Patent Description:
Leaf blowers are mainly used for blowing away fallen leaves, road surface dust, accumulated water and accumulated snow, etc. Common types of blower include centrifugal blowers and axial-flow blowers. Centrifugal blowers generally comprise a housing and, installed in the housing, an electric motor and a centrifugal fan. The housing has an air inlet, an air outlet and a channel connecting the air inlet and the air outlet, with the centrifugal fan being located in the passage. Under the driving of the electric motor, the centrifugal fan generates a high-pressure airflow, which exits through the air outlet in order to perform blowing. The electric motor used in the centrifugal blower has a large volume, and consequently the blower has a high overall weight.

Axial-flow blowers generally comprise a housing and, installed in the housing, an electric motor and an axial-flow fan. The electric motor drives the axial-flow fan to rotate, pushing air entering the blower to move in the axial direction of the blower, such that the air is expelled from an extremity of a blow pipe. Compared with the centrifugal blower, the axial-flow blower is lighter in weight and has better heat dissipation performance, because the airflow flows through the electric motor in the process of passing through the blower, and can have the effect of cooling the electric motor.

The <CIT> discloses portable centrifugal blower having an air concentrator nozzle for increasing air velocity exiting from blower tube, wherein the air concentrator nozzle is positioned in the lower housing between the motor and the downward air inlet. The <CIT> describes an axial hairdryer having a casing, a motor with a motor casing and a fan, wherein a curved windshield is positioned between the motor casing and an air inlet defined by an outwardly tapering portion of the dryer casing. The <CIT> refers to a backpack hairdryer having a blower body and the blower tube, the blower body defining an air duct with an outwardly tapered air inlet and an air outlet opening, wherein the motor for driving a fan is received in the air duct. The <CIT> describes a venturi tube fan assembly for use in a blower device having an inlet bell mouth for concentrating the airflow, a motor with a tapering nose exceeding to the air inlet, a fan, and an outlet diffuser. The <CIT> describes an axial-flow garden blower having a duct part fixedly clamped between a blower body and a blow pipe, wherein a first duct part receiving a first level fan and the second duct part receiving a second level fan.

However, a shortcoming which the centrifugal blower and the axial-flow blower both have is that they generate a lot of noise when in use. Since blowers generally need to be held in the hand of the user, the distance between the source of noise and the user is very short; in the case of staff who frequently operate blowers, working for long periods of time in a high-noise environment easily causes discomfort, and in serious cases might affect the hearing.

The aim of the present application is to provide a blower that is capable of reducing noise generated when in use and increasing blowing efficiency.

To achieve the above objective, the present application provides an axial-flow blower as defined by claim <NUM>. The axial-flow blower, comprising: a blower body, having accommodated therein a fan and an electric motor driving the fan to rotate, a rotation shaft of the fan defining a longitudinal axis; a blow pipe, removably attached to the blower body; a tapered member is provided between the electric motor and an air inlet of the blower body, the tapered member gradually narrowing toward the air inlet.

The blower body has a protective cover, the air inlet being defined by the protective cover, and a near end of the tapered member being connected to the protective cover. An umbrella-like protrusion is formed on the near end of the tapered member, and an annular receiving part is formed on a central part of the protective cover, the annular receiving part consisting of multiple circumferentially spaced fan-shaped parts, and the umbrella-like protrusion being snap-fitted to the fan-shaped parts. Optionally, at least one opening is formed in a peripheral wall of the tapered member, for the purpose of leading a portion of an airflow into the interior of the tapered member.

In a preferred embodiment, a groove is formed on a peripheral wall of the tapered member, the groove allowing a cable to pass through. The groove may be defined by a protruding part extending outward from the peripheral wall of the tapered member.

In a preferred embodiment, the blower body comprises an air-intake-side casing and an air-output-side casing, the air-intake-side casing comprising an electric motor support, and a far end of the tapered member being connected to the electric motor support. The electric motor support has an upstream-side opening and a downstream-side opening, which are in communication with a first opening and a second opening in an electric motor casing respectively. The upstream-side opening comprises at least one notch formed in a near-end outer wall of the electric motor support, preferably multiple notches separated by finger-like parts.

In a preferred embodiment, a far end of the electric motor support comprises an inner ring, an outer ring, and fastener mounting holes located between the inner ring and the outer ring, the downstream-side opening being formed between the inner ring and the outer ring and being located between adjacent fastener mounting holes. The electric motor support is securely connected to an inner wall of the air-intake-side casing by means of a support member, a near-end edge of the support member being inclined relative to the longitudinal axis; a junction of the near-end edge and the electric motor support is located at a far side of a vertical plane passing through the center of each notch, and a junction of the near-end edge and the inner wall of the air-intake-side casing is located at a near side of the vertical plane.

In a preferred embodiment, a near end of the air-intake-side casing opens radially outward, and the ratio d4/d5 of a minimum distance d4 to a maximum distance d5 in a vertical direction between an inner wall of the air-intake-side casing and an outer wall of the tapered member is <NUM> - <NUM>. The ratio d6/d7 of a maximum outer diameter d6 of the tapered member to a minimum inner diameter d7 of the air-intake-side casing is <NUM> - <NUM>.

In a preferred embodiment, the air-output-side casing comprises a tapered flow-guiding body that narrows gradually toward a far side. The ratio d4/d10 of a minimum distance d4 in a vertical direction between an inner wall of the air-intake-side casing and an outer wall of the tapered member to a minimum distance d10 in the vertical direction between an inner wall of the air-output-side casing and an outer wall of the tapered flow-guiding body is <NUM> - <NUM>.

In a preferred embodiment, the air-output-side casing further comprises an air output grille arranged at a far end of the air-output-side casing; an extremity of the tapered flow-guiding body enters the air output grille but does not extend out of a far-end face of the air output grille. The air output grille comprises at least two concentric rings, with adjacent concentric rings being connected to each other by means of radially extending support ribs. For two radially adjacent concentric rings, the ratio of the axial width of the concentric ring located at the inside in a radial direction to the axial width of the concentric ring located at the outside in a radial direction is <NUM> - <NUM>.

In a preferred embodiment, the fan is located in the air-intake-side casing, and is located downstream of the electric motor. The fan is connected to an output shaft of the electric motor by means of a connection member, the connection member comprising a central hole and multiple arc-shaped protruding parts that protrude from a periphery; the central hole receives the output shaft, and the arc-shaped protruding parts are inserted into arc-shaped slots formed in a central hub of the fan. The ratio d8/d9 of a longitudinal distance d8 between the electric motor support and the fan to a longitudinal length d9 of the electric motor support is <NUM> - <NUM>.

In a preferred embodiment, at least a part of the air-intake-side casing and at least a part of the air-output-side casing are exposed to the environment.

In a preferred embodiment, the blower body further comprises a handle and a battery pack installation mechanism, the battery pack installation mechanism being positioned between the air-intake-side casing and a gripping part of the handle.

<FIG> shows a blower <NUM> according to an embodiment of the present application; the blower is an axial-flow blower, and comprises a blower body <NUM> and a blow pipe <NUM> mounted on the blower body <NUM>. A fan, and an electric motor driving the fan to rotate, are accommodated in the blower body <NUM>. In a state of not being used, a user can remove the blow pipe <NUM> from the blower body <NUM> to reduce storage space.

To facilitate description, in this text, a straight line on which a rotation shaft of the fan in the blower <NUM> lies is defined as a longitudinal axis, a side facing toward an air outlet of the blow pipe <NUM> is called a far side or downstream side, and a side facing toward an air inlet of the blower body <NUM> is called a near side or upstream side.

<FIG> shows an airflow generation assembly <NUM> in the blower body <NUM>; the airflow generation assembly defines an air flow path in the blower body <NUM>. From the near side to the far side, the airflow generation assembly <NUM> sequentially comprises a protective cover <NUM>, an air-intake-side casing <NUM> and an air-output-side casing <NUM>. In this embodiment, a dismantlable connection between the blower body <NUM> and the blow pipe <NUM> is achieved by means of mating between an L-shaped locking member <NUM> on the blow pipe <NUM> and a locking protrusion <NUM> on the air-output-side casing <NUM>.

<FIG> shows the blow pipe <NUM>, with the L-shaped locking member <NUM> being arranged on a near end thereof; the L-shaped locking member <NUM> defines an axially extending slot <NUM> and a circumferentially extending slot <NUM>. When performing assembly, the blow pipe <NUM> is fitted over the air-output-side casing <NUM>, aligning the locking protrusion <NUM> with the axially extending slot <NUM> of the L-shaped locking member. The locking protrusion <NUM> is then pushed into the axially extending slot <NUM> until the locking protrusion <NUM> reaches an extremity of the axially extending slot <NUM>. Finally, the blow pipe <NUM> is rotated relative to the air-output-side casing <NUM>, such that the locking protrusion <NUM> enters the circumferentially extending slot <NUM> of the L-shaped locking member, thereby achieving locking. Two or more L-shaped locking members <NUM> spaced apart in the circumferential direction may be provided on the blow pipe <NUM>; at the same time, a corresponding number of locking protrusions <NUM> are formed in corresponding positions on the air-output-side casing <NUM>. Although this embodiment uses an L-shaped locking member, other forms of dismantlable connection are also feasible, e.g. a snap-fit connection.

<FIG> is a side view of the blow pipe <NUM>. The blow pipe <NUM> may be divided along the longitudinal axis into a far-side part <NUM> and a near-side part <NUM>, with a step <NUM> being formed at the boundary of the two parts. When assembly is complete, the step <NUM> of the blow pipe <NUM> abuts a far-end edge of the air-output-side casing <NUM>. In an embodiment that is not shown, no step is present between the far-side part and near-side part of the blow pipe <NUM>; the blow pipe <NUM> extends smoothly in the longitudinal axial direction.

Viewed from one side, a plane P1 in which a far-end edge of the far-side part <NUM> of the blow pipe lies is inclined by an angle a relative to a vertical plane P2 perpendicular to the longitudinal axis, so that an upper side of the blow pipe <NUM> extends a greater distance relative to a lower side. The angle a is preferably less than <NUM> degrees, more preferably less than <NUM> degrees, and especially preferably less than <NUM> degrees. In general, when the user is holding the blower by hand to perform a job, the angle a readily concentrates the force of the airflow into a target region. Similarly viewed from one side, a straight line on which an outer surface <NUM> of the blow pipe lies is at an angle relative to the longitudinal axis; this is referred to as the taper angle of the blow pipe, and is preferably less than <NUM> degrees, more preferably less than <NUM> degrees, and especially preferably less than <NUM> degrees. Too large a taper angle results in a significant decrease in the area of an air delivery port, and this will increase the force of the airflow at the air delivery port excessively, possibly blowing up heavy objects undesirably, and will also exert high pressure on a blow pipe inner wall close to the air delivery port. Optionally, a bottom support member is provided at the near-side part <NUM> of the blow pipe <NUM>, allowing the blower to be placed stably on the ground, and preventing wear to a blow pipe outer surface.

The airflow generation assembly <NUM> is described below in conjunction with <FIG>. <FIG> is an exploded drawing of the airflow generation assembly <NUM>, showing the air-intake-side casing <NUM>, the air-output-side casing <NUM> and an air output grille <NUM>. In this embodiment, a near-end diameter of the air-output-side casing <NUM> is slightly less than a far-end diameter of the air-intake-side casing <NUM>, such that a near end of the air-output-side casing <NUM> can be inserted into a far end <NUM> of the air-intake-side casing <NUM>. <FIG> shows the air-intake-side casing <NUM>, with two pairs of fastener supports <NUM>, <NUM> being formed on an outer wall of the far end <NUM> thereof; a gap <NUM> is present between a first pair of fastener supports <NUM>, and a gap <NUM> is present between a second pair of fastener supports <NUM>. <FIG> shows the air-output-side casing <NUM>, with fastener supports <NUM>, <NUM> being formed on an outer wall of the near end thereof. Once the air-output-side casing <NUM> has been inserted into the air-intake-side casing <NUM>, the fastener supports <NUM>, <NUM> on the air-output-side casing <NUM> enter the gaps <NUM>, <NUM> respectively, and fasteners (e.g. screws or pins) are passed through the aligned fastener supports <NUM>, <NUM> and <NUM>, <NUM> to securely connect the two casings <NUM>, <NUM>. Such a manner of installation prevents the airflow from flowing out of an airflow passage through a gap at the junction of the air-intake-side casing <NUM> and air-output-side casing <NUM>. Preferably, a positioning member <NUM>, <NUM> is provided on an outer wall of the air-intake-side casing <NUM> and/or the air-output-side casing <NUM>; the positioning member is matched to a corresponding feature in a body housing, to ensure that the casings <NUM>, <NUM> are installed at predetermined positions in the blower body <NUM>. In addition, the air-output-side casing <NUM> and/or air-intake-side casing <NUM> may have a bottom support member <NUM>; when the blower is placed on the ground, the bottom support member <NUM> prevents the casing outer wall from coming into contact with the ground. A near end <NUM> of the air-intake-side casing <NUM> is opened radially outward, substantially in a trumpet shape. The protective cover <NUM> is removably connected to the near end <NUM> of the air-intake-side casing <NUM>.

Preferably, at least a part of the air-intake-side casing <NUM> and at least a part of the air-output-side casing <NUM> are exposed to the environment. As shown in <FIG>, in this embodiment, the body housing of the blower body <NUM> only encloses a near-side part of the air-intake-side casing <NUM>; it does not completely enclose the casings <NUM>, <NUM>. This design reduces the housing weight and the manufacturing cost. Furthermore, since contact between the body housing and the casings <NUM>, <NUM> is reduced, even if the casings <NUM>, <NUM> vibrate during operation, collisions and rubbing between the body housing and the casings <NUM>, <NUM> are limited, thus reducing noise when the blower is running.

<FIG> show the internal structure of the air-intake-side casing <NUM>, comprising an electric motor support <NUM>, in which the electric motor is accommodated. The electric motor support <NUM> is securely connected to an inner wall of the air-intake-side casing <NUM> by means of multiple support members <NUM>. In this embodiment, the support member <NUM> is constructed in the form of a blade, with the thickness of a near-end edge <NUM> thereof being greater than the thickness of a far-end edge <NUM>. A near end <NUM> of the electric motor support <NUM> is open, for the purpose of receiving the electric motor. A far end <NUM> of the electric motor support <NUM> comprises an inner ring <NUM>, an outer ring <NUM>, and fastener mounting holes <NUM> located between the inner ring and the outer ring. An output shaft <NUM> of an electric motor <NUM> (shown in <FIG>) extends through a central hole <NUM> defined by the inner ring <NUM>. Fasteners (e.g. screws) pass through the fastener mounting holes <NUM> to secure the electric motor <NUM> to the electric motor support <NUM>.

Openings allowing the airflow to pass through the electric motor support are provided at a downstream side and an upstream side of the electric motor support <NUM>. In this embodiment, an upstream-side opening of the electric motor support <NUM> is formed as a notch <NUM> in a near-end outer wall of the support; the notch <NUM> is aligned with a first opening <NUM> in an electric motor casing (shown in <FIG>). Preferably, adjacent notches <NUM> are separated by finger-like parts <NUM>. A downstream-side opening <NUM> of the electric motor support is formed between the inner ring <NUM> and outer ring <NUM> and located between adjacent fastener mounting holes <NUM>; the downstream-side opening <NUM> is aligned with a second opening <NUM> in the electric motor casing (shown in <FIG>).

<FIG> shows the internal structure of the air-output-side casing <NUM>. The air-output-side casing <NUM> comprises a tapered flow-guiding body <NUM> which narrows gradually toward the far side. The air-output-side casing <NUM> has multiple static blades <NUM>, which extend from an outer wall of the tapered flow-guiding body <NUM> to an inner wall of the air-output-side casing <NUM>. The static blades <NUM> are located at a near end of the air-output-side casing <NUM>, and arranged close to the fan. Preferably, the number of static blades <NUM> is greater than or equal to the number of fan blades. In this embodiment, a peripheral wall of the tapered flow-guiding body <NUM> is closed, with no opening being provided in the peripheral wall; an accelerated airflow generated by the rotation of the fan will not flow back into the tapered flow-guiding body <NUM>. Although the static blade <NUM> shown in <FIG> has a smooth edge <NUM>, the static blade may also be designed to have a non-smooth edge, e.g. a corrugated or serrated edge.

<FIG> shows the air output grille <NUM>, which is arranged at a far end of the air-output-side casing <NUM>. In this embodiment, the air output grille <NUM> is removably mounted on an inner wall at the far end of the air-output-side casing <NUM> by means of a snap-fit connection member <NUM>. The air output grille <NUM> could also be attached to the air-output-side casing <NUM> in another way, or could be integrally formed with the air-output-side casing <NUM>. The air output grille <NUM> comprises at least two concentric rings <NUM>, <NUM>, <NUM>, with adjacent concentric rings being connected to each other by means of radially extending support ribs <NUM>, <NUM>.

<FIG> shows a cross section of the air output grille <NUM>. The three concentric rings <NUM>, <NUM>, <NUM> have axial widths d1, d2, d3 respectively. Preferably, the axial width of the concentric ring located at the inside in a radial direction is less than the axial width of the concentric ring located at the outside in a radial direction. The ratios d1/d2 and d2/d3 of the axial widths of adjacent concentric rings are preferably <NUM> - <NUM>, more preferably <NUM> - <NUM>, and especially preferably <NUM> - <NUM>. The shape of the support ribs <NUM>, <NUM> connecting adjacent concentric rings <NUM>, <NUM>, <NUM> may be trapezoidal. The number of concentric rings and support ribs in the air output grille may be determined according to parameters such as the power of the blower, the cross-sectional area of the airflow passage and the length of the blow pipe. The number of concentric rings and support ribs should not be too large, because a densely arranged grille will undesirably reduce the actual air output area. The air output grille <NUM> shown in <FIG> has three concentric rings, with adjacent concentric rings being connected to each other by four support ribs.

<FIG> shows a tapered member <NUM>, which is arranged between the electric motor and an air inlet of the body housing, and narrows gradually toward the air inlet. In this embodiment, a far end <NUM> of the tapered member <NUM> is connected to the near end <NUM> of the electric motor support <NUM> of the air-intake-side casing <NUM>, and a far-end edge <NUM> of the tapered member <NUM> closes the notch <NUM> formed in the near-end outer wall of the support, defining an opening allowing an airflow to enter the electric motor. Optionally, at least one opening <NUM> is formed in a peripheral wall of the tapered member, for the purpose of leading a portion of an incoming airflow directly into the interior of the tapered member <NUM>. In order to reduce noise, it is also possible to remove the opening <NUM> in the tapered member <NUM>, and rely on the notch <NUM> alone to lead the airflow into the electric motor.

A groove <NUM> is also formed on the peripheral wall of the tapered member <NUM>, for the purpose of guiding a cable <NUM> associated with operation of the electric motor or fan (shown in <FIG>). In this embodiment, the groove <NUM> is formed by a protruding part <NUM> that extends outward from the peripheral wall of the tapered member <NUM>; the protruding part <NUM> is aligned with an opening <NUM> (shown in <FIG>) formed in the air-intake-side casing <NUM>.

<FIG> shows the protective cover <NUM>. Based on safety considerations, and at the same time in order to prevent small objects from entering the blower body <NUM> with the airflow, the protective cover <NUM> is constructed as a grille. A near end <NUM> of the tapered member <NUM> is removably connected to the protective cover <NUM>. A first mating part is formed on the near end <NUM> of the tapered member, and a second mating part is formed on a central part <NUM> of the protective cover <NUM>. According to the present invention, the first mating part is an umbrella-like protrusion <NUM>, and the second mating part is an annular receiving part consisting of multiple circumferentially spaced fan-shaped parts <NUM>; the umbrella-like protrusion <NUM> is snap-fitted to the fan-shaped parts <NUM>.

<FIG> shows a cross section of the airflow generation assembly <NUM>. The near-end edge <NUM> of the support member <NUM> of the electric motor support <NUM> is inclined relative to the longitudinal axis. If a vertical plane passing through the centers of all of the notches <NUM> is defined as a plane P3, then a junction <NUM> of the near-end edge <NUM> and the electric motor support <NUM> is located at the far side of the plane P3, and a junction <NUM> of the near-end edge <NUM> and the inner wall of the air-intake-side casing <NUM> is located at the near side of the plane P3.

Since the tapered member <NUM> narrows gradually toward an air inlet of the blower, it occupies a small cross section in a region close to the air inlet, and thus will not significantly reduce the air intake area. At the same time, in the present application, the near end <NUM> of the air-intake-side casing <NUM> is designed to open outward radially, and this increases the air intake area. Since the tapered member <NUM> gradually expands toward the far side and the air-intake-side casing <NUM> narrows toward the far side, the cross-sectional area of an annular airflow passage located between the two parts decreases in the airflow direction, and the flow speed of the airflow is thereby increased. The ratio d4/d5 of a minimum distance d4 to a maximum distance d5 in the vertical direction between the inner wall of the air-intake-side casing and an outer wall of the tapered member is preferably <NUM> - <NUM>, more preferably <NUM> - <NUM>, and especially preferably <NUM> - <NUM>. The ratio d6/d7 of a maximum outer diameter d6 of the tapered member <NUM> to a minimum inner diameter d7 of the air-intake-side casing <NUM> is preferably <NUM> - <NUM>, more preferably <NUM> - <NUM>, and especially preferably <NUM> - <NUM>. The tapered member <NUM> is arranged at the air inlet, and is connected to the protective cover <NUM>, thus, the cross section of the airflow passage starts to gradually change from the air inlet, and will not suddenly decrease due to the electric motor appearing in the airflow passage. This helps to form a steady airflow in the blower body <NUM>, increasing the blower efficiency.

The tapered flow-guiding body <NUM> extends from an upstream end of the air-output-side casing <NUM> to a downstream end. In this embodiment, the tapered flow-guiding body <NUM> extends into the air output grille <NUM>, but does not extend out of a far-end face of the air output grille <NUM>. Preferably, an extremity <NUM> of the tapered flow-guiding body and the far-end face of the air output grille <NUM> are located in the same vertical plane P4. The concentric rings of the air output grille <NUM> divide an air outlet of the blower body <NUM> into multiple annular regions, such that a high-speed airflow guided by the tapered flow-guiding body <NUM> flows into the blow pipe <NUM> smoothly.

In <FIG>, arrows are used to show a cooling airflow that dissipates heat from the electric motor. Air entering through the protective cover <NUM> passes through the annular airflow passage between the air-intake-side casing <NUM> and the tapered member <NUM>. A main airflow flows forward along the airflow passage and enters the air-output-side casing <NUM>; a portion of air enters the electric motor via the upstream-side opening of the electric motor support <NUM> and the first opening in the electric motor casing, carries away heat generated during electric motor operation, and then leaves the electric motor via the second opening in the electric motor casing and the downstream-side opening of the electric motor support <NUM>. The cooling airflow flows radially outward through a space between the electric motor support <NUM> and a fan <NUM>, and then enters the air-output-side casing <NUM> with the main airflow.

<FIG> shows a longitudinal distance d8 between the electric motor support <NUM> and the fan <NUM>, and a longitudinal length d9 of the electric motor support <NUM>; the ratio d8/d9 between the two is preferably <NUM> - <NUM>, more preferably <NUM> - <NUM>, and especially preferably <NUM> - <NUM>. This ratio can ensure that the cooling airflow will not build up in the electric motor, and will not affect the progress of the main airflow. The ratio d4/d10 of a minimum distance d4 in the vertical direction between the inner wall of the air-intake-side casing <NUM> and the outer wall of the tapered member <NUM> to a minimum distance d10 in the vertical direction between an inner wall of the air-output-side casing <NUM> and the outer wall of the tapered flow-guiding body <NUM> is preferably <NUM> - <NUM>, more preferably <NUM> - <NUM>, and especially preferably <NUM> - <NUM>. This ratio can avoid undesired obstruction of the airflow when entering the air-output-side casing <NUM> from the air-intake-side casing <NUM>.

<FIG> shows the fan <NUM> and the electric motor <NUM>, both being located in the air-intake-side casing <NUM>, wherein the electric motor <NUM> is installed in the electric motor support <NUM>. The first opening <NUM> and second opening <NUM> are formed at two sides of the electric motor casing respectively, as an inlet and outlet for the cooling airflow. The fan <NUM> is connected to an output shaft <NUM> of the electric motor <NUM> by means of a connection member <NUM>. In this embodiment, the connection member <NUM> comprises a central hole <NUM> and multiple arc-shaped protruding parts <NUM> that protrude from a periphery. The central hole <NUM> is configured to receive the output shaft <NUM>; the arc-shaped protruding parts <NUM> are inserted into arc-shaped slots <NUM> formed in a central hub <NUM> of the fan <NUM>. The connection member <NUM> may be made of a non-elastic material, such as metal.

The electric motor <NUM> may be a brushless motor, and the diameter thereof is preferably <NUM> - <NUM>, more preferably <NUM> - <NUM>, and especially preferably <NUM> - <NUM>. The outer diameter of the fan is preferably <NUM> - <NUM>, more preferably <NUM> - <NUM>, and especially preferably <NUM> - <NUM>. A gap between a fan blade extremity <NUM> and the inner wall of the air-intake-side casing <NUM> is preferably <NUM> - <NUM>, and more preferably <NUM> - <NUM>. Too small a gap might result in the blade scraping the casing inner wall; too large a gap would increase noise, and reduce blowing efficiency.

Returning to <FIG>, the blower body <NUM> further comprises a handle <NUM>; the handle <NUM> has a gripping part <NUM> for a user to grip, and a connecting part <NUM> that connects the gripping part <NUM> to the body housing. Control buttons <NUM>, <NUM> are provided on the gripping part <NUM>, and the user can operate the blower with a single hand. Optionally, the connecting part <NUM> is connected to the body housing in such a way as to be able to rotate around a pivot <NUM>, allowing the user to adjust the orientation of the handle <NUM> relative to the body housing. After completing adjustment, the user can use a locking mechanism to lock the orientation of the handle.

Claim 1:
An axial-flow blower (<NUM>), comprising:
a blower body (<NUM>), having accommodated therein a fan (<NUM>) and an electric motor (<NUM>) driving the fan (<NUM>) to rotate, a rotation shaft of the fan (<NUM>) defining a longitudinal axis, wherein the blower body (<NUM>) has a protective cover (<NUM>), the protective cover (<NUM>) defining an air inlet of the blower body (<NUM>);
a blow pipe (<NUM>), removably attached to the blower body (<NUM>), wherein a side of the blower body (<NUM>) facing toward an air outlet of the blow pipe (<NUM>) is called a downstream side, and a side facing toward the air inlet of the blower body (<NUM>) is called an upstream side; and
a tapered member (<NUM>) is provided between the electric motor (<NUM>) and the air inlet of the blower body (<NUM>);
wherein the tapered member (<NUM>) gradually narrows toward the air inlet and an upstream end (<NUM>) of the tapered member (<NUM>) is connected to the protective cover (<NUM>),
characterized in that an umbrella-like protrusion (<NUM>) is formed on the upstream end (<NUM>) of the tapered member (<NUM>), and an annular receiving part is formed on a central part of the protective cover (<NUM>), the annular receiving part consisting of multiple circumferentially spaced fan-shaped parts (<NUM>), and the umbrella-like protrusion (<NUM>) being snap-fitted to the fan-shaped parts (<NUM>).