Machine tool with a decoupling device

Abstract

The invention relates to a machine tool (1), in particular a drill hammer or chisel hammer, comprising a housing (5), which has a handle region (7, 27), and comprising an assembly (9), which comprises a striker device (11) and a drive device (13). The assembly (9) is arranged substantially within the housing (5) and is arranged so as to be movable relative to the housing (5). The center of gravity (15) of the assembly (9) is arranged at a distance to a striking axis (19), which defines the longitudinal direction (Z). At least one front decoupling device (23), with respect to the longitudinal axis (Z), and at least one rear decoupling device (25) are provided. The decoupling devices (23, 25) are operatively connected to the housing (5) and to the assembly (9). The at least one rear decoupling device (25) is designed to allow a movement of the assembly (9) relative to the housing (5) in all three spatial directions (X, Y, Z) and has spring properties and / or damping properties in all three spatial directions (X, Y, Z).

Description

[0001] Hilti Corporation in Schaan

[0002] Principality of Liechtenstein

[0003] Machine tool with a decoupling device

[0004] The present invention relates to a machine tool, in particular a drilling and / or chisel hammer, according to the type defined in more detail in the preamble of patent claim 1.

[0005] DE 10 2020 216 538 A1 discloses a rotary hammer and / or chisel hammer comprising an outer housing and an inner housing. The inner housing is arranged within the outer housing, wherein the inner housing comprises a drive unit and a percussion unit. A vibration damping unit with a vibration damping element is provided for damping vibrations occurring during operation, by means of which a main handle connected to the outer housing is decoupled from the inner housing. The inner housing is mounted rotatably relative to the outer housing about a rotation axis arranged in the region of an instantaneous center of the percussion unit.

[0006] In this design, the mobility of the inner housing relative to the outer housing is limited to the rotational axis, which is located in the area of ​​the instantaneous center of the impact mechanism unit. However, the instantaneous center of rotation cannot be determined precisely and can fluctuate during operation of the machine tool. The damping of the outer housing relative to the inner housing is reduced in this case.

[0007] It is an object of the present invention to provide a machine tool, in particular a hammer drill or chisel hammer, in which improved damping properties of the outer housing can be achieved in all operating states compared to an assembly comprising a percussion device.

[0008] The object is achieved by the subject matter of independent claim 1. Further advantageous embodiments of the invention can be found in the corresponding subclaims.

[0009] A machine tool, in particular a hammer drill or chisel hammer, is provided with a housing having a handle area and an assembly comprising a percussion mechanism and a drive device, wherein the assembly is arranged substantially within the housing and is arranged such that it can move relative to the housing, wherein a center of gravity of the assembly is arranged at a distance from an impact axis defining a longitudinal direction, wherein at least one front decoupling device and at least one rear decoupling device are provided with respect to the longitudinal axis, wherein the decoupling devices are operatively connected on the one hand to the housing and on the other hand to the assembly.

[0010] According to the invention, it is proposed that the at least one rear decoupling device is designed to enable movement of the assembly relative to the housing in all three spatial directions and has spring properties and / or damping properties in all three spatial directions.

[0011] A machine tool designed according to the invention has the advantage that the housing is protected to the desired extent in all operating states of the machine tool against vibrations, oscillations, and the like arising in the area of ​​the assembly during operation of the machine tool, and the vibrations occurring in this area are dampened to the desired extent. This is achieved by the rear decoupling device or anti-vibration device having spring properties and / or damping properties in all spatial directions of a Cartesian coordinate system. Vibrations are effectively reduced both in chisel operation, in which a chisel connected to a tool holder is moved back and forth in an oscillating manner in the direction of the impact axis, and in hammer drilling operation, in which the tool additionally performs a rotating movement around the impact axis.

[0012] Vibrations and accelerations occur during drilling or chiseling operations due to the interaction between the substrate and the tool connected to the tool holder. The greatest accelerations occur in the percussion axis direction, the longitudinal direction, or the Z-direction. Due to the angular design of the machine tool, in which the center of mass of the assembly is not located on the percussion axis, vibrations also occur in the vertical direction perpendicular to the percussion axis, or in the Y-direction, during operation of the machine tool. Furthermore, vibrations also occur in the transverse direction, or the X-direction, during operation of the machine tool, for example, caused by imbalance forces in the drive system.

[0013] With the solution according to the invention, during operation of the machine tool, a user who holds the machine tool, for example, in at least one gripping area, in particular the gripping area, can be easily adjusted to a very low value, which allows a long working time with a machine tool according to the invention.

[0014] The three spatial directions are defined in particular by a longitudinal direction, a transverse direction, and a vertical direction of the machine tool. The longitudinal direction (Z-direction), the transverse direction (X-direction), and the vertical direction (Y-direction) are perpendicular to each other, with the longitudinal direction corresponding to an impact axis. A plane spanned by the transverse direction and the vertical direction is perpendicular to the longitudinal direction.

[0015] In an advantageous embodiment of a machine tool according to the invention, the rear decoupling device comprises a first decoupling device having spring properties and / or damping properties in a transverse direction and a vertical direction of the machine tool, and a second decoupling device having spring properties and / or damping properties in the longitudinal direction. It has been shown that with such an embodiment, particularly good damping properties can be achieved in all operating states and thus advantageously low vibrations acting on a user during operation. It is particularly advantageous if the first decoupling device additionally has spring properties and / or damping properties in the longitudinal direction.

[0016] In order to implement favorable spring properties and / or damping properties in a plane defined by the transverse and vertical directions, it is advantageous if the first decoupling device has a decoupling element extending circumferentially relative to a longitudinal axis of the decoupling device. Such a decoupling element allows spring and / or damping properties in the transverse and vertical directions to be easily adjusted.

[0017] In an advantageous embodiment of a machine tool according to the invention, the decoupling element has a cross-section that is constant in the circumferential direction of the axis or a cross-section that varies in the circumferential direction of the axis. This allows essentially identical spring and / or damping properties to be set in the vertical and transverse directions. Alternatively, different spring and / or damping properties can be easily set in the vertical and transverse directions depending on the application by varying the cross-section of the decoupling element in the circumferential direction. For example, the decoupling element has a varying material thickness in the circumferential direction for this purpose.

[0018] The decoupling element can be made of an elastomer, particularly a dynamic foam. In principle, any material with desired spring and / or damping properties can be used.

[0019] In an advantageous embodiment of a machine tool according to the invention, the first decoupling device has an element which is operatively connected to the housing and which is displaceable essentially in the longitudinal direction relative to an element which is operatively connected to the assembly. In this way, a desired large displacement of the assembly relative to the housing in the longitudinal direction is easily achieved. For example, it can be provided that the element fixed to the housing is designed as a steel pin which is connected, in particular screwed, to the housing in a form-fitting manner, wherein the element operatively connected to the assembly can be designed, for example, as a sliding bush representing a sliding partner therefor. It can also be provided that an element which is operatively connected to the assembly is provided and which is displaceable essentially in the longitudinal direction relative to an element operatively connected to the housing.

[0020] In order to reliably prevent, for example, undesired impact of the assembly on the housing in the area of ​​the first decoupling device in all operating states during operation, the element operatively connected to the housing or the element operatively connected to the assembly can be connected to the housing or the assembly under prestress by means of the decoupling element.

[0021] Particularly good damping properties can be achieved if the first decoupling device is arranged in an area between the housing and the assembly facing away from a tool holder of the machine tool, and in particular, is positioned at a particularly large distance from the front decoupling device arranged in the area of ​​a tool holder. In principle, however, the first decoupling device can be arranged in any position between the housing and the assembly.

[0022] In an advantageous embodiment of a machine tool according to the invention, the rear decoupling device comprises at least two, in particular essentially identically constructed, first decoupling devices, which are arranged at different positions between the housing and the assembly. This allows for particularly favorable spring and / or damping properties. The position and number of the first decoupling devices can be selected as desired depending on the application.

[0023] In an advantageous embodiment of a machine tool according to the invention, the rear decoupling device has at least a first decoupling device, a second decoupling device, and a third decoupling device, each arranged between the assembly and the housing, wherein the first decoupling device has spring properties and / or damping properties in a vertical direction of the machine tool, wherein the second decoupling device has spring properties and / or damping properties in a transverse direction of the machine tool, and wherein the third decoupling device has spring properties and / or damping properties in the longitudinal direction. It has been shown that particularly favorable spring and / or damping properties can be achieved in this way. All decoupling devices can additionally have spring and / or damping properties in other directions.Furthermore, all decoupling devices can enable movement of the assembly and the housing in other directions relative to each other in addition to the direction in which their spring and / or damping properties act.

[0024] In an advantageous structural embodiment, the first decoupling device has two sliding elements which are connected essentially in the vertical direction by means of at least one spring element, in particular by means of at least two spring elements, and which are mounted in a guide fixed to the housing. The sliding elements are preferably mounted in such a way that the assembly can be displaced in the longitudinal direction relative to the housing by the sliding elements. If at least two spring elements are provided, a rotational movement of the assembly relative to the housing, in particular in the transverse direction, is also possible via the spring elements. In order to be able to set a desired preload of the sliding elements relative to one another, at least one, in particular two limiting elements can be provided which limit movement of the sliding elements relative to one another in the vertical direction.

[0025] In an advantageous embodiment of a machine tool according to the invention, the second decoupling device can comprise a decoupling element that is designed to rotate around a transverse axis and is arranged on an element mounted relative to the assembly, wherein the element is guided on an element fixed to the housing. A second decoupling device designed in this way can enable both desired spring and / or damping properties in the transverse direction and a displacement option for the assembly relative to the housing in a plane defined by the vertical and longitudinal directions.

[0026] In an advantageous embodiment of a machine tool according to the invention, the front decoupling device enables movement of the assembly relative to the housing in all three spatial directions. The front decoupling device can be designed as a plain bearing with a clearance fit.

[0027] In an advantageous embodiment of the invention, by means of which rattling of the assembly relative to the housing is reliably prevented during operation, the front decoupling device can comprise a first sliding element fixed to the housing and a second sliding element cooperating with the assembly, wherein the sliding element operatively connected to the assembly is prestressed in the radial direction with respect to the longitudinal direction. The prestress can be achieved, for example, via an annular element extending circumferentially with respect to the longitudinal direction or via a bend of the sliding element operatively connected to the assembly pointing in the radial direction with respect to the longitudinal direction.

[0028] In an advantageous embodiment of the invention, a housing-mounted sliding element of the front decoupling device can be designed with high rigidity so that the housing-mounted sliding element is not deformed, or not deformed to an undesirably large extent, for example, when a handle device is attached externally by means of a tensioning strap. For this purpose, the housing-mounted sliding element can be designed, for example, with a metallic material, in particular as a steel bushing.

[0029] In order to keep friction as low as possible when the assembly is displaced longitudinally relative to the housing, the sliding element that is operatively connected to the assembly can be made of a plastic material and the sliding element that is fixed to the housing can be made of a metallic material.

[0030] The sliding element operatively connected to the assembly can be designed as a so-called Slydring ® or as a ring slotted in the circumferential direction, in particular a steel ring or plastic ring, in particular with a lubricating varnish coating.

[0031] In an advantageous embodiment of a machine tool according to the invention, the front decoupling device has a first sliding element fixed to the housing, a second sliding element fixed to the assembly and a third sliding element, wherein the third sliding element is displaceable substantially in the longitudinal direction relative to the second sliding element fixed to the assembly, and wherein the first sliding element has a sliding surface curved in the longitudinal direction, which is designed to correspond to a sliding surface of the third sliding element, wherein by an interaction of the sliding surface of the first sliding element with the sliding surface of the third sliding element, the assembly is rotatable substantially about a transverse direction and / or about a vertical direction relative to the housing.Such a design of the front decoupling device enables, in particular, a large displacement of the assembly relative to the housing in the longitudinal direction and a rotation of the assembly relative to the housing in the region of the front decoupling device about the transverse direction and / or about the vertical direction.

[0032] The third sliding element can be designed in multiple parts in the circumferential direction, in particular two, three, four, or more parts, to facilitate assembly of the third sliding element, in particular to the first sliding element. To connect multiple parts, the individual parts can have grooves on the inside with end regions that are widened in the circumferential direction, via which adjacent parts of the third sliding element can be connected to one another via connecting elements.

[0033] In an advantageous embodiment of a machine tool according to the invention, at least one support device is provided which is arranged transversely between the assembly and the housing, the support device comprising a support element prestressed in the transverse direction. The support device represents a decoupling device by means of which oscillations and / or vibrations occurring in the area of ​​the assembly, in particular during operation of the machine tool, are dampened and transmitted to the housing to a lesser extent. Rattling of the assembly can be prevented by arranging such a support device between the assembly and the housing in this area, in particular on both sides in the transverse direction, and moreover, displacement of the assembly relative to the housing in the vertical direction is easily enabled.A low-friction design provides for the support device to have a metallic support element fixed to the housing, which interacts with a plastic element of the assembly. A reversal of the function is also possible.

[0034] To limit any displacement of the assembly relative to the housing, stops can be provided in all directions on both sides, fixed to the housing and / or the assembly, whereby the number and position of the stops can be varied as required in each direction depending on the application.

[0035] Further advantages will become apparent from the following description of the figures. Various embodiments of the present invention are illustrated in the figures. The figures, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0036] They show:

[0037] Fig. 1 is a simplified side sectional view of a first embodiment of a power tool designed as a hammer drill, comprising an outer housing and an assembly arranged in the housing, comprising a percussion mechanism and a drive mechanism, wherein the assembly is displaceable relative to the housing by means of a front decoupling device and a rear decoupling device, wherein the assembly is shown in a position without external forces acting; Fig. 2 is a representation of the power tool corresponding to Fig. 1, wherein the assembly is shown in a rear position resting against a stop when an external force is acting;

[0038] Fig. 3 is a sectional view of the machine tool according to Fig. 1 and Fig. 2 in a vertical direction

[0039] Fig. 4 is a sectional view of the machine tool corresponding to Fig. 1, wherein the assembly is rotated about a transverse axis relative to the housing when an external force acts;

[0040] Fig. 5 is a sectional view of the machine tool corresponding to Fig. 3, wherein the assembly is rotated about a vertical axis relative to the housing when an external force acts;

[0041] Fig. 6 is a sectional view of the machine tool according to Fig. 1;

[0042] Fig. 7 is a sectional view of the machine tool according to Fig. 6 without the assembly;

[0043] Fig. 8 is a sectional view of the assembly-side elements of the rear

[0044] decoupling device;

[0045] Fig. 9 is a further sectional view of the assembly-side elements of the rear

[0046] decoupling device;

[0047] Fig. 10 is a sectional view of the machine tool according to Fig. 6, wherein a

[0048] Support device is shown in more detail;

[0049] Fig. 11 is a three-dimensional view of the machine tool according to Fig. 6, wherein the support device can be seen in more detail;

[0050] Fig. 12 is a sectional view of a first embodiment of the front decoupling device of the machine tool according to Fig. 6;

[0051] Fig. 13 is a three-dimensional view of the front decoupling device according to Fig. 12;

[0052] Fig. 14 is a three-dimensional view of the assembly with an alternatively designed front decoupling device of the machine tool according to Fig. 6;

[0053] Fig. 15 is a sectional view of the front decoupling device according to Fig. 14; Fig. 16 is a three-dimensional view of an element of the front decoupling device according to Fig. 14 in isolation;

[0054] Fig. 17 is a three-dimensional view of the element of the front decoupling device according to Fig. 14 in an alternative embodiment;

[0055] Fig. 18 is a three-dimensional view of an alternatively designed machine tool;

[0056] Fig. 19 is a three-dimensional view of a section of the machine tool according to Fig. 18, wherein a rear decoupling device can be seen in more detail;

[0057] Fig. 20 is a sectional view of part of the rear decoupling device of the machine tool according to Fig. 18;

[0058] Fig. 21 is a sectional view of the front decoupling device of the machine tool according to Fig. 18;

[0059] Fig. 22 a three-dimensional view of a first sliding element of the front

[0060] Decoupling device according to Fig. 21;

[0061] Fig. 23 a three-dimensional view of a third sliding element of the front

[0062] Decoupling device according to Fig. 21;

[0063] Fig. 24 a three-dimensional view of an alternatively designed rear

[0064] decoupling device;

[0065] Fig. 25 is a rear view of the rear decoupling device according to Fig. 24; and

[0066] Fig. 26 is a plan view of the rear decoupling device according to Fig. 24 and Fig. 25.

[0067] Examples of implementation:

[0068] Fig. 1 to Fig. 5 show a first embodiment of a machine tool 1, which in the present case is designed as a hammer drill or combination hammer, but in an alternative embodiment can also be designed as a chisel hammer or the like.

[0069] The machine tool 1 is designed in the present case as a cordless machine tool with a battery 3, but can be provided for mains operation in an alternative embodiment.

[0070] The machine tool 1 is designed here in an angular construction and has a housing 5 with a rear handle area 7 in a D shape. The housing 5, which can be designed in one or more parts, is firmly connected to the handle area 7 that can be grasped by a user. In this case, the housing 5 is divided in the longitudinal direction Z and designed in a so-called pot construction. Alternatively, the housing 5 can also have, in particular, two housing halves that can be connected to one another in the transverse direction X and can be designed in a so-called shell construction.

[0071] Arranged within the housing 5 is a structural unit or assembly 9, which comprises a conventionally designed percussion mechanism 11 and a drive device 13 designed as an electric motor, which is designed to drive the percussion mechanism 11. In this case, the assembly 9 is L-shaped.

[0072] In this case, assembly 9 enables drilling or chiseling operation. In chiseling operation, tool 17 oscillates back and forth in the direction of the impact axis. In drilling or hammer drilling operation, the tool also performs a rotating movement around the impact axis.

[0073] The machine tool 1 has, in a conventional manner, a tool holder 16, via which a tool 17, for example a chisel or the like, can be detachably and operatively connected to the structural unit 9.

[0074] The figures also show a longitudinal direction designated Z or Z-direction, a vertical direction designated Y or Y-direction, and a transverse direction designated X or X-direction. X, Y, and Z are axes of a Cartesian coordinate system and are perpendicular to each other. Without the action of an external force, the longitudinal direction Z is congruent with the impact axis, which is defined by a central axis of the tool or tool holder 16.

[0075] In the embodiment shown, 15 indicates a center of gravity of the structural unit 9, which is arranged below the longitudinal direction Z with respect to the vertical direction Y in the illustrations shown and is thus spaced from the longitudinal direction Z.

[0076] The structural unit 9 can have a separate inner housing 21, which in particular comprises the percussion device 11 and the drive device 13 or within which the percussion device 11 and the drive device 13 are in particular almost completely arranged.

[0077] For example, Fig. 1 shows a front decoupling device 23 and a rear decoupling device 25, which can generally be designed with one decoupling device or multiple decoupling devices. In the illustrated embodiment, the front decoupling device 23 is arranged in front of the rear decoupling device 25 in the longitudinal direction Z, i.e., closer to the tool holder 16 and in an area facing away from the rear handle area 7.

[0078] For example, in Fig. 1 and Fig. 3, a front gripping area 27 or lateral handle is visible, which in this case can be releasably connected to the housing 5 in the area of ​​the front decoupling device 23, for example by means of a tensioning strap. In this case, the front gripping area 27 extends essentially in the transverse direction X, but can be arranged on the housing 5 in a manner that is continuously adjustable in the circumferential direction relative to the longitudinal direction Z.

[0079] The structural unit 9 is mounted relative to the housing 5 via both the front decoupling device 23 and the rear decoupling device 25, wherein the structural unit 9 is displaceable relative to the housing 5 both in the region of the front decoupling device 23 and in the region of the rear decoupling device 25 in the longitudinal direction Z, in the transverse direction X, and in the vertical direction Y. The displacement possibility s in the longitudinal direction Z is, for example, a maximum of approximately 10 mm, but can be up to 20 mm or more in other designs. The displacement possibility in the transverse direction X and in the vertical direction Y is essentially identical in the present case, wherein the displacement possibility s in the longitudinal direction Z is approximately 7 times as large as the displacement possibility in the transverse direction X and in the vertical direction Y.

[0080] To define a maximum travel path in the transverse direction X, in the vertical direction Y, and in the longitudinal direction Z, stops 37 are provided, each defining a defined end position of the structural unit 9 relative to the housing 5. The number and position of the stops 37 can generally be freely selected, with at least one, in particular two, stops 37 preferably being provided for each direction X, Y, and Z on both sides of the structural unit 9.

[0081] During drilling or chiseling operations of the machine tool, the interaction between the surface being machined and the tool 17 generates vibrations or accelerations that primarily act in the direction of the impact axis. Due to the angular design of the machine tool 1, in which the center of mass 15 of the structural unit 9 is not located on the impact axis or longitudinal axis Z, this also generates vibrations or accelerations transverse to the impact axis in the vertical direction Y. For example, due to unbalance forces in the area of ​​the drive device 13, vibrations or accelerations in the transverse direction X also occur during operation of the machine tool 1.

[0082] During operation of the machine tool 1, vibrations and accelerations arise in the area of ​​the structural unit 9. These can be transmitted via the front decoupling device 23 and the rear decoupling device 25 to the housing 5, which has the front handle area 27 and the rear handle area 7. The aim of the decoupling devices 23, 25 is to reduce or dampen as much as possible the vibrations and accelerations that arise in the area of ​​the structural unit 9 during operation of the machine tool 1.

[0083] The assembly 9 is shown in Fig. 1 in the rest position, in which the machine tool 1 is not operating, or in which the assembly 9 is in the front end position in contact with the front stop 37a. In Fig. 2, the assembly 9 is shown in the rear end position and with the maximum deflection in the longitudinal direction Z, in which the assembly 9 is in contact with the stops 37b and 37c.

[0084] In the embodiment according to Fig. 1 to Fig. 5, a first lateral stop 37d and a second lateral stop 37e are provided, which limit a movement path of the assembly 9 relative to the housing 5 in the transverse direction X.

[0085] In addition, an upper stop 37f and a lower stop 37g are provided, which limit a movement path of the assembly 9 relative to the housing 5 in the vertical direction Y.

[0086] In the following, the rear decoupling device 25 is first described in more detail.

[0087] The rear decoupling device 25 has two first decoupling devices 31, 33 and a second decoupling device 35.

[0088] The second decoupling device 35 of the rear decoupling device 25 has spring properties and / or damping properties in the longitudinal direction Z and is designed here as a spring device with an axis of action substantially in the longitudinal direction Z.

[0089] The spring device 35, designed here as a cylindrical helical spring, presses the assembly 9 relative to the housing 5 in Fig. 1 into the front end position, in which the assembly 9 rests against the front stop 37a. In Fig. 2, the spring device 35 is shown in a maximally tensioned position. The spring device 35 assumes this position when the assembly 9 is in the rear end position relative to the housing 5, in which the assembly rests against the rear stops 37b, 37c.

[0090] A plurality of spring devices 35 can also be provided, for example two spring devices 35 arranged at a distance from one another in the transverse direction X can be provided. Alternatively or additionally, two spring devices 25 arranged at a distance from one another in the vertical direction Y can also be provided. In the exemplary embodiment according to Fig. 1 to Fig. 5, two essentially identically constructed first decoupling devices 31, 33 are provided, the first decoupling device 31 being arranged on a left-hand side of the machine tool 1 between the assembly 9 and the housing 5 and the first decoupling device 33 being arranged on a right-hand side of the machine tool 1 between the assembly 9 and the housing 5. In principle, only one such first decoupling device 31, 33 can be provided, which is arranged at any position between the assembly 9 and the housing 5.It is particularly advantageous if a distance between a decoupling device 29 of the front decoupling device 23 and the first decoupling device 31 and / or 33 of the rear decoupling device 25 in the longitudinal direction Z is as large as possible.

[0091] In Fig. 4 and Fig. 5, it is shown in a greatly exaggerated manner that, during operation of the machine tool 1, the assembly 9 can rotate relative to the housing 5 both about an axis running in the transverse direction X and about an axis running in the vertical direction Y. Rotation about an axis running in the longitudinal direction Z is also possible. The front decoupling device 23 and the rear decoupling device 25 are designed in such a way that they enable such rotations and, in particular, can also dampen vibrations or accelerations transmitted thereby.

[0092] Fig. 1 to Fig. 5 also show a further first decoupling device 36, which is arranged in a lower region of the machine tool 1 in the vertical direction Y between the assembly 9 and the housing 5. The further first decoupling device 36 is optional and can, if necessary, improve spring and / or damping properties.

[0093] In Fig. 6 to Fig. 9, the rear decoupling device 25 has, in addition to two second decoupling devices 35 designed as spring devices, a single first decoupling device 31.

[0094] The first decoupling device 31 according to Fig. 6 to Fig. 9 corresponds in structure to the first decoupling devices 31 and 33 according to Fig. 1 to Fig. 5. The first decoupling device 31 according to Fig. 6 to Fig. 9 is described in more detail below.

[0095] The first decoupling device 31 has a first sliding element 39, which here is designed as a pin-shaped element with a central axis 49. The pin-shaped element 39, designed for example as a steel pin, is connected to the housing 5 in a form-fitting manner by means of a screw connection via a thread 41 arranged in the longitudinal direction Z in the rear end region. The first decoupling device 31 further has a second sliding element 43 which interacts with the first sliding element 39 and serves as a sliding partner therefor, which second sliding element 43 is designed as a sliding bushing in this case. The sliding bushing 43 interacts via a decoupling element 45 with a bearing block 47 fixed to the assembly. The bearing block 47 is connected to a gear housing of the assembly 9 via a form-fitting connection.

[0096] The decoupling element 45 is fixed here in the direction of the central axis 49 relative to the sliding bushing 43. For this purpose, the sliding bushing 43, which is preferably made of plastic, is preferably clipped into the decoupling element 45. In an outer region in the radial direction relative to the central axis 49, the decoupling element is fixed in the direction of the central axis 49 via a bushing 51 and the bearing block 47.

[0097] It can also be provided that the decoupling element 45 is glued to the sliding bush 43 and / or to the bearing block 47.

[0098] The decoupling element 45 is tubular here with a substantially constant wall thickness. In an alternative embodiment, the decoupling element 45 can have a varying wall thickness on the circumferential side relative to the central axis 49.

[0099] The decoupling element 45 is made of an elastomer. In the rest position shown in Fig. 8, the decoupling element 45 has a preload in the radial direction of the central axis 49 in order to achieve the desired radial stiffness in the transverse direction X and vertical direction Y.

[0100] In the area of ​​the first decoupling device 31, a rotation of the assembly 9 relative to the housing 5 is possible.

[0101] In the present case, spring receiving mandrels for a spring device 33 designed as a compression spring in the vertical direction Y are attached to the bearing block 47.

[0102] In this case, two front stops 37a are provided, which are designed as rubber buffers and are connected to the gearbox housing.

[0103] In addition to the embodiment shown in Fig. 6 with a first decoupling device 31, a further, substantially identically constructed first decoupling device can also be provided, which can be arranged in a lower region of the assembly 9 with respect to the vertical direction Y and in a rear region with respect to the longitudinal direction Z. In particular, such a further first decoupling device can be arranged in the region of the drive device 13.

[0104] Fig. 24 to Fig. 26 show an alternative embodiment of the rear decoupling device 25. A first decoupling device 53 is designed with an asymmetrical sheet metal spring or leaf spring 55, which is preferably coated with anti-friction varnish. A steel pin 57 connected to the housing 9 serves as a sliding partner for the leaf spring 55, with the leaf spring 55 at least partially enclosing the steel pin 57 in one end region. The leaf spring 55 is arranged on the assembly 9 by means of a bearing block 59, with the bearing block 59 in this case having two spring pins 61a, 61b for interacting with two spring devices 33.

[0105] Fig. 10 and Fig. 11 show a first lateral support device 63 and a second lateral support device 65. The first lateral support device 63 and the second lateral support device 65 are substantially symmetrical and structurally identical to one another, with the first lateral support device 63 being described below as representative of the second lateral support device 65.

[0106] The support devices 63, 65 can represent part of the rear decoupling device 25 and thus also be decoupling devices which serve to dampen the movement of the housing 5 relative to the assembly 9 during operation of the machine tool 1.

[0107] The first lateral support device 63 is arranged in the transverse direction X between the assembly 9 and the housing 5. The first lateral support device 63 has a support element 67 prestressed in the transverse direction X, which on the one hand is fixedly connected to the housing via a positive connection and on the other hand is connected to a first sliding element designed as a sliding plate 69 by means of two fastening areas or webs arranged spaced from one another in the vertical direction Y.

[0108] A stiffness of the support element 67 in the transverse direction X can be easily adjusted by a corresponding choice of material for the support element 67, for example made of an elastomer, and / or by a corresponding shape of the support element 67.

[0109] The sliding plate 69 is, for example, glued to the support element 67 and extends substantially in the vertical direction Y and is intended to cooperate with a second sliding element 71, which in the present case is formed by a plastic housing 73 of the drive device 13.

[0110] The interaction of the sliding plate 69 and the housing 73 of the drive device 13 enables a wear-free or low-wear displacement of the assembly 9 relative to the housing 5.

[0111] The first and second lateral support devices 63, 65 can absorb the large forces that occur during operation between the assembly 9 and the housing 5, while reliably preventing hard impacts that could lead to rattling. The elastic bearing in the transverse direction X, which is slightly preloaded in the transverse direction X, requires no play between the assembly 9 and the housing 5 in the transverse direction X.

[0112] In Fig. 12 and Fig. 13, a first embodiment of the decoupling device 29 of the front decoupling device 23 is shown in more detail.

[0113] The front decoupling device 29 has a first sliding element 75 fixed to the housing and a second sliding element 77 interacting with the assembly 9. The second sliding element 77 is arranged in a groove 79 of the assembly and is fixed substantially in the longitudinal direction Z relative to the assembly. The second sliding element 77 is prestressed in the radial direction with respect to the longitudinal direction Z. For this purpose, a further groove 81 is provided radially within the groove 79, in which an O-ring 83 is arranged. The O-ring 83 applies a force to the second sliding element 77 acting outward in the radial direction.

[0114] The first sliding element 75 is designed here as a steel bushing and is positively connected to the housing 5. The steel bushing 75 is designed to be so solid that it counteracts, to the desired extent, a deformation of the housing 9 in the area of ​​the front handle section 27 by connecting it by means of a tensioning band and the resulting non-uniform circumferential forces.

[0115] The second sliding element 77 is designed here with a slotted tubular plastic ring. Preferably, the second sliding element 77 is designed as a so-called Slydring®. The selected material pairing of the first sliding element 75 and the second sliding element 77 achieves good sliding properties, which enables a displacement of the sliding elements 75 and 77 relative to one another during operation, particularly in the longitudinal direction Z. The interaction of the O-ring 83 and the second sliding element 77 enables rotation of the assembly 9 relative to the housing 5 in this area.

[0116] Fig. 14 to Fig. 16 show an alternatively designed decoupling device 85 of the front decoupling device 23. The decoupling device 85 has the first sliding element 75 and a second sliding element 87, which here is designed as a coated, slotted steel spring ring. The steel spring ring 87 is guided in the groove 79 of the assembly 9 and is fixed in particular in the longitudinal direction Z. The steel spring ring 87 is bent in the longitudinal direction Z and rests with end regions in the longitudinal direction Z in the groove 79 and, in a central region in the longitudinal direction Z, against the first sliding element 75.

[0117] The middle region of the second sliding element 87 rests against the first sliding element 75 and slides against the first sliding element 75 when the assembly 9 is displaced relative to the housing 5 in the longitudinal direction Z. The second sliding element 87 preferably has a lubricating varnish coating to improve sliding properties.

[0118] In the installed position, the steel spring ring 87 is preloaded in the radial direction, whereby the radial stiffness can be adjusted via the thickness of the sheet metal.

[0119] Fig. 17 shows an alternative embodiment of a second sliding element 89, which has a plurality of recesses 90 circumferentially in both end regions. By adjusting the number and arrangement of the recesses, the radial stiffness of the second sliding element 89 can be easily adjusted to the desired extent.

[0120] Fig. 18 to Fig. 23 show an alternatively designed machine tool 91, which is fundamentally comparable to machine tool 1. The following essentially addresses the differences from machine tool 1, and otherwise reference is made to the explanations regarding machine tool 1.

[0121] The front decoupling device 23 has a decoupling device 93 which has a first sliding element 95 fixed to the housing, a second sliding element 97 fixed to the assembly and a third sliding element 99.

[0122] The first sliding element 95 is designed as a bushing and is positively connected to the housing 5. Preferably, the first sliding element 95 is made of a metallic material. The first sliding element 95 has, in a central region in the longitudinal direction Z, a circumferentially extending curved recess 101, which is provided for interaction with the third sliding element 99 and forms an inner surface 102.

[0123] The second sliding element 97 is part of the assembly 9 and has a hollow cylindrical portion 103. The second sliding element 97 is preferably made of a metallic material.

[0124] The third sliding element 99 in the present case has three parts 105, 107, 109, which are essentially structurally identical to one another. The parts 105, 107, 109 are each designed as a segment of a tube and have an inner surface 111 facing inwards in the radial direction with respect to the longitudinal direction Z, which inner surface is part of a circular cross-section with a constant radius in the longitudinal direction Z. An outer surface 113 of the parts 105, 107, 109 facing outwards in the radial direction with respect to the longitudinal direction Z is spherical and has a curvature with a constant radius in the transverse direction X with respect to the longitudinal direction Z. The third sliding element 99 is preferably made of a plastic.The parts 105, 107, 109 each have a groove 115, 117 in their outer regions in the circumferential direction, wherein the grooves 115, 117 have an enlarged width in the longitudinal direction Z in their region pointing in the circumferential direction towards an end region of the respective part 105, 107, 109. The parts 105, 107, 109 can each be connected to one another via connecting elements 119, which are each inserted into grooves 115, 117 of adjacent parts 105, 107, 109.

[0125] To assemble the decoupling device 93, the first sliding element 95 is first positively connected to the housing 5. Subsequently, the three parts 105, 107, 109 of the third sliding element 99 are inserted into the curved recess 101 of the first sliding element 95 and connected to each other via the connecting elements 119. Finally, the second sliding element 97 can be inserted with the assembly in the longitudinal direction Z.

[0126] The second sliding element 97 and the third sliding element 99 form a sliding pairing that enables displacement of the assembly 9 in the region of the decoupling device 93 in the longitudinal direction Z relative to the housing 5. Friction is advantageously low due to the selected material pairing.

[0127] Two circumferentially adjacent parts 105, 107, 109 of the third sliding element 99 are slightly spaced apart from each other in the circumferential direction. This distance between the second sliding element 97 and the third sliding element 99 enables rotation of the assembly 9 relative to the housing 5 in the region of the decoupling device 93 about the transverse direction X and the vertical direction Y.

[0128] The rear decoupling device 25 of the machine tool 91 has, in the present case, two first decoupling devices 121, 123, in the present case two second decoupling devices 125, 127 and a third decoupling device 129.

[0129] In the present case, two first decoupling devices 121 and 123 are provided, which are designed essentially mirror-symmetrically to a longitudinal center plane formed by the longitudinal direction Z and the vertical direction Y. In the following, the first decoupling device 121 assigned to the left side is described as representative of the first decoupling device 123 assigned to the right side.

[0130] The first decoupling device 121 has spring properties and / or damping properties in the vertical direction Y of the machine tool 91. For this purpose, the first decoupling device 121 has two sliding elements 131, 133, which in the basic position are spaced apart from one another in the vertical direction Y, wherein two spring devices 135, 137 are arranged spaced apart from one another in the longitudinal direction Z, which press the sliding elements 131, 133 apart with a force acting in the vertical direction Y. The sliding elements 131, 133 can be displaced relative to one another in the vertical direction Y against a spring force of the spring devices 135, 137 and can be rotated relative to one another about the transverse direction X.

[0131] The sliding elements 131, 133 each have wedge-shaped surfaces 140 in their end regions pointing in the longitudinal direction Z.

[0132] A bearing 139 is provided which is connected to the assembly 9 and which each has an angle profile 141, 143 spaced apart from one another in the longitudinal direction Z. It can be provided that one sliding element 131, 133, for example the lower sliding element 131 in the vertical direction Y, is firmly connected to the assembly 9. It can also be provided that both sliding elements 131, 133 are loosely connected to the bearing 139.

[0133] An angle profile 141 or 143 arranged in an end region interacts with a wedge-shaped surface 140 of the first sliding element 131 and a wedge-shaped surface 140 of the second sliding element 133 and limits a maximum distance between the sliding elements 131, 133 in the vertical direction Y. The spring devices 135, 137 are designed such that the sliding elements 131, 133, with a maximum spacing in the vertical direction Y, act upon a force acting outwards in the vertical direction Y.

[0134] A guide 145 fixed to the housing is provided, which has a guide channel 147 pointing essentially in the longitudinal direction Z. The guide 145 is preferably made of a metallic material. The guide channel 147 has an extension in the vertical direction Y that essentially corresponds to a maximum extension of surfaces of the sliding elements 131, 133 pointing outwards in the vertical direction Y. As a result, the assembly 9 is guided in the region of the second decoupling device 121 essentially in the longitudinal direction Z relative to the housing 5. The guide channel 147 is designed such that it prevents or severely limits any movement of the sliding elements 131, 133 relative to the guide 145 in the transverse direction X.

[0135] The angle profiles 141, 143 are designed in such a way that during operation they do not hinder the movement of the sliding elements 131, 133 relative to one another to the desired extent, which movement is transmitted by the assembly 9 relative to the housing 5 and by interaction with the guide 145.

[0136] In the present case, two second decoupling devices 125 and 127 are provided, which are designed essentially mirror-symmetrically to a longitudinal center plane formed by the longitudinal direction Z and the vertical direction Y. In the following, the second decoupling device 125 assigned to the left side is described as representative of the second decoupling device 127 assigned to the right side.

[0137] The second decoupling device 125 has spring and / or damping properties in the transverse direction X of the machine tool.

[0138] The second decoupling device 125 has a displacement element 151, which in this case has a pin-shaped region 153 and a substantially plate-shaped end region 155. In an end region facing away from the plate-shaped end region 155, the displacement element 151 has a shoulder 159.

[0139] The pin-shaped region 153 has an axis 157 extending substantially in the transverse direction X. A hollow cylindrical decoupling element 149 is arranged circumferentially of the pin-shaped region 153, directly on the pin-shaped region 153. The decoupling element 149 is arranged in the longitudinal direction of the axis 157 between the plate-shaped end region 155 and the shoulder 159 and is preferably prestressed in the longitudinal direction of the axis 157.

[0140] The decoupling element 149 projects outwards beyond the shoulder 159 in the radial direction of the axis 157 in the area of ​​the shoulder and interacts in this area with a bearing 161 fixed to the assembly, in this case both in the radial direction of the axis 157 and in the direction of the axis 157 with the bearing 161.

[0141] The displacement element 151 interacts, via the plate-shaped region 155, with a metallic guide 163 arranged on the housing 5. The displacement element 151 and the guide 163 abut one another in the transverse direction X, in particular due to the preload of the decoupling element 149 acting in the direction of the axis 157 and thus in the transverse direction X. The interaction of the guide 163 with the displacement element 151 allows a displacement of the assembly 9 relative to the housing 5 in the longitudinal direction Z and in the vertical direction Y through a sliding movement.

[0142] The third decoupling device 129 is designed essentially comparable to the second decoupling device 33 of the machine tool 1 and is designed as a spring device with spring and / or damping properties in the longitudinal direction Z.

[0143] Due to the interaction of the first decoupling devices 121, 123, the second decoupling devices 125, 127 and the third decoupling device 129, the assembly 9 can be displaced in the region of the rear decoupling device 25 in the longitudinal direction Z, in the transverse direction X and in the vertical direction Y relative to the housing 5, wherein movements of the assembly 9 relative to the housing 5 in the longitudinal direction Z, in the transverse direction X and in the vertical direction Y are damped particularly favorably, so that vibrations acting on a user during operation of the machine tool 91 are advantageously low.

[0144] In an alternative embodiment, it can be provided that the rear decoupling device 25 has only the first decoupling devices 121, 123 and the third decoupling device 129 and no second decoupling devices 125, 127.

[0145] This can be particularly advantageous for machine tools 91 which only have a chisel operation.

Claims

Patent claims:

1. A machine tool (1, 91), in particular a hammer drill or chisel hammer, comprising a housing (5) having a handle area (7, 27) and an assembly (9) comprising a percussion mechanism (11) and a drive device (13), wherein the assembly (9) is arranged substantially within the housing (5) and is arranged to be movable relative to the housing (5), wherein a center of gravity (15) of the assembly (9) is arranged at a distance from a percussion axis (19) defining a longitudinal direction (Z), wherein at least one front decoupling device (23) and at least one rear decoupling device (25) are provided with respect to the longitudinal axis (Z), wherein the decoupling devices (23, 25) are operatively connected on the one hand to the housing (5) and on the other hand to the assembly (9), characterized in thatthat the at least one rear decoupling device (25) is designed to enable movement of the assembly (9) relative to the housing (5) in all three spatial directions (X, Y, Z) and has spring properties and / or damping properties in all three spatial directions (X, Y, Z).

2. Machine tool according to claim 1, characterized in that the rear decoupling device (25) has a first decoupling device (31, 33; 53) which has spring properties and / or damping properties in a transverse direction (X) and a vertical direction (Y) of the machine tool (1), and wherein a second decoupling device (33) is provided which has spring properties and / or damping properties in the longitudinal direction (Z).

3. Machine tool according to claim 2, characterized in that the first decoupling device (31, 33; 53) has a decoupling element (45) extending circumferentially to an axis (49) of the first decoupling device (31; 85) extending in the longitudinal direction (Z).

4. Machine tool according to claim 3, characterized in that the decoupling element (45) has a cross-section that is constant in the circumferential direction of the axis (49) or a cross-section that varies in the circumferential direction of the axis (49).

5. Machine tool according to one of claims 3 or 4, characterized in that the decoupling element (45) is made of an elastomer.

6. Machine tool according to one of claims 2 to 5, characterized in that the first decoupling device (31, 33; 53) is a housing (5) operatively connected Element (39; 75) which is displaceable substantially in the longitudinal direction (Z) relative to an element (43; 87, 89) operatively connected to the assembly (9).

7. Machine tool according to claim 6, characterized in that the element (39) operatively connected to the housing (5) or the element (43) operatively connected to the assembly (9) is connected to the housing (5) or the assembly (9) by means of the decoupling element (45) under prestress.

8. Machine tool according to one of claims 2 to 7, characterized in that the first decoupling device (31, 33; 53) is arranged in a region facing away from a tool holder (16) of the machine tool (1; 91) between the housing (5) and the assembly (9).

9. Machine tool according to one of claims 1 to 8, characterized in that the rear decoupling device (25) has at least two, in particular substantially identically constructed first decoupling devices (31, 33), which are arranged at different positions between the housing (5) and the assembly (9).

10. Machine tool according to one of claims 1 to 9, characterized in that the rear decoupling device (25) has at least one first decoupling device (121, 123), at least one second decoupling device (125, 127) and at least one third decoupling device (129), wherein the first decoupling device (121, 123) has spring properties and / or damping properties in a vertical direction (Y) of the machine tool (91), wherein the second decoupling device (125, 127) has spring properties and / or damping properties in a transverse direction (X) of the machine tool (91), and wherein the third decoupling device (129) has spring properties and / or damping properties in the longitudinal direction (Z).

11. Machine tool according to claim 10, characterized in that the first decoupling device (121, 123) has two sliding elements (131, 133) which are connected substantially in the vertical direction (Y) by means of at least one spring device (135, 137), in particular by means of at least two spring devices (135, 137), and which are mounted in a guide (145) fixed to the housing.

12. Machine tool according to one of claims 10 or 11, characterized in that the second decoupling device (125, 127) has a decoupling element (149) which is designed to run circumferentially with respect to an axis (157) extending in the transverse direction (X), which is arranged on an element (151) mounted opposite the assembly (9), wherein the element (151) is guided on an element (145) fixed to the housing. Machine tool according to one of claims 1 to 12, characterized in that the front decoupling device (23) has a first sliding element (75) fixed to the housing and a second sliding element (77) cooperating with the assembly (9), wherein the second sliding element (77) cooperating with the assembly (9) is prestressed in the radial direction with respect to the longitudinal direction (Z).Machine tool according to one of claims 1 to 13, characterized in that the front decoupling device (23) has a first sliding element (95) fixed to the housing, a second sliding element (97) fixed to the assembly, and a third sliding element (99), wherein the third sliding element (99) is displaceable substantially in the longitudinal direction (Z) relative to the second sliding element (97) fixed to the assembly, and wherein the first sliding element (95) has a curved sliding surface (102) which is designed to correspond to a sliding surface (113) of the third sliding element (99), wherein, through interaction of the sliding surface (102) of the first sliding element (95) with the sliding surface (113) of the third sliding element (99), the assembly (9) is rotatable substantially about a transverse direction (X) and / or about a vertical direction (Y) relative to the housing (5).Machine tool according to one of claims 1 to 14, characterized in that at least one support device (63, 65) arranged in the transverse direction (X) between the assembly (9) and the housing (5) is arranged, wherein the support device (63, 65) has a support element (67) prestressed in the transverse direction (X).

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