Power tool with closed gear housing

Abstract

A power tool comprising a housing having a first housing portion and a second housing portion, the first housing portion and the second housing portion together defining a head housing portion. The power tool further comprises a motor held within the head housing portion and including an output shaft, a gear housing fully enclosed by the head housing portion, a gear assembly engaged with the output shaft and held within the gear housing portion, and a drive assembly driven by the gear assembly and held within the head housing portion.

Description

Cross-reference to related applications

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 567,262, filed March 19, 2024, the entire contents of which are incorporated herein by reference. Area

[0002] The present disclosure relates to power tools and, more particularly, to rotary impact tools. background

[0003] Rotating impact tools are typically used to apply a percussive rotational force or intermittent torque to a tool element or workpiece (e.g., a fastener) to either tighten or loosen the fastener. Overview

[0004] The present disclosure, in one aspect, provides a power tool comprising a housing having a first housing portion and a second housing portion, the first housing portion and the second housing portion together defining a head portion. The power tool further comprises a motor supported within the head housing portion and including an output shaft, a gear housing completely enclosed by the head housing portion, a gear assembly engaged with the output shaft and supported within the gear housing portion, and a drive assembly driven by the gear assembly and supported within the head housing portion.

[0005] Another aspect of the present disclosure is a power tool comprising a housing defining a head housing portion, a motor supported within the head housing portion and having an output shaft defining an axis, a gear housing aligned with the motor along the axis and supported within the head housing portion, and an assembly engaging the output shaft and supported within the gear housing. The gear assembly includes a pinion gear coupled to the output shaft, a plurality of planetary gears meshing with the pinion gear, and a ring gear meshing with the planetary gears. The power tool further includes a seal axially disposed between the gear housing and the ring gear, and a drive assembly driven by the planetary gears and supported within the head housing portion.

[0006] The present disclosure provides, in another aspect, a power tool comprising a housing having a first housing portion, a second housing portion coupled to the first housing portion, the first and second housing portions defining a head housing portion, and a nose cap coupled to the head housing portion. The power tool further includes a motor supported within the head housing portion, a gear housing supported by the head housing portion, the nose cap coupled to the gear housing, a gear assembly engaged with the motor and supported within the gear housing, and a drive assembly driven by the gear assembly and supported within the head housing portion.

[0007] Further aspects of the invention will become apparent upon consideration of the detailed description and the accompanying drawings. Short description of the drawings Fig. 1 is a perspective view of a power tool according to an embodiment of the disclosure. Fig. 2 is a cross-sectional view of the power tool taken along line 2-2 of Fig. 1. Fig. 3 is an exploded view of the power tool showing the shell halves and a gear housing.

[0008] Before any embodiments of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure may be practiced or carried out in other embodiments and in various ways. It is also to be understood that the phraseology and terminology used herein is for the purpose of description and should not be considered limiting. Detailed description

[0009] Fig. Figure 1 shows an embodiment of a power tool in the form of a rotary impact tool, more specifically, an impact wrench 10. The impact wrench 10 includes a housing 14 having a head housing portion 18, a front nose cap 22 adjacent to the head housing portion 18, and a handle housing portion 26 extending downwardly from the head housing portion 18. In the illustrated embodiment, the handle housing portion 26 and the head housing portion 18 are defined by cooperating first and second shell halves or housing portions 28a, 28b.

[0010] The illustrated housing 14 also includes a rear end portion 30 defining a rear end of the head housing portion 18 opposite the front nose cap 22. The shell halves 28a, 28b may be coupled (e.g., attached) together at an interface or seam 31. In the illustrated embodiment, the seam 31 extends through the rear end portion 30 such that the shell halves 28a, 28b partially form the rear end portion 30. In other embodiments, the rear end portion 30 may be a separate component coupled to the shell halves 28a, 28b.

[0011] With reference to Fig. 1 and Fig. 2, the impact wrench 10 includes a battery 34 releasably coupled to a battery receptacle 38, which in the illustrated embodiment includes a cavity 40 extending into the handle housing portion 26. A motor 42 is held in the head housing portion 18 and receives power from the battery 34 via connections, contact pads, and / or battery terminals in the battery receptacle 38 when the battery 34 is coupled to the battery receptacle 38. In the illustrated embodiment, the handle housing portion 26 of the shell halves 28a, 28b may be covered or surrounded by a grip portion 45, which may be overmolded onto the handle housing portion 26 and around the rear end portion 30.

[0012] The battery 34 may be a power tool battery used primarily for operating a power tool, such as an electric drill, an electric saw, and the like (such as a 12-volt rechargeable battery). The battery 34 may comprise lithium-ion (Li-ion) cells. The 12-volt nominal voltage of the battery 34 provides an optimal balance between weight / size and power in the illustrated impact wrench 10; however, batteries with other nominal voltages may be used in other embodiments.

[0013] With reference to Fig. 2, the motor 42 in the illustrated embodiment is a brushless direct current ("BLDC") motor having a stator 46 and a rotor with an output shaft 50 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 airflow for cooling the motor 42 and / or other components of the power tool 10.

[0014] As in Fig. 2, the impact wrench 10 further includes a trigger 62 (including an actuator and a trigger switch) supported by the housing 14 and operable to selectively electrically connect the motor 42 (e.g., via suitable control circuitry provided on one or more printed circuit boards (“PCBAs”)) and the battery 34 to supply DC power to the motor 42. In other embodiments, the impact wrench 10 may include a power cord to connect the trigger 62 and the motor 42 to an AC power source. As a further alternative, the impact wrench 10 may be configured to operate with another power source (e.g., a pneumatic or hydraulic power source, etc.).

[0015] In the illustrated embodiment, a PCBA 65 is housed within the head housing portion 18 near a forward end of the stator 46. The illustrated PCBA 65 extends perpendicular to the axis 54 and includes one or more Hall-effect sensors that provide feedback for controlling the motor 42. The PCBA 65 is in electrical communication with the motor 42, the trigger 62, and the terminals of the battery receptacle 38. In the illustrated embodiment, the PCBA 65 includes a plurality of semiconductor switching elements (e.g., MOSFETs, IGBTs, or the like) that control and distribute power to the windings in the stator 46 to effect rotation of the rotor and the output shaft 50. The PCBA 65 may also include one or more microprocessors, machine-readable, non-transferable memory elements, and other electrical or electronic elements to control the operation of the impact wrench 10.

[0016] As in Fig. 2 and Fig. 3, the impact wrench 10 further includes a gear assembly 66 driven by the output shaft 50 and an impact mechanism 70 coupled to an output of the gear assembly 66. The impact mechanism 70 may also be referred to herein as a drive assembly 70. The gear assembly 66 may be configured in various ways to achieve a speed reduction between the output shaft 50 and an input of the drive assembly 70. The gear assembly 66 and the drive assembly 70 are housed in a gear housing 76, which in turn is disposed within the housing 14. The illustrated gear housing 76 is aligned with the motor 42 along the axis 56. The gear housing 76 is enclosed within the head housing portion 18 of the housing 14.In particular, the shell halves 28a, 28b collectively enclose the gear housing 76 such that no portion of the gear housing 76 is exposed or visible from the exterior of the impact wrench 10. In other words, the gear housing 76 is completely enclosed by the shell halves 28a, 28b. In other words, the gear housing 76 is held directly within the shell halves 28a, 28b. The gear housing 76 includes a front gear housing 77 having tabs 78 that extend radially outward from the exterior of the front gear housing 77 in a direction perpendicular to the axis 56. In other words, the tabs 78 extend toward and engage the recesses 80 (only one of which is shown) in the shell halves 28a, 28b to prevent rotation of the front gear housing 77 relative to the shell halves 28a, 28b (. Fig. 3). The front gear housing 77 further includes a projection 81 extending radially outward from the outside of the front gear housing 77 in a direction perpendicular to the axis 56. In other words, the projection 81 extends toward and engages a recess 83 in the front nose cap 22 to prevent rotation of the front gear housing 77 relative to the nose cap 22 ( Fig. 3).

[0017] With continued reference to Fig. 2 and Fig. 3, the impact wrench 10 includes a ring gear 90 that is part of the gear assembly 66. In some embodiments, the ring gear 90 may define the rear end of the gear housing 76. The gear assembly 66 includes a pinion 82 coupled to the output shaft 50 of the motor 42 and a plurality of planetary gears 86 that mesh with the pinion 82. The ring gear 90 meshes with the planetary gears 86 and is rotationally fixed in the housing 14. A rear surface of the ring gear 90 abuts a partition wall 92 formed by the shell halves 28a, 28b ( Fig. 3). In particular, the rear surface of the ring gear 90 includes a projection 100 that fits into a corresponding opening 101 in the partition wall 92 of the shell halves 28a, 28b. The projection 100 extends in a direction along the axis 54. The partition wall 92 separates the transmission housing 76 from the motor 42.

[0018] The planetary gears 86 are coupled to a camshaft 94 of the drive assembly 70, so that the camshaft 94 acts as a planetary carrier. Accordingly, the rotation of the output shaft 50 rotates the planetary gears 86, which then move along the inner circumference of the ring gear 90, thereby rotating the camshaft 94.

[0019] The output shaft 50 is rotatably supported in a first or front bearing 98 and a second or rear bearing 102. The pinion 82 coupled to the output shaft 50 projects through an opening in the partition 92. The impact wrench 10 has a hub or bearing retainer 106 formed by the shell halves 28a, 28b, which secures the rear bearing 102 both axially (for example, against forces exerted along the axis 54) and radially (i.e., against forces exerted in the radial direction of the output shaft 50). In the illustrated embodiment, the fan 58 has a recess 108, and the bearing retainer 106 extends into the recess 108 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 ( Fig. 2). This overlapping arrangement advantageously reduces the axial length of the impact wrench 10.

[0020] The drive assembly 70 of the impact wrench 10 will now be described with reference to Fig. 2. The drive assembly 70 is disposed within the gear housing 76. The drive assembly 70 includes an anvil 126 extending from the front nose cap 22 and to which a tool element (e.g., an insert, not shown) can be coupled to perform work on a workpiece (e.g., a fastener). The drive assembly 70 is configured to convert the constant rotational force or torque provided by the gear assembly 66 into a percussive rotational force or intermittent applications of torque to the anvil 126 when the reaction torque on the anvil 126 (e.g., due to engagement between the tool element and a fastener being machined) exceeds a certain threshold.In the illustrated embodiment of the impact wrench 10, the drive assembly 70 includes the camshaft 94, a hammer 130 mounted on the camshaft 94 and axially movable relative thereto, and the anvil 126. In other words, the hammer 130 is configured to reciprocate axially along the camshaft 94 and to apply periodic rotary impacts to the anvil 126 in response to the rotation of the camshaft 94. The anvil 126 is thus driven by the hammer 130 and is rotatably mounted in the gear housing 76 via a bushing 110. In other embodiments, the impact wrench 10 may also include other types of drive assemblies (for example, an oil pulse drive assembly having an oil-filled cylinder driven by the gear assembly 66 and having internal projections configured to strike the blades of an anvil extending into the cylinder).

[0021] In the embodiment shown, the bushing 110 has a knurled outer surface that is connected to the gear housing 76. In other embodiments, the bushing 110 ( Fig. 2) be coupled to the gear housing 76 with a thread, interference fit, or other means. The bushing 110 includes a groove 114 on the inside that receives a lubricant, such as grease or oil, for coating the anvil 126 to promote smooth operation of the impact wrench 10 by minimizing friction between the moving components. The front nose cap 22 encloses the anvil 126 and snaps onto the forwardmost portion of the gear housing 76.

[0022] The shell halves 28a, 28b further secure the front nose cap 22 to the housing 14 to prevent detachment from the gear housing 76. Specifically, at least a portion of the front nose cap 22 is disposed between the gear housing 76 and the head housing portion 18 in a direction perpendicular to the axis 56.

[0023] The drive assembly 70 also includes a spring 134 that biases the hammer 130 toward the front of the impact wrench 10. In other words, the spring 134 biases the hammer 130 in an axial direction toward the anvil 126 along the axis 54. A thrust bearing 138 is located between the spring 134 and the hammer 130. The thrust bearing 138 allows the spring 134 and the camshaft 94 to continue rotating relative to the hammer 130 after each impact when the lugs 140 ( Fig. 3) on the hammer 130 engage the corresponding anvil lugs 142 and the rotation of the hammer 130 stops momentarily. The camshaft 94 has grooves 150 in which corresponding cam balls 154 are received (although in Fig. 2 (only one cam ball is shown). The cam balls 154 are in driving engagement with the hammer 130, and the movement of the cam balls 154 in the grooves 150 allows relative axial movement of the hammer 130 along the camshaft 94 when the hammer lugs 140 and the anvil lugs 142 are engaged and the camshaft 94 continues to rotate. The axial movement of the hammer 130 compresses the spring 134, which then releases its stored energy to drive the hammer 130 forward and rotate the hammer 130 once the hammer lugs 140 release the anvil lugs 142.

[0024] With reference to Fig.2, the gear housing 76 may contain a lubricant, such as grease or oil, coated on the gear assembly 66 and / or the drive assembly 70 to promote smooth operation of the impact wrench 10 by minimizing friction between the moving components. In the illustrated embodiment, the impact wrench 10 includes a seal 156 that prevents lubricant from leaking from the gear housing 76. The seal 156 is disposed between the ring gear 90 and the gear housing 76 in a direction parallel to the axis 56. The seal 156 is disposed adjacent the ring gear 90 and couples to the front gear housing 77. In particular, the seal 156 abuts the ring gear 90 and is U-shaped in cross-section to receive a rim or flange 160 of the front gear housing 77 to prevent lubricant from leaking from the gear housing 76.The illustrated seal 156 is made of a flexible, elastomeric material (e.g., rubber) and can be compressed between the ring gear 90 and the front gear housing 77 during assembly of the impact wrench 10. Alternatively, the seal 156 can also be made of other materials suitable for preventing lubricant from leaking from the gear housing 76.

[0025] During operation of the impact wrench 10, an operator pulls the trigger 62 to activate the motor 42, which continuously drives the gear assembly 66 and the camshaft 94 via the output shaft 50. As the camshaft 94 rotates, the cam balls 154 drive the hammer 130 to rotate with the camshaft 94, and the drive surfaces of the hammer lugs 140 engage the driven surfaces of the anvil lugs 142 to produce a blow and rotate the anvil 126 and tool member. After each blow, the hammer 130 moves or slides rearward along the camshaft 94, away from the anvil 126, causing the hammer lugs 140 to clear the anvil lugs 142.

[0026] As the hammer 130 moves rearward, the cam balls 154, located in the respective cam grooves 150 of the camshaft 94, move rearward in the grooves 150. The spring 134 stores a portion of the rearward energy of the hammer 130 to provide a return mechanism for the hammer 130. After the hammer lugs 140 disengage from the respective anvil lugs 142, the hammer 130 continues to rotate and move, or slide, forward toward the anvil 126 while the spring 134 releases its stored energy until the drive surfaces of the hammer lugs 140 re-engage the driven surfaces of the anvil lugs 142 to cause another impact.

[0027] Although the disclosure has been described in detail with reference to certain preferred embodiments, variations and modifications are possible within the scope and spirit of one or more independent aspects of the described disclosure. For example, although the power tool is described and illustrated herein as an impact driver 10, aspects of the present disclosure may also be implemented in other types of power tools, such as drills, cordless screwdrivers, impact drivers, rotary hammers, ratchets, grinders, precision torque tools, and the like. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 63 / 567,262

[0001]

Claims

[1] Power tool comprising: a housing having a first housing portion and a second housing portion, the first housing portion and the second housing portion together defining a head housing portion; a motor held in the head housing portion and including an output shaft; a gear housing completely enclosed by the head housing portion; a gear assembly engaging the output shaft and held in the gear housing; and a drive assembly driven by the gear assembly and held in the head housing portion. [2] Power tool according to claim 1, wherein the gear housing is arranged entirely between the first housing section and the second housing section. [3] A power tool according to claim 1 or 2, wherein the output shaft defines an axis and the gear housing includes a tab extending radially outwardly in a direction perpendicular to the axis toward the housing, the tab being received in a recess of the housing to prevent rotation of the gear housing relative to the housing. [4] Power tool according to one of the preceding claims, wherein the housing comprises a nose cap coupled to the gear housing. [5] A power tool according to claim 4, wherein the assembly comprises an anvil received in the gear housing and extending through the nose cap. [6] Power tool according to one of the preceding claims, wherein the gear housing comprises a first gear housing section, a second gear housing section and a seal between the first gear housing section and the second gear housing section. [7] A power tool according to any preceding claim, wherein the output shaft defines an axis and the gear housing is aligned with the motor along the axis. [8] A power tool according to any preceding claim, wherein the housing defines a handle housing portion, the power tool further comprising a battery receptacle in the handle housing portion adapted to receive a battery and supply power to the motor. [9] A power tool according to any preceding claim, further comprising a bushing coupled to the gear housing and rotatably supporting an anvil of the assembly, the bushing including a groove on an inner periphery that receives a lubricant to minimize friction during rotation of the anvil. [10] Power tool comprising: a housing defining a head housing portion; a motor mounted in the head housing portion and including an output shaft defining an axis; a gear housing aligned with the engine along the axis and held in the head housing portion; a gear assembly engaged with the output shaft and held in the gear housing, the gear assembly comprising: a pinion coupled to the output shaft, a plurality of planetary gears meshing with the pinion gear and a ring gear meshing with the planetary gears; a seal arranged axially between the gear housing and the ring gear; and a drive assembly driven by the planetary gears and held in the head housing portion. [11] Power tool according to claim 10, wherein the seal cooperates with a flange of the gear housing. [12] Power tool according to claim 11, wherein the seal is U-shaped in cross-section and receives the flange of the gear housing. [13] A power tool according to any one of claims 10-12, wherein the gear housing includes a tab extending radially outwardly in a direction perpendicular to the axis toward the housing, the tab being received in a recess of the housing to prevent rotation of the gear housing relative to the housing. [14] A power tool according to any one of claims 10-13, wherein the ring gear comprises a projection extending from a rear surface of the ring gear in the direction of the axis, the projection being inserted into an opening of the housing. [15] A power tool according to claim 14, wherein the opening extends through a partition in the housing separating the motor from the ring gear. [16] Power tool comprising: a housing comprising: a first housing section, a second housing portion coupled to the first housing portion, the first and second housing portions defining a head housing portion, and a nose cap coupled to the head housing portion; a motor held in the head housing portion; a gear housing supported by the head housing portion, the nose cap coupled to the gear housing; a gear assembly engaged with the engine and held within the gear housing; and a drive assembly driven by the gear assembly and held in the head housing portion. [17] The power tool of claim 16, wherein the motor defines an axis and the gear housing includes a tab extending radially outwardly in a direction perpendicular to the axis toward the housing, the tab being received in a recess of the housing to prevent rotation of the gear housing relative to the housing. [18] Power tool according to claim 17, wherein the tab is a first of a plurality of tabs extending radially outward in a direction perpendicular to the axis toward the housing, the recess in the housing is a first of a plurality of recesses in the housing, and each tab is received in one of the plurality of recesses in the housing to prevent rotation of the gear housing relative to the housing. [19] A power tool according to claim 17 or 18, wherein the gear housing includes a projection extending radially outwardly in a direction perpendicular to the axis toward the housing, the projection being received in a recess of the nose cap to prevent rotation of the gear housing relative to the nose cap. [20] Power tool according to one of claims 16-19, wherein the gear housing is completely enclosed by the head housing portion.

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