CN218093583U - Impeller, fan and dust catcher - Google Patents

Abstract

The utility model relates to the field of fluid machinery, and discloses an impeller, a fan and a dust collector, which comprises a hub and a plurality of blades, wherein the blades are arranged on the circumference of the hub; the blades comprise pressure surfaces, the pressure surfaces are the surfaces of the blades facing the rotating direction of the impeller, the pressure surfaces of the front sections of the blades are concave inwards, and the concave direction is opposite to the rotating direction of the impeller. The pressure surface through with the blade anterior segment sets up to the indent, and the direction of indent is opposite with the direction of rotation of impeller, is favorable to laminating fluid drainage to the pressure surface of blade anterior segment can form the parcel in inlet department to the fluid, can reduce the loss of revealing of fluid in inlet department, enlarges the pressure surface of impeller under the low discharge, increases the area of contact of pressure surface and fluid, promotes the impeller performance.

Description

Impeller, fan and dust catcher

Technical Field

The utility model relates to the field of fluid machinery, especially, relate to an impeller, fan and dust catcher.

Background

The fan of the dust collector drives the impeller to rotate at high speed through the motor, a high negative pressure space is formed in the sealed cavity, and external dust is sucked into the dust collecting device, so that the cleaning purpose is achieved.

At present, the rotating speed of a fan of the dust collector is not equal to 20000-150000rpm, and the whole fan can realize 120-230AW pneumatic power. The impeller is used as a key part of the fan of the dust collector, and the performance of the impeller directly determines the pneumatic power and efficiency of the whole fan. However, the aerodynamic performance of current impellers is poor.

SUMMERY OF THE UTILITY MODEL

The embodiment of the utility model provides an aim at providing an impeller, fan and dust catcher, the pneumatic performance of this impeller is more excellent.

The embodiment of the utility model provides a solve its technical problem and adopt following technical scheme: providing an impeller comprising a hub and a plurality of blades arranged circumferentially of the hub; the blades comprise pressure surfaces, the pressure surfaces are the surfaces, facing the rotation direction of the impeller, of the blades, the pressure surfaces of the front sections of the blades are concave, and the concave direction is opposite to the rotation direction of the impeller.

In some embodiments, the pressure surfaces of the vane tail sections are convex in the same direction as the direction of rotation of the impeller.

In some embodiments, the blade height decreases gradually in a direction from the blade leading section to the blade trailing section.

In some embodiments, the curvature of the blade front section curve is less than the curvature of the blade rear section curve.

In some embodiments, the blade has a rounded smooth transition at the junction of the blade tip face and the trailing edge face.

In some embodiments, the surface at the trailing end periphery of the hub extends at an angle of 0 ° to 50 ° to the axial direction of the hub.

In some embodiments, the blade tail section comprises 5% to 30% of the total length of the blade.

In some embodiments, the blade leading section and the blade trailing section are smoothly transitioned.

The embodiment of the utility model provides a solve its technical problem and still adopt following technical scheme: there is provided a fan comprising an impeller as described above.

The embodiment of the utility model provides a solve its technical problem and still adopt following technical scheme: a vacuum cleaner comprises the fan.

Compared with the prior art, the embodiment of the utility model provides an among impeller, fan and the dust catcher, set up to the indent through the pressure surface with the blade anterior segment, the direction of indent is opposite with the direction of rotation of impeller, is favorable to laminating fluid drainage to the pressure surface of blade anterior segment can form the parcel to the air inlet department, can reduce the loss of revealing of fluid in air inlet department, enlarges the pressure surface of impeller under the low discharge, increases the area of contact of pressure surface and fluid, promotes the impeller performance.

Drawings

One or more embodiments are illustrated by way of example in the accompanying drawings, which correspond to the figures in which like reference numerals refer to similar elements and which are not to scale unless otherwise specified.

FIG. 1 is a schematic view of the structure of a triangular grooved rib on a shark skin;

fig. 2 is a schematic structural diagram of an impeller provided in embodiment 1 of the present invention;

FIG. 3 is a schematic view of the impeller shown in FIG. 2 at another angle;

FIG. 4 is a schematic view of the turbine and impeller surfaces when grooves are not provided;

FIG. 5 is a schematic view of the turbine and impeller surfaces after the grooves are provided;

FIG. 6 is a schematic view of the groove structure of the impeller shown in FIG. 2;

fig. 7 is a schematic structural view of an impeller provided in embodiment 2 of the present invention;

fig. 8 is a schematic view of the impeller shown in fig. 7 at another angle.

Detailed Description

To facilitate understanding of the present invention, the present invention will be described in more detail with reference to the accompanying drawings and specific embodiments. It will be understood that when an element is referred to as being "connected" to another element, it can be directly on the other element or intervening elements may be present. The terms "upper", "lower", "left", "right", "upper", "lower", "top" and "bottom" used in the present specification indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

Shark is one of the fastest animals in ocean swim, and a large number of experiments and researches show that compared with other smooth structures, the shark skin (triangular groove rib) imitating structure has better characteristics of drag reduction and viscosity reduction. The scale shape on the surface of sharkskin is shown in figure 1.

The viscosity reduction and drag reduction of the imitation sharkskin (triangular groove rib) structure applies a vortex drag reduction theory, a plurality of vortexes can be generated in turbulence, the vortexes can generate energy loss when contacting with the surface of the structure, so that the resistance is increased, and secondary vortexes can be generated by the diffusion of the vortexes, so that the resistance is also increased. The groove structure arranged on the structure surface can lift the vortex, so that the vortex stays above the groove land, the speed gradient and the speed pulse of the part of the air flow in the groove are reduced to be lower than those of the part of the air flow on the structure surface, and the shearing stress of the air flow and the structure surface is reduced accordingly. Meanwhile, the groove structure can guide the vortex structure to move along the groove, so that the transverse migration of the vortex is avoided, and the bursting and the entanglement of the vortex and the turbulence outside the boundary layer are weakened.

The size of the grooves of the imitation shark skin (triangular groove rib) structure needs to be strictly limited. When the vortex structure is smaller than the groove, the vortex structure can fall into the groove to interact with the surface of the groove, when the size of the vortex is larger than that of the groove structure, the vortex is lifted, the contact area with the surface of the groove is reduced, the interaction is also reduced, and meanwhile, the surface area of the groove surface is larger than that of the plane, so that the drag reduction effect can be shown only when the width and the distance of the groove are small enough, and the friction resistance is avoided to be smaller than that of the smooth plane. The depth-to-width ratio of the groove, namely the ratio of the depth to the width of the groove is related to the depth and the width of the groove, the depth-to-width ratio is small, the width of the groove is large, and a vortex is easy to fall into the groove to interact with the surface of the groove; the depth-to-width ratio is large, the width of the groove is small, the vortex is not easy to fall into the groove, the contact with the surface of the groove is reduced, and the interaction is reduced. Therefore, the drag reduction effect can be exhibited only when the aspect ratio is appropriate and the wall surface frictional resistance is smaller than that of a smooth plane.

Example 1

Inspired above, the embodiment 1 of the utility model provides an impeller, this impeller can be semi-open impeller, also can be for the closed impeller. Generally, a shrouded impeller includes a disk, a shroud, and a plurality of blades, the disk and the shroud being disposed opposite to each other, the plurality of blades being disposed between the disk and the shroud. In contrast to a shrouded impeller, a semi-open impeller has no shroud. In the present embodiment, a description will be given taking a semi-open impeller as an example.

It is worth to be noted that the wheel cover of the closed impeller has large opening and low strength, which limits the improvement of the circumferential speed of the closed impeller and the improvement of the motor efficiency, while the semi-open impeller has no limitation of the end cover, so that the maximum allowable circumferential speed is obviously improved. Therefore, the semi-open impeller can realize higher rotating speed and higher pneumatic efficiency.

Referring to fig. 2 and 3, the impeller includes a hub 10 and a plurality of blades 20. The plurality of blades 20 are distributed at intervals along the circumferential direction of the hub 10, the plurality of blades 20 are arranged in a circumferential array, the hub 10 is arranged at the center of the circumferential array, and the distance between every two adjacent blades 20 is equal.

The hub 10 is generally conical or frusto-conical in shape. In the axial direction along wheel hub 10, wheel hub 10 can be divided into wheel hub 10 anterior segment, wheel hub 10 middle section and wheel hub 10 tail section, and wheel hub 10 middle section sets up between wheel hub 10 anterior segment and wheel hub 10 tail section. In the direction from the front section of the hub 10 to the rear section of the hub 12, the diameter of the hub 12 increases, i.e. the diameter of the front section of the hub 10 is smaller and the diameter of the rear section of the hub 10 is larger. Specifically, in the direction from the front section of the hub 10 to the rear section of the hub 10, the diameter of the hub 10 increases at first and then decreases, so that the surfaces of the front section and the middle section of the hub 10 are concave toward the direction close to the axis of the hub 10, and the surface of the rear section of the hub 10 is convex toward the direction away from the axis of the hub 10.

The surface at the trailing edge of the hub 10 extends in a direction that tends to be parallel to the axis of the hub 10, i.e., the edge of the trailing edge of the hub 10 at the end of the trailing section of the hub 10 that is distal from the leading section of the hub 10.

The trailing section of the hub 10 forms the disk of the semi-open impeller.

The impeller has an air inlet and an air outlet. The air inlet is close to the front section of the hub 10, and the air outlet is close to the rear section of the hub 10.

The blades 20 extend along a helix, which may have less than one turn. The centre lines of the helices along which the blades 20 extend all coincide with the axis of the hub 10, the helical direction of the helix along which each blade 20 extends being coincident.

The area between each adjacent two of the blades 20 forms a flow passage. One end of the flow passage is communicated with the air inlet of the impeller, and the other end of the flow passage is communicated with the air outlet of the impeller. During rotation of the impeller, fluid flows into the flow passage from the inlet port, flows along the flow passage in the flow passage, and then flows out of the flow passage from the outlet port. The direction of the flow channel from the air inlet to the air outlet is the development direction of the flow channel, and the width of the flow channel is increased along the development direction of the flow channel.

The number of the blades 20 is N, N is more than or equal to 7 and less than or equal to 11, and the specific number of the blades 20 can be determined according to the overall aerodynamic performance required by the impeller.

Each blade 20 includes a leading edge surface 21, a trailing edge surface 22, a blade top surface 23, a blade root surface 24, a pressure surface 25, and a suction surface 26. One surface of the blade 20 facing the rotation direction of the impeller is a pressure surface 25, one surface of the blade 20 away from the rotation direction of the impeller is a suction surface 26, and the peripheral edge of the blade 20 is formed with a leading edge surface 21, a trailing edge surface 22, a blade top surface 23, and a blade root surface 24. Specifically, the leading edge surface 21, the trailing edge surface 22, the blade top surface 23 and the blade root surface 24 are all located between the pressure surface 25 and the suction surface 26, the leading edge surface 21 is close to the air inlet of the impeller, the leading edge surface 21 forms an included angle with the axis of the hub 10, and one end of the leading edge surface 21 far away from the axis of the hub 10 is higher than one end of the leading edge surface 21 close to the axis of the hub 10, which is mainly arranged to reduce the airflow resistance at the leading edge of the blade during the rotation of the impeller. The trailing edge surface 22 is close to the air outlet of the impeller, and one end of the trailing edge surface 22 close to the axis of the hub 10 is higher than the other end of the trailing edge surface 22 far away from the axis of the hub 10. One end of the blade top surface 23 close to the air inlet is connected with one end of the leading edge surface 21, specifically, one end of the leading edge surface 21 far away from the axis of the hub 10; the end of the tip surface 23 near the air outlet is connected to the end of the trailing edge surface 22, specifically the end of the trailing edge surface 22 near the axis of the hub 10. The blade root surface 24 is attached to the surface of the hub 10 to form an integral structure, one end of the blade root surface 24 close to the air inlet is connected with one end of the leading edge surface 21, specifically, one end of the leading edge surface 21 close to the axis of the hub 10, one end of the blade root surface 24 close to the air outlet is connected with one end of the trailing edge surface 22, specifically, one end of the trailing edge surface 22 close to the tail end periphery of the hub 10.

The extending direction of the surface of the hub 10 close to the trailing edge surface 22 of the blade 20, that is, the extending direction of the surface at the trailing edge periphery of the hub 10 and the axial direction of the hub 10, is 0-50 °, so that the trailing edge periphery of the hub 10 has a guiding function, and the included angle between the fluid guiding function and the axial direction of the hub 10 is 0-50 °, so as to reduce the energy loss caused by the collision of the fluid and the inner wall of the casing of the fan, the joint of the blade top surface 23 of the blade 10 and the trailing edge surface 22 is in a round-corner smooth transition, and the fluid flowing through the blade 10 to do work can be better guided to the axial direction substantially parallel to the hub 10, so as to reduce the collision loss of the fluid at the outlet of the trailing edge surface 22 of the blade 20 and the inner wall of the casing of the fan, and improve the performance of the impeller. The air flow enters the impeller axially and leaves the impeller axially, which can be applied to the fan of a vacuum cleaner.

In the extending direction of the blade 20, that is, in the direction along the spiral line, the blade 20 may be divided into a front section of the blade 20 and a rear section of the blade 20. Wherein, the front section of the blade 20 is close to the air inlet of the impeller, and the tail section of the blade 20 is close to the air outlet of the impeller. The pressure surface 25 of the leading section of the blade 20 is concave to form a concave surface, specifically, the concave direction is opposite to the rotation direction of the impeller. The pressure surface 25 of the trailing section of the vane 20 is convex, forming an outer convex surface, in particular, convex in the same direction as the direction of rotation of the impeller. The front section of the blade 20 and the tail section of the blade 20 are smoothly transited.

After the impeller is installed, a gap inevitably exists between the impeller and the inner wall of the shell of the fan, when the impeller rotates, a pressure difference is generated between the flow channel and the gap, partial airflow in the flow channel leaks to the gap side through the blade top surface 23 of the blade, that is, leakage loss occurs when the fluid flows through the blade top surface 23 of the blade 20, and the performance of the impeller is reduced. In addition, when revealing present blade anterior segment even air inlet department, the fluid flow of effective work reduces, the pressure reduction that the fluid produced through the blade, cause impeller performance to reduce easily, consequently, should reveal more obviously to the influence of impeller performance when present blade 20 anterior segment, set up the direction indent opposite with the direction of rotation of impeller through the pressure surface 25 of blade 20 anterior segment, be favorable to laminating fluid drainage, and the pressure surface of blade 20 anterior segment can form the parcel to the fluid at air inlet department, can reduce the loss of revealing of fluid at air inlet department, enlarge the pressure surface of impeller under the low discharge, increase pressure surface and fluidic area of contact, promote impeller performance.

The pressure surface 25 under a small flow rate is described in detail here, and in the impeller under a small flow rate condition, the fluid cannot fill the whole flow channel, and a boundary layer separation phenomenon, that is, flow separation, may occur at the pressure surface 25 of the blade 20, and by arranging the pressure surface 25 of the blade 20 to be concave first and then convex, the fluid can be guided to be close to the surface of the hub 10, and to be close to the pressure surface 25 and the suction surface 26 of the blade 20, and the flow loss of the fluid near the blade top surface 23 is reduced.

The curvature of the front section of the blade 20 is less than the curvature of the rear section of the blade 20.

Referring to fig. 2, four points M, Q, N, and P are taken on the blade 20, where M and Q are two points on the blade 20 near the root surface 24, N and P are two points on the blade 20 near the tip surface 23, respectively, the MN connection line is located at the front section of the blade 20, and the PQ connection line is located at the tail section of the blade 20. Each of the portions of the front section of the blade 20 has the following features: the projection of the line MN on the pressure surface 25 or suction surface 26 of the blade 20 is approximately an arc, the direction of projection being opposite to the direction of rotation of the impeller. Each part of the tail section of the blade 20 has the following characteristics: the projection of the PQ connecting line on the pressure surface 25 or the suction surface 26 of the blade 20 is approximately an arc line or a straight line, the curvature of the projection is far larger than that of the projection of the MN connecting line on the pressure surface 25 or the suction surface 26 of the blade 20, the projection of the PQ connecting line on the tail section of the blade 20 close to the tail edge surface 22 is approximately a straight line, the projection of the PQ connecting line on the tail section of the blade 20 far away from the tail edge surface 22 is approximately an arc line, and the projection direction of the PQ connecting line on the pressure surface 25 or the suction surface 26 of the blade 20 is the same as the rotation direction of the impeller.

The blade height decreases in the direction from the front section of the blade 20 to the rear section of the blade 20, i.e. the direction in which the blade tip surface 23 points in the direction of the blade root surface 24. The blade height of 20 anterior segments of blade is great, does benefit to the fluid of parcel air inlet department, reduces fluidic leakage loss, and the blade height of 20 tail sections of blade is less, does benefit to the collision loss that alleviates the fluid of blade 20 and air outlet department, promotes the aerodynamic performance of impeller.

Because the blade height of the blade is gradually reduced in the direction from the front section of the blade 20 to the tail section of the blade 20, the power-applying capacity of the blade 20 is reduced, and the tail section of the blade 20 is provided with the convex surface to reduce the resistance loss, the simulation experiment verifies that when the tail section of the blade 20 accounts for 5% -30% of the total length of the blade 20, the effect of reducing the resistance loss of the tail section of the blade 20 is better, so that the overall performance of the impeller is better.

Grooves 30 are provided on the surface of the impeller. The grooves 30 run in the same direction as the flow path. Since the blades 20 extend along a helix, the flow passages also extend substantially along the helix. The development direction of the flow channel is along the extension direction of the flow channel and is from one end of the flow channel close to the air inlet to one end of the flow channel close to the air outlet. During the rotation of the impeller, vortices v are generated in the turbulent flow, and the contact of the vortices v with the surface of the impeller causes energy loss, as shown in fig. 4. The grooves 30 are formed in the surface of the impeller, the direction of the grooves 30 is consistent with the development direction of the flow channel, the functions of guiding flow and smoothing the flow direction can be achieved on fluid movement, air can move more smoothly, and the performance of the impeller is improved. In addition, the groove 30 can lift the vortex v above the land of the groove 30, as shown in fig. 5, the contact area of the vortex v and the surface of the impeller is reduced, the energy loss caused by the contact of the vortex v and the surface of the impeller is reduced, the vortex v can move along the groove 30 after being lifted, the land of the groove 30 can limit the movement direction of the vortex v, the energy loss caused by the transverse diffusion and development of the vortex v is effectively avoided, the fluid flow resistance is reduced, and the impeller performance is improved. In addition, the grooves 30 are formed in the surface of the impeller, the overall size of the impeller does not need to be changed, the impeller can be designed and machined on the existing impeller structure, and design cost is saved. In addition, the grooves 30 are formed in the surface of the impeller, so that partial materials of the impeller are removed, the weight of the impeller is reduced, the load of a load motor can be reduced, and the rotating speed of the impeller is indirectly improved.

The grooves 30 open on the surface of the hub 10 and extend from the front section of the hub 10 to the rear section of the hub 10, alternatively, the grooves 30 may extend from the front section of the hub 10 to the middle section of the hub 10. After the fluid enters the flow channel, the flow velocity of the fluid is slow, the blades 20 rotate to apply work to the fluid, and the static pressure and the kinetic energy of the fluid are synchronously improved. When the fluid flows to the flow channel near the trailing edge of the blade 20, the flow velocity of the fluid is faster, and the pressurizing and increasing effects of the fluid by the grooves 30 are slightly reduced. Therefore, the grooves 30 provided on the front section of the hub 10 can start to function when the flow velocity of the fluid is slow, the drag reduction effect is good, the flow channel near the trailing edge of the blade 20 has a lower drag reduction requirement than the front section, and therefore, the grooves 30 may not be provided at the trailing section of the hub 10 according to actual needs.

It will be appreciated that the grooves 30 may also open onto the surface of the blade 20, depending on the actual requirements. For example, the grooves 30 open onto the pressure side 25 and/or the suction side 26 of the blade 20. Since the blade 20 is thin, the opening of the groove 30 on the surface of the blade 20 easily causes the strength of the blade 20 to be reduced, and the blade has a small operable space and a large processing difficulty. Therefore, compared to forming the grooves 30 on the surface of the blade 20, forming the grooves 30 on the surface of the hub 10 can avoid a decrease in strength of the blade 20, and has a large operable space and is easier to process.

The cross section of the groove 30 is triangular, a shark skin-imitated structure, namely a triangular groove rib structure, can be formed, and the groove has excellent resistance reducing and viscosity reducing characteristics.

Referring to fig. 6, the dimensions of the trench 30 need to be strictly defined. When the size of the vortex is smaller than the width of the groove 30, the vortex falls into the groove 30 to interact with the groove wall of the groove 30 and the surface of the hub 10, and when the size of the vortex is larger than the width of the groove 30, the vortex is lifted, the contact area with the surface of the impeller is reduced, the interaction is also reduced, so that the wall friction resistance is smaller than that of a smooth plane only when the width and the interval of the groove 30 are proper, and the surface of the impeller has the drag reduction effect. The depth-to-width ratio of the groove 30 is related to the depth and the width of the groove 30, the depth-to-width ratio is small, the width of the groove 30 is large, and a vortex is easy to fall into the groove 30 and interact with the groove wall of the groove 30; the aspect ratio is large and the width of the groove 30 is small, the vortex is not easily dropped into the groove 30, the contact with the impeller surface is reduced, and the interaction is reduced. Therefore, the drag reduction effect can be exhibited only when the aspect ratio of the grooves 30 is appropriate and the wall surface frictional resistance is smaller than that of the hub surface.

Through experimental tests, when the parameters of the groove 30 are as follows, the effect of the groove 30 in lifting the vortex structure is more remarkable:

the number n of the grooves 30 between two adjacent blades 20 is not less than 5 and not more than 12, and the best value is when the number n of the grooves 30 between two adjacent blades 20 is 6.

The central angle A of the bottoms of the two adjacent grooves 30 is not less than 4 degrees and not more than 10 degrees, and the central angle A of the bottoms of the two adjacent grooves 30 is best when the central angle A is 8.6 degrees. It should be noted that the central angle a of the bottoms of the two adjacent grooves 30 is an included angle formed by a connecting line between the bottoms of the two adjacent grooves 30 close to the impeller air outlet and the bottoms of the two adjacent grooves 30 close to the impeller air inlet, and the larger the distance between the two adjacent grooves 30 is, the larger the central angle a of the bottoms of the two adjacent grooves 30 is, the smaller the distance between the two adjacent grooves 20 is, and the smaller the central angle a of the bottoms of the two adjacent grooves 30 is.

The width L of the groove 30 is less than or equal to 0.08mm and less than or equal to 0.14mm.

The depth H = (1 to 1.5) L of the groove 30.

In some embodiments, the number N =7 of the blades 20, the number N =6 of the grooves 30 between two adjacent blades 20, the central angle a =8.6 ° of the groove bottoms of two adjacent grooves 30, the width L =0.14mm of the grooves 30, and the depth H =1.07l =0.15mm of the grooves 30.

The width L of the single groove 30 accounts for 2% -3% of the total circumference of the single runner outlet.

The total width of the grooves 30 in a single flow channel accounts for 15-30% of the total length of the circumference of the outlet of the single flow channel.

It should be noted that the total circumferential length S of the outlet of a single flow passage, i.e., the circumferential length of the circumferential edge of the hub trailing end in the single flow passage, is shown in fig. 3.

Example 2

On one hand, since the hub 10 is substantially conical or truncated cone-shaped, the diameter of the front section of the hub 10 is small, and on the other hand, the grooves 30 need to ensure a certain width to avoid that a triangular groove structure cannot be formed, only a small number of grooves 30 can be accommodated on the surface of the front section of the hub 10, resulting in a small number of grooves 30 on the whole hub 10. Based on this, on the basis of the impellers provided in the foregoing embodiments, embodiment 2 of the present invention provides an impeller which is basically the same as the impeller provided in embodiment 1, and the difference mainly lies in the structural difference of the groove 30, specifically as follows:

referring to fig. 7 and 8, the trench 30 is divided into a long trench 32 and a short trench 34. The long trenches 32 and the short trenches 34 are alternately arranged. The long grooves 32 extend from the front section of the hub 10 to the rear section of the hub 10, that is, the long grooves 32 extend from the front section to the rear section of the flow channel. The short grooves 34 extend from the middle section of the hub 10 to the end section of the hub 10, i.e., the short grooves 34 extend from the middle section to the end section of the runner. Because the hub 10 is roughly in a cone or a truncated cone shape, the diameter of the rear section of the hub 10 is larger, in the development direction along the flow channel, the flow channel is gradually widened, the distance between the grooves 30 close to the air outlet of the impeller is gradually increased, so that the distance between the grooves 30 at the front section of the hub 10 is smaller, the effect of lifting the vortex by the grooves 30 at the front section of the hub 10 is better, the vortex is not easy to fall into the grooves 30 at the front section of the hub 10, the resistance reducing performance at the front section of the hub 10 is better, the distance between the grooves 30 at the middle section of the hub 10 and the rear section of the hub 10 is larger, the effect of lifting the vortex by the grooves 30 at the middle section and the rear section of the hub 10 is poorer, the vortex is easy to fall into the grooves 30 at the middle section and the rear section of the hub 10, and the resistance reducing performance at the middle section and the rear section of the hub 10 is poorer. Through setting up slot 30 into long slot 32 and short slot 34, short slot 34 can make full use of the space on the surface of wheel hub 10 tail section, and the quantity of long slot 32 equals with the quantity of slot 30 before improving basically, therefore, the slot 30 interval of wheel hub 10 front section department is unchangeable basically, the drag reduction performance of wheel hub 10 front section department does not receive the influence basically, the slot interval of wheel hub 10 middle section and tail section department reduces, the slot 30 of wheel hub 10 middle section and tail section department promotes the effect of vortex lifting, the vortex is more difficult to fall into in the slot 30 of wheel hub 10 middle section and tail section department, the drag reduction performance of wheel hub 10 middle section and tail section department obtains promoting.

It will be appreciated that the long and short grooves 32, 34 may also open onto the surface of the blade 20, for example, the pressure and/or suction sides 25, 26 of the blade 20, as desired. Because in the direction of blade 20 anterior segment to blade 20 tail section, the blade height reduces gradually, long slot 32 extends to blade 20 anterior segment from blade 20 tail section, short slot 34 extends to blade 20 anterior segment from blade 20 middle section, compare in only seting up long slot 32 on blade 20's surface, increase short slot 34 back on blade 20's surface, the slot 30 interval of blade 20 tail section department is unchangeable basically, the drag reduction performance of blade 20 tail section department is not influenced basically, the slot 30 interval of blade 20 middle section and blade 20 front section department reduces, the slot 30 of blade 20 middle section and anterior segment department promotes the effect of whirlpool lifting, the whirlpool is more difficult to fall into the slot 30 of blade 20 middle section and anterior segment department, the drag reduction performance of blade 20 middle section and anterior segment department obtains promoting.

The length ratio of the short grooves 34 to the long grooves 32 is 0.3-0.5, and the pneumatic performance of the impeller is best when the length ratio of the short grooves 34 to the long grooves 32 is 0.33.

The long grooves 32 and the short grooves 34 are alternately arranged in such a manner that one or two short grooves 34 are arranged between every two adjacent long grooves 32, or one or two long grooves 32 are arranged between every two adjacent short grooves 34. In the present embodiment, a short groove 34 is disposed between each two adjacent long grooves 32.

The number n of the grooves 30 between two adjacent blades 20 is less than or equal to 10 and less than or equal to 20.

The number of long trenches 32 may be equal to the number of short trenches 34 or the number of long trenches 32 may differ from the number of short trenches 34 by 1.

The total width of the grooves 30 in the single flow passage accounts for 20% -50% of the total length of the circumference of the outlet of the single flow passage, and the pneumatic performance of the impeller is optimal when the total width of the grooves 30 in the single flow passage accounts for 29.3% of the total length of the circumference of the outlet of the single flow passage.

It is understood that in embodiment 1, the number n of the grooves 30 between two adjacent blades 20 is 5 ≦ 12, and in embodiment 2, the number n of the grooves 30 between two adjacent blades 20 is 10 ≦ 20. In summary, it is sufficient if the number n of the grooves 30 between two adjacent blades 20 is 5 ≦ 20.

It is understood that in example 1, the total width of the grooves 30 in the single flow channel accounts for 15-30% of the total length of the circumference of the outlet of the single flow channel, and in example 2, the total width of the grooves 30 in the single flow channel accounts for 20-50% of the total length of the circumference of the outlet of the single flow channel. In summary, it is only necessary that the total width of the grooves 30 in a single flow channel accounts for 15% -50% of the total length of the outlet circumference of the single flow channel.

It is worth mentioning that the size of the impeller or the number of the blades 20 can be adjusted accordingly according to actual needs. Under the same impeller size, the volume of a single flow channel is reduced when the number of the blades 20 is increased, and at the moment, the number of the grooves 30 needs to be reduced, so that the situation that a triangular groove rib structure cannot be formed due to the fact that too many grooves 30 exist in the flow channel is avoided; conversely, as the number of blades 20 is reduced, the volume of a single flow passage is increased, and the number of grooves 30 is increased to prevent the vortex of the fluid from contacting the surface of the hub 10 to a greater extent, which would result in energy loss. According to the experiment, the aerodynamic performance and the resistance reduction effect of the impeller can be ensured to be maintained at an excellent level as long as at least one of the following conditions is met, as follows:

the number n of the grooves 30 between two adjacent blades 20 is less than or equal to 5 and less than or equal to 20;

the total width of the grooves 30 in the single flow channel accounts for 15% -50% of the total length of the circumference of the outlet of the single flow channel.

The performance improvement of the impeller after the groove 30 is added is obviously reflected on the indexes of the vacuum degree and the suction power of the fan, and the corrected vacuum degree and the suction power are obviously improved under the same condition, which is specifically shown in tables 1 and 2.

TABLE 1 Fan Performance after impeller addition of grooves 30

TABLE 2 performance of the fan before the impeller addition grooves 30

Note: "aperture" in table 1, 2 is testing arrangement's aperture, and the testboard need test performance under different apertures when general fan test.

When the test result of the testing device with the aperture of 14mm is taken as punctual, the performance efficiency of the fan is higher than 45%, and the performance of the impeller is excellent. The rotating speed of the impeller is fixed to be unchanged, the number of the grooves or the ratio of the total width of the grooves in a single flow channel to the total length of the circumference of the outlet of the single flow channel is changed, and the performances of the fan measured under the condition that the aperture of the testing device is 14mm are shown in tables 3 and 4 respectively.

TABLE 3 Fan Performance at fixed impeller speed and 14mm bore diameter for the test unit

Number of grooves	Flow dm ^3/s	Correction of vacuum degree kPa	Efficiency%
				0	14.49	15.92	42.05
5	14.4	16.55	45.21
				13	14.49	16.76	46.78
20	14.55	16.3	45.9
				25	13.97	15.76	42.31

TABLE 4 Fan Performance at fixed impeller speed and 14mm bore diameter for the test setup

According to the experimental result, the number of the grooves between two adjacent blades is 5-20, the total width of the grooves in a single flow channel accounts for 15-50% of the total length of the circumference of the outlet of the single flow channel, and the impeller has excellent overall performance in the range.

The testing device of the impeller comprises a pressure equalizing box, a thick steel hole disc, a manometer and a variable frequency coupling control cabinet. Wherein the thick steel orifice plate can be a flow regulating valve with 10 different pore diameters. During testing, the motor is started, drives the impeller to rotate, and tests the vacuum degree, the input voltage and the current in the voltage-sharing box. The flow is calculated by a calibrated orifice disc, and the aperture is continuously adjusted in the experiment to change the flow so as to realize the measurement under variable working conditions and further obtain the flow, the vacuum degree and the efficiency data.

Example 3

An embodiment 3 of the utility model provides a fan, the impeller that provides including fan shell, motor and embodiment 1, 2. The impeller is accommodated in the fan shell, and the output shaft of the motor is connected with the impeller and used for driving the impeller to rotate.

Example 4

Embodiment 4 of the present invention provides a vacuum cleaner, including the fan of embodiment 3. In the present embodiment, the cleaner is not limited to a bucket type, a horizontal type, an upright type, a handheld type cleaner, and a robot or other equipment having a dust suction function also belongs to the cleaner of the present application. Robots with dust collection functions, such as sweeping robots, mopping robots, and the like.

Compared with the prior art, the embodiment of the utility model provides an among impeller, fan and the dust catcher, through seting up slot 30 on the surface at the impeller, slot 30's trend is unanimous with the development direction of runner, can play the water conservancy diversion and smooth out with the fingers the effect of air current direction to the fluid motion, and gas operation is more smooth, promotes the impeller performance. In addition, the groove 30 can lift the vortex above the land of the groove 30, reduce the surface contact area of the vortex and the impeller, and reduce the energy loss caused by the contact of the vortex and the surface of the impeller, and the vortex can move along the groove 30 after being lifted, so that the energy loss caused by the transverse diffusion and development of the vortex is reduced, the fluid flow resistance is reduced, and the impeller performance is improved. In addition, the grooves 30 are formed in the surface of the impeller, the overall size of the impeller does not need to be changed, the impeller can be designed and processed on the existing impeller structure, and design cost is saved. In addition, the grooves 30 are formed in the surface of the impeller, so that partial materials of the impeller are removed, the weight of the impeller is reduced, the load of a load motor can be reduced, and the rotating speed of the impeller is indirectly improved.

In addition, the pressure surface 25 of the front section of the blade 20 is concave, the concave direction is opposite to the rotation direction of the impeller, so that the fluid drainage can be attached, the pressure surface 25 of the front section of the blade 20 can wrap the fluid at the air inlet, the leakage loss of the fluid at the air inlet can be reduced, the pressure surface 25 of the impeller under low flow is enlarged, the contact area between the pressure surface 25 and the fluid is increased, and the performance of the impeller is improved.

In addition, according to actual needs, the size of the impeller and the number of the blades can be adjusted correspondingly, and the aerodynamic performance and the drag reduction effect of the impeller can be maintained at a good level as long as the number n of the grooves 30 between two adjacent blades 20 is not less than 5 and not more than 20, or the total width of the grooves 30 in a single flow channel accounts for 15% -50% of the total length of the circumference of the outlet of the single flow channel.

In addition, since the surface of the impeller is generally irregular or non-uniform, the combination of the long grooves 32 and the short grooves 34 can be more adapted to the shape of the impeller to ensure the drag reduction effect, as compared to the case where only one kind of grooves 30 is provided on the surface of the impeller.

In addition, the extending direction of the surface of the hub 10 close to the trailing edge surface 22 of the blade 30 is changed to make the joint of the blade top surface 23 of the blade 30 and the trailing edge surface 22 in a round-angle smooth transition, so that the fluid which flows through the blade 30 to do work can be well guided to be basically parallel to the axial direction of the hub 10, the collision loss between the joint of the blade top surface 23 and the trailing edge surface 22 and the fluid is reduced, and the performance of the impeller is improved.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; within the idea of the invention, also technical features in the above embodiments or in different embodiments can be combined, steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications or substitutions do not depart from the scope of the invention in its corresponding aspects.

Claims (10)

1. An impeller comprising a hub and a plurality of blades arranged circumferentially of the hub;

the blades comprise pressure surfaces, the pressure surfaces are the surfaces of the blades facing the rotation direction of the impeller, the pressure surfaces of the front sections of the blades are concave, and the concave direction is opposite to the rotation direction of the impeller.

2. The impeller of claim 1, wherein said pressure surfaces of said vane tail sections are convex in the same direction as the direction of rotation of said impeller.

3. The impeller of claim 1, wherein the blade height decreases in a direction from the blade leading section to the blade trailing section.

4. The impeller of claim 2, wherein the curvature of the blade front section is less than the curvature of the blade rear section.

5. The impeller according to claim 1, characterized in that the blade has a rounded smooth transition at the junction of the blade tip face and the trailing edge face.

6. The impeller according to claim 1, wherein the surface at the trailing end periphery of the hub extends at an angle of 0 ° to 50 ° to the axial direction of the hub.

7. The impeller according to claim 2 or 3, characterized in that the blade tail section accounts for 5-30% of the total blade length.

8. The impeller according to claim 2 or 3, characterized in that the blade front section and the blade tail section are smoothly transitioned.

9. A fan comprising an impeller according to any one of claims 1 to 8.

10. A vacuum cleaner comprising the blower of claim 9.

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