CN-122003314-A - Impact driver hammer

CN122003314ACN 122003314 ACN122003314 ACN 122003314ACN-122003314-A

Abstract

An impact drive assembly (110, 210) for an impact driver (100) is provided that includes an anvil (115, 215), a hammer (112, 212), a cam shaft (111, 211), and a stabilizing bearing. The inner surface of the hammer channel (114, 214) in the hammer head (121, 221) may include a hammer motion surface (123, 223). The cam shaft (111, 211) may include a cam shaft moving surface (125, 225) and a rotational input interface (127, 227). The cam shaft (111, 211) may extend through the hammer channel (114, 214) such that movement of the hammer (112, 212) relative to the cam shaft (111, 211) may cause the hammer head (121, 221) to repeatedly impact the anvil lug (120, 220) with rotational and axial forces due to the operative coupling of the hammer motion surface (123, 223) with the cam shaft motion surface (125, 225). The stabilizing bearings may be disposed in contact with and between the inner surface of the hammer passages (114, 214) and the outer surface of the cam shaft (111, 211) to permit relative rotational movement and provide radial support through contact with the cam shaft (111, 211) and the hammer (112, 212).

Inventors

XU HUANGSHENG
LIU YONGKANG

Assignees

捷可勃斯夹头制造（苏州）有限公司
艾沛克斯品牌公司

Dates

Publication Date: 20260508
Application Date: 20231011

Claims (20)

1. An impact drive assembly for an impact driver, the impact drive assembly comprising: An anvil comprising an anvil shaft and an anvil lug, the anvil shaft configured to serve as a rotary output interface for the impact drive assembly; a hammer comprising a hammer head and an annular body having an interior hammer channel, an interior surface of the hammer channel comprising a hammer motion surface and a hammer stabilizing surface; A biasing element; A cam shaft including a cam shaft moving surface, a cam shaft stabilizing surface, and a rotational input interface for the impact drive assembly, the cam shaft extending through the hammer channel, and A friction reducing surface disposed in operative coupling with the hammer stabilizing surface or the cam shaft stabilizing surface such that the friction reducing surface is stationary relative to one of the hammer stabilizing surface or the cam shaft stabilizing surface and rotatable relative to the other of the hammer stabilizing surface or the cam shaft stabilizing surface, wherein a coefficient of friction of the friction reducing surface is less than a coefficient of friction of the one of the hammer stabilizing surface or the cam shaft stabilizing surface; Wherein the cam shaft moving surface is configured to operably couple with the hammer moving surface to form an impact motion interface that moves the hammer between a loading position and an impact position in response to rotation of the cam shaft relative to the hammer; wherein in the loading position, the hammer has moved axially away from the anvil to compress the biasing element into a loaded state, and in the impact position, the biasing element has been released from the loaded state, moving the hammer axially and rotationally to impact the anvil such that the hammer head rotationally impacts the anvil lug; Wherein the friction reducing surface is configured to rotationally interact with the hammer stabilizing surface or the cam shaft stabilizing surface to facilitate rotational and axial movement of the hammer relative to the cam shaft.
2. The impact drive assembly of claim 1, further comprising a sleeve bearing comprising the friction reducing surface, the sleeve bearing having a cylindrical sleeve shape, comprising an outer surface configured to contact the hammer stabilizing surface and an inner surface configured to contact the cam shaft stabilizing surface, wherein the outer surface or the inner surface is the friction reducing surface.
3. The impact drive assembly of claim 1, wherein the cam shaft moving surface comprises a cam shaft groove and the hammer motion interface comprises a hammer groove; wherein the impact drive assembly further comprises a moving ball bearing disposed within the cam shaft groove and the hammer groove; Wherein the cam shaft stabilizing surface is an outer cylindrical surface disposed between the rotary input interface and the cam shaft moving surface.
4. The impact drive assembly of claim 3, further comprising a friction reducing member comprising the friction reducing surface; Wherein the friction reducing member includes an inner cylindrical surface that is larger than the outer cylindrical surface of the cam shaft stabilizing surface of the cam shaft to allow the outer cylindrical surface of the cam shaft stabilizing surface of the cam shaft to fit within the inner cylindrical surface of the friction reducing member; wherein the outer surface of the friction reducing member is in contact with the hammer stabilizing surface and the inner cylindrical surface of the friction reducing member is in contact with the cam shaft stabilizing surface.
5. The impact drive assembly of claim 1, wherein a cam shaft-anvil friction reducing surface is disposed between the cam shaft and the anvil.
6. The impact drive assembly of claim 1, further comprising a ball bearing including the friction reducing surface.
7. The impact drive assembly of claim 1, wherein the biasing element is a coil spring; Wherein the hammer includes an annular groove configured to receive a first end of the coil spring; wherein the cam shaft includes a flange positioned to contact the second end of the coil spring.
8. The impact drive assembly of claim 1, wherein the cam shaft extends through the hammer channel and into a cavity in the anvil; Wherein an anvil ball bearing is disposed between the anvil and the cam shaft such that the anvil and the cam shaft are free to rotate relative to each other.
9. The impact drive assembly of claim 1, wherein the hammer comprises a plurality of hammer heads and the anvil comprises a plurality of anvil lugs; Wherein, in the loaded position, the plurality of hammer heads lie in a different plane than the plurality of anvil lugs; Wherein in the impact position, the plurality of hammer heads lie in the same plane as the plurality of anvil lugs.
10. The impact drive assembly of claim 1, wherein the hammer is urged to move axially relative to the cam shaft solely by one or more moving ball bearings disposed in corresponding grooves in the cam shaft moving surface and the hammer moving surface.
11. An impact drive assembly for an impact driver, the impact drive assembly comprising: An anvil comprising an anvil lug, the anvil configured to serve as a rotary output interface for the impact drive assembly; a hammer comprising a hammer head and an annular body having an interior hammer passage, an interior surface of the hammer passage comprising a hammer motion surface; A cam shaft including a cam shaft moving surface and a rotary input interface for the impact drive assembly, the cam shaft extending through the hammer channel such that movement of the hammer relative to the cam shaft repeatedly impacts the anvil lug with rotational and axial forces due to operative coupling of the hammer moving surface with the cam shaft moving surface, and A stabilizing bearing is disposed in contact with and between the inner surface of the hammer channel and the outer surface of the cam shaft to permit relative rotational movement and to provide radial support through contact with the cam shaft and the hammer.
12. The impact drive assembly of claim 11, wherein the stabilizing bearing is a sleeve bearing formed in a cylindrical sleeve shape.
13. The impact drive assembly of claim 11, wherein the cam shaft moving surface comprises a cam shaft groove and the hammer motion interface comprises a hammer groove; wherein the impact drive assembly further comprises a moving ball bearing disposed within the cam shaft groove and the hammer groove; Wherein the cam shaft stabilizing surface is an outer cylindrical surface disposed between the rotary input interface and the cam shaft moving surface.
14. The impact drive assembly of claim 13, wherein the stabilizing bearing includes an inner cylindrical surface that is larger than an outer cylindrical surface of the cam shaft to allow the outer cylindrical surface of the cam shaft to fit within the inner cylindrical surface of the stabilizing bearing; Wherein an outer surface of the stabilizing bearing is in contact with the inner surface of the hammer and the inner cylindrical surface of the friction reducing member is in contact with the outer surface of the cam shaft.
15. The impact drive assembly of claim 11, further comprising a snap ring disposed within a snap ring recess of the inner surface of the hammer to retain the stabilizing bearing within the hammer channel.
16. The impact drive assembly of claim 11, wherein the stabilizing bearing comprises one or more stabilizing ball bearings.
17. The impact drive assembly of claim 11 further comprising a coil spring; Wherein the hammer includes an annular groove configured to receive a first end of the coil spring; wherein the cam shaft includes a flange positioned to contact the second end of the coil spring.
18. The impact drive assembly of claim 11, wherein the cam shaft extends through the hammer channel and into a cavity in the anvil; Wherein an anvil ball bearing is disposed between the anvil and the cam shaft such that the anvil and the cam shaft are free to rotate relative to each other.
19. The impact drive assembly of claim 11, wherein the stabilizing bearing moves axially with the hammer relative to the cam shaft and anvil.
20. An impact driver, comprising: A bit interface configured to secure a bit for rotationally interacting with a workpiece; A motor; A control system configured to control a rotational operation of the motor, and An impact drive assembly; Wherein, this impact drive assembly includes: An anvil comprising an anvil lug, the anvil configured as a rotary output interface of the impact drive assembly, the rotary output interface operably coupled to the bit interface; A biasing element; A hammer comprising a hammer head and an annular body having an interior hammer passage, an interior surface of the hammer passage comprising a hammer motion surface; A cam shaft including a cam shaft moving surface and a rotary input interface for the impact drive assembly, the rotary input interface operatively coupled to the motor, the cam shaft extending through the hammer channel, wherein movement of the hammer relative to the cam shaft, due to the operative coupling of the hammer moving surface to the cam shaft moving surface, causes the ram head to repeatedly impact the anvil lug with rotational and axial forces in association with compression and release of the biasing element, and A stabilizing bearing is disposed in contact with and between the inner surface of the hammer channel and the outer surface of the cam shaft to permit relative rotational movement between the hammer and the cam shaft and to provide radial support through contact with the cam shaft and the hammer.

Description

Impact driver hammer Technical Field Example embodiments relate generally to power tool technology and, in particular, to impact drivers. Background An impact driver (e.g., an impact wrench) applies repeated rotational impact forces to an internal anvil to produce a rotational output that may be used to act on a workpiece (e.g., a fastener). Such abrupt and repetitive rotational outputs have proven useful in a variety of situations, such as for removing fasteners (e.g., screws, bolts, nuts, etc.) that rust, seal, corrode, or are otherwise difficult to remove, for drilling applications, etc. Internal impacts between the hammer and anvil of such impact drivers involve repeated rotational movements and collisions to create the vibration characteristics of the driver rotation. These movements may occur at high frequencies for relatively long periods of time, resulting in heating of components (e.g., the hammer and central cam shaft) that are in contact and subject to relative movement. Such heating may cause the component to slightly deform or otherwise change motion properties, resulting in, for example, hammer wobble. Such variations in hammer motion may cause unintended interactions between components, resulting in, for example, the hammer wedging into a certain position and stopping. Accordingly, innovations are desired to address the technical issues of frictional heating and associated impact driver assembly failure. Disclosure of Invention According to some example embodiments, an impact drive assembly for an impact driver is provided. The impact drive assembly may include an anvil, a hammer, a biasing element, a cam shaft, and a friction reducing surface. The anvil may include an anvil shaft and an anvil lug. The anvil shaft may be configured to serve as a rotary output interface for the impact drive assembly. The hammer may include a hammer head and an annular body having an internal hammer passage. The inner surface of the hammer channel may include a hammer motion surface and a hammer stabilizing surface. The cam shaft may include a cam shaft moving surface, a cam shaft stabilizing surface, and a rotational input interface for the impact drive assembly. The cam shaft may extend through the hammer channel. The friction reducing surface may be configured to be operably coupled with the hammer stabilizing surface or the cam shaft stabilizing surface such that the friction reducing surface is stationary relative to one of the hammer stabilizing surface or the cam shaft stabilizing surface. Further, the friction reducing surface may be rotatable relative to the other of the hammer stabilizing surface or the cam shaft stabilizing surface. The friction reducing surface may have a coefficient of friction less than a coefficient of friction of one of the hammer stabilizing surface or the cam shaft stabilizing surface. The cam shaft moving surface may be configured to operably couple with the hammer moving surface to form an impact motion interface that moves the hammer between the loading position and the impact position in response to rotation of the cam shaft relative to the hammer. In the loading position, the hammer has moved axially away from the anvil to compress the biasing element into the loading state, and in the impact position, the biasing element has been released from the loading state, moving the hammer axially and rotationally to impact the anvil such that the hammer head rotationally impacts the anvil lug. The friction reducing surface may be configured to rotationally interact with the hammer stabilizing surface or the cam shaft stabilizing surface to facilitate rotational and axial movement of the hammer relative to the cam shaft. According to some example embodiments, an impact drive assembly for an impact driver is provided. The impact drive assembly may include an anvil, a hammer, a cam shaft, and a stabilizing bearing. The anvil may include an anvil lug. The anvil may be configured to function as a rotary output interface for the impact drive assembly. The hammer may include a hammer head and an annular body having an internal hammer passage. The inner surface of the hammer channel may include a hammer motion surface. The cam shaft may include a cam shaft moving surface and a rotational input interface for the impact drive assembly. The cam shaft may extend through the hammer channel such that movement of the hammer relative to the cam shaft causes the hammer head to repeatedly impact the anvil lug with rotational and axial forces due to the operative coupling of the hammer motion surface and the cam shaft motion surface. A stabilizing bearing may be provided in contact with and between the inner surface of the hammer channel and the outer surface of the cam shaft to permit relative rotational movement and provide radial support through contact with the cam shaft and the hammer. According to some example embodiments, there is provided an impact driver including a bit interface, a motor,