KR20200048877A - Refrigerator - Google Patents

Abstract

The purpose of the present invention is to provide a freezer capable of tuning compressor driving noise during a trial operation. To this end, the freezer of the present invention may include: an outer case installed in a compressor or arranged inside a discharge body between the compressor and a condenser; a stationary porous pipe fixed inside the outer case and having a plurality of first holes; a mobile porous pipe arranged to linearly move along the stationary porous pipe and having a plurality of second holes; and a regulator connected to the moving porous pipe and moving the mobile porous pipe to regulate the cross-sectional area of a region wherein the first holes and the second holes communicate in a radial direction.

Description

Refrigerator {Refrigerator}

The present invention relates to a freezer.

A refrigerator is a machine that cools or freezes a liquid by obtaining a low temperature by a refrigerant, and the main part of the refrigerator is composed of four parts: a compressor, a condenser, an expansion mechanism, and an evaporator. Depending on the method of transporting the refrigerant, there are a compression type (reciprocating, rotary, centrifugal freezer) and absorption type.

A compressor is a device for compressing a fluid such as refrigerant gas, and may be classified into a centrifugal compressor, a rotary compressor, a reciprocating compressor, a scroll compressor, etc. according to a method of compressing the fluid. By compressing the fluid while inhaling in the axial direction and discharging in the centrifugal direction, it may include an impeller and a motor that rotates the impeller. In addition, the centrifugal compressor may further include an inverter that changes the speed of the motor.

The compressor may be connected to the evaporator and the suction body, may be connected to the condenser and the discharge body, and may compress the refrigerant evaporated from the evaporator and then discharge it to the compressor.

On the other hand, when a sound absorber or a noise reduction device is mounted on the inside and the discharge body of the compressor, the compressor can reduce noise, and an example of a refrigerator equipped with a noise reduction device on the inside and the discharge body of the compressor is a Korean registered patent. It is disclosed in Publication 10-0514655 (announced on September 14, 2005).

The noise reduction device disclosed in Korean Patent Registration No. 10-0514655 (announced on September 14, 2005) includes a cylindrical appearance, a porous tube interposed inside the exterior, and a retaining ring to prevent separation of the porous tube do.

However, the noise reduction device disclosed in Republic of Korea Patent Publication No. 10-0514655 (published on September 14, 2005) is designed to have a large attenuation effect on a specific frequency, there is a problem that it is not easy to modify after installation.

Republic of Korea Registered Patent Publication No. 10-0514655 (announced on September 14, 2005)

An object of the present invention is to provide a refrigerator capable of tuning noise according to compressor operation during commissioning.

Another object of the present invention is to provide a refrigerator that can actively respond to noise changes by varying the hole cross-sectional area of the perforated tube when the noise changes according to the change in the rotational speed of the compressor.

A refrigerator according to an embodiment of the present invention includes an outer cylinder installed in a compressor or disposed inside the discharge body between the compressor and the condenser, and a fixed porous tube fixed in the outer cylinder and having a plurality of first holes formed therein; A movable porous tube arranged to move linearly along the fixed porous tube and having a plurality of second holes formed therein; It may be connected to the movable porous tube and move the movable porous tube to include an adjuster for adjusting the cross-sectional area of the region through which the first hole and the second hole pass in the radial direction.

 The outer diameter of the movable perforated tube may be larger than the outer diameter of the fixed perforated tube and may be smaller than the inner diameter of the outer cylinder.

The length of the movable porous tube may be shorter than the length of the fixed porous tube.

The adjuster may include an adjustment shaft, a pinion connected to the adjustment shaft, and a rack provided in the movable perforated tube and engaged with the pinion.

An adjustment shaft through-hole through which an adjustment shaft passes may be formed in the outer cylinder.

An adjustment shaft accommodating portion in which an adjustment shaft is accommodated may be formed between the movable porous tube and the outer cylinder.

The compressor may further include a volute that guides the refrigerant to the discharge body.

A control shaft through-hole through which the control shaft passes may be formed in the volute or discharge body.

The refrigerator may further include a motor connected to the control shaft.

The refrigerator may further include a microphone that measures noise of at least one of the compressor and the discharge body, and a controller that controls the motor according to the noise measured by the microphone.

According to an embodiment of the present invention, it is possible to adjust the regulator while commissioning after installing the refrigerator so that the noise of the refrigerator is minimized.

In addition, by adjusting the cross-sectional area of the region where the first hole of the fixed porous tube communicates with the second hole of the moving porous tube, noise can be adjusted when a specific frequency is changed after the compressor is mounted.

In addition, the movable perforated tube and the outer cylinder can protect the control shaft.

In addition, since the motor is disposed outside the outer cylinder, space utilization inside the outer cylinder is high, and the motor is minimized from being damaged by high temperature refrigerant.

In addition, when the rotational speed of the compressor is variable, the moving perforated tube may be moved more actively to the noise change as the moving perforated pipe moves with respect to the noise variable according to the compressor rotational speed.

In addition, the movable porous tube is located between the fixed porous tube and the outer tube, and the fixed porous tube and the outer tube can protect the movable porous tube.

In addition, there is an advantage in that the flow path resistance is less than when the movable porous pipe is located outside the fixed porous pipe and the movable porous pipe is located inside the fixed porous pipe.

1 is a diagram showing a refrigerator according to an embodiment of the present invention,
2 is a perspective view of a refrigerator according to an embodiment of the present invention,
3 is a view showing a volume and noise reduction device of a refrigerator according to an embodiment of the present invention,
Figure 4 is a cross-sectional view when the hole of the noise reduction device shown in Figure 3 is the maximum open,
5 is a side view of the fixed porous tube and the movable porous tube shown in FIG. 4,
Figure 6 is a cross-sectional view when the open area of the hole of the noise reduction device shown in Figure 4 is reduced than in the case of Figure 4,
7 is a side view of the fixed porous tube and the movable porous tube shown in FIG. 6,
8 is a control block diagram of a refrigerator according to an embodiment of the present invention.

Hereinafter, a specific embodiment of the present invention will be described in detail with the accompanying drawings.

1 is a view showing a freezer according to an embodiment of the present invention, and FIG. 2 is a perspective view of a freezer according to an embodiment of the present invention.

The refrigerator of the present embodiment may include a compressor 1 through which refrigerant is circulated, a condenser 2, an expansion mechanism 3 and an evaporator 4.

The compressor 1 can compress the refrigerant evaporated in the evaporator 4. The refrigerant discharged from the compressor 1 after being compressed by the compressor 1 may be sucked into the compressor 1 after sequentially passing through the condenser 2, the expansion mechanism 3 and the evaporator 4.

The compressor 1 can compress the gas refrigerant introduced from the evaporator 4. The compressor 1 may be configured to have a variable operating capacity, and may be configured to compress refrigerant in multiple stages.

The compressor 1 may include a motor 10 that generates a driving force for compressing the refrigerant. The motor 10 may be an AC motor or a three-phase induction motor. The motor 10 may include a motor housing 12 having a space formed therein.

The motor 10 may further include a shaft, a rotor mounted on the outer circumference of the shaft, and a stator installed inside the motor housing 12 to surround the outer circumference of the rotor. The rotor may include a magnet, and the stator may include a stator core and a coil wound around the stator core.

The compressor 1 may be connected to the evaporator 4 and the suction body 5, and may be connected to the condenser 2 and the discharge body 6.

The compressor 1 may be a centrifugal compressor that sucks refrigerant gas in an axial direction and discharges it in a centrifugal direction.

When the compressor 1 is a centrifugal compressor, the compressor 1 may further include a volute case 20.

When the compressor 1 is a centrifugal compressor, the compressor 1 may include a centrifugal impeller connected to the shaft of the motor 10.

The centrifugal impeller may be rotatably accommodated in the impeller receiving space formed inside the volute case 20, and compress the gas refrigerant to flow toward the volute 22.

The compressor 1 may further include an inlet guide 21. The inlet guide 21 is connected to the volute case 20 to guide the gas refrigerant to the volute case 20.

The suction body 5 may be connected to the inlet guide 21, and the refrigerant flowing from the suction body 5 may be guided into the ball tuft case 20.

The volute 22 may be connected to the discharge body 6, and the volute 22 may be guided to the discharge body 6 by the refrigerant discharged after being compressed by the compressor 1.

The discharge body 6 guides the refrigerant discharged from the compressor 1 to the condenser 2, and may be integrally formed with the volute 22 of the compressor 1, and integrally with the condenser 2 It is also possible to form.

Each of the condenser 2 and the evaporator 3 may be a shell and tube heat exchanger, and in this case, each of the condenser 2 and the evaporator 3 is disposed in a shell having a substantially cylindrical shape and inside the shell. It may include an inner tube through which cooling water or cold water passes.

Cooling water is introduced and discharged into the condenser 2, and heat exchange between the refrigerant and the coolant may be performed inside the condenser 2. And the cooling water can be heated in the process of passing through the condenser 2.

The expansion mechanism 3 may be an electromagnetic expansion valve disposed between the condenser 3 and the evaporator 4.

Cold water is introduced and discharged into the evaporator 4, and heat exchange between the refrigerant and the cold water may be performed inside the evaporator 4. The cold water is cooled in the process of passing through the evaporator 4, and the cooled cold water is supplied to the cold water demand source.

The compressor 1 may be installed to be located above the condenser 2 or the evaporator 4, and may be modularized with the condenser 2 and the evaporator 4.

The refrigerator may include a compressor 1, particularly an inverter 7 (see FIG. 2) that changes the rotational speed of the motor 10 by changing the frequency of the motor 10.

The inverter 7 may include an inverter enclosure 90 (see FIG. 2). A space in which various control parts capable of controlling the compressor 1, especially the motor 10 may be formed may be formed inside the inverter enclosure 90.

The inverter 7 may further include a door 91 (see FIG. 2) connected to the inverter enclosure to open and close the space.

Meanwhile, the refrigerator may further include a noise reduction device 30 for reducing noise generated by the compressor 1.

The noise reduction device 30 may be mounted on at least one of the compressor 1 and the discharge body 6 in order to efficiently reduce noise generated and propagated by the compressor 1. When the noise reduction device 30 is mounted on the compressor 1, the noise reduction device 30 may be mounted on the ball tuft 22.

3 is a view showing a volute and a noise reduction device of a refrigerator according to an embodiment of the present invention, FIG. 4 is a cross-sectional view when the hole of the noise reduction device shown in FIG. 3 is fully opened, and FIG. 5 is a view 4 is a side view of the fixed porous tube and the movable porous tube, and FIG. 6 is a cross-sectional view when the opening area of the hole of the noise reduction device shown in FIG. 4 is reduced than in the case of FIG. 4, and FIG. 7 is shown in FIG. 6 It is a side view of the fixed perforated tube and the movable perforated tube, Figure 8 is a control block diagram of a refrigerator according to an embodiment of the present invention.

The refrigerator may include an outer cylinder 40, a fixed perforated pipe 50, a movable perforated pipe 60, and a regulator 70, and the outer cylinder 40, a fixed perforated pipe 50, and a movable c Synopsis 60 and the regulator 70 may constitute a noise reduction device 30.

The noise reduction device 30 may be mounted inside the volute 22 or inside the discharge body 6, in this case, inside the volute 22 or inside the discharge body 6, the noise reduction device A receiving portion 24 for accommodating at least a portion of the 30 may be formed. An example of the receiving portion 24 may be a groove portion formed in a recessed shape on the inner circumferential surface of the volute 22 or the inner circumferential surface of the discharge body 6.

The outer cylinder 40 and the fixed perforated pipe 50 and the movable perforated pipe 60 constitute a Helmholtz resonator, but the size of the hole cross-sectional area of the fixed perforated pipe 50 and the movable perforated pipe 60 is adjusted ( 70).

The outer cylinder 40 may be installed in the compressor 1 or disposed inside the discharge body 6 between the compressor 1 and the condenser 2. The outer cylinder 40 may be mounted inside the ball tuft 22 or the discharge body 6. The outer cylinder 40 may be inserted into the receiving portion 24 formed on the inner circumferential surface of the volute 22 or the discharge body 6 and mounted.

The outer diameter D6 of the outer cylinder 40 may be the same as the inner diameter of the receiving portion 24, and the outer cylinder 40 may be mounted by being pressed into the volute 22 or the discharge body 6.

A space in which the fixed porous tube 50 and the movable porous tube 60 can be disposed may be formed inside the outer cylinder 40.

The inner diameter D5 of the outer cylinder 40 may be larger than the outer diameter D2 of the fixed perforated pipe 50, and the inner diameter D5 of the outer cylinder 40 may be larger than the outer diameter D4 of the movable perforated pipe 60. have.

The fixed perforated pipe 50 may be combined with the outer cylinder 40 by at least one fixed ring, and the fixed perforated pipe 50 may be spaced apart from the outer cylinder 40 by a fixed ring.

A fixed ring may be provided in a pair of refrigerators, noise may be absorbed between the pair of fixed rings 56, 58 and the fixed perforated plate 50 and the outer cylinder 40, and the moving porous tube 60 ) May be formed a space that can be moved linearly.

Noise reduction device 30 of the present embodiment may be a variable Helmholtz resonator (Hlmholtz resonator), the resonance frequency can be variable, the volume of the space formed inside the outer tube 40, the fixed perforated tube 50 and The resonance frequency can be varied by the cross-sectional area of the hole formed by the moving porous tube 60.

The fixed perforated tube 50 and the movable perforated tube 60 may constitute a neck portion (neck) of the Helmholtz resonator, and the shape and shape of the neck portion (neck) according to the position of the moving perforated tube 60 The hole cross-sectional area can be varied. The noise reduction device 30 of this embodiment may constitute a Helmholtz resonator with a variable resonance frequency.

The fixed porous tube 50 is fixed inside the outer cylinder 40 and a plurality of first holes 52 may be formed.

A passage P through which the refrigerant passes may be formed inside the fixed porous tube 50, and the plurality of first holes 52 may be opened in the radial direction R. The plurality of first holes 52 may be formed in a circular shape or an oval shape. The plurality of first holes 72 may be partially blocked by the moving porous tube 60, in which case, the cross-sectional area of the open area without being blocked by the moving porous tube 60 among the plurality of first holes 72 It can be the cross-sectional area of the neck of this Helmholtz resonator.

Each of the plurality of first holes 52 may have a different degree of opening depending on the positions P1 and P2 of the moving porous tube 60. The larger the area of the first hole 52 that is shielded by the moving porous tube 60, the smaller the cross-sectional area of the neck of the Helmholtz resonator. Conversely, the smaller the area of the entire cross-sectional area of the first hole 52 that is blocked by the moving porous tube 60, the larger the cross-sectional area of the neck of the Helmholtz resonator.

4 is a case where the mobile porous tube 60 does not shield the first hole 52, in this case, the resonance frequency of the Helmholtz resonator may be determined by the total cross-sectional area of the first hole 52.

As shown in FIG. 4, when the second hole 62 coincides with the first hole 52 in the radial direction R as much as possible, the cross-sectional area of the opened area of the first hole 52 is shown in FIG. 5 As can be, it can be maximized.

Conversely, as shown in FIGS. 6 and 7, when a portion of the second hole 62 faces the periphery 52a of the first hole 52 in the radial direction R, a portion of the first hole 52 The region H1 may be blocked by the moving porous tube 60.

When the cross-sectional area of the open area H2 without being blocked by the moving porous tube 60 among the first holes 52 is as shown in FIG. 6, when the cross-sectional area of the open area among the first holes 52 is maximum ( 4).

The movable porous tube 60 may be arranged to move linearly along the fixed porous tube 50. A plurality of second holes 62 may be formed in the movable porous tube 60.

The movable porous tube 60 may be movably disposed outside the fixed porous tube 60, and the diameter of the movable porous tube 60 may be larger than the diameter of the fixed porous tube 60. The diameter of the movable porous tube 60 may be smaller than the diameter of the outer cylinder 40.

The movable porous tube 60 may also be arranged to be movable linearly inside the fixed porous tube 50.

In this case, an example for connecting the moving porous tube 60 and the regulator 70 is an adjusting shaft through-hole through which the adjusting shaft 72 of the regulator 70 is linearly movable through the fixed porous pipe 50. Can be formed.

As another example for connecting the movable porous tube 60 and the regulator 70, the regulator 70 may be disposed in the longitudinal direction of the movable porous tube 60.

Hereinafter, an example in which the movable porous tube 60 is linearly moved along the fixed porous tube 50 from the outside of the fixed porous tube 50 will be described.

However, it is needless to say that the present invention is not limited to that the movable porous tube 60 is located outside the fixed porous tube 50.

The movable porous tube 60 may slide along the fixed porous tube 50 in a space formed between the fixed porous tube 50 and the outer cylinder 40.

To this end, the outer diameter D4 of the movable porous tube 60 may be larger than the outer diameter D2 of the fixed porous tube 50 and smaller than the inner diameter D5 of the outer cylinder 40. The inner diameter D3 of the movable porous tube 60 may be formed slightly larger than the outer diameter D2 of the fixed porous tube 50 or the same.

The inner diameter D3 of the movable porous tube 60 may have a size such that the movable porous tube 60 can slide while being guided to the outer circumferential surface of the fixed porous tube 60.

The length L1 of the movable porous tube 60 may be shorter than the length L2 of the fixed porous tube 50. The length (L1) of the movable perforated tube 60 may be shorter than the distance that the pair of fixed rings 56 and 58 are spaced apart, and the movable porous tube 60 may have a pair of fixed rings 56 and 58 It can be moved in a straight line in the longitudinal direction (L) of the moving perforated pipe (60).

The movable porous tube 60 can be moved in a space formed between the outer cylinder 40 and the fixed porous tube 50 and a pair of fixed rings 56 and 58, and the length of the moving porous tube 60 (L1) ) Is shorter than the length (L2) of the fixed perforated pipe 50, the movement of the moving perforated pipe 60 may be possible.

The movable porous tube 60 may move at least a portion of the first hole 52 while being moved outside the fixed porous tube 50.

The opening degree of each of the plurality of second holes 62 may be determined according to the positions P1 and P2 of the movable porous tube 60.

As shown in FIG. 4, when the second hole 62 coincides with the first hole 52 in the radial direction R as much as possible, the cross-sectional area of the opened area of the second hole 52 is shown in FIG. 5 As can be, it can be maximized.

Conversely, as shown in FIGS. 6 and 7, when a part of the second hole 62 faces the periphery 52a of the first hole 52 in the radial direction R, the second hole 62 Some areas H3 may be blocked by the fixed porous tube 50.

When the cross-sectional area of the open area H4 is not blocked by the fixed perforated tube 50 of the second hole 62, as shown in FIG. 6, when the cross-sectional area of the open area of the second hole 62 is the maximum (See FIG. 4).

In this embodiment, the cross-sectional area of the region through which the first hole 52 and the second hole 62 pass in the radial direction R may be a cross-sectional area of the neck of the Helm Resonator. The larger the area where the movable porous tube 60 shields the first hole 52, the smaller the cross-sectional area of the neck of the Helmholtz resonator, and the smaller the area where the movable porous tube 60 shields the first hole 52, the smaller the Helmholtz area. The cross section of the neck of the resonator becomes large.

In the present embodiment, noise of various frequencies can be reduced by changing the hole cross-sectional area.

The adjuster 70 may adjust the cross-sectional area of the region through which the first hole 52 and the second hole 62 pass in the radial direction R.

The regulator 70 may be connected to the moving porous tube 60 to move the moving porous tube 60. The regulator 70 may be a moving mechanism for linearly moving the moving porous tube 60.

The adjuster 70 may include an adjustment shaft 72, a pinion 74 connected to the adjustment shaft 72, and a rack 76 provided to the moving perforated tube 60 and the pinion 74 engaged. .

The adjustment shaft 72 may be arranged to be long in a direction orthogonal to the moving direction of the moving porous tube 60.

A portion of the adjustment shaft 72 may protrude outside the outer cylinder 40. In this case, an adjustment shaft through hole 44 through which the adjustment shaft 72 passes may be formed in the outer cylinder 40.

Between the movable porous tube 60 and the outer cylinder 40, an adjustment shaft accommodating space S in which an adjustment shaft 72 is accommodated may be formed.

A portion of the adjustment shaft 72 may protrude out of the ball tuft 22, in this case, the adjustment shaft through hole 26 through which the adjustment shaft 72 passes may be formed in the volute 22.

The adjuster 70 may be configured to allow the operator to manually operate the adjustment shaft 72, or may be configured to operate the adjustment shaft 72 by a driving source such as a motor 80.

A part of the adjustment shaft 72 may be exposed to the outside of the volute 22, in this case, the operator rotates the portion located outside the ball tuft 22 of the adjustment shaft 72 to move the porous tube 60 It is also possible to move.

In this case, it is preferable that a handle that the operator can hold by hand is provided on a portion of the adjustment shaft 72 that is located outside the volute 22. In this case, the adjuster 70 may be a manual adjuster for manually manipulating the position of the moving porous tube 60.

At the time of commissioning of the refrigerator, an operator can check the noise change while rotating the control shaft 72 or the handle little by little according to the noise measured by a noise meter such as a microphone, and can adjust the control shaft 72 to minimize noise.

The pinion 74 may be connected to a portion accommodated in the adjustment shaft accommodating space S of the adjustment shaft 72.

The rack 76 is a configuration capable of determining the maximum moving distance of the moving porous tube 60, and it is possible to be integrally formed with the moving porous tube 60, and is manufactured separately from the moving porous tube 60 and then moved. Of course, it is also possible to be coupled to the synoptic (60).

The rack 76 may be disposed in the movable porous tube 60 in the longitudinal direction of the movable porous tube 60.

Meanwhile, the refrigerator may further include a motor 80 connected to the control shaft 72. The motor 80 may rotate the adjustment shaft 72 outside the outer cylinder 40, and the motor 80 may be mounted on the outer surface of the volute 22.

On the other hand, the freezer comprises a microphone 90 for measuring noise of at least one of the compressor 1 and the discharge body 60, and a controller 100 for controlling the motor 80 according to the noise measured by the microphone 90. It may further include.

The controller 100 can control the motor 80 so that the noise measured by the microphone 90 is reduced, and even if the noise generated by the compressor 1 is variable, the motor 80 adjusts the shaft in response to this noise change. (72) can be rotated.

In this embodiment, all of the first hole 52 is not shielded by the moving porous tube 60, and a part of the first hole 52 may be shielded by the moving porous tube 60, and the controller 100 The first hole 52 may control the motor 80 so that all is not shielded.

The present invention is not limited to the adjustment shaft 72, the pinion 74, the rack 76, and the motor 80, as long as the configuration of the movable perforated tube 60 can be linearly moved, the perforated moving tube ( It is of course possible to include a linear motor connected to 60) or a hydraulic cylinder or a pneumatic cylinder.

The above description is merely illustrative of the technical idea of the present invention, and those of ordinary skill in the art to which the present invention pertains may make various modifications and variations without departing from the essential characteristics of the present invention.

Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments.

The scope of protection of the present invention should be interpreted by the claims below, and all technical spirits within the equivalent range should be interpreted as being included in the scope of the present invention.

1: Compressor 2: Condenser
6: discharge body 40: outer cylinder
50: fixed perforated plate 52: first hole
60: mobile multi-purpose tube 62: second hole
70: adjuster 72: adjust shaft
74: pinion 76: rack
80: motor

Claims (9)

An outer cylinder disposed in the compressor or disposed inside the discharge body for guiding the refrigerant discharged from the compressor to the condenser;
A fixed porous tube fixed in the outer cylinder and having a plurality of first holes formed therein;
A movable porous tube arranged to move linearly along the fixed porous tube and having a plurality of second holes formed therein;
A refrigerator connected to the movable porous tube and including a regulator for moving the movable porous tube to adjust a cross-sectional area of a region through which the first hole and the second hole pass in the radial direction. According to claim 1,
The outer diameter of the movable perforated tube is larger than the outer diameter of the fixed perforated tube, and smaller than the inner diameter of the outer cylinder. According to claim 1,
The length of the movable porous tube is shorter than the length of the fixed porous tube. According to claim 1,
The regulator is an adjustment shaft,
A pinion connected to the adjustment shaft,
A refrigerator provided in the mobile perforated tube and including a rack in which the pinion is meshed. The method of claim 4,
The outer cylinder is a refrigerator having a control shaft through hole through which the control shaft passes. The method of claim 4,
A refrigerator having an adjustment shaft accommodating space in which the adjustment shaft is accommodated between the movable porous tube and the outer cylinder. The method of claim 4,
In the volute or discharge body, a freezer having a control shaft through hole through which the control shaft passes. The method of claim 4,
The refrigerator further comprising a motor connected to the control shaft. The method of claim 8,
A microphone measuring noise of at least one of the compressor and the discharge duct;
The refrigerator further comprising a controller that controls the motor according to the noise measured by the microphone.

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