Work Machine

Abstract

To restrict air-blowing sound as false sound (i.e. fluid pressure fluctuation) from being collected by a microphone.SOLUTION: A working machine has a passage extending into a housing from an opening. The passage is arranged to control an air flow to be generated by machine motion. The working machine includes a microphone. The microphone collects in-housing sound including operation sound to be generated inside the housing by the machine motion. The working machine also includes a structure for forming a storage space of the microphone along the passage where the operation sound is propagated to the outside of the housing. The structure has an opening structure, which connects the storage space to the passage and is directed to a downstream side of the passage and encloses the storage space on an upstream side of the passage upper than the opening structure.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates to a work machine. [Background technology]

[0002] The following Patent Document 1 discloses a power tool to which active noise control (ANC) is applied. ANC is a technology that uses sound collected by a microphone to generate a sound with an opposite phase at a position where the sound is to be silenced, thereby canceling noise. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2019 / 0275657 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, a sound signal output as an electric signal from a microphone by collecting sound may contain a wind noise component that is a spurious sound (i.e., a fluid pressure fluctuation). The wind noise component as a spurious sound contained in the sound signal may have an undesirable effect on the execution result of processing based on the sound signal.

[0005] For example, wind noise components contained in a sound signal as spurious sounds are not the kind of noise components audible to the ears of a user of the work machine, and may have an undesirable effect on noise reduction by ANC. Even when detecting an abnormality in a work machine based on a sound signal, wind noise components may cause the accuracy of the abnormality detection to deteriorate.

[0006] Therefore, one aspect of the present disclosure has an object to suppress collection of wind noise (in other words, spurious noise) by a microphone in a work machine in which operating sounds within a housing are collected by the microphone. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, there is provided a work machine comprising: a machine; the machine is configured to move for a predetermined task; the work machine comprises: a housing; the housing at least partially houses the machine; and the housing comprises an opening.

[0008] The work machine includes a passageway extending from the opening into the housing. The passageway is provided to control airflow caused by machine motion. The work machine includes a microphone. The microphone is configured to collect sounds within the housing, including operating sounds caused within the housing by machine motion, and to output a sound signal, which is an electrical signal corresponding to the collected sounds.

[0009] The working machine includes a processor configured to execute processing related to the operation sound based on a sound signal from the microphone, and the working machine further includes a structure that defines a space for accommodating the microphone along a passage through which the operation sound propagates to the outside of the housing.

[0010] According to one aspect of the present disclosure, the microphone is disposed in an accommodation space within the housing, and the structure has an opening structure connecting the accommodation space and a passage, the opening structure facing downstream of the passage, and surrounds the accommodation space upstream of the passage from the opening structure.

[0011] With a work machine configured in this manner, when the operating sounds within the work machine that may propagate outside the housing through the opening via the airflow control passage are collected by a microphone, it is possible to prevent the microphone from collecting wind noise (in other words, spurious noise). [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a perspective view showing the appearance of a dust collector. [Diagram 2] FIG. [Diagram 3]1 is a perspective view of a rear housing with parts removed, as viewed from a joining surface side with the front housing. FIG. [Figure 4] FIG. 2 is a perspective view showing the internal state with the rear housing removed from the dust collector body. [Diagram 5] 1 is a perspective view of a front housing with parts removed, as viewed from a joining surface side with a rear housing; FIG. [Figure 6] 13 is an enlarged plan view of a portion of a front housing including parts related to a partition wall, as viewed from the joining surface side with the rear housing. FIG. [Figure 7] 13 is an enlarged plan view of a portion of the rear housing as viewed from the joint surface side with the front housing. FIG. [Figure 8] 2 is a cross-sectional view perpendicular to the up-down direction of the dust collector body. FIG. [Figure 9] FIG. 2 is a block diagram showing an electrical configuration of the dust collector. [Figure 10] FIG. 1 is a block diagram showing a feedforward ANC model. [Figure 11] FIG. 11A is a diagram illustrating a microphone housing structure according to a first modified example, and FIG. 11B is a diagram illustrating a microphone housing structure according to a second modified example. [Figure 12] 13A and 13B are diagrams illustrating a microphone housing structure according to a third modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] [1. Overview of the embodiment] The work implement in some embodiments may include a machine. The machine may be configured to move for a given task. Additionally or alternatively, the work implement may include a housing. The housing may at least partially house the machine. The housing may include an opening.

[0014] Additionally or alternatively, the implement may include a passageway. The passageway may be positioned to extend from the opening into the housing. The passageway may be provided to control airflow caused by machine motion.

[0015] Additionally / alternatively, the work machine may include a microphone. The microphone may be positioned to collect sounds within the housing. The microphone may collect sounds within the housing, including operational sounds generated within the housing by machine movement. The microphone may be configured to output a sound signal, which is an electrical signal corresponding to the collected sound.

[0016] Additionally / alternatively, the work machine may include a processing unit. The processing unit may be configured to execute processing based on the sound signal from the microphone. For example, the processing unit may be configured to execute processing related to the operation sound based on the sound signal from the microphone.

[0017] Additionally / alternatively, the work machine may include a structure that forms a space for accommodating the microphone. The structure may form the space for accommodating the microphone along the passage. Operation sound may propagate to the outside of the housing through the passage.

[0018] In some embodiments, the microphone may be disposed in the accommodation space within the housing. In some embodiments, the structure may have an opening structure facing downstream of the passageway. The opening structure may connect the accommodation space and the passageway. The structure may surround the accommodation space upstream of the passageway from the opening structure. The structure may be positioned to restrict the progression of airflow from the passageway upstream of the opening structure to the accommodation space.

[0019] In an embodiment, the structure may include a partition. The partition may define a containment space. The partition may extend from a sidewall of the passage. The partition may define the containment space between the sidewall of the passage and the partition. The partition may enclose the containment space between the sidewall of the passage and the partition.

[0020] In some embodiments, the partition may extend from a side wall of the passageway downstream away from the side wall, and the partition may utilize the side wall to enclose a storage space between the side wall and the partition downstream of the passageway from a connection point between the side wall and the partition.

[0021] In some embodiments, the partition may include a first wall element connected to and extending away from a sidewall of the passage. The partition may include a second wall element extending downstream of the passage from the first wall element. The partition may be positioned to restrict ingress of airflow from upstream of the passage into the storage space through an opening structure between a downstream end of the partition and the sidewall of the passage.

[0022] In one embodiment, the partition wall can extend over the entire height of the passageway from the floor of the passageway to the ceiling upstream of the opening structure and cover the storage space. The partition wall that extends over the entire height can effectively suppress the advancement of airflow from the upstream of the passageway from the opening structure to the storage space. Therefore, the microphone can collect the operating sounds inside the work machine while suppressing the collection of unwanted wind noise.

[0023] In one embodiment, the structure may be provided to cover the entire passage upstream of the opening structure of the storage space. Such a structure can suppress unwanted wind noise from being picked up by the microphone.

[0024] In one embodiment, the work machine may include a windshield that covers the periphery of the microphone. The microphone may be disposed in the storage space while being covered by the windshield. In one embodiment, the work machine may include a porous material for rectifying a flow that covers a side surface of the partition opposite to a side surface facing the storage space.

[0025] In one embodiment, the work machine may include a speaker. The processing related to the operation sound may include processing for causing the speaker to output a control sound for suppressing propagation of the operation sound outside the housing. By causing the speaker to output the control sound based on a sound signal with a small wind noise component, it is possible to effectively generate a control sound for canceling out the operation sound while suppressing a control error due to the wind noise component.

[0026] In one embodiment, the passage may be an exhaust passage for directing airflow generated by machine motion out of the housing. The opening may be an exhaust port. The microphone accommodation space may be formed along the exhaust passage.

[0027] According to this example, the operation noise attempting to propagate to the outside of the housing through the exhaust passage can be appropriately collected by the microphone while suppressing the effects of wind noise. Therefore, when performing control to cancel the operation noise with a control sound, it is possible to effectively generate a control sound for canceling the operation noise while suppressing control errors due to wind noise components.

[0028] One or more of the multiple components constituting the above-mentioned working machine may be optionally deleted. Additional elements may be optionally provided in the working machine. One or more of the multiple components constituting the working machine may be optionally replaced with other elements.

[0029] 2. SPECIFIC EXEMPLARY EMBODIMENTS [2.1. Dust collector configuration] As an example of a working machine, the configuration of a dust collector 1 will be described below. In this embodiment, for convenience of description, front, rear, upper, lower, left, and right are defined relative to the dust collector 1 as shown in Figs.

[0030] 1, the dust collector 1 of this embodiment includes a main body 3, an operating device 6, and a wearing device 7. The wearing device 7 includes shoulder belts 71A, 71B, and a waist belt 72. The shoulder belts 71A, 71B and the waist belt 72 are attached to the rear of the main body 3.

[0031] The shoulder belts 71A, 71B extend from near the upper end and both left and right ends of the main body 3. The waist belt 72 extends from near the lower end of the main body 3. The wearing tool 7 is used by the worker to carry the main body 3 on his back.

[0032] The operating device 6 includes a switch for starting and stopping the dust collector 1, and is operated by an operator. The operating device 6 is connected to the vicinity of the center of the lower end of the main body 3 via a cable 61.

[0033] The main body 3 includes a housing 30 for accommodating electrical and / or mechanical main components of the dust collector 1. The housing 30 includes a rear housing 301, a front housing 302, and a plate 303. The configuration of the rear housing 301 is shown in Figures 2 and 3. The configuration of the front housing 302 is shown in Figures 4 and 5.

[0034] The rear housing 301 is a bottomed box-shaped member having an inner surface facing forward. The front housing 302 is a frame-shaped member having an opening. The plate 303 is a plate-shaped member that closes the opening of the front housing 302 from the front. The housing 30 is molded, for example, by injection molding a resin material.

[0035] As shown in Figures 3, 4, and 5, the housing 30 includes a suction port 31, a dust collection chamber 32, a first flow path 33, a motor chamber 34, a second flow path 35, a third flow path 36, a partition wall 37, a first battery accommodating section 38A, a second battery accommodating section 38B, and a component placement section 39.

[0036] Suction port 31 is provided in the center of the upper end of housing 30. A first end of a flexible hose (not shown) is connected to suction port 31. A second end of the hose is connected to a nozzle (not shown) having a suction port.

[0037] 4, the dust collection chamber 32 is a rectangular internal space provided in the upper part of the housing 30. The dust collection chamber 32 accommodates a dust collection pack 41 connected to the suction port 31. The dust collection pack 41 is, for example, a paper pack, and collects dust sucked in through the suction port 31.

[0038] The first flow path 33 is provided along the right side of the dust collection chamber 32, and has a lower end connected to the motor chamber 34. A filter 42 is disposed at the boundary between the first flow path 33 and the dust collection chamber 32. The filter 42 is, for example, a high efficiency particulate air filter (HEPA).

[0039] The motor chamber 34 is an internal space provided below the dust collection chamber 32. As shown in Figures 6 and 7, the motor chamber 34 has an inlet 341 to which the first flow path 33 is connected at the center of the right end, and an outlet 342 to which the second flow path 35 is connected at the upper left end. A driving machine 43 is housed in the motor chamber 34. The thick arrows in Figures 6 and 7 conceptually represent airflow.

[0040] The driving machine 43 includes a fan 431, a motor 432, and a damper 433. The fan 431 is connected to a rotating shaft of the motor 432, and rotates by receiving power from the motor 432, thereby generating an airflow from the inlet 341 to the outlet 342 of the motor chamber 34.

[0041] The damper 433 is an annular member that covers the periphery of the motor 432 and absorbs sound generated by the motor 432. In Fig. 4, the motor 432 is not shown because it is covered by the damper 433, but is located at the center of the damper 433. Fig. 8 shows the arrangement of the motor 432.

[0042] The second flow passage 35 is an exhaust passage provided above the motor chamber 34 and extending leftward from the motor chamber 34. The second flow passage 35 connects the outlet 342 of the motor chamber 34 and the third flow passage 36.

[0043] The third flow path 36 is an exhaust passage provided on the left side of the motor chamber 34, extending downward, and has an exhaust port 361 at its downstream portion. As shown in Figures 2 and 7, the exhaust port 361 has the form of a group of slits formed in the rear surface of the housing 30. The arrows from the exhaust port 361 in Figure 2 conceptually represent the exhaust from the exhaust port 361 to the outside of the housing 30.

[0044] The second flow path 35 and the third flow path 36 form an L-shaped exhaust passage and control the airflow from the motor chamber 34 to the exhaust port 361. Specifically, the second flow path 35 and the third flow path 36 guide the airflow from the motor chamber 34 to the outside of the housing 30 through the exhaust port 361.

[0045] The partition wall 37 extends downward from an upper side wall 35A extending leftward of the second flow passage 35, in a direction perpendicular to the side wall 35A. The partition wall 37 extends downward, in other words, toward the downstream of the exhaust passage, away from the side wall 35A of the second flow passage 35, at a predetermined distance from the left side wall 36A extending downward of the third flow passage 36.

[0046] 5, the partition wall 37 is provided upright from a surface of the front housing 302 facing the rear housing 301 toward the rear housing 301. Thus, the partition wall 37 is provided along the third flow path 36 so as to extend over the entire height of the third flow path 36 from the ceiling to the bottom surface, as shown in FIG.

[0047] With this arrangement, the partition 37 forms an accommodation space for the microphone 53 along the exhaust passage, particularly along the third flow path 36. That is, the partition 37 functions as a structure that forms the accommodation space for the microphone 53. In Fig. 5, the microphone 53 arranged in the accommodation space is indicated by a dotted line.

[0048] Specifically, the partition wall 37 defines an accommodation space for the microphone 53 between itself and the side walls 35A and 36A. The partition wall 37 surrounds the accommodation space for the microphone 53 together with the side wall 35A of the second flow passage 35 and the side wall 36A of the third flow passage 36 downstream of the connection point with the side wall 35A of the second flow passage 35 in the exhaust passage.

[0049] A lower end of partition 37, in other words the downstream end, forms an opening structure between side wall 36A of third flow path 36 and the storage space for microphone 53 and third flow path 36. The storage space for microphone 53 is surrounded by partition 37, side wall 35A of second flow path 35, side wall 36A of third flow path 36, the bottom surface of rear housing 301, and the inner surface of front housing 302 without leakage from the front, rear, left, right, and above all over the upstream of the exhaust passage by the opening structure.

[0050] The microphone 53 is accommodated in the accommodation space between the partition 37 and the side walls 35A and 36A, surrounded from all sides by the porous material 530 that functions as a windshield. In Fig. 4, the microphone 53 hidden by the porous material 530 is indicated by a dotted line.

[0051] The porous material 530 has a shape corresponding to the accommodation space of the microphone 53, and almost fills the accommodation space of the microphone 53 except for the portion where the microphone 53 is exactly located. A porous material 37C for rectifying airflow is attached to the entire right surface of the partition 37, which is opposite to the left surface facing the side wall 36A. In Fig. 7, the arrangement of the partition 37, the microphone 53, the porous material 530, and the porous material 37C in the rear housing 301 is indicated by dotted lines.

[0052] Examples of the porous material include a fiber-based sound-absorbing base material and a foam-based sound-absorbing base material. Examples of the fiber-based sound-absorbing base material include glass wool, rock wool, and polyester fiber nonwoven material. Examples of the foam-based sound-absorbing base material include foamed polyurethane. For the porous material 530, a material suitable for a windshield may be selected from the above specific materials. For the porous material 37C, a material suitable for rectifying the flow may be selected from the above specific materials. When selecting the material, the use environment, resistance, cost, and the like may be taken into consideration. For the porous material 530 and the porous material 37C, a foam-based sound-absorbing base material, for example, foamed polyurethane, may be used.

[0053] The microphone 53 is used as a reference microphone in the ANC. Hereinafter, the microphone 53 will be referred to as the reference microphone 53. The reference microphone 53 is disposed in the housing 30 to collect sounds in the housing 30, including the operating sound of the dust collector 1 generated in the housing 30 due to mechanical movement in the housing 30. The reference microphone 53 outputs a sound signal, which is an electrical signal corresponding to the collected sound.

[0054] The operating noise collected by the reference microphone 53 is noise (hereinafter referred to as target noise) that should be controlled by ANC so as to be attenuated outside the housing 30. The target noise includes noise generated from the motor 432 and the fan 431 of the drive machine 43, and noise generated by airflow generated by the movement of the drive machine 43.

[0055] The reference microphone 53 is installed in the above-mentioned accommodation space along the exhaust passage so as to efficiently and appropriately collect the target noise propagating to the outside of the housing 30 through the exhaust passage and the exhaust port 361 .

[0056] In the main body 3 configured in this manner, when an airflow is generated by the movement of the driving machine 43, outside air is sucked into the internal space of the housing 30 through the suction port 31. The sucked outside air first enters the dust collection chamber 32 and passes through the dust collection pack 41 attached to the suction port 31. As the air passes through this way, dust contained in the outside air is captured.

[0057] The air that has passed through the dust collection pack 41 reaches the first flow path 33 via the filter 42. The air that has reached the first flow path 33 passes through the motor chamber 34 and the second flow path 35 to reach the third flow path 36, and is discharged to the outside of the housing 30 via the exhaust port 361.

[0058] A part of the operation sound attempting to propagate to the outside of the housing 30 through the exhaust port 361 is collected as target noise by the reference microphone 53. As described above, an opening structure for guiding the operation sound to the reference microphone 53 is provided between the partition wall 37 and the side wall 36A. Therefore, the operation sound is appropriately collected by the reference microphone 53 through the opening structure and the porous material 530.

[0059] The space housing the reference microphone 53 is completely surrounded in all directions except the direction facing the opening structure upstream of the opening structure, and is isolated from the main line of the exhaust passage. Therefore, almost no airflow occurs in the space housing the reference microphone 53 compared to the exhaust passage, and wind noise as a pseudo sound collected by the reference microphone 53 is greatly reduced.

[0060] In addition, the first battery accommodating section 38A of the housing 30 is a space for accommodating the first battery pack 45A, and is provided near the lower end of the housing 30 and has a first battery mounting port 381A that opens near the lower left end of the housing 30.

[0061] The second battery accommodating section 38B is a space that accommodates the second battery pack 45B, and is provided near the lower end of the housing 30, with a second battery attachment port 381B that opens near the lower right end of the housing 30. The first and second battery packs 45A, 45B are inserted into the first and second battery accommodating sections 38A, 38B through the first and second battery attachment ports 381A, 381B, respectively.

[0062] The component placement section 39 is an internal space located between the motor chamber 34, the second flow path 35, the third flow path 36, and the first and second battery storage sections 38A, 38B, and various electrical components are placed therein.

[0063] The component placement section 39 has a vertically elongated section 391 surrounded on three sides by the walls of the motor chamber 34, the second flow path 35, and the third flow path 36, and a horizontally elongated section 392 sandwiched between the motor chamber 34 and the first and second battery storage sections 38A, 38B and communicating with the vertically elongated section 391.

[0064] A connector 52 is disposed in the horizontally elongated portion 392. The connector 52 is disposed between the first battery housing portion 38A and the second battery housing portion 38B, and is provided for connecting a cable 61 of the operating device 6 to an internal circuit.

[0065] A control speaker 54 and an error microphone (hereinafter, error microphone) 55 used for ANC, and the drive controller 44 are disposed in the vertically elongated portion 391. The control speaker 54 and the error microphone 55 are attached using attachment holes 304, 305 formed on the bottom surface of the rear housing 301 so that the directivities of the control speaker 54 and the error microphone 55 face outward from the housing 30.

[0066] 4, the drive controller 44 is attached to the wall surface that is the boundary between the vertically elongated portion 391 and the motor chamber 34. The drive controller 44 is a circuit board that performs power supply control, motor control, noise control, etc., and will be described in detail later.

[0067] Error microphone 55 is placed near exhaust port 361 which is the mute point, that is, at a position where error microphone 55 can be considered to be at the mute point and where it is not directly hit by the airflow generated by driving machine 43.

[0068] The control sound is output from the control speaker 54 to cancel the target noise. The reference microphone 53, the control speaker 54, and the error microphone 55 are arranged so that the time it takes for the control sound emitted from the control speaker 54 to reach the muffling point is shorter than the time it takes for the target noise to directly reach the muffling point. In other words, the process of generating the control sound is executed during this time difference.

[0069] The control speaker 54 emits a control sound toward the outside of the housing 30. The error microphone 55 collects a sound obtained by combining the target noise and the control sound, which is discharged from the exhaust port 361. The control speaker 54 has the ability to emit a sound that is sufficiently louder than the target noise. The error microphone 55 has the ability to receive the combined sound of the target noise and the control sound without distortion.

[0070] [2.2. Drive controller] As shown in FIG. 9, the drive controller 44 includes a control circuit 441, a dust collection circuit group 442, a noise circuit group 443, and a power supply circuit 447.

[0071] The power supply circuit 447 distributes the power supplied from the first and second battery packs 45A and 45B to each section at an appropriate voltage. The control circuit 441 is configured as a microcomputer. The control circuit 441 includes a CPU 441A and a memory 441B.

[0072] As another example, the control circuit 441 may include a combination of electronic components such as discrete elements instead of or in addition to a microcomputer. The control circuit 441 may include a digital signal processor (DSP) and / or an application specific integrated circuit (ASIC). The control circuit 441 may include an application specific standard product (ASSP). The control circuit 441 may include a programmable logic device.

[0073] The dust collection circuit group 442 includes circuits necessary for performing the functions of the dust collector 1. Specifically, the dust collection circuit group 442 includes a motor drive circuit and a battery switching circuit. The motor drive circuit is a circuit that drives the motor 432. The battery switching circuit is a circuit for appropriately switching the power supply source to either the first and second battery packs 45A and 45B according to the remaining charge amounts of the first and second battery packs 45A and 45B.

[0074] The noise circuit group 443 is various circuits necessary for performing the functions of a noise control device. The noise circuit group 443 includes first and second analog / digital (A / D) converters 444 and 445 and a digital / analog (D / A) converter 446.

[0075] The first A / D converter 444 A / D-converts the sound signal from the reference microphone 53 and supplies it to the control circuit 441. The second A / D converter 445 A / D-converts the sound signal from the error microphone 55 and supplies it to the control circuit 441. The D / A converter 446 generates a control signal that D / A-converts the control data from the control circuit 441 and supplies it to the control speaker 54.

[0076] By controlling the dust collection circuit group 442, the control circuit 441 executes a noise suppression process for suppressing target noise as a process related to the operating sound in addition to the process of realizing the functions of the dust collector 1.

[0077] The control circuit 441 realizes a feedforward type active noise control (ANC) by executing a noise control process. The ANC causes the control speaker 54 to output a control sound for suppressing the propagation of the operation sound outside the housing 30, in other words, a control sound for canceling the target noise.

[0078] [2.3.ANC model] 10, a model of a feedforward ANC applied to the dust collector 1 will be described. The feedforward ANC model includes a reference sensor M1, a control sound source M2, an error sensor M3, a noise control filter M4, a secondary system filter M5, and a coefficient update unit M6.

[0079] The reference sensor M1 corresponds to the reference microphone 53 and the first A / D converter 444. The control sound source M2 corresponds to the D / A converter 446 and the control speaker 54. The error sensor M3 corresponds to the error microphone 55 and the second A / D converter 445.

[0080] The noise control filter M4, the secondary filter M5, and the coefficient update unit M6 can all be realized by processing of the control circuit 441. Alternatively, some or all of the noise control filter M4, the secondary filter M5, and the coefficient update unit M6 can be realized by hardware.

[0081] The reference sensor M1 collects the target noise to generate a reference signal x n Generate a reference signal x n corresponds to a digital signal generated by sampling the sound signal from the reference microphone 53 at a predetermined sampling period. n represents discrete time, and the corresponding reference signal x n represents the nth sampling data.

[0082] The noise control filter M4 is an FIR filter including L taps, where L is a positive integer. The noise control filter M4 filters the L most recently detected reference signals {x n ,x n-1 ,…,x n-L+1}, the control signal u n Generate.

[0083] The control sound source M2 receives the control signal u n The error sensor M3 collects the composite sound of the target noise and the control sound to generate an error signal e n Generates an error signal e n corresponds to a digital signal generated by sampling the sound signal from the error microphone 55 at a predetermined sampling period.

[0084] Hereinafter, the propagation path of the sound from the reference sensor M1 to the error sensor M3 is called the primary system, and the propagation path of the sound from the control sound source M2 to the error sensor M3 is called the secondary system. The secondary system filter M5 is an FIR filter including N taps, where N is a positive integer. The secondary system filter M5 filters the most recently detected N reference signals {x n ,x n-1 ,…,x n-N+1} to the N-dimensional reference vector x(n) n Generate.

[0085] The secondary filter M5 is a filter that models the transfer characteristics of the secondary system, and a fixed value is used for the coefficient of each tap. n is the influence of the secondary system added to the control sound when the control sound reaches the error sensor M3, expressed as the reference signal x n This is the signal given to

[0086] The coefficient update unit M6 updates the filtered reference signal r n and the error signal e n Based on this, at the position of the error sensor M3 (i.e., the sound attenuation point), the target noise and the control sound cancel each other out, and the error signal e n The coefficients {w 1 ,w 2 ,…,w L} to update.

[0087] The coefficients of the noise control filter M4 can be updated using, for example, the Filtered-x NLMS algorithm, which is one of the adaptive algorithms. By updating the coefficients, the target noise is attenuated outside the housing 30 so that it is cancelled by the control sound.

[0088] [2.4. Effect of dust collector] The dust collector 1 of the present embodiment described above provides the following advantages. (2.4.1) Operational sounds generated within the housing 30 of the dust collector 1 and leaking out of the housing 30 through the exhaust port 361 are collected by a reference microphone 53 provided along the exhaust passage. A control sound is output from a control speaker 54 to cancel out the operation sounds propagating to the outside of the housing 30. This makes it possible to effectively prevent the operation sounds of the dust collector 1 from reverberating around as unpleasant noise.

[0089] (2.4.2) The partition wall 37 that forms the storage space for the reference microphone 53 suppresses the advancement of airflow toward the reference microphone 53. This effectively suppresses the wind noise component as a pseudo sound in the sound signal of the reference microphone 53 used to generate the control sound. This effectively suppresses the deterioration of the cancellation effect of the operation sound by the control sound caused by the wind noise component. This makes it possible to configure a dust collector 1 that produces small operation sounds that reach the user's ears.

[0090] (2.4.3) An opening structure is provided at the end of the partition wall 37 so that the operation sound of the object to be collected by the reference microphone 53 can be transmitted to the reference microphone 53. The opening structure faces the downstream side of the exhaust passage, and can suppress the airflow flowing through the exhaust passage from proceeding toward the reference microphone 53.

[0091] (2.4.4) The partition 37 extends over the entire height of the exhaust passage, and the housing space for the reference microphone 53 is covered so as to be isolated from the surroundings throughout the entire area upstream of the opening structure. Therefore, the progress of airflow into the housing space for the reference microphone 53 can be effectively suppressed. The operating noise that tends to propagate to the outside of the housing 30 through the exhaust passage can be appropriately collected by the reference microphone 53 while suppressing the effects of wind noise. The effects of wind noise collected by the reference microphone 53 on ANC can be effectively suppressed.

[0092] (2.4.5) The side walls 35A, 36A of the exhaust passage are utilized to form a space for accommodating the reference microphone 53 between the partition wall 37 and the side walls 35A, 36A. Therefore, a structure capable of effectively suppressing wind noise of the reference microphone 53 can be formed in the housing 30 at low cost.

[0093] (2.4.6) The reference microphone 53 is accommodated in the accommodation space while being wrapped in the porous material 530 that functions as a windshield. The porous material 530 covers the periphery of the reference microphone 53. Therefore, the wind noise component is more effectively suppressed.

[0094] (2.4.7) A porous material 37C for rectifying airflow is provided on the surface of the partition 37 opposite to the surface facing the storage space for the reference microphone 53. The porous material 37C is effective in suppressing interference between the partition 37 and turbulent airflow generated upstream of the partition 37. When the porous material 37C is provided, noise caused by airflow is more effectively suppressed than when the porous material 37C is not provided.

[0095] [3. Modifications] [3.1. First modified example] In the above-described dust collector 1, the partition wall 37 may be changed to a partition wall 371 having a structure shown in Fig. 11A. In Fig. 11A, the configuration of the exhaust passage and its surroundings of the dust collector 1 in the first modified example is simply shown.

[0096] The partition wall 371 of the first modification includes a first wall element 371A and a second wall element 371B. The first wall element 371A is connected to the side wall 36A of the third flow passage 36 and extends away from the side wall 36A. Specifically, the first wall element 371A extends obliquely downstream of the third flow passage 36 from the connection portion with the side wall 36A at an angle with respect to the side wall 36A.

[0097] The second wall element 371B extends from the first wall element 371A toward the downstream of the third flow passage 36. The second wall element 371B extends parallel to the side wall 36A of the third flow passage 36 at a position spaced a predetermined distance from the side wall 36A.

[0098] This partition 371 also surrounds the storage space for the reference microphone 53 between itself and the sidewall 36A to define the storage space. The partition 371 extends over the entire height of the third flow path 36 from the ceiling to the bottom surface and covers the storage space. The partition 371 forms an opening structure between itself and the sidewall 36A, and is configured so that the reference microphone 53 arranged in the storage space can appropriately collect operation sounds through the opening structure.

[0099] The reference microphone 53 is placed in the accommodation space with its periphery covered by the porous material 531 serving as a windshield. The partition wall 371 includes a porous material 371C for rectifying the flow on the surface opposite to the surface of the reference microphone 53 facing the accommodation space.

[0100] 11A, the porous material 531 and the porous material 371C are indicated by dashed lines. The porous material 531 has a shape corresponding to the storage space formed between the partition wall 371 and the side wall 36A, and almost fills the storage space around the reference microphone 53. The porous material 371C is attached to the entire surface of the reference microphone 53 opposite to the surface facing the storage space.

[0101] The first modified example also makes it possible to suppress the intrusion of airflow from upstream of the opening structure into the accommodation space of the reference microphone 53, and makes it possible to effectively suppress the wind noise component in the sound signal of the reference microphone 53.

[0102] [3.2. Second Modification] In the dust collector 1 described above, the partition wall 37 may be changed to a partition wall 372 having a structure shown in Fig. 11B. The partition wall 372 of the second modification includes a first wall element 372A and a second wall element 372B.

[0103] The first wall element 372A is connected to the side wall 36A of the third flow passage 36 and extends to the right so as to be perpendicularly away from the side wall 36A. The second wall element 372B extends from the first wall element 372A toward the downstream of the third flow passage 36. The second wall element 372B extends parallel to the side wall 36A of the third flow passage 36 at a position spaced a predetermined distance from the side wall 36A.

[0104] This partition 372 also surrounds the storage space for the reference microphone 53 between itself and the sidewall 36A to define the storage space. The partition 372 extends over the entire height of the third flow path 36 from the ceiling to the bottom surface and covers the storage space. The partition 372 forms an opening structure between itself and the sidewall 36A, and is configured so that the reference microphone 53 arranged in the storage space can appropriately collect operation sounds through the opening structure.

[0105] The reference microphone 53 is placed in the storage space with its periphery covered by a porous material 532 serving as a windshield. The porous material 532 has a shape corresponding to the storage space formed between the partition wall 372 and the side wall 36A, and almost fills the storage space around the reference microphone 53.

[0106] The partition 372 includes a porous material 372C for rectifying flow on a surface opposite to a surface facing the accommodation space of the reference microphone 53. The porous material 372C is attached to the entire surface opposite to the surface facing the accommodation space of the reference microphone 53. In Fig. 11B, the porous material 532 and the porous material 372C are represented by dashed lines.

[0107] The second modified example also makes it possible to suppress the intrusion of airflow from upstream of the opening structure into the accommodation space of the reference microphone 53, and makes it possible to effectively suppress the wind noise component in the sound signal of the reference microphone 53.

[0108] [3.3.Third Modification] As shown in FIG. 12, the above-described dust collector 1 may be provided with an exhaust passage 363 curved in an arc instead of the second flow path 35 and the third flow path 36 that constitute an L-shaped exhaust passage.

[0109] 12 may be provided in the exhaust passage 363 instead of the partition 37. The partition 373 of the third modification is connected to the side wall 363A of the exhaust passage 363 upstream of the curved portion 363C of the exhaust passage 363, and extends from the connection portion along the curved portion 363C of the exhaust passage 363 to the downstream of the exhaust passage 363.

[0110] The partition 373 is disposed so as to be spaced farther from the side wall 363A as it approaches the downstream of the exhaust passage 363. With this arrangement, a space for accommodating the reference microphone 53 is formed between the partition 373 and the side wall 363A of the exhaust passage 363.

[0111] That is, the partition 373 surrounds the storage space of the reference microphone 53 between itself and the side wall 363A to define the storage space. The partition 373 also extends over the entire height of the exhaust passage 363 from the ceiling to the bottom surface and covers the storage space. The partition 373 forms an opening structure between itself and the side wall 363A, and is configured so that the reference microphone 53 can favorably collect operation sound through the opening structure.

[0112] The reference microphone 53 can be placed in the storage space with its periphery covered by a porous material 533 serving as a windshield. The porous material 533 has a shape corresponding to the storage space and almost fills the storage space around the reference microphone 53.

[0113] The partition 373 includes a porous material 373C for rectifying flow on a surface opposite to a surface facing the accommodation space of the reference microphone 53. The porous material 373C is attached to the entire surface opposite to the surface facing the accommodation space of the reference microphone 53. In Fig. 12, the porous material 533 and the porous material 373C are represented by dashed lines.

[0114] The third modified example also makes it possible to suppress the intrusion of airflow from upstream of the opening structure into the accommodation space of the reference microphone 53, and makes it possible to effectively suppress the wind noise component in the sound signal of the reference microphone 53.

[0115] [4.Other] (4.1) According to the above-described embodiment including the modified examples, the output from the microphone 53 is used for ANC. However, the output from the microphone 53 may be used for detecting an abnormality in the dust collector 1 based on the operating sound of the dust collector 1. In this case, the control speaker 54 and the error microphone 55 do not need to be provided inside the dust collector 1.

[0116] (4.2) The technology of the present disclosure is not limited to application to the dust collector 1. The technology of the present disclosure may be applied to a working machine that is used in a work site such as DIY, manufacturing, gardening, and / or construction, and uses an airflow generated by a fan. The technology of the present disclosure may be applied to a gardening working machine and / or a working machine that prepares the environment of the work site. For example, the technology of the present disclosure may be applied to various electric working machines such as an electric lawn mower, an electric lawn trimmer, an electric brush cutter, an electric cleaner, an electric blower, an electric sprayer, an electric spreader, and an electric dust collector.

[0117] (4.3) Multiple functions possessed by one component in the above embodiments may be realized by multiple components, or one function possessed by one component may be realized by multiple components. Multiple functions possessed by multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Part of the configurations of the above embodiments may be omitted. At least part of the configurations of the above embodiments may be added to or substituted for the configurations of other of the above embodiments. [Explanation of symbols]

[0118] 1... Dust collector, 3... Main body, 30... Housing, 31... Suction port, 32... Dust collection chamber, 33... First flow path, 34... Motor chamber, 35... Second flow path, 35A, 36A, 363A... Side walls, 36... Third flow path, 37, 371, 372, 373... Partition walls, 37C, 371C, 372C, 373C... Porous materials, 43... Driving machine, 44... Drive controller, 45A... First battery pack, 45B... Second battery pack, 53... Reference microphone, 54... Control speaker, 55... Error microphone, 301... Rear housing, 302... Front housing, 303... Plate, 304, 305... Mounting holes, 341... Inlet, 342... Outlet, 361... Exhaust port, 363... Exhaust passage, 363C... Curved portion, 371A, 372A... First wall elements, 371B, 372B... Second wall elements, 431... Fan, 432... Motor, 433... Damper, 441... Control circuit, 441A... CPU, 441B... Memory, 442... Dust collection circuit group, 443... Noise circuit group, 444, 445... A / D converters, 446... D / A converter, 447... Power supply circuit, 530, 531, 532, 533... Porous materials, M1... Reference sensor, M2... Control sound source, M3... Error sensor, M4... Noise control filter, M5... Secondary system filter, M6... Coefficient update unit.

Claims

1. a machine configured to move for a predetermined task; a housing for at least partially housing the machine, the housing having an opening; a passageway extending from said opening into said housing for controlling airflow caused by movement of said machine; a microphone configured to collect sounds within the housing, including operational sounds generated within the housing due to the movement of the machine, and to output a sound signal, which is an electrical signal corresponding to the collected sounds; A processing unit configured to execute a process related to the operation sound based on the sound signal from the microphone; a structure that defines a space for accommodating the microphone along the passage through which the operation sound propagates to the outside of the housing; Equipped with The microphone is disposed in the receiving space within the housing, The structure has an opening structure that connects the storage space and the passage and faces downstream of the passage, and the work machine surrounds the storage space so that no air flow is generated upstream of the passage from the opening structure through the structure and into the storage space.

2. 2. The work machine according to claim 1, wherein the structure includes a partition wall extending from a side wall of the passage toward downstream of the passage, away from the side wall, and the side wall is utilized to enclose the storage space between the side wall and the partition downstream of the passage from a connection point between the side wall and the partition.

3. 2. The work machine according to claim 1, wherein the structure includes a partition including a first wall element connected to a side wall of the passage and extending away from the side wall, and a second wall element extending from the first wall element downstream of the passage, and encloses the storage space between the side wall and the partition.

4. The work machine according to any one of claims 1 to 3, wherein the structure covers the entire upstream side of the passage from the opening structure of the accommodation space.

5. 4. The work machine according to claim 2 or 3, wherein the partition wall extends across the entire height of the passage from a bottom surface of the passage to a ceiling upstream of the opening structure, and covers the storage space.

6. A windshield is provided to cover the periphery of the microphone, The work machine according to any one of claims 1 to 5, wherein the microphone is arranged in the accommodation space while being covered by the windshield.

7. A windshield for covering the microphone; a porous material for straightening a flow that covers a side surface of the partition wall opposite to a side surface facing the storage space; Equipped with 6. The work machine according to claim 2, 3 or 5, wherein the microphone is arranged in the accommodation space while being covered by the windshield.

8. Equipped with a speaker, 8. The work machine according to claim 1, wherein the processing related to the operation sound includes processing for causing the speaker to output a control sound for suppressing propagation of the operation sound outside the housing.

9. the passage is an exhaust passage for guiding the airflow generated by the movement of the machine to the outside of the housing, and the opening is an exhaust port; The work machine according to any one of claims 1 to 8, wherein the housing space for the microphone is formed along the exhaust passage.

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