Hand-held power tool, particularly a rotary and/or chisel hammer, having a vibration absorbing unit

A hand-held power tool, in particular an impact driver, an impact drill, or a rotary hammer, is proposed, which has a drive unit and/or output with at least one line of action, which produces at least oscillations along the line of action. In order to reduce these oscillations, the hand-held power tool is equipped with at least one vibration absorber unit. The vibration absorber unit has at least one mobile vibration absorbing element, which has at least one degree of freedom of movement. This degree of freedom of movement encloses at least one angle not equal to zero with the line of action.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a 35 USC 371 application of PCT/EP2008/064044 filed on Oct. 17, 2008.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a hand-held power tool, in particular an impact driver, an impact drill, or a rotary hammer, having at least one drive unit and/or output. The drive unit and/or output has at least one line of action, which is defined in a rotary hammer, for example, by the axial action direction of an impact mechanism. At least along this line of action, the drive unit and/or output produces oscillations, which can be transmitted in the form of vibrations to a housing and/or handle of the power tool. Users of the power tool find these vibrations unpleasant. In order to reduce these oscillations/vibrations, the power tool is equipped with at least one vibration absorber unit.

2. Description of the Prior Art

A variety of hand-held power tools with vibration absorber units for reducing oscillation are already known. Among others, EP 1 252 976 A1 has disclosed a vibration absorber unit, which, when used in hand-held power tools operated in a hammering mode such as rotary and/or chisel hammers, exerts a damping action on vibrations that propagate along a main oscillation axis extending parallel to the line of action of an impact mechanism. To this end, EP 1 252 976 A1 uses a so-called inertial vibration absorber that has a vibration absorbing element, which is supported so that it is able to move in an axial direction parallel to the line of action of the impact mechanism between two return springs. In this case, the vibration absorbing element is embodied as a mass element, also referred to as a vibration absorbing mass. By means of this arrangement, the vibration absorbing element functions as a counter-oscillator, which is displaced from a rest position by the oscillations propagating along the line of action and follows the oscillations in a delayed fashion due to its inertia. The return springs in turn damp the displacements of the vibration absorbing element, thus drawing energy from the oscillations. Because of their embodiment as a mass/spring system, vibration absorber units of this kind preferably act on a narrowly delimited frequency spectrum.

In addition, EP 1 439 038 A1 and EP 1 464 449 A2 among others have disclosed vibration absorbing systems that are actuated by different driving mechanisms. In these arrangements, the driving mechanisms couple the axially mobile vibration absorbing element to the drive unit and/or output producing the oscillations. These vibration absorbing systems, however, are also situated so that the vibration absorbing element moves axially along an axis parallel to the line of action of the drive unit and/or output.

In hand-held power tools, which in addition to an impact drive, also have a rotary drive for the tool, vibrations do not occur only in the axial direction, i.e. parallel to the line of action of the impact mechanism. In particular, rotatory vibrations occur due to the recoiling of a tool that is driven at least in rotary fashion during the machining of a work piece. In addition, in hand-held power tools in which the center of mass is situated far away from a tool axis, tilting moments occur, which excite vibrations transverse to the impact direction.

ADVANTAGES AND SUMMARY OF THE INVENTION

The hand-held power tool according to the invention, has at least one drive unit and/or output, which has at least one line of action. In hand-held power tools operated in a hammering fashion, the line of action is defined by a movement axis of an impact mechanism; the line of action is also referred to here as the impact axis. The hand-held power tool according to the invention also has at least one vibration absorber unit for reducing oscillations produced by the drive unit and/or output. The vibration absorber unit has at least one mobile vibration absorbing element. The vibration absorbing element according to the invention has at least one degree of freedom, which encloses at least one angle W1not equal to zero with the line of action. Through this arrangement, the vibration absorber unit is also able, in a structurally simple way, to damp oscillation modes that propagate in nonparallel fashion in relation to the line of action of the drive unit and/or output.

A preferred embodiment of the vibration absorber unit has additional degrees of freedom, in particular in three dimensions and/or with regard to rotation. In a particularly inexpensive way, this broadens the action of the vibration absorber unit to other oscillation modes in the vibration spectrum of the hand-held power tool according to the invention.

A particularly simple embodiment of a vibration absorber unit according to the invention is achieved in that a degree of freedom of the mobile vibration absorbing element is embodied as a transverse movement. In this case, it must be viewed as an additional advantage that the vibration absorbing element of the vibration absorber unit according to the invention has two orthogonal movement components, the one movement component extending parallel to the line of action and the other movement component extending orthogonal to the main oscillation axis. In this way, parallel and orthogonal oscillation modes can be damped with a single vibration absorber unit.

If the vibration absorber unit according to the invention has at least one rotatory degree of freedom of movement, which corresponds to a rotational movement in a movement plane around a rotation axis, then a particularly compact design of the vibration absorber unit can be achieved in a particularly simple way. A vibration absorber unit of this kind also exerts its action particularly on rotatory oscillation modes in the vibration spectrum of the hand-held power tool according to the invention.

A particularly inexpensive form of the vibration absorber unit—in particular of the at least one vibration absorbing element—is achieved by embodying it/them in the form of at least one vibration absorbing mass.

A particularly advantageous modification of the hand-held power tool according to the invention is produced by coupling the vibration absorber unit to a forced excitation device that is able to drive the at least one vibration absorbing element. In this case, the forced excitation device cooperates with the drive unit and/or output. This advantageously makes it possible to adapt the action of the vibration absorber unit to the operating state of the hand-held power tool.

A structurally simple and at the same time, particularly flexible embodiment of the forced excitation device has at least one fluid-filled pressure chamber and at least one actuating element. The at least one vibration absorbing element is set into motion by pressure changes in the fluid that act on the actuating element.

The fluid can be a gas, in particular air, for example, or also a liquid, in particular oil.

When a gas is used, the forced excitation device acts on the actuating element in an elastic fashion due to the compressibility.

By contrast, when a liquid is used, the movement of the at least one vibration absorbing element is damped particularly well.

In an advantageous embodiment, the actuating element and the mobile vibration absorbing element are attached to, in particular of one piece with, each other.

A damping of the vibration absorber unit can be achieved in a particularly simple way by means of a damping device. In a preferred embodiment, the damping device is equipped with a fluid path and at least one throttle. In addition, the damping device has at least one actuating element connected to the at least one vibration absorbing element.

In a particularly inexpensive form, the actuating element and the at least one vibration absorbing element are attached to, in particular of one piece with, each other.

A particularly effective embodiment of a vibration absorber unit according to the invention has at least one return element. The return element produces a return force acting on the at least one mobile vibration absorbing element. This return force defines a rest position of the mobile vibration absorbing element.

Advantageous embodiments of the at least one return element have at least one translatory and/or rotatory degree of freedom.

A structurally simple embodiment of a return element is achieved when produced in the form of at least one spring element.

In another preferred embodiment, the return element according to the invention has at least one damping element. Through the action of the damping element, the movement of the at least one vibration absorbing element can be advantageously damped, particularly in boundary regions.

A particularly compact design of a hand-held power tool according to the invention is achieved by situating the vibration absorber unit in a machine housing encompassing the drive unit and/or output and/or in a handle connected to this machine housing.

An advantageous method for damping oscillations in a hand-held power tool is characterized by the placement of a vibration absorber unit having at least one mobile vibration absorbing element with at least one degree of freedom of movement in such a way that the degree of freedom of movement encloses at least one angle W1not equal to zero with the line of action of a drive unit and/or output of the hand-held power tool.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1is a schematic depiction of a rotary hammer10of the kind known from the prior art, as an example of a hand-held power tool. The rotary hammer includes an impact mechanism12, which in this case is embodied in the form of an air-cushion impact mechanism13, for example, and a drive unit14that is not shown in detail. The air-cushion impact mechanism13is situated in a frontal housing region16of a machine housing18. The machine housing18is also connected to at least one handle19. A tool holder20is situated at the end surface of the frontal housing region16. An insert tool21can be inserted into it. A variety of tool holders20are known from the literature and need not be discussed in detail here. The insert tool21, in its longitudinal span, defines a machine axis22. The air-cushion impact mechanism13is situated coaxially around this machine axis22.

The air-cushion impact mechanism13in the present example includes an axially movable piston24, an axially movable striking element26, and an axially movable impact die28. The piston24, the striking element26, and the impact die28are contained in a hammer tube30. A drive unit14that is not shown in detail sets the piston24is set into a reciprocating oscillation in the hammer tube30. By means of an air cushion32situated between the piston24and the striking element26, the striking element26is in turn set into a reciprocating oscillation so that the striking element26is able to act in a hammering fashion on the impact die28, which in turn is able to act on the insert tool20.

During operation, the drive unit14and/or the air-cushion impact mechanism13and/or the insert tool21causes oscillations that propagate axially in the form of vibrations in the machine housing18, chiefly along a line of action34. This line of action34is preferably oriented parallel to the machine axis22.

In addition to the above-outlined impact driving of the insert tool21by means of an impact mechanism12,13, known rotary hammers10also have a rotary drive of the tool holder20and the insert tool21, which is coupled to the tool holder for co-rotation and is not shown inFIG. 1.

But oscillation modes also occur that are not parallel to this main oscillation axis34. Consequently, there are known transverse oscillations oriented in various spatial directions, whose propagation direction depends, among other things, on the housing geometry, the distribution of mass, the individual drive concept, and other variables of the respective hand-held power tool.

During operation of the rotary hammer10in which the insert tool21is driven in rotary fashion, rotary oscillations occur in particular due to the recoiling of the insert tool21as it interacts with a work piece. These rotary oscillations preferably have a rotation axis that is oriented parallel to the machine axis. In this case, a rotation plane of the rotary oscillations is inclined at an angle W1not equal to zero, preferably a right angle, in relation to the machine axis22or the line of action34of the impact mechanism12.

In addition to these rotary oscillations, other oscillation modes can also occur. Particularly in hand-held power tools operated in an impact drilling mode such as rotary hammers or impact drills, the effective oscillations transmitted to the machine housing18comprise an overlapping of various oscillation modes, a non-negligible portion of said oscillations arising from oscillation modes that propagate in a direction not parallel to the line of action34.

FIG. 2ais a schematic depiction of a hand-held power tool according to the invention, in particular a rotary hammer110. In order to differentiate these reference numerals from those of the hand-held power tool according to the prior art shown inFIG. 1, they have all been augmented by100. The rotary hammer110has a machine housing118and a tool holder120situated in the frontal housing region116of the machine housing118. An insert tool121is inserted into the tool holder120. This insert tool defines a machine axis122in a way analogous to the one inFIG. 1. Also analogous to the rotary hammer10known fromFIG. 1, the rotary hammer110has an impact mechanism112,113, not shown, which establishes a line of action134, and/or a rotary drive unit, not shown. The line of action134and the machine axis122here, as is already known fromFIG. 1, are oriented parallel to each other. The hand-held power tool according to the invention is also equipped with a vibration absorber unit140.

The vibration absorber unit140has a vibration absorption axis142. The vibration absorption axis142here is embodied in the form of a vibration absorber guide rail143. This vibration absorber guide rail143is preferably rigidly connected to the machine housing118and/or to at least one supporting element, not shown in detail, that supports internal machine components. This vibration absorption axis142,143is inclined at an angle W1not equal to zero in relation to the line of action134.

The vibration absorber unit140includes at least one mobile vibration absorbing element144, which has at least one degree of freedom of movement. Preferably, the mobile vibration absorbing element144is embodied in the form of a vibration absorbing mass145. In the embodiments shown inFIGS. 2a-2e, the mobile vibration absorbing element144has at least one degree of freedom of translatory movement. Preferably, this is oriented along the vibration absorption axis142, for example parallel or coaxial to it. In the present example, the mobile vibration absorbing element144is supported on the vibration absorber guide rail143in an axially movable fashion.

The mobile vibration absorbing element144is adjoined along the vibration absorption axis142by one, preferably two, return elements146,147. The return elements146,147are supported at one end against the mobile vibration absorbing element144and at the other end against support surfaces or shoulders, not shown in detail, in the machine housing118. In the form shown here, the return elements146,147are embodied as compression springs.

The return elements146,147cause the mobile vibration absorbing element144to return to a rest position. From this rest position, the mobile vibration absorbing element144is deflected by oscillation forces, which are induced among other things by oscillations occurring during operation of the hand-held power tool. By means of its inertia, the mass of the mobile vibration absorbing element144acts in a delaying fashion on the deflection from the rest position. This draws energy from the oscillations, thus reducing the oscillation energy transmitted to the machine housing116. Since the vibration absorber unit140according to the invention performs its function by virtue of an inertia effect, it can also be referred to as a so-called inertial vibration absorber and in this specific embodiment, as a translatory inertial vibration absorber.

Through the orientation of the vibration absorber unit140that is out of parallel with the line of action134by the angle W1, it is possible to separate a movement along the vibration absorption axis142of the vibration absorbing element144into at least two movement components148,149. The first movement component148here is parallel to the line of action134. The second movement component149is perpendicular to it.

During operation of the rotary hammer110according to the invention, if oscillations occur because of the drive unit114and/or the impact mechanism112,113and/or the insert tool121, then the mobile vibration absorbing element144, thanks to its inertia, exerts a damping action on the oscillation amplitudes. Through the orientation of the vibration absorber unit140according to the invention, it is possible to damp oscillation modes that propagate parallel to the at least two movement components148,149of the mobile vibration absorbing element144.

FIG. 2bshows a modified embodiment of a vibration absorber unit140according to the invention. The mobile vibration absorbing element144here is contained in a vibration absorber housing150and is able to move along a vibration absorption axis142. This embodiment eliminates a vibration absorber guide rail143. Analogous to the connection of the vibration absorber guide rail143known fromFIG. 2a, the vibration absorber housing150is rigidly connected to the machine housing118and/or to at least one supporting element, not shown in detail, that supports internal machine components. On its inner circumference surface152, the vibration absorber housing150has guide means154that are not shown in detail. On its outer circumference surface, the mobile vibration absorbing element144has guide elements158, not shown here, that fit together with the guide means154.

As is already known from the preceding exemplary embodiments, return elements146,147are situated along the vibration absorption axis142in such a way that they are able to hold the mobile vibration absorbing element144in its rest position or return it to this rest position. To that end, the return elements146,147are each supported at one end against a respective end surface160of the mobile vibration absorbing element144. The inner end surfaces162,163of the vibration absorber housing150each serve as a respective second abutting support.

The operation of this embodiment corresponds to the embodiment of a translatory inertial vibration absorber known fromFIG. 2a. This embodiment permits a particularly simple manufacture in the form of a preassembled unit.

In a preferred embodiment, the mobile vibration absorbing element144also has suitable bevels160at the edges between the outer circumference surface156and the end surfaces. During a movement of the vibration absorbing element144, these bevels160prevent it from tilting in the vibration absorber housing150.

In another preferred variant—not shown here—of the exemplary embodiment fromFIG. 2b, the vibration absorbing element144is embodied in the form of a ball. This embodiment eliminates the need for providing the circumference surfaces152,156with either guide means154,158or bevels160.

FIG. 2cshows another variant of a vibration absorber unit140according to the invention, which is a combination of the examples already known fromFIGS. 2aand2b. This vibration absorbing element140also has a vibration absorber housing150that encloses the mobile vibration absorbing element144. In this case, the vibration absorbing element144is supported in movable fashion on a vibration absorber guide rail143oriented along a vibration absorption axis142. As is known fromFIG. 2a, in addition to the vibration absorbing element144, preferably two return elements146,147are provided. The support of the return elements146,147here is identical to the one known fromFIG. 2b.

The operation of this embodiment corresponds to the above-described exemplary embodiments of a translatory vibration absorber.

FIG. 2dshows a modification of the exemplary embodiment known fromFIG. 2a, with at least one, preferably two, damping elements164,165abutting the vibration absorbing element144and arranged along the vibration absorption axis142.

The operation of this embodiment is similar to the exemplary embodiments described above. The damping elements164,165, however, exert a damping action on a deflection of the vibration absorbing element144from its rest position. In this case, damping elements164,165that are in particular elastically embodied can either function directly as return elements146,147or, as depicted, can be supplemented by additional return elements146,147.

Naturally, the damping elements164,165can also be used in a function-enhancing way in other embodiments of the vibration absorber unit140according to the invention, e.g. the ones known fromFIGS. 2band2c.

Another improvement of a vibration absorber unit140according to the invention is depicted inFIG. 2e. In this case, the mobile vibration absorbing element144is situated on a curved vibration absorber guide rail166. The mobile vibration absorbing element144is supported so that it is able to move along the curved vibration absorber guide rail166. Through a suitable selection of the curvature of the curved vibration absorber guide rail166, it is possible for the oscillation-damping behavior of the vibration absorber unit140—in terms of the movement components148,149—to be adapted to apparatus-related and/or operational peculiarities of the hand-held power tool. Otherwise, the operation of this embodiment corresponds to the exemplary embodiment of a translatory vibration absorber known fromFIG. 2a.

Modifications and improvements of the vibration absorber unit140according to the invention are particularly possible by combining the features described above.

Furthermore, the person skilled in the art will find other modifications by means of alternative return elements such as sheet-metal springs, corrugated springs, spring circlips, rod springs, air springs, and other types of spring-elastic elements.

The damping elements164,165can also yield various embodiments, improvements, and modifications of a vibration absorber unit140according to the invention. The person skilled in the art is familiar with a wide variety of damping elements.

Other modifications are produced based on the specific design of the mobile vibration absorbing element144. In particular, the mobile vibration absorbing element144can be composed of two parts, three parts, or multiple parts. It is also possible to embody the geometric design of the mobile vibration absorbing element144in a way that differs from the form shown here. Thus in addition to block-shaped, it is also possible to use cylindrical, conical, and partially conical designs, as well as other designs based on combinations of geometric figures.

A multitude of embodiments can also be found in the design of the support and guidance of the vibration absorbing element144on the vibration absorber guide rail143,166and in the vibration absorber housing150. It is thus possible to provide multi-beam vibration absorber guide rails143,166. In addition, the vibration absorbing element144in the vibration absorber housing150can be guided over the entire area of the circumference surfaces152,156functioning as guide surfaces or can be only partially guided with suitable guide means154,158.

FIG. 3aschematically depicts another exemplary embodiment of a hand-held power tool according to the invention. The rotary hammer110shown by way of example, as is known from the preceding one, has a machine axis122extending through the machine housing118and parallel to it, a line of action134. The machine housing118contains a vibration absorber unit140, which has a vibration absorption axis142that is inclined in relation to the line of action134by an angle W1that is not equal to zero.

FIG. 3bis an enlarged, schematic depiction of the vibration absorber unit140known fromFIG. 3a. In this embodiment, the mobile vibration absorbing element144is embodied as a hollow element168, in particular a vibration absorbing ring169. The mobile vibration absorbing element144,168,196is situated around a supporting element170. In the present form, the supporting element170is embodied as a central supporting rod171. Analogous to the connection of the vibration absorber guide rail143known fromFIG. 2a, during assembly, the vibration absorber unit140according to the invention is connected, preferably rigidly, to the machine housing118and/or to at least one supporting element, not shown in detail, that supports internal machine components.

The vibration absorbing element144,168,169is connected to the supporting element170,171by means of three elastic connecting elements172that function as return elements146. The elastic connecting elements172here are distributed around the circumference of the supporting element170,171, spaced apart from one another by uniform angular distances. In a preferred embodiment, the elastic connecting elements172are embodied in the form of sheet-metal springs173.

The arrangement of one spring side173aof the sheet-metal spring173oriented parallel to the plane of the ring—corresponds to the XZ plane—according toFIG. 3bgives the mobile vibration absorbing element144,168,169at least one degree of freedom of movement that is oriented chiefly parallel to the vibration absorption axis142. By varying the strength of the sheet-metal springs173, it is possible to also achieve a non-parallel component of the degree of freedom. This degree of freedom is of a translatory nature in relation to the vibration absorption axis142and is referred to below by the letter A.

A vibration absorber unit140according to the invention embodied in this way corresponds in function to the embodiments of a translatory inertial vibration absorber known fromFIGS. 2athrough2e.

FIG. 4ashows a modified embodiment of the vibration absorber unit140according to the invention already known fromFIG. 3b. In this embodiment, the spring side173aof the sheet-metal spring173is oriented parallel to the vibration absorption axis142. This orientation gives the mobile vibration absorbing element144,168,169a predominantly rotatory degree of freedom B around the vibration absorption axis142.

The mobile vibration absorbing element144can be deflected from its rest position in one of the rotation directions by oscillation forces that are in particular induced by means of rotatory oscillation modes. If the deflection occurs due to an inertial moment of the mobile vibration absorbing element144, the excitation by the oscillation forces is delayed. The sheet-metal springs173once again exert a returning action on the mobile vibration absorbing element144, causing it to rotate back into its rest position. The vibration absorber unit140therefore exerts a predominantly damping action on rotational or torsional oscillations that propagate in particular parallel to the vibration absorption axis142in the machine housing118. The inertial vibration absorber designed in this way is referred to below as a rotatory inertial vibration absorber. The plane of action of a rotatory inertial vibration absorber is thus parallel to the rotation plane of the mobile vibration absorbing element144.

FIG. 4bshows an alternative embodiment of a vibration absorber unit140according to the invention in the form of a rotatory inertial vibration absorber. This vibration absorber unit140has a vibration absorber housing150, which contains the mobile vibration absorbing element144and serves to fasten the vibration absorber unit140in or to the machine housing118. In this embodiment, the mobile vibration absorbing element144is embodied in the form of an eccentric vibration absorbing mass145situated around a vibration absorber rotation axis174and supported so that it is able to rotate freely around this axis. A center of mass M of the mobile vibration absorbing element144,145is situated eccentric to the vibration absorber rotation axis174. In a rotation plane that corresponds to the XZ plane, a respective return element146,147is situated in each of the two rotation directions; inFIG. 4b, the return elements are connected to the vibration absorber housing150, only loading the mobile vibration absorbing element144,145in its end positions. In this way, when deflected from its rest position by oscillation forces, the mobile vibration absorbing element144,145can absorb a relatively large amount of energy before the return elements146,147cause the mobile vibration absorbing element144,145to return to this rest position.

Advantageous improvements and modifications of this embodiment of a rotatory inertial vibration absorber are possible, among other things, by adapting the form and design of the return elements146,147. Thus it can be advantageous for the return elements146,147, analogous to the embodiments of a translatory inertial vibration absorber known fromFIGS. 2athrough2e, to be embodied as compression springs that are supported between end surfaces of the mobile vibration absorbing element144,145and inner support surfaces of the vibration absorber housing150. It can also be advantageous, analogous toFIG. 2d, for the return elements146,147to be replaced or supplemented with damping elements.

FIG. 4cis a three-dimensional schematic depiction of an alternative embodiment of a hand-held power tool according to the invention, embodied in the form of a rotary hammer110that is equipped with a vibration absorber unit140embodied in the form of a rotatory inertial vibration absorber according toFIG. 4b. In this embodiment, the vibration absorber unit140is situated so that the vibration absorber rotation axis174is oriented parallel and preferably coaxial to the line of action134. The plane of action of the rotatory degree of freedom—corresponds to the XZ plane—of the vibration absorber unit here is inclined at an angle not equal to zero, preferably a right angle, in relation to the line of action134.

In an analogous fashion, other embodiments of a rotatory inertial vibration absorber, as are known fromFIG. 4a, for example, can also be provided in a hand-held power tool according to the invention.

FIG. 5ashows another preferred embodiment of a vibration absorber unit140according to the invention. This embodiment of an inertial vibration absorber represents a modification of the variants known fromFIGS. 3band4a. In this embodiment, the elastic connecting elements172are embodied in the form of rod springs176. The rod springs176are in particular elastic both parallel to the plane of the ring—corresponds to the XZ plane—of the mobile vibration absorbing element144,168,169and in the radial planes in relation to the vibration absorption axis142. The vibration absorbing element144,168,169has at least two degrees of freedom of movement A and B, where A represents a translatory degree of freedom parallel to the vibration absorption axis142and B represents a rotatory degree of freedom parallel to the plane of the ring of the vibration absorbing element144,168,169. In its operation, this embodiment corresponds to a superimposition of the embodiments already known fromFIGS. 3band4a. Such a vibration absorber unit140according to the invention is particularly suitable for damping both transverse and rotatory oscillation modes. It can thus be referred to here as a dual-mode inertial vibration absorber.

In modifications of the vibration absorber unit140according to the invention, the mobile vibration absorbing element144can have, among others, a hollow cylindrical, toroidal, or other hollow body form. By contrast with the embodiments shown in the detailed view, it is also possible for the mobile vibration absorbing element144to be composed of two parts, three parts, or multiple parts.

In the specific embodiment, the number of connecting elements172can vary between at least one, but preferably two, three, or a plurality, which incidentally also applies to all variants according toFIGS. 3b,4a, and5a. The connecting elements172can also be produced from different elastic materials such as spring steel, sheet metals, or plastics. It can also be advantageous to embody the connecting elements in the form of damping elements164or to supplement them with damping elements164.

Other variants of inertial vibration absorbers according toFIGS. 3b,4a, and5aarise from different embodiments of the supporting element170. When embodied as a holding rod171, the supporting element170can diverge from the cylindrical form shown here, in particular it is also conceivable for it to have a triangular, square, or other polygonal cross section. In addition, the supporting element170can be composed of two or more parts.

FIG. 5bschematically depicts the embodiment of a vibration absorber unit140according to the invention in the form of an alternative dual-mode inertial vibration absorber. The vibration absorber unit140has a vibration absorber guide rail143, which extends along the vibration absorption axis142and a mobile vibration absorbing element144. The mobile vibration absorbing element144is supported in an axially movable fashion on the vibration absorber guide rail143and is able to rotate around it. The mobile vibration absorbing element144here is embodied in the form of an annular disk178, for example.

The vibration absorber guide rail143and the mobile vibration absorbing element144are operationally connected to each other by means of a return element146. The return element146here is embodied in the form of a helical spring180situated around the vibration absorber guide rail143.

At its end oriented toward the mobile vibration absorbing element144, the helical spring180has an extension180athat points radially outward and is equipped with an insertion pin. With this insertion pin, the helical spring180engages in a receiving bore182in the vibration absorbing element144,178. At its other end, the helical spring180has a securing pin180boriented radially inward, which is inserted into a receiving bore183of the vibration absorber guide rail143.

This suspension gives the vibration absorber unit140according to the invention two degrees of freedom A and B, where A represents a translatory degree of freedom parallel to the vibration absorption axis142and B represents a rotatory degree of freedom in a rotation plane that corresponds to the XZ plane around the vibration absorber guide rail143. Such a vibration absorber unit140according to the invention is particularly suitable for damping both transverse and rotatory oscillation modes.

In one variant of the vibration absorbing element140according to the invention, two or more return elements146are provided.

In a preferred variant of the vibration absorbing element140according to the invention, the vibration absorber guide rail143and the vibration absorbing element144,178are operationally connected to each other by means of at least one, but preferably two, three, or more damping elements164. The damping element164here can exert a damping action on a translatory and/or rotatory movement of the vibration absorbing element144,178.

Other variations ensue from different fastening designs for connecting the vibration absorber guide rail143and/or vibration absorbing element144,178to the return element146and/or the damping element164.

Additional modifications ensue from the embodiment of the mobile vibration absorbing element144, which can, for example, have a polygonal, elliptical, or other outer contour. In addition, the mobile vibration absorbing element144can be composed of two parts, three parts, or multiple parts.

FIG. 6shows a modified embodiment of a vibration absorber unit140in the form of an inertial vibration absorber. In this case, the vibration absorber unit140includes a mobile vibration absorbing element144embodied in the form of a vibration absorbing mass145. The mobile vibration absorbing element144,145is situated on a vibration absorber rotation axis184, which is positioned in a transverse extension of a housing185and is connected to the housing185. The housing185can be either a vibration absorber housing150or the machine housing118itself The mobile vibration absorbing element144,145is rotatable in a transverse extension and is supported in axially movable fashion on the vibration absorber rotation axis184. The vibration absorber rotation axis184here is oriented at an angle W1not equal to zero in relation to the machine axis122and to the line of action134of an impact mechanism that is not shown. Together with at least one, preferably two, return elements146, the vibration absorber rotation axis184spans a vibration absorber plane186, which is oriented at an angle W2, for example a right angle, to the machine axis122and to the line of action134of an impact mechanism that is not shown.

The return elements146operationally connect the mobile vibration absorbing element144,145to the housing185; the return elements146are situated in the vibration absorber plane186, preferably perpendicular to the vibration absorber rotation axis184.

In a preferred embodiment, the return elements146are embodied as sheet-metal springs, spring bands, or helical springs. The mobile vibration absorbing element144,145thus has at least two degrees of freedom A and B, where A represents a translatory degree of freedom along the vibration absorber rotation axis184and B represents a rotatory degree of freedom around this axis. In particular, because of the orientation of the vibration absorber rotation axis184, the degree of freedom A encloses an angle W1not equal to zero with the machine axis122and the line of action134of an impact mechanism, not shown.

Such a vibration absorber unit140exerts an in particular damping action on transverse oscillations parallel to the vibration absorber rotation axis184and torsional oscillations perpendicular to the vibration absorber plane186.

Variations of this embodiment ensue, among other things, from different geometrical embodiments of the mobile vibration absorbing element144,145, which particularly in addition to the block shape shown, can be embodied in the form of a ball, an ellipsoid, or other shapes. It is also possible for the vibration absorbing element144,145to be composed of two parts, three parts, or multiple parts. In addition, the vibration absorber unit140can be embodied in the form of a preassembled unit in a separate support frame. In a preferred modification of the vibration absorber unit140, it has at least one, but preferably two, three, or more damping elements164, which exert a damping action on the deflections in the various degrees of freedom of the vibration absorbing element144,145.

The modified embodiment of a vibration absorber unit140shown inFIG. 7is embodied here in the form of a three-dimensional oscillator. The vibration absorber unit140here has a mobile vibration absorbing element144and three return elements146. The return elements146are situated in a vibration absorber plane186, each with one end connected to the vibration absorbing element144and preferably spaced apart from one another by uniform angular distances. With their opposite respective ends, the return elements146are each connected to the machine housing118, not shown here.

In the rest state, the return elements146hold the mobile vibration absorbing element144in a rest position situated in the vibration absorber plane186. The suspension of the vibration absorbing element144gives it a total of six degrees of freedom of movement; three degrees of freedom permit transverse oscillations parallel to the main axes x, y, z and another three degrees of freedom permit rotational oscillations around these main axes. Depending on the orientation of the vibration absorber plane186in relation to the machine axis122and the line of action134of an impact mechanism not shown, at least two translatory degrees of freedom are inclined in relation to this plane by an angle that is not equal to zero.

In a preferred modification of the vibration absorber unit140, at least one, but preferably two, three, or more damping elements164can be provided, which exert a damping action on the deflection in the various degrees of freedom of the mobile vibration absorbing element144. Variations of the vibration absorber unit140ensue, among other things, from the embodiment of the mobile vibration absorbing element144, which particularly in addition to the ball shape shown, can be embodied in the form of a block, an ellipsoid, or other shapes. It is also possible for the vibration absorbing element144to be composed of two parts, three parts, or multiple parts. In addition, the vibration absorber unit140can be embodied in the form of a preassembled unit in a separate support frame.

FIG. 8ashows a modification of the vibration absorber unit140already known fromFIG. 4b, supplemented by a forced excitation device188. The vibration absorber unit140has a vibration absorber housing150in which the mobile vibration absorbing element144and two return elements146are situated. The vibration absorber housing150includes a semicircular rotary oscillation chamber190and a pressure chamber192. The mobile vibration absorbing element144is supported in rotary fashion around a vibration absorber rotation axis174and together with a vibration absorbing mass145, is accommodated in the rotary oscillation chamber190. The return elements146are fastened to the dividing wall passing approximately through the center of the housing and are oriented toward the vibration absorbing mass145. The return elements146return the mobile vibration absorbing element144to a rest position.

At its end oriented into the pressure chamber192, the mobile vibration absorbing element144has an actuating element194. The actuating element194here, particularly in the rest position of the mobile vibration absorbing element144, protrudes approximately perpendicular to an alignment line193established by two line connections196that are formed onto the upper region of the vibration absorber housing150.

FIG. 8bschematically depicts a connection of the vibration absorbing element140according to the invention to a forced excitation device188. At the two line connections196, the pressure chamber192is connected via a line system to a pressure source197operationally connected to the drive unit and/or output. The pressure source197moves a fluid198that can flow into and out of the pressure chamber192via the line connections196. The fluid198can be either a gas, in particular air, or a liquid, in particular hydraulic fluid.

If the pressure source is operationally connected to the impact mechanism112, in particular the air-cushion impact mechanism113, and preferably if it is comprised by the latter, then pressure fluctuations in the pressure chamber192act on the actuating element194. The actuating element194drives the mobile vibration absorbing element144out of the rest position. The rotating movement of the vibration absorbing element144produces counter-oscillations with a frequency that is matched to the impact frequency off the impact mechanism112,113so that oscillations are actively damped in the machine housing118.

The integration of the vibration absorber unit140equipped with the forced excitation device188into a hand-held power tool is carried out according to the invention in accordance with the embodiments already known fromFIGS. 2a,3a, and4c.

In a modification, the vibration absorbing element140has damping elements164in the rotary oscillation chamber190. In particular, the rotary oscillation chamber190can be filled with a damping fluid, which damps the deflection of the mobile vibration absorbing element144.

In another embodiment, the vibration absorbing element140can include a mobile vibration absorbing element144, which is mounted in an axially movable fashion on a vibration absorber guide rail143, which is in particular oriented parallel to the alignment line193. In this embodiment, instead of the rotating movement, the vibration absorbing element144executes an axially oscillating movement.

In addition to the embodiment of a forced excitation device188described here, which follows the pressure transducer principle, it is also possible to use, among others, mechanical, electromechanical, and/or electromagnetic devices to drive the mobile vibration absorbing element144. In this case, the corresponding devices in preferred embodiments can be operationally connected to the drive unit and/or output, in particular the impact mechanism112, for example.

Through a modification, the above-described exemplary embodiment of a vibration absorbing element140according to the invention can be equipped with a damping device200in lieu of a forced excitation device188.FIG. 8coutlines this embodiment. To that end, instead of being connected to a pressure source, the line connections196are connected to a fluid reservoir204via a line connection functioning as a fluid path202. In addition, at least one throttle206is provided in the fluid path202. The fluid198in this embodiment functions passively. If the mobile vibration absorbing element144is set into motion due to inertial forces that can stem from oscillations in the machine housing118, then the actuating element194functions as a damping piston, which is moved by the fluid198.

In a preferred embodiment, the vibration absorbing element140according to the invention, together with the damping device200, can be manufactured in the form of a preassembled module.

In a preferred modification of the vibration absorbing element140according to the invention equipped with the damping device200, the at least one throttle206is embodied in the form of a variable throttle with an adjustable throttle cross-section; it is possible to provide a manual adjustment by the user through suitable adjusting means and/or an automated adjustment by means of a control unit. By adjusting the variable throttle, it is possible to adapt the damping behavior of the damping device200to the required degree.

Other advantageous embodiments of a vibration absorbing element140according to the invention can be achieved by combining features of the exemplary embodiments described above.

The specific embodiments of the individual features, which depend on the installation situation—in particular the connection to the machine housing118, have no influence on the function of the vibration absorbing element140according to the invention. These therefore merely constitute adaptations of a vibration absorbing element140according to the invention.