JP2018145897A - Electric blower and vacuum cleaner including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric blower capable of securing a clearance between a spring outer diameter and a bearing cover inner diameter for imparting preload to an outer ring of a bearing, to avoid mutual contact, and a vacuum cleaner including the electric blower.SOLUTION: An electric blower 200 includes: a rotational shaft 207 provided in a rotatable manner; a centrifugal impeller 203 provided at one end of the rotational shaft; a rotor core 209 provided on a reverse side of the rotational shaft with respect to the centrifugal impeller; a rotor 230 comprising at least one bearing part provided between the centrifugal impeller and the rotor core; and a bearing cover 215 covering the bearing part. The bearing part has a pair of bearings 212 aligned in an axial direction. Between the bearings, a spring 217 configured to impart preload is arranged, and the spring is formed into a hand drum shape.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an electric blower and a vacuum cleaner equipped with the electric blower.

In recent years, the demand for cordless stick cleaners has increased. Since the cordless stick cleaner is driven by using a low-voltage battery for weight reduction, an electric blower using a brushless motor is mounted in order to obtain a sufficient suction force. Moreover, in order to achieve weight reduction by miniaturization of the main body, the electric blower is also required to be miniaturized. Regarding the miniaturization of the electric blower, the outer diameter of the fan can be reduced by increasing the rotational speed of the electric blower. Therefore, there are many examples in which the rotation speed of the brushless motor is set to 80,000 min ⁻¹ or more.

However, there is a problem in that the temperature of the electric blower rises because the air volume generated by reducing the outer diameter of the fan is reduced, and the frictional heat at the bearing is likely to increase due to high speed rotation. Also, vibration and noise problems caused by driving at a high speed of 80,000 min ⁻¹ or higher. Furthermore, since the structure is small, the dimensional tolerance of each part is small, and there is no fitting clearance, so there is a problem of assembling.

  As a prior art, for example, there is one disclosed in Japanese Patent Application Laid-Open No. 2016-138510 (Patent Document 1).

  An electric blower disclosed in Japanese Patent Laid-Open No. 2016-138510 is attached to a rotating shaft that is rotatably provided, a rotor core that is integrally formed with one end of the rotating shaft, and the other end of the rotating shaft. A centrifugal impeller, a bearing to which the rotating shaft is attached between the rotor core and the centrifugal impeller, a bearing cover including the bearing, and a resin housing integrally formed with the bearing cover, A diffuser blade, a diffuser having a return guide blade on the back surface of the diffuser blade, a fan casing that encloses the centrifugal impeller and the diffuser, and a heat sink is provided on the outer periphery of the bearing cover.

JP 2016-138510 A

  In Patent Document 1 described above, a spring is disposed in contact with a plurality of bearings disposed between the rotor core and the centrifugal impeller in order to apply a preload to the outer ring of the bearing. Therefore, in the case of a cylindrical coil spring, in order to apply a preload to the outer ring of the bearing, it is necessary to be a coil spring having an outer diameter approximately equal to that of the bearing. Then, if the clearance from the inner diameter of the bearing cover holding and holding the bearing is small, depending on the buckling of the spring and the deviation of the arrangement, there is a risk of difficulty in assembling due to contact between the bearing cover and the spring during assembly. Furthermore, after the assembly, when the electric blower is driven in a state where the spring is in contact with the bearing cover, vibrations are transmitted and rub against each other, which may cause abnormal noise. The bearing cover is made of aluminum die casting in order to reduce the weight and dimensional accuracy and to nullify the influence of the magnetic force of the adjacent rotor core (magnet). Therefore, if the spring is made of a material having rigidity higher than that of aluminum, and the vibration is transmitted with the bearing cover and the spring in contact with each other when the electric blower is driven after assembly, the aluminum having low rigidity is rubbed against each other. The bearing cover is cut and fine aluminum powder is produced. This may enter the gap between the inner ring and the shield of the adjacent bearing, causing damage to the internal parts of the bearing, which may cause abnormal bearing noise and early life.

  The present invention includes a rotating shaft provided rotatably, a centrifugal impeller provided at one end of the rotating shaft, a rotor core provided on a side opposite to the centrifugal impeller of the rotating shaft, the fan, A rotor comprising at least one bearing provided between the rotor cores, a bearing cover containing the bearing, a resin housing integrally formed with the bearing cover, and an outer peripheral side of the rotor core. A stator having a core and a coil, a diffuser fixed to the outer periphery of the centrifugal impeller by the housing, and a fan casing fitted to the housing so as to cover the centrifugal impeller and the diffuser In the electric blower constituted by, a pair of bearings are arranged in alignment in the axial direction, and a spring for applying a preload is arranged between the bearings, The shape of serial springs are electric blower, which is a hourglass shape.

  According to the present invention, since the clearance between the outer diameter of the spring and the inner diameter of the bearing cover can be ensured and mutual contact can be avoided, the electric blower capable of improving assemblability, reducing noise and extending the service life, and An on-board vacuum cleaner can be provided.

FIG. 2 is an exploded perspective view showing the rotor assembly of the electric blower according to the first embodiment. 1 is an exploded perspective view showing an electric blower according to Embodiment 1. FIG. Sectional drawing which shows the electric blower concerning Embodiment 1. FIG. FIG. 2 is a shape diagram (a) of a spring according to the first embodiment and a shape diagram (b) of a conventional spring. FIG. 2 is a configuration cross-sectional view (a) of the bearing portion and the bearing cover according to the first embodiment, and a configuration cross-sectional view (b) of the bearing portion and the bearing cover according to the conventional shape. The vacuum cleaner carrying the electric blower in Example 2 is shown, (a) is a perspective view at the time of using as a stick type, (b) is a side view at the time of using a vacuum cleaner as a handy type. It is a longitudinal cross-sectional view of the cleaner body which mounts the electric blower in Example 2. FIG.

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

[Embodiment 1]
FIG. 1 is an exploded perspective view showing a rotor assembly of an electric blower in this embodiment.

  As shown in FIG. 1, the rotor assembly 230 includes a centrifugal impeller 203, a rotating shaft 207, a rotor core 209, bearings 212 and 212, a ring member 213, a spring 217, and a cover 250. The bearings 212 and 212 and the spring 217 constitute a bearing portion.

  The centrifugal impeller 203 is fixed to one end of the rotating shaft 207 in the axial direction G. In this embodiment, the centrifugal impeller 203 is press-fitted and fixed to the rotary shaft 207. However, a screw may be provided at the end (tip) of the rotary shaft 207, and the centrifugal impeller 203 may be fixed by a fixing nut.

  The rotor core 209 is provided at the end of the rotating shaft 207 in the axial direction G opposite to the end where the centrifugal impeller 203 is fixed (the other end of the rotating shaft 207 in the axial direction G). The rotor core 209 is made of, for example, a rare earth bond magnet. A rare earth bond magnet is made by mixing a rare earth magnetic powder and an organic binder. As the rare earth bond magnet, for example, a samarium iron nitrogen magnet, a neodymium magnet, or the like can be used. Further, the rotor core 209 is integrally formed with the rotating shaft 207. The rotor core 209 is covered with a cover 250 in contact with the peripheral surface. The cover 250 is formed by forming a non-magnetic thin plate into a cylindrical shape, and is constituted by, for example, a mixture of stainless steel with a large amount of nickel.

  The ring member 213 is used for balance adjustment, and is provided at the end of the rotating shaft 207 on the rotor core 209 side. The ring member 213 has a specific gravity larger than that of the rotor core 209 and is made of a nonmagnetic material. For example, it can be formed by a sintered product (sintered body) such as a copper material or by machining. The ring member 213 is not limited to copper as long as it has a specific gravity greater than that of the rotor core 209 and is a nonmagnetic material.

  Bearings 212 and 212 are provided on the rotary shaft 207 between the centrifugal impeller 203 and the rotor core 209. The bearings 212 and 212 are spaced apart from each other in the axial direction, and rotatably support the rotating shaft 207. A coiled spring 217 is provided between the bearings 212 and 212 to apply a preload to the outer rings of the bearings 212 and 212.

  FIG. 2 is an exploded perspective view showing the electric blower according to the present embodiment.

  In the stator 240, a coil 211 is wound around the stator core 210, and together, a phase winding is formed. The phase winding is electrically connected to a circuit unit (not shown) provided in the electric blower 200.

  The housing 208 is made of synthetic resin, and includes a bearing cover 215 that encloses a bearing portion of the rotor assembly 230 and insert molding. On the outer periphery of the bearing cover 215, a plurality of cooling fins 27 that are long in the direction of the rotation axis, which is a heat sink for cooling the bearing 212, are provided. The bearing cover 215 is made of a non-magnetic metal material, and is preferably advantageous in terms of weight reduction and heat dissipation. In this embodiment, an aluminum material is used.

  A screw hole 28 extending in the axial direction G is formed in the support portion 26 of the housing 208. A fixing screw 218 can be screwed into the screw hole 28, and the diffuser 205 is fixed to the housing 208 by the screwing of the fixing screw 218.

  Further, the housing 208 is formed with an opening 34 through which air flows into the housing 208 and an exhaust port 35 through which air is discharged to the outside of the electric blower 200. The stator 240 disposed at the end of the housing 208 in the axial direction G is fixed to the housing 208 by a fixing screw 219.

  The fan casing 204 is configured to cover the diffuser 205 and the centrifugal impeller 203 of the rotor assembly 230 and is fitted to the housing 208.

  FIG. 4 is a sectional view of the shape of the spring according to the first embodiment. FIG. 4A shows the spring shape of the present invention, in which both ends of the spring 217 have the maximum outer diameter, and the outer diameter of the spring 217 decreases from the both ends toward the center in the axial direction. It is a pinching spring that has a minimum outer diameter. FIG. 4B shows a conventional coil shape, which is a cylindrical coil spring having the same outer diameter through both ends of the spring 217.

  FIG. 5 is a structural cross-sectional view of a bearing portion of the electric blower according to the first embodiment. Fig.5 (a) is sectional drawing of the bearing part using the pinch-shaped spring concerning this invention of Fig.4 (a). FIG.5 (b) is sectional drawing of the bearing part using the conventional cylindrical spring of FIG.4 (b). As can be seen from a comparison between FIGS. 5A and 5B, FIG. 5A shows that the spring 217 is formed in a zigzag shape. A clearance CL is formed between the inner diameter of the cover 215 and the outer diameter of the spring 217. For this reason, at the time of assembly, when inserting the rotor assembly 230 into the bearing cover 215, it becomes difficult to contact the spring, so that the assemblability is improved. In addition, when the electric blower 200 is driven after assembly, even if vibration is transmitted in a state where the bearing cover 215 and the spring 217 are in contact with each other, a larger clearance CL is ensured than the conventional cylindrical spring. They are not in contact with each other, and it is possible to eliminate the generation of fine powder due to abnormal noise due to the contact state and rubbing of the parts with low rigidity. Thereby, the assemblability of the electric blower can be improved, noise can be reduced, and the life can be extended.

[Embodiment 2]
Hereinafter, as a second embodiment, a vacuum cleaner equipped with an electric blower including a motor using a spring according to the present invention will be described with reference to the drawings.

  In the following, a case where the present invention is applied to a rechargeable vacuum cleaner 400 that can be used by appropriately switching between a stick type and a handy type will be described as an example. However, various types such as only a stick type and only a handy type are described. It can be applied to a vacuum cleaner.

  FIG. 6 shows an electric vacuum cleaner equipped with an electric blower according to the present embodiment, wherein (a) is a perspective view when used as a stick type, and (b) is a side view when the electric vacuum cleaner is used as a handy type. is there.

  As shown in FIG. 6A, a vacuum cleaner 400 is a vacuum cleaner that houses a dust collection chamber 401 that collects dust and an electric blower 200 (FIG. 7) that generates a suction airflow necessary to collect dust. Main body 410, telescopic pipe 402 that is extendable with respect to cleaner body 410, grip portion 403 that is pivotally provided at one end of telescopic pipe 402, and on / off of electric blower 200 that is provided at grip portion 403 The switch part 404a and the switch part 404b (refer FIG.6 (b)) which perform are comprised.

  The vacuum cleaner 400 shown in FIG. 6A is in a stick state, in which the telescopic pipe 402 is extended and the grip portion 403 is rotated to the opposite side to the telescopic pipe 402 and locked. Further, a suction body 405 is attached to the other end of the cleaner body 410, and the cleaner body 410 and the suction body 405 are connected by a connection portion 406.

  The vacuum cleaner 400 shown in FIG. 6B is in a handy state, in which the stretchable pipe 402 is housed in the cleaner body 410 and the grip portion 403 is rotated toward the stretchable pipe 402 side. Further, the rotated grip portion 403 is clamped by a clamp member 407 provided on the upper surface of the cleaner body 410. Further, a suction body (gap nozzle) 408 is attached to the other end portion of the cleaner body 410, and the cleaner body 410 and the suction body 408 are connected by a connection portion 406.

  In the electric vacuum cleaner 400 described above, by operating the switch portion 404a (see FIG. 6A) or the switch portion 404b (see FIG. 6B) of the grip portion 403, the electric motor housed in the cleaner body 410 is operated. The blower 200 (see FIG. 7) is activated to generate a suction airflow. Then, dust is sucked from the suction bodies 405 and 408 and collected in the dust collection chamber 401 of the cleaner main body 410 through the connection portion 406.

  FIG. 7 is a longitudinal sectional view of a vacuum cleaner main body equipped with the electric blower in the present embodiment. FIG. 7 shows a handy state in which the suction body 408 is removed from the cleaner body 410.

  As shown in FIG. 7, the vacuum cleaner main body 410 includes an electric blower 200 that generates a suction force, a battery unit 420 that supplies electric power to the electric blower 200, and a driving circuit 430.

  The air sucked from the suction bodies 405 and 408 (see FIGS. 6A and 6B) passes through the flow path 440 (see FIG. 6A) provided in the cleaner main body 410 and the electric blower 200. It is sent to the dust collection chamber 401 arranged in the front and collected in the dust collection chamber 401. The air after the dust is separated in the dust collection chamber 401 passes through the electric blower 200 and the drive circuit 430 and is discharged to the outside from an exhaust port (not shown) formed in the cleaner body 410.

  By these vacuum cleaners equipped with an electric blower equipped with a motor using a spring according to the present invention, it is possible to provide a low-noise and long-life vacuum cleaner.

  As described above, the rotor and the motor using the clutch spring according to the present invention have been described in detail with reference to the best mode and examples. It should be noted that the content of the present invention is not limited to the above-described embodiments, and can be appropriately modified or changed within a range not departing from the spirit thereof.

13 Diffuser blade 14 Return guide blade 26 Support portion 27 Cooling fin 28 Screw hole 29 Recess 30 Bridge 31 Frame 32 Screw hole 34 Open 35 Exhaust port 36 Inclined portion 200 Electric blower 201 Blower portion 202 Electric motor portion 203 Centrifugal impeller 203a Outer peripheral edge portion 204 Fan casing 205 Diffuser 206 Suction port 207 Rotating shaft 208 Housing 209 Rotor core 210 Stator core 211 Coil 212 Bearing 213 Ring member 214 Positioning sleeve 215 Bearing cover 217 Spring 218 Fixing screw 219 Fixing screw 230 Rotor assembly 240 Stator 250 Cover 270 Motor 400 Vacuum cleaner 410 Vacuum cleaner body G Axial direction

Claims (2)

  A rotating shaft provided rotatably, a centrifugal impeller provided at one end of the rotating shaft, a rotor core provided on the opposite side of the centrifugal impeller of the rotating shaft, and between the fan and the rotor core A rotor comprising at least one bearing portion provided; a bearing cover including the bearing portion; a resin housing integrally formed with the bearing cover; and a core and a coil disposed on an outer peripheral side of the rotor core A stator having an outer periphery of the centrifugal impeller, a diffuser fixed by the housing, and a fan casing fitted to the housing so as to cover the centrifugal impeller and the diffuser. In the electric blower, a pair of bearings are arranged in the axial direction in the bearing portion, and a spring for applying a preload is arranged between the pair of bearings. Electric blower shape of the spring is characterized by a hourglass shape.   A vacuum cleaner comprising the electric blower according to claim 1.

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