TWI573551B - Centrifugal blowers and electric vacuum cleaners - Google Patents

Description

Centrifugal blower and electric vacuum cleaner

The present invention relates to a centrifugal blower having a centrifugal wing wheel and an electric vacuum cleaner using the centrifugal blower.

In the case where the radial dimension is limited, if the radius of the wing that works on the air is made large, the airflow that has just flowed out from the wing wheel must be bent into the axial direction. In the centrifugal blower of the related art, the outer peripheral portion of the main plate of the wing wheel is bent in the axial direction having the air outlet (see, for example, Patent Document 1).

[Prior patent documents] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 4-164194

In the conventional centrifugal blower as described above, since the outer peripheral portion of the main plate extends toward the outer side of the wing wheel, the radius of the wing of the airfoil is smaller than the radius of the wing. The power obtained from the radius of the wing wheel becomes small. Moreover, since the work of the main body on the air is small, the effect of the direction in which the air flows in the direction of the air outlet is also low.

The present invention is to solve the problems as described above. The purpose of the development is to obtain a centrifugal blower that can improve the air supply efficiency while reducing the loss caused by the direction of the airflow that has just flowed out from the wing wheel, and an electric vacuum cleaner using the centrifugal blower.

The centrifugal blower of the present invention includes: a motor; the centrifugal wing wheel has a first side plate, a second side plate facing the first side plate, and a plurality of blades held between the first side plate and the second side plate, and Driven by the motor; and forming a member covering the outer circumference of the wing wheel and forming a steering air path for changing the direction of the airflow just flowing from the wing wheel to the exit direction of the side of the axial direction of the wing wheel; 1 the side plate is located on the downstream side closer to the outlet direction than the second side plate; the wing has a trailing edge at the lateral end of the wing wheel; the trailing edge has a trailing edge tip located at the outermost side in the radial direction of the wing wheel, and The portion adjacent to the second side plate protrudes toward the outer side in the radial direction of the wing wheel toward the trailing edge tip; the axial position of the trailing edge tip is the axial position of the outer circumference of the first side plate and the axial position of the outer periphery of the second side plate The center is closer to the downstream side of the exit direction.

In the centrifugal blower of the present invention, the shape of the trailing edge of the wing protrudes from the portion adjacent to the second side plate toward the outer side in the radial direction of the wing end toward the trailing edge tip, and the axial position of the trailing edge tip is the first. The axial position of the outer circumference of the side plate and the center of the axial position of the outer circumference of the second side plate are closer to the downstream side in the outlet direction, so that the air supply efficiency can be improved while reducing the loss caused by changing the direction of the airflow immediately flowing from the wing wheel. .

1‧‧‧Motor

4‧‧‧wing wheel

6‧‧‧1st side panel

7‧‧‧2nd side panel

8‧‧‧ wings

8c‧‧‧ trailing edge

8d‧‧‧ trailing edge

10‧‧‧ Forming components

11‧‧‧Steering wind road

11a‧‧‧Steering Department

11b‧‧‧Drainage Department

13‧‧‧Silence

22‧‧‧ centrifugal blower

Fig. 1 is a cross-sectional view showing the centrifugal blower according to the first embodiment of the present invention along an axis.

Fig. 2 is a perspective view showing the wing wheel of Fig. 1.

Fig. 3 is a partially enlarged view showing a first diagram for explaining the characteristics of the outer peripheral shape of the wing wheel of the first embodiment.

Fig. 4 is a partially enlarged view showing a first diagram for explaining the relationship between the wing wheel and the steering air passage of the first embodiment and the shape of the steering air passage.

Fig. 5 is a view showing the configuration of an electric vacuum cleaner in which the centrifugal blower of Fig. 1 is built.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First embodiment

Fig. 1 is a cross-sectional view showing a centrifugal blower according to a first embodiment of the present invention along an axis (a cross-sectional view through a plane (a meridional plane) passing through a rotating shaft). The arrows shown in Fig. 1 indicate the flow direction of the air in this section.

The motor 1 has a motor body 2 and an output shaft 3 that protrudes from the motor body 2. The wing wheel 4 is fixed to the output shaft 3 and is driven by the motor 1 to rotate around the rotating shaft 5. The shaft 5 is aligned with the axis of the output shaft 3.

Here, the direction parallel to the rotating shaft 5 is referred to as an axial direction, and the direction away from the rotating shaft 5 is referred to as a radial direction. Therefore, in the first drawing, the vertical direction is the axial direction, and the horizontal direction is the radial direction.

The wing wheel 4 is centrifugally (centrifugal), and has a first side plate 6, a second side plate 7 facing the first side plate 6, and a sandwich between the first side plate 6 and the second side plate 7 and held therebetween. A plurality of wings 8

In this example, the first side plate 6 is coupled to the output shaft 3. Further, an intake port 7a for taking outside air into the wing wheel 4 is provided at the center of the second side plate 7. On the other hand, the second side plate 7 may be coupled to the output shaft 3, and the intake port may be provided to the first side plate 6.

The inner frame 9 is fixed to the end of the motor body 2 on the side of the wing wheel 4. The inner frame cylindrical portion 9a is formed on the outer peripheral portion of the inner frame 9.

The forming member (steering air passage forming member) 10 is disposed on the radially outer side of the wing wheel 4 and the inner frame 9. The forming member 10 covers the outer circumference of the wing wheel 4 and the inner frame 9. Further, the forming member 10 is formed on the outer side in the radial direction of the wing wheel 4 and the inner frame 9, and forms a direction for changing the direction of the airflow that has just flowed out from the wing wheel 4 to the direction of the exit of the side of the wing wheel 4. Wind road 11.

The direction of the exit is in the direction of the airflow toward the air passage 11, and is in the downward direction of the first figure. The first side plate 6 is located on the downstream side of the second side plate 7 in the outlet direction.

Fig. 2 is a perspective view showing the wing wheel 4 of Fig. 1. The arrow shown in Fig. 2 is the steering of the wing wheel 4. Each of the wings 8 is inclined to expand in diameter in a direction opposite to the turning of the wing wheel 4. In each of the wings 8, a surface that is turned toward the wing wheel 4 is referred to as a pressure surface 8a, and a surface that faces the direction opposite to the steering of the wing wheel 4 is referred to as a negative pressure surface 8b.

Further, each of the wings 8 has a trailing edge 8c located at the radially outer end of the wing wheel 4. The trailing edge 8c is connected to the outer periphery of the first side plate 6 and the edge of the outer peripheral wing 8 of the second side plate 7. Further, in Fig. 1, the trailing edge 8c is indicated by a line that is rotated and projected onto the meridional plane.

Figure 3 is a view for explaining the outer circumference of the wing wheel 4 of the first embodiment. A partial enlarged view of the first figure of the feature of the shape. Each trailing edge 8c has a trailing edge tip 8d located at the outermost side of the radial direction of the wing wheel 4. The trailing edge tip 8d is a point on the trailing edge 8c that becomes the largest diameter of the wing wheel 4.

Further, the shape of each trailing edge 8c is a smooth curve, and each trailing edge 8c is continuously enlarged from the portion 8e adjacent to the first side plate 6 and the portion 8f adjacent to the second side plate 7 toward the trailing edge tip 8d by the amount of protrusion. The way protrudes to the outside of the radial direction of the wing wheel 4.

Further, the axial position of each of the trailing edge tips 8d is closer to the axial position of the outer circumference of the first side plate 6 than the axial position of the outer periphery of the second side plate 7. In other words, the axial position of each of the trailing edge tips 8d is closer to the downstream of the outlet direction than the axial position of the outer circumference of the second side plate 7 and the center of the axial position of the outer periphery of the first side plate 6 (the straight line L1 of FIG. 3). side.

The outer peripheral radius of the first side plate 6 (R1 in Fig. 3) is larger than the outer peripheral radius of the second side plate 7 (R2 in Fig. 3). That is, the outer circumference of the first side plate 6 is located closer to the outer side in the radial direction of the wing wheel than the outer circumference of the second side plate 7.

Fig. 4 is a partially enlarged view showing a first diagram for explaining the relationship between the wing wheel 4 and the steering air passage 11 of the first embodiment and the shape of the steering air passage 11. The steering air passage 11 has a steering portion 11a located radially outward of the wing wheel 4, and a discharge pipe portion 11b located downstream of the steering portion 11a and guiding the airflow in the outlet direction. The air outlet 11c is provided at the downstream end of the discharge pipe portion 11b.

The discharge pipe portion 11b is an air passage formed between the inner frame cylindrical portion 9a and the forming member 10. Further, the cross-sectional shape of the discharge pipe portion 11b orthogonal to the rotating shaft 5 is annular.

The trailing edge tip 8d is located closer to the wing wheel than the outer circumference of the first side plate 6 4 radial outer side. That is, the maximum radius of the wing wheel 4 on the trailing edge 8c is larger than the outer circumference radius of the first side plate 6.

Further, the radius of the locus of the trailing edge tip 8d when the wing wheel 4 is rotated, that is, the maximum radius of the wing wheel 4 on the trailing edge 8c is the discharge tube portion 11b of the joint surface 12 of the turning portion 11a and the discharge pipe portion 11b. The inner diameter is larger and smaller than the outer diameter.

In Fig. 4, when the outer peripheral radius of the first side plate 6 is R1, the inner diameter of the discharge pipe portion 11b of the connecting surface 12 of the steering portion 11a and the discharge pipe portion 11b is R3, and the outer diameter is R4. When the maximum radius of the wing wheel 4 on the trailing edge 8c is RP, R1 < RP, and R3 < RP < R4.

The steering portion 11a is wide on the downstream side in the outlet direction and narrow on the upstream side. In other words, the inner diameter of the forming member 10 at the same position as the outer circumference of the first side plate 6 (the radial dimension R5 of the point Q1 in Fig. 4) is the same as the outer circumference of the second side plate 7 in the axial position. The inner diameter of the forming member 10 (the radial dimension R6 of the point Q2 in Fig. 4) is larger (R5 > R6). In this manner, the inner wall surface of the steering portion 11a is inclined such that the inner diameter becomes larger toward the downstream side in the outlet direction.

In the discharge pipe portion 11b, a plurality of stationary vanes 13 that reduce the rotational speed component of the airflow flowing out of the vane 4 and flowing into the discharge pipe portion 11b are arranged at intervals in the circumferential direction to recover the static pressure.

Next, explain the action. The wing wheel 4 is rotated together with the output shaft 3 by the action of the motor 1. The air inside the wing wheel 4 is pushed to the pressure surface 8a of the wing 8 to the radially outer side of the wing wheel 4. Thereby, the pressure is lowered in the central portion of the wing wheel 4, and the outside air is supplied from the intake port 7a to the inside of the wing wheel 4.

The air in the radially outer wing wheel 4 is from the first side plate 6 The outer circumference, the outer circumference of the second side plate 7, and the trailing edge 8c of the wing 8 form an outflow port of the wing wheel 4 that flows out of the wing wheel 4 and flows into the turning portion 11a of the steering air passage 11.

The air flowing out from the wing wheel 4 is drastically changed in the direction toward the exit direction in the steering portion 11a. The air whose direction is changed to the outlet direction passes through the discharge pipe portion 11b, and is discharged to the outside from the air outlet 11c.

In the steering portion 11a, in order to reduce the loss caused when the radial component of the airflow is bent in the axial direction, the radial radius of the steering air passage 11 is increased, and the radius of curvature of the curved portion is increased. However, in this case, since the overall size of the blower is increased, this method cannot be selected when the size of the blower is limited. Moreover, if the radius of the wing wheel 4 is made small, the required power cannot be obtained.

On the other hand, in the centrifugal blower according to the first embodiment, by adopting the configuration as described above, the bending loss when the direction of the outflow from the wing wheel 4 is changed to the axial direction can be changed in a limited radial dimension. Small, the input can be made smaller for the required power.

Hereinafter, details of the operation of the air in the vicinity of the trailing edge 8c of the blade 8 of the centrifugal blower according to the first embodiment will be described. In the centrifugal blower according to the first embodiment, the axial position of the trailing edge tip 8d is closer to the axial position of the outer periphery of the first side plate 6 than the axial position of the outer periphery of the second side plate 7. Further, the portion 8f of the trailing edge 8c adjacent to the second side plate 7 protrudes outward in the radial direction of the wing wheel 4 toward the trailing edge tip end 8d. Further, the side of the negative pressure surface 8b of the blade 8 is low in pressure and sucks in air from the surroundings.

Since the force of the air acting on the air 8 becomes higher as the peripheral speed becomes higher, the axial position is closer to the first axial position than the outer circumference of the second side plate 7 The position of the side panels 6 produces the greatest suction. Therefore, the air in the vicinity of the trailing edge 8c is biased from the second side plate 7 side toward the outlet direction. As a result, the pressure rise accompanying the collision of the inner wall of the steering portion 11a is reduced, and the bending loss is reduced. Therefore, the loss associated with the steering outside the radial direction of the wing wheel 4 is reduced, and the pair can be obtained. The required power is input into a small, highly efficient centrifugal blower.

Further, in the centrifugal blower according to the first embodiment, the trailing edge tip end 8d is located closer to the radially outer side of the wing wheel 4 than the outer circumference of the first side plate 6. Further, the maximum radius of the wing wheel 4 on the trailing edge 8c is larger than the inner diameter of the discharge pipe portion 11b of the connecting surface 12 of the turning portion 11a and the discharge pipe portion 11b, and is smaller than the outer diameter.

Therefore, the portion of the trailing edge 8c from the first side plate 6 to the trailing edge tip end 8d has a shape in the axial direction toward the outlet direction. It faces the connection surface 12 of the steering part 11a and the discharge pipe part 11b. Thereby, the air can be made to flow out from the rotating surface formed by the portion of the trailing edge 8c from the first side plate 6 to the trailing edge tip end 8d toward the connecting surface 12, and the bending loss can be made smaller. Therefore, a centrifugal fan of higher efficiency can be obtained.

Further, in the centrifugal blower according to the first embodiment, the outer peripheral radius of the first side plate 6 is larger than the outer peripheral radius of the second side plate 7. Therefore, in the radial direction of the wing wheel 4, from the outer periphery of the second side plate 7 to the outer periphery of the first side plate 6. The first side panel 6 side wing 8 is present, and the suction caused by the negative pressure surface 8b is relatively large. On the other hand, the second side plate 7 side wing 8 is partially present or absent, and the suction force caused by the negative pressure surface 8b is relatively small.

Therefore, the component of the airflow toward the exit direction can be obtained more, and the effect of the force of the air in the vicinity of the trailing edge 8c toward the exit direction can be made larger, and the bending loss can be made smaller. Therefore, higher efficiency can be obtained Centrifugal blower.

Here, the air flowing out from the wing wheel 4 has a radial velocity component and a rotational velocity component. Further, the centrifugal force caused by the rotational speed component is added to the inertial force caused by the radial velocity component, and the air flowing out from the wing wheel 4 is pressed against the inner wall of the steering portion 11a.

In the centrifugal blower according to the first embodiment, since the inner wall of the steering portion 11a is inclined to the radius on the outlet side and the radius on the opposite side is relatively small, the force of pressing the air against the inner wall in response to the inclination is caused by the inclination. A part of it is changed to a force along the inner wall toward the discharge pipe portion 11b.

Therefore, the pressure rise accompanying the collision with the inner wall of the steering portion 11a is made small, and the bending loss can be made small. Therefore, a centrifugal fan of higher efficiency can be obtained.

Further, in the centrifugal blower according to the first embodiment, the stationary blade 13 is provided between the connection surface 12 and the air outlet 11c of the discharge pipe portion 11b. Therefore, the boosting performance becomes high, and the boosting ratio of the wing wheel 4 can be lowered with respect to the required boosting performance, and the input of the wing wheel 4 can be reduced. Further, since the stationary blade 13 does not overlap the wing wheel 4 in the axial direction, the stationary blade 13 is provided, and it is not necessary to reduce the radius of the wing wheel 4. Therefore, for a limited radial dimension, a centrifugal blower with a high output can be used.

Fig. 5 is a view showing the configuration of an electric vacuum cleaner in which the centrifugal blower of Fig. 1 is built. The centrifugal fan 22 and the dust box 23 are housed in the cleaner body 21 in the same manner as in the first embodiment. Further, the rod-shaped tube 25 is connected to the cleaner body 21 via a flexible hose 24. At the end of the tube 25 opposite the hose 24, the head 26 is attached.

Driving the motor 1 of the centrifugal blower 22 to generate an air flow, whereby The air is sucked in from the air inlet of the head 26 together with the air. The inhaled air and dust pass through the tube 25 and the hose 24, and are then sent into the cleaner body 21. Then, the dust is stored in the dust box 23, and the air passes through the centrifugal blower 22, and is then discharged to the outside of the cleaner body 21.

By using the centrifugal blower 22 as described above, it is possible to achieve high output, high efficiency, and small size of the electric vacuum cleaner.

Further, in the above-described example, the centrifugal blower that transports air is shown, but the gas other than the air may be supplied, or the axial position of the trailing edge tip 8d may be the same as the axial position of the outer periphery of the first side plate 6.

Further, the centrifugal blower of the present invention can also be applied to other than a vacuum cleaner.

1‧‧‧Motor

2‧‧‧Motor body

3‧‧‧ Output shaft

4‧‧‧wing wheel

5‧‧‧ shaft

6‧‧‧1st side panel

7‧‧‧2nd side panel

7a‧‧‧ suction port

8‧‧‧ wings

8c‧‧‧ trailing edge

9‧‧‧ inside box

9a‧‧‧Inside frame cylinder

10‧‧‧ Forming components

11‧‧‧Steering wind road

Claims (5)

A centrifugal blower includes: a motor; a centrifugal wing wheel having a first side plate, a second side plate facing the first side plate, and a plurality of wings held between the first side plate and the second side plate And driving the motor; and forming a member covering the outer circumference of the wing wheel and forming an exit direction for changing the direction of the airflow just flowing from the wing wheel to the side of the axial direction of the wing wheel a steering air passage; the first side plate is located closer to the outlet side than the second side plate; the wing system has a trailing edge at an outer side end of the wing wheel; the trailing edge has a wing wheel a radially outermost trailing edge tip, and projecting from a portion adjacent to the second side plate and a portion adjacent to the first side plate toward the trailing edge tip toward a radially outer side of the wing wheel; the trailing edge tip The axial position is closer to the outlet side than the axial position of the outer circumference of the first side plate and the axial position of the outer circumference of the second side plate; the steering air path has a steering portion located at the wing wheel The outer side of the radial direction; and the outlet pipe portion are located in the steering Downstream, and guiding the airflow along the exit direction; the trailing edge tip is located closer to the outer side of the radial direction of the wing wheel than the outer circumference of the first side plate; the track of the trailing edge tip when the wing wheel rotates The radius is larger than the inner diameter of the discharge pipe portion at the joint surface of the steering portion and the discharge pipe portion It is smaller than the outer diameter of the discharge pipe portion. The centrifugal blower of claim 1, wherein the inner wall surface of the steering portion is inclined such that an inner diameter becomes larger toward the outlet side. A centrifugal blower according to claim 1 or 2, wherein the stationary vane for reducing the rotational component of the airflow and performing the static pressure recovery is disposed in the discharge duct portion. The centrifugal blower of claim 1 or 2, wherein the outer peripheral radius of the first side plate is larger than the outer peripheral radius of the second side plate. An electric vacuum cleaner comprising the centrifugal blower according to any one of claims 1 to 4.