CN117718927A - Electric tool - Google Patents

Abstract

The application relates to a power tool, comprising: a main housing (12) that houses a motor (14) including a motor shaft (15); a fan (40) mounted on the motor shaft (15) to rotate therewith; and a wind scooper (60) disposed between the fan and the motor in an axial direction (L), comprising: an annular body (62); a front guide (72) extending axially forward from the annular body and radially outward perpendicular to the axial direction (L) to engage the main housing; and a rear portion (74) extending radially outwardly from the annular body into engagement with the main housing such that a closed chamber (85) is defined between the front guide portion (72) of the air scoop, the rear portion (74) and the main housing (12), the front guide portion defining an interior space (95) in which the fan is located and including a through bore (75) extending through the front guide portion (72) to place the interior space (95) in fluid communication with the chamber (85).

Description

Electric tool

Technical Field

The present application relates to the field of power tools, and in particular to a hand-held power tool including a motor and a cooling fan.

Background

Many hand-held power tools employ a motor as a power source to provide a driving force, and include a control circuit board provided with electrical components for controlling the operation of the power tool or controlling the operation of the motor. For example, such power tools may include angle grinders for cutting, grinding, etc. hard workpieces such as glass, metal, stone, etc.

The motor of the electric tool runs at a high speed during the operation process, the electric element is electrified to work for a long time, and a large amount of heat is generated in the electric tool. In order to timely dissipate heat generated by the motor and the electronic element so as to ensure or prolong the service lives of the motor and the circuit element and even the whole electric tool, the motor of the electric tool is provided with a fan.

The fan is mounted on the motor shaft of the motor and rotates at a high speed with the motor shaft, thereby sucking air into the power tool. The air flow passes through the motor and electrical components to remove heat and is eventually exhausted from the power tool. In this process, noises are generated by the motor rotor of the electric tool, the motor shaft and bearings rotating at high speed, the fan driven by the motor shaft to rotate at high speed, the high-speed air flow caused by the fan, the rotation of the transmission means (in particular, the gear engagement means) driven by the motor shaft, and their possible vibrations, which may cause the operator to feel uncomfortable.

Numerous studies and improvements have been made by those skilled in the art to reduce noise during operation of power tools. However, these improvements often introduce additional components or greatly alter the original structure of the power tool, complicating the structure of the power tool and increasing the cost.

Disclosure of Invention

The present invention aims to solve the noise problem with minimal or no structural modification to the power tool.

This object is achieved by the power tool of the present application. The electric tool of this application includes: a main housing a motor and defining at least one of an air inlet and an air outlet, the motor having an axially extending motor shaft; a fan mounted on the motor shaft to rotate therewith; and a wind scooper disposed between the fan and the motor in an axial direction, wherein the wind scooper includes: an annular body defining a central through bore through which air flow from the air inlet into the power tool is permitted; a front guide extending axially forward from the annular body away from the motor and radially outward perpendicular to the axial direction to engage the main housing; and a rear portion extending radially outwardly from the annular body into engagement with the main housing such that a closed chamber is defined between the front guide portion, the rear portion and the main housing of the air guide housing, wherein an inner surface of the front guide portion facing the motor shaft defines an interior space within which the fan is located, wherein the front guide portion includes a through hole extending through the front guide portion to place the interior space in fluid communication with the chamber.

The electric tool of the application only slightly changes the wind scooper of the motor fan, so that the noise problem is solved. In particular, the rear portion of the air guide housing is elongated into engagement with the housing of the power tool, in particular the motor housing, this modification being such that, in the case where the front guide portion of the air guide housing has been extended into engagement with the motor housing, a closed chamber is defined between the air guide housing and the motor housing, and a through hole is formed in the front guide portion of the air guide housing that places the closed chamber in fluid (gas) communication with the interior space defined by the front guide portion that houses the fan. The above-described slight modification of the air guide housing forms a structure in which the closed chamber is combined with the through hole, achieving the technical result of bringing the closed chamber into gaseous communication with the interior space (of the air flow present) of the electric tool via the through hole, thereby creating a helmholtz silencer without adding any additional components and without changing any structure other than the air guide housing. The invention provides the technical effects of heat dissipation and noise reduction on the premise of not modifying the original structure of the electric tool and not adding new parts. By dividing the above-described closed chamber into a plurality of sub-chambers as appropriate and providing one or more through holes for each sub-chamber, an enhanced sound deadening effect can be achieved or sound deadening effects for noise of different frequencies can be achieved. In particular, the sound frequency sensitive to the human body can be silenced by reasonably designing the size of the cavity or the subchamber and the extending direction, the size, the number and the arrangement of the through holes, so that good use experience is provided for a user.

Drawings

The foregoing and other aspects, features, and advantages of the present application will be more fully understood from the following detailed description given in connection with the accompanying drawings. The drawings are for purposes of illustration and description only, and are not drawn to scale for illustrating the principles of the present application.

Fig. 1 is a perspective view of an angle grinder as an example of the electric tool of the present application.

Fig. 2 is a front view of the angle grinder of fig. 1, with portions cut away longitudinally.

FIG. 3 is another perspective view of the angle grinder of FIG. 1 with the main housing removed to show the internal components of the angle grinder.

Fig. 4 is a view corresponding to fig. 3, with parts being cut longitudinally.

Fig. 5 is a view corresponding to fig. 2, in which only the main housing and the hood of the angle grinder are shown.

Fig. 6 is a partial enlarged view of fig. 5.

Fig. 7 is a rear view of the air guide housing of the angle grinder.

Fig. 8 is a perspective view of a wind scooper of the angle grinder.

Fig. 9 is another perspective view of a wind scooper of the angle grinder.

Detailed Description

The principles of the present application are described below by way of example of an angle grinder with reference to the accompanying drawings. However, those skilled in the art will appreciate that the power tool of the present application is not limited to angle grinders.

FIGS. 1 and 2 illustrate an angle grinder of the present application in perspective view and in partial cross-sectional view; in fig. 3-5, portions of the components are removed to highlight the focus of the present application, and fig. 6 is a partial enlarged view illustrating the point of the invention of the present application; fig. 7-9 are various angled detail views of the air scoop of the angle grinder, more clearly showing the focus of the present application. The following detailed description is provided in connection with these figures.

As shown in fig. 1, the angle grinder generally includes a main body 10 and a head 20 connected to the main body 10. The main body 10 may include a main housing 12 formed by connecting a motor housing 11 and a component housing 13, a motor 14 accommodated in the motor housing 11 and including a motor shaft 15 (fig. 2), and an electric component accommodated in the component housing 13 and an associated support structure supporting the electric component. The head 20 may include a head housing 22, a transmission 24 (fig. 2) housed within the head housing 22 and including an output shaft 25, and a collet device 26 (fig. 2) mounted to the output shaft 25, wherein the collet device 26 partially protrudes from the head housing 22 and is configured for mounting a tool of a power tool, particularly a blade of an angle grinder. The main housing 12 and the head housing 22 of the angle grinder together form the housing of the angle grinder. Also shown is a shroud 29 attached to the head 20, the shroud 29 partially surrounding the abrasive sheet when mounted to the jaw apparatus 26 to prevent the abrasive sheet and resultant debris rotating at high speeds during operation of the angle grinder from splashing against the operator.

The motor housing 11 and the element housing 13 forming the main housing 12 may be integrally formed, or may be separate components that are separately formed and reattached together. The main housing 12 has a contoured configuration suitable for being held by an operator to operate the angle grinder. Optionally, the main housing 12 includes features for increasing friction between the hand and the housing when held by the hand of an operator. In the illustrated embodiment, the feature may comprise a sheet element 17 of plastic or rubber material attached to an outer surface of the main housing 12 (in particular at least a portion of the motor housing 11 and/or at least a portion of the element housing 13), alternatively or additionally, the feature may also comprise a protrusion and/or recess formed on the outer surface of the motor housing 11 and/or the element housing 13. One or both of the motor housing 11 and the element housing 13 forming the main housing 12 may be attached from opposite halves. The switch 101 is provided on the motor housing 11 at a position that is convenient for an operator to operate (e.g., press or slide) while holding the main body 10, for example, on the side that is convenient for the thumb of the right hand when held by the right hand of the operator as shown in the drawing.

The main housing 12, in particular the motor housing 11 thereof, defines a motor space in which the motor 14 is accommodated. The motor 14 mainly includes the motor shaft 15 described above, and a motor rotor and a motor stator arranged radially outward around the motor shaft 15. The main housing 12, in particular the element housing 13 thereof, defines an element space in communication with said motor space for arranging various electrical elements required for the operation of the angle grinder. These electrical components include a controller for controlling the motor 14, control or electrical components for controlling the operation of the angle grinder, various switches, etc., which may be mounted on one or more circuit boards. Also shown is a power cord 19 for connection to an external power source (e.g., an external ac or dc power source) to power the motor 14. The configuration and structure of the motor 14 and electrical components within the main housing 12 is not critical to the present application and is not described in detail herein. The application is not limited to power tools that use an external power source to power a motor, as power tools that include a battery pack for powering the motor are also possible.

As shown in fig. 2, in the present application, the direction in which the motor shaft 15 extends is defined as an axial direction L, and the motor shaft 15 has a central axis or rotation axis extending along the axial direction L and is rotatable therearound. For convenience of description, the directional terms "front" and "rear" along the axial direction L are also defined herein. In the axial direction L, the head 20 (and the head housing 22) are located in front of the main body 10 (and the main housing 12), and the element housing 13 of the main housing 12 is located behind the motor housing 11. Directional terms also used in this application include: a radial direction perpendicular to the axial direction L, a circumferential direction around the axial direction L, and a lateral direction a extending from the output shaft 25, wherein the lateral direction a is perpendicular to the axial direction L.

The head housing 22 of the head 20 is attached to the motor housing 11 of the main housing 12 of the main body 10 from the front, and the head housing 22 may include two opposite halves similar to the two halves of the main housing 12 or may include two halves opposite from top to bottom. The transmission 24 of the head housing 22 mainly includes a pair of bevel gears accommodated in the head housing 22 and an output shaft 25 protruding from the head housing 22. The drive gear 21 of the pair of bevel gears is attached to or integrally formed with the motor shaft 15 extending from the motor housing 11 into the head housing 22 to be driven by the motor shaft 15 to rotate in synchronization therewith about the central axis of the motor shaft 15 when the motor 14 is started. The driven gear 23 of the pair of bevel gears, which meshes with the driving gear 21, is attached to or integrally formed with the output shaft 25 of the transmission 24, so that the driven gear 23 is rotated by the driving gear 21, and in turn, drives the output shaft 25 to rotate together in synchronization about the output axis of the output shaft 25 extending in the lateral direction a. To this end, the transmission 24 converts rotation about the axial direction L from the motor shaft 15 into rotation about the lateral direction a of the output shaft 25 and outputs the rotation. These will not be described again.

The angle grinder includes an air inlet 32 (fig. 1 and 2) that allows air flow into the interior of the angle grinder and an air outlet 34 (fig. 1) that allows air flow out of the interior of the angle grinder, and defines a gas flow path through which air flow flows within the angle grinder after entering the angle grinder via the air inlet 32, before exiting the angle grinder via the air outlet 34. The angle grinder further comprises a fan 40, a deflector 50 and a fan housing 60 located in the gas flow path, wherein the fan 40, the deflector 50 and the fan housing 60 are located within the main housing 12 of the main body 10, in particular the motor housing 11. The air inlet 32 and the air outlet 34 are located on opposite sides of the fan 40, respectively, on the air flow path on which the air guide cover 60 and the air director 50 are located on the upstream side of the fan 40 near the air inlet 32 and the downstream side near the air outlet 34, respectively, such that the air guide cover 60 can prevent the air flow from flowing backward toward the air inlet 32 toward the upstream side and the air director 50 can direct the air flow toward the downstream side toward the air outlet 34. When the motor 14 is started, the fan 40 driven by the motor shaft 15 to rotate at a high speed sucks or draws air into the angle grinder through the air inlet 32, then the air flow sequentially flows through and cools the circuit board and the electric components located in the component housing 13 and the motor 14 located in the motor housing 11, then the air flows through the fan 40 and is discharged out of the angle grinder through the air outlet 34 under the guidance of the deflector 50 on the downstream side of the fan 40, thereby achieving a sufficient heat dissipation effect.

Specifically, in the illustrated embodiment, the air inlet 32 and the air outlet 34 are disposed behind and in front of the angle grinder (or its motor 14 and fan 40), respectively. As illustrated, the air intake 32 may include a first air intake 322 through the rear end wall of the component housing 13 and a second air intake 324 formed on the side wall of the component housing 13 proximate the rear end wall, alternatively, the air intake 32 may include one or both of the first air intake 322 and the second air intake 324, and the second air intake 324 may be formed on any one or any several of the side walls of the component housing 13. The first air inlet 322 and the second air inlet 324 may be in the form of slots arranged in parallel as shown, alternatively they may be configured as any arrangement of holes or slots or window structures.

The air outlet 34 is provided on the head housing 22 of the head 20 of the angle grinder, in particular on the front wall 27 facing forward, on the upper side ("upper" and "lower" are understood with reference to the orientation shown) opposite to the lower side on which the output shaft 25 is located. Although the air outlet 34 is illustrated as two generally rectangular shaped windows, those skilled in the art will appreciate that the air outlet 34 may be configured as any arrangement of holes or slots.

As shown in fig. 2 and 4, the fan 40 is disposed on the motor shaft 15 of the motor 14 such that the motor shaft 15 rotates the fan 40 together about its central axis when the motor 14 is started, to cause the air flow to accelerate. The fan 40 may be an axial flow fan as is well known in the art, or may be replaced with any other suitable fan configuration. In the illustrated embodiment, the fan 40 may include a body 42 secured to the motor shaft 15, rear blades 44 extending rearwardly from the body 42, and front blades 46 extending forwardly from the body 42. The rear vane 44 may be a plurality of helical or other shaped vanes evenly spaced about the central axis of the body 42 (coaxial with the central axis of the motor shaft 15). Alternatively, but not necessarily, the trailing blades 44 may include two sets of helical blades differing in at least one dimension (e.g., helix angle, length dimension extending away from the body 42 in the axial direction L, width dimension extending helically, etc.), such as the two sets of helical blades being arranged in an alternating manner and spaced apart. Similarly, the front vanes 46 extending forward from the body 42 toward the deflector 50 may also have any suitable structural configuration. The adjacent leading blades 46 and the adjacent trailing blades 44 each define a blade gap that communicates with each other in the axial direction L.

As shown in fig. 2, the deflector 50 may include an inner annular portion 52, an outer annular portion 54, and a body portion 56 connecting the inner annular portion 52 and the outer annular portion 54. The inner annular portion 52 is configured to engage the bearing 35 supporting the motor shaft 15 near the front end of the motor shaft 15, and the outer annular portion 54 is configured to be sandwiched between the head housing 22 and the motor housing 11 of the main housing 12 in the axial direction L and abut the interface 70 between the motor housing 11 and the front edge 71 of the air guide cover 60 in the circumferential direction around the axial direction L. The body portion 56 includes guide vanes 57 arranged at intervals in the circumferential direction, and guide gaps 59 (fig. 2) are formed between adjacent guide vanes 57. The guide vanes 57 and the guide gap of the body portion 56 of the deflector 50 are configured to cooperate with the gaps between the front blades 46 and the front blades 46 of the fan 40 to direct the airflow toward the air outlet 34.

On the rear side of the fan 40 opposite the deflector 50, a fan housing 60 is provided between the fan 40 and the motor 14. Both the deflector 50 and the hood 60 are fixed to the motor housing 11 so as to be stationary during operation of the angle grinder.

The air scoop 60 may include an annular body 62 defining a central through hole 65 that allows the motor shaft 15 to pass therethrough, having an inner edge 64 that is proximate to the motor shaft 15 and an outer edge 66 that is distal from the motor shaft 15. The inner diameter of the central through hole 65 may be designed to be approximately equal to (or slightly less than or slightly greater than) the distance of the last and radially innermost blade tip inner end point 45 of each rear blade 44 of the fan 40 in the axial direction L from the central axis of the motor shaft 15 (i.e., the minimum radial dimension of the blade tip end of each rear blade 44 from the central axis of the motor shaft 15). In other words, the rear blades 44 of the fan 40 may be partially exposed to the central through hole 65 of the cowl 60, as viewed from the rear to the front in the axial direction L. The air scoop 60 further includes a front guide portion 72 extending forward in the axial direction L from the outer edge 66 of the annular body 62 and radially outwardly to (the inner peripheral surface 18 of) the motor housing 11, and a rear portion 74 extending rearward in the axial direction L from the outer edge 66 of the annular body 62 and radially outwardly to the motor housing 11.

Referring to fig. 5-9, in the illustrated embodiment, the front guide 72 may have a forward horn shape and may be formed to extend in a curved fashion from the outer edge 66 of the annular body 62 to the front edge 71 engaged with the inner peripheral surface 18 of the motor housing 11, the inner peripheral surface 18 of the motor housing 11 and the front edge 71 of the front guide 72 of the cowl 60 forming the above-described interface 70 in the radial direction. Specifically, as illustrated, the front guide 72 may extend from the outer edge 66 of the annular body 62 to the front edge 71 of the front guide 72 in a curved shape that is convex toward the motor housing 11 away from the motor shaft 15, the front guide 72 having a concave inner surface 82 toward the motor shaft 15, an opposite convex outer surface 84, and a forward facing front end surface 86. As before, the outer annular portion 54 of the deflector 50 engages the front face 31 of the motor housing 11 (forming the interface 70 between the motor housing 11 and the air guide housing 60) and the front face 86 of the air guide housing 60. An interior space 95 is defined by the front guide portion 72 (specifically, the inner surface 82 thereof) and is located between the front guide portion 72 of the air guide cover 60 and the deflector 50 in the axial direction L, and the fan 40 and the inner annular portion 52 and the body portion 56 of the deflector 50 are accommodated within the interior space 95. The front guide 72 or its inner surface 82 is shaped and dimensioned to guide the air flow caused by the rotation of the fan 40 forward along the inner surface 82, which air flow is then guided to the air outlet 34 via the guide gaps between the guide vanes 57 of the deflector 50. In addition, the front guide 72 and the annular body 62 also function to block contaminants such as impurities from the head from entering the rear motor 14.

As illustrated, the rear portion 74 of the air scoop 60 may be flared rearward and may be formed to extend in a curved fashion from the outer edge 66 of the annular body 62 to a rear edge 73 that engages the motor housing 11 (specifically the inner peripheral surface 18 thereof). As illustrated, the rear portion 74 may extend from the outer edge 66 of the annular body 62 to the rear edge 73 of the rear portion 74 in a curved shape that projects outwardly away from the motor shaft 15 toward the motor housing 11. Accordingly, motor housing 11 includes features for engaging rear edge 73 of rear portion 74 to prevent rearward displacement of air chute 60 relative to motor housing 11 in axial direction L or to axially position air chute 60 when air chute 60 is installed. Specifically, in the illustrated embodiment, referring to fig. 6, this feature is a groove 77 formed in a stepped portion 76 on the inner peripheral surface 18 of the motor housing 11, the groove 77 being for at least partially receiving a boss 79 protruding outwardly (rearwardly) from the rear edge 73 of the air guide cover 60, thereby forming an interface 80 between the rear portion 74 of the air guide cover 60 and (the inner peripheral surface 18 of) the motor housing 11. Alternatively, the step 76 may not include the groove 77 nor the rear edge 73 of the cowl 60 and the same is achieved by the forward facing surface of the step 76 being in abutting engagement with the rearward facing surface of the rear edge 73 of the cowl 60. Alternatively, the step 76 of the motor housing 11 and the rear edge 73 of the air guide cover 60 may be configured to include a convex portion and a concave portion, respectively, contrary to the illustrated structure, and the same object can be achieved.

As previously described, the front guide portion 72 of the air guide cover 60 engages (the inner peripheral surface 18 of) the motor housing 11 and the interface 70 therebetween is engaged, and preferably forms a seal, by the rearwardly facing surface of the outer annular portion 54 of the air guide 50, the rear portion 74 of the air guide cover 60 engages (the inner peripheral surface 18 of) the motor housing 11 and the interface 80 therebetween is engaged, and preferably forms a seal, by the stepped portion 76 on the inner peripheral surface 18 of the motor housing 11, thereby forming a substantially closed chamber 85 between (the front guide portion 72 and the rear portion 74 of) the air guide cover 60 and (the inner peripheral surface 18 of) the motor housing 11.

In addition, the front guide 72 of the hood 60 includes a through-extending through-hole 75 extending from its inner surface 82 to its outer surface 84, whereby the through-hole 75 is in fluid communication with the chamber 85. As shown in fig. 5 and 6, the side of the through hole 75 faces the inner space 95, in which the fan 40 rotating at a high speed, the air flow forced to flow at a high speed, and noise of various frequencies formed by the foregoing and other reasons exist; the other side of the through hole 75 faces the closed chamber 85. Air flow caused by the high speed rotation of the fan 40 flows into and out of the chamber 85 through the through holes 75, and the air flowing into and out generates a pressure difference in the chamber 85, resulting in air vibration. When the sound wave frequency of the air flow (entering the chamber 85) existing in the inner space 95 matches with the air vibration frequency inside the chamber 85, a resonance phenomenon occurs, the energy of the incident sound wave is consumed, and the absorption of the sound wave with the specific frequency is realized.

As described above, the angle grinder of the present application does not add any new components, does not greatly modify the original structure, and only slightly improves the structure of the air guide cover 60, so that the rear portion 74 thereof extends to be engaged with the motor housing 11, that is, the helmholtz type noise reducing device capable of achieving the noise reducing effect is formed. The silencing and noise-reducing effect is achieved under the condition that the structural complexity of the angle grinder is not increased, and therefore the cost is not increased by the aid of the minimum structural change. Except for the air guide cover 60, the structure of any other parts of the angle grinder is not required to be modified, additional structural space is not required to be required, the external size of the angle grinder is not required to be changed, and the cost is not required to be increased.

In order to obtain different natural frequencies of the helmholtz type muffler device, parameters of the chamber 85 or the through holes 75 may be suitably changed, including, but not limited to, the size (e.g., dimensions or volumes) of the chamber and/or the direction of extension, number, size, arrangement, etc. of the through holes 75.

In the illustrated embodiment, as shown in fig. 3,4,7-9, the air scoop 60 includes a plurality of dividing walls or ribs 55 extending axially L rearward and radially outward from the outer surface 84 of the front guide portion 72 to (the inner peripheral surface 18 of) the motor housing 11 and to the rear portion 74. Each rib 55 extends from the hood 60 into engagement with the motor housing 11 and the rear portion 74, dividing the chamber 85 into a plurality of subchambers 85a (fig. 3), each subchamber 85a communicating with one or more of the through holes 75. In this way, a plurality of helmholtz type muffling apparatuses are formed. The size of each subchamber 85a may be the same or different from the arrangement of the through holes 75 corresponding to that subchamber 85a to provide a helmholtz type muffler device with the same or different natural frequencies to eliminate noise at different frequencies.

The arrangement of the ribs 55 may be varied to provide subchambers 85a of various sizes or volumes. In the illustrated embodiment, each rib 55 may extend in a plane parallel to the axial direction L. As one example, as shown in fig. 7, some of the ribs 55a extend in the transverse direction a in the same direction as the output shaft 25, some of the ribs 55b extend in the transverse direction a in the opposite direction to the output shaft 25, and other ones of the ribs 55c and 82d extend in the other direction perpendicular to the axial direction L and the transverse direction a in the opposite direction to each other. In some embodiments not shown in the figures, these planes parallel to the axial direction L may alternatively be arranged radially around the central axis of the motor shaft 15. In addition, it is contemplated that each rib may extend straight in a circumferential direction around the axial direction L, in a ring shape. The ribs 55 may also have any curved configuration that is non-planar. For example, the ribs may extend helically or in other curved shapes around the axial direction L. In other embodiments, ribs adjacent to each other may be interconnected to form a grid-like subchamber arrangement of various shapes or sizes.

Different configurations of through holes 75 may be provided to obtain different resonance frequencies in combination with different subchambers 85a. Different resonance frequencies can be obtained by combining the same size subchambers 85 with different configurations of through holes. The configuration of the through holes associated with a subchamber 85a may include one or more of the following: the number of through holes (extending through the front guide portion 72 in parallel or perpendicular or inclined to the axial direction L) associated with the sub-chamber 85, the size of each through hole, the arrangement of each through hole (the relative positional relationship or distance between each through hole, etc.), the empty depth of each through hole, etc. The hole depth of the through hole depends on the wall thickness of the portion of the front guide 72 defining the through hole 75. In order to obtain different via depths, the wall thickness of the portion may be locally increased or thinned.

As is also apparent from the perspective view of the air scoop 60 shown in fig. 7-9, the air scoop 60 includes a notch 88 formed in the front guide 72. Accordingly, the motor housing 11 includes an additional air outlet (not shown) at a position corresponding to the notch 88. The additional air outlet is combined with the air outlet 34 to facilitate smooth and sufficient discharge of air flow in the angle grinder. Of course, the additional air outlets may have any suitable shape, size, and arrangement. In the illustrated embodiment, the additional air outlet that mates with the notch 88 of the air scoop 60 is provided on the side of the output shaft 25 that extends (upper side in fig. 7 and lower side in the other figures), while the air outlet 34 is located on the opposite side of the head housing 22 (upper side in fig. 1-4). This is advantageous in maximizing the efficiency of the air discharge. It should be understood by those skilled in the art that the wind scooper 60 of the present application may not include the notch 88 or the motor housing 11 may not be provided with an additional air outlet, or the positions of the notch 88 of the wind scooper 60 and the corresponding additional air outlet on the motor housing 11 may be changed along the circumferential direction.

In the perspective views of fig. 8-9, the hood 60 may include a region 90 on the front guide 72 that does not include ribs, although not shown, that portion of the space is used to house structural components of the motor 14. To this end, in this region, the wind scooper 60 may include features that protrude from or attach to the outer surface for mounting or securing the respective structural components of the motor 14.

The basic principles of the present application are described above with respect to the illustrated corner grinder example. According to the method, under the condition that the structure of the angle grinder does not need to be greatly modified, new parts are not added, and therefore the cost is not increased, only the wind scooper part is slightly modified, namely the technical effect of creating the silencer to eliminate noise is achieved, and meanwhile the radiating function is not affected.

It will be appreciated by those skilled in the art after reading the above description that the principles of the present application are not only applicable to angle grinders in which the blade is a grinding plate, but are applicable to any power tool that includes a motor, fan and fan housing structure, such as a cutter in which the blade is a cutting plate; the principle of the application is not only applicable to electric tools with motor shafts and output shafts arranged vertically, but also applicable to electric tools with motor shafts and output shafts arranged approximately in parallel or obliquely; the principles of the present application are applicable not only to power tools in which the transmission is a one-stage transmission comprising only a pair of bevel gears, but also to power tools in which the transmission comprises multiple stages of bevel gear meshing pairs and/or spur gear meshing pairs.

It will be appreciated by persons skilled in the art that the foregoing detailed description of the basic principles, main features and advantages of the invention is not intended to limit the invention in any way, but rather to cover such modifications as may be obtained by means of equivalent substitutions or equivalent arrangements, which fall within the purview of the present invention.

Claims (15)

1. A power tool, comprising:

a main housing (12) housing a motor (14) and defining at least one of an air inlet (32) and an air outlet (34), the motor (14) having a motor shaft (15) extending in an axial direction (L);

a fan (40) mounted on the motor shaft (15) to rotate therewith; and

a wind scooper (60) arranged between the fan (40) and the motor (14) along the axial direction (L),

wherein, wind scooper (60) includes: an annular body (62) defining a central through hole (65) through which air flow from the air inlet into the power tool is permitted to flow; -a front guide (72) extending axially (L) from the annular body (62) forward away from the motor (14) and radially outwards perpendicular to the axial direction (L) to engage with the main housing (12); and a rear portion (74) extending radially outwardly from the annular body (62) into engagement with the main housing (12) such that a closed chamber (85) is defined between the front guide portion (72), rear portion (74) and main housing (12) of the wind scooper (60),

wherein an inner surface (82) of the front guide (72) facing the motor shaft (15) defines an inner space (95), the fan being located within the inner space (95),

wherein the front guide (72) comprises a through hole (75) penetrating the front guide (72) to place the inner space (95) in fluid communication with the chamber (85).

2. The power tool of claim 1, wherein the rear portion (74) extends axially (L) rearward toward the motor (14) while extending radially outward.

3. The power tool of claim 2, wherein the rear portion (74) extends from the annular body (62) to a rear edge (73) engaged with the main housing (12) in a curved form that is convex or concave away from the motor shaft (15) or in a straight tapered configuration.

4. A power tool according to claim 3, wherein the main housing (12) comprises a step (76) configured for abutting against a rear edge (73) of the air guide cover (60) to prevent rearward displacement thereof in the axial direction (L).

5. The power tool of any one of claims 1-4, wherein the front guide (72) extends from the annular body (62) to a front edge (71) engaging an inner peripheral surface (18) of the main housing (12) in a curved form that is convex or concave away from the motor shaft (15) or in a straight tapered configuration.

6. The power tool according to claim 5, wherein a front edge (71) of the front guide portion (72) engages with an inner peripheral surface (18) of the main housing (12) to form an interface (70), the head housing (22) of the power tool attached to the main housing (12) or another surface fixed relative to the main housing (12) abutting the interface (70) in an axial direction (L).

7. The power tool of claim 6, further comprising a deflector (50), in the axial direction (L), the air guide shroud (60) and the deflector (50) being located on an upstream side of the fan (40) near the air intake (32) and a downstream side near the air outlet (34), respectively, the deflector (50) comprising an outer annular portion (54) sandwiched between the head housing (22) and the main housing (12) along the axis (L), the outer annular portion (54) providing the other surface.

8. The power tool of claim 7, wherein the deflector (50) further comprises an inner annular portion (52) and a body portion (56) connecting the outer annular portion (54) and the inner annular portion (52), the body portion (56) comprising deflector blades (57), adjacent deflector blades (57) defining a deflector gap (59) for guiding the airflow to the air outlet.

9. The power tool according to any one of claims 1-8, wherein the through hole (75) comprises a plurality of through holes arranged in a circumferential direction around the axial direction (L), the through hole (75) extending through the front guide (72) perpendicular, parallel or oblique to the axial direction (L).

10. The power tool of claim 9, wherein the front guide (72) includes a plurality of ribs (55) extending from an outer surface (84) opposite the inner surface (82) to divide the chamber (85) into a plurality of subchambers (85 a), each subchamber (85 a) being in fluid communication with at least one of the plurality of through holes (75).

11. The power tool of claim 10, wherein at least one of:

the plurality of ribs (55) includes one or more ribs extending from an outer surface (84) to the rear portion (74) and/or to an inner peripheral surface (18) of the main housing (12);

the plurality of ribs (55) includes one or more ribs extending from the outer surface (84) to intersect with other ribs to form a subchamber (85 a);

the plurality of ribs (55) comprises one or more ribs extending straight in a plane containing the axial direction (L) or in a plane perpendicular to the axial direction (L) or in a plane oblique to the axial direction (L); and

the plurality of ribs (55) includes one or more ribs extending helically around the axial direction (L).

12. The power tool of any one of claims 1-11, wherein the air guide housing (60) includes a notch (88) formed on the front guide (72), the main housing (12) including an auxiliary air outlet in fluid communication with the notch to direct an air flow inside the power tool out of the power tool.

13. The power tool of any one of claims 1-12, further comprising:

the transmission (24) comprises an output shaft extending parallel or coaxial to the axial direction (L), or extending perpendicular to the axial direction (L), or extending obliquely to the axial direction (L).

14. The power tool of claim 13, further comprising a head housing (22) housing the transmission (24) and attached to a front end of the main housing (12), the air intake (32) and air outlet (34) being provided on a rear end of the main housing (12) and the head housing (22), respectively.

15. The power tool of any one of claims 1-14, wherein the power tool is an angle grinder.