Silencers and motor equipment, fan motor units, washing machines, and electrical equipment that incorporate them.

Abstract

We provide a silencer that reduces noise from a sound source, and motor equipment, fan motor units, washing machines, and electrical equipment that incorporate it. [Solution] The silencer 201 of the present invention has a chamber 202 formed around a sound source 101, which defines a space, and a wall body 203 that forms the chamber 202 and is provided with slits 204. Multiple slits 204 are configured in the circumferential direction of the sound source 101, with the slits 204 facing the sound source 101, and the wall body 203 is made of a thin plate or membrane.

Description

Technical Field

[0001] The present invention relates to a muffler, a motor device equipped with the same, a fan motor unit, a washing machine, and an electric device.

Background Art

[0002] As a means for reducing noise generated from a mechanical device or the like, mufflers are widely used. A muffler is a device that reduces the propagation of noise by utilizing sound absorption, reflection, interference, etc. Mufflers are classified into several types based on the noise reduction principle. For example, expansion type, interference type, resonance type, etc. are well known. Mufflers are also used in household appliances, and various inventions have been made. In particular, as technologies related to mufflers for household appliances equipped with a motor, the following inventions are disclosed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1 and Patent Document 2, by attaching a muffler to a blower motor, it is intended to reduce the noise generated from the blower motor. However, in Patent Documents 1 and 2, since a resonance type muffler is used, a noise reduction effect is expected only for a specific single frequency. Therefore, in order to cope with fluctuating sounds such as a blower motor, that is, multiple frequencies, multiple mufflers are required. Therefore, there is a problem that the size of the entire muffler having multiple mufflers becomes relatively large compared to other mufflers such as the interference type.

[0005] The present invention was made to solve the above problems and aims to provide a silencer that appropriately reduces noise from a sound source, and a motor device, fan motor unit, washing machine, and electrical equipment equipped with the silencer. [Means for solving the problem]

[0006] To solve the aforementioned problems, the silencer of the present invention comprises a chamber formed around a sound source, defining a space, and a wall body forming the chamber and having slits, wherein a plurality of slits are configured in the circumferential direction of the sound source, facing the sound source, and the wall body is made of a thin plate or membrane. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a silencer that appropriately reduces noise from a sound source, and motor equipment, fan motor units, washing machines, and electrical equipment equipped with the silencer. [Brief explanation of the drawing]

[0008] [Figure 1] This is a side cross-sectional view of the silencer according to the first embodiment of the present invention, as seen from the side when attached to a motor. [Figure 2] This is a cross-sectional view II in Figure 1. [Figure 3] This is a cross-sectional view of a motor and a silencer, taken at a cross-section perpendicular to the rotation axis of the motor, when the motor is attached to the silencer according to a second embodiment of the present invention. [Figure 4] This is a side cross-sectional view of the silencer according to the third embodiment of the present invention, as seen from the side when attached to a motor. [Figure 5] This is an external perspective view of a drum-type washing machine and dryer equipped with a silencer according to the first embodiment of the present invention. [Figure 6] This is a longitudinal cross-sectional view of a drum-type washing machine and dryer equipped with a silencer according to the first embodiment of the present invention. [Figure 7] This is an enlarged cross-sectional view of a blower unit equipped with a silencer according to the first embodiment of the present invention. [Modes for carrying out the invention]

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. <<First Embodiment>> Figure 1 is a side cross-sectional view of the silencer 201 according to the first embodiment of the present invention, as seen from the side when attached to the motor 101.

[0010] Figure 2 is a cross-sectional view of section II in Figure 1. The silencer 201 according to the first embodiment is mounted around the motor 101, which is roughly cylindrical in shape. A fan or blower, which acts as a motor load, can be attached to the shaft 102, which is the rotating axis of the motor 101, as needed. The silencer 201 has an annular cylindrical shape around the motor 101. In other words, the silencer 201 is formed in a cylindrical shape around the motor 101. Inside the silencer 201, there is an annular cavity 201k chamber 202 (see Figure 2). By forming the silencer 201 in a cylindrical shape around the motor 101, noise from the motor (sound source) 101 can be effectively suppressed.

[0011] The chamber 202 is defined by a thin plate 203 and a thick plate 203t of the inner perimeter panel. The thick plate 203t has an outer perimeter plate, a top plate (see Figure 1), a bottom plate (see Figure 1), and radial plates spaced approximately 90 degrees apart (see Figure 2). The inner circumferential plate (wall) on the motor 101 side of chamber 202 is formed of a thin plate 203. The thin plate 203 may also be a film. A slit 204, which is a hole, is formed in the thin plate 203. The shape of the slit 204 is arbitrary and not limited to a round hole, elongated hole, square hole, etc.

[0012] The thin plate 203 is formed of, for example, a sheet or film of PET (Polyethyleneterephthalate). The thick plate 203t is formed of, for example, an acrylic transparent resin, a high-hardness silicone rubber, etc. Note that the material of the thin plate 203 and the material of the thick plate 203t may be appropriately selected as long as a predetermined sound absorption effect (sound insulation effect) is achieved. The thin plate 203 shown in FIG. 2 is joined to the thick plate 203t using an adhesive or the like.

[0013] In FIG. 1, the case where the chamber 202 is in one stage in the vertical direction (the direction along the shaft 102) is illustrated, but there is no restriction on the number of stages. For example, the number of stages may be changed to a plurality of stages depending on the size of the motor 101, the frequency of the noise to be targeted, etc.

[0014] When the length of the shaft 102 of the motor 101 shown in FIG. 1 in the shaft 102 direction is long, if a plane wave does not occur in the height of the chamber 202, that is, in the length of the shaft 102 of the motor 101 in the shaft 102 direction, depending on the noise target frequency, a plane wave can be realized by partitioning the space into a plurality of stages. The sound, which is a pressure fluctuation of air, caused by a non-decaying plane wave can be silenced by energy loss due to friction (conversion to heat energy due to friction) during the propagation of the pressure fluctuation.

[0015] As shown in FIG. 2, the chambers 202 in the muffler 201 are arranged radially around the motor 101. In the example of FIG. 2, there are four chambers 202. The shape and the number of divisions of the chamber 202 are determined using the following formula (1) based on constraints such as the size of the motor 101, the noise target frequency f1, the space of the electric equipment, mechanical device, etc. to which the motor 101 is attached.

[0016] For example, the vertical dimension a [m] × horizontal dimension b [m] of the size (area) of the thin plate 203 is the noise target frequency f1 [Hz] obtained by the following formula (1), the bulk modulus of air k [N / m 2 , the areal density m [kg / m 2 of the thin plate 203, the Young's modulus E, the plate thickness h [m], the Poisson's ratio τ, the speed of sound c [m / s 2], background air layer L [m] (see Figure 1), air density ρ [kg / m³] 3 It can be expressed by the following equation (1) using constants p and q. p and q are both approximately "0" and can be ignored.

number

[0017] The thin plate 203 forms a single vibration system with the air cavity 201k behind it, resulting in a peak in sound absorption coefficient at the resonant frequency. In particular, sound absorption is achieved through the resonance of the thin plate 203 at low frequencies. Specifically, the resonance frequency is in the low-frequency range, and by increasing the surface density m of the thin plate 203 and the air cavity 201k (=back air layer L) of the air layer, the frequency f1 to be silenced becomes even lower, according to equation (1). The slits 204 (see Figures 1 and 2) are provided to allow the thin plates 203 to vibrate more easily. One or more slits 204 are provided in each thin plate 203 that makes up each chamber 202.

[0018] Sound that cannot be absorbed by the thin plate 203 of the plate vibration type sound absorption described above passes through the thin plate 203 and the slit 204 and enters the room 202. The intrusion of sound (air pressure fluctuations) increases the air pressure in chamber 202, and the air in the slit 204 vibrates as it pushes back against the air pressure fluctuations caused by the sound.

[0019] <Effects and Effects> The air in the slit 204 vibrates, and the sound is silenced by frictional loss of air (conversion to thermal energy due to friction). By making this silencer a frequency different from f1 represented by equation (1), two frequencies can be silenced with a single silencer 201 structure. Therefore, the silencer 201 of the first embodiment can provide soundproofing against noise at two frequencies other than f1 represented by formula (1).

[0020] Therefore, by attaching a silencer 201 to the sound source (motor 101) that drives the fan or blower used in electrical equipment and mechanical products such as washing machines, vacuum cleaners, and refrigerators, the noise radiated from the sound source used in electrical equipment and mechanical products can be appropriately reduced. Furthermore, it is possible to achieve both cooling and noise reduction through the thermoacoustic effect.

[0021] <<Second Embodiment>> Figure 3 is a cross-sectional view of the motor 101 and silencer 201A when the motor 101 is attached to the silencer 201A according to a second embodiment of the present invention, cut in a cross-section perpendicular to the shaft 102 of the motor 101's rotation axis. Note that in Figure 3, the motor 101 is shown in a simplified manner. The silencer 201A of the second embodiment has a ring-shaped cylindrical form and is installed around the motor 101.

[0022] A cylindrical motor 101 is surrounded by a cylindrical thin plate 203a of an annular silencer 201A. The cylindrical thin plate 203a has two slits 204: a larger slit 204a and a smaller slit 204b. The other components are the same as in the first embodiment, so the same reference numerals are used for similar components, and detailed descriptions are omitted.

[0023] <Effects and Effects> In the second embodiment, the silencer 201A is formed in a cylindrical thin plate 203a with a large slit 204a and a small slit 204b, so that sound (air pressure fluctuations) enters the chamber 202 from the large slit 204a and the small slit 204b, respectively. As a result, the air in the large slit 204a vibrates, and the sound is silenced by frictional loss (conversion of sound into thermal energy due to friction during the propagation of air pressure fluctuations). Similarly, the air in the small slit 204b vibrates, and the sound is silenced by frictional loss (conversion of sound into thermal energy due to friction during the propagation of air pressure fluctuations).

[0024] In this way, by forming a large slit 204a and a small slit 204b in the cylindrical thin plate 203a, the frequency to be silenced can be divided into two. For example, this structure makes it possible to silence fluctuating sounds of multiple frequencies associated with fluctuations in the rotational speed (rotational speed) of the motor 101. As shown in Figure 3, the silencer 201A of the second embodiment can be housed within the same ring shape, so the silencer 201A can be made compact and small.

[0025] <<Third Embodiment>> Figure 4 is a side cross-sectional view of the silencer 201B according to the third embodiment of the present invention, as seen from the side when attached to the motor 101. In other words, Figure 4 is a side cross-sectional view of the silencer 201B as seen when the silencer 201B is attached to the motor 101, cut in the direction along the shaft 102 of the motor 101. The annular silencer 201B of the third embodiment is mounted around the cylindrical motor 101.

[0026] A fan or blower, which will act as a load on the motor 101, can be attached to the shaft 102 of the motor 101's rotating axis, as needed. The silencer 201B of the third embodiment has two internal cavities, chambers 202b1 and 202b2. The side of chamber 202b facing the motor 101 is in the shape of a thin cylindrical plate 203b. The thin plate 203b has a slit 204c. In this third embodiment, the depth dimension of chamber 202b is different between the depth dimension L1 of the upper chamber 202b1 and the depth dimension L2 of the lower chamber 202b2.

[0027] <Effects and Effects> By substituting L=L1 and L=L2 respectively into equation (1) above, it becomes possible to silence different frequencies f1 in the upper chamber 202b1 and the lower chamber 202b2 of the silencer 201B. For example, fans usually have covers installed. Therefore, it is thought that high-frequency sounds, especially those coming from below, are effectively shielded. Thus, by determining the size so that the lower section absorbs lower frequencies and the upper section absorbs higher frequencies, further noise reduction can be expected. In the third embodiment, an example is shown where the chamber 202b has a two-stage structure of chambers 202b1 and 202b2 aligned with the shaft 102 of the motor 101. However, there are no restrictions on the number of stages of the silencer 201B, and the number of stages can be changed depending on the size of the motor 101 and the frequency of the noise to be addressed.

[0028] <<Fourth Embodiment>> Figure 5 is an external perspective view of a drum-type washing machine and dryer 100 equipped with a silencer 201 (see Figure 7) according to the first embodiment of the present invention.

[0029] <Configuration of the 100-unit drum-type washer-dryer> The drum-type washing and drying machine 100 of the fourth embodiment shown in Figure 5 has an outer casing formed by a housing 1. The housing 1 is composed of a housing base 1a located at the bottom, side plates 1b located above the housing base 1a that cover both sides and a front cover 1c that covers the front, and a top cover 1d located at the top. The rear of the top cover 1d is provided with a water supply hose connection port 30, which has a male thread, for supplying water from a water tap to the drum-type washing machine 100. The door 2 is cantilevered and can be opened and closed by a hinge installed at the left end of the center of the front cover 1c. The door 2 can be opened forward by pulling the door release handle 2a towards the front, which releases the engagement of the locking mechanism. On the other hand, the door 2 can be locked and closed by pressing it against the front cover 1c, which engages the locking mechanism.

[0030] Figure 6 is a longitudinal cross-sectional view of a drum-type washing and drying machine 100 equipped with a silencer 201 (see Figure 7) according to the first embodiment of the present invention. The drum-type washer-dryer 100 has a bottomed cylindrical outer tub 17 with a roughly horizontal axis for storing water inside its casing 1. A bottomed cylindrical drum 21 with a roughly horizontal axis for holding laundry is inserted almost concentrically inside the outer tub 17. The circumferential surface of the drum 21 is provided with a number of dewatering holes 21b. The dewatering holes 21b are small holes that drain the wash water inside the drum 21 to the outer tub 17. Furthermore, the inner surface of the drum 21 is provided with multiple baffles 23. The baffles 23 extend in the front-to-back direction and are formed in a convex shape toward the center. The baffles 23 are arranged at intervals in the circumferential direction of the drum 21. The baffle 23 is a component used to perform a beating wash by lifting and dropping the clothes placed inside the drum 21.

[0031] The outer tank 17 is supported from the housing 1 by the elastic force of a tension coil spring 20 (see Figure 6). The elastic force of the tension coil spring 20 balances the forces and moments in the front-rear direction of the outer tank 17, preventing it from tilting forward or backward. The lower part of the outer tank 17 is supported by a vibration-damping member 28 fixed to the housing base 1a of the housing 1. The vibration-damping member 28 supports the outer tank 17 by the elastic force of a compression coil spring and the viscous damping force of the fluid flowing within the damper. The front cover 1c has a circular opening 1c1 for loading and unloading clothes, located approximately in the same center as the front opening 17o (see Figure 6) of the outer tub 17.

[0032] The control panel 3, located on the top of the enclosure 1 as shown in Figure 5, is equipped with a power switch 4 and an operation switch 5. The control panel 3 is electrically connected via wiring to the control unit 7 (see Figure 6), which is located inside the enclosure 1. The control unit 7 has peripheral circuits such as a microcomputer and A / D / D / A converters mounted on it. A corrugated drain hose 34 for draining washing water, rinse water, etc., is attached to the housing base 1a.

[0033] Behind the outer tank 17 shown in Figure 6, there is a motor 22 and a bearing 22j. The outer tank 17 is directly driven by the motor 22. The control unit 7 controls the rotational speed of the motor 22 using an inverter. The control unit 7 also acquires the sensor value (sensor current) of the vibration sensor 29, which is an acceleration sensor provided in the drum-type washing machine / dryer 100. During the spin-drying process of the drum-type washer-dryer 100, if the vibration amplitude (acceleration) of the outer tub 17 detected by the vibration sensor 29 exceeds a preset threshold (limit value for the vibration amplitude of the outer tub 17) due to an imbalance in the clothes loaded into the drum 21, the spin-drying process is temporarily suspended. The vibration amplitude is obtained by integrating the acceleration detected by the vibration sensor 29 twice.

[0034] After the dewatering process is temporarily paused, when the motor 22 is restarted, the drum 21 is driven to rotate in both forward and reverse directions. Specifically, the drum 21 rotates forward and reverse to untangle the clothes, correct any imbalances in the clothes, and then the dewatering process is restarted.

[0035] The opening 17o of the outer tank 17 and the opening 1c1 of the housing 1, as shown in Figure 6, are connected by a bellows 19 that expands and contracts in the front-to-back direction. The bellows 19 is made of an annular, flexible, elastic rubber material and seals the drum 21 with water by closing the door 2. The input opening (opening 1c1) of the housing 1, the opening 17o of the outer tub 17, and the opening 21o of the drum 21 are in communication with each other. Therefore, by opening the door 2, it is possible to put clothes in and take them out of the drum 21.

[0036] A water supply valve 31 is provided at the bottom of the water supply hose connection port 30 shown in Figure 6. One end of a water supply hose 32 for supplying water to the outer tank 17 is connected to the water supply valve 31. When the water supply valve 31 opens, water flows from the water supply hose connection port 30 into the water supply hose 32. The incoming water is supplied to the outer tank 17 via the detergent container 33. The detergent container 33 is pre-filled with detergent. Therefore, the detergent in the detergent container 33 is added to the outer tank 17 along with the water supplied from the water supply hose 32.

[0037] A drain valve 34a is provided in the drainage path of the drain hose 34 located at the bottom of the outer tub 17. When the drain valve 34a is closed, the water supplied to the outer tub 17 is stored inside the outer tub 17. On the other hand, when the drain valve 34a is opened, the laundry water stored in the outer tub 17 is drained outside the drum-type washer-dryer 100 through the drain hose 34.

[0038] <Operation of Drum-type Washer Dryer 100> Next, the operation of the drum-type washer-dryer 100 will be described. The operation of the drum-type washer-dryer 100 is performed by digital control by the control unit 7 (see Figure 6). In the drum-type washer-dryer 100 with the above configuration, the user first presses the power switch 4 (see Figure 5), which turns on the power to the control unit 7 and starts the drum-type washer-dryer 100. The user then pulls the door opening handle 2a (see Figure 5) to open the door 2 and puts clothes into the drum 21. After closing the door 2, the user operates the operation switch 5, for example, by selecting a wash course and pressing the start button to start the washing process.

[0039] In the washing process, the water supply valve 31 (see Figure 6) is opened, and water supplied from the water supply hose connection port 30 is supplied to the outer tub 17 along with the detergent via the water supply hose 32 and detergent container 33. At this time, the larger the amount of clothing capacity calculated based on the rotational speed (rotational speed) and current value of the motor 22 before water supply, the greater the amount of water supplied in the washing process. After water is supplied, the drum 21 is rotated forward, stopped, reversed, and stopped repeatedly for a predetermined time. During this process, the clothes are lifted by the baffles 23 and then dropped (beating action), which is repeated and enhances the cleaning power of the clothes.

[0040] After the washing process, a dewatering process is performed. In the dewatering process, the drum 21 is initially rotated at a low rotation speed (low rotation speed) so that the clothes do not stick to it. Once the clothes begin to spread out, the rotation speed of the drum 21 is gradually increased, and the clothes stick to the drum 21 due to centrifugal force. Once the clothes are stuck to the drum 21, the rotation speed (rotation speed) of the drum 21 is increased, and while passing through the resonance section (section near the natural frequency) of the outer tub 17 where the vibration of the outer tub 17 increases, it reaches the target rotation speed (rotation speed) and the water contained in the clothes is centrifuged and dewatered.

[0041] After the dewatering process, a rinsing process is performed. In the rinsing process, the water supply valve 31 (see Figure 6) is opened, and water supplied from the water supply hose connection port 30 is supplied into the outer tub 17 through the water supply hose 32 and detergent container 33. In the rinsing process, as with the washing process, the amount of water supplied increases as the calculated amount of clothing increases, as more detergent is impregnated into the clothing. Also, in the rinsing process, as with the washing process, the drum 21 repeats the operation of forward rotation, stopping, reverse rotation, and stopping. During this time, an agitation operation (beating rinse) is performed for a predetermined time in which the clothing lifted by the baffle 23 falls.

[0042] After the final dewatering process, a drying process is performed. In the drying process, the drum 21 rotates at an even lower speed (rotation speed) than in the washing process to loosen the clothes, while warm air is blown into the drum 21 from the blower unit 401 (see Figure 6) onto the clothes. This dries the clothes while reducing wrinkles (wrinkle removal).

[0043] <Blower unit 401 equipped with silencer 201> Figure 7 is an enlarged cross-sectional view of a blower unit 401 equipped with a silencer 201 according to the first embodiment of the present invention. A fan 103 is attached to the shaft 102 of the motor 101. The fan 103 is covered by a bottomed cylindrical fan casing 301. The fan casing 301 has an air intake (not shown). Air is drawn in from the air intake and circulated as drying air through a drying air passage (not shown), including the inside of the outer tank 17. The fan casing 301 is attached to the motor 101 via vibration-damping rubber 106 that suppresses vibrations of the fan casing 301. The ring-shaped silencer 201 of the first embodiment described above is attached around the motor 101.

[0044] <Effects and Effects> With the above configuration, electromagnetic noise caused by the motor's unique electromagnetic force radiated from the side of the motor 101 can be silenced by the diaphragm vibration type sound absorption and resonator type sound absorption described in the first embodiment. From the viewpoint of sound insulation, it is preferable to have no gap between the silencer 201 and the motor 101, but from the viewpoint of vibration isolation and to allow the thin plate 203 to vibrate as a diaphragm, it is preferable to leave a gap without contact. Therefore, it is necessary to make a comprehensive judgment based on the vibration noise characteristics of the side of the motor 101 to which it is attached, the material of the silencer 201, and the convection of air around the motor 101 and cooling by heat conduction from the motor 101 to the silencer 201.

[0045] For example, filling the gap between the motor 101 and the silencer 201 with a vibration-damping material, such as rubber, which is a relatively soft elastic material, can achieve both sound insulation and vibration isolation. By mounting the silencer 201 on motor equipment such as a blower unit 401 having a motor 101, noise from the motor 101 can be reduced. As described above, by equipping the drum-type washing machine 100 with a blower unit 401, a drum-type washing machine 100 can be realized that reduces noise from the motor 101.

[0046] <<Other Embodiments>> 1. Note that the shape of any of the silencers 201, 201A, and 201B described in the first to fourth embodiments above does not have to be substantially cylindrical; they may be rectangular or polygonal. By making them rectangular, curved surfaces are eliminated, making manufacturing easier and improving productivity.

[0047] 2. Any of the silencers 201, 201A, and 201B described in the first to fourth embodiments above can be widely applied to electrical appliances other than washing machines, such as refrigerators, air conditioners, vacuum cleaners, and robotic vacuums. This makes it possible to obtain noise-reduced electrical appliances such as refrigerators, air conditioners, vacuum cleaners, and robotic vacuums.

[0048] 3. The present invention is not limited to the embodiments and modified configurations described above, and various modified and specific forms are possible within the scope of the appended claims. [Explanation of symbols]

[0049] 100 Drum-type washing machine and dryer (washing machine, electrical appliance) 101 Motor (sound source) 102 Shaft 103 Fans 201 Silencer Room 202 203 Thin plates (walls, membranes) 204 Slit 401 Blower unit (fan motor unit, motor equipment) L1, L2 depth dimensions

Claims

1. Formed around the sound source, A room in which space is defined, The chamber is formed by a wall body having a slit, The aforementioned slits are arranged in multiple locations in the circumferential direction of the sound source, with the slits facing the sound source. The aforementioned wall is composed of a thin plate or film. A silencer characterized by the following features.

2. In the silencer according to claim 1, The silencer is formed in a cylindrical shape around the sound source. A silencer characterized by the following features.

3. In the silencer according to claim 1, The aforementioned slits are composed of multiple sizes. A silencer characterized by the following features.

4. In the silencer according to claim 1, The aforementioned chambers are arranged in multiple stages, each facing the aforementioned sound source. A silencer characterized by the following features.

5. In the silencer according to claim 4, The multiple levels of the aforementioned chambers have different depth dimensions relative to the sound source. A silencer characterized by the following features.

6. The aforementioned sound source is a motor, A motor device having a silencer according to any one of claims 1 to 5.

7. A fan that is attached to the rotating shaft of the motor, The aforementioned fan is attached to a casing that has an intake port and an exhaust port, The silencer according to any one of claims 1 to 5 is mounted on the motor, The casing and the motor are connected. A fan motor unit characterized by the following features.

8. The fan motor unit described in claim 7 is installed. A washing machine characterized by the following features.

9. An electrical device comprising a silencer according to any one of claims 1 to 5.

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