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US-12618417-B2 - Blower

US12618417B2US 12618417 B2US12618417 B2US 12618417B2US-12618417-B2

Abstract

A blower may include: a prime mover, a fan configured to be driven by the prime mover, a blower duct through which an airflow generated by the fan flows; a plate portion disposed inside the blower duct and having side surfaces extending along a direction in which the airflow flows; and a protrusion protruding from the side surfaces near a downstream end of the plate portion in a direction blocking the airflow.

Inventors

  • Kazuki MIZUTA

Assignees

  • MAKITA CORPORATION

Dates

Publication Date
20260505
Application Date
20250603
Priority Date
20240717

Claims (14)

  1. 1 . A blower comprising: a prime mover; a fan configured to be driven by the prime mover; a blower duct formed as a straight tube portion through which an airflow generated by the fan flows in a frontward direction from a rear toward a front of the straight tube portion; a plate portion disposed inside the blower duct and having an upper side surface and a lower side surface extending along the frontward direction in which the airflow flows; and a protrusion protruding from at least one of the upper side surface and the lower side surface in an up-down direction orthogonal to the frontward direction in which the airflow flows, and extends in a right-left direction along the at least one of the upper side surface and the lower side surface, wherein the protrusion protrudes only from a downstream edge of the at least one of the upper side surface and the lower side surface, wherein a height of the protrusion in the up-down direction is within a range of 1% to 50% of a thickness of the plate portion in the up-down direction and a width of the protrusion in the frontward direction is within a range of 1% to 50% of a minimum width of the plate portion in the frontward direction.
  2. 2 . The blower according to claim 1 , wherein the protrusion comprises a plurality of protrusions, and the protrusions are arranged intermittently.
  3. 3 . The blower according to claim 1 , wherein the protrusion is arranged continuously.
  4. 4 . The blower according to claim 1 , wherein the protrusion is arranged only on one of the upper side surfaces and the lower side surface of the plate portion, and the protrusion is not arranged on the other of the upper side surface and the lower side surface of the plate portion.
  5. 5 . The blower according to claim 1 , wherein the prime mover is an electric motor.
  6. 6 . The blower according to claim 4 , wherein, the protrusion comprises a plurality of protrusions arranged intermittently, or the protrusion is arranged continuously, and the prime mover is an electric motor.
  7. 7 . The blower according to claim 1 , wherein the plate portion has a substantially right angle trapezoidal shape in a plan view from above.
  8. 8 . The blower according to claim 1 , wherein the thickness of the plate portion in the up-down direction is within a range of 0.1 mm to 5 mm.
  9. 9 . The blower according to claim 1 , wherein the height of the protrusion in the up-down direction is within a range of 0.15 mm to 1.5 mm.
  10. 10 . The blower according to claim 1 , wherein the minimum width of the plate portion in the frontward direction is within a range of 1 mm to 50 mm.
  11. 11 . The blower according to claim 1 , wherein the width of the protrusion in the frontward direction is within a range of 0.5 mm to 10 mm.
  12. 12 . The blower according to claim 1 , wherein, the thickness of the plate portion in the up-down direction is within a range of 0.1 mm to 5 mm, and the minimum width of the plate portion in the frontward direction is within a range of 1 mm to 50 mm.
  13. 13 . The blower according to claim 1 , wherein, the height of the protrusion in the up-down direction is within a range of 0.15 mm to 1.5 mm, and the width of the protrusion in the frontward direction is within a range of 0.5 mm to 10 mm.
  14. 14 . The blower according to claim 1 , wherein, the thickness of the plate portion in the up-down direction is within a range of 0.1 mm to 5 mm, the height of the protrusion in the up-down direction is within a range of 0.15 mm to 1.5 mm, the minimum width of the plate portion in the frontward direction is within a range of 1 mm to 50 mm, and the width of the protrusion in the frontward direction is within a range of 0.5 mm to 10 mm.

Description

REFERENCE TO RELATED APPLICATIONS This application claims priority from Japanese Patent Application No. 2024-114306 filed on Jul. 17, 2024. The entire content of the priority application is incorporated herein by reference. TECHNICAL FIELD The art disclosed herein relates to a blower. BACKGROUND ART Japanese Patent Application Publication NO. 2022-123186 describes a blower. The blower includes: a prime mover; a fan configured to be driven by the prime mover; a blower duct through which an airflow generated by the fan flows; and a plate portion disposed inside the blower duct and having side surfaces extending along a direction in which the airflow flows. SUMMARY In the above-mentioned blower, a vortex flow may be periodically generated at a downstream end of the plate portion. Because a frequency at which such vortex flow occurs varies according to a velocity of the airflow, the frequency varies according to a rotational speed of the fan. Due to this, depending on the fan rotational speed, the frequency at which the vortex flow occurs may coincide a vibratory resonant frequency of the plate portion and/or blower duct or an acoustic resonant frequency of the blower duct, all of which may result in loud noise. The present teachings provide an art configured to suppress generation of loud noise in a blower. A blower disclosed herein may comprise: a prime mover; a fan configured to be driven by the prime mover; a blower duct through which an airflow generated by the fan flows; a plate portion disposed inside the blower duct and having side surfaces extending along a direction in which the airflow flows; and a protrusion protruding from the side surfaces near a downstream end of the plate portion in a direction blocking the airflow. According to the above configuration, since the protrusion is disposed near the downstream end of the plate portion, periodical generation of vortex flow can be suppressed at the downstream end of the plate portion. Due to this, the vibratory resonance of the plate portion and/or blower duct or the acoustic resonance of the blower duct can be suppressed, by which generation of loud noise can also be suppressed. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 illustrates a perspective view of a blower 2 according to an embodiment. FIG. 2 illustrates a cross-sectional view of the blower 2 according to the embodiment. FIG. 3 illustrates a side view showing an inside of a fan case 24 in the blower 2 according to the embodiment. FIG. 4 illustrates a perspective view of an exhaust port 12 and its surroundings of the blower 2 according to the embodiment. FIG. 5 illustrates a cross-sectional view of the exhaust port 12 and its surroundings in the blower 2 according to the embodiment. FIG. 6 illustrates a longitudinal-sectional view of the exhaust port 12 and its surroundings in the blower 2 according to the embodiment. FIG. 7 shows a graph showing a relation between a motor rotation speed and a noise level with respect to the blower 2 according to the embodiment and a blower 2 according to a comparative example. FIG. 8 illustrates a cross-sectional view of an exhaust port 12 and its surroundings of a blower 2 according to a modification. FIG. 9 illustrates a cross-sectional view of an exhaust port 12 and its surroundings of a blower 2 according to another modification. FIG. 10 illustrates a cross-sectional view of an exhaust port 12 and its surroundings of a blower 2 according to yet another modification. DESCRIPTION Representative, non-limiting examples of the present disclosure will now be described in further detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the disclosure. Furthermore, each of the additional features and teachings disclosed below may be utilized separately or in conjunction with other features and teachings to provide improved blowers, as well as methods for using and manufacturing the same. Moreover, combinations of features and steps disclosed in the following detailed description may not be necessary to practice the disclosure in the broadest sense, and are instead taught merely to particularly describe representative examples of the disclosure. Furthermore, various features of the above-described and below-described representative examples, as well as the various independent and dependent claims, may be combined in ways that are not specifically and explicitly enumerated in order to provide additional useful embodiments of the present teachings. All features disclosed in the description and/or the claims are intended to be disclosed separately and independently from each other for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter, independent of the compositions of the features in the embodiments and/or the claims. In addi