IMPACT WRENCH

摘要

To improve the durability of a bearing mechanism such as a rolling bearing that is provided between a secondary hammer and a spindle in an impact wrench configured to firmly tighten screws by applying an impact in the rotational direction of an anvil, using a primary hammer and the secondary hammer, a technique is provided in which a rolling bearing is used as the bearing mechanism, the inner circumference of the secondary hammer is press-fitted to an outer ring of the rolling bearing, and a gap is created between the outer circumference of a spindle and an inner ring of the rolling bearing. The created gap can exhibit the effect of cushioning precession rotation of the secondary hammer to reduce the radial load that is applied to the rolling bearing, and, as a result, improve the durability of the rolling bearing and extend the life of the bearing.

主权项

1. An impact wrench comprising:
a driving unit; a spindle configured to be rotated by the driving unit; an anvil arranged in front of the spindle in a direction of a rotational axis of the spindle; a primary hammer that is capable of rotating about the rotational axis of the spindle and moving in the direction of the axis; a secondary hammer having a cylindrical part in which the primary hammer is housed and into which the spindle is inserted, and that rotates synchronously with the primary hammer; and a rotary impact mechanism that impulsively engages the primary hammer with the anvil to rotate the anvil about the axis, wherein a bearing mechanism that is subjected to a load in the radial direction with respect to the rotational axis of the spindle is arranged between the secondary hammer and the spindle, separately from both the secondary hammer and the spindle, and the secondary hammer is pivotally supported by the spindle.