is included and includes a relay for connecting a positive voltage between the battery and the inverter, based on the charge/discharge operation of the battery, open or short the relay of the first wire and the relay of the second wire Provide a device for reducing the noise of the PRA using a sound-absorbing plate, comprising a control unit for controlling the sequence of can do.

Description

A device for reducing the noise of PRA by using a sound-absorbing plate {APPARATUS FOR REDUCING NOISE OF PRA USING SOUND ABSORBING DAMPER}

The present invention relates to an apparatus for reducing the noise of a PRA using a sound-absorbing plate. More specifically, an apparatus for reducing the piezoelectric noise of a PRA (Power Relay Assembly) by using an insulating sound-absorbing damper in order to reduce noise generated according to the operation of an electric vehicle is disclosed according to one disclosure of the present invention.

Recently, the development and dissemination of eco-friendly vehicles that reduce fuel efficiency and minimize carbon dioxide emissions are being politicized at home and abroad. Accordingly, interest in HEV (Hybrid Electric Vehicle) and EV (Electric Vehicle) vehicles is increasing.

An electric vehicle (EV) is a vehicle that mainly uses the power of a battery to drive an AC or DC motor to obtain power. It is largely classified into a battery-only electric vehicle and a hybrid electric vehicle. It drives the motor and recharges it when power is exhausted. In hybrid electric vehicles, the engine is operated to generate electricity to charge the battery, and this electricity can be used to drive the electric motor to move the vehicle.

In an electric vehicle, the PRA (Power Relay Assembly) is a device for controlling the on-off operation of a relay that receives power applied from a battery that supplies power to an electric vehicle and drives to supply and cut off power to the load stage.

When the brake was operated while the electric vehicle was running, noise was generated, and as a result of analyzing the waveform and frequency of this noise, it was found that the main cause of the noise was the piezoelectric noise of the PRA through which two wires pass. That is, the potential difference between the two wires inside the PRA causes a dimensional change due to the piezoelectric effect in the dielectric existing between the wire and the wire, and this dimensional change becomes a noise that vibrates the air. Accordingly, the need for a method for reducing noise generated during the operation of an electric vehicle has increased.

Korean Patent Publication No. 10-2016-0148933 (published on December 27, 2016) Korean Patent Publication No. 10-2020-0018815 (published on February 20, 2020)

Technical problem according to an embodiment of the present invention provides an apparatus for reducing switching noise due to the piezoelectric effect of the PRA using a sound absorbing plate (damper) in order to solve the above problems.

According to one disclosure, the housing of the PRA (Power Relay Assembly) included in the electric vehicle, the first wire including the relay that is included in the housing and connects the negative voltage between the battery and the inverter, the housing The second wire is included and includes a relay for connecting a positive voltage between the battery and the inverter, based on the charge/discharge operation of the battery, open or short the relay of the first wire and the relay of the second wire Provide a device for reducing the noise of the PRA using a sound-absorbing plate, comprising a control unit for controlling the sequence of can do.

A PRA (Power Relay assembly) that includes a battery for accumulating and supplying high voltage operating power according to another disclosure, a plurality of relays, and switching so that the operating power of the battery is supplied to the vehicle according to whether the plurality of relays operate, a plurality of An inverter that includes a switching element and converts the energy received from the PRA into AC power, a motor driven by receiving the AC power converted from the inverter, and the dielectric between two wires included in the PRA by the piezoelectric effect It may include an insulating sound-absorbing plate to reduce the generated noise.

According to another disclosure, a first wire including a first main relay connecting a negative voltage between a battery and an inverter, and a second main connecting a positive voltage between the battery and the inverter A second wire including a relay and a pre-charge relay connected in parallel with the second main relay, and a controller for controlling the relay of the first wire and the relay of the second wire based on the charging/discharging operation of the battery and an insulating sound-absorbing plate inserted between the first electric wire and the second electric wire to reduce noise caused by the piezoelectric effect generated between the first electric wire and the second electric wire, wherein the insulating sound-absorbing plate includes the first electric wire and the second electric wire It is characterized in that it is made of a sound-absorbing material that absorbs vibrations generated by the operation of the relay included in the .

According to the present invention according to one disclosure according to the present invention, it is possible to effectively reduce the noise generated by the PRA during the operation of the electric vehicle by changing the mass, structure, etc. of the PRA using the sound absorbing plate.

According to one disclosure according to the present invention, it provides an effect of reducing noise generated during driving of a vehicle by using an insulating sound-absorbing plate.

1 is a block diagram schematically illustrating a configuration for controlling an electric vehicle according to an embodiment.
2 is a view for explaining a structure of a PRA for connecting a battery and a motor according to one disclosure.
3 is a view for explaining the structure of the PRA before the resonant frequency improvement according to the disclosure.
4 is a view for explaining a PRA including a device for reducing the noise of the PRA using a sound-absorbing plate according to one disclosure.
5 is a view for explaining the structure of the PRA through the sound-absorbing material coating method according to the disclosure.

Terms used in this specification will be briefly described, and an embodiment of the present invention will be described in detail.

The terms used in this specification have been selected as currently widely used general terms as possible while considering the functions in the present invention, which may vary depending on the intention or precedent of a person skilled in the art, the emergence of new technology, and the like. In addition, in a specific case, there is a term arbitrarily selected by the applicant, and in this case, the meaning will be described in detail in the description of the corresponding invention. Therefore, the terms used in this specification should be defined based on the meaning of the term and the overall content of the present invention, rather than the name of a simple term.

In the entire specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated. In addition, terms such as "...unit" and "module" described in the specification mean a unit that processes at least one function or operation, which may be implemented as hardware or software, or a combination of hardware and software. .

Hereinafter, with reference to the accompanying drawings, the embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the embodiments of the present invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Hereinafter, the apparatus 100 for reducing the noise of the PRA using the sound absorbing plate will be abbreviated as the PRA noise reduction apparatus 100 .

1 is a block diagram schematically illustrating a configuration for controlling an electric vehicle according to an embodiment.

As shown in FIG. 1 , the electric vehicle according to the present invention may include a battery 140 , a PRA 120 , a noise control unit 110 , a noise reduction unit 130 , an inverter 160 , and a motor 170 . can In addition, although not shown in the drawings, it includes a motor 170 control unit (MCU) for controlling the motor 170 and a vehicle control unit (ECU) for controlling overall according to vehicle driving and operation.

Here, the PRA noise reduction device 100 includes a battery 140 for accumulating and supplying high voltage operating power, and a plurality of relays. (Power Relay assembly) 120, an inverter 160 that includes a plurality of switching elements and converts energy received from the PRA into AC power, a motor 170 driven by receiving AC power converted from the inverter, and a PRA It may include a noise reduction unit 130 that changes the natural vibration frequency of the PRA so as not to match the frequency of the piezoelectric noise caused by the piezoelectric effect generated between the two wires included therein.

An electric vehicle using charged electricity as an operating power source operates with the battery 140 including at least one battery cell as described above, and is provided by receiving power from the outside at a predetermined charging station or vehicle charging facility or at home. The battery 140 is charged.

The battery 140 is composed of a plurality of battery cells and stores high voltage electric energy.

The battery management unit, that is, a battery management system (BMS) checks the remaining capacity of the battery 140 to determine whether charging is necessary, and performs management according to supplying the charging current stored in the battery to each part of the electric vehicle.

In this case, when the BMS is charged and used, the voltage difference between cells in the battery is evenly maintained, and the battery is controlled not to be overcharged or overdischarged, thereby extending the lifespan of the battery.

In addition, the BMS enables the vehicle to run for a long time through management of current use, and includes a protection circuit against the supplied current.

When the BMS is connected to an electric charging station through a connection terminal or a connection circuit provided in the electric vehicle, the BMS applies the supplied charging current to the battery 140 to charge the battery. In this case, the electric vehicle further includes a charger for charging the battery 140 using the charging current, or a converter and an inverter for converting necessary power.

The motor 170 controller MCU generates a control signal for driving the connected at least one motor 170 according to a control command of the vehicle controller and applies the generated control signal to the motor 170 . In addition, the motor 170 control unit MCU allows the high voltage power charged in the battery 140 to be changed and supplied according to the characteristics of the motor 170 .

The vehicle control unit (ECU) generates and applies a predetermined command to perform a set operation in response to a user input, applies the control, and controls input/output of data to display the operation state.

The vehicle control unit (ECU) manages the battery 140 through the BMS and applies a switching signal to the PRA 120 to control supply of power to a specific location (part) or power cut off.

The vehicle controller may control the driving of the vehicle and determine whether the PRA is normally operated by using the magnitude of the piezoelectric noise generated as the vehicle travels.

According to one disclosure, when the magnitude of the piezoelectric noise is greater than a predetermined range, the vehicle controller diagnoses whether the PRA is operating normally through test control for a plurality of relays, and when the PRA is in the normal operating range, the magnitude of the piezoelectric noise It is possible to change the properties of the noise reduction unit that can reduce the noise level, output a warning message to stop the driving of the vehicle when the PRA is out of the normal operating range, and generate diagnostic information on the failure state of the PRA.

The power relay assembly (PRA) 120 is a switching means for switching a high voltage, and including a plurality of relays and sensors, applies or cuts off the high voltage operating power applied from the battery 140 to a specific position.

In particular, the PRA 120 sequentially controls the relay so that the high voltage operating power is not suddenly supplied when the vehicle is started so that power is stably supplied to the vehicle, and when the vehicle is started off, it sequentially controls the relay to cut off the power supply. .

The PRA 120 is connected to the MCU, the vehicle control unit (ECU), the battery 140, the DC-DC converter (not shown), and the charger (not shown), and switches the relay according to the control signal of the vehicle control unit, and the battery ( 140) is supplied.

The PRA 120 includes a plurality of relays and sensors, in particular, a first main contact relay (-), a second main contact relay (+), and a pre-charge relay. relay) and a current sensor.

The PRA 120 switches the plurality of relays provided as described above according to a signal applied from the vehicle control unit. In particular, the PRA 120 switches a plurality of relays provided in a predetermined order when the vehicle is started or when the vehicle is turned off, so that the high voltage operating power stored in the battery 140 is applied or cut off to each part of the vehicle. .

The noise reduction unit 130 serves to reduce noise generated inside the PRA 120 by preventing amplification of the noise generated in the PRA 120 . More specifically, the noise reduction unit 130 may reduce the switching noise of the PRA 120 by changing the shape and mass of the PRA.

The noise control unit 110 determines the properties and types of the noise reduction unit 130 necessary to reduce noise according to the state information of the PRA 120 .

The noise control unit 110 determines the frequency range of the piezoelectric noise generated as the vehicle travels, determines the frequency range of the range that does not match the natural vibration frequency range of the piezoelectric noise, and sets the natural vibration frequency of the PRA as the frequency range. A property of the noise reduction unit 130 for moving may be determined, and the determined property of the noise reduction unit may be transmitted to the user terminal.

According to one disclosure, the noise control unit 110 may obtain driving information of the vehicle and information about the surrounding state of the vehicle. The driving information and the surrounding state information of the vehicle may be acquired through a sensing unit included inside or outside the vehicle.

According to one disclosure, the noise control unit 110 may determine the type of the noise reduction unit for changing the natural vibration frequency of the PRA, based on the obtained information. The type of the noise reduction unit may be a mass increase or decrease, a sound-absorbing material coating method, or a grid structure installed outside.

According to one disclosure, the noise control unit 110 may determine the properties of the noise reduction unit including at least one of the determined component, weight, and material of the noise reduction unit. That is, it is possible to determine the component, method, mass, and the like of each noise reduction unit.

According to one disclosure, the noise control unit 110 may determine whether the frequency of the piezoelectric noise coincides with the frequency of the piezoelectric noise by predicting the natural vibration frequency of the PRA according to the determined property of the noise reduction unit. Still, if the frequency of the piezoelectric noise and the natural vibration frequency match, the noise is amplified and the noise level can be increased, so the natural vibration frequency of the PRA needs to be changed again.

2 is a view for explaining the structure of the PRA for connecting the battery and the motor 170 according to the disclosure.

The vehicle control unit generates and applies a predetermined signal based on the state information of each connected part, and in particular, applies a switching signal to the PRA 120 in response to the state information of the BMS and the measured current.

At this time, the first main contact relay and the second main contact relay of the PRA 120 are respectively connected to the vehicle control unit by a separate connection line, and each operates according to a switching control signal input from the vehicle control unit, and each relay is turned ON. ), a predetermined voltage is input to the vehicle control unit as a feedback signal accordingly. The vehicle control unit checks whether the first main contact relay or the second main contact relay is in an ON or OFF state according to an input voltage value.

Here, a dimensional change due to the piezoelectric effect may be induced in the electric wire connected to each relay and the dielectric existing between the electric wire, and this dimensional change may cause noise that vibrates air.

3 is a view for explaining the structure of the PRA before the resonant frequency improvement according to the disclosure.

Power stored in the battery 140 may be used to drive the motor 170 to generate power. The battery according to an embodiment of the present invention may be a lithium battery. The battery 140 may be connected to the inverter 160 through the PRA 120 .

The inverter 160 may convert power of the battery to have electrical characteristics required by the motor 170 and transmit it to the motor 170 . The motor 170 may generate power by rotating by the power transmitted through the inverter.

The PRA 120 may include at least one relay. Specifically, the PRA 120 may include a main relay and a pre-charge relay. According to on/off of the main relay, current flows from the battery and is supplied to the inverter, and the motor 170 may be driven. The pre-charge relay may be implemented as a circuit for pre-charging the capacitor of the inverter 160 before the battery and the capacitor of the inverter are connected through the main relay.

When the user inputs a start command to the vehicle, the vehicle controller controls the PRA 120 to pre-charge the capacitor with the pre-charge relay. ) can be supplied.

Hereinafter, the apparatus 100 for reducing the noise of the PRA using the sound absorbing plate will be abbreviated as the PRA noise reduction apparatus 100 .

4 is a view for explaining a PRA including a device for reducing the noise of the PRA using a sound-absorbing plate according to one disclosure.

According to one disclosure, the PRA noise reduction device 100 is included in the housing 121 and the housing 121 of the PRA (Power Relay Assembly, 120) included in the electric vehicle, and is provided between a battery and an inverter. A first wire 122 including a relay for connecting a negative voltage and a second wire 123 including a relay for connecting a positive voltage between the battery and the inverter included in the housing 121 may be included. . In addition, based on the charging/discharging operation of the battery, a control unit for controlling the sequence of opening or shorting of the relay of the first wire and the relay of the second wire, and the first wire 122 and the second wire 123 ) may include a noise reduction unit 130 mounted on the housing to reduce noise caused by the piezoelectric effect.

According to one disclosure, the noise reduction unit 130 of the PRA noise reduction apparatus 100 may include an insulating sound absorbing plate 410 .

The insulating sound absorbing plate 410 according to one disclosure is the frequency range of noise caused by the potential difference between the first wire 122 and the second wire 123 generated according to the operation of the electric vehicle and the shape of the PRA 120 and It may be mounted between the dielectric between the first electric wire 122 and the second electric wire 123 so that the natural vibration frequency range determined by the mass does not match.

The insulating sound-absorbing plate 410 by one disclosure has a melt flow index (MFI) of 12 to 20 g/10min, a polypropylene having a melting point (Tm) of 166 to 168 ° C, a weight ratio of 6:4, and a dispersed phase. It consists of a sheath-core type composite fiber containing a changeable material (PCM) as a core component and a polyester-based polymer as a sheath component and a polyester-based low melting point (LM) elastomer. can

The staple fiber included in the sound absorbing material of the present invention may include a phase change material (PCM). A phase change material (PCM) is a material that repeatedly exhibits heat storage and heat dissipation characteristics that absorb heat while melting when the surrounding temperature rises, and release heat while crystallizing when the surrounding temperature decreases.

According to the disclosure, by using short fibers containing a phase change material (PCM), it is possible to increase energy efficiency by adding a temperature control function as well as a sound absorption effect. It is possible to prevent the sound absorbing material from being hardened and the viscoelasticity lowered, thereby reducing the sound absorbing performance.

Short fibers according to one disclosure may include a polyolefin-based polymer and a phase change material (PCM) dispersed in the polyolefin-based polymer. The polyolefin-based polymer according to one disclosure has excellent compatibility with the phase change material (PCM) and may be included as a main component of short fibers including the phase change material (PCM), and the type thereof is not particularly limited, but more preferably Preferably, it may be one or more polyolefin polymers selected from the group consisting of polyethylene, polypropylene, polyisobutylene, and copolymers thereof, and most preferably, it has excellent physical properties such as abrasion resistance and chemical resistance, and the price is low. It may be polypropylene which is inexpensive and has wide versatility.

Polypropylene according to one disclosure has a melt flow index (MFI) of 10 to 40 g/10min, and more preferably a melting point (Tm) measured by DSC of 160 to 165°C. The lower the melt flow index of polypropylene, the higher the fiber stiffness, chemical resistance, and low elongation, but the lower the viscosity, the worse the processability. Since it is difficult, it is most suitable to have a melt flow index of 10 to 40 g/10 min.

The melting point of the phase change material (PCM) included in the short fibers according to the disclosure may be preferably 5 to 44°C. The melting point of the phase change material (PCM) is preferably within the range in consideration of seasonal factors and the temperature range of a typical vehicle interior, and most preferably may be 21 to 34°C.

The phase change material (PCM) according to one disclosure is more preferably a paraffinic phase change material (PCM) having 14 to 22 carbon atoms among those satisfying the melting point range. Paraffin-based phase change material (PCM) has excellent compatibility with polyolefins and is harmless to the human body. Paraffinic phase change material (PCM) is n-octacoic acid, n-heptaconic acid, n-hexacoic acid, n-tetracosan, n-trichoic acid, n-docosanic acid, n-heneikosan, n-icosan , n-nonadecane, n-octadecane, n-heptadecane, n-hexadecane, n-pentadecane, n-tetradecane, or n-tridecane alone or in a mixed form.

According to one disclosure, the weight ratio of the polyolefin-based polymer and the phase change material (PCM) included in the short fibers may be 9: 1 to 3: 7. When the phase change material (PCM) is included below the range, there may be a disadvantage in the temperature control function is insufficient. There may be disadvantages.

The single fiber according to one disclosure may be a composite fiber obtained by composite spinning using a polyolefin-based polymer and a dispersed phase change material (PCM) as one component. Preferably, it may be a composite fiber such as a sheath-core type or a side by side type, and when forming a sheath-core type composite fiber, a polyolefin-based polymer and The dispersed phase change material (PCM) may be a core component, and may be a sheath-core type composite fiber including a polyester-based polymer as a sheath component. Since the polyester-based polymer included as a sheath component has an interfacial property with the polyolefin-based polymer of the core component, a space is formed between them, which maximizes the formation of an air layer, thereby viscous loss of incident sound energy. The over-dissipation path can be maximized, and the sound absorption performance can be significantly improved. The polyester-based polymer included as a sheath component is not particularly limited as long as it is a general-purpose polyester-based polymer, but more preferably polyethyleneterephthalate, polybutyleneterephthalate, or polytrimethylene It may be in the form of a single or a mixture of terephthalate (Polytrimethyleneterephthalate) and the like.

In the sheath-core type composite fiber, the weight ratio of the core component and the sheath component may be 7:3 to 3:7. When the core component is included below the range, the temperature control function is insufficient, and the size of the space formed between the sheath and the core part is reduced, so there may be disadvantages in that the sound absorption performance is lowered. If it is included in excess, there may be a disadvantage in that the overall properties of the composite spun fiber are deteriorated because the sheath component is too small.

In addition, the sound absorbing material of the present invention may include a binder 　 fibers for partially bonding short fibers containing a plurality of phase change materials (PCM). The binder 　 fiber may use a 　 binder 　 fiber commonly used in manufacturing the fiber structure, and may be used in powder form as well as fibers, and more preferably include a low melting point (LM) elastomer.

Elastomer generally refers to a polymer material with remarkable elasticity, such as rubber, that is, it stretches when it is pulled by applying an external force, and refers to a polymer having a property of returning to its original length when external force is removed. A preferred low melting point (LM) elastomer used in the present invention may exhibit an elastic recovery rate of 50 to 80%. If the elastic recovery factor is less than 50%, the fiber aggregate becomes hard and the flexibility is insufficient, so the sound absorption performance may be lowered. .

In the present invention according to one disclosure, the rebound elastic modulus (ASTM D 3574) of the fibrous structure is increased to 50 to 80% by including the binder 　 fiber of the fiber assembly with a low melting point (LM) elastomer having an elastic recovery factor of 50 to 80%. and, ultimately, the vibration damping ability transmitted into the matrix is improved so that the sound absorption rate and transmission loss can be improved.

The low melting point (LM) elastomer may be a polyester-based, polyamide-based, polystyrene-based, polyvinyl chloride-based, or polyurethane-based elastomer, alone or in a mixed form.

In addition, more preferably, the low melting point (LM) elastomer is dimethyl terephthalate (DMT) and dimethyl isophthalate (DMI) or terephthalic acid (TPA) and isophthalic acid (Isophthalic Acid). : IPA) as an acid component (Diacid) as 1,4-butanediol (1,4-Butanediol: 1,4-BD) and polytetramethyleneglycol (PTMG) as a diol component (Diol) for esterification and polymerization It can be prepared through steps.

It is preferable to prepare a low melting point (LM) elastomer and a general polyester in a weight ratio of 40:60 to 60:40. When the low melting point (LM) elastomer is included in a weight ratio of less than 40, elasticity and low melting point function may be reduced, and if the weight ratio exceeds 60, there is a problem in that the manufacturing cost increases.

The sound absorbing material may include 50 to 80% by weight of short fibers including a phase change material (PCM) and 20 to 50% by weight of binders and fibers. When the content of the short fibers including the phase change material (PCM) is less than 50% by weight, the temperature control function for external temperature changes may be insufficient, whereas the content of the short fibers including the phase change material (PCM) is 80 If it exceeds the weight %, the content of the binder and the fibers becomes less than 20% by weight and it is impossible to maintain sufficient binding force between the fibers. The vibration transmitted to the matrix structure caused by the transmission of sound waves may not be sufficiently attenuated, so the sound absorption coefficient of low frequencies may be lowered. As the binder 　 fiber content is increased to 20 to 50% by weight, the elastic modulus of rebound (ASTM D 3574) is increased to 50 to 80%.

According to one disclosure, the insulating sound plate 410 is made by mixing MB (melt blown) fibers and polyethylene terephthalate short fibers having an average diameter of 3.5 μm to 5 μm in a weight ratio of 3.7: 6.3 to obtain an adhesive strength of 6.8 N/25 mm to 13 N/25mm, and a surface density of 330-360 g/m ² A thermosetting adhesive 38 to 45 g/m It may consist of a coating layer coated with ² .

According to another disclosure, the PRA noise reduction device 100 includes a battery for accumulating and supplying high voltage operating power, a plurality of relays, and switching so that the operating power of the battery is supplied to the vehicle according to whether the plurality of relays are operated. PRA (Power Relay assembly), an inverter that includes a plurality of switching elements and converts the energy received from the PRA into AC power, a motor driven by receiving AC power converted from the inverter, and between two wires included in the PRA It may include an insulating sound plate that is included in the dielectric of the piezoelectric effect to reduce the noise generated.

In addition, to determine the frequency range of the piezoelectric noise generated as the electric vehicle travels, to determine the frequency range in a range that does not match the natural vibration frequency range of the piezoelectric noise, and to move the natural vibration frequency of the PRA to the frequency range It is possible to determine the properties of the insulating sound-absorbing plate.

According to another disclosure, the PRA noise reduction device 100 is a first wire including a first main relay (main relay) for connecting a negative voltage between the battery (battery) and the inverter (inverter), between the battery and the inverter A second wire including a second main relay connecting a positive voltage and a pre-charge relay connected in parallel with the second main relay, a relay of the first wire based on the charging/discharging operation of the battery, and It may include a control unit for controlling the relay of the second wire and an insulating sound-absorbing plate inserted between the first wire and the second wire to reduce noise caused by the piezoelectric effect generated between the first wire and the second wire.

Here, the insulating sound-absorbing plate may be made of a sound-absorbing material that absorbs vibrations generated due to the operation of the relay included in the first wire and the second wire.

5 is a view for explaining the structure of the PRA through the sound-absorbing material coating method according to the disclosure.

The noise reduction unit according to one disclosure may be a sound absorbing material 132 mounted on the outer surface of at least a portion of the PRA.

The sound absorbing material 132 according to one disclosure may wrap the outer surface of the PRA 120 , and may be coated on some or all of the outer surface of the PRA 120 .

Here, the sound absorbing material 132 is a mixture of MB (melt blown) fibers and polyethylene terephthalate short fibers having an average diameter of 3.5 µm to 5 µm in a weight ratio of 3.7: 6.3, and has an adhesive strength of 6.8 N/25 mm to 13 N/25 mm. , a sound-absorbing material containing an areal density of 330 to 360 g/m ² , a pattern layer in which a pattern consisting of convex parts and concave parts is irregularly formed on one surface of the sound absorbing material, and a thermosetting adhesive 38 to 45 g/m ² Coating the upper surface of the pattern layer It may consist of a coating layer.

)인 것을, 바람직하게는 MI가 1,100 ~ 1,400g/10분(230

)인 것을, 더욱 바람직하게는 MI가 1200 ~ 1,380g/10분(230

)인 것을 사용할 수 있는데, 이때, MI가 800g/10분(230

) 미만인 것을 사용하면 멜트블로운 섬유의 섬도가 두꺼워지고 이를 보상하기 위해서 가공 온도를 290

이상 올리면 공정비용 증가와 폴리프로필렌 탄화물 증가로 인한 노즐 교체주기가 짧아지는 문제가 있을 수 있고, 1,500g/10분(230

)을 초과하는 것을 사용하면 용융강도(melt strength)가 약해져서 섬유형성능 저하로 인해 방사중에 샷(shot)의 발생빈도가 증가하는 문제가 있을 수 있으므로 범위 내의 MI를 갖는 것을 사용하는 것이 좋다.The sound absorbing material 132 is a polypropylene-based compound-containing resin used for manufacturing melt blown fibers composed of MB (melt blown) fibers is a polypropylene-based compound (or polypropylene-based compound-containing resin), preferably polypropylene and poly It may include at least one selected from among propylene random copolymers, and more preferably polypropylene. In addition, polypropylene has an MI (melt index) of 800 to 1,500 g/10 min (230

), preferably having an MI of 1,100 to 1,400 g/10 min (230

), more preferably MI of 1200 to 1,380 g/10 min (230

) can be used, where the MI is 800 g/10 min (230

), the fineness of the melt blown fiber becomes thicker, and the processing temperature is increased to 290 to compensate for this.

If it is raised above, there may be problems in that the process cost increases and the nozzle replacement cycle becomes shorter due to the increase in polypropylene carbide, and 1,500 g/10 minutes (230

) is used, melt strength is weakened, and there may be a problem in that the frequency of shots during spinning is increased due to deterioration of fiber forming performance.

~ 290

하에서, 바람직하게는 260

~ 280

하에서 수행하는 것이 좋으며, 이때, 핫 에어 온도가 250

미만이면 폴리프로필렌계 화합물 성분의 섬유의 두께가 두꺼워지기 때문에 섬유집합체 공극률이 저하되고 함유되어 있는 공기량이 상대적으로 줄어들기 때문에 극세섬유와 공기층에 의한 소리에너지의 유동저항 감소효과가 저하될 수 있고, 결과적으로 흡음성능이 저하되는 문제가 발생할 수 있다. 그리고, 핫 에어 온도가 290

를 초과하면 공정비용 증가와 폴리프로필렌 탄화물 증가로 인한 노즐 교체주기가 짧아지는 문제와 폴리프로필렌계 화합물 성분의 섬유가 안정적으로 집속되지 못하고 날리는 현상이 나타날 수 있다.The die and nozzle temperature of melt blown spinning and the hot air temperature are 250

~ 290

under, preferably 260

~ 280

It is recommended to carry out under the hot air temperature 250

If it is less than this, since the thickness of the fiber of the polypropylene compound component becomes thicker, the porosity of the fiber aggregate is lowered and the amount of air contained is relatively reduced, so the effect of reducing the flow resistance of sound energy by the ultrafine fibers and the air layer may be reduced. As a result, there may be a problem that the sound absorption performance is lowered. And, the hot air temperature is 290

If it is exceeded, the problem of shortening the nozzle replacement cycle due to increased process cost and increased polypropylene carbide, and the phenomenon that the fibers of the polypropylene-based compound cannot be stably focused and blown may occur.

In the step of producing the melt-blown composite nonwoven fabric, in the production of the melt blown composite nonwoven fabric composed of two or more types of fibers rather than a single type, the melt blown composite fiber and the polyethylene terephthalate short fiber, a polypropylene-based compound-containing resin and a polyethylene-based compound When the resin-containing resin is melt blown composite spinning with a side-by-side composite spinneret, polyethylene terephthalate short fibers are mixed into the melt blown air stream to be spun through a blowing facility and nozzle, and melt blown composite fibers And by mixing polyethylene terephthalate short fibers, it is possible to manufacture a sound absorbing material.

~ 290

하에서, 바람직하게는 260

~ 280

하에서 수행하는 것이 좋으며, 이때, 핫 에어 온도가 250

미만이면 사이드-바이-사이드 복합섬유의 일부인 폴리프로필렌계 화합물 성분의 섬유의 두께가 두꺼워지기 때문에 섬유집합체 공극률이 저하되고 함유되어 있는 공기량이 상대적으로 줄어들기 때문에 극세섬유와 공기층에 의한 소리에너지의 유동저항 감소 효과가 저하될 수 있고, 결과적으로 흡음성능이 저하되는 문제가 발생할 수 있다. 그리고, 핫 에어 온도가 290

를 초과하면 공정비용 증가와 폴리프로필렌 탄화물 증가로 인한 노즐 교체주기가 짧아지는 문제와 폴리프로필렌계 화합물 성분의 섬유가 안정적으로 집속되지 못하고 날리는 현상이 나타나고, 사이스-바이-사이드 복합섬유 중 다른 사이드를 구성하는 폴리에틸렌계 화합물 성분의 섬유와의 접합성이 떨어져서 복합섬유집합체 구조가 불량해지는 문제가 있을 수 있으므로 온도 범위 내에서 수행하는 것이 좋다.Meltblown composite spinning die and nozzle and hot air temperature 250

~ 290

under, preferably 260

~ 280

It is recommended to carry out under the hot air temperature 250

If it is less than this, the thickness of the fiber of the polypropylene compound component, which is a part of the side-by-side composite fiber, becomes thicker, so the porosity of the fiber aggregate is lowered and the amount of air contained is relatively reduced. The effect of reducing the resistance may be reduced, and as a result, there may be a problem that the sound absorption performance is lowered. And, the hot air temperature is 290

If the value exceeds Since there may be a problem that the composite fiber aggregate structure is poor due to poor bonding properties with the fibers of the polyethylene-based compound component constituting the component, it is better to carry out within the temperature range.

The melt blown composite fiber is a side-by-side type composite fiber, and may contain a polypropylene-based compound and a polyethylene-based compound in a weight ratio of 1: 0.5 to 2, preferably 1: 0.7 to 1.5 by weight, At this time, if the polyethylene-based compound is less than 0.5 weight ratio, there may be a problem of lowering adhesiveness and bulkiness, and if it exceeds 2 weight ratio, there may be a problem in that fineness increases due to radioactive degradation and overall defects in the fiber aggregate increase.

)인 것을, 바람직하게는 MI가 1,100 ~ 1,400g/10분(230

)인 것을, 더욱 바람직하게는 MI가 1200 ~ 1,380g/10분(230

)인 것을 사용할 수 있는데, 이때, MI가 800g/10분(230

) 미만인 것을 사용하면 멜트블로운 섬유의 섬도가 두꺼워지고 이를 보상하기 위해서 가공 온도를 290

이상 올리면 공정비용 증가와 폴리프로필렌 탄화물 증가로 인한 노즐 교체주기가 짧아지는 문제가 있을 수 있고, 1,500g/10분(230

)을 초과하는 것을 사용하면 용융강도(melt strength)가 약해져서 섬유형성능 저하로 인해 방사중에 샷(shot)의 발생빈도가 증가하는 문제가 있을 수 있으므로 범위 내의 MI를 갖는 것을 사용하는 것이 좋다.In the melt blown composite fiber, the polypropylene-based compound (or the polypropylene-based compound-containing resin) may include at least one selected from polypropylene and polypropylene random copolymer, preferably polypropylene. . In addition, polypropylene has an MI (melt index) of 800 to 1,500 g/10 min (230

), preferably having an MI of 1,100 to 1,400 g/10 min (230

), more preferably MI of 1200 to 1,380 g/10 min (230

) can be used, where the MI is 800 g/10 min (230

), the fineness of the melt blown fiber becomes thicker, and the processing temperature is increased to 290 to compensate for this.

If it is raised above, there may be problems in that the process cost increases and the nozzle replacement cycle becomes shorter due to the increase in polypropylene carbide, and 1,500 g/10 minutes (230

) is used, melt strength is weakened, and there may be a problem in that the frequency of shots during spinning is increased due to deterioration of fiber forming performance.

)인 것을, 바람직하게는 MI가 145 ~ 160g/10분(190

)인 것을, 더욱 바람직하게는 MI가 150 ~ 160g/10분(190

)인 것을 사용하는 것이 좋으며, 이때, LLDPE 수지의 MI가 140g/10분(190

) 미만인 것을 사용하면 흐름성이 저하되어 멜트블로운 섬유의 섬도가 두꺼워지는 문제가 있을 수 있고, MI가 160g/10분(190

)을 초과하는 것을 사용하면 방사 중에 멜트블로운 섬유 사절현상이 증가하여 복합 부직포 균제도 제어에 불리한 문제가 있을 수 있다.In addition, in the melt blown composite fiber, the polyethylene-based compound (or polyethylene-based compound-containing resin) is a low-density polyethylene (LDPE, Low Density polyethylene), preferably using a linear low-density polyethylene (LLDPE, Linear Low Density polyethylene) This is advantageous in terms of securing the adhesion of the side-by-side composite fiber to the polypropylene compound. And, the linear low-density polyethylene has an MI (melt index) of 140 to 160 g/10 min (190

), preferably having an MI of 145 to 160 g/10 min (190

), more preferably MI is 150 ~ 160 g / 10 minutes (190

) is recommended, and at this time, the MI of the LLDPE resin is 140 g/10 min (190

), there may be a problem that the flowability is lowered and the fineness of the melt blown fiber is thickened, and the MI is 160 g/10 min (190

), the melt blown fiber yarn breakage increases during spinning, so there may be a problem in controlling the uniformity of the composite nonwoven fabric.

In addition, it is advantageous in terms of securing light weight and adhesiveness of the composite fiber aggregate to use the LLDPE resin having a specific gravity of 0.90 to 0.95, more preferably 0.92 to 0.94.

According to one disclosure, the sound-absorbing material 132 may further include a pressure-sensitive adhesive material formed by coating a thermosetting pressure-sensitive adhesive at 45 to 55 g/m 2 , thereby increasing sound insulation performance.

According to one disclosure, the sound-absorbing material may further include a pressure-sensitive adhesive material formed by coating a thermosetting pressure-sensitive adhesive at an amount of 45 to 55 g/m ² , thereby increasing sound insulation performance.

In addition, the coating layer may include a thermosetting resin represented by the following Chemical Formula 1:

[Formula 1]

here,

a, b, c and d are the same as or different from each other and are each independently an integer from 1 to 100.

The coating layer is formed using a composition including a thermosetting resin represented by Formula 1, a metal oxide, a curing agent, and a solvent.

The metal oxide may be selected from the group consisting of Al ₂ O ₃ , Ta ₂ O ₅ , TiO ₂ , CrO ₂ , HfO ₂ and Y ₂ O ₃ , but is not limited thereto.

The curing agent is a monoamine, and the solvent is ethyl acetate, but the examples are not limited thereto.

Specifically, the composition for forming the coating layer may be included in an amount of 5 to 10 parts by weight of a metal oxide, 1 to 5 parts by weight of a curing agent, and 30 to 50 parts by weight of a solvent based on 100 parts by weight of the thermosetting resin. When used by mixing within the above range, the physical properties of the sound-absorbing material can be increased, and the effect of improving the sound-absorbing performance due to the improvement of the physical properties can be increased.

Formation of the coating layer is chemical vapor deposition (chemical vapor deposition), physical vapor deposition (physical vapor deposition), sputtering (sputtering), vacuum deposition (evaporation), spin-on coating (spin-on coating), dip coating (dip coating) , and other similar deposition techniques may be applied, and any one capable of forming a coating layer may be used without limitation.

The sound absorbing material 132 according to another disclosure may be configured by selecting one or more of a polymer, a piezoelectric material, or a metal implementing a specific high-pitched sound range.

Here, the polymer is PMMA (Poly Methyl MethAcrylate), PUA (Poly Urethane Acrylate), PVA (Poly Vinyl Alcohol), polyester (PET), polypropylene (PP), polycarbonate (PC), polyethylene naphthalate (PEN), polyether ether ketone (PEEK), polymethylpentene (TPX), polyimide (PI), polyether imide (PEI), liquid crystal polymer (LCP), and the like.

In addition, the piezoelectric material may be selected from BaTiO3, KNbO3, Ba2NaNb5O5, LiNbO3, SrTiO3, Pb(ZrTi)O3, Pb2KNb5O15, LiTaO3, BiFeO3, NaxWO3, ZnO, PVDF (Polyvinylidene fluoride), Au, or AgDF (metal). , Al, Cu, Ti, Zn, Fe, Mn, Cr, and the like.

When the incident sound arrives at the sound absorbing material 132 , the incident sound is reflected as reflected sound at an acoustic angle by the sound absorbing material 132 , and a portion is absorbed as an absorbing sound according to the material characteristics of the sound absorbing material 132 . Here, the absorbed sound is mainly a sound of a high frequency.

And, in the case of low-frequency sound, diffuse reflection occurs due to the difference in thickness between the convex and concave portions of the sound absorbing material 132 to increase the sound absorption effect. Due to the principle of being more absorbed in the interior and reflected and diffracted by the convex portion, as a result, diffuse reflection is increased, and thus more low-frequency sounds can be absorbed.

In addition, in this low-sound absorption process, not only diffuse reflection, but also low-pitched sounds or frequencies in a specific sound range are absorbed by changing the material, size, and shape of the pattern made of polymer, piezoelectric material, and metal as described above to adjust the natural frequency of the pattern. It may be configured to

In particular, when the sound absorbing material 132 includes a piezoelectric material, the patterned sound absorbing material has a characteristic of converting physical energy into electrical energy, so it is possible to adjust the sound absorbing effect using this, and in this case, by connecting a predetermined ground electrode, etc. By releasing the accumulated electrical energy, the sound absorption effect can be further increased.

production example

production of sound insulation materials

MB (melt blown) fibers and polyethylene terephthalate short fibers having an average diameter of 3.5 μm to 5 μm are mixed in a weight ratio of 3.7: 6.3, and the adhesive strength is 6.8 N/25 mm to 13 N/25 mm, and the areal density is 330 to 360 g/m ² A sound absorbing material was prepared.

One surface of the sound absorbing material was irregularly formed with a pattern consisting of convex portions and concave portions.

Preparation of coating layer

A thermosetting resin represented by the following Chemical Formula 1, Ta ₂ O ₅ , a monoamine as a curing agent, and ethyl acetate as a solvent were mixed as shown in Table 1 below to prepare a coating composition:

[Formula 1]

Here, a, b, c and d are integers from 1 to 100.

HD1 HD2 HD3 HD4 HD5 thermosetting resin 100 100 100 100 100 Ta ₂ O ₅ One 5 7 10 15 monoamine 0.1 One 3 5 7 menstruum 20 30 40 50 60

(unit parts by weight)

The coating composition was applied to one surface on which the pattern portion of the absorption material was formed and cured to form a coating layer.

Experimental Example 1

Evaluation of the physical properties of sound absorbing materials

As a control, a sound absorbing material without a coating layer was used, and physical properties of the sound absorbing material with a coating layer of HD1 to HD5 were evaluated.

The surface on which the coating layer was formed was cut to a size of 2 cm Х 2 cm (thickness: 2 mm) and left at a temperature of 25° C. and a humidity of 50±5% for 16 hours. Thereafter, the hardness of the sound-absorbing material was measured using a hardness meter (D-type hardness meter).

In addition, after acquiring the highest strength value just before fracture while testing at a speed of 500 mm/min using a universal testing machine (UTM), the slope in the region of 20 to 70% of the strain-Stress curve is calculated using the acquired value to calculate the elasticity The modulus was measured.

The experimental results are shown in Table 2 below.

HD1 HD2 HD3 HD4 HD5 control Hardness (H, shore D) 56.2 57.7 58.5 57.5 56.9 55.5 Elastic modulus (M, N/㎟) 110.3 121.1 135.2 123.1 111 60.6

According to the experimental results, it can be confirmed that the physical properties are significantly different depending on whether the coating layer is formed. In light of the environment of use of the sound-absorbing material, if the physical properties are weak, there is a risk of being easily damaged by an external impact. However, it will be said that damage caused by external force can be prevented by improving the physical properties by forming the coating layer as described above.

Experimental Example 2

Sound absorption performance check

A sound absorbing material without a coating layer was used as the control 1, and a gypsum board having a thickness of 6 mm was used as the control 2, and the sound absorbing performance of the sound absorbing material having a coating layer of HD1 to HD5 was confirmed.

/(59.4 오차범위 1.9)% R.H 조건 하에서 실험을 진행하였다. 본 실험예에서 배후공간을 50mm로 하여 진동수 대비 주파수를 측정하였다.The sound absorption performance was confirmed according to the in-pipe method (KS F 2814), and HM-02 I/O (Scein/S.KOREA) was used, (19.4 error range 0.3)

The experiment was conducted under /(59.4 error range 1.9)% RH condition. In this experimental example, the frequency compared to the frequency was measured by setting the rear space to 50 mm.

The results are shown in Table 3 below.

250 500 750 1000 1250 1500 1750 2000 HD1 0.15 0.75 0.91 0.9 0.91 0.84 0.81 0.80 HD2 0.24 0.73 0.95 0.9 0.83 0.8 0.74 0.72 HD3 0.22 0.85 0.92 0.88 0.81 0.75 0.73 0.71 HD4 0.15 0.75 0.92 0.95 0.91 0.87 0.85 0.83 HD5 0.1 0.4 0.84 0.83 0.81 0.77 0.75 0.7 control group 1 0.25 0.55 0.42 0.4 0.53 0.35 0.33 0.3 control group 2 0.09 0.18 0.3 0.4 0.5 0.61 0.62 0.63

According to the results of Table 3, it can be confirmed that the frequency versus the frequency is measured, indicating a higher sound absorption performance than the control group.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improved forms of the present invention are also provided by those skilled in the art using the basic concept of the present invention as defined in the following claims. belong to the scope of the right.

Claims (7)

housing of PRA (Power Relay Assembly) included in electric vehicle;
a first wire included in the housing and including a relay for connecting a negative voltage between a battery and an inverter;
a second wire included in the housing and including a relay connecting a positive voltage between the battery and the inverter;
a control unit for controlling the sequence of opening or shorting of the relay of the first wire and the relay of the second wire based on the charging/discharging operation of the battery; and
A noise reduction unit inserted and mounted in the housing to reduce noise caused by a piezoelectric effect generated between the first wire and the second wire,
The noise is noise according to a dimensional change caused in the PRA by a potential difference generated by the first wire and the second wire,
The PRA includes a first area through which the first electric wire passes and a second area through which the second electric wire passes,
The noise reduction unit,
It is positioned between the first region and the second region to prevent the potential difference, and includes an insulating material to prevent the potential difference,
A device that reduces the noise of PRA by using a sound-absorbing plate. The method of claim 1,
The noise reduction unit,
Further comprising a sound absorbing material for absorbing vibration generated due to the operation of the relay included in the first wire and the second wire,
The sound-absorbing material further comprises a pressure-sensitive adhesive material made by coating a thermosetting pressure-sensitive adhesive 45 to 55 g / m2,
The thermosetting pressure-sensitive adhesive is a device for reducing the noise of the PRA using a sound-absorbing plate that includes a thermosetting resin of the formula (1).
[Formula 1]

However, a, b, c and d are the same as or different from each other and each independently an integer of 1 to 100. The method of claim 1,
The noise reduction unit,
Polypropylene having a melt flow index (MFI) of 12 to 20 g/10 min, a melting point (Tm) of 166 to 168 ° C, a polyolefin-based polymer having a weight ratio of 6:4, and a dispersed phase change material (PCM) as a core A sound-absorbing plate, characterized in that it is an insulating sound-absorbing plate made of a sheath-core type composite fiber and a polyester-based low-melting point (LM) elastomer comprising a polyester-based polymer as a sheath component. A device that reduces the noise of PRA using 4. The method of claim 3,
The insulating sound-absorbing plate,
MB (melt blown) fibers and polyethylene terephthalate short fibers having an average diameter of 3.5 μm to 5 μm are mixed in a weight ratio of 3.7: 6.3 to obtain an adhesive strength of 6.8 N/25 mm to 13 N/25 mm, and an areal density of 330 to 360 g/m ² Sound absorbing material containing phosphorus;
a pattern layer in which a pattern including convex portions and concave portions is irregularly formed on one surface of the sound absorbing material; and
A device for reducing the noise of PRA using a sound-absorbing plate, characterized in that it consists of a coating layer coated with a thermosetting adhesive 38 to 45 g/m ² on the upper surface of the pattern layer. a battery that stores and supplies high voltage operating power;
a power relay assembly (PRA) including a plurality of relays and configured to switch operation power of the battery to be supplied to a vehicle according to whether the plurality of relays operate;
an inverter including a plurality of switching elements and converting the energy received from the PRA into AC power;
a motor driven by receiving AC power converted from the inverter; and
Including an insulating sound-absorbing plate included in the dielectric between the two wires included in the PRA to reduce noise generated by the piezoelectric effect,
The noise is noise according to a dimensional change caused in the PRA by a potential difference generated by the first wire and the second wire,
The PRA includes a first area through which the first electric wire passes and a second area through which the second electric wire passes,
The insulating sound-absorbing plate,
It is positioned between the first region and the second region to prevent the potential difference, and includes an insulating material to prevent the potential difference,
A device that reduces the noise of PRA by using a sound-absorbing plate. 6. The method of claim 5,
The insulating sound-absorbing plate,
Further comprising a sound absorbing material for absorbing vibration generated due to the operation of the relay included in the first wire and the second wire,
The sound-absorbing material further comprises a pressure-sensitive adhesive material made by coating a thermosetting pressure-sensitive adhesive 45 to 55 g / m2,
The thermosetting pressure-sensitive adhesive is a device for reducing the noise of the PRA using a sound-absorbing plate that includes a thermosetting resin of the following formula (1).
[Formula 1]

However, a, b, c and d are the same as or different from each other and each independently an integer of 1 to 100. a first wire including a first main relay connecting a negative voltage between the battery and the inverter;
a second wire including a second main relay connecting a positive voltage between the battery and the inverter and a pre-charge relay connected in parallel with the second main relay;
a controller for controlling the relay of the first wire and the relay of the second wire based on the charging/discharging operation of the battery; and
An insulating sound-absorbing plate inserted and mounted between the first wire and the second wire to reduce noise caused by the piezoelectric effect generated between the first wire and the second wire,
The insulating sound-absorbing plate is characterized in that it is made of a sound-absorbing material that absorbs vibrations generated due to the operation of the relay included in the first and second wires,
The sound absorbing material,
Further comprising a pressure-sensitive adhesive material made by coating a thermosetting pressure-sensitive adhesive at 45 to 55 g / m2,
The thermosetting pressure-sensitive adhesive is a device for reducing the noise of the PRA using a sound-absorbing plate that includes a thermosetting resin of the formula (1).
[Formula 1]

However, a, b, c and d are the same as or different from each other and each independently an integer of 1 to 100.

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