JP6504754B2 - Electric blower and vacuum cleaner using the same - Google Patents

Description

  The present invention relates to an electric blower and a vacuum cleaner using the same.

  In recent years, in a cordless vacuum cleaner whose demand is rapidly increasing, an electric blower using a brushless motor is mounted in order to obtain a sufficient output even in a low voltage battery drive. In the brushless motor, in order to enhance the cooling effect, configurations as described in Patent Documents 1 and 2 are described.

  Patent Document 1 describes a cooling structure for opening a vent on the side surface of a motor housing.

  Patent Document 2 describes that even when an axially inclined opening provided in an end bracket is provided, the opening and the coil are disposed at substantially the same position when viewed from the radial direction.

JP, 2013-24134, A Unexamined-Japanese-Patent No. 5-231390

  In such small high-speed brushless motors, most of the losses are mechanical losses of the bearings. Therefore, while it is necessary to guide the cooling air to the inside of the motor, the need for cooling such as a coil, which has conventionally been required for cooling, is reduced.

  When a cooling structure in which the air vent is opened on the side surface of the motor housing as described in Patent Document 1 is adopted as such a motor, the amount of cooling air flowing into the motor may be insufficient, which may cause the temperature rise of the bearing.

  In addition, even when the axially inclined opening provided in the end bracket is provided as in Patent Document 2 above, when the opening and the coil are disposed at substantially the same position when viewed from the radial direction, Cooling air may cause a large ventilation loss. In addition, since the cooling air does not sufficiently strike the bearing on the end bracket provided with the opening that is not inclined in the axial direction, the temperature of the bearing on one side may be increased.

  The present invention has been made to solve the above-mentioned problems, and its object is to reduce the air flow loss and sufficiently cool the bearings, thereby achieving a high efficiency and long life electric blower and an electric cleaning using the same. To provide a machine.

In order to solve the above problems, in the present invention, an electric motor having a rotor having a shaft, a stator having a core and a coil, and an end bracket for holding a bearing that makes the shaft rotatable is provided. A blower, wherein a bridge extending from the bearing housing of the end bracket toward the outer periphery and a coil are disposed in substantially the same direction as viewed from the axial direction of the shaft, and an opening formed between the adjacent bridges An air gap formed by the adjacent coils is disposed in the space , and the opening does not face the coil .

  According to the present invention, it is possible to provide a highly efficient and long-lived electric blower and an electric vacuum cleaner using the same by lowering the air flow loss and sufficiently cooling the bearings.

It is a sectional view of an electric blower concerning one example of the present invention. (A) It is a perspective view of only the electric motor part which concerns on one Example of this invention. (B) It is an overhead view of only the electric motor part which concerns on one Example of this invention. It is a figure which shows the difference of the mechanical loss and copper loss by the difference in rotation speed. It is an external view which shows the electric blower and board | substrate which concern on one Example of this invention. It is sectional drawing of the electric blower which concerns on another Example of this invention.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 shows a cross-sectional view of the electric blower 1 of the present embodiment. The electric blower 1 includes a stator 4 having a core 2 and a coil 3, a rotor 6 having a shaft 5, and an end bracket 8 for holding a bearing 7 that makes the shaft 5 rotatable. An impeller 9 is attached to the shaft 5, a diffuser 10 is attached to one of the end brackets 8, a return 11 is provided on the end bracket 8 side of the diffuser 10, and the impeller 9 and the diffuser 10 are provided. The fan casing 12 is disposed to cover the Further, the maximum number of revolutions of the electric blower 1 is 70,000 or more.

  Of such an electric blower 1, a perspective view and an overhead view of only the motor portion 17 excluding the fan casing 12, the impeller 9, the diffuser 10 and the like are shown in FIGS. 2 (a) and 2 (b). The motor portion 17 comprises an end bracket 8 and a coil 3. The end bracket 8 is composed of a bearing housing 13 for fixing the bearing 7 and a bridge 14 extending outward from the bearing housing 13. More specifically, the end bracket 8 has a bearing cover portion 13a for covering the bearing 7, a diffuser mounting portion 13b which is a portion on the outer periphery of the bearing cover portion 13a to which the diffuser 10 is attached, and an opposite end for covering a part of the stator 4. It comprises an anti-end bracket attachment portion 13c, which is a portion to which the bracket 18 is attached, and a bridge 14 connecting the diffuser attachment portion 13b and the anti-end bracket attachment portion 13c.

  The bearing cover portion 13 a has a hole through which the shaft 5 passes and has a substantially cylindrical shape so as to cover the bearing 7. The diffuser attachment portion 13b is a substantially annular portion connected to the outer periphery of the bearing cover portion 13a. The anti-end bracket attachment portion 13c is a substantially annular portion. The bridge 14 is provided between the outer periphery of the diffuser attachment portion 13b and the inner periphery of the opposite end bracket attachment portion 13c. In the present embodiment, three bridges 14 are provided at substantially equal intervals (at approximately 120 ° intervals), and openings are provided between the adjacent bridges 14.

  The coil 3 is located in the space formed by the end bracket 8 and the anti-end bracket 18. The bridge 14 and the coil 3 are disposed at substantially the same position when viewed from the axial direction of the shaft 5.

  FIG. 3 is a diagram showing the difference between mechanical loss and copper loss due to the difference in rotational speed. Since the number of revolutions of the conventional electric blower as described in Patent Document 2 is 50,000 or less, as shown in FIG. 3, the ratio of copper loss generated in the coil and mechanical loss generated in the bearing is about 1 to 1 Met. Therefore, it is necessary to sufficiently cool the coil in order to protect the insulating coating of the coil, and the cooling air is applied to the coil by arranging the coil at the opening between the bridges. In such an arrangement of coils and bridges, while cooling of the coils is sufficient, there is a possibility that the ventilation loss may increase.

  On the other hand, in the electric blower 1 of the present embodiment, since the number of rotations is 70,000 or more, which is higher than the conventional one, as shown in FIG. The rate of copper loss is small, reducing the need for coil cooling. In addition, although the substantial resistance of the coil 3 may increase when rotating at a high speed, the increase in resistance can be suppressed by making the coil 3 have three or more coils. Thus, while reducing the copper loss of the coil, by arranging the positions of the coil 3 and the bridge 14 in the same direction as viewed from the axial direction of the shaft 5, an opening formed between the adjacent bridges 14 Since the air gaps formed by the adjacent coils 3 are arranged in the space, the ventilation loss is reduced and the efficiency of the electric blower 1 is improved. In other words, since the coil 3 does not reach the opening between the bridges 14, the ventilation loss is reduced and the efficiency of the electric blower 1 is improved.

  Furthermore, the bridge 14 is inclined in the axial direction, and when the axial component of the inclined portion and the radial component are compared, the diffuser 10 allows the electric blower 1 to be in the structure by making the axial component larger. Since a part of the entering wind flows directly to the vicinity of the bearing 7, the cooling performance of the bearing 7 is improved, and the life of the electric blower 1 is improved.

  Furthermore, the area of the opening between the bridges 14 is increased by configuring the bridge 14 to have a portion inclined in the axial direction and a portion extending in the axial direction as much as a portion protruding from the core 2 of the coil 3. On the other hand, the strength of the bridge 14 can be maintained. At this time, by making the height of the return 11 equal to or less than the height of the inclined portion of the bridge 14, it is possible to discharge the wind not necessary for cooling from the discharge port 15 of the end bracket 8, thereby reducing the air flow loss. Can do.

  In addition, when the bearings 7 are disposed on both sides in the axial direction of the stator 4, as compared with the conventional case where the bridge of the anti-end bracket 18 on the non-impeller side is configured substantially coplanar with the bearing housing By inclining the bridge of the anti-impeller side anti-end bracket 18 in the axial direction, the air flow loss can be further reduced.

  FIG. 4 is an external view showing an electric blower and a substrate according to an embodiment of the present invention. Further, when the bridge of the anti-end bracket 8 on the non-impeller side is inclined in the axial direction, the cooling air is discharged radially, so as shown in FIG. 4, the control board 16 disposed downstream of the electric blower Can be arranged in a plane perpendicular to the shaft 5 to reduce the air flow loss associated with the cooling of the control board 16.

  FIG. 5 shows a cross-sectional view of the electric blower of the second embodiment. By arranging the plurality of bearings 7 collectively on the impeller side of the stator 4, only one end bracket 8 is required, so cost reduction can be achieved. In addition, since the bearing housing 13 is axially elongated, the area in which the cooling air impinges is increased, and the cooling performance of the bearing is improved.

  By using the electric blower according to the first and second embodiments described above for the electric vacuum cleaner, it is possible to obtain high efficiency and long life of the electric vacuum cleaner.

Reference Signs List 1 electric blower 2 core 3 coil 4 stator 5 shaft 6 rotor 7 bearing 8 end bracket 9 impeller 10 diffuser 11 return 12 fan casing 13 bearing housing 13 a bearing cover portion 13 b diffuser attachment portion 13 c anti-end bracket attachment portion 14 bridge 15 outlet 16 Control board 17 Motor part 18 Anti end bracket

Claims (10)

An electric blower comprising: a rotor having a shaft; a stator having a core and a coil; and a motor having an end bracket for holding a bearing that makes the shaft rotatable.
The bridge extending toward the outer periphery from the bearing housing of the end bracket and the coil are disposed in substantially the same direction as viewed from the axial direction of the shaft, and adjacent to the opening formed between the adjacent bridges An air gap formed by the coils to be fitted is arranged ,
The electric blower does not have the coil facing the opening .
An electric blower according to claim 1, wherein
The motor-driven blower according to claim 1, wherein the bridge is inclined in the axial direction, and an axial component of the inclined portion is larger than a radial component.
It is an electric blower described in Claim 1 or Claim 2, Comprising:
An electric fan characterized in that bridges of end brackets disposed on both axial sides of the stator are both axially inclined.
It is an electric blower described in Claim 2 or Claim 3, Comprising:
An electric fan according to claim 1, wherein the bridge includes an axially inclined portion and a portion axially extended in the same degree as the coil end.
The electric blower according to any one of claims 2 to 4, wherein
The height of the return provided to the diffuser fixed to the end bracket is equal to or less than the height of the inclined portion of the bridge.
The electric blower according to any one of claims 1 to 5, wherein
Electric blower characterized in that the number of rotations is 70,000 or more
The electric blower according to claim 6, wherein
Electric blower characterized by having three or more coils
It is an electric blower described in any one of Claim 1 thru | or 7, Comprising:
An electric blower characterized in that a bearing is disposed on one side of the stator and the bracket is one.
The electric blower according to any one of claims 1 to 8, wherein
An electric blower characterized in that a control substrate is disposed in a direction substantially perpendicular to an axial direction.
  A vacuum cleaner using the electric blower according to any one of claims 1 to 9.