An impact screwdriver

Abstract

The application discloses an impact screwdriver and belongs to the technical field of electric devices. The impact screwdriver comprises a casing and a motor. The casing has a containing space. The casing comprises a first half casing and a second half casing which are detachably connected. A first protrusion and a second protrusion are respectively protruded on the part of the inner wall surface of the containing space in the first direction from the first rear end plate of the first half casing and the second rear end plate of the second half casing. The first protrusion and the second protrusion are spliced to form a positioning protrusion. The motor is arranged in the containing space. The motor shaft of the motor is arranged in the first direction. A fan is sleeved on the rear end of the motor shaft close to the rear end plate. A positioning groove is arranged on the wall surface of the fan close to the rear end plate. The positioning protrusion is coplanar with the fan or is partially contained in the positioning groove. The impact screwdriver can avoid the positioning protrusion of the casing by using the positioning groove of the fan. The length of the whole impact screwdriver can be effectively shortened while achieving the purpose of positioning the motor. The miniaturization of the impact screwdriver is facilitated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric power equipment, in particular to an impact screwdriver. BACKGROUND

[0002] The impact screwdriver is a household tool with impact function, which can screw and punch, and has the advantages of fast and convenient, cheap and practical, and wide application, so it is widely used in family life.

[0003] The miniaturization of the impact screwdriver is the future development trend, and the important way to realize the miniaturization is to reduce the volume by improving the compactness of the structure. The existing impact screwdriver has the problem of large overall size, which is not easy to hold for the user and has poor experience, so how to provide a compact structure, short overall length and small impact screwdriver is a technical problem to be solved at present. SUMMARY

[0004] The purpose of the present application is to provide an impact screwdriver with compact structure and short overall length.

[0005] To achieve this purpose, the technical scheme adopted by the present application is as follows:

[0006] An impact screwdriver, comprising:

[0007] A housing having a containing space, the housing comprising a first half-shell and a second half-shell connected detachably, the first half-shell comprising a first rear end plate, a first protrusion being provided on a part of the inner wall surface of the first rear end plate facing the containing space along a first direction a, the second half-shell comprising a second rear end plate, a second protrusion being provided on a part of the inner wall surface of the second rear end plate facing the containing space along the first direction a, the first rear end plate and the second rear end plate being spliced to form a rear end plate of the housing, and the first protrusion and the second protrusion being spliced to form a positioning protrusion;

[0008] A motor disposed in the containing space, the motor comprising a motor shaft and a fan, the motor shaft being disposed extending along the first direction a, the fan being sleeved on the rear end of the motor shaft close to the rear end plate, a positioning groove being provided on the wall surface of the fan close to the rear end plate, and the positioning protrusion being coplanar with the fan or being partially contained in the positioning groove.

[0009] As a preferred, the motor further comprises a motor bearing, the motor bearing being sleeved on the motor shaft and located on the side of the fan close to the rear end plate.

[0010] A bearing chamber is provided on the positioning protrusion along the first direction a, and the motor bearing is disposed in the bearing chamber.

[0011] As preferred, a first half-cavity with a side opening towards the second protrusion is arranged on the first protrusion, a second half-cavity with a side opening towards the first protrusion is arranged on the second protrusion, and the first half-cavity and the second half-cavity are spliced to form the bearing chamber.

[0012] As preferred, at least one of the first half-cavity and the second half-cavity comprises a first accommodating portion and a second accommodating portion which are connected in a stepped manner, the first accommodating portion is used for accommodating an end portion of the motor shaft;

[0013] The second accommodating portion is used for accommodating the motor bearing, the second accommodating portion comprises a first stop surface and a first arc-shaped inner wall surface, the first stop surface is arranged perpendicular to the first direction a and is used for stopping a rear end surface of the motor bearing, and the first arc-shaped inner wall surface is arranged around the first direction a and is used for stopping an outer wall surface of the motor bearing, and the first arc-shaped inner wall surface is connected with an end surface of the positioning protrusion.

[0014] As preferred, at least one of the first half-cavity and the second half-cavity comprises a third accommodating portion, a fourth accommodating portion and a fifth accommodating portion which are connected in sequence, the third accommodating portion is used for accommodating an end portion of the motor shaft;

[0015] The fourth accommodating portion is used for accommodating the motor bearing, the fourth accommodating portion comprises a second stop surface, a second arc-shaped inner wall surface and a third stop surface which are connected in a U-shaped manner, the second stop surface and the third stop surface are both arranged perpendicular to the first direction a, and the second stop surface and the third stop surface stop a rear end surface and a front end surface of the motor bearing respectively, and the second arc-shaped inner wall surface is arranged around the first direction a and is used for stopping an outer wall surface of the motor bearing;

[0016] The fifth accommodating portion comprises a third arc-shaped inner wall surface which is connected with the third stop surface, and the third arc-shaped inner wall surface is connected with an end surface of the positioning protrusion.

[0017] As preferred, a first hollow groove which is in communication with the first half-cavity is arranged on the first protrusion in a radial direction;

[0018] And / or a second hollow groove which is in communication with the second half-cavity is arranged on the second protrusion in a radial direction.

[0019] As preferred, the number of the first hollow grooves is plural, and the plural first hollow grooves are arranged on the first protrusion in a radial manner;

[0020] The number of the second hollow grooves is plural, and the plural second hollow grooves are arranged on the second protrusion in a radial manner.

[0021] As a preference, the first half shell is a left half shell, and the second half shell is a right half shell.

[0022] As a preference, the casing is provided with air inlets, and the air inlets and the projections at least partially overlap in a plane parallel to the first direction a.

[0023] As a preference, the air inlets are provided in a plurality of numbers and are spaced apart in a circumferential direction around the first direction a on the casing.

[0024] Advantages of the present application:

[0025] The impact screwdriver provided by the present application has the positioning protrusion arranged on the inner wall surface of the part of the rear end plate of the casing towards the accommodating space, and the positioning protrusion can be accommodated in the positioning groove on the fan, so that the motor can be positioned while avoiding the positioning protrusion by the positioning groove, thereby effectively shortening the overall length of the impact screwdriver and facilitating the miniaturization of the impact screwdriver. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a structural schematic view of the impact screwdriver provided by the present application;

[0027] Figure 2 is a first schematic view of the first half shell and the second half shell after being assembled according to the present application;

[0028] Figure 3 is a second schematic view of the first half shell and the second half shell after being assembled according to the present application;

[0029] Figure 4 is a sectional view of the casing and the motor according to the present application;

[0030] Figure 5 is a structural schematic view of the motor according to the present application;

[0031] Figure 6 is a partial sectional view of the impact screwdriver according to the present application;

[0032] Figure 7 is a first structural schematic view of the second half shell according to the present application;

[0033] Figure 8 is a second structural schematic view of the second half shell according to the present application;

[0034] Figure 9 is a first structural schematic view of the first half shell according to the present application;

[0035] Figure 10 is a second structural schematic view of the first half shell according to the present application;

[0036] Figure 11 Fig. 4 is a structure schematic view of the projection of the tuyere and the first protrusion in the first direction overlapping each other according to the present application.

[0037] Fig. 1 is a structure schematic view of the first half shell and the second half shell according to the present application.

[0038] 100, housing; 200, motor; 300, holding part; 400, power part;

[0039] 110, first half shell; 111, first protrusion; 112, first half cavity; 1121, third accommodating portion; 1122, fourth accommodating portion; 1123, fifth accommodating portion; 113, first hollow groove;

[0040] 120, second half shell; 121, second protrusion; 122, second half cavity; 1221, first accommodating portion; 1222, second accommodating portion; 123, second hollow groove;

[0041] 130, tuyere;

[0042] 210, motor shaft; 220, fan; 221, positioning groove; 230, motor bearing. DETAILED DESCRIPTION

[0043] The technical solutions of the present application will be described clearly and completely below in conjunction with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0044] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", are only for the purpose of description, and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions.

[0045] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0046] This embodiment provides an impact screwdriver that can perform knob screw operations and drilling operations, and is a commonly used power tool in people's daily lives.

[0047] like Figure 1 As shown, the impact screwdriver includes a working part, a gripping part 300, and a power part 400. The working part is the main actuating component of the impact screwdriver, on which a working head can be detachably connected. The working head moves to complete various tasks. The gripping part 300 is connected below the working part, and the two are in a roughly perpendicular state. The gripping part 300 is for the user to hold. The power part 400 is connected below the working part and is used to provide power for the movement of the working head. In this embodiment, the power part 400 is a battery pack detachably connected below the gripping part 300. Optionally, the battery pack is a lithium-ion battery pack. Lithium-ion battery packs have high energy density, which helps to increase the battery life of the impact screwdriver.

[0048] The impact screwdriver includes a housing 100 and a motor 200. The housing 100 has a receiving space, and the motor 200 is housed within this receiving space. The housing 100 is the external part of the working component. To facilitate the assembly of the relevant components for performing the operation into the receiving space inside the housing 100, such as... Figure 2 and Figure 3 As shown, the housing 100 is selected to be configured as a detachably connected first half-shell 110 and second half-shell 120.

[0049] Optionally, the first half-shell 110 and the second half-shell 120 can be an upper half-shell and a lower half-shell split vertically on a horizontal plane, or a left half-shell and a right half-shell split horizontally on a vertical plane, or an oblique upper half-shell and an oblique lower half-shell split along an inclined plane inclined to the vertical direction. In this embodiment, a left half-shell and a right half-shell are chosen to facilitate assembly to form the housing 100.

[0050] Specifically, the first half-shell 110 includes a first rear end plate and a first arc-shaped wall, with the portion of the inner wall of the first rear end plate facing the accommodating space along a first direction (the first direction being...). Figure 4The first half shell 110 includes a first rear end plate and a first arc-shaped wall. The first rear end plate is provided with a first protrusion 111 protruding in the first direction a on the inner wall surface of the part of the part of the inner wall surface of the accommodating space. The second half shell 120 includes a second rear end plate and a second arc-shaped wall. The second rear end plate is provided with a second protrusion 121 protruding in the first direction a on the inner wall surface of the part of the part of the inner wall surface of the accommodating space. The first rear end plate and the second rear end plate are spliced to form a rear end plate of the casing 100. The first arc-shaped wall and the second arc-shaped wall are spliced to form an inner side wall of the casing 100. The first protrusion 111 and the second protrusion 121 are spliced to form a positioning protrusion. Optionally, the first rear end plate and the second rear end plate are both semicircular, and the rear end plate of the casing 100 after splicing is circular. Further optionally, the first protrusion 111 and the second protrusion 121 are both half frustums, and the frustums have horizontal splicing surfaces. After the two splicing surfaces overlap, a positioning protrusion in the shape of a frustum can be spliced.

[0051] The motor 200 placed in the accommodating space includes a motor shaft 210 and a fan 220. The motor shaft 210 is arranged to extend in the first direction a. The motor shaft 210 has two end portions, wherein the end portion close to the rear end plate of the casing 100 is defined as a rear end portion, and the end portion away from the rear end plate of the casing 100 is defined as a front end portion. The fan 220 is sleeved on the rear end portion of the motor shaft 210 close to the rear end plate, and as shown in Figure 5 , a positioning recess 221 is arranged on the wall surface of the fan 220 close to the rear end plate. When the motor 200 is placed inside the casing 100, the positioning protrusion is coplanar with the fan 220 or is partially accommodated in the positioning recess 221. Such arrangement can position the motor 200 while avoiding the positioning protrusion in the positioning recess 221, thereby effectively shortening the overall length of the impact screwdriver and facilitating the miniaturization of the impact screwdriver. Through tests, it is known that such arrangement can reduce the overall size of the impact screwdriver by at least 1.5 mm.

[0052] Continuing to refer to Figures 4 to 6 , the motor 200 further includes a motor bearing 230 for supporting the motor shaft 210 to stably rotate. The motor bearing 230 is sleeved on the motor shaft 210 and located on the side of the fan 220 close to the rear end plate. In order to stably support the motor bearing 230, a bearing chamber is arranged on the positioning protrusion in the first direction a, and the motor bearing 230 is placed in the bearing chamber. Such arrangement does not need to additionally arrange a structure for supporting the motor bearing 230, which is conducive to simplifying the structure of the impact screwdriver, further shortening the overall length of the impact screwdriver, and realizing the miniaturization of the impact screwdriver.

[0053] Specifically, since the positioning protrusion is formed by splicing the first protrusion 111 and the second protrusion 121, in order to form the bearing chamber and reduce the difficulty of assembling the motor bearing 230 into the bearing chamber, as shown in Figure 9 and Figure 10As shown, a first semi-cavity 112 with a side opening facing the second protrusion 121 is provided on the first protrusion 111, that is, the side opening of the first semi-cavity 112 is located on the splicing surface of the first protrusion 111, and the first semi-cavity 112 extends radially into the first protrusion 111. Similarly, as Figure 7 and Figure 8 As shown, a second semi-cavity 122 with a side opening facing the first protrusion 111 is provided on the second protrusion 121. That is, the side opening of the second semi-cavity 122 is located on the splicing surface of the second protrusion 121, and the second semi-cavity 122 extends radially into the second protrusion 121. After the side openings of the first semi-cavity 112 and the second semi-cavity 122 overlap, the first semi-cavity 112 and the second semi-cavity 122 can form a bearing chamber.

[0054] Optionally, the first half-cavity 112 and the second half-cavity 122 can be simultaneously as follows: Figure 7 and Figure 9 The semi-enclosed structure shown can also be as follows: Figure 8 The open structure shown can also be either the first half-cavity 112 or the second half-cavity 122. Figure 7 , Figure 9 The semi-enclosed structure shown is another one as shown in the image. Figure 8 The open structure shown.

[0055] Continue to refer to Figure 8 As shown, when the second half-cavity 122 (or the first half-cavity 112) is an open structure, it includes a first accommodating portion 1221 and a second accommodating portion 1222 connected in a stepped manner. The first accommodating portion 1221 is used to accommodate the end of the motor shaft 210. Specifically, the first accommodating portion 1221 includes a first half-bottom surface and a first semi-arc surface that is circumferentially perpendicular to the first half-bottom surface and extends toward the second accommodating portion 1222. The first half-bottom surface is perpendicular to the first direction a and is used to limit the rear end of the motor shaft 210. The first semi-arc surface is used to enclose a portion of the space that accommodates the end of the motor shaft 210.

[0056] The second receiving portion 1222 is larger than the first receiving portion 1221 and is used to receive the motor bearing 230. Specifically, the second receiving portion 1222 includes a first abutment surface and a first arc-shaped inner wall surface. The first abutment surface is disposed perpendicular to the first direction a and is used to abut the rear end face of the motor bearing 230. The first arc-shaped inner wall surface is disposed around the first direction a and is used to abut the outer wall surface of the motor bearing 230. The end of the first arc-shaped inner wall surface away from the first abutment surface is connected to the end face of the positioning protrusion.

[0057] That is, the semi-cavity in the semi-open structure forms an opening at the top end surface of the positioning protrusion, and when both semi-cavities are in the semi-open structure, the openings of the two semi-cavities can be spliced to form an entrance that allows the motor bearing 230 to enter the bearing chamber. The semi-cavity thus arranged not only has a simple structure, but also provides another way for the motor bearing 230 to enter the bearing chamber, which helps to reduce the assembly difficulty. Of course, in addition to using the entrance to enter the bearing chamber, the motor bearing 230 can also be directly placed between the first semi-cavity 112 and the second semi-cavity 122 when the first half shell 110 and the second half shell 120 are spliced to form the machine shell 100, so as to be directly located in the bearing chamber.

[0058] Continuing to refer to Figure 9 When the first semi-cavity 112 (or the second semi-cavity 122) is in the semi-enclosed structure, it includes a third accommodating portion 1121, a fourth accommodating portion 1122, and a fifth accommodating portion 1123 connected in sequence. The third accommodating portion 1121 is used to accommodate the end of the motor shaft 210. Specifically, the third accommodating portion 1121 includes a second half bottom surface and a second half arc surface vertically surrounding the second half bottom surface and extending to the fourth accommodating portion 1122, the second half bottom surface is perpendicular to the first direction a and is used to limit the rear end of the motor shaft 210, and the second half arc surface is used to surround the space for accommodating the end of the motor shaft 210.

[0059] The fourth accommodating portion 1122 is used to accommodate the motor bearing 230, and the fourth accommodating portion 1122 includes a second stop surface, a second arc-shaped inner wall surface, and a third stop surface connected in a U shape. The second stop surface and the third stop surface are both perpendicular to the first direction a, and the second stop surface and the third stop surface stop the rear end surface and the front end surface of the motor bearing 230, respectively. The second arc-shaped inner wall surface is arranged around the first direction a and is used to stop the outer wall surface of the motor bearing 230. The fifth accommodating portion 1123 includes a third arc-shaped inner wall surface connected with the third stop surface, and the third arc-shaped inner wall surface is connected with the end surface of the positioning protrusion.

[0060] Compared with the open structure, the semi-cavity in the semi-enclosed structure can simultaneously limit the front end surface and the rear end surface of the motor bearing 230, and thus can stably support the motor bearing 230, and the support stability is strong. When both semi-cavities are in the semi-enclosed structure, the motor bearing 230 can only be placed between the first semi-cavity 112 and the second semi-cavity 122, so that the motor bearing 230 is directly located in the bearing chamber when the first half shell 110 and the second half shell 120 are spliced to form the machine shell 100.

[0061] It should be noted that when the half-cavity structures on the two protrusions are different, the first accommodating portion 1221 corresponds to the third accommodating portion 1121, that is, the second half bottom surface and the first half bottom surface can be spliced to form a complete bottom surface of the bearing chamber, and the second half arc surface and the first half arc surface can be spliced to form a space for accommodating the end portion of the motor shaft 210. The second accommodating portion 1222 corresponds to the fourth accommodating portion 1122 and the fifth accommodating portion 1123, and the second stop surface and the first stop surface can be spliced to form a complete annular surface, thereby stopping part of the rear end surface of the motor bearing 230, and the second arc-shaped inner wall surface and part of the first arc-shaped inner wall surface are spliced to form a space for accommodating the motor bearing 230, and the third stop surface in the form of a semicircle annularly stops the front end surface of the motor bearing 230. The third arc-shaped inner wall surface and the remaining part of the first arc-shaped inner wall surface are spliced to form a space for avoiding part of the motor shaft 210 located on the other side of the motor bearing 230.

[0062] As shown in Figure 10 , a first hollow groove 113 in communication with the first half-cavity 112 is formed on the first protrusion 111 in the radial direction. Such arrangement not only reduces the weight of the casing 100, but also facilitates heat dissipation of the motor bearing 230 during operation. Optionally, the number of first hollow grooves 113 is multiple, and the multiple first hollow grooves 113 are arranged radially on the first protrusion 111.

[0063] Further, continuing to refer to Figure 3 , a second hollow groove 123 in communication with the second half-cavity 122 is arranged on the second protrusion 121 in the radial direction. Optionally, the number of second hollow grooves 123 is multiple, and the multiple second hollow grooves 123 are arranged radially on the second protrusion 121.

[0064] It should be noted that whether the half-cavity structure on the first protrusion 111 and the second protrusion 121 is a half-enclosed structure or an open structure does not affect the arrangement of the hollow grooves.

[0065] In order to ensure the structural strength of the first protrusion 111 and the second protrusion 121, a reinforcing rib can be arranged circumferentially on the first protrusion 111 and the second protrusion 121, and the number of reinforcing ribs is preferably multiple, and the multiple reinforcing ribs are arranged radially, so that the structural strength of the protrusion is uniformly strengthened.

[0066] As shown in Figure 11 , an air inlet 130 is arranged on the casing 100, and the arrangement of the air inlet 130 facilitates heat dissipation during operation of the motor 200. In this embodiment, the projection of the air inlet 130 and the positioning protrusion on the plane parallel to the first direction a at least partially overlaps, thereby facilitating further reduction of the overall size of the impact screwdriver.

[0067] Optionally, the number of air inlets 130 is multiple, and the multiple air inlets 130 are arranged on the casing 100 along a circumferential direction around the first direction a. The shape of the air inlets 130 can be a waist shape, a rectangular shape, or an elliptical shape, etc.

[0068] Obviously, the above embodiments of the present application are merely exemplary for clarity and are not intended to limit the embodiments of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, it is not necessary and impossible to enumerate all the embodiments. Any modification, equivalent replacement, and improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. An impact screwdriver characterized by, Comprise: A casing having a containing space, the casing comprising a first half-shell and a second half-shell connected detachably, the first half-shell comprising a first back end plate, a first protrusion being convexly arranged on a part of inner wall surface of the containing space of the first back end plate along a first direction a, the second half-shell comprising a second back end plate, a second protrusion being convexly arranged on a part of inner wall surface of the containing space of the second back end plate along the first direction a, the first back end plate and the second back end plate being spliced to form a back end plate of the casing, the first protrusion and the second protrusion being spliced to form a positioning protrusion; A motor disposed in the containing space, the motor comprising a motor shaft and a fan, the motor shaft being disposed along the first direction a, the fan being sleeved on a rear end portion of the motor shaft close to the back end plate, a positioning groove being disposed on a wall surface of the fan close to the back end plate, the positioning protrusion being coplanar with the fan or being partially contained in the positioning groove.

2. The impact screwdriver according to claim 1, wherein: The motor further comprises a motor bearing, the motor bearing being sleeved on the motor shaft and being located on a side of the fan close to the back end plate; A bearing chamber is disposed on the positioning protrusion along the first direction a, and the motor bearing is disposed in the bearing chamber.

3. The impact screwdriver according to claim 2, wherein: A first half-cavity having a side opening toward the second protrusion is disposed on the first protrusion, and a second half-cavity having a side opening toward the first protrusion is disposed on the second protrusion, the first half-cavity and the second half-cavity being spliced to form the bearing chamber.

4. The impact screwdriver according to claim 3, wherein: At least one of the first half-cavity and the second half-cavity comprises a first accommodating portion and a second accommodating portion which are connected in a stepped manner, the first accommodating portion being used for accommodating an end portion of the motor shaft; The second accommodating portion is used for accommodating the motor bearing, and the second accommodating portion comprises a first stop surface and a first arc-shaped inner wall surface, the first stop surface being disposed perpendicularly to the first direction a and being used for stopping a rear end surface of the motor bearing, and the first arc-shaped inner wall surface being disposed around the first direction a and being used for stopping an outer wall surface of the motor bearing, and the first arc-shaped inner wall surface being connected with an end surface of the positioning protrusion.

5. The impact screwdriver according to claim 3, wherein: At least one of the first half-cavity and the second half-cavity comprises a third accommodating portion, a fourth accommodating portion and a fifth accommodating portion which are connected in sequence, the third accommodating portion being used for accommodating an end portion of the motor shaft; The fourth accommodating portion is used for accommodating the motor bearing, and the fourth accommodating portion comprises a second stop surface, a second arc-shaped inner wall surface and a third stop surface which are connected in a U-shaped manner, the second stop surface and the third stop surface being disposed perpendicularly to the first direction a, and the second stop surface and the third stop surface stopping a rear end surface and a front end surface of the motor bearing respectively, and the second arc-shaped inner wall surface being disposed around the first direction a and being used for stopping an outer wall surface of the motor bearing. The fifth accommodating portion comprises a third arc-shaped inner wall surface connected with the third abutting surface, and the third arc-shaped inner wall surface is connected with the end surface of the positioning protrusion.

6. The impact screwdriver according to claim 4 or 5, characterized in that, a first hollow groove is arranged on the first protrusion in a radial direction and communicates with the first half cavity; and / or a second hollow groove is arranged on the second protrusion in a radial direction and communicates with the second half cavity.

7. The impact screwdriver according to claim 6, characterized in that, the number of the first hollow grooves is plural, and the plural first hollow grooves are arranged on the first protrusion in a radial direction; the number of the second hollow grooves is plural, and the plural second hollow grooves are arranged on the second protrusion in a radial direction.

8. The impact screwdriver of claim 6, wherein, The first half shell is a left half shell, and the second half shell is a right half shell.

9. The impact screwdriver according to claim 1, characterized in that, an air port is arranged on the casing, and a projection of the positioning protrusion on a plane parallel to the first direction a at least partially overlaps with the air port.

10. The impact screwdriver according to claim 9, characterized in that, the number of the air ports is plural, and the plural air ports are arranged on the casing in a circumferential direction around the first direction a.

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