Patent Description:
Generally, autonomous cleaning device cleans specific areas such as houses and offices by sucking dust or foreign matters while moving.

<CIT> provides a machine, a sweeping robot and a noise reduction air duct device of the sweeping robot. The noise reduction air duct device includes an air duct shell provided with an air inlet and an air outlet, and a noise reduction assembly which is arranged in the air duct shell and defines an air duct penetrating through the air inlet and the air outlet, and the edge, facing the airduct, of the noise reduction assembly is in a streamline shape to serve as the side wall of the air duct. The noise reduction air duct device can greatly reduce the noise of the air duct device.

<CIT> discloses an exhaust system including an exhaust fan and an exhaust pipe communicated with the exhaust fan, and the inlet end of the exhaust pipe is connected with the outlet end of the exhaust fan. The included angle between the inlet direction defined by the inlet end of the exhaust pipe and the outlet direction defined by the outlet end of the exhaust pipe ranges from <NUM> degrees to <NUM> degrees, two or more outlet flow deflectors are arranged at the end of the outlet end of the exhaust pipe, and the extending direction of the outlet flow deflectors is parallel to the outlet direction defined by the outlet end of the exhaust pipe. Viewed from the projection direction from the inlet end of the exhaust pipe to the outlet end of the exhaust pipe, the projection is completely shielded by the outlet flow deflectors, and the port of the outlet end of the exhaust pipe cannot be seen.

<CIT> discloses a noise reduction assembly and a sweeping robot. The sweeping robot includes a machine body, a fan body, a driving wheel assembly and a rolling brush assembly, the fan body, the driving wheel assembly and the rolling brush assembly are arranged on the machine body, and the noise reduction assembly includes at least two of an air duct noise reduction structure, a fan noise reduction structure, a motor noise reduction structure and a gear driving noise reduction structure; the fan noise reduction structure is connected between the fan body and the machine body; the air duct noise reduction structure is arranged in an air duct of the fan body and used for conducting noise reduction on airflow of the air duct. According to the motor noise reduction structure, a motor of the fan body is arranged to be a brushless motor. The gear driving noise reduction structure is arranged in the machine body and forms a noise reduction cavity for isolating a gear set of the drive wheel assembly and/or a gear set of the rolling brush assembly. According to the technical scheme, noise generated when the sweeping robot works is reduced, and the using comfort of the sweeping robot is improved.

In view of the above shortcomings and deficiencies in a related art, the present invention provides an autonomous cleaning device and a noise reduction air duct device thereof, which solves the technical problems that an existing autonomous cleaning device working in the high-power mode produces loud noise.

To this end, a main technical solution adopted by the present invention is described as follows:
According to a first aspect, embodiments of the present invention provide a noise reduction air duct device for an autonomous cleaning device. The autonomous cleaning device includes a body and a motor mounted on the body, the noise reduction air duct device is configured to be mounted on the body; the noise reduction air duct device an upper housing, a lower housing and a support noise reduction structure made of an elastic material, the lower housing and the upper housing enclose to form an air duct, the air duct comprises an air inlet at a position corresponding to the motor, and the air duct comprises an air outlet at a side of the air duct away from the air inlet; the support noise reduction structure comprises a first end fixed on the lower housing, and a second end abutting against a lower surface of the upper housing.

Optionally, the lower housing is configured to be fixed to the body, the lower housing comprises a groove, the upper housing is mounted at an opening of the groove, and the first end of the support noise reduction structure is fixed on a bottom face of the groove.

Along an airflow direction in the air duct, the air duct is divided into a first air duct and a second air duct downstream of the first air duct; a plurality of support noise reduction structures are mounted in the first air duct, the second air duct comprises an airflow buffer and an exhaust port, a first end of the airflow buffer is connected to the first air duct, the second end of the airflow buffer is connected to a first end of the exhaust port, and a second end of the exhaust port is located at a position of the air outlet.

Optionally, the support noise reduction structure is sheet-shaped, made of a sound deadening material and arranged along the airflow direction; and/or three or more support noise reduction structures are provided, and a number of the support noise reduction structures close to the air inlet is more than a number of the support noise reduction structures close to the second air duct.

Optionally, the lower housing at the airflow buffer includes a first inclined portion and a second inclined portion arranged successively along the airflow direction, the first inclined portion and the second inclined portion forms a smooth transition therebetween, and a side of the first inclined portion away from the second inclined portion is connected with the first air duct; an angle between the first inclined portion and the upper housing is greater than an angle between the second inclined portion and the upper housing; and/or along the airflow direction, a cross-sectional area of a part of the second air duct enclosed by the lower housing at the airflow buffer and the upper housing gradually increases.

Optionally, the exhaust port is horn-shaped, and includes a third inclined portion and a fourth inclined portion; the third inclined portion and the fourth inclined portion forms a smooth transition therebetween, a side of the third inclined portion away from the fourth inclined portion is snapped with the second inclined portion of the airflow buffer; and/or a second end of the exhaust port is provided with a vibration-damping structure.

Optionally, the support noise reduction structure is made of EPP noise reduction material, and an inner wall of the air duct is coated with the EPP noise reduction material; and/or a corner of the air duct is rounded for a smooth transition.

Optionally, the noise reduction air duct device further includes an active noise reduction located close to the motor, the active noise reduction is configured to generate an inversed phase acoustic-wave equal to noise of the motor, to neutralize the noise of the motor.

Optionally, the active noise reduction includes a microphone, a speaker, and a noise elimination circuit; the microphone is configured to collect a noise signal of the motor and transmit the noise signal to the noise elimination circuit in real time, the noise elimination circuit is configured to control the speaker to generate an inverted acoustic-wave according to the received noise signal.

According to a second aspect, embodiments of the present invention provide an autonomous cleaning device. The autonomous cleaning device includes the above noise reduction air duct device.

The following is the beneficial effect of the present invention: the noise reduction air duct for the autonomous cleaning device of the present invention is provided with the support noise reduction structure between the upper housing and the lower housing, compared with the related art, the noise reduction air duct of the autonomous cleaning device may absorb the vibration of the upper housing when the airflow passes through, and achieve the effect of reducing the operational noise of the vacuum device.

The present invention further improves the structure of the noise reduction air duct. By providing the airflow buffer and the exhaust port, the impact of the airflow is reduced, and the friction between the airflow and the air duct is also reduced, thereby reducing the noise generated during cleaning.

autonomous cleaning device; <NUM>. body; <NUM>. upper cover; <NUM>. motor; <NUM>. air outlet; <NUM>. dust box; <NUM>. air duct assembly; <NUM>. upper housing; <NUM>. lower housing; <NUM>. air inlet; <NUM>. airflow buffer; <NUM>. support noise reduction structure; <NUM>. exhaust port; <NUM>. active noise reduction; <NUM>. first inclined portion; <NUM>. second inclined portion; <NUM>. third inclined portion; <NUM>. fourth inclined portion; <NUM>. vibration-damping structure.

In order to better explain the present invention and facilitate understanding, the present invention is described in detail through specific embodiments in combination with the accompanying drawings. Terms such as "up", "down" and other directional nouns mentioned in the present invention refer to orientations in <FIG>.

The autonomous cleaning device includes a unit of an ordinary vacuum cleaner for sucking dust or foreign matters, a mobile unit for moving the autonomous cleaning device, a detection sensor for detecting various obstacles in an area to be cleaned, and a controller for performing cleaning operations. The controller controls the mobile unit and the detection sensor to clean.

The autonomous cleaning device travels in the area to be cleaned, such that a floor may be cleaned autonomously without user's operation. Specifically, the autonomous cleaning device may have an effect of removing dust or cleaning the house floor. The dust herein may include, for example, dust, dirt, powder and debris.

The autonomous cleaning device includes a vacuum device to form a vacuum state. Solid particles are drawn into a dust box through a vacuum suction port. A filter in the dust box filters airflow, and the airflow passes through an air duct to enter a vacuum generator (motor) and then is discharged out of the autonomous cleaning device. In a related art, when the autonomous cleaning device cleans in a high-power mode, due to an increased vacuum degree, enhanced friction and impact between the airflow and the air duct cause a large physical vibration, resulting in loud noise and affecting the user experience.

Thus, there is an urgent need to provide an autonomous cleaning device capable of reducing noise and a noise reduction air duct device thereof.

Referring to <FIG>, <FIG> and <FIG>, embodiments of the present invention provide a noise reduction air duct device for an autonomous cleaning device. The autonomous cleaning device <NUM> includes a body <NUM>, a noise reduction air duct device and an upper cover <NUM>. The body <NUM> is provided with a dust box <NUM> and a motor <NUM>, the noise reduction air duct device is mounted on the body <NUM>, and the upper cover <NUM> covers the noise reduction air duct device. The motor <NUM> is a vacuum-pumping motor for sucking solid particles on the ground.

The noise reduction air duct device includes an air duct assembly <NUM>, and the air duct assembly <NUM> includes an upper housing <NUM>, a lower housing <NUM> and a support noise reduction structure <NUM> made of elastic material. The lower housing <NUM> and the upper housing <NUM> enclose to form an air duct <NUM>.

An air inlet <NUM> is arranged at a position of the lower housing <NUM> corresponding to the motor <NUM>, and an air outlet <NUM> is arranged on a side of the lower housing <NUM> away from the air inlet <NUM>.

An end of the support noise reduction structure <NUM> is fixed on the lower housing <NUM>, and the other end of the support noise reduction structure <NUM> abuts against a lower surface of the upper housing <NUM>.

Further, the lower housing <NUM> is fixed to the body <NUM>, the lower housing <NUM> defines a groove <NUM>, the upper housing <NUM> is mounted at an opening <NUM> of the groove <NUM>, and an end of the support noise reduction structure <NUM> is fixed on a bottom face of the groove <NUM>.

Along a flow direction of airflow in the air duct <NUM>, the air duct <NUM> is divided into a first air duct <NUM> and a second air duct <NUM> downstream of the first air duct <NUM>. A plurality of support noise reduction structures <NUM> are mounted in the first air duct <NUM>, and the support noise reduction structures <NUM> are arranged between the bottom face of the groove <NUM> and the upper housing <NUM>. An end of the support noise reduction structure <NUM> is fixed on the bottom face of the groove <NUM> of the lower housing <NUM>, and the other end of the support noise reduction structure <NUM> abuts against the lower surface of the upper housing <NUM>. The support noise reduction structure <NUM> forms an elastic support for the upper housing <NUM> to absorb the vibration of the upper housing <NUM> when the airflow passes through to reduce the noise. A cross section of the first air duct <NUM> perpendicular to the flow direction of the airflow is strip-shaped, such that the manufacturing and processing of the first air duct <NUM> are simple, and the friction resistance of the first air duct <NUM> to the airflow is low.

The support noise reduction structure <NUM> is sheet-shaped, made of sound deadening material and arranged along the airflow direction, which is conducive to guiding the airflow to the second air duct <NUM>. In addition, there are three or more support noise reduction structures <NUM>, and the number of the support noise reduction structures <NUM> close to the air inlet <NUM> is greater than the number of the support noise reduction structures close to the second air duct <NUM>. Speed of the airflow at the air inlet <NUM> is higher than speed of the airflow close to the second air duct <NUM>. The arrangement of more support noise reduction structures <NUM> may better absorb the vibration from the upper housing <NUM> at the air inlet <NUM>, to reduce the noise.

Further, the support noise reduction structure <NUM> is made of EPP noise reduction material, and a surface of the groove <NUM> of the lower housing <NUM> and a lower surface of the upper housing <NUM> are coated with EPP noise reduction material. It should be noted that EPP is a polypropylene plastic foaming material, which has excellent sound insulation and absorption effect, and has the advantages of light specific gravity, good elasticity, shock resistance and compression resistance, high deformation recovery rate, good absorption performance, resistance to various chemical solvents, insulation, heat resistance, environmental protection and so on.

In addition, in order to further reduce the friction between the airflow and the air duct <NUM>, a corner of the air duct <NUM> is rounded for a smooth transition.

The second air duct <NUM> is provided with an airflow buffer <NUM> and an exhaust port <NUM>. As shown in <FIG>, <FIG> and <FIG>, the lower housing <NUM> at the airflow buffer <NUM> includes a first inclined portion <NUM> and a second inclined portion <NUM> arranged successively along the airflow direction. There is a smooth transition between the first inclined portion <NUM> and the second inclined portion <NUM>, and a side of the first inclined portion <NUM> away from the second inclined portion <NUM> is connected with the first air duct <NUM>. Since the airflow buffer <NUM> has increased space relative to the first air duct <NUM>, the airflow slows down after reaching the airflow buffer <NUM>, thereby reducing an airflow impact on the exhaust port <NUM> and reducing noise. An angle between the first inclined portion <NUM> and the upper housing <NUM> is greater than an angle between the second inclined portion <NUM> and the upper housing <NUM>. A flow rate of the airflow decreases rapidly at the first inclined portion <NUM>, and the rate of decrease in the flow rate is reduced at the second inclined portion <NUM>, and the airflow gradually tends to be gentle and stable, such that adjustment rate in the flow rate at each area of the second air duct <NUM> are reasonably adjusted, to reduce the exhaust noise.

Along the airflow direction, the groove <NUM> at the airflow buffer <NUM> is gradually narrowed in width, but gradually increased in height, and a cross-sectional area of a part of the second air duct <NUM> enclosed by the lower housing <NUM> at the airflow buffer <NUM> and the upper housing <NUM> gradually increases. Since the airflow buffer <NUM> has increased space relative to the first air duct <NUM>, the airflow slows down after reaching the airflow buffer <NUM>, thereby reducing the airflow impact on the exhaust port <NUM> and reducing noise. It should be noted that in addition to the way of narrowing the width and increasing the height of the groove <NUM>, the cross-sectional area of the second air duct <NUM> at the airflow buffer <NUM> may also be gradually increased by other appropriate ways. In addition, an inner surface of the airflow buffer <NUM> is coated with the EPP noise reduction material.

Referring to <FIG>, <FIG>, the exhaust port <NUM> is horn-shaped, and an outer wall of the exhaust port <NUM> is fixedly connected with the lower housing <NUM> through two screws. The exhaust port <NUM> includes a third inclined portion <NUM> and a fourth inclined portion <NUM>. There is a smooth transition between the third inclined portion <NUM> and the fourth inclined portion <NUM>, a side of the third inclined portion <NUM> away from the fourth inclined portion <NUM> is snapped with the second inclined portion <NUM> of the airflow buffer <NUM>, and a vibration-damping structure <NUM> is arranged at the other end of the exhaust port <NUM> to avoid vibration and noise caused by high-speed airflow directly passing through an exhaust hole. Specifically, in a preferred embodiment shown in <FIG>, the vibration-damping structure <NUM> is a sponge sheet directly facing the air outlet, to avoid the noise caused by the high-speed airflow passing through the exhaust hole, and the airflow is buffered by the sponge sheet and discharged to the exhaust hole through pores on the sponge sheet and finally discharged to the outer atmosphere. The sponge sheet may further filter the dust that may remain in the exhaust airflow, to avoid the exhaust air from polluting the external environment. When the airflow impacts the air duct <NUM>, turbulent noise may occur, and the vibration-damping structure <NUM> may reduce the vibration at the position of the air outlet <NUM> of the air duct <NUM> and further reduce the noise.

In addition, an inner surface of the exhaust port <NUM> is coated with EPP noise reduction material.

Combined with <FIG>, the noise reduction air duct device also includes an active noise reduction <NUM>, and the active noise reduction <NUM> is located close to the motor <NUM>. The active noise reduction <NUM> may generate an inverted phase acoustic-wave equal to the noise of the motor <NUM>, and then neutralize the noise to achieve active noise reduction for the noise of the motor <NUM>.

Specifically, the active noise reduction <NUM> includes a microphone, a speaker, and a noise elimination circuit. The microphone collects a noise signal of the motor <NUM> and transmits the noise signal to the noise elimination circuit in real time. The noise elimination circuit controls the speaker to generate an inverted acoustic-wave signal according to the received noise signal to counteract the noise of the motor <NUM>.

Referring to <FIG>, <FIG>, <FIG> and <FIG>, embodiments of the present invention also provide an autonomous cleaning device, including a body <NUM>, the above noise reduction air duct device and an upper cover <NUM>. The body <NUM> is provided with a dust box <NUM> and a motor <NUM>, the noise reduction air duct device is mounted on the body <NUM>, and the upper cover <NUM> covers the noise reduction air duct device.

The autonomous cleaning device also includes a cleaning system, a sensing system, a control system, a driving system, an energy system and a man-machine interaction system. Major components of the autonomous cleaning device are described in detail below.

The body <NUM> includes a frame, a front portion, a rear portion, a chassis, and the like. The body <NUM> is in an approximate circular shape (both front and rear are circular), and may also be in other shapes, including but not limited to an approximate D-shape with a squared-shape in front and a circular-shape in rear.

The sensing system includes a position sensor located above the body <NUM>, and a sensing device such as a buffer, an obstacle avoidance sensor, an infrared sensor, a magnetometer, an accelerometer, a gyroscope, and an odometer, located at the front portion of the body <NUM>. These sensing devices provide various position information and motion state information of a machine to the control system. In a preferred embodiment, the position sensor includes, but is not limited to, a laser transmitter, a vision camera, a dynamic vision sensor, or a laser ranging device (LDS).

The cleaning system includes a dry cleaning portion and a wet cleaning portion. The wet cleaning portion is a first cleaning portion, and is mainly configured to wipe a surface to be cleaned (such as the ground) with a cleaning cloth containing a cleaning liquid. The dry cleaning portion is a second cleaning portion, and is mainly configured to clean solid particle pollutants on the surface to be cleaned through a structure such as a cleaning brush.

As the dry cleaning portion, the main cleaning function comes from the second cleaning portion composed of a roller brush, a dust box, a fan, an air vent and connecting components among them. The roller brush with certain interference with the ground sweeps up particles on the ground and rolls them to the front of the dust suction port between the main brush and the dust box, and then the particles are sucked into the dust box by suction gas that is generated by the fun and passes through the dust box. Dust removal capacity of a sweeper may be characterized by the dust pick up efficiency (DPU). The dust pick up efficiency DPU is affected by structure and material of the roller brush, by wind utilization rate of the air duct <NUM> composed of the dust suction port, the dust box <NUM>, the fan, the air vent and the connecting components among them, and by type and power of the fan. The dry cleaning system may also include an edge brush having a rotating shaft, the rotating shaft is at an angle relative to the ground for moving debris into a cleaning area of the main brush of the second cleaning portion.

As the wet cleaning portion, the first cleaning portion mainly includes a liquid container, a cleaning cloth, and the like. The liquid container serves as a base for carrying other components of the first cleaning portion. The cleaning cloth is detachably arranged on the liquid container. Liquid in the liquid container flows to the cleaning cloth, and the cleaning cloth wipes the ground after cleaned by the roller brush and the like.

The driving system is configured to drive the body <NUM> and components thereon to move for automatic walking and cleaning. The driving system includes a driving wheel module. The driving system may send a drive command based on distance and angle information to operate the autonomous cleaning device to travel across the ground. The driving wheel module may control a left wheel and a right wheel synchronously. In order to control movement of the machine more accurately, it is preferred that the driving wheel module includes a left driving wheel module and a right driving wheel module, respectively, and the left driving wheel module and the right driving wheel module are opposed (arranged symmetrically) along a transverse axis defined by the body <NUM>. In order to enable the autonomous cleaning device to move more stably or have stronger movement ability on the ground, the autonomous cleaning device may include one or more driven wheels, including but not limited to universal wheels.

The driving wheel module includes a walking wheel, a driving motor and a control circuit configured to control the driving motor. The driving wheel module may also be connected with a circuit for measuring a driving current and an odometer. The driving wheel module may be detachably connected to the body <NUM> to facilitate disassembly, assembly and maintenance. The driving wheel may have a biased-falling suspension system, and the biased-falling suspension system is fastened to the body <NUM> in a movable manner, such as rotatably attached to the body <NUM>, and receives spring bias to be biased downward and away from the body <NUM>. The spring bias allows the driving wheel to maintain contact with the ground and traction with a certain ground grip, and cleaning elements of the autonomous cleaning device (such as the roller brush) also contact the ground with a certain pressure.

The front portion of the body <NUM> may carry the buffer. During the cleaning, when the driving wheel module pushes the autonomous cleaning device to walk on the ground, the buffer detects one or more incidents along a walking path of the autonomous cleaning device via a series of trigger principles, such as light breaking principle. The autonomous cleaning device may control the driving wheel module based on the incidents, such as obstacles or walls, detected by the buffer, to make the autonomous cleaning device respond to the incidents, such as moving away from the obstacles,.

Generally, during using the autonomous cleaning device, in order to prevent the autonomous cleaning device from entering restricted areas in the house, for example, areas where fragile articles are placed or water containing areas on the ground such as the toilet. Preferably, the autonomous cleaning device for cleaning also includes a restricted area detector. The restricted area detector includes a virtual wall sensor which sets a virtual wall according to user's arrangement to define the restricted area. When detecting the virtual wall, the virtual wall sensor may control the driving wheel module to restrict the autonomous cleaning device for cleaning from crossing a boundary of the restricted area, i.e., the virtual wall, and entering the restricted area.

In addition, during using the autonomous cleaning device, in order to prevent the autonomous cleaning device from falling at places such as indoor stairs and higher steps, the restricted area detector also includes a cliff sensor which sets a boundary according to user's arrangement to define the restricted area. When detecting the boundary of the restricted area, i.e., an edge of the cliff, the cliff sensor may control the driving wheel module to restrict the autonomous cleaning device for cleaning from crossing the boundary of the restricted area, to avoid the autonomous cleaning device from falling down from the steps.

The control system is arranged on the circuit main board in the body <NUM>, including a calculation processor, such as a central processing unit and an application processor, communicating with non-temporary memory, such as a hard disk, flash memory, random access memory. The application processor uses a positioning algorithm, such as SLAM, to draw a real-time map of an environment where the autonomous cleaning device is located, according to obstacle information fed back by a laser ranging device. In combination with the distance information and speed information fed back by the buffer, cliff sensor, ultrasonic sensor, infrared sensor, laser sensor, magnetometer, accelerometer, gyroscope odometer or other sensing devices, a current working state of the sweeper, such as crossing a threshold, moving to a carpet, being located at the cliff, the upper portion or the lower potion being stuck, and the dust box being full, being picked up and so on, is comprehensively determined. Furthermore, a specific next action strategy can also be given according to different situations, such that the work of the autonomous cleaning device may better meet owner's requirements and have better user experience. Further, the control system may plan the most efficient and reasonable cleaning path and cleaning method based on the real-time map information drawn based on SLAM, which greatly improves cleaning efficiency of the autonomous cleaning device.

The energy system includes a rechargeable battery, such as a lithium battery and a polymer battery. The rechargeable battery may be connected with a charging control circuit, a battery pack charging temperature detection circuit and a battery undervoltage monitoring circuit. The charging control circuit, the battery pack charging temperature detection circuit and the battery undervoltage monitoring circuit are then connected with a single-chip microcomputer control circuit. The machine is connected with a charging pile through a charging electrode arranged on a side or below of the machine body for charging. If a bare charging electrode is stained with dust, the plastic machine body around the electrode melts and deforms due to charge accumulation effect during the charging, and even the electrode itself is deformed and unable to continue normal charging.

The autonomous cleaning device is provided with a signal receiver at a front end to receive a signal sent by the charging pile. The signal is usually an infrared signal. In some more advanced technologies, the signal may be a graphic signal. Generally, when the autonomous cleaning device starts from the charging pile, the system remembers a location of the charging pile. Thus, when the autonomous cleaning device finishes the cleaning or the power is low, the autonomous cleaning device will control the driving wheel system to drive it to the location of the charging pile stored in its memory, and then go to the charging pile to charge.

The man-machine interaction system includes keys on a machine panel for user to select functions, and may further include a display screen and/or an indicator light and/or a speaker. The display screen, indicator light and speaker show the user a current state of the machine or functional options. The man-machine interaction system may also include a mobile client program. For a path navigation cleaning apparatus, the mobile client program may show the user a map of an environment where the autonomous cleaning device stays during moving, and a location of the machine, to provide the user with richer and humanized function items.

In order to more clearly describe behaviors of the autonomous cleaning device, the following directions are defined: the autonomous cleaning device may travel on the ground through various combinations of movements relative to the following three mutually perpendicular axes defined by the body <NUM>: a front-rear axis X, i.e., an axis extending along a direction of a front portion and a rear portion of the body <NUM>; a transverse axis Y, i.e., an axis perpendicular to the axis X and in the same horizontal plane as the axis X; and a central vertical axis Z, i.e., an axis perpendicular to a plane composed of the axis X and the axis Y A forward driving direction along the front-rear axis X is marked as "forward " and a backward driving direction along the front-rear axis X is marked as "backward ". The transverse axis Y is essentially extends between the right wheel and the left wheel of the autonomous cleaning device along an axle center defined by a center point of the driving wheel module.

The autonomous cleaning device may rotate around the Y axis. When the forward part of the autonomous cleaning device tilts upward and the rearward part tilts downward, the autonomous cleaning device is "pitch up", and when the frontward part of the autonomous cleaning device tilts downward and the rearward part tilts upward, the autonomous cleaning device is "pitch down". In addition, the autonomous cleaning device may rotate around the Z axis. In the forward direction of the autonomous cleaning device, when the autonomous cleaning device tilts to the right of the X axis, the autonomous cleaning device is "right-turn", and when the autonomous cleaning device tilts to the left of the X axis, the autonomous cleaning device is "left-turn".

The dust box is mounted in an accommodating chamber at a rear portion of the machine body part in a form of mechanical latch snap-fit. When the latch is pressed, a clip is retracted, and when the latch is released, the clip sticks out to be snap-fitted in a groove <NUM>, configured to accommodate the clip, in the accommodating chamber.

Compared with the related art, since the support noise reduction structure is provided between the upper housing <NUM> and the lower housing <NUM>, the noise reduction air duct device for the autonomous cleaning device of the present invention may absorb the vibration of the upper housing <NUM> when the airflow passes through, and achieve the technical effect of reducing the noise caused by the motor.

In the description of the present invention, it should be understood that the terms such as "first" and "second" are used herein for purposes of description and are not intended to indicate or imply relative importance or significance or to imply the number of indicated technical features. Thus, the feature defined by "first" and "second" may comprise one or more of this feature. In the description of the present invention, "a plurality of" means two or more than two, unless specified otherwise.

In the present invention, it should be noted that, unless specified otherwise, terms "mounted", "coupled", "connected" and "fixed" should be understood broadly, for example, may be fixed connections, detachable connections, or integral connections; may also be mechanical or electrical connections or intercommunications; may also be direct connections or indirect connections via intervening structures; may also be inner communications or interactions of two elements, which may be understood by those skilled in the related art according to specific situations.

Claim 1:
A noise reduction air duct device for an autonomous cleaning device, the autonomous cleaning device comprising a body (<NUM>) and a motor (<NUM>) mounted on the body (<NUM>), the noise reduction air duct device being configured to be mounted on the body (<NUM>) and the noise reduction air duct device comprising:
an upper housing (<NUM>);
a lower housing (<NUM>); and
a support noise reduction structure (<NUM>),
wherein the support noise reduction structure (<NUM>) is made of an elastic material, the lower housing (<NUM>) and the upper housing (<NUM>) enclose to form an air duct (<NUM>), the air duct (<NUM>) comprises an air inlet (<NUM>) at a position corresponding to the motor (<NUM>), and the air duct (<NUM>) comprises an air outlet (<NUM>) at a side of the air duct (<NUM>) away from the air inlet (<NUM>); and the support noise reduction structure (<NUM>) comprises a first end fixed on the lower housing (<NUM>), and a second end abutting against a lower surface of the upper housing (<NUM>),
characterized in that
along an airflow direction in the air duct (<NUM>), the air duct (<NUM>) is divided into a first air duct (<NUM>) and a second air duct (<NUM>) downstream of the first air duct (<NUM>); and
a plurality of support noise reduction structures (<NUM>) are mounted in the first air duct (<NUM>), the second air duct (<NUM>) is provided with an airflow buffer (<NUM>) and an exhaust port (<NUM>), a first end of the airflow buffer (<NUM>) is connected to the first air duct (<NUM>), a second end of the airflow buffer (<NUM>) is connected to a first end of the exhaust port (<NUM>), and a second end of the exhaust port (<NUM>) is located at a position of the air outlet (<NUM>).