Electric tool

Abstract

The utility model discloses an electric tool. The electric tool comprises a main body and a handheld component arranged at the top of the main body, wherein the main body comprises a host shell; the motor, the cutter and the one or more resonant cavities are arranged in the internal space of the main machine shell; wherein the resonant cavity is configured to partially surround the cutter and the motor, and comprises a cavity shell and one or more air inlets formed in the cavity shell; wherein the air inlet is in fluid communication with the interior of the cavity shell; wherein one side face of the air inlet faces the internal space, and the other side face faces the interior of the cavity shell.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power tools, in particular to a power tool comprising a noise reduction device. BACKGROUND

[0002] As a type of power tool, a power planer is used in the woodworking industry to level the surface of wood. A power planer generates a lot of noise when it is working. This noise is mainly caused by the high-speed rotation of the cutter head, the strong ejection of wood chips, the operation of the motor, and the vibration between the cutter head and the surface of the wood. These factors combine to create an uncomfortable experience for the user and people nearby. Active noise reduction devices are usually expensive and can affect the portability and operational flexibility of the tool.

[0003] A Helmholtz-type resonator is a sound-absorbing device composed of a rigid cavity and a through-hole provided on the shell of the cavity to allow the inside of the cavity to communicate with the external medium (usually air) through the through-hole. The fluid in the cavity is similar to a mechanical mass element. The pressure in the cavity changes with the inflow and outflow of the fluid through the through-hole. This makes the cavity similar to a spring element in some ways, dissipating energy through vibration, thereby acting as a damper. This technology has typical applications in the automotive field (such as tires) and compressors.

[0004] Combining a Helmholtz-type resonator with a power tool that generates a lot of noise during operation provides new possibilities for noise reduction of power tools. INVENTION CONTENTS

[0005] To solve the problem of noise of power tools, the present application proposes a power tool related to a Helmholtz-type resonator. Integrating a Helmholtz-type resonator into the design of a power tool has multiple advantages. By tuning the resonator to the main noise frequency generated by the power tool, specific noise components can be attenuated. Unlike active noise cancellation systems, the Helmholtz-type resonator does not require an input power source, thereby maintaining the portability of the power tool. This resonator can be integrated into existing cavities within the structure of the power tool, minimizing additional volume, and because there are no moving parts, the resonator system is very robust and virtually maintenance-free.

[0006] The present application proposes a power tool, comprising: a main body and a hand-held component arranged on the top of the main body; wherein the main body comprises: a main housing; a motor, a cutter and one or more resonant cavities arranged in the internal space of the main housing; wherein the resonant cavity is configured to partially surround the cutter and the motor, and comprises a cavity shell and one or more air inlets arranged on the cavity shell; wherein the air inlets are in fluid communication with the inside of the cavity shell; wherein one side of the air inlets faces the internal space, and the other side faces the inside of the cavity shell.

[0007] According to an optional embodiment, the power tool further comprises: a chip outlet arranged at one side or both sides of the main housing; a bottom plate arranged at the bottom of the main housing; wherein the bottom plate is provided with an opening in the middle for selectively extending a part of the tool; wherein the chip outlet is communicated to the internal space; wherein the chip outlet, the internal space and the opening define a gas flow path through which the gas flows in the power tool after entering the power tool via the opening and before being discharged from the power tool via the chip outlet.

[0008] According to an optional embodiment, the resonant cavity is arranged in the gas flow path.

[0009] According to an optional embodiment, the cavity shell and the gas inlet are sized so that the natural frequency of the resonant cavity matches the air vibration frequency in the internal space.

[0010] According to an optional embodiment, the resonant cavity comprises one or more partition walls to divide the cavity shell into a plurality of sub-cavities; each sub-cavity is communicated to one or more gas inlets.

[0011] According to an optional embodiment, each partition wall extends in a plane parallel to the axial and longitudinal directions, and / or extends in a plane parallel to the transverse and longitudinal directions, and / or extends in a plane parallel to the transverse and axial directions.

[0012] According to an optional embodiment, each partition wall extends radially around the axial direction, and / or the transverse direction or and / or the longitudinal direction.

[0013] According to an optional embodiment, each partition wall has a non-planar curved shape.

[0014] According to an optional embodiment, the partition walls adjacent to each other are connected to each other to form a grid-like sub-cavity arrangement.

[0015] According to an optional embodiment, the wall thickness of the cavity shell at the gas inlet is increased or thinned.

[0016] Compared with the prior art, the power tool according to the present application has the following technical effects. The noise reduction device based on the Helmholtz resonator has effectiveness, high efficiency and practicality. As a passive system, the Helmholtz resonator utilizes the existing cavity in the power tool structure to achieve target frequency attenuation, avoiding the increase of the size or weight of the power tool. Multiple frequencies generated in the power tool can be processed by different tuning cavities, achieving comprehensive noise reduction without affecting the function. Unlike active noise reduction systems or expensive silent motors, this cost-effective solution does not require power input or maintenance, thus maintaining the portability and reliability of the power tool. The power tool according to the present application improves the comfort and safety of the user by significantly reducing the operating noise. BRIEF DESCRIPTION OF DRAWINGS

[0017] The disclosure of the present application will become more fully understood from the detailed description, taken in conjunction with the accompanying drawings. It is readily understood that these drawings are not limiting of the scope of the present application, and are merely intended to be illustrative. The same reference numbers in different drawings represent the same components.

[0018] Figure 1 is a perspective view of an electric power tool according to the present application;

[0019] Figure 2 is a side view of the electric power tool of Figure 1 ; and

[0020] Figure 3 is a partial cross-sectional top view of the electric power tool of Figure 1 ; and

[0021] Figure 4 is a perspective view of a resonant cavity of the electric power tool of Figure 1 ; and

[0022] The same reference numbers in different drawings represent the same components. DETAILED DESCRIPTION

[0023] Example embodiments of the present application will now be described in detail with reference to the accompanying drawings. Although example embodiments of the present application are shown in the drawings as electric planers, it should be understood that the present application can be implemented in various other forms, and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the application to those skilled in the art.

[0024] Figure 1 is a perspective view of an electric power tool according to the present application. Figure 2 is a side view of the electric power tool of Figure 1 . As shown in Figure 1 and Figure 2 , the electric power tool generally includes a main body 10 and a hand-held member 9 provided on top of the main body 10. The main body 10 can include a main housing 11, chip outlets 3 (both sides in the drawings) provided on one or both sides of the main housing 11, a planer depth scale 1 provided on the main housing 11, a scale setting knob 2 provided at the center of the planer depth scale 1, a motor 14 and a cutter (see Figure 3 ) provided in the main housing 11, a transmission device (not shown) provided on the side of the main housing 11, a rotation device cover 7 provided outside the transmission device, electrical elements provided in the main housing 11 and a related support structure supporting the electrical elements, a power cord 6 for connecting to an external power source (e.g., an external AC or DC power source) to supply power to the motor 14, and a bottom plate 20 provided on the bottom of the main housing 11.

[0025] The configuration and structure of the motor 14 and electrical components inside the main housing 11 are not the focus of the present application and are not described in detail herein. The present application is not limited to power tools that use an external power source to power the motor 14, and it is possible for the power tool to include a battery pack for powering the motor 14. The depth scale knob 2 and the depth dial 1 cooperate to modify the depth of the tool bit of the power tool. A transmission is used to transmit the power of the motor 14 to the tool bit, which is rotatably fixed in the main housing 11. In the illustrated embodiment, the transmission can include a driving pulley fixed on the motor 14, a driven pulley fixed on the tool bit, and a belt wrapped around the driving pulley and the driven pulley. The base plate 20 is provided with an opening in the middle for allowing a portion of the tool bit to be selectively extended out.

[0026] The main housing 11 and the hand grip member 9 can be integrally formed, or can be separate components that are formed separately and then attached together. The main housing 11 has an outer shape structure that is suitable for being held by an operator to operate the power tool. Optionally, the hand grip member 9 includes a feature for increasing the friction between the hand and the housing when the hand grip member 9 is held by the hand of the operator. The feature can include a piece of plastic or rubber material attached to the outer surface of the hand grip member 9, and optionally or additionally, the feature can also include a convex and / or concave portion formed on the outer surface of the hand grip member 9. One or both of the main housing 11 and the hand grip member 9 can be attached from two halves that face each other.

[0027] The start-stop switch lock button 4 and the start-stop switch 5 are respectively provided on the hand grip member 9 at positions that are convenient for the operator to operate (e.g. press) when the operator is holding the hand grip member 9 for operation, e.g. as illustrated in the positions that are convenient for the operator's right hand index finger (corresponding to the start-stop switch 5) and thumb (corresponding to the start-stop switch lock button 4) to operate when the right hand is holding the hand grip member 9. In the illustrated embodiment, the start-stop switch lock button 4 and the start-stop switch 5 are respectively provided on the side and bottom of the hand grip member 9. The start-stop switch lock button 4 is used to lock the start-stop switch 5. The start-stop switch lock button 4 remains pressed after it is pressed, until it is pressed again. When the start-stop switch lock button 4 is in the pressed state, the start-stop switch 5 is locked and cannot change state. In this way, the start-stop switch lock button 4 can ensure that the start-stop switch 5 is not inadvertently pressed when the start-stop switch 5 is not pressed, and can maintain the pressed state of the start-stop switch 5 after the start-stop switch 5 has been pressed, without the need to continuously press the start-stop switch 5, ensuring that the operation of the power tool is not inadvertently interrupted.

[0028] The main housing 11 defines an interior space that houses the motor 14 and the tool. The motor 14 includes primarily a motor shaft, and a motor rotor and a motor stator disposed radially outwardly around the motor shaft. The main housing 11 also defines a component space in communication with the motor space for housing various electrical components required for operation of the power tool. These electrical components include a controller for controlling the motor 14, controls or electrical components for controlling operation of the power tool, various switches, etc., which can be mounted on one or more circuit boards. The chip outlet 3 communicates to the interior space for discharging chips brought into the interior space by the tool during operation of the power tool.

[0029] Figure 3 is a partial cutaway top view of the power tool of Figure 1 , with a portion of the parts omitted. As shown in Figure 2 and Figure 3 , in this application, the direction in which the motor shaft extends is defined as the axial direction A, the direction perpendicular to the axial direction A in the horizontal plane is defined as the transverse direction T, and the direction perpendicular to both the axial direction A and the transverse direction T is defined as the longitudinal direction L. The motor shaft has a central axis or rotation axis extending in the axial direction A and is rotatable about it. The tool likewise has a central axis or rotation axis extending in the axial direction A and is rotatable about it. For the sake of convenience in description, this application also defines the directional terms "front" and "rear" in the transverse direction T and the directional terms "upper" and "lower" in the longitudinal direction L. In the transverse direction T, the tool is located in front of the motor 14, and the scale setting knob 2 and the depth scale 1 are located in front of the tool. The base plate 20 is provided with a V-shaped groove 16 (see Figure 1 ) at the front edge for maintaining its position at a certain angle of inclination (e.g., 45°) during operation of the power tool.

[0030] Due to the requirements of the mold and cooling, the interior space is usually irregular. These interior spaces are the basis of the Helmholtz type sound absorbers. The power tool also includes one or more resonance cavities 21 (three in this embodiment) disposed around the motor 14 and the tool in the interior space. The resonance cavities 21 can partially surround the tool and the motor 14, for example, can be disposed between the tool and the depth scale 1 in the transverse direction T, between the tool and the motor 14 in the transverse direction T, and between the motor 14 and the power cord 6 in the transverse direction T. It can be understood that the resonance cavities 21 can also be disposed at other positions, for example, above the tool in the longitudinal direction L.

[0031] Figure 4 is a perspective view of the resonance cavity of the power tool of Figure 1 . As shown in Figure 4As shown, the resonant cavity 21 includes a cavity shell 211 and an air inlet 212 disposed on the cavity shell 211. Thus, the air inlet 212 is in fluid communication with the interior of the cavity shell 211. One side of the air inlet 212 faces the interior space. The high-speed rotating cutting tool and motor 14, the forced high-speed airflow, and various frequencies of noise generated by the aforementioned and other factors all exist in this interior space. The other side of the air inlet 212 faces the interior of the cavity shell 211. The airflow caused by the cutting tool and motor 14 flows into and out of the cavity shell 211 through the air inlet 212. The inflowing and outflowing air creates a pressure difference between the interior (referred to as the chamber) and the exterior of the cavity shell 211, causing air vibration. When the sound wave frequency of the airflow in the interior space matches the air vibration frequency inside the cavity shell 211, resonance occurs, consuming the energy of the incident sound wave and achieving absorption of sound waves of a specific frequency.

[0032] In order to obtain different natural frequencies of the Helmholtz-type silencer, the parameters of the cavity shell 211 or the air inlet 212 can be appropriately changed, including but not limited to the extension direction, number, size, and arrangement of the cavity and / or the number, size, and arrangement of the air inlets 212, etc.

[0033] In the illustrated embodiment, the resonant cavity 21 further includes multiple partition walls 213 to divide the cavity housing 211 into multiple sub-cavities. Each sub-cavity communicates with one or more air inlets 212. Thus, multiple Helmholtz-type silencing devices are formed. The size of each sub-cavity and the arrangement of the corresponding air inlets 212 can be the same or different to provide Helmholtz-type silencing devices with the same or different natural frequencies, thereby eliminating noise of different frequencies.

[0034] The arrangement of the partition walls 213 can be changed to provide sub-cavities of various sizes or volumes. For example... Figure 4 As shown, each partition wall 213 can extend in a plane parallel to the axial direction A and the transverse direction T (i.e., a horizontal plane), or in a plane parallel to the transverse direction T and the longitudinal direction L (i.e., a vertical plane), or in a plane parallel to the axial direction A and the longitudinal direction L (i.e., a vertical plane in another direction). In other embodiments, each partition wall 213 can extend radially around the axial direction A, the transverse direction T, or the longitudinal direction L. The partition walls 213 can also have any non-planar curved shape. For example, each partition wall 213 can extend spirally or in other curved shapes around the axial direction A, the transverse direction T, and the longitudinal direction L. In other embodiments, adjacent partition walls 213 can be interconnected to form a grid-like sub-cavity arrangement of various shapes or sizes, provided that each sub-cavity communicates with one or more of the air inlets 212.

[0035] The air inlets 212 can be provided in different numbers and opening areas to obtain different resonance frequencies in combination with different sub-cavities. The configuration of the air inlets 212 associated with the sub-cavities can include one or more of the following: the number of each air inlet 212, the size of each air inlet 212, the arrangement of each air inlet 212 (the relative position relationship or distance between each air inlet 212, etc.), the hole depth of each air inlet 212, and the like. The hole depth of the air inlet 212 depends on the wall thickness of the part of the cavity shell 211 in which the air inlet 212 is located. In order to obtain different hole depths of the air inlets 212, the wall thickness of this part of the cavity shell 211 can be locally increased or thinned.

[0036] The basic principles of the present application are described above with respect to the illustrated example of the electric power tool. The present application only adds the resonant cavity 21 in the internal space without the need to significantly modify the structure of the electric power tool, i.e. obtains the technical effect of creating a sound elimination device to eliminate noise while not affecting the heat dissipation function.

[0037] Those skilled in the art will understand after reading the above description that the principles of the present application are not only applicable to electric planers, but also to any electric power tool containing a motor, a rotating cutter and a transmission device. The principles of the present application are not only applicable to electric power tools in which the motor shaft and the cutter shaft are arranged in parallel, but also to electric power tools in which the motor shaft and the cutter shaft are arranged vertically or obliquely. The principles of the present application are applicable to cases where the transmission device includes a belt pulley and a belt, and also to cases where the transmission device includes a plurality of gears meshing with each other.

[0038] Those skilled in the art will understand that the above detailed description of the basic principles, main features and advantages of the present application does not limit the present application in any form, and any technical solution obtained by equivalent substitution or equivalent transformation falls within the protection scope of the present application.

Claims

1. A power tool characterized by comprising: The electric power tool comprises: a main body (10) and a hand-held member (9) arranged on top of the main body (10); wherein the main body (10) comprises: a main housing (11); a motor (14), a tool and one or more resonance cavities (21) arranged in an inner space of the main housing (11); wherein the resonance cavity (21) is configured to partially enclose the tool and the motor (14), and comprises a cavity housing (211) and one or more air inlets (212) arranged on the cavity housing (211); wherein the air inlets (212) are in fluid communication with an interior of the cavity housing (211); wherein one side of the air inlets (212) faces the inner space and the other side faces the interior of the cavity housing (211).

2. The power tool of claim 1, wherein, The electric power tool comprises: a chip outlet (3) arranged on one or both sides of the main housing (11); a bottom plate (20) arranged on the bottom of the main housing (11); wherein the bottom plate (20) is provided with an opening in the middle for selectively extending a part of the tool; wherein the chip outlet (3) is in communication with the inner space; wherein the chip outlet (3), the inner space and the opening define a gas flow path through which the gas flows in the electric power tool after entering the electric power tool via the opening and before being discharged from the electric power tool via the chip outlet (3).

3. The electric power tool according to claim 2, characterized in that the resonance cavity (21) is arranged in the gas flow path.

4. The electric power tool according to claim 3, characterized in that the cavity housing (211) and the air inlets (212) are sized such that the natural frequency of the resonance cavity (21) matches the air vibration frequency in the inner space.

5. The electric power tool according to any one of claims 1-4, characterized in that the resonance cavity (21) comprises one or more partition walls (213) to divide the cavity housing (211) into a plurality of sub-cavities; each sub-cavity is in communication with one or more air inlets (212).

6. The electric power tool according to claim 5, characterized in that each partition wall (213) extends in a plane parallel to the axial direction (A) and the longitudinal direction (L), and / or in a plane parallel to the transverse direction (T) and the longitudinal direction (L), and / or in a plane parallel to the transverse direction (T) and the axial direction (A).

7. The electric power tool according to claim 5, characterized in that each partition wall (213) extends radially around the axial direction (A), and / or the transverse direction (T) or and / or the longitudinal direction (L).

8. The electric power tool according to claim 5, characterized in that each partition wall (213) has a non-planar curved shape.

9. The electric power tool according to claim 5, characterized in that adjacent partition walls (213) are connected to each other to form a grid-like sub-cavity arrangement.

10. The electric power tool according to claim 5, characterized in that the wall thickness of the cavity housing (211) is increased or thinned at the air inlets (212).

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