Rotary impact tool

Abstract

A power tool includes a housing, a motor mounted within the housing and including a stator having an outer diameter and a rotor having a shaft configured to rotate relative to the stator about an axis. The power tool also includes a gear assembly operably coupled to the motor and including a ring gear fixed relative to the housing and a planetary gear engaged with the ring gear. The drive assembly is operably coupled to the gear assembly to receive torque from the shaft through the gear assembly. The power tool also includes a rear bearing rotatably supporting a rear portion of the shaft and a front bearing rotatably supporting a front portion of the shaft. A distance measured between a front edge of the rear bearing and a rear edge of the front bearing is less than an outer diameter of the stator.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 284,887 filed on December 1, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The utility model relates to a power tool, and more particularly to a rotary impact tool, such as an impact wrench. Background Art

[0004] Rotary impact tools are typically used to provide an impact rotational force to a tool element or workpiece (eg, a fastener) or to intermittently apply torque to tighten or loosen the fastener. Utility Model Content

[0005] In one aspect, the utility model provides a power tool, which includes a housing, a motor installed in the housing, the motor including a stator defining an outer diameter and having a plurality of windings, and a rotor having a shaft, the shaft being configured to rotate relative to the stator around an axis. The power tool also includes a gear assembly operably connected to the motor, the gear assembly including a ring gear fixed relative to the housing and a plurality of planetary gears meshing with the ring gear. The drive assembly is operably connected to the gear assembly to receive torque from the shaft through the gear assembly, and includes a camshaft, an anvil, and a hammer configured to reciprocate along the camshaft to apply a rotary impact to the anvil in response to the rotation of the camshaft. The power tool also includes a rear bearing rotatably supporting the rear portion of the shaft and a front bearing rotatably supporting the front portion of the shaft. The distance measured between the front edge of the rear bearing and the rear edge of the front bearing is less than the outer diameter of the stator.

[0006] Optionally, the housing includes a first portion and a second portion coupled together at a seam, and an end cap coupled to the first portion and the second portion.

[0007] Optionally, the first portion and the second portion define a portion of the motor housing directly supporting the stator.

[0008] Optionally, the power tool includes an impact box coupled to the housing, and the impact box encloses the drive assembly.

[0009] Optionally, the power tool includes an intermediate housing disposed between the motor housing portion and the impact box, and the ring gear, the impact box and the intermediate housing at least partially define a sealed chamber containing the gear assembly and the drive assembly.

[0010] Optionally, the rear bearing is supported by an end cap.

[0011] Optionally, the ring gear includes a boss extending rearwardly along the axis, and the front bearing is received in and supported by the boss.

[0012] Alternatively, the ring gear includes a toothed portion and a flange portion extending from the toothed portion, and the flange portion rotatably supports the cam shaft.

[0013] Optionally, the outer diameter of the stator is 50 mm to 70 mm.

[0014] Optionally, the power tool includes a battery removably coupled to the housing and configured to provide power to the motor.

[0015] The utility model provides a power tool in another aspect, the power tool comprising: a housing having a first housing portion and a second housing portion connected to the first housing portion, the first housing portion and the second housing portion contacting each other at a joint; a motor directly mounted in the housing between the first housing portion and the second housing portion; a gear box formed integrally by the first housing portion and the second housing portion; a gear assembly supported in the gear box and operably connected to the motor; and a drive assembly operably connected to the gear assembly. The drive assembly comprises a camshaft, an anvil and a hammer, the hammer being configured to reciprocate along the camshaft to apply a rotary impact to the anvil in response to the rotation of the camshaft. The power tool further comprises an impact box coupled to the housing. The impact box surrounds the hammer and the anvil. The impact box has a first end facing the housing and a second end opposite to the first end, and the anvil extends through the second end of the impact box. The impact box and the gear box define a chamber containing a lubricant, and the power tool comprises a sealing system at least partially positioned between the gear box and the impact box to inhibit the lubricant from escaping from the chamber.

[0016] Optionally, the first housing portion and the second housing portion define a slot, and the ring gear is supported within the slot.

[0017] Optionally, the housing includes a dividing wall extending between the motor and the gear assembly, the shaft of the motor extends through an opening in the dividing wall, and the ring gear seats on the dividing wall.

[0018] Optionally, the ring gear includes a boss extending rearwardly along the axis, and the shaft of the motor is supported by a bearing received in the boss.

[0019] Optionally, the housing and the impingement box are coupled together by one or more fasteners each received in an insert secured within the housing and formed of a metallic material.

[0020] The utility model provides a power tool on the other hand, which includes: a housing, the housing having a first housing part and a second housing part, the first housing part and the second housing part are both made of polymer material, and the first housing part and the second housing part are connected together at a joint; a motor, the motor is installed in the housing, between the first housing part and the second housing part, and the motor includes a shaft configured to rotate around an axis; a gear box, the gear box contains lubricant and is integrally formed by the first housing part and the second housing part; and a gear assembly, the gear assembly is supported in the gear box and operably connected to the motor. The gear assembly includes a ring gear engaged with the gear box and a plurality of planetary gears meshing with the ring gear. The power tool also includes a drive assembly operably connected to the gear assembly. The drive assembly includes a camshaft, an anvil and a hammer, the hammer is configured to reciprocate along the camshaft to apply a rotary impact to the anvil in response to the rotation of the camshaft. An impact box made of a metal material is connected to the housing and surrounds the drive assembly. The impact box contains lubricant. The power tool further includes a seal that prevents the lubricant from migrating out of the gear box and the impact box.

[0021] Optionally, the sealing system further comprises at least a first portion, a second portion and a third portion, and the first portion, the second portion and the third portion seal the chamber.

[0022] Optionally, the first part of the sealing system is at least partially positioned between the first housing portion and the second housing portion, on the upper portion and the lower portion of the chamber.

[0023] Optionally, the gear assembly further comprises a plurality of planet gears, and a ring gear surrounding the plurality of planet gears, and the first portion surrounds the ring gear.

[0024] Optionally, a groove is formed between the first housing portion and the second housing portion, and the first part of the sealing system is received in the groove.

[0025] Optionally, a portion of the groove comprises an L-shape, and the first portion is received around the ring gear and in the groove.

[0026] Optionally, the first part of the sealing system comprises two mirror-image parts located opposite each other.

[0027] Optionally, a second portion of the sealing system is positioned adjacent the first end of the impact box and a third portion of the sealing system is positioned adjacent the second end of the impact box, the second portion of the sealing system is retained between the impact box and the housing, and the third portion of the sealing system is retained by a seal retainer surrounding the anvil.

[0028] Optionally, the housing includes a front end portion, and the impingement box includes a rim received within and overlapping the front end portion, and the second part of the sealing system includes an O-ring sandwiched between the front end portion of the housing and the rim.

[0029] Optionally, the first part, the second part and the third part of the sealing system are formed as separate pieces, the first part is located between the gear assembly and the housing to seal the rear end of the chamber, the second part is located between the impact box and the housing to seal the middle part of the chamber, the third part of the sealing system is located between the drive assembly and the impact box to seal the front part of the chamber, and the first part of the sealing system extends between the rear end of the chamber to the middle part of the chamber.

[0030] The utility model provides a power tool in another aspect, the power tool comprising: a housing, the housing comprising a first housing part and a second housing part, the first housing part and the second housing part are both made of a polymer material, the first housing part and the second housing part are connected together at a joint; a motor, the motor is installed in the housing, between the first housing part and the second housing part, the motor comprises a shaft configured to rotate around an axis; a gear box, the gear box contains a lubricant and is integrally formed by the first housing part and the second housing part; a gear assembly, the gear assembly is supported in the gear box and operably connected to the motor, the gear assembly comprises a ring gear engaged with the gear box, and a plurality of planetary gears meshing with the ring gear; and a drive assembly, the drive assembly is operably connected to the gear assembly. The drive assembly comprises a camshaft, an anvil and a hammer, the hammer is configured to reciprocate along the camshaft to apply a rotary impact to the anvil in response to the rotation of the camshaft. The power tool further includes an impact box made of a metal material and coupled to the housing, the impact box surrounding the drive assembly and containing lubricant, and a seal that inhibits the lubricant from migrating out of the gear box and the impact box.

[0031] Optionally, the first housing portion and the second housing portion define a slot, and wherein the ring gear is supported within the slot.

[0032] Optionally, the housing includes a dividing wall extending between the motor and the gear assembly, wherein a shaft of the motor extends through an opening in the dividing wall, and wherein the ring gear sits on the dividing wall.

[0033] Optionally, the ring gear includes a boss extending rearwardly along the axis, and wherein the shaft of the motor is supported by a bearing received in the boss.

[0034] Optionally, the housing and the impingement box are coupled together by one or more fasteners each received in an insert secured within the housing and formed of a metallic material.

[0035] The utility model provides a power tool in another aspect, which includes: a housing having a first housing portion and a second housing portion connected together at a joint; a motor mounted in the housing and including an output shaft capable of rotating about an axis; an impact box connected to the housing; an impact mechanism, which is at least partially supported in the impact box, and the impact mechanism includes a camshaft, an anvil and a hammer, the hammer being configured to reciprocate along the camshaft to apply a rotary impact to the anvil in response to the rotation of the camshaft; and a gear assembly, which is supported in the housing and operably connected to the output shaft. The gear assembly includes a plurality of planetary gears surrounding a portion of the output shaft and a ring gear surrounding the plurality of planetary gears. The power tool also includes a bushing supported by the housing between the camshaft and the gear set. The plurality of planetary gears are connected to the camshaft by one or more pins so that the plurality of planetary gears are cantilevered and supported on the camshaft.

[0036] Optionally, each of the first housing portion and the second housing portion forms a first groove configured to directly receive the gear assembly and a second groove configured to directly receive the bushing, wherein the first groove and the second groove are offset relative to each other along the axis.

[0037] Optionally, the first groove receives the ring gear, and the ring gear includes one or more lugs that contact the housing to inhibit rotational movement of the ring gear relative to the housing.

[0038] Optionally, the second groove receives the bushing, and the bushing includes one or more lugs that contact the housing to inhibit rotational movement of the bushing relative to the housing.

[0039] Optionally, the bushing comprises at least four lugs.

[0040] Optionally, a bushing at least partially supports the camshaft in the housing, and one or more pins pass through apertures in the bushing between the planetary gears and the camshaft.

[0041] On the other hand, the utility model provides a power tool, which includes a housing having a motor housing portion and a handle housing portion extending from the motor housing portion. The housing is made of a molded polymer material. The power tool further includes: a motor supported in the motor housing portion; a trigger supported by the handle housing portion, the trigger being configured to operate the motor; a battery socket configured to receive a battery pack that can be removably connected to the power tool, the battery socket including one or more support rails molded therein; a PCBA positioned in the handle housing portion and electrically connected to the motor assembly, the trigger and the battery socket; and a frame molded in the handle housing portion and at least partially surrounding the PCBA, the frame being configured to strengthen the handle housing. The frame is made of a different material from the housing.

[0042] Optionally, the power tool comprises a grip overmolded onto the handle housing portion, the grip being configured for gripping by a user during operation of the power tool.

[0043] Optionally, the frame comprises a plurality of frame members formed within the handle housing portion.

[0044] Optionally, a plurality of frame members extend between the battery receptacle and the trigger.

[0045] Optionally, a plurality of frame members extend from the battery receptacle and extend beyond the trigger.

[0046] Optionally, each of the frame members is made of metal.

[0047] Optionally, each of the frame members comprises a plurality of apertures.

[0048] Optionally, one of the plurality of frame members includes a slot for receiving an electronic component mounted to the PCBA.

[0049] Optionally, the frame is a first frame, the power tool further comprises a second frame molded in the battery socket, and the second frame is made of a different material from the housing.

[0050] Optionally, the second frame is made of metal.

[0051] Optionally, the second frame reinforces the track of the battery socket.

[0052] Optionally, the first frame and the second frame comprise metal stampings.

[0053] Optionally, the battery receptacle includes an elastomeric element engageable with the battery pack when the battery pack is coupled to the power tool.

[0054] Optionally, the elastomeric element is one of a plurality of elastomeric elements positioned in the battery receptacle and engageable with the battery pack.

[0055] By considering the detailed description and the accompanying drawings, other features and aspects of the utility model will become clear. Any feature (one or more) described herein for one aspect or embodiment can be combined with any other feature (one or more) described herein for any other aspect or embodiment when appropriate and applicable. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 It is a stereoscopic view of a power tool according to an embodiment of the utility model.

[0057] Figure 2A is along Figure 1 The line 2A-2A is intercepted Figure 1 A cross-sectional view of a power tool is shown with a battery pack of the power tool removed and illustrating callouts surrounding a portion of a sealing system of the power tool.

[0058] Figure 2B When positioned at Figure 2A The area shown in the callout is an enlarged view of a portion of an alternative sealing system that may be used with the power tool.

[0059] Figure 2C yes Figure 1 A cross-sectional view of a portion of a power tool.

[0060] Figure 3 yes Figure 1 A quarter cutaway view of a power tool.

[0061] Figure 4 yes Figure 1 A three-dimensional view of the handle portion of a power tool, in which the first housing portion is hidden.

[0062] Figure 5 It is along Figure 1 The line 5-5 is intercepted Figure 1 A cross-sectional view of a handle portion of a power tool.

[0063] Figure 6 yes Figure 4 A partially exploded bottom perspective view of the handle portion of the .

[0064] Figure 7 is along Figure 4 A cross-sectional view taken along line 7-7 with the battery pack removed.

[0065] Figure 8 yes Figure 1 A partially exploded view of a power tool.

[0066] Fig. 9 yes Figure 1 A side view of a power tool with the first housing portion hidden to show the motor, gears and drive assembly.

[0067] Fig.10 yes Figure 1 A side perspective view of a power tool in which a first housing portion and a portion of the gear assembly are hidden.

[0068] Fig.11 yes Figure 1 Power tools along Figure 1 A cross-sectional view taken along line 11-11.

[0069] Fig.12 is an isolated view of the sealing system of FIG. 2 .

[0070] Fig.13 According to another embodiment, Figure 1 A perspective view of a sealing system for use with a power tool.

[0071] Fig.14 yes Fig.13 Magnified view of the sealing connection of the sealing system.

[0072] Fig.15 and Fig.16 yes Figure 1 Dimensioned views of a power tool illustrating certain dimensions associated with the power tool in some embodiments.

[0073] Fig.17A is a cross-sectional view of a power tool according to another embodiment of the utility model.

[0074] Fig. 17B is Fig.17A An enlarged view of a portion of the sealing system in the area of ​​the callout is shown.

[0075] Before explaining any embodiment of the utility model in detail, it should be understood that the application of the utility model is not limited to the details of the component construction and arrangement set forth in the following description or shown in the following drawings. The utility model can have other embodiments and can be practiced or executed in various ways. In addition, it should be understood that the words and terms used herein are for descriptive purposes and should not be regarded as limiting. DETAILED DESCRIPTION

[0076] Figure 1An embodiment of a power tool is shown in the form of a rotary impact tool, and more particularly in the form of an impact wrench 10. The impact wrench 10 includes a housing 14 having a motor housing portion 18, an impact box or front housing portion 22 coupled to the motor housing portion 18 (e.g., by a plurality of fasteners 24), and a handle portion 26 extending downwardly from the motor housing portion 18. In the illustrated embodiment, the handle portion 26 and the motor housing portion 18 are defined by cooperating first and second clamshell halves or first and second housing portions 28a, 28b.

[0077] The illustrated housing 14 also includes an end cap 30 coupled to the motor housing portion 18 opposite the front housing portion 22. The clamshell halves 28a, 28b may be coupled (e.g., fastened) together at an interface or seam 31. In the illustrated embodiment, the end cap 30 is continuous and may be pressed or fitted onto the rear ends of the clamshell halves 28a, 28b. In other words, the end cap 30 may not include two halves such that the end cap 30 may extend over the seam 31. The end cap 30 is secured to the motor housing portion 18 by a plurality of fasteners 120 ( Figure 3 and Fig.11 ) is coupled to the motor housing portion 18. In other embodiments, the end cap 30 can be formed integrally with the motor housing portion 18.

[0078] The impact wrench 10 further includes a lighting assembly 32 having one or more lighting sources 33. The illustrated lighting assembly 32 surrounds the front housing portion 22 and may serve as a cover at the front end of the front housing portion 22. In some embodiments, the lighting assembly 32 may include one or more lenses covering the one or more lighting sources 33. In some embodiments, the one or more lighting sources 33 may be light emitting diodes (LEDs) arranged around a center point of the lighting assembly 32.

[0079] Reference Figure 1 The impact wrench 10 includes a battery 34 that is removably coupled to a battery receptacle 38 located at the bottom end or foot 40 of the handle portion 26. When the battery 34 is coupled to the battery receptacle 38, the motor 42 ( Figure 2A ) is supported within the motor housing portion 18 and receives power from the battery 34 via connectors, pads, and / or battery terminals 43 supported by the battery receptacle 38. Figure 1 As shown in FIG. 4 , the foot 40 may include one or more vents 44 (eg, air vents, cooling vents, etc.). In the illustrated embodiment, the handle portion 26 of the clamshell halves 28 a , 28 b may be covered or surrounded by a grip portion 45 .

[0080] The battery 34 may be a power tool battery pack commonly used to power power tools such as electric drills, electric saws, etc. (e.g., an 18-volt rechargeable battery pack, or an M18 REDLITHIUM battery pack sold by Milwaukee Electric Tool Corporation). The battery 34 may include lithium-ion (Li-ion) battery cells. In alternative embodiments, the battery pack may have a different chemical composition (e.g., nickel-cadmium (NiCa or NiCad), nickel-hydride, etc.). In the illustrated embodiment, the battery 34 is an 18-volt battery pack. In alternative embodiments, the capacity of the battery 34 may vary (e.g., the battery may be a 4-volt battery pack, a 28-volt battery pack, a 40-volt battery pack, or any other voltage battery pack suitable for providing power to the impact wrench 10).

[0081] refer to Figure 2A and Figure 3 In the illustrated embodiment, the motor 42 is a brushless direct current ("BLDC") motor having a stator 46 and a rotor, and an output shaft 50 is rotatable about an axis 54 relative to the stator 46. In other embodiments, other types of motors may be used. A fan 58 is coupled to the output shaft 50 behind the motor 42 to generate air flow. In the illustrated embodiment, the motor 42 is operable (e.g., controlled) without the use of a Hall effect sensor. Thus, a printed circuit board adjacent to the front or rear end of the motor 42 is not required, thereby allowing a shorter length required to accommodate the motor 42 in the housing 14.

[0082] The impact wrench 10 also includes a switch 62 (e.g., a trigger switch; FIG. 2 ) supported by the housing 14 that selectively electrically connects the motor 42 (e.g., via suitable control circuitry disposed on one or more printed circuit board assemblies (“PCBAs”) 63 a, 63 b) to the battery 34 to provide DC power to the motor 42. In other embodiments, the impact wrench 10 may include a power cord for electrically connecting the switch 62 and the motor 42 to an AC power source. As another alternative, the impact wrench 10 may be configured to operate using a different power source (e.g., a pneumatic or hydraulic power source, etc.).

[0083] Now refer to Figure 4, the first PCBA 63a is positioned within the handle portion 26 and is in electrical communication with the motor 42, the switch 62, and the battery receptacle 38. In the illustrated embodiment, the first PCBA 63a includes a plurality of semiconductor switching elements (e.g., MOSFETs, IGBTs, etc.) that control and distribute power to the windings in the stator 46 to rotate the rotor and the output shaft 50. The first PCBA 63a may also include one or more microprocessors, machine-readable non-transitory memory elements, and other electrical or electronic components for providing operational control to the impact wrench 10.

[0084] Continue to refer Figure 4 , the impact wrench 10 shown includes a second PCBA 63b located in the foot 40 of the impact wrench 10. The second PCBA 63b includes one or more indicators 60 configured to indicate an operating state or mode of the impact wrench 10. The second PCBA 63b may also include one or more communication modules (e.g., Bluetooth, Wi-Fi, etc.) for linking with an external device to control the operating state or mode of the impact wrench 10.

[0085] refer to Figure 4 and Figure 5 , a frame 64 (e.g., one or more stampings, shields, plates, and / or the like) is embedded within the handle portion 26 and at least partially surrounds the first PCBA 63a. In the illustrated embodiment, the frame 64 includes a plurality of frame members located within the handle portion 26 adjacent to the grip portion 45. For example, each of the clamshell halves 28a, 28b can include embedded frame members to collectively define the frame 64. In the illustrated embodiment, the frame members are formed as stamped plates with curved regions that generally match the curvature of the grip portion 45.

[0086] The frame 64 strengthens the handle portion 26 to resist, for example, flexing, cracking, bending, and / or the like. The frame 64 is made of a different material than the handle portion 26, and is preferably made of a high-strength material such as a metal, a metal composite, or another reinforcing material such as carbon fiber, a fiber-reinforced polymer, etc. The illustrated frame 64 is embedded (e.g., molded) within the handle portion 26, thereby allowing the walls of the handle portion 26 to be thinner while maintaining sufficient strength, thereby reducing the weight of the impact wrench 10 and providing more volume within the handle portion 26 to accommodate the first PCBA 63a. In the illustrated embodiment, the frame 64 extends from the battery receptacle 38 toward the switch 62 and at least partially beyond the switch.

[0087] In the illustrated embodiment, the frame 64 includes a central slot-shaped recess 65a extending along the length of the handle portion 26. The recess 65a provides additional clearance to accommodate electronic devices on the first PCBA 63a, such as one or more capacitors. The frame 64 also includes a plurality of circular recesses 65b arranged around the perimeter of the frame 64. The recesses 65b can provide flow channels for the polymer material of the handle portion 26 during molding of the handle portion 26, thereby further securing the frame 64 within the handle portion 26.

[0088] In the illustrated embodiment, Figure 5 As best shown in FIG. 4 , the clamshell halves 28a, 28b are positioned to at least partially overlap each other at the seam 31, and the grip portion 45 is formed to surround the mating clamshell halves 28a, 28b. Fasteners (e.g., fasteners 24) can be threaded, pinned, inserted, etc. into each of the clamshell halves 28a, 28b to further secure the housing 14 of the handle portion 26 in a closed or generally sealed position. In some embodiments, the fasteners 24 in the handle portion 26 can also extend through the frame 64.

[0089] Now refer to Figure 6 and Figure 7 , the battery socket 38 adjacent to the foot 40 and including the battery terminal 43 further includes a ramp or detent 68 configured to engage with the battery 34 when the battery 34 is coupled to the battery socket 38. In some embodiments, the detent 68 is made of a resilient elastomeric material (such as rubber). In other embodiments, the detent 68 can be spring biased into engagement with the battery 34. In the illustrated embodiment, one or more fillets 71 (such as an elastomeric plug or a rubber plug) can be inserted into a portion of the foot 40 near the front end of the battery socket 38. The detent 68 and the fillet 71 occupy the tolerance space between the battery 34 and the socket 38 to provide a close fit between the battery 34 and the socket 38.

[0090] In the illustrated embodiment, the battery receptacle 38 further includes a frame 69 supported (e.g., positioned, inserted, molded, formed, etc.) within the battery receptacle 38. The illustrated frame 69 is made of one or more metal stampings (or any other suitable high-strength material) and provides additional strength and durability to the rails 49 that slidably couple with and support the battery 34. Similar to the frame 64, the frame 69 can be embedded (e.g., molded) within the corresponding clamshell half 28a, 28b.

[0091] Now refer to Figures 2A to 3, the impact wrench 10 further includes a gear assembly 66 driven by the output shaft 50 and an impact mechanism 70 coupled to the output end of the gear assembly 66. The impact mechanism 70 may also be referred to herein as the drive assembly 70. The gear assembly 66 may be configured in any of a number of different ways to provide a speed reduction between the output shaft 50 and the input end of the drive assembly 70. The gear assembly 66 is at least partially housed within a gear box or gear housing 74 formed by the housing 14. Specifically, the clamshell halves 28a, 28b form a recess 75 that directly receives the gear assembly 66 and at least partially forms the gear housing 74. As will be described in more detail below, the gear assembly 66 and gear housing 74 of the impact wrench 10 further shorten the overall length of the impact wrench 10.

[0092] In the embodiments shown, specific reference is made to Figures 2A to 3 , the front end portion 78 of the motor housing portion 18 receives and overlaps a portion of the front housing portion 22. In the illustrated embodiment, the gear housing 74 and the front housing portion 22 may contain a lubricant, such as grease or oil, to assist in smooth operation of the impact wrench 10. As will be discussed in more detail below, the impact wrench 10 further includes a sealing system 80 that is at least partially positioned between the gear housing 74 and the front housing portion 22 to inhibit the lubricant from escaping from the front housing portion 22.

[0093] like Figure 3 As shown, the gear assembly 66 includes: a helical pinion 82 formed on the output shaft 50 of the motor 42; a plurality of helical planetary gears 86 meshing with the helical pinion 82; and a helical ring gear 90 meshing with the planetary gears 86 and rotationally fixed within the housing 14 (e.g., the gear housing 74). More specifically, the ring gear 90 shown includes a plurality of lugs 170 ( Figure 8 and Fig. 9 ). In the illustrated embodiment, the lugs 170 of the ring gear 90 fit within the grooves 75 formed by the clamshell halves 28a, 28b to support and rotationally constrain the ring gear 90. The rearwardly facing side of the ring gear 90 rests on the partition wall 113 formed by the clamshell halves 28a, 28b. The partition wall 113 separates the gear housing 74 from the motor 42.

[0094] Continue to refer to Figure 3 , the planetary gears 86 are coupled to a camshaft 94 of the drive assembly 70 such that the camshaft 94 acts as a planet carrier. Accordingly, rotation of the output shaft 50 rotates the planetary gears 86, which then travel along the inner circumference of the ring gear 90, thereby rotating the camshaft 94. In the illustrated embodiment, the camshaft 94 includes a through hole 96 extending through the camshaft 94 along the axis 54 ( Figure 3). The through hole 96 is shaped to accommodate and / or receive at least a portion of the helical pinion 82. In the illustrated embodiment, the through hole 96 extends through the entire length of the camshaft 94, which reduces the weight of the camshaft 94; however, in other embodiments, the through hole 96 may only extend partially through the camshaft 94.

[0095] refer to Figure 2A and Figure 3 , the output shaft 50 is rotatably supported by a first or front bearing 98 and a second or rear bearing 102. The output shaft 50 extends through an opening in the partition wall 113. The helical-type gears / pinions 82, 86, 90 of the gear assembly 66 may advantageously provide higher torque capacity and quieter operation than spur gears, for example, but the helical engagement between the helical pinion 82 and the planetary gears 86 produces an axial thrust load on the output shaft 50. Accordingly, the impact wrench 10 includes a hub or bearing retainer 106 integrally formed with the end cap 30 that secures the rear bearing 102 both axially (e.g., to resist forces transmitted along the axis 54) and radially (i.e., to resist forces transmitted in a radial direction of the output shaft 50).

[0096] refer to Figure 3 , the fan 58 includes a frustoconical recess 114, and the bearing retainer 106 extends into the frustoconical recess 114 such that at least a portion of the bearing retainer 106 and at least a portion of the rear bearing 102 overlap the fan 58 along the axis 54. This overlapping arrangement advantageously reduces the axial length of the impact wrench 10.

[0097] Now refer to Figure 2A and Fig. 9 , the front bearing 98 supports the output shaft 50, and because the motor 42 does not require a sensor plate on its front face, the front bearing 98 can be axially recessed into the stator 46. In the illustrated embodiment, the ring gear 90 includes a boss that extends rearwardly through an opening in the partition wall 113 and forms a bearing support 115 that receives and supports the front bearing 98. In other words, the front bearing 98 is coupled to and supported by the ring gear 90 (e.g., at an outer race of the front bearing 98) so that a portion of the ring gear 90 extends between the housing 14 and the front bearing 98 in a radial direction of the bearing 98. In this way, the housing 14, the ring gear 90, the front bearing 98, and the output shaft 50 each overlap along the axis 54. In other words, at least one line LL ( LL ) can be drawn from the output shaft 50 in a radially outward direction that intersects the front bearing 98, the stator 46, and the bearing support 115 of the ring gear 90. Fig. 9 ). This overlapping arrangement advantageously reduces the axial length of the impact wrench 10 and is facilitated by the absence of a sensor plate at the front side of the motor 42 .

[0098] like Figure 2C As shown, the stator 46 has an outer diameter C1, and the front bearing 98 and the rear bearing 102 are separated by a distance C2. More specifically, the distance C2 is measured between the front end of the rear bearing 102 and the rear end of the front bearing 98. In the illustrated embodiment, the distance C2 between the bearings 98, 102 is less than the diameter C1 of the stator 46. In some embodiments, the diameter C1 of the stator 46 can be 50mm to 70mm, 50mm to 60mm, 55mm to 60mm, or 50mm to 55mm. Therefore, the motor 42 has a relatively large diameter to length ratio, allowing the motor 42 to supply a relatively large amount of power within a relatively compact overall length.

[0099] Now refer to Figure 2A and Figure 3 The drive assembly 70 of the impact wrench 10 is described. The drive assembly 70 includes an anvil 126 extending from the front housing portion 22 to which a tool element (not shown) can be coupled to perform work on a workpiece (e.g., a fastener). The drive assembly 70 is configured to convert a constant rotational force or torque provided by the gear assembly 66 into an impact rotational force or torque intermittently applied to the anvil 126 when a reaction torque on the anvil 126 (e.g., due to engagement between the tool element and the fastener being performed) exceeds a certain threshold. In the illustrated embodiment of the impact wrench 10, the drive assembly 70 includes a camshaft 94, a hammer 130 supported on the camshaft 94 and axially slidable relative to the camshaft, and the anvil 126. In other words, the hammer 130 is configured to reciprocate axially along the camshaft 94 to apply a rotational impact to the anvil 126 in response to rotation of the camshaft 94.

[0100] The through hole 96 of the cam shaft 94 extends into the anvil 126 (e.g., into a hole, recess, etc.) and leads to an anvil ball 128 positioned within the anvil 126. The cam shaft 94 contacts the anvil ball 128 so that the anvil ball 128 provides a wear-resistant contact between the cam shaft 94 and the anvil 126 to prevent excessive wear of the anvil. In some embodiments, the anvil ball 128 has a diameter of approximately 5.00 mm to 15.00 mm. In the illustrated embodiment, the anvil ball 128 has a diameter of approximately 10.00 mm.

[0101] Continue to refer Figure 2A and Figure 3 The drive assembly 70 further includes a spring 134 that forces the hammer 130 toward the front of the impact wrench 10 (e.g., Figure 2A In other words, the spring 134 biases the hammer 130 in the axial direction along the axis 54 toward the anvil 126. The thrust bearing 138 (see also Figure 8) and thrust washer 142 are positioned between the spring 134 and the hammer 130. The thrust bearing 138 and thrust washer 142 allow the spring 134 and camshaft 94 to continue to rotate relative to the hammer 130 after each impact stroke when a lug (not shown) on the hammer 130 engages a corresponding anvil lug 146 and rotation of the hammer 130 stops momentarily.

[0102] The cam shaft 94 further includes cam grooves 150 in which corresponding cam balls 154 are received. The cam balls 154 are in driving engagement with the hammer 130 and movement of the cam balls 154 within the cam grooves 150 allows relative axial movement of the hammer 130 along the cam shaft 94 when the hammer and anvil lugs 146 engage and the cam shaft 94 continues to rotate.

[0103] In the illustrated embodiment, continue to refer to Figure 2A and Figure 3 , the impact wrench 10 further includes a bushing 158 supported by the housing 14 between the camshaft 94 and the gear assembly 66. The bushing 158 receives a washer or wear ring 162 that is positioned in a relief space or annular groove formed by the rear end portion of the camshaft 94. Just as the gear assembly 66 is supported in the groove 75 formed by the clamshell halves 28a, 28b, the bushing 158 is supported in the groove 166 formed by the clamshell halves 28a, 28b. In other words, each of the first and second housing portions 28a, 28b forms a first groove (e.g., groove 75) configured to directly receive the gear assembly 66 and a second groove (e.g., groove 166) configured to directly receive the bushing 158. The bushing 158 is thus positioned in the housing 14 and constrained by the housing to absorb the rearward force generated by the spring 134 against the camshaft 94. In some embodiments, the bushing 158 can abut the front surface of the ring gear 90.

[0104] While typical impact-type power tools include camshaft bearings to rotationally support the camshaft within the gearbox, in the illustrated embodiment, the cantilevered planetary gear 86 radially supports and the bushing 158 axially supports the rear end of the camshaft 94, which reduces the overall length of the impact wrench 10 relative to such typical power tools. Specifically, such bearings of typical impact-type power tools include spheres that are contained between inner and outer races, such that the bearings must be at least as long or as wide as the diameter of the spheres. These bearings also require support from the bearing retainer, which even further increases the depth or length of the bearing assembly and, therefore, the tool. Avoiding such camshaft bearings can also increase the torque-to-length ratio of the impact wrench 10 and reduce its overall weight relative to typical impact-type power tools.

[0105] Now refer to Figures 8 to 10, the bushing 158 includes a plurality of lugs 174. The lugs 174 of the bushing 158 fit within the grooves 166 of the housing 14 and provide a rigid base for the axial load or force applied by the spring 134. In the illustrated embodiment, the bushing 158 includes four lugs 174 that are equally positioned around the circumference of the bushing 158 to support the bushing 158 in the housing 14.

[0106] like Figure 8 As further shown, the plurality of planetary gears 86 are connected by one or more pins 178 (see also Fig.11 ) is coupled to the first end 94a of the camshaft 94, and the one or more pins extend through the aperture 182 of the bushing 158. In other words, the pins 178 pass through the aperture 182 of the bushing 158 from the planetary gear 86 to the camshaft 94 without contacting the bushing 158. The second end 94b of the camshaft 94 is supported by the anvil 126, which is retained in the front housing portion 22 by an anvil bushing 186 (see also Figure 2A ).

[0107] Now refer to Figures 8 to 14 , the sealing systems 80, 80' will be described in more detail. Figure 8 The illustrated sealing system 80, which may also be referred to as the sealing assembly 80, includes a rear sealing portion 190, a middle sealing portion 194, and a front portion of a front sealing portion 198. In some embodiments, each sealing portion 190, 194, 198 is made of a flexible / semi-flexible polymer material (e.g., rubber, neoprene, silicone, etc.). Generally, the sealing assembly 80 defines a sealing chamber 200 ( Fig.11 and Fig.12 ), the sealing chamber contains lubricant between the first end 80a and the second end 80b of the sealing system 80. Fig.11 and Fig.12 As shown, the chamber 200 is at least partially defined by the housing 14 (eg, the motor housing 18 ) and the front housing portion 22 .

[0108] Specific reference Fig. 9 and Fig.10 , the first end 80a of the sealing system 80 is generally adjacent to the bushing 158 and the ring gear 90 (e.g., the first end 94a of the camshaft 94), while the second end 80b is positioned adjacent to the anvil 126 and the anvil bushing 186. In the illustrated embodiment, the rear seal portion 190 at least partially surrounds the ring gear 90 and extends into a slot or groove 204 formed in each of the clamshell halves 28a, 28b. For example, the groove 204 can be partially formed in the first clamshell half 28a and partially formed in the second clamshell half 28b, so that the seam 31 where the clamshell halves 28a, 28b contact each other is at least sealed closed by the rear seal portion 190.

[0109] In the illustrated embodiment, at least a portion of the rear seal portion 190, and thus the groove 204, forms an L-shape as it extends through the housing 14. The rear seal portion 190 can be compressed, stretched, and / or otherwise retained around the gear assembly 66 to inhibit lubricant from migrating out of the gear housing 74 (e.g., out of the housing 14, into the motor housing 18, into the handle portion 26, etc.). The upper extension of the rear seal portion 190 can inhibit lubricant from escaping from the impact wrench 10 through the clamshell halves 28a, 28b (e.g., through the seam 31), while the lower extension of the rear seal portion 190 can inhibit lubricant from migrating into the handle portion 26 (e.g., through the seam 31). In some embodiments, the rear seal portion 190 can be fed or pressed into the groove 204 during assembly of the impact wrench 10.

[0110] In the illustrated embodiment, the L-shaped portion of the rear seal portion 190 extends around the groove 166 of the gear assembly 66 (eg, around the ring gear 90 and / or surrounds the ring gear) to further seal the gear assembly 66. Fig.12 As shown, the rear seal portion 190 is formed of two separate portions 190a, 190b that each extend around a portion of the ring gear 90 and extend in the L-shaped groove 204. Forming the rear seal portion 190 as two separate portions 190a, 190b facilitates manufacturing (e.g., assembly, forming, etc.) of the impact wrench 10 so that the rear seal portion 190 can be coupled (e.g., connected, inserted, etc.) to the impact wrench 10 from opposite sides or ends of the impact wrench 10. In other words, the two separable portions 190a, 190b of the rear seal portion 190 are generally mirror images relative to each other about the axis 54. In the illustrated embodiment, the rear seal portion 190 includes a plurality of 90 degree offsets, one offset between the ring gear 90 and the motor housing 18, and another offset within the groove 204 (e.g., in the L-shaped portion of the groove 204).

[0111] like Fig.10 As best shown, the rear sealing portion 190 and the groove 204 can extend into the front end portion 78 and the front housing portion 22. The rear sealing portion 190 can further contact (e.g., press against, abut, etc.) the middle sealing portion 194. In the illustrated embodiment, the middle sealing portion 194 is a flexible (e.g., compressible, stretchable, etc.) O-ring 194. The O-ring 194 can be stretched around the rim 208 of the front housing portion 22. In the illustrated embodiment, as shown Fig.10As shown, the rim 208 is positioned to overlap with the front end portion 78 of the housing 14, and the O-ring 194 is compressed and / or positioned between the rim 208 and the front end portion 78 to seal the housing 14 and the front housing portion 22 together. In other words, the rim 208 and the front end portion 78 can overlap each other circumferentially so that the O-ring 194 can contribute to the circumferential seal between the motor housing 18 / gear housing 74 and the front housing portion 22.

[0112] like Fig.10 and Fig.11 As emphasized, the planetary gears 86 can be mounted on the ring gear (in Fig.10 The housing 18 is concealed in the recess 210 such that lubricant is generally allowed to reach the planetary gears 86, the pinion gears 82, the ring gear 90, and the pins 178 within the gear assembly 66, but not rearwardly beyond the ring gear 90. In the illustrated embodiment, the O-ring 194 is positioned between the front housing portion 22 and the motor housing 18 to seal the middle portion of the chamber 200, which is generally located between the first end 80a and the second end 80b of the sealing system 80.

[0113] refer to Figures 9 to 11 , each of the fasteners 24 can be threaded into an insert 212 formed in the motor housing 18. In the illustrated embodiment, the insert 212 and the fasteners 24 are made of metal (such as steel, stainless steel, aluminum, and / or the like). In some embodiments, the fasteners 24 are M6 machine screws with hexagonal head caps that can be threaded into the inserts 212. When fastened (e.g., threaded) together, the fasteners 24 draw the motor housing 18 and the front housing portion 22 together to compress or abut the O-ring 194. Thus, the motor housing 18 and the front housing portion 22 can be coupled together around a portion of the sealing system 80 to inhibit lubricant from escaping the housing 14 from, for example, between the motor housing 18 and the front housing portion 22.

[0114] In the illustrated embodiment, the motor housing 18 and the handle portion 26 include a rigid polymer or plastic material, and the front housing portion 22 is metal. Thus, the sealing system 80 seals together two housings (e.g., the motor housing 18 and the front housing portion 22) formed of different materials. In the illustrated embodiment, the motor housing 18 and the gear housing 74 are made of a first polymer material, while the front housing portion 22 is made of metal. In some embodiments, the portion of the motor housing 18 that supports the gear assembly 66 (e.g., the gear housing 74) may include additional and / or different composition materials (e.g., stronger) to support the gear assembly 66.

[0115] Specific reference Fig.11 and Fig.12, the front seal portion 198 is retained between the anvil bushing 186 and the seal retainer 216. For example, the front housing portion 22 may include a plug, an insert, a ridge, etc. that acts as a seal retainer 216 to prevent the front seal portion 198 from moving in the front housing portion 22. In the illustrated embodiment, the seal chamber 200 is defined between the ring gear 90 (e.g., at the rear end 80a) and the seal retainer 216 (e.g., at the front end 80b). In other words, the rear seal portion 190 inhibits lubricant from migrating axially rearward along the gear assembly 66 and radially out of the housing 14, while the front seal portion 198 inhibits lubricant from migrating axially forward from the front seal portion 198 and / or the seal retainer 216. The front seal portion 198 can further reduce swinging or displacement of the anvil 126 to reduce sticking or damage to the anvil 126. As Fig.12 As best shown, the front seal portion 198, the o-ring 194, and the rear seal 190 may be discrete, disconnected, separate pieces, and / or the like.

[0116] In the illustrated embodiment, the seal assembly 80 is inserted into the housing 14 (e.g., the rear seal portion 190 and / or the intermediate seal portion 194) and / or the front housing portion 22 (e.g., the front seal portion 198) after the clamshell halves 28a, 28b are formed. For example, the clamshell halves 28a, 28b may be molded (e.g., blow molded, injection molded, etc.) with the groove 204 formed therein, and the rear seal portion 190 may then be secured in the groove 204. Similarly, the front housing portion 22 may be formed (e.g., machined, stamped, etc.), and the front seal portion 198 may then be inserted into the front housing portion 22 and positioned between the front housing portion 22 and the anvil 126. In some embodiments, at least a portion of the seal assembly 80 may be integrally formed (e.g., co-molded) with the clamshell halves 28a, 28b.

[0117] refer to Fig.13 and Fig.14 , an alternative seal assembly or sealing system 80' includes an alternative rear seal portion 190' and an intermediate seal portion 194' that can be used with the impact wrench 10 in substantially the same manner as the seal assembly 80. For example, the rear seal portion 190' can be inserted / compressed / sandwiched into a groove or recess 204 formed in the motor housing 18. Although not specifically shown, the rear seal portion 190' also includes a portion extending around or against the ring gear 90 like the rear seal portion 190.

[0118] like Fig.14As specifically shown in FIG. 1 , the rear seal portion 190′ can be coupled to a first intermediate seal portion 198a′ and a second intermediate seal portion 198b′, which are generally shaped to fit between the edge 208 of the front housing portion 22 and the front end portion 78 of the motor housing 18 ( Fig.10 ). In the illustrated embodiment, the rear seal portion 190' and the first and second intermediate seal portions 198a', 198b' are discontinuous with one another such that all three portions meet at a common coupling 226. In other embodiments, the rear seal portion 190' and the first and second intermediate seal portions 198a', 198b' may be coupled together before or after assembly with the impact wrench 10. In one application of the alternative seal assembly 80', the common coupling 226 may be used to seal at least a portion of the seam 31 of the clamshell halves 28a, 28b and at least a portion of the connection between the front housing portion 22 and the motor housing 18.

[0119] Reference now Fig.15 and Fig.16 According to one example configuration, the dimensions of the impact wrench 10 include a first length L1 defined axially between an end of the end cap 30 and an end of the switch 62. In the illustrated embodiment, the first length L1 may be between about 100.00 mm and about 120.00 mm (eg, 109.32 mm).

[0120] The impact wrench 10 can include a second length L2 defined axially between an end of the switch 62 and a tip of the anvil 126. In the illustrated embodiment, the second length L2 can be between about 60.00 mm and about 80.00 mm (eg, 69.40 mm).

[0121] The impact wrench 10 may further include a third length L3 defined axially between the tip of the anvil 126 and the first end of the ring gear 90 / camshaft 94. In the illustrated embodiment, the third length L3 may be between about 110.00 mm and about 130.00 mm (eg, 119.823 mm).

[0122] The impact wrench 10 may further include a fourth length L4 defined axially between the rearward end of the rear bearing 102 and the rearward end of the front bearing 98. In the illustrated embodiment, the fourth length L4 may be between about 40.00 mm and about 60.00 mm (eg, 49.60 mm).

[0123] The impact wrench 10 may also include a height H3 defined linearly between an end of the switch 62 (eg, generally at the center of the switch 62) and a bottom of the foot 40. In the illustrated embodiment, the height may be between about 110.00 mm and about 140.00 mm (eg, 127.19 mm).

[0124] like Fig.16 As shown, when the spring 134 is in an uncompressed or free state / condition, the impact wrench 10 can also include a fifth length L5 axially defined between the rear end of the camshaft 94 and the rear end of the hammer 130. In the illustrated embodiment, the fifth length L5 can be between about 10.00 mm and about 40.00 mm (e.g., 29.1295 mm).

[0125] Also like Fig.16 As shown, the stator 46 of the impact wrench 10 may have a dimension D1 (eg, when taken through the axis 54) defined linearly between the ends of the stator 46. In the illustrated embodiment, the dimension D1 may be between about 40.00 mm and about 80.00 mm (eg, 60.00 mm).

[0126] Therefore, the overall dimension ratio of the impact wrench 10 may be greater than about 2.0, where the dimension ratio may be defined by the following expression:

[0127]

[0128] This expressed overall dimension ratio can provide accurate / preferred driver, gear, and motor assemblies (e.g., drive assembly 70, gear assembly 66, motor 42 / motor assembly). The motor 42 and hammer 130 of the impact wrench 10 are compactly located in the housing 14 and closer to the handle portion 26 than a typical impact power tool. For example, the combined dimensions of the impact wrench 10 shown (e.g., L1, L2, L3, L4, L5, H3, and D1) are unknown in the art, allowing the impact wrench 10 to have advanced ergonomics without sacrificing operational capabilities (e.g., torque transfer, external dimensions, etc.).

[0129] In some embodiments, Fig.15 and Fig.16 As shown, the overall length OL of the impact wrench 10 can be between about 175.00 mm and about 205.00 mm (e.g., 187.96 mm), and the overall height OH of the impact wrench 10 can be between about 225.00 mm and about 255.00 mm (e.g., 234.95 mm). In the embodiment shown, the overall height OH is 1.25 times the overall length OL.

[0130] As described above, the features and dimensions of the impact wrench 10 make the impact wrench 10 both compact and lightweight. The impact wrench shown has a total weight (excluding the battery 34) of between 5.0 and 5.4 pounds in some embodiments, or between 5.0 and 5.2 pounds in some embodiments. In addition, in some embodiments, the impact wrench 10 is capable of delivering at least 1,000 ft-lb (foot-pounds) of tightening torque to a workpiece, or other embodiments deliver at least 1,100 ft-lb of tightening torque. Therefore, the impact wrench 10 is capable of delivering between 185 ft-lb and 220 ft-lb of tightening torque per pound of weight.

[0131] In operation of the impact wrench 10, the operator depresses the switch 62 to activate the motor 42, which continuously drives the gear assembly 66 and the camshaft 94 via the output shaft 50. The helical engagement between the helical pinion 82 and the planetary gears 86 generates a forwardly directed (e.g., toward the drive assembly 70) thrust load along the axis 54 of the output shaft 50 that is transmitted to the rear bearing 102, which is secured by the bearing retainer 106 and / or the housing 14 to resist this thrust load.

[0132] As the camshaft 94 rotates, the cam ball 154 drives the hammer 130 to rotate with the camshaft 94, and the driving surfaces of the hammer lugs respectively engage the driven surfaces of the anvil lugs 146 to provide impact and rotatably drive the anvil 126 and the tool element. After each impact, the hammer 130 moves or slides backward along the camshaft 94 away from the anvil 126, so that the hammer lugs are disengaged from the anvil lugs 146.

[0133] As the hammer 130 moves rearwardly, the cam ball 154 located in the corresponding cam groove 150 in the cam shaft 94 moves rearwardly in the cam groove 150. The spring 134 stores some of the rearward energy of the hammer 130, thereby providing a return mechanism for the hammer 130. After the hammer lugs are disengaged from the corresponding anvil lugs 146, as the spring 134 releases its stored energy, the hammer 130 continues to rotate and move or slide forward toward the anvil 126 until the driving surface of the hammer lug reengages the driven surface of the anvil lug 146 to cause another impact.

[0134] Fig.17A and Fig. 17B Another embodiment of an impact wrench 310 is shown. Fig.17A and Fig. 17B The impact wrench 310 of FIG. 1 is similar to the impact wrench 10 described above. As such, the following description focuses on the differences between the impact wrench 310 and the impact wrench 10. Additionally, features and elements of the impact wrench 10 may be incorporated into the impact wrench 310, or vice versa.

[0135] The impact wrench 310 includes a housing 314, a gear assembly 318, and a drive assembly including a camshaft 322, a hammer 326, an anvil 330, and a spring 334 that biases the hammer 326 toward the front of the impact wrench 310. The housing 314 includes a motor housing portion 338 (which may include a first housing portion and a second housing portion, similar to the motor housing portion 38) and an impact box or front housing portion 342 coupled to the motor housing portion 338. The gear assembly 318 includes a ring gear 346 and a plurality of planetary gears 386 meshing with the ring gear 346. The hammer 326 and the anvil 330 are disposed at the front end of the impact wrench 310 within the front housing portion 342.

[0136] In the illustrated embodiment, the ring gear 346 includes a flange 347 extending forward from the toothed portion 351 of the ring gear 346. The planetary gear 386 is engaged with the toothed portion 351, and the rear end of the camshaft 322 is rotatably supported by the flange 347. In this way, the camshaft 322 is partially nested in the ring gear 346. In some embodiments, a low-friction material (such as a camshaft 322) may be provided between the camshaft 322 and the toothed portion 351. or nylon) to support the rear end of the camshaft 322 against axial force.

[0137] The impact wrench 310 further includes an intermediate housing 350 disposed between the front housing portion 342 and the ring gear 346. More specifically, the rear end of the intermediate housing 350 is positioned adjacent to the ring gear 346, while the front end of the intermediate housing 350 is positioned adjacent to the front housing portion 342. In the illustrated embodiment, the intermediate housing 350 is cup-shaped and formed of plastic. In other embodiments, the intermediate housing may have other shapes and / or may be formed of different materials.

[0138] like Fig. 17B As best shown, the intermediate housing 350 receives a rear seal 354 at the rear end of the intermediate housing 350 and a front seal 358 at the front end of the intermediate housing 350. When the impact wrench 310 is assembled, the rear seal 354 is compressed between the rear end of the intermediate housing 350 and the ring gear 346 to form a seal between the intermediate housing 350 and the ring gear 346, while the front seal 358 is compressed between the front end of the intermediate housing 350 and the front housing portion 342 to form a seal between the intermediate housing 350 and the front housing portion 342. Thus, the intermediate housing 350, the ring gear 346, and the front housing portion or impact box 342 at least partially define a sealed chamber in which the gear assembly 318 and the drive assembly are disposed. By sealing between the ring gear 346 and the front housing portion 342, the intermediate housing 350 and the seals 354, 358 can inhibit grease / lubricant in the chamber from migrating into the motor housing portion 338.

[0139] Various features of the invention are set forth in the appended claims.

Claims

1. A power tool comprising: case; a motor mounted within the housing, the motor comprising a stator having a plurality of windings and a rotor having a shaft configured to rotate relative to the stator about an axis, wherein the stator defines an outer diameter; a gear assembly operably coupled to the motor, the gear assembly comprising a ring gear fixed relative to the housing and a plurality of planet gears meshing with the ring gear; a drive assembly operably coupled to the gear assembly to receive torque from the shaft through the gear assembly, the drive assembly comprising Camshaft, anvil, and a hammer configured to reciprocate along the cam shaft to apply a rotary impact to the anvil in response to rotation of the cam shaft; a rear bearing rotatably supporting a rear portion of the shaft; and a front bearing rotatably supporting a front portion of the shaft, Features: A distance measured between a front edge of the rear bearing and a rear edge of the front bearing is less than the outer diameter of the stator.

2. The power tool according to claim 1, wherein: The housing includes a first portion and a second portion coupled together at a seam, and an end cap coupled to the first portion and the second portion.

3. The power tool according to claim 2, wherein: The first portion and the second portion define a portion of a motor housing that directly supports the stator.

4. The power tool of claim 3, further comprising an impact box coupled to the housing, wherein: The impact box surrounds the drive assembly.

5. The power tool according to claim 4, further comprising an intermediate housing disposed between the motor housing portion and the impact box, wherein: The ring gear, the impingement box, and the intermediate housing at least partially define a sealed chamber that contains the gear assembly and the drive assembly.

6. The power tool according to claim 2, wherein: The rear bearing is supported by the end cover.

7. The power tool according to claim 1, wherein: The ring gear includes a boss extending rearwardly along the axis, and wherein the front bearing is received in and supported by the boss.

8. The power tool according to claim 1, wherein: The ring gear includes a toothed portion and a flange portion extending from the toothed portion, and wherein the flange portion rotatably supports the camshaft.

9. The power tool according to claim 1, wherein: The stator has an outer diameter of 50 mm to 70 mm.

10. The power tool of claim 1, further comprising a battery detachably coupled to the housing and configured to provide power to the motor.

11. A power tool comprising: A housing, the housing comprising a first housing portion and a second housing portion, the first housing portion and the second housing portion are both made of a polymer material, the first housing portion and the second housing portion are coupled together at a seam; a motor mounted within the housing between the first housing portion and the second housing portion, the motor comprising a shaft configured to rotate about an axis; Features: a gear box containing lubricant and integrally formed by the first housing portion and the second housing portion; a gear assembly supported within the gearbox and operably coupled to the motor, the gear assembly comprising a ring gear engaged with the gearbox, and a plurality of planetary gears meshing with the ring gear; a drive assembly operably coupled to the gear assembly, the drive assembly comprising Camshaft, anvil, and a hammer configured to reciprocate along the cam shaft to apply a rotary impact to the anvil in response to rotation of the cam shaft; an impact box made of a metal material and coupled to the housing, the impact box surrounding the drive assembly and containing a lubricant; and A seal prevents lubricant from migrating from the gear box and the impulse box.

12. The power tool according to claim 11, wherein: The first housing portion and the second housing portion define a slot, and wherein the ring gear is supported within the slot.

13. The power tool according to claim 12, wherein: The housing includes a dividing wall extending between the motor and the gear assembly, wherein a shaft of the motor extends through an opening in the dividing wall, and wherein the ring gear sits on the dividing wall.

14. The power tool according to claim 13, wherein: The ring gear includes a boss extending rearwardly along the axis, wherein the shaft of the motor is supported by a bearing received in the boss.

15. The power tool according to claim 11, wherein: The housing and the impingement box are coupled together by one or more fasteners, each of which is received in an insert secured within the housing and formed of a metallic material.

16. A power tool comprising: a housing including a first housing portion and a second housing portion coupled to the first housing portion, the first housing portion and the second housing portion contacting each other at a seam; a motor mounted directly within the housing between the first housing portion and the second housing portion; Features: a gear box, the gear box being integrally formed by the first housing portion and the second housing portion; a gear assembly supported within the gear housing and operably coupled to the motor; a drive assembly operably coupled to the gear assembly, the drive assembly comprising Camshaft, anvil, and a hammer configured to reciprocate along the cam shaft to apply a rotary impact to the anvil in response to rotation of the cam shaft; and an impact box coupled to the housing, the impact box enclosing the hammer and the anvil, the impact box having a first end facing the housing and a second end opposite the first end, the anvil extending through the second end of the impact box; wherein the impingement box and the gear box define a chamber containing a lubricant; and The power tool further comprises a sealing system, which is at least partially located between the gear box and the impact box to prevent lubricant from escaping from the chamber.

17. The power tool according to claim 16, wherein: The sealing system further comprises at least a first portion, a second portion, and a third portion, wherein the first portion, the second portion, and the third portion seal the chamber.

18. The power tool according to claim 17, wherein: The first portion of the sealing system is at least partially positioned between the first housing portion and the second housing portion, on the upper portion and the lower portion of the chamber.

19. The power tool according to claim 18, wherein: The gear assembly further includes Multiple planetary gears, and a ring gear surrounding the plurality of planetary gears, Wherein, the first portion surrounds the ring gear.

20. The power tool according to claim 19, wherein: A groove is formed between the first housing portion and the second housing portion, wherein the first part of the sealing system is received in the groove.

21. The power tool according to claim 20, wherein: A portion of the groove includes an L-shape, and wherein the first portion is received around the ring gear and in the groove.

22. The power tool according to claim 21, wherein: The first part of the sealing system comprises two mirror-image parts positioned opposite each other.

23. The power tool according to claim 17, wherein: The second portion of the sealing system is positioned adjacent to the first end of the impact box and the third portion of the sealing system is positioned adjacent to the second end of the impact box, wherein the second portion of the sealing system is retained between the impact box and the housing, and wherein the third portion of the sealing system is retained by a seal retainer surrounding the anvil.

24. The power tool according to claim 17, wherein: The housing includes a front end portion, and the impingement box includes a rim received within and overlapping the front end portion, and wherein the second portion of the sealing system includes an O-ring sandwiched between the front end portion of the housing and the rim.

25. The power tool according to claim 17, wherein: The first, second and third parts of the sealing system are formed as separate pieces, the first part being located between the gear assembly and the housing to seal the rear end of the chamber, the second part being located between the impact box and the housing to seal the middle part of the chamber, wherein the third part of the sealing system is located between the drive assembly and the impact box to seal the front part of the chamber, and wherein the first part of the sealing system extends between the rear end of the chamber to the middle part of the chamber.

26. A power tool comprising: A housing, the housing comprising a first housing portion and a second housing portion, the first housing portion and the second housing portion are both made of a polymer material, the first housing portion and the second housing portion are coupled together at a seam; a motor mounted within the housing between the first housing portion and the second housing portion, the motor comprising a shaft configured to rotate about an axis; Features: a gear box containing lubricant and integrally formed by the first housing portion and the second housing portion; a gear assembly supported within the gearbox and operably coupled to the motor, the gear assembly comprising a ring gear engaged with the gearbox, and a plurality of planetary gears meshing with the ring gear; a drive assembly operably coupled to the gear assembly, the drive assembly comprising Camshaft, anvil, and a hammer configured to reciprocate along the cam shaft to apply a rotary impact to the anvil in response to rotation of the cam shaft; an impact box made of a metal material and coupled to the housing, the impact box surrounding the drive assembly and containing a lubricant; and A seal prevents lubricant from migrating from the gear box and the impulse box.

27. The power tool according to claim 26, wherein: The first housing portion and the second housing portion define a slot, and wherein the ring gear is supported within the slot.

28. The power tool according to claim 27, wherein: The housing includes a dividing wall extending between the motor and the gear assembly, wherein a shaft of the motor extends through an opening in the dividing wall, and wherein the ring gear sits on the dividing wall.

29. The power tool according to claim 28, wherein: The ring gear includes a boss extending rearwardly along the axis, wherein the shaft of the motor is supported by a bearing received in the boss.

30. The power tool of claim 26, wherein: The housing and the impingement box are coupled together by one or more fasteners, each of which is received in an insert secured within the housing and formed of a metallic material.

31. A power tool comprising: a housing comprising a first housing portion and a second housing portion coupled together at a seam; a motor mounted in the housing and comprising an output shaft rotatable about an axis; an impact box coupled to the housing; an impact mechanism at least partially supported within the impact box, the impact mechanism comprising Camshaft, anvil, and a hammer configured to reciprocate along the cam shaft to apply a rotary impact to the anvil in response to rotation of the cam shaft; a gear assembly supported within the housing and operably coupled to the output shaft, the gear assembly comprising a plurality of planetary gears surrounding a portion of the output shaft, and a ring gear surrounding the plurality of planetary gears; as well as Features: A bushing is supported by the housing between the camshaft and the gear assembly, wherein the plurality of planetary gears are coupled to the camshaft by one or more pins such that the plurality of planetary gears are cantilevered on the camshaft.

32. The power tool according to claim 31, wherein: Each of the first housing portion and the second housing portion forms a first groove configured to directly receive the gear assembly and a second groove configured to directly receive the bushing, wherein the first groove and the second groove are offset relative to each other along the axis.

33. The power tool according to claim 32, wherein: The first groove receives the ring gear, and wherein the ring gear includes one or more lugs that contact the housing to inhibit rotational movement of the ring gear relative to the housing.

34. The power tool according to claim 33, wherein: The second groove receives a bushing, and wherein the bushing includes one or more lugs that contact the housing to inhibit rotational movement of the bushing relative to the housing.

35. The power tool of claim 34, wherein: The bushing includes at least four lugs.

36. The power tool of claim 34, wherein: The bushing at least partially supports the camshaft in the housing, and wherein the one or more pins pass through an aperture of the bushing between the planetary gears and the camshaft.

37. A power tool comprising: a housing including a motor housing portion and a handle housing portion extending from the motor housing portion, wherein the housing is formed from a molded polymer material; a motor supported within the motor housing portion; a trigger supported by the handle housing portion, the trigger being configured to operate the motor; a battery receptacle configured to receive a battery pack removably connectable to the power tool, the battery receptacle including one or more support rails formed into the battery receptacle; A PCBA, the PCBA being located within the handle housing portion and being in electrical communication with the motor assembly, the trigger, and the battery receptacle; Features: a frame formed within the handle housing portion and at least partially surrounding the PCBA, the frame being configured to reinforce the handle housing, The frame is made of a material different from that of the shell.

38. The power tool of claim 37, further comprising a grip overmolded onto the handle housing portion, the grip being configured for grasping by a user during operation of the power tool.

39. The power tool of claim 37, wherein: The frame includes a plurality of frame members molded into the handle housing portion.

40. The power tool of claim 39, wherein: The plurality of frame members extend between the battery receptacle and the trigger.

41. The power tool of claim 40, wherein: The plurality of frame members extend from the battery receptacle and beyond the trigger.

42. The power tool of claim 39, wherein: Each of these frame members is made of metal.

43. The power tool of claim 42, wherein: Each of the frame members includes a plurality of apertures.

44. The power tool of claim 43, wherein: One of the plurality of frame members includes a slot for receiving an electronic component mounted to the PCBA.

45. The power tool of claim 37, wherein: The frame is a first frame, wherein the power tool further includes a second frame molded into the battery receptacle, and wherein the second frame is made of a different material than the housing.

46. ​​The power tool of claim 45, wherein: The second frame is made of metal.

47. The power tool of claim 46, wherein: The second frame reinforces the track of the battery socket.

48. The power tool of claim 46, wherein: The first frame and the second frame each comprise metal stampings.

49. The power tool of claim 37, wherein: The battery receptacle includes an elastomeric element engageable with the battery pack when the battery pack is coupled to the power tool.

50. The power tool of claim 49, wherein: The elastomeric element is one of a plurality of elastomeric elements located in the battery receptacle and capable of engaging with the battery pack.

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