JP2008104794A - Electric vacuum cleaner - Google Patents

Abstract

A vacuum cleaner with high suction force and low noise is realized.
By providing a communication hole 80 in a partition plate 41, air flows from the return flow path 44 to the diffuser flow path 41, the flow in the return flow path 44 is made uniform, and the flow in the diffuser flow path 41 is achieved. The flow resistance was reduced and the high suction force was obtained. In addition, the excitation degree of the standing wave generated in the diffuser flow path was lowered, and the noise passing through the communication hole 80 was interfered with the sound passing through the return flow path 44 and the diffuser flow path 41 to reduce noise.
[Selection] Figure 5

Description

  The present invention comprises a vacuum cleaner body having an electric blower and a dust collecting part, a suction port having an opening to a surface to be cleaned, and a pipe line connecting the vacuum cleaner body and the suction port. The present invention relates to a household vacuum cleaner that sucks intake air into the dust collecting part.

  There is an improvement in suction power as a consumer need for a vacuum cleaner. Since the suction power representing the suction force is proportional to the product of the suction air volume and the suction pressure of the vacuum cleaner, the suction pressure must be increased in order to improve the suction power at the specified air volume point.

  And in order to increase a suction pressure, it is necessary to increase the pressure | voltage rise amount of an electric blower, or to reduce the pressure loss of conduits, such as a vacuum cleaner main body or a hose.

  Moreover, the mainstream of the vacuum cleaner dust collection method is the paper pack type, but the cyclone method is also increasing. With this method, the operating air volume is smaller than that of the paper pack type. Further, when the vacuum cleaner is actually used, the pressure loss further increases due to the accumulation of dust, so that the vacuum cleaner is operated in a lower air volume range.

  For this reason, electric blowers have been required to maintain a higher output in a wider operating range than before.

  In recent years, attempts have been made to improve the performance of a diffuser composed of a fixed guide vane (referred to as a diffuser guide) and a diffuser flow path partitioned by the guide blade in order to increase the pressure increase of the blower section.

  The diffuser is a device that decelerates the flow and recovers the pressure. If the deceleration is increased within a range where the flow is not separated, the performance is improved.

  However, even if the degree of deceleration is optimally adjusted to a specific airflow point, it is clear that if the airflow is operated at a different airflow point, the air-fluid flow separates from the diffuser wall and the performance deteriorates. It has become. Therefore, it has been desired to realize a blower capable of maintaining high performance over a wide air flow range.

  As an approach related to increasing the output of the blower, for example, in Patent Document 1 below, performance is improved by making a hole in a fan casing portion facing a curved flow path behind the diffuser and using it as an exhaust port.

  Conventionally, the flow from the diffuser passes through the curved flow path and then is supplied to the motor side and used as cooling air. In order to reduce the pressure loss that occurs during this cooling process and increase the blower output, This is a method of exhausting some air on the side.

  However, since the cooling air to the motor has decreased, the motor becomes hot and the efficiency on the motor side decreases, the reliability of the motor parts decreases, the wear of the commutator progresses, and the life may be shortened. It was.

  Since the cooling flow path has a cross-sectional area that changes in the flow direction, it plays a role in reducing noise generated by the blower. It had increased.

  As a method for reducing aerodynamic noise for the purpose different from such aerodynamic performance improvement, a method of providing a communication hole on a diffuser blade surface as shown in Patent Documents 2 and 3 below, and Patent Document 4 and As shown in FIG. 5, a method of opening a communicating hole in a diffuser meridian surface and a separately provided sealed space has been proposed.

  Further, as shown in Patent Document 6, a substantially triangular concave portion is provided on the outer periphery side of the diffuser to suppress axial flow separation in the return flow path and to equalize the flow speed in the return flow path. Thus, a method for reducing the loss has been proposed.

JP 2004-293460 A Japanese Patent No. 3510107 Japanese Patent No. 3646337 JP 2000-120599 A Japanese Patent Publication No.59-28154 Japanese Patent No. 3331877

  In the vacuum cleaner, as described above, it is desired that the suction work force is high in a wide flow rate range between the design air flow point and a lower air flow point. Furthermore, it is desirable that there are no side effects such as reduced efficiency on the motor side, reduced reliability, and increased noise.

  However, these phenomena have a strong trade-off relationship and are technically difficult to overcome.

  In order to solve this problem, it is only necessary to reduce the fluid loss without changing the air volume of the cooling air of the electric motor, maintaining the flow path structure other than the diffuser and the return, and reducing the flow in the diffuser Even if changes, it is sufficient if the method is always maintained close to the limit.

  An object of the present invention is to obtain a vacuum cleaner incorporating an electric blower having a diffuser peripheral structure that reduces noise and obtains a limit performance over a wide air flow range without impairing reliability.

  The present invention relates to an electric vacuum cleaner having an electric blower, wherein the electric blower includes an electric motor, a centrifugal impeller coaxial with a rotating shaft of the electric motor, and a flow rate decelerated toward an outer peripheral side of the centrifugal impeller. A fixed guide member for guiding an air flow; and a fan casing including the fixed guide member and the centrifugal impeller, wherein the fixed guide member surrounds a disk-shaped partition plate and an outer peripheral side of the centrifugal impeller. A plurality of diffuser guides arranged on the partition plate for guiding the air flow discharged from the centrifugal impeller in an outer circumferential direction, and disposed on the opposite side of the partition plate on the side opposite to the diffuser guide. A plurality of return guides forming a return flow path for guiding the motor to the electric motor, and located between the diffuser guide and the return guide side and the diffuser guide side The has a communication hole formed in the partition plate so as to communicate the communication hole, characterized in that the opening area of the return guide side to the diffuser guide side is different.

  Further, the present invention is characterized in that an opening area of the communication hole is larger on the return guide side than on the diffuser guide side.

  Further, the present invention provides a vacuum cleaner having an electric blower, wherein the electric blower is a motor, a centrifugal impeller coaxial with a rotating shaft of the electric motor, and a flow decelerated on an outer peripheral side of the centrifugal impeller. A fixed guide member for guiding an air flow to an electric motor; and a fan casing containing the fixed guide member and the centrifugal impeller. The fixed guide member includes a disc-shaped partition plate and an outer peripheral side of the centrifugal impeller. A plurality of diffuser guides that are arranged on the partition plate so as to surround and guide an air flow discharged from the centrifugal impeller in an outer circumferential direction, and disposed on the opposite side of the partition plate that is opposite to the diffuser guide, A plurality of return guides forming a return flow path for guiding an air flow to the electric motor, and located between the diffuser guide and the return guide side and the diffuser gas A communicating hole provided in the partition plate so as to communicate with the door side, the diffuser guide side opening end of the communication hole and the return guide side opening end of the communication hole being positioned in the vertical direction with respect to the partition plate From the point of view, it is characterized by a shift without overlapping.

  Further, the present invention comprises a vacuum cleaner body having an electric blower and a dust collecting part, a suction port having an opening to a surface to be cleaned, and a conduit connecting the vacuum cleaner body and the suction port, In the vacuum cleaner that sucks intake air from the suction port to the dust collecting part, the electric blower is a motor, a centrifugal impeller coaxial with a rotation shaft of the electric motor, and a flow rate on the outer peripheral side of the centrifugal impeller. A fixed guide member for guiding an air flow to the electric motor; and a fan casing containing the fixed guide member and the centrifugal impeller. The fixed guide member includes a disk-shaped partition plate and an outer peripheral side of the centrifugal impeller. A plurality of diffuser guides that are arranged on the partition plate so as to surround and guide the air flow discharged from the centrifugal impeller in the outer circumferential direction, and are arranged on the opposite side of the partition plate that is opposite to the diffuser guide. A plurality of return guides forming a return flow path for guiding the air flow to the electric motor, and the partition plate so as to be located between the diffuser guide and to communicate the return guide side and the diffuser guide side The communication hole is inclined and penetrated with respect to the axial center line of the rotating shaft.

  In the present invention, a pressure difference is generated on both sides of the communication hole provided between the diffuser flow path and the return flow path, and a flow is generated from the return flow path side to the diffuser flow path side. Separation of the air flow can be suppressed, the flow speed of the return flow path can be made uniform, and the pressure loss can be suppressed.

  Further, the air flow blown out to the diffuser flow path side acts on the main flow and can uniform the velocity distribution in the diffuser flow path, so that the pressure loss can be further reduced.

  Also, a standing wave is generated in the air flow direction of the flow path in the diffuser flow path, but part of the energy escapes to the return flow path side, so the standing degree of excitation can be lowered, and the rotation speed and blade Sinusoidal noise based on the product of the number of blades of the car, that is, the level of so-called blade noise can be reduced, and noise that is easily heard by pure tones can be reduced.

  Furthermore, since the frequency of the standing wave can be divided into two groups by making the number of communication holes smaller than the number of diffuser guides, the effect of further reducing the blade noise can be obtained.

  And since the sound wave which passed through the communicating hole and the sound wave which passed through the path | route from a diffuser flow path to a return flow path interfere, the noise produced by the disturbance of the fluid can also be reduced.

  Since the loss due to the air flow can be reduced as described above, it is possible to realize a vacuum cleaner that can realize a high suction force and low noise.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is an external perspective view of a vacuum cleaner showing an embodiment of the present invention. FIG. 2 is a cross-sectional view of the main body schematically shown. FIG. 3 is a cross-sectional view of the electric blower. FIG. 4 is a plan view excluding an impeller of the electric blower. FIG. 5 is a cross-sectional view of a main part of the blower portion of the electric blower. FIG. 6 is a plan view of the main part of the diffuser portion. FIG. 7 is an AA cross-section of the diffuser partition plate. FIG. 8 is a conceptual diagram showing the flow state of the diffuser flow path and the return flow path according to the prior art. FIG. 9 is a conceptual diagram showing the flow state of the diffuser channel and the return channel according to the present invention.

  As shown in FIG. 1, the electric vacuum cleaner in this embodiment includes a vacuum cleaner body 1, a hose 2, a hand operating part 3, a telescopic extension tube 4, and a suction mouth 5. A hose 2 is used for connection, and a suction port 5 is connected to the hand operating section 3 via an expansion / contraction extension tube 4 for use.

  The vacuum cleaner main body 1 incorporates an electric blower (described later), and sucks dust in the intake flow by sucking air from the suction port 5 by the suction force of the electric blower. The sucked dust-containing air is sucked into the vacuum cleaner main body 1 through the expansion / contraction extension pipe 4, the hand operating section 3, and the hose 2, and after the dust is separated by the paper pack part built in the main body, it is exhausted outside the vacuum cleaner. .

  Next, the cleaner body 1 will be described with reference to FIG.

  The vacuum cleaner main body 1 includes an electric blower 10 and a substrate 23 that controls the operation of the vacuum cleaner in an interior formed by a lower case 21 and an upper case 22.

  An anti-vibration rubber 24 is attached to the left side of the electric blower 10 in the drawing so as to come into contact with an annular ring 25 formed in the lower case 21 so as to be airtight.

  A dust collection chamber 12 is provided on the left side of the lower case 21 in the figure. The dust case lid 13 is airtight with the lower case 21 and a sealant (not shown).

  Further, the hose 2 and the hose insertion port 11 are connected and used in an airtight state through a sealing material (not shown). Moreover, the wheel 16 and the caster 15 are provided so that the cleaner body 1 can move.

  The flow of air in the cleaner body 1 will be described.

  When an operation signal is issued by the hand operation unit 3, the electric blower is operated in accordance with the operation mode processed by the substrate 23 and commanded.

  When the electric blower 10 rotates, an intake force is generated. Air containing dust flows into the paper pack 14 from the hose insertion port 11, dust is separated by the paper pack 14, and purified air flows into the dust collection chamber 12.

  It flows into the electric blower 10 from the dust collecting chamber 12, passes through the exhaust port of the electric blower, and is discharged out of the machine through exhaust ports (not shown) provided in the upper case 22 and the lower case 21.

  In the paper pack 14, the flow resistance increases when dust accumulates, so that the amount of air to be operated decreases and the rotation speed of the electric blower increases.

  Note that the paper pack 14 does not remove all the fine dust, but very fine things also flow into the electric blower 10, so a filter that filters fine dust is provided in the flow path to the exhaust port. Sometimes.

  Next, the electric blower 10 will be described with reference to FIG.

  The rotating shaft 50 is supported by the housing 53 and the end bracket 65 by two bearings 54. A commutator 52, an armature 51, and an impeller 30 are fixed to the rotation shaft. The end bracket 65 is fixed to the housing 53 by screws.

  A brush 62 is pressed against a commutator 52 by a coil spring (not shown) or the like with a suitable force on a brush holder 63 fixed to the housing 53.

  A stator 60 is provided outside the amateur 52 and is fixed to the housing 53. What remove | excluded said impeller 30 becomes an electric motor.

  The fixed guide member 100 having a function as a diffuser is provided so as to be interposed between the centrifugal impeller 30 and the electric motor.

  The partition plate 42 of the fixed guide member 100 includes a diffuser guide 40 and a return guide 43. The diffuser guide 40 is disposed so as to surround the outer peripheral side of the impeller 30, and forms a diffuser channel 41 that guides the air flow discharged from the impeller 30 in the outer peripheral direction in the outer peripheral direction.

  The return guide 43 is provided on the opposite side of the partition plate 42 on the opposite side of the diffuser guide 40, and forms a return flow path 44 that guides the air flow flowing through the diffuser flow path 41 to the electric motor.

  The diffuser guide 40 is integrated with the partition plate 42, a return guide 43 is integrally provided on the opposite side of the partition plate 42 from the diffuser guide 40, and a return flow path 44 is formed between the return guides 43. . These are collectively referred to as a fixed guide member 100.

  These are fixed to the surface perpendicular to the rotation axis of the end bracket 65 by screws. A fan casing 34 having an opening for the suction portion 35 is press-fitted to the outer peripheral side of the housing 53.

  An outer peripheral channel 45 is formed between the fan casing 34, the diffuser guide 40 and the return guide 43. Air flows from the diffuser channel 41 to the return channel 44 via the outer peripheral channel 45.

  The impeller 30, the fixed guide member 100, and the fan casing 34 are collectively referred to as a blower. This blower is a kind of centrifugal blower.

  Next, the air flow will be described.

  When the electric motor is energized, the rotating shaft 50 rotates and the impeller 30 rotates accordingly.

  The impeller 30 is a centrifugal impeller that uses centrifugal force. When the impeller 30 rotates at a high speed, the pressure rises in the impeller 30 and air flows into the impeller 30 from the suction portion 35 and passes through the impeller 30. Thus, a high-speed air stream is discharged to the outer peripheral side.

  This high-speed airflow flows into the diffuser flow path 41, is decelerated inside the diffuser flow path 41, and collects dynamic pressure as pressure.

  The flow from the diffuser flow path 41 is mixed in the outer peripheral flow path 45, the flow is turned toward the rotation axis direction, and flows into the return flow path 44. While changing the flow angle further in the radial direction in the return flow path 44, it is then guided to the motor cooling flow path 61.

  The motor cooling flow path 61 is provided between the housing 53 and the stator 60 and between the stator 60 and the amateur 51, and air for cooling the stator 60 and the amateur 51 flows.

  The flow from the motor cooling flow path 61 flows in the housing 53 to the right side in the figure, and after cooling the brush 62 and the commutator 52, the air flows out of the housing 53 from an exhaust port (not shown) provided in the housing 53. To be discharged.

  FIG. 4 is a plan view showing a state in which the impeller 30, the fan casing 34, and the end bracket 65 are removed.

  In this embodiment, the impeller 30 has eight blades 31, and has a main plate 32 and side plates 33 on both sides of the blades 31. The number of diffuser guides 40 is 13, and the number of blades of the impeller 30 is in a prime number relationship.

  This is because the flow from the impeller 30 has a velocity distribution in the circumferential direction and has a velocity distribution in the flow path divided by the blades 31 and is divided into groups corresponding to the number of blades. When it flows into the flow path 41, it acts on the diffuser guide 40 to cause pressure fluctuations, and noise having a frequency corresponding to the product of the number of blades and the number of rotations is generated, but has a velocity distribution generated in the impeller. This is to prevent the noise from increasing by shifting the timing at which the flow flows into the respective diffuser guides 40.

  The return flow path 44 is roughly divided into 10 flow paths. The outer peripheral channel 45 is a combination of a substantially triangular opening formed in the outer peripheral portion of the diffuser channel 41 and an annular channel formed outside thereof.

  In this outer peripheral flow path 45, the outward flow from the diffuser flow path 41 is changed to an inward flow, and air is sent to the return flow path 44. This is a so-called curved flow path. The return guide 43 is located inside the flat portion of the housing 53.

  Two of the return guides 43 are branched into two guides. This is because the end bracket 64 is on the motor side, so that this portion is avoided from being terminated and the flow is guided to the motor side.

  The motor cooling flow path 61 forms four flow paths between the stator 60 having a substantially rectangular outer shape and the housing 53 having a circular cross-sectional shape, and also flows between the stator 60 and the amateur 51. A road is formed.

  Accordingly, when the downstream side is viewed from the return flow path 44, the flow path is neither axially symmetric nor point-symmetric, and the flowability of each of the 10 return flow paths 44 is different. It can be said that.

  That is, it is considered that the flow rate is low and the flow velocity is low where the flow resistance is high, and the flow rate is high and the flow velocity is high where the flow resistance is low.

  This is because, when viewed downstream from the 13 diffuser channels 45, the influence is mitigated by the peripheral channel 45, but the flow rate is low, the flow rate is low, It is considered that the flow rate is high at a small place and the flow rate is high.

  The partition plate 42 has three communication holes 80 that are circular when viewed from the diffuser side connecting the diffuser flow path 41 and the return flow path 44. The three communication holes 80 are not provided in the flow paths adjacent to each other, and are provided in a distributed form in the circumferential direction in this embodiment.

  In other words, the communication holes provided between the diffuser guides 40 that form the diffuser flow channel 41 are in a distributed arrangement with an interval.

  Details of the communication hole 80 will be described below in detail with reference to FIGS.

  As shown in FIG. 5, the communication hole 80 has an opening area with a different size between the end surface on the diffuser side and the end surface on the return side, and the end surface on the return surface side is larger.

  Accordingly, the communication hole 80 has a circular shape on the end surface on the diffuser side, but has a shape close to an ellipse on the end surface on the return side.

  Further, the center position of the communication hole 80 is different between the diffuser side and the return side. That is, when the communication hole 80 is viewed from a direction perpendicular to the flat surface of the partition plate 42, the center position of the communication hole 80 appears to be shifted without overlapping between the diffuser side and the return side.

  Furthermore, the outer peripheral side of the communication hole 80 is formed so as to be inclined away from the rotary shaft 50 toward the return side.

  As shown in FIG. 6, the communication hole 80 extends in the outer peripheral direction so as to draw an arc, and the adjacent diffuser guides 43 overlap with each other at the beginning of overlapping and the downstream end. It is provided at a substantially intermediate position between the end of the overlap, and at a position near the portion that enters the outer peripheral surface of the diffuse guide 40 at a substantially triangular portion of the outer peripheral flow path 45.

  On the other hand, the return guide 43 is located away from the return guide and is provided at a diameter that is substantially the same as the diameter of the tip of the return guide 43.

  The communication hole 80 is centered in a direction along the diffuser guide 40 near the communication hole 80, that is, in the AA direction in which θ is 45 degrees in this embodiment, where θ is an angle from the BB direction. Is inclined with respect to a plane perpendicular to the rotation shaft 50, and the wall surface of the communication hole 80 is inclined at an inclination angle of 15 degrees on the outer peripheral side in the AA direction.

  FIG. 7 shows a cross-sectional view of the partition plate 42 cut in the AA direction. The left direction in FIG. 7 is the inner diameter side, and the right direction is the outer diameter side.

  The communication hole end surface 81 on the diffuser side end surface 83 side has a circular shape, and the communication hole end surface 82 on the return side end surface 84 side has a shape close to an ellipse, and is substantially straight between the both end surfaces. ing.

  Accordingly, an inclination is formed so as to extend from the diffuser flow path 41 side to the return flow path 44 side and spread to the outer peripheral side.

  The central axis of the opening is also inclined from the diffuser flow channel 41 side to the return flow channel 44 side so as to increase the outer diameter. Further, the area of the opening of the communication hole end face 82 on the return side end face 84 is larger than the area of the communication hole end face 81 on the diffuser side end face 83.

  The specific effects of this embodiment will be described below.

  The air flow that flows from the diffuser flow path 41 into the outer peripheral flow path 45 changes the flow direction toward the rotary shaft and flows into the return flow path 44. However, in order to reduce the size of the electric blower for a vacuum cleaner, Since the plate thickness of the outer peripheral portion of the plate 42 is as small as about 2 mm, the radius of curvature is only about 2 mm at the maximum, and there is not enough space for the flow to turn, the return flow path 44 as shown in FIG. Since the flow is separated from the partition plate 42 at the inlet side, the speed is increased on the end bracket 65 side in the return flow path 44, and the rotational axis direction in the return flow path 44 (the horizontal direction in the drawing) is increased. The speed distribution becomes large.

  On the other hand, in the case where the communication hole 80 is provided in the partition plate 42, the wall surface static pressure on the return flow path 44 side is higher than the wall surface static pressure of the diffuser flow path 41. Air is supplied to the flow path 41.

  By this air flow, the air flow in the return flow path 44 is attracted toward the partition plate, so that the magnitude of the velocity distribution in the return flow path 44 is relaxed. Accordingly, the speed of the high-speed flow portion where the pressure loss is likely to increase is reduced, thereby reducing the pressure loss.

  As shown in FIG. 7, the outer peripheral wall surface of the communication hole 80 provided in the partition plate 42 is slanted. Since the flow disturbance is not likely to occur near the entrance of the hole 80 and the air in the return flow path 44 is less disturbed and easily flows in, the flow rate of the communication hole 80 is increased, and the speed on the partition plate 42 side in the return flow path 44 is increased. The speed distribution can be reduced.

  Further, the flow ejected into the diffuser flow path 41 is less disturbed, and the speed can be lowered even at the same flow rate, so that it is difficult for the flow from the impeller 30 in the diffuser flow path 41 to be adversely affected. It is difficult for the performance of the channel 41 to deteriorate.

  Further, since the return flow path side opening of the communication hole 80 is larger than the diffuser side opening, the speed is low at the inlet and the speed is high at the outlet, so even if the flow is somewhat disturbed near the return side, the outlet Since the speed can be made uniform on the side and the turbulence can be reduced, the inflow from the return side channel 44 is further promoted, the action of suppressing the separation flow in the return channel 44 becomes stronger, and the maximum value of the speed becomes lower. , Pressure loss can be further reduced.

  The diffuser guide 40 is a stationary stationary blade, and the flow is decelerated in the diffuser flow path, and the dynamic pressure of the flow decreases as it travels through the flow path, and some of the reduced dynamic pressure is static. The pressure is recovered and the static pressure gradually increases.

  The averaged flow in the diffuser channel 41 is as indicated by an arrow C, but in reality, the flow rate on the concave surface side is high.

  In order to decelerate the flow most efficiently in the diffuser channel 41, it is necessary to design appropriately with the design air volume. At this time, the vehicle is greatly decelerated under the condition that the flow does not separate in the diffuser channel 41.

  For this reason, even if the air volume is larger or smaller than the designed air volume, the efficiency of decelerating and recovering it to the pressure is reduced, so that the operating range tends to be narrowed. In order to expand the operating range, it is also important to suppress the flow distribution generated in the diffuser channel 41.

  On the other hand, since the air flow blown into the diffuser channel 41 has a component flowing from the main plate side to the side plate side, the flow approaching the main plate side is pushed to the side plate side, so that the flow rate on the side plate side increases. In fact, since the flow can be made uniform, pressure loss can be reduced.

  Further, since the jet flow is inclined from the concave surface side to the convex surface side, air is supplied from the concave surface side having a high flow velocity to the convex surface side having a low flow velocity, and the velocity distribution in the diffuser channel 41 is more uniform. Therefore, the effect of reducing the pressure loss is increased.

  On the other hand, when the air volume is larger than the designed air volume or when the air volume is smaller than the designed air volume, the flow is easily separated and the velocity distribution is more easily attached, so that the loss is increased.

  Since the jet flow is inclined from the concave surface side to the convex surface side, the flow in the diffuser channel 41 can be brought close to the convex surface side having a low speed, which leads to suppression of the separation of the flow, so that the operating air volume range can be increased. There is also.

  As described above, since the pressure loss in the stationary flow path can be reduced, the suction power representing the suction force of the vacuum cleaner can be increased.

  In a flow path having stationary stationary blades such as this type of diffuser, noise having a higher harmonic frequency is generated with a frequency represented by the product of the number of impeller blades and the number of rotations as a basic order. This is referred to herein as a feather sound.

  As described above, since the blade sound is generated only at a specific frequency, it is easily amplified by the standing wave generated in the diffuser flow path 41, so that the sound becomes loud and is easy to reach the human ear.

  However, since the rotational speed operating range of the vacuum cleaner is wide from 300 rpm to 800 rpm, when it is amplified by the standing wave generated in the diffuser flow path 41, the frequency of the standing wave is at any rotational speed. The blade noise may increase in accordance with

  When the communicating hole 80 is provided in the diffuser flow path 41, the energy of the standing wave to be formed can be sent from the communicating hole 80 to the return flow path side, so that the resonance frequency slightly changes and the sound at the time of resonance is also reduced. Since an excitation level can be lowered | hung, the effect that blade sound can be reduced is acquired.

  In addition, since the number of communication holes is three with respect to the 13 diffuser channels, the standing wave generated in the diffuser channel 41 is divided into two types having different resonance frequencies. Therefore, the effect that the excitation level at the time of resonance can be lowered can also be obtained.

  In addition, the noise generated by the flow turbulence generated in the impeller or the like is distributed in a wide frequency range in the frequency spectrum, and this is referred to as turbulent sound.

  There are two noise propagation paths: one that passes through the diffuser flow path, passes through the path from the outer peripheral flow path to the return flow path, and one that passes from the diffuser flow path through the communication hole to the return flow path. When these are joined together on the return flow path 44 side, sound waves are overlapped, and this turbulent sound can be reduced within a certain frequency range.

  At this time, the communication hole has a smaller cross-sectional area than the diffuser channel 41, but the area of the communication hole 80 passing through the diffuser channel 41 is enlarged toward the return channel 44, so that it is the same as the effect of the horn. Since the level is slightly increased when exiting from the communication hole, the sound wave from the other propagation path is close to the sound volume, and the reduction effect due to the interference of sound that has passed through the two paths of turbulent sound is even greater. The effect of becoming is also obtained.

  Further, since the communication hole 80 increases in area toward the return flow path side, when the stationary part is formed by injection molding using a plastic material, the mold is moved to the left and right in FIG. Since the part can be taken out, there are obtained an effect that the mold is easily manufactured and an effect that the time required for the manufacturing can be reduced because the operation is small.

  Note that the cross-sectional shape of the communication hole 80 may be based on a square or triangular cross-sectional shape, and even if the hole is inclined obliquely from the diffuser flow path side to the return flow path side, the same effect can be obtained. can get.

  In this embodiment, the number of diffuser channels is 13. However, the number of diffuser channels or the number of return channels may be any number.

  Another embodiment of the present invention will be described with reference to the following drawings.

  Note that the description of the same configuration, operation, effect, and the like as in the first embodiment will be omitted, and here, what is unique to the present embodiment will be described. FIG. 10 shows the stationary part viewed from the diffuser channel side. FIG. 11 is a cross-sectional view of the communication hole taken along the line E-E ′ of FIG. 10.

  The stationary part has 13 diffuser guides 40 and 13 diffuser channels 41 and an annular outer peripheral channel 45 on the outer peripheral side thereof, and 10 return guides 43 and 10 return flows on the opposite side of the partition plate 42. A path 44 is provided.

  In addition, the outer periphery of the partition plate 42 is circular, and there is no triangular recess. The communication hole 80 is provided at a position of 40% from the inlet side of the overlapping portion of the diffuser flow paths, and is provided in all the 13 diffuser flow paths 41.

  The hole direction is the E-E ′ direction as shown in the figure, and the angle θ is 135 degrees.

  The cross-sectional shape of the communication hole 80 will be described with reference to FIG.

  The right side in the figure is the right side on the line E-E ′ of FIG. 10, and the flow flows from the inlet side of the return flow path 44 to the diffuser flow path 41 side.

  The cross-sectional shape of the communication hole 80 is divided into three regions. An inclined surface 86 is formed at an angle of 45 degrees from the outer peripheral side of the return flow channel side 44 (right side in FIG. 10), and then forms a substantially vertical line, and the opposite surface is the outer peripheral side of the return flow channel side 44 ( A substantially vertical surface 88 is formed from the right side of FIG. 10 and then forms an inclined surface 87 that forms an angle of 15 degrees.

  The diffuser flow path side end face 82 has an elliptical shape, and the diffuser side end face 81 has an elliptical shape with a little area. The vicinity of the center of the communication hole 80 has a circular shape with a diameter of 2 mm.

  In the present embodiment, since the position of the communication hole 80 is far from the outer peripheral side of the threshold plate 2, the separation flow becomes large when the flow turns to the return flow path 44 side.

  Moreover, since it becomes a position far from the entrance side of the return flow path 44, the hole shape is also enlarged. Therefore, the flow rate through the communication hole 80 is increased to strongly attract the separation flow in the return flow path 44 to the side plate 42 side.

  For this reason, the area of the communication hole 80 is increased, and the position of the overlapping portion of the diffuser channel 41 is set to a position of 40% of the length so that the static pressure difference between the wall surfaces of the diffuser channel 41 and the return channel 44 is reduced. I try to get bigger.

  The effects unique to this embodiment are as follows.

  Since the separation flow in the return flow path 44 is attracted to the partition plate by the flow flowing through the communication hole 80, the speed distribution in the return flow path 44 is reduced, and the speed of the fast flow area with a large loss is reduced. And pressure loss can be reduced.

  Further, since the slope is provided on the upstream side of the flow of the return flow path 44, the flow smoothly flows into the communication hole 80, so that the turbulence in the vicinity of the inlet can be suppressed.

  Further, the flow disturbance can be suppressed by forming the acceleration flow path in the communication hole 80.

  Furthermore, a portion where the area does not change is provided, and after the flow is adjusted here, the flow is decelerated by the enlarged flow channel having a small expansion angle, and flows into the diffuser flow channel 41.

  On the diffuser flow channel 41 side, the jet flow is directed to the convex surface side where the flow velocity is low and directed to the fan casing side, and the speed distribution in the diffuser flow channel 41 can be improved, so that the loss in the diffuser flow channel 41 can be reduced. .

  Moreover, since the flow direction is also 135 degrees and is directed in a direction along the flow in the diffuser flow path, it is difficult to make a bad effect on the deceleration of the flow in the diffuser flow path 41.

  As mentioned above, since the pressure loss in a stationary part can be reduced, the effect which can raise the suction work rate showing suction force is acquired.

  Since the energy of the standing wave generated in the diffuser flow path 41 is sent to the return flow path 44 through the communication hole, the excitation degree of the blade sound can be lowered and the blade sound can be reduced.

  At this time, since the communication hole is larger than that of the first embodiment, there is an effect that the degree of excitation is further reduced.

  In addition, since the sound wave passing through the communication hole 80 and the sound wave passing through the outer peripheral channel interfere with each other, the fluid sound generated in the impeller can be reduced, and the action also increases in the path difference. can get.

  Further, since the communication hole 80 increases in area toward the return flow path side, when the stationary part is formed by injection molding using a plastic material, the mold is moved to the left and right in FIG. Since the part can be taken out, there are obtained an effect that the mold is easily manufactured and an effect that the time required for the manufacturing can be reduced because the operation is small.

  Note that the cross-sectional shape of the communication hole 80 may be based on a square or triangular cross-sectional shape, and even if the hole is inclined obliquely from the diffuser flow path side to the return flow path side, the same effect can be obtained. can get.

  In the present embodiment, the number of diffuser flow paths is 13; however, the number of diffuser flow paths or the number of return flow paths may be any number.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an external perspective view of a vacuum cleaner according to a first embodiment of the present invention. 1. It is related to Example 1 of this invention, and is the principal part cross-sectional view which cut | disconnected the principal part of the vacuum cleaner main body of FIG. 1 is a sectional view of an electric blower according to Embodiment 1 of the present invention. FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view related to Example 1 of the present invention, in which a fan casing and an impeller of an electric blower are removed. FIG. 5 is a partial enlarged cross-sectional view of a blower unit according to the first embodiment of the present invention. FIG. 5 is an enlarged plan view of an integrated diffuser guide, partition plate, and return guide according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view showing a partially enlarged partition plate including a communication hole according to the first embodiment of the present invention. It is a schematic diagram which shows the flow of the air of a diffuser flow path of a prior art, an outer periphery flow path, and a return flow path. FIG. 6 is a schematic diagram illustrating the air flow in the diffuser flow path, the outer peripheral flow path, and the return flow path according to the first embodiment of the present invention. FIG. 10 is a plan view of a stationary portion as seen from the diffuser flow path, according to the second embodiment of the present invention. FIG. 11 is a cross-sectional view of the communication hole on the line E-E ′ of FIG. 10 according to the second embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Vacuum cleaner main body, 10 ... Electric blower, 30 ... Impeller, 34 ... Fan casing, 40 ... Diffuser guide, 41 ... Diffuser flow path, 42 ... Partition plate, 43 ... Return guide, 44 ... Return flow path, 45 ... Peripheral flow path, 50 ... rotating shaft, 80 ... communication hole.

Claims (6)

A vacuum cleaner main body having an electric blower and a dust collecting part, a suction opening having an opening to a surface to be cleaned, and a pipe line connecting the vacuum cleaner main body and the suction opening, and the dust collection from the suction opening by the electric blower In the vacuum cleaner that sucks the intake air into the part,
The electric blower includes an electric motor, a centrifugal impeller coaxial with a rotating shaft of the electric motor, a fixed guide member that decelerates a flow toward an outer peripheral side of the centrifugal impeller and guides an air flow to the electric motor, and the fixed guide member And a fan casing containing the centrifugal impeller,
The fixed guide member includes a disc-shaped partition plate and a plurality of diffuser guides arranged on the partition plate so as to surround an outer peripheral side of the centrifugal impeller and guiding an air flow discharged from the centrifugal impeller in an outer peripheral direction. Between the adjacent diffuser guides and a plurality of return guides disposed on the opposite side of the partition plate opposite to the diffuser guides and forming a return flow path for guiding the air flow to the electric motor. And having a communication hole provided in the partition plate so as to communicate the return guide side and the diffuser guide side,
The vacuum cleaner, wherein the communication hole has different opening areas on the return guide side and the diffuser guide side. The vacuum cleaner according to claim 1,
The vacuum cleaner characterized in that the opening area is larger on the return guide side than on the diffuser guide side. A vacuum cleaner main body having an electric blower and a dust collecting part, a suction opening having an opening to a surface to be cleaned, and a pipe line connecting the vacuum cleaner main body and the suction opening, and the dust collection from the suction opening by the electric blower In the vacuum cleaner that sucks the intake air into the part,
The electric blower includes an electric motor, a centrifugal impeller coaxial with a rotating shaft of the electric motor, a fixed guide member that decelerates a flow toward an outer peripheral side of the centrifugal impeller and guides an air flow to the electric motor, and the fixed guide member And a fan casing containing the centrifugal impeller,
The fixed guide member includes a disc-shaped partition plate and a plurality of diffuser guides arranged on the partition plate so as to surround an outer peripheral side of the centrifugal impeller and guiding an air flow discharged from the centrifugal impeller in an outer peripheral direction. Between the adjacent diffuser guides and a plurality of return guides disposed on the opposite side of the partition plate opposite to the diffuser guides and forming a return flow path for guiding the air flow to the electric motor. And having a communication hole provided in the partition plate so as to communicate the return guide side and the diffuser guide side,
When the diffuser guide side opening end of the communication hole and the return guide side opening end of the communication hole are viewed from the direction perpendicular to the flat surface of the partition plate, the center positions of both opening ends are shifted without overlapping. A vacuum cleaner characterized by that. A vacuum cleaner main body having an electric blower and a dust collecting part, a suction opening having an opening to a surface to be cleaned, and a pipe line connecting the vacuum cleaner main body and the suction opening, and the dust collection from the suction opening by the electric blower In the vacuum cleaner that sucks the intake air into the part,
The electric blower includes an electric motor, a centrifugal impeller coaxial with a rotating shaft of the electric motor, a fixed guide member that decelerates a flow toward an outer peripheral side of the centrifugal impeller and guides an air flow to the electric motor, and the fixed guide member And a fan casing containing the centrifugal impeller,
The fixed guide member includes a disc-shaped partition plate and a plurality of diffuser guides arranged on the partition plate so as to surround an outer peripheral side of the centrifugal impeller and guiding an air flow discharged from the centrifugal impeller in an outer peripheral direction. And a plurality of return guides disposed on the opposite side of the partition plate opposite to the diffuser guide and forming a return flow path for guiding the air flow to the electric motor, and the adjacent diffuser guides. And having a communication hole provided in the partition plate so as to communicate the return guide side and the diffuser guide side,
The vacuum cleaner, wherein the communication hole is penetrated with an inclination with respect to an axis of the rotary shaft. The electric vacuum cleaner according to claim 4,
The vacuum cleaner, wherein the communication hole is inclined so that the return guide side is away from the axis of the rotating shaft. The electric vacuum cleaner according to claim 5,
An electric vacuum cleaner characterized in that the communication hole extends in an outer peripheral direction so as to draw an arc, and the communication hole is arranged at a substantially intermediate position in a range where the adjacent diffuser guides overlap in the extending direction.

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