Hand-held power tool with a mechanical percussion mechanism
A hand-held power tool has a housing in which a drive motor for driving a percussion mechanism is arranged. The percussion mechanism has a percussion piston arranged in a hammer tube for displacement along an associated percussion axis, via a connecting rod. The percussion mechanism is assigned an eccentric for driving the connecting rod in rotation. A reduction-gear mechanism driven by the drive motor has a first spur gear arranged along the percussion axis between the drive motor and the eccentric. The eccentric is arranged on a second spur gear. The first spur gear meshes with teeth of the second spur gear. At least some of the teeth of the second spur gear are positioned perpendicularly to the percussion axis, between the percussion axis and a plane arranged parallel to the percussion axis. A bearing element of the eccentric arranged towards the percussion axis is arranged in the plane.
1 . A hand-held power tool, comprising:
a housing;
a drive motor arranged in the housing;
a mechanical percussion mechanism driven by the drive motor, the percussion mechanism comprising:
a hammer tube arranged at least partially in the housing;
a percussion piston arranged in the hammer tube; and
a connecting rod via which the percussion piston is driven in a linear oscillating manner along a percussion axis;
an eccentric configured to drive the connecting rod;
a reduction-gear mechanism, which is arranged along the percussion axis between the drive motor and the eccentric and is configured to be driven by the drive motor, the reduction-gear mechanism comprising a first spur gear; and
a second spur gear on which the eccentric is arranged, the second spur gear having teeth with which the first spur gear meshes, at least a portion of the teeth of the second spur gear being positioned, in a direction perpendicular to the percussion axis, between the percussion axis and a first plane defined parallel to the percussion axis,
wherein:
the eccentric is mounted at a first position nearer the percussion axis and a second position further from the percussion axis, and the eccentric is mounted at the first position by a first bearing element that is arranged in the first plane;
the first spur gear is positioned, in the direction perpendicular to the percussion axis, between the percussion axis and a second plane defined parallel to the percussion axis;
a second bearing element on an output side of a motor shaft of the drive motor is arranged in the second plane; and
the drive motor is arranged on a side of the percussion axis opposite the first plane.
2 . The hand-held power tool according to claim 1 , wherein the eccentric and the second spur gear are integrally formed.
3 . The hand-held power tool according to claim 2 , wherein the reduction-gear mechanism comprises the first spur gear and a third spur gear that are connected to each other or are integrally formed.
4 . The hand-held power tool according to claim 1 , wherein:
the percussion mechanism has a trough-shaped percussion mechanism housing having a bottom portion; and
the bottom portion comprises a first bearing point for the first bearing element, a second bearing point for mounting the eccentric at the second position, a third bearing point for mounting the reduction-gear mechanism, and a fourth bearing point for mounting the output side of the motor shaft.
5 . The hand-held power tool of claim 4 , wherein:
the trough-shaped percussion mechanism housing comprises a fifth bearing point for mounting the hammer tube; and
the fifth bearing point is oriented perpendicular to the first bearing point, the second bearing point, the third bearing point, and the fourth bearing point.
6 . The hand-held power tool according to claim 4 , wherein:
an outer side of the percussion mechanism housing is arranged at a first distance to the percussion axis;
an outer side of a motor housing of the drive motor is arranged at a second distance to the percussion axis; and
the first distance and the second distance are diametrically opposite to each other.
7 . The hand-held power tool according to claim 1 , wherein an overall center of gravity of the hand-held power tool is arranged at least within predetermined tolerances on the percussion axis.
8 . The hand-held power tool according to claim 1 , wherein the drive motor is configured as an electronically commutated motor.
9 . The hand-held power tool according to claim 1 , wherein the hand-held power tool is configured as a drill hammer or a chisel hammer.
10 . The hand-held power tool according to claim 1 , wherein the first plane is arranged, in the direction perpendicular to the percussion axis, between the second plane and the percussion axis.
11 . The hand-held power tool according to claim 1 , wherein a stator of the drive motor is arranged entirely on the side of the percussion axis opposite the first plane.
12 . The hand-held power tool according to claim 1 , wherein the eccentric includes an eccentric pin that interfaces with the connecting rod, the eccentric pin being arranged on the percussion axis.