KR20220010811A - Method and apparatus for automatically searching for optimal wireless charging position - Google Patents

Abstract

According to the disclosure, an apparatus for reducing noise caused by braking comprises: a battery for storing and supplying high-voltage operating power; a power relay assembly (PRA) which includes a plurality of relays and switches to supply the operating power of the battery to a vehicle according to an operation state of the plurality of relays; an inverter which includes a plurality of switching elements and converts the energy received from the PRA into alternative current power; a motor which is driven by receiving the alternative current power converted from the inverter; and a noise reducing unit which changes a natural vibration frequency of the PRA not to match a frequency of piezoelectric noise by piezoelectric effect generated between two wires included in the PRA. According to the present invention, the natural vibration frequency of the PRA is changed to reduce switching noise caused by piezoelectric effect of the PRA.

Description

A device for reducing noise caused by driving a brake {Method and apparatus for automatically searching for optimal wireless charging position}

An apparatus for reducing noise by changing a natural vibration frequency of a power relay assembly (PRA) is disclosed in order to reduce noise generated by driving a brake according to one disclosure.

Electric vehicles are being actively researched in that they are the most promising alternatives to solve future automobile pollution and energy problems.

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 the 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.

The driving part of the electric vehicle is connected to the inverter with the motor, and the inverter is connected to the battery through a PRA (Power Relay Assembly). If the brake is applied while the electric vehicle is running, noise is generated while the speed of the electric vehicle is reduced. This noise is caused by the potential generated between the two wires inside the PRA causing a dimensional change due to the piezoelectric effect in the dielectric between the wire and the wire, and the noise can be further amplified due to the natural vibration frequency generated by the PRA have.

Korean Patent Publication No. 10-2003-0052357 (published on June 27, 2003) Korean Patent Publication No. 10-2020-0018815 (published on February 20, 2020)

Technical problem according to one disclosure is to provide an apparatus and method for reducing the switching noise due to the piezoelectric effect of the PRA by changing the natural vibration frequency of the PRA in order to solve the above problems.

According to one disclosure, as an apparatus for reducing noise caused by driving a brake, the apparatus includes a battery for accumulating and supplying high voltage operating power, and a plurality of relays, and depending on whether the plurality of relays operate, the operating power of the battery is changed. A PRA (Power Relay assembly) that switches to be supplied to a vehicle, an inverter that includes a plurality of switching elements and converts energy received from the PRA into AC power, a motor driven by receiving AC power converted from the inverter, and inside the PRA It may include a noise reduction unit for changing 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 included wires.

According to the present invention according to one disclosure, it is possible to effectively reduce noise generated due to the operation of the brake while the vehicle is being driven.

According to one disclosure, by adjusting the natural vibration frequency of the PRA in various ways, it is possible to reduce the noise of the vehicle in a manner suitable for the current state of the vehicle.

1 is a block diagram schematically illustrating a configuration for controlling an electric vehicle according to an exemplary 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 the structure of a PRA through a mass change method according to one disclosure.
5 is a view for explaining the structure of the PRA through the sound absorbing material co-v method according to the disclosure.
6 is a view for explaining a PRA structure in which a resonant frequency is improved by using a rib structure according to one 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, but these 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 element, this means that other elements may be further included, rather than excluding other elements, 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 of ordinary skill in the art can easily implement them. However, the present invention may be embodied in several 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 device 100 for reducing noise caused by driving the brake will be abbreviated as the noise reducing device 100 .

1 is a block diagram schematically illustrating a configuration for controlling an electric vehicle according to an exemplary 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 noise reduction device 100 includes a battery 140 for accumulating and supplying high voltage operating power, and a plurality of relays, and a PRA ( 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 that is driven by receiving AC power converted from the inverter, and the inside of the 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 in the PRA.

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, vehicle charging facility, or 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, ie, 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 life 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 supplied charging current is applied 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 control unit (MCU) generates a control signal for driving the connected at least one motor 170 , 170 according to a control command of the vehicle control unit, and applies the generated control signal to the motors 170 and 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, to output a warning message to stop the driving of the vehicle when the PRA is out of the normal operating range, and to generate diagnostic information about the PRA's fault state.

A power relay assembly (PRA) 142 is a switching means for switching a high voltage, and includes a plurality of relays and sensors, and applies or blocks high voltage operation 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 acquire driving information of the vehicle and information about the surrounding state of the vehicle. The driving information and 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 a property 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 matches the natural vibration frequency, 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 control unit controls the PRA 120 to pre-charge the capacitor with the pre-charge relay, and then, if it is determined that normal operation is performed, then uses the main relay to convert the voltage to the inverter 160 ) can be supplied.

4 is a view for explaining the structure of a PRA through a mass change method according to one disclosure.

According to one disclosure, the noise reduction unit may be implemented in the form of a mass addition module 131 that changes a natural vibration frequency generated when the PRA is driven by adding a mass in a predetermined range to the PRA 120 .

The mass adding module 131 according to one disclosure may change the mass of the PRA 120 to change the natural vibration frequency of the PRA 120 itself. The mass adding module 131 according to one disclosure adds an appropriate mass to the PRA 120 so that the natural vibration frequency of the piezoelectric noise generated inside the PRA 120 does not match the natural vibration frequency of the PRA 120 .

The mass adding module 131 may be manufactured as a divisible mass, and an appropriate mass may be added to the PRA 120 according to circumstances. An appropriate mass added to the PRA 120 may be determined by the noise control unit 110 .

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 a part 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 and concave portions 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 is 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

), 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, so it is better to use a material having an MI within the range.

~ 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 and hot air temperature of melt blown spinning 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 single fibers, a melt blown composite fiber and a polyethylene terephthalate short fiber, a polypropylene compound-containing resin and a polyethylene 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, since the thickness of the fiber of the polypropylene compound component, which is a part of the side-by-side composite fiber, becomes thicker, the porosity of the fiber aggregate decreases and the amount of air contained is relatively reduced, so the flow of sound energy by the ultrafine fibers and the air layer 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 in that the bondability with the fibers of the polyethylene-based compound component constituting the component is poor, the structure of the composite fiber aggregate may be deteriorated, so it is preferable to perform it within the temperature range.

The melt blown composite fiber is a side-by-side type composite fiber, and may include 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 of increasing fineness due to radioactive degradation and increasing overall defects in the fiber aggregate.

)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 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 is 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

), 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, so it is better to use a material having an MI within the range.

)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 adhesive force of the side-by-side composite fiber with 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 in that the flowability is lowered and the fineness of the melt blown fiber is thickened, and the MI is 160 g/10 min (190

) is used, the melt-blown fiber breakage phenomenon 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.

In addition, the coating layer may be made of aramid fibers having an areal density of 140 to 160 g / m2.

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, and AgDF (metal). , Al, Cu, Ti, Zn, Fe, Mn, Cr, and the like.

When the incident sound reaches 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 absorbing 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 the process of absorbing the low sound, by adjusting the natural frequency of the pattern by changing the material, size and shape of the pattern composed of polymer, piezoelectric material, and metal, etc. as described above, as well as diffuse reflection, it is possible to absorb low sound or frequencies in a specific sound range. may be configured.

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.

6 is a view for explaining a PRA structure in which a resonant frequency is improved by using a rib structure according to one disclosure.

According to one disclosure, the noise reduction unit is a grid-type structure 133 mounted to protrude from the outer surface of at least a portion of the PRA 120 in order to reinforce the structural rigidity of the PRA 120 .

The grid-like structure 133 serves to change the rigidity of the PRA 120 made of a plastic material.

According to one disclosure, the grid-type structure 133 may be mounted by digging a groove on the outside of the PRA 120 , and may be mounted on a part or all of the outer surface of the PRA 120 .

The lattice structure 133 according to one disclosure is 6.0 to 8.0 wt% Cr, 3.8 to 5.0 wt% Mo, 0.015 to 0.035 wt% C, 0.2 to 0.5 wt% Si, 1.8 to 2.6 wt% Mn , 0.01 to 0.018 wt% P, 0.005 to 0.01 wt% or less S, 0.15 to 0.4 wt% Sn, 0.015 to 0.055 wt% RE, 0.10 to 0.18 wt% V, 0.01 to 0.030 wt% Ti and It may be a steel structure composed of 85.5 to 87.8 wt% Fe.

When the grid structure 133 is a steel structure, the elongation is 7.6% or more, the yield strength (YS) is 730 MPa or more, the tensile strength (TS) is 850 MPa or more, and the ratio of tensile strength to yield strength (TS/YS) It is characterized in that 1.15 or more.

에서 재가열하는 단계, (b) 재가열된 강재를 920 ~ 1000

의 최종 마무리 압연 온도 조건으로 열간 압연하는 단계, 및 (c) 열간 압연된 강재에 대하여 템프코어 공정을 수행하는 단계로 제조될 수 있다.According to one disclosure, the lattice structure 133 is (a) carbon (C): 0.10 to 0.40 wt%, manganese (Mn): 1.0 to 1.5 wt%, silicon (Si): 0.05 to 0.50 wt%, chromium (Cr) ): 0.10 to 1.00 wt%, Vanadium (V): 0.08 to 0.18 wt%, Copper (Cu): More than 0 and 0.40 wt% or less, Molybdenum (Mo): More than 0 and 0.50 wt% or less, Aluminum (Al): 0.005 to 0.070% by weight, nickel (Ni): more than 0, 0.25% by weight or less, phosphorus (P): more than 0, 0.05% by weight, sulfur (S): more than 0, 0.030% by weight or less, nitrogen (N): 0.005 to 0.025 1050 ~ 1100 of steel consisting of weight % and remaining iron (Fe) and other unavoidable impurities

Step of reheating in, (b) 920 ~ 1000 of the reheated steel

Hot rolling under the final finishing rolling temperature condition of, and (c) performing a temp core process on the hot-rolled steel.

In the method of manufacturing rebar according to an embodiment, after LF, which is the secondary refining process, after LF, the oxygen content was lowered and the reinforcing bar was solidified into a semi-material in the casting process to improve fatigue resistance.

까지 재가열 한다. 다음으로, 열간 압연 공정은 각 압연롤(RM, IM, FM)을 거치며 최종 마무리압연을 920 ~ 1000

에서 변형이 완료 후, 템프코어(Tempcore)를 거치며 표면은 마텐사이트 시작온도(Ms)까지 급랭 후, 500 ~ 700

까지 복열단계를 포함하는 것을 특징으로 한다.The rolling process is manufactured through a reheating process, a hot deformation process, and a cooling process. In the reheating process, the semi-finished billets are 1050 to 1100

reheat until Next, in the hot rolling process, each rolling roll (RM, IM, FM) goes through the final finishing rolling of 920 ~ 1000

After transformation is completed in

It is characterized in that it includes a recuperation step.

Steel is carbon (C): 0.10 to 0.40 wt%, manganese (Mn): 1.00 to 1.5 wt%, silicon (Si): 0.05 to 0.50 wt%, chromium (Cr): 0.10 to 1.00 wt%, vanadium (V) : 0.08 to 0.18% by weight, copper (Cu): more than 0 and 0.40% by weight or less, molybdenum (Mo): more than 0 to 0.50% by weight or less, aluminum (Al): 0.005 to 0.070%, nickel (Ni): more than 0 0.25 wt% or less, phosphorus (P): more than 0 and 0.05 wt% or less, sulfur (S): more than 0 and 0.030 wt% or less, nitrogen (N): 0.005 to 0.025% and the remaining iron (Fe) and other unavoidable impurities. can

The grid-type structure 133 according to one disclosure may be made of a metamaterial. Here, the metamaterial refers to a material that exhibits physical properties that do not exist in nature, and a material that can reduce vibration or vibration noise in a frequency band in which effective mass or effective stiffness has a negative value to be. In general, metamaterials repeatedly arrange one small structure to implement negative properties in a specific frequency band, and such a structure is called a phononic crystal.

Acoustic crystal is a structure in which units having a length less than half the length of the wavelength of sound waves are periodically arranged. A periodic artificial structure called acoustic crystal can block sound or vibration energy in a specific frequency band without reflecting or transmitting it, and when a specific area is covered with this acoustic metamaterial, it is completely hidden and isolated from external wave energy There are advantages to doing it.

And the unit cell refers to one of the structures in which the same structure is repeatedly arranged in the acoustic crystal. A representative method for realizing effective negative mass is to use a local resonant structure.

The method according to an embodiment of the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software. Examples of the computer-readable recording medium include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floppy disks. - includes magneto-optical media, and hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto. belong to the scope of the right.

Claims (7)

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
and a noise reduction unit 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 in the PRA. The method of claim 1,
The noise reduction unit,
An apparatus for reducing noise caused by driving a brake, characterized in that by adding a mass in a predetermined range to the PRA, a natural vibration frequency generated when the PRA is driven is changed. The method of claim 1,
The noise reduction unit,
A sound absorbing material mounted on the outer surface of at least a portion of the PRA,
The sound absorbing material,
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 comprising 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 noise caused by brake driving, characterized in that it comprises a coating layer coated with a thermosetting adhesive 38 to 45 g/m ^{2 on the upper surface of the pattern layer.} The method of claim 1,
The noise reduction unit,
A lattice-type structure mounted to protrude from the outer surface of at least a part of the PRA in order to reinforce the structural rigidity of the PRA,
The lattice structure comprises 6.0 to 8.0 wt% Cr, 3.8 to 5.0 wt% Mo, 0.015 to 0.035 wt% C, 0.2 to 0.5 wt% Si, 1.8 to 2.6 wt% Mn, 0.01 to 0.018 wt% of P, 0.005 to 0.01 wt% or less S, 0.15 to 0.4 wt% Sn, 0.015 to 0.055 wt% RE, 0.10 to 0.18 wt% V, 0.01 to 0.030 wt% Ti and 85.5 to 87.8 wt% Fe As a steel structure consisting of
The steel structure has an elongation of 7.6% or more, a yield strength (YS) of 730 MPa or more, a tensile strength (TS) of 850 MPa or more, and a ratio of tensile strength to yield strength (TS/YS) of 1.15 or more , A device that reduces noise caused by brake driving. The method of claim 1,
determining the frequency range of the piezoelectric noise generated as the vehicle travels, determining the frequency range of a range that does not match the natural vibration frequency range of the piezoelectric noise, and moving the natural vibration frequency of the PRA to the frequency range A device for reducing noise according to driving a brake, comprising: a noise control unit configured to determine a property of the noise reduction unit for the purpose; and a noise control unit configured to transmit the determined property of the noise reduction unit to a user terminal. 6. The method of claim 5,
The noise control unit,
Obtaining driving information of the vehicle and surrounding state information of the vehicle,
Based on the obtained information, determining the type of noise reduction unit for changing the natural vibration frequency of the PRA,
Determining the properties of the noise reduction unit including at least one of the determined component, weight and material of the noise reduction unit,
An apparatus for reducing noise caused by driving a brake, which predicts the natural vibration frequency of the PRA according to the determined property of the noise reduction unit and determines whether it matches the frequency of the piezoelectric noise. The method of claim 1,
and a vehicle control unit that controls the driving of the vehicle and determines whether the PRA operates normally by using the magnitude of the piezoelectric noise generated as the vehicle travels,
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 the plurality of relays, and when the PRA is in the normal operating range, Changing the properties of the noise reduction unit capable of reducing the size, outputting a warning message to stop the driving of the vehicle when the PRA is out of the normal operating range, and generating diagnostic information on the failure state of the PRA A device for reducing noise caused by driving a brake, characterized in that.

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