Power tool

Abstract

This invention provides a power tool that is resistant to damage upon drop. The power tool comprises: a resin housing having a motor housing, a battery holder, and a handle extending elongatedly in a direction substantially orthogonal to the front-rear direction between the motor housing and the battery holder; and a metal housing located in front of the motor housing, having a cylindrical portion and a protrusion. The cylindrical portion has a cylindrical shape extending in the front-rear direction and communicating with the interior of the motor housing. A final output shaft is partially housed in the cylindrical portion, and the cylindrical portion houses at least a portion of a power transmission mechanism and is connected to the motor housing by a threaded connection. The protrusion protrudes radially outward from the cylindrical portion. The protrusion has a second engaging portion that engages with a first engaging portion of the resin housing at a position further forward than the connection point between the motor housing and the cylindrical portion, and is located further downward than the first engaging portion.

Description

Technical Field

[0001] This disclosure relates to a power tool. Background Technology

[0002] Impact wrenches are known as a type of power tool. For example, the impact wrench described in Japanese Patent Application Publication No. 2025-33535 comprises: a metal housing (also called a hammer housing) that accommodates the base of the anvil; and a resin outer shell. The resin outer shell comprises: a long, narrow handle portion; a motor housing portion connected to one end of the handle portion; and a battery holder portion connected to the other end of the handle portion. The metal housing is connected to the motor housing portion. The metal housing and the motor housing portion are connected by a threaded connection. Summary of the Invention

[0003] Regarding impact wrenches with the aforementioned structure, if a user accidentally drops the wrench, causing the motor, which is a heavy object, to collide with the ground from its motor housing, a torque acting in the opposite direction to the torque acting on the motor housing acts on the battery, which is also a heavy object. For large impact wrenches, the motor and battery are also large structures, thus increasing this opposing torque. Therefore, a larger force acts on the connection between the metal housing and the motor housing, potentially causing damage. This problem is not limited to electric impact wrenches but is common to various power tools (e.g., impact screwdrivers) that possess: a resin housing with a long, narrow handle, a motor housing, and a battery holder connected to one end of the handle and the other end of the handle; and a metal housing connected to the motor housing. Therefore, it is desirable to provide power tools that are less susceptible to damage upon drop.

[0004] This specification discloses a power tool. The power tool can be configured to include: a motor; a rotatable output shaft; a power transmission mechanism connected to the motor in an actuating manner and configured to transmit the rotational driving force of the motor to the output shaft; a resin housing; and a metal housing. The resin housing may have a motor housing, a battery holder, and a handle. When the axial direction of the output shaft is defined as the front-rear direction, and the side containing the output shaft in the front-rear direction is defined as the front side, and the opposite side of the output shaft is defined as the rear side, the motor housing has a cylindrical shape extending in the front-rear direction and houses the motor. The battery holder holds a removable battery that serves as the power source for the motor. The handle extends elongatedly between the motor housing and the battery holder in a direction substantially orthogonal to the front-rear direction. The metal housing may be located at the front of the motor housing. The metal housing may have a cylindrical portion and a protrusion. The cylindrical portion has a cylindrical shape extending in the front-rear direction and communicating with the interior of the motor housing. The final output shaft is partially housed in the cylindrical portion, and the cylindrical portion houses at least a portion of the power transmission mechanism and is connected to the motor housing by a threaded connection. The protrusion protrudes radially outward from the cylindrical portion. It can be configured such that, when a direction orthogonal to the front-rear direction and substantially parallel to the length direction of the handle portion is defined as the vertical direction, and the side where the motor housing is located in the vertical direction is defined as the upper side and the side where the battery holder is located is defined as the lower side, the protrusion has a second engaging portion that engages with a first engaging portion of the resin housing at a position further forward than the connection position between the motor housing and the cylindrical portion. The second engaging portion may be located at a position further downward than the first engaging portion.

[0005] According to this power tool, even if the user drops the tool and it collides with the ground from the motor housing, causing a torque in the opposite direction to act on the battery and the motor housing, the first and second engaging parts can withstand the force acting in the direction that would damage the threaded connection between the cylindrical part of the metal housing and the motor housing (hereinafter also referred to as the force during the drop). Therefore, the threaded connection between the cylindrical part of the metal housing and the motor housing is unlikely to be damaged. Attached Figure Description

[0006] Figure 1 This is a perspective view of the impact wrench according to the first embodiment.

[0007] Figure 2 It is a 3D diagram of an impact wrench.

[0008] Figure 3 This is the front of the impact wrench.

[0009] Figure 4 This is the left view of an impact wrench.

[0010] Figure 5 It is along Figure 3 A cross-sectional view of an AA-line impact wrench.

[0011] Figure 6 This is a right view of the right side of the outer casing.

[0012] Figure 7 This is a 3D view of the hammer casing.

[0013] Figure 8 This is a right view of the hammer casing.

[0014] Figure 9 It is along Figure 4 A partial cross-sectional view of a BB line impact wrench.

[0015] Figure 10 yes Figure 9 A magnified view of a portion of the image.

[0016] Figure 11 It is along Figure 4 A partial cross-sectional view of an impact wrench with a CC line.

[0017] Figure 12 yes Figure 11 A magnified view of a portion of the image.

[0018] Figure 13 This diagram illustrates the torque exerted when an impact wrench falls.

[0019] Figure 14 This is a right view of the impact wrench according to the second embodiment.

[0020] Figure 15 This is a perspective view of the hammer housing according to the second embodiment.

[0021] Figure 16 This is a partial cross-sectional view of the impact wrench according to the second embodiment, and is consistent with... Figure 9 correspond.

[0022] Figure 17 yes Figure 16 A magnified view of a portion of the image.

[0023] Figure 18 This is a perspective view of the impact wrench according to the third embodiment.

[0024] Figure 19 It is a 3D diagram of an impact wrench.

[0025] Figure 20 This is the front of the impact wrench.

[0026] Figure 21 This is the left view of an impact wrench.

[0027] Figure 22 It is along Figure 20 A cross-sectional view of an impact wrench with a DD line.

[0028] Figure 23 yes Figure 22 A magnified view of a portion of the image.

[0029] Figure 24 This is a right view of the impact wrench and buffer after the protective cover has been removed.

[0030] Figure 25 It is a 3D view of the impact wrench and shock absorber after the protective cover has been removed.

[0031] Figure 26 It is along Figure 21 A partial cross-sectional view of an EE wire impact wrench.

[0032] Figure 27 It is along Figure 21 A partial cross-sectional view of an impact wrench with an FF line.

[0033] Figure 28 This is a 3D diagram of the buffer.

[0034] Figure 29 This is a 3D diagram of the buffer.

[0035] Figure 30 This is a right view of the hammer casing.

[0036] Figure 31 This is a perspective view of the buffer according to the fourth embodiment, showing the state after the protective cover has been removed.

[0037] Figure 32 This is a partial cross-sectional view of the impact wrench according to the fourth embodiment, and is consistent with... Figure 26 correspond.

[0038] Figure 33 This is a perspective view of the buffer according to the fourth embodiment.

[0039] Explanation of reference numerals in the attached figures

[0040] 10… Impact wrench; 15… Battery; 16… Lighting unit; 21… Motor; 22… Motor shaft; 23… Power transmission mechanism; 24… Reduction mechanism; 25… Spindle; 26… Striking mechanism; 27… Anvil; 28… Controller; 29… Trigger; 30… Hammer housing; 31… Cylindrical part; 32… Front protrusion; 33… Rear protrusion; 34… Threaded boss; 35… Screw; 36… Front base; 37… Front rib; 38… Upper surface; 39… Second front engagement part; 40… Rear base; 41… Rear rib; 42… Upper surface; 43… Second rear engagement part; 50… Housing; 50a… Right side portion; 50b… Left side portion; 51… Battery holder; 51a… Battery assembly part; 52… Handle portion; 52a…Upper end; 53…Support portion; 53a…Upper end; 54…Connecting portion; 55…Motor housing portion; 56a, 56b…Threaded boss; 57…Screw; 58…Gearbox; 59…Side handle; 60, 61…Recess; 62, 63…Upper inner surface; 64…Front first engaging portion; 65, 66…Recess; 67…Inner surface; 67, 68…Upper inner surface; 69…Rear first engaging portion; 90…First buffer; 91…Second buffer; 110…Impact wrench; 130…Hammer housing; 132…Front protrusion; 133…Rear protrusion; 136…Front base; 136a…Through hole; 137a…Upper rib; 137b…Lower rib; 138a, 138b…Upper… Surface; 139a…Upper second engaging portion; 139b…Lower second engaging portion; 156a, 156b…Threaded boss; 157…Screw; 160a, 160b, 161a, 161b…Recess; 162a, 162b, 163a, 163b…Upper inner surface; 164a…Upper first engaging portion; 164b…Lower first engaging portion; GR…Ground; AX1…Rotation axis; 210…Impact wrench; 230…Hammer housing; 231…Screw; 232…Annular recess; 233…First outer diameter portion; 233a…Front side; 234…Second outer diameter portion; 234a…Rear side; 235…Annular groove; 236…Bottom; 237…First protrusion; 237a…Top; 237b…side; 238…recess; 250…outer shell; 250a…first part; 250b…second part; 252…handle; 255…motor housing; 260…first buffer; 261…annular part; 261a…rear part; 261b…front part; 261c…inner circumferential surface; 262…protrusion; 262a…right wall; 262b…left wall; 262c…front wall; 263…first engaging part; 264…second protrusion; 265…annular groove; 266…second engaging part; 267…protrusion; 268…shaft; 269…head; 280…second buffer; 281…annular protrusion; 351…small diameter hole; 352…large diameter hole; 353…step; 355…hole;356…Small diameter bore; 356a…Threaded boss; 357…Large diameter bore; 410…Impact wrench; 455…Bore; 456…Small diameter bore; 457…Large diameter bore; 458…Stepped section; 460…First buffer; 466…Second engaging section; 467…Protrusion; 468…Shaft section; 469…Head. Detailed Implementation

[0041] The following detailed description of representative and non-limiting examples of the invention, with reference to the accompanying drawings, is intended merely to show details of preferred embodiments for carrying out the invention to those skilled in the art and is not intended to limit the scope of the invention. Furthermore, to provide further improved apparatus, methods of manufacturing, and methods of use, the following additional features and inventions may be used, either differently from or in conjunction with other features and inventions.

[0042] Furthermore, the features and combinations of processes disclosed in the following detailed description are not essential elements for carrying out the invention in the broadest sense, but are described merely to illustrate particularly representative examples of the invention. Moreover, the various features of the above and below representative examples, as well as the various features recited in the independent and dependent claims, are not necessarily required to be combined in the order of the examples or enumeration described herein when providing additional and useful embodiments of the invention.

[0043] All features described in this specification and / or claims are intended to differ from the structure of the embodiments and / or features described in the claims as limitations on the disclosure at the time of the application and on the specific matters claimed in the claims, and are disclosed separately and independently of each other. Furthermore, all descriptions relating to numerical ranges and groups or sets disclose their intermediate configurations as limitations on the disclosure at the time of the application and on the specific matters claimed in the claims.

[0044] In one or more embodiments, the protrusion may include: a base that protrudes downward from the lowest part of the cylindrical portion; and a cross-direction extension that extends from the base in a direction intersecting the vertical direction and has a second engaging portion. According to this structure, the power tool can be made compact in directions intersecting the front-back and vertical directions.

[0045] In one or more embodiments, the intersecting direction extension may extend in a direction orthogonal to the vertical direction. At least a portion of the upper surface of the intersecting direction extension may function as a second engaging portion. This structure facilitates the positioning of the metal housing and the resin outer shell, thereby facilitating the manufacture of power tools.

[0046] In one or more embodiments, the cross-direction extension can be configured such that, when the direction orthogonal to the front-back and up-down directions is defined as the left-right direction, the cross-direction extension extends from the base toward the right and left sides. According to this structure, the first and second engaging portions can evenly withstand the force of a fall on both sides. Therefore, the threaded joint between the cylindrical portion of the metal housing and the motor housing is less prone to damage.

[0047] In one or more embodiments, the resin outer shell may be configured such that it has a recess having a size and shape suitable for and accommodating the intersecting direction extensions. At least a portion of the downward-facing surface of the inner surface of the resin outer shell defining the recess can function as a first engaging portion. With this structure, positioning of the metal shell and the resin outer shell is easy. Furthermore, it is possible to suppress wobbling between the metal shell and the resin outer shell.

[0048] In one or more embodiments, the first and second engaging portions may be configured to engage through surface contact. According to this structure, compared to point or line contact, the first and second engaging portions can stably withstand the force of a fall over a larger area.

[0049] In one or more embodiments, the second engaging portion may be positioned in the front-rear direction corresponding to the front half of the metal housing. According to this structure, the engaging portions of the first and second engaging portions are far from the threaded connection between the cylindrical portion of the metal housing and the motor housing portion, thus increasing the torque in the direction of the force exerted during a fall. Therefore, the load that the first and second engaging portions should bear during a fall can be reduced.

[0050] In one or more embodiments, the resin housing may further include a support column located further forward than the handle portion and extending in an elongated shape, substantially parallel to the handle portion, between the battery holder and the metal housing. A first engaging portion may be located at the end of the support column opposite to the battery holder. According to this structure, the durability of the power tool in the event of a drop can be improved by utilizing the support column. In other words, it is possible to make the power tool larger. Furthermore, the more forward position of the support column secures the first engaging portion. Therefore, the load that the first and second engaging portions should bear in the event of a drop can be further reduced.

[0051] In one or more embodiments, the first engaging portion may include a front first engaging portion and a rear first engaging portion, which is separated from the front first engaging portion in the front-rear direction and located further rearward than the front first engaging portion. The second engaging portion may include a front second engaging portion that engages with the front first engaging portion and a rear second engaging portion, which is separated from the front second engaging portion in the front-rear direction, located further rearward than the front second engaging portion, and engages with the rear first engaging portion. According to this structure, the first and second engaging portions can withstand the force of a drop at two points where they are separated in the front-rear direction. That is, the number of points that withstand the force of a drop is increased. Therefore, the threaded joint between the cylindrical portion of the metal housing and the motor housing is less susceptible to damage.

[0052] In one or more embodiments, the first engaging portion may include an upper first engaging portion and a lower first engaging portion, which is separated from the upper first engaging portion in the vertical direction and is located at a lower position than the upper first engaging portion. The cross-direction extension may include an upper second engaging portion that engages with the upper first engaging portion and a lower second engaging portion, which is separated from the upper second engaging portion in the vertical direction, is located at a lower position than the upper second engaging portion, and engages with the lower first engaging portion. According to this structure, the first engaging portion and the second engaging portion can withstand the force of a drop at two locations that are separated in the vertical direction. That is, the number of locations that withstand the force of a drop is increased. Therefore, the threaded joint of the cylindrical portion of the metal housing and the motor housing is less likely to be damaged.

[0053] In one or more embodiments, the resin housing can be configured such that it has a bi-half-segment structure capable of separating into a right side portion and a left side portion in directions orthogonal to the front-back and vertical directions. The power tool can include multiple screws that connect the right and left sides. Each screw can connect the right and left sides without penetrating through a protrusion. According to this structure, the force of a fall does not act on any of the screws. Therefore, it is unnecessary to design any of the screws to withstand the force of a fall. That is, the specifications of the screws can be standardized, reducing the manufacturing time of the power tool.

[0054] In one or more embodiments, the resin housing may be configured to have a bi-half-part structure capable of separating into a right side portion and a left side portion in directions orthogonal to the front-back and vertical directions. The power tool may include multiple screws that engage the right side and left side portions. At least one of the screws can engage the right side and left side portions with its protrusion through. According to this structure, in addition to the first and second engaging portions, the screw with the protrusion through can also withstand the force of a fall. Therefore, the threaded connection between the cylindrical portion of the metal housing and the motor housing is less susceptible to damage.

[0055] This specification discloses an electric tool. The electric tool may include: a motor; a final output shaft rotatable about a rotation axis; a power transmission mechanism connected to the motor in an actuating manner and configured to transmit the rotational driving force of the motor to the final output shaft; a metal housing; a protective cover; and a resin housing. The metal housing may be configured such that it has a cylindrical shape extending in the axial direction along the rotation axis, the final output shaft is partially housed within the metal housing, and the metal housing houses at least a portion of the power transmission mechanism. The protective cover may be configured such that, when the axial direction is defined as the front-rear direction, the side where the final output shaft is located in the front-rear direction is defined as the front side, and the opposite side of the final output shaft is defined as the rear side, the protective cover covers the front portion of the metal housing about the rotation axis. The protective cover may be mounted to the metal housing in a manner detachable from the front side. The resin housing may be adjacent to the metal housing in a direction orthogonal to the axial direction. The protective cover may have an annular portion and a protrusion. The annular portion can be configured such that it has a first engaging portion that can be detachably engaged with a metal housing using the elasticity of a protective cover, and covers the metal housing about a rotation axis. The protrusion can be configured such that it has a second engaging portion that can be detachably engaged with a resin housing using the elasticity of a protective cover, and protrudes radially outward from the annular portion. The hammer housing 230 described later is a non-limiting example of a "metal housing". The first buffer 260 described later is a non-limiting example of a "protective cover". The support portion 53 described later is a non-limiting example of a "resin housing".

[0056] According to this power tool, in addition to the metal housing, the protective cover also engages with a resin outer shell adjacent to the metal housing in a direction orthogonal to the axial direction. Therefore, compared to a structure where the protective cover only engages with the metal housing, accidental peeling of the protective cover can be prevented.

[0057] In one or more embodiments, the resin housing may be configured to have a hole. The second engaging portion may have a protrusion that is inserted into the hole and engages with the inner surface of the resin housing that defines the hole. According to this structure, the protective cover can be easily attached and detached by pressing the protrusion of the second engaging portion into the hole of the resin housing and by pulling the protrusion of the second engaging portion out of the hole of the resin housing. The threaded boss 356a, hole 355, and hole 455 described later are non-limiting examples of "hole".

[0058] In one or more embodiments, the hole may be configured such that it comprises: a small-diameter hole having a first inner diameter; and a large-diameter hole having a second inner diameter greater than the first inner diameter, and is continuous with the small-diameter hole at a position closer to the inside of the resin housing than the small-diameter hole. The protrusion may comprise: a shaft having an outer diameter smaller than the first inner diameter; and a head having an outer diameter greater than the first inner diameter and smaller than the second inner diameter, located at the end of the shaft. The head of the protrusion, inserted into the large-diameter hole, can engage with the step portion between the small-diameter hole and the large-diameter hole in a manner that prevents it from falling out of the hole. According to this structure, the protrusion of the second engaging portion of the protective cover can be securely engaged with the hole in the resin housing. Therefore, accidental peeling of the protective cover can be further suppressed.

[0059] In one or more embodiments, the resin housing may be configured to have a split structure capable of being separated into a first part and a second part. The opening may include a threaded boss for inserting a screw to engage the first and second parts. According to this configuration, the threaded boss for engaging the first and second parts of the resin housing can also be used as an opening for engaging with a protective cover. Therefore, the structure of the resin housing can be simplified compared to a structure where the opening and the threaded boss are separate. The threaded boss 356a described later is a non-limiting example of a "threaded boss".

[0060] In one or more embodiments, the metal housing may include: a first outer diameter portion having a first outer diameter; a second outer diameter portion located further forward than the first outer diameter portion and having a second outer diameter smaller than the first outer diameter; and an annular groove portion located between the first outer diameter portion and the second outer diameter portion. The annular groove portion may include: a bottom; and a plurality of first protrusions projecting radially outward from the bottom and arranged circumferentially spaced apart. The tops of the plurality of first protrusions may be located radially further inward than the outer periphery of the second outer diameter portion. The first engaging portion may include a plurality of second protrusions arranged circumferentially spaced apart, each elastically deformed and suitably inserted into a plurality of recesses defined between the plurality of first protrusions, engaging with the inner surface of the defined recesses in a manner that prevents it from falling out of the recesses. The annular portion is clamped in the front-rear direction by the first and second outer diameter portions while the plurality of second protrusions are respectively inserted into the plurality of recesses. According to this structure, in addition to the engagement based on multiple second protrusions, the metal housing and the protective cover are further engaged by clamping an annular portion in the front-rear direction using the first and second outer diameter portions. Furthermore, in the circumferential direction where no second protrusions are present, the annular portion of the protective cover is also deeply embedded in the annular groove between the first and second outer diameter portions. Therefore, the engagement force is increased, further suppressing accidental peeling of the protective cover.

[0061] In one or more embodiments, the resin housing may include: a battery holder configured to hold a removable battery that serves as a power source for the motor; a handle located between the battery holder and the metal housing in a direction orthogonal to the axial direction, extending in an elongated shape in a direction substantially orthogonal to the axial direction; and a support portion located further forward than the handle, extending in an elongated shape between the battery holder and the metal housing, substantially parallel to the handle. A second engaging portion can engage with the support portion.

[0062] The following is for reference Figures 1-13 The impact wrench 10 according to the representative and non-limiting first embodiment of this disclosure will be described in more detail. For example... Figures 1-5 As shown, the impact wrench 10 has a metal hammer housing 30 and a resin outer shell 50. (As indicated...) Figure 6 As shown, the housing 50 includes a battery holding part 51, a handle part 52, a support part 53, a connecting part 54, and a motor housing part 55.

[0063] like Figure 5As shown, the motor housing 55 has a cylindrical shape and houses the motor 21, which has a motor shaft 22. A power transmission mechanism 23 is connected to the motor shaft 22 in an actuating manner. The power transmission mechanism 23 transmits the rotational driving force of the motor 21 to the anvil 27, which serves as the final output shaft. Thus, the anvil 27 can rotate about a rotation axis AX1. The rotation axis AX1 is coaxial with respect to the motor shaft 22 and coincides with the central axis of the anvil 27. The power transmission mechanism 23 includes a reduction mechanism 24, a main shaft 25, and a striking mechanism 26. The striking mechanism 26 provides a striking force in the rotational direction to the anvil 27. This mechanical structure of the impact wrench 10 is well known, therefore, a detailed description is omitted here.

[0064] like Figure 5 As shown, a gearbox 58 is disposed adjacent to the motor housing 55 and holds the reduction mechanism 24. A hammer housing 30 is disposed adjacent to the gearbox 58 on its front side. The hammer housing 30 has a cylindrical shape extending along the axial direction of the anvil 27 (the direction in which the rotation axis AX1 extends), and its interior communicates with the interior of the motor housing 55. A main shaft 25 and a striking mechanism 26 are housed within the hammer housing 30. Furthermore, the anvil 27 is partially housed within the hammer housing 30. The front end of the anvil 27 protrudes from the hammer housing 30.

[0065] like Figures 1-5 As shown, the handle portion 52 extends elongatedly between the motor housing portion 55 and the battery holding portion 51 in a direction intersecting (more specifically, approximately orthogonal) the rotation axis AX1. The handle portion 52 is the part held by the user when using the impact wrench 10. The battery holding portion 51 has a battery mounting portion 51a on the edge opposite to the handle portion 52. The battery mounting portion 51a has: an interface for electrically connecting to the battery 15, which serves as the power source for the impact wrench 10; and an interface for mechanically connecting to the battery 15, and is configured to detachably mount the battery 15. The battery holding portion 51 holds the battery 15 mounted in the battery mounting portion 51a.

[0066] For ease of explanation, the direction in which the rotation axis AX1 extends is defined as the front-rear direction of the impact wrench 10. In the front-rear direction, the side where the anvil 27 is located is defined as the front side of the impact wrench 10, and its opposite side is defined as the rear side of the impact wrench 10. Furthermore, the direction orthogonal to the rotation axis AX1 and approximately parallel to the extension direction of the handle portion 52 (in other words, the length direction of the handle portion 52) is defined as the vertical direction of the impact wrench 10. In the vertical direction, the side where the motor housing portion 55 (or hammer housing 30) is located is defined as the upper side of the impact wrench 10, and the side where the battery holder portion 51 is located is defined as the lower side of the impact wrench 10. Moreover, the direction orthogonal to both the front-rear and vertical directions is defined as the left-right direction of the impact wrench 10. In the left-right direction, the right side when viewing the front from the rear is defined as the right side of the impact wrench 10, and its opposite side is defined as the left side of the impact wrench 10.

[0067] like Figures 1-5 As shown, a trigger 29 for starting and stopping the motor 21 is provided on the upper and front part of the handle portion 52. Figure 5 As shown, a controller 28 is housed within the battery holding section 51. The controller 28 supplies power from the battery 15 to the motor 21 to control the operation of the motor 21.

[0068] like Figures 1-6 As shown, the handle portion 52 extends upward from near the rear edge of the battery holder portion 51. The upper and rear edges of the handle portion 52 are continuous with the motor housing portion 55. The support portion 53 is located further forward than the handle portion 52 and extends in a strip shape, substantially parallel to the handle portion 52, between the front edge of the battery holder portion 51 and the hammer housing 30. In other words, the support portion 53 is adjacent to the hammer housing 30 in the vertical direction. The connecting portion 54 extends in the front-rear direction and connects the upper end of the support portion 53 and the upper end of the handle portion 52 below the hammer housing 30.

[0069] like Figures 1-4 As shown, in this embodiment, the outer casing 50 has a bi-half-part structure that can be separated in the left-right direction into a right side portion 50a and a left side portion 50b. The right side portion 50a and the left side portion 50b are both integrally molded. Figure 1 and Figure 6 As shown, the right portion 50a has multiple threaded bosses 56a. The threaded bosses 56a open to the right. The left portion 50b also has multiple threaded bosses 56b opening to the right at positions corresponding to the multiple threaded bosses 56a of the right portion 50a (see reference). Figure 5 and Figure 9The right side portion 50a and the left side portion 50b are integrated by means of multiple screws 57 inserted into multiple threaded bosses 56a and 56b respectively.

[0070] like Figures 1-3 As shown, the side handle 59 can be mounted on the impact wrench 10. In Figures 1-3 The side handle 59 was removed from the attached diagram. Figure 1 and Figure 3 As shown, a ring-shaped lighting unit 16 is arranged on the front side of the hammer housing 30. The lighting unit 16 has a plurality of LEDs distributed in a circumferential direction about the rotation axis AX1. The lighting unit 16 illuminates light towards the front when the impact wrench 10 is used.

[0071] like Figures 1-5 As shown, a first buffer 90 and a second buffer 91, serving as protective covers, are installed on the hammer housing 30. The first buffer 90 and the second buffer 91 are formed of an elastic material. In this embodiment, the first buffer 90 and the second buffer 91 are formed of rubber. The first buffer 90 is installed on the upper end 53a of the hammer housing 30 and the support portion 53 in a manner that allows it to be detached from the front. The first buffer 90 covers the front portion of the hammer housing 30 about the rotation axis AX1. The second buffer 91 is detachably installed on the front edge of the hammer housing 30. The second buffer 91 covers the front edge of the hammer housing 30 about the rotation axis AX1.

[0072] like Figure 7 and Figure 8 As shown, the hammer housing 30 includes a cylindrical portion 31, a front protrusion 32, and a rear protrusion 33. The cylindrical portion 31 has an approximately cylindrical shape extending in the front-rear direction. As described above, a main shaft 25 and a striking mechanism 26 are housed within the cylindrical portion 31. Figures 1-4 As shown in Figures 7 and 8, the cylindrical portion 31 has four threaded bosses 34 on its rear edge. The four threaded bosses 34 are distributed circumferentially about the rotation axis AX1. The cylindrical portion 31 is connected to the motor housing portion 55 by means of these threaded bosses 34 and by threaded engagement. Specifically, the motor housing portion 55 and the cylindrical portion 31 are fastened together by four screws 35 inserted into the four threaded bosses 34, thereby integrating them into one unit.

[0073] like Figure 7 and Figure 8As shown, the front protrusion 32 and the rear protrusion 33 protrude radially outward from the cylindrical portion 31 at a position further forward than the connection point between the motor housing 55 and the cylindrical portion 31. The front protrusion 32 and the rear protrusion 33 are separated in the front-rear direction. In the front-rear direction, the front protrusion 32 is positioned corresponding to the front half of the hammer housing 30, and the rear protrusion 33 is positioned corresponding to the rear half. More specifically, the front protrusion 32 is located near the front edge of the cylindrical portion 31, and the rear protrusion 33 is partially located further forward than the threaded boss 34.

[0074] like Figure 7 and Figure 8 As shown, the front protrusion 32 includes a front base 36 and a front rib 37. The front base 36 protrudes downward from the lowest part of the cylindrical portion 31. The front rib 37 extends from the front base 36 in a direction intersecting the vertical direction. In this embodiment, the front rib 37 extends from the front base 36 in a direction orthogonal to the vertical direction (left-right direction). Furthermore, the front rib 37 includes a portion extending to the right from the front base 36 and a portion extending to the left from the front base 36.

[0075] like Figure 9 and Figure 10 As shown, the upper end portion 53a of the support portion 53 has recesses 60 and 61. More specifically, the portion forming the upper end portion 53a in the right portion 50a has a recess 60, and the portion forming the upper end portion 53a in the left portion 50b has a recess 61. The recesses 60 and 61 open toward the interior of the upper end portion 53a in the left-right direction. The recess 60 has a size and shape suitable for the right side portion of the front rib 37 of the front protrusion 32, and the recess 61 has a size and shape suitable for the left side portion of the front rib 37. The front rib 37 is received within the recesses 60 and 61.

[0076] In this embodiment, the front rib 37 is received within the recesses 60 and 61 in such a manner that it abuts against the upper and lower inner surfaces of the recesses 60 and 61. That is, the front rib 37 is fitted into the recesses 60 and 61. Therefore, the upper surface 38 of the front rib 37 is always engaged (abutting) against the upper inner surface 62 of the recess 60 and the upper inner surface 63 of the recess 61 in the vertical direction. The upper inner surfaces 62 and 63 are downward-facing surfaces. The portion of the upper inner surfaces 62 and 63 that engages with the upper surface 38 of the front rib 37 is also referred to as the first front engagement portion 64. The portion of the upper surface 38 of the front rib 37 that engages with the upper inner surfaces 62 and 63 is also referred to as the second front engagement portion 39. The second front engagement portion 39 is located at a lower position than the first front engagement portion 64. The first engaging part 64 and the second engaging part 39 on the front side engage through surface contact.

[0077] like Figure 9 and Figure 10 As shown, the front protrusion 32 is located higher than the uppermost threaded bosses 56a and 56b of the support portion 53. Therefore, none of the screws 57 that connect the right portion 50a and the left portion 50b penetrate the front protrusion 32. The same applies to the rear protrusion 33, which will be described later.

[0078] like Figure 7 and Figure 8 As shown, the rear protrusion 33 includes a rear base 40 and a rear rib 41. The rear base 40 protrudes downward from the lowest part of the cylindrical portion 31. The rear rib 41 extends from the rear base 40 in a direction intersecting the vertical direction. In this embodiment, the rear rib 41 extends from the rear base 40 in a direction orthogonal to the vertical direction (left-right direction). Furthermore, the rear rib 41 includes: a portion extending to the right from the rear base 40; and a portion extending to the left from the rear base 40 (in...). Figure 7 and Figure 8 In the middle, only the portion extending to the right from the rear base 40 is visible.

[0079] like Figure 11 and Figure 12 As shown, the upper end portion 52a of the handle portion 52 has recesses 65 and 66. More specifically, the portion forming the upper end portion 52a in the right side portion 50a has a recess 65, and the portion forming the upper end portion 52a in the left side portion 50b has a recess 66. The recesses 65 and 66 open toward the interior of the upper end portion 52a in the left-right direction. The recess 65 has a size and shape suitable for the right side portion of the rear rib 41 of the rear protrusion 33, and the recess 66 has a size and shape suitable for the left side portion of the rear rib 41. The rear rib 41 is received within the recesses 65 and 66.

[0080] In this embodiment, the rear rib 41 is received within the recesses 65 and 66 in such a manner that it abuts against the upper and lower inner surfaces of the recesses 65 and 66. That is, the rear rib 41 is fitted into the recesses 65 and 66. Therefore, the upper surface 42 of the rear rib 41 is always engaged (abutting) against the upper inner surface 67 of the recess 65 and the upper inner surface 68 of the recess 66 in the vertical direction. The upper inner surfaces 67 and 68 are downward-facing surfaces. The portion of the upper inner surfaces 67 and 68 that engages with the upper surface 42 of the rear rib 41 is also referred to as the first rear engagement portion 69. The portion of the upper surface 42 of the rear rib 41 that engages with the upper inner surfaces 67 and 68 is also referred to as the second rear engagement portion 43. The second rear engagement portion 43 is located at a lower position than the first rear engagement portion 69. The first engaging part 69 and the second engaging part 43 on the rear side engage through surface contact.

[0081] Regarding the aforementioned impact wrench 10, as Figure 13 As shown, when the impact wrench 10 falls from the motor housing 55 and collides with the ground GR, a torque in the direction indicated by arrow AR1 acts on the motor housing 55, which houses the motor 21 as a weight. On the other hand, a torque acts on the battery 15, which is also a weight, in the direction indicated by arrow AR2, opposite to arrow AR1. Due to this torque in the opposite direction, a larger force (the force exerted during the fall) acts on the connection between the hammer housing 30 based on the screw 35 and the motor housing 55, which may cause damage to this connection.

[0082] However, according to the impact wrench 10, such damage to the connection part can be suppressed. Specifically, when the force of the fall is applied, the downward force acts on the upper end 53a of the support portion 53, and the upward force acts on the front protrusion 32 of the hammer housing 30. The front first engaging portion 64 of the upper end 53a of the support portion 53 of the housing 50 and the front second engaging portion 39 of the front protrusion 32 of the hammer housing 30 engage in the vertical direction, with the front second engaging portion 39 located lower than the front first engaging portion 64. Therefore, the front first engaging portion 64 and the front second engaging portion 39 can withstand the force of the fall acting in the aforementioned directions. As a result, damage to the connection part can be suppressed.

[0083] Similarly, when the force of a fall is applied, the downward force acts on the upper end 52a of the handle portion 52, and the upward force acts on the rear protrusion 33 of the hammer housing 30. Therefore, the rear first engaging portion 69 and the rear second engaging portion 43 can withstand the force of a fall acting in the aforementioned directions. According to this structure, the force of a fall can be absorbed at two separate locations in the front-rear direction (the engaging portion of the front first engaging portion 64 and the front second engaging portion 39, and the engaging portion of the rear first engaging portion 69 and the rear second engaging portion 43). That is, the number of locations that absorb the force of a fall is increased. Therefore, the connecting parts are less likely to be damaged.

[0084] Furthermore, according to the front protrusion 32, the front base 36 protrudes downward from the lowest part of the cylindrical portion 31, and the front rib 37, having the front second engaging portion 39, extends from the front base 36 in a direction intersecting the vertical direction. Therefore, the impact wrench 10 can be made compact in the left-right direction. In addition, the same effect can be obtained by using the rear protrusion 33.

[0085] Furthermore, based on the front protrusion 32, the front rib 37, which has a front second engaging portion 39, extends in a direction orthogonal to the vertical direction. Additionally, the upper surface 38 of the front rib 37 functions as the front second engaging portion 39. Therefore, positioning of the hammer housing 30 and the outer casing 50 is easy, thereby facilitating the manufacture of the impact wrench 10. The same effect can also be achieved using the rear protrusion 33.

[0086] Furthermore, according to the front protrusion 32, the front rib 37 extends from the front base 36 toward the right and left sides. Therefore, the front first engaging portion 64 and the front second engaging portion 39 can evenly withstand the force of a fall in the left and right directions. As a result, the joint is less likely to be damaged. In addition, the same effect can be achieved by using the rear protrusion 33.

[0087] Furthermore, according to the impact wrench 10, the upper end portion 53a of the support portion 53 has recesses 60 and 61 that receive the front rib 37 of the front protrusion 32, and the upper inner surfaces 62 and 63 of the recesses 60 and 61 function as the front first engaging portion 64. Therefore, it is easy to position the hammer housing 30 and the outer shell 50. In addition, it is possible to suppress wobbling between the hammer housing 30 and the outer shell 50. In addition, the same effect can be obtained by using the recesses 65 and 66 of the handle portion 52.

[0088] Furthermore, according to the impact wrench 10, the front first engaging portion 64 and the front second engaging portion 39 engage through surface contact. Therefore, compared to point contact or line contact, the front first engaging portion 64 and the front second engaging portion 39 can stably withstand the force of a fall over a larger area.

[0089] Furthermore, according to the impact wrench 10, the front protrusion 32 is positioned in the front-rear direction corresponding to the front half of the hammer housing 30. Therefore, the engaging portions of the front first engaging portion 64 and the front second engaging portion 39 are far from the engagement portion based on the screw 35, thus increasing the torque in the direction of the force exerted upon falling. Therefore, the load that the front first engaging portion 64 and the front second engaging portion 39 should bear upon falling can be reduced. Moreover, the front first engaging portion 64 is provided at the upper end 53a of the support portion 53, which is located further forward than the handle portion 52, thus allowing the engaging portions of the front first engaging portion 64 and the front second engaging portion 39 to be positioned even further forward. Therefore, the load that the front first engaging portion 64 and the front second engaging portion 39 should bear upon falling can be further reduced.

[0090] Furthermore, according to the impact wrench 10, none of the multiple screws 57 that connect the right side portion 50a and the left side portion 50b of the housing 50 penetrate the front protrusion 32 and the rear protrusion 33. Therefore, it is not necessary to design any of the multiple screws 57 to withstand the force of a fall. That is, the specifications of the multiple screws 57 can be made common, thereby reducing the manufacturing time of the impact wrench 10.

[0091] Hereinafter, regarding the impact wrench 110 according to the second embodiment, refer to Figures 14-17 Only the differences relative to the first embodiment will be described. Figures 14-17 In this document, structural elements identical to those in the first embodiment are labeled with the same reference numerals as those in the first embodiment. For example... Figure 14 As shown, regarding the impact wrench 110, the shape of the first buffer 90 differs from that of the first embodiment, resulting in the threaded boss 56a and screw 57 located at the upper end 53a of the support portion 53 being exposed to the outside. In the drawings, the threaded boss 56a and screw 57 located at the upper end 53a are shown as the threaded boss 156a and screw 157, respectively.

[0092] The impact wrench 110 replaces the hammer housing 30 of the first embodiment and has a hammer housing 130. For example... Figure 15 As shown, the hammer housing 130 has a front protrusion 132 and a rear protrusion 133. Although the rear protrusion 133 differs slightly in position and size from the rear protrusion 33 in the first embodiment, it has the same function as the rear protrusion 33. Therefore, the description of the rear protrusion 133 is omitted.

[0093] like Figure 15As shown, the front protrusion 132 includes a front base 136, an upper rib 137a, and a lower rib 137b. The front base 136 protrudes downward from the lowest part of the cylindrical portion 31. The upper rib 137a extends from the front base 136 between its upper and lower ends in a direction intersecting the vertical direction. In this embodiment, the upper rib 137a extends from the front base 136 in a direction orthogonal to the vertical direction (left-right direction). Furthermore, the upper rib 137a includes a portion extending to the right from the front base 136 and a portion extending to the left from the front base 136. The lower rib 137b extends from the lower end of the front base 136 in a direction intersecting the vertical direction. In this embodiment, the lower rib 137b extends from the front base 136 in a direction orthogonal to the vertical direction (left-right direction). Additionally, the lower rib 137b includes a portion extending to the right from the front base 136 and a portion extending to the left from the front base 136. The front base 136 has a through hole 136a between the upper rib 137a and the lower rib 137b in the vertical direction. The through hole 136a passes through the front base 136 in the horizontal direction.

[0094] like Figure 16 and Figure 17 As shown, the upper end portion 53a of the support portion 53 has recesses 160a, 160b, 161a, and 161b. More specifically, the portion forming the upper end portion 53a in the right portion 50a has recesses 160a and 160b, and the portion forming the upper end portion 53a in the left portion 50b has recesses 161a and 161b. Recesses 160a, 160b, 161a, and 161b open toward the interior of the upper end portion 53a in the left-right direction. Recess 160a is located higher than recess 160b, and recess 161a is located higher than recess 161b. Recesses 160a and 160b are respectively sized and shaped to fit the right side portions of the upper rib 137a and lower rib 137b of the front protrusion 132, and recesses 161a and 161b are respectively sized and shaped to fit the left side portions of the upper rib 137a and lower rib 137b. The upper rib 137a is received within recesses 160a and 161a, and the lower rib 137b is received within recesses 160b and 161b.

[0095] Similar to the first embodiment, the upper surface 138a of the upper rib 137a engages in the vertical direction with the upper inner surface 162a of the recess 160a and the upper inner surface 163a of the recess 161a. Similarly, the upper surface 138b of the lower rib 137b engages in the vertical direction with the upper inner surface 162b of the recess 160b and the upper inner surface 163b of the recess 161b. The portion of the upper inner surfaces 162a and 163a that engages with the upper surface 138a of the upper rib 137a is also referred to as the upper first engaging portion 164a. The portion of the upper surface 138a that engages with the upper inner surfaces 162a and 163a is also referred to as the upper second engaging portion 139a. Similarly, in the upper inner surfaces 162b and 163b, the portion that engages with the upper surface 138b of the lower rib 137b is also referred to as the lower first engaging portion 164b. In the upper surface 138b, the portion that engages with the upper inner surfaces 162b and 163b is also referred to as the lower second engaging portion 139b.

[0096] like Figure 16 and Figure 17 As shown, the right end of the threaded boss 156b of the left portion 50b, corresponding to the threaded boss 156a of the right portion 50a, is inserted into the through hole 136a of the front protrusion 132. Therefore, the screw 157, which connects the right portion 50a and the left portion 50b, passes through the through hole 136a and penetrates the front protrusion 132 in the left-right direction.

[0097] According to the aforementioned impact wrench 110, the force of a fall can be withstood at two points that separate in the vertical direction (the engagement points of the upper first engagement portion 164a and the upper second engagement portion 139a, and the engagement points of the lower first engagement portion 164b and the lower second engagement portion 139b). That is, the number of points that can withstand the force of a fall is increased. Therefore, the threaded connection between the hammer housing 130 and the motor housing 55 is less likely to be damaged.

[0098] Furthermore, according to the impact wrench 110, the screw 157 located at the upper end 53a of the support portion 53 engages the right portion 50a and the left portion 50b while the front protrusion 132 is penetrated. With this structure, the screw 157 penetrating the front protrusion 132 and the threaded boss 156b can also additionally withstand the force of a fall between themselves and the inner surface of the front protrusion 132 that defines the through hole 136a. Therefore, the threaded connection between the hammer housing 130 and the motor housing 55 is less prone to damage.

[0099] The first and second embodiments described above are provided for easy understanding of the present invention and are not intended to limit the invention. The present invention can be modified and improved without departing from its spirit, and its equivalents are included. Furthermore, within the scope of solving at least a portion of the above-mentioned problems or achieving at least a portion of the effects, the structural elements described in the claims and specification can be arbitrarily combined or omitted.

[0100] For example, as long as the second engaging portion of the hammer housing 30 is located lower than the first engaging portion of the outer casing 50, and both the first and second engaging portions can withstand the force of a fall, the position and shape of the protrusions 32 and 33 can be arbitrarily changed. The same applies to the front protrusions 132 and 133. Furthermore, the position and shape of the outer casing 50 (first engaging portion) can also be arbitrarily changed based on the position and shape of the protrusions 32 and 33. For example, the protrusion 32 can protrude from the cylindrical portion 31 in a direction that forms an angle with respect to the vertical direction. Alternatively, the front rib 37 can extend from the front base 36 in a direction that does not intersect the vertical direction at a right angle. Alternatively, the front rib 37 can replace the left-right direction or extend in the front-back direction in addition to the left-right direction; for example, it can extend from the front base 36 in a flange-like shape.

[0101] Furthermore, the hammer housing 30 may only have one of the protrusions 32 and 33, and the hammer housing 130 may only have one of the front protrusions 132 and 133. Additionally, the front protrusion 132 may only have one of the upper rib 137a and the lower rib 137b. Alternatively, the front protrusion 132 may be deformed such that there is no through hole 136a between the upper rib 137a and the lower rib 137b. In this case, the screw 157 engages the right side portion 50a and the left side portion 50b at a position lower than the front protrusion 132.

[0102] Furthermore, the front rib 37 of the front protrusion 32 can be received within the recesses 60 and 61 with a slight gap in the vertical direction. Using this structure, after the housing 50 flexes accordingly with the gap, the front first engaging portion 64 and the front second engaging portion 39 engage, thereby, as in the embodiment described above, suppressing damage to the threaded joints of the hammer housing 130 and the motor housing 55. This also applies to the protrusions 33, 132, and 133.

[0103] The above-described embodiments are not limited to impact wrenches, but can be applied to various power tools (such as impact screwdrivers) with metal housings.

[0104] The following illustrates the correspondence between the structural elements of the above embodiments and the structural elements of the claims. However, each structural element of the embodiments is merely an example and does not limit the structural elements of the present invention. The impact wrench 10 is an example of a "power tool". The anvil 27 is an example of a "final output shaft". The hammer housing 30 is an example of a "metal housing". The support portion 53 is an example of a "resin housing". The front rib 37, rear rib 41, upper rib 137a, and lower rib 137b are examples of "cross-direction extensions".

[0105] The following is for reference Figures 18-30 The impact wrench 210 according to a representative and non-limiting third embodiment of this disclosure will be described in more detail. In the following description (including the drawings), structural elements labeled with the same reference numerals as those used to label structural elements of the first or second embodiment have the same structure as the corresponding structural elements of the first or second embodiment, and therefore descriptions are sometimes omitted. For example... Figures 18-22 As shown, the impact wrench 210 includes a metal hammer housing 230 and a resin outer shell 250. The outer shell 250 includes a battery holder 51, a handle 252, a support 53, a connecting part 54, and a motor housing 255.

[0106] like Figure 22 As shown, the motor housing 255 has a cylindrical shape and houses a motor 21 with a motor shaft 22.

[0107] like Figure 22 As shown, a gearbox 58 for holding the reduction gear 24 is disposed adjacent to the motor housing 255. A hammer housing 230 is disposed adjacent to the gearbox 58. The hammer housing 230 has the same structure as the hammer housing 30 of the first embodiment. The motor housing 255, gearbox 58, and hammer housing 230 are fastened together using four screws 231 extending parallel to the rotation axis AX1, thus achieving a unified structure. Figure 18 and Figure 19 As shown, four screws 231 are distributed circumferentially about the axis of rotation AX1.

[0108] The handle 252 has the same structure as the handle portion 52 in the first embodiment. For example... Figures 18-22 As shown, the handle 252 extends in a long strip along a direction intersecting (more specifically, approximately orthogonal) the rotation axis AX1. The handle 252 is the part held by the user when using the impact wrench 210. The handle 252 is located between the hammer housing 230 and the battery holder 51 in a direction orthogonal to the rotation axis AX1.

[0109] like Figures 18-21As shown, in this embodiment, the outer casing 250 has a split structure that allows it to be separated into a first portion 250a and a second portion 250b. The first portion 250a and the second portion 250b have the same structure as the right portion 50a and the left portion 50b in the first embodiment.

[0110] like Figures 18-22 As shown, a first buffer 260 and a second buffer 280, serving as protective covers, are installed on the hammer housing 230. The first buffer 260 and the second buffer 280 are formed of an elastic material. In this embodiment, the first buffer 260 and the second buffer 280 are formed of rubber. Although described in detail later, the first buffer 260 is installed on the hammer housing 230 and the support portion 53 in a manner that allows for detachment from the front. In its installed state, the first buffer 260 covers the front portion of the hammer housing 230 about the rotation axis AX1.

[0111] The second buffer 280 covers the leading edge of the hammer housing 230 about the rotation axis AX1. The second buffer 280 has an annular protrusion 281 that protrudes radially inward. The hammer housing 230 has an annular recess 232 at its leading end. The second buffer 280 is detachably mounted to the leading edge of the hammer housing 230 by inserting the annular protrusion 281 into the annular recess 282.

[0112] like Figure 23 As shown, the first buffer 260 and the second buffer 280 cover the front end face of the hammer housing 230 on the radially outer and inner sides of the lighting unit 16, respectively. Therefore, the first buffer 260 and the second buffer 280 can prevent damage to the front end face of the hammer housing 230 from collision with external objects (e.g., a wheel during tire changing using the impact wrench 210) when the impact wrench 210 is used. The first buffer 260 and the second buffer 280 also function to protect the lighting unit 16 from collisions.

[0113] The following is a detailed description of the structure used to mount the first buffer 260 onto the hammer housing 230. For example... Figure 30 As shown, the hammer housing 230 includes a first outer diameter portion 233, a second outer diameter portion 234, and an annular groove portion 235. The second outer diameter portion 234 is located further forward than the first outer diameter portion 233 and has an outer diameter smaller than that of the first outer diameter portion 233. The annular groove portion 235 is located between the first outer diameter portion 233 and the second outer diameter portion 234. The annular groove portion 235 includes a bottom 236 and a plurality of first protrusions 237. Figure 26 As shown, the bottom 236 has a constant outer diameter. That is, the radial position of the bottom 236 is the same in all positions along the circumference.

[0114] like Figure 26 and Figure 30 As shown, a plurality of first protrusions 237 are portions that project radially outward from the bottom 236. The plurality of first protrusions 237 extend from the first outer diameter portion 233 to the second outer diameter portion 234 in the front-rear direction. The plurality of first protrusions 237 are arranged circumferentially spaced apart. The top 237a of the first protrusions 237 is located radially inward than the outer periphery of the second outer diameter portion 234. A plurality of recesses 238 are defined between the plurality of first protrusions 237. Figure 26 As shown, the radial positions (i.e., outer diameters) of the multiple tops 237a are the same as each other.

[0115] like Figure 26 As shown, the side surfaces 237b (circumferential side surfaces) of the plurality of first protrusions 237 form an angle relative to the radial direction. Furthermore, the inclination angles of the side surfaces 237b of each of the plurality of first protrusions 237 relative to the radial direction are different. More specifically, viewed in a cross section orthogonal to the front-back direction, the uppermost first protrusion 237 has an approximately rectangular shape. The first protrusions 237 located in the region descending from the uppermost first protrusion 237 to a rotational angle position of 90 degrees have: an acute angle on the circumferentially downward side; and an obtuse angle on the circumferentially upward side. The closer to the lower first protrusion 237, the larger the angle of the acute angle (becoming increasingly obtuse). The first protrusions 237 located at the rotational angle position descending from the uppermost first protrusion 237 to a rotational angle position of 90 degrees have an approximately rectangular shape. The first protrusion 237, located in the region where it descends from the uppermost first protrusion 237 to a rotational angle of more than 90 degrees, has: an obtuse angle on the circumferentially downward side; and an acute angle on the circumferentially upward side. The closer to the lower first protrusion 237, the smaller the angle of the acute angle (becoming more acute).

[0116] like Figure 26 As shown, the circumferential widths of the multiple recesses 238 are all different. More specifically, the circumferential width of the recess 238 located at the uppermost position is the largest, and in the upper half of the region, the circumferential width of the recess 238 gradually decreases as it moves downward from the uppermost position. Moreover, in the lower half of the region, the circumferential width of the recess 238 gradually increases as it moves downward.

[0117] like Figure 18 , Figure 23 , Figure 28 and Figure 29As shown, the first buffer 260 includes an annular portion 261 and a protrusion 262. The annular portion 261 is the part that covers the hammer housing 230 about the rotation axis AX1 and has an approximately cylindrical shape. The annular portion 261 includes: a rear portion 261a, which has a constant outer diameter; and a front portion 261b, which has a tapered shape that gradually narrows towards the front. According to Figure 29 It is clearly understood that, viewed in the front-rear direction, the rear portion 261a has an approximately C-shaped opening at the lower side. The protrusion 262 protrudes radially outward from the lower edge of the annular portion 261. The protrusion 262 has a right wall portion 262a, a left wall portion 262b, and a front wall portion 262c, with openings at the lower and rear sides. The protrusion 262 has a size and shape suitable for the upper end of the support portion 53.

[0118] like Figure 28 and Figure 29 As shown, the annular portion 261 includes a first engaging portion 263. The first engaging portion 263 engages with the hammer housing 230 in a detachable manner due to its elasticity. In this embodiment, the first engaging portion 263 is a plurality of second protrusions 264. The plurality of second protrusions 264 protrude radially inward from the inner circumferential surface 261c of the rear portion 261a of the annular portion 261. The plurality of second protrusions 264 are arranged at intervals in the circumferential direction.

[0119] The plurality of second protrusions 264 have a size and shape substantially the same as the plurality of recesses 238 of the hammer housing 230, such as Figure 26 As shown, the protrusions 264 can be inserted into the plurality of recesses 238 in a suitable manner through elastic deformation. As described above, the circumferential widths of the plurality of recesses 238 are different from each other, and therefore, the circumferential widths of the plurality of second protrusions 264 are also different from each other. The rotational angular position of the first buffer 260 for inserting the plurality of second protrusions 264 into the plurality of recesses 238 is uniquely determined relative to the hammer housing 230 about the rotation axis AX1. Therefore, more precisely, the plurality of second protrusions 264 have approximately the same size and shape as the plurality of recesses 238 at the corresponding rotational angular positions.

[0120] When the first buffer 260 is installed on the hammer housing 230, as Figure 23 As shown, the first buffer 260 is positioned such that the rear edge of the annular portion 261 abuts against the front side surface 233a of the first outer diameter portion 233. Additionally, as... Figure 26As shown, a plurality of second protrusions 264 are pressed into a plurality of recesses 238. At this time, the plurality of second protrusions 264 engage with the inner surfaces of the recesses 238 in a manner that prevents them from detaching from the recesses 238. Specifically, the plurality of second protrusions 264 are received in the recesses 238 in a state of elastic deformation. The second protrusions 264 received in the recesses 238 engage with the inner surfaces of the recesses 238 using their restoring force. The plurality of second protrusions 264 can be received in the recesses 238 in a slightly compressed state and are firmly engaged with the inner surfaces of the recesses 238 using their restoring force.

[0121] The inner peripheral surface 261c of the annular portion 261 has an annular groove 265 on the front side of the plurality of second protrusions 264, adjacent to the plurality of second protrusions 264. For example... Figure 23 As shown, the annular groove 265 has a size and shape suitable for the second outer diameter portion 234 of the hammer housing 230. In the installed state of the first buffer 260, the second outer diameter portion 234 of the hammer housing 230 is engaged with the annular groove 265.

[0122] like Figure 29 As shown, the protrusion 262 includes a second engaging portion 266. The second engaging portion 266, due to its elasticity, engages detachably with the housing 250 (more specifically, the upper end 53a of the support portion 53). In this embodiment, the second engaging portion 266 is a pair of protrusions 267 facing each other in the left-right direction. One protrusion 267 protrudes from the inner surface of the left wall portion 262b toward the right, and the other protrusion 267 protrudes from the inner surface of the right wall portion 262a toward the left.

[0123] like Figure 29 As shown, the protrusion 267 has a shaft portion 268 and a head portion 269. The shaft portion 268 is a cylindrical portion extending from the left wall portion 262b or the right wall portion 262a in a left-right direction. The head portion 269 is located at the end of the shaft portion 268 and has an outer diameter larger than that of the shaft portion 268.

[0124] like Figure 24 , 25 As shown, in the upper end portion 53a of the support portion 53, a threaded boss 56a is provided in the portion corresponding to the first portion 250a. This threaded boss 56a is shown as threaded boss 356a in the accompanying drawings. Figure 27As shown, the threaded boss 356a has a small-diameter bore portion 351 and a large-diameter bore portion 352. The small-diameter bore portion 351 is the outer (right) portion of the threaded boss 356a. The large-diameter bore portion 352 is continuous with the small-diameter bore portion 351 on the inner (left) side of the upper end portion 53a. The large-diameter bore portion 352 has an inner diameter larger than that of the small-diameter bore portion 351. The shaft portion 268 has an outer diameter smaller than that of the small-diameter bore portion 351. The head 269 has an outer diameter larger than that of the small-diameter bore portion 351 and smaller than that of the large-diameter bore portion 352.

[0125] like Figure 27 As shown, when the first buffer 260 is installed on the upper end 53a of the support portion 53, the protrusion 267 on the right side of the first buffer 260 is inserted into the threaded boss 356a. The outer diameter of the head 269 of the protrusion 267 is larger than the inner diameter of the small-diameter hole 351, but the head 269 can be inserted into the large-diameter hole 352 by elastically deforming and pressing it in. At this time, the protrusion 267 engages with the inner surface of the threaded boss 356a in a manner that will not fall off. The plurality of second protrusions 264 engage with the inner surface of the plurality of recesses 238 in a manner that will not fall off. Specifically, a stepped portion 353 is defined between the small-diameter hole 351 and the large-diameter hole 352 due to the difference in the inner diameters of the small-diameter hole 351 and the large-diameter hole 352. The head 269 of the protrusion 267, which is inserted into the large-diameter hole 352, engages with the stepped portion 353, thereby holding the right-side protrusion 267 within the threaded boss 356a. Thus, the right wall portion 262a of the first buffer 260 is mounted to the support portion 53.

[0126] like Figure 27 As shown, in the upper end portion 53a of the support portion 53, a portion corresponding to the second portion 250b has a hole 355. The hole 355 is positioned in the same vertical and horizontal directions as the threaded boss 356a. The hole 355 includes a small-diameter hole 356 and a large-diameter hole 357. The small-diameter hole 356 has the same inner diameter as the small-diameter hole 351, and the large-diameter hole 357 has the same inner diameter as the large-diameter hole 352. When the first buffer 260 is installed on the upper end portion 53a of the support portion 53, the protrusion 267 on the left side of the first buffer 260 is inserted into the hole 355. Thus, similar to when the right protrusion 267 is inserted into the threaded boss 356a, the left protrusion 267 is held in a engaged state within the hole 355. Therefore, the left wall portion 262b of the first buffer 260 is installed on the support portion 53.

[0127] In conventional impact wrenches, where a resin housing is positioned below a metal housing, the protective cover cannot engage with the metal housing at the location of the resin housing. In this case, the protective cover can easily detach accidentally from the metal housing. This problem is not limited to electric impact wrenches; it is common to various power tools with metal housings, such as impact screwdrivers and shearing wrenches.

[0128] On the other hand, according to the aforementioned impact wrench 210, such as Figure 24 and Figure 25 As indicated by arrow AR1, the first buffer 260 is inserted into the front portion of the hammer housing 230 from the front side, such that the first engaging portion 263 of the first buffer 260 engages with the recess 238 of the hammer housing 230, and the second engaging portion 266 of the first buffer 260 engages with the threaded boss 356a and the hole 355 of the support portion 53, respectively. This allows the first buffer 260 to be installed. In other words, the first buffer 260 is installed by engaging the first engaging portion 263 with the hammer housing 230 and engaging the second engaging portion 266 with the support portion 53 adjacent to the hammer housing 230 in the vertical direction. Therefore, compared to a structure where the first buffer 260 only engages with the hammer housing 230, accidental detachment of the first buffer 260 can be prevented. Furthermore, if the first buffer 260 is stretched forcefully in the direction of disengagement, causing elastic deformation, the first buffer 260 can be removed.

[0129] Furthermore, the first buffer 260 can be easily assembled and disassembled by pressing the pair of protrusions 267 of the second engaging portion 266 of the first buffer 260 into the threaded boss 356a and the hole 355 of the support portion 53, respectively, and by pulling them out in the opposite direction. In addition, the stepped portion of the threaded boss 356a and the hole 355 engages with the head 269 of the protrusion 267, thus establishing a secure engagement relationship.

[0130] Furthermore, according to the impact wrench 210, the threaded boss 356a of the first part 250a, which is used to join the first part 250a and the second part 250b of the housing 250, can also be used as a hole for engaging the support part 53 and the first buffer 260 (protrusion 262). Therefore, compared to the case where a hole 355 or similar hole for the second part 250b is provided separately in addition to the threaded boss 356a for such engagement, the structure of the housing 250 (first part 250a) can be simplified.

[0131] Furthermore, according to the impact wrench 210, the second outer diameter portion 234 of the hammer housing 230 has an outer diameter smaller than that of the first outer diameter portion 233 (see reference). Figure 30Therefore, the first buffer 260 is installed in the hammer housing 230 by inserting the plurality of second protrusions 264 of the first buffer 260 into the plurality of recesses 238 of the hammer housing 230 (see reference). Figure 26 Below, such as Figure 23 As shown, in the position where the second protrusion 264 is absent in the circumferential direction, the annular portion 261 of the first buffer 260 is also deeply embedded in the annular groove 235 between the first outer diameter portion 233 and the second outer diameter portion 234, and is clamped in the front-to-back direction by the front side surface 233a of the first outer diameter portion 233 and the rear side surface 234a of the second outer diameter portion 234. Therefore, the locking force is increased, which can further suppress the accidental peeling of the first buffer 260.

[0132] Hereinafter, regarding the impact wrench 410 according to the fourth embodiment, refer to Figures 31-33 Only the differences relative to the third embodiment will be described. For example... Figure 31 As shown, the right surface of the upper end portion 53a of the support portion 53 of the impact wrench 410 has two holes 455 on the upper side of the threaded boss 56a, which is located at a position corresponding to the threaded boss 356a in the third embodiment. Although the figure is omitted, the left surface of the upper end portion 53a also has two holes 455 at the same positions in the vertical and horizontal directions as the right surface.

[0133] like Figure 33 As shown, in the fourth embodiment, the protrusion 262 of the first buffer 460 replaces the second engaging portion 266 of the third embodiment, thus providing a second engaging portion 466. The second engaging portion 466 utilizes its elasticity to engage detachably with the housing 250 (more specifically, the upper end portion 53a of the support portion 53). The second engaging portion 466 includes two protrusions 467 protruding from the inner surface of the left wall portion 262b toward the right; and two protrusions 467 protruding from the inner surface of the right wall portion 262a toward the left. Similar to the shaft portion 268 and head 269 of the protrusion 267 in the third embodiment, the protrusion 467 also includes a shaft portion 468 and a head 469.

[0134] like Figure 32 As shown, similar to the small-diameter hole portion 356 and the large-diameter hole portion 357 in the third embodiment, the hole portion 455 is provided with both a small-diameter hole portion 456 and a large-diameter hole portion 457. Furthermore, the head 469 of the protrusion 467 inserted into the large-diameter hole portion 457 engages with the step portion 458 between the small-diameter hole portion 456 and the large-diameter hole portion 457. According to this fourth embodiment, the same effects as in the third embodiment can also be obtained.

[0135] The third and fourth embodiments described above are provided for easy understanding of the present invention and are not intended to limit the invention. The present invention can be modified and improved without departing from its spirit, and its equivalents are included. Furthermore, within the scope of solving at least a portion of the above-mentioned problems or achieving at least a portion of the effects, the structural elements described in the claims and specification can be arbitrarily combined or omitted.

[0136] For example, as long as the engagement utilizing the elasticity of the first engagement portion 263 is provided, the engagement structure of the hammer housing 230 and the first buffer 260 can be changed to any other structure. Similarly, as long as the engagement utilizing the elasticity of the second engagement portion 266 is provided, the engagement structure of the support portion 53 and the second engagement portion 266 of the first buffer 260 can be changed to any other structure. For example, the engagement structure of the support portion 53 and the second engagement portion 266 can be changed to a structure in which the support portion 53 has a protrusion and the second engagement portion 266 has a hole for inserting the protrusion.

[0137] Furthermore, the resin housing 250 can be changed to any shape. In this case, the second engaging portion 266 of the first buffer 260 can replace the support portion 53 and engage with the housing 250 at any part of the portion of the housing 250 adjacent to the hammer housing 230 in the vertical direction, depending on the shape of the resin housing 250.

[0138] The above-described embodiments are not limited to impact wrenches, but can be applied to various power tools with metal housings (such as impact screwdrivers, shearing wrenches, etc.).

[0139] The present invention can also be implemented in the following ways.

[0140] [Method 1]

[0141] A power tool, wherein,

[0142] The power tool includes:

[0143] motor;

[0144] The final output shaft is capable of rotating about the axis of rotation.

[0145] A power transmission mechanism is connected to the motor in an actuating manner and configured to transmit the rotational driving force of the motor to the final output shaft;

[0146] A metal housing having a cylindrical shape extending along an axial direction that is the direction in which the rotation axis extends, the final output shaft being partially housed in the metal housing, and the metal housing housing at least a portion of the power transmission mechanism;

[0147] A protective cover, which is elastic, covers the front portion of the metal housing about the axis of rotation when the axial direction is defined as the front-rear direction, the side where the final output shaft is located in the front-rear direction is defined as the front side, and the opposite side of the final output shaft is defined as the rear side, and is installed in a manner detachable from the front of the metal housing; and

[0148] A resin outer shell is adjacent to the metal outer shell in a direction orthogonal to the axial direction.

[0149] The protective cover has the following features:

[0150] An annular portion having a first engaging portion configured to detachably engage with the metal housing using the elasticity of the protective cover, and covering the metal housing about the axis of rotation; and

[0151] The protrusion has a second engaging portion configured to engage with the resin outer shell in a detachable manner using the elasticity of the protective cover, and protrudes radially outward from the annular portion.

[0152] [Method 2]

[0153] According to the power tool of method 1, wherein,

[0154] The resin outer shell has holes.

[0155] The second engaging portion has a protrusion that is inserted into the hole and engages with the inner surface of the resin shell that defines the hole.

[0156] [Method 3]

[0157] According to the power tool of method 2, wherein,

[0158] The aperture includes: a small-diameter aperture having a first inner diameter; and a large-diameter aperture having a second inner diameter greater than the first inner diameter, and being continuous relative to the small-diameter aperture at a position closer to the inside of the resin shell than the small-diameter aperture.

[0159] The protrusion comprises: a shaft portion having an outer diameter smaller than the first inner diameter; and a head portion having an outer diameter larger than the first inner diameter and smaller than the second inner diameter, located at the end of the shaft portion.

[0160] The protrusion engages with the step portion between the small-diameter hole and the large-diameter hole in a manner that prevents it from falling out of the hole.

[0161] [Technical Solution 4]

[0162] According to the power tools of method 3, wherein...

[0163] The resin outer shell has a split structure that allows it to be separated into a first part and a second part.

[0164] The hole includes a threaded boss for inserting a screw to join the first portion and the second portion.

[0165] [Method 5]

[0166] According to any one of methods 1 to 4, the power tool, wherein

[0167] The metal housing includes: a first outer diameter portion having a first outer diameter; a second outer diameter portion located further forward than the first outer diameter portion and having a second outer diameter smaller than the first outer diameter; and an annular groove located between the first outer diameter portion and the second outer diameter portion.

[0168] The annular groove includes: a bottom; and a plurality of first protrusions that project radially outward from the bottom and are arranged at circumferential intervals.

[0169] The tops of the plurality of first protrusions are located radially further inward than the outer periphery of the second outer diameter portion.

[0170] The first engaging portion has a plurality of second protrusions arranged at circumferential intervals. These protrusions are elastically deformed and appropriately inserted into a plurality of recesses defined between the plurality of first protrusions, engaging with the inner surfaces of the recesses in a manner that prevents them from falling out.

[0171] The annular portion is clamped in the front-back direction by the first outer diameter portion and the second outer diameter portion when the plurality of second protrusions are respectively inserted into the plurality of recesses.

[0172] [Technical Solution 6]

[0173] According to any one of methods 1 to 5, of the power tools,

[0174] The resin outer shell comprises:

[0175] A battery holding section is configured to hold a removable battery that serves as the power source for the motor.

[0176] A handle, located between the battery holder and the metal housing in a direction orthogonal to the axial direction, and extending in an elongated shape in a direction substantially orthogonal to the axial direction; and

[0177] The support column, located further forward than the handle, extends in a long strip, generally parallel to the handle, between the battery holder and the metal housing.

[0178] The second engaging portion engages with the support portion.

Claims

1. An electric tool, wherein, The power tool includes: motor; The final output shaft is capable of rotation; A power transmission mechanism is connected to the motor in an actuating manner and configured to transmit the rotational driving force of the motor to the final output shaft; A resin housing having a motor housing, a battery holder, and a handle, wherein when the axial direction of the final output shaft is defined as the front-rear direction, and the side in the front-rear direction where the final output shaft is located is defined as the front side and the opposite side of the final output shaft is defined as the rear side, the motor housing has a cylindrical shape extending along the front-rear direction and housing the motor, the battery holder holds a removable battery that serves as the power source for the motor, and the handle extends in a long strip between the motor housing and the battery holder in a direction substantially orthogonal to the front-rear direction; as well as A metal housing, located at the front of the motor housing, has a cylindrical portion and a protrusion. The cylindrical portion has a cylindrical shape extending in the front-rear direction and communicating with the interior of the motor housing. The final output shaft is partially housed in the cylindrical portion, and the cylindrical portion houses at least a portion of the power transmission mechanism and is connected to the motor housing by a threaded connection. The protrusion protrudes radially outward from the cylindrical portion. When the direction orthogonal to the front-back direction and approximately parallel to the length direction of the handle portion is defined as the up-down direction, and the side where the motor housing portion is located in the up-down direction is defined as the upper side and the side where the battery holding portion is located is defined as the lower side, the protrusion has a second engaging portion. This second engaging portion engages with the first engaging portion of the resin housing at a position further forward than the connection position between the motor housing portion and the cylindrical portion, and is located at a position further downward than the first engaging portion.

2. The power tool according to claim 1, wherein, The protrusion includes: a base that protrudes downward from the lowest part of the cylindrical portion; and a cross-direction extension that extends from the base in a direction intersecting the vertical direction and has the second engaging portion.

3. The power tool according to claim 2, wherein, The intersecting extension extends in a direction orthogonal to the vertical direction. At least a portion of the upper surface of the cross-direction extension functions as the second engaging portion.

4. The power tool according to claim 3, wherein, When the direction orthogonal to the front-back direction and the up-down direction is defined as the left-right direction, the cross-direction extension extends from the base toward the right and left sides.

5. The power tool according to claim 3 or claim 4, wherein, The resin outer shell has a recess that is adapted to the size and shape of the intersecting direction extension and accommodates the intersecting direction extension. On the inner surface of the resin housing that defines the recess, at least a portion of the downward-facing side functions as the first engaging portion.

6. The power tool according to any one of claims 1 to 5, wherein, The first engaging portion and the second engaging portion engage through surface contact.

7. The power tool according to any one of claims 1 to 6, wherein, The second engaging portion is positioned in the front-rear direction corresponding to the front half of the metal housing.

8. The power tool according to claim 7, wherein, The resin housing also includes a support column located further forward than the handle portion, extending in an elongated shape between the battery holder and the metal housing, generally parallel to the handle portion. The first engaging portion is located at the end of the support portion on the side opposite to the battery holding portion.

9. The power tool according to any one of claims 1 to 8, wherein, The first engaging portion includes: a front engaging portion; and a rear engaging portion, which is separated from the front engaging portion in the front-rear direction and is located further rearward than the front engaging portion. The second engaging portion includes: a front second engaging portion that engages with a front first engaging portion; and a rear second engaging portion that is separated from the front second engaging portion in the front-rear direction, is located at a position further rearward than the front second engaging portion, and engages with the rear first engaging portion.

10. The power tool according to any one of claims 2 to 5 and claims 6 to 9 which are dependent on claim 2, wherein, The first engaging portion includes: an upper first engaging portion; and a lower first engaging portion, which is separated from the upper first engaging portion in the vertical direction and is located at a lower position than the upper first engaging portion. The cross-direction extension includes: an upper second engaging portion that engages with the upper first engaging portion; and a lower second engaging portion that is separated from the upper second engaging portion in the vertical direction, is located at a position lower than the upper second engaging portion, and engages with the lower first engaging portion.

11. The power tool according to any one of claims 1 to 10, wherein, The resin outer shell has a bi-half-part structure that can be separated into a right side portion and a left side portion in a direction orthogonal to the front-back direction and the up-down direction. The power tool includes a plurality of screws that join the right side portion and the left side portion. The plurality of screws do not penetrate the protrusion but instead join the right side portion and the left side portion.

12. The power tool according to any one of claims 1 to 10, wherein, The resin outer shell has a bi-half-part structure that can be separated into a right side portion and a left side portion in a direction orthogonal to the front-back direction and the up-down direction. The power tool includes a plurality of screws that join the right side portion and the left side portion. At least one of the plurality of screws engages the right side portion and the left side portion while the protrusion is penetrated.

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