Blower / vacuum tool

Abstract

A blower / vacuum tool is provided having reduced fan blade noise. The tool includes a body extending between a first end and a second end and defining an airflow conduit therethrough; and a fan assembly. The fan assembly includes an axial fan having a plurality of fan blades n b and a motor rotatably connected to the axial fan. When n b is in the range of 17-45, the blade solidity of the axial fan is in the range of 0.0464n b ≤ blade solidity ≤ 0.089n b , the blade solidity being calculated by the equation blade solidity = c / s, where c is the length of the chord line of the fan blade and s = 2πr m / n b , r m is the average radius of the fan blade. The blade pass frequency of the fan assembly is greater than 6 KHz when the motor is operating at a revolutions per minute (RPM) of between 21,000-38,000, the blade pass frequency being calculated by the equation

Description

[0001] This application is a divisional application of utility model patent application No. 202422555175.0, filed on October 22, 2024, entitled "Blower / Vacuum Device Tool".

[0002] Cross-references to related applications

[0003] This application claims priority to U.S. Provisional Patent Application No. 63 / 592,473, filed October 23, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0004] This disclosure generally relates to outdoor tools, such as blowers, vacuum tools and / or combined blower / vacuum tools, and more particularly to improved fan blade noise in such tools. Background Technology

[0005] Outdoor tools such as blowers, vacuum tools, and combination blower / vacuum units (collectively referred to as "blower / vacuum tools") are typically used to concentrate debris (such as leaves) using a blowing function and / or to collect debris using a suction function. Homeowners frequently use these blowers to clean their yards and outdoor spaces. Battery-powered blower / vacuum tools are particularly popular due to their portability. However, there is a desire to improve various aspects of blower / vacuum tools, especially handheld blower / vacuum tools.

[0006] One known problem with blower / vacuum equipment tools is the noise level generated by the fan assembly, particularly the fan blade noise produced during operation. Due to the natural frequency arrangement of the auditory canal, the range of frequencies most sensitive to human hearing is typically between 2-6 kHz, while frequencies between 8-12 kHz are significantly less sensitive, and frequencies of 16-20 kHz or higher are inaudible. However, the typical fan blades of axial fans in blower blade machines typically operate at frequencies between 2.5-4 kHz, which falls precisely within the range of human hearing sensitivity.

[0007] Therefore, there is a need in the art for improved blower / vacuum device tools. In particular, blower / vacuum device tools with reduced fan blade noise would be advantageous. Utility Model Content

[0008] The aspects and advantages of this disclosure will be set forth in part in the description which follows, or may be apparent from the description, or may be learned by practicing the technique.

[0009] According to one embodiment, a blower / vacuum device tool is provided. The blower / vacuum device tool includes a body extending between a first end and a second end, the body defining an airflow duct therethrough; and a fan assembly disposed between the first end and the second end. b An axial fan and a motor rotatably connected to the axial fan. When n b Within the range of 17-45°, the blade density of the axial fan is 0.0464 nm. b ≤Leaf density≤0.089n b Within a certain range, the blade density is calculated using the equation blade density = c / s, where c is the chord length of the fan blade, and s = 2πr. m / n b r m It is the average radius of the fan blades.

[0010] According to another embodiment, a blower / vacuum device tool is provided. The blower / vacuum device tool includes a body extending between a first end and a second end, defining an airflow duct therethrough; and a fan assembly disposed between the first end and the second end. The fan assembly includes a plurality of fan blades (n b An axial fan and a motor rotatably connected to the axial fan. When the motor operates at a speed between 21,000 and 38,000 revolutions per minute (RPM), the blade pass frequency (BPF) of the fan assembly is greater than 6 kHz, which is determined by the equation... limited.

[0011] These and other features, aspects, and advantages of this disclosure will be better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the technology and, together with the description, serve to explain the principles of the technology. Attached Figure Description

[0012] The specification sets forth a complete and practicable disclosure of this application for those skilled in the art, including the best mode of making and using the system and method. Reference is made to the accompanying drawings, in which:

[0013] Figure 1 This is a side view of a blower / vacuum device tool according to an embodiment of the present disclosure;

[0014] Figure 2 This is a side sectional view of a blower / vacuum device tool according to an embodiment of the present disclosure;

[0015] Figure 3 This is a perspective view of an axial fan according to an embodiment of the present disclosure;

[0016] Figure 4 This is a perspective view of an axial fan with an outer ring according to an embodiment of the present disclosure; and

[0017] Figure 5 This is a graphical representation of the blade solidity of an axial fan relative to the number of fan blades according to an embodiment of the present disclosure. Detailed Implementation

[0018] Reference will now be made in detail to embodiments of the present invention, one or more of which are illustrated in the accompanying drawings. The term “exemplary” as used herein means “as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or superior to other implementations. Furthermore, each example is provided by way of explanation rather than limitation. In fact, those skilled in the art will understand that modifications and variations can be made to the present invention without departing from the scope or spirit of the claimed technology. For example, a feature shown or described as part of one embodiment may be used with another embodiment to produce yet another embodiment. Therefore, this disclosure is intended to cover such modifications and variations within the scope of the appended claims and their equivalents. Detailed description uses numerical and alphabetic names to refer to features in the drawings. The same or similar names in the drawings and description have been used to refer to the same or similar parts of the present invention.

[0019] As used herein, the terms “first,” “second,” and “third” are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of the components. Unless the context clearly specifies otherwise, the singular forms “a,” “an,” and “the” include plural references. Unless otherwise specified herein, the terms “connected,” “fixed,” “attached,” etc., refer both to a direct connection, fixation, or attachment, and to an indirect connection, fixation, or attachment via one or more intermediate components or features. As used herein, the terms “comprising,” “including,” “containing,” “having,” “owning,” or any other variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, article, or apparatus that includes a list of features is not necessarily limited to those features but may include other features not expressly listed or inherent in such a process, method, article, or apparatus. Furthermore, unless otherwise expressly stated, “or” means inclusive or, not exclusive or. For example, condition A or B is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), and both A and B are true (or exist).

[0020] Approximate terms, such as "approximately," "roughly," "approximately," or "substantially," include values ​​that are within 10% larger or smaller than the stated value. When used in the context of angles or directions, these terms include values ​​that are within 10 degrees larger or smaller than the stated angle or direction. For example, "approximately vertical" includes any direction (e.g., clockwise or counterclockwise) that is within 10 degrees vertical.

[0021] The benefits, other advantages, and solutions to problems will be described below with reference to specific embodiments. However, the benefits, advantages, solutions to problems, and any features that may lead to or make more apparent any benefit, advantage, or solution should not be construed as key, necessary, or essential features of any or all claims.

[0022] In general, this utility model relates to a blower / vacuum device tool with a fan assembly that generates reduced noise during operation. The fan assembly includes an axial fan and a motor. The axial fan includes the number and size of the fan blades, as well as the operating characteristics of the motor, including the rotational speed, all optimized to reduce audible noise generated within the human hearing sensitivity range (i.e., approximately 2-6 kHz) by increasing the frequency of the fan assembly blades to a frequency greater than 6 kHz.

[0023] Now refer to the attached diagram, Figure 1 A side view of a blower / vacuum device tool 100 according to an exemplary embodiment is shown. The blower / vacuum device tool 100 is configured to generate airflow along an airflow duct 106 extending between a first end 102 (e.g., an air inlet) and a second end 104 (e.g., an air outlet) of the blower / vacuum device tool 100. The airflow duct 106 may include a pipe as shown in the figure.

[0024] like Figure 1 and Figure 2As shown, housing 108 (e.g., the body of blower / vacuum device tool 100) may at least partially enclose components of blower / vacuum device tool 100 (e.g., an airflow generating assembly 110 including a fan 112 and a motor 114 driving the fan 112) and various other components. For example, airflow generating assembly 110 may be disposed between a first end 102 and a second end 104 of airflow duct 106. Power for operating airflow generating assembly 110 may be provided by a suitable power source, such as one or more batteries 116 detachably connected to housing 108. Blower / vacuum device tool 100 may be configured as a standard handheld blower / vacuum device tool with a wireless battery-powered power supply. In other embodiments, blower / vacuum device tool may include a wired power supply and / or a gas-powered power supply. Furthermore, the blower / vacuum device tool according to this disclosure may be a handheld blower / vacuum device tool as shown, or may be configured as a backpack-type blower / vacuum device tool (not shown) suitable for wearing on the user's back.

[0025] In an exemplary embodiment, the blower / vacuum device tool may be a blower utilizing a blowing function, for example, generating airflow from a first end 102 as an inlet to a second end 104 as an outlet. In other exemplary embodiments, the blower / vacuum device tool may be a vacuum device utilizing a suction function, for example, generating airflow from a second end 104 as an inlet to a first end 102 as an outlet. In other exemplary embodiments, the blower / vacuum device tool may be a combined blower / vacuum device that can alternate between utilizing a blowing function and utilizing a suction function.

[0026] Still referencing Figure 1 and Figure 2 The airflow generating assembly 110 may have an axial configuration, including an axial fan 112. A motor 114 may be mounted within a housing 108. For example, the housing 108 may include a motor bracket 118 configured to support the motor 114 between a first end 102 and a second end 104. The motor 114 is oriented along a motor axis 120. The motor axis 120 coincides with the longitudinal axis 124 of the airflow duct. Rotation of the motor 114 causes rotation of a main motor shaft 122 extending along the motor axis 120. The motor shaft 122 is coupled to the fan 112, for example, rotatably connected to the fan 112. In this way, rotation of the motor shaft 122 causes rotation of the fan 112. The motor 114 may be configured to operate at speeds ranging from approximately 21,000 revolutions per minute (RPM) to approximately 38,000 RPM.

[0027] The fan 112 includes a hub 130 and a plurality of blades 132. The hub 130 may have a generally circular cross-sectional shape and may extend along the motor axis 120. The motor shaft 122 is coupled to the hub 130 and / or the fan drive shaft 134 so that rotation can be transmitted from the motor 114 to the hub 130 or the fan drive shaft 134 and ultimately to the blades 132.

[0028] like Figure 3 and Figure 4 As shown, each corresponding fan blade 132 extends radially away from the hub 130. Each blade 132 extends from a root 140 and terminates at a tip 142, and has a first face 144 and a second face 146 opposite to the first face 144. The root 140 contacts the hub 130 of the fan 112. The tip 142 contacts the hub 130 around its circumference at an angular position different from that of the root 140. In another embodiment (not shown), the tip 142 may contact an adjacent blade 132 of the fan 112.

[0029] like Figure 3 and Figure 4 As shown, the fan 112 may have an inner radius r defined by the radius of the hub 130. h and the outer radius r defined by the fan radius at the tip 142 of the blade. t Fan 112 may include any suitable number of fan blades (also referred to herein as n). b (as further described below).

[0030] Figure 4 An embodiment of fan 112 is shown, which may include an outer ring 150 surrounding fan blades 132. For example, the outer ring 150 may contact the ends 142 of one or more fan blades 132 (e.g., all fan blades 132). In this way, the outer ring 150 may rotate with the rotation of axial fan 112 and motor 114 during operation of blower / vacuum device tool 100.

[0031] In some aspects of this utility model, for example, Figure 2 As roughly shown in the figure, the outer ring 150 can have a value equal to 2r. t The inner diameter 152 can be approximately equal to the inner diameter of the first end 102 and / or the inner diameter of the second end 104. For example, the inner diameter 152 can be approximately equal to the inner diameter of the first end 102 and the inner diameter of the second end 104. Furthermore, the longitudinal axis 124 can extend through the center point of the first end 102, the center point of the outer ring 150, and the center point of the second end 104. In this way, the airflow duct can have a diameter that is approximately constant along the length of the airflow duct 106, thereby reducing interference with the flow within the airflow duct.

[0032] The inventors have discovered that the passing frequency of the blades of the blower / vacuum device tool 100 can correspond to the sound frequency generated by the axial fan of the tool 100. The passing frequency of the blades can be calculated using the following equation: In this respect, the number of blades (also referred to as n in this paper) b The speed of the fan and the blower directly affect the sound frequency generated by the blower / vacuum device tool 100. Since human hearing is most sensitive to sound frequencies between 2-6 kHz, and hearing sensitivity decreases and / or weakens above 6 kHz, the inventors have discovered that achieving a higher blade pass frequency can thus reduce the audible noise generated by the blower / vacuum device tool 100. Based on the provided equations, the inventors have discovered that to achieve a higher blade pass frequency above 6 kHz and thus reduce the generated audible noise, the motor speed can be increased, the number of fan blades 132 can be increased, or both the motor speed and the number of fan blades 132 can be increased simultaneously.

[0033] In the blower / vacuum device tool 100 of this invention, as described above, the motor can be configured to rotate at a speed between approximately 21,000 and 38,000 RPM. Since human hearing is most sensitive to sound frequencies between 2 and 6 kHz, the inventors have found that it may be ideal to provide a blower / vacuum device tool 100 with blades passing through frequencies greater than 6 kHz. Therefore, when the blower / vacuum device tool 100 may operate at motor speeds as low as 21,000 RPM, the inventors have found that implementing a fan 112 having at least 17 fan blades 132 may be ideal.

[0034] Furthermore, it may be desirable to increase the number of fan blades 132 provided on fan 112. Blade density is a measure of fan blade spacing, which is directly affected by the number of blades provided on a given fan. Blade density is defined by the following equation: Blade density = c / s, where s = 2πr m / n b In this equation, c is the length of the chord of the fan blade, and the shank is the average radius of the fan blade. The average radius r of the fan blade... m From the equation The calculation yielded the result.

[0035] The inventors have discovered that increasing the number of blades to increase the blade density of the fan 112 can reduce the audible noise generated by the blower / vacuum device tool 100 during operation. Furthermore, as the number of blades n increases... b With the increase of [something], the blade density value may also increase. The inventors have discovered that ideal noise reduction can be achieved when the fan 112 of the blower / vacuum device tool 100 meets the following conditions: n b Within the range of 17 to 45, the blade density of the axial fan 112 can reach 0.0464 nm.b ≤Leaf density≤0.089n b Within the range.

[0036] The inventors have discovered that the airflow generating assembly 110 with an axial fan 112 of this invention can be optimized when the dimensionless flow coefficient Φ is in the range of about 0.2 to about 0.6. The size and velocity of the airflow generating assembly 110 are defined as a function of the optimal flow coefficient Φ. The flow coefficient is calculated using the following equation:

[0037]

[0038] Where q represents flow rate (m 3 / s), A represents the cross-sectional area of ​​the fan (m²). 2 ), where ω represents the velocity (rad / s), and R represents the fan tip radius (m) measured at 142° from the blade tip. In other words, the numerator q / (A) is the axial velocity of the fan (m / s).

[0039] Based on the calculation of the flow coefficient Φ shown above, the optimal fan size can be determined by rearranging the equations as shown below:

[0040]

[0041] By optimizing the blade density and flow coefficient of the airflow generation component 110 during operation of the blower / vacuum device tool 100, the inventors have discovered that the blower / vacuum device tool 100 can generate less audible noise while maintaining optimal airflow characteristics, thereby improving the overall user experience during operation. For example, reducing the audible noise generated by the blower / vacuum device tool 100 can be very beneficial to users, especially homeowners and other non-professional users. Simultaneously, maintaining optimal airflow characteristics allows for effective battery life of the blower / vacuum device tool 100, reducing the need for users to charge or replace the power source without reducing the airflow power generated during operation.

[0042] To further reduce audible noise generated during operation of the blower / vacuum device tool 100, the housing 108 may include an inlet silencer 160 disposed at a first end 102. For example, the inlet silencer 160 may be disposed within an airflow duct 106 at the first end 102. In some embodiments, the inlet silencer 160 may include a bushing 162 surrounding at least a portion of the airflow duct 106. The bushing 162 may include a sound-absorbing material. In particular, the sound-absorbing material may be configured to absorb noise in the 2-6 kHz frequency range to reduce audible noise in the human hearing frequency range. The sound-absorbing material may include foam. Alternatively or additionally, the sound-absorbing material may include foam, such as, but not limited to, foam / film laminates, such as polyurethane foam. The bushing 162 may surround the entire circumference of the air duct 106 and / or one or more portions of the circumference of the air duct 106.

[0043] Further aspects of this disclosure are provided by one or more of the following embodiments:

[0044] A blower / vacuum device tool includes a body extending between a first end and a second end, the body defining an airflow duct therethrough; and a fan assembly. The fan assembly includes a plurality of fan blades (n b The fan consists of an axial flow fan and a motor rotatably connected to the fan. When the motor operates at a speed between 21,000 and 38,000 revolutions per minute (RPM), the blade pass frequency (BPF) of the fan assembly is greater than 6 kHz, which is determined by the equation... limited.

[0045] The blower / vacuum device tool in any one or more embodiments, wherein the plurality of fan blades includes 17 to 45 fan blades.

[0046] Blower / vacuum device tool of any one or more embodiments, wherein the axial fan includes a hub and a plurality of fan blades extend from the hub at the root of each respective fan blade.

[0047] The blower / vacuum device tool of any one or more embodiments, wherein each of the plurality of fan blades terminates at the end of each respective fan blade, and the axial fan further includes an outer ring that contacts the end of each respective fan blade.

[0048] Blower / vacuum device tool of any one or more embodiments, wherein the outer ring rotates as the axial fan rotates.

[0049] A blower / vacuum device tool of any one or more embodiments, wherein the outer ring includes an inner diameter, wherein the inner diameter of the outer ring is approximately equal to the inner diameter of the first end and / or the inner diameter of the second end.

[0050] A blower / vacuum device tool of any one or more embodiments, wherein a longitudinal axis extends through the center point of a first end of the body, the center point of an outer ring, and the center point of a second end of the body.

[0051] The blower / vacuum device tool of any one or more embodiments further includes an inlet silencer disposed at a first end of the body, the inlet silencer including a bushing including sound-absorbing material configured to absorb noise in the frequency range of 2-6 kHz.

[0052] Blower / vacuum device tools of any one or more embodiments, wherein the sound-absorbing material includes foam.

[0053] In any one or more embodiments of the blower / vacuum device tool, wherein when the motor operates at a speed between 21,000 and 38,000 revolutions per minute (RPM), the fan assembly has a characteristic defined by the equation The calculated dimensionless flow coefficient Φ, ranging from approximately 0.3 to 0.5, is given, where q represents the flow rate (m³ / s). 3 / s), A represents the cross-sectional area at the fan (m²). 2 ), where ω represents the velocity (rad / s) and R represents the fan tip radius (m) measured at the blade tip.

[0054] A blower / vacuum device tool includes a body extending between a first end and a second end, defining an airflow duct therethrough; and a fan assembly. The fan assembly includes a plurality of fan blades (n b An axial fan and a motor rotatably connected to the fan. When n b Within the range of 17-45°, the blade density of the axial fan is 0.0464 nm. b ≤Leaf density≤0.089n b Within this range, the blade density is calculated using the equation blade density = c / s, where c is the length of the chord of the fan blade, and s = 2πr. m / n b r m It is the average radius of the fan blades. In any one or more embodiments of the blower / vacuum device tool, the axial fan includes a hub, and each of the fan blades extends from the hub at the root of each respective fan blade.

[0055] The blower / vacuum device tool in any or more embodiments, wherein each fan blade terminates at the end of each respective fan blade, and the axial fan further includes an outer ring that contacts the end of each respective fan blade.

[0056] The blower / vacuum device tool in any one or more embodiments, wherein the outer ring rotates with the rotation of the axial fan.

[0057] A blower / vacuum device tool of any one or more embodiments, wherein the outer ring includes an inner diameter, wherein the inner diameter of the outer ring is approximately equal to the inner diameter of the first end and / or the inner diameter of the second end.

[0058] A blower / vacuum device tool of any one or more embodiments, wherein a longitudinal axis extends through the center point of a first end of the body, the center point of an outer ring, and the center point of a second end of the body.

[0059] The blower / vacuum device tool of any one or more embodiments further includes an inlet silencer disposed at a first end of the body, the inlet silencer including a bushing comprising sound-absorbing material configured to absorb noise in the 2-6 kHz frequency range.

[0060] Blower / vacuum device tools of any one or more embodiments, wherein the sound-absorbing material includes foam.

[0061] In any one or more embodiments of the blower / vacuum device tool, wherein when the motor operates at a speed between 21,000 and 38,000 revolutions per minute (RPM), the fan assembly has a characteristic defined by the equation The calculated dimensionless flow coefficient Φ, ranging from approximately 0.3 to 0.5, is given, where q represents the flow rate (m³ / s). 3 / s), A represents the cross-sectional area at the fan (m²). 2 ), where ω represents the velocity (rad / s) and R represents the fan tip radius (m) measured at the blade tip.

[0062] This written description uses examples to disclose the present invention, including the best mode of implementation, and also enables those skilled in the art to practice the present invention, including making and using any device or system and performing any combined methods. The patentable scope of the present invention is defined by the claims, but may include other examples that would occur to those skilled in the art. Such other examples are intended to fall within the scope of the claims if they include structural elements that are not different from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims.

[0063] The present invention provides the following embodiments:

[0064] Embodiment 1. A blower / vacuum device tool, characterized in that the blower / vacuum device tool comprises:

[0065] A body defining an airflow duct therethrough, the body extending between a first end and a second end; and

[0066] A fan assembly disposed between the first end and the second end, the fan assembly including an axial fan having a plurality of fan blades and a motor rotatably connected to the axial fan;

[0067] When the motor operates at a speed between 21,000 and 38,000 revolutions per minute (RPM), the blade pass frequency (BPF) of the fan assembly is greater than 6 kHz, and the blade pass frequency is determined by the equation... limited.

[0068] Embodiment 2. The blower / vacuum device tool according to Embodiment 1, characterized in that the plurality of fan blades comprises 17 to 45 fan blades.

[0069] Embodiment 3. The blower / vacuum device tool according to Embodiment 1, characterized in that the axial fan includes a hub, and the plurality of fan blades extend from the hub at the root of each respective fan blade.

[0070] Embodiment 4. The blower / vacuum device tool according to Embodiment 3, characterized in that each of the plurality of fan blades terminates at the end of each corresponding fan blade, and the axial fan further includes an outer ring that contacts the end of each corresponding fan blade.

[0071] Embodiment 5. The blower / vacuum device tool according to Embodiment 4, characterized in that the outer ring rotates with the rotation of the axial fan.

[0072] Embodiment 6. The blower / vacuum device tool according to Embodiment 4, characterized in that the outer ring includes an inner diameter, wherein the inner diameter of the outer ring is equal to the inner diameter of the first end and / or the inner diameter of the second end.

[0073] Embodiment 7. The blower / vacuum device tool according to Embodiment 4, characterized in that the longitudinal axis extends through the center point of the first end of the body, the center point of the outer ring, and the center point of the second end of the body.

[0074] Embodiment 8. The blower / vacuum device tool according to Embodiment 1, characterized in that the blower / vacuum device tool further includes an inlet silencer disposed at the first end of the main body, the inlet silencer including a bushing, the bushing including a sound-absorbing material configured to absorb noise in the frequency range of 2-6KHz.

[0075] Embodiment 9. The blower / vacuum device tool according to Embodiment 8, characterized in that the sound-absorbing material comprises foam.

[0076] Embodiment 10. The blower / vacuum device tool according to Embodiment 1, characterized in that, when the motor operates at a speed of 21,000-38,000 RPM, the fan assembly has the property of... (The sentence is incomplete and requires further context to translate accurately.) The calculated dimensionless flow coefficient Φ, ranging from 0.3 to 0.5, is given, where q represents the unit in m³. 3 The flow rate is / s, where A represents the unit at the fan location as m³ / s. 2 The cross-sectional area, ω represents the velocity in rad / s, and R represents the fan tip radius in meters, measured at the blade tip.

[0077] Embodiment 11. A blower / vacuum device tool, characterized in that the blower / vacuum device tool comprises:

[0078] A body defining an airflow duct therethrough, the body extending between a first end and a second end; and

[0079] A fan assembly disposed between the first end and the second end, wherein the fan assembly includes a number of n... b An axial fan with multiple fan blades and a motor that is rotatably connected to the axial fan;

[0080] Where, when n b Within the range of 17 to 45, the blade density of the axial fan is 0.0464 nm. b ≤Leaf density≤0.089n b Within the specified range, the blade density is calculated using the equation blade density = c / s, where c is the length of the chord of the fan blade, and s = 2πr. m / n b r m It is the average radius of the fan blades.

[0081] Embodiment 12. The blower / vacuum device tool according to Embodiment 11, characterized in that the axial fan includes a hub, and each of the fan blades extends from the hub at the root of each respective fan blade.

[0082] Embodiment 13. The blower / vacuum device tool according to Embodiment 12, characterized in that each of the fan blades terminates at the end of each corresponding fan blade, and the axial fan further includes an outer ring that contacts the end of each corresponding fan blade.

[0083] Embodiment 14. The blower / vacuum device tool according to Embodiment 13, characterized in that the outer ring rotates with the rotation of the axial fan.

[0084] Embodiment 15. The blower / vacuum device tool according to Embodiment 13, characterized in that the outer ring includes an inner diameter, wherein the inner diameter of the outer ring is equal to the inner diameter of the first end and / or the inner diameter of the second end.

[0085] Embodiment 16. The blower / vacuum device tool according to Embodiment 13, characterized in that the longitudinal axis extends through the center point of the first end of the body, the center point of the outer ring, and the center point of the second end of the body.

[0086] Embodiment 17. The blower / vacuum device tool according to Embodiment 11, characterized in that the blower / vacuum device tool further includes an inlet silencer disposed at the first end of the main body, the inlet silencer including a bushing, the bushing including a sound-absorbing material configured to absorb noise in the frequency range of 2-6KHz.

[0087] Embodiment 18. The blower / vacuum device tool according to Embodiment 17, characterized in that the sound-absorbing material comprises foam.

[0088] Embodiment 19. The blower / vacuum device tool according to Embodiment 11, characterized in that, when the motor operates at a speed of 21,000-38,000 RPM, the fan assembly has the property of... (The sentence is incomplete and requires further context to translate accurately.) The calculated dimensionless flow coefficient Φ, ranging from 0.3 to 0.5, is given, where q represents the unit in m³. 3 The flow rate is / s, where A represents the unit at the fan location as m³ / s. 2 The cross-sectional area, ω represents the velocity in rad / s, and R represents the fan tip radius in meters, measured at the blade tip.

Claims

1. A blower / vacuum device tool, characterized in that, The blower / vacuum device tool includes: A body defining an airflow duct therethrough, the body extending between a first end and a second end; and A fan assembly disposed between the first end and the second end, wherein the fan assembly includes a number of n... b An axial fan with multiple fan blades and a motor that is rotatably connected to the axial fan; Where, when n b Within the range of 17 to 45, the blade density of the axial fan is 0.0464 nm. b ≤Leaf density≤0.089n b Within the specified range, the blade density is calculated using the equation blade density = c / s, where c is the length of the chord of the fan blade, and s = 2πr. m / n b r m It is the average radius of the fan blades.

2. The blower / vacuum device tool according to claim 1, characterized in that, The axial fan includes a hub, and each of the fan blades extends from the hub at the root of each respective fan blade.

3. The blower / vacuum device tool according to claim 2, characterized in that, Each of the fan blades terminates at the end of each corresponding fan blade, and the axial fan also includes an outer ring that contacts the end of each corresponding fan blade.

4. The blower / vacuum device tool according to claim 3, characterized in that, The outer ring rotates as the axial fan rotates.

5. The blower / vacuum device tool according to claim 3, characterized in that, The outer ring includes an inner diameter, wherein the inner diameter of the outer ring is equal to the inner diameter of the first end and / or the inner diameter of the second end.

6. The blower / vacuum device tool according to claim 3, characterized in that, The longitudinal axis extends through the center point of the first end of the body, the center point of the outer ring, and the center point of the second end of the body.

7. The blower / vacuum device tool according to claim 1, characterized in that, The blower / vacuum device tool also includes an inlet silencer disposed at the first end of the main body, the inlet silencer including a bushing including sound-absorbing material configured to absorb noise in the 2-6KHz frequency range.

8. The blower / vacuum device tool according to claim 7, characterized in that, The sound-absorbing material includes foam.

9. The blower / vacuum device tool according to claim 1, characterized in that, When the motor operates at a speed between 21,000 and 38,000 revolutions per minute (RPM), the fan assembly has the property of... (The sentence is incomplete and requires more context to translate accurately.) The calculated dimensionless flow coefficient Φ, ranging from 0.3 to 0.5, is given, where q represents the unit in m³. 3 The flow rate is / s, where A represents the unit at the fan location as m³ / s. 2 The cross-sectional area, ω represents the velocity in rad / s, and R represents the fan tip radius in meters, measured at the blade tip.

Images